Specific and non-overlapping functions of testosterone and 11-ketotestosterone in the regulation of professional phagocyte responses in the teleost fish gilthead seabream.

PubMed

Aguila, S; Castillo-Briceño, P; Sánchez, M; Cabas, I; García-Alcázar, A; Meseguer, J; Mulero, V; García-Ayala, A

2013-03-01

Sex hormones, both estrogens and androgens, have a strong impact on immunity in mammals. In fish, the role of androgens in immunity has received little attention and contradictory conclusions have been obtained. However, it is well known that sex steroids are involved in fish growth, osmoregulation and gonad remodelation. In this study, we examine the in vitro effects of testosterone and 11-ketotestosterone, the two main fish androgens, on the professional phagocytes of the teleost fish gilthead seabream (Sparus aurata L.). Although both testosterone and 11-ketotestosterone failed to modulate the respiratory burst of seabream phagocytes, testosterone but not 11-ketotestosterone was able to increase the phagocytic ability of non-activated phagocytes. Curiously, 11-ketotestosterone was more powerful than testosterone at inducing the expression of its own receptor, namely androgen receptor b (ARb), in acidophilic granulocytes (AGs), but none of them affected the basal ARb expression levels in macrophages (MØ). Furthermore, although physiological concentrations of testosterone exerted a pro-inflammatory effect on both AGs and MØs, 11-ketotestosterone showed an anti-inflammatory effect in AGs and a strong pro-inflammatory effect in MØs. Interestingly, both androgens modulated the expression of toll-like receptors in these two immune cell types, suggesting that androgens might regulate the sensitivity of phagocytes to pathogens and damage signals. Testosterone and 11-ketotestosterone have a competitive effect, at least, on the modulation of the expression of some genes. Therefore, our results show for the first time a non-overlapping role for testosterone and 11-ketotestosterone in the regulation of professional phagocyte functions in fish. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of the total replacement of fish-based diet with plant-based diet on the hepatic transcriptome of two European sea bass (Dicentrarchus labrax) half-sibfamilies showing different growth rates with the plant-based diet

PubMed Central

2011-01-01

Background Efforts towards utilisation of diets without fish meal (FM) or fish oil (FO) in finfish aquaculture have been being made for more than two decades. Metabolic responses to substitution of fishery products have been shown to impact growth performance and immune system of fish as well as their subsequent nutritional value, particularly in marine fish species, which exhibit low capacity for biosynthesis of long-chain poly-unsaturated fatty acids (LC-PUFA). The main objective of the present study was to analyse the effects of a plant-based diet on the hepatic transcriptome of European sea bass (Dicentrarchus labrax). Results We report the first results obtained using a transcriptomic approach on the liver of two half-sibfamilies of the European sea bass that exhibit similar growth rates when fed a fish-based diet (FD), but significantly different growth rates when fed an all-plant diet (VD). Overall gene expression was analysed using oligo DNA microarrays (GPL9663). Statistical analysis identified 582 unique annotated genes differentially expressed between groups of fish fed the two diets, 199 genes regulated by genetic factors, and 72 genes that exhibited diet-family interactions. The expression of several genes involved in the LC-PUFA and cholesterol biosynthetic pathways was found to be up-regulated in fish fed VD, suggesting a stimulation of the lipogenic pathways. No significant diet-family interaction for the regulation of LC-PUFA biosynthesis pathways could be detected by microarray analysis. This result was in agreement with LC-PUFA profiles, which were found to be similar in the flesh of the two half-sibfamilies. In addition, the combination of our transcriptomic data with an analysis of plasmatic immune parameters revealed a stimulation of complement activity associated with an immunodeficiency in the fish fed VD, and different inflammatory status between the two half-sibfamilies. Biological processes related to protein catabolism, amino acid transaminations, RNA splicing and blood coagulation were also found to be regulated by diet, while the expression of genes involved in protein and ATP synthesis differed between the half-sibfamilies. Conclusions Overall, the combined gene expression, compositional and biochemical studies demonstrated a large panel of metabolic and physiological effects induced by total substitution of both FM and FO in the diets of European sea bass and revealed physiological characteristics associated with the two half-sibfamilies. PMID:22017880

RNA-seq of the aging brain in the short-lived fish N. furzeri - conserved pathways and novel genes associated with neurogenesis.

PubMed

Baumgart, Mario; Groth, Marco; Priebe, Steffen; Savino, Aurora; Testa, Giovanna; Dix, Andreas; Ripa, Roberto; Spallotta, Francesco; Gaetano, Carlo; Ori, Michela; Terzibasi Tozzini, Eva; Guthke, Reinhard; Platzer, Matthias; Cellerino, Alessandro

2014-12-01

The brains of teleost fish show extensive adult neurogenesis and neuronal regeneration. The patterns of gene regulation during fish brain aging are unknown. The short-lived teleost fish Nothobranchius furzeri shows markers of brain aging including reduced learning performances, gliosis, and reduced adult neurogenesis. We used RNA-seq to quantify genome-wide transcript regulation and sampled five different time points to characterize whole-genome transcript regulation during brain aging of N. furzeri. Comparison with human datasets revealed conserved up-regulation of ribosome, lysosome, and complement activation and conserved down-regulation of synapse, mitochondrion, proteasome, and spliceosome. Down-regulated genes differ in their temporal profiles: neurogenesis and extracellular matrix genes showed rapid decay, synaptic and axonal genes a progressive decay. A substantial proportion of differentially expressed genes (~40%) showed inversion of their temporal profiles in the last time point: spliceosome and proteasome showed initial down-regulation and stress-response genes initial up-regulation. Extensive regulation was detected for chromatin remodelers of the DNMT and CBX families as well as members of the polycomb complex and was mirrored by an up-regulation of the H3K27me3 epigenetic mark. Network analysis showed extensive coregulation of cell cycle/DNA synthesis genes with the uncharacterized zinc-finger protein ZNF367 as central hub. In situ hybridization showed that ZNF367 is expressed in neuronal stem cell niches of both embryonic zebrafish and adult N. furzeri. Other genes down-regulated with age, not previously associated with adult neurogenesis and with similar patterns of expression are AGR2, DNMT3A, KRCP, MEX3A, SCML4, and CBX1. CBX7, on the other hand, was up-regulated with age. © 2014 The Authors. Aging cell published by the Anatomical Society and John Wiley & Sons Ltd.

Defining Global Gene Expression Changes of the Hypothalamic-Pituitary-Gonadal Axis in Female sGnRH-Antisense Transgenic Common Carp (Cyprinus carpio)

PubMed Central

Xu, Jing; Huang, Wei; Zhong, Chengrong; Luo, Daji; Li, Shuangfei; Zhu, Zuoyan; Hu, Wei

2011-01-01

Background The hypothalamic-pituitary-gonadal (HPG) axis is critical in the development and regulation of reproduction in fish. The inhibition of neuropeptide gonadotropin-releasing hormone (GnRH) expression may diminish or severely hamper gonadal development due to it being the key regulator of the axis, and then provide a model for the comprehensive study of the expression patterns of genes with respect to the fish reproductive system. Methodology/Principal Findings In a previous study we injected 342 fertilized eggs from the common carp (Cyprinus carpio) with a gene construct that expressed antisense sGnRH. Four years later, we found a total of 38 transgenic fish with abnormal or missing gonads. From this group we selected the 12 sterile females with abnormal ovaries in which we combined suppression subtractive hybridization (SSH) and cDNA microarray analysis to define changes in gene expression of the HPG axis in the present study. As a result, nine, 28, and 212 genes were separately identified as being differentially expressed in hypothalamus, pituitary, and ovary, of which 87 genes were novel. The number of down- and up-regulated genes was five and four (hypothalamus), 16 and 12 (pituitary), 119 and 93 (ovary), respectively. Functional analyses showed that these genes involved in several biological processes, such as biosynthesis, organogenesis, metabolism pathways, immune systems, transport links, and apoptosis. Within these categories, significant genes for neuropeptides, gonadotropins, metabolic, oogenesis and inflammatory factors were identified. Conclusions/Significance This study indicated the progressive scaling-up effect of hypothalamic sGnRH antisense on the pituitary and ovary receptors of female carp and provided comprehensive data with respect to global changes in gene expression throughout the HPG signaling pathway, contributing towards improving our understanding of the molecular mechanisms and regulative pathways in the reproductive system of teleost fish. PMID:21695218

Hypoxemia-induced leptin secretion: a mechanism for the control of food intake in diseased fish.

PubMed

MacDonald, Lauren E; Alderman, Sarah L; Kramer, Sarah; Woo, Patrick T K; Bernier, Nicholas J

2014-06-01

Leptin is a potent anorexigen, but little is known about the physiological conditions under which this cytokine regulates food intake in fish. In this study, we characterized the relationships between food intake, O2-carrying capacity, liver leptin-A1 (lep-a1) gene expression, and plasma leptin-A1 in rainbow trout infected with a pathogenic hemoflagellate, Cryptobia salmositica. As lep gene expression is hypoxia-sensitive and Cryptobia-infected fish are anemic, we hypothesized that Cryptobia-induced anorexia is mediated by leptin. A 14-week time course experiment revealed that Cryptobia-infected fish experience a transient 75% reduction in food intake, a sharp initial drop in hematocrit and hemoglobin levels followed by a partial recovery, a transient 17-fold increase in lep-a1 gene expression, and a sustained increase in plasma leptin-A1 levels. In the hypothalamus, peak anorexia was associated with decreases in mRNA levels of neuropeptide Y (npy) and cocaine- and amphetamine-regulated transcript (cart), and increases in agouti-related protein (agrp) and pro-opiomelanocortin A2 (pomc). In contrast, in non-infected fish pair-fed to infected animals, lep-a1 gene expression and plasma levels did not differ from those of non-infected satiated fish. Pair-fed fish were also characterized by increases in hypothalamic npy and agrp, no changes in pomc-a2, and a reduction in cart mRNA expression. Finally, peak infection was characterized by a significant positive correlation between O2-carrying capacity and food intake. These findings show that hypoxemia, and not feed restriction, stimulates leptin-A1 secretion in Cryptobia-infected rainbow trout and suggest that leptin contributes to anorexia by inhibiting hypothalamic npy and stimulating pomc-a2. © 2014 Society for Endocrinology.

Functional and comparative genomics analyses of pmp22 in medaka fish

PubMed Central

Itou, Junji; Suyama, Mikita; Imamura, Yukio; Deguchi, Tomonori; Fujimori, Kazuhiro; Yuba, Shunsuke; Kawarabayasi, Yutaka; Kawasaki, Takashi

2009-01-01

Background Pmp22, a member of the junction protein family Claudin/EMP/PMP22, plays an important role in myelin formation. Increase of pmp22 transcription causes peripheral neuropathy, Charcot-Marie-Tooth disease type1A (CMT1A). The pathophysiological phenotype of CMT1A is aberrant axonal myelination which induces a reduction in nerve conduction velocity (NCV). Several CMT1A model rodents have been established by overexpressing pmp22. Thus, it is thought that pmp22 expression must be tightly regulated for correct myelin formation in mammals. Interestingly, the myelin sheath is also present in other jawed vertebrates. The purpose of this study is to analyze the evolutionary conservation of the association between pmp22 transcription level and vertebrate myelin formation, and to find the conserved non-coding sequences for pmp22 regulation by comparative genomics analyses between jawed fishes and mammals. Results A transgenic pmp22 over-expression medaka fish line was established. The transgenic fish had approximately one fifth the peripheral NCV values of controls, and aberrant myelination of transgenic fish in the peripheral nerve system (PNS) was observed. We successfully confirmed that medaka fish pmp22 has the same exon-intron structure as mammals, and identified some known conserved regulatory motifs. Furthermore, we found novel conserved sequences in the first intron and 3'UTR. Conclusion Medaka fish undergo abnormalities in the PNS when pmp22 transcription increases. This result indicates that an adequate pmp22 transcription level is necessary for correct myelination of jawed vertebrates. Comparison of pmp22 orthologs between distantly related species identifies evolutionary conserved sequences that contribute to precise regulation of pmp22 expression. PMID:19534778

Multiple genes for functional 6 fatty acyl desaturases (Fad) in Atlantic salmon (Salmo salar L.): gene and cDNA characterization, functional expression, tissue distribution and nutritional regulation.

PubMed

Monroig, Oscar; Zheng, Xiaozhong; Morais, Sofia; Leaver, Michael J; Taggart, John B; Tocher, Douglas R

2010-09-01

Fish are the primary source in the human food basket of the n-3 long-chain polyunsaturated fatty acids, eicosapentaenoate (EPA; 20:5n-3) and docosahexaenoate (DHA; 22:6n-3), that are crucial to the health of higher vertebrates. Atlantic salmon are able to synthesize EPA and DHA from 18:3n-3 through reactions catalyzed by fatty acyl desaturases (Fad) and elongases of very long chain fatty acids. Previously, two cDNAs encoding functionally distinct Delta5 and Delta6 Fads were isolated, but screening of a genomic DNA library revealed the existence of more putative fad genes in the Atlantic salmon genome. In the present study, we show that there are at least four genes encoding putative Fad proteins in Atlantic salmon. Two genes, Delta6fad_a and Delta5fad, corresponded to the previously cloned Delta6 and Delta5 Fad cDNAs. Functional characterization by heterologous expression in yeast showed that the cDNAs for both the two further putative fad genes, Delta6fad_b and Delta6fad_c, had only Delta6 activity, converting 47 % and 12 % of 18:3n-3 to 18:4n-3, and 25 and 7 % of 18:2n-6 to 18:3n-6, for 6Fad_b and Delta6fad_c, respectively. Both 6fad_a and 6fad_b genes were highly expressed in intestine (pyloric caeca), liver and brain, with 6fad_b also highly expressed in gill, whereas 6fad_c transcript was found predominantly in brain, with lower expression levels in all other tissues. The expression levels of the 6fad_a gene in liver and the 6fad_b gene in intestine were significantly higher in fish fed diets containing vegetable oil compared to fish fed fish oil suggesting up-regulation in response to reduced dietary EPA and DHA. In contrast, no significant differences were found between transcript levels for 6fad_a in intestine, 6fad_b in liver, or 6fad_c in liver or intestine of fish fed vegetable oil compared to fish fed fish oil. The observed differences in tissue expression and nutritional regulation of the fad genes are discussed in relation to gene structures and fish physiology. 2010 Elsevier B.V. All rights reserved.

Sex biased expression of ghrelin and GHSR associated with sexual size dimorphism in yellow catfish.

PubMed

Zhang, Jin; Ma, Wenge; He, Yan; Wu, Junjie; Dawar, Farman Ullah; Ren, Fan; Zhao, Xiaohan; Mei, Jie

2016-03-10

Sexual size dimorphism has been observed in many cultivable fish species including yellow catfish, in which male fish grow much faster than female fish. Ghrelin is a potent stimulator of pituitary growth hormone (GH) release and known to potentially promote food intake and body weight gain. In order to investigate the molecular mechanism of sexual size dimorphism in yellow catfish (Pelteobagrus fulvidraco), ghrelin and its functional receptor, growth hormone secretagogue receptor (GHSR) cDNAs were cloned. Real-time PCR indicated that both ghrelin and GHSR were more highly expressed in hypothalamus and gut of male fish than female. During normal larval development, expression of ghrelin and GHSR genes was significantly higher in males than in females. 17a-Methyltestosterone (MT) treatment enhanced the expression of ghrelin in female larval fish and GHSR in both sexes, whereas the expression of ghrelin in male larval fish increased in the beginning, then decreased as the treatment time prolonged. Furthermore, the expression of ghrelin and GHSR in male juvenile was significantly increased compared with female juvenile, in short and long term fasting periods, suggesting that male fish may have a better appetite than female during fasting. Our results demonstrate that sex difference in the expression of ghrelin and GHSR may be involved in sexual size dimorphism by regulating feeding and GH/IGF signaling in yellow catfish. Copyright © 2015 Elsevier B.V. All rights reserved.

Acute hypoxia stress induced abundant differential expression genes and alternative splicing events in heart of tilapia.

PubMed

Xia, Jun Hong; Li, Hong Lian; Li, Bi Jun; Gu, Xiao Hui; Lin, Hao Ran

2018-01-10

Hypoxia is one of the critical environmental stressors for fish in aquatic environments. Although accumulating evidences indicate that gene expression is regulated by hypoxia stress in fish, how genes undergoing differential gene expression and/or alternative splicing (AS) in response to hypoxia stress in heart are not well understood. Using RNA-seq, we surveyed and detected 289 differential expressed genes (DEG) and 103 genes that undergo differential usage of exons and splice junctions events (DUES) in heart of a hypoxia tolerant fish, Nile tilapia, Oreochromis niloticus following 12h hypoxic treatment. The spatio-temporal expression analysis validated the significant association of differential exon usages in two randomly selected DUES genes (fam162a and ndrg2) in 5 tissues (heart, liver, brain, gill and spleen) sampled at three time points (6h, 12h, and 24h) under acute hypoxia treatment. Functional analysis significantly associated the differential expressed genes with the categories related to energy conservation, protein synthesis and immune response. Different enrichment categories were found between the DEG and DUES dataset. The Isomerase activity, Oxidoreductase activity, Glycolysis and Oxidative stress process were significantly enriched for the DEG gene dataset, but the Structural constituent of ribosome and Structural molecule activity, Ribosomal protein and RNA binding protein were significantly enriched only for the DUES genes. Our comparative transcriptomic analysis reveals abundant stress responsive genes and their differential regulation function in the heart tissues of Nile tilapia under acute hypoxia stress. Our findings will facilitate future investigation on transcriptome complexity and AS regulation during hypoxia stress in fish. Copyright © 2017 Elsevier B.V. All rights reserved.

Immunotoxicology of titanium dioxide and hydroxylated fullerenes engineered nanoparticles in fish models

NASA Astrophysics Data System (ADS)

Jovanovic, Boris

2011-12-01

Nanoparticles have the potential to cause adverse effects on the fish health, but the understanding of the underlying mechanisms is limited. Major task of this dissertation was to connect gaps in current knowledge with a comprehensive sequence of molecular, cellular and organismal responses toward environmentally relevant concentrations of engineered nanoparticles (titanium dioxide -- TiO2 and hydroxylated fullerenes), outlining the interaction with the innate immune system of fish. The research was divided into following steps: 1) create cDNA libraries for the species of fathead minnow (Pimephales promelas); 2) evaluate whether, and how can nanoparticles modulate neutrophil function in P. promelas; 3) determine the changes in expression of standard biomarker genes as a result of nanoparticle treatment; 4) expose the P. promelas to nanoparticles and appraise their survival rate in a bacterial challenge study; 5) assess the impact of nanoparticles on neuro-immunological interface during the early embryogenesis of zebrafish (Danio rerio). It was hypothesized that engineered nanoparticles can cause measurable changes in fish transcriptome, immune response, and disease resistance. The results of this dissertation are: 1) application of environmentally relevant concentration of nanoparticles changed function of fish neutrophils; 2) fish exposed to nano-TiO2 had significantly increased expression of interleukin 11, macrophage stimulating factor 1, and neutrophil cytosolic factor 2, while expression of interleukin 11 and myeloperoxidase was significantly increased and expression of elastase 2 was significantly decreased in fish exposed to hydroxylated fullerenes; 3) exposure to environmental estimated concentration of nano-TiO2 significantly increased fish mortality during Aeromonas hydrophila challenge. Analysis of nano-TiO 2 distribution in fish organism outlined that the nano-TiO2 is concentrating in the fish kidney and spleen; 4) during the early embryogenesis of D. rerio exposure to nanoparticles caused shifts in gene regulation response patterns. Significant effects on gene regulation were observed on genes involved in circadian rhythm, kinase activity, vesicular transport and immune response.

Transcriptional repressor foxl1 regulates central nervous system development by suppressing shh expression in zebra fish.

PubMed

Nakada, Chisako; Satoh, Shinya; Tabata, Yoko; Arai, Ken-ichi; Watanabe, Sumiko

2006-10-01

We identified zebra fish forkhead transcription factor l1 (zfoxl1) as a gene strongly expressed in neural tissues such as midbrain, hindbrain, and the otic vesicle at the early embryonic stage. Loss of the function of zfoxl1 effected by morpholino antisense oligonucleotide resulted in defects in midbrain and eye development, and in that of formation of the pectoral fins. Interestingly, ectopic expression of shh in the midbrain and elevated pax2a expression in the optic stalk were observed in foxl1 MO-injected embryos. In contrast, expression of pax6a, which is negatively regulated by shh, was suppressed in the thalamus and pretectum regions, supporting the idea of augmentation of the shh signaling pathway by suppression of foxl1. Expression of zfoxl1-EnR (repressing) rather than zfoxl1-VP16 (activating) resulted in a phenotype similar to that induced by foxl1-mRNA, suggesting that foxl1 may act as a transcriptional repressor of shh in zebra fish embryos. Supporting this notion, foxl1 suppressed isolated 2.7-kb shh promoter activity in PC12 cells, and the minimal region of foxl1 required for its transcriptional repressor activity showed strong homology with the groucho binding motif, which is found in genes encoding various homeodomain proteins. In view of all of our data taken together, we propose zfoxl1 to be a novel regulator of neural development that acts by suppressing shh expression.

Fish oil improves lipid profile in juvenile rats with intrauterine growth retardation by altering the transcriptional expression of lipid-related hepatic genes.

PubMed

Chen, Lian-Hui; Liang, Li; Fang, Yan-Lan; Wang, Ying-Min; Zhu, Wei-Fen

2016-10-01

To determine whether maternal intrauterine undernutrition and post-weaning fish oil intake influence lipid profile in juvenile offspring, and explore the possible mechanisms at transcriptional levels. After weaning, 32 control offspring and 24 intrauterine growth retardation (IUGR) offspring were randomly allocated to standard chow or fish oil diet. At 10 weeks, fasting plasma glucose, triglycerides, total cholesterol and expressions of related hepatic genes were examined. IUGR offspring without catch-up growth tended to develop hyperglycemia, dyslipidemia and hepatic steatosis. Down-regulation of CPT-1 and LDLR at transcriptional levels were found in IUGR offspring. Early short-term fish oil intervention reversed these unfavorable changes in juvenile rats with IUGR. The mechanisms might be mediated by decreased expression of ACC-1, increased expression of CPT-1, LDLR and ABCG5. These data suggest that IUGR offspring already present lipid abnormality in juvenile stage, and early short-term fish oil consumption is beneficial to prevent these unfavorable changes.

Identification of differentially expressed genes associated with differential body size in mandarin fish (Siniperca chuatsi).

PubMed

Tian, Changxu; Li, Ling; Liang, Xu-Fang; He, Shan; Guo, Wenjie; Lv, Liyuan; Wang, Qingchao; Song, Yi

2016-08-01

Body size is an obvious and important characteristic of fish. Mandarin fish Siniperca chuatsi (Basilewsky) is one of the most valuable perciform species widely cultured in China. Individual differences in body size are common in mandarin fish and significantly influence the aquaculture production. However, little is currently known about its genetic control. In this study, digital gene expression profiling and transcriptome sequencing were performed in mandarin fish with differential body size at 30 and 180 days post-hatch (dph), respectively. Body weight, total length and body length of fish with big-size were significantly higher than those with small-size at both 30 and 180 dph (P < 0.05). 2171 and 2014 differentially expressed genes were identified between small-size and big-size fish at 30 and 180 dph, respectively. RT quantitative PCR (qPCR) analysis showed that the differential expression of 10 selected genes in mandarin fish that went through the same training procedure. The genes were involved in the growth hormone-insulin-like growth factor axis, cell proliferation and differentiation, appetite control, glucose metabolism, reproduction and sexual size dimorphism pathways. This study will help toward a comprehensive understanding of the complexity of regulation of body size in mandarin fish individuals and provide valuable information for future research.

Horizontal functional gene transfer from bacteria to fishes.

PubMed

Sun, Bao-Fa; Li, Tong; Xiao, Jin-Hua; Jia, Ling-Yi; Liu, Li; Zhang, Peng; Murphy, Robert W; He, Shun-Min; Huang, Da-Wei

2015-12-22

Invertebrates can acquire functional genes via horizontal gene transfer (HGT) from bacteria but fishes are not known to do so. We provide the first reliable evidence of one HGT event from marine bacteria to fishes. The HGT appears to have occurred after emergence of the teleosts. The transferred gene is expressed and regulated developmentally. Its successful integration and expression may change the genetic and metabolic repertoire of fishes. In addition, this gene contains conserved domains and similar tertiary structures in fishes and their putative donor bacteria. Thus, it may function similarly in both groups. Evolutionary analyses indicate that it evolved under purifying selection, further indicating its conserved function. We document the first likely case of HGT of functional gene from prokaryote to fishes. This discovery certifies that HGT can influence vertebrate evolution.

Quantitative gene expression analysis in Caenorhabditis elegans using single molecule RNA FISH.

PubMed

Bolková, Jitka; Lanctôt, Christian

2016-04-01

Advances in fluorescent probe design and synthesis have allowed the uniform in situ labeling of individual RNA molecules. In a technique referred to as single molecule RNA FISH (smRNA FISH), the labeled RNA molecules can be imaged as diffraction-limited spots and counted using image analysis algorithms. Single RNA counting has provided valuable insights into the process of gene regulation. This microscopy-based method has often revealed a high cell-to-cell variability in expression levels, which has in turn led to a growing interest in investigating the biological significance of gene expression noise. Here we describe the application of the smRNA FISH technique to samples of Caenorhabditis elegans, a well-characterized model organism. Copyright © 2015 Elsevier Inc. All rights reserved.

Resveratrol reduces senescence-associated secretory phenotype by SIRT1/NF-κB pathway in gut of the annual fish Nothobranchius guentheri.

PubMed

Liu, Shan; Zheng, Zhaodi; Ji, Shuhua; Liu, Tingting; Hou, Yanhan; Li, Shasha; Li, Guorong

2018-06-13

Senescent cells display a senescence-associated secretory phenotype (SASP), which contributes to aging. Resveratrol, an activator of SIRT1, has anti-aging, anti-inflammatory, anti-oxidant, anti-free radical and other pharmacological effects. The genus of the annual fish Nothobranchius has become an emerging animal model for studying aging. However, the underlying mechanism for resveratrol to delay aging by SASP regulation has not been elucidated in vertebrates. In this study, the annual fish N. guentheri were fed with resveratrol for long-term treatment. The results showed that resveratrol reversed intensive senescence-associated β-galactosidase activity with aging process, down-regulated levels of SASP-associated proinflammatory cytokines IL-8 and TNFα, and up-regulated expression of anti-inflammatory cytokine IL-10 in gut of the fish. Resveratrol increased SIRT1 expression, and inhibited NF-κB by decreasing RelA/p65, Ac-RelA/p65 and p-IκBα levels and by increasing the interaction between SIRT1 and RelA/p65. Moreover, resveratrol reversed the decline of intestinal epithelial cells (IECs) and intestinal stem cells (ISCs) caused by aging in gut of the fish. Together, our results implied that resveratrol inhibited SASP through SIRT1/NF-κB signaling pathway and delayed aging of the annual fish N. guentheri. Copyright © 2018. Published by Elsevier Ltd.

Expression Patterns of CREBs in Oocyte Growth and Maturation of Fish

PubMed Central

Wang, De-Shou; Sudhakumari, Cheni-Chery; Kobayashi, Tohru; Nagahama, Yoshitaka

2015-01-01

In fish, oocyte meiotic maturation is regulated by 17α, 20β-dihydroxy-progesterone through cAMP. To study the role of cAMP response element binding protein (CREB) in meiotic maturation, we cloned and characterized the expression pattern of CREBs from two fish models, the Nile tilapia and catfish. In the Nile tilapia three different CREBs were identified where in CREB1 was found in many tissues including gonads with abundant expression in testis. CREB2, few amino acids shorter than CREB1, was expressed in several tissues with abundant expression in ovary. In addition, a 3’UTR variant form, CREB3 was exclusively found in ovary. During natural 14-day ovarian cycle of the Nile tilapia, CREB1 expression was stable throughout vitellogenesis with a sharp decrease on the day of spawning. In contrast, CREB2 remain unchanged throughout the ovarian cycle, however elevated in 11-day full-grown immature ovarian follicle and after hCG-induction. Interestingly, CREB3 expression was induced three folds on the day of spawning as well as during hCG-induced oocyte maturation. Based on the synergistic expression pattern, CREB1 is likely to control oocyte growth, whereas CREB 2 and 3 contribute to oocyte maturation in tilapia and the latter seems to be critical. In catfish, a single form of CREB showed a maximum expression during spawning phase and hCG-induced maturation both in vivo and in vitro augmented CREB expression. These results suggest that spatial and temporal expression of CREBs seems to be important for final oocyte maturation and may also regulate oocyte growth in fish. PMID:26700177

Hypoxia Stress Modifies Na+/K+-ATPase, H+/K+-ATPase, Na+/NH4+-ATPase, and nkaα1 Isoform Expression in the Brain of Immune-Challenged Air-Breathing Fish

PubMed Central

Peter, MC Subhash; Simi, Satheesan

2017-01-01

Fishes are equipped to sense stressful stimuli and are able to respond to environmental stressor such as hypoxia with varying pattern of stress response. The functional attributes of brain to hypoxia stress in relation to ion transport and its interaction during immune challenge have not yet delineated in fish. We, therefore, explored the pattern of ion transporter functions and messenger RNA (mRNA) expression of α1-subunit isoforms of Na+/K+-ATPase (NKA) in the brain segments, namely, prosencephalon (PC), mesencephalon (MC), and metencephalon (MeC) in an obligate air-breathing fish exposed either to hypoxia stress (30 minutes forced immersion in water) or challenged with zymosan treatment (25-200 ng g−1 for 24 hours) or both. Zymosan that produced nonspecific immune responses evoked differential regulation of NKA, H+/K+-ATPase (HKA), and Na+/NH4+-ATPase (NNA) in the varied brain segments. On the contrary, hypoxia stress that demanded activation of NKA in PC and MeC showed a reversed NKA activity pattern in MeC of immune-challenged fish. A compromised HKA and NNA regulation during hypoxia stress was found in immune-challenged fish, indicating the role of these brain ion transporters to hypoxia stress and immune challenges. The differential mRNA expression of α1-subunit isoforms of NKA, nkaα1a, nkaα1b, and nkaα1c, in hypoxia-stressed brain showed a shift in its expression pattern during hypoxia stress-immune interaction in PC and MC. Evidence is thus presented for the first time that ion transporters such as HKA and NNA along with NKA act as functional brain markers which respond differentially to both hypoxia stress and immune challenges. Taken together, the data further provide evidence for a differential Na+, K+, H+, and NH4+ ion signaling that exists in brain neuronal clusters during hypoxia stress-immune interaction as a result of modified regulations of NKA, HKA, and NNA transporter functions and nkaα1 isoform regulation. PMID:29238219

Hypoxia Stress Modifies Na+/K+-ATPase, H+/K+-ATPase, [Formula: see text], and nkaα1 Isoform Expression in the Brain of Immune-Challenged Air-Breathing Fish.

PubMed

Peter, Mc Subhash; Simi, Satheesan

2017-01-01

Fishes are equipped to sense stressful stimuli and are able to respond to environmental stressor such as hypoxia with varying pattern of stress response. The functional attributes of brain to hypoxia stress in relation to ion transport and its interaction during immune challenge have not yet delineated in fish. We, therefore, explored the pattern of ion transporter functions and messenger RNA (mRNA) expression of α1-subunit isoforms of Na + /K + -ATPase (NKA) in the brain segments, namely, prosencephalon (PC), mesencephalon (MC), and metencephalon (MeC) in an obligate air-breathing fish exposed either to hypoxia stress (30 minutes forced immersion in water) or challenged with zymosan treatment (25-200 ng g -1 for 24 hours) or both. Zymosan that produced nonspecific immune responses evoked differential regulation of NKA, H + /K + -ATPase (HKA), and [Formula: see text] (NNA) in the varied brain segments. On the contrary, hypoxia stress that demanded activation of NKA in PC and MeC showed a reversed NKA activity pattern in MeC of immune-challenged fish. A compromised HKA and NNA regulation during hypoxia stress was found in immune-challenged fish, indicating the role of these brain ion transporters to hypoxia stress and immune challenges. The differential mRNA expression of α1-subunit isoforms of NKA, nkaα1a , nkaα1b , and nkaα1c , in hypoxia-stressed brain showed a shift in its expression pattern during hypoxia stress-immune interaction in PC and MC. Evidence is thus presented for the first time that ion transporters such as HKA and NNA along with NKA act as functional brain markers which respond differentially to both hypoxia stress and immune challenges. Taken together, the data further provide evidence for a differential Na + , K + , H + , and [Formula: see text] ion signaling that exists in brain neuronal clusters during hypoxia stress-immune interaction as a result of modified regulations of NKA, HKA, and NNA transporter functions and nkaα1 isoform regulation.

Chemokine C-C motif ligand 33 is a key regulator of teleost fish barbel development.

PubMed

Zhou, Tao; Li, Ning; Jin, Yulin; Zeng, Qifan; Prabowo, Wendy; Liu, Yang; Tian, Changxu; Bao, Lisui; Liu, Shikai; Yuan, Zihao; Fu, Qiang; Gao, Sen; Gao, Dongya; Dunham, Rex; Shubin, Neil H; Liu, Zhanjiang

2018-05-29

Barbels are important sensory organs in teleosts, reptiles, and amphibians. The majority of ∼4,000 catfish species, such as the channel catfish ( Ictalurus punctatus ), possess abundant whisker-like barbels. However, barbel-less catfish, such as the bottlenose catfish ( Ageneiosus marmoratus ), do exist. Barbeled catfish and barbel-less catfish are ideal natural models for determination of the genomic basis for barbel development. In this work, we generated and annotated the genome sequences of the bottlenose catfish, conducted comparative and subtractive analyses using genome and transcriptome datasets, and identified differentially expressed genes during barbel regeneration. Here, we report that chemokine C-C motif ligand 33 ( ccl33 ), as a key regulator of barbel development and regeneration. It is present in barbeled fish but absent in barbel-less fish. The ccl33 genes are differentially expressed during barbel regeneration in a timing concordant with the timing of barbel regeneration. Knockout of ccl33 genes in the zebrafish ( Danio rerio ) resulted in various phenotypes, including complete loss of barbels, reduced barbel sizes, and curly barbels, suggesting that ccl33 is a key regulator of barbel development. Expression analysis indicated that paralogs of the ccl33 gene have both shared and specific expression patterns, most notably expressed highly in various parts of the head, such as the eye, brain, and mouth areas, supporting its role for barbel development.

Modulation of antioxidant defense and immune response in zebra fish (Danio rerio) using dietary sodium propionate.

PubMed

Safari, Roghieh; Hoseinifar, Seyed Hossein; Kavandi, Morteza

2016-12-01

The present study explores the effect of dietary sodium propionate on mucosal immune response and expression of antioxidant enzyme genes in zebra fish (Danio rerio). Six hundred healthy zebra fish (0.42 ± 0.06 g) supplied, randomly stocked in 12 aquariums and fed on basal diets supplemented with different levels of sodium propionate [0 (control), 5, 10 and 20 g kg -1 ] for 8 weeks. At the end of the feeding trial, mucosal immune parameters (TNF-α, IL-1β, Lyz), antioxidant enzyme (SOD, CAT) as well as heat shock protein 70 (HSP70) gene expression were measured. The results revealed feeding on sodium propionate significantly up-regulated inflammatory response genes (TNF-α, IL-1β, Lyz) in a dose-dependent manner (P < 0.05). However, antioxidant enzyme genes significantly down-regulated in the treated group compared with control (P < 0.05). Also, HSP70 gene expression was higher in the liver of fish fed the basal diet and deceased with elevation of sodium propionate levels in the diet. These results showed beneficial effects of dietary sodium propionate on mucosal immune response as well as the antioxidant defense of zebra fish.

Regulation of Bicarbonate Secretion in Marine Fish Intestine by the Calcium-Sensing Receptor.

PubMed

Gregório, Sílvia F; Fuentes, Juan

2018-04-04

In marine fish, high epithelial intestinal HCO₃ − secretion generates luminal carbonate precipitates of divalent cations that play a key role in water and ion homeostasis. The present study was designed to expose the putative role for calcium and the calcium-sensing receptor (CaSR) in the regulation of HCO₃ − secretion in the intestine of the sea bream ( Sparus aurata L.). Effects on the expression of the CaSR in the intestine were evaluated by qPCR and an increase was observed in the anterior intestine in fed fish compared with unfed fish and with different regions of intestine. CaSR expression reflected intestinal fluid calcium concentration. In addition, anterior intestine tissue was mounted in Ussing chambers to test the putative regulation of HCO₃ − secretion in vitro using the anterior intestine. HCO₃ − secretion was sensitive to varying calcium levels in luminal saline and to calcimimetic compounds known to activate/block the CaSR i.e., R 568 and NPS-2143. Subsequent experiments were performed in intestinal sacs to measure water absorption and the sensitivity of water absorption to varying luminal levels of calcium and calcimimetics were exposed as well. It appears, that CaSR mediates HCO₃ − secretion and water absorption in marine fish as shown by responsiveness to calcium levels and calcimimetic compounds.

Differential expression of largemouth bass (Micropterus salmoides) estrogen receptor isotypes alpha, beta, and gamma by estradiol.

PubMed

Sabo-Attwood, Tara; Kroll, Kevin J; Denslow, Nancy D

2004-04-15

The expression levels of three estrogen receptor (ER) isotypes alpha, beta, and gamma were quantified in female largemouth bass (Micropterus salmoides) (LMB) liver, ovary, brain, and pituitary tissues. ER alpha and beta expression predominated in the liver, while ERs beta and gamma predominated in the other tissues. Temporally in females, ER alpha was highly up-regulated, ER gamma was slightly up-regulated, and ER beta levels remained unchanged in the liver when plasma 17-beta estradiol (E2) and vitellogenin (Vtg) levels were elevated in the spring. In ovarian tissue from these same fish, all three ERs were maximally expressed in the fall, during early oocyte development and prior to peak plasma E2 levels. When males were injected with E2, ER alpha was highly inducible, ER gamma was moderately up-regulated, and ER beta levels were not affected. None of the ER isotypes were induced by E2 in gonadal tissues. These results combined suggest that the ERs themselves are not regulated in the same manner by E2, and furthermore, do not contribute equally to the transcriptional regulation of genes involved in fish reproduction such as Vtg.

Integrated mRNA and microRNA transcriptome analyses reveal regulation of thermal acclimation in Gymnocypris przewalskii: A case study in Tibetan Schizothoracine fish

PubMed Central

Tian, Fei; Zhao, Kai

2017-01-01

Environmental acclimation is important episode in wildlife occupation of the high-altitude Tibetan Plateau (TP). Transcriptome-wide studies on thermal acclimation mechanism in fish species are rarely revealed in Tibetan Plateau fish at high altitude. Thus, we used mRNA and miRNA transcriptome sequencing to investigate regulation of thermal acclimation in larval Tibetan naked carp, Gymnocypris przewalskii. We first remodeled the regulation network of mRNA and miRNA in thermal acclimation, and then identified differential expression of miRNAs and target mRNAs enriched in metabolic and digestive pathways. Interestingly, we identified two candidate genes contributed to normal skeletal development. The altered expression of these gene groups could potentially be associated with the developmental issues of deformity and induced larval death. Our results have three important implications: first, these findings provide strong evidences to support our hypothesis that G. przewalskii possess ability to build heat-tolerance against the controversial issue. Second, this study shows that transcriptional and post-transcriptional regulations are extensively involved in thermal acclimation. Third, the integrated mRNA and microRNA transcriptome analyses provide a large number of valuable genetic resources for future studies on environmental stress response in G. przewalskii and as a case study in Tibetan Schizothoracine fish. PMID:29045433

Transcriptomic variation of locally-infected skin of Epinephelus coioides reveals the mucosal immune mechanism against Cryptocaryon irritans.

PubMed

Hu, Yazhou; Li, Anxing; Xu, Yang; Jiang, Biao; Lu, Geling; Luo, Xiaochun

2017-07-01

Fish skin is the largest immunologically active mucosal organ, providing first-line defense against external pathogens. However, the skin-associated immune mechanisms of fish are still unclear. Cryptocaryon irritans is an obligate ectoparasitic ciliated protozoan that infects almost all marine fish, and is believed to be an excellent pathogen model to study fish mucosal immunity. In this study, a de novo transcriptome assembly of Epinephelus coioides skin post C. irritans tail-infection was performed for the first time using the Illumina HiSeq™ 2500 system. Comparative analyses of infected skin (group Isk) and uninfected skin (group Nsk) from the same challenged fish and control skin (group C) from uninfected control fish were conducted. As a result, a total of 91,082 unigenes with an average length of 2880 base pairs were obtained and among them, 38,704 and 48,617 unigenes were annotated based on homology with matches in the non-redundant and zebrafish database, respectively. Pairwise comparison resulted in 10,115 differentially-expressed genes (DEGs) in the Isk/C group comparison (4,983 up-regulated and 5,132 down-regulated), 2,275 DEGs in the Isk/Nsk group comparison (1,319 up-regulated and 956 down-regulated) and 4,566 DEGs in the Nsk/C group comparison (1,534 up-regulated and 3,032 down-regulated). Seven immune-related categories including 91 differentially-expressed immune genes (86 up-regulated and 5 down-regulated) were scrutinized. Both DEGs and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and immune-related gene expression analysis were used, and both analyses showed that the genes were more significantly altered in the locally-infected skin than in the uninfected skin of the same challenged fish. This suggests the skin's local immune response is important for host defense against this ectoparasite infection. Innate immune molecules, including hepcidin, C-type lectin, transferrin, transferrin receptor protein, serum amyloid A, cathepsin and complement components were significantly up-regulated (fold-change ranged from 3.3 to 12,944) in infected skin compared with control skin. The up-regulation of chemokines and chemokine receptors and activation of the leukocyte transendothelial migration pathway suggested that leucocytes intensively migrated to the local infected sites to mount a local immune defense. Toll-like receptors (TLRs) 1, 2, 5 and 5S were most significantly up-regulated in the infected skin, suggesting that these TLRs may be involved in parasite pathogen-associated molecular pattern (PAMPs) recognition. Up-regulation of the dendritic cell markers CD209 and CD83 and other antigen presentation pathway molecules provided evidence for skin local antigen presentation. Up-regulation of the T cell markers CD4 and CD48, B cell markers CD22 and CD81 and B cell receptor signaling kinase Lyn, showed the presence and population expansion of T/B cells at locally-infected sites, which suggested possible activation of a local specific immune response in the skin. Our results will facilitate in-depth understanding of local immune defense mechanisms in fish skin against ectoparasite infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genotype-specific responses in Atlantic salmon (Salmo salar) subject to dietary fish oil replacement by vegetable oil: a liver transcriptomic analysis.

PubMed

Morais, Sofia; Pratoomyot, Jarunan; Taggart, John B; Bron, James E; Guy, Derrick R; Bell, J Gordon; Tocher, Douglas R

2011-05-20

Expansion of aquaculture is seriously limited by reductions in fish oil (FO) supply for aquafeeds. Terrestrial alternatives such as vegetable oils (VO) have been investigated and recently a strategy combining genetic selection with changes in diet formulations has been proposed to meet growing demands for aquaculture products. This study investigates the influence of genotype on transcriptomic responses to sustainable feeds in Atlantic salmon. A microarray analysis was performed to investigate the liver transcriptome of two family groups selected according to their estimated breeding values (EBVs) for flesh lipid content, 'Lean' or 'Fat', fed diets containing either FO or a VO blend. Diet principally affected metabolism genes, mainly of lipid and carbohydrate, followed by immune response genes. Genotype had a much lower impact on metabolism-related genes and affected mostly signalling pathways. Replacement of dietary FO by VO caused an up-regulation of long-chain polyunsaturated fatty acid biosynthesis, but there was a clear genotype effect as fatty acyl elongase (elovl2) was only up-regulated and desaturases (Δ5 fad and Δ6 fad) showed a higher magnitude of response in Lean fish, which was reflected in liver fatty acid composition. Fatty acid synthase (FAS) was also up-regulated by VO and the effect was independent of genotype. Genetic background of the fish clearly affected regulation of lipid metabolism, as PPARα and PPARβ were down-regulated by the VO diet only in Lean fish, while in Fat salmon SREBP-1 expression was up-regulated by VO. In addition, all three genes had a lower expression in the Lean family group than in the Fat, when fed VO. Differences in muscle adiposity between family groups may have been caused by higher levels of hepatic fatty acid and glycerophospholipid synthesis in the Fat fish, as indicated by the expression of FAS, 1-acyl-sn-glycerol-3-phosphate acyltransferase and lipid phosphate phosphohydrolase 2. This study has identified metabolic pathways and key regulators that may respond differently to alternative plant-based feeds depending on genotype. Further studies are required but data suggest that it will be possible to identify families better adapted to alternative diet formulations that might be appropriate for future genetic selection programmes.

Genotype-specific responses in Atlantic salmon (Salmo salar) subject to dietary fish oil replacement by vegetable oil: a liver transcriptomic analysis

PubMed Central

2011-01-01

Background Expansion of aquaculture is seriously limited by reductions in fish oil (FO) supply for aquafeeds. Terrestrial alternatives such as vegetable oils (VO) have been investigated and recently a strategy combining genetic selection with changes in diet formulations has been proposed to meet growing demands for aquaculture products. This study investigates the influence of genotype on transcriptomic responses to sustainable feeds in Atlantic salmon. Results A microarray analysis was performed to investigate the liver transcriptome of two family groups selected according to their estimated breeding values (EBVs) for flesh lipid content, 'Lean' or 'Fat', fed diets containing either FO or a VO blend. Diet principally affected metabolism genes, mainly of lipid and carbohydrate, followed by immune response genes. Genotype had a much lower impact on metabolism-related genes and affected mostly signalling pathways. Replacement of dietary FO by VO caused an up-regulation of long-chain polyunsaturated fatty acid biosynthesis, but there was a clear genotype effect as fatty acyl elongase (elovl2) was only up-regulated and desaturases (Δ5 fad and Δ6 fad) showed a higher magnitude of response in Lean fish, which was reflected in liver fatty acid composition. Fatty acid synthase (FAS) was also up-regulated by VO and the effect was independent of genotype. Genetic background of the fish clearly affected regulation of lipid metabolism, as PPARα and PPARβ were down-regulated by the VO diet only in Lean fish, while in Fat salmon SREBP-1 expression was up-regulated by VO. In addition, all three genes had a lower expression in the Lean family group than in the Fat, when fed VO. Differences in muscle adiposity between family groups may have been caused by higher levels of hepatic fatty acid and glycerophospholipid synthesis in the Fat fish, as indicated by the expression of FAS, 1-acyl-sn-glycerol-3-phosphate acyltransferase and lipid phosphate phosphohydrolase 2. Conclusions This study has identified metabolic pathways and key regulators that may respond differently to alternative plant-based feeds depending on genotype. Further studies are required but data suggest that it will be possible to identify families better adapted to alternative diet formulations that might be appropriate for future genetic selection programmes. PMID:21599965

Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system.

PubMed

Kim, Minji; Goto, Tsuyoshi; Yu, Rina; Uchida, Kunitoshi; Tominaga, Makoto; Kano, Yuriko; Takahashi, Nobuyuki; Kawada, Teruo

2015-12-17

Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism.

Fish oil intake induces UCP1 upregulation in brown and white adipose tissue via the sympathetic nervous system

PubMed Central

Kim, Minji; Goto, Tsuyoshi; Yu, Rina; Uchida, Kunitoshi; Tominaga, Makoto; Kano, Yuriko; Takahashi, Nobuyuki; Kawada, Teruo

2015-01-01

Brown adipose tissue (BAT) plays a central role in regulating energy homeostasis, and may provide novel strategies for the treatment of human obesity. BAT-mediated thermogenesis is regulated by mitochondrial uncoupling protein 1 (UCP1) in classical brown and ectopic beige adipocytes, and is controlled by sympathetic nervous system (SNS). Previous work indicated that fish oil intake reduces fat accumulation and induces UCP1 expression in BAT; however, the detailed mechanism of this effect remains unclear. In this study, we investigated the effect of fish oil on energy expenditure and the SNS. Fish oil intake increased oxygen consumption and rectal temperature, with concomitant upregulation of UCP1 and the β3 adrenergic receptor (β3AR), two markers of beige adipocytes, in the interscapular BAT and inguinal white adipose tissue (WAT). Additionally, fish oil intake increased the elimination of urinary catecholamines and the noradrenaline (NA) turnover rate in interscapular BAT and inguinal WAT. Furthermore, the effects of fish oil on SNS-mediated energy expenditure were abolished in transient receptor potential vanilloid 1 (TRPV1) knockout mice. In conclusion, fish oil intake can induce UCP1 expression in classical brown and beige adipocytes via the SNS, thereby attenuating fat accumulation and ameliorating lipid metabolism. PMID:26673120

Identification of Zebrafish Fxyd11a Protein that is Highly Expressed in Ion-Transporting Epithelium of the Gill and Skin and its Possible Role in Ion Homeostasis

PubMed Central

Saito, Kaori; Nakamura, Nobuhiro; Ito, Yusuke; Hoshijima, Kazuyuki; Esaki, Masahiro; Zhao, Boqiang; Hirose, Shigehisa

2010-01-01

FXYD proteins, small single-transmembrane proteins, have been proposed to be auxiliary regulatory subunits of Na+–K+-ATPase and have recently been implied in ion osmoregulation of teleost fish. In freshwater (FW) fish, numerous ions are actively taken up through mitochondrion-rich cells (MRCs) of the gill and skin epithelia, using the Na+ electrochemical gradient generated by Na+–K+-ATPase. In the present study, to understand the molecular mechanism for the regulation of Na+–K+-ATPase in MRCs of FW fish, we sought to identify FXYD proteins expressed in MRCs of zebrafish. Reverse-transcriptase PCR studies of adult zebrafish tissues revealed that, out of eight fxyd genes found in zebrafish database, only zebrafish fxyd11 (zfxyd11) mRNA exhibited a gill-specific expression. Double immunofluorescence staining showed that zFxyd11 is abundantly expressed in MRCs rich in Na+–K+-ATPase (NaK-MRCs) but not in those rich in vacuolar-type H+-transporting ATPase. An in situ proximity ligation assay demonstrated its close association with Na+–K+-ATPase in NaK-MRCs. The zfxyd11 mRNA expression was detectable at 1 day postfertilization, and its expression levels in the whole larvae and adult gills were regulated in response to changes in environmental ionic concentrations. Furthermore, knockdown of zFxyd11 resulted in a significant increase in the number of Na+–K+-ATPase–positive cells in the larval skin. These results suggest that zFxyd11 may regulate the transport ability of NaK-MRCs by modulating Na+–K+-ATPase activity, and may be involved in the regulation of body fluid and electrolyte homeostasis. PMID:21423371

Differential regulation of msx genes in the development of the gonopodium, an intromittent organ, and of the "sword," a sexually selected trait of swordtail fishes (Xiphophorus).

PubMed

Zauner, Hans; Begemann, Gerrit; Marí-Beffa, Manuel; Meyer, Axel

2003-01-01

The possession of a conspicuous extension of colored ventral rays of the caudal fin in male fish of swordtails (genus Xiphophorus) is a prominent example for a trait that evolved by sexual selection. To understand the evolutionary history of this so-called sword molecularly, it is of interest to unravel the developmental pathways responsible for extended growth of sword rays during development of swordtail males. We isolated two msx genes and showed that they are differentially regulated during sword outgrowth. During sword growth in juvenile males, as well as during testosterone-induced sword development and fin ray regeneration in the sword after amputation, expression of msxC is markedly up-regulated in the sword forming fin rays. In contrast, msxE/1 is not differentially expressed in ventral and dorsal male fin rays, suggesting a link between the development of male secondary sexual characters in fins and up-regulation of msxC expression. In addition, we showed that msx gene expression patterns differ significantly between Xiphophorus and zebrafish. We also included in our study the gonopodium, a testosterone-dependent anal fin modification that serves as a fertilization organ in males of live-bearing fishes. Our finding that increased levels of msxC expression are associated with the testosterone-induced outgrowth of the gonopodium might suggest either that at least parts of the signaling pathways that pattern the evolutionary older gonopodium have been coopted to evolve a sexually selected innovation such as the sword or that increased msxC expression may be inherent to the growth process of long fin rays in general.

Relevance of Light Spectra to Growth of the Rearing Tiger Puffer Takifugu rubripes

PubMed Central

Kim, Byeong-Hoon; Hur, Sung-Pyo; Hur, Sang-Woo; Lee, Chi-Hoon; Lee, Young-Don

2016-01-01

In fish, light (photoperiod, intensity and spectra) is main regulator in many physiological actions includinggrowth. We investigate the effect of light spectra on the somatic growth and growth-related gene expression in the rearing tiger puffer. Fish was reared under different light spectra (blue, green and red) for 8 weeks. Fish body weight and total length were promoted when reared under green light condition than red light condition. Expression of somatostatins (ss1 and ss2) in brain were showed higher expression under red light condition than green light condition. The ss3 mRNA was observed only higher expression in blue light condition. Expression of growth hormone (gh) in pituitary was detected no different levels between experimental groups. However, the fish of green light condition group was showed more high weight gain and feed efficiency than other light condition groups. Our present results suggest that somatic growth of tiger puffer is induced under green light condition because of inhibiting ss mRNA expression in brain by effect of green wavelength. PMID:27294208

Sequence and Expression Analysis of Interferon Regulatory Factor 10 (IRF10) in Three Diverse Teleost Fish Reveals Its Role in Antiviral Defense

PubMed Central

Xu, Qiaoqing; Jiang, Yousheng; Wangkahart, Eakapol; Zou, Jun; Chang, Mingxian; Yang, Daiqin; Secombes, Chris J.; Nie, Pin; Wang, Tiehui

2016-01-01

Background Interferon regulatory factor (IRF) 10 was first found in birds and is present in the genome of other tetrapods (but not humans and mice), as well as in teleost fish. The functional role of IRF10 in vertebrate immunity is relatively unknown compared to IRF1-9. The target of this research was to clone and characterize the IRF10 genes in three economically important fish species that will facilitate future evaluation of this molecule in fish innate and adaptive immunity. Molecular Characterization of IRF10 in Three Fish Species In the present study, a single IRF10 gene was cloned in grass carp Ctenopharyngodon idella and Asian swamp eel Monopterus albus, and two, named IRF10a and IRF10b, in rainbow trout Oncorhynchus mykiss. The fish IRF10 molecules share highest identities to other vertebrate IRF10s, and have a well conserved DNA binding domain, IRF-associated domain, and an 8 exon/7 intron structure with conserved intron phase. The presence of an upstream ATG or open reading frame (ORF) in the 5’-untranslated region of different fish IRF10 cDNA sequences suggests potential regulation at the translational level, and this has been verified by in vitro transcription/translation experiments of the trout IRF10a cDNA, but would still need to be validated in fish cells. Expression Analysis of IRF10 In Vivo and In Vitro Both trout IRF10 paralogues are highly expressed in thymus, blood and spleen but are relatively low in head kidney and caudal kidney. Trout IRF10b expression is significantly higher than IRF10a in integumentary tissues i.e. gills, scales, skin, intestine, adipose fin and tail fins, suggesting that IRF10b may be more important in mucosal immunity. The expression of both trout IRF10 paralogues is up-regulated by recombinant IFN-γ. The expression of the IRF10 genes is highly induced by Poly I:C in vitro and in vivo, and by viral infection, but is less responsive to peptidoglycan and bacterial infection, suggesting an important role of fish IRF10 in antiviral defense. PMID:26783745

Effects of glucose, insulin and triiodothyroxine on leptin and leptin receptor expression and the effects of leptin on activities of enzymes related to glucose metabolism in grass carp (Ctenopharyngodon idella) hepatocytes.

PubMed

Lu, Rong-Hua; Zhou, Yi; Yuan, Xiao-Chen; Liang, Xu-Fang; Fang, Liu; Bai, Xiao-Li; Wang, Min; Zhao, Yu-Hua

2015-08-01

Leptin is an important regulator of appetite and energy expenditure in mammals, but its role in fish metabolism control is poorly understood. Our previous studies demonstrated that leptin has an effect on the regulation of food intake and energy expenditure as well as lipid metabolism (stimulation of lipolysis and inhibition of adipogenesis) in the grass carp Ctenopharyngodon idella. To further investigate the role of leptin in fish, the effects of glucose, insulin and triiodothyroxine (T3) on the expression levels of leptin and leptin receptor (Lepr) and the effects of leptin on the activities of critical glucose metabolism enzymes in grass carp hepatocytes were evaluated in the present study. Our data indicated that leptin gene expression was induced by glucose in a dose-dependent manner, while Lepr gene expression exhibited a biphasic change. A high dose of insulin (100 ng/mL) significantly up-regulated the expression of leptin and Lepr. Leptin expression was markedly up-regulated by a low concentration of T3 but inhibited by a high concentration of T3. T3 up-regulated Lepr expression in a dose-dependent manner. Together, these data suggest that leptin had a close relationship with three factors (glucose, insulin and T3) and might participate in the regulation of glucose metabolism in grass carp. In addition, we also found that leptin affected the activities of key enzymes that are involved in glucose metabolism, which might be mediated by insulin receptor substrate-phosphoinositol 3-kinase signaling.

Zearalenone (ZEN) and Its Influence on Regulation of Gene Expression in Carp (Cyprinus carpio L.) Liver Tissue

PubMed Central

Pietsch, Constanze

2017-01-01

Zearalenone (ZEN) is a frequently-occurring mycotoxin in both animal and fish feeds. In order to characterize its effects on carp, three groups of fish were fed for 28 days with feeds contaminated with three different levels of ZEN (low: 332 µg kg−1, medium: 621 µg kg−1, and high: 797 µg kg−1 feed). The reversibility of the effects of ZEN was assessed by feeding all of the groups with uncontaminated feed for a further 14 days. Gene expression of immune genes in the liver tissue of the fish was analysed, revealing reduced expressions of immune, antioxidative, and estrogen-related genes after the fish had been exposed to ZEN. However, the expression of vacuole-type H+ ATPase increased substantially with ZEN exposure, thus supporting the previously-reported sensitivity of lysosomal functions to ZEN. Feeding the fish with a ZEN-free diet for a further two weeks changed the effects of ZEN on the expression of some genes, including the expressions of the cytokines IL-1β, IL-8, IL-10, and arginase 2, which were not influenced after four weeks of treatment, but showed lower values after the recovery phase in fish previously treated with ZEN compared with the control group. In summary, this study confirmed the broad effects of ZEN on different essential functions in carp and suggests that the current maximum allowable levels in compound feed are too high to prevent damage to fish. PMID:28914814

Zearalenone (ZEN) and Its Influence on Regulation of Gene Expression in Carp (Cyprinus carpio L.) Liver Tissue.

PubMed

Pietsch, Constanze

2017-09-15

Zearalenone (ZEN) is a frequently-occurring mycotoxin in both animal and fish feeds. In order to characterize its effects on carp, three groups of fish were fed for 28 days with feeds contaminated with three different levels of ZEN (low: 332 µg kg -1 , medium: 621 µg kg -1 , and high: 797 µg kg -1 feed). The reversibility of the effects of ZEN was assessed by feeding all of the groups with uncontaminated feed for a further 14 days. Gene expression of immune genes in the liver tissue of the fish was analysed, revealing reduced expressions of immune, antioxidative, and estrogen-related genes after the fish had been exposed to ZEN. However, the expression of vacuole-type H⁺ ATPase increased substantially with ZEN exposure, thus supporting the previously-reported sensitivity of lysosomal functions to ZEN. Feeding the fish with a ZEN-free diet for a further two weeks changed the effects of ZEN on the expression of some genes, including the expressions of the cytokines IL-1β, IL-8, IL-10, and arginase 2, which were not influenced after four weeks of treatment, but showed lower values after the recovery phase in fish previously treated with ZEN compared with the control group. In summary, this study confirmed the broad effects of ZEN on different essential functions in carp and suggests that the current maximum allowable levels in compound feed are too high to prevent damage to fish.

Hypothalamic Integration of Metabolic, Endocrine, and Circadian Signals in Fish: Involvement in the Control of Food Intake

PubMed Central

Delgado, María J.; Cerdá-Reverter, José M.; Soengas, José L.

2017-01-01

The regulation of food intake in fish is a complex process carried out through several different mechanisms in the central nervous system (CNS) with hypothalamus being the main regulatory center. As in mammals, a complex hypothalamic circuit including two populations of neurons: one co-expressing neuropeptide Y (NPY) and Agouti-related peptide (AgRP) and the second one population co-expressing pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) is involved in the integration of information relating to food intake control. The production and release of these peptides control food intake, and the production results from the integration of information of different nature such as levels of nutrients and hormones as well as circadian signals. The present review summarizes the knowledge and recent findings about the presence and functioning of these mechanisms in fish and their differences vs. the known mammalian model. PMID:28694769

Sequence and Expression Analysis of Interferon Regulatory Factor 10 (IRF10) in Three Diverse Teleost Fish Reveals Its Role in Antiviral Defense.

PubMed

Xu, Qiaoqing; Jiang, Yousheng; Wangkahart, Eakapol; Zou, Jun; Chang, Mingxian; Yang, Daiqin; Secombes, Chris J; Nie, Pin; Wang, Tiehui

2016-01-01

Interferon regulatory factor (IRF) 10 was first found in birds and is present in the genome of other tetrapods (but not humans and mice), as well as in teleost fish. The functional role of IRF10 in vertebrate immunity is relatively unknown compared to IRF1-9. The target of this research was to clone and characterize the IRF10 genes in three economically important fish species that will facilitate future evaluation of this molecule in fish innate and adaptive immunity. In the present study, a single IRF10 gene was cloned in grass carp Ctenopharyngodon idella and Asian swamp eel Monopterus albus, and two, named IRF10a and IRF10b, in rainbow trout Oncorhynchus mykiss. The fish IRF10 molecules share highest identities to other vertebrate IRF10s, and have a well conserved DNA binding domain, IRF-associated domain, and an 8 exon/7 intron structure with conserved intron phase. The presence of an upstream ATG or open reading frame (ORF) in the 5'-untranslated region of different fish IRF10 cDNA sequences suggests potential regulation at the translational level, and this has been verified by in vitro transcription/translation experiments of the trout IRF10a cDNA, but would still need to be validated in fish cells. Both trout IRF10 paralogues are highly expressed in thymus, blood and spleen but are relatively low in head kidney and caudal kidney. Trout IRF10b expression is significantly higher than IRF10a in integumentary tissues i.e. gills, scales, skin, intestine, adipose fin and tail fins, suggesting that IRF10b may be more important in mucosal immunity. The expression of both trout IRF10 paralogues is up-regulated by recombinant IFN-γ. The expression of the IRF10 genes is highly induced by Poly I:C in vitro and in vivo, and by viral infection, but is less responsive to peptidoglycan and bacterial infection, suggesting an important role of fish IRF10 in antiviral defense.

Two Virus-Induced MicroRNAs Known Only from Teleost Fishes Are Orthologues of MicroRNAs Involved in Cell Cycle Control in Humans

PubMed Central

Schyth, Brian Dall; Bela-ong, Dennis Berbulla; Jalali, Seyed Amir Hossein; Kristensen, Lasse Bøgelund Juel; Einer-Jensen, Katja; Pedersen, Finn Skou; Lorenzen, Niels

2015-01-01

MicroRNAs (miRNAs) are ~22 base pair-long non-coding RNAs which regulate gene expression in the cytoplasm of eukaryotic cells by binding to specific target regions in mRNAs to mediate transcriptional blocking or mRNA cleavage. Through their fundamental roles in cellular pathways, gene regulation mediated by miRNAs has been shown to be involved in almost all biological phenomena, including development, metabolism, cell cycle, tumor formation, and host-pathogen interactions. To address the latter in a primitive vertebrate host, we here used an array platform to analyze the miRNA response in rainbow trout (Oncorhynchus mykiss) following inoculation with the virulent fish rhabdovirus Viral hemorrhagic septicaemia virus. Two clustered miRNAs, miR-462 and miR-731 (herein referred to as miR-462 cluster), described only in teleost fishes, were found to be strongly upregulated, indicating their involvement in fish-virus interactions. We searched for homologues of the two teleost miRNAs in other vertebrate species and investigated whether findings related to ours have been reported for these homologues. Gene synteny analysis along with gene sequence conservation suggested that the teleost fish miR-462 and miR-731 had evolved from the ancestral miR-191 and miR-425 (herein called miR-191 cluster), respectively. Whereas the miR-462 cluster locus is found between two protein-coding genes (intergenic) in teleost fish genomes, the miR-191 cluster locus is found within an intron of a protein-coding gene (intragenic) in the human genome. Interferon (IFN)-inducible and immune-related promoter elements found upstream of the teleost miR-462 cluster locus suggested roles in immune responses to viral pathogens in fish, while in humans, the miR-191 cluster functionally associated with cell cycle regulation. Stimulation of fish cell cultures with the IFN inducer poly I:C accordingly upregulated the expression of miR-462 and miR-731, while no stimulatory effect on miR-191 and miR-425 expression was observed in human cell lines. Despite high sequence conservation, evolution has thus resulted in different regulation and presumably also different functional roles of these orthologous miRNA clusters in different vertebrate lineages. PMID:26207374

Cloning, distribution and effects of fasting status of melanocortin 4 receptor (MC4R) in Schizothorax prenanti.

PubMed

Wei, Rongbin; Yuan, Dengyue; Zhou, Chaowei; Wang, Tao; Lin, Fangjun; Chen, Hu; Wu, Hongwei; Xin, Zhiming; Yang, Shiyong; Chen, Defang; Wang, Yan; Liu, Ju; Gao, Yundi; Li, Zhiqiong

2013-12-10

Melanocortin 4 receptor (MC4R) has an important role in the regulation of energy homeostasis in both mammals and fish. In this study, MC4R was characterized in S. prenanti (Schizothorax prenanti) and designated as SpMC4R. SpMC4R cDNA is composed of 1004 nucleotides with a 978 nucleotide open reading frame encoding a protein of 326 amino acids. The SpMC4R contained predicted regions that were structural features of MCR subtypes of vertebrates. In addition, phylogenetic analyses suggested that S. prenanti MC4R was closely related to fish MC4Rs. The SpMC4R mRNA was detected in embryos at developmental stages. Further, its mRNA was detectable in unfertilized eggs. Using real-time RT-PCR, MC4R is widely expressed, with highest levels of expression in brain and ovary. An experiment was conducted to determine the expression profile of MC4R during short-term and long-term fasting of the brain. The expression level of MC4R in unfed fish was significantly increased at 6, 9 and 24h post-fasting (hpf) and 14days fasting than in fed fish, this suggests that MC4R is conserved peptide that might be involved in the regulation of food intake and other physiological function in S. prenanti. © 2013.

Detection of rearrangements and transcriptional up-regulation of ALK in FFPE lung cancer specimens using a novel, sensitive, quantitative reverse transcription polymerase chain reaction assay.

PubMed

Gruber, Kim; Horn, Heike; Kalla, Jörg; Fritz, Peter; Rosenwald, Andreas; Kohlhäufl, Martin; Friedel, Godehard; Schwab, Matthias; Ott, German; Kalla, Claudia

2014-03-01

The approved dual-color fluorescence in situ hybridization (FISH) test for the detection of anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements in non-small-cell lung cancer (NSCLC) is complex and represents a low-throughput assay difficult to use in daily diagnostic practice. We devised a sensitive and robust routine diagnostic test for the detection of rearrangements and transcriptional up-regulation of ALK. We developed a quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay adapted to RNA isolated from routine formalin-fixed, paraffin-embedded material and applied it to 652 NSCLC specimens. The reliability of this technique to detect ALK dysregulation was shown by comparison with FISH and immunohistochemistry. qRT-PCR analysis detected unbalanced ALK expression indicative of a gene rearrangement in 24 (4.6%) and full-length ALK transcript expression in six (1.1%) of 523 interpretable tumors. Among 182 tumors simultaneously analyzed by FISH and qRT-PCR, the latter accurately typed 97% of 19 rearranged and 158 nonrearranged tumors and identified ALK deregulation in two cases with insufficient FISH. Six tumors expressing full-length ALK transcripts did not show rearrangements of the gene. Immunohistochemistry detected ALK protein overexpression in tumors with gene fusions and transcriptional up-regulation, but did not distinguish between the two. One case with full-length ALK expression carried a heterozygous point mutation (S1220Y) within the kinase domain potentially interfering with kinase activity and/or inhibitor binding. Our qRT-PCR assay reliably identifies and distinguishes ALK rearrangements and full-length transcript expression in formalin-fixed, paraffin-embedded material. It is an easy-to-perform, cost-effective, and high-throughput tool for the diagnosis of ALK activation. The expression of full-length ALK transcripts may be relevant for ALK inhibitor therapy in NSCLC.

Glucose metabolism and gene expression in juvenile zebrafish (Danio rerio) challenged with a high carbohydrate diet: effects of an acute glucose stimulus during late embryonic life.

PubMed

Rocha, Filipa; Dias, Jorge; Engrola, Sofia; Gavaia, Paulo; Geurden, Inge; Dinis, Maria Teresa; Panserat, Stephane

2015-02-14

Knowledge on the role of early nutritional stimuli as triggers of metabolic pathways in fish is extremely scarce. The objective of the present study was to assess the long-term effects of glucose injection in the yolk (early stimulus) on carbohydrate metabolism and gene regulation in zebrafish juveniles challenged with a high-carbohydrate low-protein (HC) diet. Eggs were microinjected at 1 d post-fertilisation (dpf) with either glucose (2 M) or saline solutions. Up to 25 dpf, fish were fed a low-carbohydrate high-protein (LC) control diet, which was followed by a challenge with the HC diet. Survival and growth of 35 dpf juveniles were not affected by injection or the HC diet. Glucose stimulus induced some long-term metabolic changes in the juveniles, as shown by the altered expression of genes involved in glucose metabolism. On glycolysis, the expression levels of hexokinase 1 (HK1) and phosphofructokinase-6 (6PFK) were up-regulated in the visceral and muscle tissues, respectively, of juveniles exposed to the glucose stimulus, indicating a possible improvement in glucose oxidation. On gluconeogenesis, the inhibition of the expression levels of PEPCK in fish injected with glucose suggested lower production of hepatic glucose. Unexpectedly, fructose-1,6-bisphosphatase (FBP) expression was induced and 6PFK expression reduced by glucose stimulus, leaving the possibility of a specific regulation of the FBP-6PFK metabolic cycle. Glucose metabolism in juveniles was estimated using a [¹⁴C]glucose tracer; fish previously exposed to the stimulus showed lower retention of [¹⁴C]glucose in visceral tissue (but not in muscle tissue) and, accordingly, higher glucose catabolism, in comparison with the saline group. Globally, our data suggest that glucose stimulus at embryo stage has the potential to alter particular steps of glucose metabolism in zebrafish juveniles.

High-fat diet reduces local myostatin-1 paralog expression and alters skeletal muscle lipid content in rainbow trout, Oncorhynchus mykiss

PubMed Central

Galt, Nicholas J.; Froehlich, Jacob Michael; Meyer, Ben M.; Barrows, Frederic T.; Biga, Peggy R.

2014-01-01

Muscle growth is an energetically demanding process that is reliant on intramuscular fatty acid depots in most fishes. The complex mechanisms regulating this growth and lipid metabolism are of great interest for human health and aquaculture applications. It is well established that the skeletal muscle chalone, myostatin, plays a role in lipid metabolism and adipogenesis in mammals; however, this function has not been fully assessed in fishes. We therefore examined the interaction between dietary lipid levels and myostatin expression in rainbow trout (Oncorhynchus mykiss). Five-weeks of high-fat (HFD; 25% lipid) dietary intake increased white muscle lipid content, and decreased circulating glucose levels and hepatosomatic index when compared to low-fat diet (LFD; 10% lipid) intake. In addition HFD intake reduced myostatin-1a and -1b expression in white muscle and myostatin-1b expression in brain tissue. Characterization of the myostatin-1a, -1b, and -2a promoters revealed putative binding sites for a subset of transcription factors associated with lipid metabolism. Taken together, these data suggest that HFD may regulate myostatin expression through cis-regulatory elements sensitive to increased lipid intake. Further, these findings provide a framework for future investigations of mechanisms describing the relationships between myostatin and lipid metabolism in fish. PMID:24264425

Dietary fish oil regulates gene expression of cholesterol and bile acid transporters in mice.

PubMed

Kamisako, Toshinori; Tanaka, Yuji; Ikeda, Takanori; Yamamoto, Kazuo; Ogawa, Hiroshi

2012-03-01

  Fish oil rich in n-3 polyunsaturated fatty acids is known to affect hepatic lipid metabolism. Several studies have demonstrated that fish oil may affect the bile acid metabolism as well as lipid metabolism, whereas only scarce data are available. The aim of this study was to investigate the effect of fish oil on the gene expression of the transporters and enzymes related to bile acid as well as lipid metabolism in the liver and small intestine.   Seven-week old male C57BL/6 mice were fed diets enriched in 10% soybean oil or 10% fish oil for 4 weeks. After 4 weeks, blood, liver and small intestine were obtained.   Hepatic mRNA expression of lipids (Abcg5/8, multidrug resistance gene product 2) and bile acids transporters (bile salt export pump, multidrug resistance associated protein 2 and 3, organic solute transporter α) was induced in fish oil-fed mice. Hepatic Cyp8b1, Cyp27a1 and bile acid CoA : amino acid N-acyltransferase were increased in fish oil-fed mice compared with soybean-oil fed mice. Besides, intestinal cholesterol (Abcg5/8) and bile acid transporters (multidrug resistance associated protein 2 and organic solute transporter α) were induced in fish oil-fed mice.   Fish oil induced the expression of cholesterol and bile acid transporters not only in liver but in intestine. The upregulation of Abcg5/g8 by fish oil is caused by an increase in cellular 27-HOC through Cyp27a1 induction. The hepatic induction of bile acid synthesis through Cyp27a1 may upregulate expression of bile acid transporters in both organs. © 2012 The Japan Society of Hepatology.

Neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) in winter skate (Raja ocellata): cDNA cloning, tissue distribution and mRNA expression responses to fasting.

PubMed

MacDonald, Erin; Volkoff, Hélène

2009-04-01

cDNAs encoding for neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and cholecystokinin (CCK) were cloned in an elasmobranch fish, the winter skate. mRNA tissue distribution was examined for the three peptides as well as the effects of two weeks of fasting on their expression. Skate NPY, CART and CCK sequences display similarities with sequences for teleost fish but in general the degree of identity is relatively low (50%). All three peptides are present in brain and in several peripheral tissues, including gut and gonads. Within the brain, the three peptides are expressed in the hypothalamus, telencephalon, optic tectum and cerebellum. Two weeks of fasting induced an increase in telencephalon NPY and an increase in CCK in the gut but had no effects on hypothalamic NPY, CART and CCK, or on telencephalon CART. Our results provide basis for further investigation into the regulation of feeding in winter skate.

Proline with or without hydroxyproline influences collagen concentration and regulates prolyl 4-hydroxylase α (I) gene expression in juvenile turbo ( Scophthalmus maximus L.)

NASA Astrophysics Data System (ADS)

Zhang, Kaikai; Mai, Kangsen; Xu, Wei; Zhou, Huihui; Liufu, Zhiguo; Zhang, Yanjiao; Peng, Mo; Ai, Qinghui

2015-06-01

This study was conducted to investigate the effect of dietary proline (Pro), and Pro and hydroxyproline (Hyp) in combination on the growth performance, total Hyp and collagen concentrations of tissues, and prolyl 4-hydroxylase α(I) (P4H α(I)) gene expression in juvenile turbot feeding high plant protein diets. A diet containing 50% crude protein and 12% crude lipid was formulated as the basal and control, on which other two protein and lipid contents identical experimental diets were formulated by supplementing the basal with either 0.75% Pro (Pro-0.75) or 0.75% Pro and 0.75% Hyp (Pro+Hyp). Four groups of fish in indoor seawater recirculating systems, 35 individuals each, were fed twice a day to apparent satiation for 10 weeks. The results showed that dietary Pro and Hyp supplementation had no significant effect on growth performance and feed utilization of juvenile turbot (P > 0.05). Total Hyp and collagen concentrations in muscle were significantly increased when dietary Pro and Hyp increased (P <0.05), and fish fed diet Pro+Hyp showed significantly higher free Hyp content in plasma than those fed other diets (P <0.05). The expression of P4H a(I) gene in liver and muscle was significantly up regulated in fish fed diet Pro-0.75 in comparison with control (P <0.05); however the gene was significantly down regulated in fish fed diet Pro+Hyp in muscle in comparison with fish fed diet Pro-0.75 (P <0.05). It can be concluded that supplement of crystal L-Pro and L-Hyp to high plant protein diets did not show positive effects on growth performance of juvenile turbot, but enhanced total collagen concentrations in muscle.

Molecular identification and characterization of haptoglobin in teleosts revealed an important role on fish viral infections.

PubMed

Cordero, Héctor; Li, Chang Hong; Chaves-Pozo, Elena; Esteban, María Ángeles; Cuesta, Alberto

2017-11-01

Haptoglobin (Hp) molecule has been cloned and characterized in two marine teleosts (gilthead seabream and European sea bass), obtaining putative proteins of 319 residues encoded by an ORF of 960 bp in both species. However, the matrix of similarity revealed low identities among bony fish species 78.9% (seabream-sea bass), 43% (seabream/seabass-zebrafish) and lower than 20% with sharks and human. The protein sequences showed a signal peptide from the position 1 to 23, a trypsin domain from 47 to 297, and several predicted disulfide bridges and glycosylation sites. The expression of hp transcript levels during ontogeny showed a progressive increase of expression in seabream whilst remained almost unaltered in sea bass. By tissues, this gene was found constitutively expressed with the highest levels on liver in both species. The main results on hp transcript levels showed the up-regulation in gilthead seabream suffering from naturally occurring lymphocystis disease; and the down-regulation and up-regulation after nodavirus infection in the resistant gilthead seabream and the susceptible European sea bass, respectively. These findings demonstrate for the first time an important role of haptoglobin against viral infections, operating differently in two of the most important marine farmed fish species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in expression of appetite-regulating hormones in the cunner (Tautogolabrus adspersus) during short-term fasting and winter torpor.

PubMed

Babichuk, Nicole A; Volkoff, Hélène

2013-08-15

Feeding in vertebrates is controlled by a number of appetite stimulating (orexigenic, e.g., orexin and neuropeptide Y, NPY) and appetite suppressing (anorexigenic, e.g., cholecystokinin, CCK and cocaine- and amphetamine-regulated transcript, CART) hormones. Cunners (Tautogolabrus adspersus) survive the winter in shallow coastal waters by entering a torpor-like state, during which they forgo feeding. In order to better understand the mechanisms regulating appetite/fasting in these fish, quantitative real-time PCR was used to measure transcript expression levels of four appetite-regulating hormones: NPY, CART, orexin and CCK in the forebrain (hypothalamus and telencephalon) and CCK in the gut of fed, short-term summer fasted, and natural winter torpor cunners. Summer fasting induced a decrease in hypothalamic orexin levels and telencephalon NPY, CART and CCK mRNA levels. All brain hormone mRNA levels decreased during natural torpor as compared to fed summer fish. In the gut, CCK expression levels decreased during summer fasting. These results indicate that, in cunner, orexin, NPY, CART and CCK may play a role in appetite regulation and might mediate different physiological responses to short-term summer fasting and torpor-induced long-term fasting. © 2013.

Global analysis of gene expression in mineralizing fish vertebra-derived cell lines: new insights into anti-mineralogenic effect of vanadate

PubMed Central

2011-01-01

Background Fish has been deemed suitable to study the complex mechanisms of vertebrate skeletogenesis and gilthead seabream (Sparus aurata), a marine teleost with acellular bone, has been successfully used in recent years to study the function and regulation of bone and cartilage related genes during development and in adult animals. Tools recently developed for gilthead seabream, e.g. mineralogenic cell lines and a 4 × 44K Agilent oligo-array, were used to identify molecular determinants of in vitro mineralization and genes involved in anti-mineralogenic action of vanadate. Results Global analysis of gene expression identified 4,223 and 4,147 genes differentially expressed (fold change - FC > 1.5) during in vitro mineralization of VSa13 (pre-chondrocyte) and VSa16 (pre-osteoblast) cells, respectively. Comparative analysis indicated that nearly 45% of these genes are common to both cell lines and gene ontology (GO) classification is also similar for both cell types. Up-regulated genes (FC > 10) were mainly associated with transport, matrix/membrane, metabolism and signaling, while down-regulated genes were mainly associated with metabolism, calcium binding, transport and signaling. Analysis of gene expression in proliferative and mineralizing cells exposed to vanadate revealed 1,779 and 1,136 differentially expressed genes, respectively. Of these genes, 67 exhibited reverse patterns of expression upon vanadate treatment during proliferation or mineralization. Conclusions Comparative analysis of expression data from fish and data available in the literature for mammalian cell systems (bone-derived cells undergoing differentiation) indicate that the same type of genes, and in some cases the same orthologs, are involved in mechanisms of in vitro mineralization, suggesting their conservation throughout vertebrate evolution and across cell types. Array technology also allowed identification of genes differentially expressed upon exposure of fish cell lines to vanadate and likely involved in its anti-mineralogenic activity. Many were found to be unknown or they were never associated to bone homeostasis previously, thus providing a set of potential candidates whose study will likely bring insights into the complex mechanisms of tissue mineralization and bone formation. PMID:21668972

Interaction between dietary lipids and gut microbiota regulates hepatic cholesterol metabolism.

PubMed

Caesar, Robert; Nygren, Heli; Orešič, Matej; Bäckhed, Fredrik

2016-03-01

The gut microbiota influences many aspects of host metabolism. We have previously shown that the presence of a gut microbiota remodels lipid composition. Here we investigated how interaction between gut microbiota and dietary lipids regulates lipid composition in the liver and plasma, and gene expression in the liver. Germ-free and conventionally raised mice were fed a lard or fish oil diet for 11 weeks. We performed lipidomics analysis of the liver and serum and microarray analysis of the liver. As expected, most of the variation in the lipidomics dataset was induced by the diet, and abundance of most lipid classes differed between mice fed lard and fish oil. However, the gut microbiota also affected lipid composition. The gut microbiota increased hepatic levels of cholesterol and cholesteryl esters in mice fed lard, but not in mice fed fish oil. Serum levels of cholesterol and cholesteryl esters were not affected by the gut microbiota. Genes encoding enzymes involved in cholesterol biosynthesis were downregulated by the gut microbiota in mice fed lard and were expressed at a low level in mice fed fish oil independent of microbial status. In summary, we show that gut microbiota-induced regulation of hepatic cholesterol metabolism is dependent on dietary lipid composition. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

The antiviral defense mechanisms in mandarin fish induced by DNA vaccination against a rhabdovirus.

PubMed

Chen, Zhong-Yuan; Lei, Xiao-Ying; Zhang, Qi-Ya

2012-06-15

Plasmid DNAs containing Siniperca chuatsi rhabdovirus (SCRV) glycoprotein gene (pcDNA-G) and nucleoprotein gene (pcDNA-N) were constructed, and used to determine the antiviral immune response elicited by DNA vaccination in mandarin fish. In vitro and in vivo expression of the plasmid constructs was confirmed in transfected cells and muscle tissues of vaccinated fish by Western blot, indirect immunofluorescence or RT-PCR analysis. Fish injected with pcDNA-G exhibited protective effect against SCRV challenge with a relative percent survival (RPS) of 77.5%, but no significant protection (RPS of 2.5%) was observed in fish vaccinated with pcDNA-N. Immunohistochemical analysis showed that vaccination with pcDNA-G decreased histological lesions and suppressed the virus replication in fish target organs, e.g. kidney, liver, spleen, gill and heart. Transcriptional analysis further revealed that the expression levels of type I IFN system genes including interferon regulation factor-7 (IRF-7) gene, myxovirus resistance (Mx) gene and virus inhibitory protein (Viperin) gene were strongly up-regulated after injection with pcDNA-G, whereas the level of transcription of immunoglobulin M (IgM) gene did not show a statistically significant change. These results reveal that type I IFN antiviral immune response is rapidly triggered by the plasmid DNA containing rhabdovirus glycoprotein gene in fish, which offers an explanation of molecular mechanisms for DNA vaccination inducing mandarin fish resist to SCRV disease. Copyright © 2011 Elsevier B.V. All rights reserved.

Transgenic medaka fish as models to analyze bone homeostasis under micro-gravity conditions in vivo

NASA Astrophysics Data System (ADS)

Winkler, C.; Wagner, T.; Renn, J.; Goerlich, R.; Schartl, M.

Long-term space flight and microgravity results in bone loss that can be explained by reduced activity of bone-forming osteoblast cells and/or an increase in activity of bone resorbing osteoclast cells. Osteoprotegerin (OPG), a secreted protein of 401 amino acids, has been shown to regulate the balance between osteoblast and osteoclast formation and thereby warrants constant bone mass under normal gravitational conditions. Consistent with this, earlier reports using transgenic mice have shown that increased activation of OPG leads to exc essive bone formation (osteopetrosis), while inactivation of OPG leads to bone loss (osteoporosis). Importantly, it has recently been reported that expression of murine OPG is regulated by vector averaged gravity (Kanematsu et al., 2002, Bone 30, p553). The small bony fish medaka (Oryzias latipes ) has attracted increasing attention as genetic model system to study developmental and pathological processes. To analyze the molecular mechanisms of bone formation in this small vertebrate, we have isolated two related genes, opr-1 and opr -2, from medaka. Our phylogenetic analysis revealed that both genes originated from a common ancestor by fish-specific gene duplication and represent the orthologs of the mammalian OPG gene. Both opr genes are differentially expressed during embryonic and larval development, in adult tissues and in cultured primary osteoblast cells. We have characterized their promoter regions and identified consensus binding sites for transcription factors of the bone-morphogenetic-protein (BMP) p thway and for core-binding-factor-1Aa (cbfa1). Cbfa1 has been shown to be the key regulator of OPG expression during several steps of osteoblast differentiation in mammals. This opens the possibility that the mechanisms controlling bone formation in teleost fish and higher vertebrates are regulated by related mechanisms. We are currently generating transgenic medakafish expressing a GFP reporter gene under control of the teleost OPG promoter in order to visualize osteoblast activity in a living organism under different gravity conditions. This work is supported by the German Aerospace Center, DLR.

Season-dependent effects of photoperiod and temperature on circadian rhythm of arylalkylamine N-acetyltransferase2 gene expression in pineal organ of an air-breathing catfish, Clarias gariepinus.

PubMed

Singh, Kshetrimayum Manisana; Saha, Saurav; Gupta, Braj Bansh Prasad

2017-08-01

Arylalkylamine N-acetyltransferase (AANAT) activity, aanat gene expression and melatonin production have been reported to exhibit prominent circadian rhythm in the pineal organ of most species of fish. Three types of aanat genes are expressed in fish, but the fish pineal organ predominantly expresses aanat2 gene. Increase and decrease in daylength is invariably associated with increase and decrease in temperature, respectively. But so far no attempt has been made to delineate the role of photoperiod and temperature in regulation of the circadian rhythm of aanat2 gene expression in the pineal organ of any fish with special reference to seasons. Therefore, we studied effects of various lighting regimes (12L-12D, 16L-8D, 8L-16D, LL and DD) at a constant temperature (25°C) and effects of different temperatures (15°, 25° and 35°C) under a common photoperiod 12L-12D on circadian rhythm of aanat2 gene expression in the pineal organ of Clarias gariepinus during summer and winter seasons. Aanat2 gene expression in fish pineal organ was studied by measuring aanat2 mRNA levels using Real-Time PCR. Our findings indicate that the pineal organ of C. gariepinus exhibits a prominent circadian rhythm of aanat2 gene expression irrespective of photoperiods, temperatures and seasons, and the circadian rhythm of aanat2 gene expression responds differently to different photoperiods and temperatures in a season-dependent manner. Existence of circadian rhythm of aanat2 gene expression in pineal organs maintained in vitro under 12L-12D and DD conditions as well as a free running rhythm of the gene expression in pineal organ of the fish maintained under LL and DD conditions suggest that the fish pineal organ possesses an endogenous circadian oscillator, which is entrained by light-dark cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

Fish Oil Ameliorates High-Fat Diet Induced Male Mouse Reproductive Dysfunction via Modifying the Rhythmic Expression of Testosterone Synthesis Related Genes.

PubMed

Wang, Hualin; Cai, Yazheng; Shao, Yang; Zhang, Xifeng; Li, Na; Zhang, Hongyu; Liu, Zhiguo

2018-04-29

The present study aims to investigate the protective effects of ω-3 polyunsaturated fatty acids (ω-3PUFAs) against high-fat diet induced male mouse reproductive dysfunction and to explore circadian regulation mechanisms. Male C57BL/6 mice were randomly divided into three groups and fed a normal chow diet (control group, CON), a high-fat diet (HFD group) or a HFD supplemented with fish oil (FO group) for 12 weeks. After 12 weeks of feeding, the body weight and the ratio of perinephric and epididymal fat weight to body weight were significantly higher in the HFD group compared with the CON group. The supplement of fish oil rich in ω-3PUFAs only slightly reduced the HFD-induced obesity but remarkably ameliorated HFD-induced dyslipidemia, sexual hormones disorder, testicle lesions and germ cell apoptosis. Fish oil supplementation restored the expression of steroid synthesis associated genes in HFD fed mouse and flattened the HFD-induced oscillations in circadian genes' expression. Fish oil supplementation prevented HFD-induced male mouse reproductive dysfunction and modified the rhythmic expression of testosterone synthesis related genes.

Effects of hypoxia on ionic regulation, glycogen utilization and antioxidative ability in the gills and liver of the aquatic air-breathing fish Trichogaster microlepis.

PubMed

Huang, Chun-Yen; Lin, Hui-Chen; Lin, Cheng-Huang

2015-01-01

We examined the hypothesis that Trichogaster microlepis, a fish with an accessory air-breathing organ, uses a compensatory strategy involving changes in both behavior and protein levels to enhance its gas exchange ability. This compensatory strategy enables the gill ion-regulatory metabolism to maintain homeostasis during exposure to hypoxia. The present study aimed to determine whether ionic regulation, glycogen utilization and antioxidant activity differ in terms of expression under hypoxic stresses; fish were sampled after being subjected to 3 or 12h of hypoxia and 12h of recovery under normoxia. The air-breathing behavior of the fish increased under hypoxia. No morphological modification of the gills was observed. The expression of carbonic anhydrase II did not vary among the treatments. The Na(+)/K(+)-ATPase enzyme activity did not decrease, but increases in Na(+)/K(+)-ATPase protein expression and ionocyte levels were observed. The glycogen utilization increased under hypoxia as measured by glycogen phosphorylase protein expression and blood glucose level, whereas the glycogen content decreased. The enzyme activity of several components of the antioxidant system in the gills, including catalase, glutathione peroxidase, and superoxidase dismutase, increased in enzyme activity. Based on the above data, we concluded that T. microlepis is a hypoxia-tolerant species that does not exhibit ion-regulatory suppression but uses glycogen to maintain energy utilization in the gills under hypoxic stress. Components of the antioxidant system showed increased expression under the applied experimental treatments. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of genotype and dietary fish oil replacement with vegetable oil on the intestinal transcriptome and proteome of Atlantic salmon (Salmo salar)

PubMed Central

2012-01-01

Background Expansion of aquaculture requires alternative feeds and breeding strategies to reduce dependency on fish oil (FO) and better utilization of dietary vegetable oil (VO). Despite the central role of intestine in maintaining body homeostasis and health, its molecular response to replacement of dietary FO by VO has been little investigated. This study employed transcriptomic and proteomic analyses to study effects of dietary VO in two family groups of Atlantic salmon selected for flesh lipid content, 'Lean' or 'Fat'. Results Metabolism, particularly of lipid and energy, was the functional category most affected by diet. Important effects were also measured in ribosomal proteins and signalling. The long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis pathway, assessed by fatty acid composition and gene expression, was influenced by genotype. Intestinal tissue contents of docosahexaenoic acid were equivalent in Lean salmon fed either a FO or VO diet and expression of LC-PUFA biosynthesis genes was up-regulated in VO-fed fish in Fat salmon. Dietary VO increased lipogenesis in Lean fish, assessed by expression of FAS, while no effect was observed on β-oxidation although transcripts of the mitochondrial respiratory chain were down-regulated, suggesting less active energetic metabolism in fish fed VO. In contrast, dietary VO up-regulated genes and proteins involved in detoxification, antioxidant defence and apoptosis, which could be associated with higher levels of polycyclic aromatic hydrocarbons in this diet. Regarding genotype, the following pathways were identified as being differentially affected: proteasomal proteolysis, response to oxidative and cellular stress (xenobiotic and oxidant metabolism and heat shock proteins), apoptosis and structural proteins particularly associated with tissue contractile properties. Genotype effects were accentuated by dietary VO. Conclusions Intestinal metabolism was affected by diet and genotype. Lean fish may have higher responsiveness to low dietary n-3 LC-PUFA, up-regulating the biosynthetic pathway when fed dietary VO. As global aquaculture searches for alternative oils for feeds, this study alerts to the potential of VO introducing contaminants and demonstrates the detoxifying role of intestine. Finally, data indicate genotype-specific responses in the intestinal transcriptome and proteome to dietary VO, including possibly structural properties of the intestinal layer and defence against cellular stress, with Lean fish being more susceptible to diet-induced oxidative stress. PMID:22943471

Coordinated gene expression during gilthead sea bream skeletogenesis and its disruption by nutritional hypervitaminosis A.

PubMed

Fernández, Ignacio; Darias, Maria; Andree, Karl B; Mazurais, David; Zambonino-Infante, Jose Luís; Gisbert, Enric

2011-02-09

Vitamin A (VA) has a key role in vertebrate morphogenesis, determining body patterning and growth through the control of cell proliferation and differentiation processes. VA regulates primary molecular pathways of those processes by the binding of its active metabolite (retinoic acid) to two types of specific nuclear receptors: retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which promote transcription of downstream target genes. This process is well known in most of higher vertebrates; however, scarce information is available regarding fishes. Therefore, in order to gain further knowledge of fish larval development and its disruption by nutritional VA imbalance, the relative expression of some RARs and RXRs, as well as several genes involved in morpho- and skeletogenesis such as peroxisome proliferator-activated receptors (PPARA, PPARB and PPARG); retinol-binding protein (RBP); insulin-like growth factors I and II (IGF1 and IGF2, respectively); bone morphogenetic protein 2 (Bmp2); transforming growth factor β-1 (TGFB1); and genes encoding different extracellular matrix (ECM) proteins such as matrix Gla protein (mgp), osteocalcin (bglap), osteopontin (SPP1), secreted protein acidic and rich in cysteine (SPARC) and type I collagen α1 chain (COL1A1) have been studied in gilthead sea bream. During gilthead sea bream larval development, specific expression profiles for each gene were tightly regulated during fish morphogenesis and correlated with specific morphogenetic events and tissue development. Dietary hypervitaminosis A during early larval development disrupted the normal gene expression profile for genes involved in RA signalling (RARA), VA homeostasis (RBP) and several genes encoding ECM proteins that are linked to skeletogenesis, such as bglap and mgp. Present data reflects the specific gene expression patterns of several genes involved in larval fish RA signalling and skeletogenesis; and how specific gene disruption induced by a nutritional VA imbalance underlie the skeletal deformities. Our results are of basic interest for fish VA signalling and point out some of the potential molecular players involved in fish skeletogenesis. Increased incidences of skeletal deformities in gilthead sea bream fed with hypervitaminosis A were the likely ultimate consequence of specific gene expression disruption at critical development stages.

Coordinated gene expression during gilthead sea bream skeletogenesis and its disruption by nutritional hypervitaminosis A

PubMed Central

2011-01-01

Background Vitamin A (VA) has a key role in vertebrate morphogenesis, determining body patterning and growth through the control of cell proliferation and differentiation processes. VA regulates primary molecular pathways of those processes by the binding of its active metabolite (retinoic acid) to two types of specific nuclear receptors: retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which promote transcription of downstream target genes. This process is well known in most of higher vertebrates; however, scarce information is available regarding fishes. Therefore, in order to gain further knowledge of fish larval development and its disruption by nutritional VA imbalance, the relative expression of some RARs and RXRs, as well as several genes involved in morpho- and skeletogenesis such as peroxisome proliferator-activated receptors (PPARA, PPARB and PPARG); retinol-binding protein (RBP); insulin-like growth factors I and II (IGF1 and IGF2, respectively); bone morphogenetic protein 2 (Bmp2); transforming growth factor β-1 (TGFB1); and genes encoding different extracellular matrix (ECM) proteins such as matrix Gla protein (mgp), osteocalcin (bglap), osteopontin (SPP1), secreted protein acidic and rich in cysteine (SPARC) and type I collagen α1 chain (COL1A1) have been studied in gilthead sea bream. Results During gilthead sea bream larval development, specific expression profiles for each gene were tightly regulated during fish morphogenesis and correlated with specific morphogenetic events and tissue development. Dietary hypervitaminosis A during early larval development disrupted the normal gene expression profile for genes involved in RA signalling (RARA), VA homeostasis (RBP) and several genes encoding ECM proteins that are linked to skeletogenesis, such as bglap and mgp. Conclusions Present data reflects the specific gene expression patterns of several genes involved in larval fish RA signalling and skeletogenesis; and how specific gene disruption induced by a nutritional VA imbalance underlie the skeletal deformities. Our results are of basic interest for fish VA signalling and point out some of the potential molecular players involved in fish skeletogenesis. Increased incidences of skeletal deformities in gilthead sea bream fed with hypervitaminosis A were the likely ultimate consequence of specific gene expression disruption at critical development stages. PMID:21306609

DNA methyltransferase expressions in Japanese rice fish (Oryzias latipes) embryogenesis is developmentally regulated and modulated by ethanol and 5-azacytidine

USDA-ARS?s Scientific Manuscript database

We aimed to investigate the impact of the epigenome in inducting fetal alcohol spectrum disorder (FASD) phenotypes in Japanese rice fish embryogenesis. One of the significant events in epigenome is DNA methylation which is catalyzed by DNA methyl transferase (DNMT) enzymes. We analyzed DNMT enzyme m...

Photoperiodic Modulation of Circadian Clock and Reproductive Axis Gene Expression in the Pre-Pubertal European Sea Bass Brain

PubMed Central

Martins, Rute S. T.; Gomez, Ana; Zanuy, Silvia; Carrillo, Manuel; Canário, Adelino V. M.

2015-01-01

The acquisition of reproductive competence requires the activation of the brain-pituitary-gonad (BPG) axis, which in most vertebrates, including fishes, is initiated by changes in photoperiod. In the European sea bass long-term exposure to continuous light (LL) alters the rhythm of reproductive hormones, delays spermatogenesis and reduces the incidence of precocious males. In contrast, an early shift from long to short photoperiod (AP) accelerates spermatogenesis. However, how photoperiod affects key genes in the brain to trigger the onset of puberty is still largely unknown. Here, we investigated if the integration of the light stimulus by clock proteins is sufficient to activate key genes that trigger the BPG axis in the European sea bass. We found that the clock genes clock, npas2, bmal1 and the BPG genes gnrh, kiss and kissr share conserved transcription factor frameworks in their promoters, suggesting co-regulation. Other gene promoters of the BGP axis were also predicted to be co-regulated by the same frameworks. Co-regulation was confirmed through gene expression analysis of brains from males exposed to LL or AP photoperiod compared to natural conditions: LL fish had suppressed gnrh1, kiss2, galr1b and esr1, while AP fish had stimulated npas2, gnrh1, gnrh2, kiss2, kiss1rb and galr1b compared to NP. It is concluded that fish exposed to different photoperiods present significant expression differences in some clock and reproductive axis related genes well before the first detectable endocrine and morphological responses of the BPG axis. PMID:26641263

Molecular cloning, expression analysis and functional characterization of interleukin-22 in So-iny mullet, Liza haematocheila.

PubMed

Qi, Zhitao; Zhang, Qihuan; Wang, Zisheng; Zhao, Weihong; Chen, Shannan; Gao, Qian

2015-02-01

In the present study, interleukin-22 (IL-22) from So-iny mullet (Liza haematocheila) was identified, and its tissue expression in both healthy and Streptococcus dysgalactiae-infected fish was examined. The full length cDNA sequence of mullet IL-22 was 1070bp, containing an open reading frame of 555bp. The deduced amino acid sequence shared high similarity (45.1-67.9%) with IL-22 from other fish species. Mullet IL-22 also contained an IL-10 family signature and four cysteine residues that were well conserved in other vertebrate IL-22 molecules. Mullet IL-22 mRNA was highly expressed in kidney, moderately expressed in liver and gut, and relatively weakly expressed in spleen, and its expression was significantly up-regulated in all the examined tissues following S. dysgalactiae infection. Furthermore, recombinant mullet IL-22 protein was shown to promote the expression of β-defensin in the four tissues and to increase the survival rate of the fish infected with S. dysgalactiae. Our results suggest mullet IL-22 plays an important role in the immune defense against bacterial infection and has the potential to be used to treat bacterial diseases in fish. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transcriptomic analyses of tributyltin-induced sexual dimorphisms in rare minnow (Gobiocypris rarus) brains.

PubMed

Zhang, Ji-Liang; Liu, Min; Zhang, Chun-Nuan; Li, Er-Chao; Fan, Ming-Zhen; Huang, Mao-Xian

2018-07-30

The brain of fish displays sexual dimorphisms and exhibits remarkable sexual plasticity throughout their life span. Although reproductive toxicity of tributyltin (TBT) in fish is well documented in fish, it remains unknown whether TBT interrupts sexual dimorphisms of fish brains. In this work, brain transcriptomic profiles of rare minnow (Gobiocypris rarus) was characterized and sex-biased genes were identified using RNA sequencing. Functional annotation and enrichment analysis were performed to reveal differences of gene products and pathways between the brains of male and female fish. Furthermore, transcriptomic responses of male and female brains to TBT at 10 ng/L were also investigated to understand effects of TBT on brain sexual dimorphisms. Only 345 male-biased and 273 female-biased genes were found in the brains. However, significant female-biased pathways of circadian rhythm and phototransduction were identified in the brains by enrichment analysis. Interestingly, following TBT exposure in the female fish, the circadian rhythm pathway was significantly disrupted based on enrichment analysis, while in the male fish, the phototransduction pathway was significantly disrupted. In the female fish, expression of genes (Per, Cry, Rev-Erb α, Ror, Dec and CK1δ/ε) in the circadian rhythm pathway was down-regulated after TBT exposure; while in the male fish, expression of genes (Rec, GNAT1_2, GNGT1, Rh/opsin, PDE and Arr) in the phototransduction pathway was up-regulated after TBT exposure. Overall, our results not only provide key data on the molecular basis of brain sexual dimorphisms in fish, but also offer valuable resources for investigating molecular mechanisms by which environmental chemicals might influence brain sexual plasticity. Copyright © 2018 Elsevier Inc. All rights reserved.

Cart Regulates Food Intake in Channel Catfish

USDA-ARS?s Scientific Manuscript database

Cocaine-and Amphetamine-Regulated Transcript (CART) is a potent hypothalamic anorectic peptide in mammals and fish. We hypothesized that increased food intake is associated with changes in expression of CART mRNA within the brain of channel catfish. Objectives were to clone the CART gene, examine ...

RNA-Seq analysis of salinity stress-responsive transcriptome in the liver of spotted sea bass (Lateolabrax maculatus).

PubMed

Zhang, Xiaoyan; Wen, Haishen; Wang, Hailiang; Ren, Yuanyuan; Zhao, Ji; Li, Yun

2017-01-01

Salinity is one of the most prominent abiotic factors, which greatly influence reproduction, development, growth, physiological and metabolic activities of fishes. Spotted sea bass (Lateolabrax maculatus), as a euryhaline marine teleost, has extraordinary ability to deal with a wide range of salinity changes. However, this species is devoid of genomic resources, and no study has been conducted at the transcriptomic level to determine genes responsible for salinity regulation, which impedes the understanding of the fundamental mechanism conferring tolerance to salinity fluctuations. Liver, as the major metabolic organ, is the key source supplying energy for iono- and osmoregulation in fish, however, little attention has been paid to its salinity-related functions but which should not be ignored. In this study, we perform RNA-Seq analysis to identify genes involved in salinity adaptation and osmoregulation in liver of spotted sea bass, generating from the fishes exposed to low and high salinity water (5 vs 30ppt). After de novo assembly, annotation and differential gene expression analysis, a total of 455 genes were differentially expressed, including 184 up-regulated and 271 down-regulated transcripts in low salinity-acclimated fish group compared with that in high salinity-acclimated group. A number of genes with a potential role in salinity adaptation for spotted sea bass were classified into five functional categories based on the gene ontology (GO) and enrichment analysis, which include genes involved in metabolites and ion transporters, energy metabolism, signal transduction, immune response and structure reorganization. The candidate genes identified in L. maculates liver provide valuable information to explore new pathways related to fish salinity and osmotic regulation. Besides, the transcriptomic sequencing data supplies significant resources for identification of novel genes and further studying biological questions in spotted sea bass.

RNA-Seq analysis of salinity stress–responsive transcriptome in the liver of spotted sea bass (Lateolabrax maculatus)

PubMed Central

Zhang, Xiaoyan; Wen, Haishen; Wang, Hailiang; Ren, Yuanyuan; Zhao, Ji; Li, Yun

2017-01-01

Salinity is one of the most prominent abiotic factors, which greatly influence reproduction, development, growth, physiological and metabolic activities of fishes. Spotted sea bass (Lateolabrax maculatus), as a euryhaline marine teleost, has extraordinary ability to deal with a wide range of salinity changes. However, this species is devoid of genomic resources, and no study has been conducted at the transcriptomic level to determine genes responsible for salinity regulation, which impedes the understanding of the fundamental mechanism conferring tolerance to salinity fluctuations. Liver, as the major metabolic organ, is the key source supplying energy for iono- and osmoregulation in fish, however, little attention has been paid to its salinity-related functions but which should not be ignored. In this study, we perform RNA-Seq analysis to identify genes involved in salinity adaptation and osmoregulation in liver of spotted sea bass, generating from the fishes exposed to low and high salinity water (5 vs 30ppt). After de novo assembly, annotation and differential gene expression analysis, a total of 455 genes were differentially expressed, including 184 up-regulated and 271 down-regulated transcripts in low salinity-acclimated fish group compared with that in high salinity-acclimated group. A number of genes with a potential role in salinity adaptation for spotted sea bass were classified into five functional categories based on the gene ontology (GO) and enrichment analysis, which include genes involved in metabolites and ion transporters, energy metabolism, signal transduction, immune response and structure reorganization. The candidate genes identified in L. maculates liver provide valuable information to explore new pathways related to fish salinity and osmotic regulation. Besides, the transcriptomic sequencing data supplies significant resources for identification of novel genes and further studying biological questions in spotted sea bass. PMID:28253338

Nutrient Sensing Systems in Fish: Impact on Food Intake Regulation and Energy Homeostasis

PubMed Central

Conde-Sieira, Marta; Soengas, José L.

2017-01-01

Evidence obtained in recent years in a few species, especially rainbow trout, supports the presence in fish of nutrient sensing mechanisms. Glucosensing capacity is present in central (hypothalamus and hindbrain) and peripheral [liver, Brockmann bodies (BB, main accumulation of pancreatic endocrine cells in several fish species), and intestine] locations whereas fatty acid sensors seem to be present in hypothalamus, liver and BB. Glucose and fatty acid sensing capacities relate to food intake regulation and metabolism in fish. Hypothalamus is as a signaling integratory center in a way that detection of increased levels of nutrients result in food intake inhibition through changes in the expression of anorexigenic and orexigenic neuropeptides. Moreover, central nutrient sensing modulates functions in the periphery since they elicit changes in hepatic metabolism as well as in hormone secretion to counter-regulate changes in nutrient levels detected in the CNS. At peripheral level, the direct nutrient detection in liver has a crucial role in homeostatic control of glucose and fatty acid whereas in BB and intestine nutrient sensing is probably involved in regulation of hormone secretion from endocrine cells. PMID:28111540

The Regulation of Non-Coding RNA Expression in the Liver of Mice Fed DDC

PubMed Central

Oliva, Joan; Bardag-Gorce, Fawzia; French, Barbara A; Li, Jun; French, Samuel W

2010-01-01

Mallory-Denk bodies (MDBs) are found in the liver of patients with alcoholic and chronic nonalcoholic liver disease, and hepatocellular carcinoma (HCC). Diethyl 1,4-dihydro-2,4,6,-trimethyl-3,5-pyridinedicarboxylate (DDC) is used as a model to induce the formation of MDBs in mouse liver. Previous studies in this laboratory showed that DDC induced epigenetic modifications in DNA and histones. The combination of these modifications changes the phenotype of the MDB forming hepatocytes, as indicated by the marker FAT10. These epigenetic modifications are partially prevented by adding to the diet S-adenosylmethionine (SAMe) or betaine, both methyl donors. The expression of three imprinted ncRNA genes was found to change in MDB forming hepatocytes, which is the subject of this report. NcRNA expression was quantitated by Real-Time PCR and RNA FISH in liver sections. Microarray analysis showed that the expression of three ncRNAs was regulated by DDC: up regulation of H19, antisense Igf2r (AIR), and down regulation of GTL2 (also called MEG3). S-adenosylmethionine (SAMe) feeding prevented these changes. Betaine, another methyl group donor, prevented only H19 and AIR up regulation induced by DDC, on microarrays. The results of the SAMe and betaine groups were confirmed by Real-Time PCR, except for AIR expression. After 1 month of drug withdrawal, the expression of the three ncRNAs tended toward control levels of expression. Liver tumors that developed also showed up regulation of H19 and AIR. The RNA FISH approach showed that the MDB forming cells’ phenotype changed the level of expression of AIR, H19 and GTL2, compared to the surrounding cells. Furthermore, over expression of H19 and AIR was demonstrated in tumors formed in mice withdrawn for 9 months. The disregulation of ncRNA in MDB forming liver cells has been observed for the first time in drug primed mice associated with liver preneoplastic foci and tumors. PMID:19362547

The regulation of non-coding RNA expression in the liver of mice fed DDC.

PubMed

Oliva, Joan; Bardag-Gorce, Fawzia; French, Barbara A; Li, Jun; French, Samuel W

2009-08-01

Mallory-Denk bodies (MDBs) are found in the liver of patients with alcoholic and chronic nonalcoholic liver disease, and hepatocellular carcinoma (HCC). Diethyl 1,4-dihydro-2,4,6,-trimethyl-3,5-pyridinedicarboxylate (DDC) is used as a model to induce the formation of MDBs in mouse liver. Previous studies in this laboratory showed that DDC induced epigenetic modifications in DNA and histones. The combination of these modifications changes the phenotype of the MDB forming hepatocytes, as indicated by the marker FAT10. These epigenetic modifications are partially prevented by adding to the diet S-adenosylmethionine (SAMe) or betaine, both methyl donors. The expression of three imprinted ncRNA genes was found to change in MDB forming hepatocytes, which is the subject of this report. NcRNA expression was quantitated by real-time PCR and RNA FISH in liver sections. Microarray analysis showed that the expression of three ncRNAs was regulated by DDC: up regulation of H19, antisense Igf2r (AIR), and down regulation of GTL2 (also called MEG3). S-adenosylmethionine (SAMe) feeding prevented these changes. Betaine, another methyl group donor, prevented only H19 and AIR up regulation induced by DDC, on microarrays. The results of the SAMe and betaine groups were confirmed by real-time PCR, except for AIR expression. After 1 month of drug withdrawal, the expression of the three ncRNAs tended toward control levels of expression. Liver tumors that developed also showed up regulation of H19 and AIR. The RNA FISH approach showed that the MDB forming cells' phenotype changed the level of expression of AIR, H19 and GTL2, compared to the surrounding cells. Furthermore, over expression of H19 and AIR was demonstrated in tumors formed in mice withdrawn for 9 months. The dysregulation of ncRNA in MDB forming liver cells has been observed for the first time in drug-primed mice associated with liver preneoplastic foci and tumors.

Indoleamine 2,3-dioxygenase: First evidence of expression in rainbow trout (Oncorhynchus mykiss).

PubMed

Cortés, Jimena; Alvarez, Claudio; Santana, Paula; Torres, Elisa; Mercado, Luis

2016-12-01

The role of enzymes as active antimicrobial agents of the innate immunity in teleost fish is proposed in diverse works. Secretion of Indoleamine 2,3-dioxygenase (IDO) has been described in higher vertebrates; it degrades l-tryptophan in extracellular environments associated mainly with mucosal organs. The effect of IDO on decreasing amino acid concentration may inhibit the growth of potential pathogens. In fish the study of this molecule is still. Here we report the identification of an Onchorhyncus mykiss IDO homologue (OmIDO). IDO was cloned, sequenced, and the primary structure shows conservation of key functional sites. The constitutive expression is altered when the fish is challenged with LPS as a pathogen-associated molecular pattern (PAMPs). Up-regulation of IDO was shown preferentially in the fish's mucosal cells. In order to obtain evidence of a possible regulation mechanism, an in vitro cell model was used for to show that OmIDO is induced by rIFN. These study has identified a Indoleamine 2,3-dyoxigenase in O. mykiss will contribute to expands our knowledge of the function this protein in fish immune response. These findings allow to propose the use of OmIDO as a molecular indicator of strength of the animal's immune response and wellbeing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physiological Responses in Chinese Rare Minnow Larvae Following Exposure to Low-Dose Tributyltin.

PubMed

Li, Ping; Li, Zhi-Hua

2015-11-01

In the present study, the antioxidant response and acetylcholinesterase (AChE) activity were measured in Chinese rare minnow larvae (Gobiocypris rarus) after exposure to tributyltin (TBT) (0, 100, 400 and 800 ngL(-1)) for 7 days, as well as the expression of a series of genes, including cr, aptase and prl genes involved in the ion-regulatory process and igfbp3 and gh related to growth rate. Results shows that oxidative stress was generated in fish exposed to TBT, as evidenced by elevated malondialdehyde levels and the inhibition of antioxidant parameters. The activity of acetylcholinesterase (AChE) was also inhibited in fish under higher TBT stress. Moreover, genes involved in ion regulation and growth were affected, based on the regulated transcription of the cr, atpase, gh, prl and igfbp3 genes in the treated groups. The observed effects of TBT upon antioxidant responses and altered expression of genes provides insight into the use of these molecular biomarkers in evaluating mechanisms of TBT toxicity in fish.

Thyroid hormone regulates muscle function during cold acclimation in zebrafish (Danio rerio).

PubMed

Little, Alexander G; Seebacher, Frank

2013-09-15

Thyroid hormone (TH) is a universal regulator of growth, development and metabolism during cold exposure in mammals. In zebrafish (Danio rerio), TH regulates locomotor performance and metabolism during cold acclimation. The influence of TH on locomotor performance may be via its effect on metabolism or, as has been shown in mammals, by modulating muscle phenotypes. Our aim was to determine whether TH influences muscle phenotypes in zebrafish, and whether this could explain changes in swimming capacity in response to thermal acclimation. We used propylthiouracil and iopanoic acid to induce hypothyroidism in zebrafish over a 3-week acclimation period to either 18 or 28°C. To verify that physiological changes following hypothyroid treatment were in fact due to the action of TH, we supplemented hypothyroid fish with 3,5-diiodothryronine (T2) or 3,5,3'-triiodothyronine (T3). Cold-acclimated fish had significantly greater sustained swimming performance (Ucrit) but not burst speed. Greater Ucrit was accompanied by increased tail beat frequency, but there was no change in tail beat amplitude. Hypothyroidism significantly decreased Ucrit and burst performance, as well as tail beat frequency and SERCA activity in cold-acclimated fish. However, myofibrillar ATPase activity increased in cold-acclimated hypothyroid fish. Hypothyroid treatment also decreased mRNA concentrations of myosin heavy chain fast isoforms and SERCA 1 isoform in cold-acclimated fish. SERCA 1 mRNA increased in warm-acclimated hypothyroid fish, and SERCA 3 mRNA decreased in both cold- and warm-acclimated hypothyroid fish. Supplementation with either T2 or T3 restored Ucrit, burst speed, tail beat frequency, SERCA activity and myosin heavy chain and SERCA 1 and 3 mRNA levels of hypothyroid fish back to control levels. We show that in addition to regulating development and metabolism in vertebrates, TH also regulates muscle physiology in ways that affect locomotor performance in fish. We suggest that the role of TH in modulating SERCA1 expression during cold exposure may have predisposed it to regulate endothermic thermogenesis.

Rapid Steroid Hormone Actions Initiated at the Cell Surface and the Receptors that Mediate Them with an Emphasis on Recent Progress in Fish Models

PubMed Central

Thomas, Peter

2011-01-01

In addition to the classic genomic mechanism of steroid action mediated by activation of intracellular nuclear receptors, there is now extensive evidence that steroids also activate receptors on the cell surface to initiate rapid intracellular signaling and biological responses that are often nongenomic. Recent progress in our understanding of rapid, cell surface-initiated actions of estrogens, progestins, androgens and corticosteroids and the identities of the membrane receptors that act as their intermediaries is briefly reviewed with a special emphasis on studies in teleost fish. Two recently discovered novel proteins with seven-transmembrane domains, G protein-coupled receptor 30 (GPR30), and membrane progestin receptors (mPRs) have the ligand binding and signaling characteristics of estrogen and progestin membrane receptors, respectively, but their functional significance is disputed by some researchers. GPR30 is expressed on the cell surface of fish oocytes and mediates estrogen inhibition of oocyte maturation. mPRα is also expressed on the oocyte cell surface and is the intermediary in progestin induction of oocyte maturation in fish. Recent results suggest there is cross-talk between these two hormonal pathways and that there is reciprocal down-regulation of GPR30 and mPRα expression by estrogens and progestins at different phases of oocyte development to regulate the onset of oocyte maturation. There is also evidence in fish that mPRs are involved in progestin induction of sperm hypermotility and anti-apoptotic actions in ovarian follicle cells. Nonclassical androgen and corticosteroid actions have also been described in fish models but the membrane receptors mediating these actions have not been identified. PMID:22154643

In vitro effects of metals on isolated head-kidney and blood leucocytes of the teleost fish Sparus aurata L. and Dicentrarchus labrax L.

PubMed

Morcillo, Patricia; Meseguer, José; Esteban, M Ángeles; Cuesta, Alberto

2016-07-01

The in vitro use of fish leucocytes to test the toxicity of aquatic pollutants, and particularly the immutoxicological effects, could be a valuable alternative to fish bioassays but has received little attention. In this study, head-kidney and peripheral blood leucocytes (HKLs and PBLs, respectively) from gilthead seabream (Sparus aurata L.) and European sea bass (Dicentrarchus labrax L.) specimens were exposed to Cd, MeHg (methylmercury), Pb or As for 24 h being evaluated the resulting cytotoxicity. Exposure to metals produced a dose-dependent reduction in the viability, and MeHg showed the highest toxicity followed by Cd, As and Pb. Interestingly, leucocytes from European sea bass are more resistant to metal exposure than those from gilthead seabream. Similarly, HKLs are always more sensitive than those isolated from blood from the same fish species. Moreover, fish leucocytes incubated with metals exhibited alterations in gene expression profiles that were more pronounced in the HKLs in general, being Pb the metal provoking less effects. Concretely, genes related to cellular protection (metallothionein), stress (heat shock protein 70) and oxidative stress (superoxide dismutase, catalase and glutathione reductase) were, in general, down-regulated in seabream HKLs but up-regulated in seabream PBLs and sea bass HKLs and PBLs. In addition, this profile leads to the increase of expression in genes related to apoptosis (Bcl2 associated X protein and caspase 3). Finally, transcription of genes involved in immunity (interleukin-1β and immunoglobulin M) was down-regulated, mainly in seabream leucocytes. This study points to the benefits for evaluating the toxicological mechanisms of marine pollution using fish leucocytes in vitro and insight into the mechanisms at gene level. Copyright © 2016 Elsevier Ltd. All rights reserved.

Proglucagons in vertebrates: Expression and processing of multiple genes in a bony fish.

PubMed

Busby, Ellen R; Mommsen, Thomas P

2016-09-01

In contrast to mammals, where a single proglucagon (PG) gene encodes three peptides: glucagon, glucagon-like peptide 1 and glucagon-like peptide 2 (GLP-1; GLP-2), many non-mammalian vertebrates carry multiple PG genes. Here, we investigate proglucagon mRNA sequences, their tissue expression and processing in a diploid bony fish. Copper rockfish (Sebastes caurinus) express two independent genes coding for distinct proglucagon sequences (PG I, PG II), with PG II lacking the GLP-2 sequence. These genes are differentially transcribed in the endocrine pancreas, the brain, and the gastrointestinal tract. Alternative splicing identified in rockfish is only one part of this complex regulation of the PG transcripts: the system has the potential to produce two glucagons, four GLP-1s and a single GLP-2, or any combination of these peptides. Mass spectrometric analysis of partially purified PG-derived peptides in endocrine pancreas confirms translation of both PG transcripts and differential processing of the resulting peptides. The complex differential regulation of the two PG genes and their continued presence in this extant teleostean fish strongly suggests unique and, as yet largely unidentified, roles for the peptide products encoded in each gene. Copyright © 2016 Elsevier Inc. All rights reserved.

Inhibition of myostatin gene expression in skeletal muscle of fish by in vivo electrically mediated dsRNA and shRNAi delivery.

PubMed

Terova, Genciana; Rimoldi, Simona; Bernardini, Giovanni; Saroglia, Marco

2013-06-01

Myostatin (MSTN), previously referred to as growth differentiation factor 8 (GDF8), is a negative regulator of skeletal muscle growth. In accordance with this role, natural mutations that inactivate the gene disrupting the function of the protein are associated with excessive muscle growth and double-muscling phenotype in several mammalian species. Recent studies using transgenic MSTN deficient zebrafish and medaka support the idea that this gene inhibits skeletal muscle growth even in fish. If the atrophic actions of mammalian MSTN are indeed conserved in fish, strategies capable of inhibiting the expression of this gene could be applied to enhance growth performance in livestock production. Gene silencing by RNA interference has emerged as a promising new method of inhibiting the expression of targeted genes and inducing knockdown of associated proteins both in vitro and in vivo. Accordingly, we investigated here whether double-stranded RNA (dsRNA) or different plasmids expressing short-hairpin interfering RNAs (shRNAs) against myostatin and transduced by in vivo electroporation would increase skeletal muscle mass in reared European sea bass. After 7 weeks of intramuscular injections on a weekly basis followed by in vivo electrically mediated dsRNA delivery, no increase in the condition factor (K) of fish was observed as compared to the controls. Analogously, mean body weight and K of sea bass injected with three shRNAs were not higher than those of the control fish. On the other hand, MSTN transcript quantification via real-time RT-PCR revealed a significant inhibition of gene expression in the muscle of the dsRNA-injected fish and in the muscle of fish injected with one of the three tested shRNA-expressing vector constructs. In conclusion, in vivo electric-mediated delivery of dsRNA- or shRNA-expressing vectors against MSTN inhibits MSTN gene expression in adult sea bass muscle, but this is associated with an inconsistent double-muscle phenotype.

Antimicrobial Peptides as Mediators of Innate Immunity in Teleosts

PubMed Central

Katzenback, Barbara A.

2015-01-01

Antimicrobial peptides (AMPs) have been identified throughout the metazoa suggesting their evolutionarily conserved nature and their presence in teleosts is no exception. AMPs are short (18–46 amino acids), usually cationic, amphipathic peptides. While AMPs are diverse in amino acid sequence, with no two AMPs being identical, they collectively appear to have conserved functions in the innate immunity of animals towards the pathogens they encounter in their environment. Fish AMPs are upregulated in response to pathogens and appear to have direct broad-spectrum antimicrobial activity towards both human and fish pathogens. However, an emerging role for AMPs as immunomodulatory molecules has become apparent—the ability of AMPs to activate the innate immune system sheds light onto the multifaceted capacity of these small peptides to combat pathogens through direct and indirect means. Herein, this review focuses on the role of teleost AMPs as modulators of the innate immune system and their regulation in response to pathogens or other exogenous molecules. The capacity to regulate AMP expression by exogenous factors may prove useful in modulating AMP expression in fish to prevent disease, particularly in aquaculture settings where crowded conditions and environmental stress pre-dispose these fish to infection. PMID:26426065

Effect of dietary glutamine on growth performance, non-specific immunity, expression of cytokine genes, phosphorylation of target of rapamycin (TOR), and anti-oxidative system in spleen and head kidney of Jian carp (Cyprinus carpio var. Jian).

PubMed

Hu, Kai; Zhang, Jing-Xiu; Feng, Lin; Jiang, Wei-Dan; Wu, Pei; Liu, Yang; Jiang, Jun; Zhou, Xiao-Qiu

2015-06-01

This study was designed to investigate the effects of dietary glutamine on the growth performance, cytokines, target of rapamycin (TOR), and antioxidant-related parameters in the spleen and head kidney of juvenile Jian carp (Cyprinus carpio var. Jian). Fish were fed the basal (control) and glutamine-supplemented (12.0 g glutamine kg(-1) diet) diets for 6 weeks. Results indicated that the dietary glutamine supplementation improved the growth performance, spleen protein content, serum complement 3 content, and lysozyme activity in fish. In the spleen, glutamine down-regulated the expression of the interleukin 1 and interleukin 10 genes, and increased the level of phosphorylation of TOR protein. In the head kidney, glutamine down-regulated the tumor necrosis factor α and interleukin 10 gene expressions, phosphorylated and total TOR protein levels, while up-regulated the transforming growth factor β2 gene expression. Furthermore, the protein carbonyl content was decreased in the spleen of fish fed glutamine-supplemented diet; conversely, the anti-hydroxyl radical capacity and glutathione content in the spleen were increased by glutamine. However, diet supplemented with glutamine did not affect the lipid peroxidation, anti-superoxide anion capacity, and antioxidant enzyme activities in the spleen. Moreover, all of these antioxidant parameters in the head kidney were not affected by glutamine. Results from the present experiment showed the importance of dietary supplementation of glutamine in benefaction of the growth performance and several components of the innate immune system, and the deferential role in cytokine gene expression, TOR kinase activity, and antioxidant status between the spleen and head kidney of juvenile Jian carp.

Characterization of common carp (Cyprinus carpio L.) interferon regulatory factor 5 (IRF5) and its expression in response to viral and bacterial challenges.

PubMed

Zhu, Yaoyao; Qi, Chenchen; Shan, Shijuan; Zhang, Fumiao; Li, Hua; An, Liguo; Yang, Guiwen

2016-06-27

Common carp (Cyprinus carpio L.), one of the most economically valuable commercial farming fish species in China, is often infected by a variety of viruses. As the first line of defence against microbial pathogens, the innate immune system plays a crucial role in teleost fish, which are lower vertebrates. Interferon (IFN) regulatory factor 5 (IRF5) is a key molecule in antiviral immunity that regulating the expression of IFN and other pro-inflammatory cytokines. It is necessary to gain more insight into the common carp IFN system and the function of fish IRF5 in the antiviral and antibacterial response. In the present study, we characterized the cDNA and genomic sequence of the IRF5 gene in common carp, and analysed tissue distribution and expression profile of this gene in response to polyinosinic:polycytidylic acid (poly I:C) and lipopolysaccharides (LPS) treatment. The common carp IRF5 (ccIRF5) gene is 5790 bp in length and is composed of 9 exons and 8 introns. The open reading frame (ORF) of ccIRF5 is 1554 bp, and encodes 517 amino acid protein. The putative ccIRF5 protein shares identity (65.4-90.0 %) with other fish IRF5s and contains a DNA binding domain (DBD), a middle region (MR), an IRF-associated domain (IAD), a virus activated domain (VAD) and two nuclear localization signals (NLSs) similar to those found in vertebrate IRF5. Phylogenetic analysis clustered ccIRF5 into the IRF5 subfamily with other vertebrate IRF5 and IRF6 genes. Real-time PCR analysis revealed that ccIRF5 mRNA was expressed in all examined tissues of healthy carps, with high levels observed in the gills and the brain. After poly I:C challenge, expression levels of ccIRF5, tumour-necrosis factor α (ccTNFα) and two IFN stimulated genes [ISGs (ccISG5 and ccPKR)] were up-regulated in seven immune-related tissues (liver, spleen, head kidney, foregut, hindgut, skin and gills). Furthermore, all four genes were up-regulated in vitro upon poly I:C and LPS challenges. Our findings suggest that IRF5 might play an important role in regulating the antiviral and antibacterial response in fish. These results could provide a clue for preventing common carp infection by pathogenic microorganisms present in the aquatic environment.

Genome-wide transcription analysis of histidine-related cataract in Atlantic salmon (Salmo salar L)

PubMed Central

Waagbø, Rune; Breck, Olav; Stavrum, Anne-Kristin; Petersen, Kjell; Olsvik, Pål A.

2009-01-01

Purpose Elevated levels of dietary histidine have previously been shown to prevent or mitigate cataract formation in farmed Atlantic salmon (Salmo salar L). The aim of this study was to shed light on the mechanisms by which histidine acts. Applying microarray analysis to the lens transcriptome, we screened for differentially expressed genes in search for a model explaining cataract development in Atlantic salmon and possible markers for early cataract diagnosis. Methods Adult Atlantic salmon (1.7 kg) were fed three standard commercial salmon diets only differing in the histidine content (9, 13, and 17 g histidine/kg diet) for four months. Individual cataract scores for both eyes were assessed by slit-lamp biomicroscopy. Lens N-acetyl histidine contents were measured by high performance liquid chromatography (HPLC). Total RNA extracted from whole lenses was analyzed using the GRASP 16K salmonid microarray. The microarray data were analyzed using J-Express Pro 2.7 and validated by quantitative real-time polymerase chain reaction (qRT–PCR). Results Fish developed cataracts with different severity in response to dietary histidine levels. Lens N-acetyl histidine contents reflected the dietary histidine levels and were negatively correlated to cataract scores. Significance analysis of microarrays (SAM) revealed 248 significantly up-regulated transcripts and 266 significantly down-regulated transcripts in fish that were fed a low level of histidine compared to fish fed a higher histidine level. Among the differentially expressed transcripts were metallothionein A and B as well as transcripts involved in lipid metabolism, carbohydrate metabolism, regulation of ion homeostasis, and protein degradation. Hierarchical clustering and correspondence analysis plot confirmed differences in gene expression between the feeding groups. The differentially expressed genes could be categorized as “early” and “late” responsive according to their expression pattern relative to progression in cataract formation. Conclusions Dietary histidine regimes affected cataract formation and lens gene expression in adult Atlantic salmon. Regulated transcripts selected from the results of this genome-wide transcription analysis might be used as possible biological markers for cataract development in Atlantic salmon. PMID:19597568

Conservation of lipid metabolic gene transcriptional regulatory networks in fish and mammals.

PubMed

Carmona-Antoñanzas, Greta; Tocher, Douglas R; Martinez-Rubio, Laura; Leaver, Michael J

2014-01-15

Lipid content and composition in aquafeeds have changed rapidly as a result of the recent drive to replace ecologically limited marine ingredients, fishmeal and fish oil (FO). Terrestrial plant products are the most economic and sustainable alternative; however, plant meals and oils are devoid of physiologically important cholesterol and long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic (EPA), docosahexaenoic (DHA) and arachidonic (ARA) acids. Although replacement of dietary FO with vegetable oil (VO) has little effect on growth in Atlantic salmon (Salmo salar), several studies have shown major effects on the activity and expression of genes involved in lipid homeostasis. In vertebrates, sterols and LC-PUFA play crucial roles in lipid metabolism by direct interaction with lipid-sensing transcription factors (TFs) and consequent regulation of target genes. The primary aim of the present study was to elucidate the role of key TFs in the transcriptional regulation of lipid metabolism in fish by transfection and overexpression of TFs. The results show that the expression of genes of LC-PUFA biosynthesis (elovl and fads2) and cholesterol metabolism (abca1) are regulated by Lxr and Srebp TFs in salmon, indicating highly conserved regulatory mechanism across vertebrates. In addition, srebp1 and srebp2 mRNA respond to replacement of dietary FO with VO. Thus, Atlantic salmon adjust lipid metabolism in response to dietary lipid composition through the transcriptional regulation of gene expression. It may be possible to further increase efficient and effective use of sustainable alternatives to marine products in aquaculture by considering these important molecular interactions when formulating diets. © 2013.

A novel galanin receptor 1a gene in zebrafish: tissue distribution, developmental expression roles in nutrition regulation.

PubMed

Li, Linfang; Wei, Shulei; Huang, Qiaoyan; Feng, Dong; Zhang, Shicui; Liu, Zhenhui

2013-03-01

Galanin (Gal), a 29 (30 in human) amino acid neuropeptide, exerts its biological activities through three different G protein-coupled receptors, namely GalR1, GalR2 and GalR3. However, we previously found that only GalR1 and GalR2 exist in fish, and fish GalR1 has two genes (GalR1a and GalR1b), with GalR1a possibly representing the primitive gene form during fish evolution. To uncover the functions of GalR1a in fish, here the tissue distribution, developmental expression and the role in nutrition regulation of GalR1a were investigated in zebrafish (Danio rerio). Interestingly, the expression of GalR1a mRNA was restricted to the intestine and brain in adult zebrafish, while GalR1b mRNA was present in all tissues tested. During embryogenesis, GalR1a mRNA was abundant at 1hpf (hour past fertilization) and decreased gradually in abundance from 3 hpf to 10 hpf; then a significant increase in the amount of GalR1a transcripts was observed at 35 hpf, and this high level was maintained until 5 dpf (day past fertilization). In situ hybridization of embryos and larvae, expression pattern of GalR1a was mainly restricted to the intestine, pectoral fin, branchial arches and head, indicating a role of GalR1a during zebrafish embryogenesis. Quantitative real-time PCR assay suggested that fasting, high fat feeding or linoleic acid (LA) all could significantly induce up-regulation of GalR1a both in vitro and in vivo, suggesting roles of GalR1a in control of nutrition intake, especially to fat. In addition, a potential role of zebrafish GalR1a in accumulation of lipid droplets in cells was also demonstrated. Our study lays a foundation for further investigation of GalR1a function and evolution in fish. Copyright © 2012 Elsevier Inc. All rights reserved.

Estrogen regulation of gene expression in the teleost fish immune system.

PubMed

Burgos-Aceves, Mario Alberto; Cohen, Amit; Smith, Yoav; Faggio, Caterina

2016-11-01

Elucidating the mechanisms of estrogens-induced immunomodulation in teleost fish is of great importance due to the observed worldwide continuing decrease in pristine environments. However, little is know about the immunotoxicological consequences of exposure to these chemicals in fish, or of the mechanisms through which these effects are mediated. In this review, we summarize the results showing estrogens (natural or synthetic) acting through estrogen receptors and regulating specific target genes, also through microRNAs (miRNAs), leading to modulation of the immune functioning. The identification and characterization of miRNAs will provide new opportunities for functional genome research on teleost immune system and can also be useful when screening for novel molecule biomarkers for environmental pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of TLR agonists and viral infection on cytokine and TLR expression in Atlantic salmon (Salmo salar).

PubMed

Arnemo, Marianne; Kavaliauskis, Arturas; Gjøen, Tor

2014-10-01

The development of efficient and cheap vaccines against several aquatic viruses is necessary for a sustainable fish farming industry. Toll-like receptor (TLR) ligands have already been used as good adjuvants in human vaccines. With more understanding of TLR expression, function, and ligand specificity in fish, more efficient adjuvants for fish viral vaccines can be developed. In this paper, we examine all known TLRs in Atlantic salmon (Salmo salar) and demonstrate that head kidney and spleen are the main organs expressing TLRs in salmon. We also show that adherent head kidney leucocytes from salmon are able to respond to many of the known agonists for human TLRs, and that viral infection can induce up-regulation of several TLRs. These findings substantiate these receptors' role in immune responses to pathogens in salmonids making their ligands attractive as vaccine adjuvant candidates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular Plasticity under Ocean Warming: Proteomics and Fitness Data Provides Clues for a Better Understanding of the Thermal Tolerance in Fish

PubMed Central

Madeira, Diana; Araújo, José E.; Vitorino, Rui; Costa, Pedro M.; Capelo, José L.; Vinagre, Catarina; Diniz, Mário S.

2017-01-01

Ocean warming is known to alter the performance and fitness of marine organisms albeit the proteome underpinnings of species thermal tolerance are still largely unknown. In this 1-month experiment we assessed the vulnerability of the gilt-head sea bream Sparus aurata, taken here as a biological model for some key fisheries species, to ocean warming (control 18°C, nursery ground temperature 24°C and heat wave 30°C). Survival was impaired after 28 days, mainly at 30°C although fishes' condition was unaltered. Muscle proteome modulation was assessed at 14 and 21 days, showing that protein expression profiles were similar between fish exposed to 18 and 24°C, differing from fish exposed to 30°C. Fish subjected to 24°C showed an enhanced glycolytic potential and decreased glycogenolysis mainly at 14 days of exposure. Fish subjected to 30°C also showed enhanced glycolytic potential and up-regulated proteins related to gene expression, cellular stress response (CSR), and homeostasis (mostly cytoskeletal dynamics, acid-base balance, chaperoning). However, inflammatory processes were elicited at 21 days along with a down-regulation of the tricarboxylic acid cycle. Thus, juvenile fish seem able to acclimate to 24°C but possibly not to 30°C, which is the predicted temperature for estuaries during heat waves by the year 2100. This may be related with increasing constraints on organism physiology associated with metabolic scope available for performance and fitness at higher temperatures. Consequently, recruitment of commercial sea breams may be in jeopardy, highlighting the need for improved management plans for fish stocks. PMID:29109689

Molecular Plasticity under Ocean Warming: Proteomics and Fitness Data Provides Clues for a Better Understanding of the Thermal Tolerance in Fish.

PubMed

Madeira, Diana; Araújo, José E; Vitorino, Rui; Costa, Pedro M; Capelo, José L; Vinagre, Catarina; Diniz, Mário S

2017-01-01

Ocean warming is known to alter the performance and fitness of marine organisms albeit the proteome underpinnings of species thermal tolerance are still largely unknown. In this 1-month experiment we assessed the vulnerability of the gilt-head sea bream Sparus aurata , taken here as a biological model for some key fisheries species, to ocean warming (control 18°C, nursery ground temperature 24°C and heat wave 30°C). Survival was impaired after 28 days, mainly at 30°C although fishes' condition was unaltered. Muscle proteome modulation was assessed at 14 and 21 days, showing that protein expression profiles were similar between fish exposed to 18 and 24°C, differing from fish exposed to 30°C. Fish subjected to 24°C showed an enhanced glycolytic potential and decreased glycogenolysis mainly at 14 days of exposure. Fish subjected to 30°C also showed enhanced glycolytic potential and up-regulated proteins related to gene expression, cellular stress response (CSR), and homeostasis (mostly cytoskeletal dynamics, acid-base balance, chaperoning). However, inflammatory processes were elicited at 21 days along with a down-regulation of the tricarboxylic acid cycle. Thus, juvenile fish seem able to acclimate to 24°C but possibly not to 30°C, which is the predicted temperature for estuaries during heat waves by the year 2100. This may be related with increasing constraints on organism physiology associated with metabolic scope available for performance and fitness at higher temperatures. Consequently, recruitment of commercial sea breams may be in jeopardy, highlighting the need for improved management plans for fish stocks.

Transcriptional Repressor foxl1 Regulates Central Nervous System Development by Suppressing shh Expression in Zebra Fish†

PubMed Central

Nakada, Chisako; Satoh, Shinya; Tabata, Yoko; Arai, Ken-ichi; Watanabe, Sumiko

2006-01-01

We identified zebra fish forkhead transcription factor l1 (zfoxl1) as a gene strongly expressed in neural tissues such as midbrain, hindbrain, and the otic vesicle at the early embryonic stage. Loss of the function of zfoxl1 effected by morpholino antisense oligonucleotide resulted in defects in midbrain and eye development, and in that of formation of the pectoral fins. Interestingly, ectopic expression of shh in the midbrain and elevated pax2a expression in the optic stalk were observed in foxl1 MO-injected embryos. In contrast, expression of pax6a, which is negatively regulated by shh, was suppressed in the thalamus and pretectum regions, supporting the idea of augmentation of the shh signaling pathway by suppression of foxl1. Expression of zfoxl1-EnR (repressing) rather than zfoxl1-VP16 (activating) resulted in a phenotype similar to that induced by foxl1-mRNA, suggesting that foxl1 may act as a transcriptional repressor of shh in zebra fish embryos. Supporting this notion, foxl1 suppressed isolated 2.7-kb shh promoter activity in PC12 cells, and the minimal region of foxl1 required for its transcriptional repressor activity showed strong homology with the groucho binding motif, which is found in genes encoding various homeodomain proteins. In view of all of our data taken together, we propose zfoxl1 to be a novel regulator of neural development that acts by suppressing shh expression. PMID:16980626

Regulation of fish growth hormone transcription.

PubMed

Farchi-Pisanty, O; Hackett, P B; Moav, B

1995-09-01

Regulation of endogenous fish growth hormone transcription was studied using carp pituitaries in vitro. It was demonstrated that thyroid hormone (T3) and 9-cis retinoic acid have increased the steady state levels of growth hormone messenger RNA in pituitary cells, as compared with beta-actin messenger RNA levels. In contrast, estrogen failed to increase growth hormone mRNA levels. The possible involvement of thyroid hormone receptor in pituitary gene expression was demonstrated by in situ localization of both growth hormone mRNA and thyroid hormone receptor mRNA in the pituitaries as early as 4 days after fertilization.

The characteristics of vasa gene from Japanese sea bass ( Lateolabrax japonicas) and its response to the external hormones

NASA Astrophysics Data System (ADS)

Chi, Meili; Wen, Haishen; Ni, Meng; Qian, Kun; Zhang, Pei; Chai, Senhao

2015-08-01

The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, especially the hormone-related differences in maturing male fish has seldom been documented. In this study, a full length cDNA sequence of the vasa gene was cloned from Japanese sea bass, Lateolabrax japonicas, and it was named jsb-vasa. Homology analysis showed that jsb-vasa was closely related to its teleost homologs. The spatial distribution of jsb-vasa indicated that it was only highly expressed in testis, showing its germ cell-specific expression pattern. During the testicular development cycle, jsb-vasa was highly expressed during early period of spermatogenesis, and reduced when spermatogenesis advanced. In addition, the jsb-vasa gene expression was significantly inhibited at 6 h, 12 h and 24 h after injecting hCG (human chorionic gonadotropin) and GnRHa (Gonadotropin-releasing hormone analogue), indicating that jsb-vasa gene may play an important role in spermatogenesis of Japanese sea bass, and be under the regulation of external sex hormones.

Inhibition of p38 MAPK during cellular activation modulate gene expression of head kidney leukocytes isolated from Atlantic salmon (Salmo salar) fed soy bean oil or fish oil based diets.

PubMed

Holen, E; Winterthun, S; Du, Z-Y; Krøvel, A V

2011-01-01

Head kidney leukocytes isolated from Atlantic salmon fed either a diet based on fish oil (FO) or soy bean oil (VO) were used in order to evaluate if different lipid sources could contribute to cellular activation of the salmon innate immune system. A specific inhibitor of p38 MAPK, SB202190, was used to investigate the effect of lipopolysaccharide (LPS) signalling in the head kidney leukocytes. The results show that LPS up regulate IL-1β, TNF-α, Cox2 expression in leukocytes isolated from fish fed either diet. The p38 MAPK inhibitor, SB202190, reduced the LPS induced expression of these genes in both dietary groups. In LPS stimulated leukocytes isolated from VO fed fish, SB202190 showed a clear dose dependent inhibitory effect on IL-1β, TNF-α and Cox2 expression. This effect was also observed for Cox2 in leukocytes isolated from FO fed fish. Furthermore, there was a stronger mean induction of Cox2 in LPS stimulated leucocytes isolated from the VO-group compared to LPS stimulated leukocytes isolated from the FO-group. In both dietary groups, LPS stimulation of salmon head kidney leukocytes increased the induction of CD83, a dendrite cell marker, while the inhibitor reduced CD83 expression in the VO fed fish only. The inhibitor also clearly reduced hsp27 expression in VO fed fish. Indicating a p38 MAPK feedback loop, LPS significantly inhibited the expression of p38MAPK itself in both diets, while SB202190 increased p38MAPK expression especially in the VO diet group. hsp70 expression was not affected by any treatment or feed composition. There were also differences in p38MAPK protein phosphorylation comparing treatment groups but no obvious difference comparing the two dietary groups. The results indicate that dietary fatty acids have the ability to modify signalling through p38 MAPK which may have consequences for the fish's ability to handle infections and stress. Signalling through p38MAPK is ligand dependent and affects gene and protein expression differently. Copyright © 2010 Elsevier Ltd. All rights reserved.

The effects of acute salinity challenges on osmoregulation in Mozambique tilapia reared in a tidally changing salinity.

PubMed

Moorman, Benjamin P; Lerner, Darren T; Grau, E Gordon; Seale, Andre P

2015-03-01

This study characterizes the differences in osmoregulatory capacity among Mozambique tilapia, Oreochromis mossambicus, reared in freshwater (FW), in seawater (SW) or under tidally driven changes in salinity. This was addressed through the use of an abrupt exposure to a change in salinity. We measured changes in: (1) plasma osmolality and prolactin (PRL) levels; (2) pituitary expression of prolactin (PRL) and its receptors, PRLR1 and PRLR2; (3) branchial expression of PRLR1, PRLR2, Na(+)/Cl(-) co-transporter (NCC), Na(+)/K(+)/2Cl(-) co-transporter (NKCC), α1a and α1b isoforms of Na(+)/K(+)-ATPase (NKA), cystic fibrosis transmembrane conductance regulator (CFTR), aquaporin 3 (AQP3) and Na(+)/H(+) exchanger 3 (NHE3). Mozambique tilapia reared in a tidal environment successfully adapted to SW while fish reared in FW did not survive a transfer to SW beyond the 6 h sampling. With the exception of CFTR, the change in the expression of ion pumps, transporters and channels was more gradual in fish transferred from tidally changing salinities to SW than in fish transferred from FW to SW. Upon transfer to SW, the increase in CFTR expression was more robust in tidal fish than in FW fish. Tidal and SW fish successfully adapted when transferred to FW. These results suggest that Mozambique tilapia reared in a tidally changing salinity, a condition that more closely represents their natural history, gain an adaptive advantage compared with fish reared in FW when facing a hyperosmotic challenge. © 2015. Published by The Company of Biologists Ltd.

Transcriptomic characterization of temperature stress responses in larval zebrafish.

PubMed

Long, Yong; Li, Linchun; Li, Qing; He, Xiaozhen; Cui, Zongbin

2012-01-01

Temperature influences nearly all biochemical, physiological and life history activities of fish, but the molecular mechanisms underlying the temperature acclimation remains largely unknown. Previous studies have identified many temperature-regulated genes in adult tissues; however, the transcriptional responses of fish larvae to temperature stress are not well understood. In this study, we characterized the transcriptional responses in larval zebrafish exposed to cold or heat stress using microarray analysis. In comparison with genes expressed in the control at 28 °C, a total of 2680 genes were found to be affected in 96 hpf larvae exposed to cold (16 °C) or heat (34 °C) for 2 and 48h and most of these genes were expressed in a temperature-specific and temporally regulated manner. Bioinformatic analysis identified multiple temperature-regulated biological processes and pathways. Biological processes overrepresented among the earliest genes induced by temperature stress include regulation of transcription, nucleosome assembly, chromatin organization and protein folding. However, processes such as RNA processing, cellular metal ion homeostasis and protein transport and were enriched in genes up-regulated under cold exposure for 48 h. Pathways such as mTOR signalling, p53 signalling and circadian rhythm were enriched among cold-induced genes, while adipocytokine signalling, protein export and arginine and praline metabolism were enriched among heat-induced genes. Although most of these biological processes and pathways were specifically regulated by cold or heat, common responses to both cold and heat stresses were also found. Thus, these findings provide new interesting clues for elucidation of mechanisms underlying the temperature acclimation in fish.

Effect of Dactylogyrus catlaius (Jain 1961) infection in Labeo rohita (Hamilton 1822): innate immune responses and expression profile of some immune related genes.

PubMed

Dash, Pujarini; Kar, Banya; Mishra, Arpita; Sahoo, P K

2014-03-01

The monogenean ectoparasite, Dactylogyrus sp. is a major pathogen in freshwater aquaculture. The immune responses in parasitized fish were analyzed by quantitation of innate immune factors (natural agglutinin level, haemolysin titre, antiprotease, lysozyme and myeloperoxidase activities) in serum and immune-relevant gene expression in gill and anterior kidney. The antiprotease activity and natural agglutinin level were found to be significantly higher and lysozyme activity was significantly lower in parasitized fish. Most of the genes viz., beta2-microglobulin (beta2M), major histocompatibility complex I (MHCI), MHCII, tumor necrosis factor alpha (TNFalpha) and toll-like receptor 22 (TLR22) in gill samples were significantly down-regulated in the experimental group. In the anterior kidney, the expression of superoxide dismutase and interleukin 1beta (IL1beta) were significantly up-regulated whereas a significant down regulation of MHCII and TNFalpha was also observed. The down-regulation of most of the genes viz, MHCI, beta2M, MHCII, TLR22 and TNFalpha in infected gills indicated a well evolved mechanism in this parasite to escape the host immune response. The modulation of innate and adaptive immunity by this parasite can be further explored to understand host susceptibility.

Small Changes in Gene Expression of Targeted Osmoregulatory Genes When Exposing Marine and Freshwater Threespine Stickleback (Gasterosteus aculeatus) to Abrupt Salinity Transfers

PubMed Central

Taugbøl, Annette; Arntsen, Tina; Østbye, Kjartan; Vøllestad, Leif Asbjørn

2014-01-01

Salinity is one of the key factors that affects metabolism, survival and distribution of fish species, as all fish osmoregulate and euryhaline fish maintain osmotic differences between their extracellular fluid and either freshwater or seawater. The threespine stickleback (Gasterosteus aculeatus) is a euryhaline species with populations in both marine and freshwater environments, where the physiological and genomic basis for salinity tolerance adaptation is not fully understood. Therefore, our main objective in this study was to investigate gene expression of three targeted osmoregulatory genes (Na+/K+-ATPase (ATPA13), cystic fibrosis transmembrane regulator (CFTR) and a voltage gated potassium channel gene (KCNH4) and one stress related heat shock protein gene (HSP70)) in gill tissue from marine and freshwater populations when exposed to non-native salinity for periods ranging from five minutes to three weeks. Overall, the targeted genes showed highly plastic expression profiles, in addition the expression of ATP1A3 was slightly higher in saltwater adapted fish and KCNH4 and HSP70 had slightly higher expression in freshwater. As no pronounced changes were observed in the expression profiles of the targeted genes, this indicates that the osmoregulatory apparatuses of both the marine and landlocked freshwater stickleback population have not been environmentally canalized, but are able to respond plastically to abrupt salinity challenges. PMID:25265477

Small changes in gene expression of targeted osmoregulatory genes when exposing marine and freshwater threespine stickleback (Gasterosteus aculeatus) to abrupt salinity transfers.

PubMed

Taugbøl, Annette; Arntsen, Tina; Ostbye, Kjartan; Vøllestad, Leif Asbjørn

2014-01-01

Salinity is one of the key factors that affects metabolism, survival and distribution of fish species, as all fish osmoregulate and euryhaline fish maintain osmotic differences between their extracellular fluid and either freshwater or seawater. The threespine stickleback (Gasterosteus aculeatus) is a euryhaline species with populations in both marine and freshwater environments, where the physiological and genomic basis for salinity tolerance adaptation is not fully understood. Therefore, our main objective in this study was to investigate gene expression of three targeted osmoregulatory genes (Na+/K+-ATPase (ATPA13), cystic fibrosis transmembrane regulator (CFTR) and a voltage gated potassium channel gene (KCNH4) and one stress related heat shock protein gene (HSP70)) in gill tissue from marine and freshwater populations when exposed to non-native salinity for periods ranging from five minutes to three weeks. Overall, the targeted genes showed highly plastic expression profiles, in addition the expression of ATP1A3 was slightly higher in saltwater adapted fish and KCNH4 and HSP70 had slightly higher expression in freshwater. As no pronounced changes were observed in the expression profiles of the targeted genes, this indicates that the osmoregulatory apparatuses of both the marine and landlocked freshwater stickleback population have not been environmentally canalized, but are able to respond plastically to abrupt salinity challenges.

Development of Cre-loxP technology in zebrafish to study the regulation of fish reproduction.

PubMed

Lin, Heng-Ju; Lee, Shu-Hua; Wu, Jen-Leih; Duann, Yeh-Fang; Chen, Jyh-Yih

2013-12-01

One cannot seek permission to market transgenic fish mainly because there is no field test or any basic research on technological developments for evaluating their biosafety. Infertility is a necessary adjunct to exploiting transgenic fish unless completely secure land-locked facilities are available. In this study, we report the generation of a Cre transgenic zebrafish line using a cytomegalovirus promoter. We also produced fish carrying the Bax1 and Bax2 plasmids; these genes were separated by two loxP sites under a zona pellucida C promoter or were driven by an anti-Müllerian hormone promoter. We inserted a red fluorescent protein gene between the two loxP sites. After obtaining transgenic lines with the two transgenic fish crossed with each other (Cre transgenic zebrafish x loxP transgenic zebrafish), the floxed DNA was found to be specifically eliminated from the female or male zebrafish, and apoptosis gene expressions caused ovarian and testicular growth cessation and degeneration. Overexpression of the Bax1 and Bax2 genes caused various expression levels of apoptosis-related genes. Accordingly, this transgenic zebrafish model system provides a method to produce infertile fish and may be useful for application to genetically modified fish.

Interactive effects of hypoxia and PCB co-exposure on expression of CYP1A and its potential regulators in Atlantic croaker liver.

PubMed

Rahman, Md Saydur; Thomas, Peter

2018-04-01

Although marine and coastal environments which are contaminated with xenobiotic organic compounds often become hypoxic during the summer, the interactive effects of hypoxia and xenobiotic exposure on marine species such as teleost fishes remain poorly understood. The expression and activity of monooxygenase enzyme cytochrome P450-1A (CYP1A) in fishes are upregulated by exposure to polychlorinated biphenyls (PCBs), whereas they are down-regulated during hypoxia exposure. We investigated the interactive effects of hypoxia and PCB co-exposure on hepatic CYP1A expression in Atlantic croaker and on potential regulators of CYP1A. Croaker were exposed to hypoxia (1.7 mg/L dissolved oxygen), 3,3',4,4'-tetrachlorobiphenyl (PCB 77, dose: 2 and 8 µg/g body weight), and Aroclor 1254 (a common PCB mixture, dose: 0.5 and 1 µg/g body weight), alone and in combination for 4 weeks. PCB 77 exposure markedly increased hepatic CYP1A mRNA and protein expression, and ethoxyresorufin-O-deethylase (EROD, an indicator of CYP1A enzyme) activity and increased endothelial nitric oxide synthase (eNOS) protein expression. PCB 77 treatment also increased interleukin-1β (IL-1β, a cytokine) mRNA levels and protein carbonyl (PC, an indicator of reactive oxygen species, ROS) contents. These marked PCB 77- and Aroclor 1254-induced increases in CYP1A mRNA levels and EROD activity were significantly attenuated by co-exposure to hypoxia, whereas the increases in hepatic eNOS protein and IL-1β mRNA expression, and PC contents were augmented by hypoxia co-exposure. The results suggest that biotransformation of organic xenobiotics by CYP1A is reduced in fish during co-exposure to hypoxia and is accompanied by alterations in eNOS, ROS, and IL-1β levels. © 2018 Wiley Periodicals, Inc.

Orthogonal control of expression mean and variance by epigenetic features at different genomic loci

DOE PAGES

Dey, Siddharth S.; Foley, Jonathan E.; Limsirichai, Prajit; ...

2015-05-05

While gene expression noise has been shown to drive dramatic phenotypic variations, the molecular basis for this variability in mammalian systems is not well understood. Gene expression has been shown to be regulated by promoter architecture and the associated chromatin environment. However, the exact contribution of these two factors in regulating expression noise has not been explored. Using a dual-reporter lentiviral model system, we deconvolved the influence of the promoter sequence to systematically study the contribution of the chromatin environment at different genomic locations in regulating expression noise. By integrating a large-scale analysis to quantify mRNA levels by smFISH andmore » protein levels by flow cytometry in single cells, we found that mean expression and noise are uncorrelated across genomic locations. Furthermore, we showed that this independence could be explained by the orthogonal control of mean expression by the transcript burst size and noise by the burst frequency. Finally, we showed that genomic locations displaying higher expression noise are associated with more repressed chromatin, thereby indicating the contribution of the chromatin environment in regulating expression noise.« less

Fibroblast growth factor (Fgf) signaling pathway regulates liver homeostasis in zebrafish.

PubMed

Tsai, Su-Mei; Liu, Da-Wei; Wang, Wen-Pin

2013-04-01

In mammals, fibroblast growth factor (FGF) signaling controls liver specification and regulates the metabolism of lipids, cholesterol, and bile acids. FGF signaling also promotes hepatocyte proliferation, and helps detoxify hepatotoxin during liver regeneration after partial hepatectomy. However, the function of Fgf in zebrafish liver is not yet well understood, specifically for postnatal homeostasis. The current study analyzed the expression of fgf receptors (fgfrs) in the liver of zebrafish. We then investigated the function of Fgf signaling in the zebrafish liver by expressing a dominant-negative Fgf receptor in hepatocytes (lfabp:dnfgfr1-egfp, lf:dnfr). Histological analysis showed that our genetic intervention resulted in a small liver size with defected medial expansion of developing livers in transgenic (Tg) larvae. Morphologically, the liver lobe of lf:dnfr adult fish was shorter than that of control. Ballooning degeneration of hepatocytes was observed in fish as young as 3 months. Further examination revealed the development of hepatic steatosis and cholestasis. In adult Tg fish, we unexpectedly observed increased liver-to-body-weight ratios, with higher percentages of proliferating hepatocytes. Considering all these findings, we concluded that as in mammals, in adult zebrafish the metabolism of lipid and bile acids in the liver are regulated by Fgf signaling. Disruption of the Fgf signal-mediated metabolism might indirectly affect hepatocyte proliferation.

Regulation of the corticosteroid signalling system in rainbow trout HPI axis during confinement stress.

PubMed

Kiilerich, Pia; Servili, Arianna; Péron, Sandrine; Valotaire, Claudiane; Goardon, Lionel; Leguen, Isabelle; Prunet, Patrick

2018-03-01

This study aims to shed light on corticosteroid regulation of stress in teleost fish with focus on the corticosteroid signalling system. The role of the mineralocorticoid-like hormone 11-deoxycorticosterone (DOC) in fish is still enigmatic, as is the function of the mineralocorticoid receptor, MR. Low plasma DOC levels and ubiquitous tissue distribution of MR question the physiological relevance of the mineralocorticoid-axis. Furthermore, the particular purpose of each of the three corticosteroid receptors in fish, the glucocorticoid receptors, GR1 and GR2, and the MR, is still largely unknown. Therefore we investigate the regulation of cortisol and DOC in plasma and mRNA levels of MR, GR1 and GR2 in the HPI-axis tissues (hypothalamus, pituitary and interrenal gland) during a detailed confinement stress time-course. Here we show a sustained up-regulation of plasma DOC levels during a confinement stress time-course. However, the low DOC levels compared to cortisol measured in the plasma do not favour an activity of DOC through MR receptors. Furthermore, we show differential contribution of the CRs in regulation and control of HPI axis activity following confinement stress. Judged by the variation of mRNA levels negative feedback regulation of cortisol release occurs on the level of the pituitary via MR and on the level of the interrenal gland via GR2. Finally, asa significant effect of confinement stress on CR expressions was observed in the pituitary gland, we completed this experiment by demonstrating that corticosteroid receptors (GR1, GR2 and MR) are co-expressed in the ACTH cells located in the adenohypophysis. Overall, these data suggest the involvement of these receptors in the regulation of the HPI axis activity by cortisol. Copyright © 2017 Elsevier Inc. All rights reserved.

Transcriptome analysis demonstrates that long noncoding RNA is involved in the hypoxic response in Larimichthys crocea.

PubMed

Liu, Wei; Liu, Xiaoxu; Wu, Changwen; Jiang, Lihua

2018-06-15

The large yellow croaker (Larimichthys crocea) has low hypoxia tolerance compared with other fish species, and the mRNA levels of hypoxia-inducible factor (HIF)-1α in its brain do not change markedly under hypoxic conditions. In this study, we investigated noncoding transcription in the hypoxic response mechanism of L. crocea. We generated a catalog of long noncoding RNAs (lncRNAs) from the brain of L. crocea individuals under hypoxic stress, investigated lncRNA expression patterns, and analyzed the HIF signaling pathway by RNA sequencing. Prolyl hydroxylase domain 2 (PHD2) expression significantly increased after 6 and 12 h of hypoxia, and a lncRNA (Linc_06633.1) was found in the upstream, antisense region of PHD2. Linc_06633.1 may be an important regulator that promotes PDH2 expression under hypoxia in L. crocea, and we constructed a regulatory profile of L. crocea under hypoxic conditions. To the best of our knowledge, it is the first study that has been conducted on hypoxia signaling pathway regulation by lncRNAs in L. crocea and elucidates the role played by lncRNAs in the regulation of the hypoxia stress response in teleost fish.

The miiuy croaker microRNA transcriptome and microRNA regulation of RIG-I like receptor signaling pathway after poly(I:C) stimulation.

PubMed

Han, Jingjing; Xu, Guoliang; Xu, Tianjun

2016-07-01

MicroRNAs (miRNAs) as endogenous small non-coding RNAs play key regulatory roles in diverse biological processes via degrading the target mRNAs or inhibiting protein translation. Previously many researchers have reported the identification, characteristic of miRNAs and the interaction with its target gene. But, the study on the regulation of miRNAs to biological processes via regulatory the key signaling pathway was still limited. In order to comprehend the regulatory mechanism of miRNAs, two small RNA libraries from the spleen of miiuy croaker individuals with or without poly(I:C) infection were constructed. The 197 conserved miRNAs and 75 novel miRNAs were identified, and 14 conserved and 8 novel miRNAs appeared significant variations. Those differently expressed miRNAs relate to immune regulation of miiuy croaker. Furthermore, expressions of four differently expressed miRNAs were validated by qRT-PCR, and the result was consistent with sequencing data. The target genes of the differently expressed miRNAs in the two libraries were predicted, and some candidate target genes were involved in the RIG-I-like receptor (RLR) signaling pathway. The negative regulation of miRNAs to target genes were confirmed by comparing the expression pattern of miRNAs and their target genes. The results of regulating target genes were that firstly directly or indirectly activating the downstream signaling cascades and subsequent inducting the type I interferon, inflammatory cytokines and apoptosis. These studies could help us to deeper understand the roles of miRNAs played in the fish immune system, and provide a new way to investigate the defense mechanism of fish. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dietary DHA/EPA ratio affected tissue fatty acid profiles, antioxidant capacity, hematological characteristics and expression of lipid-related genes but not growth in juvenile black seabream (Acanthopagrus schlegelii)

PubMed Central

Monroig, Óscar; Lu, You; Yuan, Ye; Li, Yi; Ding, Liyun; Tocher, Douglas R.; Zhou, Qicun

2017-01-01

An 8-week feeding trial was conducted to investigate the effects of dietary docosahexaenoic to eicosapentaenoic acid ratio (DHA/EPA) on growth performance, fatty acid profiles, antioxidant capacity, hematological characteristics and expression of some lipid metabolism related genes of juvenile black seabream (Acanthopagrus schlegelii) of initial weight 9.47 ± 0.03 g. Five isonitrogenous and isolipidic diets (45% crude protein and 14% crude lipid) were formulated to contain graded DHA/EPA ratios of 0.65, 1.16, 1.60, 2.03 and 2.67. There were no differences in growth performance and feed utilization among treatments. Fish fed higher DHA/EPA ratios had higher malondialdehyde (MDA) contents in serum than lower ratios. Serum triacylglycerol (TAG) content was significantly higher in fish fed the lowest DHA/EPA ratio. Tissue fatty acid profiles reflected the diets despite down-regulation of LC-PUFA biosynthesis genes, fatty acyl desaturase 2 (fads2) and elongase of very long-chain fatty acids 5 (elovl5), by high DHA/EPA ratios. Expression of acetyl-CoA carboxylase alpha (accα) and carnitine palmitoyl transferase 1A (cpt1a) were up-regulated by high DHA/EPA ratio, whereas sterol regulatory element-binding protein-1 (srebp-1) and hormone-sensitive lipase (hsl) were down-regulated. Fatty acid synthase (fas), 6-phosphogluconate dehydrogenase (6pgd) and peroxisome proliferator-activated receptor alpha (pparα) showed highest expression in fish fed intermediate (1.16) DHA/EPA ratio. Overall, this study indicated that dietary DHA/EPA ratio affected fatty acid profiles and significantly influenced lipid metabolism including LC-PUFA biosynthesis and other anabolic and catabolic pathways, and also had impacts on antioxidant capacity and hematological characteristics. PMID:28430821

Dietary DHA/EPA ratio affected tissue fatty acid profiles, antioxidant capacity, hematological characteristics and expression of lipid-related genes but not growth in juvenile black seabream (Acanthopagrus schlegelii).

PubMed

Jin, Min; Monroig, Óscar; Lu, You; Yuan, Ye; Li, Yi; Ding, Liyun; Tocher, Douglas R; Zhou, Qicun

2017-01-01

An 8-week feeding trial was conducted to investigate the effects of dietary docosahexaenoic to eicosapentaenoic acid ratio (DHA/EPA) on growth performance, fatty acid profiles, antioxidant capacity, hematological characteristics and expression of some lipid metabolism related genes of juvenile black seabream (Acanthopagrus schlegelii) of initial weight 9.47 ± 0.03 g. Five isonitrogenous and isolipidic diets (45% crude protein and 14% crude lipid) were formulated to contain graded DHA/EPA ratios of 0.65, 1.16, 1.60, 2.03 and 2.67. There were no differences in growth performance and feed utilization among treatments. Fish fed higher DHA/EPA ratios had higher malondialdehyde (MDA) contents in serum than lower ratios. Serum triacylglycerol (TAG) content was significantly higher in fish fed the lowest DHA/EPA ratio. Tissue fatty acid profiles reflected the diets despite down-regulation of LC-PUFA biosynthesis genes, fatty acyl desaturase 2 (fads2) and elongase of very long-chain fatty acids 5 (elovl5), by high DHA/EPA ratios. Expression of acetyl-CoA carboxylase alpha (accα) and carnitine palmitoyl transferase 1A (cpt1a) were up-regulated by high DHA/EPA ratio, whereas sterol regulatory element-binding protein-1 (srebp-1) and hormone-sensitive lipase (hsl) were down-regulated. Fatty acid synthase (fas), 6-phosphogluconate dehydrogenase (6pgd) and peroxisome proliferator-activated receptor alpha (pparα) showed highest expression in fish fed intermediate (1.16) DHA/EPA ratio. Overall, this study indicated that dietary DHA/EPA ratio affected fatty acid profiles and significantly influenced lipid metabolism including LC-PUFA biosynthesis and other anabolic and catabolic pathways, and also had impacts on antioxidant capacity and hematological characteristics.

Gene Expression Changes Related to Endocrine Function and Decline in Reproduction in Fathead Minnow (Pimephales promelas) after Dietary Methylmercury Exposure

PubMed Central

Klaper, Rebecca; Rees, Christopher B.; Drevnick, Paul; Weber, Daniel; Sandheinrich, Mark; Carvan, Michael J.

2006-01-01

Background Methylmercury (MeHg) is a known neurotoxic agent, but the mechanisms by which MeHg may act on reproductive pathways are relatively unknown. Several studies have indicated potential changes in hormone levels as well as declines in vertebrates with increasing dietary MeHg exposure. Objectives The purpose of this study was to identify alterations in gene expression associated with MeHg exposure, specifically those associated with previously observed changes in reproduction and reproductive biomarkers. Fathead minnows, Pimephales promelas, were fed one of three diets that were similar to documented concentrations of MeHg in the diets of wild invertivorous and piscivorous fish. We used a commercial macroarray in conjunction with quantitative polymerase chain reaction to examine gene expression in fish in relation to exposure to these environmentally relevant doses of MeHg. Results Expression of genes commonly associated with endocrine disruption was altered with Hg exposure. Specifically, we observed a marked up-regulation in vitellogenin mRNA in individual Hg-exposed males and a significant decline in vitellogenin gene expression in female fish with increasing Hg concentrations. Other genes identified by the macroarray experiment included those associated with egg fertilization and development, sugar metabolism, apoptosis, and electron transport. We also observed differences in expression patterns between male and female fish not related to genes specifically associated with reproduction, indicating a potential physiological difference in the reaction of males and females to MeHg. Conclusion Gene expression data may provide insight into the mechanisms by which MeHg affects reproduction in fish and indicate how MeHg differs in its effect from other heavy metals and endocrine-disrupting compounds. PMID:16966085

Acute stress alters transcript expression pattern and reduces processing of proBDNF to mature BDNF in Dicentrarchus labrax

PubMed Central

2010-01-01

Background Stress involves alterations of brain functioning that may precipitate to mood disorders. The neurotrophin Brain Derived Neurotrophic Factor (BDNF) has recently been involved in stress-induced adaptation. BDNF is a key regulator of neuronal plasticity and adaptive processes. Regulation of BDNF is complex and may reflect not only stress-specific mechanisms but also hormonal and emotional responses. For this reason we used, as an animal model of stress, a fish whose brain organization is very similar to that of higher vertebrates, but is generally considered free of emotional reactions. Results We provide a comprehensive characterization of BDNF gene in the Dicentrarchus labrax and its transcriptional, translational and post-translational regulation following acute stress. While total BDNF mRNA levels are unchanged, BDNF transcripts 1c and 1d resulted down regulated after acute stress. Acute stress induces also a significant increase in proBDNF levels and reduction in mature BDNF suggesting altered regulation of proBDNF proteolytic processing. Notably, we provide here the first evidence that fishes possess a simplified proteolytic regulation of BDNF since the pro28Kda form, generated by the SKI-1 protease in mammals, is absent in fishes because the cleavage site has first emerged in reptilians. Finally, we show that the proBDNF/totBDNF ratio is a highly predictive novel quantitative biomarker to detect stress in fishes with sensitivity = 100%, specificity = 87%, and Negative Predictive Value = 100%. Conclusion The high predictivity of proBDNF/totBDNF ratio for stress in lower vertebrates indicates that processing of BDNF is a central mechanism in adaptation to stress and predicts that a similar regulation of pro/mature BDNF has likely been conserved throughout evolution of vertebrates from fish to man. PMID:20074340

Acute stress alters transcript expression pattern and reduces processing of proBDNF to mature BDNF in Dicentrarchus labrax.

PubMed

Tognoli, Chiara; Rossi, Federica; Di Cola, Francesco; Baj, Gabriele; Tongiorgi, Enrico; Terova, Genciana; Saroglia, Marco; Bernardini, Giovanni; Gornati, Rosalba

2010-01-14

Stress involves alterations of brain functioning that may precipitate to mood disorders. The neurotrophin Brain Derived Neurotrophic Factor (BDNF) has recently been involved in stress-induced adaptation. BDNF is a key regulator of neuronal plasticity and adaptive processes. Regulation of BDNF is complex and may reflect not only stress-specific mechanisms but also hormonal and emotional responses. For this reason we used, as an animal model of stress, a fish whose brain organization is very similar to that of higher vertebrates, but is generally considered free of emotional reactions. We provide a comprehensive characterization of BDNF gene in the Dicentrarchus labrax and its transcriptional, translational and post-translational regulation following acute stress. While total BDNF mRNA levels are unchanged, BDNF transcripts 1c and 1d resulted down regulated after acute stress. Acute stress induces also a significant increase in proBDNF levels and reduction in mature BDNF suggesting altered regulation of proBDNF proteolytic processing. Notably, we provide here the first evidence that fishes possess a simplified proteolytic regulation of BDNF since the pro28Kda form, generated by the SKI-1 protease in mammals, is absent in fishes because the cleavage site has first emerged in reptilians. Finally, we show that the proBDNF/totBDNF ratio is a highly predictive novel quantitative biomarker to detect stress in fishes with sensitivity = 100%, specificity = 87%, and Negative Predictive Value = 100%. The high predictivity of proBDNF/totBDNF ratio for stress in lower vertebrates indicates that processing of BDNF is a central mechanism in adaptation to stress and predicts that a similar regulation of pro/mature BDNF has likely been conserved throughout evolution of vertebrates from fish to man.

Inducible MicroRNA-3570 Feedback Inhibits the RIG-I-Dependent Innate Immune Response to Rhabdovirus in Teleost Fish by Targeting MAVS/IPS-1.

PubMed

Xu, Tianjun; Chu, Qing; Cui, Junxia; Bi, Dekun

2018-01-15

Effectively recognizing invading viruses and subsequently inducing innate antiviral immunity are essential for host antiviral defense. Although these processes are closely regulated by the host to maintain immune balance, viruses have evolved the ability to downregulate or upregulate these processes for their survival. MicroRNAs (miRNAs) are a family of small noncoding RNAs that play vital roles in modulating host immune response. Accumulating evidence demonstrates that host miRNAs as mediators are involved in regulating viral replication and host antiviral immunity in mammals. However, the underlying regulatory mechanisms in fish species are still poorly understood. Here, we found that rhabdovirus infection significantly upregulated host miR-3570 expression in miiuy croaker macrophages. Induced miR-3570 negatively modulated RNA virus-triggered type I interferon (IFN) and antiviral gene production, thus facilitating viral replication. Furthermore, miR-3570 was found to target and posttranscriptionally downregulate mitochondrial antiviral signaling protein (MAVS), which functions as a platform for innate antiviral signal transduction. Moreover, we demonstrated that miR-3570 suppressed the expression of MAVS, thereby inhibiting MAVS-mediated NF-κB and IRF3 signaling. The collective results demonstrated a novel regulation mechanism of MAVS-mediated immunity during RNA viral infection by miRNA. IMPORTANCE RNA viral infection could upregulate host miR-3570 expression in miiuy croaker macrophages. Induced miR-3570 negatively modulates RNA virus-triggered type I IFN and antiviral gene production, thus facilitating viral replication. Remarkably, miR-3570 could target and inhibit MAVS expression, which thus modulates MAVS-mediated NF-κB and IRF3 signaling. The collective results of this study suggest a novel regulation mechanism of MAVS-mediated immunity during RNA viral infection by miR-3570. Thus, a novel mechanism for virus evasion in fish is proposed. Copyright © 2018 American Society for Microbiology.

BAC Recombineering of the Agouti Loci from Spotted Gar and Zebrafish Reveals the Evolutionary Ancestry of Dorsal-Ventral Pigment Asymmetry in Fish.

PubMed

Cal, Laura; MegÍas, Manuel; Cerdá-Reverter, José Miguel; Postlethwait, John H; Braasch, Ingo; Rotllant, Josep

2017-11-01

Dorsoventral pigment patterning, characterized by a light ventrum and a dark dorsum, is one of the most widespread chromatic adaptations in vertebrate body coloration. In mammals, this countershading depends on differential expression of agouti-signaling protein (ASIP), which drives a switch of synthesis of one type of melanin to another within melanocytes. Teleost fish share countershading, but the pattern results from a differential distribution of multiple types of chromatophores, with black-brown melanophores most abundant in the dorsal body and reflective iridophores most abundant in the ventral body. We previously showed that Asip1 (a fish ortholog of mammalian ASIP) plays a role in patterning melanophores. This observation leads to the surprising hypothesis that agouti may control an evolutionarily conserved pigment pattern by regulating different mechanisms in mammals and fish. To test this hypothesis, we compared two ray-finned fishes: the teleost zebrafish and the nonteleost spotted gar (Lepisosteus oculatus). By examining the endogenous pattern of asip1 expression in gar, we demonstrate a dorsoventral-graded distribution of asip1 expression that is highest ventrally, similar to teleosts. Additionally, in the first reported experiments to generate zebrafish transgenic lines carrying a bacterial artificial chromosome (BAC) from spotted gar, we show that both transgenic zebrafish lines embryos replicate the endogenous asip1 expression pattern in adult zebrafish, showing that BAC transgenes from both species contain all of the regulatory elements required for regular asip1 expression within adult ray-finned fishes. These experiments provide evidence that the mechanism leading to an environmentally important pigment pattern was likely in place before the origin of teleosts. © 2017 Wiley Periodicals, Inc.

Molecular cloning, characterization and functional analysis of QRFP in orange-spotted grouper (Epinephelus coioides).

PubMed

Shu, Hu; Chen, Huapu; Liu, Yun; Yang, Lidong; Yang, Yuqing; Zhang, Haifa

2014-10-01

The peptide QRFP plays an important role in the regulation of vertebrate feeding behavior. In this study, we cloned the full length cDNA of a QRFP precursor in a teleost fish, the orange-spotted grouper (Epinephelus coioides). Sequence analysis has shown that the functional regions of QRFP in other vertebrates (QRFP-25 and QRFP-7) are conserved in orange-spotted grouper. RT-PCR demonstrated that the pre-processed mRNA of QRFP is widely expressed in orange-spotted grouper. Three days of food deprivation did not change the hypothalamic pre-processed QRFP expression. However, QRFP expression significantly increased when the fish were reefed after three days of fasting. Intraperitoneal injection of QRFP-25 peptide to orange-spotted grouper suppressed expression of orexin, but elevated expression of pro-opiomelanocortin (POMC) in the hypothalamus. We also investigated the effects of QRFP-25 on the expression of reproductive genes. The peptide suppressed the expression of seabream-type gonadotropin-releasing hormones (sbGnRH), luteinizing hormone beta subunit (LHβ) and follicle-stimulating hormone beta subunit (FSHβ) in vivo, as well as inhibited the expression of LHβ and FSHβ in pituitary cells in primary culture. Our results indicate that QRFP may play an inhibitory role in the regulation of feeding behavior and reproduction in orange-spotted grouper. Copyright © 2014 Elsevier Inc. All rights reserved.

RNAseq analysis of fast skeletal muscle in restriction-fed transgenic coho salmon (Oncorhynchus kisutch): an experimental model uncoupling the growth hormone and nutritional signals regulating growth.

PubMed

Garcia de la Serrana, Daniel; Devlin, Robert H; Johnston, Ian A

2015-07-31

Coho salmon (Oncorhynchus kisutch) transgenic for growth hormone (Gh) express Gh in multiple tissues which results in increased appetite and continuous high growth with satiation feeding. Restricting Gh-transgenics to the same lower ration (TR) as wild-type fish (WT) results in similar growth, but with the recruitment of fewer, larger diameter, muscle skeletal fibres to reach a given body size. In order to better understand the genetic mechanisms behind these different patterns of muscle growth and to investigate how the decoupling of Gh and nutritional signals affects gene regulation we used RNA-seq to compare the fast skeletal muscle transcriptome in TR and WT coho salmon. Illumina sequencing of individually barcoded libraries from 6 WT and 6 TR coho salmon yielded 704,550,985 paired end reads which were used to construct 323,115 contigs containing 19,093 unique genes of which >10,000 contained >90 % of the coding sequence. Transcripts coding for 31 genes required for myoblast fusion were identified with 22 significantly downregulated in TR relative to WT fish, including 10 (vaspa, cdh15, graf1, crk, crkl, dock1, trio, plekho1a, cdc42a and dock5) associated with signaling through the cell surface protein cadherin. Nineteen out of 44 (43 %) translation initiation factors and 14 of 47 (30 %) protein chaperones were upregulated in TR relative to WT fish. TR coho salmon showed increased growth hormone transcripts and gene expression associated with protein synthesis and folding than WT fish even though net rates of protein accretion were similar. The uncoupling of Gh and amino acid signals likely results in additional costs of transcription associated with protein turnover in TR fish. The predicted reduction in the ionic costs of homeostasis in TR fish associated with increased fibre size were shown to involve multiple pathways regulating myotube fusion, particularly cadherin signaling.

Distinct functions of neuromedin u and neuromedin s in orange-spotted grouper.

PubMed

Li, Shuisheng; Xiao, Ling; Liu, Qiongyu; Zheng, Binbin; Chen, Huapu; Liu, Xiaochun; Zhang, Yong; Lin, Haoran

2015-10-01

Neuromedin U (NMU) and neuromedin S (NMS) play inhibitory roles in the regulation of food intake and energy homeostasis in mammals. However, their functions are not clearly established in teleost fish. In the present study, nmu and nms homologs were identified in several fish species. Subsequently, their cDNA sequences were cloned from the orange-spotted grouper (Epinephelus coioides). Sequence analysis showed that the orange-spotted grouper Nmu proprotein contains a 21-amino acid mature Nmu peptide (Nmu-21). The Nms proprotein lost the typical mature Nms peptide, but it retains a putative 34-amino acid peptide (Nmsrp). In situ hybridization revealed that nmu- and nms-expressing cells are mainly localized in the hypothalamic regions associated with appetite regulation. Food deprivation decreased the hypothalamic nmu mRNA levels but induced an increase of nms mRNA levels. Periprandial expression analysis showed that hypothalamic expression of nmu increased significantly at 3 h post-feeding, while nms expression was elevated at the normal feeding time. I.p. injection of synthetic Nmu-21 peptide suppressed the hypothalamic neuropeptide y (npy) expression, while Nmsrp administration significantly increased the expression of npy and orexin in orange-spotted grouper. Furthermore, the mRNA levels of LH beta subunit (lhβ) and gh in the pituitary were significantly down-regulated after Nmu-21 peptide administration, while Nmsrp was able to significantly stimulate the expression of FSH beta subunit (fshβ), prolactin (prl), and somatolaction (sl). Our results indicate that nmu and nms possess distinct neuroendocrine functions and pituitary functions in the orange spotted grouper. © 2015 Society for Endocrinology.

Profiles of gonadotropin-inhibitory hormone and melatonin during the sex change and maturation of cinnamon clownfish, Amphiprion melanopus.

PubMed

Choi, Young Jae; Habibi, Hamid R; Choi, Cheol Young

2016-06-24

The present study aimed to determine the relationship between melatonin and gonadotropin-inhibitory hormone (GnIH) and their effect on reproduction in cinnamon clownfish, Amphiprion melanopus. Accordingly, we investigated the expression pattern of GnIH, GnIH receptor (GnIH-R), and melatonin receptor (MT-R1) mRNA and protein, as well as the plasma levels of melatonin, during sex change in cinnamon clownfish. We found that GnIH and MT-R1 mRNA and melatonin activity were higher in fish with mature brain than in fish with developing gonads, and using double immunofluorescence staining, we found that both GnIH and MT-R1 proteins were co-expressed in the hypothalamus of cinnamon clownfish. These findings support the hypothesis that melatonin plays an important role in the negative regulation of maturation and GnIH regulation during reproduction. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of the UV filter benzophenone-3 (oxybenzone) at low concentrations in zebrafish (Danio rerio)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blüthgen, Nancy; University of Basel, Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, Klingelbergstrasse 50, CH-4056 Basel; Zucchi, Sara

Organic UV filters including benzophenone-3 (BP-3) are widely used to protect humans and materials from damage by UV irradiation. Despite the environmental occurrence of BP-3 in the aquatic environment, little is known about its effects and modes of action. In the present study we assess molecular and physiological effects of BP-3 in adult male zebrafish (Danio rerio) and in eleuthero-embryos by a targeted gene expression approach focusing on the sex hormone system. Fish and embryos are exposed for 14 days and 120 hours post fertilization, respectively, to 2.4–312 μg/L and 8.2–438 μg/L BP-3. Chemical analysis of water and fish demonstratesmore » that BP-3 is partly transformed to benzophenone-1 (BP-1) and both compounds are accumulated in adult fish. Biotransformation to BP-1 is absent in eleuthero-embryos. BP-3 exposure leads to similar alterations of gene expression in both adult fish and eleuthero-embryos. In the brain of adult males esr1, ar and cyp19b are down-regulated at 84 μg/L BP-3. There is no induction of vitellogenin expression by BP-3, both at the transcriptional and protein level. An overall down-regulation of the hsd3b, hsd17b3, hsd11b2 and cyp11b2 transcripts is observed in the testes, suggesting an antiandrogenic activity. No histological changes were observed in the testes after BP-3 treatment. The study leads to the conclusion that low concentrations of BP-3 exhibit similar multiple hormonal activities at the transcription level in two different life stages of zebrafish. Forthcoming studies should show whether this translates to additional physiological effects. Highlights: ► Activity of UV filter benzophenone-3 (BP-3) is assessed in zebrafish. ► BP-3 is partly metabolized to benzophenone-1 by adult fish but not embryos. ► Alterations of gene expression are similar in adult males and embryos. ► Gene expression alterations point to multiple hormonal activity of BP-3.« less

Mugilid Fish Are Sentinels of Exposure to Endocrine Disrupting Compounds in Coastal and Estuarine Environments

PubMed Central

Ortiz-Zarragoitia, Maren; Bizarro, Cristina; Rojo-Bartolomé, Iratxe; Diaz de Cerio, Oihane; Cajaraville, Miren P.; Cancio, Ibon

2014-01-01

Effects on fish reproduction can result from a variety of toxicity mechanisms first operating at the molecular level. Notably, the presence in the environment of some compounds termed endocrine disrupting chemicals (EDCs) can cause adverse effects on reproduction by interfering with the endocrine system. In some cases, exposure to EDCs leads to the animal feminization and male fish may develop oocytes in testis (intersex condition). Mugilid fish are well suited sentinel organisms to study the effects of reproductive EDCs in the monitoring of estuarine/marine environments. Up-regulation of aromatases and vitellogenins in males and juveniles and the presence of intersex individuals have been described in a wide array of mullet species worldwide. There is a need to develop new molecular markers to identify early feminization responses and intersex condition in fish populations, studying mechanisms that regulate gonad differentiation under exposure to xenoestrogens. Interestingly, an electrophoresis of gonad RNA, shows a strong expression of 5S rRNA in oocytes, indicating the potential of 5S rRNA and its regulating proteins to become useful molecular makers of oocyte presence in testis. Therefore, the use of these oocyte markers to sex and identify intersex mullets could constitute powerful molecular biomarkers to assess xenoestrogenicity in field conditions. PMID:25222666

Responses of neurogenesis and neuroplasticity related genes to elevated CO2 levels in the brain of three teleost species.

PubMed

Lai, Floriana; Fagernes, Cathrine E; Bernier, Nicholas J; Miller, Gabrielle M; Munday, Philip L; Jutfelt, Fredrik; Nilsson, Göran E

2017-08-01

The continuous increase of anthropogenic CO 2 in the atmosphere resulting in ocean acidification has been reported to affect brain function in some fishes. During adulthood, cell proliferation is fundamental for fish brain growth and for it to adapt in response to external stimuli, such as environmental changes. Here we report the first expression study of genes regulating neurogenesis and neuroplasticity in brains of three-spined stickleback ( Gasterosteus aculeatus ), cinnamon anemonefish ( Amphiprion melanopus ) and spiny damselfish ( Acanthochromis polyacanthus ) exposed to elevated CO 2 The mRNA expression levels of the neurogenic differentiation factor (NeuroD) and doublecortin (DCX) were upregulated in three-spined stickleback exposed to high-CO 2 compared with controls, while no changes were detected in the other species. The mRNA expression levels of the proliferating cell nuclear antigen (PCNA) and the brain-derived neurotrophic factor (BDNF) remained unaffected in the high-CO 2 exposed groups compared to the control in all three species. These results indicate a species-specific regulation of genes involved in neurogenesis in response to elevated ambient CO 2 levels. The higher expression of NeuroD and DCX mRNA transcripts in the brain of high-CO 2 -exposed three-spined stickleback, together with the lack of effects on mRNA levels in cinnamon anemonefish and spiny damselfish, indicate differences in coping mechanisms among fish in response to the predicted-future CO 2 level. © 2017 The Author(s).

Complete depletion of primordial germ cells in an All-female fish leads to Sex-biased gene expression alteration and sterile All-male occurrence.

PubMed

Liu, Wei; Li, Shi-Zhu; Li, Zhi; Wang, Yang; Li, Xi-Yin; Zhong, Jian-Xiang; Zhang, Xiao-Juan; Zhang, Jun; Zhou, Li; Gui, Jian-Fang

2015-11-18

Gynogenesis is one of unisexual reproduction modes in vertebrates, and produces all-female individuals with identical genetic background. In sexual reproduction vertebrates, the roles of primordial germ cells on sexual dimorphism and gonadal differentiation have been largely studied, and two distinct functional models have been proposed. However, the role of primordial germ cells remains unknown in unisexual animals, and it is also unclear whether the functional models in sexual reproduction animals are common in unisexual animals. To solve these puzzles, we attempt to utilize the gynogenetic superiority of polyploid Carassius gibelio to create a complete germ cell-depleted gonad model by a similar morpholino-mediated knockdown approach used in other examined sexual reproduction fishes. Through the germ cell-depleted gonad model, we have performed comprehensive and comparative transcriptome analysis, and revealed a complete alteration of sex-biased gene expression. Moreover, the expression alteration leads to up-regulation of testis-biased genes and down-regulation of ovary-biased genes, and results in the occurrence of sterile all-males with testis-like gonads and secondary sex characteristics in the germ cell-depleted gynogenetic Carassius gibelio. Our current results have demonstrated that unisexual gynogenetic embryos remain keeping male sex determination information in the genome, and the complete depletion of primordial germ cells in the all-female fish leads to sex-biased gene expression alteration and sterile all-male occurrence.

Local and systemic gene expression responses of Atlantic salmon (Salmo salar L.) to infection with the salmon louse (Lepeophtheirus salmonis)

PubMed Central

Skugor, Stanko; Glover, Kevin Alan; Nilsen, Frank; Krasnov, Aleksei

2008-01-01

Background The salmon louse (SL) is an ectoparasitic caligid crustacean infecting salmonid fishes in the marine environment. SL represents one of the major challenges for farming of salmonids, and veterinary intervention is necessary to combat infection. This study addressed gene expression responses of Atlantic salmon infected with SL, which may account for its high susceptibility. Results The effects of SL infection on gene expression in Atlantic salmon were studied throughout the infection period from copepodids at 3 days post infection (dpi) to adult lice (33 dpi). Gene expression was analyzed at three developmental stages in damaged and intact skin, spleen, head kidney and liver, using real-time qPCR and a salmonid cDNA microarray (SFA2). Rapid detection of parasites was indicated by the up-regulation of immunoglobulins in the spleen and head kidney and IL-1 receptor type 1, CD4, beta-2-microglobulin, IL-12β, CD8α and arginase 1 in the intact skin of infected fish. Most immune responses decreased at 22 dpi, however, a second activation was observed at 33 dpi. The observed pattern of gene expression in damaged skin suggested the development of inflammation with signs of Th2-like responses. Involvement of T cells in responses to SL was witnessed with up-regulation of CD4, CD8α and programmed death ligand 1. Signs of hyporesponsive immune cells were seen. Cellular stress was prevalent in damaged skin as seen by highly significant up-regulation of heat shock proteins, other chaperones and mitochondrial proteins. Induction of the major components of extracellular matrix, TGF-β and IL-10 was observed only at the adult stage of SL. Taken together with up-regulation of matrix metalloproteinases (MMP), this classifies the wounds afflicted by SL as chronic. Overall, the gene expression changes suggest a combination of chronic stress, impaired healing and immunomodulation. Steady increase of MMP expression in all tissues except liver was a remarkable feature of SL infected fish. Conclusion SL infection in Atlantic salmon is associated with a rapid induction of mixed inflammatory responses, followed by a period of hyporesponsiveness and delayed healing of injuries. Persistent infection may lead to compromised host immunity and tissue self-destruction. PMID:18945374

A comparative examination of cortisol effects on muscle myostatin and HSP90 gene expression in salmonids.

PubMed

Galt, Nicholas J; McCormick, Stephen D; Froehlich, Jacob Michael; Biga, Peggy R

2016-10-01

Cortisol, the primary corticosteroid in teleost fishes, is released in response to stressors to elicit local functions, however little is understood regarding muscle-specific responses to cortisol in these fishes. In mammals, glucocorticoids strongly regulate the muscle growth inhibitor, myostatin, via glucocorticoid response elements (GREs) leading to muscle atrophy. Bioinformatics methods suggest that this regulatory mechanism is conserved among vertebrates, however recent evidence suggests some fishes exhibit divergent regulation. Therefore, the aim of this study was to evaluate the conserved actions of cortisol on myostatin and hsp90 expression to determine if variations in cortisol interactions have emerged in salmonid species. Representative salmonids; Chinook salmon (Oncorhynchus tshawytscha), cutthroat trout (Oncorhynchus clarki), brook trout (Salvelinus fontinalis), and Atlantic salmon (Salmo salar); were injected intraperitoneally with a cortisol implant (50μg/g body weight) and muscle gene expression was quantified after 48h. Plasma glucose and cortisol levels were significantly elevated by cortisol in all species, demonstrating physiological effectiveness of the treatment. HSP90 mRNA levels were elevated by cortisol in brook trout, Chinook salmon, and Atlantic salmon, but were decreased in cutthroat trout. Myostatin mRNA levels were affected in a species, tissue (muscle type), and paralog specific manner. Cortisol treatment increased myostatin expression in brook trout (Salvelinus) and Atlantic salmon (Salmo), but not in Chinook salmon (Oncorhynchus) or cutthroat trout (Oncorhynchus). Interestingly, the VC alone increased myostatin mRNA expression in Chinook and Atlantic salmon, while the addition of cortisol blocked the response. Taken together, these results suggest that cortisol affects muscle-specific gene expression in species-specific manners, with unique Oncorhynchus-specific divergence observed, that are not predictive solely based upon mammalian stress responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Brain cortisol receptor expression differs in Arctic charr displaying opposite coping styles.

PubMed

Vindas, Marco A; Magnhagen, Carin; Brännäs, Eva; Øverli, Øyvind; Winberg, Svante; Nilsson, Jan; Backström, Tobias

2017-08-01

Individually consistent behavioral and physiological responses to stressful situations (often referred to as coping styles) has been reported in many animal species. Differences in hypothalamic-pituitary axis reactivity characterize individuals, and it has been proposed that the glucocorticoid (gr) and mineralocorticoid (mr) receptors are fundamental in regulating coping styles. We sorted individuals into reactive and proactive coping styles by collapsing behavioral outputs from net restraint and confinement stress tests in a principal component analysis. We then analyzed plasma cortisol levels, serotonin neurochemistry and the relative mRNA expression of gr1 and mr in stressed individuals per coping style. Proactive fish were characterized as having a lower serotonergic activity and being more active under stress. In addition, proactive fish had higher hypothalamic gr1 and mr abundance and a higher mr/gr1 ratio, compared to reactive fish. We found no significant differences in cortisol or telencephalic mRNA, gr1 and mr expression, or their ratio. Brain MR and GR have been proven to have an important role in the appraisal, coping and adaptation to stressful stimuli, so that a higher expression of these receptors in proactive fish suggests increased tolerance and performance under stress, compared to reactive individuals. We present evidence of a conserved neuroendocrine mechanism associated with coping styles in a fish species which is ecologically very diverse and considered to be the most cold-adapted fish in freshwater. We propose that this may be a first step into exploiting this model in order to better understand climate-change related effects in sub populations and ecophenotypes. Copyright © 2017 Elsevier Inc. All rights reserved.

Dietary carbohydrates induce changes in glucosensing capacity and food intake of rainbow trout.

PubMed

Polakof, Sergio; Míguez, Jesús M; Soengas, José L

2008-08-01

We hypothesize that variations in dietary carbohydrate levels produce changes in glucosensor parameters in previously characterized glucosensing areas (hypothalamus and hindbrain) related with the regulation of food intake of a carnivorous fish species like rainbow trout. Therefore, we fed trout with standard, carbohydrate-free (CF) or high-carbohydrate (HC) diets for 10 days to assess changes in glucosensing system and food intake. Fish fed CF diet displayed hypoglycemia and increased food intake. Fish fed a HC diet displayed hyperglycemia and decreased food intake. Changes in food intake due to dietary carbohydrates were accompanied in hypothalamus and hindbrain of fish fed with HC diet by changes in parameters involved in glucosensing, such as increased glucose, glucose 6-phosphate, and glycogen levels and increased glucokinase (GK), glycogen synthase, and pyruvate kinase activities as well as increased GK and GLUT2 expression. All those results address for the first time in fish, despite the relative intolerance to glucose of carnivorous species, that dietary carbohydrates are important regulators of the glucosensing system in carnivorous fish, suggesting that the information generated by this system can be associated with the changes observed in food intake.

Molecular biology and physiology of the melanocortin system in fish: a review.

PubMed

Metz, Juriaan R; Peters, Joris J M; Flik, Gert

2006-09-01

The melanocortin system consists of melanocortin peptides derived from the proopiomelanocortin gene (in particular adrenocorticotropic hormone, ACTH, and melanocyte-stimulating hormones, MSH) and five melanocortin receptor subtypes (MC1R-MC5R). Knowledge of the melanocortin system in fish is still limited, but information on the receptor part of the system is very rapidly growing. The melanocortin receptors (MCRs) have been recently cloned from several species of fish. The amino acid sequences appear remarkably well conserved. Pharmacological characterisation studies of the first identified piscine MCRs indicate that ACTH may be the original ligand for the MCRs, while the MSH peptides gained specialised functions in the course of evolution. Considering the tissue distribution of the MCRs, there are two distinctions between mammals and fish: where in mammals the MC4R is exclusively expressed in the central nervous system, in the fish species examined so far it is also peripherally expressed. It does however, alike the situation in mammals, likely play a key role in the central regulation of food intake and energy balance. Not only the MCRs, but also many other factors involved herewith, have been found in fish and roughly appear to function similarly as in mammals. The second difference is the distribution of the MC5R, which appears less widely expressed in fish than in mammals. Considering the available data it is predicted that, in mammals and fish alike, skin colouration is mediated via MC1R and steroidogenesis via MC2R. This review provides a short overview of the basic molecular characteristics, pharmacology, and tissue distribution of the MCRs in the fish investigated up to now, as well as their physiological role in the processes of skin colouration, steroidogenesis, and feeding behaviour.

Fish oil alleviated high-fat diet-induced non-alcoholic fatty liver disease via regulating hepatic lipids metabolism and metaflammation: a transcriptomic study.

PubMed

Yuan, Fahu; Wang, Hualin; Tian, Yu; Li, Qi; He, Lei; Li, Na; Liu, Zhiguo

2016-02-01

Intake of fish oil rich in n-3 polyunsaturated fatty acids (PUFAs) is believed to be beneficial against development of non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms remain unclear. This study was to gain further understanding of the potential mechanisms of the protective effects of fish oil against NAFLD. Ten male Sprague-Dawley rats were fed a control diet (CON), a Western style high-fat and high-cholesterol diet (WD), or a WD diet containing fish oil (FOH) for 16 weeks respectively. The development of liver steatosis and fibrosis were verified by histological and biochemical examination. Hepatic transcriptome were extracted for RNA-seq analysis, and particular results were confirmed by real-time polymerase chain reaction (PCR). The consumption of fish oil significantly ameliorated WD-induced dyslipidemia, transaminase elevation, hepatic steatosis, inflammatory infiltration, and fibrosis. Hepatic RNA-Seq analysis showed that long-term intake of fish oil restored the expression of circadian clock-related genes per2 and per3, which were reduced in WD fed animals. Fish oil consumption also corrected the expression levels of genes involved in fatty acid and cholesterol metabolism, such as Srebf1, Fasn, Scd1, Insig2, Cd36, Cyp7a1, Abcg5, Abcg8 and Pcsk9. Moreover, the expression levels of pro-inflammation genes Mcp1, Socs2, Sema4a, and Cd44 in the FOH group were lower than that of WD group, implying that fish oil protects the liver against WD-induced hepatic inflammation. The present study demonstrates fish oil protects against WD-induced NALFD via improving lipid metabolism and ameliorating hepatic inflammation. Our findings add to the current understanding on the benefits of n-3 PUFAs against NAFLD.

Combined DNA-RNA Fluorescent In situ Hybridization (FISH) to Study X Chromosome Inactivation in Differentiated Female Mouse Embryonic Stem Cells

PubMed Central

Barakat, Tahsin Stefan; Gribnau, Joost

2014-01-01

Fluorescent in situ hybridization (FISH) is a molecular technique which enables the detection of nucleic acids in cells. DNA FISH is often used in cytogenetics and cancer diagnostics, and can detect aberrations of the genome, which often has important clinical implications. RNA FISH can be used to detect RNA molecules in cells and has provided important insights in regulation of gene expression. Combining DNA and RNA FISH within the same cell is technically challenging, as conditions suitable for DNA FISH might be too harsh for fragile, single stranded RNA molecules. We here present an easily applicable protocol which enables the combined, simultaneous detection of Xist RNA and DNA encoded by the X chromosomes. This combined DNA-RNA FISH protocol can likely be applied to other systems where both RNA and DNA need to be detected. PMID:24961515

Appropriate 'housekeeping' genes for use in expression profiling the effects of environmental estrogens in fish

PubMed Central

Filby, Amy L; Tyler, Charles R

2007-01-01

Background Attempts to develop a mechanistic understanding of the effects of environmental estrogens on fish are increasingly conducted at the level of gene expression. Appropriate application of real-time PCR in such studies requires the use of a stably expressed 'housekeeping' gene as an internal control to normalize for differences in the amount of starting template between samples. Results We sought to identify appropriate genes for use as internal controls in experimental treatments with estrogen by analyzing the expression of eight functionally distinct 'housekeeping' genes (18S ribosomal RNA [18S rRNA], ribosomal protein l8 [rpl8], elongation factor 1 alpha [ef1a], glucose-6-phosphate dehydrogenase [g6pd], beta actin [bactin], glyceraldehyde-3-phosphate dehydrogenase [gapdh], hypoxanthine phosphoribosyltransferase 1 [hprt1], and tata box binding protein [tbp]) following exposure to the environmental estrogen, 17α-ethinylestradiol (EE2), in the fathead minnow (Pimephales promelas). Exposure to 10 ng/L EE2 for 21 days down-regulated the expression of ef1a, g6pd, bactin and gapdh in the liver, and bactin and gapdh in the gonad. Some of these effects were gender-specific, with bactin in the liver and gapdh in the gonad down-regulated by EE2 in males only. Furthermore, when ef1a, g6pd, bactin or gapdh were used for normalization, the hepatic expression of two genes of interest, vitellogenin (vtg) and cytochrome P450 1A (cyp1a) following exposure to EE2 was overestimated. Conclusion Based on the data presented, we recommend 18S rRNA, rpl8, hprt1 and/or tbp, but not ef1a, g6pd, bactin and/or gapdh, as likely appropriate internal controls in real-time PCR studies of estrogens effects in fish. Our studies show that pre-validation of control genes considering the scope and nature of the experiments to be performed, including both gender and tissue type, is critical for accurate assessments of the effects of environmental estrogens on gene expression in fish. PMID:17288598

Evolution of Fish Let-7 MicroRNAs and Their Expression Correlated to Growth Development in Blunt Snout Bream

PubMed Central

Zhao, Bo-Wen; Zhou, Lai-Fang; Liu, Yu-Long; Wan, Shi-Ming; Gao, Ze-Xia

2017-01-01

The lethal-7 (let-7) miRNA, known as one of the first founding miRNAs, is present in multiple copies in a genome and has diverse functions in animals. In this study, comparative genomic analysis of let-7 miRNAs members in fish species indicated that let-7 miRNA is a sequence conserved family in fish, while different species have the variable gene copy numbers. Among the ten members including let-7a/b/c/d/e/f/g/h/i/j, the let-7a precursor sequence was more similar to ancestral sequences, whereas other let-7 miRNA members were separate from the late differentiation of let-7a. The mostly predicted target genes of let-7 miRNAs are involved in biological process, especially developmental process and growth through Gene Ontology (GO) enrichment analysis. In order to identify the possible different functions of these ten miRNAs in fish growth development, their expression levels were quantified in adult males and females of Megalobrama amblycephala, as well as in 3-, 6-, and 12-months-old individuals with relatively slow- and fast-growth rates. These ten miRNAs had similar tissue expression patterns between males and females, with higher expression levels in the brain and pituitary than that in other tissues (p < 0.05). Among these miRNAs, the relative expression level of let-7a was the highest among almost all the tested tissues, followed by let-7b, let-7d and let-7c/e/f/g/h/i/j. As to the groups with different growth rates, the expression levels of let-7 miRNAs in pituitary and brain from the slow-growth group were always significantly higher than that in the fast-growth group (p < 0.05). These results suggest that let-7 miRNA members could play an important role in the regulation of growth development in M. amblycephala through negatively regulating expression of their target genes. PMID:28300776

Evidence for leptin expression in fishes.

PubMed

Johnson, R M; Johnson, T M; Londraville, R L

2000-06-01

Tissues from bony fish were screened with anti-mouse leptin antibodies to detect the presence of the fat-regulating hormone in fishes. Low molecular-weight (16 kDa) immunoreactive bands were detected in blood, brain, heart and liver of green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), largemouth bass (Micropterus salmoides), white crappie (Pomonix annularis), channel catfish (Ictalurus punctatus), and rainbow trout (Oncorhynchus mykiss). To further verify that we had identified leptin, the response of fish "leptin" was measured in fed and fasted green sunfish. Fed sunfish had approximately threefold higher concentration of leptin in blood than did fasted sunfish (fed vs. fasted; 0.599 +/- 0.03 microg/microl vs. 0.196 +/- 0.04 microg/microl; P > F = 0.0001), which is consistent with mammalian models of leptin function. Brain leptin concentration is also positively correlated with percent body fat in white crappie and bluegill. Based upon electrophoretic mobility, immunoreactivity, response to fasting, and correlation with adiposity, we believe we have the first evidence for leptin expression in an ectotherm.

Expression Profiles of Branchial FXYD Proteins in the Brackish Medaka Oryzias dancena: A Potential Saltwater Fish Model for Studies of Osmoregulation

PubMed Central

Yang, Wen-Kai; Kang, Chao-Kai; Chang, Chia-Hao; Hsu, An-Di; Lee, Tsung-Han; Hwang, Pung-Pung

2013-01-01

FXYD proteins are novel regulators of Na+-K+-ATPase (NKA). In fish subjected to salinity challenges, NKA activity in osmoregulatory organs (e.g., gills) is a primary driving force for the many ion transport systems that act in concert to maintain a stable internal environment. Although teleostean FXYD proteins have been identified and investigated, previous studies focused on only a limited group of species. The purposes of the present study were to establish the brackish medaka (Oryzias dancena) as a potential saltwater fish model for osmoregulatory studies and to investigate the diversity of teleostean FXYD expression profiles by comparing two closely related euryhaline model teleosts, brackish medaka and Japanese medaka (O. latipes), upon exposure to salinity changes. Seven members of the FXYD protein family were identified in each medaka species, and the expression of most branchial fxyd genes was salinity-dependent. Among the cloned genes, fxyd11 was expressed specifically in the gills and at a significantly higher level than the other fxyd genes. In the brackish medaka, branchial fxyd11 expression was localized to the NKA-immunoreactive cells in gill epithelia. Furthermore, the FXYD11 protein interacted with the NKA α-subunit and was expressed at a higher level in freshwater-acclimated individuals relative to fish in other salinity groups. The protein sequences and tissue distributions of the FXYD proteins were very similar between the two medaka species, but different expression profiles were observed upon salinity challenge for most branchial fxyd genes. Salinity changes produced different effects on the FXYD11 and NKA α-subunit expression patterns in the gills of the brackish medaka. To our knowledge, this report is the first to focus on FXYD expression in the gills of closely related euryhaline teleosts. Given the advantages conferred by the well-developed Japanese medaka system, we propose the brackish medaka as a saltwater fish model for osmoregulatory studies. PMID:23383199

Evaluation of Whether Gemfibrozil is a Peroxisome Proliferator in Fish

EPA Science Inventory

Gemfibrozil is a pharmaceutical that indirectly modulates cholesterol biosynthesis through effects on peroxisome proliferator-activated receptors (PPAR), which are transcriptional cofactors that regulate expression of genes related to lipid metabolism. An enzyme found in the pero...

Gene expression changes in female zebrafish (Danio rerio) brain in response to acute exposure to methylmercury

USGS Publications Warehouse

Richter, Catherine A.; Garcia-Reyero, Natàlia; Martyniuk, Chris; Knoebl, Iris; Pope, Marie; Wright-Osment, Maureen K.; Denslow, Nancy D.; Tillitt, Donald E.

2011-01-01

Methylmercury (MeHg) is a potent neurotoxicant and endocrine disruptor that accumulates in aquatic systems. Previous studies have shown suppression of hormone levels in both male and female fish, suggesting effects on gonadotropin regulation in the brain. The gene expression profile in adult female zebrafish whole brain induced by acute (96 h) MeHg exposure was investigated. Fish were exposed by injection to 0 or 0.5(mu or u)g MeHg/g. Gene expression changes in the brain were examined using a 22,000-feature zebrafish microarray. At a significance level of p

Interactive effect of high environmental ammonia and nutritional status on ecophysiological performance of European sea bass (Dicentrarchus labrax) acclimated to reduced seawater salinities.

PubMed

Sinha, Amit Kumar; Rasoloniriana, Rindra; Dasan, Antony Franklin; Pipralia, Nitin; Blust, Ronny; De Boeck, Gudrun

2015-03-01

We investigated the interactive effect of ammonia toxicity, salinity challenge and nutritional status on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to normal seawater (32ppt), to brackish water (20ppt and 10ppt) and to hyposaline water (2.5ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20mg/L ∼1.18mM representing 50% of 96h LC50 value for ammonia) for 12h, 48h, 84h and 180h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Biochemical responses such as ammonia (Jamm) and urea excretion rate, plasma ammonia, urea and lactate, plasma ions (Na(+), Cl(-) and K(+)) and osmolality, muscle water content (MWC) and liver and muscle energy budget (glycogen, lipid and protein), as well as branchial Na(+)/K(+)-ATPase (NKA) and H(+)-ATPase activity, and branchial mRNA expression of NKA and Na(+)/K(+)/2Cl(-) co-transporter (NKCC1) were investigated in order to understand metabolic and ion- osmoregulatory consequences of the experimental conditions. During HEA, Jamm was inhibited in fasted fish at 10ppt, while fed fish were still able to excrete efficiently. At 2.5ppt, both feeding groups subjected to HEA experienced severe reductions and eventually a reversion in Jamm. Overall, the build-up of plasma ammonia in HEA exposed fed fish was much lower than fasted ones. Unlike fasted fish, fed fish acclimated to lower salinities (10ppt-2.5ppt) could maintain plasma osmolality, [Na(+)], [Cl(-)] and MWC during HEA exposure. Thus fed fish were able to sustain ion-osmotic homeostasis which was associated with a more pronounced up-regulation in NKA expression and activity. At 2.5ppt both feeding groups activated H(+)-ATPase. The expression of NKCC1 was down-regulated at lower salinities in both fed and fasted fish, but was upregulated within each salinity after a few days of HEA exposure. Though an increment in plasma lactate content and a decline in energy stores were noted for both feeding regimes, the effect was more severe in feed deprived fish. Overall, several different physiological processes were disturbed in fasted sea bass during HEA exposure while feeding alleviated adverse effects of high ammonia and salinity challenge. This suggests that low food availability can render fish more vulnerable to external ammonia, especially at reduced seawater salinities. Copyright © 2015 Elsevier B.V. All rights reserved.

Kisspeptin regulates the hypothalamus-pituitary-gonad axis gene expression during sexual maturation in the cinnamon clownfish, Amphiprion melanopus.

PubMed

Kim, Na Na; Shin, Hyun Suk; Choi, Young Jae; Choi, Cheol Young

2014-02-01

Kisspeptins (Kiss) have been recognized as potent regulators of reproduction in teleosts, and Kiss is suggested to be a key regulator of the hypothalamus-pituitary-gonad axis (HPG). However, its regulatory role on reproduction in fish remains unclear. Therefore, to investigate the role of Kiss on fish reproduction, this study aimed to test differences in the hormones of the HPG axis, Kiss as neuropeptides, and sex steroids on the sexual maturation of paired cinnamon clownfish, Amphiprion melanopus, following treatment with Kiss. We investigated the actions of sex maturation hormones, including HPG axis hormones and sex steroid hormones, such as gonadotropin-releasing hormones, gonadotropin hormones (GTHs), GTH receptors, estrogen receptors, and vitellogenin in the pituitary, gonads, and liver following treatment with Kiss. The expression levels of HPG axis genes increased after the Kiss injection. In addition, the levels of plasma 17α-hydroxypregnenolone, estradiol-17β, and 11-ketotestosterone increased. These results support the hypothesis that Kiss play important roles in the regulation of the HPG axis and are most likely involved in gonadal development and sexual maturation in cinnamon clownfish. Copyright © 2013 Elsevier Inc. All rights reserved.

Molecular processes of transgenerational acclimation to a warming ocean

NASA Astrophysics Data System (ADS)

Veilleux, Heather D.; Ryu, Taewoo; Donelson, Jennifer M.; van Herwerden, Lynne; Seridi, Loqmane; Ghosheh, Yanal; Berumen, Michael L.; Leggat, William; Ravasi, Timothy; Munday, Philip L.

2015-12-01

Some animals have the remarkable capacity to acclimate across generations to projected future climate change; however, the underlying molecular processes are unknown. We sequenced and assembled de novo transcriptomes of adult tropical reef fish exposed developmentally or transgenerationally to projected future ocean temperatures and correlated the resulting expression profiles with acclimated metabolic traits from the same fish. We identified 69 contigs representing 53 key genes involved in thermal acclimation of aerobic capacity. Metabolic genes were among the most upregulated transgenerationally, suggesting shifts in energy production for maintaining performance at elevated temperatures. Furthermore, immune- and stress-responsive genes were upregulated transgenerationally, indicating a new complement of genes allowing the second generation of fish to better cope with elevated temperatures. Other differentially expressed genes were involved with tissue development and transcriptional regulation. Overall, we found a similar suite of differentially expressed genes among developmental and transgenerational treatments. Heat-shock protein genes were surprisingly unresponsive, indicating that short-term heat-stress responses may not be a good indicator of long-term acclimation capacity. Our results are the first to reveal the molecular processes that may enable marine fishes to adjust to a future warmer environment over multiple generations.

Long-term dietary replacement of fishmeal and fish oil in diets for rainbow trout (Oncorhynchus mykiss): Effects on growth, whole body fatty acids and intestinal and hepatic gene expression

PubMed Central

Lazzarotto, Viviana; Larroquet, Laurence; Corraze, Geneviève

2018-01-01

The effects of replacing fishmeal and fish oil with a plant-based diet were studied in juvenile (10g) and ongrowing (250-350g) rainbow trout from first-feeding. Feed-related differences in the intestinal and hepatic transcriptome were examined in juveniles after 7 months of feeding at 7°C. Based on microarray results obtained for juveniles, the expression of selected genes related to lipid, cholesterol and energy metabolisms, was assessed by RT-qPCR in ongrowing trout after 6 additional months of feeding at 17°C. Plasma glucose and cholesterol, lipid content and fatty acid profile of whole body were analyzed at both stages. After 7 months at 7°C, all juveniles reached the same body weight (10g), while at 13 months ongrowing fish fed the totally plant-based diet exhibited lower body weight (234 vs 330-337g). Body lipid content was higher in juveniles fed the totally plant-based diet (13.2 vs 9.4–9.9%), and plasma cholesterol was about 2-times lower in trout fed the plant-based diets at both stages. Fatty acid profile mirrored that of the respective diet, with low proportions of long-chain n-3 polyunsaturated fatty acids in fish fed plant-based diets. Genes involved in protein catabolism, carbohydrate metabolism and trafficking were down-regulated in the intestines of juveniles fed the plant-based diets. This was not true for ongrowing fish. Genes involved in lipid and cholesterol metabolisms were up-regulated in the livers of fish fed plant-based diets for both stages. In this study, feeding trout a totally plant-based diet from first-feeding affect a relatively low proportion of metabolism-related genes. In the longer term, when fish were reared at a higher temperature, only some of these changes were maintained (i.e. up-regulation of lipid/cholesterol metabolism). Although the plant-based diets tested in this study had no major deficiencies, small adjustments in the feed-formula are needed to further optimize growth performance while sparing marine resources. PMID:29364933

Tributyltin impaired reproductive success in female zebrafish through disrupting oogenesis, reproductive behaviors and serotonin synthesis.

PubMed

Xiao, Wei-Yang; Li, Ying-Wen; Chen, Qi-Liang; Liu, Zhi-Hao

2018-07-01

Tributyltin (TBT), an organotin acting as aromatase (Cyp19a1) inhibitor, has been found to disrupt gametogenesis and reproductive behaviors in several fish species. However, few studies addressing the mechanisms underlying the impaired gametogenesis and reproduction have been reported. In this study, female adults of zebrafish (Danio rerio) were continuously exposed to two nominal concentrations of TBT (100 and 500 ng/L, actual concentrations: 90.8 ± 1.3 ng/L and 470.3 ± 2.7 ng/L, respectively) for 28 days. After exposures, TBT decreased the total egg number, reduced the hatchability and elevated the mortality of the larvae. Decreased gonadosomatic index (GSI) and altered percentages of follicles in different developmental stages (increased early-stage follicles and reduced mid/late-stage follicles) were also observed in the ovary of TBT-treated fish. TBT also lowered the plasma level of 17β-estradiol and suppressed the expressions of cyp19a1a in the ovary. In treated fish, up-regulated expressions of aldhla2, sycp3 and dmc1 were present in the ovary, indicating an enhanced level of meiosis. The mRNA level of vtg1 was dramatically suppressed in the liver of TBT-treated fish, suggesting an insufficient synthesis of Vtg protein, consistent with the decreased percentage of mid/late-stage follicles in the ovaries. Moreover, TBT significantly suppressed the reproductive behaviors of the female fish (duration of both sexes simultaneously in spawning area, the frequency of meeting and the visit in spawning area) and down-regulated the mRNA levels of genes involved in the regulation of reproductive behaviors (cyp19a1b, gnrh-3 and kiss 2) in the brain. In addition, TBT significantly suppressed the expressions of serotonin-related genes, such as tph2 (encoding serotonin synthase), pet1 (marker of serotonin neuron) and kiss 1 (the modulator of serotonin synthesis), suggesting that TBT might disrupt the non-reproductive behaviors of zebrafish. The present study demonstrated that TBT may impair the reproductive success of zebrafish females probably through disrupting oogenesis, disturbing reproductive behaviors and altering serotonin synthesis. The present study greatly extends our understanding on the reproductive toxicity of TBT on fish. Copyright © 2018 Elsevier B.V. All rights reserved.

Epigenetic modification and inheritance in sexual reversal of fish.

PubMed

Shao, Changwei; Li, Qiye; Chen, Songlin; Zhang, Pei; Lian, Jinmin; Hu, Qiaomu; Sun, Bing; Jin, Lijun; Liu, Shanshan; Wang, Zongji; Zhao, Hongmei; Jin, Zonghui; Liang, Zhuo; Li, Yangzhen; Zheng, Qiumei; Zhang, Yong; Wang, Jun; Zhang, Guojie

2014-04-01

Environmental sex determination (ESD) occurs in divergent, phylogenetically unrelated taxa, and in some species, co-occurs with genetic sex determination (GSD) mechanisms. Although epigenetic regulation in response to environmental effects has long been proposed to be associated with ESD, a systemic analysis on epigenetic regulation of ESD is still lacking. Using half-smooth tongue sole (Cynoglossus semilaevis) as a model-a marine fish that has both ZW chromosomal GSD and temperature-dependent ESD-we investigated the role of DNA methylation in transition from GSD to ESD. Comparative analysis of the gonadal DNA methylomes of pseudomale, female, and normal male fish revealed that genes in the sex determination pathways are the major targets of substantial methylation modification during sexual reversal. Methylation modification in pseudomales is globally inherited in their ZW offspring, which can naturally develop into pseudomales without temperature incubation. Transcriptome analysis revealed that dosage compensation occurs in a restricted, methylated cytosine enriched Z chromosomal region in pseudomale testes, achieving equal expression level in normal male testes. In contrast, female-specific W chromosomal genes are suppressed in pseudomales by methylation regulation. We conclude that epigenetic regulation plays multiple crucial roles in sexual reversal of tongue sole fish. We also offer the first clues on the mechanisms behind gene dosage balancing in an organism that undergoes sexual reversal. Finally, we suggest a causal link between the bias sex chromosome assortment in the offspring of a pseudomale family and the transgenerational epigenetic inheritance of sexual reversal in tongue sole fish.

The TORC1/P70S6K and TORC1/4EBP1 signaling pathways have a stronger contribution on skeletal muscle growth than MAPK/ERK in an early vertebrate: Differential involvement of the IGF system and atrogenes.

PubMed

Fuentes, Eduardo N; Einarsdottir, Ingibjörg Eir; Paredes, Rodolfo; Hidalgo, Christian; Valdes, Juan Antonio; Björnsson, Björn Thrandur; Molina, Alfredo

2015-01-01

Knowledge about the underlying mechanisms, particularly the signaling pathways that account for muscle growth in vivo in early vertebrates is still scarce. Fish (Paralichthys adspersus) were fasted for 3weeks to induce a catabolic period of strong muscle atrophy. Subsequently, fish were refed for 2weeks to induce compensatory muscle hypertrophy. During refeeding, the fish were treated daily with either rapamycin (TORC blocker), PD98059 (MEK blocker), or PBS (V; vehicle), or were untreated (C; control). Rapamycin and PD98059 differentially impaired muscle cellularity in vivo, growth performance, and the expression of growth-related genes, and the inhibition of TORC1 had a greater impact on fish muscle growth than the inhibition of MAPK. Blocking TORC1 inhibited the phosphorylation of P70S6K and 4EBP1, two downstream components activated by TORC1, thus affecting protein contents in muscle. Concomitantly, the gene expression in muscle of igf-1, 2 and igfbp-4, 5 was down-regulated while the expression of atrogin-1, murf-1, and igfbp-2, 3 was up-regulated. Muscle hypertrophy was abolished and muscle atrophy was promoted, which finally affected body weight. TORC2 complex was not affected by rapamycin. On the other hand, the PD98059 treatment triggered ERK inactivation, a downstream component activated by MEK. mRNA contents of igf-1 in muscle were down-regulated, and muscle hypertrophy was partially impaired. The present study provides the first direct data on the in vivo contribution of TORC1/P70S6K, TORC1/4EBP1, and MAPK/ERK signaling pathways in the skeletal muscle of an earlier vertebrate, and highlights the transcendental role of TORC1 in growth from the cellular to organism level. Copyright © 2014 Elsevier Inc. All rights reserved.

Identification of a gene set to evaluate the potential effects of loud sounds from seismic surveys on the ears of fishes: a study with Salmo salar

PubMed Central

Andrews, C D; Payne, J F; Rise, M L

2014-01-01

Functional genomic studies were carried out on the inner ear of Atlantic salmon Salmo salar following exposure to a seismic airgun. Microarray analyses revealed 79 unique transcripts (passing background threshold), with 42 reproducibly up-regulated and 37 reproducibly down-regulated in exposed v. control fish. Regarding the potential effects on cellular energetics and cellular respiration, altered transcripts included those with roles in oxygen transport, the glycolytic pathway, the Krebs cycle and the electron transport chain. Of these, a number of transcripts encoding haemoglobins that are important in oxygen transport were up-regulated and among the most highly expressed. Up-regulation of transcripts encoding nicotinamide riboside kinase 2, which is also important in energy production and linked to nerve cell damage, points to evidence of neuronal damage in the ear following noise exposure. Transcripts related to protein modification or degradation also indicated potential damaging effects of sound on ear tissues. Notable in this regard were transcripts associated with the proteasome–ubiquitin pathway, which is involved in protein degradation, with the transcript encoding ubiquitin family domain-containing protein 1 displaying the highest response to exposure. The differential expression of transcripts observed for some immune responses could potentially be linked to the rupture of cell membranes. Meanwhile, the altered expression of transcripts for cytoskeletal proteins that contribute to the structural integrity of the inner ear could point to repair or regeneration of ear tissues including auditory hair cells. Regarding potential effects on hormones and vitamins, the protein carrier for thyroxine and retinol (vitamin A), namely transthyretin, was altered at the transcript expression level and it has been suggested from studies in mammalian systems that retinoic acid may play a role in the regeneration of damaged hair cells. The microarray experiment identified the transcript encoding growth hormone I as up-regulated by loud sound, supporting previous evidence linking growth hormone to hair cell regeneration in fishes. Quantitative (q) reverse transcription (RT) polymerase chain reaction (qRT-PCR) analyses confirmed dysregulation of some microarray-identified transcripts and in some cases revealed a high level of biological variability in the exposed group. These results support the potential utility of molecular biomarkers to evaluate the effect of seismic surveys on fishes with studies on the ears being placed in a priority category for development of exposure–response relationships. Knowledge of such relationships is necessary for addressing the question of potential size of injury zones. PMID:24814183

Expression kinetics of key genes in the early innate immune response to Great Lakes viral hemorrhagic septicemia virus IVb infection in yellow perch (Perca flavescens)

USGS Publications Warehouse

Olson, Wendy; Emmenegger, Eveline; Glenn, Jolene; Simchick, Crystal; Winton, Jim; Goetz, Frederick

2013-01-01

The recently discovered strain of viral hemorrhagic septicemia virus, VHSV-IVb, represents an example of the introduction of an extremely pathogenic rhabdovirus capable of infecting a wide variety of new fish species in a new host-environment. The goal of the present study was to delineate the expression kinetics of key genes in the innate immune response relative to the very early stages of VHSV-IVb infection using the yellow perch (Perca flavescens) as a model. Administration of VHSV-IVb by IP-injection into juvenile yellow perch resulted in 84% cumulative mortality, indicating their high susceptibility to this disease. In fish sampled in the very early stages of infection, a significant up-regulation of Mx gene expression in the liver, as well as IL-1β and SAA activation in the head kidney, spleen, and liver was directly correlated to viral load. The potential down-regulation of Mx in the hematopoietic tissues, head kidney and spleen, may represent a strategy utilized by the virus to increase replication.

Characterisation and expression analysis of B-cell activating factor (BAFF) in spiny dogfish (Squalus acanthias): cartilaginous fish BAFF has a unique extra exon that may impact receptor binding.

PubMed

Li, Ronggai; Dooley, Helen; Wang, Tiehui; Secombes, Christopher J; Bird, Steve

2012-04-01

B-cell activating factor (BAFF), also known as tumour necrosis factor (TNF) ligand superfamily member 13B, is an important immune regulator with critical roles in B-cell survival, proliferation, differentiation and immunoglobulin secretion. A BAFF gene has been cloned from spiny dogfish (Squalus acanthias) and its expression studied. The dogfish BAFF encodes for an anchored type-II transmembrane protein of 288 aa with a putative furin protease cleavage site and TNF family signature as seen in BAFFs from other species. The identity of dogfish BAFF has also been confirmed by conserved cysteine residues, and phylogenetic tree analysis. The dogfish BAFF gene has an extra exon not seen in teleost fish, birds and mammals that encodes for 29 aa and may impact on receptor binding. The dogfish BAFF is highly expressed in immune tissues, such as spleen, and is up-regulated by PWM in peripheral blood leucocytes, suggesting a potentially important role in the immune system. Copyright © 2011 Elsevier Ltd. All rights reserved.

Diet affects the redox system in developing Atlantic cod (Gadus morhua) larvae.

PubMed

Penglase, Samuel; Edvardsen, Rolf B; Furmanek, Tomasz; Rønnestad, Ivar; Karlsen, Ørjan; van der Meeren, Terje; Hamre, Kristin

2015-08-01

The growth and development of marine fish larvae fed copepods is superior to those fed rotifers, but the underlying molecular reasons for this are unclear. In the following study we compared the effects of such diets on redox regulation pathways during development of Atlantic cod (Gadus morhua) larvae. Cod larvae were fed a control diet of copepods or the typical rotifer/Artemia diet commonly used in commercial marine fish hatcheries, from first feeding until after metamorphosis. The oxidised and reduced glutathione levels, the redox potential, and the mRNA expression of 100 genes in redox system pathways were then compared between treatments during larval development. We found that rotifer/Artemia-fed cod larvae had lower levels of oxidised glutathione, a more reduced redox potential, and altered expression of approximately half of the redox system genes when compared to copepod-fed larvae. This rotifer/Artemia diet-induced differential regulation of the redox system was greatest during periods of suboptimal growth. Upregulation of the oxidative stress response transcription factor, nrf2, and NRF2 target genes in rotifer/Artemia fed larvae suggest this diet induced an NRF2-mediated oxidative stress response. Overall, the data demonstrate that nutritional intake plays a role in regulating the redox system in developing fish larvae. This may be a factor in dietary-induced differences observed in larval growth. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Kcnh1 Voltage-gated Potassium Channels Are Essential for Early Zebrafish Development*

PubMed Central

Stengel, Rayk; Rivera-Milla, Eric; Sahoo, Nirakar; Ebert, Christina; Bollig, Frank; Heinemann, Stefan H.; Schönherr, Roland; Englert, Christoph

2012-01-01

The Kcnh1 gene encodes a voltage-gated potassium channel highly expressed in neurons and involved in tumor cell proliferation, yet its physiological roles remain unclear. We have used the zebrafish as a model to analyze Kcnh1 function in vitro and in vivo. We found that the kcnh1 gene is duplicated in teleost fish (i.e. kcnh1a and kcnh1b) and that both genes are maternally expressed during early development. In adult zebrafish, kcnh1a and kcnh1b have distinct expression patterns but share expression in brain and testis. Heterologous expression of both genes in Xenopus oocytes revealed a strong conservation of characteristic functional properties between human and fish channels, including a unique sensitivity to intracellular Ca2+/calmodulin and modulation of voltage-dependent gating by extracellular Mg2+. Using a morpholino antisense approach, we demonstrate a strong kcnh1 loss-of-function phenotype in developing zebrafish, characterized by growth retardation, delayed hindbrain formation, and embryonic lethality. This late phenotype was preceded by transcriptional up-regulation of known cell-cycle inhibitors (p21, p27, cdh2) and down-regulation of pro-proliferative factors, including cyclin D1, at 70% epiboly. These results reveal an unanticipated basic activity of kcnh1 that is crucial for early embryonic development and patterning. PMID:22927438

Histological and transcriptomic responses of two immune organs, the spleen and head kidney, in Nile tilapia (Oreochromis niloticus) to long-term hypersaline stress.

PubMed

Xu, Chang; Li, Erchao; Suo, Yantong; Su, Yujie; Lu, Minghui; Zhao, Qun; Qin, Jian G; Chen, Liqiao

2018-05-01

Hyperosmotic stress can adversely affect fish immunity, but little is known about the histological and transcriptomic responses of immune organs in fish in a hyperosmotic environment. This study evaluated the effects of long-term hypersaline conditions (16‰) on the growth, histology and transcriptomics of the two main immune organs, the spleen and head kidney, in Nile tilapia Oreochromis niloticus relative to those reared in freshwater for eight weeks. No differences in weight gain and specific growth rate were found between fish reared under these two salinities. Hyperosmotic stress induced a congestive or enlarged spleen. Platelet- and coagulation-related gene expression was significantly decreased in tilapia at 16‰. The red cell distribution width and value of the mean corpuscular hemoglobin were significantly greater in fish at 16‰ salinity than in control fish in freshwater. A large volume of melano-macrophages in the spleen and pigment deposition in both the spleen and head kidney were observed in the histological sections in fish at 16‰ salinity. Transmission electron microscopic results showed abnormal macrophages with deposition granules in the spleen and head kidney and more neutrophils in the head kidney of fish at 16‰ than in control fish. In total, 772 and 502 genes were annotated for significantly different expression in the spleen and head kidney, respectively, and corresponded to five and one significantly changed immune system pathways, respectively. The complement pathway in the spleen was significantly down-regulated at 16‰. This study indicates that long-term exposure of Nile tilapia to a hyperosmotic environment can induce splenomegaly, reduce coagulation function, enhance phagocytic activity and down-regulate the complement pathway in the spleen. The spleen is a more sensitive organ for immune responses to chronic ambient salinity stress than the head kidney in Nile tilapia. Copyright © 2018 Elsevier Ltd. All rights reserved.

Leptin stimulates hepatic growth hormone receptor and insulin-like growth factor gene expression in a teleost fish, the hybrid striped bass.

PubMed

Won, Eugene T; Douros, Jonathan D; Hurt, David A; Borski, Russell J

2016-04-01

Leptin is an anorexigenic peptide hormone that circulates as an indicator of adiposity in mammals, and functions to maintain energy homeostasis by balancing feeding and energy expenditure. In fish, leptin tends to be predominantly expressed in the liver, another important energy storing tissue, rather than in fat depots as it is in mammals. The liver also produces the majority of circulating insulin-like growth factors (IGFs), which comprise the mitogenic component of the growth hormone (GH)-IGF endocrine growth axis. Based on similar regulatory patterns of leptin and IGFs that we have documented in previous studies on hybrid striped bass (HSB: Morone saxatilis×Morone chrysops), and considering the co-localization of these peptides in the liver, we hypothesized that leptin might regulate the endocrine growth axis in a manner that helps coordinate somatic growth with energy availability. Using a HSB hepatocyte culture system to simulate autocrine or paracrine exposure that might occur within the liver, this study examines the potential for leptin to modulate metabolism and growth through regulation of IGF gene expression directly, or indirectly through the regulation of GH receptors (GHR), which mediate GH-induced IGF expression. First, we verified that GH (50nM) has a classical stimulatory effect on IGF-1 and additionally show it stimulates IGF-2 transcription in hepatocytes. Leptin (5 and/or 50nM) directly stimulated in vitro GHR2 gene expression within 8h of exposure, and both GHR1 and GHR2 as well as IGF-1 and IGF-2 gene expression after 24h. Cells were then co-incubated with submaximal concentrations of leptin and GH (25nM each) to test if they had a synergistic effect on IGF gene expression, possibly through increased GH sensitivity following GHR upregulation by leptin. In combination, however, the treatments only had an additive effect on stimulating IGF-1 mRNA despite their capacity to increase GHR mRNA abundance. This suggests that leptin's stimulatory effect on GHRs may be limited to enhancing transcription or mRNA stability rather than inducing full translation of functional receptors, at least within a 24-h time frame. Finally, leptin was injected IP (100ng/g and 1μg/gBW) to test the in vivo regulation of hepatic IGF-1 and GHR1 gene expression. The 100ng/g BW leptin dose significantly upregulated in vivo IGF-1 mRNA levels relative to controls after 24h of fasting, but neither dosage was effective at regulating GHR1 gene expression. These studies suggest that stimulation of growth axis component transcripts by leptin may be an important mechanism for coordinating somatic growth with nutritional state in these and perhaps other fish or vertebrates, and represent the first evidence of leptin regulating GHRs in vertebrates. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of dietary oxidized konjac glucomannan sulfates (OKGMS) and acidolysis-oxidized konjac glucomannan (A-OKGM) on the immunity and expression of immune-related genes of Schizothorax prenanti.

PubMed

Chen, Mingrui; Wang, Hongjie; Yan, Qiuping; Zheng, Qiaoran; Yang, Min; Lv, Zhenzhen; He, Mei; Feng, Limei; Zhao, Jiaqi; Tang, Tingting; Wu, Yinglong

2016-09-01

In the present study, konjac glucomannan (KGM) was degraded by H2O2, and then used trisulfonated sodium amine and HCl, individually, to obtain two kinds of derivatives: oxidized konjac glucomannan sulfates (OKGMS) and acidolysis-oxidized konjac glucomannan (A-OKGM). The effects of two OKGM modified products on the immune parameters and expressions of toll-like receptor 22 (TLR22), myeloid differentiation factor 88 (MyD88) and interferon regulatory factors 7 (IRF7) genes in Schizothorax prenanti were determined. The alternative haemolytic complement (ACH50) activity was found to be significantly increased by the OKGMS diets. The immunoglobulin M (IgM) level was significantly enhanced by the OKGMS diets. The lysozyme activity was significantly increased by both OKGMS and A-OKGM diets. The superoxide dismutase (T-SOD) activity in fish fed with all doses of OKGMS diets was significantly higher than that in fish fed with basal diet. The glutathione peroxidase (GSH-PX) activity in fish fed with 0.8% and 1.6% A-OKGM diets was significantly higher than control group. The malondialdehyde (MDA) level was significantly decreased by both OKGMS and A-OKGM diets. The 0.8% A-OKGM diet significantly up-regulated TLR22 gene expression in the head kidney and spleen. TLR22 gene expression was significantly promoted by all OKGMS diets in the mesonephros and liver. The MyD88 mRNA level in 1.6% A-OKGM group significantly increased in the head kidney. The low dose of OKGMS significantly induced the MyD88 gene expression in the mesonephros, gut and liver, while 0.8% A-OKGM group also showed a significantly enhanced MyD88 mRNA expression in the gut. High dose of OKGMS significantly increased the IRF7 mRNA expression in the mesonephros and spleen. Fish fed with low dose of A-OKGM showed significantly higher expression of IRF7 in the gut and liver. Present study suggested that OKGMS and A-OKGM can act as immunostimulant to improve the immune indexes and up-regulate the immune-related gene expressions. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effects of exogenous cortisol on myostatin transcription in rainbow trout, Oncorhynchus mykiss.

PubMed

Galt, Nicholas J; Froehlich, Jacob Michael; Remily, Ethan A; Romero, Sinibaldo R; Biga, Peggy R

2014-09-01

Glucocorticoids (GCs) strongly regulate myostatin expression in mammals via glucocorticoid response elements (GREs), and bioinformatics methods suggest that this regulatory mechanism is conserved among many vertebrates. However, the multiple myostatin genes found in some fishes may be an exception. In silico promoter analyses of the three putative rainbow trout (Oncorhynchus mykiss) myostatin promoters have failed to identify putative GREs, suggesting a divergence in myostatin function. Therefore, we hypothesized that myostatin mRNA expression is not regulated by glucocorticoids in rainbow trout. In this study, both juvenile rainbow trout and primary trout myoblasts were treated with cortisol to examine the effects on myostatin mRNA expression. Results suggest that exogenous cortisol does not regulate myostatin-1a and -1b expression in vivo, as myostatin mRNA levels were not significantly affected by cortisol treatment in either red or white muscle tissue. In red muscle, myostatin-2a levels were significantly elevated in the cortisol treatment group relative to the control, but not the vehicle control, at both 12 h and 24 h post-injection. As such, it is unclear if cortisol was acting alone or in combination with the vehicle. Cortisol increased myostatin-1b expression in a dose-dependent manner in vitro. Further work is needed to determine if this response is the direct result of cortisol acting on the myostatin-1b promoter or through an alternative mechanism. These results suggest that regulation of myostatin by cortisol may not be as highly conserved as previously thought and support previous work that describes potential functional divergence of the multiple myostatin genes in fishes. Copyright © 2014 Elsevier Inc. All rights reserved.

From molecule to behavior: Brain aromatase (cyp19a1b) characterization, expression analysis and its relation with social status and male agonistic behavior in a Neotropical cichlid fish.

PubMed

Ramallo, Martín R; Morandini, Leonel; Birba, Agustina; Somoza, Gustavo M; Pandolfi, Matías

2017-03-01

The enzyme aromatase, responsible for the conversion of C19 androgens to C18 estrogens, exists as two paralogue copies in teleost fish: Cyp19a1a mostly expressed in the gonads, referred as gonadal aromatase, and Cyp19a1b, mostly expressed in the brain, accordingly known as brain aromatase. The neural localization of Cyp19a1b is greatly contained within the social behavior network and mesolimbic reward system in fish, suggesting a strong role of estrogen synthesis in the regulation of social behavior. In this work we aimed to analyze the variation in cyp19a1b expression in brain and pituitary of males of a highly social cichlid, Cichlasoma dimerus (locally known as chanchita), and its relation with inter-individual variability in agonistic behavior in a communal social environment. We first characterized chanchita's cyp19a1b mRNA and deduced amino acid sequence, which showed a high degree of conservation when compared to other teleost brain aromatase sequences, and its tissue expression patterns. Within the brain, Cyp19a1b was solely detected at putative radial glial cells of the forebrain, close to the brain ventricles. We then studied the relative expression levels of cyp19a1b by Real Time PCR in the brain and pituitary of males of different social status, territorial vs. non-territorial, and its relationship with an index of agonistic behavior. We found that even though, brain aromatase expression did not differ between types of males, pituitary cyp19a1b expression levels positively correlated with the index of agonistic behavior. This suggests a novel role of the pituitary in the regulation of social behavior by local estrogen synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of two bacterial artificial chromosome shuttle vectors for a recombination-based cloning and regulated expression of large genes in mammalian cells.

PubMed

Hong, Y K; Kim, D H; Beletskii, A; Lee, C; Memili, E; Strauss, W M

2001-04-01

Most conditional expression vectors designed for mammalian cells have been valuable systems for studying genes of interest by regulating their expressions. The available vectors, however, are reliable for the short-length cDNA clones and not optimal for relatively long fragments of genomic DNA or long cDNAs. Here, we report the construction of two bacterial artificial chromosome (BAC) vectors, capable of harboring large inserts and shuttling among Escherichia coli, yeast, and mammalian cells. These two vectors, pEYMT and pEYMI, contain conditional expression systems which are designed to be regulated by tetracycline and mouse interferons, respectively. To test the properties of the vectors, we cloned in both vectors the green fluorescence protein (GFP) through an in vitro ligation reaction and the 17.8-kb-long X-inactive-specific transcript (Xist) cDNA through homologous recombination in yeast. Subsequently, we characterized their regulated expression properties using real-time quantitative RT-PCR (TaqMan) and RNA-fluorescent in situ hybridization (FISH). We demonstrate that these two BAC vectors are good systems for recombination-based cloning and regulated expression of large genes in mammalian cells. Copyright 2001 Academic Press.

Porcine peroxisome proliferator-activated receptor delta mediates the lipolytic effects of dietary fish oil to reduce body fat deposition.

PubMed

Yu, Y H; Wang, P H; Cheng, W T K; Mersmann, H J; Wu, S C; Ding, S T

2010-06-01

Peroxisome proliferator-activated receptor delta promotes fatty acid catabolism and energy expenditure in skeletal muscle and adipose tissues. A ligand for PPARdelta is required to activate PPARdelta function. Polyunsaturated fatty acids are potential ligands for PPARdelta activation. The current experiment was designed to determine the potential for PUFA, particularly from dietary fish oil, to activate porcine PPARdelta in vivo. Transgenic mice were generated to overexpress porcine PPARdelta in the adipose tissue. Mice were fed a high-saturated fat (13% beef tallow), or high-unsaturated fat (13% fish oil) diet, or a diet containing 4 mg/kg of a PPARdelta ligand (L165041) for 4 mo. Compared with beef tallow feeding, fish oil feeding reduced fat mass and decreased (P < 0.05) plasma triacylglycerol and FFA concentrations in the transgenic mice. Adipose tissue expression of genes involved in adipogenesis (i.e., lipoprotein lipase and adipocyte fatty acid-binding protein) was decreased in transgenic mice fed fish oil or the PPARdelta ligand. In the same mice, expression of the lipolytic gene, hormone-sensitive lipase was increased (P < 0.05). Fish oil feeding also stimulated expression of genes participating in fatty acid oxidation in the liver of transgenic mice compared with wild-type mice. Overall, these results indicate that PUFA may serve as natural and effective regulators of lipid catabolism in vivo and many of these effects may be generated from activation of PPARdelta.

Identification of new participants in the rainbow trout (Oncorhynchus mykiss) oocyte maturation and ovulation processes using cDNA microarrays

PubMed Central

Bobe, Julien; Montfort, Jerôme; Nguyen, Thaovi; Fostier, Alexis

2006-01-01

Background The hormonal control of oocyte maturation and ovulation as well as the molecular mechanisms of nuclear maturation have been thoroughly studied in fish. In contrast, the other molecular events occurring in the ovary during post-vitellogenesis have received far less attention. Methods Nylon microarrays displaying 9152 rainbow trout cDNAs were hybridized using RNA samples originating from ovarian tissue collected during late vitellogenesis, post-vitellogenesis and oocyte maturation. Differentially expressed genes were identified using a statistical analysis. A supervised clustering analysis was performed using only differentially expressed genes in order to identify gene clusters exhibiting similar expression profiles. In addition, specific genes were selected and their preovulatory ovarian expression was analyzed using real-time PCR. Results From the statistical analysis, 310 differentially expressed genes were identified. Among those genes, 90 were up-regulated at the time of oocyte maturation while 220 exhibited an opposite pattern. After clustering analysis, 90 clones belonging to 3 gene clusters exhibiting the most remarkable expression patterns were kept for further analysis. Using real-time PCR analysis, we observed a strong up-regulation of ion and water transport genes such as aquaporin 4 (aqp4) and pendrin (slc26). In addition, a dramatic up-regulation of vasotocin (avt) gene was observed. Furthermore, angiotensin-converting-enzyme 2 (ace2), coagulation factor V (cf5), adam 22, and the chemokine cxcl14 genes exhibited a sharp up-regulation at the time of oocyte maturation. Finally, ovarian aromatase (cyp19a1) exhibited a dramatic down-regulation over the post-vitellogenic period while a down-regulation of Cytidine monophosphate-N-acetylneuraminic acid hydroxylase (cmah) was observed at the time of oocyte maturation. Conclusion We showed the over or under expression of more that 300 genes, most of them being previously unstudied or unknown in the fish preovulatory ovary. Our data confirmed the down-regulation of estrogen synthesis genes during the preovulatory period. In addition, the strong up-regulation of aqp4 and slc26 genes prior to ovulation suggests their participation in the oocyte hydration process occurring at that time. Furthermore, among the most up-regulated clones, several genes such as cxcl14, ace2, adam22, cf5 have pro-inflammatory, vasodilatory, proteolytics and coagulatory functions. The identity and expression patterns of those genes support the theory comparing ovulation to an inflammatory-like reaction. PMID:16872517

Intestinal Fluid Permeability in Atlantic Salmon (Salmo salar L.) Is Affected by Dietary Protein Source.

PubMed

Hu, Haibin; Kortner, Trond M; Gajardo, Karina; Chikwati, Elvis; Tinsley, John; Krogdahl, Åshild

2016-01-01

In Atlantic salmon (Salmo salar L.), and also in other fish species, certain plant protein ingredients can increase fecal water content creating a diarrhea-like condition which may impair gut function and reduce fish growth. The present study aimed to strengthen understanding of the underlying mechanisms by observing effects of various alternative plant protein sources when replacing fish meal on expression of genes encoding proteins playing key roles in regulation of water transport across the mucosa of the distal intestine (DI). A 48-day feeding trial was conducted with five diets: A reference diet (FM) in which fish meal (72%) was the only protein source; Diet SBMWG with a mix of soybean meal (30%) and wheat gluten (22%); Diet SPCPM with a mix of soy protein concentrate (30%) and poultry meal (6%); Diet GMWG with guar meal (30%) and wheat gluten (14.5%); Diet PM with 58% poultry meal. Compared to fish fed the FM reference diet, fish fed the soybean meal containing diet (SBMWG) showed signs of enteritis in the DI, increased fecal water content of DI chyme and higher plasma osmolality. Altered DI expression of a battery of genes encoding aquaporins, ion transporters, tight junction and adherens junction proteins suggested reduced transcellular transport of water as well as a tightening of the junction barrier in fish fed the SBMWG diet, which may explain the observed higher fecal water content and plasma osmolality. DI structure was not altered for fish fed the other experimental diets but alterations in target gene expression and fecal water content were observed, indicating that alterations in water transport components may take place without clear effects on intestinal structure.

9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

Code of Federal Regulations, 2012 CFR

2012-01-01

...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be moved...

9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

Code of Federal Regulations, 2011 CFR

2011-01-01

...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be moved...

9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

Code of Federal Regulations, 2013 CFR

2013-01-01

...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be moved...

9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

Code of Federal Regulations, 2014 CFR

2014-01-01

...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be moved...

9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

Code of Federal Regulations, 2010 CFR

2010-01-01

...-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...-regulated fish species from VHS-regulated areas. (a) Except as provided in paragraphs (b) through (e) of this section, live VHS-regulated fish, including fish moved to live fish markets, may only be moved...

50 CFR 32.6 - What are the procedures for publication of refuge-specific sport fishing regulations?

Code of Federal Regulations, 2014 CFR

2014-10-01

... refuge-specific sport fishing regulations? 32.6 Section 32.6 Wildlife and Fisheries UNITED STATES FISH... sport fishing regulations? (a) Refuge-specific fishing regulations are issued only at the time of or after the opening of a wildlife refuge area to sport fishing. (b) Refuge-specific fishing regulations...

50 CFR 32.6 - What are the procedures for publication of refuge-specific sport fishing regulations?

Code of Federal Regulations, 2013 CFR

2013-10-01

... refuge-specific sport fishing regulations? 32.6 Section 32.6 Wildlife and Fisheries UNITED STATES FISH... sport fishing regulations? (a) Refuge-specific fishing regulations are issued only at the time of or after the opening of a wildlife refuge area to sport fishing. (b) Refuge-specific fishing regulations...

50 CFR 32.6 - What are the procedures for publication of refuge-specific sport fishing regulations?

Code of Federal Regulations, 2012 CFR

2012-10-01

... refuge-specific sport fishing regulations? 32.6 Section 32.6 Wildlife and Fisheries UNITED STATES FISH... sport fishing regulations? (a) Refuge-specific fishing regulations are issued only at the time of or after the opening of a wildlife refuge area to sport fishing. (b) Refuge-specific fishing regulations...

50 CFR 32.6 - What are the procedures for publication of refuge-specific sport fishing regulations?

Code of Federal Regulations, 2010 CFR

2010-10-01

... refuge-specific sport fishing regulations? 32.6 Section 32.6 Wildlife and Fisheries UNITED STATES FISH... sport fishing regulations? (a) Refuge-specific fishing regulations are issued only at the time of or after the opening of a wildlife refuge area to sport fishing. (b) Refuge-specific fishing regulations...

50 CFR 32.6 - What are the procedures for publication of refuge-specific sport fishing regulations?

Code of Federal Regulations, 2011 CFR

2011-10-01

... refuge-specific sport fishing regulations? 32.6 Section 32.6 Wildlife and Fisheries UNITED STATES FISH... sport fishing regulations? (a) Refuge-specific fishing regulations are issued only at the time of or after the opening of a wildlife refuge area to sport fishing. (b) Refuge-specific fishing regulations...

Pre-acclimation to low ammonia improves ammonia handling in common carp (Cyprinus carpio) when exposed subsequently to high environmental ammonia.

PubMed

Shrivastava, Jyotsna; Sinha, Amit Kumar; Datta, Surjya Narayan; Blust, Ronny; De Boeck, Gudrun

2016-11-01

We tested whether exposing fish to low ammonia concentrations induced acclimation processes and helped fish to tolerate subsequent (sub)lethal ammonia exposure by activating ammonia excretory pathways. Common carp (Cyprinus carpio) were pre-exposed to 0.27mM ammonia (∼10% 96h LC 50 ) for 3, 7 and 14days. Thereafter, each of these pre-exposed and parallel naïve groups were exposed to 1.35mM high environmental ammonia (HEA, ∼50% 96h LC 50 ) for 12h and 48h to assess the occurrence of ammonia acclimation based on sub-lethal end-points, and to lethal ammonia concentrations (2.7mM, 96h LC 50 ) in order to assess improved survival time. Results show that fish pre-exposed to ammonia for 3 and 7days had a longer survival time than the ammonia naïve fish. However, this effect disappeared after prolonged (14days) pre-exposure. Ammonia excretion rate (J amm ) was strongly inhibited (or even reversed) in the unacclimated groups during HEA. On the contrary, after 3days the pre-exposure fish maintained J amm while after 7days these pre-acclimated fish were able to increase J amm efficiently. Again, this effect disappeared after 14days of pre-acclimation. The efficient ammonia efflux in pre-acclimated fish was associated with the up-regulation of branchial mRNA expression of ammonia transporters and exchangers. Pre-exposure with ammonia for 3-7days stimulated an increment in the transcript level of gill Rhcg-a and Rhcg-b mRNA relative to the naïve control group and the up-regulation of these two Rhcg homologs was reinforced during subsequent HEA exposure. No effect of pre-exposure was noted for Rhbg. Relative to unacclimated fish, the transcript level of Na + /H + exchangers (NHE-3) was raised in 3-7days pre-acclimated fish and remained higher during the subsequent HEA exposure while gill H + -ATPase activities and mRNA levels were not affected by pre-acclimation episodes. Likewise, ammonia pre-acclimated fish with or without HEA exposure displayed pronounced up-regulation in Na + /K + -ATPase activity and mRNA expression relative to the corresponding ammonia naïve groups. Overall, these data suggest that ammonia acclimation was evident for both lethal and the sub-lethal endpoints through priming mechanisms in ammonia excretory transcriptional processes, but these acclimation effects were transient and disappeared after prolonged pre-exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of long real space flight on the whole genome mRNA expression properties in medaka Oryzias latipes

NASA Astrophysics Data System (ADS)

Kozlova, Olga; Gusev, Oleg; Levinskikh, Margarita; Sychev, Vladimir; Poddubko, Svetlana

The current study is addressed to the complex analysis of whole genome mRNA expression profile and properties of splicing variants formation in different organs of medaka fish exposed to prolonged space flight in the frame of joint Russia-Japan research program “Aquarium-AQH”. The fish were kept in the AQH joint-aquariums system in October-December 2013, followed by fixation in RNA-preserving buffers and freezing during the space flight. The samples we returned to the Earth frozen in March 2013 and mRNAs from four fish were sequenced in organ-specific manner using HiSeq Illumina sequencing platform. The ground group fish treated in the same way was used as a control. The comparison between the groups revealed space group-specific specific mRNA expression pattern. More than 50 genes (including several types of myosins) were down-regulated in the space group. Moreover, we found an evidence for formation of space group-specific splicing variants of mRNA. Taking together, the data suggest that in spite of aquatic environment, space flight-associated factors have a strong effect on the activity of fish genome. This work was supported in part by subsidy of the Russian Government to support the Program of competitive growth of Kazan Federal University among world class academic centres and universities.

The Effects of Endocrine Disruptors on Steroidogenesis Gene Expression Dynamics in Fathead Minnow

EPA Science Inventory

Steroid hormones play key roles in regulating reproduction and development and fish and other vertebrates. This presentation reports results from two in vitro experiments aimed characterizing the dynamics of transcriptional and metabolomic responses to endocrine disrupting chemi...

Involvement of the mitfa gene in the development of pigment cell in Japanese ornamental (Koi) carp (Cyprinus carpio L.).

PubMed

Liu, J H; Wen, S; Luo, C; Zhang, Y Q; Tao, M; Wang, D W; Deng, S M; Xiao, Y M

2015-03-31

A colored phenotype is an important feature of ornamental fish. In mammals, microphthalmia-associated transcription factor (MITF) was found to regulate the development of melanocytes. In this study, the mitfa cDNA was first cloned from the Japanese ornamental (Koi) carp (Cyprinus carpio L.), an important ornamental freshwater fish. The full-length cDNA of the mitfa gene contains 1634 bp, coding for 412 amino acids in Koi. The identity degree of mitfa amino acid sequences between the Koi carp and zebrafish is 92.9%. We tested the expression of the mitfa gene in several varieties of Koi using reverse transcription-polymerase chain reaction and found that the mitfa gene is highly expressed in the skin tissues of the Taisho sanke and the Procypris merus. Interestingly, the mitfa gene was also expressed in the Kohaku and Yamabaki ogon, although melanocytes were not observed in the skin. Koi carp embryos were transparent and colorless, while after hatching, different types of pigment cells successively emerged in a fixed order. In Taisho sanke, melanocytes first appeared in the trunk at approximately 12 days of age. Subsequently, there was a large area of melanocytes by 30 days of age. The expression level of the mitfa mRNA was low in early embryos and newly hatched larvae, and increased to high levels in 30-day-old fry. The results show that the mitfa gene is involved in regulating fish body color in the development of both melanocytes and pigment cells.

5S rRNA and accompanying proteins in gonads: powerful markers to identify sex and reproductive endocrine disruption in fish.

PubMed

Diaz de Cerio, Oihane; Rojo-Bartolomé, Iratxe; Bizarro, Cristina; Ortiz-Zarragoitia, Maren; Cancio, Ibon

2012-07-17

In anuran ovaries, 5S rDNA is regulated transcriptionally by transcription factor IIIA (TFIIIA), which upon transcription, binds 5S rRNA, forming 7S RNP. 5S rRNA can be stockpiled also in the form of 42S RNP bound to 42sp43. The aim of the present study was to assess the differential transcriptional regulation of 5S rRNA and associated proteins in thicklip gray mullet (Chelon labrosus) gonads. Up to 75% of the total RNA from mullet ovaries was 5S rRNA. qPCR quantification of 5S rRNA expression, in gonads of histologically sexed individuals from different geographical areas, successfully sexed animals. All males had expression levels that were orders of magnitude below expression levels in females, throughout an annual reproductive cycle, with the exception of two individuals: one in November and one in December. Moreover, intersex mullets from a polluted harbor had expression levels between both sexes. TFIIIA and 42sp43 were also very active transcriptionally in gonads of female and intersex mullets, in comparison to males. Nucleocytoplasmatic transport is important in this context and we also analyzed transcriptional levels of importins-α1, -α2, and -β2 and different exportins. Importin-αs behaved similarly to 5S rRNA. Thus, 5S rRNA and associated proteins constitute very powerful molecular markers of sex and effects of xenosterogens in fish gonads, with potential technological applications in the analysis of fish stock dynamics and reproduction as well as in environmental health assessment.

Low salinity affects cellularity, DNA methylation, and mRNA expression of igf1 in the liver of half smooth tongue sole (Cynoglossus semilaevis).

PubMed

Li, Siping; He, Feng; Wen, Haishen; Li, Jifang; Si, Yufeng; Liu, Mingyuan; Huang, Yajuan; Meng, Lingcai

2017-12-01

Animal growth depends on feedback regulation of hormone levels and environmental conditions. Insulin-like growth factor-1 (Igf1) promotes cell growth and differentiation and represses apoptosis and is highly regulated by the environment. Moreover, animals modify physiological homeostasis under stressful conditions through epigenetics and genetic regulatory mechanisms. Therefore, a comprehensive understanding of the effects of salt on fish growth is needed. In this study, half smooth tongue sole (Cynoglossus semilaevis) were subjected to 15‰ salinity for 0, 7, and 60 days (D) to assess the effects of low salinity on liver cellularity and growth. The results show that low salinity changed liver morphology, suggesting an increase in energy expenditure to recover from the osmotic disruption. igf1 was upregulated in female fish under 15‰ salinity after 7D and may participate in molecular repair. igf1 was downregulated after 60D of salt stress, resulting in retarded growth. Methylation levels were opposite to those of gene expression, suggesting inhibited regulation. Furthermore, three exons in the igf1 gene had significantly different methylation levels in fish under salt stress. Notably, more putative transcription factor binding sites were located in CpG sites at higher methylation levels. igf1 is not a sex-related gene, as no difference in methylation level was detected between males and females in the control group. These results clarify liver damage and changes in DNA methylation and mRNA expression of igf1, providing insight into the adverse effects of low salt on growth of C. semilaevis and the epigenetics and regulatory mechanisms involved in stressful conditions.

Effects of the UV filter benzophenone-3 (oxybenzone) at low concentrations in zebrafish (Danio rerio).

PubMed

Blüthgen, Nancy; Zucchi, Sara; Fent, Karl

2012-09-01

Organic UV filters including benzophenone-3 (BP-3) are widely used to protect humans and materials from damage by UV irradiation. Despite the environmental occurrence of BP-3 in the aquatic environment, little is known about its effects and modes of action. In the present study we assess molecular and physiological effects of BP-3 in adult male zebrafish (Danio rerio) and in eleuthero-embryos by a targeted gene expression approach focusing on the sex hormone system. Fish and embryos are exposed for 14 days and 120 hours post fertilization, respectively, to 2.4-312 μg/L and 8.2-438 μg/L BP-3. Chemical analysis of water and fish demonstrates that BP-3 is partly transformed to benzophenone-1 (BP-1) and both compounds are accumulated in adult fish. Biotransformation to BP-1 is absent in eleuthero-embryos. BP-3 exposure leads to similar alterations of gene expression in both adult fish and eleuthero-embryos. In the brain of adult males esr1, ar and cyp19b are down-regulated at 84 μg/L BP-3. There is no induction of vitellogenin expression by BP-3, both at the transcriptional and protein level. An overall down-regulation of the hsd3b, hsd17b3, hsd11b2 and cyp11b2 transcripts is observed in the testes, suggesting an antiandrogenic activity. No histological changes were observed in the testes after BP-3 treatment. The study leads to the conclusion that low concentrations of BP-3 exhibit similar multiple hormonal activities at the transcription level in two different life stages of zebrafish. Forthcoming studies should show whether this translates to additional physiological effects. Copyright © 2012 Elsevier Inc. All rights reserved.

Altered gene expression in the brain and ovaries of zebrafish (Danio rerio) exposed to the aromatase inhibitor fadrozole: microarray analysis and hypothesis generation.

PubMed

Villeneuve, L; Wang, Rong-Lin; Bencic, David C; Biales, Adam D; Martinović, Dalma; Lazorchak, James M; Toth, Gregory; Ankley, Gerald T

2009-08-01

As part of a research effort examining system-wide responses of the hypothalamic-pituitary-gonadal (HPG) axis in fish to endocrine-active chemicals (EACs) with different modes of action, zebrafish (Danio rerio) were exposed to 25 or 100 microg/L of the aromatase inhibitor fadrozole for 24, 48, or 96 h. Global transcriptional response in brain and ovarian tissue of fish exposed to 25 microg/L of fadrozole was compared to that in control fish using a commercially available, 22,000-gene oligonucleotide microarray. Transcripts altered in brain were functionally linked to differentiation, development, DNA replication, and cell cycle. Additionally, multiple genes associated with the one-carbon pool by folate pathway (KEGG 00670) were significantly up-regulated. Transcripts altered in ovary were functionally linked to cell-cell adhesion, extracellular matrix, vasculogenesis, and development. Promoter motif analysis identified GATA-binding factor 2, Ikaros 2, alcohol dehydrogenase gene regulator 1, myoblast-determining factor, and several heat shock factors as being associated with coexpressed gene clusters that were differentially expressed following exposure to fadrozole. Based on the transcriptional changes observed, it was hypothesized that fadrozole elicits neurodegenerative stress in brain tissue and that fish cope with this stress through proliferation of radial glial cells. Additionally, it was hypothesized that changes of gene expression in the ovary of fadrozole-exposed zebrafish reflect disruption of oocyte maturation and ovulation because of impaired vitellogenesis. These hypotheses and others derived from the microarray results provide a foundation for future studies aimed at understanding responses of the HPG axis to EACs and other chemical stressors.

Prolactin and growth hormone in fish osmoregulation

USGS Publications Warehouse

Sakamoto, T.; McCormick, S.D.

2006-01-01

Prolactin is an important regulator of multiple biological functions in vertebrates, and has been viewed as essential to ion uptake as well as reduction in ion and water permeability of osmoregulatory surfaces in freshwater and euryhaline fish. Prolactin-releasing peptide seems to stimulate prolactin expression in the pituitary and peripheral organs during freshwater adaptation. Growth hormone, a member of the same family of hormones as prolactin, promotes acclimation to seawater in several teleost fish, at least in part through the action of insulin-like growth factor I. In branchial epithelia, development and differentiation of the seawater-type chloride cell (and their underlying biochemistry) is regulated by GH, IGF-I, and cortisol, whereas the freshwater-type chloride cell is regulated by prolactin and cortisol. In the epithelia of gastrointestinal tract, prolactin induces cell proliferation during freshwater adaptation, whereas cortisol stimulates both cell proliferation and apoptosis. We propose that control of salinity acclimation in teleosts by prolactin and growth hormone primarily involves regulation of cell proliferation, apoptosis, and differentiation (the latter including upregulation of specific ion transporters), and that there is an important interaction of these hormones with corticosteroids. ?? 2005 Elsevier Inc. All rights reserved.

Molecular cloning and characterization of interferon regulatory factor 7 (IRF-7) in Japanese flounder, Paralichthys olivaceus.

PubMed

Hu, Guobin; Yin, Xiangyan; Xia, Jun; Dong, Xianzhi; Zhang, Jianyie; Liu, Qiuming

2010-12-01

Interferon regulatory factor (IRF) 7 in mammals is known to be a key player in regulating the type I interferon (IFN) response to viral infection as a transcription activator of IFNs and IFN-stimulated genes (ISGs). In this study, a full-length cDNA of Japanese flounder, Paralichthys olivaceus, (Po)IRF-7 was cloned and characterized. PoIRF-7 is 2032 bp in length, with an open reading frame (ORF) of 1293 bp that encodes 430 amino acid residues. The putative amino acid sequence shows the highest homology to fish IRF-7 with 51.5-76.3% identity and possesses a DNA-binding domain (DBD), an IRF association domain (IAD) and a serine-rich domain of vertebrate IRF-7. In addition, the tryptophan cluster of PoIRF-7 DBD consists of only four tryptophans, which is a characteristic unique to all fish IRF-7 members. The PoIRF-7 was expressed constitutively in all tested tissues of healthy flounders, with high levels in head kidney, spleen, gill, intestine and skin, and moderately expressed in FG9307 cells, a flounder gill epithelial cell line. Using a luciferase assay, PoIRF-7 was proved to be capable of activating fish type I IFN promoter in FG9307 cells. A quantitative real time PCR assay was employed to monitor the gene expression of PoIRF-7 and Mx in FG9307 cells and flounder head kidney and gill. Both genes were up-regulated by polyinosinic:polycytidylic acid (poly I:C) and lymphocystis disease virus (LCDV) though to a much lesser extent in FG9307 cells. Further, their transcription kinetics were similar in fish organs but different in FG9307 cells. These data provide insights into the functions of PoIRF-7 and imply a difference in PoIRF-7-related signaling pathways in antiviral response between cultured cells and live fish. Copyright © 2010 Elsevier Ltd. All rights reserved.

Developmental regulation of gonadotropin-releasing hormone gene expression by the MSX and DLX homeodomain protein families.

PubMed

Givens, Marjory L; Rave-Harel, Naama; Goonewardena, Vinodha D; Kurotani, Reiko; Berdy, Sara E; Swan, Christo H; Rubenstein, John L R; Robert, Benoit; Mellon, Pamela L

2005-05-13

Gonadotropin-releasing hormone (GnRH) is the central regulator of the hypothalamic-pituitary-gonadal axis, controlling sexual maturation and fertility in diverse species from fish to humans. GnRH gene expression is limited to a discrete population of neurons that migrate through the nasal region into the hypothalamus during embryonic development. The GnRH regulatory region contains four conserved homeodomain binding sites (ATTA) that are essential for basal promoter activity and cell-specific expression of the GnRH gene. MSX and DLX are members of the Antennapedia class of non-Hox homeodomain transcription factors that regulate gene expression and influence development of the craniofacial structures and anterior forebrain. Here, we report that expression patterns of the Msx and Dlx families of homeodomain transcription factors largely coincide with the migratory route of GnRH neurons and co-express with GnRH in neurons during embryonic development. In addition, MSX and DLX family members bind directly to the ATTA consensus sequences and regulate transcriptional activity of the GnRH promoter. Finally, mice lacking MSX1 or DLX1 and 2 show altered numbers of GnRH-expressing cells in regions where these factors likely function. These findings strongly support a role for MSX and DLX in contributing to spatiotemporal regulation of GnRH transcription during development.

Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment.

PubMed

Hablützel, Pascal I; Brown, Martha; Friberg, Ida M; Jackson, Joseph A

2016-09-01

The effect of anthropogenic environments on the function of the vertebrate immune system is a problem of general importance. For example, it relates to the increasing rates of immunologically-based disease in modern human populations and to the desirability of identifying optimal immune function in domesticated animals. Despite this importance, our present understanding is compromised by a deficit of experimental studies that make adequately matched comparisons between wild and captive vertebrates. We transferred post-larval fishes (three-spined sticklebacks), collected in the wild, to an anthropogenic (captive) environment. We then monitored, over 11 months, how the systemic expression of immunity genes changed in comparison to cohort-matched wild individuals in the originator population (total n = 299). We found that a range of innate (lyz, defbl2, il1r-like, tbk1) and adaptive (cd8a, igmh) immunity genes were up-regulated in captivity, accompanied by an increase in expression of the antioxidant enzyme, gpx4a. For some genes previously known to show seasonality in the wild, this appeared to be reduced in captive fishes. Captive fishes tended to express immunity genes, including igzh, foxp3b, lyz, defbl2, and il1r-like, more variably. Furthermore, although gene co-expression patterns (analyzed through gene-by-gene correlations and mutual information theory based networks) shared common structure in wild and captive fishes, there was also significant divergence. For one gene in particular, defbl2, high expression was associated with adverse health outcomes in captive fishes. Taken together, these results demonstrate widespread regulatory changes in the immune system in captive populations, and that the expression of immunity genes is more constrained in the wild. An increase in constitutive systemic immune activity, such as we observed here, may alter the risk of immunopathology and contribute to variance in health in vertebrate populations exposed to anthropogenic environments.

Vitamin D3 affects innate immune status of European sea bass (Dicentrarchus labrax L.).

PubMed

Dioguardi, M; Guardiola, F A; Vazzana, M; Cuesta, A; Esteban, M A; Cammarata, M

2017-08-01

The effects of vitamin D 3 dietary administration on certain innate immune parameters on the expression of immune-related genes in head-kidney (HK) and gut were investigated in European sea bass Dicentrarchus labrax. Vitamin D 3 (vD 3 ) was orally administered to fish in a commercial pellet food supplemented with 0 (control); 3750; 18,750; or 37,500 U kg -1 . Furthermore, gut histology was considered. This study showed a modulation in the activities examined in fish fed with the addition of vD 3 . After just 2 weeks of administration, diet supplementation with the vitamin resulted in increased phagocytic ability, while serum peroxidase content was increased in fish fed with all experimental diets after 4 weeks, no significant differences were observed in protease, anti-protease, natural haemolytic complement activities and total IgM level. At gene level, fbl and rbl transcripts were up-regulated in HK in fish fed with the highest concentration of vD 3 -supplemented diets after 4 weeks, while in the gut, an up-regulation of hep gene was observed in fish fed with the different doses of vD 3 . These results suggest that vD 3 may be of great interest for immunostimulatory purposes in fish farms.

Recombinant expression and purification of the RNA-binding LARP6 proteins from fish genetic model organisms.

PubMed

Castro, José M; Horn, Daniel A; Pu, Xinzhu; Lewis, Karen A

2017-06-01

The RNA-binding proteins that comprise the La-related protein (LARP) superfamily have been implicated in a wide range of cellular functions, from tRNA maturation to regulation of protein synthesis. To more expansively characterize the biological function of the LARP6 subfamily, we have recombinantly expressed the full-length LARP6 proteins from two teleost fish, platyfish (Xiphophorus maculatus) and zebrafish (Danio rerio). The yields of the recombinant proteins were enhanced to >2 mg/L using a tandem approach of an N-terminal His 6 -SUMO tag and an iterative solubility screening assay to identify structurally stabilizing buffer components. The domain topologies of the purified fish proteins were probed with limited proteolysis. The fish proteins contain an internal, protease-resistant 40 kDa domain, which is considerably more stable than the comparable domain from the human LARP6 protein. The fish proteins are therefore a lucrative model system in which to study both the evolutionary divergence of this family of La-related proteins and the structure and conformational dynamics of the domains that comprise the LARP6 protein. Copyright © 2017 Elsevier Inc. All rights reserved.

The threshold induction temperature of the 90-kDa heat shock protein is subject to acclimatization in eurythermal goby fishes (genus Gillichthys).

PubMed Central

Dietz, T J; Somero, G N

1992-01-01

Two extremely eurythermal goby fishes, Gillichthys mirabilis and Gillichthys seta, which encounter habitat temperature variations of approximately 30 degrees C, showed seasonal acclimatization of endogenous levels and of onset temperatures for enhanced synthesis of a 90-kDa-class heat shock protein (HSP90). Summer-acclimatized fishes had higher levels of HSP90 in brain tissue than winter-acclimatized specimens, as shown by Western blot analysis. For winter-acclimatized fishes, increased synthesis of HSP90 was observed when the temperature was raised from a control temperature (18 degrees C) to 28 degrees C. For summer-acclimatized fish, no significantly increased synthesis of HSP90 occurred until the experimental temperature was raised to 32 degrees C. These data suggest that the threshold temperature at which enhanced expression of HSP-encoding genes occurs is not hard-wired genetically but may be subject to acclimatization. A causal relationship between seasonal changes in steady-state levels of HSP90 and the threshold temperature for enhanced HSP90 synthesis is discussed in terms of existing models for the regulation of HSP gene expression. Images PMID:1565632

Identification and expression analysis of zebrafish glypicans during embryonic development.

PubMed

Gupta, Mansi; Brand, Michael

2013-01-01

Heparan sulfate Proteoglycans (HSPG) are ubiquitous molecules with indispensable functions in various biological processes. Glypicans are a family of HSPG's, characterized by a Gpi-anchor which directs them to the cell surface and/or extracellular matrix where they regulate growth factor signaling during development and disease. We report the identification and expression pattern of glypican genes from zebrafish. The zebrafish genome contains 10 glypican homologs, as opposed to six in mammals, which are highly conserved and are phylogenetically related to the mammalian genes. Some of the fish glypicans like Gpc1a, Gpc3, Gpc4, Gpc6a and Gpc6b show conserved synteny with their mammalian cognate genes. Many glypicans are expressed during the gastrulation stage, but their expression becomes more tissue specific and defined during somitogenesis stages, particularly in the developing central nervous system. Existence of multiple glypican orthologs in fish with diverse expression pattern suggests highly specialized and/or redundant function of these genes during embryonic development.

Dietary choline regulates antibacterial activity, inflammatory response and barrier function in the gills of grass carp (Ctenopharyngodon idella).

PubMed

Zhao, Hua-Fu; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu; Feng, Lin

2016-05-01

An 8-week feeding trial was conducted to determine the effects of graded levels of choline (197-1795 mg/kg) on antibacterial properties, inflammatory status and barrier function in the gills of grass carp. The results showed that optimal dietary choline supplementation significantly improved lysozyme and acid phosphatase activities, complement component 3 (C3) content, and the liver expressed antimicrobial peptide 2 and Hepcidin mRNA levels in the gills of fish (P < 0.05). In addition, appropriate dietary choline significantly decreased the oxidative damage, which might be partly due to increase copper, zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR) activities and increased glutathione content in the gills of fish (P < 0.05). Moreover, appropriate dietary choline significantly up-regulated the mRNA levels of interleukin 10 and transforming growth factor β1, Zonula occludens 1, Occludin, Claudin-b, c, 3 and 12, inhibitor of κBα, target of rapamycin, Cu/Zn-SOD, CAT, GR, GPx, GST and NF-E2-related factor 2 in the gills of fish (P < 0.05). Conversely, appropriate dietary choline significantly down-regulated the mRNA levels of pro-inflammatory cytokines, tumor necrosis factor α, interleukin 8, interferon γ, interleukin 1β, and related signaling factors, nuclear factor kappa B p65, IκB kinase β, IκB kinase γ, myosin light chain kinase and Kelch-like-ECH-associated protein 1a (Keap1a) in the gills of fish (P < 0.05). However, choline did not have a significant effect on the mRNA levels of IκB kinase α, Claudin-15 and Keap1b in the gills of fish. Collectively, appropriate dietary choline levels improved gill antibacterial properties and relative gene expression levels of tight junction proteins, and decreased inflammatory status, as well as up-regulated the mRNA levels of related signaling molecules in the gills of fish. Based on gill C3 content and AHR activity, the dietary choline requirements for young grass carp (266.5-787.1 g) were estimated to be 1191.0 and 1555.0 mg/kg diet, respectively. Copyright © 2016. Published by Elsevier Ltd.

Transient expression and activity of human DNA polymerase iota in loach embryos.

PubMed

Makarova, Irina V; Kazakov, Andrey A; Makarova, Alena V; Khaidarova, Nella V; Kozikova, Larisa V; Nenasheva, Valentina V; Gening, Leonid V; Tarantul, Vyacheslav Z; Andreeva, Ludmila E

2012-02-01

Human DNA polymerase iota (Pol ι) is a Y-family DNA polymerase with unusual biochemical properties and not fully understood functions. Pol ι preferentially incorporates dGTP opposite template thymine. This property can be used to monitor Pol ι activity in the presence of other DNA polymerases, e.g. in cell extracts of tissues and tumors. We have now confirmed the specificity and sensitivity of the method of Pol ι activity detection in cell extracts using an animal model of loach Misgurnus fossilis embryos transiently expressing human Pol ι. The overexpression of Pol ι was shown to be accompanied by an increase in abnormalities in development and the frequency of pycnotic nuclei in fish embryos. Further analysis of fish embryos with constitutive or regulated Pol ι expression may provide insights into Pol ι functions in vertebrate animals.

Roles of leptin and ghrelin in adipogenesis and lipid metabolism of rainbow trout adipocytes in vitro.

PubMed

Salmerón, Cristina; Johansson, Marcus; Asaad, Maryam; Angotzi, Anna R; Rønnestad, Ivar; Stefansson, Sigurd O; Jönsson, Elisabeth; Björnsson, Björn Thrandur; Gutiérrez, Joaquim; Navarro, Isabel; Capilla, Encarnación

2015-10-01

Leptin and ghrelin are important regulators of energy homeostasis in mammals, whereas their physiological roles in fish have not been fully elucidated. In the present study, the effects of leptin and ghrelin on adipogenesis, lipolysis and on expression of lipid metabolism-related genes were examined in rainbow trout adipocytes in vitro. Leptin expression and release increased from preadipocytes to mature adipocytes in culture, but did not affect the process of adipogenesis. While ghrelin and its receptor were identified in cultured differentiated adipocytes, ghrelin did not influence either preadipocyte proliferation or differentiation, indicating that it may have other adipose-related roles. Leptin and ghrelin increased lipolysis in mature freshly isolated adipocytes, but mRNA expression of lipolysis markers was not significantly modified. Leptin significantly suppressed the fatty acid transporter-1 expression, suggesting a decrease in fatty acid uptake and storage, but did not affect expression of any of the lipogenesis or β-oxidation genes studied. Ghrelin significantly increased the mRNA levels of lipoprotein lipase, fatty acid synthase and peroxisome proliferator-activated receptor-β, and thus appears to stimulate synthesis of triglycerides as well as their mobilization. Overall, the study indicates that ghrelin, but not leptin seems to be an enhancer of lipid turn-over in adipose tissue of rainbow trout, and this regulation may at least partly be mediated through autocrine/paracrine mechanisms. The mode of action of both hormones needs to be further explored to better understand their roles in regulating adiposity in fish. Copyright © 2015 Elsevier Inc. All rights reserved.

Social regulation of gonadotropin-releasing hormone.

PubMed

White, Stephanie A; Nguyen, Tuan; Fernald, Russell D

2002-09-01

Behavioral interactions among social animals can regulate both reproductive behavior and fertility. A prime example of socially regulated reproduction occurs in the cichlid fish Haplochromis burtoni, in which interactions between males dynamically regulate gonadal function throughout life. This plasticity is mediated by the brain, where neurons that contain the key reproductive regulatory peptide gonadotropin-releasing hormone (GnRH) change size reversibly depending on male social status. To understand how behavior controls the brain, we manipulated the social system of these fish, quantified their behavior and then assessed neural and physiological changes in the reproductive and stress axes. GnRH gene expression was assessed using molecular probes specific for the three GnRH forms in the brain of H. burtoni. We found that perception of social opportunity to increase status by a male leads to heightened aggressiveness, to increased expression of only one of the three GnRH forms and to increases in size of GnRH-containing neurons and of the gonads. The biological changes characteristic of social ascent happen faster than changes following social descent. Interestingly, behavioral changes show the reverse pattern: aggressive behaviors emerge more slowly in ascending animals than they disappear in descending animals. Although the gonads and GnRH neurons undergo similar changes in female H. burtoni, regulation occurs via endogenous rather than exogenous social signals. Our data show that recognition of social signals by males alters stress levels, which may contribute to the alteration in GnRH gene expression in particular neurons essential for the animal to perform in its new social status.

Identification of centrarchid hepcidins and evidence that 17β-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides)

USGS Publications Warehouse

Robertson, L.S.; Iwanowicz, L.R.; Marranca, J.M.

2009-01-01

Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormone. Both hepcidins are predominately expressed in the liver of largemouth bass, similar to other fish and mammals. Experimental exposure of pond-raised largemouth bass to 17β-estradiol and/or the bacteria Edwardsiella ictaluri led to distinct changes in expression of hep-1 and hep-2. Estradiol reduced the constitutive expression of hep-1 in the liver. Bacterial exposure induced expression of hep-2, suggesting that hepcidin-2 may have an antimicrobial function, and this induction was abolished by estradiol. To our knowledge, this is the first report of the regulation of hepcidin expression by estradiol in either fish or mammals.

Identification of centrarchid hepcidins and evidence that 17beta-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (Micropterus salmoides).

PubMed

Robertson, Laura S; Iwanowicz, Luke R; Marranca, Jamie Marie

2009-06-01

Hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. Here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Hepcidin-1 contains a putative ATCUN metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormone. Both hepcidins are predominately expressed in the liver of largemouth bass, similar to other fish and mammals. Experimental exposure of pond-raised largemouth bass to 17beta-estradiol and/or the bacteria Edwardsiella ictaluri led to distinct changes in expression of hep-1 and hep-2. Estradiol reduced the constitutive expression of hep-1 in the liver. Bacterial exposure induced expression of hep-2, suggesting that hepcidin-2 may have an antimicrobial function, and this induction was abolished by estradiol. To our knowledge, this is the first report of the regulation of hepcidin expression by estradiol in either fish or mammals.

Stocking density affects the growth performance and metabolism of Amur sturgeon by regulating expression of genes in the GH/IGF axis

NASA Astrophysics Data System (ADS)

Ren, Yuanyuan; Wen, Haishen; Li, Yun; Li, Jifang

2017-07-01

The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three different stocking densities (low stocking density, LSD: 5.5 kg/m3; medium stocking density, MSD: 8.0 kg/m3; and high stocking density, HSD: 11.0 kg/m3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower final body weight and specific growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2 (IGF-2), while the concentrations of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-1) decreased in the HSD group. The full-length cDNAs of GH and IGF-2 genes (995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor (GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively affects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.

Use of Hybridization Chain Reaction-Fluorescent In Situ Hybridization To Track Gene Expression by Both Partners during Initiation of Symbiosis.

PubMed

Nikolakakis, K; Lehnert, E; McFall-Ngai, M J; Ruby, E G

2015-07-01

The establishment of a productive symbiosis between Euprymna scolopes, the Hawaiian bobtail squid, and its luminous bacterial symbiont, Vibrio fischeri, is mediated by transcriptional changes in both partners. A key challenge to unraveling the steps required to successfully initiate this and many other symbiotic associations is characterization of the timing and location of these changes. We report on the adaptation of hybridization chain reaction-fluorescent in situ hybridization (HCR-FISH) to simultaneously probe the spatiotemporal regulation of targeted genes in both E. scolopes and V. fischeri. This method revealed localized, transcriptionally coregulated epithelial cells within the light organ that responded directly to the presence of bacterial cells while, at the same time, provided a sensitive means to directly show regulated gene expression within the symbiont population. Thus, HCR-FISH provides a new approach for characterizing habitat transition in bacteria and for discovering host tissue responses to colonization. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Cloning and characterization of microsomal triglyceride transfer protein gene and its potential connection with peroxisome proliferator-activated receptor (PPAR) in blunt snout bream (Megalobrama amblycephala).

PubMed

Li, Jun-Yi; Zhang, Ding-Dong; Jiang, Guang-Zhen; Li, Xiang-Fei; Zhang, Chun-Nuan; Zhou, Man; Liu, Wen-Bin; Xu, Wei-Na

2015-11-01

Microsomal triglyceride transfer protein (MTTP), a major intracellular protein capable of transferring neutral lipids, plays a pivotal role in the assembly and secretion of apolipoprotein B-containing lipoproteins. In this study, MTTP cDNA was firstly cloned from the liver of blunt snout bream (Megalobrama amblycephala), the full-length cDNA covered 3457-bp with an open reading frame of 2661-bp, which encodes 886 amino acids, including a putative signal peptide of 24 amino acids long. After the feeding trial, a graded tissue-specific expression pattern of MTTP was observed and high expression abundance in the liver and intestine indicated its major function in lipid transport in this fish species. In addition, expression of genes encoding MTTP as well as peroxisome proliferator-activated receptor (PPAR), which are transcription factors and serve as key regulators in lipid homoeostasis, was all affected by dietary lipid and choline supplementations. Elevated dietary lipid levels significantly increased the liver, intestinal and muscle MTTP mRNA abundance. Additionally, the down-regulation of MTTP expression in the liver and muscle was observed when fish were fed with inadequate choline supplementation in high-fat diet, yet up-regulated as supplementing extra choline in diet. Expressions of PPARα and PPARβ in the liver and muscle showed similar trend of MTTP expression. The results suggested the potential connection of MTTP and PPAR in response to different dietary nutritional factors. Furthermore, extra choline supplementations could promote lipid transfer and enhance fatty acid oxidation, which indicated a molecular mechanism of choline on diminishing fat accumulation in blunt snout bream. Copyright © 2015 Elsevier Inc. All rights reserved.

Cloning and Characterization of Lxr and Srebp1, and Their Potential Roles in Regulation of LC-PUFA Biosynthesis in Rabbitfish Siganus canaliculatus.

PubMed

Zhang, Qinghao; You, Cuihong; Liu, Fang; Zhu, Wendi; Wang, Shuqi; Xie, Dizhi; Monroig, Óscar; Tocher, Douglas R; Li, Yuanyou

2016-09-01

Rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the ability to biosynthesize C20-22 long-chain polyunsaturated fatty acid (LC-PUFA) from C18 PUFA precursors, which is generally absent or low in marine teleosts. Thus, understanding the molecular basis of LC-PUFA biosynthesis in rabbitfish will contribute to efforts aimed at optimizing LC-PUFA biosynthesis in teleosts, especially marine species. In the present study, the importance of the transcription factors liver X receptor (Lxr) and sterol regulatory element-binding protein 1 (Srebp1) in regulation of LC-PUFA biosynthesis in rabbitfish was investigated. First, full-length cDNA of Lxr and Srebp1 were cloned and characterized. The Lxr mRNA displayed a ubiquitous tissue expression pattern while Srebp1 was highly expressed in eyes, brain and intestine. In rabbitfish primary hepatocytes treated with Lxr agonist T0901317, the expression of Lxr and Srebp1 was activated, accompanied by elevated mRNA levels of Δ4 and Δ6/Δ5 fatty acyl desaturase (Fad), key enzymes of LC-PUFA biosynthesis, as well as peroxisome proliferator-activated receptor γ (PPARγ). In addition, Srebp1 displayed higher expression levels in liver of rabbitfish fed a vegetable oil diet or reared at 10 ppt salinity, which were conditions reported to increase the liver expression of Δ4 and Δ6/Δ5 Fad and LC-PUFA biosynthetic ability, than fish fed a fish oil diet or reared at 32 ppt, respectively. These results suggested that Lxr and Srebp1 are involved in regulation of LC-PUFA biosynthesis probably by promoting the expression of two Fad in rabbitfish liver, which, to our knowledge, is the first report in marine teleosts.

9 CFR 83.4 - VHS-regulated fish and VHS-regulated areas.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false VHS-regulated fish and VHS-regulated... HEMORRHAGIC SEPTICEMIA § 83.4 VHS-regulated fish and VHS-regulated areas. (a)(1) APHIS will list as a VHS-regulated fish any fish species found in freshwater to be susceptible to the North American (type IV) strain...

Evidence for Leptin Expression in Fishes

PubMed Central

JOHNSON, RANDY M.; JOHNSON, TRICIA M.; LONDRAVILLE, RICHARD L.

2012-01-01

Tissues from bony fish were screened with anti-mouse leptin antibodies to detect the presence of the fat-regulating hormone in fishes. Low molecular-weight (16 kDa) immunoreactive bands were detected in blood, brain, heart and liver of green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), largemouth bass (Micropterus salmoides), white crappie (Pomonix annularis), channel catfish (Ictalurus punctatus), and rainbow trout (Oncorhynchus mykiss). To further verify that we had identified leptin, the response of fish “leptin” was measured in fed and fasted green sunfish. Fed sunfish had approximately threefold higher concentration of leptin in blood than did fasted sunfish (fed vs. fasted; 0.599 ± 0.03 μg/μl vs. 0.196 ± 0.04 μg/μl; P > F = 0.0001), which is consistent with mammalian models of leptin function. Brain leptin concentration is also positively correlated with percent body fat in white crappie and bluegill. Based upon electrophoretic mobility, immunoreactivity, response to fasting, and correlation with adiposity, we believe we have the first evidence for leptin expression in an ectotherm. PMID:10797324

Self-association of Gata1 enhances transcriptional activity in vivo in zebra fish embryos.

PubMed

Nishikawa, Keizo; Kobayashi, Makoto; Masumi, Atsuko; Lyons, Susan E; Weinstein, Brant M; Liu, P Paul; Yamamoto, Masayuki

2003-11-01

Gata1 is a prototype transcription factor that regulates hematopoiesis, yet the molecular mechanisms by which Gata1 transactivates its target genes in vivo remain unclear. We previously showed, in transgenic zebra fish, that Gata1 autoregulates its own expression. In this study, we characterized the molecular mechanisms for this autoregulation by using mutations in the Gata1 protein which impair autoregulation. Of the tested mutations, replacement of six lysine residues with alanine (Gata1KA6), which inhibited self-association activity of Gata1, reduced the Gata1-dependent induction of reporter gene expression driven by the zebra fish gata1 hematopoietic regulatory domain (gata1 HRD). Furthermore, overexpression of wild-type Gata1 but not Gata1KA6 rescued the expression of Gata1 downstream genes in vlad tepes, a germ line gata1 mutant fish. Interestingly, both GATA sites in the double GATA motif in gata1 HRD were critical for the promoter activity and for binding of the self-associated Gata1 complex, whereas only the 3'-GATA site was required for Gata1 monomer binding. These results thus provide the first in vivo evidence that the ability of Gata1 to self-associate critically contributes to the autoregulation of the gata1 gene.

Constitutive expression of thymidylate synthase from LCDV-C induces a transformed phenotype in fish cells.

PubMed

Zhao, Zhe; Shi, Yan; Ke, Fei; Wei, Sun; Gui, Jianfang; Zhang, Qiya

2008-03-01

Thymidylate synthase (TS), an essential enzyme in DNA synthesis and repair, plays a key role in the events of cell cycle regulation and tumor formation. Here, an investigation was presented about subcellular location and biological function of viral TS from lymphocystis disease virus from China (LCDV-C) in fish cells. Fluorescence microscopy revealed that LCDV-C TS was predominantly localized in the cytoplasm in fish cells. Cell cycle analysis demonstrated that LCDV-C TS promoted cell cycle progression into S and G2/M phase in the constitutive expressed cells. As a result, the cells have a faster growth rate compared with the control cells as revealed by cell growth curves. For foci assay, the TS-expressed cells gave rise to foci 4-5 weeks after incubation. Microscopic examination of the TS-induced foci revealed multilayered growth and crisscross morphology characteristic of transformed cells. Moreover, LCDV-C TS predisposed the transfected cells to acquire an anchorage-independent phenotype and could grow in 0.3% soft agar. So the data reveal LCDV-C TS is sufficient to induce a transformed phenotype in fish cells in vitro and exhibits its potential ability in cell transformation. To our knowledge, it is the first report on viral TS sequences associated with transforming activity.

Genetic background and embryonic temperature affect DNA methylation and expression of myogenin and muscle development in Atlantic salmon (Salmo salar)

PubMed Central

Burgerhout, Erik; Mommens, Maren; Johnsen, Hanne; Aunsmo, Arnfinn; Santi, Nina

2017-01-01

The development of ectothermic embryos is strongly affected by incubation temperature, and thermal imprinting of body growth and muscle phenotype has been reported in various teleost fishes. The complex epigenetic regulation of muscle development in vertebrates involves DNA methylation of the myogenin promoter. Body growth is a heritable and highly variable trait among fish populations that allows for local adaptations, but also for selective breeding. Here we studied the epigenetic effects of embryonic temperature and genetic background on body growth, muscle cellularity and myogenin expression in farmed Atlantic salmon (Salmo salar). Eggs from salmon families with either high or low estimated breeding values for body growth, referred to as Fast and Slow genotypes, were incubated at 8°C or 4°C until the embryonic ‘eyed-stage’ followed by rearing at the production temperature of 8°C. Rearing temperature strongly affected the growth rates, and the 8°C fish were about twice as heavy as the 4°C fish in the order Fast8>Slow8>Fast4>Slow4 prior to seawater transfer. Fast8 was the largest fish also at harvest despite strong growth compensation in the low temperature groups. Larval myogenin expression was approximately 4–6 fold higher in the Fast8 group than in the other groups and was associated with relative low DNA methylation levels, but was positively correlated with the expression levels of the DNA methyltransferase genes dnmt1, dnmt3a and dnmt3b. Juvenile Fast8 fish displayed thicker white muscle fibres than Fast4 fish, while Slow 8 and Slow 4 showed no difference in muscle cellularity. The impact of genetic background on the thermal imprinting of body growth and muscle development in Atlantic salmon suggests that epigenetic variation might play a significant role in the local adaptation to fluctuating temperatures over short evolutionary time. PMID:28662198

Genetic background and embryonic temperature affect DNA methylation and expression of myogenin and muscle development in Atlantic salmon (Salmo salar).

PubMed

Burgerhout, Erik; Mommens, Maren; Johnsen, Hanne; Aunsmo, Arnfinn; Santi, Nina; Andersen, Øivind

2017-01-01

The development of ectothermic embryos is strongly affected by incubation temperature, and thermal imprinting of body growth and muscle phenotype has been reported in various teleost fishes. The complex epigenetic regulation of muscle development in vertebrates involves DNA methylation of the myogenin promoter. Body growth is a heritable and highly variable trait among fish populations that allows for local adaptations, but also for selective breeding. Here we studied the epigenetic effects of embryonic temperature and genetic background on body growth, muscle cellularity and myogenin expression in farmed Atlantic salmon (Salmo salar). Eggs from salmon families with either high or low estimated breeding values for body growth, referred to as Fast and Slow genotypes, were incubated at 8°C or 4°C until the embryonic 'eyed-stage' followed by rearing at the production temperature of 8°C. Rearing temperature strongly affected the growth rates, and the 8°C fish were about twice as heavy as the 4°C fish in the order Fast8>Slow8>Fast4>Slow4 prior to seawater transfer. Fast8 was the largest fish also at harvest despite strong growth compensation in the low temperature groups. Larval myogenin expression was approximately 4-6 fold higher in the Fast8 group than in the other groups and was associated with relative low DNA methylation levels, but was positively correlated with the expression levels of the DNA methyltransferase genes dnmt1, dnmt3a and dnmt3b. Juvenile Fast8 fish displayed thicker white muscle fibres than Fast4 fish, while Slow 8 and Slow 4 showed no difference in muscle cellularity. The impact of genetic background on the thermal imprinting of body growth and muscle development in Atlantic salmon suggests that epigenetic variation might play a significant role in the local adaptation to fluctuating temperatures over short evolutionary time.

Perspectives on fish gonadotropins and their receptors.

PubMed

Levavi-Sivan, B; Bogerd, J; Mañanós, E L; Gómez, A; Lareyre, J J

2010-02-01

Teleosts lack a hypophyseal portal system and hence neurohormones are carried by nerve fibers from the preoptic region to the pituitary. The various cell types in the teleost pituitary are organized in discrete domains. Fish possess two gonadotropins (GtH) similar to FSH and LH in other vertebrates; they are heterodimeric hormones that consist of a common alpha subunit non-covalently associated with a hormone-specific beta subunit. In recent years the availability of molecular cloning techniques allowed the isolation of the genes coding for the GtH subunits in 56 fish species representing at least 14 teleost orders. Advanced molecular engineering provides the technology to produce recombinant GtHs from isolated cDNAs. Various expression systems have been used for the production of recombinant proteins. Recombinant fish GtHs were produced for carp, seabream, channel and African catfish, goldfish, eel, tilapia, zebrafish, Manchurian trout and Orange-spotted grouper. The hypothalamus in fishes exerts its regulation on the release of the GtHs via several neurohormones such as GnRH, dopamine, GABA, PACAP, IGF-I, norepinephrine, NPY, kisspeptin, leptin and ghrelin. In addition, gonadal steroids and peptides exert their effects on the gonadotropins either directly or via the hypothalamus. All these are discussed in detail in this review. In mammals, the biological activities of FSH and LH are directed to different gonadal target cells through the cell-specific expression of the FSH receptor (FSHR) and LH receptor (LHR), respectively, and the interaction between each gonadotropin-receptor couple is highly selective. In contrast, the bioactivity of fish gonadotropins seems to be less specific as a result of promiscuous hormone-receptor interactions, while FSHR expression in Leydig cells explains the strong steroidogenic activity of FSH in certain fish species. Copyright 2009 Elsevier Inc. All rights reserved.

Anti-inflammatory effects of fish oil in ovaries of laying hens target prostaglandin pathways.

PubMed

Eilati, Erfan; Small, Carolynn C; McGee, Stacey R; Kurrey, Nawneet K; Hales, Dale Buchanan

2013-10-24

An effective way to control cancer is by prevention. Ovarian cancer is the most lethal gynecological malignancy. Progress in the treatment and prevention of ovarian cancer has been hampered due to the lack of an appropriate animal model and absence of effective chemo-prevention strategies. The domestic hens spontaneously develop ovarian adenocarcinomas that share similar histological appearance and symptoms such as ascites and metastasis with humans. There is a link between chronic inflammation and cancer. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. PGE2 exerts its effects on target cells by coupling to four subtypes of receptors which have been classified as EP1-4. Fish oil is a source of omega-3 fatty acids (OM-3FAs) which may be effective in prevention of ovarian cancer. Our objective was to assess the potential impact of fish oil on expression of COX enzymes, PGE2 concentration, apoptosis and proliferation in ovaries of laying hens. 48 white Leghorn hens were fed 50, 100, 175, 375 and 700 mg/kg fish oil for 21 days. The OM3-FAs and omega-6 fatty acids contents of egg yolks were determined by Gas Chromatography. Proliferation, apoptosis, COX-1, COX-2 and prostaglandin receptor subtype 4 (EP4) protein and mRNA expression and PGE2 concentration in ovaries were measured by PCNA, TUNEL, Western blot, quantitative real-time qPCR and ELISA, respectively. Consumption of fish oil increased the incorporation of OM-3FAs into yolks and decreased both COX-1 and COX-2 protein and mRNA expression. In correlation with COXs down-regulation, fish oil significantly reduced the concentrations of PGE2 in ovaries. EP4 protein and mRNA expression in ovaries of hens was not affected by fish oil treatment. A lower dose of fish oil increased the egg laying frequency. 175 and 700 mg/kg fish oil reduced proliferation and 700 mg/kg increased apoptosis in hen ovaries. Our findings suggest that the lower doses of fish oil reduce inflammatory PG and may be an effective approach in preventing ovarian carcinogenesis. These findings may provide the basis for clinical trials utilizing fish oil as a dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.

Acute transcriptional up-regulation specific to osteoblasts/osteoclasts in medaka fish immediately after exposure to microgravity

PubMed Central

Chatani, Masahiro; Morimoto, Hiroya; Takeyama, Kazuhiro; Mantoku, Akiko; Tanigawa, Naoki; Kubota, Koji; Suzuki, Hiromi; Uchida, Satoko; Tanigaki, Fumiaki; Shirakawa, Masaki; Gusev, Oleg; Sychev, Vladimir; Takano, Yoshiro; Itoh, Takehiko; Kudo, Akira

2016-01-01

Bone loss is a serious problem in spaceflight; however, the initial action of microgravity has not been identified. To examine this action, we performed live-imaging of animals during a space mission followed by transcriptome analysis using medaka transgenic lines expressing osteoblast and osteoclast-specific promoter-driven GFP and DsRed. In live-imaging for osteoblasts, the intensity of osterix- or osteocalcin-DsRed fluorescence in pharyngeal bones was significantly enhanced 1 day after launch; and this enhancement continued for 8 or 5 days. In osteoclasts, the signals of TRAP-GFP and MMP9-DsRed were highly increased at days 4 and 6 after launch in flight. HiSeq from pharyngeal bones of juvenile fish at day 2 after launch showed up-regulation of 2 osteoblast- and 3 osteoclast- related genes. Gene ontology analysis for the whole-body showed that transcription of genes in the category “nucleus” was significantly enhanced; particularly, transcription-regulators were more up-regulated at day 2 than at day 6. Lastly, we identified 5 genes, c-fos, jun-B-like, pai-1, ddit4 and tsc22d3, which were up-regulated commonly in the whole-body at days 2 and 6, and in the pharyngeal bone at day 2. Our results suggested that exposure to microgravity immediately induced dynamic alteration of gene expression levels in osteoblasts and osteoclasts. PMID:28004797

RING domain is essential for the antiviral activity of TRIM25 from orange spotted grouper.

PubMed

Yang, Ying; Huang, Youhua; Yu, Yepin; Yang, Min; Zhou, Sheng; Qin, Qiwei; Huang, Xiaohong

2016-08-01

Tripartite motif-containing 25 (TRIM25) has been demonstrated to exert crucial roles in the regulation of innate immune signaling. However, the roles of fish TRIM25 in antiviral immune response still remained uncertain. Here, a novel fish TRIM25 gene from orange spotted grouper (EcTRIM25) was cloned and its roles in grouper virus infection were elucidated. EcTRIM25 encoded a 734-aa protein which shared 68% identity to large yellow croaker (Larimichthys crocea). Amino acid alignment showed that EcTRIM25 contained three conserved domains, including a RING-finger domain, a B box/coiled-coil domain and a SPRY domain. In healthy grouper, the transcript of EcTRIM25 was predominantly detected in skin, spleen and intestine. After stimulation with Singapore grouper iridovirus (SGIV) or poly I:C, the relative expression of EcTRIM25 in grouper spleen was significantly increased at the early stage of injection. Subcellular localization analysis showed that EcTRIM25 distributed throughout the cytoplasm in grouper cells. Notably, the deletion RING domain affected its accurate localization and displayed microtubule like structures or bright aggregates in GS cells. After incubation with SGIV or red spotted grouper nervous necrosis virus (RGNNV), overexpression of full length of EcTRIM25 in vitro significantly decreased the viral gene transcription of SGIV and RGNNV. Consistently, the deletion of RING domain obviously affected the inhibitory effect of EcTRIM25. Furthermore, overexpression of EcTRIM25 significantly increased the expression level of interferon related signaling molecules, including interferon regulatory factor (IRF) 3, interferon-induced 35-kDa protein (IFP35), MXI, IRF7 and myeloid differentiation factor 88 (MyD88), suggesting that the positive regulation of interferon immune response by EcTRIM25 might affected RGNNV replication directly. Meanwhile, the expression levels of pro-inflammation cytokines were differently regulated by the ectopic expression of EcTRIM25. We proposed that the regulation of IRF7, MyD88 and pro-inflammation cytokines might contribute more important roles in SGIV infection. In addition, the RING domain of EcTRIM25 also played critical roles in the regulation of interferon immune and inflammation response. Together, our results will provide new evidences that the RING domain was essential for the antiviral action of fish TRIM25 against iridovirus and nodavirus infection. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of complex water pollution with heavy metals and Pyrethroid pesticides on transcript levels of metallothionein and immune related genes.

PubMed

Ghazy, Haneen A; Abdel-Razek, Mohamed A S; El Nahas, Abeer F; Mahmoud, Shawky

2017-09-01

Alteration of immunological function of an aquatic organism can be used as an indicator for evaluating the direct effect of exposure to pollutants. The aim of this work is to assess the impact of complex water pollution with special reference to Pyrethroid pesticides and heavy metals on mRNA transcript levels of Metallothionine and some immune related genes of Nile tilapia (Oreochromas Niloticus). Residues of six heavy metals and six Pyrethroid were assessed in water as well as fish tissues at three different sites of Lake Burullus, located at Northern Egypt. Variations of water physicochemical properties associated with different levels of heavy metals at the three different sections were recorded. Tissue residues of Fe, Mn and Zn, Cu, Ni exceed water levels in contrast to elevated water level of Pb. All assessed Pyrethroids are detected in fish tissue samples with higher concentration (3-42 folds) than that found in water samples especially Cypermethrin. Significant down-regulation of expression levels of metallothionein (MT) at the three sections of the lake was observed. The expression of immune related genes (IgM) and inflammatory cytokines (TNF, IL.8 and IL.1) were affected. IgM and TNF were significantly down-regulated at eastern and western section of the lake; meanwhile the expression of IL8 is down regulated at the three sections of the lack. IL1 was significantly up-regulated at eastern and middle sections. We conclude that, variable gene expression of MT and immune-related genes at the three sections of the lack impose different response to complex water pollution in relation to variable aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential expression of myogenic regulatory factor MyoD in pacu skeletal muscle (Piaractus mesopotamicus Holmberg 1887: Serrasalminae, Characidae, Teleostei) during juvenile and adult growth phases.

PubMed

de Almeida, Fernanda Losi Alves; Carvalho, Robson Francisco; Pinhal, Danillo; Padovani, Carlos Roberto; Martins, Cesar; Dal Pai-Silva, Maeli

2008-12-01

Skeletal muscle is the edible part of the fish. It grows by hypertrophy and hyperplasia, events regulated by differential expression of myogenic regulatory factors (MRFs). The study of muscle growth mechanisms in fish is very important in fish farming development. Pacu (Piaractus mesopotamicus) is one of the most important food species farmed in Brazil and has been extensively used in Brazilian aquaculture programs. The aim of this study was to analyze hyperplasia and hypertrophy and the MRF MyoD expression pattern in skeletal muscle of pacu (P. mesopotamicus) during juvenile and adult growth stages. Juvenile (n=5) and adult (n=5) fish were anaesthetized, sacrificed, and weight (g) and total length (cm) determined. White dorsal region muscle samples were collected and immersed in liquid nitrogen. Transverse sections (10 microm thick) were stained with Haematoxilin-Eosin (HE) for morphological and morphometric analysis. Smallest fiber diameter from 100 muscle fibers per animal was calculated in each growth phase. These fibers were grouped into three classes (<20, 20-50, and >50 microm) to evaluate hypertrophy and hyperplasia in white skeletal muscle. MyoD gene expression was determined by semi-quantitative RT-PCR. PCR products were cloned and sequenced. Juvenile and adult pacu skeletal muscle had similar morphology. The large number of <20 microm diameter muscle fibers observed in juvenile fish confirms active hyperplasia. In adult fish, most fibers were over 50 microm diameter and denote more intense muscle fiber hypertrophy. The MyoD mRNA level in juveniles was higher than in adults. A consensus partial sequence for MyoD gene (338 base pairs) was obtained. The Pacu MyoD nucleotide sequence displayed high similarity among several vertebrates, including teleosts. The differential MyoD gene expression observed in pacu white muscle is possibly related to differences in growth patterns during the phases analyzed, with hyperplasia predominant in juveniles and hypertrophy in adult fish. These results should provide a foundation for understanding the molecular control of skeletal muscle growth in economically important Brazilian species, with a view to improving production quality.

Modulation of telomerase activity in fish muscle by biological and environmental factors.

PubMed

Peterson, Drew Ryan; Mok, Helen Oi Lam; Au, Doris Wai Ting

2015-12-01

Telomerase expression has long been linked to promotion of tumor growth and cell proliferation in mammals. Interestingly, telomerase activity (TA) has been detected in skeletal muscle for a variety of fish species. Despite this being a unique feature in fish, very few studies have investigated the potential role of TA in muscle. The present study was set to prove the concepts that muscle telomerase in fish is related to body growth, and more specifically, to muscle cell proliferation and apoptosis in vivo. Moreover, muscle TA can be influenced by biotic factors and modulated by environmental stress. Using three fish species, mangrove red snapper (Lutjanus argentimaculatus), orange-spotted grouper (Epinephelus coioides), and marine medaka (Oryzias melastigma), the present work reports for the first time that fish muscle TA was sensitive to the environmental stresses of starvation, foodborne exposure to benzo[a]pyrene, and hypoxia. In marine medaka, muscle TA was coupled with fish growth during early life stages. Upon sexual maturation, muscle TA was confounded by sex (female>male). Muscle TA was significantly correlated with telomerase reverse transcriptase (TERT) protein expression (Pearson correlation r=0.892; p≤0.05), which was coupled with proliferating cell nuclear antigen (PCNA) cell proliferation, but not associated with apoptosis (omBax/omBcl2 ratio) in muscle tissue. The results reported here have bridged the knowledge gap between the existence and function of telomerase in fish muscle. The underlying regulatory mechanisms of muscle TA in fish warrant further exploration for comparison with telomerase regulation in mammals. Copyright © 2015 Elsevier Inc. All rights reserved.

CLONING AND EXPRESSION OF THE TRANSLOCATOR PROTEIN (18 KDA), VOLTAGE-DEPENDENT ANION CHANNEL, AND DIAZEPAM BINDING INHIBITOR IN THE GONAD OF LARGEMOUTH BASS (MICROPTERUS SALMOIDES) ACROSS THE REPRODUCTIVE CYCLE

PubMed Central

Doperalski, Nicholas J.; Martyniuk, Christopher J.; Prucha, Melinda S.; Kroll, Kevin J.; Denslow, Nancy D.; Barber, David S.

2011-01-01

Cholesterol transport across the mitochondrial membrane is rate-limiting for steroidogenesis in vertebrates. Previous studies in fish have characterized expression of the steroidogenic acute regulatory protein, however the function and regulation of other genes and proteins involved in piscine cholesterol transport have not been evaluated. In the current study, mRNA sequences of the 18 kDa translocator protein (tspo; formerly peripheral benzodiazepine receptor), voltage-dependent anion channel (vdac), and diazepam binding inhibitor (dbi; also acyl-CoA binding protein) were cloned from largemouth bass. Gonadal expression was examined across reproductive stages to determine if expression is correlated with changes in steroid levels and with indicators of reproductive maturation. In testis, transcript abundance of tspo and dbi increased with reproductive maturation (6- and 23-fold maximal increase, respectively) and expression of tspo and dbi was positively correlated with reproductive stage, gonadosomatic index (GSI), and circulating levels of testosterone. Testis vdac expression was positively correlated with reproductive stage and GSI. In females, gonadal tspo and vdac expression was negatively correlated with GSI and levels of plasma testosterone and 17β-estradiol. Ovarian dbi expression was not correlated with indicators of reproductive maturation. These studies represent the first investigation of the steroidogenic role of tspo, vdac, and dbi in fish. Findings suggest that cholesterol transport in largemouth bass testis, but not ovary, may be transcriptionally-regulated, however further investigation will be necessary to fully elucidate the role of these genes in largemouth bass steroidogenesis. PMID:21600210

Identification of a single p19 gene and three p40 paralogues in grass carp (Ctenopharyngodon idellus): Their potential for the formation of interleukin 23 and inducible expression in vitro and in vivo.

PubMed

Wang, Xinyan; Qin, Lei; Du, Linyong; Chen, Di; Zhang, Anying; Yang, Kun; Zhou, Hong

2017-12-01

Interleukin (IL-) 23, a member of IL-12 family, is a composite cytokine with the subunits of p19 and p40. Although IL-12 and IL-23 share the p40 subunit, they play vastly different roles in immune regulation. In teleost, much emphasis has been placed on the identification of IL-12, but evidence for the existence of IL-23 is still lacking. In the present study, a p19 gene and three p40 paralogues were isolated and identified from grass carp, suggesting multiple assembly of IL-23 molecules in fish species. To address this issue, the existence of different p19/p40 heterodimers were examined by Co-Immunoprecipitation (Co-IP) assay, showing that only co-expression of p19 and each p40 subunit could produce the soluble proteins corresponding to three IL-23 isoforms. Additionally, bacterial infection could up-regulate the mRNA expression of p19, p40a and p40b but not p40c in head kidney, indicating distinct expression patterns of three p40 paralogues. Moreover, in vitro experiments demonstrated that both B-cell stimulator, LPS and T-cell mitogen, PHA markedly increased the mRNA levels of p19 and three p40 paralogues in grass carp periphery blood lymphocytes (PBLs). The simultaneous up-regulation of mRNA expression of p19 and p40 paralogues in response to immune stimuli supports the idea that p19 may form heterodimeric molecules with three p40 subunits in grass carp under immune activation. These findings for the first time highlight the potential of p19 and p40 for dimerization in fish, particularly the existence of three IL-23 isoforms as soluble heterodimeric cytokines in grass carp, thereby providing the basis for further investigating the function of IL-23 in fish immunity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shared Physiological and Molecular Responses in Marine Fish and Invertebrates to Environmental Hypoxia: Potential Biomarkers of Adverse Impacts on Marine Communities

NASA Astrophysics Data System (ADS)

Thomas, P.; Rahman, S.

2016-02-01

Knowledge of the effects of environmental exposure to hypoxia (dissolved oxygen: <2 mg/L) on critical physiological functions such as reproduction, growth and metabolism in both fish and invertebrates is essential for accurate predictions of its chronic impacts on marine communities. Marked disruption of reproduction and its endocrine control was observed in Atlantic croaker collected from the hypoxic region in the northern Gulf of Mexico. Recent research has shown that growth and its physiological upregulation is also impaired in hypoxia-exposed marine fish. Expression of insulin-like growth factor (IGF) binding protein (IGFBP), which inhibits growth, was increased in croaker livers, whereas plasma levels of IGF, the primary regulator of growth, were decreased in snapper after hypoxia exposure. In addition, hypoxia inducible factor-1 (HIF-1), which regulates changes in metabolism during adaptation to hypoxia, was upregulated in croaker collected from hypoxic environments. Interestingly, similar changes in the expression of IGFBP and HIF-1 have been found in marine crustaceans after hypoxia exposure, suggesting these responses to hypoxia are common to marine fish and invertebrates. Preliminary field studies indicate that hypoxia exposure also causes epigenetic modifications, including increases in global DNA methylation, and that these epigenetic changes can influence reproduction and growth in croaker. Epigenetic modifications can be passed to offspring and persist in future generations no longer exposed to an environmental stressor further aggravating its long-term adverse impacts on population abundance and delaying recovery. The growing availability of complete invertebrate genomes and high-throughput DNA sequencing indicates similar epigenetic studies can now be conducted with marine invertebrates. Collectively, the results indicate that environmental hypoxia exposure disrupts major physiological functions in fish and invertebrates critical for maintenance of their populations.

Zymosan-induced immune challenge modifies the stress response of hypoxic air-breathing fish (Anabas testudineus Bloch): Evidence for reversed patterns of cortisol and thyroid hormone interaction, differential ion transporter functions and non-specific immune response.

PubMed

Simi, S; Peter, Valsa S; Peter, M C Subhash

2017-09-15

Fishes have evolved physiological mechanisms to exhibit stress response, where hormonal signals interact with an array of ion transporters and regulate homeostasis. As major ion transport regulators in fish, cortisol and thyroid hormones have been shown to interact and fine-tune the stress response. Likewise, in fishes many interactions have been identified between stress and immune components, but the physiological basis of such interaction has not yet delineated particularly in air-breathing fish. We, therefore, investigated the responses of thyroid hormones and cortisol, ion transporter functions and non-specific immune response of an obligate air-breathing fish Anabas testudineus Bloch to zymosan treatment or hypoxia stress or both, to understand how immune challenge modifies the pattern of stress response in this fish. Induction of experimental peritonitis in these fish by zymosan treatment (200ngg -1 ) for 24h produced rise in respiratory burst and lysozomal activities in head kidney phagocytes. In contrast, hypoxia stress for 30min in immune-challenged fish reversed these non-specific responses of head kidney phagocytes. The decline in plasma cortisol in zymosan-treated fish and its further suppression by hypoxia stress indicate that immune challenge suppresses the cortisol-driven stress response of this fish. Likewise, the decline in plasma T 3 and T 4 after zymosan-treatment and the rise in plasma T 4 after hypoxia stress in immune-challenged fish indicate a critical role for thyroid hormone in immune-stress response due to its differential sensitivity to both immune and stress challenges. Further, analysis of the activity pattern of ion-dependent ATPases viz. Na + /K + -ATPase, H + /K + -ATPase and Na + /NH 4 + -ATPase indicates a functional interaction of ion transport system with the immune response as evident in its differential and spatial modifications after hypoxia stress in immune-challenged fish. The immune-challenge that produced differential pattern of mRNA expression of Na + /K + -ATPase α-subunit isoforms; nkaα1a, nkaα1b and nkaα1c and the shift in nkaα1a and nkaα1b isoforms expression after hypoxia stress in immune-challenged fish, presents transcriptomic evidence for a modified Na + /K + ion transporter system in these fish. Collectively, our data thus provide evidence for an interactive immune-stress response in an air-breathing fish, where the patterns of cortisol-thyroid hormone interaction, the ion transporter functions and the non-specific immune responses are reversed by hypoxia stress in immune-challenged fish. Copyright © 2016 Elsevier Inc. All rights reserved.

Fatty Acid β-Oxidation Is Essential in Leptin-Mediated Oocytes Maturation of Yellow Catfish Pelteobagrus fulvidraco.

PubMed

Song, Yu-Feng; Tan, Xiao-Ying; Pan, Ya-Xiong; Zhang, Li-Han; Chen, Qi-Liang

2018-05-14

Although several studies have been conducted to study leptin function, information is very scarce on the molecular mechanism of leptin in fatty acid β-oxidation and oocytes maturation in fish. In this study, we investigated the potential role of fatty acid β-oxidation in leptin-mediated oocytes maturation in Pelteobagrus fulvidraco . Exp. 1 investigated the transcriptomic profiles of ovary and the differential expression of genes involved in β-oxidation and oocytes maturation following rt-hLEP injection; rt-hLEP injection was associated with significant changes in the expression of genes, including twenty-five up-regulated genes ( CPT1 , Acsl , Acadl , Acadm , Hadhb , Echsl , Hsd17b4 , Acca , PPARα , CYP8B1 , ACOX1 , ACBP , MAPK , RINGO , Cdc2 , MEK1 , IGF-1R , APC/C, Cdk2 , GnRHR, STAG3 , SMC1 , FSHβ and C-Myc ) and ten down-regulated gene ( PPARγ , FATCD36 , UBC , PDK1 , Acads , Raf , Fizzy , C3H-4 , Raf and PKC ), involved in fatty acid β-oxidation and oocytes maturation. In Exp. 2, rt-hLEP and specific inhibitors AG490 (JAK-STAT inhibitor) were used to explore whether leptin induced oocytes maturation, and found that leptin incubation increased the diameters of oocytes and percentage of germinal vesicle breakdown (GVBD)-MII oocytes, up-regulated mRNA levels of genes involved in oocytes maturation and that leptin-induced oocyte maturation was related to activation of JAK-STAT pathway. In Exp. 3, primary oocytes of P. fulvidraco were treated with (R)-(+)-etomoxir (an inhibitor of β-oxidation) or l-carnitine (an enhancer of β-oxidation) for 48 h under rt-hLEP incubation. Exp. 3 indicated that the inhibition of fatty acid β-oxidation resulted in the down-regulation of gene expression involved in oocytes maturation, and repressed the leptin-induced up-regulation of these gene expression. Activation of fatty acid β-oxidation improved the maturation rate and mean diameter of oocytes, and up-regulated gene expression involved in oocytes maturation. Leptin is one of the main factors that links fatty acid β-oxidation with oocyte maturation; β-oxidation is essential for leptin-mediated oocyte maturation in fish.

Growth hormone transgenesis in coho salmon disrupts muscle immune function impacting cross-talk with growth systems.

PubMed

Alzaid, Abdullah; Kim, Jin-Hyoung; Devlin, Robert H; Martin, Samuel A M; Macqueen, Daniel J

2018-04-26

Suppression of growth during infection may aid resource allocation towards effective immune function. Past work supporting this hypothesis in salmonid fish revealed an immune-responsive regulation of the insulin-like growth factor (IGF) system, an endocrine pathway downstream of growth hormone (GH). Skeletal muscle is the main target for growth and energetic storage in fish, yet little is known about how its growth is regulated during an immune response. We addressed this knowledge gap by characterizing muscle immune responses in size-matched coho salmon ( Oncorhynchus kisutch ) achieving different growth rates. We compared a wild-type strain with two GH transgenic groups from the same genetic background achieving either maximal or suppressed growth, a design separating GH's direct effects from its influence on growth rate and nutritional state. Fish were sampled 30h post-injection with PBS (control) or mimics of bacterial or viral infection. We quantified mRNA expression levels for genes from the GH, GH receptor, IGF hormone, IGF1 receptor and IGF-binding protein families, along with immune genes involved in inflammatory or antiviral responses and muscle growth status marker genes. We demonstrate dampened immune function in GH transgenics compared to wild-type. The muscle of GH transgenics achieving rapid growth showed no detectable antiviral response, coupled with evidence of a constitutive inflammatory state. GH and IGF system gene expression was strongly altered by GH transgenesis and fast growth, both for baseline expression and responses to immune stimulation. Thus, GH transgenesis strongly disrupts muscle immune status and normal GH and IGF system expression responses to immune stimulation. © 2018. Published by The Company of Biologists Ltd.

Host responses of Japanese flounder Paralichthys olivaceus with lymphocystis cell formation.

PubMed

Iwakiri, Shogo; Song, Jun-Young; Nakayama, Kei; Oh, Myung-Joo; Ishida, Minoru; Kitamura, Shin-Ichi

2014-06-01

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease (LCD). In this study, we investigated the mechanisms of lymphocystis cell (LCC) formation from the viewpoint of gene expression changes in the infected fish. LCC occurrence and virus titers in the experimentally infected Japanese flounder, Paralichthys olivaceus were monitored by visual confirmation and real-time PCR, respectively. The gene expression changes in the fish fin were investigated by microarray experiments. LCCs firstly appeared in the fish at 21 days post infection (dpi). LCD incidence increased with time and reached 92.9% at 62 dpi. LCDV genome was firstly detected from dorsal fins at 14 dpi, and the relative amount of the genome gradually-increased until 56 dpi. Since the occurrence of LCC was approximately synchronized with increasing of the virus genome, virus replication might play important roles for LCC formation. The microarray detected a few gene expression changes until 28 dpi. However, the number of expression changed genes dramatically increased between 28 and 42 dpi in which LCCs formation was active. From the microarray data analyses, apoptosis and cell division related genes were down-regulated, whereas cell fusion and collagen related genes were up-regulated at 42 dpi. Together with the observation of morphological changes of LCCs in previous reports, it is suggested that the following steps are involved in LCC formation: the virus infected cells were (1) inhibited apoptotic death and (2) cell division before enlargement, (3) hypertrophied by cell fusion, and (4) surrounded by a hyaline capsule associated with the alteration of collagen fibers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Identification and characterisation of TLR18-21 genes in Atlantic salmon (Salmo salar).

PubMed

Lee, P T; Zou, J; Holland, J W; Martin, S A M; Collet, B; Kanellos, T; Secombes, C J

2014-12-01

Teleost fish possess many types of toll-like receptor (TLR) some of which exist in other vertebrate groups and some that do not (ie so-called "fish-specific" TLRs). In this study, we identified in Atlantic salmon (Salmo salar) whole-genome shotgun (WGS) contigs seven TLRs that are not found in mammals, including six types of fish-specific TLRs (one TLR18, one TLR19, and four TLR20 members (two of which are putative soluble forms (s)) and one TLR21. Phylogenetic analysis revealed that teleost TLR19-21 are closely related with murine TLR11-TLR13, whilst teleost TLR18 groups with mammalian TLR1, 2, 6 and 10. A typical TLR protein domain structure was found in all these TLRs with the exception of TLR20b(s) and TLR20c(s). TLR-GFP expression plasmids transfected into SHK-1 cells showed that salmon TLR19, TLR20a and TLR20d were preferentially localised to the intracellular compartment. Real time PCR analysis suggested that salmon TLR19-TLR21 are mainly expressed in immune related organs, such as spleen, head kidney and gills, while TLR18 transcripts are more abundant in muscle. In vitro stimulation of primary head kidney cells with type I IFN, IFNγ and IL-1β had no impact on TLR expression. Infectious salmon anaemia virus (ISAV) infection, in vivo, down-regulated TLR20a, TLR20b(s), TLR20d and TLR21 in infected salmon kidney tissue. In contrast, up-regulation of TLR19 and TLR20a expression was found in posterior kidney in rainbow trout with clinical proliferative kidney disease (PKD). Copyright © 2014 Elsevier Ltd. All rights reserved.

Green tea (Camellia sinensis) administration induces expression of immune relevant genes and biochemical parameters in rainbow trout (Oncorhynchus mykiss).

PubMed

Nootash, Shahab; Sheikhzadeh, Najmeh; Baradaran, Behzad; Oushani, Ali Khani; Maleki Moghadam, Mohammad Reza; Nofouzi, Katayoon; Monfaredan, Amir; Aghebati, Leili; Zare, Fatemeh; Shabanzadeh, Sadigheh

2013-12-01

Present study elucidates the efficacy of green tea (Camellia sinensis) on growth performance, immune and antioxidant systems and cytokine gene expression in rainbow trout tissues. Green tea was supplemented at 20, 100, and 500 mg kg(-1) diet and fed to fish (average weight: 23.5 g) for 35 days. No remarkable changes in growth performance were observed among all test groups. Lower lipid peroxidation product and higher superoxide dismutase activity were noted in fish received the medium dose of green tea. Significant increase in serum bactericidal activity and total protein were recorded in all treatment groups. All doses of green tea up-regulated Interleukin-1β transcription in the spleen, while Interleukin-1β mRNA level decreased significantly in the kidney of low dose of green tea. Interleukin-6 mRNA level was up-regulated in the spleen of high dose of green tea and liver of middle and high doses of green tea. High dose and medium dose of green tea up-regulated the interleukin-8 transcription in the kidney and liver, respectively. Meanwhile, green tea inhibited the production of interleukin-10 in all treatment groups compared with control group. Medium dose of green tea up-regulated tumor necrosis factor-α transcription in all fish tissues, while high dose and low dose of green tea enhanced tumor necrosis factor-α mRNA levels in the kidney and spleen, respectively. Present study suggests that green tea especially at 100 mg kg(-1) feed may effectively enhance the antioxidant system and immune system in rainbow trout. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cloning and expression characterization of peroxisome proliferator-activated receptors (PPARs) with their agonists, dietary lipids, and ambient salinity in rabbitfish Siganus canaliculatus.

PubMed

You, Cuihong; Jiang, Danli; Zhang, Qinghao; Xie, Dizhi; Wang, Shuqi; Dong, Yewei; Li, Yuanyou

2017-04-01

Rabbitfish Siganus canaliculatus is the first marine teleost reported to have the ability of biosynthesizing C 20-22 long-chain polyunsaturated fatty acids (LC-PUFA) from C 18 precursors, and thus provides a model for studying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. To investigate the possible roles of peroxisome proliferator-activated receptors (PPARs), critical transcription factors involved in the regulation of lipid metabolism, in the regulation of LC-PUFA biosynthesis in rabbitfish, the PPAR genes were cloned and their expression characterization with PPAR agonists, dietary lipid resource, and ambient salinity were examined. Three cDNA sequences respectively encoding 477, 516 and 519 amino acids of PPARα, PPARβ, and PPARγ isoforms were obtained. PPARα exhibited a wide tissue expression with its highest levels in the heart and brain; PPARβ was predominantly expressed in the gills, while PPARγ was highly expressed in the intestine and gills. In rabbitfish primary hepatocytes, both the PPAR agonists 2-bromopalmitate (2-Bro) and fenofibrate (FF) increased the expression of PPARγ, SREBP1c and Elovl5, whereas FF depressed the expression of Δ6/Δ5 Fad. Moreover, a higher hepatic PPARβ expression was observed in fish fed diets with vegetable oils (VO) than that with fish oil (FO), in the former the expression of PPARα, PPARβ, and PPARγ were increased at the low ambient salinity (10ppt), where an increasing expression of Δ5/Δ6 Fad, Δ4 Fad and Elovl5 genes was previously reported. These results suggest that PPARs might be involved in the upregulation of LC-PUFA biosynthesis with dietary VO and low ambient salinity in rabbitfish. Copyright © 2017 Elsevier Inc. All rights reserved.

MicroRNA signature in response to nutrient restriction and re-feeding in fast skeletal muscle of grass carp (Ctenopharyngodon idella).

PubMed

Zhu, Xin; Chu, Wu-Ying; Wu, Ping; Yi, Tan; Chen, Tao; Zhang, Jian-She

2014-09-01

The grass carp (Ctenopharyngodon idella) is one of the most important cultivated fish species in China. Mounting evidences suggests that microRNAs (miRNAs) may be key regulators of skeletal muscle among the grass carp, but the knowledge of the identity of myogenic miRNAs and role of miRNAs during skeletal muscle anabolic state remains limited. In the present study, we choose 8 miRNAs previously reported to act as muscle growth-related miRNAs for fasting-refeeding research. We investigated postprandial changes in the expression of 8 miRNAs following a single satiating meal in grass carp juveniles who had been fasting for one week and found that 7 miRNAs were sharply up-regulated within 1 or 3 h after refeeding, suggesting that they may be promising candidate miRNAs involved in a fast-response signaling system that regulates fish skeletal muscle growth.

Alpinone exhibited immunomodulatory and antiviral activities in Atlantic salmon.

PubMed

Valenzuela, Beatriz; Rodríguez, Felipe E; Modak, Brenda; Imarai, Mónica

2018-03-01

In this study, we seek to identify flavonoids able to regulate the gene expression of a group of cytokines important for the control of infections in Atlantic salmon (Salmo salar). Particularly, we studied the potential immunomodulatory effects of two flavonoids, Alpinone and Pinocembrine, which were isolated and purified from resinous exudates of Heliotropium huascoense and Heliotropium sinuatum, respectively. The transcript levels of TNF-α and IL-1 (inflammatory cytokines), IFN-γ and IL-12 (T helper 1 type cytokines), IL4/13A (Th2-type cytokine), IL-17 (Th17 type cytokine) TGF-β1 (regulatory cytokine) and IFN-α (antiviral cytokine) were quantified by qRT-PCR in kidneys of flavonoid-treated and control fish. We demonstrated that the administration of a single intramuscular dose of purified Alpinone increased the transcriptional expression of five cytokines, named TNF-α, IL-1, IFN-α, IFN-γ and TGF-β1 in treated fish compared to untreated fish. Conversely, administration of purified Pinocembrine reduced the transcriptional expression of TNF-α, IL-1 and IL-12 in the kidney of treated fish. No other changes were observed. Interestingly, Alpinone also induced in vitro antiviral effects against Infectious Salmon Anaemia virus. Results showed that Alpinone but not Pinocembrine induces the expression of cytokines, which in vertebrates are essential to control viral infections while Pinocembrine reduces pro-inflammatory cytokines. Altogether results suggest that Alpinone is a good candidate to be further tested as immunostimulant and antiviral drug. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pre and postprandial changes in orexigenic and anorexigenic factors in channel catfish Ictalurus punctatus

USDA-ARS?s Scientific Manuscript database

We examined pre- and postprandial changes in the expression of plasma ghrelin (GHRL) and mRNAs encoding GRLN, cocaine and amphetamine regulated transcript (CART), neuropeptide Y (NPY), and cholecystokinin (CCK) in channel catfish. Fish were either offered feed (Fed) or fasted (Unfed). Feeding incr...

Nutrient transporter gene expression in poultry, livestock and fish

USDA-ARS?s Scientific Manuscript database

The absorption of nutrients such as amino acids, peptides, monosaccharides and minerals by cells and tissues is mediated by a series of membrane bound transporters that are members of the solute carrier (SLC) gene family. These transporters regulate the influx and efflux of nutrients in a wide vari...

Functional genomics reveals increases in cholesterol biosynthetic genes and highly unsaturated fatty acid biosynthesis after dietary substitution of fish oil with vegetable oils in Atlantic salmon (Salmo salar)

PubMed Central

Leaver, Michael J; Villeneuve, Laure AN; Obach, Alex; Jensen, Linda; Bron, James E; Tocher, Douglas R; Taggart, John B

2008-01-01

Background There is an increasing drive to replace fish oil (FO) in finfish aquaculture diets with vegetable oils (VO), driven by the short supply of FO derived from wild fish stocks. However, little is known of the consequences for fish health after such substitution. The effect of dietary VO on hepatic gene expression, lipid composition and growth was determined in Atlantic salmon (Salmo salar), using a combination of cDNA microarray, lipid, and biochemical analysis. FO was replaced with VO, added to diets as rapeseed (RO), soybean (SO) or linseed (LO) oils. Results Dietary VO had no major effect on growth of the fish, but increased the whole fish protein contents and tended to decrease whole fish lipid content, thus increasing the protein:lipid ratio. Expression levels of genes of the highly unsaturated fatty acid (HUFA) and cholesterol biosynthetic pathways were increased in all vegetable oil diets as was SREBP2, a master transcriptional regulator of these pathways. Other genes whose expression was increased by feeding VO included those of NADPH generation, lipid transport, peroxisomal fatty acid oxidation, a marker of intracellular lipid accumulation, and protein and RNA processing. Consistent with these results, HUFA biosynthesis, hepatic β-oxidation activity and enzymic NADPH production were changed by VO, and there was a trend for increased hepatic lipid in LO and SO diets. Tissue cholesterol levels in VO fed fish were the same as animals fed FO, whereas fatty acid composition of the tissues largely reflected those of the diets and was marked by enrichment of 18 carbon fatty acids and reductions in 20 and 22 carbon HUFA. Conclusion This combined gene expression, compositional and metabolic study demonstrates that major lipid metabolic effects occur after replacing FO with VO in salmon diets. These effects are most likely mediated by SREBP2, which responds to reductions in dietary cholesterol. These changes are sufficient to maintain whole body cholesterol levels but not HUFA levels. PMID:18577222

Developmental Regulation of Gonadotropin-releasing Hormone Gene Expression by the MSX and DLX Homeodomain Protein Families*

PubMed Central

Givens, Marjory L.; Rave-Harel, Naama; Goonewardena, Vinodha D.; Kurotani, Reiko; Berdy, Sara E.; Swan, Christo H.; Rubenstein, John L. R.; Robert, Benoit; Mellon, Pamela L.

2010-01-01

Gonadotropin-releasing hormone (GnRH) is the central regulator of the hypothalamic-pituitary-gonadal axis, controlling sexual maturation and fertility in diverse species from fish to humans. GnRH gene expression is limited to a discrete population of neurons that migrate through the nasal region into the hypothalamus during embryonic development. The GnRH regulatory region contains four conserved homeodomain binding sites (ATTA) that are essential for basal promoter activity and cell-specific expression of the GnRH gene. MSX and DLX are members of the Antennapedia class of non-Hox homeodomain transcription factors that regulate gene expression and influence development of the craniofacial structures and anterior forebrain. Here, we report that expression patterns of the Msx and Dlx families of homeodomain transcription factors largely coincide with the migratory route of GnRH neurons and co-express with GnRH in neurons during embryonic development. In addition, MSX and DLX family members bind directly to the ATTA consensus sequences and regulate transcriptional activity of the GnRH promoter. Finally, mice lacking MSX1 or DLX1 and 2 show altered numbers of GnRH-expressing cells in regions where these factors likely function. These findings strongly support a role for MSX and DLX in contributing to spatiotemporal regulation of GnRH transcription during development. PMID:15743757

32 CFR 770.3 - Fishing regulations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Fishing regulations. 770.3 Section 770.3..., Virginia § 770.3 Fishing regulations. (a) All persons possessing the proper state license and Base permit are permitted to fish in the areas designated by the Annual Fishing Regulations on Marine Corps Base...

32 CFR 770.3 - Fishing regulations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Fishing regulations. 770.3 Section 770.3..., Virginia § 770.3 Fishing regulations. (a) All persons possessing the proper state license and Base permit are permitted to fish in the areas designated by the Annual Fishing Regulations on Marine Corps Base...

Whole Body Melanoma Transcriptome Response in Medaka

PubMed Central

Schartl, Manfred; Shen, Yingjia; Maurus, Katja; Walter, Ron; Tomlinson, Chad; Wilson, Richard K.; Postlethwait, John; Warren, Wesley C.

2015-01-01

The incidence of malignant melanoma continues to increase each year with poor prognosis for survival in many relapse cases. To reverse this trend, whole body response measures are needed to discover collaborative paths to primary and secondary malignancy. Several species of fish provide excellent melanoma models because fish and human melanocytes both appear in the epidermis, and fish and human pigment cell tumors share conserved gene expression signatures. For the first time, we have examined the whole body transcriptome response to invasive melanoma as a prelude to using transcriptome profiling to screen for drugs in a medaka (Oryzias latipes) model. We generated RNA-seq data from whole body RNA isolates for controls and melanoma fish. After testing for differential expression, 396 genes had significantly different expression (adjusted p-value <0.02) in the whole body transcriptome between melanoma and control fish; 379 of these genes were matched to human orthologs with 233 having annotated human gene symbols and 14 matched genes that contain putative deleterious variants in human melanoma at varying levels of recurrence. A detailed canonical pathway evaluation for significant enrichment showed the top scoring pathway to be antigen presentation but also included the expected melanocyte development and pigmentation signaling pathway. Results revealed a profound down-regulation of genes involved in the immune response, especially the innate immune system. We hypothesize that the developing melanoma actively suppresses the immune system responses of the body in reacting to the invasive malignancy, and that this mal-adaptive response contributes to disease progression, a result that suggests our whole-body transcriptomic approach merits further use. In these findings, we also observed novel genes not yet identified in human melanoma expression studies and uncovered known and new candidate drug targets for further testing in this malignant melanoma medaka model. PMID:26714172

Whole Body Melanoma Transcriptome Response in Medaka.

PubMed

Schartl, Manfred; Shen, Yingjia; Maurus, Katja; Walter, Ron; Tomlinson, Chad; Wilson, Richard K; Postlethwait, John; Warren, Wesley C

2015-01-01

The incidence of malignant melanoma continues to increase each year with poor prognosis for survival in many relapse cases. To reverse this trend, whole body response measures are needed to discover collaborative paths to primary and secondary malignancy. Several species of fish provide excellent melanoma models because fish and human melanocytes both appear in the epidermis, and fish and human pigment cell tumors share conserved gene expression signatures. For the first time, we have examined the whole body transcriptome response to invasive melanoma as a prelude to using transcriptome profiling to screen for drugs in a medaka (Oryzias latipes) model. We generated RNA-seq data from whole body RNA isolates for controls and melanoma fish. After testing for differential expression, 396 genes had significantly different expression (adjusted p-value <0.02) in the whole body transcriptome between melanoma and control fish; 379 of these genes were matched to human orthologs with 233 having annotated human gene symbols and 14 matched genes that contain putative deleterious variants in human melanoma at varying levels of recurrence. A detailed canonical pathway evaluation for significant enrichment showed the top scoring pathway to be antigen presentation but also included the expected melanocyte development and pigmentation signaling pathway. Results revealed a profound down-regulation of genes involved in the immune response, especially the innate immune system. We hypothesize that the developing melanoma actively suppresses the immune system responses of the body in reacting to the invasive malignancy, and that this mal-adaptive response contributes to disease progression, a result that suggests our whole-body transcriptomic approach merits further use. In these findings, we also observed novel genes not yet identified in human melanoma expression studies and uncovered known and new candidate drug targets for further testing in this malignant melanoma medaka model.

Control of leptin by metabolic state and its regulatory interactions with pituitary growth hormone and hepatic growth hormone receptors and insulin like growth factors in the tilapia (Oreochromis mossambicus).

PubMed

Douros, Jonathan D; Baltzegar, David A; Mankiewicz, Jamie; Taylor, Jordan; Yamaguchi, Yoko; Lerner, Darren T; Seale, Andre P; Grau, E Gordon; Breves, Jason P; Borski, Russell J

2017-01-01

Leptin is an important cytokine for regulating energy homeostasis, however, relatively little is known about its function and control in teleost fishes or other ectotherms, particularly with regard to interactions with the growth hormone (GH)/insulin-like growth factors (IGFs) growth regulatory axis. Here we assessed the regulation of LepA, the dominant paralog in tilapia (Oreochromis mossambicus) and other teleosts under altered nutritional state, and evaluated how LepA might alter pituitary growth hormone (GH) and hepatic insulin-like growth factors (IGFs) that are known to be disparately regulated by metabolic state. Circulating LepA, and lepa and lepr gene expression increased after 3-weeks fasting and declined to control levels 10days following refeeding. This pattern of leptin regulation by metabolic state is similar to that previously observed for pituitary GH and opposite that of hepatic GHR and/or IGF dynamics in tilapia and other fishes. We therefore evaluated if LepA might differentially regulate pituitary GH, and hepatic GH receptors (GHRs) and IGFs. Recombinant tilapia LepA (rtLepA) increased hepatic gene expression of igf-1, igf-2, ghr-1, and ghr-2 from isolated hepatocytes following 24h incubation. Intraperitoneal rtLepA injection, on the other hand, stimulated hepatic igf-1, but had little effect on hepatic igf-2, ghr1, or ghr2 mRNA abundance. LepA suppressed GH accumulation and gh mRNA in pituitaries in vitro, but had no effect on GH release. We next sought to test if abolition of pituitary GH via hypophysectomy (Hx) affects the expression of hepatic lepa and lepr. Hypophysectomy significantly increases hepatic lepa mRNA abundance, while GH replacement in Hx fish restores lepa mRNA levels to that of sham controls. Leptin receptor (lepr) mRNA was unchanged by Hx. In in vitro hepatocyte incubations, GH inhibits lepa and lepr mRNA expression at low concentrations, while higher concentration stimulates lepa expression. Taken together, these findings indicate LepA gene expression and secretion increases with fasting, consistent with the hormones function in promoting energy expenditure during catabolic stress. It would also appear that LepA might play an important role in stimulating GHR and IGFs to potentially spare declines in these factors during catabolism. Evidence also suggests for the first time in teleosts that GH may exert important regulatory effects on hepatic LepA production, insofar as physiological levels (0.05-1 nM) suppresse lepa mRNA accumulation. Leptin A, may in turn exert negative feedback effects on basal GH mRNA abundance, but not secretion. Copyright © 2016 Elsevier Inc. All rights reserved.

The Transcription Factor Atonal homolog 8 Regulates Gata4 and Friend of Gata-2 during Vertebrate Development

PubMed Central

Rawnsley, David R.; Xiao, Jiping; Lee, John S.; Liu, Xi; Mericko-Ishizuka, Patricia; Kumar, Vinayak; He, Jie; Basu, Arindam; Lu, MinMin; Lynn, Francis C.; Pack, Michael; Gasa, Rosa; Kahn, Mark L.

2013-01-01

GATA and Friend of GATA (FOG) form a transcriptional complex that plays a key role in cardiovascular development in both fish and mammals. In the present study we demonstrate that the basic helix-loop-helix transcription factor Atonal homolog 8 (Atoh8) is required for development of the heart in fish but not in mice. Genetic studies reveal that Atoh8 interacts specifically with Gata4 and Fog1 during development of the heart and swim bladder in the fish. Biochemical studies reveal that ATOH8, GATA4, and FOG2 associate in a single complex in vitro. In contrast to fish, ATOH8-deficient mice exhibit normal cardiac development and loss of ATOH8 does not alter cardiac development in Gata4+/− mice. This species difference in the role of ATOH8 is explained in part by LacZ and GFP reporter alleles that reveal restriction of Atoh8 expression to atrial but not ventricular myocardium in the mouse. Our findings identify ATOH8 as a novel regulator of GATA-FOG function that is required for cardiac development in the fish but not the mouse. Whether ATOH8 modulates GATA-FOG function at other sites or in more subtle ways in mammals is not yet known. PMID:23836893

Live-cell imaging combined with immunofluorescence, RNA, or DNA FISH to study the nuclear dynamics and expression of the X-inactivation center.

PubMed

Pollex, Tim; Piolot, Tristan; Heard, Edith

2013-01-01

Differentiation of embryonic stem cells is accompanied by changes of gene expression and chromatin and chromosome dynamics. One of the most impressive examples for these changes is inactivation of one of the two X chromosomes occurring upon differentiation of mouse female embryonic stem cells. With a few exceptions, these events have been mainly studied in fixed cells. In order to better understand the dynamics, kinetics, and order of events during differentiation, one needs to employ live-cell imaging techniques. Here, we describe a combination of live-cell imaging with techniques that can be used in fixed cells (e.g., RNA FISH) to correlate locus dynamics or subnuclear localization with, e.g., gene expression. To study locus dynamics in female ES cells, we generated cell lines containing TetO arrays in the X-inactivation center, the locus on the X chromosome regulating X-inactivation, which can be visualized upon expression of TetR fused to fluorescent proteins. We will use this system to elaborate on how to generate ES cell lines for live-cell imaging of locus dynamics, how to culture ES cells prior to live-cell imaging, and to describe typical live-cell imaging conditions for ES cells using different microscopes. Furthermore, we will explain how RNA, DNA FISH, or immunofluorescence can be applied following live-cell imaging to correlate gene expression with locus dynamics.

50 CFR 300.189 - Prohibitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Customs territory of the United States of fish or fish products regulated under this subpart except shark... accept an imported consignment of fish or fish products regulated under this subpart, except shark fins...-export any fish or fish product regulated under this subpart without a valid trade permit issued under...

50 CFR 300.189 - Prohibitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Customs territory of the United States of fish or fish products regulated under this subpart except shark... accept an imported consignment of fish or fish products regulated under this subpart, except shark fins...-export any fish or fish product regulated under this subpart without a valid trade permit issued under...

Defining global neuroendocrine gene expression patterns associated with reproductive seasonality in fish.

PubMed

Zhang, Dapeng; Xiong, Huiling; Mennigen, Jan A; Popesku, Jason T; Marlatt, Vicki L; Martyniuk, Christopher J; Crump, Kate; Cossins, Andrew R; Xia, Xuhua; Trudeau, Vance L

2009-06-05

Many vertebrates, including the goldfish, exhibit seasonal reproductive rhythms, which are a result of interactions between external environmental stimuli and internal endocrine systems in the hypothalamo-pituitary-gonadal axis. While it is long believed that differential expression of neuroendocrine genes contributes to establishing seasonal reproductive rhythms, no systems-level investigation has yet been conducted. In the present study, by analyzing multiple female goldfish brain microarray datasets, we have characterized global gene expression patterns for a seasonal cycle. A core set of genes (873 genes) in the hypothalamus were identified to be differentially expressed between May, August and December, which correspond to physiologically distinct stages that are sexually mature (prespawning), sexual regression, and early gonadal redevelopment, respectively. Expression changes of these genes are also shared by another brain region, the telencephalon, as revealed by multivariate analysis. More importantly, by examining one dataset obtained from fish in October who were kept under long-daylength photoperiod (16 h) typical of the springtime breeding season (May), we observed that the expression of identified genes appears regulated by photoperiod, a major factor controlling vertebrate reproductive cyclicity. Gene ontology analysis revealed that hormone genes and genes functionally involved in G-protein coupled receptor signaling pathway and transmission of nerve impulses are significantly enriched in an expression pattern, whose transition is located between prespawning and sexually regressed stages. The existence of seasonal expression patterns was verified for several genes including isotocin, ependymin II, GABA(A) gamma2 receptor, calmodulin, and aromatase b by independent samplings of goldfish brains from six seasonal time points and real-time PCR assays. Using both theoretical and experimental strategies, we report for the first time global gene expression patterns throughout a breeding season which may account for dynamic neuroendocrine regulation of seasonal reproductive development.

Defining Global Neuroendocrine Gene Expression Patterns Associated with Reproductive Seasonality in Fish

PubMed Central

Mennigen, Jan A.; Popesku, Jason T.; Marlatt, Vicki L.; Martyniuk, Christopher J.; Crump, Kate; Cossins, Andrew R.; Xia, Xuhua; Trudeau, Vance L.

2009-01-01

Background Many vertebrates, including the goldfish, exhibit seasonal reproductive rhythms, which are a result of interactions between external environmental stimuli and internal endocrine systems in the hypothalamo-pituitary-gonadal axis. While it is long believed that differential expression of neuroendocrine genes contributes to establishing seasonal reproductive rhythms, no systems-level investigation has yet been conducted. Methodology/Principal Findings In the present study, by analyzing multiple female goldfish brain microarray datasets, we have characterized global gene expression patterns for a seasonal cycle. A core set of genes (873 genes) in the hypothalamus were identified to be differentially expressed between May, August and December, which correspond to physiologically distinct stages that are sexually mature (prespawning), sexual regression, and early gonadal redevelopment, respectively. Expression changes of these genes are also shared by another brain region, the telencephalon, as revealed by multivariate analysis. More importantly, by examining one dataset obtained from fish in October who were kept under long-daylength photoperiod (16 h) typical of the springtime breeding season (May), we observed that the expression of identified genes appears regulated by photoperiod, a major factor controlling vertebrate reproductive cyclicity. Gene ontology analysis revealed that hormone genes and genes functionally involved in G-protein coupled receptor signaling pathway and transmission of nerve impulses are significantly enriched in an expression pattern, whose transition is located between prespawning and sexually regressed stages. The existence of seasonal expression patterns was verified for several genes including isotocin, ependymin II, GABAA gamma2 receptor, calmodulin, and aromatase b by independent samplings of goldfish brains from six seasonal time points and real-time PCR assays. Conclusions/Significance Using both theoretical and experimental strategies, we report for the first time global gene expression patterns throughout a breeding season which may account for dynamic neuroendocrine regulation of seasonal reproductive development. PMID:19503831

Temporal variation in brain transcriptome is associated with the expression of female mimicry as a sequential male alternative reproductive tactic in fish.

PubMed

Cardoso, Sara D; Gonçalves, David; Goesmann, Alexander; Canário, Adelino V M; Oliveira, Rui F

2018-02-01

Distinct patterns of gene expression often underlie intra- and intersexual differences, and the study of this set of coregulated genes is essential to understand the emergence of complex behavioural phenotypes. Here, we describe the development of a de novo transcriptome and brain gene expression profiles of wild-caught peacock blenny, Salaria pavo, an intertidal fish with sex-role reversal in courtship behaviour (i.e., females are the courting sex) and sequential alternative reproductive tactics in males (i.e., larger and older nest-holder males and smaller and younger sneaker males occur). Sneakers mimic both female's courtship behaviour and nuptial coloration to get access to nests and sneak fertilizations, and later in life transition into nest-holder males. Thus, this species offers the unique opportunity to study how the regulation of gene expression can contribute to intersex phenotypes and to the sequential expression of male and female behavioural phenotypes by the same individual. We found that at the whole brain level, expression of the sneaker tactic was paralleled by broader and divergent gene expression when compared to either females or nest-holder males, which were more similar between themselves. When looking at sex-biased transcripts, sneaker males are intersex rather than being either nest-holder or female-like, and their transcriptome is simultaneously demasculinized for nest-holder-biased transcripts and feminized for female-biased transcripts. These results indicate that evolutionary changes in reproductive plasticity can be achieved through regulation of gene expression, and in particular by varying the magnitude of expression of sex-biased genes, throughout the lifetime of the same individual. © 2017 John Wiley & Sons Ltd.

First in-depth analysis of the novel Th2-type cytokines in salmonid fish reveals distinct patterns of expression and modulation but overlapping bioactivities

PubMed Central

Wang, Tiehui; Johansson, Petronella; Abós, Beatriz; Holt, Amy; Tafalla, Carolina; Jiang, Youshen; Wang, Alex; Xu, Qiaoqing; Qi, Zhitao; Huang, Wenshu; Costa, Maria M.; Diaz-Rosales, Patricia; Holland, Jason W.; Secombes, Christopher J.

2016-01-01

IL-4 and IL-13 are closely related canonical type-2 cytokines in mammals and have overlapping bioactivities via shared receptors. They are frequently activated together as part of the same immune response and are the signature cytokines produced by T-helper (Th)2 cells and type-2 innate lymphoid cells (ILC2), mediating immunity against extracellular pathogens. Little is known about the origin of type-2 responses, and whether they were an essential component of the early adaptive immune system that gave a fitness advantage by limiting collateral damage caused by metazoan parasites. Two evolutionary related type-2 cytokines, IL-4/13A and IL-4/13B, have been identified recently in several teleost fish that likely arose by duplication of an ancestral IL-4/13 gene as a consequence of a whole genome duplication event that occurred at the base of this lineage. However, studies of their comparative expression levels are largely missing and bioactivity analysis has been limited to IL-4/13A in zebrafish. Through interrogation of the recently released salmonid genomes, species in which an additional whole genome duplication event has occurred, four genomic IL-4/13 loci have been identified leading to the cloning of three active genes, IL-4/13A, IL-4/13B1 and IL-4/13B2, in both rainbow trout and Atlantic salmon. Comparative expression analysis by real-time PCR in rainbow trout revealed that the IL-4/13A expression is broad and high constitutively but less responsive to pathogen-associated molecular patterns (PAMPs) and pathogen challenge. In contrast, the expression of IL-4/13B1 and IL-4/13B2 is low constitutively but is highly induced by viral haemorrhagic septicaemia virus (VHSH) infection and during proliferative kidney disease (PKD) in vivo, and by formalin-killed bacteria, PAMPs, the T cell mitogen PHA, and the T-cell cytokines IL-2 and IL-21 in vitro. Moreover, bioactive recombinant cytokines of both IL-4/13A and B were produced and found to have shared but also distinct bioactivities. Both cytokines rapidly induce the gene expression of antimicrobial peptides and acute phase proteins, providing an effector mechanism of fish type-2 cytokines in immunity. They are anti-inflammatory via up-regulation of IL-10 and down-regulation of IL-1β and IFN-γ. They modulate the expression of cellular markers of T cells, macrophages and B cells, the receptors of IFN-γ, the IL-6 cytokine family and their own potential receptors, suggesting multiple target cells and important roles of fish type-2 cytokines in the piscine cytokine network. Furthermore both cytokines increased the number of IgM secreting B cells but had no effects on the proliferation of IgM+ B cells in vitro. Taken as a whole, fish IL-4/13A may provide a basal level of type-2 immunity whilst IL-4/13B, when activated, provides an enhanced type-2 immunity, which may have an important role in specific cell-mediated immunity. To our knowledge this is the first in-depth analysis of the expression, modulation and bioactivities of type-2 cytokines in the same fish species, and in any early vertebrate. It contributes to a broader understanding of the evolution of type-2 immunity in vertebrates, and establishes a framework for further studies and manipulation of type-2 cytokines in fish. PMID:26870894

The Neuroendocrine Regulation of Food Intake in Fish: A Review of Current Knowledge

PubMed Central

Volkoff, Helene

2016-01-01

Fish are the most diversified group of vertebrates and, although progress has been made in the past years, only relatively few fish species have been examined to date, with regards to the endocrine regulation of feeding in fish. In fish, as in mammals, feeding behavior is ultimately regulated by central effectors within feeding centers of the brain, which receive and process information from endocrine signals from both brain and peripheral tissues. Although basic endocrine mechanisms regulating feeding appear to be conserved among vertebrates, major physiological differences between fish and mammals and the diversity of fish, in particular in regard to feeding habits, digestive tract anatomy and physiology, suggest the existence of fish- and species-specific regulating mechanisms. This review provides an overview of hormones known to regulate food intake in fish, emphasizing on major hormones and the main fish groups studied to date. PMID:27965528

The effects of exogenous cortisol on myostatin transcription in rainbow trout, Oncorhynchus mykiss

PubMed Central

Galt, Nicholas J.; Froehlich, Jacob Michael; Remily, Ethan A.; Romero, Sinibaldo R.; Biga, Peggy R.

2014-01-01

Glucocorticoids (GCs) strongly regulate myostatin transcript levels in mammals via glucocorticoid response elements (GREs) in the myostatin promoter, and bioinformatics methods suggest that this regulatory mechanism is conserved among many vertebrates. However, the multiple myostatin genes found in some fishes may be an exception. In rainbow trout (Oncorhynchus mykiss), two genome duplication events have produced three putatively functional myostatin genes, myostatin-1a, -1b and -2a, which are ubiquitously and differentially expressed. In addition, in silico promoter analyses of the rainbow trout myostatin promoters have failed to identify putative GREs, suggesting a divergence in myostatin function. Therefore, we hypothesized that myostatin mRNA expression is not regulated by glucocorticoids in rainbow trout. In this study, both juvenile rainbow trout and primary trout myoblasts were treated with cortisol to examine the relationship between this glucocorticoid and myostatin mRNA expression. Results suggest that exogenous cortisol does not regulate myostatin-1a and -1b expression in vivo, as myostatin mRNA levels were not significantly affected by cortisol treatment in either red or white muscle tissue. In red muscle, myostatin-2a levels were significantly elevated in the cortisol treatment group relative to the control, but not the vehicle control, at both 12 h and 24 h post-injection. As such, it is unclear if cortisol was acting alone or in combination with the vehicle. Cortisol increased myostatin-1b expression in a dose-dependent manner in vitro. Further work is needed to determine if this response is the direct result of cortisol acting on the myostatin-1b promoter or through an alternative mechanism. These results suggest that regulation of myostatin by cortisol may not be as highly conserved as previously thought and support previous work that describes potential functional divergence of the multiple myostatin genes in fishes. PMID:24875565

miR-1338-5p Modulates Growth Hormone Secretion and Glucose Utilization by Regulating ghitm in Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus)

PubMed Central

Qiang, Jun; Bao, Jing Wen; Li, Hong Xia; Chen, De Ju; He, Jie; Tao, Yi Fan; Xu, Pao

2017-01-01

MicroRNAs (miRNAs) are endogenous, non-coding small RNA molecules about 22 nt in length, which could regulate the expressions of target genes and participate in growth and development of organisms. Genetically improved farmed tilapia (GIFT, Oreochromis niloticus) is an important economic freshwater species in China and the growth performance is one of the main breeding indicators. Growth hormone inducible transmembrane protein (ghitm) plays an important role in growth and development of both mammals and invertebrates; however, little studies have been reported on fish. Our previous experiments indicated that miR-1338-5p expression may be negatively correlated with ghitm expression. In this study, we firstly used qRT-PCR and northern blot to verify the expression of miR-1338-5p and ghitm, and determined the binding site of miR-1338-5p in the ghitm 3′-untranslated region (UTR) by luciferase reporter assay. Secondly, juveniles GIFT injected with miR-1338-5p antagomir were used to analyze the regulatory function of the miR-1338-5p-ghitm pair in vivo. The results showed that the ghitm 3′-UTR was complementary to the 5′ 2–8-nt site of miR-1338-5p. Inhibition of miR-1338-5p promoted ghitm expression in the pituitary and liver of GIFT. ghitm could interfere in the growth hormone (Gh)–growth hormone receptor (Ghr)–insulin-like growth factor (Igf) signaling pathway by competing with the ghr1 for combination with Gh, and then reduce the growth of GIFT. Moreover, the reduction of Gh in serum may regulate insulin secretion and result in the increasing sugar and fat storage in serum and liver. Our results suggest that miR-1338-5p participates in the growth and development of GIFT through the regulation of ghitm, which provides theoretical support for the study of the fish growth mechanism. PMID:29270127

miR-1338-5p Modulates Growth Hormone Secretion and Glucose Utilization by Regulating ghitm in Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus).

PubMed

Qiang, Jun; Bao, Jing Wen; Li, Hong Xia; Chen, De Ju; He, Jie; Tao, Yi Fan; Xu, Pao

2017-01-01

MicroRNAs (miRNAs) are endogenous, non-coding small RNA molecules about 22 nt in length, which could regulate the expressions of target genes and participate in growth and development of organisms. Genetically improved farmed tilapia (GIFT, Oreochromis niloticus ) is an important economic freshwater species in China and the growth performance is one of the main breeding indicators. Growth hormone inducible transmembrane protein ( ghitm ) plays an important role in growth and development of both mammals and invertebrates; however, little studies have been reported on fish. Our previous experiments indicated that miR-1338-5p expression may be negatively correlated with ghitm expression. In this study, we firstly used qRT-PCR and northern blot to verify the expression of miR-1338-5p and ghitm , and determined the binding site of miR-1338-5p in the ghitm 3'-untranslated region (UTR) by luciferase reporter assay. Secondly, juveniles GIFT injected with miR-1338-5p antagomir were used to analyze the regulatory function of the miR-1338-5p- ghitm pair in vivo . The results showed that the ghitm 3'-UTR was complementary to the 5' 2-8-nt site of miR-1338-5p. Inhibition of miR-1338-5p promoted ghitm expression in the pituitary and liver of GIFT. ghitm could interfere in the growth hormone (Gh)-growth hormone receptor (Ghr)-insulin-like growth factor (Igf) signaling pathway by competing with the ghr1 for combination with Gh, and then reduce the growth of GIFT. Moreover, the reduction of Gh in serum may regulate insulin secretion and result in the increasing sugar and fat storage in serum and liver. Our results suggest that miR-1338-5p participates in the growth and development of GIFT through the regulation of ghitm , which provides theoretical support for the study of the fish growth mechanism.

High mortality of juvenile gilthead sea bream (Sparus aurata) from photobacteriosis is associated with alternative macrophage activation and anti-inflammatory response: results of gene expression profiling of early responses in the head kidney.

PubMed

Pellizzari, Caterina; Krasnov, Aleksei; Afanasyev, Sergey; Vitulo, Nicola; Franch, Rafaella; Pegolo, Sara; Patarnello, Tomaso; Bargelloni, Luca

2013-05-01

The halophilic bacterium Photobacterium damselae subsp. piscicida (Phdp) represents a substantial health problem for several fish species in aquaculture. Bacteria that reside free and inside phagocytes cause acute and chronic forms of photobacteriosis. Infections of juveniles rapidly kill up to 90-100% fish. Factors underlying failure of the immune protection against bacteria remain largely unknown. The reported study used a transcriptomic approach to address this issue. Juvenile sea breams (0.5 g) were challenged by immersion in salt water containing 2.89 × 10(8) CFU of a virulent Phdp and the head kidney was sampled after 24- and 48-h. Analyses were performed using the second version of a 44 k oligonucleotide DNA microarray that represents 19,734 sea bream unique transcripts and covers diverse immune pathways. Expression changes of selected immune genes were validated with qPCR. Results suggested rapid recognition of the pathogen, as testified by up-regulation of lectins and antibacterial proteins (bactericidal permeability-increasing protein lectins, lysozyme, intracellular and extracellular proteases), chemokines and chemokine receptors. Increased expression of proteins involved in iron and heme metabolism also could be a response against bacteria that are dependent on iron. However, negative regulators of immune/inflammatory response were preponderant among the up-regulated genes. A remarkable finding was the increased expression of IL-10 in concert with up-regulation of arginase I and II and proteins of the polyamine biosynthesis pathway that diverts the arginine flux from the production of reactive nitrogen species. Such expression changes are characteristic for alternatively activated macrophages that do not develop acute inflammatory responses. Immune suppression can be induced by the host to reduce tissue damages or by the pathogen to evade host response. Copyright © 2013 Elsevier Ltd. All rights reserved.

Expression of Key Ion Transporters in the Gill and Esophageal-Gastrointestinal Tract of Euryhaline Mozambique Tilapia Oreochromis mossambicus Acclimated to Fresh Water, Seawater and Hypersaline Water

PubMed Central

Li, Zhengjun; Lui, Eei Yin; Wilson, Jonathan M.; Ip, Yuen Kwong; Lin, Qingsong; Lam, Toong Jin; Lam, Siew Hong

2014-01-01

The ability of euryhaline Mozambique tilapia to tolerate extreme environmental salinities makes it an excellent model for investigating iono-regulation. This study aimed to characterize and fill important information gap of the expression levels of key ion transporters for Na+ and Cl− in the gill and esophageal-gastrointestinal tract of Mozambique tilapia acclimated to freshwater (0 ppt), seawater (30 ppt) and hypersaline (70 ppt) environments. Among the seven genes studied, it was found that nkcc2, nkcc1a, cftr, nka-α1 and nka-α3, were more responsive to salinity challenge than nkcc1b and ncc within the investigated tissues. The ncc expression was restricted to gills of freshwater-acclimated fish while nkcc2 expression was restricted to intestinal segments irrespective of salinity challenge. Among the tissues investigated, gill and posterior intestine were found to be highly responsive to salinity changes, followed by anterior and middle intestine. Both esophagus and stomach displayed significant up-regulation of nka-α1 and nka-α3, but not nkcc isoforms and cftr, in hypersaline-acclimated fish suggesting a response to hypersalinity challenge and involvement of other forms of transporters in iono-regulation. Changes in gene expression levels were partly corroborated by immunohistochemical localization of transport proteins. Apical expression of Ncc was found in Nka-immunoreactive cells in freshwater-acclimated gills while Nkcc co-localized with Nka-immunoreactive cells expressing Cftr apically in seawater- and hypersaline-acclimated gills. In the intestine, Nkcc-stained apical brush border was found in Nka-immunoreactive cells at greater levels under hypersaline conditions. These findings provided new insights into the responsiveness of these genes and tissues under hypersalinity challenge, specifically the posterior intestine being vital for salt absorption and iono-osmoregulation in the Mozambique tilapia; its ability to survive in hypersalinity may be in part related to its ability to up-regulate key ion transporters in the posterior intestine. The findings pave the way for future iono-regulatory studies on the Mozambique tilapia esophageal-gastrointestinal tract. PMID:24498146

9 CFR 83.4 - VHS-regulated fish and VHS-regulated areas.

Code of Federal Regulations, 2014 CFR

2014-01-01

... VHS virus, with confirmation of strain identity through genetic sequencing. Anadromous fish that have... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false VHS-regulated fish and VHS-regulated... HEMORRHAGIC SEPTICEMIA § 83.4 VHS-regulated fish and VHS-regulated areas. (a)(1) APHIS will list as a VHS...

Environmentally relevant concentrations of di(2-ethylhexyl)phthalate exposure alter larval growth and locomotion in medaka fish via multiple pathways.

PubMed

Yang, Wen-Kai; Chiang, Li-Fen; Tan, Shi-Wei; Chen, Pei-Jen

2018-06-01

Di(2-ethylhexyl)phthalate (DEHP) is a commonly used plasticizer, with evidence of ubiquitous human exposure and widespread occurrence in the aquatic environment. It is an emerging environmental pollutant with regulatory priority; however, most studies have focused on the toxicity of DEHP related to endocrine disruption and reproduction in mammals. The ecotoxicological impact of phthalates (e.g., DEHP) on early life stages of fish under environmentally relevant concentrations of chronic exposure remains unclear. In this study, 7-day post-hatching fry of medaka fish (Oryzias latipes) underwent 21-day continuous exposure to DEHP solutions at 20, 100 and 200 μg/L to assess the effects on fish development and locomotion and related toxic mechanisms. Larval mortality was low with DEHP (20-200 μg/L) within 21 days, but such exposure significantly reduced fish body weight and length and altered swimming behavior. At 21 days, DEHP exposure resulted in specific patterns of larval locomotion (e.g., increased maximum velocity and absolute turn angle) and dose-dependently increased the mRNA expression of acetylcholinesterase (ache) but did not alter AChE activity. Transcriptional expression of antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase and peroxisome proliferation-activated receptor and retinoid X receptor genes was significantly suppressed with 21-day DEHP exposure (20-200 μg/L), with marginal alteration in reactive oxygen species levels and antioxidant activities within the dosing period. As well, DEHP altered the mRNA expression of p53-regulated apoptosis pathways, such as upregulated p53, p21 and bcl-2 and downregulated caspase-3 expression, with increased enzymatic activity of caspase-3 in larvae. Our results suggest that toxic mechanisms of waterborne DEHP altered fish growth and locomotion likely via a combined effect of oxidative stress, neurotoxicity and apoptosis pathways. Copyright © 2018 Elsevier B.V. All rights reserved.

Hepatic β-Oxidation and Regulation of Carnitine Palmitoyltransferase (CPT) I in Blunt Snout Bream Megalobrama amblycephala Fed a High Fat Diet

PubMed Central

Lu, Kang-Le; Xu, Wei-Na; Wang, Li-Na; Zhang, Ding-Dong; Zhang, Chun-Nuan; Liu, Wen-Bin

2014-01-01

High-fat diets may promote growth, partly through their protein-sparing effects. However, high-fat diets often lead to excessive fat deposition, which may have a negative impact on fish such as poor growth and suppressive immune. Therefore, this study investigated the effects of a fat-rich diet on the mechanisms of fat deposition in the liver. Three-hundred blunt snout bream (Megalobrama amblycephala) juveniles (initial mass 18.00±0.05 g) were fed with one of two diets (5% or 15% fat) for 8 weeks. β-Oxidation capacity and regulation of rate-limiting enzymes were assessed. Large fat droplets were present in hepatocytes of fish fed the high-fat diet. This observation is thought to be largely owing to the reduced capacity for mitochondrial and peroxisomal β-oxidation in the livers of fish fed the high-fat diet, as well as the decreased activities of carnitine palmitoyltransferase (CPT) I and acyl-CoA oxidase (ACO), which are enzymes involved in fatty-acid metabolism. Study of CPT I kinetics showed that CPT I had a low affinity for its substrates and a low catalytic efficiency in fish fed the high-fat diet. Expression of both CPT I and ACO was significantly down-regulated in fish fed the high-fat diet. Moreover, the fatty-acid composition of the mitochondrial membrane varied between the two groups. In conclusion, the attenuated β-oxidation capacity observed in fish fed a high-fat diet is proposed to be owing to decreased activity and/or catalytic efficiency of the rate-limiting enzymes CPT I and ACO, via both genetic and non-genetic mechanisms. PMID:24676148

Sex differences in neuromuscular androgen receptor expression and sociosexual behavior in a sex changing fish

PubMed Central

Pradhan, Devaleena S.; Thonkulpitak, Kevin; Drilling, Cathleen; Black, Michael; Grober, Matthew S.

2017-01-01

Androgen signaling, via receptor binding, is critical for regulating the physiological and morphological foundations of male-typical reproductive behavior in vertebrates. Muscles essential for male courtship behavior and copulation are highly sensitive to androgens. Differences in the distribution and density of the androgen receptor (AR) are important for maintaining dimorphic musculature and thus may provide for anatomical identification of sexually selected traits. In Lythrypnus dalli, a bi-directional hermaphroditic teleost fish, both sexes produce agonistic approach displays, but reproductive behavior is sexually dimorphic. The male-specific courtship behavior is characterized by rapid jerky movements (involving dorsal fin erection) towards a female or around their nest. Activation of the supracarinalis muscle is involved in dorsal fin contributions to both agonistic and sociosexual behavior in other fishes, suggesting that differences in goby sexual behavior may be reflected in sexual dimorphism in AR signaling in this muscle. We examined sex differences in the local distribution of AR in supracarinalis muscle and spinal cord. Our results demonstrate that males do express more AR in the supracarinalis muscle relative to females, but there was no sex difference in the number of spinal motoneurons expressing AR. Interestingly, AR expression in the supracarinalis muscle was also related to rates of sociosexual behavior in males, providing evidence that sexual selection may influence muscle androgenic sensitivity to enhance display vigor. Sex differences in the distribution and number of cells expressing AR in the supracarinalis muscle may underlie the expression of dimorphic behaviors in L. dalli. PMID:28520775

Tributyltin disrupts feeding and energy metabolism in the goldfish (Carassius auratus).

PubMed

Zhang, Jiliang; Sun, Ping; Yang, Fan; Kong, Tao; Zhang, Ruichen

2016-06-01

Tributyltin (TBT) can induce obesogen response. However, little is known about the adverse effects of TBT on food intake and energy metabolism. The present study was designed to investigate the effects of TBT, at environmental concentrations of 2.44 and 24.4 ng/L (1 and 10 ng/L as Sn), on feeding and energy metabolism in goldfish (Carassius auratus). After exposure for 54 d, TBT increased the weight gain and food intake in fish. The patterns of brain neuropeptide genes expression were in line with potential orexigenic effects, with increased expression of neuropeptide Y and apelin, and decreased expression of pro-opiomelanocortin, ghrelin, cocaine and amphetamine-regulated transcript, and corticotropin-releasing factor. Interestingly, the energy metabolism indicators (oxygen consumption, ammonia exertion and swimming activity) and the serum thyroid hormones were all significantly increased at the 2.44 ng/L TBT group in fish. However, no changes of energy metabolism indicators or a decrease of thyroid hormones was found at the 24.4 ng/L TBT group, which indicated a complex disrupting effect on metabolism of TBT. In short, TBT can alter feeding and energy metabolism in fish, which might promote the obesogenic responses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cloning of growth hormone, somatolactin, and their receptor mRNAs, their expression in organs, during development, and on salinity stress in the hermaphroditic fish, Kryptolebias marmoratus.

PubMed

Rhee, Jae-Sung; Kim, Bo-Mi; Seo, Jung Soo; Kim, Il-Chan; Lee, Young-Mi; Lee, Jae-Seong

2012-04-01

Salinity is an important parameter that affects survival and metabolism in fish. In fish, pituitary growth hormone (GH) regulates physiological functions including adaptation to different salinity as well as somatic growth. GH is stimulated by growth hormone-releasing hormone (GHRH) and exerts its function via binding to growth hormone receptor (GHR). As Kryptolebias marmoratus is a euryhaline fish, this species would be a useful model species for studying the adaptation to osmotic stress conditions. Here, we cloned GH, -GHR, somatolactin (SL), and somatolactin receptor (SLR) genes, and analyzed their expression patterns in different tissues and during early developmental stages by using real-time RT-PCR. We also further examined expression of them after acclimation to different salinity. Tissue distribution studies revealed that Km-GH and -SL mRNAs were remarkably expressed in brain and pituitary, whereas Km-GHR and -SLR mRNAs were predominantly expressed in liver, followed by gonad, muscle, pituitary, and brain. During embryonic developmental stages, the expression of their mRNA was increased at stage 3 (9 dpf). The Km-GH and -SL mRNA transcripts were constantly elevated until stage 5 (5h post hatch), whereas Km-GHR and -SLR mRNA levels decreased at this stage. After we transferred K. marmoratus from control (12 psu) to hyper-osmotic condition (hyperseawater, HSW; 33 psu), Km-GH, -SL, and GHR mRNA levels were enhanced. In hypo-osmotic conditions like freshwater (FW), Km-GH and -SL expressions were modulated 24 h after exposure, and Km-SLR transcripts were significantly upregulated. This finding suggests that Km-GH and -SL may be involved in the osmoregulatory mechanism under hyper-osmotic as well as hypo-osmotic stress. This is the first report on transcriptional modulation and relationship of GH, GHR, SL, and SLR during early development and after salinity stress. This study will be helpful to a better understanding on molecular mechanisms of adaptation response to salt stress in euryhaline fish. Copyright © 2012 Elsevier Inc. All rights reserved.

Dietary Lipid Sources Influence Fatty Acid Composition in Tissue of Large Yellow Croaker (Larmichthys crocea) by Regulating Triacylglycerol Synthesis and Catabolism at the Transcriptional Level

PubMed Central

Qiu, Hong; Jin, Min; Li, Yi; Lu, You; Hou, Yingmei; Zhou, Qicun

2017-01-01

An 8-week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, fatty acid composition, rate-limiting enzyme activities and gene expression related to lipid metabolism in large yellow croaker (Larmichthys crocea). Five iso-nitrogenous and iso-lipidic experimental diets were formulated to contain different lipid sources, such as fish oil (FO), soybean oil (SO), linseed oil (LO), rapeseed oil (RO) and peanut oil (PO), respectively. Triplicate groups of 50 fish (initial weight 13.77±0.07g) were stocked in 15 floating net cages (1.5m×1.5m×2.0m). Fish fed the diets containing RO and LO had lower weight gain and specific growth rates than those fed the FO, SO and PO diets. Survival, feed efficiency, protein efficiency ratio, hepatosomatic index, viscerasomatic index and condition factor were not significantly affected by different dietary lipid sources. Fish fed the diet containing FO had higher lipid content in whole body compared with the other groups, whereas fish fed the SO diet had the lowest muscle lipid content. Fatty acid profiles of muscle and liver reflected the fatty acid composition of the diets. Plasma glucose, triglyceride, and the enzymatic activity of aspartate aminotransferase and alanine aminotransferase were significantly influenced by different dietary lipid sources, while total protein, cholesterol, superoxide dismutase or malondialdehyde in plasma were not affected by the different dietary lipid sources. Fish fed the LO diet had lower adipose triglyceride lipase and fatty acid synthase activities in liver than those fed the diets containing FO and RO, while the LO diet resulted in the highest hepatic carnitine palmitoultransferase-1 activity. Hepatic gene relative expression of adipose triglyceride lipase and carnitine palmitoyltransferase-1 in fish fed PO diet was significantly higher than all other groups, whereas fish fed the SO and LO diets had lower relative expression levels of lipoprotein lipase than the other groups. The highest relative expression levels of fatty acid synthase and acyl-CoA diacylglycerol acyltransferase-2 were observed in the FO group, while the highest relative expression of glucose 6-phosphate dehydrogenase occurred in fish fed the FO and RO diets. In summary, based on the growth performance, FO and SO appear to be suitable lipid sources for large yellow croaker, with the findings of this study also providing a molecular insight into the role of lipid metabolic mechanism in response to different dietary lipid sources. PMID:28081221

Transient up- and down-regulation of expression of myosin light chain 2 and myostatin mRNA mark the changes from stratified hyperplasia to muscle fiber hypertrophy in larvae of gilthead sea bream (Sparus aurata L.).

PubMed

Georgiou, Stella; Alami-Durante, Hélène; Power, Deborah M; Sarropoulou, Elena; Mamuris, Zissis; Moutou, Katerina A

2016-02-01

Hyperplasia and hypertrophy are the two mechanisms by which muscle develops and grows. We study these two mechanisms, during the early development of white muscle in Sparus aurata, by means of histology and the expression of structural and regulatory genes. A clear stage of stratified hyperplasia was identified early in the development of gilthead sea bream but ceased by 35 dph when hypertrophy took over. Mosaic recruitment of new white fibers began as soon as 60 dph. The genes mlc2a and mlc2b were expressed at various levels during the main phases of hyperplasia and hypertrophy. The genes myog and mlc2a were significantly up-regulated during the intensive stratified formation of new fibers and their expression was significantly correlated. Expression of mstn1 and igf1 increased at 35 dph, appeared to regulate the hyperplasia-to-hypertrophy transition, and may have stimulated the expression of mlc2a, mlc2b and col1a1 at the onset of mosaic hyperplasia. The up-regulation of mstn1 at transitional phases in muscle development indicates a dual regulatory role of myostatin in fish larval muscle growth.

Toxicity of Tributyltin in Juvenile Common Carp (Cyprinus Carpio): Physiological Responses, Hepatic Gene Expression, and Stress Protein Profiling.

PubMed

Li, Zhi-Hua; Zhong, Li-Qiao; Mu, Wei-Na; Wu, Yan-Hua

2016-02-01

In this study, the effects of tributyltin (TBT) on biochemical parameters (antioxidant responses and Na(+) -K(+) -ATPase) in different tissues were investigated by using juvenile common carp (Cyprinus Carpio) as well as growth and ion regulation-related genes expression and stress-related proteins profiling in fish liver. Oxidative stress indices and Na(+) -K(+) -ATPase showed tissues-specific responses in fish exposed to different TBT concentrations. All tested genes related to GH/IGF-I axis and ion-regulation were significantly induced in the TBT group with lower concentrations (except for the igfbp3 in 10 μg/L) and were inhibited in 20 μg/L. In addition, the profiling of two proteins Hsp 70 and MT were increasing in a dose-dependent manner under TBT stress. In short, TBT-induced biochemical and molecular responses in different tissues were reflected in the measured parameters in the test. On the basis of TBT residue levels in the natural environment, more long-term experiments at lower concentrations will be necessary in the future. © 2015 Wiley Periodicals, Inc.

Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature

PubMed Central

Norambuena, Fernando; Morais, Sofia; Emery, James A.; Turchini, Giovanni M.

2015-01-01

Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad–time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature recorded a significantly increased feed intake, these results clearly suggested that at high, sub-optimal water temperature, fish metabolism attempted to increment its overall ARA status -the most bioactive LC-PUFA participating in the inflammatory response- by modulating the metabolic fate of dietary ARA (expressed as % of net intake), reducing its β-oxidation and favouring synthesis and deposition. This correlates also with results from other recent studies showing that both immune- and stress- responses in fish are up regulated in fish held at high temperatures. This is a novel and fundamental information that warrants industry and scientific attention, in consideration of the imminent increase in water temperatures, continuous expansion of aquaculture operations, resources utilisation in aquafeed and much needed seasonal/adaptive nutritional strategies. PMID:26599513

Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

PubMed

Norambuena, Fernando; Morais, Sofia; Emery, James A; Turchini, Giovanni M

2015-01-01

Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature recorded a significantly increased feed intake, these results clearly suggested that at high, sub-optimal water temperature, fish metabolism attempted to increment its overall ARA status -the most bioactive LC-PUFA participating in the inflammatory response- by modulating the metabolic fate of dietary ARA (expressed as % of net intake), reducing its β-oxidation and favouring synthesis and deposition. This correlates also with results from other recent studies showing that both immune- and stress- responses in fish are up regulated in fish held at high temperatures. This is a novel and fundamental information that warrants industry and scientific attention, in consideration of the imminent increase in water temperatures, continuous expansion of aquaculture operations, resources utilisation in aquafeed and much needed seasonal/adaptive nutritional strategies.

Cloning and expression of the translocator protein (18 kDa), voltage-dependent anion channel, and diazepam binding inhibitor in the gonad of largemouth bass (Micropterus salmoides) across the reproductive cycle.

PubMed

Doperalski, Nicholas J; Martyniuk, Christopher J; Prucha, Melinda S; Kroll, Kevin J; Denslow, Nancy D; Barber, David S

2011-08-01

Cholesterol transport across the mitochondrial membrane is rate-limiting for steroidogenesis in vertebrates. Previous studies in fish have characterized expression of the steroidogenic acute regulatory protein, however the function and regulation of other genes and proteins involved in piscine cholesterol transport have not been evaluated. In the current study, mRNA sequences of the 18 kDa translocator protein (tspo; formerly peripheral benzodiazepine receptor), voltage-dependent anion channel (vdac), and diazepam binding inhibitor (dbi; also acyl-CoA binding protein) were cloned from largemouth bass. Gonadal expression was examined across reproductive stages to determine if expression is correlated with changes in steroid levels and with indicators of reproductive maturation. In testis, transcript abundance of tspo and dbi increased with reproductive maturation (6- and 23-fold maximal increase, respectively) and expression of tspo and dbi was positively correlated with reproductive stage, gonadosomatic index (GSI), and circulating levels of testosterone. Testis vdac expression was positively correlated with reproductive stage and GSI. In females, gonadal tspo and vdac expression was negatively correlated with GSI and levels of plasma testosterone and 17β-estradiol. Ovarian dbi expression was not correlated with indicators of reproductive maturation. These studies represent the first investigation of the steroidogenic role of tspo, vdac, and dbi in fish. Findings suggest that cholesterol transport in largemouth bass testis, but not in ovary, may be transcriptionally-regulated, however further investigation will be necessary to fully elucidate the role of these genes in largemouth bass steroidogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

Anti-inflammatory effects of fish oil in ovaries of laying hens target prostaglandin pathways

PubMed Central

2013-01-01

Background An effective way to control cancer is by prevention. Ovarian cancer is the most lethal gynecological malignancy. Progress in the treatment and prevention of ovarian cancer has been hampered due to the lack of an appropriate animal model and absence of effective chemo-prevention strategies. The domestic hens spontaneously develop ovarian adenocarcinomas that share similar histological appearance and symptoms such as ascites and metastasis with humans. There is a link between chronic inflammation and cancer. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. PGE2 exerts its effects on target cells by coupling to four subtypes of receptors which have been classified as EP1-4. Fish oil is a source of omega-3 fatty acids (OM-3FAs) which may be effective in prevention of ovarian cancer. Our objective was to assess the potential impact of fish oil on expression of COX enzymes, PGE2 concentration, apoptosis and proliferation in ovaries of laying hens. Methods 48 white Leghorn hens were fed 50, 100, 175, 375 and 700 mg/kg fish oil for 21 days. The OM3-FAs and omega-6 fatty acids contents of egg yolks were determined by Gas Chromatography. Proliferation, apoptosis, COX-1, COX-2 and prostaglandin receptor subtype 4 (EP4) protein and mRNA expression and PGE2 concentration in ovaries were measured by PCNA, TUNEL, Western blot, quantitative real-time qPCR and ELISA, respectively. Results Consumption of fish oil increased the incorporation of OM-3FAs into yolks and decreased both COX-1 and COX-2 protein and mRNA expression. In correlation with COXs down-regulation, fish oil significantly reduced the concentrations of PGE2 in ovaries. EP4 protein and mRNA expression in ovaries of hens was not affected by fish oil treatment. A lower dose of fish oil increased the egg laying frequency. 175 and 700 mg/kg fish oil reduced proliferation and 700 mg/kg increased apoptosis in hen ovaries. Conclusions Our findings suggest that the lower doses of fish oil reduce inflammatory PG and may be an effective approach in preventing ovarian carcinogenesis. These findings may provide the basis for clinical trials utilizing fish oil as a dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer. PMID:24156238

Zebrafish vitamin K epoxide reductases: expression in vivo, along extracellular matrix mineralization and under phylloquinone and warfarin in vitro exposure.

PubMed

Fernández, Ignacio; Vijayakumar, Parameswaran; Marques, Carlos; Cancela, M Leonor; Gavaia, Paulo J; Laizé, Vincent

2015-06-01

Vitamin K (VK) acts as a cofactor driving the biological activation of VK-dependent proteins and conferring calcium-binding properties to them. As a result, VK is converted into VK epoxide, which must be recycled by VK epoxide reductases (Vkors) before it can be reused. Although VK has been shown to play a central role in fish development, particularly during skeletogenesis, pathways underlying VK actions are poorly understood, while good and reliable molecular markers for VK cycle/homeostasis are still lacking in fish. In the present work, expression of 2 zebrafish vkor genes was characterized along larval development and in adult tissues through qPCR analysis. Zebrafish cell line ZFB1 was used to evaluate in vitro regulation of vkors and other VK cycle-related genes during mineralization and upon 24 h exposure to 0.16 and 0.8 µM phylloquinone (VK1), 0.032 µM warfarin, or a combination of both molecules. Results showed that zebrafish vkors are differentially expressed during larval development, in adult tissues, and during cell differentiation/mineralization processes. Further, several VK cycle intermediates were differentially expressed in ZFB1 cells exposed to VK1 and/or warfarin. Present work provides data identifying different developmental stages and adult tissues where VK recycling is probably highly required, and shows how genes involved in VK cycle respond to VK nutritional status in skeletal cells. Expression of vkor genes can represent a reliable indicator to infer VK nutritional status in fish, while ZFB1 cells could represent a suitable in vitro tool to get insights into the mechanisms underlying VK action on fish bone.

Molecular characterisation of tumour necrosis factor alpha and its potential connection with lipoprotein lipase and peroxisome proliferator-activated receptors in blunt snout bream (Megalobrama amblycephala).

PubMed

Zhou, Man; Mi, Hai-Feng; Liu, Wen-Bin; Wu, Ye-Yang; Wang, Kai-Zhou; Jiang, Guang-Zhen

2017-08-01

Tumour necrosis factor alpha (TNF-α) is one kind of cytokines which is related to inflammation and lipid metabolism. TNF-α cDNA was cloned from the liver of blunt snout bream (Megalobrama amblycephala) through real-time polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE) methods. The full-length cDNA of TNF-α covered 1467 bp, with an open reading frame (ORF) of 723 bp, which encodes 240 amino acids. It possessed the TNF family signature IIIPDDGIYFVYSQ. After the lipopolysaccharide (LPS) challenge test, a graded tissue-specific expression pattern of TNF-α was observed and there was high expression abundance in the kidney, brain and liver. After 8 weeks feeding trial, liver samples, two groups fed with 6% and 11% lipid levels, were collected. The results showed that, for fish fed with high-fat diet, the triglyceride of serum and lipid content of liver were elevated. Furthermore, TNF-α and peroxisome proliferator-activated receptors (PPARα, β) mRNA expression of fish fed 11% lipid diet were significantly up-regulated (p < 0.05). Lipoprotein lipase (LPL) and PPARγ mRNA expression of fish fed 11% lipid lever diet were significantly decreased compared to those of fish fed 6% (p < 0.05). The differences between the various expression of related genes in the high and low fat groups demonstrated that TNF-α played a key role in lipid metabolism, which may have an influence on fat metabolism through reducing fat synthesis and strengthening the β-oxidation of fatty acid. These discrepancies warrant further research.

The absence of ion-regulatory suppression in the gills of the aquatic air-breathing fish Trichogaster lalius during oxygen stress.

PubMed

Huang, Chun-Yen; Lin, Hsueh-Hsi; Lin, Cheng-Huang; Lin, Hui-Chen

2015-01-01

The strategy for most teleost to survive in hypoxic or anoxic conditions is to conserve energy expenditure, which can be achieved by suppressing energy-consuming activities such as ion regulation. However, an air-breathing fish can cope with hypoxic stress using a similar adjustment or by enhancing gas exchange ability, both behaviorally and physiologically. This study examined Trichogaster lalius, an air-breathing fish without apparent gill modification, for their gill ion-regulatory abilities and glycogen utilization under a hypoxic treatment. We recorded air-breathing frequency, branchial morphology, and the expression of ion-regulatory proteins (Na(+)/K(+)-ATPase and vacuolar-type H(+)-ATPase) in the 1(st) and 4(th) gills and labyrinth organ (LO), and the expression of glycogen utilization (GP, glycogen phosphorylase protein expression and glycogen content) and other protein responses (catalase, CAT; carbonic anhydrase II, CAII; heat shock protein 70, HSP70; hypoxia-inducible factor-1α, HIF-1α; proliferating cell nuclear antigen, PCNA; superoxidase dismutase, SOD) in the gills of T. lalius after 3 days in hypoxic and restricted conditions. No morphological modification of the 1(st) and 4(th) gills was observed. The air-breathing behavior of the fish and CAII protein expression both increased under hypoxia. Ion-regulatory abilities were not suppressed in the hypoxic or restricted groups, but glycogen utilization was enhanced within the groups. The expression of HIF-1α, HSP70 and PCNA did not vary among the treatments. Regarding the antioxidant system, decreased CAT enzyme activity was observed among the groups. In conclusion, during hypoxic stress, T. lalius did not significantly reduce energy consumption but enhanced gas exchange ability and glycogen expenditure. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of chronic exposure to tributyltin on tissue-specific cytochrome P450 1 regulation in juvenile common carp.

PubMed

Li, Zhi-Hua; Zhong, Li-Qiao; Mu, Wei-Na; Wu, Yan-Hua

2016-01-01

1. The purpose of this study was to compare tributyltin (TBT)-induced cytochrome P450 1 (CYP450 1) regulation in liver, gills and muscle of juvenile common carp (Cyprinus carpio). 2. Fish were exposed to sublethal concentrations of TBT (75, 0.75 and 7.5 μg/L) for 60 days. CYP450 1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, as well as the mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) in fish tissues. 3. Based on the results, the liver displayed the highest absolute levels of EROD activity, both under nonexposed and exposed conditions. Additional, EROD activities and CYP1A gene levels showed a good correlation in all three organs. According to the mRNA expression of CYP450 1 family genes, it suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. 4. Overall, the study revealed both similarities and differences in the concentration-dependent CYP450 1 responses of the three target organs, which could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

50 CFR 300.185 - Documentation, reporting and recordkeeping requirements for consignment documents and re-export...

Code of Federal Regulations, 2011 CFR

2011-10-01

.... (3) Reporting requirements. For fish or fish products regulated under this subpart, except shark fins... this paragraph (b) apply to exports of fish or fish products regulated under this subpart, except shark... consignment of fish or fish products regulated under this subpart, except bluefin tuna or shark fins, that was...

Molecular cloning of Foxl2 gene and the effects of endocrine-disrupting chemicals on its mRNA level in rare minnow, Gobiocypris rarus.

PubMed

Wang, Houpeng; Wu, Tingting; Qin, Fang; Wang, Lihong; Wang, Zaizhao

2012-06-01

Endocrine-disrupting chemicals (EDCs) can affect normal sexual differentiation in fish. Foxl2, one forkhead transcription factor, plays an important role in ovarian differentiation in the early development of the female gonad in mammals and fish. How EDCs affect Foxl2 expression is little known. In this study, we isolated a Foxl2 cDNA from the ovary of rare minnow Gobiocypris rarus and examined its expression during early development stages and in different adult tissues. Then, we analyzed Foxl2 expression in G. rarus juvenile following 3-day exposure to 17α- ethinylestradiol (EE2), 4-n-nonylphenol (NP), and bisphenol A (BPA). Alignment of known Foxl2 sequences among vertebrates showed high identity in forkhead domain and C-terminal region with other vertebrate proteins. Quantitative RT-PCR analysis showed that Foxl2 expression was linear decrease and cyp19a1a, the downstream target gene of Foxl2, had no correlation with Foxl2 from 18 to 50 days post fertilization (dpf). Among different adult tissues, Foxl2 is mainly expressed in ovary, brain, gill, eye, and male spleen. In the 3-day exposure, the juvenile fish to EDCs, 0.1 nM EE2, and 1 nM BPA significantly up-regulated the expression of Foxl2 gene, while NP had no effect on Foxl2 expression. Altogether, these results provide basic data for further study on how Foxl2 mediates EDCs impact on the sexual differentiation in G. rarus.

Effects of azocyclotin on gene transcription and steroid metabolome of hypothalamic-pituitary-gonad axis, and their consequences on reproduction in zebrafish (Danio rerio).

PubMed

Ma, You-Ning; Cao, Chu-Yan; Wang, Qiang-Wei; Gui, Wen-Jun; Zhu, Guo-Nian

2016-10-01

The widely used organotins have the potential to disrupt the endocrine system, but little is known of underlying mechanisms of azocyclotin toxicity in fish. The objective of the present study was to investigate the impact of azocyclotin on reproduction in zebrafish. Adult zebrafish were exposed to 0.09 and 0.45μg/L azocyclotin for 21days, and effects on steroid hormones and mRNA expression of the genes belonging to the hypothalamic-pituitary-gonad (HPG) axis were investigated. Mass spectrometry methodology was developed to profile steroids within the metabolome of the gonads. They were disrupted as a result of azocyclotin exposure. Alterations in the expression of key genes associated with reproductive endocrine pathways in the pituitary (lhβ), gonad (cyp19a1a, cyp17a1 and 17β-hsd3), and liver (vtg1, vtg2, cyp1a1, comt, ugt1a and gstp1) were correlated with significant reductions in estrogen in both sexes and increased testosterone in females. Azocyclotin-induced down-regulation of cyp19a1a in males suggested a reduction in the rate of estrogen biosynthesis, while up-regulation of hepatic cyp1a1 and comt in both sexes suggested an increase in estrogen biotransformation and clearance. Azocyclotin also induced change in the expression of 17β-hsd3, suggesting increased bioavailability of 11-ketotestosterone (11-KT) in the blood. Furthermore, the down-regulation of lhβ expression in the brains of azocyclotin-exposed fish was associated with inhibition of oocyte maturation in females and retarded spermatogenesis in males. As a histological finding, retarded development of the ovaries was found to be an important cause for decreased fecundity, with down-regulation of vtg suspected to be a likely underlying mechanism. Additionally, relatively high concentrations of azocyclotin in the gonads may have directly caused toxicity, thereby impairing gametogenesis and reproduction. Embryonic or larval abnormalities occurred in the F1 generation along with accumulated burdens of azocyclotin in F1 eggs, following parental exposure. Overall, our results indicate that exposure to azocyclotin can impair reproduction in fish, and induce toxicity related abnormalities in non-exposed offspring. Copyright © 2016 Elsevier B.V. All rights reserved.

Transcriptomics of morphological color change in polychromatic Midas cichlids

PubMed Central

2013-01-01

Background Animal pigmentation has received much attention in evolutionary biology research due to its strong implications for adaptation and speciation. However, apart from a few cases the genetic changes associated with these evolutionary processes remain largely unknown. The Midas cichlid fish from Central America are an ideal model system for investigating pigmentation traits that may also play a role in speciation. Most Midas cichlids maintain their melanophores and exhibit a grayish (normal) color pattern throughout their lives. A minority of individuals, however, undergo color change and exhibit a distinctive gold or even white coloration in adulthood. The ontogenetic color change in the Midas cichlids may also shed light on the molecular mechanisms underlying pigmentation disorders in humans. Results Here we use next-generation sequencing (Illumina) RNAseq analyses to compare skin transcriptome-wide expression levels in three distinct stages of color transformation in Midas cichlids. cDNA libraries of scale tissue, for six biological replicates of each group, were generated and sequenced using Illumina technology. Using a combination of three differential expression (DE) analyses we identified 46 candidate genes that showed DE between the color morphs. We find evidence for two key DE patterns: a) genes involved in melanosomal pathways are up-regulated in normally pigmented fish; and b) immediate early and inflammatory response genes were up-regulated in transitional fish, a response that parallels some human skin disorders such as melanoma formation and psoriasis. One of the DE genes segregates with the gold phenotype in a genetic cross and might be associated with incipient speciation in this highly “species-rich” lineage of cichlids. Conclusions Using transcriptomic analyses we successfully identified key expression differences between different color morphs of Midas cichlid fish. These differentially expressed genes have important implications for our understanding of the molecular mechanisms underlying speciation in this lineage of extremely young species since they mate strongly assortatively, and new species may arise by sexual selection due to this color polymorphism. Some of the human orthologues of the genes identified here may also be involved in pigmentation differences and diseases and therefore provide genetic markers for the detection of human pigmentation disorders. PMID:23497064

Transcriptomics of morphological color change in polychromatic Midas cichlids.

PubMed

Henning, Frederico; Jones, Julia C; Franchini, Paolo; Meyer, Axel

2013-03-13

Animal pigmentation has received much attention in evolutionary biology research due to its strong implications for adaptation and speciation. However, apart from a few cases the genetic changes associated with these evolutionary processes remain largely unknown. The Midas cichlid fish from Central America are an ideal model system for investigating pigmentation traits that may also play a role in speciation. Most Midas cichlids maintain their melanophores and exhibit a grayish (normal) color pattern throughout their lives. A minority of individuals, however, undergo color change and exhibit a distinctive gold or even white coloration in adulthood. The ontogenetic color change in the Midas cichlids may also shed light on the molecular mechanisms underlying pigmentation disorders in humans. Here we use next-generation sequencing (Illumina) RNAseq analyses to compare skin transcriptome-wide expression levels in three distinct stages of color transformation in Midas cichlids. cDNA libraries of scale tissue, for six biological replicates of each group, were generated and sequenced using Illumina technology. Using a combination of three differential expression (DE) analyses we identified 46 candidate genes that showed DE between the color morphs. We find evidence for two key DE patterns: a) genes involved in melanosomal pathways are up-regulated in normally pigmented fish; and b) immediate early and inflammatory response genes were up-regulated in transitional fish, a response that parallels some human skin disorders such as melanoma formation and psoriasis. One of the DE genes segregates with the gold phenotype in a genetic cross and might be associated with incipient speciation in this highly "species-rich" lineage of cichlids. Using transcriptomic analyses we successfully identified key expression differences between different color morphs of Midas cichlid fish. These differentially expressed genes have important implications for our understanding of the molecular mechanisms underlying speciation in this lineage of extremely young species since they mate strongly assortatively, and new species may arise by sexual selection due to this color polymorphism. Some of the human orthologues of the genes identified here may also be involved in pigmentation differences and diseases and therefore provide genetic markers for the detection of human pigmentation disorders.

Hnf4α is involved in the regulation of vertebrate LC-PUFA biosynthesis: insights into the regulatory role of Hnf4α on expression of liver fatty acyl desaturases in the marine teleost Siganus canaliculatus.

PubMed

Wang, Shuqi; Chen, Junliang; Jiang, Danli; Zhang, Qinghao; You, Cuihong; Tocher, Douglas R; Monroig, Óscar; Dong, Yewei; Li, Yuanyou

2018-06-01

Long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis is an important metabolic pathway in vertebrates, especially fish, considering they are the major source of n-3 LC-PUFA in the human diet. However, most fish have only limited capability for biosynthesis of LC-PUFA. The rabbitfish (Siganus canaliculatus) is able to synthesize LC-PUFA as it has all the key enzyme activities required including Δ6Δ5 Fads2, Δ4 Fads2, Elovl5, and Elovl4. We previously reported a direct interaction between the transcription factor Hnf4α and the promoter regions of Δ4 and Δ6Δ5 Fads2, which suggested that Hnf4α was involved in the transcriptional regulation of fads2 in rabbitfish. For functionally investigating it further, a full-length cDNA of 1736-bp-encoding rabbitfish Hnf4α with 454 amino acids was cloned, which was highly expressed in intestine, followed by liver and eyes. Similar to the expression characteristics of its target genes Δ4 and Δ6Δ5 fads2, levels of hnf4α mRNA in liver and eyes were higher in fish reared at low salinity than those reared in high salinity. After the rabbitfish primary hepatocytes were, respectively, incubated with alverine, benfluorex or BI6015, which were anticipated agonists or antagonist for Hnf4α, the mRNA level of Δ6Δ5 and Δ4 fads2 displayed a similar change tendency with that of hnf4α mRNA. Furthermore, when the mRNA level of hhf4α was knocked down using siRNA, the expression of Δ6Δ5 and Δ4 fads2 also decreased. Together, these data suggest that Hnf4α is involved in the transcriptional regulation of LC-PUFA biosynthesis, specifically, by targeting Δ4 and Δ6Δ5 fads2 in rabbitfish.

Functional Categorization of Transcriptome in the Species Symphysodon aequifasciatus Pellegrin 1904 (Perciformes: Cichlidae) Exposed to Benzo[a]pyrene and Phenanthrene

PubMed Central

Lemgruber, Renato de Souza Pinto; Marshall, Nislanha Ana dos Anjos; Ghelfi, Andrea; Fagundes, Daniel Barros; Val, Adalberto Luis

2013-01-01

This study aims to evaluate the transcriptome alterations, through cDNA libraries, associated with the combined effects of two PAHs, benzo[a]pyrene (0.5 µg/L) and phenanthrene (50 µg/L), present in crude oil, on specimens of Symphysodon aequifasciatus (discus fish) after 48 h of exposure. The cDNA libraries were constructed according to the SOLiD™ SAGE™ protocol for sequencing in the SOLiD v.3 Plus sequencer. The results were analyzed by bioinformatics and differentially expressed genes were categorized using the gene ontology program. The functional categories (terms) found in the gene ontology and the gene network generated using STRING software were used to predict the adverse effects of benzo[a]pyrene and phenanthrene in the liver. In the present study, 27,127 genes (compared to Danio rerio database) were identified. Considering only those genes with a p-value less than or equal to 0.05 and greater than or equal to two-fold change in expression across libraries, we found 804 genes, 438 down-regulated (54%) and 366 up-regulated (46%), in the experimental group compared to the control. Out of this total, 327 genes were successfully categorized, 174 down-regulated and 153 up-regulated, using gene ontology. Using String, the gene network was composed by 199 nodes, 124 of them resulting in 274 interactions. The results showed that even an acute exposure of 48 h caused metabolic change in response to environmental contaminants, resulting in changes of cell integrity, in oxidation-reduction processes, in the immune response and disturbances of intracellular signaling of discus fish. Also the gene network has showed no central interplay cluster, exhibiting instead interconnected clusters interactions and connected sub-networks. These findings highlight that even an acute sublethal exposure of PAHs can cause metabolism changes that may affect survival of discus. Our findings using SOLiD coupled with SAGE-method resulted in a powerful and reliable means for gene expression analysis in discus, a non-model Amazonian fish. PMID:24312524

Linking the response of endocrine regulated genes to adverse effects on sex differentiation improves comprehension of aromatase inhibition in a Fish Sexual Development Test.

PubMed

Muth-Köhne, Elke; Westphal-Settele, Kathi; Brückner, Jasmin; Konradi, Sabine; Schiller, Viktoria; Schäfers, Christoph; Teigeler, Matthias; Fenske, Martina

2016-07-01

The Fish Sexual Development Test (FSDT) is a non-reproductive test to assess adverse effects of endocrine disrupting chemicals. With the present study it was intended to evaluate whether gene expression endpoints would serve as predictive markers of endocrine disruption in a FSDT. For proof-of-concept, a FSDT according to the OECD TG 234 was conducted with the non-steroidal aromatase inhibitor fadrozole (test concentrations: 10μg/L, 32μg/L, 100μg/L) using zebrafish (Danio rerio). Gene expression analyses using quantitative RT-PCR were included at 48h, 96h, 28days and 63days post fertilization (hpf, dpf). The selection of genes aimed at finding molecular endpoints which could be directly linked to the adverse apical effects of aromatase inhibition. The most prominent effects of fadrozole exposure on the sexual development of zebrafish were a complete sex ratio shift towards males and an acceleration of gonad maturation already at low fadrozole concentrations (10μg/L). Due to the specific inhibition of the aromatase enzyme (Cyp19) by fadrozole and thus, the conversion of C19-androgens to C18-estrogens, the steroid hormone balance controlling the sex ratio of zebrafish was altered. The resulting key event is the regulation of directly estrogen-responsive genes. Subsequently, gene expression of vitellogenin 1 (vtg1) and of the aromatase cyp19a1b isoform (cyp19a1b), were down-regulated upon fadrozole treatment compared to controls. For example, mRNA levels of vtg1 were down-regulated compared to the controls as early as 48 hpf and 96 hpf. Further regulated genes cumulated in pathways suggested to be controlled by endocrine mechanisms, like the steroid and terpenoid synthesis pathway (e.g. mevalonate (diphospho) decarboxylase (mvd), lanosterol synthase (2,3-oxidosqualene-lanosterol cyclase; lss), methylsterol monooxygenase 1 (sc4mol)) and in lipid transport/metabolic processes (steroidogenic acute regulatory protein (star), apolipoprotein Eb (apoEb)). Taken together, this study demonstrated that the existing Adverse Outcome Pathway (AOP) for aromatase inhibition in fish can be translated to the life-stage of sexual differentiation. We were further able to identify MoA-specific marker gene expression which can be instrumental in defining new measurable key events (KE) of existing or new AOPs related to endocrine disruption. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

Molecular characterization, tissue distribution and feeding related changes of NUCB2A/nesfatin-1 in Ya-fish (Schizothorax prenanti).

PubMed

Lin, Fangjun; Zhou, Chaowei; Chen, Hu; Wu, Hongwei; Xin, Zhiming; Liu, Ju; Gao, Yundi; Yuan, Dengyue; Wang, Tao; Wei, Rongbin; Chen, Defang; Yang, Shiyong; Wang, Yan; Pu, Yundan; Li, Zhiqiong

2014-02-25

The protein nucleobindin-2 (NUCB2) was identified over a decade ago and recently raised great interest as its derived peptide nesfatin-1 was shown to reduce food intake and body weight in rodents. However, the involvement of NUCB2 in feeding behavior has not well been studied in fish. In the present study, we characterized the structure, distribution, and meal responsive of NUCB2A/nesfatin-1 in Ya-fish (Schizothorax prenanti) for the first time. The full length cDNA of Ya-fish was 2140base pair (bp), which encoded a polypeptide of 487 amino acid residues including a 23 amino acid signal peptide. A high conservation in NUCB2 sequences was found in vertebrates, however the proposed propeptide cleavage site (Arg-Arg) conserved among other species is not present in Ya-fish NUCB2A sequence. Tissue distribution analysis revealed that Ya-fish NUCB2A mRNA was ubiquitously expressed in all test tissues, and abundant expression was detected in several regions including the hypothalamus, hepatopancreas, ovary and intestines. NUCB2A mRNA expression respond to feeding status change may vary and be tissue specific. NUCB2A mRNA levels significantly increased (P<0.05) in the hypothalamus and intestines after feeding and substantially decreased (P<0.01) during a week food deprivation in the hypothalamus. Meanwhile, NUCB2A mRNA in the hepatopancreas was significantly elevated (P<0.001) during food deprivation, and a similar increase was also found after short-time fasting. This points toward a potential hepatopancreas specific local role for NUCB2A in the regulation of metabolism during food deprivation. Collectively, these results provide the molecular and functional evidence to support potential anorectic and metabolic roles for NUCB2A in Ya-fish. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel insights into iron regulation and requirement in marine medaka Oryzias melastigma

NASA Astrophysics Data System (ADS)

Wang, Jian; Wang, Wen-Xiong

2016-05-01

Iron (Fe) is an essential trace element for marine fish. However, our knowledge of Fe requirements at different development stages of marine fish is still limited. Here, we reported the efficient Fe absorption strategies adopted by larval fish under different dietary Fe supplementary levels (i.e., 0-640 mg/kg). Biokinetically, the larval fish controlled their dietary Fe assimilation efficiency (AE, 1.6-18.5%), and enhanced their waterborne Fe uptake (ca. 2.5 fold change of uptake rate constant) once the dietary Fe was deficient (i.e., 27.4 mg Fe/kg feed). Transcriptionally, the expression of hepcidin1 (hep1; Fe regulator; i.e., 2.3-15.7 fold change) in larval fish was positively correlated with the Fe supplementary levels. Comparatively, the female adult fish were poor in assimilating the added Fe source (i.e., ferric form) with similar life-sustainable levels of Fe (i.e., 0.046-0.12 μg/g/d assimilated for Fe supplementary levels of 27.4, 162 and 657 mg Fe/kg feed). The overall feeding experiments suggested that dietary net Fe flux sufficient for the normal growth of larval medaka was 0.71-1.75 μg/g/d (i.e., 83.9 mg Fe/kg feed), consistent with the modeled value (i.e., 1.09-2.16 μg/g/d). In female adults, the estimated essential net Fe flux was 0.88-0.90 μg/g/d.

Lysine and Leucine Deficiencies Affect Myocytes Development and IGF Signaling in Gilthead Sea Bream (Sparus aurata)

PubMed Central

Azizi, Sheida; Nematollahi, Mohammad Ali; Mojazi Amiri, Bagher; Vélez, Emilio J.; Lutfi, Esmail; Navarro, Isabel; Capilla, Encarnación; Gutiérrez, Joaquim

2016-01-01

Optimizing aquaculture production requires better knowledge of growth regulation and improvement in diet formulation. A great effort has been made to replace fish meal for plant protein sources in aquafeeds, making necessary the supplementation of such diets with crystalline amino acids (AA) to cover the nutritional requirements of each species. Lysine and Leucine are limiting essential AA in fish, and it has been demonstrated that supplementation with them improves growth in different species. However, the specific effects of AA deficiencies in myogenesis are completely unknown and have only been studied at the level of hepatic metabolism. It is well-known that the TOR pathway integrates the nutritional and hormonal signals to regulate protein synthesis and cell proliferation, to finally control muscle growth, a process also coordinated by the expression of myogenic regulatory factors (MRFs). This study aimed to provide new information on the impact of Lysine and Leucine deficiencies in gilthead sea bream cultured myocytes examining their development and the response of insulin-like growth factors (IGFs), MRFs, as well as key molecules involved in muscle growth regulation like TOR. Leucine deficiency did not cause significant differences in most of the molecules analyzed, whereas Lysine deficiency appeared crucial in IGFs regulation, decreasing significantly IGF-I, IGF-II and IGF-IRb mRNA levels. This treatment also down-regulated the gene expression of different MRFs, including Myf5, Myogenin and MyoD2. These changes were also corroborated by a significant decrease in proliferation and differentiation markers in the Lysine-deficient treatment. Moreover, both Lysine and Leucine limitation induced a significant down-regulation in FOXO3 gene expression, which deserves further investigation. We believe that these results will be relevant for the production of a species as appreciated for human consumption as it is gilthead sea bream and demonstrates the importance of an adequate level of Lysine in fishmeal diet formulation for optimum growth. PMID:26808650

Characterization of Gonadal Transcriptomes from Nile Tilapia (Oreochromis niloticus) Reveals Differentially Expressed Genes

PubMed Central

Sun, Yunlv; Yang, Shijie; Li, Minghui; Zeng, Sheng; Huang, Baofeng; Wang, Deshou

2013-01-01

Four pairs of XX and XY gonads from Nile tilapia were sequenced at four developmental stages, 5, 30, 90, and 180 days after hatching (dah) using Illumina HiseqTM technology. This produced 28 Gb sequences, which were mapped to 21,334 genes. Of these, 259 genes were found to be specifically expressed in XY gonads, and 69 were found to be specific to XX gonads. Totally, 187 XX- and 1,358 XY-enhanced genes were identified, and 2,978 genes were found to be co-expressed in XX and XY gonads. Almost all steroidogenic enzymes, including cyp19a1a, were up-regulated in XX gonads at 5 dah; but in XY gonads these enzymes, including cyp11b2, were significantly up-regulated at 90 dah, indicating that, at a time critical to sex determination, the XX fish produced estrogen and the XY fish did not produce androgens. The most pronounced expression of steroidogenic enzyme genes was observed at 30 and 90 dah for XX and XY gonads, corresponding to the initiation of germ cell meiosis in the female and male gonads, respectively. Both estrogen and androgen receptors were found to be expressed in XX gonads, but only estrogen receptors were expressed in XY gonads at 5 dah. This could explain why exogenous steroid treatment induced XX and XY sex reversal. The XX-enhanced expression of cyp19a1a and cyp19a1b at all stages suggests an important role for estrogen in female sex determination and maintenance of phenotypic sex. This work is the largest collection of gonadal transcriptome data in tilapia and lays the foundation for future studies into the molecular mechanisms of sex determination and maintenance of phenotypic sex in non-model teleosts. PMID:23658843

The osmoregulatory effects of rearing Mozambique tilapia in a tidally changing salinity.

PubMed

Moorman, Benjamin P; Inokuchi, Mayu; Yamaguchi, Yoko; Lerner, Darren T; Grau, E Gordon; Seale, Andre P

2014-10-01

The native distribution of Mozambique tilapia, Oreochromis mossambicus, is characterized by estuarine areas subject to salinity variations between fresh water (FW) and seawater (SW) with tidal frequency. Osmoregulation in the face of changing environmental salinity is largely mediated through the neuroendocrine system and involves the activation of ion uptake and extrusion mechanisms in osmoregulatory tissues. We compared plasma osmolality, plasma prolactin (PRL), pituitary PRL mRNA, and mRNA of branchial ion pumps, transporters, channels, and PRL receptors in tilapia reared in FW, SW, brackish water (BW) and in tidally-changing salinity, which varied between FW (TF) and SW (TS) every 6h. Plasma PRL was higher in FW tilapia than in SW, BW, TF, and TS tilapia. Unlike tilapia reared in FW or SW, fish in salinities that varied tidally showed no correlation between plasma osmolality and PRL. In FW fish, gene expression of PRL receptor 1 (PRLR1), Na(+)/Cl(-) cotransporter (NCC), aquaporin 3 (AQP3) and two isoforms of Na(+)/K(+)-ATPase (NKA α1a and NKA α1b) was higher than that of SW, BW or tidally-changing salinity fish. Gene expression of the Na(+)/K(+)/2Cl(-) cotransporter (NKCC1a), and the cystic fibrosis transmembrane conductance regulator (CFTR) were higher in fish in SW, BW or a tidally-changing salinity than in FW fish. Immunocytochemistry revealed that ionocytes of fish in tidally-changing salinities resemble ionocytes of SW fish. This study indicated that tilapia reared in a tidally-changing salinity can compensate for large changes in external osmolality while maintaining osmoregulatory parameters within a narrow range closer to that observed in SW-acclimated fish. Copyright © 2014 Elsevier Inc. All rights reserved.

77 FR 56027 - 2012-2013 Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... that pertain to migratory game bird hunting, upland game hunting, big game hunting, and sport fishing... fishing regulations when we open wildlife refuges to migratory game bird hunting, upland game hunting, big game hunting, or sport fishing. These regulations list the wildlife species that you may hunt or fish...

Contextual modulation of social and endocrine correlates of fitness: insights from the life history of a sex changing fish

PubMed Central

Pradhan, Devaleena S.; Solomon-Lane, Tessa K.; Grober, Matthew S.

2015-01-01

Steroid hormones are critical regulators of reproductive life history, and the steroid sensitive traits (morphology, behavior, physiology) associated with particular life history stages can have substantial fitness consequences for an organism. Hormones, behavior and fitness are reciprocally associated and can be used in an integrative fashion to understand how the environment impacts organismal function. To address the fitness component, we highlight the importance of using reliable proxies of reproductive success when studying proximate regulation of reproductive phenotypes. To understand the mechanisms by which the endocrine system regulates phenotype, we discuss the use of particular endocrine proxies and the need for appropriate functional interpretation of each. Lastly, in any experimental paradigm, the responses of animals vary based on the subtle differences in environmental and social context and this must also be considered. We explore these different levels of analyses by focusing on the fascinating life history transitions exhibited by the bi-directionally hermaphroditic fish, Lythrypnus dalli. Sex changing fish are excellent models for providing a deeper understanding of the fitness consequences associated with behavioral and endocrine variation. We close by proposing that local regulation of steroids is one potential mechanism that allows for the expression of novel phenotypes that can be characteristic of specific life history stages. A comparative species approach will facilitate progress in understanding the diversity of mechanisms underlying the contextual regulation of phenotypes and their associated fitness correlates. PMID:25691855

Contextual modulation of social and endocrine correlates of fitness: insights from the life history of a sex changing fish.

PubMed

Pradhan, Devaleena S; Solomon-Lane, Tessa K; Grober, Matthew S

2015-01-01

Steroid hormones are critical regulators of reproductive life history, and the steroid sensitive traits (morphology, behavior, physiology) associated with particular life history stages can have substantial fitness consequences for an organism. Hormones, behavior and fitness are reciprocally associated and can be used in an integrative fashion to understand how the environment impacts organismal function. To address the fitness component, we highlight the importance of using reliable proxies of reproductive success when studying proximate regulation of reproductive phenotypes. To understand the mechanisms by which the endocrine system regulates phenotype, we discuss the use of particular endocrine proxies and the need for appropriate functional interpretation of each. Lastly, in any experimental paradigm, the responses of animals vary based on the subtle differences in environmental and social context and this must also be considered. We explore these different levels of analyses by focusing on the fascinating life history transitions exhibited by the bi-directionally hermaphroditic fish, Lythrypnus dalli. Sex changing fish are excellent models for providing a deeper understanding of the fitness consequences associated with behavioral and endocrine variation. We close by proposing that local regulation of steroids is one potential mechanism that allows for the expression of novel phenotypes that can be characteristic of specific life history stages. A comparative species approach will facilitate progress in understanding the diversity of mechanisms underlying the contextual regulation of phenotypes and their associated fitness correlates.

Relationship between expression of muscle-specific uncoupling protein 2 messenger RNA and genetic selection toward growth in channel catfish

USDA-ARS?s Scientific Manuscript database

Uncoupling protein 2 is a member of the mitochondrial channel proteins that regulate the flow of hydrogen ions and ATP generation. The relationship between UCP2 and nutrient metabolism has been well-defined in humans but unclear in fish. We hypothesized that increased muscle growth in channel catf...

The effect of acidity on gill variations in the aquatic air-breathing fish, Trichogaster lalius.

PubMed

Huang, Chun-Yen; Lin, Hui-Chen

2011-01-01

Climate change affects organisms that inhabit not only in aerial but also in aquatic environments by making water more hypoxic and acidic. In the past, we evaluated morphological and functional variations in the gills of 12 species of aquatic air-breathing fishes. The aim of the present study is to examine the degree of gill modification in the aquatic air-breathing fish, Trichogaster lalius, in response to acidic stress. This provides a link between the ecological and physiological studies. We evaluated the changes in morphology and function of the gills, labyrinth organ, and kidney when the fish were subjected to acidic water and deionized water (DW). In the first experiment, fish were sampled at 1, 2, 4, and 7 days after acidic treatment. Apparent morphological modification was observed on day 4 and recovery was noted on day 7. Protein expression and enzyme activity of vacuolar-type H+-ATPase (VHA) and the protein expression of the proliferating cell nuclear antigen (PCNA) of the 1st and 4th gill arches both increased in the 4-day and 7-day acidic groups while the enzyme activity of Na+/K+-ATPase (NKA) decreased. In the second experiment, fish were tested for changes in the 1st and 4th gill arches and kidney after exposure to DW and acidic water for 4days. The gill structure of the fish in the DW was not different from that of the control group (fresh water). The protein expression and enzyme activity of the VHA of the 1st and 4th gill arches increased in both the DW and acidic groups for 4 days. We found a decrease in the protein expression of NKA in the kidney and in the enzyme activity of NKA in the 1st and 4th gill arches in the DW and acidic groups. From these results, we suggest that T. lalius exhibited significantly different ionic regulation and acid-base regulatory abilities in the DW and acidic groups in the 1st and 4th gill arches and kidney. The responses of the gills in T. lalius were different from those fish that show apparent morphological variations between the 1st and 4th gill arches. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

New immunomodulatory role of neuropeptide Y (NPY) in Salmo salar leucocytes.

PubMed

González-Stegmaier, Roxana; Villarroel-Espíndola, Franz; Manríquez, René; López, Mauricio; Monrás, Mónica; Figueroa, Jaime; Enríquez, Ricardo; Romero, Alex

2017-11-01

Neuropeptide Y (NPY) plays different roles in mammals such as: regulate food intake, memory retention, cardiovascular functions, and anxiety. It has also been shown in the modulation of chemotaxis, T lymphocyte differentiation, and leukocyte migration. In fish, NPY expression and functions have been studied but its immunomodulatory role remains undescribed. This study confirmed the expression and synthesis of NPY in S. salar under inflammation, and validated a commercial antibody for NPY detection in teleost. Additionally, immunomodulatory effects of NPY were assayed in vitro and in vivo. Phagocytosis and superoxide anion production in leukocytes and SHK cells were induced under stimulation with a synthetic peptide. IL-8 mRNA was selectively and strongly induced in the spleen, head kidney, and isolated cells, after in vivo challenge with NPY. All together suggest that NPY is expressed in immune tissues and modulates the immune response in teleost fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular and functional characterization of the scavenger receptor CD36 in zebrafish and common carp.

PubMed

Fink, Inge R; Benard, Erica L; Hermsen, Trudi; Meijer, Annemarie H; Forlenza, Maria; Wiegertjes, Geert F

2015-02-01

CD36 is a scavenger receptor which has been studied closely in mammals where it is expressed by many different cell types and plays a role in highly diverse processes, both homeostatic and pathologic. It is among other things important in the innate immune system, in angiogenesis, and in clearance of apoptotic cells, and it is also involved in lipid metabolism and atherosclerosis. Recently, in the cephalochordate amphioxus a primitive CD36 family member was described, which was present before the divergence of CD36 from other scavenger receptor B family members, SCARB1 and SCARB2. Not much is known on the Cd36 molecule in teleost fish. We therefore studied Cd36 in both zebrafish and common carp, two closely related cyprinid fish species. Whereas a single cd36 gene is present in zebrafish, carp has two cd36 genes, and all show conserved synteny compared to mammalian CD36. The gene expression of carp cd36 is high in brain, ovary and testis but absent in immune organs. Although in mammals CD36 expression in erythrocytes, monocytes and macrophages is high, gene expression studies in leukocyte subtypes of adult carp and zebrafish larvae, including thrombocytes and macrophages provided no indication for any substantial expression of cd36 in immune cell types. Surprisingly, analysis of the cd36 promoter region does show the presence of several binding sites for transcription factors known to regulate immune responses. Overexpression of carp cd36 locates the receptor on the cell surface of mammalian cell lines consistent with the predicted topology of cyprinid Cd36 with a large extracellular domain, two transmembrane domains, and short cytoplasmic tails at both ends. Gene expression of cd36 is down-regulated during infection of zebrafish with Mycobacterium marinum, whereas knockdown of cd36 in zebrafish larvae led to higher bacterial burden upon such infection. We discuss the putative role for Cd36 in immune responses of fish in the context of other members of the scavenger receptor class B family. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global gene expression in muscle from fasted/refed trout reveals up-regulation of genes promoting myofibre hypertrophy but not myofibre production.

PubMed

Rescan, Pierre-Yves; Le Cam, Aurelie; Rallière, Cécile; Montfort, Jérôme

2017-06-07

Compensatory growth is a phase of rapid growth, greater than the growth rate of control animals, that occurs after a period of growth-stunting conditions. Fish show a capacity for compensatory growth after alleviation of dietary restriction, but the underlying cellular mechanisms are unknown. To learn more about the contribution of genes regulating hypertrophy (an increase in muscle fibre size) and hyperplasia (the generation of new muscle fibres) in the compensatory muscle growth response in fish, we used high-density microarray analysis to investigate the global gene expression in muscle of trout during a fasting-refeeding schedule and in muscle of control-fed trout displaying normal growth. The compensatory muscle growth signature, as defined by genes up-regulated in muscles of refed trout compared with control-fed trout, showed enrichment in functional categories related to protein biosynthesis and maturation, such as RNA processing, ribonucleoprotein complex biogenesis, ribosome biogenesis, translation and protein folding. This signature was also enriched in chromatin-remodelling factors of the protein arginine N-methyl transferase family. Unexpectedly, functional categories related to cell division and DNA replication were not inferred from the molecular signature of compensatory muscle growth, and this signature contained virtually none of the genes previously reported to be up-regulated in hyperplastic growth zones of the late trout embryo myotome and to potentially be involved in production of new myofibres, notably genes encoding myogenic regulatory factors, transmembrane receptors essential for myoblast fusion or myofibrillar proteins predominant in nascent myofibres. Genes promoting myofibre growth, but not myofibre formation, were up-regulated in muscles of refed trout compared with continually fed trout. This suggests that a compensatory muscle growth response, resulting from the stimulation of hypertrophy but not the stimulation of hyperplasia, occurs in trout after refeeding. The generation of a large set of genes up-regulated in muscle of refed trout may yield insights into the molecular and cellular mechanisms controlling skeletal muscle mass in teleost and serve as a useful list of potential molecular markers of muscle growth in fish.

GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.

PubMed

Nornberg, Bruna Félix; Almeida, Daniela Volcan; Figueiredo, Márcio Azevedo; Marins, Luis Fernando

2016-10-01

The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.

25 CFR 248.1 - Fishing sites subject to regulation.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Fishing sites subject to regulation. 248.1 Section 248.1... INDIAN IN-LIEU FISHING SITES § 248.1 Fishing sites subject to regulation. Use of any of the lands... March 2, 1945 (59 Stat. 22), as amended (hereinafter called “in lieu fishing sites” or “sites”) to...

25 CFR 248.1 - Fishing sites subject to regulation.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Fishing sites subject to regulation. 248.1 Section 248.1... INDIAN IN-LIEU FISHING SITES § 248.1 Fishing sites subject to regulation. Use of any of the lands... March 2, 1945 (59 Stat. 22), as amended (hereinafter called “in lieu fishing sites” or “sites”) to...

25 CFR 248.1 - Fishing sites subject to regulation.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Fishing sites subject to regulation. 248.1 Section 248.1... INDIAN IN-LIEU FISHING SITES § 248.1 Fishing sites subject to regulation. Use of any of the lands... March 2, 1945 (59 Stat. 22), as amended (hereinafter called “in lieu fishing sites” or “sites”) to...

25 CFR 248.1 - Fishing sites subject to regulation.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Fishing sites subject to regulation. 248.1 Section 248.1... INDIAN IN-LIEU FISHING SITES § 248.1 Fishing sites subject to regulation. Use of any of the lands... March 2, 1945 (59 Stat. 22), as amended (hereinafter called “in lieu fishing sites” or “sites”) to...

25 CFR 248.1 - Fishing sites subject to regulation.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Fishing sites subject to regulation. 248.1 Section 248.1... INDIAN IN-LIEU FISHING SITES § 248.1 Fishing sites subject to regulation. Use of any of the lands... March 2, 1945 (59 Stat. 22), as amended (hereinafter called “in lieu fishing sites” or “sites”) to...

Alteration of cytochrome P450 1 regulation and HSP 70 level in brain of juvenile common carp (Cyprinus carpio) after chronic exposure to tributyltin.

PubMed

Li, Zhi-Hua; Zhong, Li-Qiao; Wu, Yan-Hua; Mu, Wei-Na

2016-02-01

Tributyltin (TBT), a toxic contaminant in aquatic environments, has bio-accumulated in aquatic food webs throughout the world and can be found at toxic levels in some biota. However, the molecular mechanisms and effects of TBT are not fully understood. The aim of the present study was to investigate the effect of long-term exposure of TBT on cytochrome P450 (CYP450) 1 regulation and heat-shock proteins (HSPs) profiling in brain of freshwater teleost. The effects of long-term exposure to TBT on mRNA expression of cytochrome P450 (CYP450) 1 family genes and ethoxyresorufin O-deethylase (EROD) activity in the brain of common carp were evaluated, as well as HSP 70 level. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on EROD activity, HSP 70 level and CYP450 1 family genes expression). The mRNA expression of CYP450 1 family genes (CYP1A, CYP1B, CYP1C1 and CYP1C2) suggested that CYP1A was to accommodate most EROD activity in fish, but other CYP450 forms also involved in this proceeding. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity and could be used as potential biomarkers for monitoring the TBT pollution in the field.

Genomic dissection of conserved transcriptional regulation in intestinal epithelial cells

PubMed Central

Camp, J. Gray; Weiser, Matthew; Cocchiaro, Jordan L.; Kingsley, David M.; Furey, Terrence S.; Sheikh, Shehzad Z.; Rawls, John F.

2017-01-01

The intestinal epithelium serves critical physiologic functions that are shared among all vertebrates. However, it is unknown how the transcriptional regulatory mechanisms underlying these functions have changed over the course of vertebrate evolution. We generated genome-wide mRNA and accessible chromatin data from adult intestinal epithelial cells (IECs) in zebrafish, stickleback, mouse, and human species to determine if conserved IEC functions are achieved through common transcriptional regulation. We found evidence for substantial common regulation and conservation of gene expression regionally along the length of the intestine from fish to mammals and identified a core set of genes comprising a vertebrate IEC signature. We also identified transcriptional start sites and other putative regulatory regions that are differentially accessible in IECs in all 4 species. Although these sites rarely showed sequence conservation from fish to mammals, surprisingly, they drove highly conserved IEC expression in a zebrafish reporter assay. Common putative transcription factor binding sites (TFBS) found at these sites in multiple species indicate that sequence conservation alone is insufficient to identify much of the functionally conserved IEC regulatory information. Among the rare, highly sequence-conserved, IEC-specific regulatory regions, we discovered an ancient enhancer upstream from her6/HES1 that is active in a distinct population of Notch-positive cells in the intestinal epithelium. Together, these results show how combining accessible chromatin and mRNA datasets with TFBS prediction and in vivo reporter assays can reveal tissue-specific regulatory information conserved across 420 million years of vertebrate evolution. We define an IEC transcriptional regulatory network that is shared between fish and mammals and establish an experimental platform for studying how evolutionarily distilled regulatory information commonly controls IEC development and physiology. PMID:28850571

RNA-seq analyses of cellular responses to elevated body temperature in the high Antarctic cryopelagic nototheniid fish Pagothenia borchgrevinki.

PubMed

Bilyk, Kevin T; Cheng, C-H Christina

2014-12-01

Through evolution in the isolated, freezing (-1.9°C) Southern Ocean, Antarctic notothenioid fish have become cold-adapted as well as cold-specialized. Notothenioid cold specialization is most evident in their limited tolerance to heat challenge, and an apparent loss of the near universal inducible heat shock (HSP70) response. Beyond these it remains unclear how broadly cold specialization pervades the underlying tissue-wide cellular responses. We report the first analysis of massively parallel RNA sequencing (RNA-seq) to identify gene expression changes in the liver in response to elevated body temperature of a high-latitude Antarctic nototheniid, the highly cold-adapted and cold-specialized cryopelagic bald notothen, Pagothenia borchgrevinki. From a large (14,873) mapped set of qualified, annotated liver transcripts, we identified hundreds of significantly differentially expressed genes following two and four days of 4°C exposure, suggesting substantial transcriptional reorganization in the liver when body temperature was raised 5°C above native water temperature. Most notably, and in sharp contrast to heat stressed non-polar fish species, was a widespread down-regulation of nearly all classes of molecular chaperones including HSP70, as well as polyubiquitins that are associated with proteosomal degradation of damaged proteins. In parallel, genes involved in the cell cycle were down-regulated by day two of 4°C exposure, signifying slowing cellular proliferation; by day four, genes associated with transcriptional and translational machineries were down-regulated, signifying general slowing of protein biosynthesis. The log2 fold differential transcriptional changes are generally of small magnitudes but significant, and in total portray a broad down turn of cellular activities in response to four days of elevated body temperature in the cold-specialized bald notothen. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of seawater acclimation on mRNA levels of corticosteroid receptor genes in osmoregulatory and immune systems in trout

USGS Publications Warehouse

Yada, T.; Hyodo, S.; Schreck, C.B.

2008-01-01

Influence of environmental salinity on expression of distinct corticosteroid receptor (CR) genes, glucocorticoid receptor (GR)-1 and -2, and mineralcorticoid receptor (MR), was examined in osmoregulatory and hemopoietic organs and leucocytes of steelhead trout (Oncorhynchus mykiss). There was no significant difference in plasma cortisol levels between freshwater (FW)- or seawater (SW)-acclimated trout, whereas Na+, K+-ATPase was activated in gill of SW fish. Plasma lysozyme levels also showed a significant increase after acclimation to SW. In SW-acclimated fish, mRNA levels of GR-1, GR-2, and MR were significantly higher in gill and body kidney than those in FW. Head kidney and spleen showed no significant change in these CR mRNA levels after SW-acclimation. On the other hand, leucocytes isolated from head kidney and peripheral blood showed significant decreases in mRNA levels of CR in SW-acclimated fish. These results showed differential regulation of gene expression of CR between osmoregulatory and immune systems. ?? 2008 Elsevier Inc. All rights reserved.

An interplay between plasticity and parental phenotype determines impacts of ocean acidification on a reef fish.

PubMed

Schunter, Celia; Welch, Megan J; Nilsson, Göran E; Rummer, Jodie L; Munday, Philip L; Ravasi, Timothy

2018-02-01

The impacts of ocean acidification will depend on the ability of marine organisms to tolerate, acclimate and eventually adapt to changes in ocean chemistry. Here, we use a unique transgenerational experiment to determine the molecular response of a coral reef fish to short-term, developmental and transgenerational exposure to elevated CO 2 , and to test how these responses are influenced by variations in tolerance to elevated CO 2 exhibited by the parents. Within-generation responses in gene expression to end-of-century predicted CO 2 levels indicate that a self-amplifying cycle in GABAergic neurotransmission is triggered, explaining previously reported neurological and behavioural impairments. Furthermore, epigenetic regulator genes exhibited a within-generation specific response, but with some divergence due to parental phenotype. Importantly, we find that altered gene expression for the majority of within-generation responses returns to baseline levels following parental exposure to elevated CO 2 conditions. Our results show that both parental variation in tolerance and cross-generation exposure to elevated CO 2 are crucial factors in determining the response of reef fish to changing ocean chemistry.

High-throughput transcriptome analysis of ISAV-infected Atlantic salmon Salmo salar unravels divergent immune responses associated to head-kidney, liver and gills tissues.

PubMed

Valenzuela-Miranda, Diego; Boltaña, Sebastian; Cabrejos, Maria E; Yáñez, José M; Gallardo-Escárate, Cristian

2015-08-01

Infectious salmon anaemia virus (ISAV) is an orthomyxovirus causing high mortality in farmed Atlantic salmon (Salmo salar). The collective data from the Atlantic salmon-ISAV interactions, performed "in vitro" using various salmon cell lines and "in vivo" fish infected with different ISAV isolates, have shown a strong regulation of immune related transcripts during the infection. Despite this strong defence response, the majority of fish succumb to infections with ISAV. The deficient protection of the host against ISAV is in part due to virulence factors of the virus, which allow evade the host-defence machinery. As such, the viral replication is uninhibited and viral loads quickly spread to several tissues causing massive cellular damage before the host can develop an effective cell-mediated and humoral outcome. To interrogate the correlation of the viral replication with the host defence response, we used fish that have been infected by cohabitation with ISAV-injected salmons. Whole gene expression patterns were measured with RNA-seq using RNA extracted from Head-kidney, Liver and Gills. The results show divergent mRNA abundance of functional modules related to interferon pathway, adaptive/innate immune response and cellular proliferation/differentiation. Furthermore, gene regulation in distinct tissues during the infection process was independently controlled within the each tissue and the observed mRNA expression suggests high modulation of the ISAV-segment transcription. Importantly this is the first time that strong correlations between functional modules containing significant immune process with protein-protein affinities and viral-segment transcription have been made between different tissues of ISAV-infected fish. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selection of reference genes for expression studies with fish myogenic cell cultures.

PubMed

Bower, Neil I; Johnston, Ian A

2009-08-10

Relatively few studies have used cell culture systems to investigate gene expression and the regulation of myogenesis in fish. To produce robust data from quantitative real-time PCR mRNA levels need to be normalised using internal reference genes which have stable expression across all experimental samples. We have investigated the expression of eight candidate genes to identify suitable reference genes for use in primary myogenic cell cultures from Atlantic salmon (Salmo salar L.). The software analysis packages geNorm, Normfinder and Best keeper were used to rank genes according to their stability across 42 samples during the course of myogenic differentiation. Initial results showed several of the candidate genes exhibited stable expression throughout myogenic culture while Sdha was identified as the least stable gene. Further analysis with geNorm, Normfinder and Bestkeeper identified Ef1alpha, Hprt1, Ppia and RNApolII as stably expressed. Comparison of data normalised with the geometric average obtained from combinations of any three of these genes showed no significant differences, indicating that any combination of these genes is valid. The geometric average of any three of Hprt1, Ef1alpha, Ppia and RNApolII is suitable for normalisation of gene expression data in primary myogenic cultures from Atlantic salmon.

[Advances in the study of neuroendocrinological regulation of kisspeptin in fish reproduction].

PubMed

Zhuo, Qi

2013-10-01

Kisspeptin, a key factor in the neuroendocrinological regulation of animal reproduction, is a peptide product encoded by kiss genes, which act as the natural ligand of GPR54. Over the last decade, multiple functional molecular forms of kisspeptin have been found in vertebrate species. In fish, the major molecular structural form is kisspeptin-10. The kisspeptin/GPR54 system has multiple important functions in reproduction. This review provides an overview of our current knowledge on kisspeptin and its role in regulating fish reproductive, including the distribution and location of kisspeptin neurons in the brain, the molecular polymorphism of fish kisspeptin, functional diversity, the molecular mechanism of fish reproductive regulation, and the molecular evolution of kisspeptin as well as the co-regulation of fish reproduction by kisspeptin and other functional molecules. Perspectives on the future of kisspeptin regulation in fish reproduction are also highlighted.

Selenium Supplementation in Fish: A Combined Chemical and Biomolecular Study to Understand Sel-Plex Assimilation and Impact on Selenoproteome Expression in Rainbow Trout (Oncorhynchus mykiss)

PubMed Central

Sweetman, John; Martin, Samuel A. M.; Feldmann, Jörg; Secombes, Christopher J.

2015-01-01

Background Selenium (Se) is an essential oligonutrient, as a component of several Se-containing proteins (selenoproteins), which exert important biological functions within an organism. In livestock, Se-enriched products have been proposed as dietary supplements to be included into functional feeds for animal preventive health care. To this end, it is important to understand the optimal range of concentrations for supplementation and how long it takes to be assimilated into the organism. Methods In this study, rainbow trout (Oncorhynchus mykiss) were fed a control diet containing 0.9 g Kg-1 Se or the same diet supplemented with a Se-Yeast product (Sel-Plex) to achieve Se concentrations ranging from 1.5–8.9 g Kg-1 for a period of ten weeks. Fish were sampled every two weeks for analysis. The kinetics of Se bioaccumulation and the effects on fish selenoprotein expression was determined in different tissues combining chemical and bimolecular techniques. Results The Sel-Plex enriched diets did not have any effect on survival and growth performance. The highest Se levels were found in liver and kidney followed by muscle and blood cells. Analysis of the Se concentration factor showed that liver is able to initially regulate the amount of Se accumulated. However, with higher dietary Se level (4.8 and 8.9 g Kg-1) and longer times of exposure (10 weeks), regulation is ineffective and the Se tissue concentration increases. The expression of the selected trout selenoprotein transcripts showed an inverse correlation with Sel-Plex augmentation in most cases. In liver, kidney and blood cells the highest up-regulation of the trout selenoprotein genes was seen mostly in the group fed the diet enriched with the lowest concentration of Sel-Plex (0.5 g Kg-1) for 10 weeks. Conclusion Sel-Plex may represent an excellent Se supplement to deliver a high level of Se without provoking harm to the fish and to guarantee the maximal absorption of the element. According to our results, a dietary supplementation of Sel-Plex between 0.5 and 4 g Kg-1 may allow maximal benefits, whereas 8 g Kg-1 may be excessive for the purpose of supplementation. PMID:25978314

The effects of mitochondrial genotype on hypoxic survival and gene expression in a hybrid population of the killifish, Fundulus heteroclitus

PubMed Central

Flight, Patrick A.; Nacci, Diane; Champlin, Denise; Whitehead, Andrew; Rand, David M.

2012-01-01

The physiological link between oxygen availability and mitochondrial function is well established. However, whether or not fitness variation is associated with mitochondrial genotypes in the field remains a contested topic in evolutionary biology. In this study we draw on a population of the teleost fish, Fundulus heteroclitus, where functionally distinct subspecies hybridize, likely as a result of past glacial events. We had two specific aims: 1) to determine the effect of mtDNA genotype on survivorship of male and female fish under hypoxic stress; 2) to determine the effect of hypoxic stress, sex and mtDNA genotype on gene expression. We found an unexpected and highly significant effect of sex on survivorship under hypoxic conditions, but no significant effect of mtDNA genotype. Gene expression analyses revealed hundreds of transcripts differentially regulated by sex and hypoxia. Mitochondrial transcripts and other predicted pathways were among those influenced by hypoxic stress, and a transcript corresponding to the mtDNA control region was the most highly suppressed transcript under conditions of hypoxia. An RT-PCR experiment on the control region was consistent with microarray results. Effects of mtDNA sequence variation on genome expression were limited, however a potentially important epistasis between mtDNA sequence and expression of a nuclear-encoded mitochondrial translation protein was discovered. Overall, these results confirm that mitochondrial regulation is a major component of hypoxia tolerance and further suggest that purifying selection has been the predominant selective force on mitochondrial genomes in these two subspecies. PMID:21980951

Receptors rather than signals change in expression in four physiological regulatory networks during evolutionary divergence in threespine stickleback.

PubMed

Di Poi, Carole; Bélanger, Dominic; Amyot, Marc; Rogers, Sean; Aubin-Horth, Nadia

2016-07-01

The molecular mechanisms underlying behavioural evolution following colonization of novel environments are largely unknown. Molecules that interact to control equilibrium within an organism form physiological regulatory networks. It is essential to determine whether particular components of physiological regulatory networks evolve or if the network as a whole is affected in populations diverging in behavioural responses, as this may affect the nature, amplitude and number of impacted traits. We studied the regulation of four physiological regulatory networks in freshwater and marine populations of threespine stickleback raised in a common environment, which were previously characterized as showing evolutionary divergence in behaviour and stress reactivity. We measured nineteen components of these networks (ligands and receptors) using mRNA and monoamine levels in the brain, pituitary and interrenal gland, as well as hormone levels. Freshwater fish showed higher expression in the brain of adrenergic (adrb2a), serotonergic (htr2a) and dopaminergic (DRD2) receptors, but lower expression of the htr2b receptor. Freshwater fish also showed higher expression of the mc2r receptor of the glucocorticoid axis in the interrenals. Collectively, our results suggest that the inheritance of the regulation of these networks may be implicated in the evolution of behaviour and stress reactivity in association with population divergence. Our results also suggest that evolutionary change in freshwater threespine stickleback may be more associated with the expression of specific receptors rather than with global changes of all the measured constituents of the physiological regulatory networks. © 2016 John Wiley & Sons Ltd.

Endoplasmic reticulum stress increases AT1R mRNA expression via TIA-1-dependent mechanism

PubMed Central

Backlund, Michael; Paukku, Kirsi; Kontula, Kimmo K.; Lehtonen, Jukka Y.A.

2016-01-01

As the formation of ribonucleoprotein complexes is a major mechanism of angiotensin II type 1 receptor (AT1R) regulation, we sought to identify novel AT1R mRNA binding proteins. By affinity purification and mass spectroscopy, we identified TIA-1. This interaction was confirmed by colocalization of AT1R mRNA and TIA-1 by FISH and immunofluorescence microscopy. In immunoprecipitates of endogenous TIA- 1, reverse transcription-PCR amplified AT1R mRNA. TIA-1 has two binding sites within AT1R 3′-UTR. The binding site proximal to the coding region is glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-dependent whereas the distal binding site is not. TIA-1 functions as a part of endoplasmic reticulum (ER) stress response leading to stress granule (SG) formation and translational silencing. We and others have shown that AT1R expression is increased by ER stress-inducing factors. In unstressed cells, TIA-1 binds to AT1R mRNA and decreases AT1R protein expression. Fluorescence microscopy shows that ER stress induced by thapsigargin leads to the transfer of TIA-1 to SGs. In FISH analysis AT1R mRNA remains in the cytoplasm and no longer colocalizes with TIA-1. Thus, release of TIA-1-mediated suppression by ER stress increases AT1R protein expression. In conclusion, AT1R mRNA is regulated by TIA-1 in a ER stress-dependent manner. PMID:26681690

Hericium caput-medusae (Bull.:Fr.) Pers. polysaccharide enhance innate immune response, immune-related genes expression and disease resistance against Aeromonas hydrophila in grass carp (Ctenopharyngodon idella).

PubMed

Gou, Changlong; Wang, Jiazhen; Wang, Yuqiong; Dong, Wenlong; Shan, Xiaofeng; Lou, Yujie; Gao, Yunhang

2018-01-01

The objective was to add 0, 400, 800 or 1200 mg/kg of Hericium caput-medusae polysaccharide (HCMP) to the basal diet of grass carp (Ctenopharyngodon idella) and determine effects on humoral innate immunity, expression of immune-related genes and disease resistance. Adding HCMP enhanced (P < 0.05) bactericidal activity at 1, 2 and 3 weeks and also lysozyme activity, complement C3, and SOD activity at 2 and 3 weeks. Supplementing 800 or 1200 mg/kg of HCMP for 2 or 3 weeks increased (P < 0.05) serum concentrations of total protein, albumin and globulin. Two immune-related genes (IL-1β and TNF-α) were up-regulated (P < 0.05) in HCMP supplemented groups given 800 or 1200 mg/kg HCMP after 2 and 3 weeks of feeding. Expression of anti-inflammatory cytokine IL-10 was down-regulated (P < 0.05) after receiving 800 or 1200 mg/kg HCMP for 2 or 3 weeks. Fish fed 800 mg/kg HCMP had maximal disease resistance against Aeromonas hydrophila (65.4%). In conclusion, HCMP enhanced immune response and expression of immune-related genes and increased disease resistance against Aeromonas hydrophila in grass carp, with greatest effects in fish given 800 mg/kg HCMP for 3 weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides)

PubMed Central

Annis, Mandy L.; Brumbaugh, William G.; Chasar, Lia C.; Denslow, Nancy D.; Tillitt, Donald E.

2014-01-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates. PMID:24694518

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides).

PubMed

Richter, Catherine A; Martyniuk, Christopher J; Annis, Mandy L; Brumbaugh, William G; Chasar, Lia C; Denslow, Nancy D; Tillitt, Donald E

2014-07-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates. Published by Elsevier Inc.

Methylmercury-induced changes in gene transcription associated with neuroendocrine disruption in largemouth bass (Micropterus salmoides)

USGS Publications Warehouse

Richter, Catherine A.; Martyniuk, Christopher J.; Annis, Mandy L.; Brumbaugh, William G.; Chasar, Lia C.; Denslow, Nancy D.; Tillitt, Donald E.

2014-01-01

Methyl-mercury (MeHg) is a potent neuroendocrine disruptor that impairs reproductive processes in fish. The objectives of this study were to (1) characterize transcriptomic changes induced by MeHg exposure in the female largemouth bass (LMB) hypothalamus under controlled laboratory conditions, (2) investigate the health and reproductive impacts of MeHg exposure on male and female largemouth bass (LMB) in the natural environment, and (3) identify MeHg-associated gene expression patterns in whole brain of female LMB from MeHg-contaminated habitats. The laboratory experiment was a single injection of 2.5 μg MeHg/g body weight for 96 h exposure. The field survey compared river systems in Florida, USA with comparably lower concentrations of MeHg (Wekiva, Santa Fe, and St. Johns Rivers) in fish and one river system with LMB that contained elevated concentrations of MeHg (St. Marys River). Microarray analysis was used to quantify transcriptomic responses to MeHg exposure. Although fish at the high-MeHg site did not show overt health or reproductive impairment, there were MeHg-responsive genes and pathways identified in the laboratory study that were also altered in fish from the high-MeHg site relative to fish at the low-MeHg sites. Gene network analysis suggested that MeHg regulated the expression targets of neuropeptide receptor and steroid signaling, as well as structural components of the cell. Disease-associated gene networks related to MeHg exposure, based upon expression data, included cerebellum ataxia, movement disorders, and hypercalcemia. Gene responses in the CNS are consistent with the documented neurotoxicological and neuroendocrine disrupting effects of MeHg in vertebrates.

32 CFR 770.3 - Fishing regulations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Fishing regulations. 770.3 Section 770.3... LIMITING PUBLIC ACCESS TO PARTICULAR INSTALLATIONS Hunting and Fishing at Marine Corps Base, Quantico, Virginia § 770.3 Fishing regulations. (a) All persons possessing the proper state license and Base permit...

32 CFR 770.3 - Fishing regulations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Fishing regulations. 770.3 Section 770.3... LIMITING PUBLIC ACCESS TO PARTICULAR INSTALLATIONS Hunting and Fishing at Marine Corps Base, Quantico, Virginia § 770.3 Fishing regulations. (a) All persons possessing the proper state license and Base permit...

32 CFR 770.3 - Fishing regulations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Fishing regulations. 770.3 Section 770.3... LIMITING PUBLIC ACCESS TO PARTICULAR INSTALLATIONS Hunting and Fishing at Marine Corps Base, Quantico, Virginia § 770.3 Fishing regulations. (a) All persons possessing the proper state license and Base permit...

Comparison of the responses of different recombinant fish type I interferons against betanodavirus infection in grouper.

PubMed

Kuo, Hsiang-Ping; Chung, Chia-Ling; Hung, Yu-Fang; Lai, Yu-Shen; Chiou, Pinwen P; Lu, Ming-Wei; Kong, Zwe-Ling

2016-02-01

The nervous necrosis virus (NNV) is an aquatic virus that can infect more than 30 species including the grouper, which is a valuable fish species in Taiwan. NNV causes up to 90-100% mortality in the aquaculture industry. Interferons (IFNs) are a family of cytokines that stimulate the expression of numerous proteins to protect the host against viruses and possess very unique specific characteristics in fish. The cross-reactivity of heterologous IFNs on grouper cells and larvae has not been well-studied to date. To evaluate and compare the anti-NNV effect of different fish IFNs in grouper, we successfully synthesized, subcloned, expressed and purified several fish type I IFNs in the present study: grouper (gIFN), salmon (sIFN), seabass (sbIFN) and tilapia (tpIFN). The gIFN and sIFN proteins up-regulated myxovirus resistance protein (Mx) gene expression in grouper kidney (GK) cells, but similar effects were not observed for sbIFN and tpIFN. Following co- and pre-treatment with the 4 types of IFNs with NNV infection in GK cells, sIFN exhibited the strongest antiviral ability to suppress NNV gene replication (especially at 24 h) and significantly reduced the cytopathic effect (CPE) at 72 h, followed by gIFN. Unsurprisingly, sbIFN and tpIFN had no significant effect on CPE but slightly suppressed NNV gene replication. The cytotoxicity of these four fish IFNs on GK cells was also examined for the first time. In the in vivo test, we confirmed that gIFN and sIFN had a significant protective effect against NNV when administered by intraperitoneal (IP) injection and the oral route in Malabar grouper (Epinephelus malabaricus) larvae. This study compared the protective effects of IFNs from various fish species against NNV and demonstrated crosstalk between sIFN and grouper cells for the first time. These results provide information concerning the efficacy of fish IFNs for possible therapeutic applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of conserved genes triggering puberty in European sea bass males (Dicentrarchus labrax) by microarray expression profiling.

PubMed

Blázquez, Mercedes; Medina, Paula; Crespo, Berta; Gómez, Ana; Zanuy, Silvia

2017-06-05

Spermatogenesis is a complex process characterized by the activation and/or repression of a number of genes in a spatio-temporal manner. Pubertal development in males starts with the onset of the first spermatogenesis and implies the division of primary spermatogonia and their subsequent entry into meiosis. This study is aimed at the characterization of genes involved in the onset of puberty in European sea bass, and constitutes the first transcriptomic approach focused on meiosis in this species. European sea bass testes collected at the onset of puberty (first successful reproduction) were grouped in stage I (resting stage), and stage II (proliferative stage). Transition from stage I to stage II was marked by an increase of 11ketotestosterone (11KT), the main fish androgen, whereas the transcriptomic study resulted in 315 genes differentially expressed between the two stages. The onset of puberty induced 1) an up-regulation of genes involved in cell proliferation, cell cycle and meiosis progression, 2) changes in genes related with reproduction and growth, and 3) a down-regulation of genes included in the retinoic acid (RA) signalling pathway. The analysis of GO-terms and biological pathways showed that cell cycle, cell division, cellular metabolic processes, and reproduction were affected, consistent with the early events that occur during the onset of puberty. Furthermore, changes in the expression of three RA nuclear receptors point at the importance of the RA-signalling pathway during this period, in agreement with its role in meiosis. The results contribute to boost our knowledge of the early molecular and endocrine events that trigger pubertal development and the onset of spermatogenesis in fish. These include an increase in 11KT plasma levels and changes in the expression of several genes involved in cell proliferation, cell cycle progression, meiosis or RA-signalling pathway. Moreover, the results can be applied to study meiosis in this economically important fish species for Mediterranean countries, and may help to develop tools for its sustainable aquaculture.

Evaluation of ToxA and Vibrio parahaemolyticus lysate on humoral immune response and immune-related genes in Pacific red snapper.

PubMed

Reyes-Becerril, Martha; Maldonado-García, Minerva; Guluarte, Crystal; León-Gallo, Amalia; Rosales-Mendoza, Sergio; Ascencio, Felipe; Hirono, Ikuo; Angulo, Carlos

2016-09-01

Immunogenicity of ToxA and Vibrio parahaemolyticus lysate was evaluated in a double immunostimulation scheme in Pacific red snapper after V. parahaemolyticus infection. Three groups of Pacific red snapper were intraperitonealy (i.p.) injected with phosphate-buffered saline (PBS group), ToxA of V. parahaemolyticus (ToxA-Vp group) or V. parahaemolyticus lysate (lysate-Vp group) (first injection, day 1; second injection, day 7). Fish were subsequently infected with live V. parahaemolyticus. Humoral immune parameters in skin mucus and serum were evaluated on days 1, 7, 8 and 14 days post-immunostimulation and 7 days post-infection. Moreover expression of immune-related genes was quantified by real time PCR in head-kidney leukocytes, spleen, liver, and intestine. The ToxA-Vp-treated group showed a higher anti-protease and catalase activity in skin mucus when compared with the PBS group. Measurements of SOD and CAT activities showed an increment in both activities a day after the second boost with ToxA-Vp or lysate-Vp. Interestingly, IgM levels in mucus and transcripts were enhanced followed the ToxA-Vp treatment even after challenge. Furthermore, IL-1β was strongly expressed in all analyzed cell or tissues followed ToxA-Vp or Vp-lysate treatments. Finally, SOD and CAT gene expression was up-regulated in fish immunostimulated with either treatment ToxA-Vp or lysate-Vp, mainly after infection in head-kidney leukocytes and intestine. This is the first study where the effects of ToxA from V. parahaemolyticus in the immune system of Pacific red snapper was evaluated. These results suggest that ToxA-Vp would positively affect humoral immune response and up-regulate expression of genes involved in the immune system function; and could help in the control of V. parahaemolyticus infection in Pacific red snapper Lutjanus peru, an economic important fish in Mexico. Copyright © 2016 Elsevier Ltd. All rights reserved.

The flagellar master operon flhDC is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri.

PubMed

Jozwick, A K S; Graf, J; Welch, T J

2017-03-01

To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of a constructed flhD mutation to a naturally occurring fliR mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. Yersinia ruckeri flhD and fliR mutants were constructed in a motile strain. Both mutations caused loss-of-motility, ablation of flagellin synthesis and phospholipase secretion, similar to naturally occurring BT2 strains. Transcriptome analysis confirmed flhDC regulation of flagellar, chemotaxis and phospholipase loci as well as other genes of diverse function. The flhD mutation confers a competitive advantage within the fish host when compared with its parent strain, while this advantage was not seen with the naturally occurring fliR mutation. An intact flhD is necessary for expression of the flagellar secretion system as well as other diverse loci, consistent with a role for flhD as a pleiotropic regulator. The maintenance of the flhD locus in Y. ruckeri strains suggests its importance for aspects of Y. ruckeri biology other than virulence, since the flhD mutation conferred a competitive advantage during experimental challenge of rainbow trout. Yersinia ruckeri is the causative agent of enteric red mouth disease, an invasive septicaemia that affects farmed salmonid fish species. Disease outbreaks can cause severe economic losses in aquaculture. BT2 variants, which have independently emerged worldwide, are an increasing threat to farmed fish production. Knowledge of mechanisms involved in virulence, conserved functions and gene regulation among strains may be exploited for the development of novel disease control strategies to prevent pathogen growth or virulence phenotypes within aquaculture. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Atrazine affects kidney and adrenal hormones (AHs) related genes expressions of rare minnow (Gobiocypris rarus).

PubMed

Yang, Lihua; Zha, Jinmiao; Li, Wei; Li, Zhaoli; Wang, Zijian

2010-05-05

Atrazine, one of the most widely used herbicides, has been proved to interfere with sexual hormones. However few studies have considered the effects of atrazine on adrenal hormones (AH). In this study, rare minnow (Gobiocypris rarus) was exposed to 0, 3, 10, 33, 100 and 333microg/l atrazine for 28 days. The histopathology of kidney and gill was examined and the expressions of AHs-related genes including Na(+),K(+)-ATPase, glucocorticoid receptor (gr), heat shock protein 70 (hsp70), and heat shock protein 90 (hsp90) in kidney and gill were quantitatively determined. Histopathological observation revealed obvious lesions in gill including hyperplasia, necrosis in epithelium region, aneurysm and lamellar fusion at concentrations as low as 10microg/l. The observed lesions in kidney included extensive expansion in the lumen, degenerative and necrotic changes of the tubular epithelia, shrinkage of the glomerulus as well as increase of the Bowman's space at concentrations as low as 10microg/l. The expressions of Na(+),K(+)-ATPase, gr, hsp70 and hsp90 in the kidney of females were significantly decreased at all concentrations. For males, the expressions of hsp90 in the kidney of all treated groups were significantly down-regulated, while gr at all concentrations and hsp70 at 10, 33, 100microg/l were significantly up-regulated. However in the gill, the expressions of these genes were not significantly different from the control. These results indicated that exposure to atrazine caused impairments of kidney and gill of fish at environmental related concentrations. Histopathological lesions could partly attribute to the changes of the expressions of AHs-related genes in kidney. We concluded also that atrazine is a potential AHs-disruptor and AHs-related genes in kidney of fish could be used as sensitive molecular biomarkers.

Toll-like receptor 22 of gilthead seabream, Sparus aurata: molecular cloning, expression profiles and post-transcriptional regulation.

PubMed

Muñoz, Iciar; Sepulcre, María Pilar; Meseguer, José; Mulero, Victoriano

2014-05-01

TLR22 is a fish-specific TLR that recognizes dsRNAs. In the present study, a TLR22 homologue gene from gilthead seabream (sbTLR22) was identified and characterized. The full coding sequence contained a single open-reading frame of 2895 nucleotides encoding a predicted protein of 964 amino acids in length. Its 3'-UTR was relatively long, 1380 nucleotides, and contained three AU-rich sequences frequently associated with mRNA instability. Functional studies showed that the sbTLR22 transcript had a short half-life, although the three AU-rich sequences in its 3'-UTR did not seem to be related with this fact. The sbTLR22 was highly expressed in the spleen, thymus and gills of healthy fish. After Vibrio anguillarum infection, the mRNA levels of sbTLR22 increased greatly in head kidney, blood and peritoneal exudate, but were only moderately induced in spleen and liver, suggesting the involvement of sbTLR22 in the immune response against bacterial infections. In addition, acidophilic granulocytes and macrophages, both considered professional phagocytes in seabream, displayed cell-type-specific sbTLR22 expression profiles when stimulated with different pathogen-associated molecular patterns (PAMPs). Although acidophilic granulocytes expressed sbTLR22, polyinosinic:polycytidylic acid (poly I:C) was unable to up-regulate the expression of this receptor. In contrast, poly I:C induced the expression of sbTLR22 in macrophages, in a process that was partially endosome-dependent. Taken together, our results suggest that sbTLR22 is involved in bacterial infection and might sense bacterial PAMPs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Gene expression fingerprints of largemouth bass (Micropterus salmoides) exposed to pulp and paper mill effluents.

PubMed

Denslow, Nancy D; Kocerha, Jannet; Sepúlveda, Maria S; Gross, Timothy; Holm, Stewart E

2004-08-18

Effluents from pulp and paper mills that historically have used elemental chlorine in the bleaching process have been implicated in inhibiting reproduction in fish. Compounds with estrogenic and androgenic binding affinities have been found in these effluents, suggesting that the impairment of reproduction is through an endocrine-related mode of action. To date, a great deal of attention has been paid to phytoestrogens and resin acids that are present in mill process streams as a result of pulping trees. Estrogen and estrogen mimics interact directly with the estrogen receptor and have near immediate effects on gene transcription by turning on the expression of a unique set of genes. Using differential display (DD) RT-PCR, we examined changes in gene expression induced by exposure to paper mill effluents. Largemouth bass were exposed to 0, 10, 20, 40, and 80% paper mill effluent concentrations in large flow-through tanks for varied periods of time including 7, 28 or 56 days. Plasma hormone levels in males and females and plasma vitellogenin (Vtg) in females decreased with dose and time. Measurements of changes in gene expression using DD RT-PCR suggest that the gene expression patterns of male fish do not change much with exposure, except for the induction of a few genes including CYP 1A, a protein that is induced through the action of the Ah receptor in response to dioxin and similar polyaromatic hydrocarbons. However, in the case of females, exposure to these effluents resulted in an up-regulation of CYP 1A that was accompanied by a generalized down-regulation of genes normally expressed during the reproductive season. These antiestrogenic changes are in agreement with previous studies in bass exposed to these effluents, and could result in decreased reproductive success in affected populations.

Single or combined effects of Lactobacillus sakei and inulin on growth, non-specific immunity and IgM expression in leopard grouper (Mycteroperca rosacea).

PubMed

Reyes-Becerril, Martha; Ascencio, Felipe; Gracia-Lopez, Vicente; Macias, Ma Esther; Roa, Marcos Cadena; Esteban, María Ángeles

2014-08-01

The aim of this study was to evaluate the single or combined effects of Lactobacillus sakei with inulin suitable for immunological in vivo studies in farmed fish. By in vitro assays, L. sakei strain 5-4 showed antibacterial activities against all assayed fish pathogens (except the Vibrio harveyi strain CAIM-1793). L. sakei was able to survive at high fish bile concentrations. Fermentation of the agave inulin resulted in a large increase in number of lactobacilli. For the in vivo study, fish were fed for 8 weeks four practical diets: control diet (control), L. sakei 5-4 (10(7) CFU/g), inulin (1% or 10 g/kg) and L. sakei + inulin (10(7) CFU/g + 10 g/kg). The weight gain showed clearly the synergistic effect of L. sakei 5-4 and inulin at 6 and 8 weeks of treatments. Leopard grouper fed with L. sakei alone or combined with inulin have significantly increased the assayed physiological and humoral immune parameters. By real-time PCR assays, the mRNA transcripts of immunoglobulin M (IgM) were found to be higher expressed in intestine, head kidney, mucus, gill, spleen and skin. Moreover, mRNA expression levels of IgM in head kidney and anterior intestine were measured by real-time PCR. L. sakei 5-4 and L. sakei + inulin supplemented diet up-regulated the expression of IgM at week 4 and 8 in intestine and head kidney, respectively. These results support the idea that the L. sakei 5-4 alone or combined with agave inulin improved growth performance and stimulates the immune system of leopard grouper.

Divergent functions of fibroblast growth factor receptor-like 1 genes in grass carp (Ctenopharyngodon idella).

PubMed

Lin, Si-Tong; Zheng, Guo-Dong; Sun, Yi-Wen; Chen, Jie; Jiang, Xia-Yun; Zou, Shu-Ming

2015-09-01

Fibroblast growth factor receptor-like 1 (FGFRL1) is a novel FGF receptor (FGFR) lacking an intracellular tyrosine kinase domain. FGFRs control the proliferation, differentiation and migration of cells in various tissues. However the functions of FGFRL1 in teleost fish are currently unknown. In this study, we report the identification of two fgfrl1 genes in grass carp (Ctenopharyngodon idella) that share 56% amino acid sequence identity. Both fgfrl1a and 1b were transcribed throughout embryogenesis, and mRNA levels were particularly high during somitogenesis. Using in situ hybridization, fgfrl1a transcripts were detected in notochord, somites, brain and eye at 14, 24 and 36 h post fertilization (hpf). In contrast, fgfrl1b was transcribed mainly in the endoderm at 14 hpf, in the gut and proctodeum at 24 hpf, and in the lens, pharyngeal arch and proctodeum at 36 hpf. In adult fish, fgfrl1a was abundantly expressed in heart, brain and muscle, while fgfrl1b was expressed strongly in eye, muscle and gill. Furthermore, both genes were significantly (p<0.05) up-regulated in muscle and brain during starvation and returned to normal levels rapidly after re-feeding. Exogenous treatment with different doses of human growth hormone down-regulated the expression of both genes in brain and muscle (p<0.05). These results suggest that Fgfrl1a and 1b play divergent roles in regulating growth and development in grass carp. Copyright © 2015 Elsevier Inc. All rights reserved.

76 FR 59304 - 2011-2012 Refuge-Specific Hunting and Sport Fishing Regulations; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-26

...-0038; 93270-1265-0000-4A] RIN 1018-AX54 2011-2012 Refuge-Specific Hunting and Sport Fishing Regulations... our regulations concerning hunting and sport fishing programs at national wildlife refuges... part 32 concerning hunting and sport fishing programs at national wildlife refuges. The final rule...

UV and hydrogen peroxide treatment restores changes in innate immunity caused by exposure of fish to reuse water.

PubMed

Singh, Arvinder; Havixbeck, Jeffrey J; Smith, Matthew K; Shu, Zengquan; Tierney, Keith B; Barreda, Daniel R; El-Din, Mohamed Gamal; Belosevic, Miodrag

2015-03-15

The purpose of this study was to assess the innate immunity of goldfish exposed to reuse water, and UV/H2O2-treated reuse water, using a real-time flow-through exposure system. The reuse water generated by ultrafiltration of finished wastewater from the municipal wastewater treatment plant was analyzed for the presence of a panel of 20 herbicides/fungicides and 46 pharmaceuticals and personal care products (PPCP). There was a seasonal variation in the profile and concentrations of xenobiotics in reuse water with lowest levels occurring in the summer. The innate immunity parameters assessed were cytokine (IFNγ, IL-1β, IL-10, TNFα2), and cytokine receptor (TNFR1, TNFR2, IFNGR1, IFNGR2) gene expression, and phagocytosis of kidney leukocyte subpopulations. Assessment of innate immunity parameters was done after acute (7 days) and sub chronic (30 and 60 days) exposure to reuse water, UV/H2O2-treated reuse water, and activated carbon-treated reuse water (ACT; control), during spring, summer and fall of 2012. Temporal (acute versus sub chronic) as well as seasonal differences in innate immunity of fish exposed to reuse water were observed. The acute exposure of fish to reuse water caused significant down-regulation in cytokine gene expression in different organs of fish (kidney, spleen, liver) and phagocytic ability of different kidney leukocyte subpopulations. The immune gene expression and phagocytosis of kidney leukocytes of fish returned to ACT control levels after sub chronic exposure suggesting that fish have habituated to the reuse water exposure. The changes in gene expression after acute exposure were related to variations in the profile of xenobiotics in reuse water during different seasons. The efficiency of xenobiotic removal using UV/H2O2 ranged between 1.6 and 100% indicating that treatment of reuse water using high dose UV/H2O2 was only partially effective in removing the xenobiotics, as assessed by both chemical analyses and measurement of innate immune responsiveness of the fish. Furthermore, exposure of fish to reuse water and UV/H2O2-treated reuse water generated in the spring and fall caused greater changes in innate immunity after acute exposure, compared to fish exposed to ACT reuse water, indicating that the remediation of reuse water, should be considered in order to protect aquatic and public health. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gene expression networks underlying ovarian development in wild largemouth bass (Micropterus salmoides).

PubMed

Martyniuk, Christopher J; Prucha, Melinda S; Doperalski, Nicholas J; Antczak, Philipp; Kroll, Kevin J; Falciani, Francesco; Barber, David S; Denslow, Nancy D

2013-01-01

Oocyte maturation in fish involves numerous cell signaling cascades that are activated or inhibited during specific stages of oocyte development. The objectives of this study were to characterize molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in wild female largemouth bass to improve understanding of the molecular sequence of events underlying oocyte maturation. Transcriptomic analysis was performed on eight morphologically diverse stages of the ovary, including primary and secondary stages of oocyte growth, ovulation, and atresia. Ovary histology, plasma vitellogenin, 17β-estradiol, and testosterone were also measured to correlate with gene networks. Global expression patterns revealed dramatic differences across ovarian development, with 552 and 2070 genes being differentially expressed during both ovulation and atresia respectively. Gene set enrichment analysis (GSEA) revealed that early primary stages of oocyte growth involved increases in expression of genes involved in pathways of B-cell and T-cell receptor-mediated signaling cascades and fibronectin regulation. These pathways as well as pathways that included adrenergic receptor signaling, sphingolipid metabolism and natural killer cell activation were down-regulated at ovulation. At atresia, down-regulated pathways included gap junction and actin cytoskeleton regulation, gonadotrope and mast cell activation, and vasopressin receptor signaling and up-regulated pathways included oxidative phosphorylation and reactive oxygen species metabolism. Expression targets for luteinizing hormone signaling were low during vitellogenesis but increased 150% at ovulation. Other networks found to play a significant role in oocyte maturation included those with genes regulated by members of the TGF-beta superfamily (activins, inhibins, bone morphogenic protein 7 and growth differentiation factor 9), neuregulin 1, retinoid X receptor, and nerve growth factor family. This study offers novel insight into the gene networks underlying vitellogenesis, ovulation and atresia and generates new hypotheses about the cellular pathways regulating oocyte maturation.

Diet × genotype interactions in hepatic cholesterol and lipoprotein metabolism in Atlantic salmon (Salmo salar) in response to replacement of dietary fish oil with vegetable oil.

PubMed

Morais, Sofia; Pratoomyot, Jarunan; Torstensen, Bente E; Taggart, John B; Guy, Derrick R; Bell, J Gordon; Tocher, Douglas R

2011-11-01

The present study investigates the effects of genotype on responses to alternative feeds in Atlantic salmon. Microarray analysis of the liver transcriptome of two family groups, lean or fat, fed a diet containing either a fish oil (FO) or a vegetable oil (VO) blend indicated that pathways of cholesterol and lipoprotein metabolism might be differentially affected by the diet depending on the genetic background of the fish, and this was further investigated by real-time quantitative PCR, plasma and lipoprotein biochemical analysis. Results indicate a reduction in VLDL and LDL levels, with no changes in HDL, when FO is replaced by VO in the lean family group, whereas in fat fish fed FO, levels of apoB-containing lipoproteins were low and comparable with those fed VO in both family groups. Significantly lower levels of plasma TAG and LDL-TAG were measured in the fat group that was independent of diet, whereas plasma cholesterol was significantly higher in fish fed the FO diet in both groups. Hepatic expression of genes involved in cholesterol homeostasis, β-oxidation and lipoprotein metabolism showed relatively subtle changes. A significantly lower expression of genes considered anti-atherogenic in mammals (ATP-binding cassette transporter A1, apoAI, scavenger receptor class B type 1, lipoprotein lipase (LPL)b (TC67836) and LPLc (TC84899)) was found in lean fish, compared with fat fish, when fed VO. Furthermore, the lean family group appeared to show a greater response to diet composition in the cholesterol biosynthesis pathway, mediated by sterol-responsive element-binding protein 2. Finally, the presence of three different transcripts for LPL, with differential patterns of nutritional regulation, was demonstrated.

Transcriptome-wide identification, molecular evolution and expression analysis of Toll-like receptor family in a Tibet fish, Gymnocypris przewalskii.

PubMed

Tong, Chao; Lin, Yaqiu; Zhang, Cunfang; Shi, Jianquan; Qi, Hongfang; Zhao, Kai

2015-10-01

Toll-like receptors (TLR) are key components of innate immunity that play significant roles in immune defense against pathogens invasion. Recent frequent outbreaks of the "white spot disease" caused by parasitic infection in farmed Tibetan fishes had resulted in great economic losses. However, to our knowledge, the roles of TLRs in mediating immune response to parasitic infection in Tibetan fishes remain to be determined. Here, we performed data-mining on a widely-farmed Tibetan fish (Gymnocypris przewalskii or Gp) transcriptome to determine the genetic variation and expression pattern of TLRs. We totally obtained 14 GpTLRs and identified 5 with a complete coding sequence. Phylogenetic analysis verified their identities and supported the classification of TLRs into six families as in other vertebrates. The TLR family motifs, such as leucine rich repeat (LRR) and Toll/interleukin (IL)-1 receptor (TIR) domain, are conserved in GpTLR1-5. Selective pressure test demonstrated that all known GpTLRs are under purifying selection, except GpTLR4 underwent positive selection. Further, site model analysis suggested that 11 positively selected sites are found in LRR domain of GpTLR4. Three positively selected sites are located on outside surface of TLR4 3D structure, indicating that function of GpTLR4 may be affected. Tissue specific expression analysis showed all GpTLRs are present in gill, head-kidney and spleen but the relative abundance varied among tissues. In response to parasite Ichthyophthirius multifiliis infection, 5 GpTLR (GpTLR1, -2, -4, -9 and -20) expressions were induced. Intriguingly, GpTLR4 was significantly up-regulated in gills, while GpTLR19 and GpTLR21 unexpectedly showed no any change. In summary, these results revealed the first genomic resources of TLR family and several parasitic infection responsive TLRs in Tibetan fish. These findings provide key information for future studies aiming to understand the molecular mechanisms underlying the immune response to pathogen invasion in Tibetan fishes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differential gene expression associated with dietary methylmercury (MeHg) exposure in rainbow trout (Oncorhynchus mykiss) and zebrafish (Danio rerio)

PubMed Central

Liu, Qing; Basu, Niladri; Goetz, Giles; Jiang, Nan; Hutz, Reinhold J.; Tonellato, Peter J.; Carvan, Michael J.

2013-01-01

The objective of this study was to identify and evaluate conserved biomarkers that could be used in most species of teleost fish at most life-stages. We investigated the effects of sublethal methylmercury (MeHg) exposure on developing rainbow trout and zebrafish. Juvenile rainbow trout and young adult zebrafish were fed food with MeHg added at 0, 0.5, 5 and 50 ppm. Atomic absorption spectrometry was applied to measure whole body total Hg levels, and pathologic analysis was performed to identify MeHg-induced toxicity. Fish at six weeks were sampled from each group for microarray analysis using RNA from whole fish. MeHg-exposed trout and zebrafish did not show overt signs of toxicity or pathology, nor were significant differences seen in mortality, length, mass, or condition factor. The accumulation of MeHg in trout and zebrafish exhibited dose- and time-dependent patterns during six weeks, and zebrafish exhibited greater assimilation of total Hg than rainbow trout. The dysregulated genes in MeHg-treated fish have multiple functional annotations, such as iron ion homeostasis, glutathione transferase activity, regulation of muscle contraction, troponin I binding and calcium-dependent protein binding. Genes were selected as biomarker candidates based on their microarray data and their expression was evaluated by QPCR. Unfortunately, these genes are not good consistent biomarkers for both rainbow trout and zebrafish from QPCR evaluation using individual fish. Our conclusion is that biomarker analysis for aquatic toxicant assessment using fish needs to be based on tissue-, sex- and species-specific consideration. PMID:23529582

Sleep–wake regulation and hypocretin–melatonin interaction in zebrafish

PubMed Central

Appelbaum, Lior; Wang, Gordon X.; Maro, Geraldine S.; Mori, Rotem; Tovin, Adi; Marin, Wilfredo; Yokogawa, Tohei; Kawakami, Koichi; Smith, Stephen J.; Gothilf, Yoav; Mignot, Emmanuel; Mourrain, Philippe

2009-01-01

In mammals, hypocretin/orexin (HCRT) neuropeptides are important sleep–wake regulators and HCRT deficiency causes narcolepsy. In addition to fragmented wakefulness, narcoleptic mammals also display sleep fragmentation, a less understood phenotype recapitulated in the zebrafish HCRT receptor mutant (hcrtr−/−). We therefore used zebrafish to study the potential mediators of HCRT-mediated sleep consolidation. Similar to mammals, zebrafish HCRT neurons express vesicular glutamate transporters indicating conservation of the excitatory phenotype. Visualization of the entire HCRT circuit in zebrafish stably expressing hcrt:EGFP revealed parallels with established mammalian HCRT neuroanatomy, including projections to the pineal gland, where hcrtr mRNA is expressed. As pineal-produced melatonin is a major sleep-inducing hormone in zebrafish, we further studied how the HCRT and melatonin systems interact functionally. mRNA level of arylalkylamine-N-acetyltransferase (AANAT2), a key enzyme of melatonin synthesis, is reduced in hcrtr−/− pineal gland during the night. Moreover, HCRT perfusion of cultured zebrafish pineal glands induces melatonin release. Together these data indicate that HCRT can modulate melatonin production at night. Furthermore, hcrtr−/− fish are hypersensitive to melatonin, but not other hypnotic compounds. Subthreshold doses of melatonin increased the amount of sleep and consolidated sleep in hcrtr−/− fish, but not in the wild-type siblings. These results demonstrate the existence of a functional HCRT neurons-pineal gland circuit able to modulate melatonin production and sleep consolidation. PMID:19966231

UVB-induced gene expression in the skin of Xiphophorus maculatus Jp 163 B☆

PubMed Central

Yang, Kuan; Boswell, Mikki; Walter, Dylan J.; Downs, Kevin P.; Gaston-Pravia, Kimberly; Garcia, Tzintzuni; Shen, Yingjia; Mitchell, David L.; Walter, Ronald B.

2014-01-01

Xiphophorus fish and interspecies hybrids represent long-standing models to study the genetics underlying spontaneous and induced tumorigenesis. The recent release of the Xiphophorus maculatus genome sequence will allow global genetic regulation studies of genes involved in the inherited susceptibility to UVB-induced melanoma within select backcross hybrids. As a first step toward this goal, we report results of an RNA-Seq approach to identify genes and pathways showing modulated transcription within the skin of X. maculatus Jp 163 B upon UVB exposure. X. maculatus Jp 163 B were exposed to various doses of UVB followed by RNA-Seq analysis at each dose to investigate overall gene expression in each sample. A total of 357 genes with a minimum expression change of 4-fold (p-adj < 0.05) were identified as responsive to UVB. The molecular genetic response of Xiphophorus skin to UVB exposure permitted assessment of; (1) the basal expression level of each transcript for each skin sample, (2) the changes in expression levels for each gene in the transcriptome upon exposure to increasing doses of UVB, and (3) clusters of genes that exhibit similar patterns of change in expression upon UVB exposure. These data provide a foundation for understanding the molecular genetic response of fish skin to UVB exposure. PMID:24556253

9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for the...

9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for the...

9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for the...

9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

Code of Federal Regulations, 2010 CFR

2010-01-01

... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for the...

An in vivo analysis of Cr6+ induced biochemical, genotoxicological and transcriptional profiling of genes related to oxidative stress, DNA damage and apoptosis in liver of fish, Channa punctatus (Bloch, 1793).

PubMed

Awasthi, Yashika; Ratn, Arun; Prasad, Rajesh; Kumar, Manoj; Trivedi, Sunil P

2018-07-01

Present study was designed to assess the hexavalent chromium (Cr 6+ ) mediated oxidative stress that induces DNA damage and apoptosis in adult fish, Channa punctatus (35 ± 3.0 g; 14.5 ± 1.0 cm; Actinopterygii). Fishes were maintained in three groups for 15, 30 and 45 d of exposure periods. They were treated with 5% (Group T1) and 10% (Group T2) of 96 h-LC 50 of chromium trioxide (Cr 6+ ). Controls were run for the similar duration. A significant (p < 0.05) increment in the activities of antioxidant enzymes, SOD and CAT in liver tissues of the exposed fish evinces the persistence of oxidative stress. A significant (p < 0.05) increase in induction of micronuclei (MN) coupled with transcriptional responses of target genes related to antioxidant enzymes, DNA damage and apoptosis (sod, cat, gsr, nox-1, p53, bax, bcl-2, apaf-1 and casp3a) establishes the impact of oxidative stress due to in vivo, Cr 6+ accumulation in liver as compared to control (0 mg/L), in a dose and exposure-dependent manner. Initially, the increased level of reactive oxygen species (ROS) in liver coincided with that of enhanced mRNA expression of antioxidant enzymes, sod, cat, gsr and nox-1 but, later, the overproduction of ROS, after 45 d of exposure of Cr 6+ , resulted in a significant (p < 0.05) up-regulation of p53. Our findings also unveil that the up-regulation of bax, apaf-1 and casp3a and down-regulation of bcl-2 are associated with Cr 6+ -induced oxidative stress mediated-apoptosis in liver of test fish. Aforesaid molecular markers can, thus, be efficiently utilized for bio-monitoring of aquatic regimes and conservation of fish biodiversity. Copyright © 2018 Elsevier B.V. All rights reserved.

Gene expression patterns during the larval development of European sea bass (dicentrarchus labrax) by microarray analysis.

PubMed

Darias, M J; Zambonino-Infante, J L; Hugot, K; Cahu, C L; Mazurais, D

2008-01-01

During the larval period, marine teleosts undergo very fast growth and dramatic changes in morphology, metabolism, and behavior to accomplish their metamorphosis into juvenile fish. Regulation of gene expression is widely thought to be a key mechanism underlying the management of the biological processes required for harmonious development over this phase of life. To provide an overall analysis of gene expression in the whole body during sea bass larval development, we monitored the expression of 6,626 distinct genes at 10 different points in time between 7 and 43 days post-hatching (dph) by using heterologous hybridization of a rainbow trout cDNA microarray. The differentially expressed genes (n = 485) could be grouped into two categories: genes that were generally up-expressed early, between 7 and 23 dph, and genes up-expressed between 25 and 43 dph. Interestingly, among the genes regulated during the larval period, those related to organogenesis, energy pathways, biosynthesis, and digestion were over-represented compared with total set of analyzed genes. We discuss the quantitative regulation of whole-body contents of these specific transcripts with regard to the ontogenesis and maturation of essential functions that take place over larval development. Our study is the first utilization of a transcriptomic approach in sea bass and reveals dynamic changes in gene expression patterns in relation to marine finfish larval development.

Development of a transgenic zebrafish model expressing GFP in the notochord, somite and liver directed by the hfe2 gene promoter.

PubMed

Bian, Yue-Hong; Xu, Cheng; Li, Junling; Xu, Jin; Zhang, Hongwei; Du, Shao Jun

2011-08-01

Hemojuvelin, also known as RGMc, is encoded by hfe2 gene that plays an important role in iron homeostasis. hfe2 is specifically expressed in the notochord, developing somite and skeletal muscles during development. The molecular regulation of hfe2 expression is, however, not clear. We reported here the characterization of hfe2 gene expression and the regulation of its tissue-specific expression in zebrafish embryos. We demonstrated that the 6 kb 5'-flanking sequence upstream of the ATG start codon in the zebrafish hfe2 gene could direct GFP specific expression in the notochord, somites, and skeletal muscle of zebrafish embryos, recapitulating the expression pattern of the endogenous gene. However, the Tg(hfe2:gfp) transgene is also expressed in the liver of fish embryos, which did not mimic the expression of the endogenous hfe2 at the early stage. Nevertheless, the Tg(hfe2:gfp) transgenic zebrafish provides a useful model to study liver development. Treating Tg(hfe2:gfp) transgenic zebrafish embryos with valproic acid, a liver development inhibitor, significantly inhibited GFP expression in zebrafish. Together, these data indicate that the tissue specific expression of hfe2 in the notochord, somites and muscles is regulated by regulatory elements within the 6 kb 5'-flanking sequence of the hfe2 gene. Moreover, the Tg(hfe2:gfp) transgenic zebrafish line provides a useful model system for analyzing liver development in zebrafish.

Molecular characterisation and expression of parathyroid hormone-related protein in the caudal neurosecretory system of the euryhaline flounder, Platichthys flesus.

PubMed

Lu, Weiqun; Jin, Yingying; Xu, Jinling; Greenwood, Michael P; Balment, Richard J

2017-08-01

Parathyroid hormone-related protein (PTHrP) is a hypercalcemic factor in fish, but the source of circulating PTHrP remains unclear. In this study investigation of the caudal neurosecretory system (CNSS), considered one of major sources of PTHrP in fish, provided valuable insights into this regulatory system. We report pthrpa and pthrpb gene cloning, characterization, expression, and responses to low salinity and hypocalcemia challenge in flounder. The pthrpa and pthrpb precursors, isolated from a European flounder CNSS library, consist of 166 and 192 amino acid residues, respectively, with an overall homology of approximately 59.2%. Both precursors contain a signal peptide and a mature peptide with cleavage and amidation sites. The flounder PTHrPA and PTHrPB peptides share only 41% sequence identity with human PTHrPA. Quantitative PCR analysis demonstrated that the bone and bladder, are respectively major sites of pthrpa and pthrpb expression in flounder. Urophysectomy confirmed the CNSS as a likely contributor to circulating PTHrP peptides. There were no significant differences in CNSS pthrpa and pthrpb mRNA expression or plasma PTHrP levels between seawater (SW) and freshwater (FW)-adapted fish, though plasma total calcium concentrations were higher in FW animals. The intraperitonial administration of EGTA rapidly induced hypocalcemia and concomitant elevation in plasma PTHrP accompanied by increases in both pthrpa and pthrpb expression in the CNSS. Together, these findings support an evolutionary conserved role for PTHrP in the endocrine regulation of calcium. Copyright © 2017 Elsevier Inc. All rights reserved.

In vitro effects of virgin microplastics on fish head-kidney leucocyte activities.

PubMed

Espinosa, Cristóbal; García Beltrán, José María; Esteban, María Angeles; Cuesta, Alberto

2018-04-01

Microplastics are well-documented pollutants in the marine environment that result from production or fragmentation of larger plastic items. The knowledge about the direct effects of microplastics on immunity, including fish, is still very limited. We investigated the in vitro effects of microplastics [polyvinylchloride (PVC) and polyethylene (PE)] on gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) head-kidney leucocytes (HKLs). After 1 and 24 h of exposure of HKLs with 0 (control), 1, 10 and 100 mg mL -1 MPs in a rotatory system, cell viability, innate immune parameters (phagocytic, respiratory burst and peroxidase activities) and the expression of genes related to inflammation (il1b), oxidative stress (nrf2, prdx3), metabolism of xenobiotics (cyp1a1, mta) and cell apoptosis (casp3) were studied. Microplastics failed to affect the cell viability of HKLs. In addition, they provoke very few significant effects on the main cellular innate immune activities, as decrease on phagocytosis or increase in the respiratory burst of HKLs with the highest dose of microplastics tested. Furthermore, microplastics failed to affect the expression of the selected genes on sea bass or seabream, except the nrf2 which was up-regulated in seabream HKLs incubated with the highest doses. Present results seem to suggest that continue exposure of fish to PVC or PE microplastics could impair fish immune parameters probably due to the oxidative stress produced in the fish leucocytes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thyroid hormone actions on male reproductive system of teleost fish.

PubMed

Tovo-Neto, Aldo; da Silva Rodrigues, Maira; Habibi, Hamid R; Nóbrega, Rafael Henrique

2018-04-17

Thyroid hormones (THs) play important roles in the regulation of many biological processes of vertebrates, such as growth, metabolism, morphogenesis and reproduction. An increasing number of studies have been focused on the involvement of THs in the male reproductive system of vertebrates, in particular of fish. Therefore, this mini-review aims to summarize the main findings on THs role in male reproductive system of fish, focusing on sex differentiation, testicular development and spermatogenesis. The existing data in the literature have demonstrated that THs exert their roles at the different levels of the hypothalamic-pituitary-gonadal (HPG) axis. In general a positive correlation has been shown between THs and fish reproductive status; where THs are associated with testicular development, growth and maturation. Recently, the molecular mechanisms underlying the role of THs in spermatogenesis have been unraveled in zebrafish testis. THs promote germ cell proliferation and differentiation by increasing a stimulatory growth factor of spermatogenesis produced by Sertoli cells. In addition, THs enhanced the gonadotropin-induced androgen release in zebrafish testis. Next to their functions in the adult testis, THs are involved in the gonadal sex differentiation through modulating sex-related gene expression, and testicular development via regulation of Sertoli cell proliferation. In conclusion, this mini-review showed that THs modulate the male reproductive system during the different life stages of fish. The physiological and molecular mechanisms showed a link between the thyroid and reproduction, suggesting a possibly co-evolution and interdependence of these two systems. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of guava leaves on the growth performance and cytokine gene expression of Labeo rohita and its susceptibility to Aeromonas hydrophila infection.

PubMed

Giri, Sib Sankar; Sen, Shib Sankar; Chi, Cheng; Kim, Hyoun Joong; Yun, Saekil; Park, Se Chang; Sukumaran, V

2015-10-01

The present study aimed to evaluate the effects of Psidium guajava L. (guava) leaves on the growth and immune response of the fish species Labeo rohita and its susceptibility to Aeromonas hydrophila infection. Diets containing five different concentrations of guava leaves (0% [basal diet], 0.1% [G1], 0.5% [G2], 1% [G3], and 1.5% [G4]) were fed to fish (average weight: 11.1 g) for 60 days. Various growth and immune parameters were examined 60 days post-feeding. Fish were challenged with A. hydrophila at the end of the trial, and mortalities were recorded over 15 days post-infection. We found that growth parameters such as percent weight gain (657.61 ± 9.74) and specific growth rate (3.37 ± 0.021) were significantly higher in G2 group than in the control (P < 0.05). Among the immune parameters examined, lysozyme levels (79.5 ± 5.1 U mL(-1)), leukocyte phagocytic activity (52 ± 4.3%), and alternative complement pathway activity (ACP) (186.1 ± 8.3 U mL(-1)) were significantly high (P < 0.05) in G2 fed group; there was, however, no significant effect of guava leaves at any concentration on plasma IgM level. Of the cytokine-related genes examined, interleukin-1beta (IL-1β) and tumour necrosis factor-alpha (TNF-α) were up-regulated in the head-kidney, intestine, and hepatopancreas of fish fed experimental diets, and expression was significantly higher in G2 and G3 than in the control group. In contrast, gene expression of IL-10, transforming growth factor-beta (TGF-β), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and transcription factor nuclear factor-κB (NF-κB) were down-regulated in the treatment groups. Moreover, fish fed the G2 diet exhibited a significantly higher post-challenge survival rate (66.66%). Collectively, these results suggest that dietary supplementation with guava leaves (at 0.5% concentration) could promote growth performance and strengthen immunity of L. rohita. Guava leaves therefore represent a promising feed additive for carps in aquaculture. Copyright © 2015 Elsevier Ltd. All rights reserved.

Long-chain polyunsaturated fatty acid biosynthesis in the euryhaline herbivorous teleost Scatophagus argus: Functional characterization, tissue expression and nutritional regulation of two fatty acyl elongases.

PubMed

Xie, Dizhi; Chen, Fang; Lin, Siyuan; You, Cuihong; Wang, Shuqi; Zhang, Qinghao; Monroig, Óscar; Tocher, Douglas R; Li, Yuanyou

2016-08-01

Both the spotted scat Scatophagus argus and rabbitfish Siganus canaliculatus belong to the few cultured herbivorous marine teleost, however, their fatty acyl desaturase (Fad) system involved in long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis is different. The S. argus has a △6 Fad, while the rabbitfish has △4 and △6/△5 Fads, which were the first report in vertebrate and marine teleost, respectively. In order to compare the characteristics of elongases of very long-chain fatty acids (Elovl) between them, two Elovl cDNAs were cloned from S. argus in the present study. One has 885bp of open read fragment (ORF) encoding a protein with 294 amino acid (aa) showing Elovl5 activity functionally characterized by heterologous expression in yeast, which was primarily active for the elongation of C18 and C20 PUFAs. The other has 915bp of ORF coding for a 305 aa protein showing Elovl4 activity, which was more efficient in the elongation of C20 and C22 PUFAs. Tissue distribution analyses by RT-PCR showed that elovl5 was highly expressed in the liver compared to other tissues determined, whereas elovl4 transcripts were only detected in the eye. The expression of elovl5 and elovl4 were significantly affected by dietary fatty acid composition, with highest expression of mRNA in the liver and eye of fish fed a diet with an 18:3n-3/18:2n-6 ratio of 1.7:1. These results indicated that the S. argus has a similar Elovl system in the LC-PUFA biosynthetic pathway to that of rabbitfish although their Fad system was different, suggesting that the diversification of fish LC-PUFA biosynthesis specificities is more associated with its Fad system. These new insights expand our knowledge and understanding of the molecular basis and regulation of LC-PUFA biosynthesis in fish. Copyright © 2016 Elsevier Inc. All rights reserved.

A comparison of gene transcription profiles of domesticated and wild Atlantic salmon (Salmo salar L.) at early life stages, reared under controlled conditions.

PubMed

Bicskei, Beatrix; Bron, James E; Glover, Kevin A; Taggart, John B

2014-10-09

Atlantic salmon have been subject to domestication for approximately ten generations, beginning in the early 1970s. This process of artificial selection will have created various genetic differences between wild and farmed stocks. Each year, hundreds of thousands of farmed fish escape into the wild. These escapees may interbreed with wild conspecifics raising concerns for both the fish-farming industry and fisheries managers. Thus, a better understanding of the interactions between domesticated and wild salmon is essential to the continued sustainability of the aquaculture industry and to the maintenance of healthy wild stocks. We compared the transcriptomes of a wild Norwegian Atlantic salmon population (Figgjo) and a Norwegian farmed strain (Mowi) at two life stages: yolk sac fry and post first-feeding fry. The analysis employed 44 k oligo-microarrays to analyse gene expression of 36 farmed, wild and hybrid (farmed dam x wild sire) individuals reared under identical hatchery conditions. Although some of the transcriptional differences detected overlapped between sampling points, our results highlighted the importance of studying various life stages. Compared to the wild population, the Mowi strain displayed up-regulation in mRNA translation-related and down regulation in nervous and immune system -related pathways in the sac fry, whereas up-regulation of digestive and endocrine activities, carbohydrate, energy, amino acid and lipid metabolism and down-regulation of environmental information processing and immune system pathways were evident in the feeding fry. Differentially regulated pathways that were common among life stages generally belonged to environmental information processing and immune system functional groups. In addition, we found indications of strong maternal effects, reinforcing the importance of including reciprocal hybrids in the analysis. In agreement with previous studies we showed that domestication has caused changes in the transcriptome of wild Atlantic salmon and that many of the affected pathways are life-stage specific We highlighted the importance of reciprocal hybrids to the deconvolution of maternal/paternal effects and our data support the view that the genetic architecture of the strains studied highly influences the genes differentially expressed between wild and domesticated fish.

Differential protein expression in alligator leukocytes in response to bacterial lipopolysaccharide injection.

PubMed

Merchant, Mark; Kinney, Clint; Sanders, Paige

2009-12-01

Blood was collected from three juvenile alligators (Alligator mississippiensis) before, and again 24h after, injection with bacterial lipopolysaccharide (LPS). The leukocytes were collected from both samples, and the proteins were extracted. Each group of proteins was labeled with a different fluorescent dye and the differences in protein expression were analyzed by two dimensional differential in-gel expressions (2D-DIGE). The proteins which appeared to be increased or decreased by treatment with LPS were selected and analyzed by MALDI-TOF to determine mass and LC-MS/MS to acquire the partial protein sequences. The peptide sequences were compared to the NCBI protein sequence database to determine homology with other sequences from other species. Several proteins of interest appeared to be increased upon LPS stimulation. Proteins with homology to human transgelin-2, fish glucose-6-phosphate dehydrogenase, amphibian α-enolase, alligator lactate dehydrogenase, fish ubiquitin-activating enzyme, and fungal β-tubulin were also increased after LPS injection. Proteins with homology to fish vimentin 4, murine heterogeneous nuclear ribonucleoprotein A3, and avian calreticulin were found to be decreased in response to LPS. In addition, five proteins, four of which were up-regulated (827, 560, 512, and 650%) and one that exhibited repressed expression (307%), did not show homology to any protein in the database, and thus may represent newly discovered proteins. We are using this biochemical approach to isolate and characterize alligator proteins with potential relevant immune function.

Generation and characterization of gsuα:EGFP transgenic zebrafish for evaluating endocrine-disrupting effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Xiaoxia; University of Chinese Academy of Sciences, Beijing; Chen, Xiaowen

The glycoprotein subunit α (gsuα) gene encodes the shared α subunit of the three pituitary heterodimeric glycoprotein hormones: follicle-stimulating hormone β (Fshβ), luteinizing hormone β (Lhβ) and thyroid stimulating hormone β (Tshβ). In our current study, we identified and characterized the promoter region of zebrafish gsuα and generated a stable gsuα:EGFP transgenic line, which recapitulated the endogenous gsuα expression in the early developing pituitary gland. A relatively conserved regulatory element set is presented in the promoter regions of zebrafish and three other known mammalian gsuα promoters. Our results also demonstrated that the expression patterns of the gsuα:EGFP transgene were allmore » identical to those expression patterns of the endogenous gsuα expression in the pituitary tissue when our transgenic fish were treated with various endocrine chemicals, including forskolin (FSK), SP600125, trichostatin A (TSA), KClO{sub 4}, dexamethasone (Dex), β-estradiol and progesterone. Thus, this gsuα:EGFP transgenic fish reporter line provides another valuable tool for investigating the lineage development of gsuα-expressing gonadotrophins and the coordinated regulation of various glycoprotein hormone subunit genes. These reporter fish can serve as a novel platform to perform screenings of endocrine-disrupting chemicals (EDCs) in vivo as well. - Highlights: • Identification of the promoter of zebrafish glycoprotein subunit α (gsuα) gene • Generation of stable transmission gsuα:EGFP transgenic zebrafish reporter • Demonstration of the recapitulation of the gsuα:EGFP and endogenous gsuα expression • Suggestion of the gsuα:EGFP transgenic zebrafish as a novel platform for EDC study.« less

Actions of sex steroids on kisspeptin expression and other reproduction-related genes in the brain of the teleost fish European sea bass.

PubMed

Alvarado, M V; Servili, A; Molés, G; Gueguen, M M; Carrillo, M; Kah, O; Felip, A

2016-11-01

Kisspeptins are well known as mediators of the coordinated communication between the brain-pituitary axis and the gonads in many vertebrates. To test the hypothesis that gonadal steroids regulate kiss1 and kiss2 mRNA expression in European sea bass (a teleost fish), we examined the brains of gonad-intact (control) and castrated animals, as well as castrated males (GDX) and ovariectomized females (OVX) that received testosterone (T) and estradiol (E 2 ) replacement, respectively, during recrudescence. In GDX males, low expression of kiss1 mRNA is observed by in situ hybridization in the caudal hypothalamus (CH) and the mediobasal hypothalamus (MBH), although hypothalamic changes in kiss1 mRNA levels were not statistically different among the groups, as revealed by real-time PCR. However, T strongly decreased kiss2 expression levels in the hypothalamus, which was documented in the MBH and the nucleus of the lateral recess (NRLd) in GDX T-treated sea bass males. Conversely, it appears that E 2 evokes low kiss1 mRNA in the CH, while there were cells expressing kiss2 in the MBH and NRLd in these OVX females. These results demonstrate that kisspeptin neurons are presumably sensitive to the feedback actions of sex steroids in the sea bass, suggesting that the MBH represents a major site for sex steroid actions on kisspeptins in this species. Also, recent data provide evidence that both positive and negative actions occur in key factors involved in sea bass reproductive function, including changes in the expression of gnrh-1/gonadotropin, cyp19b, er and ar genes and sex steroid and gonadotropin plasma levels in this teleost fish. © 2016. Published by The Company of Biologists Ltd.

The expression and function of hsp30-like small heat shock protein genes in amphibians, birds, fish, and reptiles.

PubMed

Heikkila, John J

2017-01-01

Small heat shock proteins (sHSPs) are a superfamily of molecular chaperones with important roles in protein homeostasis and other cellular functions. Amphibians, reptiles, fish and birds have a shsp gene called hsp30, which was also referred to as hspb11 or hsp25 in some fish and bird species. Hsp30 genes, which are not found in mammals, are transcribed in response to heat shock or other stresses by means of the heat shock factor that is activated in response to an accumulation of unfolded protein. Amino acid sequence analysis revealed that representative HSP30s from different classes of non-mammalian vertebrates were distinct from other sHSPs including HSPB1/HSP27. Studies with amphibian and fish recombinant HSP30 determined that they were molecular chaperones since they inhibited heat- or chemically-induced aggregation of unfolded protein. During non-mammalian vertebrate development, hsp30 genes were differentially expressed in selected tissues. Also, heat shock-induced stage-specific expression of hsp30 genes in frog embryos was regulated at the level of chromatin structure. In adults and/or tissue culture cells, hsp30 gene expression was induced by heat shock, arsenite, cadmium or proteasomal inhibitors, all of which enhanced the production of unfolded/damaged protein. Finally, immunocytochemical analysis of frog and chicken tissue culture cells revealed that proteotoxic stress-induced HSP30 accumulation co-localized with aggresome-like inclusion bodies. The congregation of damaged protein in aggresomes minimizes the toxic effect of aggregated protein dispersed throughout the cell. The current availability of probes to detect the presence of hsp30 mRNA or encoded protein has resulted in the increased use of hsp30 gene expression as a marker of proteotoxic stress in non-mammalian vertebrates. Copyright © 2016 Elsevier Inc. All rights reserved.

Gene-expression analysis of hair cell regeneration in the zebrafish lateral line

PubMed Central

Jiang, Linjia; Romero-Carvajal, Andres; Haug, Jeff S.; Seidel, Christopher W.; Piotrowski, Tatjana

2014-01-01

Deafness caused by the terminal loss of inner ear hair cells is one of the most common sensory diseases. However, nonmammalian animals (e.g., birds, amphibians, and fish) regenerate damaged hair cells. To understand better the reasons underpinning such disparities in regeneration among vertebrates, we set out to define at high resolution the changes in gene expression associated with the regeneration of hair cells in the zebrafish lateral line. We performed RNA-Seq analyses on regenerating support cells purified by FACS. The resulting expression data were subjected to pathway enrichment analyses, and the differentially expressed genes were validated in vivo via whole-mount in situ hybridizations. We discovered that cell cycle regulators are expressed hours before the activation of Wnt/β-catenin signaling following hair cell death. We propose that Wnt/β-catenin signaling is not involved in regulating the onset of proliferation but governs proliferation at later stages of regeneration. In addition, and in marked contrast to mammals, our data clearly indicate that the Notch pathway is significantly down-regulated shortly after injury, thus uncovering a key difference between the zebrafish and mammalian responses to hair cell injury. Taken together, our findings lay the foundation for identifying differences in signaling pathway regulation that could be exploited as potential therapeutic targets to promote either sensory epithelium or hair cell regeneration in mammals. PMID:24706903

Species-specific considerations in using the fish embryo test as an alternative to identify endocrine disruption.

PubMed

Schiller, Viktoria; Zhang, Xiaowei; Hecker, Markus; Schäfers, Christoph; Fischer, Rainer; Fenske, Martina

2014-10-01

A number of regulations have been implemented that aim to control the release of potentially adverse endocrine disrupters into the aquatic environment based on evidence from laboratory studies. Currently, such studies rely on testing approaches with adult fish because reliable alternatives have not been validated so far. Fish embryo tests have been proposed as such an alternative, and here we compared two species (medaka and zebrafish) to determine their suitability for the assessment of substances with estrogenic and anti-androgenic activity. Changes in gene expression (in here the phrase gene expression is used synonymously to gene transcription, although it is acknowledged that gene expression is additionally regulated, e.g., by translation and protein stability) patterns between the two species were compared in short term embryo exposure tests (medaka: 7-day post fertilization [dpf]; zebrafish: 48 and 96h post fertilization [hpf]) by using relative quantitative real-time RT-PCR. The tested genes were related to the hypothalamic-gonadal-axis and early steroidogenesis. Test chemicals included 17α-ethinylestradiol and flutamide as estrogenic and anti-androgenic reference compounds, respectively, as well as five additional substances with endocrine activities, namely bisphenol A, genistein, prochloraz, linuron and propanil. Estrogenic responses were comparable in 7-dpf medaka and 48/96-hpf zebrafish embryos and included transcriptional upregulation of aromatase b, vitellogenin 1 as well as steroidogenic genes, suggesting that both species reliably detected exposure to estrogenic compounds. However, anti-androgenic responses differed between the two species, with each species providing specific information concerning the mechanism of anti-androgenic disruption in fish embryos. Although small but significant changes in the expression of selected genes was observed in 48-hpf zebrafish embryos, exposure prolonged to 96hpf was necessary to obtain a response indicative of anti-androgenic activity. In contrast, for medaka clear anti-androgenic response, e.g. transcriptional downregulation of 11β-hydroxylase, 3β-hydroxysteroid-dehydrogenase, gonadotropin-releasing hormone receptor 2, was already observed at the pre-hatch stage. Together, this data suggests that medaka and zebrafish embryos would provide a beneficial alternative testing platform for endocrine disruption that involves additive information on interspecies and exposure time variability when using both species. Copyright © 2014 Elsevier B.V. All rights reserved.

Role of Bacillus subtilis VSG4-derived biosurfactant in mediating immune responses in Labeo rohita.

PubMed

Giri, Sib Sankar; Sen, Shib Sankar; Jun, Jin Woo; Sukumaran, Venkatachalam; Park, Se Chang

2016-07-01

This study aimed to isolate biosurfactant from CO2-sequestering Bacillus subtilis VSG4 and to evaluate its immunostimulatory effect in Labeo rohita fingerlings. Fish were injected intraperitoneally (i.p.) with 0.1 mL of phosphate-buffered saline (PBS) containing the water-soluble fraction of purified biosurfactant at 50 (S50), 100 (S100), 200 (S200), or 300 (S300) μg mL(-1). Fish injected with PBS served as controls. Various immunological parameters, including immune-related gene expression, were measured at 14, 21, and 28 days post administration (dpa). At 28 dpa, the fish were challenged with Aeromonas hydrophila and mortality was recorded up to 14 days. Among the immune parameters tested, lysozyme levels (36.32 ± 1.79 U mL(-1)), alternative complement pathway activity (76.26 ± 2.18 U mL(-1)), phagocytic activity (32.18 ± 0.67%), and serum bactericidal activity (73.2 ± 4.7%) were significantly higher (P < 0.05) in the S200 group at 21 dpa than in the controls. Respiratory burst activity (0.386 ± 0.008 OD630nm) was the highest in the S200 group at 28 dpa. Of the immune-related genes examined, pro-inflammatory cytokines (TNF-α and IL-1β) were significantly down-regulated in the S200 and S300 groups. Expression of anti-inflammatory cytokines (IL-10 and TGF-β) as well as IKB-α was higher (P < 0.05) in the S100‒S300 groups at 21 dpa. The expression of NF-κB p65, IKK-β, MAPKp38, and Myd88 was down-regulated in the treated groups when compared to the controls. Fish in the S200 group exhibited the highest post-challenge relative survival rate (67.88%). Collectively, these results suggest that secondary metabolite (biosurfactant) isolated from B. subtilis VSG4 at 200 μg mL(-1) can positively influence immune responses, enhance disease resistance, and stimulate immune-related gene expression in L. rohita. Copyright © 2016 Elsevier Ltd. All rights reserved.

Challenge with 17alpha-ethinylestradiol (EE2) during early development persistently impairs growth, differentiation, and local expression of IGF-I and IGF-II in immune organs of tilapia.

PubMed

Shved, Natallia; Berishvili, Giorgi; Häusermann, Eliane; D'Cotta, Helena; Baroiller, Jean-François; Eppler, Elisabeth

2009-03-01

The enormous expansion of world-wide aquaculture has led to increasing interest in the regulation of fish immune system. Estrogen has recently been shown to inhibit the endocrine (liver-derived) and autocrine/paracrine local insulin-like growth factor-I system in fish. In order to address the potential actions of estrogen on the IGF system in immune organs, tilapia were fed with 17alpha-ethinylestradiol (EE2)-enriched food from 10 to 40 days post fertilization (DPF) to induce functional feminization, an approach commonly used in aquaculture. EE2-treated and control fish were sampled at 75 and 165 DPF. The expression levels of ER-alpha, IGF-I, IGF-II and growth hormone receptor (GH-R) mRNA in spleen and head kidney were determined by real-time PCR and the expressing sites of IGF-I mRNA identified by in situ hybridisation. Ratios of spleen length and weight to body length and weight were determined. At 165 DPF, the length (4.9% vs. 7.6%) and weight (0.084% vs. 0.132%) ratios were significantly lowered in EE2-treated fish and number and size of the melanomacrophage centres were considerably reduced. At 75 DPF, both in spleen and head kidney of EE2-treated fish the expression levels of IGF-I and IGF-II mRNA were markedly diminished. The suppression was more pronounced for IGF-I (spleen: -12.071-fold; head kidney: -8.413-fold) than for IGF-II (spleen: -4.102-fold; head kidney: -1.342-fold). In agreement, clearly fewer leucocytes and macrophages in head kidney and spleen of EE2-treated fish contained IGF-I mRNA as shown by in situ hybridisation. ER-alpha mRNA expression in spleen was increased at 75 DPF but unchanged in head kidney. GH-R gene expression showed a mild upregulation at 165 DPF in both tissues. Thus, exposure to EE2 during early development affected distinctly the IGF system in tilapia immune organs. It led to lasting impairment of spleen growth and differentiation that can be attributed to an interaction of EE2 with IGF-I and, less pronouncedly, IGF-II. Especially, the impairment of spleen and melanomacrophage centres might interfere with the antigen presentation capacity of the immune system and, thus, alter susceptibility to infection.

Schizothorax prenanti corticotropin-releasing hormone (CRH): molecular cloning, tissue expression, and the function of feeding regulation.

PubMed

Wang, Tao; Zhou, Chaowei; Yuan, Dengyue; Lin, Fangjun; Chen, Hu; Wu, Hongwei; Wei, Rongbin; Xin, Zhiming; Liu, Ju; Gao, Yundi; Li, Zhiqiong

2014-10-01

Corticotropin-releasing hormone (CRH) is a potent mediator of endocrine, autonomic, behavioral, and immune responses to stress. For a better understanding of the structure and function of the CRH gene and to study its effect on feeding regulation in cyprinid fish, the cDNA of the CRH gene from the brain of Schizothorax prenanti was cloned and sequenced. The full-length CRH cDNA consisted of 1,046 bp with an open reading frame of 489 bp encoding a protein of 162 amino acids. Real-time quantitative PCR analyses revealed that CRH was widely expressed in central and peripheral tissues. In particular, high expression level of CRH was detected in brain. Furthermore, CRH mRNA expression was examined in different brain regions, especially high in hypothalamus. In addition, there was no significant change in CRH mRNA expression in fed group compared with the fasted group in the S. prenanti hypothalamus during short-term fasting. However, CRH gene expression presented significant decrease in the hypothalamus in fasted group compared with the fed group (P < 0.05) on day 7; thereafter, re-feeding could lead to a significant increase in CRH mRNA expression in fasted group on day 9. The results suggest that the CRH may play a critical role in feeding regulation in S. prenanti.

PSA-NCAM expression in the teleost optic tectum is related to ecological niche and use of vision in finding food.

PubMed

Labak, I; Pavić, V; Zjalić, M; Blažetić, S; Viljetić, B; Merdić, E; Heffer, M

2017-08-01

In this study, tangential migration and neuronal connectivity organization were analysed in the optic tectum of seven different teleosts through the expression of polysialylated neural cell adhesion molecule (PSA-NCAM) in response to ecological niche and use of vision. Reduced PSA-NCAM expression in rainbow trout Oncorhynchus mykiss optic tectum occurred in efferent layers, while in pike Esox lucius and zebrafish Danio rerio it occurred in afferent and efferent layers. Zander Sander lucioperca and European eel Anguilla anguilla had very low PSA-NCAM expression in all tectal layers except in the stratum marginale. Common carp Cyprinus carpio and wels catfish Silurus glanis had the same intensity of PSA-NCAM expression in all tectal layers. The optic tectum of all studied fishes was also a site of tangential migration with sustained PSA-NCAM and c-series ganglioside expression. Anti-c-series ganglioside immunoreactivity was observed in all tectal layers of all analysed fishes, even in layers where PSA-NCAM expression was reduced. Since the optic tectum is indispensable for visually guided prey capture, stabilization of synaptic contact and decrease of neurogenesis and tangential migration in the visual map are an expected adjustment to ecological niche. The authors hypothesize that this stabilization would probably be achieved by down-regulation of PSA-NCAM rather than c-series of ganglioside. © 2017 The Fisheries Society of the British Isles.

The expression of amh and amhr2 is associated with the development of gonadal tissue and sex change in the protandrous black porgy, Acanthopagrus schlegeli.

PubMed

Wu, Guan-Chung; Chiu, Po-Chia; Lyu, Ying-Syuan; Chang, Ching-Fong

2010-09-01

The protandrous black porgy, Acanthopagrus schlegeli, has a striking life cycle, with sex differentiation at the juvenile stage, mono-male development, a bisexual gonad during the first 2 yr of life, and a male-to-female sex change (with vitellogenic oocytes) at 3 yr of age. In the present study, we investigated the possible roles of amh and amhr2 in gonadal development in a nonmammalian model organism (protandrous black porgy), especially in relation to sex differentiation, testicular and ovarian growth, and sex change. Fish of various ages were treated with estradiol or an aromatase inhibitor to induce the fish to become female. Furthermore, a natural sex change (2(+)-yr-old [>2 yr and <3 yr] fish) and a nonchemical method to surgically remove one of the pair of gonads to examine the possible roles of amh in the natural sex change were conducted. We present integrative in situ hybridization, immunohistochemical, cellular, and molecular data describing these phenomena. During gonadal sex differentiation, an increase in amh and amhr2 expression was detected. Higher levels of amh and amhr2 transcripts were observed in the testicular tissue when compared to the ovarian tissue in the bisexual gonad of 1(+)-yr-old (>1 yr and <2 yr) fish. Transcripts of amh reached peak levels in November (prespermatogenesis period) and then declined to the lowest levels in January (spawning period). Chemical-induced ovarian tissue had very low amh transcript levels but high levels of amhr2. Active testes had significantly higher amh and amhr2 expression levels as compared to inactive testes. In contrast, no difference in the expression of amh and amhr2 between active and inactive ovarian tissues was found. Transcripts of amh were expressed in the somatic cells of the spermatogonia and vitellogenic oocytes, and amhr2 was expressed in the somatic cells of the spermatogonia. Transcripts of amh decreased in the testicular tissue 5 mo before occurrence of the sex change into a female. In contrast, testicular amh expression remained high if the fish remained male. Human chorionic gonadotropin regulated amh and amhr2 expression in the testicular tissue but not in the ovarian tissue. The present results suggest that amh plays important roles in early testicular and ovarian development, late ovarian growth (e.g., vitellogenic oocytes), and natural sex change in the protandrous black porgy.

Comparative Transcriptome Analysis Reveals the Genetic Basis of Skin Color Variation in Common Carp

PubMed Central

Jiang, Yanliang; Zhang, Songhao; Xu, Jian; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A.; Sun, Xiaowen; Xu, Peng

2014-01-01

Background The common carp is an important aquaculture species that is widely distributed across the world. During the long history of carp domestication, numerous carp strains with diverse skin colors have been established. Skin color is used as a visual criterion to determine the market value of carp. However, the genetic basis of common carp skin color has not been extensively studied. Methodology/Principal Findings In this study, we performed Illumina sequencing on two common carp strains: the reddish Xingguo red carp and the brownish-black Yellow River carp. A total of 435,348,868 reads were generated, resulting in 198,781 assembled contigs that were used as reference sequences. Comparisons of skin transcriptome files revealed 2,012 unigenes with significantly different expression in the two common carp strains, including 874 genes that were up-regulated in Xingguo red carp and 1,138 genes that were up-regulated in Yellow River carp. The expression patterns of 20 randomly selected differentially expressed genes were validated using quantitative RT-PCR. Gene pathway analysis of the differentially expressed genes indicated that melanin biosynthesis, along with the Wnt and MAPK signaling pathways, is highly likely to affect the skin pigmentation process. Several key genes involved in the skin pigmentation process, including TYRP1, SILV, ASIP and xCT, showed significant differences in their expression patterns between the two strains. Conclusions In this study, we conducted a comparative transcriptome analysis of Xingguo red carp and Yellow River carp skins, and we detected key genes involved in the common carp skin pigmentation process. We propose that common carp skin pigmentation depends upon at least three pathways. Understanding fish skin color genetics will facilitate future molecular selection of the fish skin colors with high market values. PMID:25255374

Comparative transcriptome analysis reveals the genetic basis of skin color variation in common carp.

PubMed

Jiang, Yanliang; Zhang, Songhao; Xu, Jian; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A; Sun, Xiaowen; Xu, Peng

2014-01-01

The common carp is an important aquaculture species that is widely distributed across the world. During the long history of carp domestication, numerous carp strains with diverse skin colors have been established. Skin color is used as a visual criterion to determine the market value of carp. However, the genetic basis of common carp skin color has not been extensively studied. In this study, we performed Illumina sequencing on two common carp strains: the reddish Xingguo red carp and the brownish-black Yellow River carp. A total of 435,348,868 reads were generated, resulting in 198,781 assembled contigs that were used as reference sequences. Comparisons of skin transcriptome files revealed 2,012 unigenes with significantly different expression in the two common carp strains, including 874 genes that were up-regulated in Xingguo red carp and 1,138 genes that were up-regulated in Yellow River carp. The expression patterns of 20 randomly selected differentially expressed genes were validated using quantitative RT-PCR. Gene pathway analysis of the differentially expressed genes indicated that melanin biosynthesis, along with the Wnt and MAPK signaling pathways, is highly likely to affect the skin pigmentation process. Several key genes involved in the skin pigmentation process, including TYRP1, SILV, ASIP and xCT, showed significant differences in their expression patterns between the two strains. In this study, we conducted a comparative transcriptome analysis of Xingguo red carp and Yellow River carp skins, and we detected key genes involved in the common carp skin pigmentation process. We propose that common carp skin pigmentation depends upon at least three pathways. Understanding fish skin color genetics will facilitate future molecular selection of the fish skin colors with high market values.

CTCF-Mediated and Pax6-Associated Gene Expression in Corneal Epithelial Cell-Specific Differentiation

PubMed Central

Tsui, Shanli; Wang, Jie; Wang, Ling; Dai, Wei; Lu, Luo

2016-01-01

Background The purpose of the study is to elicit the epigenetic mechanism involving CCCTC binding factor (CTCF)-mediated chromatin remodeling that regulates PAX6 gene interaction with differentiation-associated genes to control corneal epithelial differentiation. Methods Cell cycle progression and specific keratin expressions were measured to monitor changes of differentiation-induced primary human limbal stem/progenitor (HLS/P), human corneal epithelial (HCE) and human telomerase-immortalized corneal epithelial (HTCE) cells. PAX6-interactive and differentiation-associated genes in chromatin remodeling mediated by the epigenetic factor CTCF were detected by circular chromosome conformation capture (4C) and ChIP (Chromatin immunoprecipitation)-on-chip approaches, and verified by FISH (Fluorescent in situ hybridization). Furthermore, CTCF activities were altered by CTCF-shRNA to study the effect of CTCF on mediating interaction of Pax6 and differentiation-associated genes in corneal epithelial cell fate. Results Our results demonstrated that differentiation-induced human corneal epithelial cells expressed typical corneal epithelial characteristics including morphological changes, increased keratin12 expression and G0/G1 accumulations. Expressions of CTCF and PAX6 were suppressed and elevated following the process of differentiation, respectively. During corneal epithelial cell differentiation, differentiation-induced RCN1 and ADAM17 were found interacting with PAX6 in the process of CTCF-mediated chromatin remodeling detected by 4C and verified by ChIP-on-chip and FISH. Diminished CTCF mRNA with CTCF-shRNA in HTCE cells weakened the interaction of PAX6 gene in controlling RCN1/ADAM17 and enhanced early onset of the genes in cell differentiation. Conclusion Our results explain how epigenetic factor CTCF-mediated chromatin remodeling regulates interactions between eye-specific PAX6 and those genes that are induced/associated with cell differentiation to modulate corneal epithelial cell-specific differentiation. PMID:27583466

Skeletal muscle plasticity induced by seasonal acclimatization involves IGF1 signaling: implications in ribosomal biogenesis and protein synthesis.

PubMed

Fuentes, Eduardo N; Zuloaga, Rodrigo; Valdes, Juan Antonio; Molina, Alfredo; Alvarez, Marco

2014-10-01

One of the most fundamental biological processes in living organisms that are affected by environmental fluctuations is growth. In fish, skeletal muscle accounts for the largest proportion of body mass, and the growth of this tissue is mainly controlled by the insulin-like growth factor (IGF) system. By using the carp (Cyprinus carpio), a fish that inhabits extreme conditions during winter and summer, we assessed the skeletal muscle plasticity induced by seasonal acclimatization and the relation of IGF signaling with protein synthesis and ribosomal biogenesis. The expression of igf1 in muscle decreased during winter in comparison with summer, whereas the expression for both paralogues of igf2 did not change significantly between seasons. The expression of igf1 receptor a (igf1ra), but not of igf1rb, was down-regulated in muscle during the winter as compared to the summer. A decrease in protein contents and protein phosphorylation for IGF signaling molecules in muscle was observed in winter-acclimatized carp. This was related with a decreased expression in muscle for markers of myogenesis (myoblast determination factor (myod), myogenic factor 5 (myf5), and myogenin (myog)); protein synthesis (myosin heavy chain (mhc) and myosin light chain (mlc3 and mlc1b)); and ribosomal biogenesis (pre-rRNA and ribosomal proteins). IGF signaling, and key markers of ribosomal biogenesis, protein synthesis, and myogenesis were affected by seasonal acclimatization, with differential regulation in gene expression and signaling pathway activation observed in muscle between both seasons. This suggests that these molecules are responsible for the muscle plasticity induced by seasonal acclimatization in carp. Copyright © 2014 Elsevier Inc. All rights reserved.

ICI 182,780 has agonistic effects and synergizes with estradiol-17 beta in fish liver, but not in testis.

PubMed

Pinto, Patrícia I S; Singh, Pratap B; Condeça, João B; Teodósio, Helena R; Power, Deborah M; Canário, Adelino V M

2006-12-27

ICI 182,780 (ICI) belongs to a new class of antiestrogens developed to be pure estrogen antagonists and, in addition to its therapeutic use, it has been used to knock-out estrogen and estrogen receptor (ER) actions in several mammalian species. In the present study, the effects and mechanism of action of ICI were investigated in the teleost fish, sea bream (Sparus auratus). Three independent in vivo experiments were performed in which mature male tilapia (Oreochromis mossambicus) or sea bream received intra-peritoneal implants containing estradiol-17 beta (E2), ICI or a combination of both compounds. The effects of E2 and ICI on plasma calcium levels were measured and hepatic and testicular gene expression of the three ER subtypes, ER alpha, ER beta a and ER beta b, and the estrogen-responsive genes, vitellogenin II and choriogenin L, were analyzed by semi-quantitative RT-PCR in sea bream. E2 treatment caused an increase in calcium levels in tilapia, while ICI alone had no noticeable effect, as expected. However, pretreatment with ICI synergistically potentiated the effect of E2 on plasma calcium in both species. ICI mimicked some E2 actions in gene expression in sea bream liver upregulating ER alpha, vitellogenin II and choriogenin L, although, unlike E2, it did not downregulate ER beta a and ER beta b. In contrast, no effects of E2 or ICI alone were detected in the expression of ERs in testis, while vitellogenin II and choriogenin L were upregulated by E2 but not ICI. Finally, pretreatment with ICI had a synergistic effect on the hepatic E2 down-regulation of ER beta b, but apparently blocked the ER alpha up-regulation by E2. These results demonstrate that ICI has agonistic effects on several typical estrogenic responses in fish, but its actions are tissue-specific. The mechanisms for the ICI agonistic activity are still unknown; although the ICI induced up-regulation of ER alpha mRNA could be one of the factors contributing to the cellular response.

ICI 182,780 has agonistic effects and synergizes with estradiol-17 beta in fish liver, but not in testis

PubMed Central

Pinto, Patrícia IS; Singh, Pratap B; Condeça, João B; Teodósio, Helena R; Power, Deborah M; Canário, Adelino VM

2006-01-01

Background ICI 182,780 (ICI) belongs to a new class of antiestrogens developed to be pure estrogen antagonists and, in addition to its therapeutic use, it has been used to knock-out estrogen and estrogen receptor (ER) actions in several mammalian species. In the present study, the effects and mechanism of action of ICI were investigated in the teleost fish, sea bream (Sparus auratus). Methods Three independent in vivo experiments were performed in which mature male tilapia (Oreochromis mossambicus) or sea bream received intra-peritoneal implants containing estradiol-17 beta (E2), ICI or a combination of both compounds. The effects of E2 and ICI on plasma calcium levels were measured and hepatic and testicular gene expression of the three ER subtypes, ER alpha, ER beta a and ER beta b, and the estrogen-responsive genes, vitellogenin II and choriogenin L, were analyzed by semi-quantitative RT-PCR in sea bream. Results E2 treatment caused an increase in calcium levels in tilapia, while ICI alone had no noticeable effect, as expected. However, pretreatment with ICI synergistically potentiated the effect of E2 on plasma calcium in both species. ICI mimicked some E2 actions in gene expression in sea bream liver upregulating ER alpha, vitellogenin II and choriogenin L, although, unlike E2, it did not downregulate ER beta a and ER beta b. In contrast, no effects of E2 or ICI alone were detected in the expression of ERs in testis, while vitellogenin II and choriogenin L were upregulated by E2 but not ICI. Finally, pretreatment with ICI had a synergistic effect on the hepatic E2 down-regulation of ER beta b, but apparently blocked the ER alpha up-regulation by E2. Conclusion These results demonstrate that ICI has agonistic effects on several typical estrogenic responses in fish, but its actions are tissue-specific. The mechanisms for the ICI agonistic activity are still unknown; although the ICI induced up-regulation of ER alpha mRNA could be one of the factors contributing to the cellular response. PMID:17192186

Physical and Flavor Characteristics, Fatty Acid Profile, Antioxidant Status and Nrf2-Dependent Antioxidant Enzyme Gene Expression Changes in Young Grass Carp (Ctenopharyngodon idella) Fillets Fed Dietary Valine.

PubMed

Luo, Jian-Bo; Feng, Lin; Jiang, Wei-Dan; Liu, Yang; Wu, Pei; Jiang, Jun; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

2017-01-01

This study was conducted to examine the effects of dietary valine on the physical and flavor characteristics, fatty acid (FA) profile, antioxidant status and Nrf2-dependent antioxidant enzyme gene expression in the muscle of young grass carp (Ctenopharyngodon idella) fed increasing levels of valine (4.3, 8.0, 10.6, 13.1, 16.9 and 19.1 g/kg) for 8 weeks. Compared with the control group, the group fed valine showed improved physical characteristics of fish fillets (increased relative shear force, hydroxyproline, protein and lipid levels and decreased cathepsin B and L activities, as well as cooking loss, were observed). Moreover, valine improved the flavor of young grass carp fillets by increasing the amino acid (AA) concentration in fish muscle (increased aspartic acid, threonine, glutamine, cystine, methionine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine and valine concentrations were observed). Additionally, optimal valine supplementation increased the potential health benefits to humans by decreasing the saturated FA (C15:0 and C16:0) concentration and increasing the unsaturated FA (monounsaturated FAs (MUFAs), such as C16:1, C18:1c+t and C20:1, and polyunsaturated FAs (PUFAs), such as C18:3n-3, C20:2 and C22:6) concentration. In addition, the reduced glutathione (GSH) content and the activities of Cu/Zn superoxide dismutase (SOD1), catalase (CAT) and Selenium-dependent glutathione peroxydase (Se-GPx) increased under valine supplementation (P < 0.05). Furthermore, the SOD1, CAT and Se-GPx mRNA levels increased with dietary valine levels, possibly due to the up-regulation of NF-E2-related factor 2 (Nrf2), target of rapamycin (TOR) and ribosomal protein S6 kinase 1 (S6K1) and the down-regulation of Kelch-like-ECH-associated protein 1 (Keap1) in muscle (P < 0.05). In conclusion, valine improved the physical and flavor characteristics, FA profile, and antioxidant status and regulated the expression of the antioxidant enzyme genes Nrf2, Keap1, TOR and S6K1 in fish fillets.

Physical and Flavor Characteristics, Fatty Acid Profile, Antioxidant Status and Nrf2-Dependent Antioxidant Enzyme Gene Expression Changes in Young Grass Carp (Ctenopharyngodon idella) Fillets Fed Dietary Valine

PubMed Central

Jiang, Wei-Dan; Liu, Yang; Wu, Pei; Jiang, Jun; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

2017-01-01

This study was conducted to examine the effects of dietary valine on the physical and flavor characteristics, fatty acid (FA) profile, antioxidant status and Nrf2-dependent antioxidant enzyme gene expression in the muscle of young grass carp (Ctenopharyngodon idella) fed increasing levels of valine (4.3, 8.0, 10.6, 13.1, 16.9 and 19.1 g/kg) for 8 weeks. Compared with the control group, the group fed valine showed improved physical characteristics of fish fillets (increased relative shear force, hydroxyproline, protein and lipid levels and decreased cathepsin B and L activities, as well as cooking loss, were observed). Moreover, valine improved the flavor of young grass carp fillets by increasing the amino acid (AA) concentration in fish muscle (increased aspartic acid, threonine, glutamine, cystine, methionine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine and valine concentrations were observed). Additionally, optimal valine supplementation increased the potential health benefits to humans by decreasing the saturated FA (C15:0 and C16:0) concentration and increasing the unsaturated FA (monounsaturated FAs (MUFAs), such as C16:1, C18:1c+t and C20:1, and polyunsaturated FAs (PUFAs), such as C18:3n-3, C20:2 and C22:6) concentration. In addition, the reduced glutathione (GSH) content and the activities of Cu/Zn superoxide dismutase (SOD1), catalase (CAT) and Selenium-dependent glutathione peroxydase (Se-GPx) increased under valine supplementation (P < 0.05). Furthermore, the SOD1, CAT and Se-GPx mRNA levels increased with dietary valine levels, possibly due to the up-regulation of NF-E2-related factor 2 (Nrf2), target of rapamycin (TOR) and ribosomal protein S6 kinase 1 (S6K1) and the down-regulation of Kelch-like-ECH-associated protein 1 (Keap1) in muscle (P < 0.05). In conclusion, valine improved the physical and flavor characteristics, FA profile, and antioxidant status and regulated the expression of the antioxidant enzyme genes Nrf2, Keap1, TOR and S6K1 in fish fillets. PMID:28118364

R-spondin 3 regulates dorsoventral and anteroposterior patterning by antagonizing Wnt/β-catenin signaling in zebrafish embryos.

PubMed

Rong, Xiaozhi; Chen, Chen; Zhou, Pin; Zhou, Yumei; Li, Yun; Lu, Ling; Liu, Yunzhang; Zhou, Jianfeng; Duan, Cunming

2014-01-01

The Wnt/β-catenin or canonical Wnt signaling pathway plays fundamental roles in early development and in maintaining adult tissue homeostasis. R-spondin 3 (Rspo3) is a secreted protein that has been implicated in activating the Wnt/β-catenin signaling in amphibians and mammals. Here we report that zebrafish Rspo3 plays a negative role in regulating the zygotic Wnt/β-catenin signaling. Zebrafish Rspo3 has a unique domain structure. It contains a third furin-like (FU3) domain. This FU3 is present in other four ray-finned fish species studied but not in elephant shark. In zebrafish, rspo3 mRNA is maternally deposited and has a ubiquitous expression in early embryonic stages. After 12 hpf, its expression becomes tissue-specific. Forced expression of rspo3 promotes dorsoanterior patterning and increases the expression of dorsal and anterior marker genes. Knockdown of rspo3 increases ventral-posterior development and stimulates ventral and posterior marker genes expression. Forced expression of rspo3 abolishes exogenous Wnt3a action and reduces the endogenous Wnt signaling activity. Knockdown of rspo3 results in increased Wnt/β-catenin signaling activity. Further analyses indicate that Rspo3 does not promote maternal Wnt signaling. Human RSPO3 has similar action when tested in zebrafish embryos. These results suggest that Rspo3 regulates dorsoventral and anteroposterior patterning by negatively regulating the zygotic Wnt/β-catenin signaling in zebrafish embryos.

R-Spondin 3 Regulates Dorsoventral and Anteroposterior Patterning by Antagonizing Wnt/β-Catenin Signaling in Zebrafish Embryos

PubMed Central

Zhou, Pin; Zhou, Yumei; Li, Yun; Lu, Ling; Liu, Yunzhang; Zhou, Jianfeng; Duan, Cunming

2014-01-01

The Wnt/β-catenin or canonical Wnt signaling pathway plays fundamental roles in early development and in maintaining adult tissue homeostasis. R-spondin 3 (Rspo3) is a secreted protein that has been implicated in activating the Wnt/β-catenin signaling in amphibians and mammals. Here we report that zebrafish Rspo3 plays a negative role in regulating the zygotic Wnt/β-catenin signaling. Zebrafish Rspo3 has a unique domain structure. It contains a third furin-like (FU3) domain. This FU3 is present in other four ray-finned fish species studied but not in elephant shark. In zebrafish, rspo3 mRNA is maternally deposited and has a ubiquitous expression in early embryonic stages. After 12 hpf, its expression becomes tissue-specific. Forced expression of rspo3 promotes dorsoanterior patterning and increases the expression of dorsal and anterior marker genes. Knockdown of rspo3 increases ventral-posterior development and stimulates ventral and posterior marker genes expression. Forced expression of rspo3 abolishes exogenous Wnt3a action and reduces the endogenous Wnt signaling activity. Knockdown of rspo3 results in increased Wnt/β-catenin signaling activity. Further analyses indicate that Rspo3 does not promote maternal Wnt signaling. Human RSPO3 has similar action when tested in zebrafish embryos. These results suggest that Rspo3 regulates dorsoventral and anteroposterior patterning by negatively regulating the zygotic Wnt/β-catenin signaling in zebrafish embryos. PMID:24918770

Viral hemorrhagic septicaemia virus (VHSV) up-regulates the cytotoxic activity and the perforin/granzyme pathway in the rainbow trout RTS11 cell line.

PubMed

Ordás, M C; Cuesta, A; Mercado, L; Bols, N C; Tafalla, C

2011-08-01

A survey of immune-relevant genes that might be up-regulated in response to viral hemorrhagic septicaemia virus (VHSV) in the rainbow trout monocyte-macrophage cell line, RTS11, unexpectedly revealed an increased expression of perforin (PRF) and granzyme (GRZ) genes, which represent components of the major cytotoxic pathway. The natural killer-enhancing factor (NKEF), also known to modulate cytotoxic activity, was up-regulated at the gene but strikingly down-regulated at protein level. The expression of these genes was not affected in head kidney leukocytes (HKLs) infected with VHSV, leading us to evaluate the potential cytotoxic activity of RTS11 and HKLs. For the first time, the cytotoxic activity of RTS11 against xenogeneic targets has been demonstrated, although this was modest relative to HKLs. Yet the activity in RTS11 was significantly increased by VHSV, as in HKLs. This cytotoxic activity elicited by viral infection appeared to require viral gene expression because inactivated VHSV failed to increase RTS11 cytotoxic activity. As for other immune functions, RTS11 cells provide a model for further studying cytotoxic activities of fish monocyte-macrophages. Copyright © 2011 Elsevier Ltd. All rights reserved.

Development of the Astyanax mexicanus circadian clock and non-visual light responses.

PubMed

Frøland Steindal, Inga A; Beale, Andrew D; Yamamoto, Yoshiyuki; Whitmore, David

2018-06-23

Most animals and plants live on the planet exposed to periods of rhythmic light and dark. As such, they have evolved endogenous circadian clocks to regulate their physiology rhythmically, and non-visual light detection mechanisms to set the clock to the environmental light-dark cycle. In the case of fish, circadian pacemakers are not only present in the majority of tissues and cells, but these tissues are themselves directly light-sensitive, expressing a wide range of opsin photopigments. This broad non-visual light sensitivity exists to set the clock, but also impacts a wide range of fundamental cell biological processes, such as DNA repair regulation. In this context, Astyanax mexicanus is a very intriguing model system with which to explore non-visual light detection and circadian clock function. Previous work has shown that surface fish possess the same directly light entrainable circadian clocks, described above. The same is true for cave strains of Astyanax in the laboratory, though no daily rhythms have been observed under natural dark conditions in Mexico. There are, however, clear alterations in the cave strain light response and changes to the circadian clock, with a difference in phase of peak gene expression and a reduction in amplitude. In this study, we expand these early observations by exploring the development of non-visual light sensitivity and clock function between surface and cave populations. When does the circadian pacemaker begin to oscillate during development, and are there differences between the various strains? Is the difference in acute light sensitivity, seen in adults, apparent from the earliest stages of development? Our results show that both cave and surface populations must experience daily light exposure to establish a larval gene expression rhythm. These oscillations begin early, around the third day of development in all strains, but gene expression rhythms show a significantly higher amplitude in surface fish larvae. In addition, the light induction of clock genes is developmentally delayed in cave populations. Zebrafish embryonic light sensitivity has been shown to be critical not only for clock entrainment, but also for transcriptional activation of DNA repair processes. Similar downstream transcriptional responses to light also occur in Astyanax. Interestingly, the establishment of the adult timing profile of clock gene expression takes several days to become apparent. This fact may provide mechanistic insight into the key differences between the cave and surface fish clock mechanisms. Copyright © 2018. Published by Elsevier Inc.

Endoplasmic reticulum stress increases AT1R mRNA expression via TIA-1-dependent mechanism.

PubMed

Backlund, Michael; Paukku, Kirsi; Kontula, Kimmo K; Lehtonen, Jukka Y A

2016-04-20

As the formation of ribonucleoprotein complexes is a major mechanism of angiotensin II type 1 receptor (AT1R) regulation, we sought to identify novel AT1R mRNA binding proteins. By affinity purification and mass spectroscopy, we identified TIA-1. This interaction was confirmed by colocalization of AT1R mRNA and TIA-1 by FISH and immunofluorescence microscopy. In immunoprecipitates of endogenous TIA- 1, reverse transcription-PCR amplified AT1R mRNA. TIA-1 has two binding sites within AT1R 3'-UTR. The binding site proximal to the coding region is glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-dependent whereas the distal binding site is not. TIA-1 functions as a part of endoplasmic reticulum (ER) stress response leading to stress granule (SG) formation and translational silencing. We and others have shown that AT1R expression is increased by ER stress-inducing factors. In unstressed cells, TIA-1 binds to AT1R mRNA and decreases AT1R protein expression. Fluorescence microscopy shows that ER stress induced by thapsigargin leads to the transfer of TIA-1 to SGs. In FISH analysis AT1R mRNA remains in the cytoplasm and no longer colocalizes with TIA-1. Thus, release of TIA-1-mediated suppression by ER stress increases AT1R protein expression. In conclusion, AT1R mRNA is regulated by TIA-1 in a ER stress-dependent manner. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Comparative prognostic value of epidermal growth factor quantitative protein expression compared with FISH for head and neck squamous cell carcinoma.

PubMed

Pectasides, Eirini; Rampias, Theodore; Kountourakis, Panteleimon; Sasaki, Clarence; Kowalski, Diane; Fountzilas, George; Zaramboukas, Thomas; Rimm, David; Burtness, Barbara; Psyrri, Amanda

2011-05-01

Epidermal growth factor receptor (EGFR) overexpression correlates with recurrence and with treatment resistance in head and neck squamous cell carcinoma (HNSCC). The aim of this study was to evaluate the relationship of EGFR gene copy number utilizing FISH and protein expression with automated quantitative analysis (AQUA) and to correlate those with patient outcome. A tissue microarray composed of 102 HNSCC treated with (chemo)radiation was constructed and analyzed for EGFR copy number by FISH (Vysis; Abbott Laboratories) and EGFR protein expression using AQUA analysis of EGFR staining scored on a scale of 0 to 255. We evaluated associations of EGFR FISH status and AQUA score with clinicopathologic parameters and survival prognosis. Eleven (17.2%) of 64 tumors with FISH results showed EGFR high polysomy and/or gene amplification (FISH positive). Protein levels assessed by AQUA in FISH-positive cases were significantly higher (P = 0.04) than in FISH-negative cases. Using the continuous AQUA scores for EGFR expression, AQUA and FISH showed significant agreement (Pearson's ρ = 0.353, P = 0.04). Patients with high tumor EGFR protein expression had inferior 5-year overall survival (27.7%) compared with those with low tumor EGFR expression (54%; P = 0.029). There was no significant association between EGFR FISH status and overall survival (P = 0.201). In the multivariate model, high tumor EGFR protein expression status remained an independent prognostic factor for overall survival (P = 0.047). EGFR protein content correlates with gene copy number if protein content is quantitated and automatically analyzed, as with AQUA. EGFR protein levels assessed by AQUA strongly predict for patient outcome in HNSCC, whereas EGFR FISH status does not provide prognostic information. ©2011 AACR.

The interbranchial lymphoid tissue likely contributes to immune tolerance and defense in the gills of Atlantic salmon.

PubMed

Aas, Ida Bergva; Austbø, Lars; Falk, Knut; Hordvik, Ivar; Koppang, Erling Olaf

2017-11-01

Central and peripheral immune tolerance is together with defense mechanisms a hallmark of all lymphoid tissues. In fish, such tolerance is especially important in the gills, where the intimate contact between gill tissue and the aqueous environment would otherwise lead to continual immune stimulation by innocuous antigens. In this paper, we focus on the expression of genes associated with immune regulation by the interbranchial lymphoid tissue (ILT) in an attempt to understand its role in maintaining immune homeostasis. Both healthy and virus-challenged fish were investigated, and transcript levels were examined from laser-dissected ILT, gills, head kidney and intestine. Lack of Aire expression in the ILT excluded its involvement in central tolerance and any possibility of its being an analogue to the thymus. On the other hand, the ILT appears to participate in peripheral immune tolerance due to its relatively high expression of forkhead box protein 3 (Foxp3) and other genes associated with regulatory T cells (Tregs) and immune suppression. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential modulation of ammonia excretion, Rhesus glycoproteins and ion-regulation in common carp (Cyprinus carpio) following individual and combined exposure to waterborne copper and ammonia.

PubMed

Sinha, Amit Kumar; Kapotwe, Mumba; Dabi, Shambel Boki; Montes, Caroline da Silva; Shrivastava, Jyotsna; Blust, Ronny; De Boeck, Gudrun

2016-01-01

The main objective of this study was to understand the mode of interaction between waterborne copper (Cu) and high environmental ammonia (HEA) exposure on freshwater fish, and how they influence the toxicity of each other when present together. For this purpose, individual and combined effects of Cu and HEA were examined on selected physiological and ion-regulatory processes and changes at transcript level in the common carp (Cyprinus carpio). Juvenile carp were exposed to 2.6μM Cu (25% of the 96h LC50value) and to 0.65mM ammonia (25% of the 96h LC50value) singly and as a mixture for 12h, 24h, 48h, 84h and 180h. Responses such as ammonia (Jamm) and urea (Jurea) excretion rate, plasma ammonia and urea, plasma ions (Na(+), Cl(-) and K(+)), muscle water content (MWC) as well as branchial Na(+)/K(+)-ATPase (NKA) and H(+)-ATPase activity, and branchial mRNA expression of NKA, H(+)-ATPase, Na(+)/H(+) exchanger (NHE-3) and Rhesus (Rh) glycoproteins were investigated under experimental conditions. Results show that Jamm was inhibited during Cu exposure, while HEA exposed fish were able to increase excretion efficiently. In the combined exposure, Jamm remained at the control levels indicating that Cu and HEA abolished each other's effect. Expression of Rhcg (Rhcg-a and Rhcg-b) mRNA was upregulated during HEA, thereby facilitated ammonia efflux out of gills. On the contrary, Rhcg-a transcript level declined following Cu exposure which might account for Cu induced Jamm inhibition. Likewise, Rhcg-a was also down-regulated in Cu-HEA co-exposed fish whilst a temporary increment was noted for Rhch-b. Fish exposed to HEA displayed pronounced up-regulation in NKA expression and activity and stable plasma ion levels. In both the Cu exposure alone and combined Cu-HEA exposure, ion-osmo homeostasis was adversely affected, exemplified by the significant reduction in plasma [Na(+)] and [Cl(-)], and elevated plasma [K(+)], along with an elevation in MWC. These changes were accompanied by a decline in NKA activity. Gill H(+)-ATPase mRNA levels and activities were not affected by either Cu or HEA or both. Likewise, NHE-3 expression remained unaltered but tended to be numerically higher during HEA exposure. Overall, these data suggest that at equitoxic concentrations (25% of 96h LC50), the individual effect of Cu is more harmful while HEA induces quicker adaptive responses. Our findings also denote a competitive mode of interaction, exemplified by the inhibition of HEA -mediated adaptive responses in the presence of Cu. Copyright © 2015 Elsevier B.V. All rights reserved.

Coevolutionary patterning of teeth and taste buds

PubMed Central

Bloomquist, Ryan F.; Parnell, Nicholas F.; Phillips, Kristine A.; Fowler, Teresa E.; Yu, Tian Y.; Sharpe, Paul T.; Streelman, J. Todd

2015-01-01

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium. PMID:26483492

Coevolutionary patterning of teeth and taste buds.

PubMed

Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

2015-11-03

Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

Identification, expression and function of apolipoprotein E in annual fish Nothobranchius guentheri: implication for an aging marker.

PubMed

Wang, Xia; Shang, Xiaomei; Luan, Jing; Zhang, Shicui

2014-06-01

Apolipoprotein E (apoE) is a lipid-associated protein present in both plasma and in central nervous system. Variation in apoE gene has been reported to be associated with longevity in humans as well as with aged diseases such as atherosclerosis, Alzheimer's disease, and Parkinson's disease. However, information regarding the function and structure-activity relationship of apoE in lower vertebrates is rather limited. In this study we show that the apoE gene from the annual fish Nothobranchius guentheri, NapoE, encodes a protein of 262 amino acids, which shares common structural features characteristic of mammalian apoE. We also show that like human apoE, recombinant NapoE is able to inhibit LDL oxidation, and it is the N-terminal domain of NapoE with lysine or arginine residues that plays a key role in inhibition of LDL oxidation. NapoE is predominantly expressed in the liver of N. guentheri, consistent with that in mammalian species. More importantly, we demonstrate an age-dependent down-regulation of NapoE gene, rendering it a suitable biomarker of aging. This lays a foundation for further study of the role of apoE in the aging process of fish.

Tributyltin promoted hepatic steatosis in zebrafish (Danio rerio) and the molecular pathogenesis involved.

PubMed

Zhang, Jiliang; Sun, Ping; Kong, Tao; Yang, Fan; Guan, Wenchao

2016-01-01

Endocrine disruptor effects of tributyltin (TBT) are well established in fish. However, the adverse effects on lipid metabolism are less well understood. Since the liver is the predominant site of de novo synthesis of lipids, the present study uses zebrafish (Danio rerio) to examine lipid accumulation in the livers and hepatic gene expression associated with lipid metabolism pathways. After exposure for 90 days, we found that the livers in fish exposed to TBT were yellowish in appearance and with accumulation of lipid droplet, which is consistent with the specific pathological features of steatosis. Molecular analysis revealed that TBT induced hepatic steatosis by increasing the gene expression associated with lipid transport, lipid storage, lipiogenic enzymes and lipiogenic factors in the livers. Moreover, TBT enhanced hepatic caspase-3 activity and up-regulated genes related to apoptosis and cell-death, which indicated steatotic livers of fish exposed to TBT and the subsequent liver damage were likely due to accelerated hepatocyte apoptosis or cell stress. In short, TBT can produce multiple and complex alterations in transcriptional activity of lipid metabolism and cell damage, which provides potential molecular evidence of TBT on hepatic steatosis. Copyright © 2015 Elsevier B.V. All rights reserved.

75 FR 51420 - Removing Regulations Implementing the Fish and Wildlife Conservation Act

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-20

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 83 [Docket No. FWS-R9-WSR-2010... and Wildlife Conservation Act AGENCY: Fish and Wildlife Service, Interior. ACTION: Final rule. SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are removing our regulations implementing the Fish...

Molecular characterization of estrogen receptor genes in Gobiocypris rarus and their expression upon endocrine disrupting chemicals exposure in juveniles.

PubMed

Wang, Houpeng; Wang, Jingjing; Wu, Tingting; Qin, Fang; Hu, Xiaoqi; Wang, Lihong; Wang, Zaizhao

2011-01-17

Estrogens play an important role in many physiological processes of vertebrates, mediated by estrogen receptors (ERs). The full length of the cDNAs for ERα, ERβ1, and ERβ2 were isolated and characterized from Gobiocypris rarus. G. rarus ERs shared the highest amino acid identities with counterparts of three cyprinidae species (Pimephales promelas ERα: 91.1%, Rutilus rutilus ERβ1: 92.9%, Tanichthy albonubes ERβ2: 93.5%). The phylogenic tree of vertebrate ERs indicates G. rarus ER isoforms are more related to counterparts of cyprinidae species. The expression of ERα mRNA was high in gonad and liver. The ERβ1 transcript was the highest in the liver of female fish and was evenly high in the liver, testis and intestine in male. The ERβ2 transcript was high in liver, gonad, and intestine. G. rarus juvenile at 34 days post fertilization were exposed for 3 days to endocrine disrupting chemicals including 17α-ethynylestradiol (EE2), 4-nonylphenol (NP) and bisphenol A (BPA). ER mRNA expression following the xenoestrogens' exposure was analyzed by quantitative real-time PCR. EE2 exposure at 0.01, 0.1 and 1 nM significantly up-regulated ERα transcript. ERβ1 mRNA expression was suppressed by EE2 at all concentrations. However ERβ2 transcript had opposite response to EE2 at low and high concentrations (up-regulation at 0.1 nM, down-regulation at 1 nM). Except a weak increase of ERα at 10 nM EE2, varying decrease of three ER transcripts was resulted in by NP at 10, 100 and 1000 nM. ERα transcript was significantly up-regulated by BPA at 10 nM. A non-significant weak increase in ERβ1 mRNA expression was caused by 1 nM BPA. However 1 nM and 10 nM BPA exposures resulted in significant and non-significant decrease of ERβ2 transcript, respectively. The BPA exposures at other concentrations almost had no effect on the ER transcripts. Vitellogenin (Vtg) mRNA expression profiling following exposure to three xenoestrogens indicated that Vtg transcript is a sensitive biomarker of the juvenile G. rarus at 34 dpf to the EDCs, especially to EE2. These results combined suggest that the ER genes are not modulated in the same manner by EE2, NP, and BPA and that ERs may not contribute equally to the transcriptional regulation of genes involved in fish development and reproduction. Copyright © 2010 Elsevier B.V. All rights reserved.

Identification of a distant cis-regulatory element controlling pharyngeal arch-specific expression of zebrafish gdf6a/radar

PubMed Central

Reed, Nykolaus P.; Mortlock, Douglas P.

2011-01-01

Skeletal formation is an essential and intricately regulated part of vertebrate development. Humans and mice deficient in Growth and Differentiation Factor 6 (Gdf6) have numerous skeletal abnormalities including joint fusions and cartilage reductions. The expression of Gdf6 is dynamic and in part regulated by distant evolutionarily conserved cis-regulatory elements. radar/gdf6a is a zebrafish ortholog of Gdf6 and has an essential role in embryonic patterning. Here we show that radar is transcribed in the cells surrounding and between the developing cartilages of the ventral pharyngeal arches, similar to mouse Gdf6. A 312 bp evolutionarily conserved region (ECR5), 122 kilobases downstream, drives expression in a pharyngeal arch-specific manner similar to endogenous radar/gdf6a. Deletion analysis identified a 78 bp region within ECR5 that is essential for transgene activity. This work illustrates that radar is regulated in the pharyngeal arches by a distant conserved element and suggests radar has similar functions in skeletal development in fish and mammals. PMID:20201106

A medium-chain fatty acid receptor Gpr84 in zebrafish: expression pattern and roles in immune regulation.

PubMed

Huang, Qiaoyan; Feng, Dong; Liu, Kai; Wang, Peng; Xiao, Hongyan; Wang, Ying; Zhang, Shicui; Liu, Zhenhui

2014-08-01

Gpr84 was recently identified as a receptor for medium-chain fatty acids, but its functions remain to be clarified. We reported the identification of a zebrafish Gpr84 homologue (zGpr84), which has a higher gene expression in the tissues of intestine, heart and liver. During embryogenesis, zGpr84 is maternally expressed and a significant increase is observed at segmentation period, and it is mainly restricted to the head region, pectoral fins, branchial arches, intestine and lateral line neuromast. Fasting or treatment with lipopolysaccharide (LPS) can induce significant up-regulation of zGpr84. We further demonstrated that zGpr84 is involved in the accumulation of lipid droplets in cells. Moreover, undecanoic acid (UA) can amplify LPS induced production of the proinflammatory cytokine IL-12 p40 through zGpr84, supporting the proposal that Gpr84 may play a role in directly linking fatty acid metabolism to immunological regulation. The resulting data in fish lay a foundation for a comprehensive exploration of the functions and evolution of Gpr84. Copyright © 2014 Elsevier Ltd. All rights reserved.

Natural mixtures of persistent organic pollutants (POP) increase weight gain, advance puberty, and induce changes in gene expression associated with steroid hormones and obesity in female zebrafish.

PubMed

Lyche, Jan L; Nourizadeh-Lillabadi, Rasoul; Almaas, Camilla; Stavik, Benedicte; Berg, Vidar; Skåre, Janneche Utne; Alestrøm, Peter; Ropstad, Erik

2010-01-01

In the present study, developmental and reproductive effects of lifelong exposure to environmental relevant concentrations of two natural mixtures of persistent organic pollutants (POP) were investigated using classical and molecular methods in a controlled zebrafish model. The mixtures used were extracted from burbot (Lota lota) liver originating from freshwater systems in Norway: one mixture with high levels and one mixture with background levels of polybrominated diphenyl ethers (PBDE), polychlorinated biphenyls (PCB), and dichlorodiphenyltrichloroethane metabolites (DDT). The concentration of POP measured in the zebrafish ranged from levels detected in wild fish from Lake Mjøsa to concentrations reported in human and wildlife populations, indicating that the experimental fish were exposed to concentrations comparable with wild fish. Phenotypic effects observed in both exposure groups included earlier onset of puberty, increased male/female sex ratio, and differences in body weight at 5 mo of age. Interestingly, genome-wide transcription profiling showed changes in regulation of genes involved in endocrine signaling and growth. The transcriptomics changes include key regulator genes for steroid hormone functions (ncoa3), and growth (c/ebp, ncoa3). The effects observed in the experimental zebrafish model raise the question whether chemical pollution represents a risk to reproductive health of wild fish inhabitating the freshwater system.

Biomarkers of metals exposure in fish from lead-zinc mining areas of Southeastern Missouri, USA

USGS Publications Warehouse

Schmitt, C.J.; Whyte, J.J.; Roberts, A.P.; Annis, M.L.; May, T.W.; Tillitt, D.E.

2007-01-01

The potential effects of proposed lead-zinc mining in an ecologically sensitive area were assessed by studying a nearby mining district that has been exploited for about 30 y under contemporary environmental regulations and with modern technology. Blood and liver samples representing fish of three species (largescale stoneroller, Campostoma oligolepis, n=91; longear sunfish, Lepomis megalotis, n=105; and northern hog sucker, Hypentelium nigricans, n=20) from 16 sites representing a range of conditions relative to mining activities were collected. Samples were analyzed for metals (also reported in a companion paper) and for biomarkers of metals exposure [erythrocyte ??-aminolevulinic acid dehydratase (ALA-D) activity; concentrations of zinc protoporphyrin (ZPP), iron, and hemoglobin (Hb) in blood; and hepatic metallothionein (MT) gene expression and lipid peroxidation]. Blood lead concentrations were significantly higher and ALA-D activity significantly lower in all species at sites nearest to active lead-zinc mines and in a stream contaminated by historical mining than at reference or downstream sites. ALA-D activity was also negatively correlated with blood lead concentrations in all three species but not with other metals. Iron and Hb concentrations were positively correlated in all three species, but were not correlated with any other metals in blood or liver in any species. MT gene expression was positively correlated with liver zinc concentrations, but neither MT nor lipid peroxidase differences among fish grouped according to lead concentrations were statistically significant. ZPP was not detected by hematofluorometry in most fish, but fish with detectable ZPP were from sites affected by mining. Collectively, these results confirm that metals are released to streams from active lead-zinc mining sites and are accumulated by fish. ?? 2007 Elsevier Inc. All rights reserved.

Effects of melanocortin-4 receptor agonists and antagonists on expression of genes related to reproduction in spotted scat, Scatophagus argus.

PubMed

Jiang, Dong-Neng; Li, Jian-Tao; Tao, Ya-Xiong; Chen, Hua-Pu; Deng, Si-Ping; Zhu, Chun-Hua; Li, Guang-Li

2017-05-01

Melanocortin-4 receptor (Mc4r) function related to reproduction in fish has not been extensively investigated. Here, we report on gene expression changes by real-time PCR following treatment with Mc4r agonists and antagonists in the spotted scat (Scatophagus argus). Using in vitro incubated hypothalamus, the Mc4r nonselective agonist NDP-MSH ([Nle 4 , D-Phe 7 ]-α-melanocyte stimulating hormone; 10 -6 M) and selective agonist THIQ (N-[(3R)-1, 2, 3, 4-Tetrahydroisoquinolinium-3-ylcarbonyl]- (1R)-1-(4-chlorobenzyl)-2-[4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl) piperidin-1-yl]-2-oxoethylamine; 10 -7 M) significantly increased the expression of gnrh (Gonadotropin releasing hormone), while the Mc4r nonselective antagonist SHU9119 (Ac-Nle-[Asp-His-DPhe/DNal(2')-Arg-Trp-Lys]-NH2; 10 -6 M) and selective antagonist Ipsen 5i (compound 5i synthesized in Ipsen Research Laboratories; 10 -6 M) significantly inhibited gnrh expression after 3 h of incubation. In incubated pituitary tissue, NDP-MSH and THIQ significantly increased the expression of fshb (Follicle-stimulating hormone beta subunit) and lhb (Luteinizing hormone beta subunit), while SHU9119 and Ipsen 5i significantly decreased fshb and lhb expression after 3 h of incubation. During the in vivo experiment, THIQ (1 mg/kg bw) significantly increased gnrh expression in hypothalamic tissue, as well as the fshb and lhb expression in pituitary tissue 12 h after abdominal injection. Furthermore, Ipsen 5i (1 mg/kg bw) significantly inhibited gnrh expression in hypothalamic tissue, as well as fshb and lhb gene expression in pituitary tissue 12 h after abdominal injection. In summary, Mc4r singling appears to stimulate gnrh expression in the hypothalamus, thereby modulating the synthesis of Fsh and Lh in the pituitary. In addition, Mc4r also appears to directly regulate fshb and lhb levels in the pituitary in spotted scat. Our study suggests that Mc4r, through the hypothalamus and pituitary, participates in reproductive regulation in fish.

Differential expression analysis of genes involved in high-temperature induced sex differentiation in Nile tilapia.

PubMed

Li, Chun Ge; Wang, Hui; Chen, Hong Ju; Zhao, Yan; Fu, Pei Sheng; Ji, Xiang Shan

2014-01-01

Nowadays, high temperature effects on the molecular pathways during sex differentiation in teleosts need to be deciphered. In this study, a systematic differential expression analysis of genes involved in high temperature-induced sex differentiation was done in the Nile tilapia gonad and brain. Our results showed that high temperature caused significant down-regulation of CYP19A1A in the gonad of both sexes in induction group, and FOXL2 in the ovary of the induction group. The expressions of GTHα, LHβ and ERα were also significantly down-regulated in the brain of both sexes in the induction and recovery groups. On the contrary, the expression of CYP11B2 was significantly up-regulated in the ovary, but not in the testis in both groups. Spearman rank correlation analysis showed that there are significant correlations between the expressions of CYP19A1A, FOXL2, or DMRT1 in the gonads and the expression of some genes in the brain. Another result in this study showed that high temperature up-regulated the expression level of DNMT1 in the testis of the induction group, and DNMT1 and DNMT3A in the female brain of both groups. The expression and correlation analysis of HSPs showed that high temperature action on tilapia HSPs might indirectly induce the expression changes of sex differentiation genes in the gonads. These findings provide new insights on TSD and suggest that sex differentiation related genes, heat shock proteins, and DNA methylation genes are new candidates for studying TSD in fish species. Copyright © 2014 Elsevier Inc. All rights reserved.

Analysis of Single-cell Gene Transcription by RNA Fluorescent In Situ Hybridization (FISH)

PubMed Central

Ronander, Elena; Bengtsson, Dominique C.; Joergensen, Louise; Jensen, Anja T. R.; Arnot, David E.

2012-01-01

Adhesion of Plasmodium falciparum infected erythrocytes (IE) to human endothelial receptors during malaria infections is mediated by expression of PfEMP1 protein variants encoded by the var genes. The haploid P. falciparum genome harbors approximately 60 different var genes of which only one has been believed to be transcribed per cell at a time during the blood stage of the infection. How such mutually exclusive regulation of var gene transcription is achieved is unclear, as is the identification of individual var genes or sub-groups of var genes associated with different receptors and the consequence of differential binding on the clinical outcome of P. falciparum infections. Recently, the mutually exclusive transcription paradigm has been called into doubt by transcription assays based on individual P. falciparum transcript identification in single infected erythrocytic cells using RNA fluorescent in situ hybridization (FISH) analysis of var gene transcription by the parasite in individual nuclei of P. falciparum IE1. Here, we present a detailed protocol for carrying out the RNA-FISH methodology for analysis of var gene transcription in single-nuclei of P. falciparum infected human erythrocytes. The method is based on the use of digoxigenin- and biotin- labeled antisense RNA probes using the TSA Plus Fluorescence Palette System2 (Perkin Elmer), microscopic analyses and freshly selected P. falciparum IE. The in situ hybridization method can be used to monitor transcription and regulation of a variety of genes expressed during the different stages of the P. falciparum life cycle and is adaptable to other malaria parasite species and other organisms and cell types. PMID:23070076

A novel mammal-specific three partite enhancer element regulates node and notochord-specific Noto expression.

PubMed

Alten, Leonie; Schuster-Gossler, Karin; Eichenlaub, Michael P; Wittbrodt, Beate; Wittbrodt, Joachim; Gossler, Achim

2012-01-01

The vertebrate organizer and notochord have conserved, essential functions for embryonic development and patterning. The restricted expression of developmental regulators in these tissues is directed by specific cis-regulatory modules (CRMs) whose sequence conservation varies considerably. Some CRMs have been conserved throughout vertebrates and likely represent ancestral regulatory networks, while others have diverged beyond recognition but still function over a wide evolutionary range. Here we identify and characterize a mammalian-specific CRM required for node and notochord specific (NNC) expression of NOTO, a transcription factor essential for node morphogenesis, nodal cilia movement and establishment of laterality in mouse. A 523 bp enhancer region (NOCE) upstream the Noto promoter was necessary and sufficient for NNC expression from the endogenous Noto locus. Three subregions in NOCE together mediated full activity in vivo. Binding sites for known transcription factors in NOCE were functional in vitro but dispensable for NOCE activity in vivo. A FOXA2 site in combination with a novel motif was necessary for NOCE activity in vivo. Strikingly, syntenic regions in non-mammalian vertebrates showed no recognizable sequence similarities. In contrast to its activity in mouse NOCE did not drive NNC expression in transgenic fish. NOCE represents a novel, mammal-specific CRM required for the highly restricted Noto expression in the node and nascent notochord and thus regulates normal node development and function.

Effects of salinity on metabolic rate and branchial expression of genes involved in ion transport and metabolism in Mozambique tilapia (Oreochromis mossambicus).

PubMed

Zikos, Aris; Seale, Andre P; Lerner, Darren T; Grau, E Gordon; Korsmeyer, Keith E

2014-12-01

This study investigated the effects of two rearing salinities, and acute salinity transfer, on the energetic costs of osmoregulation and the expression of metabolic and osmoregulatory genes in the gill of Mozambique tilapia. Using automated, intermittent-flow respirometry, measured standard metabolic rates (SMRs) of tilapia reared in seawater (SW, 130 mg O₂ kg⁻¹ h⁻¹) were greater than those reared in fresh water (FW, 103 mg O₂ kg⁻¹ h⁻¹), when normalized to a common mass of 0.05 kg and at 25±1°C. Transfer from FW to 75% SW increased SMR within 18h, to levels similar to SW-reared fish, while transfer from SW to FW decreased SMR to levels similar to FW-reared fish. Branchial gene expression of Na⁺-K⁺-2Cl⁻ cotransporter (NKCC), an indicator of SW-type mitochondria-rich (MR) cells, was positively correlated with SMR, while Na⁺-Cl⁻ cotransporter (NCC), an indicator of FW-type MR cells, was negatively correlated. Principal Components Analysis also revealed that branchial expression of cytochrome c oxidase subunit IV (COX-IV), glycogen phosphorylase (GP), and a putative mitochondrial biogenesis regulator in fish, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), were correlated with a higher SMR, plasma osmolality, and environmental salinity, while expression of glycogen synthase (GS), PGC-1β, and nuclear respiratory factor 1 (NRF-1) had negative correlations. These results suggest that the energetic costs of osmoregulation are higher in SW than in FW, which may be related to the salinity-dependent differences in osmoregulatory mechanisms found in the gills of Mozambique tilapia. Copyright © 2014 Elsevier Inc. All rights reserved.

Differential expression patterns of PQRFamide peptide and its two receptor genes in the brain and pituitary of grass puffer during the reproductive cycle.

PubMed

Shahjahan, Md; Doi, Hiroyuki; Ando, Hironori

2015-01-01

Pain-modulatory neuropeptides, PQRFamide (PQRFa) peptides, have recently been implicated in the regulation of reproduction in fish. As a first step toward investigating the role of PQRFa peptides on reproductive function in the grass puffer Takifugu niphobles, which is a semilunar spawner, we cloned genes encoding PQRFa peptide precursor (pqrfa) and its two types of receptors (pqrfa-r1 and pqrfa-r2), and examined changes in their expression levels in the brain and pituitary over several months during the reproductive cycle. The grass puffer PQRFa peptide precursor of 126 amino acid residues contains two putative PQRFa peptides, PQRFa-1 and PQRFa-2, which correspond to NPFF and NPAF in other vertebrates, respectively. The grass puffer PQRFa-R1 and PQRFa-R2 consist of 426 and 453 amino acid residues, respectively, and contain distinct characteristics of G-protein coupled receptors. These three genes were exclusively expressed in the brain and pituitary. The expression levels of pqrfa and pqrfa-r1 were significantly increased during the late stage of sexual maturation, but low in the spawning fish just after releasing sperms and eggs. Therefore, the grass puffer PQRFa peptide may have a role in the late stage of sexual maturation before spawning via PQRFa-R1. In contrast, the pqrfa-r2 expression showed maximum levels in the spawning fish and in the post-spawning period. The present results provide fundamental data suggesting that the grass puffer PQRFa peptide may have multiple roles in the control of reproduction that are dependent on the reproductive stages. Copyright © 2014 Elsevier Inc. All rights reserved.

Resveratrol ameliorates diet-induced dysregulation of lipid metabolism in zebrafish (Danio rerio)

PubMed Central

Li, Lin; Yan, Qiaoqiao; Yi, Weijie; Ying, Chenjiang; Wu, Hongmei

2017-01-01

Defective lipid metabolism is associated with increased risk of various chronic diseases, such as obesity, cardiovascular diseases, and diabetes. Resveratrol (RSV), a natural polyphenol, has been shown the potential of ameliorating disregulations of lipid metabolism. The objective of this study was to investigate the effects of feed intake and RSV on lipid metabolism in zebrafish (Danio rerio). The adult males were randomly allocated to 6 groups: control (Con, 8 mg cysts/fish/day), control with 20 μmol/L RSV (Con+RSV), calorie restriction (CR, 5 mg cysts/fish/day), calorie restriction with RSV (CR+RSV), overfeed (OF, 60 mg cysts/fish/day), and overfeed with RSV (OF+RSV) groups. The treatment period was 8 weeks. Results showed that CR reduced body length, body weight, and condition factor of zebrafish. CR reduced levels of plasma triglyceride (TG) and induced protein expression of phosphorylated AMP-activated protein kinase-α (pAMPKα), silent information regulator 2 homolog 1 (Sirt1), and peroxisome proliferator activated receptor gamma coactivator-1α (PGC1α). RSV attenuated CR-induced pAMPKα/AMPKαincreases. RSV increased levels of Sirt1 protein in the OF zebrafish, and decreased OF-induced increase in peroxisome proliferator-activated receptor-γ (PPARγ) protein level. Additionally, RSV down-regulated caveolin-1 and up-regulated microtubule-associated protein 1 light chain 3 -II (LC3-II) protein levels in OF zebrafish. In conclusion, these results suggest that 1) CR reduces plasma TG level through activation of the AMPKα-Sirt1- PGC1α pathway; 2) under different dietary stress conditions RSV might regulate AMPK phosphorylation bi-directionally; 3) RSV might regulate lipid metabolism through the AMPKα-Sirt1-PPARγ pathway in OF zebrafish. PMID:28686680

Liver transcriptome analysis reveals extensive transcriptional plasticity during acclimation to low salinity in Cynoglossus semilaevis.

PubMed

Si, Yufeng; Wen, Haishen; Li, Yun; He, Feng; Li, Jifang; Li, Siping; He, Huiwen

2018-06-18

Salinity is an important abiotic stress that influences the physiological and metabolic activity, reproduction, growth and development of marine fish. It has been suggested that half-smooth tongue sole (Cynoglossus semilaevis), a euryhaline fish species, uses a large amount of energy to maintain osmotic pressure balance when exposed to fluctuations in salinity. To delineate the molecular response of C. semilaevis to different levels of salinity, we performed RNA-seq analysis of the liver to identify the genes and molecular and biological processes involved in responding to salinity changes. The present study yielded 330.4 million clean reads, of which 83.9% were successfully mapped to the reference genome of C. semilaevis. One hundred twenty-eight differentially expressed genes (DEGs), including 43 up-regulated genes and 85 down-regulated genes, were identified. These DEGs were highly represented in metabolic pathways, steroid biosynthesis, terpenoid backbone biosynthesis, butanoate metabolism, glycerolipid metabolism and the 2-oxocarboxylic acid metabolism pathway. In addition, genes involved in metabolism, osmoregulation and ion transport, signal transduction, immune response and stress response, and cytoskeleton remodeling were affected during acclimation to low salinity. Genes acat2, fdps, hmgcr, hmgcs1, mvk, pmvk, ebp, lss, dhcr7, and dhcr24 were up-regulated and abat, ddc, acy1 were down-regulated in metabolic pathways. Genes aqp10 and slc6a6 were down-regulated in osmoregulation and ion transport. Genes abat, fdps, hmgcs1, mvk, pmvk and dhcr7 were first reported to be associated with salinity adaptation in teleosts. Our results revealed that metabolic pathways, especially lipid metabolism were important for salinity adaptation. The candidate genes identified from this study provide a basis for further studies to investigate the molecular mechanism of salinity adaptation and transcriptional plasticity in marine fish.

Transcriptomic characterization of cold acclimation in larval zebrafish

PubMed Central

2013-01-01

Background Temperature is one of key environmental parameters that affect the whole life of fishes and an increasing number of studies have been directed towards understanding the mechanisms of cold acclimation in fish. However, the adaptation of larvae to cold stress and the cold-specific transcriptional alterations in fish larvae remain largely unknown. In this study, we characterized the development of cold-tolerance in zebrafish larvae and investigated the transcriptional profiles under cold stress using RNA-seq. Results Pre-exposure of 96 hpf zebrafish larvae to cold stress (16°C) for 24 h significantly increased their survival rates under severe cold stress (12°C). RNA-seq generated 272 million raw reads from six sequencing libraries and about 92% of the processed reads were mapped to the reference genome of zebrafish. Differential expression analysis identified 1,431 up- and 399 down-regulated genes. Gene ontology enrichment analysis of cold-induced genes revealed that RNA splicing, ribosome biogenesis and protein catabolic process were the most highly overrepresented biological processes. Spliceosome, proteasome, eukaryotic ribosome biogenesis and RNA transport were the most highly enriched pathways for genes up-regulated by cold stress. Moreover, alternative splicing of 197 genes and promoter switching of 64 genes were found to be regulated by cold stress. A shorter isoform of stk16 that lacks 67 amino acids at the N-terminus was specifically generated by skipping the second exon in cold-treated larvae. Alternative promoter usage was detected for per3 gene under cold stress, which leading to a highly up-regulated transcript encoding a truncated protein lacking the C-terminal domains. Conclusions These findings indicate that zebrafish larvae possess the ability to build cold-tolerance under mild low temperature and transcriptional and post-transcriptional regulations are extensively involved in this acclimation process. PMID:24024969

Intestinal transcriptome analysis revealed differential salinity adaptation between two tilapiine species.

PubMed

Ronkin, Dana; Seroussi, Eyal; Nitzan, Tali; Doron-Faigenboim, Adi; Cnaani, Avner

2015-03-01

Tilapias are a group of freshwater species, which vary in their ability to adapt to high salinity water. Osmotic regulation in fish is conducted mainly in the gills, kidney, and gastrointestinal tract (GIT). The mechanisms involved in ion and water transport through the GIT is not well-characterized, with only a few described complexes. Comparing the transcriptome of the anterior and posterior intestinal sections of a freshwater and saltwater adapted fish by deep-sequencing, we examined the salinity adaptation of two tilapia species: the high salinity-tolerant Oreochromis mossambicus (Mozambique tilapia), and the less salinity-tolerant Oreochromis niloticus (Nile tilapia). This comparative analysis revealed high similarity in gene expression response to salinity change between species in the posterior intestine and large differences in the anterior intestine. Furthermore, in the anterior intestine 68 genes were saltwater up-regulated in one species and down-regulated in the other species (47 genes up-regulated in O. niloticus and down-regulated in O. mossambicus, with 21 genes showing the reverse pattern). Gene ontology (GO) analysis showed a high proportion of transporter and ion channel function among these genes. The results of this study point to a group of genes that differed in their salinity-dependent regulation pattern in the anterior intestine as potentially having a role in the differential salinity tolerance of these two closely related species. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of different omega-3 sources, fish oil, krill oil, and green-lipped mussel against cytokine-mediated canine cartilage degradation.

PubMed

Buddhachat, Kittisak; Siengdee, Puntita; Chomdej, Siriwadee; Soontornvipart, Kumpanart; Nganvongpanit, Korakot

2017-05-01

Our purpose was to evaluate the protective effect of three marine omega-3 sources, fish oil (FO), krill oil (KO), and green-lipped mussel (GLM) against cartilage degradation. Canine cartilage explants were stimulated with either 10 ng/mL interleukin-1β (IL-1β) or IL-1β/oncostatin M (10 ng/mL each) and then treated with various concentrations of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA; 3 and 30 μg/mL), FO, KO, or GLM (250, 500, and 1000 μg/mL) for 28 days. Gene expression was then investigated in primary canine chondrocytes. Our results showed that DHA and EPA as well as omega-3 sources could suppress matrix degradation in cytokine-induced cartilage explants by significantly reducing the increase of sulfated glycosaminoglycans (s-GAGs) and preserving uronic acid and hydroxyproline content (except GLM). These agents were not able to reduce IL-1β-induced IL1B and TNFA expression but were able to down-regulate the expression of the catabolic genes MMP1, MMP3, and MMP13 and up-regulate the anabolic genes AGG and COL2A1; FO and KO were especially effective. Our findings indicated that FO and KO were superior to GLM for their protective effect against proteoglycan and collagen degradation. Hence, FO and KO could serve as promising sources of chondroprotective agents.

77 FR 41001 - 2012-2013 Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-11

... other refuges that pertain to migratory game bird hunting, upland game hunting, big game hunting, and... refuge-specific hunting and sport fishing regulations when we open wildlife refuges to migratory game bird hunting, upland game hunting, big game hunting, or sport fishing. These regulations list the...

RNA expression in a cartilaginous fish cell line reveals ancient 3′ noncoding regions highly conserved in vertebrates

PubMed Central

Forest, David; Nishikawa, Ryuhei; Kobayashi, Hiroshi; Parton, Angela; Bayne, Christopher J.; Barnes, David W.

2007-01-01

We have established a cartilaginous fish cell line [Squalus acanthias embryo cell line (SAE)], a mesenchymal stem cell line derived from the embryo of an elasmobranch, the spiny dogfish shark S. acanthias. Elasmobranchs (sharks and rays) first appeared >400 million years ago, and existing species provide useful models for comparative vertebrate cell biology, physiology, and genomics. Comparative vertebrate genomics among evolutionarily distant organisms can provide sequence conservation information that facilitates identification of critical coding and noncoding regions. Although these genomic analyses are informative, experimental verification of functions of genomic sequences depends heavily on cell culture approaches. Using ESTs defining mRNAs derived from the SAE cell line, we identified lengthy and highly conserved gene-specific nucleotide sequences in the noncoding 3′ UTRs of eight genes involved in the regulation of cell growth and proliferation. Conserved noncoding 3′ mRNA regions detected by using the shark nucleotide sequences as a starting point were found in a range of other vertebrate orders, including bony fish, birds, amphibians, and mammals. Nucleotide identity of shark and human in these regions was remarkably well conserved. Our results indicate that highly conserved gene sequences dating from the appearance of jawed vertebrates and representing potential cis-regulatory elements can be identified through the use of cartilaginous fish as a baseline. Because the expression of genes in the SAE cell line was prerequisite for their identification, this cartilaginous fish culture system also provides a physiologically valid tool to test functional hypotheses on the role of these ancient conserved sequences in comparative cell biology. PMID:17227856

An integrated genomic approach for the study of mandibular prognathism in the European seabass (Dicentrarchus labrax).

PubMed

Babbucci, Massimiliano; Ferraresso, Serena; Pauletto, Marianna; Franch, Rafaella; Papetti, Chiara; Patarnello, Tomaso; Carnier, Paolo; Bargelloni, Luca

2016-12-08

Skeletal anomalies in farmed fish are a relevant issue affecting animal welfare and health and causing significant economic losses. Here, a high-density genetic map of European seabass for QTL mapping of jaw deformity was constructed and a genome-wide association study (GWAS) was carried out on a total of 298 juveniles, 148 of which belonged to four full-sib families. Out of 298 fish, 107 were affected by mandibular prognathism (MP). Three significant QTLs and two candidate SNPs associated with MP were identified. The two GWAS candidate markers were located on ChrX and Chr17, both in close proximity with the peaks of the two most significant QTLs. Notably, the SNP marker on Chr17 was positioned within the Sobp gene coding region, which plays a pivotal role in craniofacial development. The analysis of differentially expressed genes in jaw-deformed animals highlighted the "nervous system development" as a crucial pathway in MP. In particular, Zic2, a key gene for craniofacial morphogenesis in model species, was significantly down-regulated in MP-affected animals. Gene expression data revealed also a significant down-regulation of Sobp in deformed larvae. Our analyses, integrating transcriptomic and GWA methods, provide evidence for putative mechanisms underlying seabass jaw deformity.

An integrated genomic approach for the study of mandibular prognathism in the European seabass (Dicentrarchus labrax)

PubMed Central

Babbucci, Massimiliano; Ferraresso, Serena; Pauletto, Marianna; Franch, Rafaella; Papetti, Chiara; Patarnello, Tomaso; Carnier, Paolo; Bargelloni, Luca

2016-01-01

Skeletal anomalies in farmed fish are a relevant issue affecting animal welfare and health and causing significant economic losses. Here, a high-density genetic map of European seabass for QTL mapping of jaw deformity was constructed and a genome-wide association study (GWAS) was carried out on a total of 298 juveniles, 148 of which belonged to four full-sib families. Out of 298 fish, 107 were affected by mandibular prognathism (MP). Three significant QTLs and two candidate SNPs associated with MP were identified. The two GWAS candidate markers were located on ChrX and Chr17, both in close proximity with the peaks of the two most significant QTLs. Notably, the SNP marker on Chr17 was positioned within the Sobp gene coding region, which plays a pivotal role in craniofacial development. The analysis of differentially expressed genes in jaw-deformed animals highlighted the “nervous system development” as a crucial pathway in MP. In particular, Zic2, a key gene for craniofacial morphogenesis in model species, was significantly down-regulated in MP-affected animals. Gene expression data revealed also a significant down-regulation of Sobp in deformed larvae. Our analyses, integrating transcriptomic and GWA methods, provide evidence for putative mechanisms underlying seabass jaw deformity. PMID:27929136

Changes in cholecystokinin and peptide Y gene expression with feeding in yellowtail (Seriola quinqueradiata): relation to pancreatic exocrine regulation.

PubMed

Murashita, Koji; Fukada, Haruhisa; Hosokawa, Hidetsuyo; Masumoto, Toshiro

2007-03-01

In fish, the regulation of digestive enzyme secretion by hormonal control such as cholecystokinin (CCK) and neuropeptide Y (NPY)-related peptide is not well understood. To investigate the roles of fish CCK and peptide Y (PY) in digestive enzyme secretion, mRNA levels of CCK and PY, pyloric caeca enzyme activities and mRNA levels of pancreatic digestive enzymes (lipase, trypsin and amylase) were measured at pre- and post-prandial stages in yellowtail. Pyloric caeca were sampled at 0, 0.5, 1.5, 3, 6, 12, 24 and 48 h after feeding. The mRNA levels of trypsin and amylase increased after feeding, suggesting that transcription was induced by feed ingestion. Digestive enzyme activities decreased in exocrine pancreas after feeding, suggesting the stored enzyme was secreted from pancreas post-prandially. mRNA levels for CCK displayed a time-dependent increase, peaking between 1.5 and 3 h after-feeding followed by a rapid decrease 3 to 6 h after feeding. The mRNA expression pattern of PY was inverse to the pattern of CCK, decreasing until 1.5 h after feeding and then rising to initial levels by 12 h after feeding. These results suggest that CCK and PY work antagonistically in the exocrine pancreas of yellowtail.

A Caenorhabditis elegans protein with a PRDM9-like SET domain localizes to chromatin-associated foci and promotes spermatocyte gene expression, sperm production and fertility.

PubMed

Engert, Christoph G; Droste, Rita; van Oudenaarden, Alexander; Horvitz, H Robert

2018-04-01

To better understand the tissue-specific regulation of chromatin state in cell-fate determination and animal development, we defined the tissue-specific expression of all 36 C. elegans presumptive lysine methyltransferase (KMT) genes using single-molecule fluorescence in situ hybridization (smFISH). Most KMTs were expressed in only one or two tissues. The germline was the tissue with the broadest KMT expression. We found that the germline-expressed C. elegans protein SET-17, which has a SET domain similar to that of the PRDM9 and PRDM7 SET-domain proteins, promotes fertility by regulating gene expression in primary spermatocytes. SET-17 drives the transcription of spermatocyte-specific genes from four genomic clusters to promote spermatid development. SET-17 is concentrated in stable chromatin-associated nuclear foci at actively transcribed msp (major sperm protein) gene clusters, which we term msp locus bodies. Our results reveal the function of a PRDM9/7-family SET-domain protein in spermatocyte transcription. We propose that the spatial intranuclear organization of chromatin factors might be a conserved mechanism in tissue-specific control of transcription.

Molecular characterization of melanin-concentrating hormone (MCH) in Schizothorax prenanti: cloning, tissue distribution and role in food intake regulation.

PubMed

Wang, Tao; Yuan, Dengyue; Zhou, Chaowei; Lin, Fangjun; Wei, Rongbin; Chen, Hu; Wu, Hongwei; Xin, Zhiming; Liu, Ju; Gao, Yundi; Chen, Defang; Yang, Shiyong; Wang, Yan; Pu, Yundan; Li, Zhiqiong

2016-06-01

Melanin-concentrating hormone (MCH) is a crucial neuropeptide involved in various biological functions in both mammals and fish. In this study, the full-length MCH cDNA was obtained from Schizothorax prenanti by rapid amplification of cDNA ends polymerase chain reaction. The full-length MCH cDNA contained 589 nucleotides including an open reading frame of 375 nucleotides encoding 256 amino acids. MCH mRNA was highly expressed in the brain by real-time quantitative PCR analysis. Within the brain, expression of MCH mRNA was preponderantly detected in the hypothalamus. In addition, the MCH mRNA expression in the S. prenanti hypothalamus of fed group was significantly decreased compared with the fasted group at 1 and 3 h post-feeding, respectively. Furthermore, the MCH gene expression presented significant increase in the hypothalamus of fasted group compared with the fed group during long-term fasting. After re-feeding, there was a dramatic decrease in MCH mRNA expression in the hypothalamus of S. prenanti. The results indicate that the expression of MCH is affected by feeding status. Taken together, our results suggest that MCH may be involved in food intake regulation in S. prenanti.

Expression analysis of the insulin-like growth factors I and II during embryonic and early larval development of turbot ( Scophthalmus maximus)

NASA Astrophysics Data System (ADS)

Wen, Haishen; Qi, Qian; Hu, Jian; Si, Yufeng; He, Feng; Li, Jifang

2015-04-01

The insulin-like growth factors I and II (IGF-I and IGF-II) are important proteins involved in fish growth and development. Here, we report the isolation of IGF-II and expression analysis of IGFs in turbot Scophthalmus maximus, aiming to clarify their function in embryonic and larval development of fish. The deduced IGF-II gene is 808 bp in full length, which encodes a protein of 219 amino acids and is 93% similar with that of Paralichthys olicaceus in amino acid sequence. The tissue abundance and the expression pattern of IGFs in a turbot at early development stages were investigated via reverse transcription-polymer chain reaction. Result showed that the IGF-I and IGF-II genes were widely expressed in tissues of S. maximus. IGF-I was detected in all tissues except intestines with the highest level in liver, while IGF-II transcript presented in all tissues except muscle. At the stages of embryonic and larval development, the mRNA levels of IGFs sharply increased from the stage of unfertilized egg to post larva, followed by a decrease with larval development. However, there was an increase in IGF-I at the embryonic stage and IGF-II at the gastrula stage, respectively. These results suggested that IGFs play important roles in cell growth and division of the turbot. Our study provides reference data for further investigation of growth regulation in turbot, which can guarantee better understanding of the physiological role that IGFs play in fish.

Differential regulation of luteinizing hormone and follicle-stimulating hormone expression during ovarian development and under sexual steroid feedback in the European eel.

PubMed

Schmitz, Monika; Aroua, Salima; Vidal, Bernadette; Le Belle, Nadine; Elie, Pierre; Dufour, Sylvie

2005-01-01

Pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are, in teleosts as in mammals, under the control of hypothalamic factors and steroid feedbacks. In teleosts, feedback regulations largely vary depending on species and physiological stage. In the present study the regulation of FSH and LH expression was investigated in the European eel, a fish of biological and phylogenetical interest as a representative of an early group of teleosts. The eel FSHbeta subunit was cloned, sequenced and together with earlier isolated eel LHbeta and glycoprotein hormone alpha (GPalpha) subunits used to study the differential regulation of LH and FSH. In situ hybridization indicated that FSHbeta and LHbeta are expressed by separate cells of the proximal pars distalis of the adenohypophysis, differently from the situation in mammals. The profiles of LHbeta and FSHbeta subunit expression were compared during experimental ovarian maturation, using dot-blot assays. Expression levels for LHbeta and GPalpha increased throughout ovarian development with a positive correlation between these two subunits. Conversely, FSHbeta mRNA levels decreased. To understand the role of sex steroids in these opposite variations, immature eels were treated with estradiol (E2)and testosterone (T), both steroids being produced in eel ovaries during gonadal development. E2 treatment induced increases in both LHbeta and GPalpha mRNA levels, without any significant effect on FSHbeta. In contrast, T treatment induced a decrease in FSHbeta mRNA levels, without any significant effect on the other subunits. These data demonstrate that steroids exert a differential feedback on eel gonadotropin expression, with an E2-specific positive feedback on LH and a T-specific negative feedback on FSH, leading to an opposite regulation of LH and FSH during ovarian development. Copyright 2005 S. Karger AG, Basel

Light directs zebrafish period2 expression via conserved D and E boxes.

PubMed

Vatine, Gad; Vallone, Daniela; Appelbaum, Lior; Mracek, Philipp; Ben-Moshe, Zohar; Lahiri, Kajori; Gothilf, Yoav; Foulkes, Nicholas S

2009-10-01

For most species, light represents the principal environmental signal for entraining the endogenous circadian clock. The zebrafish is a fascinating vertebrate model for studying this process since unlike mammals, direct exposure of most of its tissues to light leads to local clock entrainment. Importantly, light induces the expression of a set of genes including certain clock genes in most zebrafish cell types in vivo and in vitro. However, the mechanism linking light to gene expression remains poorly understood. To elucidate this key mechanism, here we focus on how light regulates transcription of the zebrafish period2 (per2) gene. Using transgenic fish and stably transfected cell line-based assays, we define a Light Responsive Module (LRM) within the per2 promoter. The LRM lies proximal to the transcription start site and is both necessary and sufficient for light-driven gene expression and also for a light-dependent circadian clock regulation. Curiously, the LRM sequence is strongly conserved in other vertebrate per2 genes, even in species lacking directly light-sensitive peripheral clocks. Furthermore, we reveal that the human LRM can substitute for the zebrafish LRM to confer light-regulated transcription in zebrafish cells. The LRM contains E- and D-box elements that are critical for its function. While the E-box directs circadian clock regulation by mediating BMAL/CLOCK activity, the D-box confers light-driven expression. The zebrafish homolog of the thyrotroph embryonic factor binds efficiently to the LRM D-box and transactivates expression. We demonstrate that tef mRNA levels are light inducible and that knock-down of tef expression attenuates light-driven transcription from the per2 promoter in vivo. Together, our results support a model where a light-dependent crosstalk between E- and D-box binding factors is a central determinant of per2 expression. These findings extend the general understanding of the mechanism whereby the clock is entrained by light and how the regulation of clock gene expression by light has evolved in vertebrates.

Dietary administration of the probiotic SpPdp11: Effects on the intestinal microbiota and immune-related gene expression of farmed Solea senegalensis treated with oxytetracycline.

PubMed

Tapia-Paniagua, S T; Vidal, S; Lobo, C; García de la Banda, I; Esteban, M A; Balebona, M C; Moriñigo, M A

2015-10-01

Few antimicrobials are currently authorised in the aquaculture industry to treat infectious diseases. Among them, oxytetracycline (OTC) is one of the first-choice drugs for nearly all bacterial diseases. The objective of this study was to evaluate the effect of the dietary administration of OTC both alone and jointly with the probiotic Shewanella putrefaciens Pdp11 (SpPdp11) on the intestinal microbiota and hepatic expression of genes related to immunity in Senegalese sole (Solea senegalensis) juveniles. The results demonstrated that the richness and diversity of the intestinal microbiota of fish treated with OTC decreased compared with those of the control group but that these effects were lessened by the simultaneous administration of SpPdp11. In addition, specimens that received OTC and SpPdp11 jointly showed a decreased intensity of the Denaturing Gradient Gel Electrophoresis (DGGE) bands related to Vibrio genus and the presence of DGGE bands related to Lactobacillus and Shewanella genera. The relationship among the intestinal microbiota of fish fed with control and OTC diets and the expression of the NADPH oxidase and CASPASE-6 genes was demonstrated by a Principal Components Analysis (PCA) carried out in this study. In contrast, a close relationship between the transcription of genes, such as NKEF, IGF-β, HSP70 and GP96, and the DGGE bands of fish treated jointly with OTC and SpPdp11 was observed in the PCA study. In summary, the results obtained in this study demonstrate that the administration of OTC results in the up-regulation of genes related to apoptosis but that the joint administration of OTC and S. putrefaciens Pdp11 increases the transcription of genes related to antiapoptotic effects and oxidative stress regulation. Further, a clear relationship between these changes and those detected in the intestinal microbiota is established. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Novel Soluble Immune-Type Receptor (SITR) in Teleost Fish: Carp SITR Is Involved in the Nitric Oxide-Mediated Response to a Protozoan Parasite

PubMed Central

Ribeiro, Carla M. S.; Bird, Steve; Raes, Geert; Ghassabeh, Gholamreza H.; Schijns, Virgil E. J. C.; Pontes, Maria J. S. L.; Savelkoul, Huub F. J.; Wiegertjes, Geert F.

2011-01-01

Background The innate immune system relies upon a wide range of germ-line encoded receptors including a large number of immunoglobulin superfamily (IgSF) receptors. Different Ig-like immune receptor families have been reported in mammals, birds, amphibians and fish. Most innate immune receptors of the IgSF are type I transmembrane proteins containing one or more extracellular Ig-like domains and their regulation of effector functions is mediated intracellularly by distinct stimulatory or inhibitory pathways. Methodology/Principal Findings Carp SITR was found in a substracted cDNA repertoire from carp macrophages, enriched for genes up-regulated in response to the protozoan parasite Trypanoplasma borreli. Carp SITR is a type I protein with two extracellular Ig domains in a unique organisation of a N-proximal V/C2 (or I-) type and a C-proximal V-type Ig domain, devoid of a transmembrane domain or any intracytoplasmic signalling motif. The carp SITR C-proximal V-type Ig domain, in particular, has a close sequence similarity and conserved structural characteristics to the mammalian CD300 molecules. By generating an anti-SITR antibody we could show that SITR protein expression was restricted to cells of the myeloid lineage. Carp SITR is abundantly expressed in macrophages and is secreted upon in vitro stimulation with the protozoan parasite T. borreli. Secretion of SITR protein during in vivo T. borreli infection suggests a role for this IgSF receptor in the host response to this protozoan parasite. Overexpression of carp SITR in mouse macrophages and knock-down of SITR protein expression in carp macrophages, using morpholino antisense technology, provided evidence for the involvement of carp SITR in the parasite-induced NO production. Conclusion/Significance We report the structural and functional characterization of a novel soluble immune-type receptor (SITR) in a teleost fish and propose a role for carp SITR in the NO-mediated response to a protozoan parasite. PMID:21305002

Effect of dietary arginine on growth, intestinal enzyme activities and gene expression in muscle, hepatopancreas and intestine of juvenile Jian carp (Cyprinus carpio var. Jian).

PubMed

Chen, Gangfu; Feng, Lin; Kuang, Shengyao; Liu, Yang; Jiang, Jun; Hu, Kai; Jiang, Weidan; Li, Shuhong; Tang, Ling; Zhou, Xiaoqiu

2012-07-01

The present study was conducted to test the hypothesis that dietary arginine promotes digestion and absorption capacity, and, thus, enhances fish growth. This improvement might be related to the target of rapamycin (TOR) and eIF4E-binding protein (4E-BP). A total of 1200 juvenile Jian carp, Cyprinus carpio var. Jian, with an average initial weight of 6.33 (SE 0.03) g, were fed with diets containing graded concentrations of arginine, namely, 9.8 (control), 12.7, 16.1, 18.5, 21.9 and 24.5 g arginine/kg diet for 9 weeks. An real-time quantitative PCR analysis was performed to determine the relative expression of TOR and 4E-BP in fish muscle, hepatopancreas and intestine. Dietary arginine increased (P < 0.05): (1) glutamate-oxaloacetate transaminase and glutamate-pyruvate transaminase activities in muscle and hepatopancreas; (2) intestine and hepatopancreas protein content, folds height, and trypsin, chymotrypsin, lipase, Na⁺/K⁺-ATPase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase activities in intestine; (3) Lactobacillus counts; (4) relative expression of TOR in the muscle, hepatopancreas and distal intestine (DI); (5) relative expression of 4E-BP in proximal intestine (PI) and mid-intestine (MI), as compared with the control group. In contrast, dietary arginine reduced (P < 0.05): (1) plasma ammonia content; (2) Aeromonas hydrophila and Escherichia coli counts; (3) relative expression of TOR in PI and MI; (4) relative expression of 4E-BP in the muscle, hepatopancreas and DI. The arginine requirement estimated by specific growth rate using quadratic regression analysis was found to be 18.0 g/kg diet. These results indicate that arginine improved fish growth, digestive and absorptive ability and regulated the expression of TOR and 4E-BP genes.

AMP-Activated Protein Kinase Plays an Important Evolutionary Conserved Role in the Regulation of Glucose Metabolism in Fish Skeletal Muscle Cells

PubMed Central

Magnoni, Leonardo J.; Vraskou, Yoryia; Palstra, Arjan P.; Planas, Josep V.

2012-01-01

AMPK, a master metabolic switch, mediates the observed increase of glucose uptake in locomotory muscle of mammals during exercise. AMPK is activated by changes in the intracellular AMP∶ATP ratio when ATP consumption is stimulated by contractile activity but also by AICAR and metformin, compounds that increase glucose transport in mammalian muscle cells. However, the possible role of AMPK in the regulation of glucose metabolism in skeletal muscle has not been investigated in other vertebrates, including fish. In this study, we investigated the effects of AMPK activators on glucose uptake, AMPK activity, cell surface levels of trout GLUT4 and expression of GLUT1 and GLUT4 as well as the expression of enzymes regulating glucose disposal and PGC1α in trout myotubes derived from a primary muscle cell culture. We show that AICAR and metformin significantly stimulated glucose uptake (1.6 and 1.3 fold, respectively) and that Compound C completely abrogated the stimulatory effects of the AMPK activators on glucose uptake. The combination of insulin and AMPK activators did not result in additive nor synergistic effects on glucose uptake. Moreover, exposure of trout myotubes to AICAR and metformin resulted in an increase in AMPK activity (3.8 and 3 fold, respectively). We also provide evidence suggesting that stimulation of glucose uptake by AMPK activators in trout myotubes may take place, at least in part, by increasing the cell surface and mRNA levels of trout GLUT4. Finally, AICAR increased the mRNA levels of genes involved in glucose disposal (hexokinase, 6-phosphofructokinase, pyruvate kinase and citrate synthase) and mitochondrial biogenesis (PGC-1α) and did not affect glycogen content or glycogen synthase mRNA levels in trout myotubes. Therefore, we provide evidence, for the first time in non-mammalian vertebrates, suggesting a potentially important role of AMPK in stimulating glucose uptake and utilization in the skeletal muscle of fish. PMID:22359576

Molecular responses to toxicological stressors: profiling microRNAs in wild Atlantic salmon (Salmo salar) exposed to acidic aluminum-rich water.

PubMed

Kure, Elin H; Sæbø, Mona; Stangeland, Astrid M; Hamfjord, Julian; Hytterød, Sigurd; Heggenes, Jan; Lydersen, Espen

2013-08-15

Atlantic salmon (Salmo salar) is among the most sensitive organisms toward acidic, aluminum exposure. Main documented responses to this type of stress are a combination of hypoxia and loss of blood plasma ions. Physiological responses to stress in fish are often grouped into primary, secondary and tertiary responses, where the above mentioned effects are secondary responses, while primary responses include endocrine changes as measurable levels of catecholamines and corticosteroids. In this study we have exposed young (14 months) Atlantic salmon to acid/Al water (pH ≈ 5.6, Al(i) ≈ 80 μg L⁻¹) for 3 days, and obtained clear and consistent decrease of Na⁺ and Cl⁻ ions, and increases of glucose in blood plasma, hematocrit and P(CO₂) in blood. We did not measure plasma cortisol (primary response compound), but analyzed effects on microRNA level (miRNA) in muscle tissue, as this may represent initial markers of primary stress responses. miRNAs regulate diverse biological processes, many are evolutionarily conserved, and hundreds have been identified in various animals, although only in a few fish species. We used a novel high-throughput sequencing (RNA-Seq) method to identify miRNAs in Atlantic salmon and specific miRNAs as potential early markers for stress. A total of 18 miRNAs were significantly differentially expressed (FDR<0.1) in exposed compared to control fish, four down-regulated and 14 up-regulated. An unsupervised hierarchical clustering of significant miRNAs revealed two clusters representing exposed and non-exposed individuals. Utilizing the genome of the zebrafish and bioinformatic tools, we identified 224 unique miRNAs in the Atlantic salmon samples sequenced. Additional laboratory studies focusing on function, stress dose-responses and temporal expression of the identified miRNAs will facilitate their use as initial markers for stress responses. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Lxr regulates lipid metabolic and visual perception pathways during zebrafish development.

PubMed

Pinto, Caroline Lucia; Kalasekar, Sharanya Maanasi; McCollum, Catherine W; Riu, Anne; Jonsson, Philip; Lopez, Justin; Swindell, Eric C; Bouhlatouf, Abdel; Balaguer, Patrick; Bondesson, Maria; Gustafsson, Jan-Åke

2016-01-05

The Liver X Receptors (LXRs) play important roles in multiple metabolic pathways, including fatty acid, cholesterol, carbohydrate and energy metabolism. To expand the knowledge of the functions of LXR signaling during embryonic development, we performed a whole-genome microarray analysis of Lxr target genes in zebrafish larvae treated with either one of the synthetic LXR ligands T0901317 or GW3965. Assessment of the biological processes enriched by differentially expressed genes revealed a prime role for Lxr in regulating lipid metabolic processes, similarly to the function of LXR in mammals. In addition, exposure to the Lxr ligands induced changes in expression of genes in the neural retina and lens of the zebrafish eye, including the photoreceptor guanylate cyclase activators and lens gamma crystallins, suggesting a potential novel role for Lxr in modulating the transcription of genes associated with visual function in zebrafish. The regulation of expression of metabolic genes was phenotypically reflected in an increased absorption of yolk in the zebrafish larvae, and changes in the expression of genes involved in visual perception were associated with morphological alterations in the retina and lens of the developing zebrafish eye. The regulation of expression of both lipid metabolic and eye specific genes was sustained in 1 month old fish. The transcriptional networks demonstrated several conserved effects of LXR activation between zebrafish and mammals, and also identified potential novel functions of Lxr, supporting zebrafish as a promising model for investigating the role of Lxr during development. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Lxr regulates lipid metabolic and visual perception pathways during zebrafish development

PubMed Central

Pinto, Caroline Lucia; Kalasekar, Sharanya Maanasi; McCollum, Catherine W.; Riu, Anne; Jonsson, Philip; Lopez, Justin; Swindell, Eric; Bouhlatouf, Abdel; Balaguer, Patrick; Bondesson, Maria; Gustafsson, Jan-Åke

2015-01-01

The Liver X Receptors (LXRs) play important roles in multiple metabolic pathways, including fatty acid, cholesterol, carbohydrate and energy metabolism. To expand the knowledge of the functions of LXR signaling during embryonic development, we performed a whole-genome microarray analysis of Lxr target genes in zebrafish larvae treated with either one of the synthetic LXR ligands T0901317 or GW3965. Assessment of the biological processes enriched by differentially expressed genes revealed a prime role for Lxr in regulating lipid metabolic processes, similarly to the function of LXR in mammals. In addition, exposure to the Lxr ligands induced changes in expression of genes in the neural retina and lens of the zebrafish eye, including the photoreceptor guanylate cyclase activators and lens gamma crystallins, suggesting a potential novel role for Lxr in modulating the transcription of genes associated with visual function in zebrafish. The regulation of expression of metabolic genes was phenotypically reflected in an increased absorption of yolk in the zebrafish larvae, and changes in the expression of genes involved in visual perception were associated with morphological alterations in the retina and lens of the developing zebrafish eye. The regulation of expression of both lipid metabolic and eye specific genes was sustained in 1 month old fish. The transcriptional networks demonstrated several conserved effects of LXR activation between zebrafish and mammals, and also identified potential novel functions of Lxr, supporting zebrafish as a promising model for investigating the role of Lxr during development. PMID:26427652

Transcriptome Profiling of the Abdominal Skin of Larimichthys crocea in Light Stress

NASA Astrophysics Data System (ADS)

Han, Zhaofang; Lv, Changhuan; Xiao, Shijun; Ye, Kun; Zhang, Dongling; Tsai, Huai Jen; Wang, Zhiyong

2018-04-01

Large yellow croaker ( Larimichthys crocea), one of the most important marine fish species in China, can change its abdominal skin color when it is shifted from light to dark or from dark to light, providing us an opportunity of investigating the molecular responding mechanism of teleost in light stress. The gene expression profile of fish under light stress is rarely documented. In this research, the transcriptome profiles of the abdominal skin of L. crocea exposed to light or dark for 0 h, 0.5 h and 2 h were produced by next-generation sequencing (NGS). The cluster results demonstrated that stress period, rather than light intensity ( e.g., light or dark), is the major influencing factor. Differently expressed genes (DEGs) were identified between 0 h and 0.5 h groups, between 0 h and 2 h groups, between 0.5 h light and 0.5 h dark, and between 2 h light and 2 h dark, respectively. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation revealed that the genes relating to immunity, energy metabolism, and cytoskeletal protein binding were significantly enriched. The detailed analysis of transcriptome profiles also revealed regular gene expression trends, indicating that the elaborate gene regulation networks underlined the molecular responses of the fish to light stress. This transcriptome analysis suggested that systematic and complicated regulatory cascades were functionally activated in response to external stress, and coloration change caused by light stress was mainly attributed to the change in the density of chromatophores for L. crocea. This study also provided valuable information for skin coloration or light stress research on other marine fish species.

Interferon regulatory factor 3 (IRF-3) in Japanese flounder, Paralichthys olivaceus: sequencing, limited tissue distribution, inducible expression and induction of fish type I interferon promoter.

PubMed

Hu, Guobin; Yin, Xiangyan; Lou, Huimin; Xia, Jun; Dong, Xianzhi; Zhang, Jianyie; Liu, Qiuming

2011-02-01

Two cDNAs with different 3'-untranslated region (UTR) encoding an interferon regulatory factor 3 (IRF-3) were cloned from head kidney of Japanese flounder, Paralichthys olivaceus, by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. Sequence analysis reveals that they were generated by alternative polyadenylation. The predicted protein consists of 467 amino acid residues which shares the highest identity of 50.7-57.6% to fish IRF-3 and possesses a DNA-binding domain (DBD), an IRF association domain (IAD) and a serine-rich domain (SRD) of vertebrate IRF-3. The presence of these domains along with phylogenetic analysis places it into the IRF-3 group of the IRF-3 subfamily. RT-PCR analysis revealed that flounder IRF-3 was expressed constitutively in limited tissue types including head kidney, spleen, kidney, heart, gill, intestine and liver. A quantitative real time PCR assay was employed to monitor expression of IRF-3, type I interferon (IFN) and Mx in flounder head kidney and gill. All three genes were up-regulated by polyinosinic:polycytidylic acid (polyI:C) and lymphocystis disease virus (LCDV) with an earlier but slight and less persistent increase in transcription levels seen for the IRF-3. Finally, flounder IRF-3 was proved to induce fish type I IFN promoter in FG9307 cells, a flounder gill cell line, by a luciferase assay. These results provide insights into the roles of fish IRF-3 in the antiviral immunity. Copyright © 2010 Elsevier Ltd. All rights reserved.

Molecular characterization of a fish-specific toll-like receptor 22 (TLR22) gene from common carp (Cyprinus carpio L.): Evolutionary relationship and induced expression upon immune stimulants.

PubMed

Li, Hua; Yang, Guiwen; Ma, Fei; Li, Ting; Yang, Huiting; Rombout, Jan H W M; An, Liguo

2017-04-01

In the host innate immune system, various pattern recognition receptors (PRRs) recognize conserved pathogens-associated molecular patterns (PAMPs), and represent an efficient first line of defense against invading pathogens. TLR22 is one of the fish-specific Toll-like receptors (TLRs), identified in a variety of fish species. In this study, we report the cloning and identification of a TLR22 cDNA from the gills of common carp (Cyprinus carpio L.). The full-length CcTLR22 cDNA was 3301 bp long, including a 32 bp 5'-untranslated region (UTR), an open reading frame (ORF) of 2838 bp and a 432 bp 3'-UTR.The CcTLR22 protein was found to comprise a signal peptide, 16 LRR domains, a LRRCT domain in the extracellular region and a TIR domain in the cytoplasmic region, which fits with the characteristic TLR domain architecture. The genomic organization of CcTLR22 was identified, which was encoded by an uninterrupted exon. Sequence alignment and phylogenetic analysis showed that all known teleost TLR22 members were clustered into an independent clade of the TLR22 family, and showed high amino acid identities with other fish TLRs. Real-time PCR assay showed that CcTLR22 mRNA was expressed in almost all tissues examined, while the levels obviously varied among different tissues. When challenged with poly(I:C) (a viral model) or A. hydrophila bacteria, the expression level of CcTLR22 was up-regulated in a variety of common carp tissues. These results indicate that CcTLR22 plays a significant role in systemic as well as mucosal defence after viral or bacterial stimulation or infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

50 CFR 300.183 - Permit holder reporting and recordkeeping requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... information for each consignment of fish or fish products regulated under this subpart, except shark fins... biweekly report of entries for consumption, exports and re-exports of fish and fish products regulated under this subpart except shark fins. (1) The report required to be submitted under this paragraph (a...

mRNA-seq reveals skeletal muscle atrophy in response to handling stress in a marine teleost, the red cusk-eel (Genypterus chilensis).

PubMed

Aedo, Jorge E; Maldonado, Jonathan; Aballai, Víctor; Estrada, Juan M; Bastias-Molina, Macarena; Meneses, Claudio; Gallardo-Escarate, Cristian; Silva, Herman; Molina, Alfredo; Valdés, Juan A

2015-12-01

Fish reared under intensive conditions are repeatedly exposed to stress, which negatively impacts growth. Although most fish follow a conserved pattern of stress response, with increased concentrations of cortisol, each species presents specificities in the cell response and stress tolerance. Therefore, culturing new species requires a detailed knowledge of these specific responses. The red cusk-eel (Genypterus chilensis) is a new economically important marine species for the Chilean aquaculture industry. However, there is no information on the stress- and cortisol-induced mechanisms that decrease skeletal muscle growth in this teleost. Using Illumina RNA-seq technology, skeletal muscle sequence reads for G. chilensis were generated under control and handling stress conditions. Reads were mapped onto a reference transcriptome, resulting in the in silico identification of 785 up-regulated and 167 down-regulated transcripts. Gene ontology enrichment analysis revealed a significant up-regulation of catabolic genes associated with skeletal muscle atrophy. These results were validated by RT-qPCR analysis for ten candidates genes involved in ubiquitin-mediated proteolysis, autophagy and skeletal muscle growth. Additionally, using a primary culture of fish skeletal muscle cells, the effect of cortisol was evaluated in relation to red cusk-eel skeletal muscle atrophy. The present data demonstrated that handling stress promotes skeletal muscle atrophy in the marine teleost G. chilensis through the expression of components of the ubiquitin-proteasome and autophagy-lysosome systems. Furthermore, cortisol was a powerful inductor of skeletal muscle atrophy in fish myotubes. This study is an important step towards understanding the atrophy system in non-model teleost species and provides novel insights on the cellular and molecular mechanisms that control skeletal muscle growth in early vertebrates.

External and internal controls of lunar-related reproductive rhythms in fishes.

PubMed

Takemura, A; Rahman, M S; Park, Y J

2010-01-01

Reproductive activities of many fish species are, to some extent, entrained to cues from the moon. During the spawning season, synchronous spawning is repeated at intervals of c. 1 month (lunar spawning cycle) and 2 weeks (semi-lunar spawning cycle) or daily according to tidal changes (tidal spawning cycle). In species showing lunar-related spawning cycles, oocytes in the ovary develop towards and mature around a specific moon phase for lunar spawners, around spring tides for semi-lunar spawners and at daytime high tides for tidal spawners. The production of sex steroid hormones also changes in accordance with synchronous oocyte development. Since the production of the steroid hormones with lunar-related reproductive periodicity is regulated by gonadotropins, it is considered that the higher parts of the hypothalamus-pituitary-gonad axis play important roles in the perception and regulation of lunar-related periodicity. It is likely that fishes perceive cues from the moon by sensory organs; however, it is still unknown how lunar cues are transduced as an endogenous rhythm exerting lunar-related spawning rhythmicity. Recent research has revealed that melatonin fluctuated according to the brightness at night, magnetic fields and the tidal cycle. In addition, cyclic changes in hydrostatic pressure had an effect on monoamine contents in the brain. These factors may be indirectly related to the exertion of lunar-related periodicity. Molecular approaches have revealed that mRNA expressions of light-sensitive clock genes change with moonlight, suggesting that brightness at night plays a role in phase-shifting or resetting of biological clocks. Some species may have evolved biological clocks in relation to lunar cycles, although it is still not known how lunar periodicities are endogenously regulated in fishes. This review demonstrates that lunar-related periodicity is utilized and incorporated by ecological and physiological mechanisms governing the reproductive success of fishes.

Regulation of pregnane-X-receptor, CYP3A and P-glycoprotein genes in the PCB-resistant killifish (Fundulus heteroclitus) population from New Bedford Harbor.

PubMed

Gräns, Johanna; Wassmur, Britt; Fernández-Santoscoy, María; Zanette, Juliano; Woodin, Bruce R; Karchner, Sibel I; Nacci, Diane E; Champlin, Denise; Jayaraman, Saro; Hahn, Mark E; Stegeman, John J; Celander, Malin C

2015-02-01

Killifish survive and reproduce in the New Bedford Harbor (NBH) in Massachusetts (MA), USA, a site severely contaminated with polychlorinated biphenyls (PCBs) for decades. Levels of 22 different PCB congeners were analyzed in liver from killifish collected in 2008. Concentrations of dioxin-like PCBs in liver of NBH killifish were ∼400 times higher, and the levels of non-dioxin-like PCBs ∼3000 times higher than in killifish from a reference site, Scorton Creek (SC), MA. The NBH killifish are known to be resistant to the toxicity of dioxin-like compounds and to have a reduced aryl hydrocarbon receptor (AhR) signaling response. Little is known about the responses of these fish to non-dioxin-like PCBs, which are at extraordinarily high levels in NBH fish. In mammals, some non-dioxin-like PCB congeners act through nuclear receptor 1I2, the pregnane-X-receptor (PXR). To explore this pathway in killifish, a PXR cDNA was sequenced and its molecular phylogenetic relationship to other vertebrate PXRs was determined. Killifish were also collected in 2009 from NBH and SC, and after four months in the laboratory they were injected with a single dose of either the dioxin-like PCB 126 (an AhR agonist) or the non-dioxin-like PCB 153 (a mammalian PXR agonist). Gills and liver were sampled three days after injection and transcript levels of genes encoding PXR, cytochrome P450 3A (CYP3A), P-glycoprotein (Pgp), AhR2 and cytochrome P450 1A (CYP1A) were measured by quantitative PCR. As expected, there was little effect of PCB exposure on mRNA expression of AhR2 or CYP1A in liver and gills of NBH fish. In NBH fish, but not in SC fish, there was increased mRNA expression of hepatic PXR, CYP3A and Pgp upon exposure to either of the two PCB congeners. However, basal PXR and Pgp mRNA levels in liver of NBH fish were significantly lower than in SC fish. A different pattern was seen in gills, where there were no differences in basal mRNA expression of these genes between the two populations. In SC fish, but not in NBH fish, there was increased mRNA expression of branchial PXR and CYP3A upon exposure to PCB126 and of CYP3A upon exposure to PCB153. The results suggest a difference between the two populations in non-AhR transcription factor signaling in liver and gills, and that this could involve killifish PXR. It also implies possible cross-regulatory interactions between that factor (presumably PXR) and AhR2 in liver of these fish. Copyright © 2014 Elsevier B.V. All rights reserved.

Regulation of pregnane-X-receptor, CYP3A and P-glycoprotein genes in the PCB-resistant killifish (Fundulus heteroclitus) population from New Bedford Harbor1

PubMed Central

Gräns, Johanna; Wassmur, Britt; Fernández-Santoscoy, María; Zanette, Juliano; Woodin, Bruce R.; Karchner, Sibel I.; Nacci, Diane E.; Champlin, Denise; Jayaraman, Saro; Hahn, Mark E.; Stegeman, John J.; Celander, Malin C.

2015-01-01

Killifish survive and reproduce in the New Bedford Harbor (NBH) in Massachusetts (MA), USA, a site severely contaminated with polychlorinated biphenyls (PCBs) for decades. Levels of 22 different PCB congeners were analyzed in liver from killifish collected in 2008. Concentrations of dioxin-like PCBs in liver of NBH killifish were ~400 times higher, and the levels of non-dioxin-like PCBs ~3000 times higher than in killifish from a reference site, Scorton Creek (SC), MA. The NBH killifish are known to be resistant to the toxicity of dioxin-like compounds and to have a reduced aryl hydrocarbon receptor (AhR) signaling response. Little is known about the responses of these fish to non-dioxin-like PCBs, which are at extraordinarily high levels in NBH fish. In mammals, some non-dioxin-like PCB congeners act through nuclear receptor 1I2, the pregnane-X-receptor (PXR). To explore this pathway in killifish, a PXR cDNA was sequenced and its molecular phylogenetic relationship to other vertebrate PXRs was determined. Killifish were also collected in 2009 from NBH and SC, and after four months in the laboratory they were injected with a single dose of either the dioxin-like PCB 126 (an AhR agonist) or the non-dioxin-like PCB 153 (a mammalian PXR agonist). Gills and liver were sampled three days after injection and transcript levels of genes encoding PXR, cytochrome P450 3A (CYP3A), P-glycoprotein (Pgp), AhR2 and cytochrome P450 1A (CYP1A) were measured by quantitative PCR. As expected, there was little effect of PCB exposure on mRNA expression of AhR2 or CYP1A in liver and gills of NBH fish. In NBH fish, but not in SC fish, there was increased mRNA expression of hepatic PXR, CYP3A and Pgp upon exposure to either of the two PCB congeners. However, basal PXR and Pgp mRNA levels in liver of NBH fish were significantly lower than in SC fish. A different pattern was seen in gills, where there were no differences in basal mRNA expression of these genes between the two populations. In SC fish, but not in NBH fish, there was increased mRNA expression of branchial PXR and CYP3A upon exposure to PCB126 and of CYP3A upon exposure to PCB153. The results suggest a difference between the two populations in non-AhR transcription factor signaling in liver and gills, and that this could involve killifish PXR. It also implies possible cross-regulatory interactions between that factor (presumably PXR) and AhR2 in liver of these fish. PMID:25553538

Modulation of Atlantic salmon miRNome response to sea louse infestation.

PubMed

Valenzuela-Muñoz, Valentina; Novoa, Beatriz; Figueras, Antonio; Gallardo-Escárate, Cristian

2017-11-01

MicroRNAs are non-coding RNA that plays a crucial role in post-transcriptional regulation and immune system regulation. On other hand, sea lice are prevalent parasites that affect salmon farming, generating different degrees of immune suppression depending on the salmon and sea louse species. Caligus rogercresseyi for example, which affects the salmon industry in Chile, decreases Th1 response, macrophage activation, TLR-mediated response and iron regulation in infected fish. In this study, we explore Atlantic salmon miRNome during infestation by C. rogercresseyi. Using small RNA sequencing, we annotated 1718 miRNAs for skin and head kidney from infected Atlantic salmon. The most abundant families identified were mir-10, mir-21, mir-30, mir-181 and let7. Significant differences were found between tissue, with 1404 annotated miRNA in head kidney and 529 in skin. Differential analysis of transcript expression indicated that at an early stage of infestation miRNA expression was higher in head kidney than in skin tissue, revealing tissue-specific expression patterns. In parallel, miRNA target prediction using 3'UTRs from highly regulated immune-related genes and iron metabolism showed that mir-140-4 and mir-181a-2-5 modulate the expression of TLR22 and Aminolevulinic acid synthase, respectively. This study contributes knowledge about the immune response of Atlantic salmon during infestation with sea lice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gene Expression Networks Underlying Ovarian Development in Wild Largemouth Bass (Micropterus salmoides)

PubMed Central

Martyniuk, Christopher J.; Prucha, Melinda S.; Doperalski, Nicholas J.; Antczak, Philipp; Kroll, Kevin J.; Falciani, Francesco; Barber, David S.; Denslow, Nancy D.

2013-01-01

Background Oocyte maturation in fish involves numerous cell signaling cascades that are activated or inhibited during specific stages of oocyte development. The objectives of this study were to characterize molecular pathways and temporal gene expression patterns throughout a complete breeding cycle in wild female largemouth bass to improve understanding of the molecular sequence of events underlying oocyte maturation. Methods Transcriptomic analysis was performed on eight morphologically diverse stages of the ovary, including primary and secondary stages of oocyte growth, ovulation, and atresia. Ovary histology, plasma vitellogenin, 17β-estradiol, and testosterone were also measured to correlate with gene networks. Results Global expression patterns revealed dramatic differences across ovarian development, with 552 and 2070 genes being differentially expressed during both ovulation and atresia respectively. Gene set enrichment analysis (GSEA) revealed that early primary stages of oocyte growth involved increases in expression of genes involved in pathways of B-cell and T-cell receptor-mediated signaling cascades and fibronectin regulation. These pathways as well as pathways that included adrenergic receptor signaling, sphingolipid metabolism and natural killer cell activation were down-regulated at ovulation. At atresia, down-regulated pathways included gap junction and actin cytoskeleton regulation, gonadotrope and mast cell activation, and vasopressin receptor signaling and up-regulated pathways included oxidative phosphorylation and reactive oxygen species metabolism. Expression targets for luteinizing hormone signaling were low during vitellogenesis but increased 150% at ovulation. Other networks found to play a significant role in oocyte maturation included those with genes regulated by members of the TGF-beta superfamily (activins, inhibins, bone morphogenic protein 7 and growth differentiation factor 9), neuregulin 1, retinoid X receptor, and nerve growth factor family. Conclusions This study offers novel insight into the gene networks underlying vitellogenesis, ovulation and atresia and generates new hypotheses about the cellular pathways regulating oocyte maturation. PMID:23527095

Interactome of E. piscicida and grouper liver proteins reveals strategies of bacterial infection and host immune response.

PubMed

Li, Hui; Zhu, Qing-Feng; Peng, Xuan-Xian; Peng, Bo

2017-01-03

The occurrence of infectious diseases is related to heterogeneous protein interactions between a host and a microbe. Therefore, elucidating the host-pathogen interplay is essential. We previously revealed the protein interactome between Edwardsiella piscicida and fish gill cells, and the present study identified the protein interactome between E. piscicida and E. drummondhayi liver cells. E. drummondhayi liver cells and bacterial pull-down approaches were used to identify E. piscicida outer membrane proteins that bind to liver cells and fish liver cell proteins that interact with bacterial cells, respectively. Eight bacterial proteins and 11 fish proteins were characterized. Heterogeneous protein-protein interactions between these bacterial cells and fish liver cells were investigated through far-Western blotting and co-immunoprecipitation. A network was constructed based on 42 heterogeneous protein-protein interactions between seven bacterial proteins and 10 fish proteins. A comparison of the new interactome with the previously reported interactome showed that four bacterial proteins overlapped, whereas all of the identified fish proteins were new, suggesting a difference between bacterial tricks for evading host immunity and the host strategy for combating bacterial infection. Furthermore, these bacterial proteins were found to regulate the expression of host innate immune-related proteins. These findings indicate that the interactome contributes to bacterial infection and host immunity.

78 FR 58753 - 2013-2014 Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-24

... pertinent refuge-specific regulations on other refuges that pertain to migratory game bird hunting, upland game hunting, big game hunting, and sport fishing for the 2013-2014 season. DATES: We will accept... migratory game bird hunting, upland game hunting, big game hunting, or sport fishing. These regulations list...

The Astonishing Diversity of Ig Classes and B Cell Repertoires in Teleost Fish

PubMed Central

Fillatreau, Simon; Six, Adrien; Magadan, Susanna; Castro, Rosario; Sunyer, J. Oriol; Boudinot, Pierre

2013-01-01

With lymphoid tissue anatomy different than mammals, and diverse adaptations to all aquatic environments, fish constitute a fascinating group of vertebrate to study the biology of B cell repertoires in a comparative perspective. Fish B lymphocytes express immunoglobulin (Ig) on their surface and secrete antigen-specific antibodies in response to immune challenges. Three antibody classes have been identified in fish, namely IgM, IgD, and IgT, while IgG, IgA, and IgE are absent. IgM and IgD have been found in all fish species analyzed, and thus seem to be primordial antibody classes. IgM and IgD are normally co-expressed from the same mRNA through alternative splicing, as in mammals. Tetrameric IgM is the main antibody class found in serum. Some species of fish also have IgT, which seems to exist only in fish and is specialized in mucosal immunity. IgM/IgD and IgT are expressed by two different sub-populations of B cells. The tools available to investigate B cell responses at the cellular level in fish are limited, but the progress of fish genomics has started to unravel a rich diversity of IgH and immunoglobulin light chain locus organization, which might be related to the succession of genome remodelings that occurred during fish evolution. Moreover, the development of deep sequencing techniques has allowed the investigation of the global features of the expressed fish B cell repertoires in zebrafish and rainbow trout, in steady state or after infection. This review provides a description of the organization of fish Ig loci, with a particular emphasis on their heterogeneity between species, and presents recent data on the structure of the expressed Ig repertoire in healthy and infected fish. PMID:23408183

Development of an oligo DNA microarray for the European sea bass and its application to expression profiling of jaw deformity

PubMed Central

2010-01-01

Background The European sea bass (Dicentrarchus labrax) is a marine fish of great importance for fisheries and aquaculture. Functional genomics offers the possibility to discover the molecular mechanisms underlying productive traits in farmed fish, and a step towards the application of marker assisted selection methods in this species. To this end, we report here on the development of an oligo DNA microarray for D. labrax. Results A database consisting of 19,048 unique transcripts was constructed, of which 12,008 (63%) could be annotated by similarity and 4,692 received a GO functional annotation. Two non-overlapping 60mer probes were designed for each unique transcript and in-situ synthesized on glass slides using Agilent SurePrint™ technology. Probe design was positively completed for 19,035 target clusters; the oligo microarray was then applied to profile gene expression in mandibles and whole-heads of fish affected by prognathism, a skeletal malformation that strongly affects sea bass production. Statistical analysis identified 242 transcripts that are significantly down-regulated in deformed individuals compared to normal fish, with a significant enrichment in genes related to nervous system development and functioning. A set of genes spanning a wide dynamic range in gene expression level were selected for quantitative RT-PCR validation. Fold change correlation between microarray and qPCR data was always significant. Conclusions The microarray platform developed for the European sea bass has a high level of flexibility, reliability, and reproducibility. Despite the well known limitations in achieving a proper functional annotation in non-model species, sufficient information was obtained to identify biological processes that are significantly enriched among differentially expressed genes. New insights were obtained on putative mechanisms involved on mandibular prognathism, suggesting that bone/nervous system development might play a role in this phenomenon. PMID:20525278

Molecular characterization of five steroid receptors from pengze crucian carp and their expression profiles of juveniles in response to 17α-ethinylestradiol and 17α-methyltestosterone.

PubMed

Zheng, Yao; Wang, Lihong; Li, Meng; Liang, Hongwei; Qin, Fang; Liu, Shaozhen; Wang, Houpeng; Wu, Tingting; Zhang, Yingying; Wang, Zaizhao

2013-09-15

Pengze crucian carp (Carassius auratus var. pengze, Pcc), a triploid gynogenetic fish, was used in this study to investigate the cross-talk between EDCs and steroid receptors. The full-length cDNAs of five steroid receptors (esr1, er alpha2, esr2a, esr2b, ar) and partial cDNA of vtg B were isolated. The tissue distributions of these genes were analyzed in adult fish by qRT-PCR. Then the expression profiles of five steroid receptors (esrs and ar) and vtg B were detected in the juveniles exposed to 17α-ethinylestradiol (EE2, 0.1, 1 and 10ng/L) and 17α-methyltestosterone (MT, 50μg/L) for 4weeks. The results demonstrated that esrs, ar, and vtg B were predominantly expressed in liver of adult fish. However, among these detected genes, esr1 and er alpha2 mRNAs are sensitive biomarkers in response to EE2 at 0.1, 1, and 10ng/L for 1 and 2weeks compared to esr2a, esr2b, ar, and vtg B in the juveniles of mono-female gynogenetic fish. Totally, the subtypes of esrs show biphasic responses to EE2 exposures for 4weeks, and most of the EE2 exposures at 0.1, 1, and 10ng/L for 1, 2, 3 and 4weeks did not induce the mRNA expressions of vtg B. However, 1-, 2-, and 4-week 50μg/L MT all significantly stimulated vtg B transcripts. Further investigations are needed to elucidate the mechanism underlying the insensitivity or down-regulation of vtg B mRNA in response to EE2 in juvenile Pcc. Copyright © 2013 Elsevier Inc. All rights reserved.

MicroRNA-20a is essential for normal embryogenesis by targeting vsx1 mRNA in fish

PubMed Central

Sun, Lei; Li, Heng; Xu, Xiaofeng; Xiao, Guanxiu; Luo, Chen

2015-01-01

MicroRNAs are major post-transcriptional regulators of gene expression and have essential roles in diverse developmental processes. In vertebrates, some regulatory genes play different roles at different developmental stages. These genes are initially transcribed in a wide embryonic region but restricted within distinct cell types at subsequent stages during development. Therefore, post-transcriptional regulation is required for the transition from one developmental stage to the next and the establishment of different cell identities. However, the regulation of many multiple functional genes at post-transcription level during development remains unknown. Here we show that miR-20a can target the mRNA of vsx1, a multiple functional gene, at the 3′-UTR and inhibit protein expression in both goldfish and zebrafish. The expression of miR-20a is initiated ubiquitously at late gastrula stage and exhibits a tissue-specific pattern in the developing retina. Inhibition of vsx1 3′-UTR mediated protein expression occurs when and where miR-20a is expressed. Decoying miR-20a resulted in severely impaired head, eye and trunk formation in association with excessive generation of vsx1 marked neurons in the spinal cord and defects of somites in the mesoderm region. These results demonstrate that miR-20a is essential for normal embryogenesis by restricting Vsx1 expression in goldfish and zebrafish, and that post-transcriptional regulation is an essential mechanism for Vsx1 playing different roles in diverse developmental processes. PMID:25833418

36 CFR 13.1146 - What other closures and restrictions apply to commercial fishermen and commercial fishing vessels?

Code of Federal Regulations, 2014 CFR

2014-07-01

... IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Commercial Fishing § 13.1146... Inlets. (b) Commercial fishing in the waters of the west arm of Glacier Bay north of 58° 50.0′ N latitude... fishing regulations. (c) Commercial fishing in the east arm of Glacier Bay, north of an imaginary line...

36 CFR 13.1146 - What other closures and restrictions apply to commercial fishermen and commercial fishing vessels?

Code of Federal Regulations, 2012 CFR

2012-07-01

... IN ALASKA Special Regulations-Glacier Bay National Park and Preserve Commercial Fishing § 13.1146... Inlets. (b) Commercial fishing in the waters of the west arm of Glacier Bay north of 58° 50.0′ N latitude... fishing regulations. (c) Commercial fishing in the east arm of Glacier Bay, north of an imaginary line...

Proteomic analysis of three gonad types of swamp eel reveals genes differentially expressed during sex reversal.

PubMed

Sheng, Yue; Zhao, Wei; Song, Ying; Li, Zhigang; Luo, Majing; Lei, Quan; Cheng, Hanhua; Zhou, Rongjia

2015-05-18

A variety of mechanisms are engaged in sex determination in vertebrates. The teleost fish swamp eel undergoes sex reversal naturally and is an ideal model for vertebrate sexual development. However, the importance of proteome-wide scanning for gonad reversal was not previously determined. We report a 2-D electrophoresis analysis of three gonad types of proteomes during sex reversal. MS/MS analysis revealed a group of differentially expressed proteins during ovary to ovotestis to testis transformation. Cbx3 is up-regulated during gonad reversal and is likely to have a role in spermatogenesis. Rab37 is down-regulated during the reversal and is mainly associated with oogenesis. Both Cbx3 and Rab37 are linked up in a protein network. These datasets in gonadal proteomes provide a new resource for further studies in gonadal development.

Hypothermal stress induced differential expression profiles of the immune response gene, warm-temperature-acclimation associated 65-kDa protein (Wap65), in the liver of fresh water and seawater milkfish, Chanos chanos.

PubMed

Chang, Chia-Hao; Lin, Jing-Yun; Lo, Wan-Yu; Lee, Tsung-Han

2017-11-01

The milkfish (Chanos chanos), an important aquaculture species, is intolerant to cold environments. Temperature fluctuations in the environment affect the physiological response, behavior, and survival rate of the fish. The warm-temperature-acclimation associated 65-kDa protein (Wap65) of teleosts was identified after heat shock treatment and has two isoforms. Both the isoforms were involved in the induction of immune responses in fish. They showed high degree of sequence conservation with the mammalian hemopexin and had high affinity for heme, which helped in the neutralization of free-heme and its transport to the liver. In this study, we isolated and characterized the two isoforms of wap65 genes (Ccwap65-1 and Ccwap65-2) from the liver of milkfish. The Ccwap65-1 and Ccwap65-2 are mainly expressed in livers of milkfish. In hypothermal treatment, the expression levels of Ccwap65-2 in the livers of SW and FW milkfish were up-regulated after exposure to low temperature (18 °C) for 12 h and 96 h compared to those in the normal temperature (28 °C) group, respectively. After intraperitoneal injection of lipopolysaccharide (LPS), the expression of Ccwap65-2 was elevated in both SW and FW milkfish, whereas that of Ccwap65-1 was not affected in both the groups. Thus, Ccwap65-2 expressed in the milkfish liver under hypothermal stress was identified as a novel immune biomarker. In addition, according to the transcriptome database, up-regulation of the other immune-response genes indicated increased pathogen infection status under hypothermal stress. Acute increase in the expression of hepatic Ccwap65-2 in response to pathogen infection might lead to better cold tolerance of SW milkfish compared to that of the FW individuals upon cold challenge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gene expression fingerprints of largemouth bass (Micropterus salmoides) exposed to pulp and paper mill effluents

USGS Publications Warehouse

Denslow, N.D.; Kocerha, J.; Sepulveda, M.S.; Gross, Timothy; Holm, S.E.

2004-01-01

Effluents from pulp and paper mills that historically have used elemental chlorine in the bleaching process have been implicated in inhibiting reproduction in fish. Compounds with estrogenic and androgenic binding affinities have been found in these effluents, suggesting that the impairment of reproduction is through an endocrine-related mode of action. To date, a great deal of attention has been paid to phytoestrogens and resin acids that are present in mill process streams as a result of pulping trees. Estrogen and estrogen mimics interact directly with the estrogen receptor and have near immediate effects on gene transcription by turning on the expression of a unique set of genes. Using differential display (DD) RT-PCR, we examined changes in gene expression induced by exposure to paper mill effluents. Largemouth bass were exposed to 0, 10, 20, 40, and 80% paper mill effluent concentrations in large flow-through tanks for varied periods of time including 7, 28 or 56 days. Plasma hormone levels in males and females and plasma vitellogenin (Vtg) in females decreased with dose and time. Measurements of changes in gene expression using DD RT-PCR suggest that the gene expression patterns of male fish do not change much with exposure, except for the induction of a few genes including CYP 1A, a protein that is induced through the action of the Ah receptor in response to dioxin and similar polyaromatic hydrocarbons. However, in the case of females, exposure to these effluents resulted in an up-regulation of CYP 1A that was accompanied by a generalized down-regulation of genes normally expressed during the reproductive season. These antiestrogenic changes are in agreement with previous studies in bass exposed to these effluents, and could result in decreased reproductive success in affected populations. ?? 2004 Elsevier B.V. All rights reserved.

TSCA Section 21 Petition Requesting EPA to Regulate Lead in Fishing Tackle

EPA Pesticide Factsheets

This petition requests EPA to promulgate regulations under section 6 of TSCA to protect the environment from fishing tackle containing lead including fishing weights, sinkers, lures, jigs, and/or other tackle.

Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species.

PubMed

Zheng, X; Seiliez, I; Hastings, N; Tocher, D R; Panserat, S; Dickson, C A; Bergot, P; Teale, A J

2004-10-01

Fish are the most important dietary source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), that have particularly important roles in human nutrition reflecting their roles in critical physiological processes. The objective of the study described here was to clone, functionally characterize and compare expressed fatty acid desaturase genes involved in the production of EPA and DHA in freshwater and marine teleost fish species. Putative fatty acid desaturase cDNAs were isolated and cloned from common carp (Cyprinus carpio) and turbot (Psetta maximus). The enzymic activities of the products of these cDNAs, together with those of cDNAs previously cloned from rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata), were determined by heterologous expression in the yeast Saccharomyces cerevisiae. The carp and turbot desaturase cDNAs included open reading frames (ORFs) of 1335 and 1338 base pairs, respectively, specifying proteins of 444 and 445 amino acids. The protein sequences possessed all the characteristic features of microsomal fatty acid desaturases, including three histidine boxes, two transmembrane regions, and N-terminal cytochrome b(5) domains containing the haem-binding motif, HPGG. Functional expression showed all four fish cDNAs encode basically unifunctional Delta6 fatty acid desaturase enzymes responsible for the first and rate-limiting step in the biosynthesis of HUFA from 18:3n-3 and 18:2n-6. All the fish desaturases were more active towards the n-3 substrate with 59.5%, 31.5%, 23.1% and 7.0% of 18:3n-3 being converted to 18:4n-3 in the case of turbot, trout, sea bream and carp, respectively. The enzymes also showed very low, probably physiologically insignificant, levels of Delta5 desaturase activity, but none of the products showed Delta4 desaturase activity. The cloning and characterization of desaturases from these fish is an important advance, as they are species in which there is a relative wealth of data on the nutritional regulation of fatty acid desaturation and HUFA synthesis, and between which substantive differences occur.

75 FR 24862 - Removing Regulations Implementing the Fish and Wildlife Conservation Act

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 83 [Docket No. FWS-R9-WSR-2010... and Wildlife Conservation Act AGENCY: Fish and Wildlife Service, Interior. ACTION: Proposed rule. SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to remove our regulations implementing...

Influences of Chlorella vulgaris dietary supplementation on growth performance, hematology, immune response and disease resistance in Oreochromis niloticus exposed to sub-lethal concentrations of penoxsulam herbicide.

PubMed

Galal, Azza A A; Reda, Rasha M; Abdel-Rahman Mohamed, Amany

2018-06-01

Little is known regarding the impact of penoxsulam, a fluorinated benzenesulfonamid rice herbicide, on Oreochromis niloticus (O. niloticus). Therefore, the current study was undertaken to highlight the effects of penoxsulam exposure on O. niloticus and to evaluate the advantages of Chlorella vulgaris (CV) dietary supplementation against the induced effects. The 96-h lethal concentration 50 (LC 50 ) penoxsulam value for O. niloticus was estimated at 8.948 mg/L by probit analysis in a static bioassay experiment. Next, 360 healthy fish were randomly allocated into 6 treatment groups. The T1 group served as the negative control and was fed a basal diet. The T2 group served as the positive control and was fed a basal diet supplemented with 10% CV. The fish in the T3 and T4 groups were exposed to 1/10 the 96-h LC 50 of penoxsulam (0.8948 mg/L) and were fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. The fish in the T5 and T6 groups were exposed to 1/5 the 96-h LC 50 of penoxsulam (1.7896 mg/L) and fed the basal diet alone or the basal diet supplemented with 10% CV, respectively. Sub-acute penoxsulam exposure significantly altered hematological indices, as well as compromised the fish's immune defense mechanisms, including the phagocytic percentage, phagocytic index, nitric oxide production, immunoglobulin M levels and lysozyme, anti-trypsin and bactericidal activities subsequently decreasing O. niloticus's resistance to the Aeromonus sobria challenge and increasing disease symptoms and the mortality rate. Furthermore, sub-chronic penoxsulam exposure markedly altered growth performance, oxidant/antioxidant status and liver status and down-regulated the expression of interleukin-1β (IL-1β) and tumor necrosis-α (TNF-α). Interestingly, incorporating 10% CV into the diet protects fish against sub-acute penoxsulam-induced immunotoxicity via improvement of immune responses that increases the resistance against bacterial infection. Further, it improved the growth performance, oxidant/antioxidant status, liver status and markedly up-regulated immune-related gene expression, IL-1β and TNF-α, in the spleens of fish sub-chronically exposed to penoxsulam. These outcomes showed that dietary CV supplementation can protect the commercially valuable freshwater fish O. niloticus against penoxsulam toxicity and may be a potential feed supplement for Nile tilapia in aquaculture. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mutations in the Katnb1 gene cause left-right asymmetry and heart defects.

PubMed

Furtado, Milena B; Merriner, D Jo; Berger, Silke; Rhodes, Danielle; Jamsai, Duangporn; O'Bryan, Moira K

2017-12-01

The microtubule-severing protein complex katanin is composed two subunits, the ATPase subunit, KATNA1, and the noncatalytic regulatory subunit, KATNB1. Recently, the Katnb1 gene has been linked to infertility, regulation of centriole and cilia formation in fish and mammals, as well as neocortical brain development. KATNB1 protein is expressed in germ cells in humans and mouse, mitotic/meiotic spindles and cilia, although the full expression pattern of the Katnb1 gene has not been described. Using a knockin-knockout mouse model of Katnb1 dysfunction we demonstrate that Katnb1 is ubiquitously expressed during embryonic development, although a stronger expression is seen in the crown cells of the gastrulation organizer, the murine node. Furthermore, null and hypomorphic Katnb1 gene mutations show a novel correlation between Katnb1 dysregulation and the development of impaired left-right signaling, including cardiac malformations. Katanin function is a critical regulator of heart development in mice. These findings are potentially relevant to human cardiac development. Developmental Dynamics 246:1027-1035, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

At least two expressed genes for transcription factors Pitx2 and Rpx are present in common carp and are upregulated during winter acclimatization.

PubMed

Kausel, G; Vera, T; Valenzuela, G; Lopez, M; Romero, A; Muller, M; Figueroa, J

2010-12-01

The mechanisms of seasonal acclimatization in eurythermal fish such as common carp are not fully understood. Here, we concentrate on the regulation of pituitary factors, as this organ was shown to be highly affected by seasonal changes. We cloned and sequenced two different cDNAs for each of the transcription factors Pitx2 and Rpx, known to play a role in pituitary development. We show that these genes are conserved throughout evolution, to different degrees depending on the specific domain considered. Finally, we show that the cDNAs for both factors are clearly up-regulated during the winter season, in sharp contrast to other regulators such as Pit1 or pituitary hormone genes such as prolactin (prl) and growth hormone (gh). Our results suggest that increased expression of Pitx2 and Rpx contributes to seasonal adaptation of common carp to winter conditions. Copyright © 2010 Elsevier Inc. All rights reserved.

Novel expression of the stanniocalcin gene in fish.

PubMed

McCudden, C R; Kogon, M R; DiMattia, G E; Wagner, G F

2001-10-01

It is currently accepted that the fish stanniocalcin (STC) gene is expressed exclusively in the corpuscles of Stannius (CS), unique endocrine glands on the kidneys of bony fishes. In this study, we have re-examined the pattern of fish STC gene expression in the light of the recent evidence for widespread expression of the gene in mammals. Surprisingly, we found by Northern blotting that the fish gene was also expressed in the kidneys and gonads, in addition to the CS glands. Moreover, Southern blotting of RT-PCR products revealed STC mRNA transcripts in all tissues assayed, including brain, heart, gill, muscle and intestine. In situ hybridization studies using digoxigenin-labeled riboprobes localized STC mRNA to chondrocytes, and both mature and developing nephritic tubules. Immunocytochemical staining indicated that the STC protein was widespread in cells of the gill, kidney, brain, eye, pseudobranch and skin. We also characterized the salmon STC gene, establishing that it was comprised of five exons as opposed to four in mammals. A single transcription start site was identified by primer extension 99 bp upstream of the start codon. This is the first evidence of STC gene expression in fish tissues other than the CS glands and suggests that, as in mammals, fish STC operates via both local and endocrine pathways.

The Presence or Absence of Intestinal Microbiota Affects Lipid Deposition and Related Genes Expression in Zebrafish (Danio rerio).

PubMed

Sheng, Yi; Ren, Hui; Limbu, Samwel M; Sun, Yuhong; Qiao, Fang; Zhai, Wanying; Du, Zhen-Yu; Zhang, Meiling

2018-01-01

Understanding how intestinal microbiota alters energy homeostasis and lipid metabolism is a critical process in energy balance and health. However, the exact role of intestinal microbiota in the regulation of lipid metabolism in fish remains unclear. Here, we used two zebrafish models (germ-free and antibiotics-treated zebrafish) to identify the role of intestinal microbiota in lipid metabolism. Conventional and germ-free zebrafish larvae were fed with egg yolk. Transmission electron microscopy was used to detect the presence of lipid droplets in the intestinal epithelium. The results showed that, microbiota increased lipid accumulation in the intestinal epithelium. The mRNA sequencing technology was used to assess genes expression level. We found majority of the differentially expressed genes were related to lipid metabolism. Due to the limitation of germ-free zebrafish larvae, antibiotics-treated zebrafish were also used to identify the relationship between the gut microbiota and the host lipid metabolism. Oil-red staining showed antibiotics-treated zebrafish had less intestinal lipid accumulation than control group. The mRNA expression of genes related to lipid metabolism in liver and intestine was also quantified by using real-time PCR. The results indicated that apoa4 , hsl , cox15 , slc2a1a , and lss were more related to intestinal bacteria in fish, while the influence of intestinal microbiota on the activity of fabp6 , acsl5 , cd36 , and gpat2 was different between the liver and intestine. This study identified several genes regulated by intestinal microbiota. Furthermore, the advantages and disadvantages of each model have been discussed. This study provides valuable information for exploring host-microbiota interactions in zebrafish in future.

Molecular cloning, expression pattern of follistatin gene and association analysis with growth traits in bighead carp (Hypophthalmichthys nobilis).

PubMed

Pang, Meixia; Tong, Jingou; Yu, Xiaomu; Fu, Beide; Zhou, Ying

2018-04-01

Follistatin (FST) is a single-chain gonadal protein involving in various biological effects. FST plays important roles in not only ovary development but also body growth, whereas myostatin (MSTN) negatively regulates muscle growth. In this study, FST gene in bighead carp (HynFST) was cloned and characterized. A 5797 bp genomic sequence of HynFST, consisting six exons and five introns were cloned. The full-length cDNA of HynFST (2134 bp) has an open reading fragment encoding a polypeptide of 349 amino acids. Sequence comparison and phylogenetic analysis confirmed that FSTs are conserved throughout the vertebrates and HynFST belongs to FST-1 isoform. Nine single nucleotide polymorphisms (SNPs) of the HynFST were identified and three of them (g.2443 T > C, g.2852 T > C and g.5483A > G) were significantly associated with four growth-related traits. The average body weight of those fish with the combined genotype (CC CC GG) was 12.15-22.63% higher than that of triplotype (TT TT AA) in two bighead carp populations. HynFST was expressed in most of the development stages and various tissues with highest level in ovary. The co-expression results for FST and MSTN in brain and muscle of divergent weight groups showed that FST may inhibit MSTN expression, thus enhancing growth in bighead carp. Our results suggest that FST has significant genetic effects on the regulation of early growth in bighead carp. This study would facilitate the elucidation of multiple functions of FST gene in fish and exploration of the potentials as a gene marker in selective breeding programs for growth of bighead carp. Copyright © 2018 Elsevier Inc. All rights reserved.

Differential expression of Na+, K(+)-ATPase α-1 isoforms during seawater acclimation in the amphidromous galaxiid fish Galaxias maculatus.

PubMed

Urbina, Mauricio A; Schulte, Patricia M; Bystriansky, Jason S; Glover, Chris N

2013-04-01

Inanga (Galaxias maculatus) is an amphidromous fish with a well-known capacity to withstand a wide range of environmental salinities. To investigate the molecular mechanisms facilitating acclimation of inanga to seawater, several isoforms of the Na(+), K(+)-ATPase ion transporter were identified. This included three α-1 (a, b and c), an α-2 and two α-3 (a and b) isoforms. Phylogenetic analysis showed that the inanga α-1a and α-1b formed a clade with the α-1a and α-1b isoforms of rainbow trout, while another clade contained the α-1c isoforms of these species. The expression of all the α-1 isoforms was modulated after seawater exposure (28‰). In gills, the expression of the α-1a isoform was progressively down-regulated after seawater exposure, while the expression of the α-1b isoform was up-regulated. The α-1c isoform behaved similarly to the α-1a, although changes were less dramatic. Physiological indicators of salinity acclimation matched the time frame of the changes observed at the molecular level. A 24-h osmotic shock period was highlighted by small increases in plasma osmolality, plasma Na(+) and a decrease in muscle tissue water content. Thereafter, these values returned close to their pre-exposure (freshwater) values. Na(+), K(+)-ATPase activity showed a decreasing trend over the first 72 h following seawater exposure, but activity increased after 240 h. Our results indicate that inanga is an excellent osmoregulator, an ability that is conferred by the rapid activation of physiological and molecular responses to salinity change.

Detoxification and antioxidant effects of garlic and curcumin in Oreochromis niloticus injected with aflatoxin B₁ with reference to gene expression of glutathione peroxidase (GPx) by RT-PCR.

PubMed

El-Barbary, Manal I

2016-04-01

The present study aims to investigate the effects of both garlic and curcumin through evaluating their therapeutic properties as antioxidants on liver and kidney functions, hepatic antioxidants and GPx gene expression against aflatoxicosis of O. niloticus. In total, 180 of tilapia were divided into ten groups; T1 represented the negative control fed on a basal diet, and T2 was injected with a single intraperitoneal (i.p.) dose of AFB1 (6 mg/kg b.w.). Fish in T3-T6 were fed on a basal diet supplemented with both garlic (T3 and T4) and curcumin (T5 and T6) at the two concentrations of 10 and 20 g/kg diet, respectively. Fish in T7-T10 groups were injected with AFB1 and fed on the garlic (T7 and T8) and curcumin (T9 and T10) dietaries. The results showed that AFB1 has significant potency for increasing the activity of plasma AST, ALT, creatinine and uric acid values, and hepatic MDA as well as for reducing the concentrations of plasma TP, AL, GL and hepatic activity of TAC, while AFB1 led to up-regulated GPx gene expression when compared to the control (T1). These harmful effects of AFB1 were alleviated due to the garlic and curcumin dietaries in some studied parameters. Garlic reflected the highest induction of gene expression (T7); however, curcumin showed significant down-regulated (T9). These results concluded that the effects of garlic were better than curcumin at the two concentrations and the low concentration of them is more beneficial than the high concentration when it used against AFB1 in O. niloticus.

Salinity-induced regulation of the myo-inositol biosynthesis pathway in tilapia gill epithelium

PubMed Central

Sacchi, Romina; Li, Johnathon; Villarreal, Fernando; Gardell, Alison M.; Kültz, Dietmar

2013-01-01

SUMMARY The myo-inositol biosynthesis (MIB) pathway converts glucose-6-phosphate to the compatible osmolyte myo-inositol that protects cells from osmotic stress. Using proteomics, the enzymes that constitute the MIB pathway, myo-inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPA1), are identified in tilapia (Oreochromis mossambicus) gill epithelium. Targeted, quantitative, label-free proteomics reveals that they are both upregulated during salinity stress. Upregulation is stronger when fish are exposed to severe (34 ppt acute and 90 ppt gradual) relative to moderate (70 ppt gradual) salinity stress. IMPA1 always responds more strongly than MIPS, suggesting that MIPS is more stable during salinity stress. MIPS is N-terminally acetylated and the corresponding peptide increases proportionally to MIPS protein, while non-acetylated N-terminal peptide is not detectable, indicating that MIPS acetylation is constitutive and may serve to stabilize the protein. Hyperosmotic induction of MIPS and IMPA1 is confirmed using western blot and real-time qPCR and is much higher at the mRNA than at the protein level. Two distinct MIPS mRNA variants are expressed in the gill, but one is more strongly regulated by salinity than the other. A single MIPS gene is encoded in the tilapia genome whereas the zebrafish genome lacks MIPS entirely. The genome of euryhaline tilapia contains four IMPA genes, two of which are expressed, but only one is salinity regulated in gill epithelium. The genome of stenohaline zebrafish contains a single IMPA gene. We conclude that the MIB pathway represents a major salinity stress coping mechanism that is regulated at multiple levels in euryhaline fish but absent in stenohaline zebrafish. PMID:24072791

77 FR 58050 - Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 32 Refuge-Specific Hunting and Sport Fishing Regulations CFR Correction Sec. 32.37 [Corrected] 0 In Title 50 of the Code of Federal Regulations, Parts 18 to 199, revised as of October 1, 2011, on page 345, in Sec. 32.37, under Black Bayou...

77 FR 58050 - Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 32 Refuge-Specific Hunting and Sport Fishing Regulations CFR Correction Sec. 32.29 [Corrected] 0 In Title 50 of the Code of Federal Regulations, parts 18 to 199, revised as of October 1, 2011, on page 320, in Sec. 32.29, under Savannah...

77 FR 58051 - Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-19

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 32 Refuge-Specific Hunting and Sport Fishing Regulations CFR Correction 0 In Title 50 of the Code of Federal Regulations, Parts 18 to 199, revised as of October 1, 2011, on page 410, in Sec. 32.44, the entry for Middle Mississippi River...

Effects of growth hormone over-expression on reproduction in the common carp Cyprinus carpio L.

PubMed

Cao, Mengxi; Chen, Ji; Peng, Wei; Wang, Yaping; Liao, Lanjie; Li, Yongming; Trudeau, Vance L; Zhu, Zuoyan; Hu, Wei

2014-01-01

To study the complex interaction between growth and reproduction we have established lines of transgenic common carp (Cyprinus carpio) carrying a grass carp (Ctenopharyngodon idellus) growth hormone (GH) transgene. The GH-transgenic fish showed delayed gonadal development compared with non-transgenic common carp. To gain a better understanding of the phenomenon, we studied body growth, gonad development, changes of reproduction related genes and hormones of GH-transgenic common carp for 2years. Over-expression of GH elevated peripheral gh transcription, serum GH levels, and inhibited endogenous GH expression in the pituitary. Hormone analyses indicated that GH-transgenic common carp had reduced pituitary and serum level of luteinizing hormone (LH). Among the tested genes, pituitary lhβ was inhibited in GH-transgenic fish. Further analyses in vitro showed that GH inhibited lhβ expression. Localization of ghr with LH indicates the possibility of direct regulation of GH on gonadotrophs. We also found that GH-transgenic common carp had reduced pituitary sensitivity to stimulation by co-treatments with a salmon gonadotropin-releasing hormone (GnRH) agonist and a dopamine antagonist. Together these results suggest that the main cause of delayed reproductive development in GH transgenic common carp is reduced LH production and release. Copyright © 2013 Elsevier Inc. All rights reserved.

Beta-glucan enhances the response to SVCV infection in zebrafish.

PubMed

M Medina-Gali, Regla; Ortega-Villaizan, María Del Mar; Mercado, Luis; Novoa, Beatriz; Coll, Julio; Perez, Luis

2018-07-01

The antiviral effects of beta-glucan, an immunostimulatory agent were studied in zebrafish both in vitro and in vivo. Here we show that zebrafish ZF4 cells as well as whole fish primed with yeast β-glucan zymosan exhibited increased cytokine expression and elevated response to spring viremia of carp virus (SVCV) infection. In vitro, previous treatment of β-glucan enhanced ZF4 cell viability against SVCV infection which is associated to the activation of interferon signaling pathway and inflammatory cytokines gene expression. In vivo, the SVCV-infected fish primed with β-glucan had a higher survival rate (≈73%) than the control SVCV-infected group (≈33%). Additionally, up-regulation of the expression of a set of genes involved in innate immune response was detected in zebrafish intraperitoneally injected of β-glucan: il1b, il6, il8, il10 and tnfa transcripts showed increased expression that appear to be rapid (2 days) but not long-lived (less than 2 weeks). The present study is, to our knowledge, the first to combine cell culture and in vivo approaches to describe host response to β-glucan stimulation and viral infection in zebrafish. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transcriptomics of mRNA and egg quality in farmed fish: Some recent developments and future directions.

PubMed

Sullivan, Craig V; Chapman, Robert W; Reading, Benjamin J; Anderson, Paul E

2015-09-15

Maternal mRNA transcripts deposited in growing oocytes regulate early development and are under intensive investigation as determinants of egg quality. The research has evolved from single gene studies to microarray and now RNA-Seq analyses in which mRNA expression by virtually every gene can be assessed and related to gamete quality. Such studies have mainly focused on genes changing two- to several-fold in expression between biological states, and have identified scores of candidate genes and a few gene networks whose functioning is related to successful development. However, ever-increasing yields of information from high throughput methods for detecting transcript abundance have far outpaced progress in methods for analyzing the massive quantities of gene expression data, and especially for meaningful relation of whole transcriptome profiles to gamete quality. We have developed a new approach to this problem employing artificial neural networks and supervised machine learning with other novel bioinformatics procedures to discover a previously unknown level of ovarian transcriptome function at which minute changes in expression of a few hundred genes is highly predictive of egg quality. In this paper, we briefly review the progress in transcriptomics of fish egg quality and discuss some future directions for this field of study. Copyright © 2015 Elsevier Inc. All rights reserved.

The leptin system and its expression at different nutritional and pregnant stages in lined seahorse (Hippocampus erectus).

PubMed

Zhang, Huixian; Qin, Geng; Zhang, Yanhong; Li, Shuisheng; Lin, Qiang

2016-10-15

Leptin is an essential hormone for the regulation of energy metabolism and food intake in vertebrate animals. To better understand the physiological roles of leptin in nutrient regulation in paternal ovoviviparous fish (family Syngnathidae), the present study cloned the full-length of leptin-a and leptin receptor (lepr) genes in lined seahorse (Hippocampus erectus). Results showed that there was a 576-bp intron between two exons in leptin-a gene but no leptin-b gene in seahorse. Although the primary amino acid sequence conservation of seahorse leptin-a was very low, the 3-D structure modeling of seahorse leptin-a revealed strong conservation of tertiary structure with other vertebrates. Seahorse leptin-a mRNA was highly expressed in brain, whereas lepr mRNA was mainly expressed in ovary and gill. Interestingly, both leptin-a and lepr mRNA were expressed in the brood pouch of male seahorse, suggesting the leptin system plays a role during the male pregnancy. Physiological experiments showed that the expression of hepatic leptin-a and lepr mRNA in unfed seahorses was significantly higher than that in those fed 100%, as well as 60%, of their food during the fasting stage, showing that seahorse might initiate the leptin system to regulate its energy metabolism while starving. Moreover, the expression of leptin-a in the brood pouch of pregnant seahorse was significantly upregulated compared with non-pregnant seahorse, whereas the expression of lepr was downregulated, suggesting that the leptin system might be involved in the male pregnancy. In conclusion, the leptin system plays a role in the energy metabolism and food intake, and might provide new insights into molecular regulation of male pregnancy in seahorse. © 2016. Published by The Company of Biologists Ltd.

The leptin system and its expression at different nutritional and pregnant stages in lined seahorse (Hippocampus erectus)

PubMed Central

Zhang, Huixian; Qin, Geng; Zhang, Yanhong; Li, Shuisheng

2016-01-01

ABSTRACT Leptin is an essential hormone for the regulation of energy metabolism and food intake in vertebrate animals. To better understand the physiological roles of leptin in nutrient regulation in paternal ovoviviparous fish (family Syngnathidae), the present study cloned the full-length of leptin-a and leptin receptor (lepr) genes in lined seahorse (Hippocampus erectus). Results showed that there was a 576-bp intron between two exons in leptin-a gene but no leptin-b gene in seahorse. Although the primary amino acid sequence conservation of seahorse leptin-a was very low, the 3-D structure modeling of seahorse leptin-a revealed strong conservation of tertiary structure with other vertebrates. Seahorse leptin-a mRNA was highly expressed in brain, whereas lepr mRNA was mainly expressed in ovary and gill. Interestingly, both leptin-a and lepr mRNA were expressed in the brood pouch of male seahorse, suggesting the leptin system plays a role during the male pregnancy. Physiological experiments showed that the expression of hepatic leptin-a and lepr mRNA in unfed seahorses was significantly higher than that in those fed 100%, as well as 60%, of their food during the fasting stage, showing that seahorse might initiate the leptin system to regulate its energy metabolism while starving. Moreover, the expression of leptin-a in the brood pouch of pregnant seahorse was significantly upregulated compared with non-pregnant seahorse, whereas the expression of lepr was downregulated, suggesting that the leptin system might be involved in the male pregnancy. In conclusion, the leptin system plays a role in the energy metabolism and food intake, and might provide new insights into molecular regulation of male pregnancy in seahorse. PMID:27628034

Sexually dimorphic expression of gonadotropin subunits in the pituitary of protogynous honeycomb grouper (Epinephelus merra): evidence that follicle-stimulating hormone (FSH) induces gonadal sex change.

PubMed

Kobayashi, Yasuhisa; Alam, Mohammad Ashraful; Horiguchi, Ryo; Shimizu, Akio; Nakamura, Masaru

2010-06-01

Recent studies have suggested that the hypothalamic-pituitary-gonadal axis is involved in gonadal sex change in sex-changing teleosts. However, its underlying mechanism remains largely unknown. In this study, we focused on the distinct roles of two gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), in the protogynous hermaphrodite teleost, honeycomb grouper (Epinephelus merra). First, we investigated the expression pattern of mRNAs for GTH subunits (cga, fshb, and lhb) in the pituitaries from fish at the different sexual phases. Real-time RT-PCR analyses showed that fhsb mRNA levels in the female pituitary were low. However, fshb transcripts increased dramatically in association with testis development. In contrast, levels of cga and lhb mRNAs did not significantly vary during sex change. In addition, immunohistochemical observations of Fshb- and Lhb-producing cells in the pituitary, through the use of specific antibodies for detections of teleost GTH subunits, were consistent with sexually dimorphic expression of Fshb. In order to identify the role of GTH in gonad of honeycomb grouper, we treated females with bovine FSH (50 or 500 ng/fish) or LH (500 ng/fish) in vivo. After 3 wk, FSH treatments induced female-to-male sex change and up-regulated endogenous androgen levels and fshb transcripts, whereas LH treatment had no effect on sex change. These results suggest that FSH may trigger the female-to-male sex change in honeycomb grouper.

Isolation and expression analysis of FTZ-F1 encoding gene of black rock fish ( Sebastes schlegelii)

NASA Astrophysics Data System (ADS)

Shafi, Muhammad; Wang, Yanan; Zhou, Xiaosu; Ma, Liman; Muhammad, Faiz; Qi, Jie; Zhang, Quanqi

2013-03-01

Sex related FTZ-F1 is a transcriptional factor regulating the expression of fushi tarazu (a member of the orphan nuclear receptors) gene. In this study, FTZ-F1 gene ( FTZ-F1) was isolated from the testis of black rockfish ( Sebastes schlegeli) by homology cloning. The full-length cDNA of S. schlegeli FTZ-F1 ( ssFTZ-F1) contained a 232bp 5' UTR, a 1449bp ORF encoding FTZ-F1 (482 amino acid residules in length) with an estimated molecular weight of 5.4kD and a 105bp 3' UTR. Sequence, tissue distribution and phylogenic analysis showed that ssFTZ-F1 belonged to FTZ group, holding highly conserved regions including I, II and III FTZ-F1 boxes and an AF-2 hexamer. Relatively high expression was observed at different larva stages. In juveniles (105 days old), the transcript of ssFTZ-F1 can be detected in all tissues and the abuncance of the gene transcript in testis, ovary, spleen and brain was higher than that in other tissues. In mature fish, the abundance of gene transcript was higher in testis, ovary, spleen and brain than that in liver (trace amount), and the gene was not transcribed in other tissues. The highest abundance of gene transcript was always observed in gonads of both juvenile and mature fish. In addition, the abundance of gene transcript in male tissues were higher than that in female tissue counterparts ( P<0.05).

Expression profiles of three types of GnRH during sex-change in the protandrous cinnamon clownfish, Amphiprion melanopus: Effects of exogenous GnRHs.

PubMed

Kim, Na Na; Shin, Hyun Suk; Habibi, Hamid R; Lee, Jehee; Choi, Cheol Young

2012-02-01

Gonadotropin-releasing hormones (GnRHs) play pivotal roles in the control of reproduction and gonadal maturation in teleost fish. Fish have multiple GnRH genes that encode structurally distinct peptides. We identified salmon GnRH (sGnRH), seabream GnRH (sbGnRH), and chicken GnRH-II (cGnRH-II) by cDNA cloning in cinnamon clownfish (Amphiprion melanopus) using reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends-PCR (RACE-PCR). Gene identity was confirmed by sequence alignment and subsequent phylogenetic analyses. We also investigated GnRH mRNA expression in the gonads by quantitative real time-PCR (Q-PCR), and measured plasma estradiol-17β (E(2)) levels in immature fish following treatment with the three molecular forms of GnRHs. The expression levels of sGnRH, sbGnRH, and cGnRH-II mRNA were higher in mature testes and ovaries, as compared to the levels in gonads at earlier stages of maturity. The levels of the three prepro-GnRH mRNA species and the plasma E(2) levels increased after injection of the three GnRH variants. These findings support the hypothesis that GnRH peptides play important roles in the regulation of the hypothalamic-pituitary-gonadal axis and are probably involved in paracrine control of gonadal development and sex change in cinnamon clownfish. Copyright © 2011 Elsevier Inc. All rights reserved.

Polyunsaturated fatty acids ameliorate aging via redox-telomere-antioncogene axis.

PubMed

Chen, Jingnan; Wei, Yan; Chen, Xinyu; Jiao, Jingjing; Zhang, Yu

2017-01-31

Polyunsaturated fatty acids (PUFA), a group of nourishing and health-promoting nutrients, ameliorate age-related chronic diseases. However, how PUFA especially n-3 PUFA exert anti-aging functions remains poorly understood. Here we link fish oil, docosahexaenoic acid (DHA) and arachidonic acid (AA) to the aging etiology via a redox-telomere-antioncogene axis based on D-galactose-induced aging mice. Both fish oil and PUFA enhanced hepatic superoxide dismutase (SOD) and catalase activities and cardiac SOD activities within the range of 18%-46%, 26%-65% and 19%-58%, respectively, whereas reduced cerebral monoamine oxidase activity, plasma F2-isoprostane level and cerebral lipid peroxidation level by 56%-90%, 20%-79% and 16%-54%, respectively. Thus, PUFA improve the in vivo redox and oxidative stress induced aging process, which however does not exhibit a dose-dependent manner. Notably, both PUFA and fish oil effectively inactivated testicular telomerase and inhibited c-Myc-mediated telomerase reverse transcriptase expression, whereas n-3 PUFA rather than n-6 PUFA protected liver and testes against telomere shortening within the range of 13%-25% and 25%-27%, respectively. Therefore, n-3 PUFA may be better at inhibiting the DNA damage induced aging process. Surprisingly, only DHA significantly suppressed cellular senescence pathway evidenced by testicular antioncogene p16 and p53 expression. This work provides evident support for the crosstalk between PUFA especially n-3 PUFA and the aging process via maintaining the in vivo redox homeostasis, rescuing age-related telomere attrition and down-regulating the antioncogene expression.

2, 4-Dichloro-6-nitrophenol, a photonitration product of 2, 4-dichlorophenol, caused anti-androgenic potency in Chinese rare minnows (Gobiocypris rarus).

PubMed

Chen, Rui; Liu, Cao; Yuan, Lilai; Zha, Jinmiao; Wang, Zijian

2016-09-01

2,4-Dichloro-6-nitrophenol (DCNP) is an environmental transformation product of 2,4-dichlorophenol that has been identified as widespread in effluent wastewater, but little is known about its toxicity because this compound is not regulated. Therefore, to investigate the endocrine disruption potency of DCNP in Chinese rare minnows (Gobiocypris rarus), adult and juvenile fish were exposed to various concentrations of DCNP (2, 20, and 200 μg/L) for 28 d. After 28 d exposure, the plasma vitellogenin (VTG) levels were reduced in females while increased in males and juvenile fish considerably, as compared with the control. These results suggested that DCNP affects the HPG-axis in a sex-dependent way. Testosterone (T) levels in the plasma were significantly lower in adult and juvenile fish and were accompanied by an increased estradiol (E2)/T ratio. Histopathological observation revealed hypertrophy of the hepatocytes and nuclear pyknosis in the liver, the inhibition of spermatogenesis in the testes, and the degeneration of oocytes in the ovaries after DCNP exposure. The expression pattern of selected genes indicated that the nuclear receptor, steroidogenesis and gonadotropin regulation pathways were perturbed after DCNP exposure. Above all, our results demonstrated that DCNP clearly had anti-androgenic activity in both adult and juvenile fish and can therefore be considered as an endocrine-disrupting chemical. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of exposure to Streptococcus iniae on microRNA expression in the head kidney of genetically improved farmed tilapia (Oreochromis niloticus).

PubMed

Qiang, Jun; Tao, Fanyi; He, Jie; Sun, Lanyi; Xu, Pao; Bao, Wenjin

2017-02-20

Genetically improved farmed tilapia (GIFT, Oreochromis niloticus) are susceptible to infection by Streptococcus iniae when maintained in modern intensive culture systems. GIFT are commercially important fishes that are cultured widely in southern China. The role of microRNAs (miRNAs) in the regulatory response of GIFT to S. iniae infection has been underestimated and has not yet been well studied. Head kidney has an important immune function in teleost fishes. The main aim of this study was to determine the possible function of miRNAs in head kidney of S. iniae-infected GIFT. MiRNAs are small, non-coding RNAs that regulate gene expression by binding to the 3'-untranslated regions of their target mRNAs. MiRNAs are known to regulate immune-regulated signaling and inflammatory response pathways. High-throughput deep sequencing of two libraries (control group [CO] and infected group [IN]) of RNA extracted from GIFT head kidney tissues generated 12,089,630 (CO) and 12,624,975 (IN) clean reads. Bioinformatics analysis identified 1736 and 1729 conserved miRNAs and 164 and 165 novel miRNAs in the CO and IN libraries, respectively. Three miRNAs (miR-310-3p, miR-92, and miR-127) were found to be up-regulated and four miRNAs (miR-92d-3p, miR-375-5p, miR-146-3p, and miR-694) were found to be down-regulated in the S. iniae-infected GIFT. The expressions of these miRNAs were verified by quantitative real-time PCR. RNAhybrid and TargetScan were used to identify complementary miRNA and mRNA target sites, and the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases were used to annotate and predict potential downstream regulation of biological pathways. Seven target genes, which encode immune-related proteins (complement C3, cytidine deaminase, regulator of G-protein Rgs22, mitogen-activated protein kinase Mapk1, metabotropic glutamate receptorm GluR8, calcium-sensing receptor CaSR, and microtubule-associated protein Map1S) were predicted to play crucial roles in the GIFT response to S. iniae infection. S. iniae outbreaks have hindered the development of the tilapia industry in China. Understanding the miRNA transcriptome of S. iniae-infected GIFT is important for exploring the immune responses regulated by miRNAs as well as for studying novel regulated networks to prevent and treat S. iniae infections in the future.

50 CFR 648.91 - Monkfish regulated mesh areas and restrictions on gear and methods of fishing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... restrictions on gear and methods of fishing. 648.91 Section 648.91 Wildlife and Fisheries FISHERY CONSERVATION... § 648.91 Monkfish regulated mesh areas and restrictions on gear and methods of fishing. All vessels fishing for, possessing or landing monkfish must comply with the following minimum mesh size, gear, and...

50 CFR 648.91 - Monkfish regulated mesh areas and restrictions on gear and methods of fishing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... restrictions on gear and methods of fishing. 648.91 Section 648.91 Wildlife and Fisheries FISHERY CONSERVATION... § 648.91 Monkfish regulated mesh areas and restrictions on gear and methods of fishing. All vessels fishing for, possessing or landing monkfish must comply with the following minimum mesh size, gear, and...

Seasonal expression of arginine vasotocin mRNA and its correlations to gonadal steroidogenic enzymes and sexually dimorphic coloration during sex reversal in the gilthead seabream (Sparus aurata).

PubMed

Reyes-Tomassini, José J; Wong, Ten-Tsao; Zohar, Yonathan

2017-06-01

Arginine vasotocin is a hormone produced in the hypothalamus of teleost fish that has been shown to regulate gonad development and sexual behavior. To study the role of arginine vasotocin in the gonadal cycle of the hermaphrodite gilthead seabream, Sparus aurata, we cloned the seabream arginine vasotocin (avt) complementary DNA (cDNA). We investigated the expression of brain avt throughout the gonad cycle using real-time quantitative PCR and compared its expression levels to the expression levels of two key gonadal steroidogenic enzymes, cyp19a1a and cyp11b2. In July, when the process of sex reversal is thought to begin, avt expression was elevated over the previous 2 months. Avt in the brain remained at or above the level of July until November then peaked again in December. There was no difference between males and females in the expression levels of brain avt throughout the year. However, only in ambisexual fish was the expression of the cyp19a1a gonadal aromatase correlated to the expression of avt in the brain. Cyp11b2 did not show any correlation to brain avt expression. We also found that females had more intense body coloration than males and that this intensity peaked prior to spawning. Avt expression and female coloration were positively correlated. The fact that brain avt expression was lowest during gonad quiescence, together with the observation of a correlation between brain avt with gonadal cyp19a1a and body coloration during that time suggests that avt may play a role during the process of sex reversal and spawning of the gilthead seabream.

Impacts of Early Life Stress on the Methylome and Transcriptome of Atlantic Salmon.

PubMed

Moghadam, Hooman K; Johnsen, Hanne; Robinson, Nicholas; Andersen, Øivind; H Jørgensen, Even; Johnsen, Helge K; Bæhr, Vegar J; Tveiten, Helge

2017-07-10

Exposure to environmental stressors during early-life stages can change the rate and timing of various developmental processes. Epigenetic marks affecting transcriptional regulation can be altered by such environmental stimuli. To assess how stress might affect the methylome and transcriptome in salmon, fish were treated using cold-shock and air-exposure from the eye-stage until start-feeding. The fish were either stressed prior to hatching (E), post-hatching (PH), pre- and post-hatching (EPH) or not stressed (CO). Assessing transcriptional abundances just prior to start feeding, E and PH individuals were found to have modified the expression of thousands of genes, many with important functions in developmental processes. The EPH individuals however, showed expression similar to those of CO, suggesting an adaptive response to extended periods of stress. The methylome of stressed individuals differed from that of the CO, suggesting the importance of environment in shaping methylation signatures. Through integration of methylation with transcription, we identified bases with potential regulatory functions, some 10s of kb away from the targeted genes. We then followed fish growth for an additional year. Individuals in EPH showed superior growth compared to other treatment groups, highlighting how stress can potentially have long-lasting effects on an organism's ability to adapt to environmental perturbations.

Class B CpG-ODN2006 is highly associated with IgM and antimicrobial peptide gene expression through TLR9 pathway in yellowtail Seriola lalandi.

PubMed

Angulo, Carlos; Alamillo, Erika; Hirono, Ikuo; Kondo, Hidehiro; Jirapongpairoj, Walissara; Perez-Urbiola, Juan Carlos; Reyes-Becerril, Martha

2018-06-01

The purpose of this study was to characterize the TLR9 gene from yellowtail (Seriola lalandi) and evaluate its functional activity using the class B Cytosine-phosphate-guanine-oligodeoxynucleotide2006 (CpG-ODN2006) in an in vivo experiment after one-week immunostimulation. The gene expressions of TLR9, Immunoglobulin M (IgM), antimicrobial peptides and cytokines were evaluated by real time PCR, and humoral immune parameters were analyzed in serum. The TLR9 nucleotide sequence from yellowtail was obtained using the whole-genome shotgun sequencing method and bioinformatics tools. The yellowtail full-length cDNA sequence of SlTLR9 was 3789 bp in length, including a 66-bp 5'-untranslated region (UTR), a 3'-UTR of 528 bp, and an open reading frame (ORF) of 3192 bp translatable to 1064 amino acid showing a high degree of similarity with the counterparts of other fish species and sharing common structural architecture of the TLR family, including LRR domains, one C-terminal LRR region, and a TIR domain. Gene expression studies revealed the constitutive expression of TLR9 mRNA in all analyzed tissues; the highest levels were observed in intestine, liver and spleen where they play an important role in the fish immune system. The expression levels of TLR9 after B class CpG-ODN2006 (the main TLR9-agonist) was significantly up-regulated in all analyzed tissues, with the high expression observed in spleen followed by intestine and skin. The CpG-B has been shown as a potent B cell mitogen, and interestingly, IgM mRNA transcript was up-regulated in spleen and intestine, which was highly correlated with TLR9 after CpG-ODN2006 stimulation. The antimicrobial peptides, piscidin and NK-lysine, were up-regulated in spleen and gill after CpG-ODN2006 injection with a high correlation (r ≥ 0.82) with TLR9 gene expression. Cytokine genes were up-regulated in spleen, intestine and skin after CpG-ODN was compared with the control group. No significant correlation was observed between TLR9 and IL-1β, TNF-α and Mx gene expressions. The results showed that CpG-ODN2006 intraperitoneal injection enhanced lysozyme, peroxidase and superoxide dismutase activities in serum and demonstrated that CpG-ODN2006 can induce a specific immune response via TLR9 in which IgM and antimicrobial peptides must have an important role in the defense mechanisms against infections in yellowtail. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of acute handling stress on short-term central expression of orexigenic/anorexigenic genes in zebrafish.

PubMed

Cortés, Raul; Teles, Mariana; Oliveira, Miguel; Fierro-Castro, Camino; Tort, Lluis; Cerdá-Reverter, José Miguel

2018-02-01

Physiological mechanisms driving stress response in vertebrates are evolutionarily conserved. These mechanisms involve the activation of both the hypothalamic-sympathetic-chromaffin cell (HSC) and the hypothalamic-pituitary-adrenal (HPA) axes. In fish, the reduction of food intake levels is a common feature of the behavioral response to stress but the central mechanisms coordinating the energetic response are not well understood yet. In this work, we explore the effects of acute stress on key central systems regulating food intake in fish as well as on total body cortisol and glucose levels. We show that acute stress induced a rapid increase in total body cortisol with no changes in body glucose, at the same time promoting a prompt central response by activating neuronal pathways. All three orexigenic peptides examined, i.e., neuropeptide y (npy), agouti-related protein (agrp), and ghrelin, increased their central expression level suggesting that these neuronal systems are not involved in the short-term feeding inhibitory effects of acute stress. By contrast, the anorexigenic precursors tested, i.e., cart peptides and pomc, exhibited increased expression after acute stress, suggesting their involvement in the anorexigenic effects.

Dissecting Transcriptional Heterogeneity in Pluripotency: Single Cell Analysis of Mouse Embryonic Stem Cells.

PubMed

Guedes, Ana M V; Henrique, Domingos; Abranches, Elsa

2016-01-01

Mouse Embryonic Stem cells (mESCs) show heterogeneous and dynamic expression of important pluripotency regulatory factors. Single-cell analysis has revealed the existence of cell-to-cell variability in the expression of individual genes in mESCs. Understanding how these heterogeneities are regulated and what their functional consequences are is crucial to obtain a more comprehensive view of the pluripotent state.In this chapter we describe how to analyze transcriptional heterogeneity by monitoring gene expression of Nanog, Oct4, and Sox2, using single-molecule RNA FISH in single mESCs grown in different cell culture medium. We describe in detail all the steps involved in the protocol, from RNA detection to image acquisition and processing, as well as exploratory data analysis.

Dietary phenylalanine-improved intestinal barrier health in young grass carp (Ctenopharyngodon idella) is associated with increased immune status and regulated gene expression of cytokines, tight junction proteins, antioxidant enzymes and related signalling molecules.

PubMed

Feng, Lin; Li, Wen; Liu, Yang; Jiang, Wei-Dan; Kuang, Sheng-Yao; Jiang, Jun; Tang, Ling; Wu, Pei; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

2015-08-01

The present work evaluated the effects of dietary phenylalanine (Phe) on the intestinal immune response, tight junction proteins transcript abundance, and the gene expression of immune- and antioxidant-related signalling molecules in the intestine. In addition, the dietary Phe (and Phe + Tyr) requirement of young grass carp (Ctenopharyngodon idella) was also estimated. Fish were fed fish meal-casein-gelatin based diets (302.3 g crude protein kg(-1)) containing 3.4 (basal diet), 6.1, 9.1, 11.5, 14.0 and 16.8 g Phe kg(-1) with a fixed amount of 10.7 g tyrosine kg(-1) for 8 weeks. The results showed that Phe deficiency or excess Phe reduced the lysozyme and acid phosphatase activities and complement C 3 content in the intestine (P < 0.05). Moreover, zonula occludens-1 (ZO-1), occludin and claudin c mRNA levels were highest in the fish fed the diet containing 11.5 g Phe kg(-1) (P < 0.05). However, claudin 12 and claudin b mRNA levels were not significantly affected by dietary Phe (P > 0.05). Gene expression of interleukin-10 (IL-10), transforming growth factor-β1 (TGF-β1), target of rapamycin (TOR) and inhibitor of nuclear factor κBα (IκBα) in proximal intestine (PI), mid intestine (MI) and distal intestine (DI) increased as dietary Phe increased up to 6.1, 9.1, 11.5 and 14.0 g kg(-1), respectively (P < 0.05). However, interleukin-8 (IL-8), tumour necrosis factor-α (TNF-α) and nuclear factor-κB p65 (NF-κB p65) mRNA levels showed opposite tendencies. In addition, the mRNA level of superoxide dismutase (SOD) was significantly lower in the intestinal tissue of the group fed a diet with Phe levels of 16.8 g kg(-1) than in those of other groups (P < 0.05). The expression of NF-E2-related factor 2 (Nrf2) gene was increased as dietary Phe increased up to 9.1 g kg(-1) (P < 0.05). In conclusion, Phe improved intestinal immune status, and regulated gene expression of cytokines, tight junction proteins, antioxidant enzymes, NF-κB p65, IκBα, TOR, and Nrf2 in the fish intestine. Based on the quadratic regression analysis of lysozyme activity at a 95% maximum, the dietary Phe requirement of young grass carp (256-629 g) was estimated to be 8.31 g kg(-1), corresponding to 2.75 g 100 g(-1) protein. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gene cloning and expression analysis of IRF1 in half-smooth tongue sole (Cynoglossus semilaevis).

PubMed

Lu, Yang; Wang, Qilong; Liu, Yang; Shao, Changwei; Chen, Songlin; Sha, Zhenxia

2014-06-01

Interferon regulatory factor 1 (IRF1) was known to play key roles in antiviral defense in several species, and some other important biological processes. In this report, full length cDNA of IRF1 from Cynoglossus semilaevis (CsIRF1) was identified. It was of 1,455 bp, containing a 5' UTR of 104 bp, a 3' UTR of 541 bp with a poly (A) tail and an ORF of 810 bp encoding a putative protein of 269 amino acids. The putative CsIRF1protein contained one conserved IRF domain (1-113aa), and two low complexity regions (140-158aa and 230-242aa, respectively). Phylogenetic analysis showed that CsIRF1 was conserved in the teleost evolutionary branch, which was independent of mammalian, birds and amphibians. Additionally, CsIRF1 had the 96% homology with marine fishes, while 66% with freshwater fishes. The expression profiles of CsIRF1was analyzed by quantitative real-time PCR in healthy tissues and in immune tissues challenged with different pathogens [Vibrio anguillarum and Lymphocystis disease virus (LCDV)], respectively. CsIRF1 was widely expressed in healthy tissues of Cynoglossus semilaevis and with the highest expression in blood, as much as 19 times of that in liver. V. anguillarum and LCDV both induced the CsIRF1 gene expression distinctly in liver, with the peak value reached to 98-fold at 6 h and 25-fold at 24 h, respectively. The bacteria induced CsIRF1 suddenly up-expression in each detected tissues. However, at the initial stage of the challenge of virus LCDV, the CsIRF1 expression in blood and spleen were up regulated; on the contrary, its expression in liver and head kidney were down regulated, 0.3 and 0.4-fold 6 h post virus injection, respectively. These results suggested that CsIRF1 gene might involve in not only antiviral activity but also antibacterial procedure, indicating its vital role in Cynoglossus semilaevis innate defense system.

Unravelling the neurophysiological basis of aggression in a fish model

PubMed Central

2010-01-01

Background Aggression is a near-universal behaviour with substantial influence on and implications for human and animal social systems. The neurophysiological basis of aggression is, however, poorly understood in all species and approaches adopted to study this complex behaviour have often been oversimplified. We applied targeted expression profiling on 40 genes, spanning eight neurological pathways and in four distinct regions of the brain, in combination with behavioural observations and pharmacological manipulations, to screen for regulatory pathways of aggression in the zebrafish (Danio rerio), an animal model in which social rank and aggressiveness tightly correlate. Results Substantial differences occurred in gene expression profiles between dominant and subordinate males associated with phenotypic differences in aggressiveness and, for the chosen gene set, they occurred mainly in the hypothalamus and telencephalon. The patterns of differentially-expressed genes implied multifactorial control of aggression in zebrafish, including the hypothalamo-neurohypophysial-system, serotonin, somatostatin, dopamine, hypothalamo-pituitary-interrenal, hypothalamo-pituitary-gonadal and histamine pathways, and the latter is a novel finding outside mammals. Pharmacological manipulations of various nodes within the hypothalamo-neurohypophysial-system and serotonin pathways supported their functional involvement. We also observed differences in expression profiles in the brains of dominant versus subordinate females that suggested sex-conserved control of aggression. For example, in the HNS pathway, the gene encoding arginine vasotocin (AVT), previously believed specific to male behaviours, was amongst those genes most associated with aggression, and AVT inhibited dominant female aggression, as in males. However, sex-specific differences in the expression profiles also occurred, including differences in aggression-associated tryptophan hydroxylases and estrogen receptors. Conclusions Thus, through an integrated approach, combining gene expression profiling, behavioural analyses, and pharmacological manipulations, we identified candidate genes and pathways that appear to play significant roles in regulating aggression in fish. Many of these are novel for non-mammalian systems. We further present a validated system for advancing our understanding of the mechanistic underpinnings of complex behaviours using a fish model. PMID:20846403

ISA virus regulates the generation of reactive oxygen species and p47phox expression in a p38 MAPK-dependent manner in Salmo salar.

PubMed

Olavarría, Víctor H; Valdivia, Sharin; Salas, Boris; Villalba, Melina; Sandoval, Rodrigo; Oliva, Harold; Valdebenito, Samuel; Yañez, Alejandro

2015-02-01

Several viruses, including Orthomyxovirus, utilize cellular reactive oxygen species (ROS) for viral genomic replication and survival within host cells. However, the role of ROS in early events of viral entry and signal induction has not been elucidated. Here, we show that ISA virus (ISAV) induces ROS production very early during infection of CHSE-214 and SHK-1Ycells, and that production is sustained over the observed 24h post-infection. The mitogen-activated protein kinase (MAPK) family is responsible for important signaling pathways. In this study, we report that ISAV activates ERK and p38 in Salmo salar. In salmonid macrophages, while ERK was required for SOD, GLURED, p47phox expression, p38 regulated the ROS production by the NADPH oxidase complex activation. These results, together with the presence of several consensus target motifs for p38 MAPK in the promoter of the S. salar p47phox gene, suggest that p38 MAPK regulates p47phox gene expression in fish through the activation of this key transcription factor. Copyright © 2014 Elsevier Ltd. All rights reserved.

A survey of dioxin-like contaminants in fish from recreational fishing.

PubMed

Heimstad, Eldbjørg Sofie; Grønstøl, Gaute; Hetland, Karl Torstein; Alarcon, Javier Martinez; Rylander, Charlotta; Mariussen, Espen

2015-08-01

The dioxin and dioxin-like compounds are regarded as one of the most toxic group of environmental contaminants. Food for the commercial market is regularly monitored for their dioxin levels and the concentration allowed in food is strictly regulated. Less is known about locally caught fish from recreational fishing, which is often brought home for consumption. This can be fish caught from nearby lakes or streams or fish with marine origin close to industrial areas or harbours that are not regularly monitored for their dioxin levels. In this study, we established collaboration with schools in 13 countries. We received 203 samples of 29 different fish species of which Atlantic cod was the most abundant followed by brown trout and pollock. In general, the majority of samples from the participating countries had low concentrations (between 0.1 and 0.2 pg/g chemical-activated luciferase gene expression toxic equivalency wet weight (CALUX TEQ w.w.)) of dioxins and dioxin-like PCBs. Only 18 samples had concentrations above 1 pg/g CALUX TEQ w.w., and only 2 dab samples had concentration above maximum levels set by the European Commission. The Atlantic cod samples showed a significant reduction in the concentrations of dioxins with increasing latitude indicating less contamination of dioxin and dioxin-like compounds in the north of Norway. The results indicate that a moderate consumption of self-caught fish at presumed non-contaminated sites does not represent a major risk for exposure to dioxins or dioxin-like compounds at concentrations associated with adverse health effects. Recreational fishermen should, however, obtain knowledge about local fish consumption advice.

Resveratrol post-transcriptionally regulates pro-inflammatory gene expression via regulation of KSRP RNA binding activity

PubMed Central

Bollmann, Franziska; Art, Julia; Henke, Jenny; Schrick, Katharina; Besche, Verena; Bros, Matthias; Li, Huige; Siuda, Daniel; Handler, Norbert; Bauer, Florian; Erker, Thomas; Behnke, Felix; Mönch, Bettina; Härdle, Lorena; Hoffmann, Markus; Chen, Ching-Yi; Förstermann, Ulrich; Dirsch, Verena M.; Werz, Oliver; Kleinert, Hartmut; Pautz, Andrea

2014-01-01

Resveratrol shows beneficial effects in inflammation-based diseases like cancer, cardiovascular and chronic inflammatory diseases. Therefore, the molecular mechanisms of the anti-inflammatory resveratrol effects deserve more attention. In human epithelial DLD-1 and monocytic Mono Mac 6 cells resveratrol decreased the expression of iNOS, IL-8 and TNF-α by reducing mRNA stability without inhibition of the promoter activity. Shown by pharmacological and siRNA-mediated inhibition, the observed effects are SIRT1-independent. Target-fishing and drug responsive target stability experiments showed selective binding of resveratrol to the RNA-binding protein KSRP, a central post-transcriptional regulator of pro-inflammatory gene expression. Knockdown of KSRP expression prevented resveratrol-induced mRNA destabilization in human and murine cells. Resveratrol did not change KSRP expression, but immunoprecipitation experiments indicated that resveratrol reduces the p38 MAPK-related inhibitory KSRP threonine phosphorylation, without blocking p38 MAPK activation or activity. Mutation of the p38 MAPK target site in KSRP blocked the resveratrol effect on pro-inflammatory gene expression. In addition, resveratrol incubation enhanced KSRP-exosome interaction, which is important for mRNA degradation. Finally, resveratrol incubation enhanced its intra-cellular binding to the IL-8, iNOS and TNF-α mRNA. Therefore, modulation of KSRP mRNA binding activity and, thereby, enhancement of mRNA degradation seems to be the common denominator of many anti-inflammatory effects of resveratrol. PMID:25352548

Genomic analysis of the host response to nervous necrosis virus in Atlantic cod (Gadus morhua) brain.

PubMed

Krasnov, Aleksei; Kileng, Øyvind; Skugor, Stanko; Jørgensen, Sven Martin; Afanasyev, Sergey; Timmerhaus, Gerrit; Sommer, Ann-Inger; Jensen, Ingvill

2013-07-01

Genome sequencing combined with transcriptome profiling promotes exploration of defence against pathogens and discovery of immune genes. Based on sequences from the recently released genome of Atlantic cod, a genome-wide oligonucleotide microarray (ACIQ-1) was designed and used for analyses of gene expression in the brain during infection with nervous necrosis virus (NNV). A challenge experiment with NNV was performed with Atlantic cod juveniles and brain samples from virus infected and uninfected fish were used for microarray analysis. Expression of virus induced genes increased at 5 days post challenge and persisted at stable level to the last sampling at 25 days post challenge. A large fraction of the up-regulated genes (546 features) were known or expected to have immune functions and most of these have not previously been characterized in Atlantic cod. Transcriptomic changes induced by the virus involved strong activation of genes associated with interferon and tumour necrosis factor related responses and acute inflammation. Up-regulation of genes involved in adaptive immunity suggested a rapid recruitment of B and T lymphocytes to the NNV infected brain. QPCR analyses of 15 candidate genes of innate immunity showed rapid induction by poly(I:C) in Atlantic cod larvae cells suggesting an antiviral role. Earliest and greatest expression changes after poly I:C stimulation was observed for interferon regulatory factors IRF4 and IRF7. Comparative studies between teleost species provided new knowledge about the evolution of innate antiviral immunity in fish. A number of genes is present or responds to viruses only in fish. Innate immunity of Atlantic cod is characterized by selective expansion of several medium-sized multigene families with ribose binding domains. An interesting finding was the high representation of three large gene families among the early antiviral genes, including tripartite motif proteins (TRIM) and proteins with PRY-SPRY and NACHT domains. The latter two with respectively 52 and 114 members in Atlantic cod have gone through expansions in different groups of fish. These proteins most likely have ligand binding properties and their propagation could be linked to the loss of MHC class II in the Atlantic cod genome. Copyright © 2013 Elsevier Ltd. All rights reserved.

Leptin receptor-deficient (knockout) medaka, Oryzias latipes, show chronical up-regulated levels of orexigenic neuropeptides, elevated food intake and stage specific effects on growth and fat allocation.

PubMed

Chisada, Shin-ichi; Kurokawa, Tadahide; Murashita, Koji; Rønnestad, Ivar; Taniguchi, Yoshihito; Toyoda, Atsushi; Sakaki, Yoshiyuki; Takeda, Shunichi; Yoshiura, Yasutoshi

2014-01-01

The first studies that identified leptin and its receptor (LepR) in mammals were based on mutant animals that displayed dramatic changes in body-weight and regulation of energy homeostasis. Subsequent studies have shown that a deficiency of leptin or LepR in homoeothermic mammals results in hyperphagia, obesity, infertility and a number of other abnormalities. The physiological roles of leptin-mediated signaling in ectothermic teleosts are still being explored. Here, we produced medaka with homozygous LepR gene mutation using the targeting induced local lesions in a genome method. This knockout mutant had a point mutation of cysteine for stop codon at the 357th amino acid just before the leptin-binding domain. The evidence for loss of function of leptin-mediated signaling in the mutant is based on a lack of response to feeding in the expression of key appetite-related neuropeptides in the diencephalon. The mutant lepr−/− medaka expressed constant up-regulated levels of mRNA for the orexigenic neuropeptide Ya and agouti-related protein and a suppressed level of anorexigenic proopiomelanocortin 1 in the diencephalon independent of feeding, which suggests that the mutant did not possess functional LepR. Phenotypes of the LepR-mutant medaka were analyzed in order to understand the effects on food intake, growth, and fat accumulation in the tissues. The food intake of the mutant medaka was higher in post-juveniles and adult stages than that of wild-type (WT) fish. The hyperphagia led to a high growth rate at the post-juvenile stage, but did not to significant alterations in final adult body size. There was no additional deposition of fat in the liver and muscle in the post-juvenile and adult mutants, or in the blood plasma in the adult mutant. However, adult LepR mutants possessed large deposits of visceral fat, unlike in the WT fish, in which there were none. Our analysis confirms that LepR in medaka exert a powerful influence on the control on food intake. Further analyses using the mutant will contribute to a better understanding of the role of leptin in fish. This is the first study to produce fish with leptin receptor deficiency.

25 CFR 241.4 - Subsistence and sport fishing, Annette Islands Reserve.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of Fish and Game for Commercial Fishing in Fishing District No. 1. Sport fishing within the Annette... regulation for Southeastern Alaska by the Alaska Board of Fish and Game. Both subsistence and sport fishing...

Using generalized linear models to estimate selectivity from short-term recoveries of tagged red drum Sciaenops ocellatus: Effects of gear, fate, and regulation period

USGS Publications Warehouse

Bacheler, N.M.; Hightower, J.E.; Burdick, S.M.; Paramore, L.M.; Buckel, J.A.; Pollock, K.H.

2010-01-01

Estimating the selectivity patterns of various fishing gears is a critical component of fisheries stock assessment due to the difficulty in obtaining representative samples from most gears. We used short-term recoveries (n = 3587) of tagged red drum Sciaenops ocellatus to directly estimate age- and length-based selectivity patterns using generalized linear models. The most parsimonious models were selected using AIC, and standard deviations were estimated using simulations. Selectivity of red drum was dependent upon the regulation period in which the fish was caught, the gear used to catch the fish (i.e., hook-and-line, gill nets, pound nets), and the fate of the fish upon recovery (i.e., harvested or released); models including all first-order interactions between main effects outperformed models without interactions. Selectivity of harvested fish was generally dome-shaped and shifted toward larger, older fish in response to regulation changes. Selectivity of caught-and-released red drum was highest on the youngest and smallest fish in the early and middle regulation periods, but increased on larger, legal-sized fish in the late regulation period. These results suggest that catch-and-release mortality has consistently been high for small, young red drum, but has recently become more common in larger, older fish. This method of estimating selectivity from short-term tag recoveries is valuable because it is simpler than full tag-return models, and may be more robust because yearly fishing and natural mortality rates do not need to be modeled and estimated. ?? 2009 Elsevier B.V.

Using generalized linear models to estimate selectivity from short-term recoveries of tagged red drum Sciaenops ocellatus: Effects of gear, fate, and regulation period

USGS Publications Warehouse

Burdick, Summer M.; Hightower, Joseph E.; Bacheler, Nathan M.; Paramore, Lee M.; Buckel, Jeffrey A.; Pollock, Kenneth H.

2010-01-01

Estimating the selectivity patterns of various fishing gears is a critical component of fisheries stock assessment due to the difficulty in obtaining representative samples from most gears. We used short-term recoveries (n = 3587) of tagged red drum Sciaenops ocellatus to directly estimate age- and length-based selectivity patterns using generalized linear models. The most parsimonious models were selected using AIC, and standard deviations were estimated using simulations. Selectivity of red drum was dependent upon the regulation period in which the fish was caught, the gear used to catch the fish (i.e., hook-and-line, gill nets, pound nets), and the fate of the fish upon recovery (i.e., harvested or released); models including all first-order interactions between main effects outperformed models without interactions. Selectivity of harvested fish was generally dome-shaped and shifted toward larger, older fish in response to regulation changes. Selectivity of caught-and-released red drum was highest on the youngest and smallest fish in the early and middle regulation periods, but increased on larger, legal-sized fish in the late regulation period. These results suggest that catch-and-release mortality has consistently been high for small, young red drum, but has recently become more common in larger, older fish. This method of estimating selectivity from short-term tag recoveries is valuable because it is simpler than full tag-return models, and may be more robust because yearly fishing and natural mortality rates do not need to be modeled and estimated.

Constraints upon the Response of Fish and Crayfish to Environmental Flow Releases in a Regulated Headwater Stream Network

PubMed Central

Chester, Edwin T.; Matthews, Ty G.; Howson, Travis J.; Johnston, Kerrylyn; Mackie, Jonathon K.; Strachan, Scott R.; Robson, Belinda J.

2014-01-01

In dry climate zones, headwater streams are often regulated for water extraction causing intermittency in perennial streams and prolonged drying in intermittent streams. Regulation thereby reduces aquatic habitat downstream of weirs that also form barriers to migration by stream fauna. Environmental flow releases may restore streamflow in rivers, but are rarely applied to headwaters. We sampled fish and crayfish in four regulated headwater streams before and after the release of summer-autumn environmental flows, and in four nearby unregulated streams, to determine whether their abundances increased in response to flow releases. Historical data of fish and crayfish occurrence spanning a 30 year period was compared with contemporary data (electrofishing surveys, Victoria Range, Australia; summer 2008 to summer 2010) to assess the longer–term effects of regulation and drought. Although fish were recorded in regulated streams before 1996, they were not recorded in the present study upstream or downstream of weirs despite recent flow releases. Crayfish (Geocharax sp. nov. 1) remained in the regulated streams throughout the study, but did not become more abundant in response to flow releases. In contrast, native fish (Gadopsis marmoratus, Galaxias oliros, Galaxias maculatus) and crayfish remained present in unregulated streams, despite prolonged drought conditions during 2006–2010, and the assemblages of each of these streams remained essentially unchanged over the 30 year period. Flow release volumes may have been too small or have operated for an insufficient time to allow fish to recolonise regulated streams. Barriers to dispersal may also be preventing recolonisation. Indefinite continuation of annual flow releases, that prevent the unnatural cessation of flow caused by weirs, may eventually facilitate upstream movement of fish and crayfish in regulated channels; but other human–made dispersal barriers downstream need to be identified and ameliorated, to allow native fish to fulfil their life cycles in these headwater streams. PMID:24647407

Structural and functional characterizations of activin type 2B receptor (acvr2b) ortholog from the marine fish, gilthead sea bream, Sparus aurata: evidence for gene duplication of acvr2b in fish.

PubMed

Funkenstein, Bruria; Krol, Ekaterina; Esterin, Elena; Kim, Yong-Soo

2012-12-01

Myostatin (MSTN), a negative regulator of muscle growth and a member of the transforming growth factor-β superfamily, can bind the two activin type 2 receptors (ACVR2). It has been previously shown that WT mice injected with ACVR2B extracellular domain (ACVR2B-ECD) had higher muscle mass. Likewise, fish larvae immersed in Pichia pastoris culture supernatant, containing goldfish Acvr2b-ECD, showed enhanced larval growth. However, it is not clear whether fish Mstn1 and Mstn2 signal through the same receptor and whether fish express more than one acvr2b gene. In the current study, three cDNAs encoding acvr2b (saacvr2b-1, saacvr2b-2a, and saacvr2b-2b) were cloned from gilthead sea bream. All three contain the short extracellular binding domain, a short transmembrane region, and a conserved catalytic domain of serine/threonine protein kinase. Bioinformatics analysis provided evidence for the existence of two acvr2b genes (acvr2b-1 and acvr2b-2) in several other fish species as well, probably as a result of gene or genome duplication. The two isoforms differ in their amino acid sequences. The direct inhibitory effect of Acvr2b-ECD on Mstn activity was tested in vitro. The saAcvr2b-1-ECD was expressed in the yeast P. pastoris. Evidence is provided for N-glycosylation of Acvr2b-1-ECD. The affinity-purified Acvr2b-1-ECD inhibited recombinant mouse/rat/human mature MSTN activity when determined in vitro using the CAGA-luciferase assay in A204 cells. A lower inhibitory activity was obtained when unprocessed purified, furin-digested, and activated saMstn1 was used. Results of this study demonstrate for the first time the existence of two acvr2b genes in fish. In addition, the study shows that bioactive fish Acvr2b-ECD can be produced from P. pastoris.

76 FR 3937 - 2010-2011 Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-21

...The Fish and Wildlife Service adds one refuge to the list of areas open for hunting and/or sport fishing and increases the activities available at seven other refuges, along with pertinent refuge-specific regulations on other refuges that pertain to migratory game bird hunting, upland game hunting, big game hunting, and sport fishing for the 2010-2011 season.

Solute carriers (SLCs) identified and characterized from kidney transcriptome of golden mahseer (Tor putitora) (Fam: Cyprinidae).

PubMed

Barat, Ashoktaru; Sahoo, Prabhati Kumari; Kumar, Rohit; Pande, Veena

2016-10-01

The solute carriers (SLC) are trans-membrane proteins, those regulate the transport of various substances (sugars, amino acids, nucleotides, inorganic cations/anions, metals, drugs etc.) across the cell membrane. There are more than 338 solute carriers (slc) reported in fishes that play crucial role in cellular influx and efflux. The study of solute carrier families may reveal many answers regarding the function of transporter genes in the species and their effect in the existing environment. Therefore, we performed RNA sequencing of kidney tissue of the golden mahseer (Tor putitora) using Illumina platform to identify the solute carrier families and characterized 24 putative functional genes under 15 solute carrier families. Out of 24 putative functional genes, 11 genes were differentially expressed in different tissues (head kidney, trunk kidney, spleen, liver, gill, muscle, intestine and brain) using qRT-PCR assay. The slc5a1, slc5a12, slc12a3, slc13a3, slc22a13 and slc26a6 were highly expressed in kidney. The slc15a2, slc25a47, slc33a1 and slc38a2 were highly expressed in brain and slc30a5 was over-expressed in gill. The unrooted phylogenetic trees of slc2, slc5, slc13 and slc33 were constructed using amino acid sequences of Homo sapiens, Salmo salar, Danio rerio, Cyprinus carpio and Tor putitora. It appears that all the putative solute carrier families are very much conserved in human and fish species including the present fish, golden mahseer. This study provides the first hand database of solute carrier families particularly transporter encoding proteins in the species. Copyright © 2016 Elsevier Inc. All rights reserved.

Threonine modulates immune response, antioxidant status and gene expressions of antioxidant enzymes and antioxidant-immune-cytokine-related signaling molecules in juvenile blunt snout bream (Megalobrama amblycephala).

PubMed

Habte-Tsion, Habte-Michael; Ren, Mingchun; Liu, Bo; Ge, Xianping; Xie, Jun; Chen, Ruli

2016-04-01

A 9-week feeding trial was conducted to investigate the effects of graded dietary threonine (Thr) levels (0.58-2.58%) on the hematological parameters, immune response, antioxidant status and hepatopancreatic gene expression of antioxidant enzymes and antioxidant-immune-cytokine-related signaling molecules in juvenile blunt snout bream. For this purpose, 3 tanks were randomly arranged and assigned to each experimental diet. Fish were fed with their respective diet to apparent satiation 4 times daily. The results indicated that white blood cell, red blood cell and haemoglobin significantly responded to graded dietary Thr levels, while hematocrit didn't. Complement components (C3 and C4), total iron-binding capacity (TIBC), immunoglobulin M (IgM), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) increased with increasing dietary Thr levels up to 1.58-2.08% and thereafter tended to decrease. Dietary Thr regulated the gene expressions of Cu/Zn-SOD, Mn-SOD and CAT, GPx1, glutathione S-transferase mu (GST), nuclear factor erythroid 2-related factor 2 (Nrf2), heat shock protein-70 (Hsp70), tumor necrosis factor-alpha (TNF-α), apolipoprotein A-I (ApoA1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and fructose-bisphosphate aldolase B (ALDOB); while the gene expression of peroxiredoxin II (PrxII) was not significantly modified by graded Thr levels. These genes are involved in different functions including antioxidant, immune, and defense responses, energy metabolism and protein synthesis. Therefore, this study could provide a new molecular tool for studies in fish immunonutrition and shed light on the regulatory mechanisms that dietary Thr improved the antioxidant and immune capacities of fish. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cloning of cytochrome P450 3A137 complementary DNA in silver carp and expression induction by ionic liquid.

PubMed

Li, Xiaoyu; Ma, Junguo; Lei, Wenlong; Li, Jie; Zhang, Yaning; Li, Yuanlong

2013-08-01

Cytochrome P450 (CYP) enzymes, especially CYP 3A, are responsible for metabolizing of various kinds of endogenous and exogenous compounds in animals. In the present study, a full-length sequence of CYP 3A137 cDNA in silver carp was cloned and sequenced, and then a phylogenetic tree of CYP 3A was structured. Additionally, the acute toxicity of the ionic liquid 1-octyl-3-methylimidazolium bromide ([C8mim]Br) on silver carp and transcription and microsome enzyme activity of CYP 3A137 in the liver of silver fish after rifampicin or [C8mim]Br exposure were also determined in this study. The results show that the full length of CYP 3A137 cDNA is 1810 base pair (bp) long and contains an open reading frame of 1539bp encoding a protein of 513 amino acids. Sequence analysis reveals that CYP 3A137 is highly conserved in fish. Moreover, the results of quantitative real-time polymerase chain reaction reveal that CYP 3A137 in silver carp is constitutively expressed in all tissues examined and the sequence of expression rate is liver>intestine>kidney>spleen>brain>heart>muscle. Finally, the results of acute toxicity tests indicate that both rifampicin and [C8mim]Br significantly up-regulate the expression of CYP 3A137 at mRNA level and increase CYP 3A137 enzyme activity in fish liver, suggesting that CYP 3A137 be involved in metabolism of [C8mim]Br in silver carp. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of ration size on fillet fatty acid composition, phospholipid allostasis and mRNA expression patterns of lipid regulatory genes in gilthead sea bream (Sparus aurata).

PubMed

Benedito-Palos, Laura; Calduch-Giner, Josep A; Ballester-Lozano, Gabriel F; Pérez-Sánchez, Jaume

2013-04-14

The effect of ration size on muscle fatty acid (FA) composition and mRNA expression levels of key regulatory enzymes of lipid and lipoprotein metabolism have been addressed in juveniles of gilthead sea bream fed a practical diet over the course of an 11-week trial. The experimental setup included three feeding levels: (i) full ration until visual satiety, (ii) 70 % of satiation and (iii) 70 % of satiation with the last 2 weeks at the maintenance ration. Feed restriction reduced lipid content of whole body by 30 % and that of fillet by 50 %. In this scenario, the FA composition of fillet TAG was not altered by ration size, whereas that of phospholipids was largely modified with a higher retention of arachidonic acid and DHA. The mRNA transcript levels of lysophosphatidylcholine acyltransferases, phosphatidylethanolamine N-methyltransferase and FA desaturase 2 were not regulated by ration size in the present experimental model. In contrast, mRNA levels of stearoyl-CoA desaturases were markedly down-regulated by feed restriction. An opposite trend was found for a muscle-specific lipoprotein lipase, which is exclusive of fish lineage. Several upstream regulatory transcriptions were also assessed, although nutritionally mediated changes in mRNA transcripts were almost reduced to PPARα and β, which might act in a counter-regulatory way on lipolysis and lipogenic pathways. This gene expression pattern contributes to the construction of a panel of biomarkers to direct marine fish production towards muscle lean phenotypes with increased retentions of long-chain PUFA.

Myostatin inhibits myosatellite cell proliferation and consequently activates differentiation: evidence for endocrine-regulated transcript processing.

PubMed

Garikipati, Dilip K; Rodgers, Buel D

2012-10-01

Myostatin is a potent negative regulator of muscle growth in mammals. Despite high structural conservation, functional conservation in nonmammalian species is only assumed. This is particularly true for fish due to the presence of several myostatin paralogs: two in most species and four in salmonids (MSTN-1a, -1b, -2a, and -2b). Rainbow trout are a rich source of primary myosatellite cells as hyperplastic muscle growth occurs even in adult fish. These cells were therefore used to determine myostatin's effects on proliferation whereas our earlier studies reported its effects on quiescent cells. As in mammals, recombinant myostatin suppressed proliferation with no changes in cell morphology. Expression of MSTN-1a was several fold higher than the other paralogs and was autoregulated by myostatin, which also upregulated the expression of key differentiation markers: Myf5, MyoD1, myogenin, and myosin light chain. Thus, myostatin-stimulated cellular growth inhibition activates rather than represses differentiation. IGF-1 stimulated proliferation but had minimal and delayed effects on differentiation and its actions were suppressed by myostatin. However, IGF-1 upregulated MSTN-2a expression and the processing of its transcript, which is normally unprocessed. Myostatin therefore appears to partly mediate IGF-stimulated myosatellite differentiation in rainbow trout. This also occurs in mammals, although the IGF-stimulated processing of MSTN-2a transcripts is highly unique and is indicative of subfunctionalization within the gene family. These studies also suggest that the myokine's actions, including its antagonistic relationship with IGF-1, are conserved and that the salmonid gene family is functionally diverging.

Plasticity of the reproductive axis caused by social status change in an african cichlid fish: II. testicular gene expression and spermatogenesis.

PubMed

Maruska, Karen P; Fernald, Russell D

2011-01-01

Reproduction in all vertebrates is controlled by the brain-pituitary-gonad (BPG) axis, which is regulated socially in males of the African cichlid fish Astatotilapia burtoni. Although social information influences GnRH1 neurons at the apex of the BPG axis, little is known about how the social environment and dominance affects the cellular and molecular composition of the testes to regulate reproductive capacity. We created an opportunity for reproductively suppressed males to ascend in status and then measured changes in gene expression and tissue morphology to discover how quickly the perception of this opportunity can influence the testes. Our results show rapid up-regulation of mRNA levels of FSH receptor and several steroid receptor subtypes in the testes during social ascent. In contrast, LH receptor was not elevated until 72 h after ascent, but this increase was coincident with elevated circulating androgens and early stages of spermatogenesis, suggesting a role in steroidogenesis. The spermatogenic potential of the testes, as measured by cellular composition, was also elevated before the overall increase in testes size. The presence of cysts at all stages of spermatogenesis, coupled with lower levels of gonadotropin and steroid receptors in subordinate males, suggests that the BPG axis and spermatogenesis are maintained at a subthreshold level in anticipation of the chance to gain a territory and become reproductively active. Our results show that the testis is stimulated extremely quickly after perception of social opportunity, presumably to allow suppressed males to rapidly achieve high reproductive success in a dynamic social environment.

Molecular cloning and expression analysis of the retinoid X receptor (RXR) gene in golden pompano Trachinotus ovatus fed Artemia nauplii with different enrichments.

PubMed

Yang, Qibin; Zheng, Panlong; Ma, Zhenhua; Li, Tao; Jiang, Shigui; Qin, Jian G

2015-12-01

The retinoid X receptors (RXRs) are involved in the skeletal development and other biological process such as blood vessel formation and metabolism. Partial sequences of RXRα and β genes were obtained, and their expressions were quantified on golden pompano Trachinotus ovatus at 28 days post hatching (DPH) to explore the molecular response to nutritional manipulation in fish larvae. As live food, Artemia nauplii were separately enriched with Nannochloropsis and Algamac 3080 and non-enriched Artemia nauplii (control) for fish feeding. The expressions of RXRs were detected in the embryos and fish larvae at early stages, suggesting that the skeletal development in golden pompano initiated before yolk re-sorption completion. Fish fed non-enriched Artemia nauplii ended up with higher jaw malformation. The highest specific growth rate was obtained when fish were fed with the Artemia nauplii enriched with Algamac 3080, and the lowest growth rate was observed when fish were fed with unenriched Artemia nauplii. The highest survival was obtained when fish were fed with non-enriched or Nannochloropsis-enriched Artemia nauplii. This study indicates that the use of enriched formula for Artemia nauplii can significantly affect the expression levels of RXRs and jaw malformation of golden pompano larvae, but there is no clear correlation between RXRs expressions and malformation rates when fish are subjected to nutrient challenge.

Effects of Sex Steroids on Fish Leukocytes

PubMed Central

Cabas, Isabel

2018-01-01

In vertebrates, in addition to their classically reproductive functions, steroids regulate the immune system. This action is possible mainly due to the presence of steroid receptors in the different immune cell types. Much evidence suggests that the immune system of fish is vulnerable to xenosteroids, which are ubiquitous in the aquatic environment. In vivo and in vitro assays have amply demonstrated that oestrogens interfere with both the innate and the adaptive immune system of fish by regulating the main leukocyte activities and transcriptional genes. They activate nuclear oestrogen receptors and/or G-protein coupled oestrogen receptor. Less understood is the role of androgens in the immune system, mainly due to the complexity of the transcriptional regulation of androgen receptors in fish. The aim of this manuscript is to review our present knowledge concerning the effect of sex steroid hormones and the presence of their receptors on fish leukocytes, taking into consideration that the studies performed vary as regard the fish species, doses, exposure protocols and hormones used. Moreover, we also include evidence of the probable role of progestins in the regulation of the immune system of fish. PMID:29315244

Feedback from Arctic charr: Feed flavour stimulation and re-feeding after feed deprivation stimulate genes encoding both orexigenic and anorexigenic neuropeptides.

PubMed

Striberny, Anja; Jørgensen, Even H

2017-05-15

Despite vast research attention, the knowledge about central mechanisms of appetite regulation in teleost remains inconclusive. A common strategy in studies on appetite regulating mechanisms is to measure the response to feed restriction or - deprivation, but responses vary between fish species and between experiments, and are also likely dependent on the degree of energy perturbation. The anadromous Arctic charr is an interesting model for studying appetite regulation as its feeding cycle comprises months of winter anorexia, and hyperphagia during summer. Here we studied how the gene expression of putative hypothalamic appetite regulators were affected by two days, one week and one month feed deprivation during summer, and subsequent re-feeding and exposure to feed flavour. Short-term feed deprivation caused only a minor reduction in condition factor and had no effect on hypothalamic gene expression. Long-term feed-deprivation caused a marked reduction in weight and condition factor which contrasted the increase in weight and condition factor seen in ad libitum fed controls. A marked energy perturbation by feed deprivation was also indicated by a lower hypothalamic expression of the genes encoding insulin-like growth factor 1 (IGF1) and IGF1 binding protein 5 in the feed deprived charr compared to fed controls. Surprisingly, long-term feed deprivation and energy perturbation did not induce changes in hypothalamic appetite regulators. Unexpectedly, re-feeding and exposure to feed flavour caused an increase in the expression of the genes encoding the orexigenic agouti-related peptide and the anorexigenic melanocortin receptor 4 and cocaine- and amphetamine-regulated transcript. Our study gives strong evidence for a role of these in appetite regulation in Arctic charr, but their mechanisms of action remain unknown. We suggest that changes in gene expression are more likely to be registered during transition phases, e.g. from fasting to feeding and upon stimulatory inputs such as feed flavour. Copyright © 2017 Elsevier Inc. All rights reserved.

Dimorphic expression of sex-related genes in different gonadal development stages of sterlet, Acipenser ruthenus, a primitive fish species.

PubMed

Wang, Wei; Zhu, Hua; Dong, Ying; Tian, ZhaoHui; Dong, Tian; Hu, HongXia; Niu, CuiJuan

2017-12-01

Molecular mechanism of sex determination and differentiation of sturgeon, a primitive fish species, is extraordinarily important due to the valuable caviar; however, it is still poorly known. The present work aimed to identify the major genes involved in regulating gonadal development of sterlet, a small species of sturgeon, from 13 candidate genes which have been shown to relate to gonadal differentiation and development in other teleost fish. The sex and gonadal development of sterlets were determined by histological observation and levels of sex steroids testosterone (T), 11-ketotestosterone (11-KT), and 17β-estradiol (E2) in serum. Sexually dimorphic gene expressions were investigated. The results revealed that gonadal development were asynchronous in 2-year-old male and female sterlets with the testes in early or mid-spermatogenesis and the ovaries in chromatin nucleolus stage or perinucleolus stage, respectively. The levels of T and E2 were not significantly different between sexes or different gonadal development stages while 11-KT had the higher level in mid-spermatogenesis testis stage. In all the investigated gonadal development stages, gene dmrt1 and hsd11b2 were expressed higher in male whereas foxl2 and cyp19a1 were expressed higher in female. Thus, these genes provided the promising markers for sex identification of sterlet. It was unexpected that dkk1 and dax1 had significantly higher expression in ovarian perinucleolus stage than in ovarian chromatin nucleolus stage and in the testis, suggesting that these two genes had more correlation with ovarian development than with the testis, contrary to the previous reports in other vertebrates. Testicular development-related genes (gsdf and amh) and estrogen receptor genes (era and erb) differentially expressed at different testis or ovary development stages, but their expressions were not absolutely significantly different in male and female, depending on the gonadal development stage. Expression of androgen receptor gene ar or rspo, which was supposed to be related to ovarian development, presented no difference between gonadal development stages investigated in this study whenever in male or female.

Identification and Characterization of Genomic Amplifications in Ovarian Serous Carcinoma

DTIC Science & Technology

2009-07-01

oncogenes, Rsf1 and Notch3, which were up-regulated in both genomic DNA and transcript levels in ovarian cancer. In a large- scale FISH analysis, Rsf1...associated with worse disease outcome, suggesting that Rsf1 could be potentially used as a prognostic marker in the future (Appendix #1). For the...over- expressed in a recurrent carcinoma. Although the follow-up study in a larger- scale sample size did not demonstrate clear amplification in NAC1

High capacity for extracellular acid-base regulation in the air-breathing fish Pangasianodon hypophthalmus.

PubMed

Damsgaard, Christian; Gam, Le Thi Hong; Tuong, Dang Diem; Thinh, Phan Vinh; Huong Thanh, Do Thi; Wang, Tobias; Bayley, Mark

2015-05-01

The evolution of accessory air-breathing structures is typically associated with reduction of the gills, although branchial ion transport remains pivotal for acid-base and ion regulation. Therefore, air-breathing fishes are believed to have a low capacity for extracellular pH regulation during a respiratory acidosis. In the present study, we investigated acid-base regulation during hypercapnia in the air-breathing fish Pangasianodon hypophthalmus in normoxic and hypoxic water at 28-30°C. Contrary to previous studies, we show that this air-breathing fish has a pronounced ability to regulate extracellular pH (pHe) during hypercapnia, with complete metabolic compensation of pHe within 72 h of exposure to hypoxic hypercapnia with CO2 levels above 34 mmHg. The high capacity for pHe regulation relies on a pronounced ability to increase levels of HCO3(-) in the plasma. Our study illustrates the diversity in the physiology of air-breathing fishes, such that generalizations across phylogenies may be difficult. © 2015. Published by The Company of Biologists Ltd.

Gene expression underlying enhanced, steroid-dependent auditory sensitivity of hair cell epithelium in a vocal fish.

PubMed

Fergus, Daniel J; Feng, Ni Y; Bass, Andrew H

2015-10-14

Successful animal communication depends on a receiver's ability to detect a sender's signal. Exemplars of adaptive sender-receiver coupling include acoustic communication, often important in the context of seasonal reproduction. During the reproductive summer season, both male and female midshipman fish (Porichthys notatus) exhibit similar increases in the steroid-dependent frequency sensitivity of the saccule, the main auditory division of the inner ear. This form of auditory plasticity enhances detection of the higher frequency components of the multi-harmonic, long-duration advertisement calls produced repetitively by males during summer nights of peak vocal and spawning activity. The molecular basis of this seasonal auditory plasticity has not been fully resolved. Here, we utilize an unbiased transcriptomic RNA sequencing approach to identify differentially expressed transcripts within the saccule's hair cell epithelium of reproductive summer and non-reproductive winter fish. We assembled 74,027 unique transcripts from our saccular epithelial sequence reads. Of these, 6.4 % and 3.0 % were upregulated in the reproductive and non-reproductive saccular epithelium, respectively. Gene ontology (GO) term enrichment analyses of the differentially expressed transcripts showed that the reproductive saccular epithelium was transcriptionally, translationally, and metabolically more active than the non-reproductive epithelium. Furthermore, the expression of a specific suite of candidate genes, including ion channels and components of steroid-signaling pathways, was upregulated in the reproductive compared to the non-reproductive saccular epithelium. We found reported auditory functions for 14 candidate genes upregulated in the reproductive midshipman saccular epithelium, 8 of which are enriched in mouse hair cells, validating their hair cell-specific functions across vertebrates. We identified a suite of differentially expressed genes belonging to neurotransmission and steroid-signaling pathways, consistent with previous work showing the importance of these characters in regulating hair cell auditory sensitivity in midshipman fish and, more broadly, vertebrates. The results were also consistent with auditory hair cells being generally more physiologically active when animals are in a reproductive state, a time of enhanced sensory-motor coupling between the auditory periphery and the upper harmonics of vocalizations. Together with several new candidate genes, our results identify discrete patterns of gene expression linked to frequency- and steroid-dependent plasticity of hair cell auditory sensitivity.

75 FR 56359 - 2010-2011 Refuge-Specific Hunting and Sport Fishing Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-15

...The Fish and Wildlife Service proposes to add one refuge to the list of areas open for hunting and/or sport fishing and increase the activities available at seven other refuges, along with pertinent refuge-specific regulations on other refuges that pertain to migratory game bird hunting, upland game hunting, big game hunting, and sport fishing for the 2010-2011 season.

The B7 family of immunoregulatory receptors: A comparative and evolutionary perspective

USGS Publications Warehouse

Hansen, J.D.; Pasquier, L.D.; Lefranc, M.-P.; Lopez, V.; Benmansour, A.; Boudinot, P.

2009-01-01

In mammals, T cell activation requires specific recognition of the peptide-MHC complex by the TcR and co-stimulatory signals. Important co-stimulatory receptors expressed by T cells are the molecules of the CD28 family, that regulate T cell activation, proliferation and tolerance. These receptors recognize B7s and B7-homologous (B7H) molecules that are typically expressed by the antigen presenting cells. In teleost fish, typical T cell responses have been described and the TcR, MHC and CD28/CTLA4 genes have been characterized. In contrast, the members of the B7 gene family have only been described in mammals and birds and have yet to be addressed in lower vertebrates. To learn more about the evolution of components guiding T cell activation in vertebrates, we performed a systematic genomic survey for the B7 co-stimulatory and co-inhibitory IgSF receptors in lower vertebrates with an emphasis on teleost fish. Our search identified fish sequences that are orthologous to B7, B7-H1/B7-DC, B7-H3 and B7-H4 as defined by sequence identity, phylogeny and combinations of short or long-range syntenic relationships. However, we were unable to identify clear orthologs for B7-H2 (CD275, ICOS ligand) in bony fish, which correlates with our prior inability to find ICOS in fish. Interestingly, our results indicate that teleost fish possess a single B7.1/B7.2 (CD80/86) molecule that likely interacts with CD28/CTLA4 as the ligand-binding regions seem to be conserved in both partners. Overall, our analyses implies that gene duplication (and loss) have shaped a molecular repertoire of B7-like molecules that was recruited for the refinement of T cell activation during the evolution of the vertebrates.

Aryl hydrocarbon receptor function in early vertebrates:Inducibility of cytochrome P450 1A in agnathan and elasmobranch fish

USGS Publications Warehouse

Hahn, Mark E.; Woodin, Bruce R.; Stegeman, John J.; Tillitt, Donald E.

1998-01-01

The mammalian aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that controls the expression of cytochrome P450 1A (CYP1A) genes in response to halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The natural ligand and normal physiologic function of this protein are as yet unknown. One approach to understanding AHR function and significance is to determine the evolutionary history of this receptor and of processes such as CYP1A induction that are controlled by the AHR in mammals. In these studies, AHR function was evaluated in representative cartilaginous fish (little skate, Raja erinacea) and jawless fish (sea lamprey, Petromyzon marinus and Atlantic hagfish, Myxine glutinosa), using CYP1A induction as a model AHR-dependent response. Treatment of skate with β-naphthoflavone (BNF) caused an 8-fold increase in hepatic ethoxyresorufin O-deethylase (EROD) activity as well as a 37-fold increase in the content of immunodetectable CYP1A protein. Evidence of CYP1A inducibility was also obtained for another cartilaginous fish, the smooth dogfish Mustelus canis. In contrast, hepatic EROD activity was not detected in untreated lamprey nor in lamprey treated with 3,3′,4,4′-tetrachlorobiphenyl (TCB), a potent AHR agonist in teleosts. A possible CYP1A homolog was detected in lamprey hepatic microsomes by one of three antibodies to teleost CYP1A, but expression of this protein was not altered by TCB treatment. CYP1A protein and catalytic activity were measurable in hagfish, but neither was induced after treatment with TCB. These results suggest that the AHR-CYP1A signal transduction pathway is highly conserved in gnathostomes, but that there may be fundamental differences in AHR signaling or AHR-CYP1A coupling in agnathan fish. Agnathan fish such as hagfish and lamprey may be interesting model species for examining possible ancestral AHR functions not related to CYP1A regulation.

Evaluation of a high-EPA oil from transgenic Camelina sativa in feeds for Atlantic salmon (Salmo salar L.): Effects on tissue fatty acid composition, histology and gene expression.

PubMed

Betancor, M B; Sprague, M; Sayanova, O; Usher, S; Campbell, P J; Napier, J A; Caballero, M J; Tocher, D R

2015-07-01

Currently, one alternative for dietary fish oil (FO) in aquafeeds is vegetable oils (VO) that are devoid of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs). Entirely new sources of n-3 LC-PUFA such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids through de novo production are a potential solution to fill the gap between supply and demand of these important nutrients. Camelina sativa was metabolically engineered to produce a seed oil (ECO) with > 20% EPA and its potential to substitute for FO in Atlantic salmon feeds was tested. Fish were fed with one of the three experimental diets containing FO, wild-type camelina oil (WCO) or ECO as the sole lipid sources for 7 weeks. Inclusion of ECO did not affect any of the performance parameters studied and enhanced apparent digestibility of individual n-6 and n-3 PUFA compared to dietary WCO. High levels of EPA were maintained in brain, liver and intestine (pyloric caeca), and levels of DPA and DHA were increased in liver and intestine of fish fed ECO compared to fish fed WCO likely due to increased LC-PUFA biosynthesis based on up-regulation of the genes. Fish fed ECO showed slight lipid accumulation within hepatocytes similar to that with WCO, although not significantly different to fish fed FO. The regulation of a small number of genes could be attributed to the specific effect of ECO (311 features) with metabolism being the most affected category. The EPA oil from transgenic Camelina (ECO) could be used as a substitute for FO, however it is a hybrid oil containing both FO (EPA) and VO (18:2n-6) fatty acid signatures that resulted in similarly mixed metabolic and physiological responses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yokoo, Masako; Fujita, Ryosuke; Innate Immunity Laboratory, Graduate School of Life Science and Creative Research Institution, Hokkaido University, Sapporo 001-0021

Highlights: •The baculovirus vector infiltrates the cells of economic important fishes. •Drosophila Mos1 transposase expressed in fish cells maintains its ability to localize to the nucleus. •The baculoviral vector carrying Mos1 is a useful tool to stably transform fish cells. -- Abstract: Drosophila Mos1 belongs to the mariner family of transposons, which are one of the most ubiquitous transposons among eukaryotes. We first determined nuclear transportation of the Drosophila Mos1-EGFP fusion protein in fish cell lines because it is required for a function of transposons. We next constructed recombinant baculoviral vectors harboring the Drosophila Mos1 transposon or marker genes locatedmore » between Mos1 inverted repeats. The infectivity of the recombinant virus to fish cells was assessed by monitoring the expression of a fluorescent protein encoded in the viral genome. We detected transgene expression in CHSE-214, HINAE, and EPC cells, but not in GF or RTG-2 cells. In the co-infection assay of the Mos1-expressing virus and reporter gene-expressing virus, we successfully transformed CHSE-214 and HINAE cells. These results suggest that the combination of a baculovirus and Mos1 transposable element may be a tool for transgenesis in fish cells.« less

Acidic digestion in a teleost: postprandial and circadian pattern of gastric pH, pepsin activity, and pepsinogen and proton pump mRNAs expression.

PubMed

Yúfera, Manuel; Moyano, Francisco J; Astola, Antonio; Pousão-Ferreira, Pedro; Martínez-Rodríguez, Gonzalo

2012-01-01

Two different modes for regulation of stomach acid secretion have been described in vertebrates. Some species exhibit a continuous acid secretion maintaining a low gastric pH during fasting. Others, as some teleosts, maintain a neutral gastric pH during fasting while the hydrochloric acid is released only after the ingestion of a meal. Those different patterns seem to be closely related to specific feeding habits. However, our recent observations suggest that this acidification pattern could be modified by changes in daily feeding frequency and time schedule. The aim of this study was to advance in understanding the regulation mechanisms of stomach digestion and pattern of acid secretion in teleost fish. We have examined the postprandial pattern of gastric pH, pepsin activity, and mRNA expression for pepsinogen and proton pump in white seabream juveniles maintained under a light/dark 12/12 hours cycle and receiving only one morning meal. The pepsin activity was analyzed according to the standard protocol buffering at pH 2 and using the actual pH measured in the stomach. The results show how the enzyme precursor is permanently available while the hydrochloric acid, which activates the zymogen fraction, is secreted just after the ingestion of food. Results also reveal that analytical protocol at pH 2 notably overestimates true pepsin activity in fish stomach. The expression of the mRNA encoding pepsinogen and proton pump exhibited almost parallel patterns, with notable increases during the darkness period and sharp decreases just before the morning meal. These results indicate that white seabream uses the resting hours for recovering the mRNA stock that will be quickly used during the feeding process. Our data clearly shows that both daily illumination pattern and feeding time are involved at different level in the regulation of the secretion of digestive juices.

Development of siRNA expression vector utilizing rock bream beta-actin promoter: a potential therapeutic tool against viral infection in fish.

PubMed

Zenke, Kosuke; Nam, Yoon Kwon; Kim, Ki Hong

2010-01-01

In the present study, we have developed short interfering RNA (siRNA) expression vector utilizing rock bream beta-actin promoter and examined the possible use for the inhibition of highly pathogenic fish virus, rock bream iridovirus (RBIV), replication in vitro. Initially, in order to express siRNA effectively, we added several modifications to wild-type rock bream beta-actin promoter. Next, we succeeded in knocking down the expression of enhanced green fluorescent protein reporter gene expression in fish cells using newly developed vector more effectively than the fugu U6 promoter-driven vector we described previously. Finally, we could observe that cells transfected with modified rock bream beta-actin promoter-driven siRNA expression vector targeting major capsid protein (MCP) gene of RBIV exhibited more resistance to RBIV challenge than other control cells. Our results indicate that this novel siRNA expression vector can be used as a new tool for therapeutics in virus infection in fish species.