Claudins in teleost fishes

PubMed Central

Kolosov, Dennis; Bui, Phuong; Chasiotis, Helen; Kelly, Scott P

2013-01-01

Teleost fishes are a large and diverse animal group that represent close to 50% of all described vertebrate species. This review consolidates what is known about the claudin (Cldn) family of tight junction (TJ) proteins in teleosts. Cldns are transmembrane proteins of the vertebrate epithelial/endothelial TJ complex that largely determine TJ permeability. Cldns achieve this by expressing barrier or pore forming properties and by exhibiting distinct tissue distribution patterns. So far, ~63 genes encoding for Cldn TJ proteins have been reported in 16 teleost species. Collectively, cldns (or Cldns) are found in a broad array of teleost fish tissues, but select genes exhibit restricted expression patterns. Evidence to date strongly supports the view that Cldns play a vital role in the embryonic development of teleost fishes and in the physiology of tissues and organ systems studied thus far. PMID:24665402

Rapid evolution of piRNA pathway in the teleost fish: implication for an adaptation to transposon diversity.

PubMed

Yi, Minhan; Chen, Feng; Luo, Majing; Cheng, Yibin; Zhao, Huabin; Cheng, Hanhua; Zhou, Rongjia

2014-05-19

The Piwi-interacting RNA (piRNA) pathway is responsible for germline specification, gametogenesis, transposon silencing, and genome integrity. Transposable elements can disrupt genome and its functions. However, piRNA pathway evolution and its adaptation to transposon diversity in the teleost fish remain unknown. This article unveils evolutionary scene of piRNA pathway and its association with diverse transposons by systematically comparative analysis on diverse teleost fish genomes. Selective pressure analysis on piRNA pathway and miRNA/siRNA (microRNA/small interfering RNA) pathway genes between teleosts and mammals showed an accelerated evolution of piRNA pathway genes in the teleost lineages, and positive selection on functional PAZ (Piwi/Ago/Zwille) and Tudor domains involved in the Piwi-piRNA/Tudor interaction, suggesting that the amino acid substitutions are adaptive to their functions in piRNA pathway in the teleost fish species. Notably five piRNA pathway genes evolved faster in the swamp eel, a kind of protogynous hermaphrodite fish, than the other teleosts, indicating a differential evolution of piRNA pathway between the swamp eel and other gonochoristic fishes. In addition, genome-wide analysis showed higher diversity of transposons in the teleost fish species compared with mammals. Our results suggest that rapidly evolved piRNA pathway in the teleost fish is likely to be involved in the adaption to transposon diversity. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

New Insights into Ligand-Receptor Pairing and Coevolution of Relaxin Family Peptides and Their Receptors in Teleosts

PubMed Central

Good, Sara; Yegorov, Sergey; Martijn, Joran; Franck, Jens; Bogerd, Jan

2012-01-01

Relaxin-like peptides (RLN/INSL) play diverse roles in reproductive and neuroendocrine processes in placental mammals and are functionally associated with two distinct types of receptors (RXFP) for each respective function. The diversification of RLN/INSL and RXFP gene families in vertebrates was predominantly driven by whole genome duplications (2R and 3R). Teleosts preferentially retained duplicates of genes putatively involved in neuroendocrine regulation, harboring a total of 10-11 receptors and 6 ligand genes, while most mammals have equal numbers of ligands and receptors. To date, the ligand-receptor relationships of teleost Rln/Insl peptides and their receptors have largely remained unexplored. Here, we use selection analyses based on sequence data from 5 teleosts and qPCR expression data from zebrafish to explore possible ligand-receptor pairings in teleosts. We find support for the hypothesis that, with the exception of RLN, which has undergone strong positive selection in mammalian lineages, the ligand and receptor genes shared between mammals and teleosts appear to have similar pairings. On the other hand, the teleost-specific receptors show evidence of subfunctionalization. Overall, this study underscores the complexity of RLN/INSL and RXFP ligand-receptor interactions in teleosts and establishes theoretical background for further experimental work in nonmammals. PMID:23008798

Island vs. countryside biogeography: an examination of how Amazonian birds respond to forest clearing and fragmentation

Treesearch

Jared D. Wolfe; Philip C. Stouffer; Karl Mokross; Luke L. Powell; Marina M. Anciães

2015-01-01

Avian diversity in fragmented Amazonian landscapes depends on a balance between extinction and colonization in cleared and disturbed areas. Regenerating forest facilitates bird dispersal within degraded Amazonian landscapes and may tip the balance in favor of persistence in habitat patches. Determining the response of Amazonian birds to fragmentation may be...

Descending pathways to the spinal cord in teleosts in comparison with mammals, with special attention to rubrospinal pathways.

PubMed

Yamamoto, Naoyuki; Nakayama, Tomoya; Hagio, Hanako

2017-05-01

In this article we review descending neural pathways to the spinal cord in teleosts, compared with mammals. Descending pathways to the spinal cord are crucial in controlling various behaviors in vertebrates. The major difference between teleosts and mammals is the lack of corticospinal (or palliospinal) tracts. Other descending pathways, which originate from the brain stem, are basically identical in teleosts and mammals. This suggests the presence of common systems in the spinal motor control by higher order centers. The homologue of nucleus ruber remained unclear in teleosts until recently, and this review pays special attention to the rubrospinal tract. © 2017 Japanese Society of Developmental Biologists.

Expansion by whole genome duplication and evolution of the sox gene family in teleost fish

PubMed Central

Naville, Magali; Volff, Jean-Nicolas

2017-01-01

It is now recognized that several rounds of whole genome duplication (WGD) have occurred during the evolution of vertebrates, but the link between WGDs and phenotypic diversification remains unsolved. We have investigated in this study the impact of the teleost-specific WGD on the evolution of the sox gene family in teleostean fishes. The sox gene family, which encodes for transcription factors, has essential role in morphology, physiology and behavior of vertebrates and teleosts, the current largest group of vertebrates. We have first redrawn the evolution of all sox genes identified in eleven teleost genomes using a comparative genomic approach including phylogenetic and synteny analyses. We noticed, compared to tetrapods, an important expansion of the sox family: 58% (11/19) of sox genes are duplicated in teleost genomes. Furthermore, all duplicated sox genes, except sox17 paralogs, are derived from the teleost-specific WGD. Then, focusing on five sox genes, analyzing the evolution of coding and non-coding sequences, as well as the expression patterns in fish embryos and adult tissues, we demonstrated that these paralogs followed lineage-specific evolutionary trajectories in teleost genomes. This work, based on whole genome data from multiple teleostean species, supports the contribution of WGDs to the expansion of gene families, as well as to the emergence of genomic differences between lineages that might promote genetic and phenotypic diversity in teleosts. PMID:28738066

The spotted gar genome illuminates vertebrate evolution and facilitates human-teleost comparisons.

PubMed

Braasch, Ingo; Gehrke, Andrew R; Smith, Jeramiah J; Kawasaki, Kazuhiko; Manousaki, Tereza; Pasquier, Jeremy; Amores, Angel; Desvignes, Thomas; Batzel, Peter; Catchen, Julian; Berlin, Aaron M; Campbell, Michael S; Barrell, Daniel; Martin, Kyle J; Mulley, John F; Ravi, Vydianathan; Lee, Alison P; Nakamura, Tetsuya; Chalopin, Domitille; Fan, Shaohua; Wcisel, Dustin; Cañestro, Cristian; Sydes, Jason; Beaudry, Felix E G; Sun, Yi; Hertel, Jana; Beam, Michael J; Fasold, Mario; Ishiyama, Mikio; Johnson, Jeremy; Kehr, Steffi; Lara, Marcia; Letaw, John H; Litman, Gary W; Litman, Ronda T; Mikami, Masato; Ota, Tatsuya; Saha, Nil Ratan; Williams, Louise; Stadler, Peter F; Wang, Han; Taylor, John S; Fontenot, Quenton; Ferrara, Allyse; Searle, Stephen M J; Aken, Bronwen; Yandell, Mark; Schneider, Igor; Yoder, Jeffrey A; Volff, Jean-Nicolas; Meyer, Axel; Amemiya, Chris T; Venkatesh, Byrappa; Holland, Peter W H; Guiguen, Yann; Bobe, Julien; Shubin, Neil H; Di Palma, Federica; Alföldi, Jessica; Lindblad-Toh, Kerstin; Postlethwait, John H

2016-04-01

To connect human biology to fish biomedical models, we sequenced the genome of spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before teleost genome duplication (TGD). The slowly evolving gar genome has conserved in content and size many entire chromosomes from bony vertebrate ancestors. Gar bridges teleosts to tetrapods by illuminating the evolution of immunity, mineralization and development (mediated, for example, by Hox, ParaHox and microRNA genes). Numerous conserved noncoding elements (CNEs; often cis regulatory) undetectable in direct human-teleost comparisons become apparent using gar: functional studies uncovered conserved roles for such cryptic CNEs, facilitating annotation of sequences identified in human genome-wide association studies. Transcriptomic analyses showed that the sums of expression domains and expression levels for duplicated teleost genes often approximate the patterns and levels of expression for gar genes, consistent with subfunctionalization. The gar genome provides a resource for understanding evolution after genome duplication, the origin of vertebrate genomes and the function of human regulatory sequences.

The spotted gar genome illuminates vertebrate evolution and facilitates human-to-teleost comparisons

PubMed Central

Braasch, Ingo; Gehrke, Andrew R.; Smith, Jeramiah J.; Kawasaki, Kazuhiko; Manousaki, Tereza; Pasquier, Jeremy; Amores, Angel; Desvignes, Thomas; Batzel, Peter; Catchen, Julian; Berlin, Aaron M.; Campbell, Michael S.; Barrell, Daniel; Martin, Kyle J.; Mulley, John F.; Ravi, Vydianathan; Lee, Alison P.; Nakamura, Tetsuya; Chalopin, Domitille; Fan, Shaohua; Wcisel, Dustin; Cañestro, Cristian; Sydes, Jason; Beaudry, Felix E. G.; Sun, Yi; Hertel, Jana; Beam, Michael J.; Fasold, Mario; Ishiyama, Mikio; Johnson, Jeremy; Kehr, Steffi; Lara, Marcia; Letaw, John H.; Litman, Gary W.; Litman, Ronda T.; Mikami, Masato; Ota, Tatsuya; Saha, Nil Ratan; Williams, Louise; Stadler, Peter F.; Wang, Han; Taylor, John S.; Fontenot, Quenton; Ferrara, Allyse; Searle, Stephen M. J.; Aken, Bronwen; Yandell, Mark; Schneider, Igor; Yoder, Jeffrey A.; Volff, Jean-Nicolas; Meyer, Axel; Amemiya, Chris T.; Venkatesh, Byrappa; Holland, Peter W. H.; Guiguen, Yann; Bobe, Julien; Shubin, Neil H.; Di Palma, Federica; Alföldi, Jessica; Lindblad-Toh, Kerstin; Postlethwait, John H.

2016-01-01

To connect human biology to fish biomedical models, we sequenced the genome of spotted gar (Lepisosteus oculatus), whose lineage diverged from teleosts before the teleost genome duplication (TGD). The slowly evolving gar genome conserved in content and size many entire chromosomes from bony vertebrate ancestors. Gar bridges teleosts to tetrapods by illuminating the evolution of immunity, mineralization, and development (e.g., Hox, ParaHox, and miRNA genes). Numerous conserved non-coding elements (CNEs, often cis-regulatory) undetectable in direct human-teleost comparisons become apparent using gar: functional studies uncovered conserved roles of such cryptic CNEs, facilitating annotation of sequences identified in human genome-wide association studies. Transcriptomic analyses revealed that the sum of expression domains and levels from duplicated teleost genes often approximate patterns and levels of gar genes, consistent with subfunctionalization. The gar genome provides a resource for understanding evolution after genome duplication, the origin of vertebrate genomes, and the function of human regulatory sequences. PMID:26950095

The Physiology Teacher, Vol. 5 No. 1.

ERIC Educational Resources Information Center

Reynolds, Orr E., Ed.

Outlined in this publication is a basic laboratory exercise which characterizes tubular secretion, using an isolated renal tubule preparation from teleost fish. Background information is given showing how these tubules of teleost fish, particularly marine teleosts, correspond to the proximal tubule of mammalian kidney. Materials needed, including…

Dietary variations within a family of ambush predators (Platycephalidae) occupying different habitats and environments in the same geographical region.

PubMed

Coulson, P G; Platell, M E; Clarke, K R; Potter, I C

2015-03-01

This study has determined the extents and basis for variations in the composition of the prey ingested by the abundant species of a family highly adapted for ambush predation, i.e. Platycephalidae, in a region (south-western Australia) where that family is found in different habitats and environments. Dietary data were thus collected for Leviprora inops and Platycephalus laevigatus from seagrass in marine embayments and for Platycephalus westraliae from over sand in an estuary. These were then collated with those recorded previously for Platycephalus speculator from over sand and in seagrass in an estuary and for Platycephalus longispinis from over sand in coastal marine waters. While crustaceans and teleosts together dominated the diet of all five species, their percentage volumetric dietary contributions varied greatly, with those of crustaceans ranging from 7% for L. inops to 65% for P. speculator and those of teleosts ranging from 29% for P. longispinis to 91% for L. inops. For analyses, the data were separated into two sets. The first comprised the 17 dietary categories of invertebrates and all identified and unidentified teleosts collectively, while the second consisted of the 23 identified teleost families, both of which were subjected to permutational analysis of variance (PERMANOVA), analysis of similarities (ANOSIM) and a new (two-way) version of the RELATE procedure. The diets of three species changed seasonally, when using invertebrate dietary categories and teleosts collectively, but with only one species, when employing identified teleost families, probably reflecting a greater tendency for invertebrate than teleost prey abundance to change during the year. On the basis of dietary data for invertebrate taxa + teleosts collectively, the diets of three of the five species changed serially with body size, with a fourth species feeding, throughout life, predominantly on the carid Palaemonetes australis. Based on identified teleost families, the diets of the three species that fed predominantly on teleosts underwent serial size-related changes. Although L. inops and the co-occurring P. laevigatus both consume large volumes of teleosts, the former ingests larger, less demersal and more mobile prey, e.g. the labrids Haletta semifasciata and Neoodax balteatus, than the latter, e.g. the scorpaenid Gymnapistes marmoratus, reflecting the possession by L. inops of a far longer head and larger buccal cavity. Circumstantial evidence suggests that the large differences in the volumes of crustaceans and teleosts consumed by each platycephalid species are related to differences in the relative availability of these prey in the different habitats or environments of each species. © 2015 The Fisheries Society of the British Isles.

Implications for osmorespiratory compromise by anatomical remodeling in the gills of Arapaima gigas.

PubMed

Ramos, Cleverson Agner; Fernandes, Marisa Narciso; da Costa, Oscar Tadeu Ferreira; Duncan, Wallice Paxiuba

2013-10-01

The gill structure of the Amazonian fish Arapaima gigas, an obligatory air breather, was investigated during its transition from water breathing to the obligatory air breathing modes of respiration. The gill structure of A. gigas larvae is similar to that of most teleost fish; however, the morphology of the gills changes as the fish grow. The main morphological changes in the gill structure of a growing fish include the following: (1) intense cell proliferation in the filaments and lamellae, resulting in increasing epithelial thickness and decreasing interlamellar distance; (2) pillar cell system atrophy, which reduces the blood circulation through the lamellae; (3) the generation of long cytoplasmic processes from the epithelial cells into the intercellular space, resulting in continuous and sinuous paracellular channels between the epithelial cells of the filament and lamella that may be involved in gas, ion, and nutrient transport to epithelial cells; and (4) intense mitochondria-rich cell (MRC) proliferation in the lamellar epithelium. All of these morphological changes in the gills contribute to a low increase of the respiratory surface area for gas exchange and an increase in the water-blood diffusion distance increasing their dependence on air-breathing as fish developed. The increased proliferation of MRCs may contribute to increased ion uptake, which favors the regulation of ion content and pH equilibrium. Copyright © 2013 Wiley Periodicals, Inc.

Breakup of a homeobox cluster after genome duplication in teleosts

PubMed Central

Mulley, John F.; Chiu, Chi-hua; Holland, Peter W. H.

2006-01-01

Several families of homeobox genes are arranged in genomic clusters in metazoan genomes, including the Hox, ParaHox, NK, Rhox, and Iroquois gene clusters. The selective pressures responsible for maintenance of these gene clusters are poorly understood. The ParaHox gene cluster is evolutionarily conserved between amphioxus and human but is fragmented in teleost fishes. We show that two basal ray-finned fish, Polypterus and Amia, each possess an intact ParaHox cluster; this implies that the selective pressure maintaining clustering was lost after whole-genome duplication in teleosts. Cluster breakup is because of gene loss, not transposition or inversion, and the total number of ParaHox genes is the same in teleosts, human, mouse, and frog. We propose that this homeobox gene cluster is held together in chordates by the existence of interdigitated control regions that could be separated after locus duplication in the teleost fish. PMID:16801555

The role of branchial and orobranchial O2 chemoreceptors in the control of aquatic surface respiration in the neotropical fish tambaqui (Colossoma macropomum): progressive responses to prolonged hypoxia.

PubMed

Florindo, Luiz H; Leite, Cléo A C; Kalinin, Ana L; Reid, Stephen G; Milsom, William K; Rantin, F Tadeu

2006-05-01

The present study examined the role of branchial and orobranchial O(2) chemoreceptors in the cardiorespiratory responses, aquatic surface respiration (ASR), and the development of inferior lip swelling in tambaqui during prolonged (6 h) exposure to hypoxia. Intact fish (control) and three groups of denervated fish (bilateral denervation of cranial nerves IX+X (to the gills), of cranial nerves V+VII (to the orobranchial cavity) or of cranial nerves V alone), were exposed to severe hypoxia (Pw(O)2=10 mmHg) for 360 min. Respiratory frequency (fr) and heart rate (fh) were recorded simultaneously with ASR. Intact (control) fish increased fr, ventilation amplitude (V(AMP)) and developed hypoxic bradycardia in the first 60 min of hypoxia. The bradycardia, however, abated progressively and had returned to normoxic levels by the last hour of exposure to hypoxia. The changes in respiratory frequency and the hypoxic bradycardia were eliminated by denervation of cranial nerves IX and X but were not affected by denervation of cranial nerves V or V+VII. The V(AMP) was not abolished by the various denervation protocols. The fh in fish with denervation of cranial nerves V or V+VII, however, did not recover to control values as in intact fish. After 360 min of exposure to hypoxia only the intact and IX+X denervated fish performed ASR. Denervation of cranial nerve V abolished the ASR behavior. However, all (control and denervated (IX+X, V and V+VII) fish developed inferior lip swelling. These results indicate that ASR is triggered by O(2) chemoreceptors innervated by cranial nerve V but that other mechanisms, such as a direct effect of hypoxia on the lip tissue, trigger lip swelling.

Macroglial cells of the teleost central nervous system: a survey of the main types.

PubMed

Cuoghi, Barbara; Mola, Lucrezia

2009-12-01

Following our previous review of teleost microglia, we focus here on the morphological and histochemical features of the three principal macroglia types in the teleost central nervous system (ependymal cells, astrocyte-like cells/radial glia and oligodendrocytes). This review is concerned with recent literature and not only provides insights into the various individual aspects of the different types of macroglial cells plus a comparison with mammalian glia, but also indicates the several potentials that the neural tissue of teleosts exhibits in neurobiological research. Indeed, some areas of the teleost brain are particularly suitable in terms of the establishment of a "simple" but complete research model (i.e. the visual pathway complex and the supramedullary neuron cluster in puffer fish). The relationships between neurons and glial cells are considered in fish, with the aim of providing an integrated picture of the complex ways in which neurons and glia communicate and collaborate in normal and injured neural tissues. The recent setting up of successful protocols for fish glia and mixed neuron-glia cultures, together with the molecular facilities offered by the knowledge of some teleost genomes, should allow consistent input towards the achievement of this aim.

Voices of Contact: Politics of Language in Urban Amazonian Ecuador

ERIC Educational Resources Information Center

Wroblewski, Michael

2010-01-01

This dissertation is a study of diverse linguistic resources and contentious identity politics among indigenous Amazonian Kichwas in the city of Tena, Ecuador. Tena is a rapidly developing Amazonian provincial capital city with a long history of interethnic and interlinguistic contact. In recent decades, the course of indigenous Kichwa identity…

The Mission of the Amazonian Universities in Economic Development and Environmental Preservation.

ERIC Educational Resources Information Center

Lourenco, Jose Seixas

The Association of Amazonian Universities (UNAMAZ) was created in September 1987 and is involved in a collective effort to find ways to promote the Amazonian region's nonpredatory development, recognizing its limitations and taking into account its potential. With deforestation taking place at ever-increasing speed, it has become necessary to…

Evolution of caudal fin ray development and caudal fin hypural diastema complex in spotted gar, teleosts, and other neopterygian fishes.

PubMed

Desvignes, Thomas; Carey, Andrew; Postlethwait, John H

2018-06-01

The caudal fin of actinopterygians transitioned from a heterocercal dorsoventrally asymmetrical fin to a homocercal externally symmetrical fin in teleosts through poorly understood evolutionary developmental mechanisms. We studied the caudal skeleton of major living actinopterygian lineages, including polypteriformes, acipenseriformes, Holostei (gars and bowfin), and teleosts, compared with reports of extinct neopterygians and basal teleosteans. We focused on the hypural diastema complex, which includes (1) a gap between hypurals 2 and 3, that (2) separates two plates of connective tissue at (3) the branching of caudal vasculature; these features had been considered as a shared, derived trait of teleosts, a synapomorphy. These studies revealed that gars and teleosts share all three features of the hypural diastema complex. Absence of a complex with these features from bowfin, fossil Holostei, and stem Teleostei argues in favor of repetitive, independent emergence in several neopterygian and basal Teleostei lineages, or less likely, many independent losses. We further observed that, in gars and teleosts, the earliest developing lepidotrichia align with the horizontal adult body axis, thus participating in external symmetry. These results suggest that the hypural diastema complex in teleosts and gars represents a homoplasy among neopterygians and that it emerged repeatedly by parallel evolution due to shared inherited underlying genetic and developmental programs (latent homology). Because the hypural diastema complex exists in gars with heterocercal tails, this complex is independent of homocercality. Developmental Dynamics 247:832-853, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Comparative genomic organization and tissue-specific transcription of the duplicated fabp7 and fabp10 genes in teleost fishes.

PubMed

Parmar, Manoj B; Wright, Jonathan M

2013-11-01

A whole-genome duplication (WGD) early in the teleost fish lineage makes fish ideal organisms to study the fate of duplicated genes and underlying evolutionary trajectories that have led to the retention of ohnologous gene duplicates in fish genomes. Here, we compare the genomic organization and tissue-specific transcription of the ohnologous fabp7 and fabp10 genes in medaka, three-spined stickleback, and spotted green pufferfish to the well-studied duplicated fabp7 and fabp10 genes of zebrafish. Teleost fabp7 and fabp10 genes contain four exons interrupted by three introns. Polypeptide sequences of Fabp7 and Fabp10 show the highest sequence identity and similarity with their orthologs from vertebrates. Orthology was evident as the ohnologous Fabp7 and Fabp10 polypeptides of teleost fishes each formed distinct clades and clustered together with their orthologs from other vertebrates in a phylogenetic tree. Furthermore, ohnologous teleost fabp7 and fabp10 genes exhibit conserved gene synteny with human FABP7 and chicken FABP10, respectively, which provides compelling evidence that the duplicated fabp7 and fabp10 genes of teleost fishes most likely arose from the well-documented WGD. The tissue-specific distribution of fabp7a, fabp7b, fabp10a, and fabp10b transcripts provides evidence of diverged spatial transcriptional regulation between ohnologous gene duplicates of fabp7 and fabp10 in teleost fishes.

Whole-Genome Duplication and the Functional Diversification of Teleost Fish Hemoglobins

PubMed Central

Opazo, Juan C.; Butts, G. Tyler; Nery, Mariana F.; Storz, Jay F.; Hoffmann, Federico G.

2013-01-01

Subsequent to the two rounds of whole-genome duplication that occurred in the common ancestor of vertebrates, a third genome duplication occurred in the stem lineage of teleost fishes. This teleost-specific genome duplication (TGD) is thought to have provided genetic raw materials for the physiological, morphological, and behavioral diversification of this highly speciose group. The extreme physiological versatility of teleost fish is manifest in their diversity of blood–gas transport traits, which reflects the myriad solutions that have evolved to maintain tissue O2 delivery in the face of changing metabolic demands and environmental O2 availability during different ontogenetic stages. During the course of development, regulatory changes in blood–O2 transport are mediated by the expression of multiple, functionally distinct hemoglobin (Hb) isoforms that meet the particular O2-transport challenges encountered by the developing embryo or fetus (in viviparous or oviparous species) and in free-swimming larvae and adults. The main objective of the present study was to assess the relative contributions of whole-genome duplication, large-scale segmental duplication, and small-scale gene duplication in producing the extraordinary functional diversity of teleost Hbs. To accomplish this, we integrated phylogenetic reconstructions with analyses of conserved synteny to characterize the genomic organization and evolutionary history of the globin gene clusters of teleosts. These results were then integrated with available experimental data on functional properties and developmental patterns of stage-specific gene expression. Our results indicate that multiple α- and β-globin genes were present in the common ancestor of gars (order Lepisoteiformes) and teleosts. The comparative genomic analysis revealed that teleosts possess a dual set of TGD-derived globin gene clusters, each of which has undergone lineage-specific changes in gene content via repeated duplication and deletion events. Phylogenetic reconstructions revealed that paralogous genes convergently evolved similar functional properties in different teleost lineages. Consistent with other recent studies of globin gene family evolution in vertebrates, our results revealed evidence for repeated evolutionary transitions in the developmental regulation of Hb synthesis. PMID:22949522

Higher Education and Urban Migration for Community Resilience: Indigenous Amazonian Youth Promoting Place-Based Livelihoods and Identities in Peru

ERIC Educational Resources Information Center

Steele, Diana

2018-01-01

This paper offers an ethnographic analysis of indigenous Peruvian Amazonian youth pursuing higher education through urban migration to contribute to the resilience of their communities, place-based livelihoods, and indigenous Amazonian identities. Youth and their communities promoted education and migration as powerful tools in the context of…

Evolutionary diversity and turn-over of sex determination in teleost fishes.

PubMed

Mank, J E; Avise, J C

2009-01-01

Sex determination, due to the obvious association with reproduction and Darwinian fitness, has been traditionally assumed to be a relatively conserved trait. However, research on teleost fishes has shown that this need not be the case, as these animals display a remarkable diversity in the ways that they determine sex. These different mechanisms, which include constitutive genetic mechanisms on sex chromosomes, polygenic constitutive mechanisms, environmental influences, hermaphroditism, and unisexuality have each originated numerous independent times in the teleosts. The evolutionary lability of sex determination, and the corresponding rapid rate of turn-over among different modes, makes the teleost clade an excellent model with which to test theories regarding the evolution of sex determining adaptations. Much of the plasticity in sex determination likely results from the dynamic teleost genome, and recent advances in fish genetics and genomics have revealed the role of gene and genome duplication in fostering emergence and turn-over of sex determining mechanisms. 2009 S. Karger AG, Basel.

Steroids in teleost fishes: A functional point of view.

PubMed

Tokarz, Janina; Möller, Gabriele; Hrabě de Angelis, Martin; Adamski, Jerzy

2015-11-01

Steroid hormones are involved in the regulation of a variety of processes like embryonic development, sex differentiation, metabolism, immune responses, circadian rhythms, stress response, and reproduction in vertebrates. Teleost fishes and humans show a remarkable conservation in many developmental and physiological aspects, including the endocrine system in general and the steroid hormone related processes in particular. This review provides an overview of the current knowledge about steroid hormone biosynthesis and the steroid hormone receptors in teleost fishes and compares the findings to the human system. The impact of the duplicated genome in teleost fishes on steroid hormone biosynthesis and perception is addressed. Additionally, important processes in fish physiology regulated by steroid hormones, which are most dissimilar to humans, are described. We also give a short overview on the influence of anthropogenic endocrine disrupting compounds on steroid hormone signaling and the resulting adverse physiological effects for teleost fishes. By this approach, we show that the steroidogenesis, hormone receptors, and function of the steroid hormones are reasonably well understood when summarizing the available data of all teleost species analyzed to date. However, on the level of a single species or a certain fish-specific aspect of physiology, further research is needed. Copyright © 2015 Elsevier Inc. All rights reserved.

Rapid diversification of FoxP2 in teleosts through gene duplication in the teleost-specific whole genome duplication event.

PubMed

Song, Xiaowei; Wang, Yajun; Tang, Yezhong

2013-01-01

As one of the most conserved genes in vertebrates, FoxP2 is widely involved in a number of important physiological and developmental processes. We systematically studied the evolutionary history and functional adaptations of FoxP2 in teleosts. The duplicated FoxP2 genes (FoxP2a and FoxP2b), which were identified in teleosts using synteny and paralogon analysis on genome databases of eight organisms, were probably generated in the teleost-specific whole genome duplication event. A credible classification with FoxP2, FoxP2a and FoxP2b in phylogenetic reconstructions confirmed the teleost-specific FoxP2 duplication. The unavailability of FoxP2b in Danio rerio suggests that the gene was deleted through nonfunctionalization of the redundant copy after the Otocephala-Euteleostei split. Heterogeneity in evolutionary rates among clusters consisting of FoxP2 in Sarcopterygii (Cluster 1), FoxP2a in Teleostei (Cluster 2) and FoxP2b in Teleostei (Cluster 3), particularly between Clusters 2 and 3, reveals asymmetric functional divergence after the gene duplication. Hierarchical cluster analyses of hydrophobicity profiles demonstrated significant structural divergence among the three clusters with verification of subsequent stepwise discriminant analysis, in which FoxP2 of Leucoraja erinacea and Lepisosteus oculatus were classified into Cluster 1, whereas FoxP2b of Salmo salar was grouped into Cluster 2 rather than Cluster 3. The simulated thermodynamic stability variations of the forkhead box domain (monomer and homodimer) showed remarkable divergence in FoxP2, FoxP2a and FoxP2b clusters. Relaxed purifying selection and positive Darwinian selection probably were complementary driving forces for the accelerated evolution of FoxP2 in ray-finned fishes, especially for the adaptive evolution of FoxP2a and FoxP2b in teleosts subsequent to the teleost-specific gene duplication.

Rapid Diversification of FoxP2 in Teleosts through Gene Duplication in the Teleost-Specific Whole Genome Duplication Event

PubMed Central

Song, Xiaowei; Wang, Yajun; Tang, Yezhong

2013-01-01

As one of the most conserved genes in vertebrates, FoxP2 is widely involved in a number of important physiological and developmental processes. We systematically studied the evolutionary history and functional adaptations of FoxP2 in teleosts. The duplicated FoxP2 genes (FoxP2a and FoxP2b), which were identified in teleosts using synteny and paralogon analysis on genome databases of eight organisms, were probably generated in the teleost-specific whole genome duplication event. A credible classification with FoxP2, FoxP2a and FoxP2b in phylogenetic reconstructions confirmed the teleost-specific FoxP2 duplication. The unavailability of FoxP2b in Danio rerio suggests that the gene was deleted through nonfunctionalization of the redundant copy after the Otocephala-Euteleostei split. Heterogeneity in evolutionary rates among clusters consisting of FoxP2 in Sarcopterygii (Cluster 1), FoxP2a in Teleostei (Cluster 2) and FoxP2b in Teleostei (Cluster 3), particularly between Clusters 2 and 3, reveals asymmetric functional divergence after the gene duplication. Hierarchical cluster analyses of hydrophobicity profiles demonstrated significant structural divergence among the three clusters with verification of subsequent stepwise discriminant analysis, in which FoxP2 of Leucoraja erinacea and Lepisosteus oculatus were classified into Cluster 1, whereas FoxP2b of Salmo salar was grouped into Cluster 2 rather than Cluster 3. The simulated thermodynamic stability variations of the forkhead box domain (monomer and homodimer) showed remarkable divergence in FoxP2, FoxP2a and FoxP2b clusters. Relaxed purifying selection and positive Darwinian selection probably were complementary driving forces for the accelerated evolution of FoxP2 in ray-finned fishes, especially for the adaptive evolution of FoxP2a and FoxP2b in teleosts subsequent to the teleost-specific gene duplication. PMID:24349554

Teleost Fish-Specific Preferential Retention of Pigmentation Gene-Containing Families After Whole Genome Duplications in Vertebrates

PubMed Central

Lorin, Thibault; Brunet, Frédéric G.; Laudet, Vincent; Volff, Jean-Nicolas

2018-01-01

Vertebrate pigmentation is a highly diverse trait mainly determined by neural crest cell derivatives. It has been suggested that two rounds (1R/2R) of whole-genome duplications (WGDs) at the basis of vertebrates allowed changes in gene regulation associated with neural crest evolution. Subsequently, the teleost fish lineage experienced other WGDs, including the teleost-specific Ts3R before teleost radiation and the more recent Ss4R at the basis of salmonids. As the teleost lineage harbors the highest number of pigment cell types and pigmentation diversity in vertebrates, WGDs might have contributed to the evolution and diversification of the pigmentation gene repertoire in teleosts. We have compared the impact of the basal vertebrate 1R/2R duplications with that of the teleost-specific Ts3R and salmonid-specific Ss4R WGDs on 181 gene families containing genes involved in pigmentation. We show that pigmentation genes (PGs) have been globally more frequently retained as duplicates than other genes after Ts3R and Ss4R but not after the early 1R/2R. This is also true for non-pigmentary paralogs of PGs, suggesting that the function in pigmentation is not the sole key driver of gene retention after WGDs. On the long-term, specific categories of PGs have been repeatedly preferentially retained after ancient 1R/2R and Ts3R WGDs, possibly linked to the molecular nature of their proteins (e.g., DNA binding transcriptional regulators) and their central position in protein-protein interaction networks. Taken together, our results support a major role of WGDs in the diversification of the pigmentation gene repertoire in the teleost lineage, with a possible link with the diversity of pigment cell lineages observed in these animals compared to other vertebrates. PMID:29599177

Cloning of stanniocalcin (STC) cDNAs of divergent teleost species: Monomeric STC supports monophyly of the ancient teleosts, the osteoglossomorphs.

PubMed

Amemiya, Yutaka; Irwin, David M; Youson, John H

2006-10-01

Molecular cloning of teleost stanniocalcin (STC) cDNAs was undertaken in two species of order Osteoglossiformes of subdivision Osteoglossomorpha and one species of each of orders Cypriniformes and Perciformes within the subdivision Euteleostei. The elephantnose (Gnathonemus petersii) and the butterflyfish (Pantadon buchholzi) are basal teleosts in different osteoglossiforme suborders yet their 218 amino acid (aa) mature hormones, from prehormones of 249 and 251aa, respectively, have only 10 cysteine residues. A substitution for cysteine at the intermonomeric disulfide linkage site, implies that their STCs exist as monomeric peptides, as is the case with STC from another osteoglossormorph, arawana [Amemiya, Y., Marra, L.E., Reyhani, N., Youson, J.H., 2002. Stanniocalcin from an ancient teleost: a monomeric form of the hormone and a possible extracorpuscular distribution. Mol. Cell. Endocrinol. 188, 141-150]. The STC cDNA of the generalized teleost and cyprinid, the white sucker (Catostomus commersoni), encodes a prehormone of 249aa with a signal peptide of 31aa and a mature protein of 218aa that possesses 11 cysteine residues. The latter feature is consistent with a previous analysis that white sucker mature STC is a glycosylated, homodimeric peptide [Amemiya, Y., Marra, L.E., Reyhani, N., Youson, J.H., 2002. Stanniocalcin from an ancient teleost: a monomeric form of the hormone and a possible extracorpuscular distribution. Mol. Cell. Endocrinol. 188, 141-150]. An open reading frame of the STC cDNA of the derived teleost and perciforme, the smallmouth bass (Micropterus dolomieui), encodes a prehormone of 255aa with a signal peptide of 33aa and a mature protein of 222aa. The position of the 11 cysteines in smallmouth bass STC suggests that it exists as a homodimeric peptide. A phylogenetic analysis, using the new STC-1 amino acid sequences and those in the gene data base provided strong support for monophyly of the Osteoglossomorpha and indicated, with positioning of white sucker and smallmouth bass, that this molecule has some utility as a taxonomic marker. This analysis also suggested that two STC-1 gene sequences exist in multiple fish genomes, and that they may be a product of the fish-specific genome duplication. The mutation in the osteoglossomorph STC likely occurred after the appearance of the first teleosts and before movement of the tectonic plates.

Fatty acid-binding protein genes of the ancient, air-breathing, ray-finned fish, spotted gar (Lepisosteus oculatus).

PubMed

Venkatachalam, Ananda B; Fontenot, Quenton; Farrara, Allyse; Wright, Jonathan M

2018-03-01

With the advent of high-throughput DNA sequencing technology, the genomic sequence of many disparate species has led to the relatively new discipline of genomics, the study of genome structure, function and evolution. Much work has been focused on the role of whole genome duplications (WGD) in the architecture of extant vertebrate genomes, particularly those of teleost fishes which underwent a WGD early in the teleost radiation >230 million years ago (mya). Our past work has focused on the fate of duplicated copies of a multigene family coding for the intracellular lipid-binding protein (iLBP) genes in the teleost fishes. To define the evolutionary processes that determined the fate of duplicated genes and generated the structure of extant fish genomes, however, requires comparative genomic analysis with a fish lineage that diverged before the teleost WGD, such as the spotted gar (Lepisosteus oculatus), an ancient, air-breathing, ray-finned fish. Here, we describe the genomic organization, chromosomal location and tissue-specific expression of a subfamily of the iLBP genes that code for fatty acid-binding proteins (Fabps) in spotted gar. Based on this work, we have defined the minimum suite of fabp genes prior to their duplication in the teleost lineages ~230-400 mya. Spotted gar, therefore, serves as an appropriate outgroup, or ancestral/ancient fish, that did not undergo the teleost-specific WGD. As such, analyses of the spatio-temporal regulation of spotted gar genes provides a foundation to determine whether the duplicated fabp genes have been retained in teleost genomes owing to either sub- or neofunctionalization. Copyright © 2017 Elsevier Inc. All rights reserved.

Fish quarantine: current practices in public zoos and aquaria.

PubMed

Hadfield, Catherine A; Clayton, Leigh A

2011-12-01

The primary goal of quarantine is to reduce the risk of introducing infectious diseases into established collections. Fish quarantine is inherently complex because of the variety of species, environmental requirements, and facilities. To examine current practices, questionnaires were submitted to 60 public zoos and aquaria, predominantly in North America. Questions reviewed system type (closed, flow-through), quarantine length, diagnostics, treatments, and cleaning and disinfection. Forty-two of the 60 institutions responded. Most institutions had separate quarantine protocols for freshwater teleosts, marine teleosts, and elasmobranchs. Ninety-five percent of institutions had a minimum quarantine period of 30 days or more. Sixty-four percent of institutions used isolated areas for some or all of their fish quarantine. Twenty-five percent had designated fish quarantine staff. All institutions used regular visual examinations to assess animal health. Fifty-four percent of the institutions carried out routine hands-on diagnostics on some fish; this was more common for elasmobranchs than teleosts. All institutions carried out necropsies on mortalities. Fifteen percent of institutions performed histopathology on almost all fresh mortalities; 54% percent performed histopathology on less than 10% of mortalities. Prophylactic treatments were common in closed systems, in particular, formalin immersion for teleosts, freshwater dips and copper sulfate immersion for marine teleosts, and praziquantel immersion for marine teleosts and elasmobranchs. Institutions using dips generally did so at the start or end of quarantine. Fenbendazole- and praziquantel-medicated foods were used commonly in teleosts, but dosages varied greatly. Cleaning and disinfection of systems and equipment increased in response to known pathogens. These results can be used to compare and discuss fish quarantine practices at display facilities in order to improve quarantine success.

Comparative genomics of duplicate γ-glutamyl transferase genes in teleosts: medaka (Oryzias latipes), stickleback (Gasterosteus aculeatus), green spotted pufferfish (Tetraodon nigroviridis), fugu (Takifugu rubripes), and zebrafish (Danio rerio).

PubMed

Law, Sheran Hiu Wan; Redelings, Benjamin David; Kullman, Seth William

2012-01-15

The availability of multiple teleost (bony fish) genomes is providing unprecedented opportunities to understand the diversity and function of gene duplication events using comparative genomics. Here we examine multiple paralogous genes of γ-glutamyl transferase (GGT) in several distantly related teleost species including medaka, stickleback, green spotted pufferfish, fugu, and zebrafish. Through mining genome databases, we have identified multiple GGT orthologs. Duplicate (paralogous) GGT sequences for GGT1 (GGT1 a and b), GGTL1 (GGTL1 a and b), and GGTL3 (GGTL3 a and b) were identified for each species. Phylogenetic analysis suggests that GGTs are ancient proteins conserved across most metazoan phyla and those paralogous GGTs in teleosts likely arose from the serial 3R genome duplication events. A third GGTL1 gene (GGTL1c) was found in green spotted pufferfish; however, this gene is not present in medaka, stickleback, or fugu. Similarly, one or both paralogs of GGTL3 appear to have been lost in green spotted pufferfish, fugu, and zebrafish. Syntenic relationships were highly maintained between duplicated teleost chromosomes, among teleosts and across ray-finned (Actinopterygii) and lobe-finned (Sarcopterygii) species. To assess subfunction partitioning, six medaka GGT genes were cloned and assessed for developmental and tissue-specific expression. On the basis of these data, we propose a modification of the "duplication-degeneration-complementation" model of subfunction partitioning where quantitative differences rather than absolute differences in gene expression are observed between gene paralogs. Our results demonstrate that multiple GGT genes have been retained within teleost genomes. Questions remain, however, regarding the functional roles of multiple GGTs in these species. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.

Comprehensive analysis of MHC class II genes in teleost fish genomes reveals dispensability of the peptide-loading DM system in a large part of vertebrates

PubMed Central

2013-01-01

Background Classical major histocompatibility complex (MHC) class II molecules play an essential role in presenting peptide antigens to CD4+ T lymphocytes in the acquired immune system. The non-classical class II DM molecule, HLA-DM in the case of humans, possesses critical function in assisting the classical MHC class II molecules for proper peptide loading and is highly conserved in tetrapod species. Although the absence of DM-like genes in teleost fish has been speculated based on the results of homology searches, it has not been definitively clear whether the DM system is truly specific for tetrapods or not. To obtain a clear answer, we comprehensively searched class II genes in representative teleost fish genomes and analyzed those genes regarding the critical functional features required for the DM system. Results We discovered a novel ancient class II group (DE) in teleost fish and classified teleost fish class II genes into three major groups (DA, DB and DE). Based on several criteria, we investigated the classical/non-classical nature of various class II genes and showed that only one of three groups (DA) exhibits classical-type characteristics. Analyses of predicted class II molecules revealed that the critical tryptophan residue required for a classical class II molecule in the DM system could be found only in some non-classical but not in classical-type class II molecules of teleost fish. Conclusions Teleost fish, a major group of vertebrates, do not possess the DM system for the classical class II peptide-loading and this sophisticated system has specially evolved in the tetrapod lineage. PMID:24279922

Obtaining a more resolute teleost growth hormone phylogeny by the introduction of gaps in sequence alignment.

PubMed

Rubin, D A; Dores, R M

1995-06-01

In order to obtain a more resolute phylogeny of teleosts based on growth hormone (GH) sequences, phylogenetic analyses were performed in which deletions (gaps), which appear to be order specific, were upheld to maintain GH's structural information. Sequences were analyzed at 194 amino acid positions. In addition, the two closest genealogically related groups to the teleosts, Amia calva and Acipenser guldenstadti, were used as outgroups. Modified sequence alignments were also analyzed to determine clade stability. Analyses indicated, in the most parsimonious cladogram, that molecular and morphological relationships for the orders of fishes are congruent. With GH molecular sequence data it was possible to resolve all clades at the familial level. Analyses of the primary sequence data indicate that: (a) the halecomorphean and chondrostean GH sequences are the appropriate outgroups for generating the most parsimonious cladogram for teleosts; (b) proper alignment of teleost GH sequence by the inclusion of gaps is necessary for resolution of the Percomorpha; and (c) removal of sequence information by deleting improperly aligned sequence decreases the phylogenetic signal obtained.

Linking species habitat and past palaeoclimatic events to evolution of the teleost innate immune system.

PubMed

Solbakken, Monica Hongrø; Voje, Kjetil Lysne; Jakobsen, Kjetill Sigurd; Jentoft, Sissel

2017-04-26

Host-intrinsic factors as well as environmental changes are known to be strong evolutionary drivers defining the genetic foundation of immunity. Using a novel set of teleost genomes and a time-calibrated phylogeny, we here investigate the family of Toll-like receptor ( TLR ) genes and address the underlying evolutionary processes shaping the diversity of the first-line defence. Our findings reveal remarkable flexibility within the evolutionary design of teleost innate immunity characterized by prominent TLR gene losses and expansions. In the order of Gadiformes, expansions correlate with the loss of major histocompatibility complex class II ( MHCII ) and diversifying selection analyses support that this has fostered new immunological innovations in TLR s within this lineage. In teleosts overall, TLRs expansions correlate with species latitudinal distributions and maximum depth. By contrast, lineage-specific gene losses overlap with well-described changes in palaeoclimate (global ocean anoxia) and past Atlantic Ocean geography. In conclusion, we suggest that the evolvability of the teleost immune system has most likely played a prominent role in the survival and successful radiation of this lineage. © 2017 The Authors.

Whole genome sequencing data and de novo draft assemblies for 66 teleost species

PubMed Central

Malmstrøm, Martin; Matschiner, Michael; Tørresen, Ole K.; Jakobsen, Kjetill S.; Jentoft, Sissel

2017-01-01

Teleost fishes comprise more than half of all vertebrate species, yet genomic data are only available for 0.2% of their diversity. Here, we present whole genome sequencing data for 66 new species of teleosts, vastly expanding the availability of genomic data for this important vertebrate group. We report on de novo assemblies based on low-coverage (9–39×) sequencing and present detailed methodology for all analyses. To facilitate further utilization of this data set, we present statistical analyses of the gene space completeness and verify the expected phylogenetic position of the sequenced genomes in a large mitogenomic context. We further present a nuclear marker set used for phylogenetic inference and evaluate each gene tree in relation to the species tree to test for homogeneity in the phylogenetic signal. Collectively, these analyses illustrate the robustness of this highly diverse data set and enable extensive reuse of the selected phylogenetic markers and the genomic data in general. This data set covers all major teleost lineages and provides unprecedented opportunities for comparative studies of teleosts. PMID:28094797

A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands

PubMed Central

Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Wesselingh, Frank P.; Antoine, Pierre-Olivier

2015-01-01

Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman—Gnatusuchus pebasensis—bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. PMID:25716785

Structural and functional divergence of two fish aquaporin-1 water channels following teleost-specific gene duplication

PubMed Central

2008-01-01

Background Teleost radiation in the oceans required specific physiological adaptations in eggs and early embryos to survive in the hyper-osmotic seawater. Investigating the evolution of aquaporins (AQPs) in these vertebrates should help to elucidate how mechanisms for water homeostasis evolved. The marine teleost gilthead sea bream (Sparus aurata) has a mammalian aquaporin-1 (AQP1)-related channel, termed AQP1o, with a specialized physiological role in mediating egg hydration. However, teleosts have an additional AQP isoform structurally more similar to AQP1, though its relationship with AQP1o is unclear. Results By using phylogenetic and genomic analyses we show here that teleosts, unlike tetrapods, have two closely linked AQP1 paralogous genes, termed aqp1a and aqp1b (formerly AQP1o). In marine teleosts that produce hydrated eggs, aqp1b is highly expressed in the ovary, whereas in freshwater species that produce non-hydrated eggs, aqp1b has a completely different expression pattern or is not found in the genome. Both Aqp1a and Aqp1b are functional water-selective channels when expressed in Xenopus laevis oocytes. However, expression of chimeric and mutated proteins in oocytes revealed that the sea bream Aqp1b C-terminus, unlike that of Aqp1a, contains specific residues involved in the control of Aqp1b intracellular trafficking through phosphorylation-independent and -dependent mechanisms. Conclusion We propose that 1) Aqp1a and Aqp1b are encoded by distinct genes that probably originated specifically in the teleost lineage by duplication of a common ancestor soon after divergence from tetrapods, 2) Aqp1b possibly represents a neofunctionalized AQP adapted to oocytes of marine and catadromous teleosts, thereby contributing to a water reservoir in eggs and early embryos that increases their survival in the ocean, and 3) Aqp1b independently acquired regulatory domains in the cytoplasmatic C-terminal tail for the specific control of Aqp1b expression in the plasma membrane. PMID:18811940

Retinal projections in the bowfin, Amia calva: cytoarchitectonic and experimental analysis.

PubMed

Butler, A B; Northcutt, R G

1992-01-01

The retinofugal projections in the bowfin, a non-teleost actinopterygian, were studied by autoradiographic and horseradish peroxidase methods, and the cytoarchitecture of retinorecipient regions of the diencephalon was analyzed with serially sectioned, Bodian stained material. Nuclei were identified in the thalamus, the periventricular portion of the posterior tuberculum, synencephalon, and pretectum which are homologous to like-named nuclei in teleosts and other non-teleost actinopterygian fishes. Of particular note, a posterior pretectal nucleus and, possibly, a homologue of nucleus corticalis were found to be present in the pretectum. These nuclei have previously been identified only in teleosts. The posterior pretectal nucleus is relatively small in the bowfin, and the distribution of a small, versus a large, posterior pretectal nucleus in Teleostei and Halecomorphi suggests that this nucleus was small plesiomorphically. The pattern of retinofugal projections in the bowfin is similar to that in other non-teleost actinopterygian fishes and in teleosts in most regards. Contralaterally, the retina projects to nuclei in the dorsal and ventral thalamus, superficial and central pretectum, dorsal and ventral accessory optic nuclei, and to the optic tectum. Additionally, there are sparse projections to the suprachiasmatic nucleus in the preoptic area, the periventricular nucleus of the posterior tuberculum, and the dorsal and ventral periventricular pretectal nuclei. Ipsilateral projections are sparse and are derived from fibers which do not decussate in the optic chiasm. Undecussated ipsilateral retinal projections, as present in the bowfin, are a widely distributed character in vertebrates and appear to be plesiomorphic for vertebrates.

Nocturnality constrains morphological and functional diversity in the eyes of reef fishes.

PubMed

Schmitz, Lars; Wainwright, Peter C

2011-11-19

Ambient light levels are often considered to drive the evolution of eye form and function. Diel activity pattern is the main mechanism controlling the visual environment of teleost reef fish, with day-active (diurnal) fish active in well-illuminated conditions, whereas night-active (nocturnal) fish cope with dim light. Physiological optics predicts several specific evolutionary responses to dim-light vision that should be reflected in visual performance features of the eye. We analyzed a large comparative dataset on morphological traits of the eyes in 265 species of teleost reef fish in 43 different families. The eye morphology of nocturnal reef teleosts is characterized by a syndrome that indicates better light sensitivity, including large relative eye size, high optical ratio and large, rounded pupils. Improved dim-light image formation comes at the cost of reduced depth of focus and reduction of potential accommodative lens movement. Diurnal teleost reef fish, released from the stringent functional requirements of dim-light vision have much higher morphological and optical diversity than nocturnal species, with large ranges of optical ratio, depth of focus, and lens accommodation. Physical characteristics of the environment are an important factor in the evolution and diversification of the vertebrate eye. Both teleost reef fish and terrestrial amniotes meet the functional requirements of dim-light vision with a similar evolutionary response of morphological and optical modifications. The trade-off between improved dim-light vision and reduced optical diversity may be a key factor in explaining the lower trophic diversity of nocturnal reef teleosts.

Bathymetric limits of chondrichthyans in the deep sea: A re-evaluation

NASA Astrophysics Data System (ADS)

Musick, J. A.; Cotton, C. F.

2015-05-01

Chondrichthyans are largely absent in abyssal (>3000 m) habitats in most regions of the world ocean and are uncommon below 2000 m. The deeper-living chondrichthyans include certain rajids, squaliforms and holocephalans. Several hypotheses have been erected to explain the absence of chondrichthyans from the abyss. These are mostly based on energetics: deep-sea food webs are impoverished due to their distance from primary production, and chondrichthyans, occupying the highest trophic levels, cannot be supported due to entropy among trophic levels. We examined this hypothesis by comparing trophic levels, calculated from dietary data, of deep-sea chondrichthyans with those of deep-sea teleosts. Chondrichthyans were mostly above trophic level 4, whereas all the teleosts examined were below that level. Both small and medium squaloids, as well as sharks and skates of large size, feed on fishes, cephalopods and scavenged prey, and thus occupy the highest trophic levels in bathydemersal fish communities. In addition, whereas teleosts and chondrichthyans both store lipids in their livers to support long periods of fasting, chondrichthyans must devote much of their liver lipids to maintain neutral buoyancy. Consequently teleosts with swim bladders are better adapted to survive in the abyss where food sources are sparse and unpredictable. The potential prey field for both chondrichthyans and teleosts declines in biomass and diversity with depth, but teleosts have more flexibility in their feeding mechanisms and food habits, and occupy abyssal trophic guilds for which chondrichthyans are ill adapted.

Resurfacing history of the northern plains of Mars based on geologic mapping of Mars Global Surveyor data

USGS Publications Warehouse

Tanaka, K.L.; Skinner, J.A.; Hare, T.M.; Joyal, T.; Wenker, A.

2003-01-01

Geologic mapping of the northern plains of Mars, based on Mars Orbiter Laser Altimeter topography and Viking and Mars Orbiter Camera images, reveals new insights into geologic processes and events in this region during the Hesperian and Amazonian Periods. We propose four successive stages of lowland resurfacing likely related to the activity of near-surface volatiles commencing at the highland-lowland boundary (HLB) and progressing to lower topographic levels as follows (highest elevations indicated): Stage 1, upper boundary plains, Early Hesperian, <-2.0 to -2.9 km; Stage 2, lower boundary plains and outflow channel dissection, Late Hesperian, <-2.7 to -4.0 km; Stage 3, Vastitas Borealis Formation (VBF) surface, Late Hesperian to Early Amazonian, <-3.1 to -4.1 km; and Stage 4, local chaos zones, Early Amazonian, <-3.8 to -5.0 km. At Acidalia Mensa, Stage 2 and 3 levels may be lower (<-4.4 and -4.8 km, respectively). Contractional ridges form the dominant structure in the plains and developed from near the end of the Early Hesperian to the Early Amazonian. Geomorphic evidence for a northern-plains-filling ocean during Stage 2 is absent because one did not form or its evidence was destroyed by Stage 3 resurfacing. Remnants of possible Amazonian dust mantles occur on top of the VBF. The north polar layered deposits appear to be made up of an up to kilometer-thick lower sequence of sandy layers Early to Middle Amazonian in age overlain by Late Amazonian ice-rich dust layers; both units appear to have outliers, suggesting that they once were more extensive.

A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands.

PubMed

Salas-Gismondi, Rodolfo; Flynn, John J; Baby, Patrice; Tejada-Lara, Julia V; Wesselingh, Frank P; Antoine, Pierre-Olivier

2015-04-07

Amazonia contains one of the world's richest biotas, but origins of this diversity remain obscure. Onset of the Amazon River drainage at approximately 10.5 Ma represented a major shift in Neotropical ecosystems, and proto-Amazonian biotas just prior to this pivotal episode are integral to understanding origins of Amazonian biodiversity, yet vertebrate fossil evidence is extraordinarily rare. Two new species-rich bonebeds from late Middle Miocene proto-Amazonian deposits of northeastern Peru document the same hyperdiverse assemblage of seven co-occurring crocodylian species. Besides the large-bodied Purussaurus and Mourasuchus, all other crocodylians are new taxa, including a stem caiman-Gnatusuchus pebasensis-bearing a massive shovel-shaped mandible, procumbent anterior and globular posterior teeth, and a mammal-like diastema. This unusual species is an extreme exemplar of a radiation of small caimans with crushing dentitions recording peculiar feeding strategies correlated with a peak in proto-Amazonian molluscan diversity and abundance. These faunas evolved within dysoxic marshes and swamps of the long-lived Pebas Mega-Wetland System and declined with inception of the transcontinental Amazon drainage, favouring diversification of longirostrine crocodylians and more modern generalist-feeding caimans. The rise and demise of distinctive, highly productive aquatic ecosystems substantially influenced evolution of Amazonian biodiversity hotspots of crocodylians and other organisms throughout the Neogene. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

The hypothalamus–pituitary–thyroid axis in teleosts and amphibians: Endocrine disruption and its consequences to natural populations

USGS Publications Warehouse

Carr, J.A.; Patino, Reynaldo

2011-01-01

Teleosts and pond-breeding amphibians may be exposed to a wide variety of anthropogenic, waterborne contaminants that affect the hypothalamus-pituitary-thyroid (HPT) axis. Because thyroid hormone is required for their normal development and reproduction, the potential impact of HPT-disrupting contaminants on natural teleost and amphibian populations raises special concern. There is laboratory evidence indicating that persistent organic pollutants, heavy metals, pharmaceutical and personal care products, agricultural chemicals, and aerospace products may alter HPT activity, development, and reproduction in teleosts and amphibians. However, at present there is no evidence to clearly link contaminant-induced HPT alterations to impairments in teleost or amphibian population health in the field. Also, with the exception of perchlorate for which laboratory studies have shown a direct link between HPT disruption and adverse impacts on development and reproductive physiology, little is known about if or how other HPT-disrupting contaminants affect organismal performance. Future field studies should focus on establishing temporal associations between the presence of HPT-disrupting chemicals, the occurrence of HPT alterations, and adverse effects on development and reproduction in natural populations; as well as determining how complex mixtures of HPT contaminants affect organismal and population health.

The hypothalamus-pituitary-thyroid axis in teleosts and amphibians: Endocrine disruption and its consequences to natural populations

USGS Publications Warehouse

Carr, J.A.; Patino, R.

2011-01-01

Teleosts and pond-breeding amphibians may be exposed to a wide variety of anthropogenic, waterborne contaminants that affect the hypothalamus-pituitary-thyroid (HPT) axis. Because thyroid hormone is required for their normal development and reproduction, the potential impact of HPT-disrupting contaminants on natural teleost and amphibian populations raises special concern. There is laboratory evidence indicating that persistent organic pollutants, heavy metals, pharmaceutical and personal care products, agricultural chemicals, and aerospace products may alter HPT activity, development, and reproduction in teleosts and amphibians. However, at present there is no evidence to clearly link contaminant-induced HPT alterations to impairments in teleost or amphibian population health in the field. Also, with the exception of perchlorate for which laboratory studies have shown a direct link between HPT disruption and adverse impacts on development and reproductive physiology, little is known about if or how other HPT-disrupting contaminants affect organismal performance. Future field studies should focus on establishing temporal associations between the presence of HPT-disrupting chemicals, the occurrence of HPT alterations, and adverse effects on development and reproduction in natural populations; as well as determining how complex mixtures of HPT contaminants affect organismal and population health. ?? 2010 Elsevier Inc.

Nocturnality constrains morphological and functional diversity in the eyes of reef fishes

PubMed Central

2011-01-01

Background Ambient light levels are often considered to drive the evolution of eye form and function. Diel activity pattern is the main mechanism controlling the visual environment of teleost reef fish, with day-active (diurnal) fish active in well-illuminated conditions, whereas night-active (nocturnal) fish cope with dim light. Physiological optics predicts several specific evolutionary responses to dim-light vision that should be reflected in visual performance features of the eye. Results We analyzed a large comparative dataset on morphological traits of the eyes in 265 species of teleost reef fish in 43 different families. The eye morphology of nocturnal reef teleosts is characterized by a syndrome that indicates better light sensitivity, including large relative eye size, high optical ratio and large, rounded pupils. Improved dim-light image formation comes at the cost of reduced depth of focus and reduction of potential accommodative lens movement. Diurnal teleost reef fish, released from the stringent functional requirements of dim-light vision have much higher morphological and optical diversity than nocturnal species, with large ranges of optical ratio, depth of focus, and lens accommodation. Conclusions Physical characteristics of the environment are an important factor in the evolution and diversification of the vertebrate eye. Both teleost reef fish and terrestrial amniotes meet the functional requirements of dim-light vision with a similar evolutionary response of morphological and optical modifications. The trade-off between improved dim-light vision and reduced optical diversity may be a key factor in explaining the lower trophic diversity of nocturnal reef teleosts. PMID:22098687

Genome Evolution and Meiotic Maps by Massively Parallel DNA Sequencing: Spotted Gar, an Outgroup for the Teleost Genome Duplication

PubMed Central

Amores, Angel; Catchen, Julian; Ferrara, Allyse; Fontenot, Quenton; Postlethwait, John H.

2011-01-01

Genomic resources for hundreds of species of evolutionary, agricultural, economic, and medical importance are unavailable due to the expense of well-assembled genome sequences and difficulties with multigenerational studies. Teleost fish provide many models for human disease but possess anciently duplicated genomes that sometimes obfuscate connectivity. Genomic information representing a fish lineage that diverged before the teleost genome duplication (TGD) would provide an outgroup for exploring the mechanisms of evolution after whole-genome duplication. We exploited massively parallel DNA sequencing to develop meiotic maps with thrift and speed by genotyping F1 offspring of a single female and a single male spotted gar (Lepisosteus oculatus) collected directly from nature utilizing only polymorphisms existing in these two wild individuals. Using Stacks, software that automates the calling of genotypes from polymorphisms assayed by Illumina sequencing, we constructed a map containing 8406 markers. RNA-seq on two map-cross larvae provided a reference transcriptome that identified nearly 1000 mapped protein-coding markers and allowed genome-wide analysis of conserved synteny. Results showed that the gar lineage diverged from teleosts before the TGD and its genome is organized more similarly to that of humans than teleosts. Thus, spotted gar provides a critical link between medical models in teleost fish, to which gar is biologically similar, and humans, to which gar is genomically similar. Application of our F1 dense mapping strategy to species with no prior genome information promises to facilitate comparative genomics and provide a scaffold for ordering the numerous contigs arising from next generation genome sequencing. PMID:21828280

New Brazilian Cerambycidae from the Amazonian region (Coleoptera).

PubMed

Santos-Silva, Antonio; Galileo, Maria Helena M

2016-01-01

Three new species of Cerambycidae are described from the Brazilian Amazonian region: Psapharochrus bezarki (Lamiinae, Acanthoderini); Xenofrea ayri (Lamiinae, Xenofreini); and Mecometopus wappesi (Cerambycinae, Clytini). Mecometopus wappesi is added to a previous key.

Hunting in the Rainforest and Mayaro Virus Infection: An emerging Alphavirus in Ecuador.

PubMed

Izurieta, Ricardo O; Macaluso, Maurizio; Watts, Douglas M; Tesh, Robert B; Guerra, Bolivar; Cruz, Ligia M; Galwankar, Sagar; Vermund, Sten H

2011-10-01

The objectives of this report were to document the potential presence of Mayaro virus infection in Ecuador and to examine potential risk factors for Mayaro virus infection among the personnel of a military garrison in the Amazonian rainforest. The study population consisted of the personnel of a garrison located in the Ecuadorian Amazonian rainforest. The cross-sectional study employed interviews and seroepidemiological methods. Humoral immune response to Mayaro virus infection was assessed by evaluating IgM- and IgG-specific antibodies using ELISA. Of 338 subjects studied, 174 were from the Coastal zone of Ecuador, 73 from Andean zone, and 91 were native to the Amazonian rainforest. Seroprevalence of Mayaro virus infection was more than 20 times higher among Amazonian natives (46%) than among subjects born in other areas (2%). Age and hunting in the rainforest were significant predictors of Mayaro virus infection overall and among Amazonian natives. The results provide the first demonstration of the potential presence of Mayaro virus infection in Ecuador and a systematic evaluation of risk factors for the transmission of this alphavirus. The large difference in prevalence rates between Amazonian natives and other groups and between older and younger natives suggest that Mayaro virus is endemic and enzootic in the rainforest, with sporadic outbreaks that determine differences in risk between birth cohorts of natives. Deep forest hunting may selectively expose native men, descendants of the Shuar and Huaronai ethnic groups, to the arthropod vectors of Mayaro virus in areas close to primate reservoirs.

Chloride inhibition of nitrite uptake for non-teleost Actinopterygiian fishes.

PubMed

Boudreaux, Perry J; Ferrara, Allyse M; Fontenot, Quenton C

2007-06-01

Fish that transport environmental chloride with a gill uptake mechanism (gill epithelial Cl(-)/HCO(3)(-)cotransport exchange system), also transport nitrite into plasma through the same mechanism. Because of the relationship between nitrite uptake and the gill chloride uptake mechanism, nitrite uptake can provide insight regarding the method of chloride uptake for fish. This study was designed to determine if non-teleost fishes concentrate nitrite in their plasma, and to determine if chloride inhibits nitrite uptake in non-teleost fish. To determine if bowfin Amia calva, spotted gar Lepisosteus oculatus, alligator gar Atractosteus spatula, and paddlefish Polyodon spathula concentrate environmental nitrite in their plasma, individuals were exposed to concentrations of 0, 1, 10, or 100 mg/L nitrite-N. After exposure, all species had plasma nitrite-N concentrations greater than environmental levels. To determine if chloride inhibits nitrite uptake for spotted gar, alligator gar, and paddlefish, fish were exposed to 1 mg/L nitrite-N and 20 mg/L chloride as calcium chloride, or to 1 mg/L nitrite-N only. Chloride effectively prevented nitrite from being concentrated in the plasma of all species. It appears that non-teleost fish concentrate nitrite in their plasma via their chloride uptake mechanism and that this is an ancestral characteristic for teleost.

Recent findings on the structure and function of teleost IgT

PubMed Central

Zhang, Yong-An; Salinas, Irene; Sunyer, J. Oriol

2011-01-01

As key effector molecules of jawed vertebrate’s adaptive immune system, immunoglobulins are produced by B lymphocytes, either as a secretory form (antibody) or as a membrane form (B cell receptor). Until recently, teleost fish B cells were thought to express only two classes of immunoglobulins, IgM and IgD. In addition, IgM in these species was thought to be the only immunoglobulin isotype responding to pathogens both in systemic or mucosal compartments. However, the unexpected discovery of IgT, a new teleost immunoglobulin unearthed in 2005, has provided for new opportunities to analyze further roles of teleost immunoglobulins in these two physiologically distinct compartments. The smoke about the potential function of IgT has cleared recently with the finding that this immunoglobulin appears to be specialized in gut mucosal immunity. Significantly, the new capability of measuring not only IgM but also IgT responses will greatly facilitate the evaluation and understanding of fish immune responses as well as the protective effects of fish vaccines. The purpose of this review is to summarize the molecular characterization of new IgT orthologs and subtypes in teleosts, as well as to describe the new findings concerning the protein structure of IgT, the B cells producing it, and its role in mucosal immunity. PMID:21466854

Observations On Some Upper Amazonian Wetlands of Southeastern Peru

NASA Astrophysics Data System (ADS)

Householder, J. E.; Muttiah, R.; Khanal, S.

2007-05-01

Upper Amazonian wetlands represent little studied, poorly understood, and grossly under protected systems. Scientific investigation of Amazonian wetlands is in its infancy; nor is there much known about their ecological services. Regionally, wetlands form a ubiquitous and significant component of floodplain habitat fed by perennial springs as well as overland runoff. Locally, wetland vegetation forms bewilderingly complex vegetation mosaics that seem to be governed by local topography and hydrology. Drawing upon intensive field campaigns and remotely sensed imagery, we summarize the results and experiences gathered in wetlands of southeastern Peru.

Potential mechanisms of influence of the Leeuwin Current eddy system on teleost recruitment to the Western Australian continental shelf

NASA Astrophysics Data System (ADS)

Gaughan, Daniel J.

2007-04-01

The Leeuwin Current (LC), an oligotrophic, warm current that flows south (poleward) along the shelf-break off the west coast of Australia and then east along the south coast, is recognized as a key factor affecting fisheries production in the region, but the mechanisms for this influence have not been determined. Recruitment strength of the globally significant western rock lobster ( Panulirus cygnus) stock is correlated to interannual variations in the strength of the LC. While this relationship has been based on a 2-decade time-series of P. cygnus recruitment data, the important teleost species of the region rarely have recruitment data for more than a few years; yet this group is nonetheless economically, socially and politically important. Furthermore, there is little knowledge of the egg- and larval-stage dynamics for the majority of these teleosts. Previous and new information on those aspects of the LC system that could theoretically impact on recruitment of shelf teleosts were identified to provide a basis for developing a conceptual model of how the LC could affect recruitment. The potential impacts of the LC system, which entrains shelf water, were examined with reference to retention/loss of teleost eggs and larvae and positive/negative influences on feeding conditions for larvae. Owing to the lack of early-life-history information for many teleosts in Western Australia, this was undertaken for generalized shelf species whose eggs are spawned on the shelf and whose larvae must settle on the shelf to access favourable nursery habitat. The results indicate that the LC system most likely contributes a net negative impact on success of teleost eggs and larvae. Larvae of shelf teleosts entrained and trapped in the warm-core (WC) eddies that form from the LC and then propagate offshore would contribute little to recruitment. Given that larval teleosts predominantly feed on copepods and that these were much less abundant in the WC eddy than is typical of shelf waters, the general larval feeding conditions in the WC eddy were inferior to those on the shelf. Any larvae that escaped from the eddy that were able to orientate towards the shelf and had sustained swimming capabilities would incur significant energetic penalties when attempting to return to the shelf. Furthermore, flow of the LC onto the shelf could dilute the concentrations of phytoplankton and zooplankton, negatively impacting feeding conditions for larvae that remain on the shelf. Clarification of the timing and geographical locations of interactions between the LC and shelf waters relative to spawning behaviour of shelf teleosts is required before the potential negative impacts on recruitment can be adequately quantified. However, because fisheries management issues cannot (always) await detailed understanding of biophysical effects on recruitment, the conceptual model of potential effects was developed here to provide immediate improvements for interpretation of stock assessment information, for which recruitment variability is often a key uncertainty. Finally, an improved understanding of the effects of mesoscale oceanography on fish stocks will increase the ability for fisheries managers to discuss climate-change implications with stakeholders.

Oocyte quality of tambaqui (Colossoma macropomum) during the reproductive season.

PubMed

Galo, J M; Ribeiro, R P; Streit-Junior, D P; Albuquerque, D M; Fornari, D C; Roma, C F C; Guerreiro, L R J

2015-05-01

The study aimed to analyze the Colossoma macropomum reproductive behavior and quality of the female gametes throughout the reproductive season. The experiment was carried out in Pimenta Bueno - Rondônia State (Northern Brazil) during the reproductive season (2010-2011) using 36 females. Each sampling was performed on a 15 ± 5 days interval. Female gametes were collected by stripping and the following analyses were performed: weight of oocytes released (g); productivity index, fertilization and hatching rate. During the sampling period was verified effect (p < 0.05) of collecting time into the season for oocytes weight, productivity index and fertilization rate. Although the period 3 (December) did not differ significantly from other periods, it showed better parameters for the quality of C. macropomum oocytes.

New Brazilian Cerambycidae from the Amazonian region (Coleoptera)

PubMed Central

Santos-Silva, Antonio; Galileo, Maria Helena M.

2016-01-01

Abstract Three new species of Cerambycidae are described from the Brazilian Amazonian region: Psapharochrus bezarki (Lamiinae, Acanthoderini); Xenofrea ayri (Lamiinae, Xenofreini); and Mecometopus wappesi (Cerambycinae, Clytini). Mecometopus wappesi is added to a previous key. PMID:27551200

Conserved structure and expression of hsp70 paralogs in teleost fishes.

PubMed

Metzger, David C H; Hemmer-Hansen, Jakob; Schulte, Patricia M

2016-06-01

The cytosolic 70KDa heat shock proteins (Hsp70s) are widely used as biomarkers of environmental stress in ecological and toxicological studies in fish. Here we analyze teleost genome sequences to show that two genes encoding inducible hsp70s (hsp70-1 and hsp70-2) are likely present in all teleost fish. Phylogenetic and synteny analyses indicate that hsp70-1 and hsp70-2 are distinct paralogs that originated prior to the diversification of the teleosts. The promoters of both genes contain a TATA box and conserved heat shock elements (HSEs), but unlike mammalian HSP70s, both genes contain an intron in the 5' UTR. The hsp70-2 gene has undergone tandem duplication in several species. In addition, many other teleost genome assemblies have multiple copies of hsp70-2 present on separate, small, genomic scaffolds. To verify that these represent poorly assembled tandem duplicates, we cloned the genomic region surrounding hsp70-2 in Fundulus heteroclitus and showed that the hsp70-2 gene copies that are on separate scaffolds in the genome assembly are arranged as tandem duplicates. Real-time quantitative PCR of F. heteroclitus genomic DNA indicates that four copies of the hsp70-2 gene are likely present in the F. heteroclitus genome. Comparison of expression patterns in F. heteroclitus and Gasterosteus aculeatus demonstrates that hsp70-2 has a higher fold increase than hsp70-1 following heat shock in gill but not in muscle tissue, revealing a conserved difference in expression patterns between isoforms and tissues. These data indicate that ecological and toxicological studies using hsp70 as a biomarker in teleosts should take this complexity into account. Copyright © 2016 Elsevier Inc. All rights reserved.

Evolutionary history of the ABCB2 genomic region in teleosts

USGS Publications Warehouse

Palti, Y.; Rodriguez, M.F.; Gahr, S.A.; Hansen, J.D.

2007-01-01

Gene duplication, silencing and translocation have all been implicated in shaping the unique genomic architecture of the teleost MH regions. Previously, we demonstrated that trout possess five unlinked regions encoding MH genes. One of these regions harbors ABCB2 which in all other vertebrate classes is found in the MHC class II region. In this study, we sequenced a BAC contig for the trout ABCB2 region. Analysis of this region revealed the presence of genes homologous to those located in the human class II (ABCB2, BRD2, ??DAA), extended class II (RGL2, PHF1, SYGP1) and class III (PBX2, Notch-L) regions. The organization and syntenic relationships of this region were then compared to similar regions in humans, Tetraodon and zebrafish to learn more about the evolutionary history of this region. Our analysis indicates that this region was generated during the teleost-specific duplication event while also providing insight about potential MH paralogous regions in teleosts. ?? 2006 Elsevier Ltd. All rights reserved.

MicroRNA in Teleost Fish

PubMed Central

Bizuayehu, Teshome Tilahun; Babiak, Igor

2014-01-01

MicroRNAs (miRNAs) are transcriptional and posttranscriptional regulators involved in nearly all known biological processes in distant eukaryotic clades. Their discovery and functional characterization have broadened our understanding of biological regulatory mechanisms in animals and plants. They show both evolutionary conserved and unique features across Metazoa. Here, we present the current status of the knowledge about the role of miRNA in development, growth, and physiology of teleost fishes, in comparison to other vertebrates. Infraclass Teleostei is the most abundant group among vertebrate lineage. Fish are an important component of aquatic ecosystems and human life, being the prolific source of animal proteins worldwide and a vertebrate model for biomedical research. We review miRNA biogenesis, regulation, modifications, and mechanisms of action. Specific sections are devoted to the role of miRNA in teleost development, organogenesis, tissue differentiation, growth, regeneration, reproduction, endocrine system, and responses to environmental stimuli. Each section discusses gaps in the current knowledge and pinpoints the future directions of research on miRNA in teleosts. PMID:25053657

Exploring eco-hydrological consequences of the Amazonian ecosystems under climate and land-use changes in the 21st century

NASA Astrophysics Data System (ADS)

Zhang, K.; Castanho, A. D.; Moghim, S.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Levine, N. M.; Longo, M.; McKnight, S.; Wang, J.; Moorcroft, P. R.

2012-12-01

Deforestation and drought have imposed regional-scale perturbations onto Amazonian ecosystems and are predicted to cause larger negative impacts on the Amazonian ecosystems and associated regional carbon dynamics in the 21st century. However, global climate models (GCMs) vary greatly in their projections of future climate change in Amazonia, giving rise to uncertainty in the expected fate of the Amazon over the coming century. In this study, we explore the possible eco-hydrological consequences of the Amazonian ecosystems under projected climate and land-use changes in the 21st century using two state-of-the-art terrestrial ecosystem models—Ecosystem Demography Model 2.1(ED2.1) and Integrated Biosphere Simulator model (IBIS)—driven by three representative, bias-corrected climate projections from three IPCC GCMs (NCARPCM1, NCARCCSM3 and HadCM3), coupled with two land-use change scenarios (a business-as-usual and a strict governance scenario). We also analyze the relative roles of climate change, CO2 fertilization, land-use change and fire in driving the projected composition and structure of the Amazonian ecosystems. Our results show that CO2 fertilization enhances vegetation productivity and above-ground biomass (AGB) in the region, while land-use change and fire cause AGB loss and the replacement of forests by the savanna-like vegetation. The impacts of climate change depend strongly on the direction and severity of projected precipitation changes in the region. In particular, when intensified water stress is superimposed on unregulated deforestation, both ecosystem models predict large-scale dieback of Amazonian rainforests.

Tracing an invasion: landbridges, refugia, and the phylogeography of the Neotropical rattlesnake (Serpentes: Viperidae: Crotalus durissus).

PubMed

Wüster, Wolfgang; Ferguson, Julia E; Quijada-Mascareñas, J Adrian; Pook, Catharine E; Salomão, Maria da Graça; Thorpe, Roger S

2005-04-01

Abstract Pleistocene fragmentation of the Amazonian rainforest has been hypothesized to be a major cause of Neotropical speciation and diversity. However, the role and even the reality of Pleistocene forest refugia have attracted much scepticism. In Amazonia, previous phylogeographical studies have focused mostly on organisms found in the forests themselves, and generally found speciation events to have predated the Pleistocene. However, molecular studies of open-formation taxa found both north and south of the Amazonian forests, probably because of vicariance resulting from expansion of the rainforests, may provide novel insights into the age of continuous forest cover across the Amazon basin. Here, we analyse three mitochondrial genes to infer the phylogeography of one such trans-Amazonian vicariant, the Neotropical rattlesnake (Crotalus durissus), which occupies primarily seasonal formations from Mexico to Argentina, but avoids the rainforests of Central and tropical South America. The phylogeographical pattern is consistent with gradual dispersal along the Central American Isthmus, followed by more rapid dispersal into and across South America after the uplift of the Isthmus of Panama. Low sequence divergence between populations from north and south of the Amazon rainforest is consistent with mid-Pleistocene divergence, approximately 1.1 million years ago (Ma). This suggests that the Amazonian rainforests must have become fragmented or at least shrunk considerably during that period, lending support to the Pleistocene refugia theory as an important cause of distribution patterns, if not necessarily speciation, in Amazonian forest organisms. These results highlight the potential of nonforest species to contribute to an understanding of the history of the Amazonian rainforests themselves.

Hunting in the Rainforest and Mayaro Virus Infection: An emerging Alphavirus in Ecuador

PubMed Central

Izurieta, Ricardo O; Macaluso, Maurizio; Watts, Douglas M; Tesh, Robert B; Guerra, Bolivar; Cruz, Ligia M; Galwankar, Sagar; Vermund, Sten H

2011-01-01

Objectives: The objectives of this report were to document the potential presence of Mayaro virus infection in Ecuador and to examine potential risk factors for Mayaro virus infection among the personnel of a military garrison in the Amazonian rainforest. Materials and Methods: The study population consisted of the personnel of a garrison located in the Ecuadorian Amazonian rainforest. The cross-sectional study employed interviews and seroepidemiological methods. Humoral immune response to Mayaro virus infection was assessed by evaluating IgM- and IgG-specific antibodies using ELISA. Results: Of 338 subjects studied, 174 were from the Coastal zone of Ecuador, 73 from Andean zone, and 91 were native to the Amazonian rainforest. Seroprevalence of Mayaro virus infection was more than 20 times higher among Amazonian natives (46%) than among subjects born in other areas (2%). Conclusions: Age and hunting in the rainforest were significant predictors of Mayaro virus infection overall and among Amazonian natives. The results provide the first demonstration of the potential presence of Mayaro virus infection in Ecuador and a systematic evaluation of risk factors for the transmission of this alphavirus. The large difference in prevalence rates between Amazonian natives and other groups and between older and younger natives suggest that Mayaro virus is endemic and enzootic in the rainforest, with sporadic outbreaks that determine differences in risk between birth cohorts of natives. Deep forest hunting may selectively expose native men, descendants of the Shuar and Huaronai ethnic groups, to the arthropod vectors of Mayaro virus in areas close to primate reservoirs. PMID:22223990

A Bilingual Experiment in the Amazonian Jungle of Peru

ERIC Educational Resources Information Center

Wise, Mary Ruth

1971-01-01

In the Amazonian jungle of Peru 240 Indian leaders representing 20 different South American Indian language groups are successfully teaching their own people to read and write, first in their mother tongue and then in Spanish. (Author/EB)

Evolution history of duplicated smad3 genes in teleost: insights from Japanese flounder, Paralichthys olivaceus

PubMed Central

Du, Xinxin; Liu, Yuezhong; Liu, Jinxiang; Zhang, Quanqi

2016-01-01

Following the two rounds of whole-genome duplication (WGD) during deuterosome evolution, a third genome duplication occurred in the ray-fined fish lineage and is considered to be responsible for the teleost-specific lineage diversification and regulation mechanisms. As a receptor-regulated SMAD (R-SMAD), the function of SMAD3 was widely studied in mammals. However, limited information of its role or putative paralogs is available in ray-finned fishes. In this study, two SMAD3 paralogs were first identified in the transcriptome and genome of Japanese flounder (Paralichthys olivaceus). We also explored SMAD3 duplication in other selected species. Following identification, genomic structure, phylogenetic reconstruction, and synteny analyses performed by MrBayes and online bioinformatic tools confirmed that smad3a/3b most likely originated from the teleost-specific WGD. Additionally, selection pressure analysis and expression pattern of the two genes performed by PAML and quantitative real-time PCR (qRT-PCR) revealed evidence of subfunctionalization of the two SMAD3 paralogs in teleost. Our results indicate that two SMAD3 genes originate from teleost-specific WGD, remain transcriptionally active, and may have likely undergone subfunctionalization. This study provides novel insights to the evolution fates of smad3a/3b and draws attentions to future function analysis of SMAD3 gene family. PMID:27703851

A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years

PubMed Central

Ribas, Camila C.; Aleixo, Alexandre; Nogueira, Afonso C. R.; Miyaki, Cristina Y.; Cracraft, Joel

2012-01-01

Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia. PMID:21795268

Widespread loess-like deposit in the Martian northern lowlands identifies Middle Amazonian climate change

USGS Publications Warehouse

Skinner, James A.; Tanaka, Kenneth L.; Platz, Thomas

2014-01-01

Consistently mappable units critical to distinguishing the style and interplay of geologic processes through time are sparse in the Martian lowlands. This study identifies a previously unmapped Middle Amazonian (ca. 1 Ga) unit (Middle Amazonian lowland unit, mAl) that postdates the Late Hesperian and Early Amazonian lowland plains by >2 b.y. The unit is regionally defined by subtle marginal scarps and slopes, has a mean thickness of 32 m, and extends >3.1 × 106 km2 between lat 35°N and 80°N. Pedestal-type craterforms and nested, arcuate ridges (thumbprint terrain) tend to occur adjacent to unit mAl outcrops, suggesting that current outcrops are vestiges of a more extensive deposit that previously covered ∼16 × 106 km2. Exposed layers, surface pits, and the draping of subjacent landforms allude to a sedimentary origin, perhaps as a loess-like deposit emplaced rhythmically through atmospheric fallout. We propose that unit mAl accumulated coevally with, and at the expense of, the erosion of the north polar basal units, identifying a major episode of Middle Amazonian climate-driven sedimentation in the lowlands. This work links ancient sedimentary processes to climate change that occurred well before those implied by current orbital and spin axis models.

Heterogeneous effects of market integration on sub-adult body size and nutritional status among the Shuar of Amazonian Ecuador.

PubMed

Urlacher, Samuel S; Liebert, Melissa A; Josh Snodgrass, J; Blackwell, Aaron D; Cepon-Robins, Tara J; Gildner, Theresa E; Madimenos, Felicia C; Amir, Dorsa; Bribiescas, Richard G; Sugiyama, Lawrence S

2016-07-01

Market integration (MI)-increasing production for and consumption from a market-based economy-is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. This study examines the impact of MI on sub-adult body size and nutritional status at the population, regional and household levels among the Shuar of Amazonian Ecuador. Anthropometric data were collected between 2005-2014 from 2164 Shuar (aged 2-19 years) living in two geographic regions differing in general degree of MI. High-resolution household economic, lifestyle and dietary data were collected from a sub-sample of 631 participants. Analyses were performed to investigate relationships between body size and year of data collection, region and specific aspects of household MI. Results from temporal and regional analyses suggest that MI has a significant and overall positive impact on Shuar body size and nutritional status. However, household-level results exhibit nuanced and heterogeneous specific effects of MI underlying these overarching relationships. This study provides novel insight into the complex socio-ecological pathways linking MI, physical growth and health among the Shuar and other indigenous Amazonian populations.

Heterogeneous effects of market integration on subadult body size and nutritional status among the Shuar of Amazonian Ecuador

PubMed Central

Urlacher, Samuel S.; Liebert, Melissa A.; Snodgrass, J. Josh; Blackwell, Aaron D.; Cepon-Robins, Tara J.; Gildner, Theresa E.; Madimenos, Felicia C.; Amir, Dorsa; Bribiescas, Richard G.; Sugiyama, Lawrence S.

2016-01-01

Background Market integration (MI) – increasing production for and consumption from a market-based economy – is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. Aim This study examines the impact of MI on subadult body size and nutritional status at the population, regional, and household levels among the Shuar of Amazonian Ecuador. Subjects and Methods Anthropometric data were collected between 2005 and 2014 from 2,164 Shuar (age 2-19 years) living in two geographic regions differing in general degree of MI. High-resolution household economic, lifestyle, and dietary data were collected from a subsample of 631 participants. Analyses were performed to investigate relationships between body size and year of data collection, region, and specific aspects of household MI. Results Results from temporal and regional analyses suggest that MI has a significant and overall positive impact on Shuar body size and nutritional status. However, household-level results exhibit nuanced and heterogeneous specific effects of MI underlying these overarching relationships. Conclusion This study provides novel insight into the complex socio-ecological pathways linking MI, physical growth, and health among the Shuar and other indigenous Amazonian populations. PMID:27230632

Vertebrate Osmoregulation: A Student Laboratory Exercise Using Teleost Fish

ERIC Educational Resources Information Center

Boily P.; Rees, B. B.; Williamson, L. A. C.

2007-01-01

Here, we describe a laboratory experiment as part of an upper-level vertebrate physiology course for biology majors to investigate the physiological response of vertebrates to osmoregulatory challenges. The experiment involves measuring plasma osmolality and Na[superscript +] -K[superscript +] -ATPase activity in gill tissue of teleost fish…

Mercury exposure in a high fish eating Bolivian Amazonian population with intense small-scale gold-mining activities.

PubMed

Barbieri, Flavia Laura; Cournil, Amandine; Gardon, Jacques

2009-08-01

Methylmercury exposure in Amazonian communities through fish consumption has been widely documented in Brazil. There is still a lack of data in other Amazonian countries, which is why we conducted this study in the Bolivian Amazon basin. Simple random sampling was used from a small village located in the lower Beni River, where there is intense gold mining and high fish consumption. All participants were interviewed and hair samples were taken to measure total mercury concentrations. The hair mercury geometric mean in the general population was 3.02 microg/g (CI: 2.69-3.37; range: 0.42-15.65). Age and gender were not directly associated with mercury levels. Fish consumption showed a positive relation and so did occupation, especially small-scale gold mining. Hair mercury levels were lower than those found in Brazilian studies, but still higher than in non-exposed populations. It is necessary to assess mercury exposure in the Amazonian regions where data is still lacking, using a standardized indicator.

Estimating the global conservation status of more than 15,000 Amazonian tree species.

PubMed

Ter Steege, Hans; Pitman, Nigel C A; Killeen, Timothy J; Laurance, William F; Peres, Carlos A; Guevara, Juan Ernesto; Salomão, Rafael P; Castilho, Carolina V; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E; Phillips, Oliver L; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R; Honorio Coronado, Euridice N; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G W; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F; Mogollón, Hugo F; Piedade, Maria Teresa Fernandez; Aymard C, Gerardo A; Comiskey, James A; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W; Jimenez, Eliana M; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R; Silva, Natalino; Vela, César I A; Vos, Vincent A; Zent, Eglée L; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H; Gamarra, Luis Valenzuela

2015-11-01

Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world's >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century.

Estimating the global conservation status of more than 15,000 Amazonian tree species

PubMed Central

ter Steege, Hans; Pitman, Nigel C. A.; Killeen, Timothy J.; Laurance, William F.; Peres, Carlos A.; Guevara, Juan Ernesto; Salomão, Rafael P.; Castilho, Carolina V.; Amaral, Iêda Leão; de Almeida Matos, Francisca Dionízia; de Souza Coelho, Luiz; Magnusson, William E.; Phillips, Oliver L.; de Andrade Lima Filho, Diogenes; de Jesus Veiga Carim, Marcelo; Irume, Mariana Victória; Martins, Maria Pires; Molino, Jean-François; Sabatier, Daniel; Wittmann, Florian; López, Dairon Cárdenas; da Silva Guimarães, José Renan; Mendoza, Abel Monteagudo; Vargas, Percy Núñez; Manzatto, Angelo Gilberto; Reis, Neidiane Farias Costa; Terborgh, John; Casula, Katia Regina; Montero, Juan Carlos; Feldpausch, Ted R.; Honorio Coronado, Euridice N.; Montoya, Alvaro Javier Duque; Zartman, Charles Eugene; Mostacedo, Bonifacio; Vasquez, Rodolfo; Assis, Rafael L.; Medeiros, Marcelo Brilhante; Simon, Marcelo Fragomeni; Andrade, Ana; Camargo, José Luís; Laurance, Susan G. W.; Nascimento, Henrique Eduardo Mendonça; Marimon, Beatriz S.; Marimon, Ben-Hur; Costa, Flávia; Targhetta, Natalia; Vieira, Ima Célia Guimarães; Brienen, Roel; Castellanos, Hernán; Duivenvoorden, Joost F.; Mogollón, Hugo F.; Piedade, Maria Teresa Fernandez; Aymard C., Gerardo A.; Comiskey, James A.; Damasco, Gabriel; Dávila, Nállarett; García-Villacorta, Roosevelt; Diaz, Pablo Roberto Stevenson; Vincentini, Alberto; Emilio, Thaise; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Alonso, Alfonso; Dallmeier, Francisco; Ferreira, Leandro Valle; Neill, David; Araujo-Murakami, Alejandro; Arroyo, Luzmila; Carvalho, Fernanda Antunes; Souza, Fernanda Coelho; do Amaral, Dário Dantas; Gribel, Rogerio; Luize, Bruno Garcia; Pansonato, Marcelo Petrati; Venticinque, Eduardo; Fine, Paul; Toledo, Marisol; Baraloto, Chris; Cerón, Carlos; Engel, Julien; Henkel, Terry W.; Jimenez, Eliana M.; Maas, Paul; Mora, Maria Cristina Peñuela; Petronelli, Pascal; Revilla, Juan David Cardenas; Silveira, Marcos; Stropp, Juliana; Thomas-Caesar, Raquel; Baker, Tim R.; Daly, Doug; Paredes, Marcos Ríos; da Silva, Naara Ferreira; Fuentes, Alfredo; Jørgensen, Peter Møller; Schöngart, Jochen; Silman, Miles R.; Arboleda, Nicolás Castaño; Cintra, Bruno Barçante Ladvocat; Valverde, Fernando Cornejo; Di Fiore, Anthony; Phillips, Juan Fernando; van Andel, Tinde R.; von Hildebrand, Patricio; Barbosa, Edelcilio Marques; de Matos Bonates, Luiz Carlos; de Castro, Deborah; de Sousa Farias, Emanuelle; Gonzales, Therany; Guillaumet, Jean-Louis; Hoffman, Bruce; Malhi, Yadvinder; de Andrade Miranda, Ires Paula; Prieto, Adriana; Rudas, Agustín; Ruschell, Ademir R.; Silva, Natalino; Vela, César I. A.; Vos, Vincent A.; Zent, Eglée L.; Zent, Stanford; Cano, Angela; Nascimento, Marcelo Trindade; Oliveira, Alexandre A.; Ramirez-Angulo, Hirma; Ramos, José Ferreira; Sierra, Rodrigo; Tirado, Milton; Medina, Maria Natalia Umaña; van der Heijden, Geertje; Torre, Emilio Vilanova; Vriesendorp, Corine; Wang, Ophelia; Young, Kenneth R.; Baider, Claudia; Balslev, Henrik; de Castro, Natalia; Farfan-Rios, William; Ferreira, Cid; Mendoza, Casimiro; Mesones, Italo; Torres-Lezama, Armando; Giraldo, Ligia Estela Urrego; Villarroel, Daniel; Zagt, Roderick; Alexiades, Miguel N.; Garcia-Cabrera, Karina; Hernandez, Lionel; Huamantupa-Chuquimaco, Isau; Milliken, William; Cuenca, Walter Palacios; Pansini, Susamar; Pauletto, Daniela; Arevalo, Freddy Ramirez; Sampaio, Adeilza Felipe; Valderrama Sandoval, Elvis H.; Gamarra, Luis Valenzuela

2015-01-01

Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict that most of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century. PMID:26702442

B cells and their role in the teleost gut

PubMed Central

Korytář, Tomáš; Takizawa, Fumio

2016-01-01

Mucosal surfaces are the main route of entry for pathogens in all living organisms. In the case of teleost fish, mucosal surfaces cover the vast majority of the animal. As these surfaces are in constant contact with the environment, fish are perpetually exposed to a vast number of pathogens. Despite the potential prevalence and variety of pathogens, mucosal surfaces are primarily populated by commensal non-pathogenic bacteria. Indeed, a fine balance between these two populations of microorganisms is crucial for animal survival. This equilibrium, controlled by the mucosal immune system, maintains homeostasis at mucosal tissues. Teleost fish possess a diffuse mucosa-associated immune system in the intestine, with B cells being one of the main responders. Immunoglobulins produced by these lymphocytes are a critical line of defense against pathogens and also prevent the entrance of commensal bacteria into the epithelium. In this review we will summarize recent literature regarding the role of B-lymphocytes and immunoglobulins in gut immunity in teleost fish, with specific focus on immunoglobulin isotypes and the microorganisms, pathogenic and non-pathogenic that interact with the immune system. PMID:26995768

Central Pathways Integrating Metabolism and Reproduction in Teleosts

PubMed Central

Shahjahan, Md.; Kitahashi, Takashi; Parhar, Ishwar S.

2014-01-01

Energy balance plays an important role in the control of reproduction. However, the cellular and molecular mechanisms connecting the two systems are not well understood especially in teleosts. The hypothalamus plays a crucial role in the regulation of both energy balance and reproduction, and contains a number of neuropeptides, including gonadotropin-releasing hormone (GnRH), orexin, neuropeptide-Y, ghrelin, pituitary adenylate cyclase-activating polypeptide, α-melanocyte stimulating hormone, melanin-concentrating hormone, cholecystokinin, 26RFamide, nesfatin, kisspeptin, and gonadotropin-inhibitory hormone. These neuropeptides are involved in the control of energy balance and reproduction either directly or indirectly. On the other hand, synthesis and release of these hypothalamic neuropeptides are regulated by metabolic signals from the gut and the adipose tissue. Furthermore, neurons producing these neuropeptides interact with each other, providing neuronal basis of the link between energy balance and reproduction. This review summarizes the advances made in our understanding of the physiological roles of the hypothalamic neuropeptides in energy balance and reproduction in teleosts, and discusses how they interact with GnRH, kisspeptin, and pituitary gonadotropins to control reproduction in teleosts. PMID:24723910

Origin and evolution of the Amazonian craton

NASA Technical Reports Server (NTRS)

Gibbs, A. K.; Wirth, K. R.

1986-01-01

The Amazonian craton appears to be formed and modifed by processes much like those of the better-known Precambrian cratons, but the major events did not always follow conventional sequences nor did they occur synchronously with those of other cratons. Much of the craton's Archean style continental crust formation, recorded in granite-greenstone and high-grade terranes, occurred in the Early Proterozoic: a period of relative quiescence in many other Precambrian regions. The common Archean to Proterozoic transition in geological style did not occur here, but an analogous change from abundant marine volcanism to dominantly continental sedimentary and eruptive styles occurred later. Amazonian geology is summarized, explaining the evolution of the craton.

Resolution of ray-finned fish phylogeny and timing of diversification.

PubMed

Near, Thomas J; Eytan, Ron I; Dornburg, Alex; Kuhn, Kristen L; Moore, Jon A; Davis, Matthew P; Wainwright, Peter C; Friedman, Matt; Smith, W Leo

2012-08-21

Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the "bush at the top of the tree" that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the "Second Age of Fishes."

Evolution of the duplicated intracellular lipid-binding protein genes of teleost fishes.

PubMed

Venkatachalam, Ananda B; Parmar, Manoj B; Wright, Jonathan M

2017-08-01

Increasing organismal complexity during the evolution of life has been attributed to the duplication of genes and entire genomes. More recently, theoretical models have been proposed that postulate the fate of duplicated genes, among them the duplication-degeneration-complementation (DDC) model. In the DDC model, the common fate of a duplicated gene is lost from the genome owing to nonfunctionalization. Duplicated genes are retained in the genome either by subfunctionalization, where the functions of the ancestral gene are sub-divided between the sister duplicate genes, or by neofunctionalization, where one of the duplicate genes acquires a new function. Both processes occur either by loss or gain of regulatory elements in the promoters of duplicated genes. Here, we review the genomic organization, evolution, and transcriptional regulation of the multigene family of intracellular lipid-binding protein (iLBP) genes from teleost fishes. Teleost fishes possess many copies of iLBP genes owing to a whole genome duplication (WGD) early in the teleost fish radiation. Moreover, the retention of duplicated iLBP genes is substantially higher than the retention of all other genes duplicated in the teleost genome. The fatty acid-binding protein genes, a subfamily of the iLBP multigene family in zebrafish, are differentially regulated by peroxisome proliferator-activated receptor (PPAR) isoforms, which may account for the retention of iLBP genes in the zebrafish genome by the process of subfunctionalization of cis-acting regulatory elements in iLBP gene promoters.

Resolution of ray-finned fish phylogeny and timing of diversification

PubMed Central

Near, Thomas J.; Eytan, Ron I.; Dornburg, Alex; Kuhn, Kristen L.; Moore, Jon A.; Davis, Matthew P.; Wainwright, Peter C.; Friedman, Matt; Smith, W. Leo

2012-01-01

Ray-finned fishes make up half of all living vertebrate species. Nearly all ray-finned fishes are teleosts, which include most commercially important fish species, several model organisms for genomics and developmental biology, and the dominant component of marine and freshwater vertebrate faunas. Despite the economic and scientific importance of ray-finned fishes, the lack of a single comprehensive phylogeny with corresponding divergence-time estimates has limited our understanding of the evolution and diversification of this radiation. Our analyses, which use multiple nuclear gene sequences in conjunction with 36 fossil age constraints, result in a well-supported phylogeny of all major ray-finned fish lineages and molecular age estimates that are generally consistent with the fossil record. This phylogeny informs three long-standing problems: specifically identifying elopomorphs (eels and tarpons) as the sister lineage of all other teleosts, providing a unique hypothesis on the radiation of early euteleosts, and offering a promising strategy for resolution of the “bush at the top of the tree” that includes percomorphs and other spiny-finned teleosts. Contrasting our divergence time estimates with studies using a single nuclear gene or whole mitochondrial genomes, we find that the former underestimates ages of the oldest ray-finned fish divergences, but the latter dramatically overestimates ages for derived teleost lineages. Our time-calibrated phylogeny reveals that much of the diversification leading to extant groups of teleosts occurred between the late Mesozoic and early Cenozoic, identifying this period as the “Second Age of Fishes.” PMID:22869754

Ancient human disturbances may be skewing our understanding of Amazonian forests.

PubMed

McMichael, Crystal N H; Matthews-Bird, Frazer; Farfan-Rios, William; Feeley, Kenneth J

2017-01-17

Although the Amazon rainforest houses much of Earth's biodiversity and plays a major role in the global carbon budget, estimates of tree biodiversity originate from fewer than 1,000 forest inventory plots, and estimates of carbon dynamics are derived from fewer than 200 recensus plots. It is well documented that the pre-European inhabitants of Amazonia actively transformed and modified the forest in many regions before their population collapse around 1491 AD; however, the impacts of these ancient disturbances remain entirely unaccounted for in the many highly influential studies using Amazonian forest plots. Here we examine whether Amazonian forest inventory plot locations are spatially biased toward areas with high probability of ancient human impacts. Our analyses reveal that forest inventory plots, and especially forest recensus plots, in all regions of Amazonia are located disproportionately near archaeological evidence and in areas likely to have ancient human impacts. Furthermore, regions of the Amazon that are relatively oversampled with inventory plots also contain the highest values of predicted ancient human impacts. Given the long lifespan of Amazonian trees, many forest inventory and recensus sites may still be recovering from past disturbances, potentially skewing our interpretations of forest dynamics and our understanding of how these forests are responding to global change. Empirical data on the human history of forest inventory sites are crucial for determining how past disturbances affect modern patterns of forest composition and carbon flux in Amazonian forests.

Di- and tripeptide transport in vertebrates: the contribution of teleost fish models.

PubMed

Verri, Tiziano; Barca, Amilcare; Pisani, Paola; Piccinni, Barbara; Storelli, Carlo; Romano, Alessandro

2017-04-01

Solute Carrier 15 (SLC15) family, alias H + -coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates.

Duplicated Leptin Receptors in Two Species of Eel Bring New Insights into the Evolution of the Leptin System in Vertebrates

PubMed Central

Morini, Marina; Pasquier, Jérémy; Dirks, Ron; van den Thillart, Guido; Tomkiewicz, Jonna; Rousseau, Karine; Dufour, Sylvie; Lafont, Anne-Gaëlle

2015-01-01

Since its discovery in mammals as a key-hormone in reproduction and metabolism, leptin has been identified in an increasing number of tetrapods and teleosts. Tetrapods possess only one leptin gene, while most teleosts possess two leptin genes, as a result of the teleost third whole genome duplication event (3R). Leptin acts through a specific receptor (LEPR). In the European and Japanese eels, we identified two leptin genes, and for the first time in vertebrates, two LEPR genes. Synteny analyses indicated that eel LEPRa and LEPRb result from teleost 3R. LEPRb seems to have been lost in the teleost lineage shortly after the elopomorph divergence. Quantitative PCRs revealed a wide distribution of leptins and LEPRs in the European eel, including tissues involved in metabolism and reproduction. Noticeably, leptin1 was expressed in fat tissue, while leptin2 in the liver, reflecting subfunctionalization. Four-month fasting had no impact on the expression of leptins and LEPRs in control European eels. This might be related to the remarkable adaptation of silver eel metabolism to long-term fasting throughout the reproductive oceanic migration. In contrast, sexual maturation induced differential increases in the expression of leptins and LEPRs in the BPG-liver axis. Leptin2 was strikingly upregulated in the liver, the central organ of the reproductive metabolic challenge in teleosts. LEPRs were differentially regulated during sexual maturation, which may have contributed to the conservation of the duplicated LEPRs in this species. This suggests an ancient and positive role of the leptin system in the vertebrate reproductive function. This study brings new insights on the evolutionary history of the leptin system in vertebrates. Among extant vertebrates, the eel represents a unique case of duplicated leptins and leptin receptors as a result of 3R. PMID:25946034

Profiling of gene duplication patterns of sequenced teleost genomes: evidence for rapid lineage-specific genome expansion mediated by recent tandem duplications.

PubMed

Lu, Jianguo; Peatman, Eric; Tang, Haibao; Lewis, Joshua; Liu, Zhanjiang

2012-06-15

Gene duplication has had a major impact on genome evolution. Localized (or tandem) duplication resulting from unequal crossing over and whole genome duplication are believed to be the two dominant mechanisms contributing to vertebrate genome evolution. While much scrutiny has been directed toward discerning patterns indicative of whole-genome duplication events in teleost species, less attention has been paid to the continuous nature of gene duplications and their impact on the size, gene content, functional diversity, and overall architecture of teleost genomes. Here, using a Markov clustering algorithm directed approach we catalogue and analyze patterns of gene duplication in the four model teleost species with chromosomal coordinates: zebrafish, medaka, stickleback, and Tetraodon. Our analyses based on set size, duplication type, synonymous substitution rate (Ks), and gene ontology emphasize shared and lineage-specific patterns of genome evolution via gene duplication. Most strikingly, our analyses highlight the extraordinary duplication and retention rate of recent duplicates in zebrafish and their likely role in the structural and functional expansion of the zebrafish genome. We find that the zebrafish genome is remarkable in its large number of duplicated genes, small duplicate set size, biased Ks distribution toward minimal mutational divergence, and proportion of tandem and intra-chromosomal duplicates when compared with the other teleost model genomes. The observed gene duplication patterns have played significant roles in shaping the architecture of teleost genomes and appear to have contributed to the recent functional diversification and divergence of important physiological processes in zebrafish. We have analyzed gene duplication patterns and duplication types among the available teleost genomes and found that a large number of genes were tandemly and intrachromosomally duplicated, suggesting their origin of independent and continuous duplication. This is particularly true for the zebrafish genome. Further analysis of the duplicated gene sets indicated that a significant portion of duplicated genes in the zebrafish genome were of recent, lineage-specific duplication events. Most strikingly, a subset of duplicated genes is enriched among the recently duplicated genes involved in immune or sensory response pathways. Such findings demonstrated the significance of continuous gene duplication as well as that of whole genome duplication in the course of genome evolution.

Evolution of the myosin heavy chain gene MYH14 and its intronic microRNA miR-499: muscle-specific miR-499 expression persists in the absence of the ancestral host gene.

PubMed

Bhuiyan, Sharmin Siddique; Kinoshita, Shigeharu; Wongwarangkana, Chaninya; Asaduzzaman, Md; Asakawa, Shuichi; Watabe, Shugo

2013-07-06

A novel sarcomeric myosin heavy chain gene, MYH14, was identified following the completion of the human genome project. MYH14 contains an intronic microRNA, miR-499, which is expressed in a slow/cardiac muscle specific manner along with its host gene; it plays a key role in muscle fiber-type specification in mammals. Interestingly, teleost fish genomes contain multiple MYH14 and miR-499 paralogs. However, the evolutionary history of MYH14 and miR-499 has not been studied in detail. In the present study, we identified MYH14/miR-499 loci on various teleost fish genomes and examined their evolutionary history by sequence and expression analyses. Synteny and phylogenetic analyses depict the evolutionary history of MYH14/miR-499 loci where teleost specific duplication and several subsequent rounds of species-specific gene loss events took place. Interestingly, miR-499 was not located in the MYH14 introns of certain teleost fish. An MYH14 paralog, lacking miR-499, exhibited an accelerated rate of evolution compared with those containing miR-499, suggesting a putative functional relationship between MYH14 and miR-499. In medaka, Oryzias latipes, miR-499 is present where MYH14 is completely absent in the genome. Furthermore, by using in situ hybridization and small RNA sequencing, miR-499 was expressed in the notochord at the medaka embryonic stage and slow/cardiac muscle at the larval and adult stages. Comparing the flanking sequences of MYH14/miR-499 loci between torafugu Takifugu rubripes, zebrafish Danio rerio, and medaka revealed some highly conserved regions, suggesting that cis-regulatory elements have been functionally conserved in medaka miR-499 despite the loss of its host gene. This study reveals the evolutionary history of the MYH14/miRNA-499 locus in teleost fish, indicating divergent distribution and expression of MYH14 and miR-499 genes in different teleost fish lineages. We also found that medaka miR-499 was even expressed in the absence of its host gene. To our knowledge, this is the first report that shows the conversion of intronic into non-intronic miRNA during the evolution of a teleost fish lineage.

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.

The Tsimane' Amazonian Panel Study (TAPS): Nine years (2002-2010) of annual data available to the public.

PubMed

Leonard, William R; Reyes-García, Victoria; Tanner, Susan; Rosinger, Asher; Schultz, Alan; Vadez, Vincent; Zhang, Rebecca; Godoy, Ricardo

2015-12-01

This brief communication contains a description of the 2002-2010 annual panel collected by the Tsimane' Amazonian Panel Study team. The study took place among the Tsimane', a native Amazonian society of forager-horticulturalists. The team tracked a wide range of socio-economic and anthropometric variables from all residents (633 adults ≥16 years; 820 children) in 13 villages along the Maniqui River, Department of Beni. The panel is ideally suited to examine how market exposure and modernization affect the well-being of a highly autarkic population and to examine human growth in a non-Western rural setting. Copyright © 2015 Elsevier B.V. All rights reserved.

Antiparasitic activity, histopathology and physiology of Colossoma macropomum (tambaqui) exposed to the essential oil of Lippia sidoides (Verbenaceae).

PubMed

Soares, Bruna Viana; Neves, Lígia Rigôr; Ferreira, Drielly Oliveira; Oliveira, Marcos Sidney Brito; Chaves, Francisco Célio Maia; Chagas, Edsandra Campos; Gonçalves, Raissa Alves; Tavares-Dias, Marcos

2017-01-30

In vivo and in vitro antiparasitic activity of the essential oil of Lippia sidoides and blood and histological alterations were assessed in Colossoma macropomum (tambaqui). Essential oil concentrations of 10, 20, 40, 80, 160 and 320mg/L were assayed in vitro against monogenoideans Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri from fish gills. Lippia sidoides essential oil concentrations of 320 and 160mg/L were 100% effective against monogenoideans in 10min and 1h of exposure, respectively. However, the effectiveness of 100% concentrations of 80mg/L and 40mg/L occurred in 3 and 6h, respectively. In the in vivo tests, juvenile fish were submitted to 60min of baths with 10mg/L and 15min of baths with 20mg/L of the essential oil of L. sidoides. These therapeutic baths were not efficient against Ichthyophthirius multifiliis, and monogenoideans present in the gills of C. macropomum. In addition, 10 and 20mg/L of the essential oil of L. sidoides caused an anesthetic effect on the fish and did not influence total glucose and protein plasma levels; however, it decreased the number of total erythrocytes in fish exposed to the higher concentration of this essential oil. Severe alterations and irreversible damage were observed in the fish gills just after L. sidoides essential oil baths and after 24h of recovery. The most recurrent lesions found were hyperplasia and fusion of the lamellar epithelium, vasodilation, detachment of the gill epithelium and lamellar aneurism, epithelial breakdown with hemorrhage, congestion, edema and necrosis, proliferation of the mucous cells and chloride cells and lamellar hypertrophy. Therefore, since the essential oil of L. sidoides has in vitro antiparasitic activity and low concentrations of it have shown toxic effects, the bioactive potential of its main chemical components should be investigated, as well as more efficient forms of its administration in therapeutic baths in order to eliminate fish parasites. Copyright © 2016 Elsevier B.V. All rights reserved.

A new genus of predatory katydids (Orthoptera: Tettigoniidae: Listroscelidinae) from the Amazonian Rainforest.

PubMed

Mendes, Diego Matheus De Mello; Chamorro-Rengifo, Juliana; Rafael, José Albertino

2016-09-12

Most of the predatory katydids Listroscelidini species known were described from the Brazilian Atlantic Forest. Here a new genus and species from the Amazonian Rainforest is described. Based on its morphological characteristics, this new genus represents an intermediate form between two closely related genera, Listroscelis Serville and Monocerophora Walker.

Litter mercury deposition in the Amazonian rainforest.

PubMed

Fostier, Anne Hélène; Melendez-Perez, José Javier; Richter, Larissa

2015-11-01

The objective of this work was to assess the flux of atmospheric mercury transferred to the soil of the Amazonian rainforest by litterfall. Calculations were based on a large survey of published and unpublished data on litterfall and Hg concentrations in litterfall samples from the Amazonian region. Litterfall based on 65 sites located in the Amazon rainforest averaged 8.15 ± 2.25 Mg ha(-1) y(-1). Average Hg concentrations were calculated from nine datasets for fresh tree leaves and ten datasets for litter, and a median concentration of 60.5 ng Hg g(-1) was considered for Hg deposition in litterfall, which averaged 49 ± 14 μg m(-2) yr(-1). This value was used to estimate that in the Amazonian rainforest, litterfall would be responsible for the annual removing of 268 ± 77 Mg of Hg, approximately 8% of the total atmospheric Hg deposition to land. The impact of the Amazon deforestation on the Hg biogeochemical cycle is also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

The circadian clock of teleost fish: a comparative analysis reveals distinct fates for duplicated genes.

PubMed

Toloza-Villalobos, Jessica; Arroyo, José Ignacio; Opazo, Juan C

2015-01-01

The circadian clock is a central oscillator that coordinates endogenous rhythms. Members of six gene families underlie the metabolic machinery of this system. Although this machinery appears to correspond to a highly conserved genetic system in metazoans, it has been recognized that vertebrates possess a more diverse gene inventory than that of non-vertebrates. This difference could have originated in the two successive rounds of whole-genome duplications that took place in the common ancestor of the group. Teleost fish underwent an extra event of whole-genome duplication, which is thought to have provided an abundance of raw genetic material for the biological innovations that facilitated the radiation of the group. In this study, we assessed the relative contributions of whole-genome duplication and small-scale gene duplication to generate the repertoire of genes associated with the circadian clock of teleost fish. To achieve this goal, we annotated genes from six gene families associated with the circadian clock in eight teleost fish species, and we reconstructed their evolutionary history by inferring phylogenetic relationships. Our comparative analysis indicated that teleost species possess a variable repertoire of genes related to the circadian clock gene families and that the actual diversity of these genes has been shaped by a variety of phenomena, such as the complete deletion of ohnologs, the differential retention of genes, and lineage-specific gene duplications. From a functional perspective, the subfunctionalization of two ohnolog genes (PER1a and PER1b) in zebrafish highlights the power of whole-genome duplications to generate biological diversity.

Effect of Parathion-Methyl on Amazonian Fish and Freshwater Invertebrates: A Comparison of Sensitivity with Temperate Data

PubMed Central

Geber-Corrêa, Rachel; Campos, Paola S.; Garcia, Marcos V. B.; Waichman, Andrea V.; van den Brink, Paul J.

2009-01-01

Parathion-methyl is an organophosphorous insecticide that is widely used in agricultural production sites in the Amazon. The use of this pesticide might pose a potential risk for the biodiversity and abundance of fish and invertebrate species inhabiting aquatic ecosystems adjacent to the agricultural fields. Due to a lack of toxicity data for Amazonian species, safe environmental concentrations used to predict the ecological risks of parathion-methyl in the Amazon are based on tests performed with temperate species, although it is unknown whether the sensitivity of temperate species is representative for those of Amazonian endemic species. To address this issue, the acute toxic effect (LC50–96 h) of parathion-methyl was assessed on seven fish and five freshwater invertebrate species endemic to the Amazon. These data were used to compare their pesticide sensitivity with toxicity data for temperate species collected from the literature. The interspecies sensitivity was compared using the Species Sensitivity Distribution (SSD) concept. The results of this study suggest that Amazonian species are no more, or less, sensitive to parathion-methyl than their temperate counterparts, with LC50 values ranging from 2900 to 7270 μg/L for fish and from 0.3 to 319 μg/L for freshwater arthropods. Consequently, this evaluation supports the initial use of toxicity data of temperate fish and freshwater invertebrate species for assessing the effects of parathion-methyl on Amazonian freshwater ecosystems. PMID:19847472

Ancient human disturbances may be skewing our understanding of Amazonian forests

PubMed Central

McMichael, Crystal N. H.; Matthews-Bird, Frazer; Farfan-Rios, William; Feeley, Kenneth J.

2017-01-01

Although the Amazon rainforest houses much of Earth’s biodiversity and plays a major role in the global carbon budget, estimates of tree biodiversity originate from fewer than 1,000 forest inventory plots, and estimates of carbon dynamics are derived from fewer than 200 recensus plots. It is well documented that the pre-European inhabitants of Amazonia actively transformed and modified the forest in many regions before their population collapse around 1491 AD; however, the impacts of these ancient disturbances remain entirely unaccounted for in the many highly influential studies using Amazonian forest plots. Here we examine whether Amazonian forest inventory plot locations are spatially biased toward areas with high probability of ancient human impacts. Our analyses reveal that forest inventory plots, and especially forest recensus plots, in all regions of Amazonia are located disproportionately near archaeological evidence and in areas likely to have ancient human impacts. Furthermore, regions of the Amazon that are relatively oversampled with inventory plots also contain the highest values of predicted ancient human impacts. Given the long lifespan of Amazonian trees, many forest inventory and recensus sites may still be recovering from past disturbances, potentially skewing our interpretations of forest dynamics and our understanding of how these forests are responding to global change. Empirical data on the human history of forest inventory sites are crucial for determining how past disturbances affect modern patterns of forest composition and carbon flux in Amazonian forests. PMID:28049821

FoxP2 Expression in a Highly Vocal Teleost Fish with Comparisons to Tetrapods.

PubMed

Pengra, Ian G G; Marchaterre, Margaret A; Bass, Andrew H

2018-04-19

Motivated by studies of speech deficits in humans, several studies over the past two decades have investigated the potential role of a forkhead domain transcription factor, FoxP2, in the central control of acoustic signaling/vocalization among vertebrates. Comparative neuroanatomical studies that mainly include mammalian and avian species have mapped the distribution of FoxP2 expression in multiple brain regions that imply a greater functional significance beyond vocalization that might be shared broadly across vertebrate lineages. To date, reports for teleost fish have been limited in number and scope to nonvocal species. Here, we map the neuroanatomical distribution of FoxP2 mRNA expression in a highly vocal teleost, the plainfin midshipman (Porichthys notatus). We report an extensive overlap between FoxP2 expression and vocal, auditory, and steroid-signaling systems with robust expression at multiple sites in the telencephalon, the preoptic area, the diencephalon, and the midbrain. Label was far more restricted in the hindbrain though robust in one region of the reticular formation. A comparison with other teleosts and tetrapods suggests an evolutionarily conserved FoxP2 phenotype important to vocal-acoustic and, more broadly, sensorimotor function among vertebrates. © 2018 S. Karger AG, Basel.

Evolutionary and Functional Relationships of B Cells from Fish and Mammals: Insights into their Novel Roles in Phagocytosis and Presentation of Particulate Antigen

PubMed Central

Sunyer, J. Oriol

2012-01-01

The evolutionary origins of Ig-producing B cells appear to be linked to the emergence of fish in this planet. There are three major classes of living fish species, which from most primitive to modern they are referred to as agnathan (e.g., lampreys), Chondrichthyes (e.g., sharks), and teleost fish (e.g., rainbow trout). Agnathans do not have immunoglobulin-producing B cells, however these fish contain a subset of lymphocytes-like cells producing type B variable lymphocyte receptors (VLRBs) that appear to act as functional analogs of immunoglobulins. Chondrichthyes fish represent the most primitive living species containing bona-fide immunoglobulin-producing B cells. Their B cells are known to secrete three types of antibodies, IgM, IgW and IgNAR. Teleost fish are also called bony fish since they represent the most ancient living species containing true bones. Teleost B cells produce three different immunoglobulin isotypes, IgM, IgD and the recently described IgT. While teleost IgM is the principal player in systemic immunity, IgT appears to be a teleost immunoglobulin class specialized in mucosal immune responses. Thus far, three major B cell lineages have been described in teleost, those expressing either IgT or IgD, and the most common lineage which co-expresses IgD and IgM. A few years ago, the study of teleost fish B cells revealed for the first time in vertebrates the existence of B cell subsets with phagocytic and intracellular bactericidal capacities. This finding represented a paradigm shift as professional phagocytosis was believed to be exclusively performed by some cells of the myeloid lineage (i.e., macrophages, monocytes, neutrophils). This phagocytic capacity was also found in amphibians and reptiles, suggesting that this innate capacity was evolutionarily conserved in certain B cell subsets of vertebrates. Recently, the existence of subsets of B cells with phagocytic and bactericidal abilities have also been confirmed in mammals. Moreover, it has been shown that phagocytic B-1 B cells have a potent ability to present particulate antigen to CD4+ T cells. Thus, studies carried out originally on fish B cells have lead to the discovery of new innate and adaptive roles of B cells in mammals. This review will concentrate on the evolutionary and functional relationships of fish and mammalian B cells, focusing mainly on the newly discovered roles of these cells in phagocytosis, intracellular killing and presentation of particulate antigen. PMID:22394174

Thrash, flip, or jump: the behavioral and functional continuum of terrestrial locomotion in teleost fishes.

PubMed

Gibb, Alice C; Ashley-Ross, Miriam A; Hsieh, S Tonia

2013-08-01

Moving on land versus in water imposes dramatically different requirements on the musculoskeletal system. Although many limbed vertebrates, such as salamanders and prehistoric tetrapodomorphs, have an axial system specialized for aquatic locomotion and an appendicular system adapted for terrestrial locomotion, diverse extant teleosts use the axial musculoskeletal system (body plus caudal fin) to move in these two physically disparate environments. In fact, teleost fishes living at the water's edge demonstrate diversity in natural history that is reflected in a variety of terrestrial behaviors: (1) species that have only incidental contact with land (such as largemouth bass, Micropterus) will repeatedly thrash, which can roll an individual downhill, but cannot produce effective overland movements, (2) species that have occasional contact with land (like Gambusia, the mosquitofish, which evade predators by stranding themselves) will produce directed terrestrial movement via a tail-flip jump, and (3) species that spend more than half of their lives on land (like the mudskipper, Periopthalmus) will produce a prone-jump, a behavior that allows the fish to anticipate where it will land at the end of the flight phase. Both tail-flip and prone jumps are characterized by a two-phase movement consisting of body flexion followed by extension-a movement pattern that is markedly similar to the aquatic fast-start. Convergence in kinematic pattern between effective terrestrial behaviors and aquatic fast starts suggests that jumps are an exaptation of a neuromuscular system that powers unsteady escape behaviors in the water. Despite such evidence that terrestrial behaviors evolved from an ancestral behavior that is ubiquitous among teleosts, some teleosts are unable to move effectively on land-possibly due to morphological trade-offs, wherein specialization for one environment comes at a cost to performance in the other. Indeed, upon emergence onto land, gravity places an increased mechanical load on the body, which may limit the maximum size of fish that can produce terrestrial locomotion via jumping. In addition, effective terrestrial locomotor performance may require a restructuring of the musculoskeletal system that directly conflicts with the low-drag, fusiform body shape that enhances steady swimming performance. Such biomechanical trade-offs may constrain which teleost species are able to make the evolutionary transition to life on land. Here, we synthesize the current knowledge of intermittent terrestrial locomotion in teleosts and demonstrate that extant fishes represent an important model system for elucidating fundamental evolutionary mechanisms and defining the physiological constraints that must be overcome to permit life in both the aquatic and terrestrial realms.

The Perceptions of Knowledge and Learning of Amazonian Indigenous Teacher Education Students

ERIC Educational Resources Information Center

Veintie, Tuija; Holm, Gunilla

2010-01-01

This study focuses on the perceptions of knowledge and learning by indigenous students in an intercultural bilingual teacher education programme in Amazonian Ecuador. The study framed within postcolonial and critical theory attempts to create a space for the indigenous students to speak about their own views through the use of photography and…

The responses of understorey birds to forest fragmentation, logging and wildfires: An Amazonian synthesis

Treesearch

J. Barlow; C. A. Peres; L. M. P. Henr¡ques; P. C. Stouffer; J. M. Wunderle

2006-01-01

We combine mist-net data from 24 disturbance treatments taken from seven studies on the responses of understorey Amazonian birds to selective logging, single and recurrent wildfires, and habitat fragmentation. The different disturbance treatments had distinct effects on avian guild structure, and fire disturbance and the isolation of forest patches resulted in bird...

Effects of reduced-impact logging and forest physiognomy on bat populations of lowland Amazonian forest.

Treesearch

Steven J. Presley; Michael R. Willig; Wunderle Jr. Joseph M.; Luis Nélio Saldanha

2008-01-01

1.As human population size increases, demand for natural resources will increase. Logging pressure related to increasing demands continues to threaten remote areas of Amazonian forest. A harvest protocol is required to provide renewable timber resources that meet consumer needs while minimizing negative effects on biodiversity and ecosystem services. Reduced-impact...

Protecting biodiversity in situ in the Amazonian Region of Brazil

Treesearch

Claudia Sellier

2007-01-01

Brazil has approximately 3.6 million km2 (1.4 million mi2) of forest, with the majority concentrated in the Amazonian region. The Atlantic Forest was reduced to less than 8 percent of its original territory. Development activities are being implemented without consideration for the local environment, causing both biodiversity and habitat losses. Establishment of...

Amazonian forest dieback under climate-carbon cycle projections for the 21st century

NASA Astrophysics Data System (ADS)

Cox, P. M.; Betts, R. A.; Collins, M.; Harris, P. P.; Huntingford, C.; Jones, C. D.

The first GCM climate change projections to include dynamic vegetation and an interactive carbon cycle produced a very significant amplification of global warming over the 21st century. Under the IS92a ``business as usual'' emissions scenario CO2 concentrations reached about 980ppmv by 2100, which is about 280ppmv higher than when these feedbacks were ignored. The major contribution to the increased CO2 arose from reductions in soil carbon because global warming is assumed to accelerate respiration. However, there was also a lesser contribution from an alarming loss of the Amazonian rainforest. This paper describes the phenomenon of Amazonian forest dieback under elevated CO2 in the Hadley Centre climate-carbon cycle model.

Occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil.

PubMed

Borges, Joāo Carlos Gomes; Alves, Leucio Câmara; Faustino, Maria Aparecida da Gloria; Marmontel, Miriam

2011-12-01

Infections by Cryptosporidium spp. in aquatic mammals is a major concern due to the possibility of the waterborne transmission of oocysts. The aim of the present study was to report the occurrence of Cryptosporidium spp. in Antillean manatees (Trichechus manatus) and Amazonian manatees (Trichechus inunguis) from Brazil. Fecal samples were collected and processed using Kinyoun's method. Positive samples were also submitted to the direct immunofluorescence test. The results revealed the presence of Cryptosporidium spp. oocysts in 12.5% (17/136) of the material obtained from the Antillean manatees and in 4.3% (05/115) of the samples from the Amazonian manatees. Cryptosporidium spp. infection was more prevalent in captive animals than in free-ranging specimens.

Gene evolution and gene expression after whole genome duplication in fish: the PhyloFish database.

PubMed

Pasquier, Jeremy; Cabau, Cédric; Nguyen, Thaovi; Jouanno, Elodie; Severac, Dany; Braasch, Ingo; Journot, Laurent; Pontarotti, Pierre; Klopp, Christophe; Postlethwait, John H; Guiguen, Yann; Bobe, Julien

2016-05-18

With more than 30,000 species, ray-finned fish represent approximately half of vertebrates. The evolution of ray-finned fish was impacted by several whole genome duplication (WGD) events including a teleost-specific WGD event (TGD) that occurred at the root of the teleost lineage about 350 million years ago (Mya) and more recent WGD events in salmonids, carps, suckers and others. In plants and animals, WGD events are associated with adaptive radiations and evolutionary innovations. WGD-spurred innovation may be especially relevant in the case of teleost fish, which colonized a wide diversity of habitats on earth, including many extreme environments. Fish biodiversity, the use of fish models for human medicine and ecological studies, and the importance of fish in human nutrition, fuel an important need for the characterization of gene expression repertoires and corresponding evolutionary histories of ray-finned fish genes. To this aim, we performed transcriptome analyses and developed the PhyloFish database to provide (i) de novo assembled gene repertoires in 23 different ray-finned fish species including two holosteans (i.e. a group that diverged from teleosts before TGD) and 21 teleosts (including six salmonids), and (ii) gene expression levels in ten different tissues and organs (and embryos for many) in the same species. This resource was generated using a common deep RNA sequencing protocol to obtain the most exhaustive gene repertoire possible in each species that allows between-species comparisons to study the evolution of gene expression in different lineages. The PhyloFish database described here can be accessed and searched using RNAbrowse, a simple and efficient solution to give access to RNA-seq de novo assembled transcripts.

Endocrine control of sexual behavior in teleost fish.

PubMed

Munakata, Arimune; Kobayashi, Makito

2010-02-01

Sexual behavior is one of the most profound events during the life cycle of animals that reproduce sexually. After completion of gonadal development that is mediated by various hormones, oviparous teleosts perform a suite of behaviors, often termed as spawning behavior. This is particularly important for teleosts that have their gametes fertilized externally as the behavior patterns ensures the close proximity of both sexes for gamete release, fusion and ultimately the production of offspring. As in other vertebrates, sexual behavior of fish is also under the control of hormones. Testicular androgen is a requirement for male sexual behavior to occur in most fish species that have been studied. Unlike tetrapods, however, ovarian estrogen does not appear to be essential for the occurrence of female sexual behavior for fish that have their gametes fertilized externally. Prostaglandins produced in the ovary after ovulation act as a trigger in some teleosts to induce female sexual behavior. Potentiating effects of gonadotropin-releasing hormone in the brain on sexual behavior are reported in some species. Under endocrine regulation, male and female fish exhibit gender-typical behavior during spawning, but in some fish species there is also some plasticity in their sexual behavior. Sex changing fish can perform both male-typical and female-typical sexual behaviors during their lifetime and this sexual plasticity can also be observed in non-sex changing fish when undergoing hormonal treatment. Although the neuroanatomical basis is not clear in fish, results of field and laboratory observations suggest that some teleosts possess a sexually bipotential brain which can regulate two types of behaviors unlike most other vertebrates which have a discrete sex differentiation of their brain and can only perform gender-typical sexual behavior. Copyright 2009 Elsevier Inc. All rights reserved.

A molecule in teleost fish, related with human MHC-encoded G6F, has a cytoplasmic tail with ITAM and marks the surface of thrombocytes and in some fishes also of erythrocytes.

PubMed

Ohashi, Ken; Takizawa, Fumio; Tokumaru, Norihiro; Nakayasu, Chihaya; Toda, Hideaki; Fischer, Uwe; Moritomo, Tadaaki; Hashimoto, Keiichiro; Nakanishi, Teruyuki; Dijkstra, Johannes Martinus

2010-08-01

In teleost fish, a novel gene G6F-like was identified, encoding a type I transmembrane molecule with four extracellular Ig-like domains and a cytoplasmic tail with putative tyrosine phosphorylation motifs including YxN and an immunoreceptor tyrosine-based activation motif (ITAM). G6F-like maps to a teleost genomic region where stretches corresponding to human chromosomes 6p (with the MHC), 12p (with CD4 and LAG-3), and 19q are tightly linked. This genomic organization resembles the ancestral "Ur-MHC" proposed for the jawed vertebrate ancestor. The deduced G6F-like molecule shows sequence similarity with members of the CD4/LAG-3 family and with the human major histocompatibility complex-encoded thrombocyte marker G6F. Despite some differences in molecular organization, teleost G6F-like and tetrapod G6F seem orthologous as they map to similar genomic location, share typical motifs in transmembrane and cytoplasmic regions, and are both expressed by thrombocytes/platelets. In the crucian carps goldfish (Carassius auratus auratus) and ginbuna (Carassius auratus langsdorfii), G6F-like was found expressed not only by thrombocytes but also by erythrocytes, supporting that erythroid and thromboid cells in teleost fish form a hematopoietic lineage like they do in mammals. The ITAM-bearing of G6F-like suggests that the molecule plays an important role in cell activation, and G6F-like expression by erythrocytes suggests that these cells have functional overlap potential with thrombocytes.

Wood decomposition in Amazonian hydropower reservoirs: An additional source of greenhouse gases

NASA Astrophysics Data System (ADS)

Abril, Gwenaël; Parize, Marcelo; Pérez, Marcela A. P.; Filizola, Naziano

2013-07-01

Amazonian hydroelectric reservoirs produce abundant carbon dioxide and methane from large quantities of flooded biomass that decompose anaerobically underwater. Emissions are extreme the first years after impounding and progressively decrease with time. To date, only water-to-air fluxes have been considered in these estimates. Here, we investigate in two Amazonian reservoirs (Balbina and Petit Saut) the fate of above water standing dead trees, by combining a qualitative analysis of wood state and density through time and a quantitative analysis of the biomass initially flooded. Dead wood was much more decomposed in the Balbina reservoir 23 years after flooding than in the Petit Saut reservoir 10 years after flooding. Termites apparently played a major role in wood decomposition, occurring mainly above water, and resulting in a complete conversion of this carbon biomass into CO2 and CH4 at a timescale much shorter than reservoir operation. The analysis of pre-impounding wood biomass reveals that above-water decomposition in Amazonian reservoirs is a large, previously unrecognized source of carbon emissions to the atmosphere, representing 26-45% of the total reservoir flux integrated over 100 years. Accounting for both below- and above-water fluxes, we could estimate that each km2 of Amazonian forest converted to reservoir would emit over 140 Gg CO2-eq in 100 years. Hydropower plants in the Amazon should thus generate 0.25-0.4 MW h per km2 flooded area to produce lower greenhouse gas emissions than gas power plants. They also have the disadvantage to emit most of their greenhouse gases the earliest years of operation.

Urea tolerance of myofibrillar proteins of two elasmobranchs: Squalus acanthias and Raja tengu.

PubMed

Hasnain, A; Yasui, T

1986-09-01

Some biochemical properties of actomyosin and myosin from elasmobranchs, Squalus acanthias and Raja tengu are compared with those of a freshwater (Cyprinus carpio) and a marine teleost (Seriola quinquiradiata). Whereas Ca2+-ATPase of teleost actomyosins are more stable in the absence of urea, the reverse is true for elasmobranchs up to 1.0 M urea. In contrast to that of teleosts, the Mg2+-ATPase of S. acanthias actomyosin shows an activation in the presence of urea, where as that of R. tengu persists. Below 1.0 M urea, there is low incorporation of DTNB into thiols of elasmobranch myosins, and losses in alpha-helicity are reversible up to 5.0 M urea. The results, thus, demonstrate that for a certain concentration of urea, elasmobranch myofibrillar proteins may exhibit a group specific tolerance to urea.

A new species of Acroleptus Bourgeois (Coleoptera: Lycidae) from the Brazilian Amazonian rainforest, with a note on its homonymy with Acroleptus Cabanis (Aves).

PubMed

Ferreira, Vinicius S

2015-04-24

Acroleptus costae sp. nov. is described from the Brazilian Amazonian rainforest, raising the diversity of the formerly monotypic genus to two known species. The validity of Acroleptus Bourgeois, 1886 (Insecta) is maintained while Acroleptus Cabanis, 1861 (Aves) is considered to be an incorrect subsequent spelling.

Amazonian foods and implications for human biology.

PubMed

Dufour, Darna L; Piperata, Barbara A; Murrieta, Rui S S; Wilson, Warren M; Williams, Drake D

2016-07-01

Diets of subsistence-based Amazonian populations have been linked to local resources, but are changing with market penetration. To review the available data on traditional Amazonian foods and diets and evaluate their implications for human biology as a step toward understanding nutrition transitions in the region. This study used the Human Relations Area Files for information on the diets of Amerindian groups in the Amazon Basin from 1950 to the present, and used other published sources and the authors' own data. Data on food use was identified for only nine groups and dietary intake data for individuals in only three of the groups. A diet based on starchy staples (manioc and plantains) and fish, supplemented with a limited variety of other plant and animal foods, was found. Bitter manioc-based foods were associated with the consumption of cyanogens and fish with the consumption of mercury. Diets of adults appear to be adequate in energy and protein and low in fats. Children's diets were not well documented. Based on the limited available data, Amazonian diets are restricted in variety, but appear to be adequate in energy and protein for adults, but likely insufficiently nutrient-dense for children.

Extinction risks of Amazonian plant species.

PubMed

Feeley, Kenneth J; Silman, Miles R

2009-07-28

Estimates of the number, and preferably the identity, of species that will be threatened by land-use change and habitat loss are an invaluable tool for setting conservation priorities. Here, we use collections data and ecoregion maps to generate spatially explicit distributions for more than 40,000 vascular plant species from the Amazon basin (representing more than 80% of the estimated Amazonian plant diversity). Using the distribution maps, we then estimate the rates of habitat loss and associated extinction probabilities due to land-use changes as modeled under 2 disturbance scenarios. We predict that by 2050, human land-use practices will have reduced the habitat available to Amazonian plant species by approximately 12-24%, resulting in 5-9% of species becoming "committed to extinction," significantly fewer than other recent estimates. Contrary to previous studies, we find that the primary determinant of habitat loss and extinction risk is not the size of a species' range, but rather its location. The resulting extinction risk estimates are a valuable conservation tool because they indicate not only the total percentage of Amazonian plant species threatened with extinction but also the degree to which individual species and habitats will be affected by current and future land-use changes.

Tall Amazonian forests are less sensitive to precipitation variability

NASA Astrophysics Data System (ADS)

Giardina, Francesco; Konings, Alexandra G.; Kennedy, Daniel; Alemohammad, Seyed Hamed; Oliveira, Rafael S.; Uriarte, Maria; Gentine, Pierre

2018-06-01

Climate change is altering the dynamics, structure and function of the Amazon, a biome deeply connected to the Earth's carbon cycle. Climate factors that control the spatial and temporal variations in forest photosynthesis have been well studied, but the influence of forest height and age on this controlling effect has rarely been considered. Here, we present remote sensing observations of solar-induced fluorescence (a proxy for photosynthesis), precipitation, vapour-pressure deficit and canopy height, together with estimates of forest age and aboveground biomass. We show that photosynthesis in tall Amazonian forests, that is, forests above 30 m, is three times less sensitive to precipitation variability than in shorter (less than 20 m) forests. Taller Amazonian forests are also found to be older, have more biomass and deeper rooting systems1, which enable them to access deeper soil moisture and make them more resilient to drought. We suggest that forest height and age are an important control of photosynthesis in response to interannual precipitation fluctuations. Although older and taller trees show less sensitivity to precipitation variations, they are more susceptible to fluctuations in vapour-pressure deficit. Our findings illuminate the response of Amazonian forests to water stress, droughts and climate change.

Osmoregulatory actions of the GH/IGF axis in non-salmonid teleosts

USGS Publications Warehouse

Mancera, J.M.; McCormick, S.D.

1998-01-01

Salmonid fishes provided the first findings on the influence of the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis on osmoregulation in teleost fishes. Recent studies on non-salmonid species, however, indicate that this physiological action of the GH/IGF-I axis is not restricted to salmonids or anadromous fishes. GH-producing cells in the pituitary of fish acclimated to different salinities show different degrees of activation depending on the species studied. Plasma GH levels either increase or do not change after transfer of fish from freshwater to seawater. Treatment with GH or IGF-I increases salinity tolerance and/or increases gill Na+,K+-ATPase activity of killifish (Fundulus heteroclitus), tilapia (Oreochromis mossambicus and Oreochromisniloticus) and striped bass (Morone saxatilis). As in salmonids, a positive interaction between GH and cortisol for improving hypoosmoregulatory capacity has been described in tilapia (O. mossambicus). Research on the osmoregulatory role of the GH/IGF-I axis is derived from a small number of teleost species. The study of more species with different osmoregulary patterns will be necessary to fully clarify the osmoregulatory role of GH/IGF-I axis in fish. The available data does suggest, however, that the influence of the GH/IGF-I axis on osmoregulation may be a common feature of euryhalinity in teleosts.

Rhythmic chewing with oral jaws in teleost fishes: a comparison with amniotes.

PubMed

Gintof, Chris; Konow, Nicolai; Ross, Callum F; Sanford, Christopher P J

2010-06-01

Intra-oral prey processing (chewing) using the mandibular jaws occurs more extensively among teleost fishes than previously documented. The lack of muscle spindles, gamma-motoneurons and periodontal afferents in fishes makes them useful for testing hypotheses regarding the relationship between these sensorimotor components and rhythmic chewing in vertebrates. Electromyography (EMG) data from the adductor mandibulae (AM) were used to quantify variation in chew cycle duration in the bowfin Amia, three osteoglossomorphs (bony-tongues), four salmonids and one esocid (pike). All species chewed prey using their oral jaw in repetitive trains of between 3 and 30 consecutive chews, a pattern that resembles cyclic chewing in amniote vertebrates. Variance in rhythmicity was compared within and between lineages using coefficients of variation and Levene's test for homogeneity of variance. These comparisons revealed that some teleosts exhibit degrees of rhythmicity that are comparable to mammalian mastication and higher than in lepidosaurs. Moreover, chew cycle durations in fishes, as in mammals, scale positively with mandible length. Chewing among basal teleosts may be rhythmic because it is stereotyped and inflexible, the result of patterned interactions between sensory feedback and a central pattern generator, because the lack of a fleshy tongue renders jaw-tongue coordination unnecessary and/or because stereotyped opening and closing movements are important for controlling fluid flow in the oral cavity.

Life in the unthinking depths: energetic constraints on encephalization in marine fishes.

PubMed

Iglesias, T L; Dornburg, A; Brandley, M C; Alfaro, M E; Warren, D L

2015-05-01

Several hypotheses have been proposed to explain the limitation of brain size in vertebrates. Here, we test three hypotheses of brain size evolution using marine teleost fishes: the direct metabolic constraints hypothesis (DMCH), the expensive tissue hypothesis and the temperature-dependent hypothesis. Our analyses indicate that there is a robust positive correlation between encephalization and basal metabolic rate (BMR) that spans the full range of depths occupied by teleosts from the epipelagic (< 200 m), mesopelagic (200-1000 m) and bathypelagic (> 4000 m). Our results disentangle the effects of temperature and metabolic rate on teleost brain size evolution, supporting the DMCH. Our results agree with previous findings that teleost brain size decreases with depth; however, we also recover a negative correlation between trophic level and encephalization within the mesopelagic zone, a result that runs counter to the expectations of the expensive tissue hypothesis. We hypothesize that mesopelagic fishes at lower trophic levels may be investing more in neural tissue related to the detection of small prey items in a low-light environment. We recommend that comparative encephalization studies control for BMR in addition to controlling for body size and phylogeny. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Functional significance of GnRH and kisspeptin, and their cognate receptors in teleost reproduction.

PubMed

Gopurappilly, Renjitha; Ogawa, Satoshi; Parhar, Ishwar S

2013-01-01

Guanine nucleotide binding protein (G-protein)-coupled receptors (GPCRs) are eukaryotic transmembrane proteins found in all living organisms. Their versatility and roles in several physiological processes make them the single largest family of drug targets. Comparative genomic studies using various model organisms have provided useful information about target receptors. The similarity of the genetic makeup of teleosts to that of humans and other vertebrates aligns with the study of GPCRs. Gonadotropin-releasing hormone (GnRH) represents a critical step in the reproductive process through its cognate GnRH receptors (GnRHRs). Kisspeptin (Kiss1) and its cognate GPCR, GPR54 (=kisspeptin receptor, Kiss-R), have recently been identified as a critical signaling system in the control of reproduction. The Kiss1/Kiss-R system regulates GnRH release, which is vital to pubertal development and vertebrate reproduction. This review highlights the physiological role of kisspeptin-Kiss-R signaling in the reproductive neuroendocrine axis in teleosts through the modulation of GnRH release. Moreover, we also review the recent developments in GnRHR and Kiss-R with respect to their structural variants, signaling mechanisms, ligand interactions, and functional significance. Finally, we discuss the recent progress in identifying many teleost GnRH-GnRHR and kisspeptin-Kiss-R systems and consider their physiological significance in the control of reproduction.

Food Web Structure Shapes the Morphology of Teleost Fish Brains.

PubMed

Edmunds, Nicholas B; McCann, Kevin S; Laberge, Frédéric

2016-01-01

Previous work showed that teleost fish brain size correlates with the flexible exploitation of habitats and predation abilities in an aquatic food web. Since it is unclear how regional brain changes contribute to these relationships, we quantitatively examined the effects of common food web attributes on the size of five brain regions in teleost fish at both within-species (plasticity or natural variation) and between-species (evolution) scales. Our results indicate that brain morphology is influenced by habitat use and trophic position, but not by the degree of littoral-pelagic habitat coupling, despite the fact that the total brain size was previously shown to increase with habitat coupling in Lake Huron. Intriguingly, the results revealed two potential evolutionary trade-offs: (i) relative olfactory bulb size increased, while relative optic tectum size decreased, across a trophic position gradient, and (ii) the telencephalon was relatively larger in fish using more littoral-based carbon, while the cerebellum was relatively larger in fish using more pelagic-based carbon. Additionally, evidence for a within-species effect on the telencephalon was found, where it increased in size with trophic position. Collectively, these results suggest that food web structure has fundamentally contributed to the shaping of teleost brain morphology. © 2016 S. Karger AG, Basel.

Missing in Amazonian jungle: a case report of skeletal evidence for dismemberment.

PubMed

Delabarde, Tania; Ludes, Bertrand

2010-07-01

This case study presents the results of the recovery and analysis of three sets of disarticulated and incomplete human remains found in Ecuador, within the Amazonian jungle. Recovered body parts sustained extensive sharp force trauma situated on different aspect of the skeleton. The anthropological examination (bone reassembly, biological profile) was followed by a detailed analysis of cut marks, including a basic experimental study on pig bones to demonstrate that dismemberment may have occurred within a certain amount of time after death. Despite the location (deep into the Amazonian jungle) and the perpetrator's actions (dismemberment and dispersion of body parts in a river), forensic work both on the field and in laboratory allowed identification of the victims and the reconstruction of the sequence of events.

Biomass consumption and CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire

Treesearch

T.G. Soares Neto; J.A. Carvalho J.A.; C.A.G. Veras; E.C. Alvarado; R. Gielow; E.N. Lincoln; T.J. Christian; R.J. Yokelson; J.C. Santos

2009-01-01

Biomass consumption and C02, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48 percent and the estimated average moisture content...

Effects of Soil Texture on Belowground Carbon and Nutrient Storage in a Lowland Amazonian Forest Ecosystem.

Treesearch

Whendee L. Silver; Jason Neff; Megan McGroddy; Ed Veldkamp; Michael Keller; Raimundo Cosme

2000-01-01

Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian...

Ultrastructural and biochemical analysis of epidermal xanthophores and dermal chromatophores of the teleost Sparus aurata.

PubMed

Ferrer, C; Solano, F; Zuasti, A

1999-04-01

We have studied the pigmentary system of the teleost Sparus aurata skin by electron microscopy and chromatographic analysis. Under electron microscopy, we found the dermis to contain the three major types of recognized chromatophores: melanophores, xanthophores and iridophores. Melanophores were more abundant in the dorsal region, whereas the iridophores were more abundant in the ventral region. The most important discovery was that of epidermal xanthophores. Epidermal xanthophores were the only chromatophores in the epidermis, something only found in S aurata and in a teleost species living in the Antartic sea. In contrast, the biochemical analysis did not establish any special characteristics: we found pteridine and flavin pigments located mostly in the pigmented dorsal region. Riboflavin and pterin were two of the most abundant coloured pigment types, but other colourless pigments such as xanthopterin and isoxanthopterin were also detected.

Embryonic origin of the gnathostome vertebral skeleton

PubMed Central

Gillis, J. Andrew

2017-01-01

The vertebral column is a key component of the jawed vertebrate (gnathostome) body plan, but the primitive embryonic origin of this skeleton remains unclear. In tetrapods, all vertebral components (neural arches, haemal arches and centra) derive from paraxial mesoderm (somites). However, in teleost fishes, vertebrae have a dual embryonic origin, with arches derived from somites, but centra formed, in part, by secretion of bone matrix from the notochord. Here, we test the embryonic origin of the vertebral skeleton in a cartilaginous fish (the skate, Leucoraja erinacea) which serves as an outgroup to tetrapods and teleosts. We demonstrate, by cell lineage tracing, that both arches and centra are somite-derived. We find no evidence of cellular or matrix contribution from the notochord to the skate vertebral skeleton. These findings indicate that the earliest gnathostome vertebral skeleton was exclusively of somitic origin, with a notochord contribution arising secondarily in teleosts. PMID:29167367

Medicinal plants of the Achuar (Jivaro) of Amazonian Ecuador: ethnobotanical survey and comparison with other Amazonian pharmacopoeias.

PubMed

Giovannini, Peter

2015-04-22

This paper presents the first ethnobotanical survey conducted among the Achuar (Jivaro), indigenous people living in Amazonian Ecuador and Peru. The aims of this study are: (a) to present and discuss Achuar medicinal plant knowledge in the context of the epidemiology of this population (b) to compare the use of Achuar medicinal plants with the uses reported among the Shuar Jivaro and other Amazonian peoples. The author conducted field research in 9 indigenous villages in the region of Morona Santiago and Pastaza in Ecuador. Semi-structured interviews on local illnesses and herbal remedies were carried out with 82 informants and plant specimens were collected and later identified in Quito. A literature research was conducted on the medicinal species reported by Achuar people during this study. The most reported medicinal plants are species used by the Achuar to treat diarrhoea, parasites infection, fractures, wounds, and snakebites. Informants reported the use of 134 medicinal species for a total of 733 recorded use-reports. Of these 134 species, 44 are reported at least 3 times for one or more specific disease condition for a total of 56 uses. These species are considered a core kit of medicinal plants of the Achuar of Ecuador. Most of these medicinal species are widely used in the Amazon rainforest and in many other parts of Latin America. The author documented a core kit of 44 medicinal plants used among the Achuar of Ecuador and found that this core set of medicinal plants reflects local epidemiological concerns and the pharmacopoeias of the Shuar and other Amazonian groups. These findings suggest that inter-group diffusion of medicinal plant knowledge had a prominent role in the acquisition of current Achuar knowledge of medicinal plants. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Anthropogenic Land-use Change and the Dynamics of Amazon Forest Biomass

NASA Technical Reports Server (NTRS)

Laurance, William F.

2004-01-01

This project was focused on assessing the effects of prevailing land uses, such as habitat fragmentation, selective logging, and fire, on biomass and carbon storage in Amazonian forests, and on the dynamics of carbon sequestration in regenerating forests. Ancillary goals included developing GIs models to help predict the future condition of Amazonian forests, and assessing the effects of anthropogenic climate change and ENS0 droughts on intact and fragmented forests. Ground-based studies using networks of permanent plots were linked with remote-sensing data (including Landsat TM and AVHRR) at regional scales, and higher-resolution techniques (IKONOS imagery, videography, LIDAR, aerial photographs) at landscape and local scales. The project s specific goals were quite eclectic and included: Determining the effects of habitat fragmentation on forest dynamics, floristic composition, and the various components of above- and below-ground biomass. Assessing historical and physical factors that affect trajectories of forest regeneration and carbon sequestration on abandoned lands. Extrapolating results from local studies of biomass dynamics in fragmented and regenerating forests to landscape and regional scales in Amazonia, using remote sensing and GIS. Testing the hypothesis that intact Amazonian forests are functioning as a significant carbon sink. Examining destructive synergisms between forest fragmentation and fire. Assessing the short-term impacts of selective logging on aboveground biomass. Developing GIS models that integrate current spatial data on forest cover, deforestation, logging, mining, highway and roads, navigable rivers, vulnerability to wild fires, protected areas, and existing and planned infrastructure projects, in an effort to predict the future condition of Brazilian Amazonian forests over the next 20-25 years. Devising predictive spatial models to assess the influence of varied biophysical and anthropogenic predictors on Amazonian deforestation.

Did the martian outflow channels mostly form during the Amazonian Period?

NASA Astrophysics Data System (ADS)

Rodriguez, J. Alexis P.; Platz, Thomas; Gulick, Virginia; Baker, Victor R.; Fairén, Alberto G.; Kargel, Jeffrey; Yan, Jianguo; Miyamoto, Hideaki; Glines, Natalie

2015-09-01

Simud, Tiu, and Ares Valles comprise some of the largest outflow channels on Mars. Their excavation has been attributed variously to (or a combination of) erosion by catastrophic floods, glaciers, and debris flows. Numerous investigations indicate that they formed largely during the Late Hesperian (3.61-3.37 Ga). However, these studies mostly equate the ages of the outflow channel floors to those of the flows that generated mesoscale (several hundred meters to a few kilometers) bedforms within them. To improve the statistical accuracy in the age determinations of these flow events, we have used recently acquired high-resolution image and topographic data to map and date portions of Simud, Tiu and Ares Valles, which are extensively marked by these bedforms. Our results, which remove the statistical effects of older and younger outflow channel floor surfaces on the generation of modeled ages, reveal evidence for major outflow channel discharges occurring during the Early (3.37-1.23 Ga) and Middle (1.23-0.328 Ga) Amazonian, with activity significantly peaking during the Middle Amazonian stages. We also find that during the documented stages of Middle Amazonian discharges, the floor of Tiu Valles underwent widespread collapse, resulting in chaotic terrain formation. In addition, we present evidence showing that following the outflow channel discharges, collapse within northern Simud Valles generated another chaotic terrain. This younger chaos region likely represents the latest stage of large-scale outflow channel resurfacing within the study area. Our findings imply that in southern circum-Chryse the martian hydrosphere experienced large-scale drainage during the Amazonian, which likely led to periodic inundation and sedimentation within the northern plains.

Oxidative stress enzyme and histopathological lesions in Colossoma macropomum (pisces, ariidae) for environmental impact assessment

NASA Astrophysics Data System (ADS)

Andrade, Ticianne de Sousa de Oliveira Mota; Sousa, Debora Batista Pinheiro; Dantas, Janaina Gomes; Castro, Jonatas da Silva; Neta, Raimunda Nonata Fortes Carvalho

2015-12-01

This study used oxidative stress enzyme (Glutathione S-Transferase and Catalase), histopathological lesions (Branchial lesions) and biometric data in the freshwater fish tambaqui, Colossoma macropomum, to assess environmental impacts in an Environmental Protection Area at São Luis, Brazil. Fish were sampled from two locations (A1 = contaminated area and A2 = reference site) within the protected area on four occasions. The activity of catalase (CAT) and glutathione S-transferase (GST) in C. macropomum was compared with biometric data and histopathological lesions. Results have shown that biometric data decreased significantly in fish (p<0.05) at the contaminated site. The activity of CAT was higher in fish specifically caught in A1. A significant difference was observed in the GST activity in the liver of C. macropomum when comparing fish from the contaminated site and those from the reference site (p<0.05).

Rainforest metropolis casts 1,000-km defaunation shadow.

PubMed

Tregidgo, Daniel J; Barlow, Jos; Pompeu, Paulo S; de Almeida Rocha, Mayana; Parry, Luke

2017-08-08

Tropical rainforest regions are urbanizing rapidly, yet the role of emerging metropolises in driving wildlife overharvesting in forests and inland waters is unknown. We present evidence of a large defaunation shadow around a rainforest metropolis. Using interviews with 392 rural fishers, we show that fishing has severely depleted a large-bodied keystone fish species, tambaqui ( Colossoma macropomum ), with an impact extending over 1,000 km from the rainforest city of Manaus (population 2.1 million). There was strong evidence of defaunation within this area, including a 50% reduction in body size and catch rate (catch per unit effort). Our findings link these declines to city-based boats that provide rural fishers with reliable access to fish buyers and ice and likely impact rural fisher livelihoods and flooded forest biodiversity. This empirical evidence that urban markets can defaunate deep into rainforest wilderness has implications for other urbanizing socioecological systems.

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

Biomass consumption and CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire

Treesearch

T. G. Soares Neto; J. A. Carvalho; C. A. G. Veras; E. C. Alvarado; R. Gielow; E. N. Lincoln; T. J. Christian; R. J. Yokelson; J. C. Santos

2009-01-01

Biomass consumption and CO2, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48% and the estimated average moisture content of fresh biomass was 42% on...

Extremely long-distance seed dispersal by an overfished Amazonian frugivore.

PubMed

Anderson, Jill T; Nuttle, Tim; Saldaña Rojas, Joe S; Pendergast, Thomas H; Flecker, Alexander S

2011-11-22

Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337-552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700-2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants.

Extremely long-distance seed dispersal by an overfished Amazonian frugivore

PubMed Central

Anderson, Jill T.; Nuttle, Tim; Saldaña Rojas, Joe S.; Pendergast, Thomas H.; Flecker, Alexander S.

2011-01-01

Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum. During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma, and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337–552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700–2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants. PMID:21429923

Morphologically cryptic Amazonian bird species pairs exhibit strong postzygotic reproductive isolation.

PubMed

Pulido-Santacruz, Paola; Aleixo, Alexandre; Weir, Jason T

2018-03-14

We possess limited understanding of how speciation unfolds in the most species-rich region of the planet-the Amazon basin. Hybrid zones provide valuable information on the evolution of reproductive isolation, but few studies of Amazonian vertebrate hybrid zones have rigorously examined the genome-wide underpinnings of reproductive isolation. We used genome-wide genetic datasets to show that two deeply diverged, but morphologically cryptic sister species of forest understorey birds show little evidence for prezygotic reproductive isolation, but substantial postzygotic isolation. Patterns of heterozygosity and hybrid index revealed that hybrid classes with heavily recombined genomes are rare and closely match simulations with high levels of selection against hybrids. Genomic and geographical clines exhibit a remarkable similarity across loci in cline centres, and have exceptionally narrow cline widths, suggesting that postzygotic isolation is driven by genetic incompatibilities at many loci, rather than a few loci of strong effect. We propose Amazonian understorey forest birds speciate slowly via gradual accumulation of postzygotic genetic incompatibilities, with prezygotic barriers playing a less important role. Our results suggest old, cryptic Amazonian taxa classified as subspecies could have substantial postzygotic isolation deserving species recognition and that species richness is likely to be substantially underestimated in Amazonia. © 2018 The Author(s).

Geology and insolation-driven climatic history of Amazonian north polar materials on Mars

USGS Publications Warehouse

Tanaka, K.L.

2005-01-01

Mariner 9 and Viking spacecraft images revealed that the polar regions of Mars, like those of Earth, record the planet's climate history. However, fundamental uncertainties regarding the materials, features, ages and processes constituting the geologic record remained. Recently acquired Mars Orbiter Laser Altimeter data and Mars Orbiter Camera high-resolution images from the Mars Global Surveyor spacecraft and moderately high-resolution Thermal Emission Imaging System visible images from the Mars Odyssey spacecraft permit more comprehensive geologic and climatic analyses. Here I map and show the history of geologic materials and features in the north polar region that span the Amazonian period (???3.0 Gyr ago to present). Erosion and redeposition of putative circumpolar mud volcano deposits (formed by eruption of liquefied, fine-grained material) led to the formation of an Early Amazonian polar plateau consisting of dark layered materials. Crater ejecta superposed on pedestals indicate that a thin mantle was present during most of the Amazonian, suggesting generally higher obliquity and insolation conditions at the poles than at present. Brighter polar layered deposits rest unconformably on the dark layers and formed mainly during lower obliquity over the past 4-5 Myr (ref. 20). Finally, the uppermost layers post-date the latest downtrend in obliquity <20,000 years ago. ?? 2005 Nature Publishing Group.

Geology and insolation-driven climatic history of Amazonian north polar materials on Mars.

PubMed

Tanaka, Kenneth L

2005-10-13

Mariner 9 and Viking spacecraft images revealed that the polar regions of Mars, like those of Earth, record the planet's climate history. However, fundamental uncertainties regarding the materials, features, ages and processes constituting the geologic record remained. Recently acquired Mars Orbiter Laser Altimeter data and Mars Orbiter Camera high-resolution images from the Mars Global Surveyor spacecraft and moderately high-resolution Thermal Emission Imaging System visible images from the Mars Odyssey spacecraft permit more comprehensive geologic and climatic analyses. Here I map and show the history of geologic materials and features in the north polar region that span the Amazonian period (approximately 3.0 Gyr ago to present). Erosion and redeposition of putative circumpolar mud volcano deposits (formed by eruption of liquefied, fine-grained material) led to the formation of an Early Amazonian polar plateau consisting of dark layered materials. Crater ejecta superposed on pedestals indicate that a thin mantle was present during most of the Amazonian, suggesting generally higher obliquity and insolation conditions at the poles than at present. Brighter polar layered deposits rest unconformably on the dark layers and formed mainly during lower obliquity over the past 4-5 Myr (ref. 20). Finally, the uppermost layers post-date the latest downtrend in obliquity <20,000 years ago.

Multiple mechanisms of Amazonian forest biomass losses in three dynamic global vegetation models under climate change.

PubMed

Galbraith, David; Levy, Peter E; Sitch, Stephen; Huntingford, Chris; Cox, Peter; Williams, Mathew; Meir, Patrick

2010-08-01

*The large-scale loss of Amazonian rainforest under some future climate scenarios has generally been considered to be driven by increased drying over Amazonia predicted by some general circulation models (GCMs). However, the importance of rainfall relative to other drivers has never been formally examined. *Here, we conducted factorial simulations to ascertain the contributions of four environmental drivers (precipitation, temperature, humidity and CO(2)) to simulated changes in Amazonian vegetation carbon (C(veg)), in three dynamic global vegetation models (DGVMs) forced with climate data based on HadCM3 for four SRES scenarios. *Increased temperature was found to be more important than precipitation reduction in causing losses of Amazonian C(veg) in two DGVMs (Hyland and TRIFFID), and as important as precipitation reduction in a third DGVM (LPJ). Increases in plant respiration, direct declines in photosynthesis and increases in vapour pressure deficit (VPD) all contributed to reduce C(veg) under high temperature, but the contribution of each mechanism varied greatly across models. Rising CO(2) mitigated much of the climate-driven biomass losses in the models. *Additional work is required to constrain model behaviour with experimental data under conditions of high temperature and drought. Current models may be overly sensitive to long-term elevated temperatures as they do not account for physiological acclimation.

Osmoregulatory actions of the GH/IGF axis in non-salmonid teleosts

USGS Publications Warehouse

Mancera, J.M.; McCormick, S.D.

1998-01-01

Salmonid fishes provided the first findings on the influence of the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis on osmoregulation in teleost fishes. Recent studies on non-salmonid species, however, indicate that this physiological action of the GH/IGF-I axis is not restricted to salmonids or anadromous fishes. GH-producing cells in the pituitary of fish acclimated to different salinities show different degrees of activation depending on the species studied. Plasma GH levels either increase or do not change after transfer of fish from freshwater to seawater. Treatment with GH or IGF-I increases salinity tolerance and/or increases gill Na+,K+-ATPase activity of killifish (Fundulus heteroclitus), tilapia (Oreochromis mossambicus and Oreochromis niloticus) and striped bass (Morone saxatilis). As in salmonids, a positive interaction between GH and cortisol for improving hypoosmoregulatory capacity has been described in tilapia (O. mossambicus). Research on the osmoregulatory role of the GH/IGF-I axis is derived from a small number of teleost species. The study of more species with different osmoregulary patterns will be necessary to fully clarify the osmoregulatory role of GH/IGF-I axis in fish. The available data does suggest, however, that the influence of the GH/IGF-I axis on osmoregulation may be a common feature of euryhalinity in teleosts. Copyright (C) 1998 Elsevier Science Inc.

Exploring a Nonmodel Teleost Genome Through RAD Sequencing—Linkage Mapping in Common Pandora, Pagellus erythrinus and Comparative Genomic Analysis

PubMed Central

Manousaki, Tereza; Tsakogiannis, Alexandros; Taggart, John B.; Palaiokostas, Christos; Tsaparis, Dimitris; Lagnel, Jacques; Chatziplis, Dimitrios; Magoulas, Antonios; Papandroulakis, Nikos; Mylonas, Constantinos C.; Tsigenopoulos, Costas S.

2015-01-01

Common pandora (Pagellus erythrinus) is a benthopelagic marine fish belonging to the teleost family Sparidae, and a newly recruited species in Mediterranean aquaculture. The paucity of genetic information relating to sparids, despite their growing economic value for aquaculture, provides the impetus for exploring the genomics of this fish group. Genomic tool development, such as genetic linkage maps provision, lays the groundwork for linking genotype to phenotype, allowing fine-mapping of loci responsible for beneficial traits. In this study, we applied ddRAD methodology to identify polymorphic markers in a full-sib family of common pandora. Employing the Illumina MiSeq platform, we sampled and sequenced a size-selected genomic fraction of 99 individuals, which led to the identification of 920 polymorphic loci. Downstream mapping analysis resulted in the construction of 24 robust linkage groups, corresponding to the karyotype of the species. The common pandora linkage map showed varying degrees of conserved synteny with four other teleost genomes, namely the European seabass (Dicentrarchus labrax), Nile tilapia (Oreochromis niloticus), stickleback (Gasterosteus aculeatus), and medaka (Oryzias latipes), suggesting a conserved genomic evolution in Sparidae. Our work exploits the possibilities of genotyping by sequencing to gain novel insights into genome structure and evolution. Such information will boost the study of cultured species and will set the foundation for a deeper understanding of the complex evolutionary history of teleosts. PMID:26715088

Functional Significance of GnRH and Kisspeptin, and Their Cognate Receptors in Teleost Reproduction

PubMed Central

Gopurappilly, Renjitha; Ogawa, Satoshi; Parhar, Ishwar S.

2012-01-01

Guanine nucleotide binding protein (G-protein)-coupled receptors (GPCRs) are eukaryotic transmembrane proteins found in all living organisms. Their versatility and roles in several physiological processes make them the single largest family of drug targets. Comparative genomic studies using various model organisms have provided useful information about target receptors. The similarity of the genetic makeup of teleosts to that of humans and other vertebrates aligns with the study of GPCRs. Gonadotropin-releasing hormone (GnRH) represents a critical step in the reproductive process through its cognate GnRH receptors (GnRHRs). Kisspeptin (Kiss1) and its cognate GPCR, GPR54 (=kisspeptin receptor, Kiss-R), have recently been identified as a critical signaling system in the control of reproduction. The Kiss1/Kiss-R system regulates GnRH release, which is vital to pubertal development and vertebrate reproduction. This review highlights the physiological role of kisspeptin-Kiss-R signaling in the reproductive neuroendocrine axis in teleosts through the modulation of GnRH release. Moreover, we also review the recent developments in GnRHR and Kiss-R with respect to their structural variants, signaling mechanisms, ligand interactions, and functional significance. Finally, we discuss the recent progress in identifying many teleost GnRH-GnRHR and kisspeptin-Kiss-R systems and consider their physiological significance in the control of reproduction. PMID:23482509

FMRFamide-like immunoreactive neurons of the nervus terminalis of teleosts innervate both retina and pineal organ.

PubMed

Ekström, P; Honkanen, T; Ebbesson, S O

1988-09-13

The tetrapeptide FMRFamide (Phe-Met-Arg-Phe-NH2) was first isolated from molluscan ganglia. Subsequently, it has become clear that vertebrate brains also contain endogenous FMRFamide-like substances. In teleosts, the neurons of the nervus terminalis contain an FMRFamide-like substance, and provide a direct innervation to the retina (Proc. Natl. Acad. Sci. U.S.A., 81 [1984] 940-944). Here we report the presence of FMRFamide-immunoreactive axonal bundles in the pineal organ of Coho salmon and three-spined sticklebacks. The largest numbers of axons were observed proximal to the brain, in the pineal stalk, while the distal part of the pineal organ contained only few axons. No FMRFamide-like-immunoreactive (IR) cell bodies were observed in the pineal organ. In adult fish it was not possible to determine the origin of these axons, due to the large numbers of FMRFamide-like IR axons in the teleost brain. However, by following the development of FMRFamide-like IR neurons in the embryonic and larval stickleback brain, it was possible to conclude that, at least in newly hatched fish, FMRFamide-like IR axons that originate in the nucleus nervus terminalis reach the pineal organ. Thus, it seems there is a direct connection between a specialized part of the chemosensory system and both the retina and the pineal organ in teleost fish.

Feeding Relationships among Six Seagrass-associated Fishes in the Northeastern Gwangyang Bay, Southern Korea

NASA Astrophysics Data System (ADS)

Park, Joo Myun; Kwak, Seok Nam; Han, In-Seong

2018-03-01

We conducted dietary analyses of six seagrass-associated fish species inhabiting northeastern Gwangyang Bay, Korea. These six species consumed a variety of benthic invertebrates and teleosts, but their preferences for different food resources varied. Although all species consumed crustaceans, the contributions of different crustacean taxa differed among the species' diets. Caridean shrimps and crabs were a significant part of the Hexagrammos agrammus and H. otakii diets, respectively, while amphipods were consumed mainly by Sebastes inermis. Caridean shrimps and prawns were abundant within the Lateolabrax japonicas diet, but were not common prey resources for Pseudopleuronectes yokohamae or S. schlegelii. Polychaetes and ophiurids were ingested by P. yokohamae, and the former prey taxon also made moderate contributions to the diets of H. agrammus and L. japonicus. With the exception of P. yokohamae, the diets of all species included teleosts. Teleosts contributed the largest proportion of the S. schlegelii diet, followed by the S. inermis and L. japonicas diets; however, H. agrammus and H. otakii rarely consumed teleosts. Non-metric multidimensional scaling (nMDS) ordination plots and permutational analysis of variance (PERMANOVA) revealed the variation in dietary composition among species and the contributions of each prey taxon. These interspecific differences in diet increase the range of food resources available to these fishes, thereby reducing competition for resources within the fish community in this region.

Thyroid status alters gill ionic metabolism and chloride cell morphology as evidenced by scanning electron microscopy in a teleost Anabas testudineus (Bloch): short and long term in vivo study.

PubMed

Sreejith, P; Beyo, R S; Prasad, G; Sunny, F; Oommen, O V

2007-12-01

Gill is the main organ of osmotic regulation in teleosts and chloride cells are the sites of ion transport across gill epithelium. Thyroid hormones are implicated in the regulation of osmotic balance in teleosts also. Treatment with 6-propyl thiouracil (6-PTU) inhibited the membrane bound enzyme Na+K+ ATPase in the gill while triiodothyronine (T3) injection stimulated it in a short-term in vivo study in the teleost Anabas testudineus. Na+, K+ and Ca2+ ions were also decreased in the 6-PTU treated fish and the T3 treatment increased their concentrations in the gill lamellae. The gill morphology also changed according to the thyroid status in the long term study. 6-PTU treatment altered the typical serrated morphology of the gill lamellae, while the T3 treatment reversed it. T3 injection increased the density of pavement and chloride cells as evidenced by scanning electron microscopy. The results demonstrate that physiological status of the thyroid influences gill Na+ pump activity and chloride cell morphological changes. Further, the study suggests a regulatory role of T3 on gill ions (Na+, K+ and Ca2+), Na+K+ and Ca2+ ATPase activity and the different gill cell types in A. testudineus.

A teleost CD46 is involved in the regulation of complement activation and pathogen infection.

PubMed

Li, Mo-Fei; Sui, Zhi-Hai; Sun, Li

2017-11-03

In mammals, CD46 is involved in the inactivation of complement by factor I (FI). In teleost, study on the function of CD46 is very limited. In this study, we examined the immunological property of a CD46 molecule (CsCD46) from tongue sole, a teleost species with important economic value. We found that recombinant CsCD46 (rCsCD46) interacted with FI and inhibited complement activation in an FI-dependent manner. rCsCD46 also interacted with bacterial pathogens via a different mechanism to that responsible for the FI interaction, involving different rCsCD46 sites. Cellular study showed that CsCD46 was expressed on peripheral blood leukocytes (PBL) and protected the cells against the killing effect of complement. When the CsCD46 on PBL was blocked by antibody before incubation of the cells with bacterial pathogens, cellular infection was significantly reduced. Consistently, when tongue sole were infected with bacterial pathogens in the presence of rCsCD46, tissue dissemination and survival of the pathogens were significantly inhibited. These results provide the first evidence to indicate that CD46 in teleosts negatively regulates complement activation via FI and protects host cells from complement-induced damage, and that CD46 is required for optimal bacterial infection probably by serving as a receptor for the bacteria.

Evolution and Expression of Tissue Globins in Ray-Finned Fishes.

PubMed

Gallagher, Michael D; Macqueen, Daniel J

2017-01-01

The globin gene family encodes oxygen-binding hemeproteins conserved across the major branches of multicellular life. The origins and evolutionary histories of complete globin repertoires have been established for many vertebrates, but there remain major knowledge gaps for ray-finned fish. Therefore, we used phylogenetic, comparative genomic and gene expression analyses to discover and characterize canonical “non-blood” globin family members (i.e., myoglobin, cytoglobin, neuroglobin, globin-X, and globin-Y) across multiple ray-finned fish lineages, revealing novel gene duplicates (paralogs) conserved from whole genome duplication (WGD) and small-scale duplication events. Our key findings were that: (1) globin-X paralogs in teleosts have been retained from the teleost-specific WGD, (2) functional paralogs of cytoglobin, neuroglobin, and globin-X, but not myoglobin, have been conserved from the salmonid-specific WGD, (3) triplicate lineage-specific myoglobin paralogs are conserved in arowanas (Osteoglossiformes), which arose by tandem duplication and diverged under positive selection, (4) globin-Y is retained in multiple early branching fish lineages that diverged before teleosts, and (5) marked variation in tissue-specific expression of globin gene repertoires exists across ray-finned fish evolution, including several previously uncharacterized sites of expression. In this respect, our data provide an interesting link between myoglobin expression and the evolution of air breathing in teleosts. Together, our findings demonstrate great-unrecognized diversity in the repertoire and expression of nonblood globins that has arisen during ray-finned fish evolution.

Application of multi-dimensional discrimination diagrams and probability calculations to Paleoproterozoic acid rocks from Brazilian cratons and provinces to infer tectonic settings

NASA Astrophysics Data System (ADS)

Verma, Sanjeet K.; Oliveira, Elson P.

2013-08-01

In present work, we applied two sets of new multi-dimensional geochemical diagrams (Verma et al., 2013) obtained from linear discriminant analysis (LDA) of natural logarithm-transformed ratios of major elements and immobile major and trace elements in acid magmas to decipher plate tectonic settings and corresponding probability estimates for Paleoproterozoic rocks from Amazonian craton, São Francisco craton, São Luís craton, and Borborema province of Brazil. The robustness of LDA minimizes the effects of petrogenetic processes and maximizes the separation among the different tectonic groups. The probability based boundaries further provide a better objective statistical method in comparison to the commonly used subjective method of determining the boundaries by eye judgment. The use of readjusted major element data to 100% on an anhydrous basis from SINCLAS computer program, also helps to minimize the effects of post-emplacement compositional changes and analytical errors on these tectonic discrimination diagrams. Fifteen case studies of acid suites highlighted the application of these diagrams and probability calculations. The first case study on Jamon and Musa granites, Carajás area (Central Amazonian Province, Amazonian craton) shows a collision setting (previously thought anorogenic). A collision setting was clearly inferred for Bom Jardim granite, Xingú area (Central Amazonian Province, Amazonian craton) The third case study on Older São Jorge, Younger São Jorge and Maloquinha granites Tapajós area (Ventuari-Tapajós Province, Amazonian craton) indicated a within-plate setting (previously transitional between volcanic arc and within-plate). We also recognized a within-plate setting for the next three case studies on Aripuanã and Teles Pires granites (SW Amazonian craton), and Pitinga area granites (Mapuera Suite, NW Amazonian craton), which were all previously suggested to have been emplaced in post-collision to within-plate settings. The seventh case studies on Cassiterita-Tabuões, Ritápolis, São Tiago-Rezende Costa (south of São Francisco craton, Minas Gerais) showed a collision setting, which agrees fairly reasonably with a syn-collision tectonic setting indicated in the literature. A within-plate setting is suggested for the Serrinha magmatic suite, Mineiro belt (south of São Francisco craton, Minas Gerais), contrasting markedly with the arc setting suggested in the literature. The ninth case study on Rio Itapicuru granites and Rio Capim dacites (north of São Francisco craton, Serrinha block, Bahia) showed a continental arc setting. The tenth case study indicated within-plate setting for Rio dos Remédios volcanic rocks (São Francisco craton, Bahia), which is compatible with these rocks being the initial, rift-related igneous activity associated with the Chapada Diamantina cratonic cover. The eleventh, twelfth and thirteenth case studies on Bom Jesus-Areal granites, Rio Diamante-Rosilha dacite-rhyolite and Timbozal-Cantão granites (São Luís craton) showed continental arc, within-plate and collision settings, respectively. Finally, the last two case studies, fourteenth and fifteenth showed a collision setting for Caicó Complex and continental arc setting for Algodões (Borborema province).

The phylogenetic significance of colour patterns in marine teleost larvae

PubMed Central

Baldwin, Carole C

2013-01-01

Ichthyologists, natural-history artists, and tropical-fish aquarists have described, illustrated, or photographed colour patterns in adult marine fishes for centuries, but colour patterns in marine fish larvae have largely been neglected. Yet the pelagic larval stages of many marine fishes exhibit subtle to striking, ephemeral patterns of chromatophores that warrant investigation into their potential taxonomic and phylogenetic significance. Colour patterns in larvae of over 200 species of marine teleosts, primarily from the western Caribbean, were examined from digital colour photographs, and their potential utility in elucidating evolutionary relationships at various taxonomic levels was assessed. Larvae of relatively few basal marine teleosts exhibit erythrophores, xanthophores, or iridophores (i.e. nonmelanistic chromatophores), but one or more of those types of chromatophores are visible in larvae of many basal marine neoteleosts and nearly all marine percomorphs. Whether or not the presence of nonmelanistic chromatophores in pelagic marine larvae diagnoses any major teleost taxonomic group cannot be determined based on the preliminary survey conducted, but there is a trend toward increased colour from elopomorphs to percomorphs. Within percomorphs, patterns of nonmelanistic chromatophores may help resolve or contribute evidence to existing hypotheses of relationships at multiple levels of classification. Mugilid and some beloniform larvae share a unique ontogenetic transformation of colour pattern that lends support to the hypothesis of a close relationship between them. Larvae of some tetraodontiforms and lophiiforms are strikingly similar in having the trunk enclosed in an inflated sac covered with xanthophores, a character that may help resolve the relationships of these enigmatic taxa. Colour patterns in percomorph larvae also appear to diagnose certain groups at the interfamilial, familial, intergeneric, and generic levels. Slight differences in generic colour patterns, including whether the pattern comprises xanthophores or erythrophores, often distinguish species. The homology, ontogeny, and possible functional significance of colour patterns in larvae are discussed. Considerably more investigation of larval colour patterns in marine teleosts is needed to assess fully their value in phylogenetic reconstruction. PMID:24039297

Workplan for Catalyzing Collaboration with Amazonian Universities in the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)

NASA Technical Reports Server (NTRS)

Brown, I. Foster; Moreira, Adriana

1997-01-01

Success of the Large-Scale Biosphere-Atmospheric Experiment in Amazonia (LBA) program depends on several critical factors, the most important being the effective participation of Amazonian researchers and institutions. Without host-county counterparts, particularly in Amazonia, many important studies cannot he undertaken due either to lack of qualified persons or to legal constraints. No less important, the acceptance of the LBA program in Amazonia is also dependent on what LBA can do for improving the scientific expertise in Amazonia. Gaining the active investment of Amazonian scientists in a comprehensive research program is not a trivial task. Potential collaborators are few, particularly where much of the research was to be originally focused - the southern arc of Brazilian Amazonia. The mid-term goals of the LBA Committee on Training and Education are to increase the number of collaborators and to demonstrate that LBA will be of benefit to the region.

Carbon Dioxide Physiological Forcing Dominates Projected Eastern Amazonian Drying

NASA Astrophysics Data System (ADS)

Richardson, T. B.; Forster, P. M.; Andrews, T.; Boucher, O.; Faluvegi, G.; Fläschner, D.; Kasoar, M.; Kirkevâg, A.; Lamarque, J.-F.; Myhre, G.; Olivié, D.; Samset, B. H.; Shawki, D.; Shindell, D.; Takemura, T.; Voulgarakis, A.

2018-03-01

Future projections of east Amazonian precipitation indicate drying, but they are uncertain and poorly understood. In this study we analyze the Amazonian precipitation response to individual atmospheric forcings using a number of global climate models. Black carbon is found to drive reduced precipitation over the Amazon due to temperature-driven circulation changes, but the magnitude is uncertain. CO2 drives reductions in precipitation concentrated in the east, mainly due to a robustly negative, but highly variable in magnitude, fast response. We find that the physiological effect of CO2 on plant stomata is the dominant driver of the fast response due to reduced latent heating and also contributes to the large model spread. Using a simple model, we show that CO2 physiological effects dominate future multimodel mean precipitation projections over the Amazon. However, in individual models temperature-driven changes can be large, but due to little agreement, they largely cancel out in the model mean.

Nervous control of fish swimbladders.

PubMed

Nilsson, Stefan

2009-01-01

The swimbladder of teleost fish receives a rich and complex innervation by nerve fibres of the autonomic nervous system. While an understanding of the form and function of a non-adrenergic, non-cholinergic innervation is slowly emerging, the pattern of control by the "classical" cholinergic and adrenergic innervation is becoming relatively well understood. This short review describes the autonomic innervation patterns, and attempts to summarise the role of cholinergic and adrenergic pathways in the control of gas secretion and resorption in the teleost swimbladder.

Changes in Amazonian forest biomass, dynamics, and composition, 1980-2002

NASA Astrophysics Data System (ADS)

Phillips, Oliver L.; Higuchi, Niro; Vieira, Simone; Baker, Timothy R.; Chao, Kuo-Jung; Lewis, Simon L.

Long-term, on-the-ground monitoring of forest plots distributed across Amazonia provides a powerful means to quantify stocks and fluxes of biomass and biodiversity. Here we examine the evidence for concerted changes in the structure, dynamics, and functional composition of old-growth Amazonian forests over recent decades. Mature forests have, as a whole, gained biomass and undergone accelerated growth and dynamics, but questions remain as to the long-term persistence of these changes. Because forest growth on average exceeds mortality, intact Amazonian forests have been functioning as a carbon sink. We estimate a net biomass increase in trees ≥10 cm diameter of 0.62 ± 0.23 t C ha-1 a-1 through the late twentieth century. If representative of the wider forest landscape, this translates into a sink in South American old-growth forest of at least 0.49 ± 0.18 Pg C a-1. If other biomass and necromass components also increased proportionally, the estimated South American old-growth forest sink is 0.79 ± 0.29 Pg C a-1, before allowing for possible gains in soil carbon. If tropical forests elsewhere are behaving similarly, the old-growth biomass forest sink would be 1.60 ± 0.58 Pg C a-1. This bottom-up estimate of the carbon balance of tropical forests is preliminary, pending syntheses of detailed biometric studies across the other tropical continents. There is also some evidence for recent changes in the functional composition (biodiversity) of Amazonian forest, but the evidence is less comprehensive than that for changes in structure and dynamics. The most likely driver(s) of changes are recent increases in the supply of resources such as atmospheric carbon dioxide, which would increase net primary productivity, increasing tree growth and recruitment, and, in turn, mortality. In the future the growth response of remaining undisturbed Amazonian forests is likely to saturate, and there is a risk of these ecosystems transitioning from sink to source driven by higher respiration (temperature), higher mortality (drought), or compositional change (functional shifts toward lighterwooded plants). Even a modest switch from carbon sink to source for Amazonian forests would impact global climate, biodiversity, and human welfare, while the documented acceleration of tree growth and mortality may already be affecting the interactions of thousands of plant and millions of animal species.

Reduced Future Precipitation Makes Permanence of Amazonian Carbon Sinks Questionable

NASA Astrophysics Data System (ADS)

Arora, V.

2011-12-01

The tropical forests of the Amazon, considered as a tipping element in Earth's climate system, provide several ecosystem services including the maintenance of favourable regional climatic conditions in the region and storage of large amounts of carbon in their above- and below-ground pools. While it is nearly impossible, at present, to put a dollar value on these ecosystem services, the developed countries have started paying large sums of money to developing countries in the tropics to reduce deforestation. Norway recently committed up to $1 billion to the Amazon fund. The United Nations' Reducing Emissions from Deforestation and forest Degradation (REDD) program also financially supports national activities of 13 countries worldwide. The primary assumption inherent in paying for avoiding deforestation is that avoided land use change emissions contribute towards climate change mitigation. In addition, the standing forests that are spared deforestation contribute towards additional carbon sinks associated with the CO2 fertilization effect. Implicit in this reasoning is the understanding that the carbon sinks provided by avoided deforestation have some "permanence" associated with them, at least in the order of 50-100 years. Clearly, if "avoided deforestation" is essentially "delayed deforestation" then the benefits will not be long lasting. More importantly, changes in climate have the potential to adversely affect the permanence of carbon sinks, whether they are being paid for or not. This presentation will address the question of "permanence" by analyzing simulations of the second generation Canadian Earth system model (CanESM2) that are contributing results to the upcoming fifth Coupled Modeled Intercomparison Project (CMIP5). CanESM2 results for the future RCP 2.6, 4.5 and 8.5 scenarios show, that due to reduced future precipitation, the Amazonian region remains a net source of carbon over the 21st century in all scenarios. The carbon losses during the recent 2005 and 2010 droughts in the Amazonian region nearly wiped away the gains made during a decade indicating that the era of intact Amazonian forests acting as carbon sinks may be over. CanESM2 simulations imply that the future of the Amazonian region may look more like these drought years, suggesting that the future reduced precipitation over the region can indeed "tip over" the Amazonian forests.

Endocrine control of osmoregulation in teleost fish

USGS Publications Warehouse

McCormick, S.D.

2001-01-01

SYNOPSIS. As the primary link between environmental change and physiological response, the neuroendocrinesystem is a critical part of osmoregulatory adaptations. Cortisol has been viewpd as 'the' seawater-adapting hormone in fish and prolactin as 'the' fresh water adapting hormone. Recent evidence indicates that the growth hormone/insulin-like growth factor I axis is also important in seawater adaptation in several teleosts of widely differing evolutionary lineages. In salmonids, growth hormone acts in synergy with cortisol to increase seawater tolerance, at least partly through the upregulation of gill cortisol receptors. Cortisol under some conditions may promote ion uptake and interacts with prolactin during acclimation to fresh water. The osmoregulatory actions of growth hormone and prolactin are antagonistic. In some species, thyroid hormones support the action of growth hormone and cortisol in promoting seawater acclimation. Although a broad generalization that holds for all teleosts is unlikely, our current understanding indicates that growth hormone promotes acclimation to seawater, prolactin promotes acclimation to fresh water, and cortisol interacts with both of these hormones thus having a dual osmoregulatory function.

No evidence for the radiation time lag model after whole genome duplications in Teleostei

PubMed Central

Laurent, Sacha; Salamin, Nicolas

2017-01-01

The short and long term effects of polyploidization on the evolutionary fate of lineages is still unclear despite much interest. First recognized in land plants, it has become clear that polyploidization is widespread in eukaryotes, notably at the origin of vertebrates and teleost fishes. Many hypotheses have been proposed to link the species richness of lineages and whole genome duplications. For instance, the radiation time lag model suggests that paleopolyploidy would favour the apparition of new phenotypic traits, although the radiation of the lineage would not occur before a later dispersion event. Some results indicate that this model may be observed during land plant evolution. In this work, we test predictions of the radiation time lag model using both fossil data and molecular phylogenies in ancient and more recent teleost whole genome duplications. We fail to find any evidence of delayed increase of the species number after any of these events and conclude that paleopolyploidization still remains to be unambiguously linked to taxonomic diversity in teleosts. PMID:28426792

Ontogenetic dynamics of mercury accumulation in Northwest Atlantic sea lamprey (Petromyzon marinus)

USGS Publications Warehouse

Drevnick, P.E.; Horgan, M.J.; Oris, J.T.; Kynard, B.E.

2006-01-01

We examined the ontogenetic dynamics of mercury accumulation in sea lamprey (Petromyzon marinus) from the Connecticut River, USA. Mercury concentrations in eggs (mean 84 ng??g-1 wet weight) were lowest of all life stages and correlated to concentrations in females. There was a higher rate of maternal transfer of mercury to eggs compared with teleosts. Ammocoetes had high mercury concentrations for their trophic level (e.g., mean of age-4 ammocoetes 492 ng??g-1 wet weight). A further investigation of four streams showed that ammocoetes reflected the level of contamination in their nursery streams. Concentrations of mercury decreased during metamorphosis from ammocoete to adult. Mercury concentrations in adults ranged from 83 to 942 ng??g-1 wet weight and, unlike teleosts, showed no relation to sex, length, or weight. We provide evidence from stable isotope analyses that this high variability is due to feeding ecology. There are fundamental differences in mercury accumulation between sea lamprey and teleosts. ?? 2006 NRC Canada.

Biology of Bony Fish Macrophages

PubMed Central

Hodgkinson, Jordan W.; Grayfer, Leon; Belosevic, Miodrag

2015-01-01

Macrophages are found across all vertebrate species, reside in virtually all animal tissues, and play critical roles in host protection and homeostasis. Various mechanisms determine and regulate the highly plastic functional phenotypes of macrophages, including antimicrobial host defenses (pro-inflammatory, M1-type), and resolution and repair functions (anti-inflammatory/regulatory, M2-type). The study of inflammatory macrophages in immune defense of teleosts has garnered much attention, and antimicrobial mechanisms of these cells have been extensively studied in various fish models. Intriguingly, both similarities and differences have been documented for the regulation of lower vertebrate macrophage antimicrobial defenses, as compared to what has been described in mammals. Advances in our understanding of the teleost macrophage M2 phenotypes likewise suggest functional conservation through similar and distinct regulatory strategies, compared to their mammalian counterparts. In this review, we discuss the current understanding of the molecular mechanisms governing teleost macrophage functional heterogeneity, including monopoetic development, classical macrophage inflammatory and antimicrobial responses as well as alternative macrophage polarization towards tissues repair and resolution of inflammation. PMID:26633534

Biology of Bony Fish Macrophages.

PubMed

Hodgkinson, Jordan W; Grayfer, Leon; Belosevic, Miodrag

2015-11-30

Macrophages are found across all vertebrate species, reside in virtually all animal tissues, and play critical roles in host protection and homeostasis. Various mechanisms determine and regulate the highly plastic functional phenotypes of macrophages, including antimicrobial host defenses (pro-inflammatory, M1-type), and resolution and repair functions (anti-inflammatory/regulatory, M2-type). The study of inflammatory macrophages in immune defense of teleosts has garnered much attention, and antimicrobial mechanisms of these cells have been extensively studied in various fish models. Intriguingly, both similarities and differences have been documented for the regulation of lower vertebrate macrophage antimicrobial defenses, as compared to what has been described in mammals. Advances in our understanding of the teleost macrophage M2 phenotypes likewise suggest functional conservation through similar and distinct regulatory strategies, compared to their mammalian counterparts. In this review, we discuss the current understanding of the molecular mechanisms governing teleost macrophage functional heterogeneity, including monopoetic development, classical macrophage inflammatory and antimicrobial responses as well as alternative macrophage polarization towards tissues repair and resolution of inflammation.

Cradles and museums of Antarctic teleost biodiversity.

PubMed

Dornburg, Alex; Federman, Sarah; Lamb, April D; Jones, Christopher D; Near, Thomas J

2017-09-01

Isolated in one of the most extreme marine environments on Earth, teleost fish diversity in Antarctica's Southern Ocean is dominated by one lineage: the notothenioids. Throughout the past century, the long-term persistence of this unique marine fauna has become increasingly threatened by regional atmospheric and, to a lesser extent oceanic, warming. Developing an understanding of how historical temperature shifts have shaped source-sink dynamics for Antarctica's teleost lineages provides critical insight for predicting future demographic responses to climate change. We use a combination of phylogenetic and biogeographic modelling to show that high-latitude Antarctic nearshore habitats have been an evolutionary sink for notothenioid species diversity. Contrary to expectations from island biogeographic theory, lower latitude regions of the Southern Ocean that include the northern Antarctic Peninsula and peripheral island archipelagos act as source areas to continental diversity. These peripheral areas facilitate both the generation of new species and repeated colonization of nearshore Antarctic continental regions. Our results provide historical context to contemporary trends of global climate change that threaten to invert these evolutionary dynamics.

Neuroendocrinology of Sexual Plasticity in Teleost Fishes

PubMed Central

Godwin, John

2010-01-01

The study of sex differences has produced major insights into the organization of animal phenotypes and the regulatory mechanisms generating phenotypic variation from similar genetic templates. Teleost fishes display the greatest diversity of sexual expression among vertebrate animals. This diversity appears to arise from diversity in the timing of sex determination and less functional interdependence among the components of sexuality relative to tetrapod vertebrates. Teleost model systems therefore provide powerful models for understanding gonadal and non-gonadal influences on behavioral and physiological variation. This review addresses socially controlled sex change and alternate male phenotypes in fishes. These sexual patterns are informative natural experiments that illustrate how variation in conserved neuroendocrine pathways can give rise to a wide range of reproductive adaptations. Key regulatory factors underlying sex change and alternative male phenotypes that have been identified to date include steroid hormones and the neuropeptides GnRH and arginine vasotocin, but genomic approaches are now implicating a diversity of other influences as well. PMID:20176046

A NEW SPECIES OF Bolivar Zaldívar-Riverón et Rodríguez-Jiménez (BRACONIDAE, DORYCTINAE) FROM BRAZIL, WITH NEW RECORDS OF THE AMAZONIAN B. ecuadorensis Zaldívar-Riverón et López-Estrada.

PubMed

Nunes, Juliano Fiorelini; Penteado-Dias, Angelica Maria; Souza-Gadelha, Sian De; Zaldívar-Riverón, Alejandro

2016-05-06

A new species of the doryctine genus Bolivar (Braconidae), B. brasiliensis sp. nov., is described from the Atlantic coastal region in Brazil. New records and taxonomic notes of the Amazonian B. ecuadorensis Zaldívar-Riverón et López-Estrada are also provided.

Flank vents and graben as indicators of Late Amazonian volcanotectonic activity on Olympus Mons

NASA Astrophysics Data System (ADS)

Peters, S. I.; Christensen, P. R.

2017-03-01

Previous studies have focused on large-scale features on Olympus Mons, such as its flank terraces, the summit caldera complex, and the basal escarpment and aureole deposits. Here we identify and characterize previously unrecognized and unmapped small scale features to help further understand the volcanotectonic evolution of this enormous volcano. Using Context Camera, High Resolution Imaging Science Experiment, Thermal Emission Imaging System, High Resolution Stereo Camera Digital Terrain Model, and Mars Orbiter Laser Altimeter data, we identified and characterized the morphology and distribution of 60 flank vents and 84 grabens on Olympus Mons. We find that effusive eruptions have dominated volcanic activity on Olympus Mons in the Late Amazonian. Explosive eruptions were rare, implying volatile-poor magmas and/or a lack of magma-water interactions during the Late Amazonian. The distribution of flank vents suggests dike propagation of hundreds of kilometers and shallow magma storage. Small grabens, not previously observed in lower-resolution data, occur primarily on the lower flanks of Olympus Mons and indicate late-stage extensional tectonism. Based on superposition relationships, we have concluded two stages of development for Olympus Mons during the Late Amazonian: (1) primarily effusive resurfacing and formation of flank vents followed by (2) waning effusive volcanism and graben formation and/or reactivation. This developmental sequence resembles that proposed for Ascraeus Mons and other large Martian shields, suggesting a similar geologic evolution for these volcanoes.

Hair as a Biomarker of Long Term Mercury Exposure in Brazilian Amazon: A Systematic Review

PubMed Central

de Oliveira Lima, Marcelo

2018-01-01

Many studies have assessed mercury (Hg) exposure in the Amazonian population. This article performs a literature search of the studies that used hair as a biomarker of Hg exposure in the Brazilian Amazonian population. The search covered the period from 1996 to 2016 and included articles which matched the following criteria: (1) articles related to Hg exposure into Brazilian Amazon; (2) articles that used hair as a biomarker of Hg exposure; (3) articles that used analytical tools to measure the Hg content on hair and (4) articles that presented arithmetic mean and/or minimum and maximum values of Hg. 36 studies were selected. The findings show that most of the studies were performed along margins of important rivers, such as Negro, Tapajós and Madeira. All the population presented mean levels of Hg on hair above 6 µg g−1 and general population, adults, not determined and men presented levels of Hg on hair above 10 µg g−1. The results show that most of the studies were performed by Brazilian institutions/researchers and the majority was performed in the State of Pará. The present study identified that Amazonian population has long-term been exposed to Hg. In terms of future perspectives, this study suggests the implementation of a strategic plan for environmental health surveillance in the region in order to promote health and benefit Amazonian population. PMID:29534534

Scorpion envenoming in Morona Santiago, Amazonian Ecuador: Molecular phylogenetics confirms involvement of the Tityus obscurus group.

PubMed

Román, Juan P; García, Fernanda; Medina, Doris; Vásquez, Manolo; García, José; Graham, Matthew R; Romero-Alvarez, Daniel; Pardal, Pedro P de Oliveira; Ishikawa, Edna A Y; Borges, Adolfo

2018-02-01

Scorpion envenoming by species in the genus Tityus is hereby reported from rural locations in the Amazonian province of Morona Santiago, southeastern Ecuador. Twenty envenoming cases (18 patients under 15 years of age) including one death (a 4-year-old male) were recorded at the Macas General Hospital, Morona Santiago, between January 2015 and December 2016 from the counties of Taisha (n=17), Huamboyo (n=1), Palora (n=1), and Logroño (n=1). An additional fatality from 2014 (a 3-year-old female from Nayantza, Taisha county) is also reported. Leukocytosis and low serum potassium levels were detected in most patients. We observed a significant negative correlation between leukocytosis and hypokalemia. Scorpions involved in three accidents from Macuma, Taisha County, were identified as genetically related to Tityus obscurus from the Brazilian Amazonian region based on comparison of mitochondrial DNA sequences encoding cytochrome oxidase subunit I. These cases, along with previously reported envenoming from northern Manabí, reinforce the notion that scorpionism is a health hazard for children in Ecuador and emphasizes the need to supply effective antivenoms against local species, which are not currently available. The genetic affinity of the Ecuadorian specimens with T. obscurus may underlay toxinological, clinical, and venom antigenic relationships among Amazonian scorpions that deserves further exploration for designing therapeutic strategies to treat scorpionism in the region. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous detection of Plasmodium vivax dhfr, dhps, mdr1 and crt-o resistance-associated mutations in the Colombian Amazonian region.

PubMed

Cubides, Juan Ricardo; Camargo-Ayala, Paola Andrea; Niño, Carlos Hernando; Garzón-Ospina, Diego; Ortega-Ortegón, Anggie; Ospina-Cantillo, Estefany; Orduz-Durán, María Fernanda; Patarroyo, Manuel Elkin; Patarroyo, Manuel Alfonso

2018-03-27

Malaria continues being a public health problem worldwide. Plasmodium vivax is the species causing the largest number of cases of malaria in Asia and South America. Due to the lack of a completely effective anti-malarial vaccine, controlling this disease has been based on transmission vector management, rapid diagnosis and suitable treatment. However, parasite resistance to anti-malarial drugs has become a major yet-to-be-overcome challenge. This study was thus aimed at determining pvmdr1, pvdhfr, pvdhps and pvcrt-o gene mutations and haplotypes from field samples obtained from an endemic area in the Colombian Amazonian region. Fifty samples of parasite DNA infected by a single P. vivax strain from symptomatic patients from the Amazonas department in Colombia were analysed by PCR and the pvdhfr, pvdhps, pvmdr1 and pvcrt-o genes were sequenced. Diversity estimators were calculated from the sequences and the haplotypes circulating in the Colombian Amazonian region were obtained. pvdhfr, pvdhps, pvmdr1 and pvcrt-o genes in the Colombian Amazonian region are characterized by low genetic diversity. Some resistance-associated mutations were found circulating in this population. New variants are also being reported. A selective sweep signal was located in pvdhfr and pvmdr1 genes, suggesting that these mutations (or some of them) could be providing an adaptive advantage.

Medicinal knowledge and plant utilization in an Amazonian coastal community of Marudá, Pará State (Brazil).

PubMed

Coelho-Ferreira, Márlia

2009-10-29

It shows the local medicinal uses of biodiversity in Brazil's Amazonian littoral, promoting the value of folk knowledge, and its applicability in future studies. To demonstrate the importance of the knowledge of medicinal plants in the Amazonian coastal community of Marudá, located in Pará State, Brazil. Fieldwork was conducted between 1996 and 1998, using the methods of participant observation, semi-structured interviews and informal discussions to elicit information from community residents and plant specialists, in addition to collecting plant material. Community residents possess knowledge of 229 medicinal plants distributed in 81 botanical families and know how to manipulate them in a variety of ways, with special care taken to ensure that they are used in the safest and most efficient manner. Therapeutic indications for these plants include illness and disease recognized in the repertoire of Western medicine as well as ailments perceived from a local cultural perspective. Results from this study attest to informants' knowledge of medicinal flora and their ability and openness to integrate new species from diverse origins into their gamut of medicinal knowledge, including industrial therapeutic preparations and animal products. Local uses of biodiversity in Brazil's Amazonian littoral are also evinced, promoting the value of folk medicinal knowledge. Similarly, it mentions the potential of implementing local knowledge in Brazil's Unitary Health System.

Exploring a Nonmodel Teleost Genome Through RAD Sequencing-Linkage Mapping in Common Pandora, Pagellus erythrinus and Comparative Genomic Analysis.

PubMed

Manousaki, Tereza; Tsakogiannis, Alexandros; Taggart, John B; Palaiokostas, Christos; Tsaparis, Dimitris; Lagnel, Jacques; Chatziplis, Dimitrios; Magoulas, Antonios; Papandroulakis, Nikos; Mylonas, Constantinos C; Tsigenopoulos, Costas S

2015-12-29

Common pandora (Pagellus erythrinus) is a benthopelagic marine fish belonging to the teleost family Sparidae, and a newly recruited species in Mediterranean aquaculture. The paucity of genetic information relating to sparids, despite their growing economic value for aquaculture, provides the impetus for exploring the genomics of this fish group. Genomic tool development, such as genetic linkage maps provision, lays the groundwork for linking genotype to phenotype, allowing fine-mapping of loci responsible for beneficial traits. In this study, we applied ddRAD methodology to identify polymorphic markers in a full-sib family of common pandora. Employing the Illumina MiSeq platform, we sampled and sequenced a size-selected genomic fraction of 99 individuals, which led to the identification of 920 polymorphic loci. Downstream mapping analysis resulted in the construction of 24 robust linkage groups, corresponding to the karyotype of the species. The common pandora linkage map showed varying degrees of conserved synteny with four other teleost genomes, namely the European seabass (Dicentrarchus labrax), Nile tilapia (Oreochromis niloticus), stickleback (Gasterosteus aculeatus), and medaka (Oryzias latipes), suggesting a conserved genomic evolution in Sparidae. Our work exploits the possibilities of genotyping by sequencing to gain novel insights into genome structure and evolution. Such information will boost the study of cultured species and will set the foundation for a deeper understanding of the complex evolutionary history of teleosts. Copyright © 2016 Manousaki et al.

Prolactin and teleost ionocytes: new insights into cellular and molecular targets of prolactin in vertebrate epithelia

USGS Publications Warehouse

Breves, Jason P.; McCormick, Stephen D.; Karlstrom, Rolf O.

2014-01-01

The peptide hormone prolactin is a functionally versatile hormone produced by the vertebrate pituitary. Comparative studies over the last six decades have revealed that a conserved function for prolactin across vertebrates is the regulation of ion and water transport in a variety of tissues including those responsible for whole-organism ion homeostasis. In teleost fishes, prolactin was identified as the “freshwater-adapting hormone”, promoting ion-conserving and water-secreting processes by acting on the gill, kidney, gut and urinary bladder. In mammals, prolactin is known to regulate renal, intestinal, mammary and amniotic epithelia, with dysfunction linked to hypogonadism, infertility, and metabolic disorders. Until recently, our understanding of the cellular mechanisms of prolactin action in fishes has been hampered by a paucity of molecular tools to define and study ionocytes, specialized cells that control active ion transport across branchial and epidermal epithelia. Here we review work in teleost models indicating that prolactin regulates ion balance through action on ion transporters, tight-junction proteins, and water channels in ionocytes, and discuss recent advances in our understanding of ionocyte function in the genetically and embryonically accessible zebrafish (Danio rerio). Given the high degree of evolutionary conservation in endocrine and osmoregulatory systems, these studies in teleost models are contributing novel mechanistic insight into how prolactin participates in the development, function, and dysfunction of osmoregulatory systems across the vertebrate lineage.

Evolution and Expression of Tissue Globins in Ray-Finned Fishes

PubMed Central

Gallagher, Michael D.

2017-01-01

The globin gene family encodes oxygen-binding hemeproteins conserved across the major branches of multicellular life. The origins and evolutionary histories of complete globin repertoires have been established for many vertebrates, but there remain major knowledge gaps for ray-finned fish. Therefore, we used phylogenetic, comparative genomic and gene expression analyses to discover and characterize canonical “non-blood” globin family members (i.e., myoglobin, cytoglobin, neuroglobin, globin-X, and globin-Y) across multiple ray-finned fish lineages, revealing novel gene duplicates (paralogs) conserved from whole genome duplication (WGD) and small-scale duplication events. Our key findings were that: (1) globin-X paralogs in teleosts have been retained from the teleost-specific WGD, (2) functional paralogs of cytoglobin, neuroglobin, and globin-X, but not myoglobin, have been conserved from the salmonid-specific WGD, (3) triplicate lineage-specific myoglobin paralogs are conserved in arowanas (Osteoglossiformes), which arose by tandem duplication and diverged under positive selection, (4) globin-Y is retained in multiple early branching fish lineages that diverged before teleosts, and (5) marked variation in tissue-specific expression of globin gene repertoires exists across ray-finned fish evolution, including several previously uncharacterized sites of expression. In this respect, our data provide an interesting link between myoglobin expression and the evolution of air breathing in teleosts. Together, our findings demonstrate great-unrecognized diversity in the repertoire and expression of nonblood globins that has arisen during ray-finned fish evolution. PMID:28173090

Life-history correlates of extinction risk and recovery potential.

PubMed

Hutchings, Jeffrey A; Myers, Ransom A; García, Verónica B; Lucifora, Luis O; Kuparinen, Anna

2012-06-01

Extinction risk is inversely associated with maximum per capita population growth rate (r(max)). However, this parameter is not known for most threatened species, underscoring the value in identifying correlates of r(max) that, in the absence of demographic data, would indirectly allow one to identify species and populations at elevated risk of extinction and their associated recovery potential. We undertook a comparative life-history analysis of 199 species from three taxonomic classes: Chondrichthyes (e.g., sharks; n = 82), Actinopterygii (teleost or bony fishes; n = 47), and Mammalia (n = 70, including 16 marine species). Median r(max) was highest for (and similar between) terrestrial mammals (0.71) and teleosts (0.43), significantly lower among chondrichthyans (0.26), and lower still in marine mammals (0.07). Age at maturity was the primary (and negative) correlate of r(max). In contrast, although body size was negatively correlated with r(max) in chondrichthyans and mammals, evidence of an association in teleosts was equivocal, and fecundity was not related to r(max) in fishes, despite recurring assertions to the contrary. Our analyses suggest that age at maturity can serve as a universal predictor of extinction risk in fishes and mammals when r(max) itself is unknown. Moreover, in contrast to what is generally expected, the recovery potential of teleost fishes does not differ from that of terrestrial mammals. Our findings are supportive of the application of extinction-risk criteria that are based on generation time and that are independent of taxonomic affinity.

A crisis in the making: responses of Amazonian forests to land use and climate change.

PubMed

Laurance, W F

1998-10-01

At least three global-change phenomena are having major impacts on Amazonian forests: (1) accelerating deforestation and logging; (2) rapidly changing patterns of forest loss; and (3) interactions between human land-use and climatic variability. Additional alterations caused by climatic change, rising concentrations of atmospheric carbon dioxide, mining, overhunting and other large-scale phenomena could also have important effects on the Amazon ecosystem. Consequently, decisions regarding Amazon forest use in the next decade are crucial to its future existence.

Tectonics of some Amazonian greenstone belts

NASA Technical Reports Server (NTRS)

Gibbs, A. K.

1986-01-01

Greenstone belts exposed amid gneisses, granitoid rocks, and less abundant granulites along the northern and eastern margins of the Amazonian Craton yield Trans-Amazonican metamorphic ages of 2.0-2.1 Ga. Early proterozoic belts in the northern region probably originated as ensimatic island arc complexes. The Archean Carajas belt in the southeastern craton probably formed in an extensional basin on older continental basement. That basement contains older Archean belts with pillow basalts and komatiites. Belts of ultramafic rocks warrant investigatijon as possible ophiolites. A discussion follows.

Applications of satellite image processing to the analysis of Amazonian cultural ecology

NASA Technical Reports Server (NTRS)

Behrens, Clifford A.

1991-01-01

This paper examines the application of satellite image processing towards identifying and comparing resource exploitation among indigenous Amazonian peoples. The use of statistical and heuristic procedures for developing land cover/land use classifications from Thematic Mapper satellite imagery will be discussed along with actual results from studies of relatively small (100 - 200 people) settlements. Preliminary research indicates that analysis of satellite imagery holds great potential for measuring agricultural intensification, comparing rates of tropical deforestation, and detecting changes in resource utilization patterns over time.

Hyperdominance in Amazonian forest carbon cycling

PubMed Central

Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C.A.; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C.; Laurance, Susan G.W.; Laurance, William F.; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W.; Ruokolainen, Kalle; Silveira, Marcos; Aymard C., Gerardo A.; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S.; Salomão, Rafael P.; Comiskey, James A.; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J.; Killeen, Timothy J.; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G.A.; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R.C.; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N. Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A.; Almeida, Everton C.; Davila, Esteban Álvarez; Aragão, Luiz E.O.C.; Erwin, Terry L.; Morandi, Paulo S.; de Oliveira, Edmar Almeida; Valadão, Marco B.X.; Zagt, Roderick J.; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J.; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E.; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C. Pallqui; Umetsu, Ricardo K.; de Camargo, Plínio Barbosa; Burnham, Robyn J.; Herrera, Rafael; Quesada, Carlos A.; Stropp, Juliana; Vieira, Simone A.; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L.; Pickavance, Georgia C.; Phillips, Oliver L.

2015-01-01

While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region. PMID:25919449

Hyperdominance in Amazonian forest carbon cycling.

PubMed

Fauset, Sophie; Johnson, Michelle O; Gloor, Manuel; Baker, Timothy R; Monteagudo M, Abel; Brienen, Roel J W; Feldpausch, Ted R; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C A; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C; Laurance, Susan G W; Laurance, William F; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W; Ruokolainen, Kalle; Silveira, Marcos; Aymard C, Gerardo A; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S; Salomão, Rafael P; Comiskey, James A; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J; Killeen, Timothy J; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G A; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R C; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A; Almeida, Everton C; Davila, Esteban Álvarez; Aragão, Luiz E O C; Erwin, Terry L; Morandi, Paulo S; de Oliveira, Edmar Almeida; Valadão, Marco B X; Zagt, Roderick J; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C Pallqui; Umetsu, Ricardo K; de Camargo, Plínio Barbosa; Burnham, Robyn J; Herrera, Rafael; Quesada, Carlos A; Stropp, Juliana; Vieira, Simone A; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L; Pickavance, Georgia C; Phillips, Oliver L

2015-04-28

While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few 'hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region.

Fish genomes provide novel insights into the evolution of vertebrate secretin receptors and their ligand.

PubMed

Cardoso, João C R; Félix, Rute C; Trindade, Marlene; Power, Deborah M

2014-12-01

The secretin receptor (SCTR) is a member of Class 2 subfamily B1 GPCRs and part of the PAC1/VPAC receptor subfamily. This receptor has long been known in mammals but has only recently been identified in other vertebrates including teleosts, from which it was previously considered to be absent. The ligand for SCTR in mammals is secretin (SCT), an important gastrointestinal peptide, which in teleosts has not yet been isolated, or the gene identified. This study revises the evolutionary model previously proposed for the secretin-GPCRs in metazoan by analysing in detail the fishes, the most successful of the extant vertebrates. All the Actinopterygii genomes analysed and the Chondrichthyes and Sarcopterygii fish possess a SCTR gene that shares conserved sequence, structure and synteny with the tetrapod homologue. Phylogenetic clustering and gene environment comparisons revealed that fish and tetrapod SCTR shared a common origin and diverged early from the PAC1/VPAC subfamily group. In teleosts SCTR duplicated as a result of the fish specific whole genome duplication but in all the teleost genomes analysed, with the exception of tilapia (Oreochromis niloticus), one of the duplicates was lost. The function of SCTR in teleosts is unknown but quantitative PCR revealed that in both sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) transcript abundance is high in the gastrointestinal tract suggesting it may intervene in similar processes to those in mammals. In contrast, no gene encoding the ligand SCT was identified in the ray-finned fishes (Actinopterygii) although it was present in the coelacanth (lobe finned fish, Sarcopterygii) and in the elephant shark (holocephalian). The genes in linkage with SCT in tetrapods and coelacanth were also identified in ray-finned fishes supporting the idea that it was lost from their genome. At present SCTR remains an orphan receptor in ray-finned fishes and it will be of interest in the future to establish why SCT was lost and which ligand substitutes for it so that full characterization of the receptor can occur. Copyright © 2014 Elsevier Inc. All rights reserved.

Phylogenetic insights into the diversity of homocytous cyanobacteria from Amazonian rivers.

PubMed

Genuário, Diego Bonaldo; Vaz, Marcelo Gomes Marçal Vieira; Melo, Itamar Soares de

2017-11-01

The Amazon Rainforest holds great tropical biodiversity, mainly because of its favourable climatic conditions. The high temperatures, luminosity and humidity coupled with the nutritional simplicity of cyanobacteria allow undiscovered diversity to flourish within this group of microorganisms. Some efforts to reveal this diversity have been attempted; however, most were focused on the microscopic observation of environmental samples without any genetic information. Very few studies focusing on morphological, ecological and molecular criteria have been conducted, and none have been devoted to homocytous cyanobacteria forms in Amazonia region. Therefore, the genetic relationships amongst strains retrieved from this ecosystem with regard to other environments from Brazil and the world have not been tested and, consequently, the Amazonian strains would naturally be assumed as novel to science. To examine these relationships, cultured homocytous cyanobacteria isolated from two Amazonian rivers (Amazonas and Solimões) were evaluated using a phylogenetic perspective, considering the 16S rRNA gene sequence. A total of eleven homocytous cyanobacterial strains were isolated. Morphologically, they were identified as Pseudanabaena, Leptolyngbya, Planktothrix and Phormidium, but genetically they were included in the typical clusters of Planktothrix, Pseudanabaena, Cephalothrix, Pantanalinema and Alkalinema. These three latter genera have been detected in other Brazilian ecosystems only (Pantanal, Atlantic Rainforest and Pampa), while those remaining have been extensively found in many parts of the world. The data provided here indicate that Amazonian rivers support a homocytous cyanobacterial diversity previously reported from other geographical and ecological environments. Copyright © 2017 Elsevier Inc. All rights reserved.

Connecting Amazonian, Cerrado, and Atlantic Forest histories: Paraphyly, old divergences, and modern population dynamics in tyrant-manakins (Neopelma/Tyranneutes, Aves: Pipridae).

PubMed

Capurucho, João Marcos Guimarães; Ashley, Mary V; Ribas, Camila C; Bates, John M

2018-06-11

Several biogeographic hypotheses have been proposed to explain connections between Amazonian and Atlantic forest biotas. These hypotheses are related to the timing of the connections and their geographic patterns. We performed a phylogeographic investigation of Tyrant-manakins (Aves: Pipridae, Neopelma/Tyranneutes) which include species inhabiting the Amazon and Atlantic forests, as well as gallery forests of the Cerrado. Using DNA sequence data, we determined phylogenetic relationships, temporal and geographic patterns of diversification, and recent intraspecific population genetic patterns, relative to the history of these biomes. We found Neopelma to be a paraphyletic genus, as N. chrysolophum is sister to Neopelma + Tyranneutes, with an estimated divergence of approximately 18 Myrs BP, within the oldest estimated divergence times of other Amazonian and Atlantic forest avian taxa. Subsequent divergences in the group occurred from Mid Miocene to Early Pliocene and involved mainly the Amazonian species, with an expansion into and subsequent speciation in the Cerrado gallery forests by N. pallescens. We found additional structure within N. chrysocephalum and N. sulphureiventer. Analysis of recent population dynamics in N. chrysocephalum, N. sulphureiventer, and N. pallescens revealed recent demographic fluctuations and restrictions to gene flow related to environmental changes since the last glacial cycle. No genetic structure was detected across the Amazon River in N. pallescens. The tyrant-manakins represent an old historical connection between the Amazon and Atlantic Forest. Copyright © 2018. Published by Elsevier Inc.

Chemokines in teleost fish species.

PubMed

Alejo, Alí; Tafalla, Carolina

2011-12-01

Chemokines are chemoattractant cytokines defined by the presence of four conserved cysteine residues which in mammals can be divided into four subfamilies depending on the arrangement of the first two conserved cysteines in their sequence: CXC (α), CC (β), C and CX(3)C classes. Evolutionarily, fish can be considered as an intermediate step between species which possess only innate immunity (invertebrates) and species with a fully developed acquired immune network such as mammals. Therefore, the functionality of their different immune cell types and molecules is sometimes also intermediate between innate and acquired responses. The first chemokine gene identified in a teleost was a rainbow trout (Oncorhynchus mykiss) chemokine designated as CK1 in 1998. Since then, many different chemokine genes have been identified in several fish species, but their role in homeostasis and immune response remains largely unknown. Extensive genomic duplication events and the fact that chemokines evolve more quickly than other immune genes, make it very difficult to establish true orthologues between fish and mammalian chemokines that would help us with the ascription of immune roles. In this review, we describe the current state of knowledge of chemokine biology in teleost fish, focusing mainly on which genes have been identified so far and highlighting the most important aspects of their expression regulation, due to the great lack of functional information available for them. As the number of chemokine genes begins to close down for some teleost species, there is an important need for functional assays that may elucidate the role of each of these molecules within the fish immune response. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparative feeding ecology of bull sharks (Carcharhinus leucas) in the coastal waters of the southwest Indian Ocean inferred from stable isotope analysis.

PubMed

Daly, Ryan; Froneman, Pierre W; Smale, Malcolm J

2013-01-01

As apex predators, sharks play an important role shaping their respective marine communities through predation and associated risk effects. Understanding the predatory dynamics of sharks within communities is, therefore, necessary to establish effective ecologically based conservation strategies. We employed non-lethal sampling methods to investigate the feeding ecology of bull sharks (Carcharhinus leucas) using stable isotope analysis within a subtropical marine community in the southwest Indian Ocean. The main objectives of this study were to investigate and compare the predatory role that sub-adult and adult bull sharks play within a top predatory teleost fish community. Bull sharks had significantly broader niche widths compared to top predatory teleost assemblages with a wide and relatively enriched range of δ(13)C values relative to the local marine community. This suggests that bull sharks forage from a more diverse range of δ(13)C sources over a wider geographical range than the predatory teleost community. Adult bull sharks appeared to exhibit a shift towards consistently higher trophic level prey from an expanded foraging range compared to sub-adults, possibly due to increased mobility linked with size. Although predatory teleost fish are also capable of substantial migrations, bull sharks may have the ability to exploit a more diverse range of habitats and appeared to prey on a wider diversity of larger prey. This suggests that bull sharks play an important predatory role within their respective marine communities and adult sharks in particular may shape and link ecological processes of a variety of marine communities over a broad range.

Teleost fish models in membrane transport research: the PEPT1(SLC15A1) H+–oligopeptide transporter as a case study

PubMed Central

Romano, Alessandro; Barca, Amilcare; Storelli, Carlo; Verri, Tiziano

2014-01-01

Human genes for passive, ion-coupled transporters and exchangers are included in the so-called solute carrier (SLC) gene series, to date consisting of 52 families and 398 genes. Teleost fish genes for SLC proteins have also been described in the last two decades, and catalogued in preliminary SLC-like form in 50 families and at least 338 genes after systematic GenBank database mining (December 2010–March 2011). When the kinetic properties of the expressed proteins are studied in detail, teleost fish SLC transporters always reveal extraordinary ‘molecular diversity’ with respect to the mammalian counterparts, which reflects peculiar adaptation of the protein to the physiology of the species and/or to the environment where the species lives. In the case of the H+–oligopeptide transporter PEPT1(SLC15A1), comparative analysis of diverse teleost fish orthologs has shown that the protein may exhibit very eccentric properties in terms of pH dependence (e.g. the adaptation of zebrafish PEPT1 to alkaline pH), temperature dependence (e.g. the adaptation of icefish PEPT1 to sub-zero temperatures) and/or substrate specificity (e.g. the species-specificity of PEPT1 for the uptake of l-lysine-containing peptides). The revelation of such peculiarities is providing new contributions to the discussion on PEPT1 in both basic (e.g. molecular structure–function analyses) and applied research (e.g. optimizing diets to enhance growth of commercially valuable fish). PMID:23981715

Transcriptome analysis of vertebral bone in the flounder, Paralichthys olivaceus (Teleostei, Pleuronectiformes), using Illumina sequencing.

PubMed

Ibaraki, Harumi; Wu, Xiaoming; Uji, Susumu; Yokoi, Hayato; Sakai, Yoshifumi; Suzuki, Tohru

2015-12-01

The processes underlying vertebral development in teleosts and tetrapods differ markedly in a variety of ways. At present, the molecular basis of teleost vertebral development and growth is poorly understood. Understanding vertebral development at the molecular level is important for aquaculture to prevent vertebral anomalies that can arise from a variety of factors, including excess vitamin A (all-trans retinol, VA) in the diet. To facilitate studies on teloest vertebral development, we performed transcriptome analysis of four month old flounder, Paralichthys olivaceus, vertebrae using next-generation sequencing. Expression profile obtained demonstrates that some members of the hh, bmp, fgf, wnt gene families, and their receptors, hox, pax, sox, dlx and tbx gene families and ntl, which are known to function in notochord and somite development in embryos, are expressed in the vertebrae. It was also showed that in addition to the retinoic acid receptor (Rar), the vertebrae express alcohol dehydrogenase 1 and retinal dehydrogenase 2 which convert VA to all-trans-retinoic acid (RA). The assembled contigs also included cytochrome p450 family members, which inactivate RA, as well as phosphatidylcholine-retinol O-acetyltransferase, which converts VA to all-trans-retinyl ester, a stock form of VA. These data suggest that in teleost vertebrae, expression of various signals and transcription factors which function in the notochord and somite development is maintained until adult stage, and RA metabolism and signaling are active to regulate transcription of RA-responsible genes, such as hedgehog and hox genes. This is the first transcriptome analysis of teleost fish vertebrae. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparative Feeding Ecology of Bull Sharks (Carcharhinus leucas) in the Coastal Waters of the Southwest Indian Ocean Inferred from Stable Isotope Analysis

PubMed Central

Daly, Ryan; Froneman, Pierre W.; Smale, Malcolm J.

2013-01-01

As apex predators, sharks play an important role shaping their respective marine communities through predation and associated risk effects. Understanding the predatory dynamics of sharks within communities is, therefore, necessary to establish effective ecologically based conservation strategies. We employed non-lethal sampling methods to investigate the feeding ecology of bull sharks (Carcharhinus leucas) using stable isotope analysis within a subtropical marine community in the southwest Indian Ocean. The main objectives of this study were to investigate and compare the predatory role that sub-adult and adult bull sharks play within a top predatory teleost fish community. Bull sharks had significantly broader niche widths compared to top predatory teleost assemblages with a wide and relatively enriched range of δ13C values relative to the local marine community. This suggests that bull sharks forage from a more diverse range of δ13C sources over a wider geographical range than the predatory teleost community. Adult bull sharks appeared to exhibit a shift towards consistently higher trophic level prey from an expanded foraging range compared to sub-adults, possibly due to increased mobility linked with size. Although predatory teleost fish are also capable of substantial migrations, bull sharks may have the ability to exploit a more diverse range of habitats and appeared to prey on a wider diversity of larger prey. This suggests that bull sharks play an important predatory role within their respective marine communities and adult sharks in particular may shape and link ecological processes of a variety of marine communities over a broad range. PMID:24205168

Artificial fertilization by intracytoplasmic sperm injection in a teleost fish, the medaka (Oryzias latipes).

PubMed

Otani, Satoshi; Iwai, Toshiharu; Nakahata, Shingo; Sakai, Chiharu; Yamashita, Masakane

2009-01-01

Intracytoplasmic sperm injection (ICSI) is a technique that has been successfully used for assisting reproduction in mammals. However, this method is still not reliable in nonmammalian species, including teleosts. We succeeded in producing medaka individuals by ICSI with a rate of 13.4% (28 hatched embryos out of 209 eggs fertilized by ICSI), the best value reported so far in teleosts, including zebrafish and Nile tilapia. Although the technique was based on that developed for mammalian eggs, some critical modifications were made to adjust it to the medaka egg, which has a thick and hard envelope (the chorion) and a single sperm entry site (the micropyle). Medaka ICSI was performed by injecting a demembranated spermatozoon into an egg cytoplasm through the micropyle 10-15 sec after egg activation induced by a piezo-actuated vibration, the site and timing of sperm penetration being consistent with those in normal fertilization in medaka. To increase the efficiency of ICSI in medaka, we found that the fertilization by ICSI should precisely mimic the fertilization by insemination with intact sperm, both spatially and temporally. The success rate of ICSI was highly variable in batches of eggs (ranging from 0% to 56%), suggesting that the conditions of eggs are important factors in stabilizing the production of individuals by ICSI. The success in medaka ICSI provides a basis for future research to understand the basic mechanisms in gamete biology of teleosts as well as for development of new technology that can yield valuable applications in fisheries science.

Metabolic-morphologic characteristics of the integument of teleost fish with mature lymphocystis nodules.

PubMed

Spitzer, R H; Koch, E A; Reid, R B; Downing, S W

1982-01-01

Normal and virus-infected (lymphocystis disease) integument from five species of teleosts was examined by light and TEM autoradiography and SEM to establish metabolic-morphologic characteristics of integument with mature lymphocystis cells (LC's). LC's with numerous morphologic attributes of a late developmental stage showed highest incorporation of [3H]-thymidine in vivo (1-91 h) above the intracytoplasmic inclusion body (ci) with little radiolabel in nuclei, cytoplasmic icosahedral deoxyriboviruses (ICDV's) or capsule. Analysis by quantitative autoradiography revealed that the % total cell label in ci and cytoplasm did not vary appreciably from 1-91 h and was corroborative with morphologic criteria of maturity. A possibly phylogenetic difference was noted between teleosts, wherein normal integument showed uptake of [3H]-thymidine in vivo (1 h) by cells at all levels of the epidermis, and cyclostomes (Spitzer et al. 1979) wherein labeling was confined to the basal third of the epidermis. Among four infected teleost species, the mean diameters of the ICDV's measured under the same conditions, ranged from 259.5 nm to 290.0 nm with the mean for each species differing significantly (p less than 0.01) from each of the other means. Ruptured LC's were shown by TEM and SEM to have released ICDV's onto the lesions and integument. Various stages of LC degeneration, host response, and integumental repair processes were documented. An evaluation of labeling in vivo of the capsular matrix was compatible ([3H]-D-galactose greater than [3H]-L-lysine much greater than [3H]-L-fucose) with a glycosaminoglycan-protein structure.

Cloning of a growth hormone from a primitive bony fish and its phylogenetic relationships.

PubMed

Rubin, D A; Dores, R M

1994-07-01

Growth hormone (GH), prolactin, and their relatives constitute a multigene family which is considered to have evolved from a common ancestor. The structural and functional domains of GH appear to be highly conserved among vertebrates. In order to investigate the phylogenetic relationships among GHs in the Actinopterygii and Sarcopterygii, we have cloned and sequenced GH from the pituitary of the primitive bony fish, Amia calva. Bony fishes (teleosts) and Amia (Halecomorphi) are purported sister-groups within the Neoptergii, hence studies on this perspective group of fish can provide insights into the evolution of GH. The deduced amino acid (aa) sequence from A. calva GH (amGH) cDNA revealed that the mature GH consists of 190 residues. Phylogenetic comparisons with GH aa sequences from blue shark, sturgeon, four teleosts (eel, carp, porgy, flounder), and two sarcopterygians (African lungfish and bullfrog) indicated, in the most parsimonious cladogram, that amGH clusters as the sister-group to the teleosts, that sturgeon is the sister-group to the Neopterygii, and that the African lungfish and bullfrog are in the same clade.

The Origin And Migration Of Primordial Germ Cells In Sturgeons

PubMed Central

Saito, Taiju; Pšenička, Martin; Goto, Rie; Adachi, Shinji; Inoue, Kunio; Arai, Katsutoshi; Yamaha, Etsuro

2014-01-01

Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts. PMID:24505272

Vasotocinergic control of agonistic behavior told by Neotropical fishes.

PubMed

Silva, Ana C; Pandolfi, Matías

2018-04-24

The hypothalamic neuropeptides of the vasopressin-oxytocin family (and their homologs for non-mammalian species) are key modulators of the Social Brain Network, acting via specific receptors reported in all the nuclei of this network. Different conclusive examples have proven the context-dependency actions of hypothalamic nonapeptides on social behavior in several vertebrate taxa. Teleost fishes provide endless possibilities of experimental model systems to explore the underlying mechanisms of nonapeptide actions on social behavior given that they are the most diverse group of vertebrates. Although it has been difficult to identify commonalities of nonapeptide actions across species, indisputable evidence in many teleost species have demonstrated a clear role of vasotocin in the modulation of aggressive and sexual behaviors. Though Neotropical South American fish contribute an important percentage of teleost diversity, most native species remain unexplored as model systems for the study of the neuroendocrine bases of social behavior. In this review, we will revise recent data on the two model systems of Neotropical fish, South American cichlids and weakly electric fish that have contributed to this issue. Copyright © 2018 Elsevier Inc. All rights reserved.

The isolation, purification and amino-acid sequence of insulin from the teleost fish Cottus scorpius (daddy sculpin).

PubMed

Cutfield, J F; Cutfield, S M; Carne, A; Emdin, S O; Falkmer, S

1986-07-01

Insulin from the principal islets of the teleost fish, Cottus scorpius (daddy sculpin), has been isolated and sequenced. Purification involved acid/alcohol extraction, gel filtration, and reverse-phase high-performance liquid chromatography to yield nearly 1 mg pure insulin/g wet weight islet tissue. Biological potency was estimated as 40% compared to porcine insulin. The sculpin insulin crystallised in the absence of zinc ions although zinc is known to be present in the islets in significant amounts. Two other hormones, glucagon and pancreatic polypeptide, were copurified with the insulin, and an N-terminal sequence for pancreatic polypeptide was determined. The primary structure of sculpin insulin shows a number of sequence changes unique so far amongst teleost fish. These changes occur at A14 (Arg), A15 (Val), and B2 (Asp). The B chain contains 29 amino acids and there is no N-terminal extension as seen with several other fish. Presumably as a result of the amino acid substitutions, sculpin insulin does not readily form crystals containing zinc-insulin hexamers, despite the presence of the coordinating B10 His.

First evidences of Amazonian wildlife feeding on petroleum-contaminated soils: A new exposure route to petrogenic compounds?

PubMed

Orta-Martínez, Martí; Rosell-Melé, Antoni; Cartró-Sabaté, Mar; O'Callaghan-Gordo, Cristina; Moraleda-Cibrián, Núria; Mayor, Pedro

2018-01-01

Videos recorded with infrared camera traps placed in petroleum contaminated areas of the Peruvian Amazon have shown that four wildlife species, the most important for indigenous peoples' diet (lowland tapir, paca, red-brocket deer and collared peccary), consume oil-contaminated soils and water. Further research is needed to clarify whether Amazonian wildlife's geophagy can be a route of exposure to petrogenic contamination for populations living in the vicinity of oil extraction areas and relying on subsistence hunting. Copyright © 2017 Elsevier Inc. All rights reserved.

The participation of singlet oxygen in a photocitotoxicity of extract from amazon plant to cancer cells

NASA Astrophysics Data System (ADS)

Tcibulnikova, Anna V.; Degterev, Igor A.; Bryukhanov, Valery V.; Roberto, Mantuanelly M.; Campos Pereira, F. D.; Marin-Morales, M. A.; Slezhkin, Vasily A.; Samusev, Ilya G.

2018-01-01

We have been searching for new photosensitizers (PS) for photodynamic therapy (PDT) of cancer based on extracts from Amazonian plants since 2009. In this paper, we demonstrate that, under certain conditions, the extract from fruits of the Amazonian palm Euterpe oleraceae (popular name Açaí) can serve as a PS for PDT treatment of murine breast cancer cells (4T1 cell line). We have been first to show directly that the photodynamic effect of plant PS is due to singlet oxygen.

New species of Microcentrum Scudder, 1862 (Orthoptera: Tettigonioidea: Phaneropteridae) from Amazon rainforest.

PubMed

Da Silva Sovano, Rafael S; Cadena-Castañeda, Oscar J

2015-03-26

A regional study is performed for the Amazonian species of the genus Microcentrum Scudder, 1862, its proposed Microcentrum punctifrons Brunner von Wattenwyl, 1891 as nomen dubium n. stat. and two new species are described: Microcentrum amacayacu Cadena-Casteñada, Sovano n. sp. and Microcentrum xavieri Sovano, Cadena-Casteñada n. sp. the Colombian and Brazilian Amazon, respectively. A list and a key to the Amazonian species are also provided, along with a discussion on their distribution, according to endemism areas established to Amazon rainforest.

Wrinkle ridges in the floor material of Kasei Valles, Mars: Nature and origin

NASA Technical Reports Server (NTRS)

Watters, Thomas R.; Craddock, Robert A.

1991-01-01

Wrinkle ridges on Mars occur almost exclusively in smooth plains material referred to as ridged plains. One of the largest contiguous units of ridged plains occurs on Lunae Planum on the eastern flank of the Tharsis rise. The eastern, western, and northern margins of the ridged plains of Lunae Planum suffered extensive erosion in early Amazonian channel-forming events. The most dramatic example of erosion in early Amazonian plains is in Kasei Valles. The nature an origin of the wrinkle ridges in the floor material of Kasei Valles are discussed.

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

Sousa, Debora Batista Pinheiro, E-mail: deborabpsousa@gmail.com; Neta, Raimunda Nonata Fortes Carvalho

This study used micronucleus assays and erythrocyte indices in the freshwater fish tambaqui, Colossoma macropomum, to assess environmental impacts in the Environmental Protection Area at Maracanã, São Luis, Brazil. Fish were sampled from two locations within the protected area, Serena Lagoon and Ambude River, on four occasions. Biometric data (length and weight) and an aliquot of blood were collected from each fish for analysis. Erythrocyte indices including: mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were calculated, and blood samples were examined for micronuclei and nuclear morphological changes. Micronuclei were found in fish from both locations, althoughmore » the frequency was higher in fish from Ambude River. Nuclear morphological changes were identified only in fish collected from Ambude River. Several nuclear morphological changes were found in erythrocytes stained with Giemsa, including: micronuclei and binucleate nuclei. On average, erythrocyte indices were lower in fish collected from Ambude River than in those from Serena Lagoon. Our results indicate that micronuclei and erythrocyte indices can be used in C. macropomum as indicators of environmental health.« less

Evolution of vertebrate visual pigments.

PubMed

Bowmaker, James K

2008-09-01

The visual pigments of vertebrates evolved about 500 million years ago, before the major evolutionary step of the development of jaws. Four spectrally distinct classes of cone opsin evolved through gene duplication, followed by the rod opsin class that arose from the duplication of the middle-wave-sensitive cone opsin. All four cone classes are present in many extant teleost fish, reptiles and birds, but one or more classes have been lost in primitive fish, amphibians and mammals. Gene duplication within the cone classes, especially in teleosts, has resulted in multiple opsins being available, both temporally and spatially, during development.

Microsatellite data suggest significant population structure and differentiation within the malaria vector Anopheles darlingi in Central and South America.

PubMed

Mirabello, Lisa; Vineis, Joseph H; Yanoviak, Stephen P; Scarpassa, Vera M; Póvoa, Marinete M; Padilla, Norma; Achee, Nicole L; Conn, Jan E

2008-03-26

Anopheles darlingi is the most important malaria vector in the Neotropics. An understanding of A. darlingi's population structure and contemporary gene flow patterns is necessary if vector populations are to be successfully controlled. We assessed population genetic structure and levels of differentiation based on 1,376 samples from 31 localities throughout the Peruvian and Brazilian Amazon and Central America using 5-8 microsatellite loci. We found high levels of polymorphism for all of the Amazonian populations (mean RS = 7.62, mean HO = 0.742), and low levels for the Belize and Guatemalan populations (mean RS = 4.3, mean HO = 0.457). The Bayesian clustering analysis revealed five population clusters: northeastern Amazonian Brazil, southeastern and central Amazonian Brazil, western and central Amazonian Brazil, Peruvian Amazon, and the Central American populations. Within Central America there was low non-significant differentiation, except for between the populations separated by the Maya Mountains. Within Amazonia there was a moderate level of significant differentiation attributed to isolation by distance. Within Peru there was no significant population structure and low differentiation, and some evidence of a population expansion. The pairwise estimates of genetic differentiation between Central America and Amazonian populations were all very high and highly significant (FST = 0.1859 - 0.3901, P < 0.05). Both the DA and FST distance-based trees illustrated the main division to be between Central America and Amazonia. We detected a large amount of population structure in Amazonia, with three population clusters within Brazil and one including the Peru populations. The considerable differences in Ne among the populations may have contributed to the observed genetic differentiation. All of the data suggest that the primary division within A. darlingi corresponds to two white gene genotypes between Amazonia (genotype 1) and Central America, parts of Colombia and Venezuela (genotype 2), and are in agreement with previously published mitochondrial COI gene sequences interpreted as incipient species. Overall, it appears that two main factors have contributed to the genetic differentiation between the population clusters: physical distance between the populations and the differences in effective population sizes among the subpopulations.

Using a GCM analogue model to investigate the potential for Amazonian forest dieback

NASA Astrophysics Data System (ADS)

Huntingford, C.; Harris, P. P.; Gedney, N.; Cox, P. M.; Betts, R. A.; Marengo, J. A.; Gash, J. H. C.

A combined GCM analogue model and GCM land surface representation is used to investigate the influences of climatology and land surface parameterisation on modelled Amazonian vegetation change. This modelling structure (called IMOGEN) captures the main features of the changes in surface climate as estimated by a GCM with enhanced atmospheric greenhouse gas concentrations. Advantage is taken of IMOGEN's computational speed which allows multiple simulations to be carried out to assess the robustness of the GCM results. The timing of forest dieback is found to be sensitive to the initial ``pre-industrial'' climate, as well as uncertainties in the representation of land-atmosphere CO2 exchange. Changing from a Q10 form for plant dark and maintanence respiration (as used in the coupled GCM runs) to a respiration proportional to maximum photosynthesis, reduces the biomass lost from Amazonia in the 21st century. Replacing the GCM control climate (which has about 25% too little rain in the annual mean over Amazonia) with an observed climatology increases the CO2 concentration at which rainfall drops to critical levels, and thereby further delays the dieback. On the other hand, calibration of the canopy photosynthesis model against Amazonian flux data tends to lead to earlier forest dieback. Further advances are required in both GCM rainfall simulation and land-surface process representation before a clearer picture will emerge on the timing of possible Amazonian forest dieback. However, it seems likely that these advances will overall lead to projections of later forest dieback as GCM control climates become more realistic.

Physical Growth of the Shuar: Height, Weight, and BMI References for an Indigenous Amazonian Population

PubMed Central

URLACHER, SAMUEL S.; BLACKWELL, AARON D.; LIEBERT, MELISSA A.; MADIMENOS, FELICIA C.; CEPON-ROBINS, TARA J.; GILDNER, THERESA E.; SNODGRASS, J. JOSH; SUGIYAMA, LAWRENCE S.

2015-01-01

Objectives Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. Methods Mixed-longitudinal measures of height, weight, and BMI were collected from Shuar participants (n = 2,463; age 0–29 years). Centile growth curves and tables were created for each anthropometric variable of interest using GAMLSS. Pseudo-velocity and LMS curves were generated to further investigate Shuar patterns of growth and to facilitate comparison with U.S. CDC and multinational WHO growth references. Results The Shuar are small throughout life and exhibit complex patterns of growth that differ substantially from those of international references. Similar to other Amazonians, Shuar growth in weight compares more favorably to references than growth in height, resulting in BMI curves that approximate international medians. Several additional characteristics of Shuar development are noteworthy, including large observed variation in body size early in life, significant infant growth faltering, extended male growth into adulthood, and a markedly early female pubertal growth spurt in height. Phenotypic plasticity and genetic selection in response to local environmental factors may explain many of these patterns. Conclusions Providing a detailed reference of growth for the Shuar and other Amazonian populations, this study possesses direct clinical application and affords valuable insight into childhood health and the ecology of human growth. PMID:26126793

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.

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.

Changes to Intestinal Transport Physiology and Carbonate Production at Various CO2 Levels in a Marine Teleost, the Gulf Toadfish (Opsanus beta).

PubMed

Heuer, Rachael M; Munley, Kathleen M; Narsinghani, Nafis; Wingar, Jessica A; Mackey, Theresa; Grosell, Martin

2016-01-01

Most marine teleosts defend blood pH during high CO2 exposure by sustaining elevated levels of HCO3(-) in body fluids. In contrast to the gill, where measures are taken to achieve net base retention, elevated CO2 leads to base loss in the intestine of marine teleosts studied to date. This loss is thought to occur through transport pathways previously demonstrated to be involved with routine osmoregulation in marine teleosts. The main objective of this study was to characterize the intestinal transport physiology of the gulf toadfish (Opsanus beta) when exposed to varied levels of CO2: control, 5,000, 10,000, and 20,000 μatm CO2 (0.04, 0.5, 1, and 2 kPa, respectively). Results of this study suggest that intestinal apical anion exchange is highly responsive to hypercarbia, evidenced by a dose-dependent increase in intestinal luminal HCO3(-) (mmol L(-1)) that was mirrored by a reduction in Cl(-) (mmol L(-1)). Despite activation of HCO3(-) transport pathways typically used during osmoregulation, fractional fluid absorption was only significantly lower at the highest level of CO2. Although increased HCO3(-) excretion could provide more substrate for intestinally produced carbonates, carbonate production was not significantly increased during hypercarbia at the levels tested. This study is among the first to thoroughly characterize how compensation for elevated CO2 affects transport physiology and carbonate production in the marine fish intestine. This deeper understanding may be particularly relevant when considering the impacts of future predicted ocean acidification, where prolonged base loss may alter the energetic cost of acid-base balance or osmoregulation in marine fish.

The cranial cartilages of teleosts and their classification.

PubMed

Benjamin, M

1990-04-01

The structure and distribution of cartilages has been studied in 45 species from 24 families. The resulting data have been used as a basis for establishing a new classification. A cartilage is regarded as 'cell-rich' if its cells or their lacunae occupy more than half of the tissue volume. Five classes of cell-rich cartilage are recognised (a) hyaline-cell cartilage (common in the lips of bottom-dwelling cyprinids) and its subtypes fibro/hyaline-cell cartilage, elastic/hyaline-cell cartilage and lipo/hyaline-cell cartilage, (b) Schaffer's Zellknorpel, typified by the cartilage in the gill filaments of most teleosts examined, (c) elastic/cell-rich cartilage, such as that which supports the barbels and oral valves of catfish, e.g. Corydoras metae, (d) fibro/cell-rich cartilage, as in the submaxillary meniscus of Sphaerichthys osphromenoides, (e) cell-rich hyaline and (f) matrix-rich hyaline cartilage--both of which are common in the neurocranium and gill arches of most teleosts. The range of cartilages seen, and the predominant cartilage type, is recorded for each species and a list is provided of the tissues that most typify different organs or regions of the head. As a preliminary pointer to developmental relationships between the cartilages, note was taken of gradual transitions between one cartilage and another. It is suggested that hyaline-cell cartilage occupies a key position in teleosts as the most labile of the supporting tissues and is highly characteristic of Cypriniformes. The cartilage that best resembles mammalian hyaline cartilage (matrix-rich hyaline cartilage) has a very conservative distribution in different skeletal elements and the least number of associations with other tissues. It is well represented in Siluriformes.

A Phylogenetic Perspective on the Evolution of Mediterranean Teleost Fishes

PubMed Central

Meynard, Christine N.; Mouillot, David; Mouquet, Nicolas; Douzery, Emmanuel J. P.

2012-01-01

The Mediterranean Sea is a highly diverse, highly studied, and highly impacted biogeographic region, yet no phylogenetic reconstruction of fish diversity in this area has been published to date. Here, we infer the timing and geographic origins of Mediterranean teleost species diversity using nucleotide sequences collected from GenBank. We assembled a DNA supermatrix composed of four mitochondrial genes (12S ribosomal DNA, 16S ribosomal DNA, cytochrome c oxidase subunit I and cytochrome b) and two nuclear genes (rhodopsin and recombination activating gene I), including 62% of Mediterranean teleost species plus 9 outgroups. Maximum likelihood and Bayesian phylogenetic and dating analyses were calibrated using 20 fossil constraints. An additional 124 species were grafted onto the chronogram according to their taxonomic affinity, checking for the effects of taxonomic coverage in subsequent diversification analyses. We then interpreted the time-line of teleost diversification in light of Mediterranean historical biogeography, distinguishing non-endemic natives, endemics and exotic species. Results show that the major Mediterranean orders are of Cretaceous origin, specifically ∼100–80 Mya, and most Perciformes families originated 80–50 Mya. Two important clade origin events were detected. The first at 100–80 Mya, affected native and exotic species, and reflects a global diversification period at a time when the Mediterranean Sea did not yet exist. The second occurred during the last 50 Mya, and is noticeable among endemic and native species, but not among exotic species. This period corresponds to isolation of the Mediterranean from Indo-Pacific waters before the Messinian salinity crisis. The Mediterranean fish fauna illustrates well the assembly of regional faunas through origination and immigration, where dispersal and isolation have shaped the emergence of a biodiversity hotspot. PMID:22590545

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.

Different expression patterns of renal Na+/K+-ATPase α-isoform-like proteins between tilapia and milkfish following salinity challenges.

PubMed

Yang, Wen-Kai; Chung, Chang-Hung; Cheng, Hui Chen; Tang, Cheng-Hao; Lee, Tsung-Han

2016-12-01

Euryhaline teleosts can survive in a broad range of salinity via alteration of the molecular mechanisms in certain osmoregulatory organs, including in the gill and kidney. Among these mechanisms, Na + /K + -ATPase (NKA) plays a crucial role in triggering ion-transporting systems. The switch of NKA isoforms in euryhaline fish gills substantially contributes to salinity adaptation. However, there is little information about switches in the kidneys of euryhaline teleosts. Therefore, the responses of the renal NKA α-isoform protein switch to salinity challenge in euryhaline tilapia (Oreochromis mossambicus) and milkfish (Chanos chanos) with different salinity preferences were examined and compared in this study. Immunohistochemical staining in tilapia kidneys revealed the localization of NKA in renal tubules rather than in the glomeruli, similar to our previous findings in milkfish kidneys. Protein abundance in the renal NKA pan α-subunit-like, α1-, and α3-isoform-like proteins in seawater-acclimated tilapia was significantly higher than in the freshwater group, whereas the α2-isoform-like protein exhibited the opposite pattern of expression. In the milkfish, higher protein abundance in the renal NKA pan α-subunit-like and α1-isoform-like proteins was found in freshwater-acclimated fish, whereas no difference was found in the protein abundance of α2- and α3-isoform-like proteins between groups. These findings suggested that switches for renal NKA α-isoforms, especially the α1-isoform, were involved in renal osmoregulatory mechanisms of euryhaline teleosts. Moreover, differences in regulatory responses of the renal NKA α-subunit to salinity acclimation between tilapia and milkfish revealed that divergent mechanisms for maintaining osmotic balance might be employed by euryhaline teleosts with different salinity preferences. Copyright © 2016 Elsevier Inc. All rights reserved.

Relaxin-related gene expression differs between anadromous and stream-resident stickleback (Gasterosteus aculeatus) following seawater transfer.

PubMed

Kusakabe, Makoto; Ishikawa, Asano; Kitano, Jun

2014-09-01

Relaxin (RLN) is a hormone that was originally identified as a regulator of pregnancy and reproduction. However, recent mammalian studies have demonstrated that relaxins also have potent osmoregulatory actions. In mammals, six relaxin family peptides have been identified: RLN1/2, RLN3, insulin-like peptide (INSL) 3, INSL4, INSL5, and INSL6. Previous genome database searches have revealed that teleosts also possess multiple relaxin family genes. However, the functions of these relaxin family peptides in teleosts remain unclear. In order to gain insight into the osmoregulatory functions of teleost relaxins, we studied the relaxin family peptides in euryhaline three-spined sticklebacks (Gasterosteus aculeatus), which have diversified into a variety of ecotypes. Rln3a, rln3b, and rln transcripts were abundant in the stickleback brain, whereas insl5b transcript levels were highest in the intestine among tissues. Seawater challenge experiments showed that transcript levels of rln3a, rln3b, and rln in the brain changed significantly after seawater transfer. Particularly, rln3b showed different patterns of temporal changes between anadromous and stream-resident morphs. The transcript levels of relaxin family peptide receptors, rxfp1, rxfp2b, rxfp3-2a, and rxfp3-2b, did not exhibit substantial changes in the brain, although these were constantly higher in the anadromous morph than the stream-resident morph. These results suggest that stickleback relaxin systems are differentially regulated by salinity signals, at least at the transcriptional level, and anadromous and stream-resident morphs differ in relaxin signaling pathways. The differences in the expression of relaxin-related genes between these two morphs provide a foundation for further exploration of the osmoregulatory function of relaxins in teleosts. Copyright © 2014 Elsevier Inc. All rights reserved.

The Role of Competition in Structuring Primate Communities under Different Productivity Regimes in the Amazon

PubMed Central

Rocha, Juliana Monteiro de Almeida; Pinto, Míriam Plaza; Boubli, Jean Philippe; Grelle, Carlos Eduardo Viveiros

2015-01-01

The factors responsible for the formation of Amazonian primate communities are not well understood. Here we investigated the influence of interspecific competition in the assembly of these communities, specifically whether they follow an assembly rule known as "favored states". According to this rule, interspecific competition influences final species composition, resulting in functional groups that are equally represented in the community. We compiled presence-absence data for primate species at 39 Amazonian sites in Brazil, contrasting two regions with distinct productivity regimes: the eutrophic Juruá River basin and the oligotrophic Negro River basin. We tested two hypotheses: that interspecific competition is a mechanism that influences the structure of Amazonian primate communities, and that competition has had a greater influence on the structure of primate communities in regions with low productivity, where resources are more limited. We used null models to test the statistical significance of the results, and found a non-random pattern compatible with the favored states rule in the two regions. Our findings suggest that interspecific competition is an important force driving primate community assembly regardless of productivity regimes. PMID:26696089

Paleoproterozoic volcanic centers of the São Félix do Xingu region, Amazonian craton, Brazil: Hydrothermal alteration and metallogenetic potential

NASA Astrophysics Data System (ADS)

da Cruz, Raquel Souza; Fernandes, Carlos Marcello Dias; Villas, Raimundo Netuno Nobre; Juliani, Caetano; Monteiro, Lena Virgínia Soares; Lagler, Bruno; Misas, Carlos Mario Echeverri

2016-06-01

Geological, petrographic, scanning electron microscopy, and X-ray diffraction studies revealed hydrothermalized lithotypes evidenced by overprinted zones of potassic, propylitic, sericitic, and intermediate argillic alterations types, with pervasive and fracture-controlled styles, in Paleoproterozoic volcano-plutonic units of the São Félix do Xingu region, Amazonian craton, northern Brazil. The Sobreiro Formation presents propylitic (epidote + chlorite + carbonate + clinozoisite + sericite + quartz ± albite ± hematite ± pyrite), sericitic (sericite + quartz + carbonate), and potassic (potassic feldspar + hematite) alterations. The prehnite-pumpellyite pair that is common in geothermal fields also occurs in this unit. The Santa Rosa Formation shows mainly potassic (biotite + microcline ± magnetite), sericitic (sericite + quartz + carbonate ± chlorite ± gold), and intermediate argillic (montmorillonite + kaolinite/halloysite + illite) alterations. These findings strongly suggest the involvement of magma-sourced and meteoric fluids and draw attention to the metallogenetic potential of these volcanic units for Paleoproterozoic epithermal and rare and base metal porphyry-type mineralizations, similar to those already identified in other portions of the Amazonian craton.

Application of a linear spectral model to the study of Amazonian squall lines during GTE/ABLE 2B

NASA Technical Reports Server (NTRS)

Silva Dias, Maria A. F.; Ferreira, Rosana N.

1992-01-01

A linear nonhydrostatic spectral model is run with the basic state, or large scale, vertical profiles of temperature and wind observed prior to convective development along the northern coast of South America during the GTE/ABLE 2B. The model produces unstable modes with mesoscale wavelength and propagation speed comparable to observed Amazonian squall lines. Several tests with different vertical profiles of low-level winds lead to the conclusion that a shallow and/or weak low-level jet either does not produce a scale selection or, if it does, the selected mode is stationary, indicating the absence of a propagating disturbance. A 700-mbar jet of 13 m/s, with a 600-mbar wind speed greater or equal to 10 m/s, is enough to produce unstable modes with propagating features resembling those of observed Amazonian squall lines. However, a deep layer of moderate winds (about 10 m/s) may produce similar results even in the absence of a low-level wind maximum. The implications in terms of short-term weather forecasting are discussed.

Parasitism of the isopod Artystone trysibia in the fish Chaetostoma dermorhynchum from the Tena River (Amazonian region, Ecuador).

PubMed

Junoy, Juan

2016-01-01

The isopod Artystone trysibia Schioedte, 1866 is described by using a collection of specimens that were found parasitizing loricariid fish Chaetostoma dermorhynchum Boulenger, 1887 in the Tena River (Napo province, Ecuador, Amazonian region). Additionally to freshly collected specimens, complementary data of the parasite was obtained from preserved fishes at Ecuadorian museums. This is the first record of A. trysibia in Ecuador, and the most upstream location for the species. The new host fish, Chaetostoma dermorhynchum, is used locally as food. Copyright © 2015 Elsevier B.V. All rights reserved.

Cross-system comparisons of soil nitrogen transformations and nitrous oxide flux in tropical forest ecosystems

NASA Technical Reports Server (NTRS)

Matson, Pamela A.; Vitousek, Peter M.

1987-01-01

Soil nitrogen transformations and nitrous oxide flux across the soil-air interface have been measured in a variety of tropical forest sites and correlated with patterns of nitrogen circulation. Nitrogen mineralizaton and nitrification potentials were found to be high in the relatively fertile Costa Rica sites and the Amazonian oxisol/ultisols, intermediate in Amazonian white sand soils, and low in the Hawaiian montane sites. Nitrous oxide fluxes ranged from 0 to 6.2 ng/sq cm per h, and the mean flux per site was shown to be highly correlated with mean nitrogen mineralization.

The use of smoke acid as an alternative coagulating agent for natural rubber sheets' production.

PubMed

Ferreira, Vanda S; Rêgo, Ione N C; Pastore, Floriano; Mandai, Mariana M; Mendes, Leonardo S; Santos, Karin A M; Rubim, Joel C; Suarez, Paulo A Z

2005-03-01

A comparative study of rubber sheets obtained using formic, acetic, and smoke acid as coagulants is shown for latex obtained from native Amazonian trees and also from commercial cultivated trees. The evaluation of both processes of coagulation was carried out by spectroscopic and physical-chemical analysis, showing no differences in the rubber sheets obtained. This new method of rubber sheet preparation was introduced into Amazonian rainforest rubber tapper communities, which are actually producing in large scale. The physical-mechanical properties were similar among a large sheets made by different rubber tapper communities using this new method.

A new cryptic species and review of the east-Andean leaf chafer genus Mesomerodon Ohaus, 1905 (Coleoptera, Scarabaeidae, Rutelinae).

PubMed

Seidel, Matthias; Jameson, Mary L; Stone, Rachel L

2017-01-01

The Neotropical scarab beetle genus Mesomerodon Ohaus (Scarabaeidae: Rutelinae: Rutelini) is distributed in the western (lowland) Amazonian region from Colombia to Bolivia. Based on our research, the genus includes three species including a new cryptic species from Ecuador. We use niche modeling to predict potential suitable habitat and identify environmental factors associated with the distribution of Mesomerodon species. We characterize the genus, provide a key to species, diagnose each species, describe a new species, provide spatial and temporal distributions, and discuss distributions of the species in relation to Amazonian landscape biodiversity.

Comments on "Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations" [J. Acoust. Soc. Am. 114, 66-69 (2003)].

PubMed

Sousa-Lima, Renata S

2006-06-01

This letter concerns the paper "Intraspecific and geographic variation of West Indian manatee (Trichechus manatus spp.) vocalizations" [Nowacek et al., J. Acoust. Soc. Am. 114, 66-69 (2003)]. The purpose here is to correct the fundamental frequency range and information on intraindividual variation in the vocalizations of Amazonian manatees reported by Nowacek et al. (2003) in citing the paper "Signature information and individual recognition in the isolation calls of Amazonian manatees, Trichechus inunguis (Mammalia: Sirenia)" [Sousa-Lima et al., Anim. Behav. 63, 301-310 (2002)].

Recycling of Amazonian detrital zircons in the Mixteco terrane, southern Mexico: Paleogeographic implications during Jurassic-Early Cretaceous and Paleogene times

NASA Astrophysics Data System (ADS)

Silva-Romo, Gilberto; Mendoza-Rosales, Claudia Cristina; Campos-Madrigal, Emiliano; Morales-Yáñez, Axél; de la Torre-González, Alam Israel; Nápoles-Valenzuela, Juan Ivan

2018-04-01

In the northeastern Mixteco terrane of southern Mexico, in the Ixcaquixtla-Atzumba region, the recycling of Amazonian detrital zircons records the paleogeography during the Mesozoic period in the context of the breakup of Pangea, a phenomenon that disarticulated the Sanozama-La Mora paleo-river. The clastic units of southern Mexico in the Ayuquila, Otlaltepec and Zapotitlán Mesozoic basins, as well as in the Atzumba Cenozoic basin, are characterized by detrital zircon contents with ages specific to the Amazonian craton, ranging between 3040 and 1278 Ma. The presence of zircons of Amazonian affinity suggests a provenance by recycling from carrier units such as the La Mora Formation or the Ayú Complex. In the area, the Ayú and Acatlán complexes form the Cosoltepec block, a paleogeographic element that during Early Cretaceous time acted as the divide between the slopes of the paleo-Gulf of Mexico and the paleo-Pacific Ocean. The sedimentological characteristics of the Jurassic-Cenozoic clastic successions in the Ixcaquixtla-Atzumba region denote relatively short transport in braided fluvial systems and alluvial fans. In this way, several basins are recognized around the Cosoltepec block. At the southeastern edge of the Cosoltepec block, the Ayuquila and Tecomazúchil formations accumulated in the Ayuquila continental basin on the paleo-Pacific Ocean slope. On the other hand, within the paleo-Gulf of Mexico slope, in the Otlaltepec continental basin, the Piedra Hueca and the Otlaltepec formations accumulated. The upper member of the Santa Lucía Formation accumulated in a transitional environment on the southwestern shoulder of the Zapotitlán basin, as well as on the paleo-Gulf of Mexico slope. In the Ayuquila basin, a marine transgression is recognized that advanced from south to north during the Late Jurassic. At the northeastern edge of the Cosoltepec block, we propose that the Santa Lucía formation attests to a transgression from the paleo-Gulf of Mexico during the Early Cretaceous. Thus, the Cosoltepec block flood occurred during the Albian-Cenomanian, as recognized by the Cipiapa Limestone accumulation. The subsequent uplift of the region and its incorporation into the continental slope is attested by the Atzumba Formation, which offers further evidence of the content of Amazonian detrital zircons recycled from the Ayú Complex. The Atzumba Formation accumulated as alluvial fans during the Paleogene at the hanging wall of the Chazumba fault, which displaced the Cosoltepec block. That is, the detrital zircons in the clastic successions of the Ixcaquixtla-Atzumba region bear indirect testimony to the origin and Amazonian affinity of the Ayú Complex and/or other lithodemes of the Acatlán Complex.

'Twisted plywood' structure and mineralization in the scales of a primitive living fish Amia calva.

PubMed

Meunier, F J

1981-01-01

The basal plate of the scales of Amia calva is composed of regular double twisted plywood, as in Latimeria and Dipnoan scales. However, the progressive rotation of the fibrils direction is left-handed in Amia and right-handed in the 'Sarcopterygians'. So, the similarity between these peculiar plywoods is probably the result of convergence. The basal plate of Amia scales is incompletely mineralized. There are numerous calcified ovoid corpuscles which look very like the Mandl's corpuscles of Teleost scales. The mineralization probably progresses essentially by the fusion of these corpuscles, as in Teleost scales, and would be inotropic rather than spheritic.

Virus diseases of the salmonidae in the western United States. III. Immunopathological aspects

USGS Publications Warehouse

Klontz, George W.; Yasutake, William T.; Parisot, T.J.

1965-01-01

The immune response among fish, from a phylogenetic standpoint, presents a progressive pattern of increasing development. The cyclostomes have been shown to have only feeble immunologic responsiveness. One of their number, the hagfish, appeared to be totally lacking in the ability to actively acquire antibodies.Among the elasmobranchs, the sharks have received the most study immunologically. This group demonstrated a variable response to antigenic stimulationOf the teleosts, the salmonids and the cyprinids have been the more frequent recipients of experimentally introduced antigens. These fishes, as well as other species of teleosts, are quite active and quite consistent in their response to various antigens.

Glutamine metabolism in a holostean (Amia calva) and teleost fish (Salvelinus namaycush).

PubMed

Chamberlin, M E; Glemet, H C; Ballantyne, J S

1991-01-01

Amino acid metabolism was examined in mitochondria from the lateral red muscle of a teleost (lake char, Salvelinus namaycush) and a nonteleost fish (bowfin, Amia calva). Isolated mitochondria oxidize a wide variety of substrates and have high respiratory control ratios. In both species, glutamine is oxidized more rapidly than any other amino acid. The rate of glutamine oxidation by bowfin mitochondria exceeds that of lake char mitochondria, and the bowfin displays correspondingly higher levels of mitochondrial phosphate-dependent glutaminase. It is suggested that amino acids in general, and glutamine in particular, are important oxidative substrates for nonteleost red muscle. The teleost red muscle, however, may rely on both glutamine and fatty acids as oxidative substrates. It appears that glutamate derived from glutamine is oxidized primarily via glutamate dehydrogenase, whereas exogenous glutamate is oxidized primarily via aspartate aminotransferase. Complete oxidation of glutamine may be accomplished in the absence of other substrates by conversion of glutamine-derived malate to pyruvate via malic enzyme. To assess the relative abilities of various tissues to synthesize and oxidize glutamine, the activities of glutamine synthetase and glutaminase were measured. The results of these studies indicate that the organization of glutamine metabolism of fish differs markedly from that in mammals.

Branchial placenta in the viviparous teleost Ilyodon whitei (Goodeidae).

PubMed

Uribe, Mari Carmen; De la Rosa-Cruz, Gabino; García-Alarcón, Adriana

2014-12-01

Intraluminal gestation, as it occurs in viviparous goodeids, allows a wide diversity of embryo-maternal metabolic exchanges. The branchial placenta occurs in embryos developing in intraluminal gestation when ovarian folds enter through the operculum, into the branchial chamber. The maternal ovarian folds may extend to the embryonic pharyngeal cavity. A branchial placenta has been observed in few viviparous teleosts, and there are not previous histological analyses. This study analysis the histological structure in the goodeid Ilyodon whitei. The moterno ovarian folds extend through the embryonic operculum and reach near the gills, occupying part of the branchial chamber. These folds extend also into the pharyngeal cavity. In some regions, the epithelia of the ovarian folds and embryo were in apposition, developing a placental structure in which, maternal and embryonic capillaries lie in close proximity. The maternal epithelium has desquamated cells which may enter through the branchial chamber to the pharyngeal cavity and the alimentary tract. The complex processes that occur in the ovaries of viviparous teleosts, and its diverse adaptations for viviparity, as the presence of branchial placenta, are relevant in the study of the evolution of vertebrate viviparity. © 2014 Wiley Periodicals, Inc.

Functional evidence for the inflammatory reflex in teleosts: A novel α7 nicotinic acetylcholine receptor modulates the macrophage response to dsRNA.

PubMed

Torrealba, Débora; Balasch, Joan Carles; Criado, Manuel; Tort, Lluís; Mackenzie, Simon; Roher, Nerea

2018-07-01

The inflammatory reflex modulates the innate immune system, keeping in check the detrimental consequences of overstimulation. A key player controlling the inflammatory reflex is the alpha 7 acetylcholine receptor (α7nAChR). This receptor is one of the signalling molecules regulating cytokine expression in macrophages. In this study, we characterize a novel teleost α7nAChR. Protein sequence analysis shows a high degree of conservation with mammalian orthologs and trout α7nAChR has all the features and essential amino acids to form a fully functional receptor. We demonstrate that trout macrophages can bind α-bungarotoxin (α-BTX), a competitive antagonist for α7nAChRs. Moreover, nicotine stimulation produces a decrease in pro-inflammatory cytokine expression after stimulation with poly(I:C). These results suggest the presence of a functional α7nAChR in the macrophage plasma membrane. Further, in vivo injection of poly(I:C) induced an increase in serum ACh levels in rainbow trout. Our results manifest for the first time the functional conservation of the inflammatory reflex in teleosts. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evolution of complement as an effector system in innate and adaptive immunity.

PubMed

Sunyer, J Oriol; Boshra, Hani; Lorenzo, Gema; Parra, David; Freedman, Bruce; Bosch, Nina

2003-01-01

For a long time, the complement system in mammals has been regarded as a biological system that plays an essential role in innate immunity. More recently, it has been recognized that the complement system contributes heavily to the generation and development of an acquired immune response. In fact, this ancient mechanism of defense has evolved from a primitive mechanism of innate immune recognition in invertebrate species to that of an effector system that bridges the innate with the adaptive immune response in vertebrate species. When and how did complement evolve into a shared effector system between innate and adaptive immunity? To answer this question, our group is interested in understanding the role of complement in innate and adaptive immune responses in an evolutionary relevant species: the teleost fish. The attractiveness of this species as an animal model is based on two important facts. First, teleost fish are one of the oldest animal species to have developed an adaptive immune response. Second, the complement system of teleost fish offers a unique feature, which is the structural and functional diversity of its main effector protein, C3, the third component of the complement system.

Aquaporin-4 immunoreactivity in Müller and amacrine cells of marine teleost fish retina.

PubMed

Hombrebueno, José R; Lee, Eun-Jin; Martínez-Ruiz, Noemí; García-Alcázar, Alicia; Grzywacz, Norberto M; De Juan, Joaquín

2012-01-13

Aquaporins (AQPs) are membrane proteins that facilitate water transport across biological membranes and are essential for the proper function of neural tissue. Although AQPs have been extensively studied in mammalian retina, their presence in lower vertebrate retina is less frequently characterized. AQP4 expressed in mammalian and chick Müller cells plays a major part in maintaining retinal homeostasis. In this study, we examined the immunoreactivity of AQP4 in the adult retina of gilthead sea bream (Sparus aurata-teleost fish), during light and dark adaptation. The AQP4 expression was detected in Müller cell somas at the inner nuclear layer and in the end-feet processes near the vitreoretinal border. Moreover, AQP4 was also evident in cone photoreceptor cells and in a GABAergic subpopulation of amacrine cells (AQP4-ACs). Four different types of AQP4-ACs were characterized based on their morphology and dendrite stratification. Interestingly, a stronger AQP4 immunoreactivity was observed in the inner nuclear layer during dark adaptation, accompanied by a significant increment in AQP4-ACs cell size. Hence, AQP4 may play an important role in water distribution in the teleost fish retina. Copyright © 2011 Elsevier B.V. All rights reserved.

Genome-Wide Identification and Transcriptome-Based Expression Profiling of the Sox Gene Family in the Nile Tilapia (Oreochromis niloticus)

PubMed Central

Wei, Ling; Yang, Chao; Tao, Wenjing; Wang, Deshou

2016-01-01

The Sox transcription factor family is characterized with the presence of a Sry-related high-mobility group (HMG) box and plays important roles in various biological processes in animals, including sex determination and differentiation, and the development of multiple organs. In this study, 27 Sox genes were identified in the genome of the Nile tilapia (Oreochromis niloticus), and were classified into seven groups. The members of each group of the tilapia Sox genes exhibited a relatively conserved exon-intron structure. Comparative analysis showed that the Sox gene family has undergone an expansion in tilapia and other teleost fishes following their whole genome duplication, and group K only exists in teleosts. Transcriptome-based analysis demonstrated that most of the tilapia Sox genes presented stage-specific and/or sex-dimorphic expressions during gonadal development, and six of the group B Sox genes were specifically expressed in the adult brain. Our results provide a better understanding of gene structure and spatio-temporal expression of the Sox gene family in tilapia, and will be useful for further deciphering the roles of the Sox genes during sex determination and gonadal development in teleosts. PMID:26907269

Genome-Wide Identification and Transcriptome-Based Expression Profiling of the Sox Gene Family in the Nile Tilapia (Oreochromis niloticus).

PubMed

Wei, Ling; Yang, Chao; Tao, Wenjing; Wang, Deshou

2016-02-23

The Sox transcription factor family is characterized with the presence of a Sry-related high-mobility group (HMG) box and plays important roles in various biological processes in animals, including sex determination and differentiation, and the development of multiple organs. In this study, 27 Sox genes were identified in the genome of the Nile tilapia (Oreochromis niloticus), and were classified into seven groups. The members of each group of the tilapia Sox genes exhibited a relatively conserved exon-intron structure. Comparative analysis showed that the Sox gene family has undergone an expansion in tilapia and other teleost fishes following their whole genome duplication, and group K only exists in teleosts. Transcriptome-based analysis demonstrated that most of the tilapia Sox genes presented stage-specific and/or sex-dimorphic expressions during gonadal development, and six of the group B Sox genes were specifically expressed in the adult brain. Our results provide a better understanding of gene structure and spatio-temporal expression of the Sox gene family in tilapia, and will be useful for further deciphering the roles of the Sox genes during sex determination and gonadal development in teleosts.

The mucosal immune system of fish: the evolution of tolerating commensals while fighting pathogens

PubMed Central

Gomez, Daniela; Sunyer, J Oriol; Salinas, Irene

2013-01-01

The field of mucosal immunology research has grown fast over the past few years, and our understanding on how mucosal surfaces respond to complex antigenic cocktails is expanding tremendously. With the advent of new molecular sequencing techniques, it is easier to understand how the immune system of vertebrates is, to a great extent, orchestrated by the complex microbial communities that live in symbiosis with their hosts. The commensal microbiota is now seen as the “extended self” by many scientists. Similarly, fish immunologist are devoting important research efforts to the field of mucosal immunity and commensals. Recent breakthroughs on our understanding of mucosal immune responses in teleost fish open up the potential of teleosts as animal research models for the study of human mucosal diseases. Additionally, this new knowledge places immunologists in a better position to specifically target the fish mucosal immune system while rationally designing mucosal vaccines and other immunotherapies. In this review, an updated view on how teleost skin, gills and gut immune cells and molecules, function in response to pathogens and commensals is provided. Finally, some of the future avenues that the field of fish mucosal immunity may follow in the next years are highlighted. PMID:24099804

Development of an in vitro model system to study the interactions between Mycobacterium marinum and teleost neutrophils.

PubMed

Hodgkinson, Jordan W; Ge, Jun-Qing; Katzenback, Barbara A; Havixbeck, Jeffrey J; Barreda, Daniel R; Stafford, James L; Belosevic, Miodrag

2015-12-01

The lack of a reliable mammalian neutrophil in vitro culture system has restricted our ability to examine their precise roles in mycobacterial infections. Previously, we developed the procedures for the isolation and culture of primary kidney-derived neutrophil-like cells from goldfish that are functionally and morphologically similar to mammalian neutrophils. The cultured primary goldfish neutrophils exhibited prolonged viability and functional effector responses. In this study, we demonstrate that when exposed to live or heat-killed Mycobacterium marinum, goldfish neutrophils increased their mRNA levels for several pro-inflammatory cytokines (il-1β1, il-1β2, tnfα-1, tnfα-2) and the cytokine receptors (ifngr1-1, tnfr1, tnfr2). These neutrophils also exhibited chemotaxis toward live mycobacteria, internalized the bacilli, and produced reactive oxygen intermediates (ROI) in response to pathogen exposure. The survival of intracellular mycobacteria was significantly reduced in activated neutrophils, indicating a robust killing response by these teleost granulocytes. We suggest that this goldfish primary neutrophil in vitro model system will provide important information regarding neutrophil-mediated host defense mechanisms against mycobacteria in teleosts as well as in higher vertebrates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Healing of corneal epithelial wounds in marine and freshwater fish.

PubMed

Ubels, J L; Edelhauser, H F

The corneal epithelium of a fish is in direct contact with the aquatic environment and is a barrier to movement of ions and water into and through the cornea. This tissue layer is thus important in maintenance of corneal transparency. When the epithelium is wounded, its protective function is lost and corneal transparency remains compromised until the epithelial barrier is re-established. This study was undertaken to investigate the healing response of the fish cornea to epithelial abrasion. Wounds were stained with fluorescein and photographed during healing. Wound areas were measured by planimetry. The cornea of the sculpin, a marine teleost, becomes edematous after wounding and heals at 2.54 to 3.42 mm2/hr. Nonswelling corneas of the elasmobranchs--dogfish shark and skate--heal at 1.29 mm2/hr, respectively. The wounded eye of the rainbow trout, a freshwater teleost, is stressed by the low osmolality of the environment. Severe corneal edema and cataracts develop following epithelial wounding, and the cornea heals at 0.64 mm2/hr. Although the healing rates in teleosts differ from those in mammals, histology shows that the corneal healing mechanism is essentially the same in fish and mammals.

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

The fate of the duplicated androgen receptor in fishes: a late neofunctionalization event?

PubMed Central

2008-01-01

Background Based on the observation of an increased number of paralogous genes in teleost fishes compared with other vertebrates and on the conserved synteny between duplicated copies, it has been shown that a whole genome duplication (WGD) occurred during the evolution of Actinopterygian fish. Comparative phylogenetic dating of this duplication event suggests that it occurred early on, specifically in teleosts. It has been proposed that this event might have facilitated the evolutionary radiation and the phenotypic diversification of the teleost fish, notably by allowing the sub- or neo-functionalization of many duplicated genes. Results In this paper, we studied in a wide range of Actinopterygians the duplication and fate of the androgen receptor (AR, NR3C4), a nuclear receptor known to play a key role in sex-determination in vertebrates. The pattern of AR gene duplication is consistent with an early WGD event: it has been duplicated into two genes AR-A and AR-B after the split of the Acipenseriformes from the lineage leading to teleost fish but before the divergence of Osteoglossiformes. Genomic and syntenic analyses in addition to lack of PCR amplification show that one of the duplicated copies, AR-B, was lost in several basal Clupeocephala such as Cypriniformes (including the model species zebrafish), Siluriformes, Characiformes and Salmoniformes. Interestingly, we also found that, in basal teleost fish (Osteoglossiformes and Anguilliformes), the two copies remain very similar, whereas, specifically in Percomorphs, one of the copies, AR-B, has accumulated substitutions in both the ligand binding domain (LBD) and the DNA binding domain (DBD). Conclusion The comparison of the mutations present in these divergent AR-B with those known in human to be implicated in complete, partial or mild androgen insensitivity syndrome suggests that the existence of two distinct AR duplicates may be correlated to specific functional differences that may be connected to the well-known plasticity of sex determination in fish. This suggests that three specific events have shaped the present diversity of ARs in Actinopterygians: (i) early WGD, (ii) parallel loss of one duplicate in several lineages and (iii) putative neofunctionalization of the same duplicate in percomorphs, which occurred a long time after the WGD. PMID:19094205

Stratigraphical evidence of late Amazonian periglaciation and glaciation in the Astapus Colles region of Mars

NASA Astrophysics Data System (ADS)

Soare, Richard J.; Osinski, Gordon R.

2009-07-01

Recent modeling of the meteorological conditions during and following times of high obliquity suggests that an icy mantle could have been emplaced in western Utopia Planitia by atmospheric deposition during the late Amazonian period [Costard, F.M., Forget, F., Madeleine, J.B., Soare, R.J., Kargel, J.S., 2008. Lunar Planet. Sci. 39. Abstract 1274; Madeleine, B., Forget, F., Head, J.W., Levrard, B., Montmessin, F., 2007. Lunar Planet. Sci. 38. Abstract 1778]. Astapus Colles (ABa) is a late Amazonian geological unit - located in this hypothesized area of accumulation - that comprises an icy mantle tens of meters thick [Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. For the most part, this unit drapes the early Amazonian Vastitas Borealis interior unit (ABvi); to a lesser degree it overlies the early Amazonian Vastitas Borealis marginal unit (ABvm) and the early to late Hesperian UP plains unit HBu2 [Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. Landscapes possibly modified by late-Amazonian periglacial processes [Costard, F.M., Kargel, J.S., 1995. Icarus 114, 93-112; McBride, S.A., Allen, C.C., Bell, M.S., 2005. Lunar Planet. Sci. 36. Abstract 1090; Morgenstern, A., Hauber, E., Reiss, D., van Gasselt, S., Grosse, G., Schirrmeister, L., 2007. J. Geophys. Res. 112, doi:10.1029/2006JE002869. E06010; Seibert, N.M., Kargel, J.S., 2001. Geophys. Res. Lett. 28, 899-902; Soare, R.J., Kargel, J.S., Osinski, G.R., Costard, F., 2007. Icarus 191, 95-112; Soare, R.J., Osinski, G.R., Roehm, C.L., 2008. Earth Planet. Sci. Lett. 272, 382-393] and glacial processes [Milliken, R.E., Mustard, J.F., Goldsby, D.L., 2003. J. Geophys. Res. 108 (E6), doi:10.1029/2002JE002005. 5057; Mustard, J.F., Cooper, C.D., Rifkin, M.K., 2001. Nature 412, 411-414; Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888] have been reported within the region. Researchers have assumed that the periglacial and glacial landscapes occur within the same geological unit, the ABa [i.e., Morgenstern, A., Hauber, E., Reiss, D., van Gasselt, S., Grosse, G., Schirrmeister, L., 2007. J. Geophys. Res. 112; doi:10.1029/2006JE002869. E06010; Tanaka, K.L., Skinner, J.A., Hare, T.M., 2005. US Geol. Surv. Sci. Invest., Map 2888]. In this study we use HiRISE (High Resolution Image Science Experiment, Mars Reconnaissance Orbiter) imagery to identify the stratigraphical separation of the two landscapes and show that periglacial landscape modification has occurred in the geological units that underlie the ABa, not in the ABa itself. Moreover, we suggest that the periglacial landscape extends well beyond the perimeter of the ABa and could be the product of "wet" cold-climate processes. These processes involve freeze-thaw cycles and intermittently stable liquid-water at or near the surface. By contrast, we propose that the ABa is a very recent late-Amazonian geological unit formed principally by "dry" cold-climate processes. These processes comprise accumulation (by atmospheric deposition) and ablation (by sublimation).

Fire-free land use in pre-1492 Amazonian savannas

PubMed Central

Iriarte, José; Power, Mitchell J.; Rostain, Stéphen; Mayle, Francis E.; Jones, Huw; Watling, Jennifer; Whitney, Bronwen S.; McKey, Doyle B.

2012-01-01

The nature and scale of pre-Columbian land use and the consequences of the 1492 “Columbian Encounter” (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions. PMID:22493248

The fate of Amazonian ecosystems over the coming century arising from changes in climate, atmospheric CO2, and land use.

PubMed

Zhang, Ke; de Almeida Castanho, Andrea D; Galbraith, David R; Moghim, Sanaz; Levine, Naomi M; Bras, Rafael L; Coe, Michael T; Costa, Marcos H; Malhi, Yadvinder; Longo, Marcos; Knox, Ryan G; McKnight, Shawna; Wang, Jingfeng; Moorcroft, Paul R

2015-02-20

There is considerable interest in understanding the fate of the Amazon over the coming century in the face of climate change, rising atmospheric CO 2 levels, ongoing land transformation, and changing fire regimes within the region. In this analysis, we explore the fate of Amazonian ecosystems under the combined impact of these four environmental forcings using three terrestrial biosphere models (ED2, IBIS, and JULES) forced by three bias-corrected IPCC AR4 climate projections (PCM1, CCSM3, and HadCM3) under two land-use change scenarios. We assess the relative roles of climate change, CO 2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change are primarily determined by the direction and severity of projected changes in regional precipitation: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%. However, the models predict that CO 2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and, as a result, sustain high biomass forests, even under the driest climate scenario. Land-use change and climate-driven changes in fire frequency are predicted to cause additional aboveground biomass loss and reductions in forest extent. The relative impact of land use and fire dynamics compared to climate and CO 2 impacts varies considerably, depending on both the climate and land-use scenario, and on the terrestrial biosphere model used, highlighting the importance of improved quantitative understanding of all four factors - climate change, CO 2 fertilization effects, fire, and land use - to the fate of the Amazon over the coming century. © 2015 John Wiley & Sons Ltd.

Fish are central in the diet of Amazonian riparians: should we worry about their mercury concentrations?

PubMed

Dorea, Jose G

2003-07-01

The Amazon rain forest extends over an area of 7.8x10(6)km(2) in nine countries. It harbors a diverse human population distributed in dense cities and isolated communities with extreme levels of infrastructure. Amazonian forest people, either autochthons or frontier riparians (ribeirinhos) living in isolated areas, share the same environment for survival and nutritional status. The peculiarities of the hydrological cycle determine disease patterns, agricultural conditions, and food availability. Feeding strategies depend heavily on cassava products and fish. These two foods carry toxic substances such as linamarin (naturally present in cassava) and monomethyl mercury (MMHg) (bioconcentrated in fish flesh) that cause neurotoxic diseases in other parts of the world but not in Amazonia, where neurotoxic cases of food origin are rare and not related to these staples. While cassava detoxification processes may partly explain its safe consumption, the Hg concentrations in Amazonian fish are within traditionally safe limits for this population and contribute to an important metabolic interaction with cassava. The gold rush of the 1970s and 1980s brought large-scale environmental disruption and physical destruction of ecosystems at impact points, along with a heavy discharge of metallic Hg. The discharged Hg has not yet impacted on MMHg concentrations in fish or in hair of fish consumers. Hair Hg concentration, used as a biomarker of fish consumption, indicates that the Amazonian riparians are acquiring an excellent source of protein carrying important nutrients, the lack of which could aggravate their existing health problems. Therefore, in a scenario of insufficient health services and an unhealthy environment, food habits based on fish consumption are part of a successful survival strategy and recommendations for changes are not yet justifiable.

Large-scale degradation of Amazonian freshwater ecosystems

NASA Astrophysics Data System (ADS)

Castello, L.; Macedo, M.

2016-12-01

The integrity of freshwater ecosystems depends on their hydrological connectivity with land, water, and climate systems. Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. However, the hydrological connectivity of Amazonian freshwater ecosystems is increasingly disrupted by construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation; evaluates their impacts on hydrological connectivity; and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 155 large hydroelectric dams in operation, 21 dams under construction, and there will be only three free-flowing tributaries if all 277 planned dams for the Basin are built. Land-cover changes driven by mining, dam and road construction, and agriculture and cattle ranching have already affected 20% of the Basin and up to 50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g. droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and do not consider the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basin-wide research and policy framework to understand and manage hydrological connectivity across multiple spatial scales and jurisdictional boundaries.

Physical growth of the shuar: Height, Weight, and BMI references for an indigenous amazonian population.

PubMed

Urlacher, Samuel S; Blackwell, Aaron D; Liebert, Melissa A; Madimenos, Felicia C; Cepon-Robins, Tara J; Gildner, Theresa E; Snodgrass, J Josh; Sugiyama, Lawrence S

2016-01-01

Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. Mixed-longitudinal measures of height, weight, and body mass index (BMI) were collected from Shuar participants (n = 2,463; age: 0-29 years). Centile growth curves and tables were created for each anthropometric variable of interest using Generalized Additive Models for Location, Scale, and Shape (GAMLSS). Pseudo-velocity and Lambda-Mu-Sigma curves were generated to further investigate Shuar patterns of growth and to facilitate comparison with United States Center for Disease Control and Prevention and multinational World Health Organization growth references. The Shuar are small throughout life and exhibit complex patterns of growth that differ substantially from those of international references. Similar to other Amazonians, Shuar growth in weight compares more favorably to references than growth in height, resulting in BMI curves that approximate international medians. Several additional characteristics of Shuar development are noteworthy, including large observed variation in body size early in life, significant infant growth faltering, extended male growth into adulthood, and a markedly early female pubertal growth spurt in height. Phenotypic plasticity and genetic selection in response to local environmental factors may explain many of these patterns. Providing a detailed reference of growth for the Shuar and other Amazonian populations, this study possesses direct clinical application and affords valuable insight into childhood health and the ecology of human growth. © 2015 Wiley Periodicals, Inc.

Simulation of the Unexpected Photosynthetic Seasonality in Amazonian Evergreen Forests by Using an Improved Diffuse Fraction-Based Light Use Efficiency Model

NASA Astrophysics Data System (ADS)

Yan, Hao; Wang, Shao-Qiang; da Rocha, Humberto R.; Rap, Alexandru; Bonal, Damien; Butt, Nathalie; Coupe, Natalia Restrepo; Shugart, Herman H.

2017-11-01

Understanding the mechanism of photosynthetic seasonality in Amazonian evergreen forests is critical for its formulation in global climate and carbon cycle models. However, the control of the unexpected photosynthetic seasonality is highly uncertain. Here we use eddy-covariance data across a network of Amazonian research sites and a novel evapotranspiration (E) and two-leaf-photosynthesis-coupled model to investigate links between photosynthetic seasonality and climate factors on monthly scales. It reproduces the GPP seasonality (R2 = 0.45-0.69) with a root-mean-square error (RMSE) of 0.67-1.25 g C m-2 d-1 and a Bias of -0.03-1.04 g C m-2 d-1 for four evergreen forest sites. We find that the proportion of diffuse and direct sunlight governs the photosynthetic seasonality via their interaction with sunlit and shaded leaves, supported by a proof that canopy light use efficiency (LUE) has a strong linear relationship with the fraction of diffuse sunlight for Amazonian evergreen forests. In the transition from dry season to rainy season, incident total radiation (Q) decreased while LUE and diffuse fraction increased, which produced the large seasonal increase ( 34%) in GPP of evergreen forests. We conclude that diffuse radiation is an important environmental driver of the photosynthetic seasonality in tropical Amazon forests yet depending on light utilization by sunlit and shaded leaves. Besides, the GPP model simulates the precipitation-dominated GPP seasonality (R2 = 0.40-0.69) at pasture and savanna sites. These findings present an improved physiological method to relate light components with GPP in tropical Amazon.

Candida amazonensis sp. nov., an ascomycetous yeast isolated from rotting wood in the Amazonian forest.

PubMed

Cadete, Raquel M; Melo, Monaliza A; Lopes, Mariana R; Pereira, Gilmara M D; Zilli, Jerri E; Vital, Marcos J S; Gomes, Fátima C O; Lachance, Marc-André; Rosa, Carlos A

2012-06-01

Five strains of a novel yeast species were isolated from rotting wood samples collected in an Amazonian forest site in the state of Roraima, northern Brazil. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the Scheffersomyces clade and is related to Candida coipomoensis, Candida lignicola and Candida queiroziae. The novel species Candida amazonensis sp. nov. is proposed to accommodate these isolates. The type strain of C. amazonensis sp. nov. is UFMG-HMD-26.3(T) ( = CBS 12363(T) = NRRL Y-48762(T)).

Natural infection of Lutzomyia tortura with Leishmania (Viannia) naiffi in an Amazonian area of Ecuador.

PubMed

Kato, Hirotomo; Gomez, Eduardo A; Yamamoto, Yu-ichi; Calvopiña, Manuel; Guevara, Angel G; Marco, Jorge D; Barroso, Paola A; Iwata, Hiroyuki; Hashiguchi, Yoshihisa

2008-09-01

Natural infection of sand flies with Leishmania parasites was surveyed in an Amazonian area in Ecuador where leishmaniasis is endemic. Seventy-one female sand flies were dissected and one was positive for Leishmania protozoa. The species of this sand fly was identified as Lutzomyia (Lu.) tortura on the basis of morphologic characteristics. Analysis of the cytochrome b gene sequence identified the parasite as L. (Viannia) naiffi. We report the distribution of L. (V.) naiffi in Ecuador and detection of a naturally infected sand fly in the Ecuadorian Amazon and natural infection of Lu. tortura with Leishmania parasites in the New World.

Legacy Effect of Amazonian Drought Delays the Season Transition from Dry to Wet

NASA Astrophysics Data System (ADS)

Shi, M.; Liu, J.; Wong, S.; Worden, J. R.; Fisher, J.; Frankenberg, C.

2017-12-01

The long-term drought effect on forest coverage, so-called legacy effect, has been observed in ground and remote sensing measurements. Drought and forest loss may amplify each other through vegetation-atmosphere feedbacks. In this study, we investigate the impact of the reduced growth of southern Amazonian forest from the 2005 drought on dry-to-wet season transition and its variations in 2005 and 2006. We quantified the vegetation-atmosphere feedbacks with the Community Atmosphere Model version 5 (CAM5) with a control and a sensitivity experiments. We further investigate the mechanism of vegetation-atmosphere feedbacks with data-constrained evapotranspiration (ET) and HDO/H2O observations from the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) and from the Tropospheric Emission Spectrometer (TES). Our results show that the dry season end (DSE) in southern Amazonian forest was delayed by 15 days in 2005 and by 25 days in 2006 with drought induced leaf carbon pool reduction. The postponed DSE is triggered by the reduced evapotranspiration (ET), but amplified by change of large-scale circulation. The reduction of ET and its delaying effect on dry-wet season transition is further confirmed with SCIAMACHY and TES HDO/H2O measurements.

Soil transmitted helminthiasis in indigenous groups. A community cross sectional study in the Amazonian southern border region of Ecuador

PubMed Central

Romero-Sandoval, Natalia; Ortiz-Rico, Claudia; Sánchez-Pérez, Héctor Javier; Valdivieso, Daniel; Sandoval, Carlos; Pástor, Jacob; Martín, Miguel

2017-01-01

Background Rural communities in the Amazonian southern border of Ecuador have benefited from governmental social programmes over the past 9 years, which have addressed, among other things, diseases associated with poverty, such as soil transmitted helminth infections. The aim of this study was to explore the prevalence of geohelminth infection and several factors associated with it in these communities. Methods This was a cross sectional study in two indigenous communities of the Amazonian southern border of Ecuador. The data were analysed at both the household and individual levels. Results At the individual level, the prevalence of geohelminth infection reached 46.9% (95% CI 39.5% to 54.2%), with no differences in terms of gender, age, temporary migration movements or previous chemoprophylaxis. In 72.9% of households, one or more members were infected. Receiving subsidies and overcrowding were associated with the presence of helminths. Conclusions The prevalence of geohelminth infection was high. Our study suggests that it is necessary to conduct studies focusing on communities, and not simply on captive groups, such as schoolchildren, with the object of proposing more suitable and effective strategies to control this problem. PMID:28292765

The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa

PubMed Central

ter Steege, Hans; Vaessen, Rens W.; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C. A.; Jørgensen, Peter Møller; Salomão, Rafael P.

2016-01-01

Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites. PMID:27406027

High levels of cryptic species diversity uncovered in Amazonian frogs

PubMed Central

Funk, W. Chris; Caminer, Marcel; Ron, Santiago R.

2012-01-01

One of the greatest challenges for biodiversity conservation is the poor understanding of species diversity. Molecular methods have dramatically improved our ability to uncover cryptic species, but the magnitude of cryptic diversity remains unknown, particularly in diverse tropical regions such as the Amazon Basin. Uncovering cryptic diversity in amphibians is particularly pressing because amphibians are going extinct globally at an alarming rate. Here, we use an integrative analysis of two independent Amazonian frog clades, Engystomops toadlets and Hypsiboas treefrogs, to test whether species richness is underestimated and, if so, by how much. We sampled intensively in six countries with a focus in Ecuador (Engystomops: 252 individuals from 36 localities; Hypsiboas: 208 individuals from 65 localities) and combined mitochondrial DNA, nuclear DNA, morphological, and bioacoustic data to detect cryptic species. We found that in both clades, species richness was severely underestimated, with more undescribed species than described species. In Engystomops, the two currently recognized species are actually five to seven species (a 150–250% increase in species richness); in Hypsiboas, two recognized species represent six to nine species (a 200–350% increase). Our results suggest that Amazonian frog biodiversity is much more severely underestimated than previously thought. PMID:22130600

The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa.

PubMed

Ter Steege, Hans; Vaessen, Rens W; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C A; Jørgensen, Peter Møller; Salomão, Rafael P

2016-07-13

Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species' range size is a better predictor of the number of times it has been collected than the species' estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites.

Palaeontological evidence for the last temporal occurrence of the ancient western Amazonian river outflow into the Caribbean.

PubMed

Aguilera, Orangel; Lundberg, John; Birindelli, Jose; Sabaj Pérez, Mark; Jaramillo, Carlos; Sánchez-Villagra, Marcelo R

2013-01-01

Fossil catfishes from fluvio-lacustrine facies of late Miocene Urumaco, early Pliocene Castilletes and late Pliocene San Gregorio formations provide evidence of a hydrographic connection in what is today desert regions of northern Colombia and Venezuela. New discoveries and reevaluation of existing materials leads to the recognition of two new records of the pimelodid Brachyplatystoma cf. vaillantii, and of three distinct doradid taxa: Doraops sp., Rhinodoras sp., and an unidentified third form. The presence of fossil goliath long-whiskered catfishes and thorny catfishes are indicative of the persistence of a fluvial drainage system inflow into the South Caribbean during the Pliocene/Pleistocene boundary, complementary to the previous western Amazonian hydrographic system described from the Middle Miocene Villavieja Formation in central Colombia and Late Miocene Urumaco Formation in northwestern Venezuela. The Pliocene Castilletes and San Gregorio formations potentially represent the last lithostratigraphic units related with an ancient western Amazonian fish fauna and that drainage system in the Caribbean. Alternatively, it may preserve faunas from a smaller, peripheral river basin that was cut off earlier from the Amazon-Orinoco, today found in the Maracaibo basin and the Magdalena Rivers.

Palaeontological Evidence for the Last Temporal Occurrence of the Ancient Western Amazonian River Outflow into the Caribbean

PubMed Central

Aguilera, Orangel; Lundberg, John; Birindelli, Jose; Sabaj Pérez, Mark; Jaramillo, Carlos; Sánchez-Villagra, Marcelo R.

2013-01-01

Fossil catfishes from fluvio-lacustrine facies of late Miocene Urumaco, early Pliocene Castilletes and late Pliocene San Gregorio formations provide evidence of a hydrographic connection in what is today desert regions of northern Colombia and Venezuela. New discoveries and reevaluation of existing materials leads to the recognition of two new records of the pimelodid Brachyplatystoma cf. vaillantii, and of three distinct doradid taxa: Doraops sp., Rhinodoras sp., and an unidentified third form. The presence of fossil goliath long-whiskered catfishes and thorny catfishes are indicative of the persistence of a fluvial drainage system inflow into the South Caribbean during the Pliocene/Pleistocene boundary, complementary to the previous western Amazonian hydrographic system described from the Middle Miocene Villavieja Formation in central Colombia and Late Miocene Urumaco Formation in northwestern Venezuela. The Pliocene Castilletes and San Gregorio formations potentially represent the last lithostratigraphic units related with an ancient western Amazonian fish fauna and that drainage system in the Caribbean. Alternatively, it may preserve faunas from a smaller, peripheral river basin that was cut off earlier from the Amazon-Orinoco, today found in the Maracaibo basin and the Magdalena Rivers. PMID:24098778

The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa

NASA Astrophysics Data System (ADS)

Ter Steege, Hans; Vaessen, Rens W.; Cárdenas-López, Dairon; Sabatier, Daniel; Antonelli, Alexandre; de Oliveira, Sylvia Mota; Pitman, Nigel C. A.; Jørgensen, Peter Møller; Salomão, Rafael P.

2016-07-01

Amazonia is the most biodiverse rainforest on Earth, and the debate over how many tree species grow there remains contentious. Here we provide a checklist of all tree species collected to date, and describe spatial and temporal trends in data accumulation. We report 530,025 unique collections of trees in Amazonia, dating between 1707 and 2015, for a total of 11,676 species in 1225 genera and 140 families. These figures support recent estimates of 16,000 total Amazonian tree species based on ecological plot data from the Amazonian Tree Diversity Network. Botanical collection in Amazonia is characterized by three major peaks, centred around 1840, 1920, and 1980, which are associated with flora projects and the establishment of inventory plots. Most collections were made in the 20th century. The number of collections has increased exponentially, but shows a slowdown in the last two decades. We find that a species’ range size is a better predictor of the number of times it has been collected than the species’ estimated basin-wide population size. Finding, describing, and documenting the distribution of the remaining species will require coordinated efforts at under-collected sites.

Water-rich Martian mantle can account for the elastic thickness in Amazonian era

NASA Astrophysics Data System (ADS)

Katayama, I.; Matsuoka, Y.; Azuma, S.

2016-12-01

Although high water content in the Martian mantle is inferred from cosmochemistry, the direct measurements of water in the SNC meteorites are controversial, because hydrogen is a highly mobile element and the later terrestrial alteration can modify the primarily concentration in the Mars. On the one hand, water has a significant effect on the rock strength in both brittle and ductile fields; consequently, the presence of water can influence the elastic thickness that is primary controlled by stress distribution in the lithosphere. The Martian elastic lithosphere estimated from gravity and topography data indicates different thickness at the time of loading (e.g. McGovern et al. 2002). The increase of elastic thickness from Noachian to Hesperian is most likely related to the secular cooling in the Mars; however, the nearly constant elastic lithosphere in Amazonian cannot be explained by the thermal evolution alone. In this study, we applied recent rheological data to the Martian lithosphere and tested whether water can account for the elastic thickness seen in the Amazonian era. We incorporated the effect of pore fluid pressure in the brittle regime and Peierls mechanism in the ductile regime in the rheological model, which are not applied in the most previous calculation (e.g. Grott and Breuer 2008) but have a significant influence on the stress distribution in the lithosphere. Since the pore pressure reduces the effective normal stress on the fault plane, the maximum stress in the brittle regime is markedly decreased by the presence of pore fluid. The estimate of elastic lithosphere is dependent on thermal structure, and we used the heat production rate obtained from the Mars Odyssey spectrometry as thermal model (Hahn et al. 2011). Our results indicate the elastic thickness in Amazonian era of 120-170 km for dry condition and 80-110 km for wet condition. The thin elastic thickness calculated under wet environments is a result of significant reduction of flexure moment in the lithosphere. Our model indicates that water-rich Martian lithosphere can be responsible for the observed elastic thickness in Amazonian. However, the model is highly sensitive to the thermal structure and curvature, and more realistic data of heat flow targeted by the Insight mission would provide the robust water concentration in the Martian mantle.

Calcium uptake in the skin of a freshwater teleost.

PubMed Central

McCormick, S D; Hasegawa, S; Hirano, T

1992-01-01

The skin, particularly the opercular membrane of some teleosts, contains mitochondrion-rich "chloride" cells and has been widely used as a model to study branchial salt-extrusion mechanisms in seawater fish. Skin isolated from the operculum of the freshwater Nile tilapia (Oreochromis niloticus) can transport Ca2+ against an ionic and electrical gradient. Adaptation of Nile tilapia to a low-Ca2+ environment increased the capacity of the opercular membrane to transport Ca2+. The density of mitochondrion-rich cells increased in parallel with Ca2+ transport capacity. The results demonstrate net Ca2+ uptake by vertebrate skin and strongly implicate mitochondrion-rich cells as the site of Ca2+ uptake in fresh water. Images PMID:1565659

Pituitary gland morphogenesis and ontogeny of adenohypophyseal cells of Salminus brasiliensis (Teleostei, Characiformes).

PubMed

de Jesus, Lázaro Wender Oliveira; Chehade, Chayrra; Costa, Fabiano Gonçalves; Borella, Maria Inês

2014-06-01

In this study, we describe for the first time the details of the pituitary gland morphogenesis and the ontogeny of adenohypophyseal cells of a South American Characiform species with great importance for Brazilian Aquaculture, Salminus brasiliensis (Characiformes, Characidae), from hatching to 25 days after hatching (dah), by histochemical and immunocytochemical methods. The pituitary placode was first detected at hatching (0 dah), and the pituitary anlage became more defined at 0.5 dah. The neurohypophysis (NH) development started at 3 dah, and the early formation of its stalk at 12.5 dah. An increase in adenohypophyseal and NH tissues was also observed, and in juveniles at 25 dah, the pituitary displayed similar morphology to that found in adults of this species, displaying the main features of the teleost pituitary. PRL cells were detected at 0.5 dah, together with ACTH and α-MSH cells, followed by GH and SL cells at 1.5 dah. β-FSH cells were detected at 25 dah, while β-LH cells at 5 dah. The pituitary development in this species comprises a dynamic process similar to other teleosts. Our findings in S. brasiliensis corroborate the heterogeneity in the ontogeny of adenohypophyseal cells in teleosts and suggest a role for adenohypophyseal hormones in the early development of this species.

Serotonin Coordinates Responses to Social Stress-What We Can Learn from Fish.

PubMed

Backström, Tobias; Winberg, Svante

2017-01-01

Social interaction is stressful and subordinate individuals are often subjected to chronic stress, which greatly affects both their behavior and physiology. In teleost fish the social position of an individual may have long-term effects, such as effects on migration, age of sexual maturation or even sex. The brain serotonergic system plays a key role in coordinating autonomic, behavioral and neuroendocrine stress responses. Social subordination results in a chronic activation of the brain serotonergic system an effect, which seems to be central in the subordinate phenotype. However, behavioral effects of short-term acute activation of the serotonergic system are less obvious. As in other vertebrates, divergent stress coping styles, often referred to as proactive and reactive, has been described in teleosts. As demonstrated by selective breeding, stress coping styles appear to be partly heritable. However, teleost fish are characterized by plasticity, stress coping style being affected by social experience. Again, the brain serotonergic system appears to play an important role. Studies comparing brain gene expression of fish of different social rank and/or displaying divergent stress coping styles have identified several novel factors that seem important for controlling aggressive behavior and stress coping, e.g., histamine and hypocretin/orexin. These may also interact with brain monoaminergic systems, including serotonin.

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth

PubMed Central

Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

2014-01-01

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. PMID:25098636

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth.

PubMed

Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

2013-01-01

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. © 2013 Wiley Periodicals, Inc.

Evolutionary origins of taste buds: phylogenetic analysis of purinergic neurotransmission in epithelial chemosensors

PubMed Central

Kirino, Masato; Parnes, Jason; Hansen, Anne; Kiyohara, Sadao; Finger, Thomas E.

2013-01-01

Taste buds are gustatory endorgans which use an uncommon purinergic signalling system to transmit information to afferent gustatory nerve fibres. In mammals, ATP is a crucial neurotransmitter released by the taste cells to activate the afferent nerve fibres. Taste buds in mammals display a characteristic, highly specific ecto-ATPase (NTPDase2) activity, suggesting a role in inactivation of the neurotransmitter. The purpose of this study was to test whether the presence of markers of purinergic signalling characterize taste buds in anamniote vertebrates and to test whether similar purinergic systems are employed by other exteroceptive chemosensory systems. The species examined include several teleosts, elasmobranchs, lampreys and hagfish, the last of which lacks vertebrate-type taste buds. For comparison, Schreiner organs of hagfish and solitary chemosensory cells (SCCs) of teleosts, both of which are epidermal chemosensory end organs, were also examined because they might be evolutionarily related to taste buds. Ecto-ATPase activity was evident in elongate cells in all fish taste buds, including teleosts, elasmobranchs and lampreys. Neither SCCs nor Schreiner organs show specific ecto-ATPase activity, suggesting that purinergic signalling is not crucial in those systems as it is for taste buds. These findings suggest that the taste system did not originate from SCCs but arose independently in early vertebrates. PMID:23466675

Evolutionary origins of taste buds: phylogenetic analysis of purinergic neurotransmission in epithelial chemosensors.

PubMed

Kirino, Masato; Parnes, Jason; Hansen, Anne; Kiyohara, Sadao; Finger, Thomas E

2013-03-06

Taste buds are gustatory endorgans which use an uncommon purinergic signalling system to transmit information to afferent gustatory nerve fibres. In mammals, ATP is a crucial neurotransmitter released by the taste cells to activate the afferent nerve fibres. Taste buds in mammals display a characteristic, highly specific ecto-ATPase (NTPDase2) activity, suggesting a role in inactivation of the neurotransmitter. The purpose of this study was to test whether the presence of markers of purinergic signalling characterize taste buds in anamniote vertebrates and to test whether similar purinergic systems are employed by other exteroceptive chemosensory systems. The species examined include several teleosts, elasmobranchs, lampreys and hagfish, the last of which lacks vertebrate-type taste buds. For comparison, Schreiner organs of hagfish and solitary chemosensory cells (SCCs) of teleosts, both of which are epidermal chemosensory end organs, were also examined because they might be evolutionarily related to taste buds. Ecto-ATPase activity was evident in elongate cells in all fish taste buds, including teleosts, elasmobranchs and lampreys. Neither SCCs nor Schreiner organs show specific ecto-ATPase activity, suggesting that purinergic signalling is not crucial in those systems as it is for taste buds. These findings suggest that the taste system did not originate from SCCs but arose independently in early vertebrates.

How predation shaped fish: the impact of fin spines on body form evolution across teleosts.

PubMed

Price, S A; Friedman, S T; Wainwright, P C

2015-11-22

It is well known that predators can induce morphological changes in some fish: individuals exposed to predation cues increase body depth and the length of spines. We hypothesize that these structures may evolve synergistically, as together, these traits will further enlarge the body dimensions of the fish that gape-limited predators must overcome. We therefore expect that the orientation of the spines will predict which body dimension increases in the presence of predators. Using phylogenetic comparative methods, we tested this prediction on the macroevolutionary scale across 347 teleost families, which display considerable variation in fin spines, body depth and width. Consistent with our predictions, we demonstrate that fin spines on the vertical plane (dorsal and anal fins) are associated with a deeper-bodied optimum. Lineages with spines on the horizontal plane (pectoral fins) are associated with a wider-bodied optimum. Optimal body dimensions across lineages without spines paralleling the body dimension match the allometric expectation. Additionally, lineages with longer spines have deeper and wider body dimensions. This evolutionary relationship between fin spines and body dimensions across teleosts reveals functional synergy between these two traits and a potential macroevolutionary signature of predation on the evolutionary dynamics of body shape. © 2015 The Author(s).

Conservation of the photoperiodic neuroendocrine axis among vertebrates: evidence from the teleost fish, Gasterosteus aculeatus

PubMed Central

O’Brien, Conor S.; Bourdo, Ryan; Bradshaw, William E.; Holzapfel, Christina M.; Cresko, William. A.

2012-01-01

Photoperiod, or length of day, has a predictable annual cycle, making it an important cue for the timing of seasonal behavior and development in many organisms. Photoperiod is widely used among temperate and polar animals to regulate the timing of sexual maturation. The proper sensing and interpretation of photoperiod can be tightly tied to an organism’s overall fitness. In photoperiodic mammals and birds the thyroid hormone pathway initiates sexual maturation, but the degree to which this pathway is conserved across other vertebrates is not well known. We use the threespine stickleback Gasterosteus aculeatus, as a representative teleost to quantify the photoperiodic response of key genes in the thyroid hormone pathway under controlled laboratory conditions. We find that the photoperiodic responses of the hormones are largely consistent amongst multiple populations, although differences suggest physiological adaptation to various climates. We conclude that the thyroid hormone pathway initiates sexual maturation in response to photoperiod in G. aculeatus, and our results show that more components of this pathway are conserved among mammals, birds, and teleost fish than was previously known. However, additional endocrinology, cell biology and molecular research will be required to define precisely which aspects of the pathway are conserved across vertebrates. PMID:22504272

Conservation of the photoperiodic neuroendocrine axis among vertebrates: evidence from the teleost fish, Gasterosteus aculeatus.

PubMed

O'Brien, Conor S; Bourdo, Ryan; Bradshaw, William E; Holzapfel, Christina M; Cresko, William A

2012-08-01

Photoperiod, or length of day, has a predictable annual cycle, making it an important cue for the timing of seasonal behavior and development in many organisms. Photoperiod is widely used among temperate and polar animals to regulate the timing of sexual maturation. The proper sensing and interpretation of photoperiod can be tightly tied to an organism's overall fitness. In photoperiodic mammals and birds the thyroid hormone pathway initiates sexual maturation, but the degree to which this pathway is conserved across other vertebrates is not well known. We use the threespine stickleback Gasterosteus aculeatus, as a representative teleost to quantify the photoperiodic response of key genes in the thyroid hormone pathway under controlled laboratory conditions. We find that the photoperiodic responses of the hormones are largely consistent amongst multiple populations, although differences suggest physiological adaptation to various climates. We conclude that the thyroid hormone pathway initiates sexual maturation in response to photoperiod in G. aculeatus, and our results show that more components of this pathway are conserved among mammals, birds, and teleost fish than was previously known. However, additional endocrinology, cell biology and molecular research will be required to define precisely which aspects of the pathway are conserved across vertebrates. Copyright © 2012 Elsevier Inc. All rights reserved.

The Asian arowana (Scleropages formosus) genome provides new insights into the evolution of an early lineage of teleosts

PubMed Central

Bian, Chao; Hu, Yinchang; Ravi, Vydianathan; Kuznetsova, Inna S.; Shen, Xueyan; Mu, Xidong; Sun, Ying; You, Xinxin; Li, Jia; Li, Xiaofeng; Qiu, Ying; Tay, Boon-Hui; Thevasagayam, Natascha May; Komissarov, Aleksey S.; Trifonov, Vladimir; Kabilov, Marsel; Tupikin, Alexey; Luo, Jianren; Liu, Yi; Song, Hongmei; Liu, Chao; Wang, Xuejie; Gu, Dangen; Yang, Yexin; Li, Wujiao; Polgar, Gianluca; Fan, Guangyi; Zeng, Peng; Zhang, He; Xiong, Zijun; Tang, Zhujing; Peng, Chao; Ruan, Zhiqiang; Yu, Hui; Chen, Jieming; Fan, Mingjun; Huang, Yu; Wang, Min; Zhao, Xiaomeng; Hu, Guojun; Yang, Huanming; Wang, Jian; Wang, Jun; Xu, Xun; Song, Linsheng; Xu, Gangchun; Xu, Pao; Xu, Junmin; O’Brien, Stephen J.; Orbán, László; Venkatesh, Byrappa; Shi, Qiong

2016-01-01

The Asian arowana (Scleropages formosus), one of the world’s most expensive cultivated ornamental fishes, is an endangered species. It represents an ancient lineage of teleosts: the Osteoglossomorpha. Here, we provide a high-quality chromosome-level reference genome of a female golden-variety arowana using a combination of deep shotgun sequencing and high-resolution linkage mapping. In addition, we have also generated two draft genome assemblies for the red and green varieties. Phylogenomic analysis supports a sister group relationship between Osteoglossomorpha (bonytongues) and Elopomorpha (eels and relatives), with the two clades together forming a sister group of Clupeocephala which includes all the remaining teleosts. The arowana genome retains the full complement of eight Hox clusters unlike the African butterfly fish (Pantodon buchholzi), another bonytongue fish, which possess only five Hox clusters. Differential gene expression among three varieties provides insights into the genetic basis of colour variation. A potential heterogametic sex chromosome is identified in the female arowana karyotype, suggesting that the sex is determined by a ZW/ZZ sex chromosomal system. The high-quality reference genome of the golden arowana and the draft assemblies of the red and green varieties are valuable resources for understanding the biology, adaptation and behaviour of Asian arowanas. PMID:27089831

A ddRAD-based genetic map and its integration with the genome assembly of Japanese eel (Anguilla japonica) provides insights into genome evolution after the teleost-specific genome duplication

PubMed Central

2014-01-01

Background Recent advancements in next-generation sequencing technology have enabled cost-effective sequencing of whole or partial genomes, permitting the discovery and characterization of molecular polymorphisms. Double-digest restriction-site associated DNA sequencing (ddRAD-seq) is a powerful and inexpensive approach to developing numerous single nucleotide polymorphism (SNP) markers and constructing a high-density genetic map. To enrich genomic resources for Japanese eel (Anguilla japonica), we constructed a ddRAD-based genetic map using an Ion Torrent Personal Genome Machine and anchored scaffolds of the current genome assembly to 19 linkage groups of the Japanese eel. Furthermore, we compared the Japanese eel genome with genomes of model fishes to infer the history of genome evolution after the teleost-specific genome duplication. Results We generated the ddRAD-based linkage map of the Japanese eel, where the maps for female and male spanned 1748.8 cM and 1294.5 cM, respectively, and were arranged into 19 linkage groups. A total of 2,672 SNP markers and 115 Simple Sequence Repeat markers provide anchor points to 1,252 scaffolds covering 151 Mb (13%) of the current genome assembly of the Japanese eel. Comparisons among the Japanese eel, medaka, zebrafish and spotted gar genomes showed highly conserved synteny among teleosts and revealed part of the eight major chromosomal rearrangement events that occurred soon after the teleost-specific genome duplication. Conclusions The ddRAD-seq approach combined with the Ion Torrent Personal Genome Machine sequencing allowed us to conduct efficient and flexible SNP genotyping. The integration of the genetic map and the assembled sequence provides a valuable resource for fine mapping and positional cloning of quantitative trait loci associated with economically important traits and for investigating comparative genomics of the Japanese eel. PMID:24669946

Corticosteroids stimulate the amphibious behavior in mudskipper: potential role of mineralocorticoid receptors in teleost fish.

PubMed

Sakamoto, Tatsuya; Mori, Chie; Minami, Shogo; Takahashi, Hideya; Abe, Tsukasa; Ojima, Daisuke; Ogoshi, Maho; Sakamoto, Hirotaka

2011-10-24

It has long been held that cortisol, a glucocorticoid in many vertebrates, carries out both glucocorticoid and mineralocorticoid actions in teleost fish. However, 11-deoxycorticosterone (DOC) has been identified as a specific endogenous ligand for the teleostean mineralocorticoid receptor (MR). Furthermore, the expressions of MR mRNA are modest in the osmoregulatory organs, but considerably higher in the brain of most teleosts. These recent findings suggest that the mineralocorticoid system (DOC/MR) may carry out some behavioral functions in fish. To test this possibility, we examined the effects of cortisol and DOC administration in the amphibious behavior in mudskipper (Periophthalmus modestus) in vivo. It was found that mudskippers remained in the water for an increased period of time when they were immersed into 5 μM DOC or cortisol for 8h. Additionally, an exposure to 25 μM DOC for 4 to 8 h caused a decreased migratory frequency of mudskippers to the water, reflected a tendency to remain in the water. It was further observed that after 8 h of intracerebroventricular (ICV) injection with 0.3 pmol DOC or cortisol the staying period in the water increased in fish. The migratory frequency was decreased after ICV DOC injection which indicated that fishes stayed in the water. Concurrent ICV injections of cortisol with RU486 [a specific glucocorticoid-receptor (GR) antagonist] inhibited only the partial effects of cortisol. Together with no changes in the plasma DOC concentrations under terrestrial conditions, these results indicate the involvement of brain MRs as cortisol receptors in the preference for an aquatic habitat of mudskippers. Although the role of GR signaling cannot be excluded in the aquatic preference, our data further suggest that the MR may play an important role in the brain dependent behaviors of teleost fish. Copyright © 2011 Elsevier Inc. All rights reserved.

The cranial cartilages of teleosts and their classification.

PubMed Central

Benjamin, M

1990-01-01

The structure and distribution of cartilages has been studied in 45 species from 24 families. The resulting data have been used as a basis for establishing a new classification. A cartilage is regarded as 'cell-rich' if its cells or their lacunae occupy more than half of the tissue volume. Five classes of cell-rich cartilage are recognised (a) hyaline-cell cartilage (common in the lips of bottom-dwelling cyprinids) and its subtypes fibro/hyaline-cell cartilage, elastic/hyaline-cell cartilage and lipo/hyaline-cell cartilage, (b) Schaffer's Zellknorpel, typified by the cartilage in the gill filaments of most teleosts examined, (c) elastic/cell-rich cartilage, such as that which supports the barbels and oral valves of catfish, e.g. Corydoras metae, (d) fibro/cell-rich cartilage, as in the submaxillary meniscus of Sphaerichthys osphromenoides, (e) cell-rich hyaline and (f) matrix-rich hyaline cartilage--both of which are common in the neurocranium and gill arches of most teleosts. The range of cartilages seen, and the predominant cartilage type, is recorded for each species and a list is provided of the tissues that most typify different organs or regions of the head. As a preliminary pointer to developmental relationships between the cartilages, note was taken of gradual transitions between one cartilage and another. It is suggested that hyaline-cell cartilage occupies a key position in teleosts as the most labile of the supporting tissues and is highly characteristic of Cypriniformes. The cartilage that best resembles mammalian hyaline cartilage (matrix-rich hyaline cartilage) has a very conservative distribution in different skeletal elements and the least number of associations with other tissues. It is well represented in Siluriformes. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 Fig. 24 Fig. 25 Fig. 26 Fig. 27 PMID:2384333

A ddRAD-based genetic map and its integration with the genome assembly of Japanese eel (Anguilla japonica) provides insights into genome evolution after the teleost-specific genome duplication.

PubMed

Kai, Wataru; Nomura, Kazuharu; Fujiwara, Atushi; Nakamura, Yoji; Yasuike, Motoshige; Ojima, Nobuhiko; Masaoka, Tetsuji; Ozaki, Akiyuki; Kazeto, Yukinori; Gen, Koichiro; Nagao, Jiro; Tanaka, Hideki; Kobayashi, Takanori; Ototake, Mitsuru

2014-03-26

Recent advancements in next-generation sequencing technology have enabled cost-effective sequencing of whole or partial genomes, permitting the discovery and characterization of molecular polymorphisms. Double-digest restriction-site associated DNA sequencing (ddRAD-seq) is a powerful and inexpensive approach to developing numerous single nucleotide polymorphism (SNP) markers and constructing a high-density genetic map. To enrich genomic resources for Japanese eel (Anguilla japonica), we constructed a ddRAD-based genetic map using an Ion Torrent Personal Genome Machine and anchored scaffolds of the current genome assembly to 19 linkage groups of the Japanese eel. Furthermore, we compared the Japanese eel genome with genomes of model fishes to infer the history of genome evolution after the teleost-specific genome duplication. We generated the ddRAD-based linkage map of the Japanese eel, where the maps for female and male spanned 1748.8 cM and 1294.5 cM, respectively, and were arranged into 19 linkage groups. A total of 2,672 SNP markers and 115 Simple Sequence Repeat markers provide anchor points to 1,252 scaffolds covering 151 Mb (13%) of the current genome assembly of the Japanese eel. Comparisons among the Japanese eel, medaka, zebrafish and spotted gar genomes showed highly conserved synteny among teleosts and revealed part of the eight major chromosomal rearrangement events that occurred soon after the teleost-specific genome duplication. The ddRAD-seq approach combined with the Ion Torrent Personal Genome Machine sequencing allowed us to conduct efficient and flexible SNP genotyping. The integration of the genetic map and the assembled sequence provides a valuable resource for fine mapping and positional cloning of quantitative trait loci associated with economically important traits and for investigating comparative genomics of the Japanese eel.

The nonlinear flexural response of a whole teleost fish: Contribution of scales and skin.

PubMed

Szewciw, Lawrence; Zhu, Deju; Barthelat, Francois

2017-12-01

The scaled skin of fish is an intricate system that provides mechanical protection against hard and sharp puncture, while maintaining the high flexural compliance required for unhindered locomotion. This unusual combination of local hardness and global compliance makes fish skin an interesting model for bioinspired protective systems. In this work we investigate the flexural response of whole teleost fish, and how scales may affect global flexural stiffness. A bending moment is imposed on the entire body of a striped bass (Morone saxatilis). Imaging is used to measure local curvature, to generate moment-curvature curves as function of position along the entire axis of the fish. We find that the flexural stiffness is the highest in the thick middle portion of the fish, and lowest in the caudal and rostral ends. The flexural response is nonlinear, with an initial soft response followed by significant stiffening at larger flexural deformations. Low flexural stiffness at low curvatures promotes efficient swimming, while higher stiffness at high curvatures enables a possible tendon effect, where the mechanical energy at the end of a stroke is stored in the form of strain energy in the fish skin. To assess the contribution of the scales to stiffening we performed flexural tests with and without scales, following a careful protocol to take in account tissue degradation and the effects of temperature. Our findings suggest that scales do not substantially increase the whole body flexural stiffness of teleost fish over ranges of deformations which are typical of swimming and maneuvering. Teleost scales are thin and relatively flexible, so they can accommodate large flexural deformations. This finding is in contrast to the bulkier ganoid scales which were shown in previous reports to have a profound impact of global flexural deformations and swimming in fish like gar or Polypterus. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular Cloning, Functional Characterization, and Evolutionary Analysis of Vitamin D Receptors Isolated from Basal Vertebrates

PubMed Central

Kollitz, Erin M.; Zhang, Guozhu; Hawkins, Mary Beth; Whitfield, G. Kerr; Reif, David M.; Kullman, Seth W.

2015-01-01

The vertebrate genome is a result of two rapid and successive rounds of whole genome duplication, referred to as 1R and 2R. Furthermore, teleost fish have undergone a third whole genome duplication (3R) specific to their lineage, resulting in the retention of multiple gene paralogs. The more recent 3R event in teleosts provides a unique opportunity to gain insight into how genes evolve through specific evolutionary processes. In this study we compare molecular activities of vitamin D receptors (VDR) from basal species that diverged at key points in vertebrate evolution in order to infer derived and ancestral VDR functions of teleost paralogs. Species include the sea lamprey (Petromyzon marinus), a 1R jawless fish; the little skate (Leucoraja erinacea), a cartilaginous fish that diverged after the 2R event; and the Senegal bichir (Polypterus senegalus), a primitive 2R ray-finned fish. Saturation binding assays and gel mobility shift assays demonstrate high affinity ligand binding and classic DNA binding characteristics of VDR has been conserved across vertebrate evolution. Concentration response curves in transient transfection assays reveal EC50 values in the low nanomolar range, however maximum transactivational efficacy varies significantly between receptor orthologs. Protein-protein interactions were investigated using co-transfection, mammalian 2-hybrid assays, and mutations of coregulator activation domains. We then combined these results with our previous study of VDR paralogs from 3R teleosts into a bioinformatics analysis. Our results suggest that 1, 25D3 acts as a partial agonist in basal species. Furthermore, our bioinformatics analysis suggests that functional differences between VDR orthologs and paralogs are influenced by differential protein interactions with essential coregulator proteins. We speculate that we may be observing a change in the pharmacodynamics relationship between VDR and 1, 25D3 throughout vertebrate evolution that may have been driven by changes in protein-protein interactions between VDR and essential coregulators. PMID:25855982

Embryonic and larval development in the Midas cichlid fish species flock (Amphilophus spp.): a new evo-devo model for the investigation of adaptive novelties and species differences.

PubMed

Kratochwil, Claudius F; Sefton, Maggie M; Meyer, Axel

2015-02-26

Central American crater lake cichlid fish of the Midas species complex (Amphilophus spp.) are a model system for sympatric speciation and fast ecological diversification and specialization. Midas cichlids have been intensively analyzed from an ecological and morphological perspective. Genomic resources such as transcriptomic and genomic data sets, and a high-quality draft genome are available now. Many ecologically relevant species-specific traits and differences such as pigmentation and cranial morphology arise during development. Detailed descriptions of the early development of the Midas cichlid in particular, will help to investigate the ontogeny of species differences and adaptations. We describe the embryonic and larval development of the crater lake cichlid, Amphilophus xiloaensis, until seven days after fertilization. Similar to previous studies on teleost development, we describe six periods of embryogenesis - the zygote, cleavage, blastula, gastrula, segmentation, and post-hatching period. Furthermore, we define homologous stages to well-described teleost models such as medaka and zebrafish, as well as other cichlid species such as the Nile tilapia and the South American cichlid Cichlasoma dimerus. Key morphological differences between the embryos of Midas cichlids and other teleosts are highlighted and discussed, including the presence of adhesive glands and different early chromatophore patterns, as well as variation in developmental timing. The developmental staging of the Midas cichlid will aid researchers in the comparative investigation of teleost ontogenies. It will facilitate comparative developmental biological studies of Neotropical and African cichlid fish in particular. In the past, the species flocks of the African Great Lakes have received the most attention from researchers, but some lineages of the 300-400 species of Central American lakes are fascinating model systems for adaptive radiation and rapid phenotypic evolution. The availability of genetic resources, their status as a model system for evolutionary research, and the possibility to perform functional experiments including transgenesis makes the Midas cichlid complex a very attractive model for evolutionary-developmental research.

Sensory Cells of the Fish Ear: A Hairy Enigma

NASA Technical Reports Server (NTRS)

Popper, A. N.; Saidel, W. M.

1995-01-01

Analysis of the structure of the ears in teleost fishes has led to the tentative suggestion that otolithic endorgans may function differently, in different species. Recently, evidence has demonstrated different 'types' of sensory hair cells can be found in the ears of teleost fishes, and individual hair cell types are found in discrete regions of individual sensory, epithelia. The presence of multiple hair cell types in fishes provides strong support to the hypothesis of regional differences in the responses of individual otolithic sensory epithelia. The finding of hair cell types in fishes that closely resemble those found in amniote vestibular endorgans also suggests that hair cell heterogeneity arose earlier in the evolution of the vertebrate ear than previously thought.

Plasmablasts and plasma cells: reconsidering teleost immune system organization.

PubMed

Ye, Jianmin; Kaattari, Ilsa; Kaattari, Stephen

2011-12-01

Comparative immunologists have expended extensive efforts in the characterization of early fish B cell development; however, analysis of the post-antigen induction stages of antibody secreting cell (ASC) differentiation has been limited. In contrast, work with murine ASCs has resolved the physically and functionally distinct cells known as plasmablasts, the short-lived plasma cells and long-lived plasma cells. Teleost ASCs are now known to also possess comparable subpopulations, which can greatly differ in such basic functions as lifespan, antigen sensitivity, antibody secretion rate, differentiative potential, and distribution within the body. Understanding the mechanisms by which these subpopulations are produced and distributed is essential for both basic understanding in comparative immunology and practical vaccine engineering. Copyright © 2011 Elsevier Ltd. All rights reserved.

Neuronal Organization of Deep Brain Opsin Photoreceptors in Adult Teleosts

PubMed Central

Hang, Chong Yee; Kitahashi, Takashi; Parhar, Ishwar S.

2016-01-01

Biological impacts of light beyond vision, i.e., non-visual functions of light, signify the need to better understand light detection (or photoreception) systems in vertebrates. Photopigments, which comprise light-absorbing chromophores bound to a variety of G-protein coupled receptor opsins, are responsible for visual and non-visual photoreception. Non-visual opsin photopigments in the retina of mammals and extra-retinal tissues of non-mammals play an important role in non-image-forming functions of light, e.g., biological rhythms and seasonal reproduction. This review highlights the role of opsin photoreceptors in the deep brain, which could involve conserved neurochemical systems that control different time- and light-dependent physiologies in in non-mammalian vertebrates including teleost fish. PMID:27199680

Long-term landscape change and bird abundance in Amazonian rainforest fragments.

PubMed

Stouffer, Philip C; Bierregaard, Richard O; Strong, Cheryl; Lovejoy, Thomas E

2006-08-01

The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km2/year leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1-100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist-netting program in 1- to 100-ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (< or =10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10- and 100-ha fragments connected to continuous forest by 20-year-old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into 'forest" and "nonforest" misses essential information about the matrix.

Amazonian phylogeography: mtDNA sequence variation in arboreal echimyid rodents (Caviomorpha).

PubMed

da Silva, M N; Patton, J L

1993-09-01

Patterns of evolutionary relationships among haplotype clades of sequences of the mitochondrial cytochrome b DNA gene are examined for five genera of arboreal rodents of the Caviomorph family Echimyidae from the Amazon Basin. Data are available for 798 bp of sequence from a total of 24 separate localities in Peru, Venezuela, Bolivia, and Brazil for Mesomys, Isothrix, Makalata, Dactylomys, and Echimys. Sequence divergence, corrected for multiple hits, is extensive, ranging from less than 1% for comparisons within populations of over 20% among geographic units within genera. Both the degree of differentiation and the geographic patterning of the variation suggest that more than one species composes the Amazonian distribution of the currently recognized Mesomys hispidus, Isothrix bistriata, Makalata didelphoides, and Dactylomys dactylinus. There is general concordance in the geographic range of haplotype clades for each of these taxa, and the overall level of differentiation within them is largely equivalent. These observations suggest that a common vicariant history underlies the respective diversification of each genus. However, estimated times of divergence based on the rate of third position transversion substitutions for the major clades within each genus typically range above 1 million years. Thus, allopatric isolation precipitating divergence must have been considerably earlier than the late Pleistocene forest fragmentation events commonly invoked for Amazonian biota.

Disease concepts and treatment by tribal healers of an Amazonian forest culture.

PubMed

Herndon, Christopher N; Uiterloo, Melvin; Uremaru, Amasina; Plotkin, Mark J; Emanuels-Smith, Gwendolyn; Jitan, Jeetendra

2009-10-12

The extensive medicinal plant knowledge of Amazonian tribal peoples is widely recognized in the scientific literature and celebrated in popular lore. Despite this broad interest, the ethnomedical systems and knowledge of disease which guide indigenous utilization of botanical diversity for healing remain poorly characterized and understood. No study, to our knowledge, has attempted to directly examine patterns of actual disease recognition and treatment by healers of an Amazonian indigenous culture. The establishment of traditional medicine clinics, operated and directed by elder tribal shamans in two remote Trio villages of the Suriname rainforest, presented a unique investigational opportunity. Quantitative analysis of clinic records from both villages permitted examination of diseases treated over a continuous period of four years. Cross-cultural comparative translations were articulated of recorded disease conditions through ethnographic interviews of elder Trio shamans and a comprehensive atlas of indigenous anatomical nomenclature was developed. 20,337 patient visits within the period 2000 to 2004 were analyzed. 75 disease conditions and 127 anatomical terms are presented. Trio concepts of disease and medical practices are broadly examined within the present and historical state of their culture. The findings of this investigation support the presence of a comprehensive and highly formalized ethnomedical institution within Trio culture with attendant health policy and conservation implications.

Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

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

Mayorga, E; Aufdenkampe, A K; Masiello, C A

2005-06-23

Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition ({sup 13}C andmore » {sup 14}C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than 5 years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in mid-size to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.« less

Amazonian Amphibian Diversity Is Primarily Derived from Late Miocene Andean Lineages

PubMed Central

Santos, Juan C; Coloma, Luis A; Summers, Kyle; Caldwell, Janalee P; Ree, Richard; Cannatella, David C

2009-01-01

The Neotropics contains half of remaining rainforests and Earth's largest reservoir of amphibian biodiversity. However, determinants of Neotropical biodiversity (i.e., vicariance, dispersals, extinctions, and radiations) earlier than the Quaternary are largely unstudied. Using a novel method of ancestral area reconstruction and relaxed Bayesian clock analyses, we reconstructed the biogeography of the poison frog clade (Dendrobatidae). We rejected an Amazonian center-of-origin in favor of a complex connectivity model expanding over the Neotropics. We inferred 14 dispersals into and 18 out of Amazonia to adjacent regions; the Andes were the major source of dispersals into Amazonia. We found three episodes of lineage dispersal with two interleaved periods of vicariant events between South and Central America. During the late Miocene, Amazonian, and Central American-Chocoan lineages significantly increased their diversity compared to the Andean and Guianan-Venezuelan-Brazilian Shield counterparts. Significant percentage of dendrobatid diversity in Amazonia and Chocó resulted from repeated immigrations, with radiations at <10.0 million years ago (MYA), rather than in situ diversification. In contrast, the Andes, Venezuelan Highlands, and Guiana Shield have undergone extended in situ diversification at near constant rate since the Oligocene. The effects of Miocene paleogeographic events on Neotropical diversification dynamics provided the framework under which Quaternary patterns of endemism evolved. PMID:19278298

Late Quaternary landscape evolution of northeastern Amazonia from pollen and diatom records.

PubMed

Castro, Darciléa F; De Oliveira, Paulo E; Rossetti, Dilce F; Pessenda, Luiz C R

2013-03-01

The main goal of this study was to reconstruct the Late Pleistocene-Holocene floristic composition in an area of the northern Brazilian Amazonia, comparing the results with other Amazonian localities in order to discuss the factors that have influenced phytophysiognomic changes over this time period. The work in eastern Marajó Island at the mouth of the Amazonas River was approached based on analysis of 98 pollen and diatom samples from core data distributed along a proximal to distal transect of a paleoestuarine system. The results indicated high concentration of Rhizophora, associated with arboreal pollen grains typical of the modern Amazonian rainforest during the last 40,000 cal yrs BP. Pollen composition also included wetland herbs. Diatoms were dominated by marine and fresh water taxa. Wetland forest, mangrove and, subordinately herbs remained constant during most of the latest Pleistocene-early/middle Holocene. At 5,000 cal yrs BP, there was a distinguished change from forest and mangrove to wet grassland savanna due to sea level fluctuation. As marine influence decreased, the estuary gave rise to fresh water lacustrine and swamp environments, with establishment of herbaceous campos. A main conclusion from this study is that solely the occurrence of herbaceous savanna can not be used as a definitive indicator of past dry climates in Amazonian areas.

Consistent, small effects of treefall disturbances on the composition and diversity of four Amazonian forests.

PubMed

Baker, Timothy R; Vela Díaz, Dilys M; Chama Moscoso, Victor; Navarro, Gilberto; Monteagudo, Abel; Pinto, Ruy; Cangani, Katia; Fyllas, Nikolaos M; Lopez Gonzalez, Gabriela; Laurance, William F; Lewis, Simon L; Lloyd, Jonathan; Ter Steege, Hans; Terborgh, John W; Phillips, Oliver L

2016-03-01

Understanding the resilience of moist tropical forests to treefall disturbance events is important for understanding the mechanisms that underlie species coexistence and for predicting the future composition of these ecosystems. Here, we test whether variation in the functional composition of Amazonian forests determines their resilience to disturbance.We studied the legacy of natural treefall disturbance events in four forests across Amazonia that differ substantially in functional composition. We compared the composition and diversity of all free-standing woody stems 2-10 cm diameter in previously disturbed and undisturbed 20 × 20 m subplots within 55, one-hectare, long-term forest inventory plots.Overall, stem number increased following disturbance, and species and functional composition shifted to favour light-wooded, small-seeded taxa. Alpha-diversity increased, but beta-diversity was unaffected by disturbance, in all four forests.Changes in response to disturbance in both functional composition and alpha-diversity were, however, small (2 - 4% depending on the parameter) and similar among forests. Synthesis . This study demonstrates that variation in the functional composition of Amazonian forests does not lead to large differences in the response of these forests to treefall disturbances, and overall, these events have a minor role in maintaining the diversity of these ecosystems.

Spatial trends in leaf size of Amazonian rainforest trees

NASA Astrophysics Data System (ADS)

Malhado, A. C. M.; Malhi, Y.; Whittaker, R. J.; Ladle, R. J.; Ter Steege, H.; Aragão, L. E. O. C.; Quesada, C. A.; Araujo-Murakami, A.; Phillips, O. L.; Peacock, J.; Lopez-Gonzalez, G.; Baker, T. R.; Butt, N.; Anderson, L. O.; Arroyo, L.; Almeida, S.; Higuchi, N.; Killeen, T. J.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R. P.; Silva, N.; Vásquez-Martínez, R.; Laurance, W. F.

2009-02-01

Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots (e.g. RAINFOR, ATDN) has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing south to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the results of the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that, as predicted, the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (>20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the north-west of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.

Spatial trends in leaf size of Amazonian rainforest trees

NASA Astrophysics Data System (ADS)

Malhado, A. C. M.; Malhi, Y.; Whittaker, R. J.; Ladle, R. J.; Ter Steege, H.; Phillips, O. L.; Butt, N.; Aragão, L. E. O. C.; Quesada, C. A.; Araujo-Murakami, A.; Arroyo, L.; Peacock, J.; Lopez-Gonzalez, G.; Baker, T. R.; Anderson, L. O.; Almeida, S.; Higuchi, N.; Killeen, T. J.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R. P.; Vásquez-Martínez, R.; Laurance, W. F.

2009-08-01

Leaf size influences many aspects of tree function such as rates of transpiration and photosynthesis and, consequently, often varies in a predictable way in response to environmental gradients. The recent development of pan-Amazonian databases based on permanent botanical plots has now made it possible to assess trends in leaf size across environmental gradients in Amazonia. Previous plot-based studies have shown that the community structure of Amazonian trees breaks down into at least two major ecological gradients corresponding with variations in soil fertility (decreasing from southwest to northeast) and length of the dry season (increasing from northwest to south and east). Here we describe the geographic distribution of leaf size categories based on 121 plots distributed across eight South American countries. We find that the Amazon forest is predominantly populated by tree species and individuals in the mesophyll size class (20.25-182.25 cm2). The geographic distribution of species and individuals with large leaves (>20.25 cm2) is complex but is generally characterized by a higher proportion of such trees in the northwest of the region. Spatially corrected regressions reveal weak correlations between the proportion of large-leaved species and metrics of water availability. We also find a significant negative relationship between leaf size and wood density.

Disease concepts and treatment by tribal healers of an Amazonian forest culture

PubMed Central

Herndon, Christopher N; Uiterloo, Melvin; Uremaru, Amasina; Plotkin, Mark J; Emanuels-Smith, Gwendolyn; Jitan, Jeetendra

2009-01-01

Background The extensive medicinal plant knowledge of Amazonian tribal peoples is widely recognized in the scientific literature and celebrated in popular lore. Despite this broad interest, the ethnomedical systems and knowledge of disease which guide indigenous utilization of botanical diversity for healing remain poorly characterized and understood. No study, to our knowledge, has attempted to directly examine patterns of actual disease recognition and treatment by healers of an Amazonian indigenous culture. Methods The establishment of traditional medicine clinics, operated and directed by elder tribal shamans in two remote Trio villages of the Suriname rainforest, presented a unique investigational opportunity. Quantitative analysis of clinic records from both villages permitted examination of diseases treated over a continuous period of four years. Cross-cultural comparative translations were articulated of recorded disease conditions through ethnographic interviews of elder Trio shamans and a comprehensive atlas of indigenous anatomical nomenclature was developed. Results 20,337 patient visits within the period 2000 to 2004 were analyzed. 75 disease conditions and 127 anatomical terms are presented. Trio concepts of disease and medical practices are broadly examined within the present and historical state of their culture. Conclusion The findings of this investigation support the presence of a comprehensive and highly formalized ethnomedical institution within Trio culture with attendant health policy and conservation implications. PMID:19821968

The synergistic use of models and observations: understanding the mechanisms behind observed biomass dynamics at 14 Amazonian field sites and the implications for future biomass change

NASA Astrophysics Data System (ADS)

Levine, N. M.; Galbraith, D.; Christoffersen, B. J.; Imbuzeiro, H. A.; Restrepo-Coupe, N.; Malhi, Y.; Saleska, S. R.; Costa, M. H.; Phillips, O.; Andrade, A.; Moorcroft, P. R.

2011-12-01

The Amazonian rainforests play a vital role in global water, energy and carbon cycling. The sensitivity of this system to natural and anthropogenic disturbances therefore has important implications for the global climate. Some global models have predicted large-scale forest dieback and the savannization of Amazonia over the next century [Meehl et al., 2007]. While several studies have demonstrated the sensitivity of dynamic global vegetation models to changes in temperature, precipitation, and dry season length [e.g. Galbraith et al., 2010; Good et al., 2011], the ability of these models to accurately reproduce ecosystem dynamics of present-day transitional or low biomass tropical forests has not been demonstrated. A model-data intercomparison was conducted with four state-of-the-art terrestrial ecosystem models to evaluate the ability of these models to accurately represent structure, function, and long-term biomass dynamics over a range of Amazonian ecosystems. Each modeling group conducted a series of simulations for 14 sites including mature forest, transitional forest, savannah, and agricultural/pasture sites. All models were run using standard physical parameters and the same initialization procedure. Model results were compared against forest inventory and dendrometer data in addition to flux tower measurements. While the models compared well against field observations for the mature forest sites, significant differences were observed between predicted and measured ecosystem structure and dynamics for the transitional forest and savannah sites. The length of the dry season and soil sand content were good predictors of model performance. In addition, for the big leaf models, model performance was highest for sites dominated by late successional trees and lowest for sites with predominantly early and mid-successional trees. This study provides insight into tropical forest function and sensitivity to environmental conditions that will aid in predictions of the response of the Amazonian rainforest to future anthropogenically induced changes.

Preservation of Late Amazonian Mars ice and water-related deposits in a unique crater environment in Noachis Terra: Age relationships between lobate debris tongues and gullies

NASA Astrophysics Data System (ADS)

Morgan, Gareth A.; Head, James W.; Marchant, David R.

2011-01-01

The Amazonian period of Mars has been described as static, cold, and dry. Recent analysis of high-resolution imagery of equatorial and mid-latitude regions has revealed an array of young landforms produced in association with ice and liquid water; because near-surface ice in these regions is currently unstable, these ice-and-water-related landforms suggest one or more episodes of martian climate change during the Amazonian. Here we report on the origin and evolution of valley systems within a degraded crater in Noachis Terra, Asimov Crater. The valleys have produced a unique environment in which to study the geomorphic signals of Amazonian climate change. New high-resolution images reveal Hesperian-aged layered basalt with distinctive columnar jointing capping interior crater fill and providing debris, via mass wasting, for the surrounding annular valleys. The occurrence of steep slopes (>20°), relatively narrow (sheltered) valleys, and a source of debris have provided favorable conditions for the preservation of shallow-ice deposits. Detailed mapping reveals morphological evidence for viscous ice flow, in the form of several lobate debris tongues (LDT). Superimposed on LDT are a series of fresh-appearing gullies, with typical alcove, channel, and fan morphologies. The shift from ice-rich viscous-flow formation to gully erosion is best explained as a shift in martian climate, from one compatible with excess snowfall and flow of ice-rich deposits, to one consistent with minor snow and gully formation. Available dating suggests that the climate transition occurred >8 Ma, prior to the formation of other small-scale ice-rich flow features identified elsewhere on Mars that have been interpreted to have formed during the most recent phases of high obliquity. Taken together, these older deposits suggest that multiple climatic shifts have occurred over the last tens of millions of years of martian history.

APW path traced for the Guiana Shield (2070-1960 Ma) and Paleogeographic Implications: Paleomagnetic data from the 1.98-1.96 Ga Surumu Group (Northern Amazonian Craton)

NASA Astrophysics Data System (ADS)

Bispo-Santos, F.; Dagrella Filho, M. S.; Reis, N. J.; Trindade, R. I.

2013-05-01

Definition of continental paleogeography for times prior to formation of Columbia Supercontinent (1900-1850 Ma) is very complex, since amalgamation of some continental blocks of Earth was still in progress, as in the case of Laurentia, Baltica and Amazonian Craton. So, paleogeographic models proposed for this time are still very speculative and/or subjective. The use of the paleomagnetic technique tracing apparent polar wander (APW) paths for the various cratonic blocks can contribute to understand the continental amalgamation and breakup, especially for times where all created oceanic lithosphere was fully consumed. In this study, we present the paleomagnetic data obtained for samples collected from 39 sites from the well-dated 1980-1960 Ma (U-Pb) volcanic rocks belonging to the Surumu Group, cropping out in the northern Roraima State (Guiana Shield, Amazonian Craton). AF and thermal treatment revealed northwestern directions with moderate downward inclinations on samples from 20 out of the 39 analyzed sites. Site mean directions cluster around the mean, Dm = 298.6°; Im = 39.4° (N = 20; α95 = 10.1°), which yielded a key paleomagnetic pole (SG) for the Guiana Shield, located at 234.8°E, 27.4°N (A95 = 9.8°). Magnetic mineralogy experiments show that the magnetization of these rocks, probably of primary origin, is carried by magnetite and/or hematite. The SG pole contributes to a better fit of the APW path traced for Guiana Shield during the Paleoproterozoic (2070-1960 Ma). Comparison with the APW path traced for the West-Africa Craton for the same time interval suggests that these cratonic blocks were linked at 2000-1960 Ma ago, forming a paleogeography in which the Guri (Guiana Shield) and Sassandra (West-Africa Craton) shear zones were aligned as suggested in previous geologic models. KEYWORDS: Paleoproterozoic, Paleomagnetism, APWP, Amazonian Craton, Surumu Group.

The Fate of Amazonian Ecosystems over the Coming Century Arising from Changes in Climate, Atmospheric CO2 and Land-use

NASA Astrophysics Data System (ADS)

Moorcroft, P. R.; Zhang, K.; Castanho, A. D. D. A.; Galbraith, D.; Moghim, S.; Levine, N. M.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Malhi, Y.; Longo, M.; Knox, R. G.; McKnight, S. L.; Wang, J.

2014-12-01

There is considerable interest and uncertainty regarding the expected fate of the Amazon over the coming century in face of the combined impacts of climate change, rising atmospheric CO2 levels, and on-going land transformation in the region. In this analysis, we explore the fate of Amazonian ecosystems under projected climate, CO2 and land-use change in the 21st century using three state-of-the-art terrestrial biosphere models (ED2, IBIS, and JULES) driven by three representative, bias-corrected GCM climate projections (PCM1, CCSM3, and HadCM3) under the SRES A2 scenario, coupled with two land-use change scenarios. We assess the relative roles of climate change, CO2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change depend strongly on the direction and severity of projected changes in precipitation regimes within the region: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%; however, the models predict that CO2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and as a result sustain high biomass forests, even under the driest climate scenario. Land-use change and changes in fire frequency are predicted cause additional aboveground live biomass loss and changes in forest extent. The relative impact of land-use and fire dynamics versus the impacts of climate and CO2 on the Amazon varies considerably, depending on both the climate and land-use scenarios used and on the terrestrial biosphere model, highlighting the importance of improved understanding of all four factors -- future climate, CO2 fertilization effects, fire and land-use -- to the fate of the Amazon over the coming century.

High diversity of tropical peatland ecosystem types in the Pastaza-Marañón basin, Peruvian Amazonia

NASA Astrophysics Data System (ADS)

LäHteenoja, Outi; Page, Susan

2011-06-01

Very little information exists on Amazonian peatlands with most studies on tropical peatlands concentrating on Southeast Asia. Here we describe diversity of Amazonian peatland ecosystems and consider its implications for the global diversity of tropical peatland ecosystems. Nine study sites were selected from within the most extensive wetland area of Peruvian Amazonia: the 120,000 km2 Pastaza-Marañón basin. Peat thickness was determined every 500 m from the edge toward the center of each site, and peat samples were collected from two cores per site. Samples from the entire central core and surface samples from the other core were analyzed for nutrient content. Topography of four peat deposits was measured. In order to study differences in vegetation, pixel values were extracted from a satellite image. The surface peat nutrient content of the peatlands varied from very nutrient-rich to nutrient-poor. Two of the peatlands measured for their topography were domed (5.4 and 5.8 m above the stream), one was gently sloping (1.4 m above the stream), and one was flat and occurred behind a 7 m high levee. Five different peatland vegetation types were detected on the basis of pixel values derived from the satellite image. The peat cores had considerable variation in nutrient content and showed different developmental pathways. In summary, the Pastaza-Marañón basin harbors a considerable diversity of previously undescribed peatland ecosystems, representing a gradient from atmosphere-influenced, nutrient-poor ombrotrophic bogs through to river-influenced, nutrient-rich swamps. Their existence affects the habitat diversity, carbon dynamics, and hydrology of the Amazonian lowlands, and they also provide an undisturbed analog for the heavily disturbed peatlands of Southeast Asia. Considering the factors threatening the Amazonian lowlands, there is an urgent need to investigate and conserve these peatland ecosystems, which may in the near future be among the very few undisturbed tropical ombrotrophic bogs remaining in the world.

Tropical small streams are a consistent source of methane

NASA Astrophysics Data System (ADS)

Vihermaa, Leena; Waldron, Susan

2013-04-01

To date only a few studies have quantified diffusive methane emissions from headwater streams therefore the magnitude and seasonal variation of these emissions remain poorly understood. Here we present results from two Western Amazonian small streams (first and second order) in Tambopata National Reserve, Peru. Towards the end of wet season, April-May 2012, the streams were sampled using a static floating chamber to accumulate methane. Samples were drawn from the headspace twice daily over period of four days on three separate occasions. The methane concentrations were analysed using a gas chromatograph and the linear part of concentration increase used to calculate the flux rates. The streams were consistently outgassing methane. The seasonally active first order stream outgassed 6 ±2.4 nmol CH4-C m-2 s-1 and the second order stream 20 ±4.0 nmol CH4-C m-2 s-1. The latter flux rate is comparable to fluxes measured from seasonally flooded Amazonian forest in previous studies. The range measured in our streams is comparable to previous results in temperate streams and the lower end of fluxes observed in some peatland streams. The only other study on Amazonian small streams detected methane fluxes that were 100 times greater than those measured here. Depending on the density of small streams in Amazonian basin and the prevalent flux rate, the fluvial methane fluxes may constitute a significant global warming potential. Upscaling to the Amazon basin, assuming small stream density of 0.2 %, as was found at our field site, and the flux rates detected, yields an annual global warming potential equal to approximately 1.5 Mt of CO2 which is of minor importance compared to aquatic CO2-C flux of 500 Mt yr-1 from the basin. However, if the higher fluxes detected in the previous study were prevalent, the basin wide methane flux could become significant. Further studies are needed to establish the stream density in the Amazon basin and typical methane flux rates.

Primary centers and secondary concentrations of tectonic activity through time in the western hemisphere of Mars

USGS Publications Warehouse

Anderson, R.C.; Dohm, J.M.; Golombek, M.P.; Haldemann, A.F.C.; Franklin, B.J.; Tanaka, K.L.; Lias, J.; Peer, B.

2001-01-01

Five main stages of radial and concentric structures formed around Tharsis from the Noachian through the Amazonian as determined by geologic mapping of 24,452 structures within the stratigraphic framework of Mars and by testing their radial and concentric orientations. Tectonic activity peaked in the Noachian (stage 1) around the largest center, Claritas, an elongate center extending more than 20?? in latitude and defined by about half of the total grabens which are concentrated in the Syria Planum, Thaumasia, and Tempe Terra regions. During the Late Noachian and Early Hesperian (stage 2), extensional structures formed along the length of present-day Valles Marineris and in Thaumasia (with a secondary concentration near Warrego Vallis) radial to a region just to the south of the central margin of Valles Marineris. Early Hesperian (stage 3) radial grabens in Pavonis, Syria, Ulysses, and Tempe Terra and somewhat concentric wrinkle ridges in Lunae and Solis Plana and in Thaumasia, Sirenum, Memnonia, and Amazonis are centered northwest of Syria with secondary centers at Thaumasia, Tempe Terra, Ulysses Fossae, and western Valles Marineris. Late Hesperian/Early Amazonian (stage 4) structures around Alba Patera, the northeast trending alignment of Tharsis Montes, and Olympus Mons appears centered on Alba Patera. Stage 5 structures (Middle-Late Amazonian) represent the last pulse of Tharsis-related activity and are found around the large shield volcanoes and are centered near Pavonis Mons. Tectonic activity around Tharsis began in the Noachian and generally decreased through geologic time to the Amazonian. Statistically significant radial distributions of structures formed during each stage, centered at different locations within the higher elevations of Tharsis. Secondary centers of radial structures during many of the stages appear related to previously identified local magmatic centers that formed at different times and locations throughout Tharsis. Copyright 2001 by the American Geophysical Union.

Diversity and physiological characterization of D-xylose-fermenting yeasts isolated from the Brazilian Amazonian Forest.

PubMed

Cadete, Raquel M; Melo, Monaliza A; Dussán, Kelly J; Rodrigues, Rita C L B; Silva, Silvio S; Zilli, Jerri E; Vital, Marcos J S; Gomes, Fátima C O; Lachance, Marc-André; Rosa, Carlos A

2012-01-01

This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L) culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g) and productivities (0.62 g/L · h to 0.75 g/L · h). Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g), with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g) and productivity (0.2 g/L · h), while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates.

Ecosystem state shifts during long-term development of an Amazonian peatland.

PubMed

Swindles, Graeme T; Morris, Paul J; Whitney, Bronwen; Galloway, Jennifer M; Gałka, Mariusz; Gallego-Sala, Angela; Macumber, Andrew L; Mullan, Donal; Smith, Mark W; Amesbury, Matthew J; Roland, Thomas P; Sanei, Hamed; Patterson, R Timothy; Sanderson, Nicole; Parry, Lauren; Charman, Dan J; Lopez, Omar; Valderamma, Elvis; Watson, Elizabeth J; Ivanovic, Ruza F; Valdes, Paul J; Turner, T Edward; Lähteenoja, Outi

2018-02-01

The most carbon (C)-dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long-term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6-6.1 and ca. 4.9-3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland-forest swamp-peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8-1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Mercury in fish from the Madeira River and health risk to Amazonian and riverine populations.

PubMed

Soares, José Maria; Gomes, José M; Anjos, Marcelo R; Silveira, Josianne N; Custódio, Flavia B; Gloria, M Beatriz A

2018-07-01

The objective of this study was to quantify total mercury in highly popular Amazonian fish pacu, curimatã, jaraqui, and sardinha from the Madeira River and to estimate the exposure to methylmercury from fish consumption. The samples were obtained from two locations - Puruzinho Igarapé and Santa Rosa - near Humaitá, Amazonia, Brazil in two seasons of 2015 (high and low waters). The fish were identified, weighed and measured, and lipids were quantified. Total mercury was determined by gold amalgamation-atomic absorption spectrometry. Mean levels were used to calculate exposure of Amazonian and riverine populations. There was significant correlation (p < 0.05) between length × weight for all fish; length × lipid and weight × lipid were significant only for pacu. Total mercury levels varied along muscle tissue for the fish, except for sardinha; therefore muscle from the dorsal area along the fish were sampled, homogenized and used for analysis. The levels of total mercury varied from 0.01 to 0.46 mg/kg, with higher median levels in sardinha (0.24 mg/kg), followed by curimatã (0.16 mg/kg), jaraqui (0.13 mg/kg) and pacu (0.04 mg/kg), corresponding with the respective feeding habits along the trophic chain. Total mercury levels were not affected by the location of fish capture and by high and low waters seasons. Total mercury correlated significantly with length and weight for jaraqui and with length for sardinha (negative correlation). Total mercury levels in fish complied with legislation; however, exposures to methylmercury from fish consumption overpassed the safe intake reference dose for sardinha for Amazonians; however, for the riverine communities, all of the fish would cause potential health risk, mainly for children and women of childbearing age. Copyright © 2018 Elsevier Ltd. All rights reserved.

Water transport and functional dynamics of aquaporins in osmoregulatory organs of fishes.

PubMed

Madsen, Steffen S; Engelund, Morten B; Cutler, Christopher P

2015-08-01

Aquaporins play distinct roles for water transport in fishes as they do in mammals-both at the cellular, organ, and organismal levels. However, with over 32,000 known species of fishes inhabiting almost every aquatic environment, from tidal pools, small mountain streams, to the oceans and extreme salty desert lakes, the challenge to obtain consensus as well as specific knowledge about aquaporin physiology in these vertebrate clades is overwhelming. Because the integumental surfaces of these animals are in intimate contact with the surrounding milieu, passive water loss and uptake represent two of the major osmoregulatory challenges that need compensation. However, neither obligatory nor regulatory water transport nor their mechanisms have been elucidated to the same degree as, for example, ion transport in fishes. Currently fewer than 60 papers address fish aquaporins. Most of these papers identify "what is present" and describe tissue expression patterns in various teleosts. The agnathans, chondrichthyans, and functionality of fish aquaporins generally have received little attention. This review emphasizes the functional physiology of aquaporins in fishes, focusing on transepithelial water transport in osmoregulatory organs in euryhaline species - primarily teleosts, but covering other taxonomic groups as well. Most current knowledge comes from teleosts, and there is a strong need for related information on older fish clades. Our survey aims to stimulate new, original research in this area and to bring together new collaborations across disciplines. © 2015 Marine Biological Laboratory.

Distinct Differentiation Programs Triggered by IL-6 and LPS in Teleost IgM(+) B Cells in The Absence of Germinal Centers.

PubMed

Abós, Beatriz; Wang, Tiehui; Castro, Rosario; Granja, Aitor G; Leal, Esther; Havixbeck, Jeffrey; Luque, Alfonso; Barreda, Daniel R; Secombes, Chris J; Tafalla, Carolina

2016-08-02

Although originally identified as a B cell differentiation factor, it is now known that mammalian interleukin-6 (IL-6) only regulates B cells committed to plasma cells in response to T-dependent (TD) antigens within germinal centers (GCs). Even though adaptive immunity is present in teleost fish, these species lack lymph nodes and GCs. Thus, the aim of the present study was to establish the role of trout IL-6 on B cells, comparing its effects to those induced by bacterial lipopolysaccharide (LPS). We demonstrate that the effects of teleost IL-6 on naïve spleen B cells include proliferation, activation of NF-κB, increased IgM secretion, up-regulation of Blimp1 transcription and decreased MHC-II surface expression that point to trout IL-6 as a differentiation factor for IgM antibody-secreting cells (ASCs). However, LPS induced the secretion of IgM without up-regulating Blimp1, driving the cells towards an intermediate activation state in which antigen presenting mechanisms are elicited together with antibody secretion and expression of pro-inflammatory genes. Our results reveal that, in trout, IL-6 is a differentiation factor for B cells, stimulating IgM responses in the absence of follicular structures, and suggest that it was after follicular structures appeared that this cytokine evolved to modulate TD responses within the GC.

Stress and sex: does cortisol mediate sex change in fish?

PubMed

Goikoetxea, Alexander; Todd, Erica V; Gemmell, Neil J

2017-12-01

Cortisol is the main glucocorticoid (GC) in fish and the hormone most directly associated with stress. Recent research suggests that this hormone may act as a key factor linking social environmental stimuli and the onset of sex change by initiating a shift in steroidogenesis from estrogens to androgens. For many teleost fish, sex change occurs as a usual part of the life cycle. Changing sex is known to enhance the lifetime reproductive success of these fish and the modifications involved (behavioral, gonadal and morphological) are well studied. However, the exact mechanism behind the transduction of the environmental signals into the molecular cascade that underlies this singular process remains largely unknown. We here synthesize current knowledge regarding the role of cortisol in teleost sex change with a focus on two well-described transformations: temperature-induced masculinization and socially regulated sex change. Three non-mutually exclusive pathways are considered when describing the potential role of cortisol in mediating teleost sex change: cross-talk between GC and androgen pathways, inhibition of aromatase expression and upregulation of amh (the gene encoding anti-Müllerian hormone). We anticipate that understanding the role of cortisol in the initial stages of sex change will further improve our understanding of sex determination and differentiation across vertebrates, and may lead to new tools to control fish sex ratios in aquaculture. © 2017 Society for Reproduction and Fertility.

Alternative Pre-mRNA Splicing in Mammals and Teleost Fish: A Effective Strategy for the Regulation of Immune Responses Against Pathogen Infection.

PubMed

Chang, Ming Xian; Zhang, Jie

2017-07-15

Pre-mRNA splicing is the process by which introns are removed and the protein coding elements assembled into mature mRNAs. Alternative pre-mRNA splicing provides an important source of transcriptome and proteome complexity through selectively joining different coding elements to form mRNAs, which encode proteins with similar or distinct functions. In mammals, previous studies have shown the role of alternative splicing in regulating the function of the immune system, especially in the regulation of T-cell activation and function. As lower vertebrates, teleost fish mainly rely on a large family of pattern recognition receptors (PRRs) to recognize pathogen-associated molecular patterns (PAMPs) from various invading pathogens. In this review, we summarize recent advances in our understanding of alternative splicing of piscine PRRs including peptidoglycan recognition proteins (PGRPs), nucleotide binding and oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) and their downstream signaling molecules, compared to splicing in mammals. We also discuss what is known and unknown about the function of splicing isoforms in the innate immune responses against pathogens infection in mammals and teleost fish. Finally, we highlight the consequences of alternative splicing in the innate immune system and give our view of important directions for future studies.

The evolution of vertebrate somatostatin receptors and their gene regions involves extensive chromosomal rearrangements

PubMed Central

2012-01-01

Background Somatostatin and its related neuroendocrine peptides have a wide variety of physiological functions that are mediated by five somatostatin receptors with gene names SSTR1-5 in mammals. To resolve their evolution in vertebrates we have investigated the SSTR genes and a large number of adjacent gene families by phylogeny and conserved synteny analyses in a broad range of vertebrate species. Results We find that the SSTRs form two families that belong to distinct paralogons. We observe not only chromosomal similarities reflecting the paralogy relationships between the SSTR-bearing chromosome regions, but also extensive rearrangements between these regions in teleost fish genomes, including fusions and translocations followed by reshuffling through intrachromosomal rearrangements. These events obscure the paralogy relationships but are still tractable thanks to the many genomes now available. We have identified a previously unrecognized SSTR subtype, SSTR6, previously misidentified as either SSTR1 or SSTR4. Conclusions Two ancestral SSTR-bearing chromosome regions were duplicated in the two basal vertebrate tetraploidizations (2R). One of these ancestral SSTR genes generated SSTR2, -3 and -5, the other gave rise to SSTR1, -4 and -6. Subsequently SSTR6 was lost in tetrapods and SSTR4 in teleosts. Our study shows that extensive chromosomal rearrangements have taken place between related chromosome regions in teleosts, but that these events can be resolved by investigating several distantly related species. PMID:23194088

Multi-locus phylogenetic analysis reveals the pattern and tempo of bony fish evolution

PubMed Central

Broughton, Richard E.; Betancur-R., Ricardo; Li, Chenhong; Arratia, Gloria; Ortí, Guillermo

2013-01-01

Over half of all vertebrates are “fishes”, which exhibit enormous diversity in morphology, physiology, behavior, reproductive biology, and ecology. Investigation of fundamental areas of vertebrate biology depend critically on a robust phylogeny of fishes, yet evolutionary relationships among the major actinopterygian and sarcopterygian lineages have not been conclusively resolved. Although a consensus phylogeny of teleosts has been emerging recently, it has been based on analyses of various subsets of actinopterygian taxa, but not on a full sample of all bony fishes. Here we conducted a comprehensive phylogenetic study on a broad taxonomic sample of 61 actinopterygian and sarcopterygian lineages (with a chondrichthyan outgroup) using a molecular data set of 21 independent loci. These data yielded a resolved phylogenetic hypothesis for extant Osteichthyes, including 1) reciprocally monophyletic Sarcopterygii and Actinopterygii, as currently understood, with polypteriforms as the first diverging lineage within Actinopterygii; 2) a monophyletic group containing gars and bowfin (= Holostei) as sister group to teleosts; and 3) the earliest diverging lineage among teleosts being Elopomorpha, rather than Osteoglossomorpha. Relaxed-clock dating analysis employing a set of 24 newly applied fossil calibrations reveals divergence times that are more consistent with paleontological estimates than previous studies. Establishing a new phylogenetic pattern with accurate divergence dates for bony fishes illustrates several areas where the fossil record is incomplete and provides critical new insights on diversification of this important vertebrate group. PMID:23788273

hebp3, a novel member of the heme-binding protein gene family, is expressed in the medaka meninges with higher abundance in females due to a direct stimulating action of ovarian estrogens.

PubMed

Nakasone, Kiyoshi; Nagahama, Yoshitaka; Okubo, Kataaki

2013-02-01

The brains of teleost fish exhibit remarkable sexual plasticity throughout their life span. To dissect the molecular basis for the development and reversal of sex differences in the teleost brain, we screened for genes differentially expressed between sexes in the brain of medaka (Oryzias latipes). One of the genes identified in the screen as being preferentially expressed in females was found to be a new member of the heme-binding protein gene family that includes hebp1 and hebp2 and was designated here as hebp3. The medaka hebp3 is expressed in the meninges with higher abundance in females, whereas there is no expression within the brain parenchyma. This female-biased expression of hebp3 is not attributable to the direct action of sex chromosome genes but results from the transient and reversible action of estrogens derived from the ovary. Moreover, estrogens directly activate the transcription of hebp3 via a palindromic estrogen-responsive element in the hebp3 promoter. Taken together, our findings demonstrate that hebp3 is a novel transcriptional target of estrogens, with female-biased expression in the meninges. The definite but reversible sexual dimorphism of the meningeal hebp3 expression may contribute to the development and reversal of sex differences in the teleost brain.

The Caudal Skeleton of the Zebrafish, Danio rerio, from a Phylogenetic Perspective: A Polyural Interpretation of Homologous Structures

PubMed Central

Wiley, Edward O.; Fuiten, Allison M.; Doosey, Michael H.; Lohman, Brian K.; Merkes, Christopher; Azuma, Mizuki

2016-01-01

The structure of the caudal skeleton of extant teleost fishes has been interpreted in two different ways. In a diural interpretation, a caudal skeleton is composed of two centra articulated with one to six hypurals. Most subsequent authors have followed this interpretation. In contrast, a polyural interpretation considers the teleost fin to be derived from a fully metameristic ancestral bauplan originally composed of a one-to-one relationship between neural arches, centra (when present), and hypurals. Three different interpretations of the identity and homology of skeletal components of the caudal skeleton of the teleost fish Danio rerio have been proposed, two from a diural perspective and one from a polyural perspective. We examine each caudal skeletal component of Danio rerio from both a developmental and phylogenetic perspective. We propose that a polyural interpretation of structures is consistent with the current interpretation of the basal neopterygian caudal fin for this model organism rather than the older diural interpretation that does not take into account the metamerism observed in caudal structures during development. The polyural interpretation suggests several shared evolutionary innovations of major clades that would remain undiscovered under the older diural naming paradigm and makes the terminology of the parts of the caudal fin of Danio rerio strictly comparable to more basal fishes. PMID:28250540

Polyvalent cation receptor proteins (CaRs) are salinity sensors in fish.

PubMed

Nearing, J; Betka, M; Quinn, S; Hentschel, H; Elger, M; Baum, M; Bai, M; Chattopadyhay, N; Brown, E M; Hebert, S C; Harris, H W

2002-07-09

To determine whether calcium polyvalent cation-sensing receptors (CaRs) are salinity sensors in fish, we used a homology-based cloning strategy to isolate a 4.1-kb cDNA encoding a 1,027-aa dogfish shark (Squalus acanthias) kidney CaR. Expression studies in human embryonic kidney cells reveal that shark kidney senses combinations of Ca(2+), Mg(2+), and Na(+) ions at concentrations present in seawater and kidney tubules. Shark kidney is expressed in multiple shark osmoregulatory organs, including specific tubules of the kidney, rectal gland, stomach, intestine, olfactory lamellae, gill, and brain. Reverse transcriptase-PCR amplification using specific primers in two teleost fish, winter flounder (Pleuronectes americanus) and Atlantic salmon (Salmo salar), reveals a similar pattern of CaR tissue expression. Exposure of the lumen of winter flounder urinary bladder to the CaR agonists, Gd(3+) and neomycin, reversibly inhibit volume transport, which is important for euryhaline teleost survival in seawater. Within 24-72 hr after transfer of freshwater-adapted Atlantic salmon to seawater, there are increases in their plasma Ca(2+), Mg(2+), and Na(+) that likely serve as a signal for internal CaRs, i.e., brain, to sense alterations in salinity in the surrounding water. We conclude that CaRs act as salinity sensors in both teleost and elasmobranch fish. Their tissue expression patterns in fish provide insights into CaR functions in terrestrial animals including humans.

Corticosteroid receptor expression in a teleost fish that displays alternative male reproductive tactics.

PubMed

Arterbery, Adam S; Deitcher, David L; Bass, Andrew H

2010-01-01

Corticosteroid signaling mechanisms mediate a wide range of adaptive physiological responses, including those essential to reproduction. Here, we investigated the presence and relative abundance of corticosteroid receptors during the breeding season in the plainfin midshipman fish (Porichthys notatus), a species that has two male reproductive morphs. Only type I "singing" males acoustically court females and aggressively defend a nest site, whereas type II "sneaker" males steal fertilizations from nesting type I males. Cloning and sequencing first identified glucocorticoid (GR) and mineralocorticoid (MR) receptors in midshipman that exhibited high sequence identity with other vertebrate GRs and MRs. Absolute-quantitative real-time PCR then revealed higher levels of GR in the central nervous system (CNS) of type II males than type I males and females, while GR levels in the sound-producing, vocal muscle and the liver were higher in type I males than type II males and females. MR expression was also greater in the CNS of type II males than type I males or females, but the differences were more modest in magnitude. Lastly, plasma levels of cortisol, the main glucocorticoid in teleosts, were 2- to 3-fold greater in type II males compared to type I males. Together, the results suggest a link between corticosteroid regulation and physiological and behavioral variation in a teleost fish that displays male alternative reproductive tactics.

Amazonian mid- to high-latitude glaciation on Mars: Supply-limited ice sources, ice accumulation patterns, and concentric crater fill glacial flow and ice sequestration

NASA Astrophysics Data System (ADS)

Fastook, James L.; Head, James W.

2014-02-01

Concentric crater fill (CCF) occurs in the interior of impact craters in mid- to high latitudes on Mars and is interpreted to have formed by glacial ice flow and debris covering. We use the characteristics and orientation of deposits comprising CCF, the thickness of pedestal deposits in mid- to high-latitude pedestal craters (Pd), the volumes of the current polar caps, and information about regional slopes and ice rheology to address questions about (1) the maximum thickness of regional ice deposits during the Late Amazonian, (2) the likelihood that these deposits flowed regionally, (3) the geological regions and features most likely to induce ice-flow, and (4) the locations and environments in which ice is likely to have been sequestered up to the present. We find that regional ice flow under Late Amazonian climate conditions requires ice thicknesses exceeding many hundreds of meters for slopes typical of the vast majority of the surface of Mars, a thickness for the mid-latitudes that is well in excess of the total volume available from polar ice reservoirs. This indicates that although conditions for mid- to high-latitude glaciation may have persisted for tens to hundreds of millions of years, the process is “supply limited”, with a steady state reached when the polar ice cap water ice supply becomes exhausted. Impact craters are by far the most abundant landform with associated slopes (interior wall and exterior rim) sufficiently high to induce glacial ice flow under Late Amazonian climate conditions, and topographic slope data show that Amazonian impact craters have been clearly modified, undergoing crater interior slope reduction and floor shallowing. We show that these trends are the predictable response of ice deposition and preferential accumulation and retention in mid- to high-latitude crater interiors during episodes of enhanced spin-axis obliquity. We demonstrate that flow from a single episode of an inter-crater terrain layer comparable to Pedestal Crater deposit thicknesses (~50 m) cannot fill the craters in a time period compatible with the interpreted formation times of the Pedestal Crater mantled ice layers. We use a representative obliquity solution to drive an ice flow model and show that a cyclical pattern of multiply recurring layers can both fill the craters with a significant volume of ice, as well as transport debris from the crater walls out into the central regions of the craters. The cyclical pattern of waxing and waning mantling layers results in a rippled pattern of surface debris extending out into the crater interiors that would manifest itself as an observable concentric pattern, comparable in appearance to concentric crater fill. In this scenario, the formation of mantling sublimation till layers seals the accumulating ice and sequesters it from significant temperature variations at diurnal, annual and spin-axis/orbital cycle time scales, to produce ancient ice records preserved today below CCF crater floors. Lack of meltwater features associated with concentric crater fill provides evidence that the Late Amazonian climate did not exceed the melting temperature in the mid- to high-latitudes for any significant period of time. Continued sequestration of ice with time in CCF and related deposits (lobate debris aprons and lineated valley fill) further reduces the already supply-limited polar ice sources, suggesting that there has been a declining reservoir of available ice with each ensuing glacial period. Together, these deposits represent a candidate library of climate chemistry and global change dating from the Late Amazonian, and a non-polar water resource for future exploration.

Model gives a 3-month warning of Amazonian forest fires

NASA Astrophysics Data System (ADS)

Schultz, Colin

2011-08-01

The widespread drought suffered by the Amazon rain forest in the summer of 2005 was heralded at the time as the drought of the century. Because of the dehydrated conditions, supplemented by slash and burn agricultural practices, the drought led to widespread forest fires throughout the western Amazon, a portion of the rain forest usually too lush to support spreading wildfires. Only 5 years later, the 2005 season was outdone by even more widespread drought, with fires decimating more than 3000 square kilometers of western Amazonian rain forest. Blame for the wildfires has been consistently laid on deforestation and agricultural practices, but a convincing climatological explanation exists as well. (Geophysical Research Letters, doi:10.1029/2011GL047392, 2011)

Updating the Evidence for Oceans on Early Mars

NASA Technical Reports Server (NTRS)

Fairen, Alberto G.; Dohm, James M.; Oner, Tayfun; Ruiz, Javier; Rodriguez, Alexis P.; Schulze-Makuch, Dirk; Ormoe, Jens; McKay, Chris P.; Baker, Victor R.; Amils, Ricardo

2004-01-01

Different-sized bodies of water have been proposed to have occurred episodically in the lowlands of Mars throughout the planet's history, largely related to major stages of development of Tharsis and/or orbital obliquity. These water bodies range from large oceans in the Noachian-Early Hesperian, to a minor sea in the Late Hesperian, and dispersed lakes during the Amazonian. To evaluate the more recent discoveries regarding the oceanic possibility, here we perform a comprehensive analysis of the evolution of water on Mars, including: 1. Geological assessment of proposed shorelines; 2. A volumetric approximation to the plains-filing proposed oceans; 3. Geochemistry of the oceans and derived mineralogies; 4. Post-oceanic (i.e., Amazonian) evolution of the shorelines; and 5. Ultimate water evolution on Mars.

Fast demographic traits promote high diversification rates of Amazonian trees

PubMed Central

Baker, Timothy R; Pennington, R Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J M M; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Brienen, Roel J W; Chave, Jerome; Dexter, Kyle G; Di Fiore, Anthony; Eler, Eduardo; Feldpausch, Ted R; Ferreira, Leandro; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje; Higuchi, Niro; Honorio, Eurídice; Huamantupa, Isau; Killeen, Tim J; Laurance, Susan; Leaño, Claudio; Lewis, Simon L; Malhi, Yadvinder; Marimon, Beatriz Schwantes; Marimon Junior, Ben Hur; Monteagudo Mendoza, Abel; Neill, David; Peñuela-Mora, Maria Cristina; Pitman, Nigel; Prieto, Adriana; Quesada, Carlos A; Ramírez, Fredy; Ramírez Angulo, Hirma; Rudas, Agustin; Ruschel, Ademir R; Salomão, Rafael P; de Andrade, Ana Segalin; Silva, J Natalino M; Silveira, Marcos; Simon, Marcelo F; Spironello, Wilson; ter Steege, Hans; Terborgh, John; Toledo, Marisol; Torres-Lezama, Armando; Vasquez, Rodolfo; Vieira, Ima Célia Guimarães; Vilanova, Emilio; Vos, Vincent A; Phillips, Oliver L; Wiens, John

2014-01-01

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits – short turnover times – are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests. PMID:24589190

A marvelous new glassfrog (Centrolenidae, Hyalinobatrachium) from Amazonian Ecuador.

PubMed

Guayasamin, Juan M; Cisneros-Heredia, Diego F; Maynard, Ross J; Lynch, Ryan L; Culebras, Jaime; Hamilton, Paul S

2017-01-01

Hyalinobatrachium is a behaviorally and morphologically conserved genus of Neotropical anurans, with several pending taxonomic problems. Using morphology, vocalizations, and DNA, a new species from the Amazonian lowlands of Ecuador is described and illustrated. The new species, Hyalinobatrachium yaku sp. n. , is differentiated from all other congenerics by having small, middorsal, dark green spots on the head and dorsum, a transparent pericardium, and a tonal call that lasts 0.27-0.4 s, with a dominant frequency of 5219.3-5329.6 Hz. Also, a mitochondrial phylogeny for the genus is presented that contains the new species, which is inferred as sister to H. pellucidum . Conservation threats to H. yaku sp. n. include habitat destruction and/or pollution mainly because of oil and mining activities.

Helminths of the teiid lizard Kentropyx calcarata (Squamata) from an Amazonian site in western Brazil.

PubMed

Avila, R W; da Silva, R J

2009-09-01

Despite being conspicuous members of neotropical lizard communities, aspects of the life history of many teiid lizard species are poorly known, especially endoparasites infecting the genus Kentropyx. We studied seven specimens of K. calcarata collected at an Amazonian site in Mato Grosso state, Central Brazil in 2007. Four species of helminth were recovered: Oswaldocruzia sp., Piratuba digiticauda, Physaloptera retusa and Physalopteroides venancioi. Piratuba digiticauda, a body-cavity, parasite had the highest prevalence (42.9%), whereas the stomach parasites P. venancioi and P. retusa presented the highest intensity of infection and abundance, respectively. Moreover, this is the first report of Oswaldocruzia sp., P. digiticauda and P. venancioi in K. calcarata and new locality records for all nematodes were assigned.

Basal teleosts and the question of elopomorph monophyly. Morphological and molecular approaches.

PubMed

Filleul, A; Lavoué, S

2001-04-01

The methodology used by previous authors to resolve the relationships of the elopomorphan taxa is criticized. The morphological characters that have been proposed to support the monophyly of the Elopomorpha are reviewed and it is shown that most of them are weak. A new hypothesis of relationships is proposed on the basis of nucleotidic sequences of ribosomal RNA 18S, 16S and 12S. In order to really test all the possible relationships, the monophyly of the Elopomorpha was not considered a priori. The tree was rooted on Amia calva and Lepisosteus osseus and the ingroup taxa sampling was subsequently increased. The obtained topology shows that the Elopomorpha is a non-monophyletic taxon. Elopiforms, anguilliforms, albuliforms and notacanthiforms are considered here as four monophyletic, incertae sedis taxa among basal teleosts.

Phylogeny of immunoglobulin structure and function. VII. Monomeric and tetrameric immunoglobulins of the margate, a marine teleost fish.

PubMed Central

Clem, L W; McLean, W E

1975-01-01

The margate, a marine teleost fish, was found to contain both high (16S) and low (7S) molecular weight antibodies 17 days after initial immunization. The 16S antibodies were detectable with both haemagglutination and antigen-binding assays, whereas the 7S antibodies were only detected by the latter technique. Margate 16S (molecular weight approximately 700,000) and 7S (molecular weight approximately 175,000) immunoglobulins were isolated and shown to be antigenically indistinguishable. They therefore appear to belong to the same immunoglobulin class and to have a tetramer--monomer relationship. Experiments with stored sera indicated the 7S protein is probably not an in vitro degradation product of the 16S molecule. Images FIG. 3 FIG. 4 PMID:1184121

Length and sequence variability in mitochondrial control region of the milkfish, Chanos chanos.

PubMed

Ravago, Rachel G; Monje, Virginia D; Juinio-Meñez, Marie Antonette

2002-01-01

Extensive length variability was observed in the mitochondrial control region of the milkfish, Chanos chanos. The nucleotide sequence of the control region and flanking regions was determined. Length variability and heteroplasmy was due to the presence of varying numbers of a 41-bp tandemly repeated sequence and a 48-bp insertion/deletion (indel). The structure and organization of the milkfish control region is similar to that of other teleost fish and vertebrates. However, extensive variation in the copy number of tandem repeats (4-20 copies) and the presence of a relatively large (48-bp) indel, are apparently uncommon in teleost fish control region sequences reported to date. High sequence variability of control region peripheral domains indicates the potential utility of selected regions as markers for population-level studies.

Comparative transcriptomics of elasmobranchs and teleosts highlight important processes in adaptive immunity and regional endothermy.

PubMed

Marra, Nicholas J; Richards, Vincent P; Early, Angela; Bogdanowicz, Steve M; Pavinski Bitar, Paulina D; Stanhope, Michael J; Shivji, Mahmood S

2017-01-30

Comparative genomic and/or transcriptomic analyses involving elasmobranchs remain limited, with genome level comparisons of the elasmobranch immune system to that of higher vertebrates, non-existent. This paper reports a comparative RNA-seq analysis of heart tissue from seven species, including four elasmobranchs and three teleosts, focusing on immunity, but concomitantly seeking to identify genetic similarities shared by the two lamnid sharks and the single billfish in our study, which could be linked to convergent evolution of regional endothermy. Across seven species, we identified an average of 10,877 Swiss-Prot annotated genes from an average of 32,474 open reading frames within each species' heart transcriptome. About half of these genes were shared between all species while the remainder included functional differences between our groups of interest (elasmobranch vs. teleost and endotherms vs. ectotherms) as revealed by Gene Ontology (GO) and selection analyses. A repeatedly represented functional category, in both the uniquely expressed elasmobranch genes (total of 259) and the elasmobranch GO enrichment results, involved antibody-mediated immunity, either in the recruitment of immune cells (Fc receptors) or in antigen presentation, including such terms as "antigen processing and presentation of exogenous peptide antigen via MHC class II", and such genes as MHC class II, HLA-DPB1. Molecular adaptation analyses identified three genes in elasmobranchs with a history of positive selection, including legumain (LGMN), a gene with roles in both innate and adaptive immunity including producing antigens for presentation by MHC class II. Comparisons between the endothermic and ectothermic species revealed an enrichment of GO terms associated with cardiac muscle contraction in endotherms, with 19 genes expressed solely in endotherms, several of which have significant roles in lipid and fat metabolism. This collective comparative evidence provides the first multi-taxa transcriptomic-based perspective on differences between elasmobranchs and teleosts, and suggests various unique features associated with the adaptive immune system of elasmobranchs, pointing in particular to the potential importance of MHC Class II. This in turn suggests that expanded comparative work involving additional tissues, as well as genome sequencing of multiple elasmobranch species would be productive in elucidating the regulatory and genome architectural hallmarks of elasmobranchs.

Systematics of the Dendropsophus leucophyllatus species complex (Anura: Hylidae): Cryptic diversity and the description of two new species

PubMed Central

Caminer, Marcel A.; Milá, Borja; Jansen, Martin; Fouquet, Antoine; Venegas, Pablo J.; Chávez, Germán; Lougheed, Stephen C.

2017-01-01

Genetic data in studies of systematics of Amazonian amphibians frequently reveal that purportedly widespread single species in reality comprise species complexes. This means that real species richness may be significantly higher than current estimates. Here we combine genetic, morphological, and bioacoustic data to assess the phylogenetic relationships and species boundaries of two Amazonian species of the Dendropsophus leucophyllatus species group: D. leucophyllatus and D. triangulum. Our results uncovered the existence of five confirmed and four unconfirmed candidate species. Among the confirmed candidate species, three have available names: Dendropsophus leucophyllatus, Dendropsophus triangulum, and Dendropsophus reticulatus, this last being removed from the synonymy of D. triangulum. A neotype of D. leucophyllatus is designated. We describe the remaining two confirmed candidate species, one from Bolivia and another from Peru. All confirmed candidate species are morphologically distinct and have much smaller geographic ranges than those previously reported for D. leucophyllatus and D. triangulum sensu lato. Dendropsophus leucophyllatus sensu stricto occurs in the Guianan region. Dendropsophus reticulatus comb. nov. corresponds to populations in the Amazon basin of Brazil, Ecuador, and Peru previously referred to as D. triangulum. Dendropsophus triangulum sensu stricto is the most widely distributed species; it occurs in Amazonian Ecuador, Peru and Brazil, reaching the state of Pará. We provide accounts for all described species including an assessment of their conservation status. PMID:28248998

A free-access online key to identify Amazonian ferns.

PubMed

Zuquim, Gabriela; Tuomisto, Hanna; Prado, Jefferson

2017-01-01

There is urgent need for more data on species distributions in order to improve conservation planning. A crucial but challenging aspect of producing high-quality data is the correct identification of organisms. Traditional printed floras and dichotomous keys are difficult to use for someone not familiar with the technical jargon. In poorly known areas, such as Amazonia, they also become quickly outdated as new species are described or ranges extended. Recently, online tools have allowed developing dynamic, interactive, and accessible keys that make species identification possible for a broader public. In order to facilitate identifying plants collected in field inventories, we developed an internet-based free-access tool to identify Amazonian fern species. We focused on ferns, because they are easy to collect and their edaphic affinities are relatively well known, so they can be used as an indicator group for habitat mapping. Our key includes 302 terrestrial and aquatic entities mainly from lowland Amazonian forests. It is a free-access key, so the user can freely choose which morphological features to use and in which order to assess them. All taxa are richly illustrated, so specimens can be identified by a combination of character choices, visual comparison, and written descriptions. The identification tool was developed in Lucid 3.5 software and it is available at http://keyserver.lucidcentral.org:8080/sandbox/keys.jsp.

The Genetic History of Peruvian Quechua‐Lamistas and Chankas: Uniparental DNA Patterns among Autochthonous Amazonian and Andean Populations

PubMed Central

Sandoval, José R.; Lacerda, Daniela R.; Acosta, Oscar; Jota, Marilza S.; Robles‐Ruiz, Paulo; Salazar‐Granara, Alberto; Vieira, Pedro Paulo R.; Paz‐y‐Miño, César; Fujita, Ricardo

2016-01-01

Summary This study focuses on the genetic history of the Quechua‐Lamistas, inhabitants of the Lamas Province in the San Martin Department, Peru, who speak their own distinct variety of the Quechua family of languages. It has been suggested that different pre‐Columbian ethnic groups from the Peruvian Amazonia, like the Motilones or “shaven heads”, assimilated the Quechua language and then formed the current native population of Lamas. However, many Quechua‐Lamistas claim to be direct descendants of the Chankas, a famous pre‐Columbian indigenous group that escaped from Inca rule in the Andes. To investigate the Quechua‐Lamistas and Chankas’ ancestries, we compared uniparental genetic profiles (17 STRs of Q‐M3 Y‐chromosome and mtDNA complete control region haplotypes) among autochthonous Amazonian and Andean populations from Peru, Bolivia and Ecuador. The phylogeographic and population genetic analyses indicate a fairly heterogeneous ancestry for the Quechua‐Lamistas, while they are closely related to their neighbours who speak Amazonian languages, presenting no direct relationships with populations from the region where the ancient Chankas lived. On the other hand, the genetic profiles of self‐identified Chanka descendants living in Andahuaylas (located in the Apurimac Department, Peru, in the Central Andes) were closely related to those living in Huancavelica and the assumed Chanka Confederation area before the Inca expansion. PMID:26879156

Land use intensity trajectories on Amazonian pastures derived from Landsat time series

NASA Astrophysics Data System (ADS)

Rufin, Philippe; Müller, Hannes; Pflugmacher, Dirk; Hostert, Patrick

2015-09-01

Monitoring changes in land use intensity of grazing systems in the Amazon is an important prerequisite to study the complex political and socio-economic forces driving Amazonian deforestation. Remote sensing offers the potential to map pasture vegetation over large areas, but mapping pasture conditions consistently through time is not a trivial task because of seasonal changes associated with phenology and data gaps from clouds and cloud shadows. In this study, we tested spectral-temporal metrics derived from intra-annual Landsat time series to distinguish between grass-dominated and woody pastures. The abundance of woody vegetation on pastures is an indicator for management intensity, since the duration and intensity of land use steer secondary succession rates, apart from climate and soil conditions. We used the developed Landsat-based metrics to analyze pasture intensity trajectories between 1985 and 2012 in Novo Progresso, Brazil, finding that woody vegetation cover generally decreased after four to ten years of grazing activity. Pastures established in the 80s and early 90s showed a higher fraction of woody vegetation during their initial land use history than pastures established in the early 2000s. Historic intensity trajectories suggested a trend towards more intensive land use in the last decade, which aligns well with regional environmental policies and market dynamics. This study demonstrates the potential of dense Landsat time series to monitor land-use intensification on Amazonian pastures.

Riverscape genetics identifies replicated ecological divergence across an Amazonian ecotone.

PubMed

Cooke, Georgina M; Landguth, Erin L; Beheregaray, Luciano B

2014-07-01

Ecological speciation involves the evolution of reproductive isolation and niche divergence in the absence of a physical barrier to gene flow. The process is one of the most controversial topics of the speciation debate, particularly in tropical regions. Here, we investigate ecologically based divergence across an Amazonian ecotone in the electric fish, Steatogenys elegans. We combine phylogenetics, genome scans, and population genetics with a recently developed individual-based evolutionary landscape genetics approach that incorporates selection. This framework is used to assess the relative contributions of geography and divergent natural selection between environments as biodiversity drivers. We report on two closely related and sympatric lineages that exemplify how divergent selection across a major Amazonian aquatic ecotone (i.e., between rivers with markedly different hydrochemical properties) may result in replicated ecologically mediated speciation. The results link selection across an ecological gradient with reproductive isolation and we propose that assortative mating based on water color may be driving the divergence. Divergence resulting from ecologically driven selection highlights the importance of considering environmental heterogeneity in studies of speciation in tropical regions. Furthermore, we show that framing ecological speciation in a spatially explicit evolutionary landscape genetics framework provides an important first step in exploring a wide range of the potential effects of spatial dependence in natural selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Soil transmitted helminthiasis in indigenous groups. A community cross sectional study in the Amazonian southern border region of Ecuador.

PubMed

Romero-Sandoval, Natalia; Ortiz-Rico, Claudia; Sánchez-Pérez, Héctor Javier; Valdivieso, Daniel; Sandoval, Carlos; Pástor, Jacob; Martín, Miguel

2017-03-14

Rural communities in the Amazonian southern border of Ecuador have benefited from governmental social programmes over the past 9 years, which have addressed, among other things, diseases associated with poverty, such as soil transmitted helminth infections. The aim of this study was to explore the prevalence of geohelminth infection and several factors associated with it in these communities. This was a cross sectional study in two indigenous communities of the Amazonian southern border of Ecuador. The data were analysed at both the household and individual levels. At the individual level, the prevalence of geohelminth infection reached 46.9% (95% CI 39.5% to 54.2%), with no differences in terms of gender, age, temporary migration movements or previous chemoprophylaxis. In 72.9% of households, one or more members were infected. Receiving subsidies and overcrowding were associated with the presence of helminths. The prevalence of geohelminth infection was high. Our study suggests that it is necessary to conduct studies focusing on communities, and not simply on captive groups, such as schoolchildren, with the object of proposing more suitable and effective strategies to control this problem. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

A free-access online key to identify Amazonian ferns

PubMed Central

Zuquim, Gabriela; Tuomisto, Hanna; Prado, Jefferson

2017-01-01

Abstract There is urgent need for more data on species distributions in order to improve conservation planning. A crucial but challenging aspect of producing high-quality data is the correct identification of organisms. Traditional printed floras and dichotomous keys are difficult to use for someone not familiar with the technical jargon. In poorly known areas, such as Amazonia, they also become quickly outdated as new species are described or ranges extended. Recently, online tools have allowed developing dynamic, interactive, and accessible keys that make species identification possible for a broader public. In order to facilitate identifying plants collected in field inventories, we developed an internet-based free-access tool to identify Amazonian fern species. We focused on ferns, because they are easy to collect and their edaphic affinities are relatively well known, so they can be used as an indicator group for habitat mapping. Our key includes 302 terrestrial and aquatic entities mainly from lowland Amazonian forests. It is a free-access key, so the user can freely choose which morphological features to use and in which order to assess them. All taxa are richly illustrated, so specimens can be identified by a combination of character choices, visual comparison, and written descriptions. The identification tool was developed in Lucid 3.5 software and it is available at http://keyserver.lucidcentral.org:8080/sandbox/keys.jsp. PMID:28781548

A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry

PubMed Central

Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Claude, Julien; Antoine, Pierre-Olivier

2016-01-01

Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region. PMID:27097031

Geographical origin of Amazonian freshwater fishes fingerprinted by ⁸⁷Sr/⁸⁶Sr ratios on fish otoliths and scales.

PubMed

Pouilly, Marc; Point, David; Sondag, Francis; Henry, Manuel; Santos, Roberto V

2014-08-19

Calcified structures such as otoliths and scales grow continuously throughout the lifetime of fishes. The geochemical variations present in these biogenic structures are particularly relevant for studying fish migration and origin. In order to investigate the potential of the (87)Sr/(86)Sr ratio as a precise biogeochemical tag in Amazonian fishes, we compared this ratio between the water and fish otoliths and scales of two commercial fish species, Hoplias malabaricus and Schizodon fasciatus, from three major drainage basins of the Amazon: the Madeira, Solimões, and Tapajós rivers, displaying contrasted (87)Sr/(86)Sr ratios. A comparison of the (87)Sr/(86)Sr ratios between the otoliths and scales of the same individuals revealed similar values and were very close to the Sr isotopic composition of the local river where they were captured. This indicates, first, the absence of Sr isotopic fractionation during biological uptake and incorporation into calcified structures and, second, that scales may represent an interesting nonlethal alternative for (87)Sr/(86)Sr ratio measurements in comparison to otoliths. Considering the wide range of (87)Sr/(86)Sr variations that exist across Amazonian rivers, we used variations of (87)Sr/(86)Sr to discriminate fish origin at the basin level, as well as at the sub-basin level between the river and savannah lakes of the Beni River (Madeira basin).

The Genetic History of Peruvian Quechua-Lamistas and Chankas: Uniparental DNA Patterns among Autochthonous Amazonian and Andean Populations.

PubMed

Sandoval, José R; Lacerda, Daniela R; Acosta, Oscar; Jota, Marilza S; Robles-Ruiz, Paulo; Salazar-Granara, Alberto; Vieira, Pedro Paulo R; Paz-Y-Miño, César; Fujita, Ricardo; Santos, Fabricio R

2016-03-01

This study focuses on the genetic history of the Quechua-Lamistas, inhabitants of the Lamas Province in the San Martin Department, Peru, who speak their own distinct variety of the Quechua family of languages. It has been suggested that different pre-Columbian ethnic groups from the Peruvian Amazonia, like the Motilones or "shaven heads", assimilated the Quechua language and then formed the current native population of Lamas. However, many Quechua-Lamistas claim to be direct descendants of the Chankas, a famous pre-Columbian indigenous group that escaped from Inca rule in the Andes. To investigate the Quechua-Lamistas and Chankas' ancestries, we compared uniparental genetic profiles (17 STRs of Q-M3 Y-chromosome and mtDNA complete control region haplotypes) among autochthonous Amazonian and Andean populations from Peru, Bolivia and Ecuador. The phylogeographic and population genetic analyses indicate a fairly heterogeneous ancestry for the Quechua-Lamistas, while they are closely related to their neighbours who speak Amazonian languages, presenting no direct relationships with populations from the region where the ancient Chankas lived. On the other hand, the genetic profiles of self-identified Chanka descendants living in Andahuaylas (located in the Apurimac Department, Peru, in the Central Andes) were closely related to those living in Huancavelica and the assumed Chanka Confederation area before the Inca expansion. © 2016 John Wiley & Sons Ltd/University College London.

Thermal physiology of Amazonian lizards (Reptilia: Squamata)

PubMed Central

Caetano, Gabriel H. O.; Pontes, Emerson; Ávila-Pires, Teresa C. S.

2018-01-01

We summarize thermal-biology data of 69 species of Amazonian lizards, including mode of thermoregulation and field-active body temperatures (Tb). We also provide new data on preferred temperatures (Tpref), voluntary and thermal-tolerance ranges, and thermal-performance curves (TPC’s) for 27 species from nine sites in the Brazilian Amazonia. We tested for phylogenetic signal and pairwise correlations among thermal traits. We found that species generally categorized as thermoregulators have the highest mean values for all thermal traits, and broader ranges for Tb, critical thermal maximum (CTmax) and optimal (Topt) temperatures. Species generally categorized as thermoconformers have large ranges for Tpref, critical thermal minimum (CTmin), and minimum voluntary (VTmin) temperatures for performance. Despite these differences, our results show that all thermal characteristics overlap between both groups and suggest that Amazonian lizards do not fit into discrete thermoregulatory categories. The traits are all correlated, with the exceptions of (1) Topt, which does not correlate with CTmax, and (2) CTmin, and correlates only with Topt. Weak phylogenetic signals for Tb, Tpref and VTmin indicate that these characters may be shaped by local environmental conditions and influenced by phylogeny. We found that open-habitat species perform well under present environmental conditions, without experiencing detectable thermal stress from high environmental temperatures induced in lab experiments. For forest-dwelling lizards, we expect warming trends in Amazonia to induce thermal stress, as temperatures surpass the thermal tolerances for these species. PMID:29513695

Using Ecological Niche Models and Niche Analyses to Understand Speciation Patterns: The Case of Sister Neotropical Orchid Bees

PubMed Central

Silva, Daniel P.; Vilela, Bruno; De Marco, Paulo; Nemésio, André

2014-01-01

The role of past connections between the two major South American forested biomes on current species distribution has been recognized a long time ago. Climatic oscillations that further separated these biomes have promoted parapatric speciation, in which many species had their continuous distribution split, giving rise to different but related species (i.e., different potential distributions and realized niche features). The distribution of many sister species of orchid bees follow this pattern. Here, using ecological niche models and niche analyses, we (1) tested the role of ecological niche differentiation on the divergence between sister orchid-bees (genera Eulaema and Eufriesea) from the Amazon and Atlantic forests, and (2) highlighted interesting areas for new surveys. Amazonian species occupied different realized niches than their Atlantic sister species. Conversely, species of sympatric but distantly related Eulaema bees occupied similar realized niches. Amazonian species had a wide potential distribution in South America, whereas Atlantic Forest species were more limited to the eastern coast of the continent. Additionally, we identified several areas in need of future surveys. Our results show that the realized niche of Atlantic-Amazonian sister species of orchid bees, which have been previously treated as allopatric populations of three species, had limited niche overlap and similarity. These findings agree with their current taxonomy, which treats each of those populations as distinct valid species. PMID:25422941

A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry.

PubMed

Salas-Gismondi, Rodolfo; Flynn, John J; Baby, Patrice; Tejada-Lara, Julia V; Claude, Julien; Antoine, Pierre-Olivier

2016-01-01

Gavialoid crocodylians are the archetypal longirostrine archosaurs and, as such, understanding their patterns of evolution is fundamental to recognizing cranial rearrangements and reconstructing adaptive pathways associated with elongation of the rostrum (longirostry). The living Indian gharial Gavialis gangeticus is the sole survivor of the group, thus providing unique evidence on the distinctive biology of its fossil kin. Yet phylogenetic relationships and evolutionary ecology spanning ~70 million-years of longirostrine crocodylian diversification remain unclear. Analysis of cranial anatomy of a new proto-Amazonian gavialoid, Gryposuchus pachakamue sp. nov., from the Miocene lakes and swamps of the Pebas Mega-Wetland System reveals that acquisition of both widely separated and protruding eyes (telescoped orbits) and riverine ecology within South American and Indian gavialoids is the result of parallel evolution. Phylogenetic and morphometric analyses show that, in association with longirostry, circumorbital bone configuration can evolve rapidly for coping with trends in environmental conditions and may reflect shifts in feeding strategy. Our results support a long-term radiation of the South American forms, with taxa occupying either extreme of the gavialoid morphospace showing preferences for coastal marine versus fluvial environments. The early biogeographic history of South American gavialoids was strongly linked to the northward drainage system connecting proto-Amazonian wetlands to the Caribbean region.

Altered resource availability and the population dynamics of tree species in Amazonian secondary forests.

PubMed

Fortini, Lucas Berio; Bruna, Emilio M; Zarin, Daniel J; Vasconcelos, Steel S; Miranda, Izildinha S

2010-04-01

Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species-Lacistema pubescens and Myrcia sylvatica-in dry-season irrigation, litter-removal and control plots. We then evaluated the effects of altered water and nutrient availability on population demography and dynamics using matrix models and life table response experiments. Our results show that despite prolonged experimental manipulation of water and nutrient availability, there were nearly no consistent and unidirectional treatment effects on the demography of either species. The patterns and significance of observed treatment effects were largely dependent on cross-year variability not related to rainfall patterns, and disappeared once we pooled data across years. Furthermore, most of these transient treatment effects had little effect on population growth rates. Our results suggest that despite major experimental manipulations of water and nutrient availability-factors considered critical to the ecology of tropical pioneer tree species-autogenic light limitation appears to be the primary regulator of tree demography at early/mid successional stages. Indeed, the effects of light availability may completely override those of other factors thought to influence the successional development of Amazonian secondary forests.

Falling palm fronds structure amazonian rainforest sapling communities.

PubMed

Peters, Halton A; Pauw, Anton; Silman, Miles R; Terborgh, John W

2004-08-07

The senescence and loss of photosynthetic and support structures is a nearly universal aspect of tree life history, and can be a major source of disturbance in forest understoreys, but the ability of falling canopy debris in determining the stature and composition of understorey communities seems not to have been documented. In this study, we show that senescent fronds of the palm Iriartea deltoidea cause substantial disturbance in tropical forest sapling communities. This disturbance influences the species composition of the canopy and subcanopy by acting as an ecological filter, favouring sapling species with characteristics conducive to recovery after physical damage. The scale of this dominance suggests that falling I. deltoidea debris may be influencing sapling community structure and species composition in Amazonian rainforests over very large spatial scales.

Mars Climate History: Insights From Impact Crater Wall Slope Statistics

NASA Astrophysics Data System (ADS)

Kreslavsky, Mikhail A.; Head, James W.

2018-02-01

We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.

Mars Global Geologic Mapping: Amazonian Results

NASA Technical Reports Server (NTRS)

Tanaka, K. L.; Dohm, J. M.; Irwin, R.; Kolb, E. J.; Skinner, J. A., Jr.; Hare, T. M.

2008-01-01

We are in the second year of a five-year effort to map the geology of Mars using mainly Mars Global Surveyor, Mars Express, and Mars Odyssey imaging and altimetry datasets. Previously, we have reported on details of project management, mapping datasets (local and regional), initial and anticipated mapping approaches, and tactics of map unit delineation and description [1-2]. For example, we have seen how the multiple types and huge quantity of image data as well as more accurate and detailed altimetry data now available allow for broader and deeper geologic perspectives, based largely on improved landform perception, characterization, and analysis. Here, we describe early mapping results, which include updating of previous northern plains mapping [3], including delineation of mainly Amazonian units and regional fault mapping, as well as other advances.

A marvelous new glassfrog (Centrolenidae, Hyalinobatrachium) from Amazonian Ecuador

PubMed Central

Guayasamin, Juan M.; Cisneros-Heredia, Diego F.; Maynard, Ross J.; Lynch, Ryan L.; Culebras, Jaime; Hamilton, Paul S.

2017-01-01

Abstract Hyalinobatrachium is a behaviorally and morphologically conserved genus of Neotropical anurans, with several pending taxonomic problems. Using morphology, vocalizations, and DNA, a new species from the Amazonian lowlands of Ecuador is described and illustrated. The new species, Hyalinobatrachium yaku sp. n., is differentiated from all other congenerics by having small, middorsal, dark green spots on the head and dorsum, a transparent pericardium, and a tonal call that lasts 0.27–0.4 s, with a dominant frequency of 5219.3–5329.6 Hz. Also, a mitochondrial phylogeny for the genus is presented that contains the new species, which is inferred as sister to H. pellucidum. Conservation threats to H. yaku sp. n. include habitat destruction and/or pollution mainly because of oil and mining activities. PMID:28769670

Multiple, novel biologically active endophytic actinomycetes isolated from upper Amazonian rainforests.

PubMed

Bascom-Slack, Carol A; Ma, Cong; Moore, Emily; Babbs, Beatrice; Fenn, Kathleen; Greene, Joshua S; Hann, Bradley D; Keehner, Jocelyn; Kelley-Swift, Elizabeth G; Kembaiyan, Vivek; Lee, Sun Jin; Li, Puyao; Light, David Y; Lin, Emily H; Schorn, Michelle A; Vekhter, Daniel; Boulanger, Lori-Ann; Hess, W M; Vargas, Percy Núñez; Strobel, Gary A; Strobel, Scott A

2009-08-01

Microbial biodiversity provides an increasingly important source of medically and industrially useful compounds. We have isolated 14 actinomycete species from a collection of approximately 300 plant stem samples from the upper Amazonian rainforest in Peru. All of the cultured isolates produce substances with inhibitory activity directed at a range of potential fungal and bacterial pathogens. For some organisms, this activity is very broad in spectrum while other organisms show specific activity against a limited number of organisms. Two of these organisms preferentially inhibit bacterial test organisms over eukaryotic organisms. rDNA sequence analysis indicates that these organisms are not equivalent to any other cultured deposits in GenBank. Our results provide evidence of the untapped biodiversity in the form of biologically active microbes present within the tissues of higher plants.

Evidence for stabilization of the ice-cemented cryosphere in earlier martian history: Implications for the current abundance of groundwater at depth on Mars

NASA Astrophysics Data System (ADS)

Weiss, David K.; Head, James W.

2017-05-01

The present-day martian mean annual surface temperature is well below freezing at all latitudes; this produces a near-surface portion of the crust that is below the freezing point of water for > 2 consecutive years (defined as permafrost). This permafrost layer (i.e., the cryosphere) is a few to tens of km thick depending on latitude. Below the base of the permafrost (i.e., the cryosphere), groundwater is stable if it exists, and can increase and decrease in abundance as the freezing isotherm rises and falls. Where water is available, ice fills the pore space within the cryosphere; this region is known as the ice-cemented cryosphere (ICC). The potential for a large reservoir of pore ice beneath the surface has been the subject of much discussion: previous studies have demonstrated that the theoretical thickness of the martian cryosphere in the Amazonian period ranges from up to ∼9 km at the equator to ∼10-22 km at the poles. The total thickness of ice that might fill the pore space within the cryosphere (the ICC), however, remains unknown. A class of martian crater, the Hesperian-Amazonian-aged single-layered ejecta crater, is widely accepted as having formed by impact into an ice-cemented target. Although the target structure related to the larger multiple-layered ejecta craters remains uncertain, they have recently been interpreted to be formed by impact crater excavation below the ice-cemented target, and here we tentatively adopt this interpretation in order to infer the thickness of the ice-cemented cryosphere. Our global examination of the excavation depths of these crater populations points to a Hesperian-Amazonian-aged ice-cemented cryosphere that is ∼1.3 km thick at the equator, and ∼2.3 km thick at the poles (corresponding to a global equivalent water layer of ∼200 m assuming ∼20% pore ice at the surface). To explore the implications of this result on the martian climatic and hydrologic evolution, we then assess the surface temperature, atmospheric pressure, obliquity, and surface heat flux conditions under which the downward-propagating cryosphere freezing front matches the inferred ice-cemented cryosphere. The thermal models which can best reproduce the inferred ice-cemented cryosphere occur for obliquities between 25° and 45° and CO2 atmospheric pressures ≤600 mbar, but require increased heat fluxes and surface temperatures/pressures relative to the Amazonian period. Because the inferred ice-cemented cryosphere is much thinner compared with Amazonian-aged cryosphere thermal models, we suggest that the ice-cemented cryosphere ceased growing when it exhausted the underlying groundwater supply (i.e., ICC stabilization) in a more ancient period in Mars geologic history. Our thermal analysis suggests that this ICC stabilization likely occurred sometime before or at ∼3.0-3.3 Ga (during or before the Late Hesperian or Early Amazonian period). If groundwater remained below the ICC during the earlier Late Noachian period, our models predict that mean annual surface temperatures during this time were ≥212-227 K. If the Late Noachian had a pure CO2 atmosphere, this places a minimum bound on the Late Noachian atmospheric pressure of ≥390-850 mbar. These models suggest that deep groundwater is not abundant or does not persist in the subsurface of Mars today, and that diffusive loss of ice from the subsurface has been minimal.

A fossil unicorn crestfish (Teleostei, Lampridiformes, Lophotidae) from the Eocene of Iran.

PubMed

Davesne, Donald

2017-01-01

Lophotidae, or crestfishes, is a family of rare deep-sea teleosts characterised by an enlarged horn-like crest on the forehead. They are poorly represented in the fossil record, by only three described taxa. One specimen attributed to Lophotidae has been described from the pelagic fauna of the middle-late Eocene Zagros Basin, Iran. Originally considered as a specimen of the fossil lophotid † Protolophotus , it is proposed hereby as a new genus and species † Babelichthys olneyi , gen. et sp. nov., differs from the other fossil lophotids by its relatively long and strongly projecting crest, suggesting a close relationship with the modern unicorn crestfish, Eumecichthys . This new taxon increases the diversity of the deep-sea teleost fauna to which it belongs, improving our understanding of the taxonomic composition of the early Cenozoic mesopelagic ecosystems.

Stomach contents of cetaceans incidentally caught along Mangalore and Chennai coasts of India

NASA Astrophysics Data System (ADS)

Krishnan, Anoop A.; Yousuf, K. S.; Kumaran, P. L.; Harish, N.; Anoop, B.; Afsal, V. V.; Rajagopalan, M.; Vivekanandan, E.; Krishnakumar, P. K.; Jayasankar, P.

2008-03-01

The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits.

A fossil unicorn crestfish (Teleostei, Lampridiformes, Lophotidae) from the Eocene of Iran

PubMed Central

2017-01-01

Lophotidae, or crestfishes, is a family of rare deep-sea teleosts characterised by an enlarged horn-like crest on the forehead. They are poorly represented in the fossil record, by only three described taxa. One specimen attributed to Lophotidae has been described from the pelagic fauna of the middle-late Eocene Zagros Basin, Iran. Originally considered as a specimen of the fossil lophotid †Protolophotus, it is proposed hereby as a new genus and species †Babelichthys olneyi, gen. et sp. nov., differs from the other fossil lophotids by its relatively long and strongly projecting crest, suggesting a close relationship with the modern unicorn crestfish, Eumecichthys. This new taxon increases the diversity of the deep-sea teleost fauna to which it belongs, improving our understanding of the taxonomic composition of the early Cenozoic mesopelagic ecosystems. PMID:28674642

Molecular analysis of ependymins from the cerebrospinal fluid of the orders Clupeiformes and Salmoniformes: no indication for the existence of an euteleost infradivision.

PubMed

Müller-Schmid, A; Ganss, B; Gorr, T; Hoffmann, W

1993-06-01

Ependymins represent the predominant protein constituents in the cerebrospinal fluid of many teleost fish and they are synthesized in meningeal fibroblasts. Here, we present the ependymin sequences from the herring (Clupea harengus) and the pike (Esox lucius). A comparison of ependymin homologous sequences from three different orders of teleost fish (Salmoniformes, Cypriniformes, and Clupeiformes) revealed the highest similarity between Clupeiformes and Cypriniformes. This result is unexpected because it does not reflect current systematics, in which Clupeiformes belong to a separate infradivision (Clupeomorpha) than Salmoniformes and Cypriniformes (Euteleostei). Furthermore, in Salmoniformes the evolutionary rate of ependymins seems to be accelerated mainly on the protein level. However, considering these inconstant rates, neither neighbor-joining trees nor DNA parsimony methods gave any indication that a separate euteleost infradivision exists.

A highly conserved N-terminal sequence for teleost vitellogenin with potential value to the biochemistry, molecular biology and pathology of vitellogenesis

USGS Publications Warehouse

Folmar, L.D.; Denslow, N.D.; Wallace, R.A.; LaFleur, G.; Gross, T.S.; Bonomelli, S.; Sullivan, C.V.

1995-01-01

N-terminal amino acid sequences for vitellogenin (Vtg) from six species of teleost fish (striped bass, mummichog, pinfish, brown bullhead, medaka, yellow perch and the sturgeon) are compared with published N-terminal Vtg sequences for the lamprey, clawed frog and domestic chicken. Striped bass and mummichog had 100% identical amino acids between positions 7 and 21, while pinfish, brown bullhead, sturgeon, lamprey, Xenopus and chicken had 87%, 93%, 60%, 47%, 47-60%) for four transcripts and had 40% identical, respectively, with striped bass for the same positions. Partial sequences obtained for medaka and yellow perch were 100% identical between positions 5 to 10. The potential utility of this conserved sequence for studies on the biochemistry, molecular biology and pathology of vitellogenesis is discussed.

Alterations in the activities of three dehydrogenases in the digestive system of two teleost fishes exposed to mercuric chloride

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

Gupta, P.K.; Sastry, K.V.

1981-02-01

The effect of the 50% lethal concentration and of a sublethal concentration (0.3 mg/liter) of mercuric chloride on the activities of succinic, lactic, and pyruvic dehydrogenases in the digestive system of two teleost fishes, Ophiocephalus punctatus and Heteropneustes fossilis, respectively, has been studied at intervals of 96 h and 7, 15, and 30 days. The results show that dehydrogenases are not affected much by short-term exposure. However, the activities of all three enzymes are inhibited by chronic exposure to mercury and maximum inhibition is observed after 15 days of exposure. Among the different parts of the digestive system, the livermore » is the most affected organ, and of the two fishes, Heteropneustes is more sensitive to mercury treatment.« less

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.

Defensive responses of cuttlefish to different teleost predators.

PubMed

Staudinger, Michelle D; Buresch, Kendra C; Mäthger, Lydia M; Fry, Charlie; McAnulty, Sarah; Ulmer, Kimberly M; Hanlon, Roger T

2013-12-01

We evaluated cuttlefish (Sepia officinalis) responses to three teleost predators: bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus), and black seabass (Centropristis striata). We hypothesized that the distinct body shapes, swimming behaviors, and predation tactics exhibited by the three fishes would elicit markedly different antipredator responses by cuttlefish. Over the course of 25 predator-prey behavioral trials, 3 primary and 15 secondary defense behaviors of cuttlefish were shown to predators. In contrast, secondary defenses were not shown during control trials in which predators were absent. With seabass-a benthic, sit-and-pursue predator-cuttlefish used flight and spent more time swimming in the water column than with other predators. With bluefish-an active, pelagic searching predator-cuttlefish remained closely associated with the substrate and relied more on cryptic behaviors. Startle (deimatic) displays were the most frequent secondary defense shown to seabass and bluefish, particularly the Dark eye ring and Deimatic spot displays. We were unable to evaluate secondary defenses by cuttlefish to flounder-a lie-and-wait predator-because flounder did not pursue cuttlefish or make attacks. Nonetheless, cuttlefish used primary defense during flounder trials, alternating between cryptic still and moving behaviors. Overall, our results suggest that cuttlefish may vary their behavior in the presence of different teleost predators: cryptic behaviors may be more important in the presence of active searching predators (e.g., bluefish), while conspicuous movements such as swimming in the water column and startle displays may be more prevalent with relatively sedentary, bottom-associated predators (e.g., seabass).

Elevated carbon dioxide alters the plasma composition and behaviour of a shark

PubMed Central

Green, Leon; Jutfelt, Fredrik

2014-01-01

Increased carbon emissions from fossil fuels are increasing the pCO2 of the ocean surface waters in a process called ocean acidification. Elevated water pCO2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks (Scyliorhinus canicula) to either control conditions or a year 2100 scenario of 990 μatm pCO2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated pCO2 group buffered internal acidosis via accumulation with an associated increase in Na+, indicating that the blood chemistry remained altered despite the long acclimation period. The elevated pCO2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO2-exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO2-exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO2, as in some teleosts, or that the sharks detect CO2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks. PMID:25232027

Evolutionary constraint on Otx2 neuroectoderm enhancers-deep conservation from skate to mouse and unique divergence in teleost

PubMed Central

Kurokawa, Daisuke; Sakurai, Yusuke; Inoue, Ai; Nakayama, Rika; Takasaki, Nobuyoshi; Suda, Yoko; Miyake, Tsutomu; Amemiya, Chris T.; Aizawa, Shinichi

2006-01-01

Otx2 is a paired type homeobox gene that plays essential roles in each step and site of head development in vertebrates. In the mouse, Otx2 expression in the anterior neuroectoderm is regulated primarily by two distinct enhancers: anterior neuroectoderm (AN) and forebrain/midbrain (FM) enhancers at 92 kb and 75 kb 5′of the Otx2 locus, respectively. The AN enhancer has activity in the entire anterior neuroectoderm at headfold and early somite stages, whereas the FM enhancer is subsequently active in the future caudal forebrain and midbrain ectoderm. In tetrapods, both AN and FM enhancers are conserved, whereas the AN region is missing in teleosts, despite overt Otx2 expression in the anterior neuroectoderm. Here, we show that zebrafish and fugu FM regions drive expression not only in the forebrain and midbrain but also in the anterior neuroectoderm at headfold stage. The analysis of coelacanth and skate genomic Otx2 orthologues suggests that the utilization of the two enhancers, AN and FM, is an ancestral condition. In contrast, the AN enhancer has been specifically lost in the teleost lineage with a compensatory establishment of AN activity within the FM enhancer. Furthermore, the AN activity in the fish FM enhancer was established by recruiting upstream factors different from those that direct the tetrapod AN enhancer, yet zebrafish FM enhancer is active in both mouse and zebrafish anterior neuroectoderm at the headfold stage. PMID:17159156

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens

USGS Publications Warehouse

Iwanowicz, Luke R.; Stafford, James L.; Patiño, Reynaldo; Bengten, Eva; Miller, Norman W.; Blazer, Vicki

2014-01-01

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish (Ictalurus punctaus) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro. Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines.

Genomic regulatory blocks encompass multiple neighboring genes and maintain conserved synteny in vertebrates

PubMed Central

Kikuta, Hiroshi; Laplante, Mary; Navratilova, Pavla; Komisarczuk, Anna Z.; Engström, Pär G.; Fredman, David; Akalin, Altuna; Caccamo, Mario; Sealy, Ian; Howe, Kerstin; Ghislain, Julien; Pezeron, Guillaume; Mourrain, Philippe; Ellingsen, Staale; Oates, Andrew C.; Thisse, Christine; Thisse, Bernard; Foucher, Isabelle; Adolf, Birgit; Geling, Andrea; Lenhard, Boris; Becker, Thomas S.

2007-01-01

We report evidence for a mechanism for the maintenance of long-range conserved synteny across vertebrate genomes. We found the largest mammal-teleost conserved chromosomal segments to be spanned by highly conserved noncoding elements (HCNEs), their developmental regulatory target genes, and phylogenetically and functionally unrelated “bystander” genes. Bystander genes are not specifically under the control of the regulatory elements that drive the target genes and are expressed in patterns that are different from those of the target genes. Reporter insertions distal to zebrafish developmental regulatory genes pax6.1/2, rx3, id1, and fgf8 and miRNA genes mirn9-1 and mirn9-5 recapitulate the expression patterns of these genes even if located inside or beyond bystander genes, suggesting that the regulatory domain of a developmental regulatory gene can extend into and beyond adjacent transcriptional units. We termed these chromosomal segments genomic regulatory blocks (GRBs). After whole genome duplication in teleosts, GRBs, including HCNEs and target genes, were often maintained in both copies, while bystander genes were typically lost from one GRB, strongly suggesting that evolutionary pressure acts to keep the single-copy GRBs of higher vertebrates intact. We show that loss of bystander genes and other mutational events suffered by duplicated GRBs in teleost genomes permits target gene identification and HCNE/target gene assignment. These findings explain the absence of evolutionary breakpoints from large vertebrate chromosomal segments and will aid in the recognition of position effect mutations within human GRBs. PMID:17387144

CsMAP34, a teleost MAP with dual role: A promoter of MASP-assisted complement activation and a regulator of immune cell activity.

PubMed

Li, Mo-Fei; Li, Jun; Sun, Li

2016-12-23

In teleost fish, the immune functions of mannan-binding lectin (MBL) associated protein (MAP) and MBL associated serine protease (MASP) are scarcely investigated. In the present study, we examined the biological properties both MAP (CsMAP34) and MASP (CsMASP1) molecules from tongue sole (Cynoglossus semilaevis). We found that CsMAP34 and CsMASP1 expressions occurred in nine different tissues and were upregulated by bacterial challenge. CsMAP34 protein was detected in blood, especially during bacterial infection. Recombinant CsMAP34 (rCsMAP34) bound C. semilaevis MBL (rCsBML) when the latter was activated by bacteria, while recombinant CsMASP1 (rCsMASP1) bound activated rCsBML only in the presence of rCsMAP34. rCsMAP34 stimulated the hemolytic and bactericidal activities of serum complement, whereas anti-CsMAP34 antibody blocked complement activities. Knockdown of CsMASP1 in C. semilaevis resulted in significant inhibition of complement activities. Furthermore, rCsMAP34 interacted directly with peripheral blood leukocytes (PBL) and enhanced the respiratory burst, acid phosphatase activity, chemotactic activity, and gene expression of PBL. These results indicate for the first time that a teleost MAP acts one hand as a regulator that promotes the lectin pathway of complement activation via its ability to recruit MBL to MASP, and other hand as a modulator of immune cell activity.

Spatially-Explicit Holocene Drought Reconstructions in Amazonian Forests

NASA Astrophysics Data System (ADS)

McMichael, C.; Bush, M. B.

2014-12-01

Climate models predict increasing drought in Amazonian forests over the next century, and the synergy of drought and fire may lead to forest dieback. El Niño Southern Oscillation (ENSO) and the Atlantic Multi-decadal Oscillation (AMO) are two primary drivers of Amazonian drought, and each process has a spatially distinct manifestation in the Basin. Paleoecological reconstructions can contextualize the forest response to past drought periods. Stalagmite and lake sediment records have documented that the early- to mid-Holocene, i.e. 10,000 - 5000 calibrated years before present (cal yr BP), was among the driest periods of the last 100,000 years in western Amazonia. Climatic conditions became wetter and more similar to the modern climate over the last 4000 cal yr BP, and fires rarely occurred in the absence of human activity. Yet there are currently no drought and fire reconstructions that examine the spatially explicit patterns of drought during the Holocene. Here, we present regional drought histories from southwestern and northeastern sections Amazonia for the last 10,000 years that document the drought-fire dynamics resulting from both climatic processes. Our reconstructions were based on a compilation of dated soil charcoal fragments (N= 291) collected from within Amazonia sensu stricto, which were analyzed by region using summed probability analysis. The compiled soil charcoal dates contained limited evidence of fire over the last 10,000 years in some regions. Fire frequency rose markedly across the Basin, however, during the last 2000 years, indicating an increased human presence. Fire probabilities, and thus droughts, had similar increasing trajectories between southwestern and northeastern Amazonia from 1500-1100 cal yr BP, which decoupled from 1100-740 cal yr BP, and then regained synchronicity from 740-500 cal yr BP. Fire probability declined markedly after 500 yr cal BP, coincident with European arrival to the Americas. Native populations were decimated, and fire probabilities returned to similar levels before the rise 2000 years ago. These results suggested that the synergy of humans plus drought have played a large role in historical fire regimes in Amazonian forests for the last 2000 years.

Urban and architectural risk factors for malaria in indigenous Amazonian settlements in Brazil: a typological analysis.

PubMed

Leandro-Reguillo, Patricia; Thomson-Luque, Richard; Monteiro, Wuelton M; de Lacerda, Marcus V G

2015-07-22

In the Amazon, m alaria is highly endemic in indigenous populations, which are often considered one of the last barriers to malaria elimination due to geographic isolation. Although the improvement of housing conditions is a good strategy towards the control and prevention of vector-borne diseases, such as malaria, this preventive practice has been barely undertaken in Latin America. An analysis of the architectural and urban features of indigenous Amazonian populations is essential to define and adapt these vector control measures. A total of 32 villages of 29 different ethnicities were studied and mapped by reviewing literature and visual information, and using a geographic information system. The most important architectural and urban characteristics influencing malaria were analysed according to the following categories: number of households and dimensions, supporting area, openings, materials, lifespan and location. Housing typologies found were classified within each of these variables. The results of this typological analysis included an easy-to-handle working template and revealing of features that benefit or hamper the presence of malaria vectors in Amerindians communities. Among risk factors, presence of open eaves, permeable walls, open-side constructions, large number of sleepers indoors, temporary-ephemeral houses, linear villages along stream banks, houseboats villages, poor urban drainage and villages surrounded by anthropogenic environments were highlighted. Indigenous settlements very permissive for anophelines were identified in ethnic groups, such as the Yanomami, Palikur, Paumari, Waimiri-Atroari and Wajãpi. Positive features were also recognized, including opaque and closed houses, large radial villages on bare soil, highly elevated stilted houses and the fire indoors, found among the Yawalapiti, Ashaninka, and Gavião-Parkatejê tribes. However, as Amazonian indigenous settlement typologies vary greatly even among villages of the same ethnic group, it is imperative to undertake an individual study for each community. Using the working template in Amazonian settlements it is possible to obtain data that will help researchers not only understand how architectural and urban features affect transmission, but also define vector control measures easily applicable by health authorities and acceptable by these communities.

Understanding the Sensitivity of a GCM Simulation of Amazonian Deforestation to the Specification of Vegetation and Soil Characteristics.

NASA Astrophysics Data System (ADS)

Lean, J.; Rowntree, P. R.

1997-06-01

The experiment reported on here presents a realistic portrayal of Amazonian deforestation that uses measurements of vegetation characteristics, taken as part of the Anglo-Brazilian Amazonian Climate Observation Study field campaigns, to define the forest and replacement pasture vegetation in the Hadley Centre GCM. The duration of the main experiment (10 yr) leads to greater confidence in assessing regional changes than in previous shorter experiments.Complete removal of the Amazonian forest produced area-mean changes that resemble earlier experiments with decreases in evaporation of 0.76 mm day1 (18%) and rainfall of 0.27 mm day1 (4%) and a rise in surface temperature of 2.3°C. However, the relative changes in magnitude indicate that increased moisture convergence partly compensates for the reduced evaporation, in contrast to many previous deforestation experiments. Results also showed large regional variations in the change in annual mean rainfall over South America, with widespread decreases over most of the deforested area and increases near the Andes.A better understanding of the mechanisms responsible for the final deforested climate has been gained by carrying out additional experiments that examine the response to separate changes in roughness and albedo. Increased albedo resulted in widespread significant decreases in rainfall due to less moisture convergence and ascent. The response to reduced roughness is more complex but of comparable importance; in this experiment it was dominated by an increase in low-level wind speeds resulting in decreased moisture convergence and rainfall near the upwind edge of the area and the opposite near the downwind boundary where the increased flow meets the Andes.In the standard deforestation scenario all vegetation parameters were modified together with one soil parameter-the maximum infiltration rate, which is reduced to represent the observed compaction of soil following deforestation. Results from a further experiment, in which the maximum infiltration rate was left unchanged, showed much smaller reductions in evaporation of 0.3 mm day1 (7%) and indicated that the predicted regional changes in rainfall and evaporation were very sensitive to this parameter.

Studying the Effects of Amazonian Land Cover Change on Glacier Mass Balance in the Tropical Andes

NASA Astrophysics Data System (ADS)

Mark, B. G.; Fernandez, A.; Gabrielli, P.; Montenegro, A.; Postigo, J.; Hellstrom, R. A.

2017-12-01

Recent research has highlighted several ongoing environmental changes occurring across Tropical South America, including Andean glacier retreat, drought, as well as changes in land-use and land-cover. As the regional climate of the area is mostly characterized by land-ocean interactions, the atmospheric convection in the Amazon, and the effect of the Andes on circulation patterns, it follows that changes in one of those regions may affect the other. Most scholars who have studied the causes of tropical glaciers' fluctuations have not analyzed the linkages with changes in the Amazon with the same attention paid to the influence of Pacific sea surface temperature. Here we study the response of glacier surface mass balance in the Cordillera Blanca, Peru (10°S), to a scenario where the Amazonian rainforest is replaced by savannas. We ran climatic simulations at 2-km spatial resolution utilizing the Weather Research and Forecasting (WRF) model considering two scenarios: (a) control (CRTL), with today's rainforest extent; and (b) land cover change (LCC), where all the rainforest was replaced by savanna. WRF output was in turn ingested into a glacier energy and mass balance (GEMB) model that we validate by reconstructing both the accumulated mass balance from available observations, and the altitudinal distribution of mass balance in the region. Seasonal comparison between CRTL and LCC scenarios indicates that forest replacement by savanna results in more positive glacier mass balance. This shift to more positive mass balance contrasts with a (WRF) modeled rise in the elevation of the freezing line (0°C) between 30 to 120 m for the LCC scenario. Our results are surprising because most previous studies have shown that reducing Amazon forest cover diminishes rainfall and increases temperature, suggesting that glaciers should lose mass. We hypothesize and discuss implications of possible land-atmospheric processes that might drive this tropical glacier response to Amazonian forest change, including: the large-scale influence of Amazonian albedo change on the interaction between the Walker and Hadley cells and the effect of mountain meteorology dynamics.

Geological control of floristic composition in Amazonian forests

PubMed Central

Higgins, Mark A; Ruokolainen, Kalle; Tuomisto, Hanna; Llerena, Nelly; Cardenas, Glenda; Phillips, Oliver L; Vásquez, Rodolfo; Räsänen, Matti

2011-01-01

Aim Conservation and land-use planning require accurate maps of patterns in species composition and an understanding of the factors that control them. Substantial doubt exists, however, about the existence and determinants of large-area floristic divisions in Amazonia. Here we ask whether Amazonian forests are partitioned into broad-scale floristic units on the basis of geological formations and their edaphic properties. Location Western and central Amazonia. Methods We used Landsat imagery and Shuttle Radar Topography Mission (SRTM) digital elevation data to identify a possible floristic and geological discontinuity of over 300 km in northern Peru. We then used plant inventories and soil sampling to document changes in species composition and soil properties across this boundary. Data were obtained from 138 sites distributed along more than 450 km of road and river. On the basis of our findings, we used broad-scale Landsat and SRTM mosaics to identify similar patterns across western and central Amazonia. Results The discontinuity identified in Landsat and SRTM data corresponded to a 15-fold change in soil cation concentrations and an almost total change in plant species composition. This discontinuity appears to be caused by the widespread removal of cation-poor surface sediments by river incision to expose cation-rich sediments beneath. Examination of broad-scale Landsat and SRTM mosaics indicated that equivalent processes have generated a north–south discontinuity of over 1500 km in western Brazil. Due to similarities with our study area, we suggest that this discontinuity represents a chemical and ecological limit between western and central Amazonia. Main conclusions Our findings suggest that Amazonian forests are partitioned into large-area units on the basis of geological formations and their edaphic properties. The evolution of these units through geological time may provide a general mechanism for biotic diversification in Amazonia. These compositional units, moreover, may correspond to broad-scale functional units. The existence of large-area compositional and functional units would suggest that protected-area, carbon sequestration, and other land-use strategies in Amazonia be implemented on a region-by-region basis. The methods described here can be used to map these patterns, and thus enable effective conservation and management of Amazonian forests. PMID:22247585

Math skills and market and non-market outcomes: Evidence from an Amazonian society of forager-farmers.

PubMed

Undurraga, Eduardo A; Behrman, Jere R; Grigorenko, Elena L; Schultz, Alan; Yiu, Julie; Godoy, Ricardo A

2013-12-01

Research in industrial nations suggests that formal math skills are associated with improvements in market and non-market outcomes. But do these associations also hold in a highly autarkic setting with a limited formal labor market? We examined this question using observational annual panel data (2008 and 2009) from 1,121 adults in a native Amazonian society of forager-farmers in Bolivia (Tsimane'). Formal math skills were associated with an increase in wealth in durable market goods and in total wealth between data collection rounds, and with improved indicators of own reported perceived stress and child health. These associations did not vary significantly by people's Spanish skills or proximity to town. We conclude that the positive association between math skills and market and non-market outcomes extends beyond industrial nations to even highly autarkic settings.

Pervasive Rise of Small-scale Deforestation in Amazonia.

PubMed

Kalamandeen, Michelle; Gloor, Emanuel; Mitchard, Edward; Quincey, Duncan; Ziv, Guy; Spracklen, Dominick; Spracklen, Benedict; Adami, Marcos; Aragão, Luiz E O C; Galbraith, David

2018-01-25

Understanding forest loss patterns in Amazonia, the Earth's largest rainforest region, is critical for effective forest conservation and management. Following the most detailed analysis to date, spanning the entire Amazon and extending over a 14-year period (2001-2014), we reveal significant shifts in deforestation dynamics of Amazonian forests. Firstly, hotspots of Amazonian forest loss are moving away from the southern Brazilian Amazon to Peru and Bolivia. Secondly, while the number of new large forest clearings (>50 ha) has declined significantly over time (46%), the number of new small clearings (<1 ha) increased by 34% between 2001-2007 and 2008-2014. Thirdly, we find that small-scale low-density forest loss expanded markedly in geographical extent during 2008-2014. This shift presents an important and alarming new challenge for forest conservation, despite reductions in overall deforestation rates.

Glacial geology of the Hellas region on Mars

NASA Technical Reports Server (NTRS)

Kargel, Jeffrey S.; Strom, Robert G.; Johnson, Natasha

1991-01-01

A glacial geologic interpretation was recently presented for Argyre, which is herein extended to Hellas. This glacial event is believed to constitute an important link in a global cryohydric epoch of Middle Amazonian age. At glacial maximum, ice apparently extended far beyond the regions of Argyre and Hellas, and formed what is termed as the Austral Ice Sheet, an agglomeration of several ice domes and lobes including the Hellas Lobe. It is concluded that Hellas was apparently heavily glaciated. Also glaciation was young by Martian standards (Middle Amazonian), and ancient by terrestrial standards. Glaciation appears to have occurred during the same period that other areas on Mars were experiencing glaciation and periglacial activity. Glaciation seems to have occurred as a geological brief epoch of intense geomorphic activity in an era characterized by long periods of relative inactivity.

Elemental mercury in the atmosphere of a tropical Amazonian forest (French Guiana)

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

Amouroux, D.; Wasserman, J.C.Tessier, E.; Donard, O.F.X.

1999-09-01

Gaseous atmospheric mercury was investigated at two sites of a tropical Amazonian forest (French Guiana) in the Petit Inini River basin and the Petit Saut Lake in June, 1998. Gaseous atmospheric mercury was identified as elemental mercury (Hg{sup 0}). Diurnal variation of atmospheric Hg{sup 0} in both studied aquatic environments were significantly correlated with air temperature and anticorrelated with relative humidity. Average Hg{sup 0} concentrations were higher above the Petit Inini River that the Petit Saut Lake. Background Hg{sup 0} concentrations in the Petit Inini River basin were higher than those observed in remote environments. These data suggest that goldmore » mining activity (i.e., Petit Inini River basin) may influence mercury mobilization in tropical forest ecosystems and that atmospheric transfer is a major pathway for mercury cycling in these environments.« less

Impact of pre-Columbian “geoglyph” builders on Amazonian forests

PubMed Central

Watling, Jennifer; Iriarte, José; Schaan, Denise; Pessenda, Luiz C. R.; Loader, Neil J.; Dickau, Ruth E.; Damasceno, Antonia; Ranzi, Alceu

2017-01-01

Over 450 pre-Columbian (pre-AD 1492) geometric ditched enclosures (“geoglyphs”) occupy ∼13,000 km2 of Acre state, Brazil, representing a key discovery of Amazonian archaeology. These huge earthworks were concealed for centuries under terra firme (upland interfluvial) rainforest, directly challenging the “pristine” status of this ecosystem and its perceived vulnerability to human impacts. We reconstruct the environmental context of geoglyph construction and the nature, extent, and legacy of associated human impacts. We show that bamboo forest dominated the region for ≥6,000 y and that only small, temporary clearings were made to build the geoglyphs; however, construction occurred within anthropogenic forest that had been actively managed for millennia. In the absence of widespread deforestation, exploitation of forest products shaped a largely forested landscape that survived intact until the late 20th century. PMID:28167791

Impact of pre-Columbian "geoglyph" builders on Amazonian forests.

PubMed

Watling, Jennifer; Iriarte, José; Mayle, Francis E; Schaan, Denise; Pessenda, Luiz C R; Loader, Neil J; Street-Perrott, F Alayne; Dickau, Ruth E; Damasceno, Antonia; Ranzi, Alceu

2017-02-21

Over 450 pre-Columbian (pre-AD 1492) geometric ditched enclosures ("geoglyphs") occupy ∼13,000 km 2 of Acre state, Brazil, representing a key discovery of Amazonian archaeology. These huge earthworks were concealed for centuries under terra firme (upland interfluvial) rainforest, directly challenging the "pristine" status of this ecosystem and its perceived vulnerability to human impacts. We reconstruct the environmental context of geoglyph construction and the nature, extent, and legacy of associated human impacts. We show that bamboo forest dominated the region for ≥6,000 y and that only small, temporary clearings were made to build the geoglyphs; however, construction occurred within anthropogenic forest that had been actively managed for millennia. In the absence of widespread deforestation, exploitation of forest products shaped a largely forested landscape that survived intact until the late 20th century.

Individual differences in cognition among teleost fishes.

PubMed

Lucon-Xiccato, Tyrone; Bisazza, Angelo

2017-08-01

Individual differences in cognitive abilities have been thoroughly investigated in humans and to a lesser extent in other mammals. Despite the growing interest in studying cognition in other taxonomic groups, data on individual differences are scarce for non-mammalian species. Here, we review the literature on individual differences in cognitive abilities in teleost fishes. Relatively few studies have directly addressed this topic and have provided evidence of consistent and heritable individual variation in cognitive abilities in fish. We found much more evidence of individual cognitive differences in other research areas, namely sex differences, personality differences, cerebral lateralisation and comparison between populations. Altogether, these studies suggest that individual differences in cognition are as common in fish as in warm-blooded vertebrates. Based on the example of research on mammals, we suggest directions for future investigation in fish. Copyright © 2017 Elsevier B.V. All rights reserved.

Fish T cells: recent advances through genomics

USGS Publications Warehouse

Laing, Kerry J.; Hansen, John D.

2011-01-01

This brief review is intended to provide a concise overview of the current literature concerning T cells, advances in identifying distinct T cell functional subsets, and in distinguishing effector cells from memory cells. We compare and contrast a wealth of recent progress made in T cell immunology of teleost, elasmobranch, and agnathan fish, to knowledge derived from mammalian T cell studies. From genome studies, fish clearly have most components associated with T cell function and we can speculate on the presence of putative T cell subsets, and the ability to detect their differentiation to form memory cells. Some recombinant proteins for T cell associated cytokines and antibodies for T cell surface receptors have been generated that will facilitate studying the functional roles of teleost T cells during immune responses. Although there is still a long way to go, major advances have occurred in recent years for investigating T cell responses, thus phenotypic and functional characterization is on the near horizon.

Assessment of different protocols for the isolation and purification of gut associated lymphoid cells from the gilthead seabream (Sparus aurata L.)

PubMed Central

2007-01-01

Teleost gut associated lymphoid tissue (GALT) consists of leucocyte populations located both intraepithelially and in the lamina propria with no structural organization. The present study aims to assess different protocols for the isolation of GALT cells from an important fish species in the Mediterranean aquaculture, the gilthead seabream. Mechanical, chemical and enzymatic treatments were assayed. Nylon wool columns and continuous density gradients were used for further separation of cell subpopulations. Light microscopy and flow cytometry showed that the highest density band (HD) consisted of a homogeneous lymphocytic population, whereas the intermediate density band (ID) corresponded to epithelial and secretory cells and some lymphocytes. Respiratory burst activity of total cell suspensions revealed very low numbers of potential phagocytic cells, reflecting results from light microscopy and reports in other teleost species. The present data set up the basis for future functional characterization of GALT in seabream. PMID:18213363

Diversity of trypanorhynch metacestodes in teleost fishes from coral reefs off eastern Australia and New Caledonia

PubMed Central

Beveridge, Ian; Bray, Rodney A.; Cribb, Thomas H.; Justine, Jean-Lou

2014-01-01

Trypanorhynch metacestodes were examined from teleosts from coral reefs in eastern Australia and from New Caledonia. From over 12,000 fishes examined, 33 named species of trypanorhynchs were recovered as well as three species of tentacularioids which are described but not named. Host-parasite and parasite-host lists are provided, including more than 100 new host records. Lacistorhynchoid and tentacularioid taxa predominated with fewer otobothrioid and gymnorhynchoids. Five species, Callitetrarhynchus gracilis, Floriceps minacanthus, Pseudotobothrium dipsacum, Pseudolacistorhynchus heroniensis and Ps. shipleyi, were particularly common and exhibited low host specificity. Limited data suggested a higher diversity of larval trypanorhynchs in larger piscivorous fish families. Several fish families surveyed extensively (Blenniidae, Chaetodontidae, Gobiidae, Kyphosidae and Scaridae) yielded no trypanorhynch larvae. The overall similarity between the fauna of the Great Barrier Reef and New Caledonia was 45%. Where available, information on the adult stages in elasmobranchs has been included. PMID:25402635

A Role for Oxytocin-Like Receptor in Social Habituation in a Teleost.

PubMed

Weitekamp, Chelsea A; Solomon-Lane, Tessa K; Del Valle, Pamela; Triki, Zegni; Nugent, Bridget M; Hofmann, Hans A

2017-01-01

Oxytocin (OT) mediates social habituation in rodent model systems, but its role in mediating this effect in other vertebrates is unknown. We used males of the African cichlid fish, Astatotilapia burtoni, to investigate two aspects of isotocin (IT; an OT homolog) signaling in social habituation. First, we examined the expression of IT receptor 2 (ITR2) as well as two immediate early genes in brain regions implicated in social recognition. Next, we examined IT neuron activity using immunohistochemistry. Patterns of gene expression in homologs of the amygdala and hippocampus implicate IT signaling in these regions in social habituation to a territorial neighbor. In the preoptic area, the expression of the ITR2 subtype and IT neuron activity respond to the presence of a male, independent of familiarity. Our results implicate IT in mediating social habituation in a teleost. © 2017 S. Karger AG, Basel.

Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock

PubMed Central

Lleras Forero, Laura; Narayanan, Rachna; Huitema, Leonie FA; VanBergen, Maaike; Apschner, Alexander; Peterson-Maduro, Josi; Logister, Ive; Valentin, Guillaume

2018-01-01

Segmentation of the axial skeleton in amniotes depends on the segmentation clock, which patterns the paraxial mesoderm and the sclerotome. While the segmentation clock clearly operates in teleosts, the role of the sclerotome in establishing the axial skeleton is unclear. We severely disrupt zebrafish paraxial segmentation, yet observe a largely normal segmentation process of the chordacentra. We demonstrate that axial entpd5+ notochord sheath cells are responsible for chordacentrum mineralization, and serve as a marker for axial segmentation. While autonomous within the notochord sheath, entpd5 expression and centrum formation show some plasticity and can respond to myotome pattern. These observations reveal for the first time the dynamics of notochord segmentation in a teleost, and are consistent with an autonomous patterning mechanism that is influenced, but not determined by adjacent paraxial mesoderm. This behavior is not consistent with a clock-type mechanism in the notochord. PMID:29624170

Normal development of the tomato clownfish Amphiprion frenatus: live imaging and in situ hybridization analyses of mesodermal and neurectodermal development.

PubMed

Ghosh, J; Wilson, R W; Kudoh, T

2009-12-01

The normal embryonic development of the tomato clownfish Amphiprion frenatus was analysed using live imaging and by in situ hybridization for detection of mesodermal and neurectodermal development. Both morphology of live embryos and tissue-specific staining revealed significant differences in the gross developmental programme of A. frenatus compared with better-known teleost fish models, in particular, initiation of somitogenesis before complete epiboly, initiation of narrowing of the neurectoderm (neurulation) before somitogenesis, relatively early pigmentation of melanophores at the 10-15 somite stage and a distinctive pattern of melanophore distribution. These results suggest evolutionary adaptability of the teleost developmental programme. The ease of obtaining eggs, in vitro culture of the embryo, in situ staining analyses and these reported characteristics make A. frenatus a potentially important model marine fish species for studying embryonic development, physiology, ecology and evolution.

The Genomic and Genetic Toolbox of the Teleost Medaka (Oryzias latipes)

PubMed Central

Kirchmaier, Stephan; Naruse, Kiyoshi; Wittbrodt, Joachim; Loosli, Felix

2015-01-01

The Japanese medaka, Oryzias latipes, is a vertebrate teleost model with a long history of genetic research. A number of unique features and established resources distinguish medaka from other vertebrate model systems. A large number of laboratory strains from different locations are available. Due to a high tolerance to inbreeding, many highly inbred strains have been established, thus providing a rich resource for genetic studies. Furthermore, closely related species native to different habitats in Southeast Asia permit comparative evolutionary studies. The transparency of embryos, larvae, and juveniles allows a detailed in vivo analysis of development. New tools to study diverse aspects of medaka biology are constantly being generated. Thus, medaka has become an important vertebrate model organism to study development, behavior, and physiology. In this review, we provide a comprehensive overview of established genetic and molecular-genetic tools that render medaka fish a full-fledged vertebrate system. PMID:25855651

Discovering Hidden Diversity of Characins (Teleostei: Characiformes) in Ecuador's Yasuní National Park.

PubMed

Escobar-Camacho, Daniel; Barriga, Ramiro; Ron, Santiago R

2015-01-01

Management and conservation of biodiversity requires adequate species inventories. The Yasuní National Park is one of the most diverse regions on Earth and recent studies of terrestrial vertebrates, based on genetic evidence, have shown high levels of cryptic and undescribed diversity. Few genetic studies have been carried out in freshwater fishes from western Amazonia. Thus, in contrast with terrestrial vertebrates, their content of cryptic diversity remains unknown. In this study, we carried out genetic and morphological analyses on characin fishes at Yasuní National Park, in eastern Ecuador. Our goal was to identify cryptic diversity among one of the most speciose fish families in the Amazon region. This is the first time that genetic evidence has been used to assess the species content of the Napo Basin, one of the richest regions in vertebrate diversity. Phylogenetic analyses of partial mitochondrial 16S ribosomal RNA gene (∼600 pb) DNA sequences from 232 specimens of the family Characidae and its closest groups revealed eight candidate new species among 33 species sampled, representing a 24% increase in species number. Analyses of external morphology allowed us to confirm the species status of six of the candidate species. Our results show high levels of cryptic diversity in Amazonian characins. If this group is representative of other Amazonian fish, our results would imply that the species richness of the Amazonian ichthyofauna is highly underestimated. Molecular methods are a necessary tool to obtain more realistic inventories of Neotropical freshwater fishes.

Unravelling the life history of Amazonian fishes through otolith microchemistry

PubMed Central

Hermann, Theodore W.; Stewart, Donald J.; Limburg, Karin E.; Castello, Leandro

2016-01-01

Amazonian fishes employ diverse migratory strategies, but the details of these behaviours remain poorly studied despite numerous environmental threats and heavy commercial exploitation of many species. Otolith microchemistry offers a practical, cost-effective means of studying fish life history in such a system. This study employed a multi-method, multi-elemental approach to elucidate the migrations of five Amazonian fishes: two ‘sedentary’ species (Arapaima sp. and Plagioscion squamosissimus), one ‘floodplain migrant’ (Prochilodus nigricans) and two long-distance migratory catfishes (Brachyplatystoma rousseauxii and B. filamentosum). The Sr : Ca and Zn : Ca patterns in Arapaima were consistent with its previously observed sedentary life history, whereas Sr : Ca and Mn : Ca indicated that Plagioscion may migrate among multiple, chemically distinct environments during different life-history stages. Mn : Ca was found to be potentially useful as a marker for identifying Prochilodus's transition from its nursery habitats into black water. Sr : Ca and Ba : Ca suggested that B. rousseauxii resided in the Amazon estuary for the first 1.5–2 years of life, shown by the simultaneous increase/decrease of otolith Sr : Ca/Ba : Ca, respectively. Our results further suggested that B. filamentosum did not enter the estuary during its life history. These results introduce what should be a productive line of research desperately needed to better understand the migrations of these unique and imperilled fishes. PMID:27429777

Recovery of Areas Degraded by Mining Within the Amazon Forest: Interaction of the Physical Condition of Soil and Biological Activity

NASA Astrophysics Data System (ADS)

Ribeiro, A. I.; Mello, G. F.; Longo, R. M.; Fengler, F. H.; Peche Filho, A., Sr.

2017-12-01

One of the greatest natural riches of Brazil is the Amazon rainforest. The Amazon region is known for its abundance of mineral resources, and may include topaz, oil, and especially cassiterite. In this scope, the mining sector in Brazil has great strategic importance because it accounts for approximately 30% of the country's exports with a mineral production of 40 billion dollars (Brazilian Mining Institute, 2015). In this scenario, as a consequence of mining, the Amazonian ecosystem has been undergoing a constant process of degradation. An important artifice in the exploitation of mineral resources is the rehabilitation and/or recovery of degraded areas. This recovery requires the establishment of degradation indicators and also the quality of the soil associated with its biota, since the Amazonian environment is dynamic, heterogeneous and complex in its physical, chemical and biological characteristics. In this way, this work presupposes that it is possible to characterize the different stages of recovery of tillage floor areas in deactivated cassiterite mines, within the Amazonian forest, in order to evaluate the interactions between the level of biological activity (Serrapilheira Height, Coefficient Metabolic, Basal Breath) and physical soil characteristics (aggregate DMG, Porosity, Total Soil Density, Moisture Content), through canonical correlation analysis. The results present correlations between the groups of indicators. Thus, from the use of the groups defined by canonical correlations, it was possible to identify the response of the set of physical and biological variables to the areas at different stages of recovery.

The revised tectonic history of Tharsis

NASA Astrophysics Data System (ADS)

Bouley, Sylvain; Baratoux, David; Paulien, Nicolas; Missenard, Yves; Saint-Bézar, Bertrand

2018-04-01

Constraining the timing of the emplacement of the volcano-tectonic province of Tharsis is critical to understanding the evolution of mantle, surface environment and climate of Mars. The growth of Tharsis had exerted stresses on the lithosphere, which were responsible for tectonic deformation, previously mapped as radial or concentric faults. Insights into the emplacement history of Tharsis may be gained from an analysis of the characteristics and ages of these tectonic features. The number, total length, linear density of extensional or compressional faults in the Tharsis region and deformation rates are reported for each of the following 6 stages: Early and Middle Noachian (stage 1); Late Noachian (stage 2); Early Hesperian (stage 3); Late Hesperian (stage 4), Early Amazonian (stage 5) and Middle Amazonian to Late Amazonian (stage 6). 8571 Tharsis-related tectonic features (radial or concentric to the center of Tharsis) were assigned to one of these periods of time based on their relationship with stratigraphic units defined in the most recent geological map. Intense faulting at Tempe Terra, Claritas and Coracis Fossae and Thaumasia Planum confirms that tectonic deformation started during the Noachian. However, we report a peak in both compressive and extensive rates of deformation during the Early Hesperian whereas the quantitative indicators for compressional and extensional tectonics vary within less than one order of magnitude from the Late Noachian to the Late Hesperian. These observations indicate a protracted growth of Tharsis during the first quarter of Mars evolution and declining from 3 Gyrs ago.

Reassessment of asymptomatic carriers of Plasmodium spp. in an endemic area with a very low incidence of malaria in extra-Amazonian Brazil.

PubMed

de Alencar, Filomena E C; Malafronte, Rosely Dos Santos; Cerutti, Crispim; Natal Fernandes, Lícia; Buery, Julyana Cerqueira; Fux, Blima; Rezende, Helder Ricas; Miranda, Angelica Espinosa

2017-11-09

Regions with residual transmission are potential obstacles to the elimination of malaria. It is, therefore, essential to understand the factors associated with the maintenance of endemic malaria in these areas. The objective was to investigate whether the status of asymptomatic carriers of Plasmodium spp. DNA is maintained in the long term in an extra-Amazonian region of Brazil with low incidence, residual malaria transmission. Asymptomatic carriers of Plasmodium DNA detected in a survey carried out between 2001 and 2004 were reassessed between 2010 and 2011 using questionnaires, PCR and thick and thin blood smear tests three times at 3-month intervals. Of the 48 carriers detected between 2001 and 2004, 37 were located. Of these, only two had positive PCR results and, as in the first survey, Plasmodium malariae DNA was detected. The findings suggest that untreated dwellers from this extra-Amazonian region, who initially harbour malaria parasites, may become negative without ever developing apparent symptoms of the disease. Although the possibility of re-infection cannot be ruled out, the finding of two individuals harbouring P. malariae, both in the first and in the second survey, may be compatible with a long-term carrier state for this parasite. Since most clinical cases of malaria in the region are a consequence of infection by Plasmodium vivax, the epidemiological impact of such long-term carriage would be limited.

Distribution of androgen receptor mRNA expression in vocal, auditory, and neuroendocrine circuits in a teleost fish.

PubMed

Forlano, Paul M; Marchaterre, Margaret; Deitcher, David L; Bass, Andrew H

2010-02-15

Across all major vertebrate groups, androgen receptors (ARs) have been identified in neural circuits that shape reproductive-related behaviors, including vocalization. The vocal control network of teleost fishes presents an archetypal example of how a vertebrate nervous system produces social, context-dependent sounds. We cloned a partial cDNA of AR that was used to generate specific probes to localize AR expression throughout the central nervous system of the vocal plainfin midshipman fish (Porichthys notatus). In the forebrain, AR mRNA is abundant in proposed homologs of the mammalian striatum and amygdala, and in anterior and posterior parvocellular and magnocellular nuclei of the preoptic area, nucleus preglomerulosus, and posterior, ventral and anterior tuberal nuclei of the hypothalamus. Many of these nuclei are part of the known vocal and auditory circuitry in midshipman. The midbrain periaqueductal gray, an essential link between forebrain and hindbrain vocal circuitry, and the lateral line recipient nucleus medialis in the rostral hindbrain also express abundant AR mRNA. In the caudal hindbrain-spinal vocal circuit, high AR mRNA is found in the vocal prepacemaker nucleus and along the dorsal periphery of the vocal motor nucleus congruent with the known pattern of expression of aromatase-containing glial cells. Additionally, abundant AR mRNA expression is shown for the first time in the inner ear of a vertebrate. The distribution of AR mRNA strongly supports the role of androgens as modulators of behaviorally defined vocal, auditory, and neuroendocrine circuits in teleost fish and vertebrates in general. 2009 Wiley-Liss, Inc.

Channel catfish (Ictalurus punctatus) leukocytes express estrogen receptor isoforms ERα and ERβ2 and are functionally modulated by estrogens.

PubMed

Iwanowicz, Luke R; Stafford, James L; Patiño, Reynaldo; Bengten, Eva; Miller, Norman W; Blazer, Vicki S

2014-09-01

Estrogens are recognized as modulators of immune responses in mammals and teleosts. While it is known that the effects of estrogens are mediated via leukocyte-specific estrogen receptors (ERs) in humans and mice, leucocyte-specific estrogen receptor expression and the effects of estrogens on this cell population is less explored and poorly understood in teleosts. Here in, we verify that channel catfish (Ictalurus punctaus) leukocytes express ERα and ERβ2. Transcripts of these isoforms were detected in tissue-associated leukocyte populations by PCR, but ERβ2 was rarely detected in PBLs. Expression of these receptors was temporally regulated in PBLs following polyclonal activation by concanavalin A, lipopolysaccharide or alloantigen based on evaluation by quantitative and end-point PCR. Examination of long-term leukocyte cell lines demonstrated that these receptors are differentially expressed depending on leukocyte lineage and phenotype. Expression of ERs was also temporally dynamic in some leukocyte lineages and may reflect stage of cell maturity. Estrogens affect the responsiveness of channel catfish peripheral blood leukocytes (PBLs) to mitogens in vitro. Similarly, bactericidal activity and phorbol 12-myristate 13-acetate induced respiratory burst was modulated by 17β-estradiol. These actions were blocked by the pure ER antagonist ICI 182780 indicating that response is, in part, mediated via ERα. In summary, estrogen receptors are expressed in channel catfish leukocytes and participate in the regulation of the immune response. This is the first time leukocyte lineage expression has been reported in teleost cell lines. Published by Elsevier Ltd.

Adaptive evolution of voltage-gated sodium channels: The first 800 million years

PubMed Central

Zakon, Harold H.

2012-01-01

Voltage-gated Na+-permeable (Nav) channels form the basis for electrical excitability in animals. Nav channels evolved from Ca2+ channels and were present in the common ancestor of choanoflagellates and animals, although this channel was likely permeable to both Na+ and Ca2+. Thus, like many other neuronal channels and receptors, Nav channels predated neurons. Invertebrates possess two Nav channels (Nav1 and Nav2), whereas vertebrate Nav channels are of the Nav1 family. Approximately 500 Mya in early chordates Nav channels evolved a motif that allowed them to cluster at axon initial segments, 50 million years later with the evolution of myelin, Nav channels “capitalized” on this property and clustered at nodes of Ranvier. The enhancement of conduction velocity along with the evolution of jaws likely made early gnathostomes fierce predators and the dominant vertebrates in the ocean. Later in vertebrate evolution, the Nav channel gene family expanded in parallel in tetrapods and teleosts (∼9 to 10 genes in amniotes, 8 in teleosts). This expansion occurred during or after the late Devonian extinction, when teleosts and tetrapods each diversified in their respective habitats, and coincided with an increase in the number of telencephalic nuclei in both groups. The expansion of Nav channels may have allowed for more sophisticated neural computation and tailoring of Nav channel kinetics with potassium channel kinetics to enhance energy savings. Nav channels show adaptive sequence evolution for increasing diversity in communication signals (electric fish), in protection against lethal Nav channel toxins (snakes, newts, pufferfish, insects), and in specialized habitats (naked mole rats). PMID:22723361

Transcriptome display during tilapia sex determination and differentiation as revealed by RNA-Seq analysis.

PubMed

Tao, Wenjing; Chen, Jinlin; Tan, Dejie; Yang, Jing; Sun, Lina; Wei, Jing; Conte, Matthew A; Kocher, Thomas D; Wang, Deshou

2018-05-15

The factors determining sex in teleosts are diverse. Great efforts have been made to characterize the underlying genetic network in various species. However, only seven master sex-determining genes have been identified in teleosts. While the function of a few genes involved in sex determination and differentiation has been studied, we are far from fully understanding how genes interact to coordinate in this process. To enable systematic insights into fish sexual differentiation, we generated a dynamic co-expression network from tilapia gonadal transcriptomes at 5, 20, 30, 40, 90, and 180 dah (days after hatching), plus 45 and 90 dat (days after treatment) and linked gene expression profiles to both development and sexual differentiation. Transcriptomic profiles of female and male gonads at 5 and 20 dah exhibited high similarities except for a small number of genes that were involved in sex determination, while drastic changes were observed from 90 to 180 dah, with a group of differently expressed genes which were involved in gonadal differentiation and gametogenesis. Weighted gene correlation network analysis identified changes in the expression of Borealin, Gtsf1, tesk1, Zar1, Cdn15, and Rpl that were correlated with the expression of genes previously known to be involved in sex differentiation, such as Foxl2, Cyp19a1a, Gsdf, Dmrt1, and Amh. Global gonadal gene expression kinetics during sex determination and differentiation have been extensively profiled in tilapia. These findings provide insights into the genetic framework underlying sex determination and sexual differentiation, and expand our current understanding of developmental pathways during teleost sex determination.

A New Model Army: Emerging fish models to study the genomics of vertebrate Evo-Devo

PubMed Central

Braasch, Ingo; Peterson, Samuel M.; Desvignes, Thomas; McCluskey, Braedan M.; Batzel, Peter; Postlethwait, John H.

2014-01-01

Many fields of biology – including vertebrate Evo-Devo research – are facing an explosion of genomic and transcriptomic sequence information and a multitude of fish species are now swimming in this ‘genomic tsunami’. Here, we first give an overview of recent developments in sequencing fish genomes and transcriptomes that identify properties of fish genomes requiring particular attention and propose strategies to overcome common challenges in fish genomics. We suggest that the generation of chromosome-level genome assemblies - for which we introduce the term ‘chromonome’ – should be a key component of genomic investigations in fish because they enable large-scale conserved synteny analyses that inform orthology detection, a process critical for connectivity of genomes. Orthology calls in vertebrates, especially in teleost fish, are complicated by divergent evolution of gene repertoires and functions following two rounds of genome duplication in the ancestor of vertebrates and a third round at the base of teleost fish. Second, using examples of spotted gar, basal teleosts, zebrafish-related cyprinids, cavefish, livebearers, icefish, and lobefin fish, we illustrate how next generation sequencing technologies liberate emerging fish systems from genomic ignorance and transform them into a new model army to answer longstanding questions on the genomic and developmental basis of their biodiversity. Finally, we discuss recent progress in the genetic toolbox for the major fish models for functional analysis, zebrafish and medaka, that can be transferred to many other fish species to study in vivo the functional effect of evolutionary genomic change as Evo-Devo research enters the postgenomic era. PMID:25111899

Hepcidin-Dependent Regulation of Erythropoiesis during Anemia in a Teleost Fish, Dicentrarchus labrax

PubMed Central

Caldas, Carolina; Ramos, Miguel F.; Rodrigues, Pedro N. S.

2016-01-01

Anemia is a common disorder, characterized by abnormally low levels of red blood cells or hemoglobin. The mechanisms of anemia development and response have been thoroughly studied in mammals, but little is known in other vertebrates, particularly teleost fish. In this study, different degrees of anemia were induced in healthy European sea bass specimens (Dicentrarchus labrax) and at pre-determined time points hematological parameters, liver iron content and the expression of genes involved in iron homeostasis and hematopoiesis, with particular attention on hepcidins, were evaluated. The experimental anemia prompted a decrease in hamp1 expression in all tested organs, in accordance to an increased need for iron absorption and mobilization, with slight increases in hamp2 in the kidney and intestine. The liver was clearly the major organ involved in iron homeostasis, decreasing its iron content and showing a gene expression profile consistent with an increased iron release and mobilization. Although both the spleen and head kidney are involved in erythropoiesis, the spleen was found to assume a more preponderant role in the recovery of erythrocyte levels. The intestine was also involved in the response to anemia, through the increase of iron transporting genes. Administration of Hamp1 or Hamp2 mature peptides showed that only Hamp1 affects hematological parameters and liver iron content. In conclusion, the molecular mechanisms of response to anemia present in sea bass are similar to the ones described for mammals, with these results indicating that the two hepcidin types from teleosts assume different roles during anemia. PMID:27100629

Characterization of a hypoxia-response element in the Epo locus of the pufferfish, Takifugu rubripes.

PubMed

Kulkarni, Rashmi P; Tohari, Sumanty; Ho, Adrian; Brenner, Sydney; Venkatesh, Byrappa

2010-06-01

Animals respond to hypoxia by increasing synthesis of the glycoprotein hormone erythropoietin (Epo) which in turn stimulates the production of red blood cells. The gene encoding Epo has been recently cloned in teleost fishes such as the pufferfish Takifugu rubripes (fugu) and zebrafish (Danio rerio). It has been shown that the transcription levels of Epo in teleost fishes increase in response to anemia or hypoxia in a manner similar to its human ortholog. However, the cis-regulatory element(s) mediating the hypoxia response of Epo gene in fishes has not been identified. In the present study, using the human hepatoma cell line (Hep3B), we have identified and characterized a hypoxia response element (HRE) in the fugu Epo locus. The sequence of the fugu HRE (ACGTGCTG) is identical to that of the HRE in the human EPO locus. However, unlike the HRE in the mammalian Epo locus, which is located in the 3' region of the gene, the fugu HRE is located in the 5' flanking region and on the opposite strand of DNA. This HRE is conserved in other teleosts such as Tetraodon and zebrafish in a similar location. A 365-bp fragment containing the fugu HRE was able to drive GFP expression in the liver of transgenic zebrafish. However, we could not ascertain if the expression of transgene is induced by hypoxia in vivo due to the low and variable levels of GFP expression in transgenic zebrafish. Our investigations also revealed that the Epo locus has experienced extensive rearrangements during vertebrate evolution. Copyright © 2010 Elsevier B.V. All rights reserved.

Corticosteroid receptor gene expression is related to sex and social behaviour in a social fish.

PubMed

O'Connor, Constance M; Rodela, Tammy M; Mileva, Viktoria R; Balshine, Sigal; Gilmour, Kathleen M

2013-03-01

Circulating corticosteroids have been related to social status in a variety of species. However, our understanding of corticosteroid receptor expression and its relationship with sociality is still in its infancy. Knowledge of variation in receptor expression is critical to understand the physiological relevance of differences in circulating corticosteroid concentrations. In this study, we examined corticosteroid receptor gene expression in relation to dominance rank, sex, and social behaviour in the highly social cichlid fish, Neolamprologus pulcher. We examined the relative gene expression of the three known teleost corticosteroid receptors: glucocorticoid receptor 1 (GR1), glucocorticoid receptor 2 (GR2), and the mineralocorticoid receptor (MR) in liver and brain tissue of dominant and subordinate N. pulcher males and females. Phylogenetic analysis revealed the N. pulcher gene originally described as GR2, clustered with other teleost GR1 genes, while the originally-described N. pulcher GR1 gene clustered with the GR2 genes of other teleosts. Therefore we propose a change in the original nomenclature of the N. pulcher GRs: GR1 (formerly GR2) and GR2 (formerly GR1) and adopt this new nomenclature throughout this manuscript. Liver MR transcript levels were higher in males than females, and positively related to submissive behaviour. Liver GR2 (formerly GR1) transcript levels were also higher in males than females. Collectively, the results demonstrate sex differences in corticosteroid receptor abundance, and suggest tissue- and receptor-specific roles for corticosteroid receptors in mediating aspects of social behaviour. Copyright © 2012. Published by Elsevier Inc.

Sex change strategy and the aromatase genes.

PubMed

Gardner, L; Anderson, T; Place, A R; Dixon, B; Elizur, A

2005-04-01

Sequential hermaphroditism is a common reproductive strategy in many teleosts. Steroid production is known to mediate both the natural and induced sex change, yet beyond this the physiology directing this process has received little attention. Cytochrome P450 aromatase is a key enzyme in the hormonal pathway catalysing the conversion of sex steroids, androgens to oestrogens, and thus is highly relevant to the process of sex change. This study reports the isolation of cDNA sequences for aromatase isoforms CYP19A1 and CYP19A2 from teleost species representing three forms of sexual hermaphroditism: Lates calcarifer (protandry), Cromileptes altivelis (protogyny), and Gobiodon histrio (bi-directional). Deduced amino acid analysis of these isoforms with other reported isoforms from gonochoristic (single sex) teleosts revealed 56-95% identity within the same isoform while only 48-65% identity between isoforms irrespective of species and sexual strategy. Phylogenetic analysis supported this result separating sequences into isoform exclusive clades in spite of species apparent evolutionary distance. Furthermore, this study isolates 5' flanking regions of all above genes and describes putative cis-acting elements therein. Elements identified include steroidogenic factor 1 binding site (SF-1), oestrogen response element (ERE), progesterone response element (PRE), androgen response element (ARE), glucocorticoid response elements (GRE), peroxisome proliferator-activated receptor alpha/retinoid X receptor alpha heterodimer responsive element (PPARalpha/RXRalpha), nuclear factor kappabeta (NF-kappabeta), SOX 5, SOX 9, and Wilms tumor suppressor (WTI). A hypothetical in vivo model was constructed for both isoforms highlighting potential roles of these putative cis-acting elements with reference to normal function and sexual hermaphroditism.

Extra-gonadal steroids modulate non-breeding territorial aggression in weakly electric fish.

PubMed

Jalabert, Cecilia; Quintana, Laura; Pessina, Paula; Silva, Ana

2015-06-01

The neuroendocrine control of intraspecific aggression is a matter of current debate. Although aggression in a reproductive context has been associated with high levels of circulating androgens in a broad range of species, it has also been shown to occur during the non-breeding season when gonads are regressed and plasma steroid hormone levels are low. In mammals and birds the aromatization of androgens into estrogens plays a key role in the regulation of aggression in both the breeding and non-breeding seasons. This is the first study in a teleost fish to explore the role of steroids in the modulation of non-breeding aggression. Gymnotus omarorum is a highly aggressive teleost fish that exhibits aggression all year-round. We analyzed male-male non-breeding agonistic behavior, compared circulating 11-Ketotestosterone (11-KT) levels between dominants and isolated males, assessed the regulatory role of aromatization of androgens into estrogens, and evaluated the gonads as a source of these sex steroids. We found that high levels of aggression occurred in the non-breeding season despite low plasma 11-KT levels, and that there was no difference in 11-KT levels between dominant and isolated males. We demonstrated that acute aromatase inhibition decreased aggression, distorted contest dynamics, and affected expected outcome. We also found that castrated individuals displayed aggressive behavior indistinguishable from non-castrated males. Our results show, for the first time in teleost fish, that territorial aggression of G. omarorum during the non-breeding season depends on a non-gonadal estrogenic pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

Diet and condition of mesopredators on coral reefs in relation to shark abundance

PubMed Central

Meekan, Mark G.; Meeuwig, Jessica J.

2017-01-01

Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a “natural experiment” to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing. On reefs where sharks were rare, the gut contents of five species of mesopredatory teleosts largely contained fish while on reefs with abundant sharks, the same mesopredatory species consumed a larger proportion of benthic invertebrates. These measures of diet were correlated with changes in body condition, such that the condition of mesopredatory teleosts was significantly poorer on reefs with higher shark abundance. Condition was defined as body weight, height and width for a given length and also estimated via several indices of condition. Due to the nature of natural experiments, alternative explanations cannot be discounted. However, the results were consistent with the hypothesis that loss of sharks may influence the diet and condition of mesopredators and by association, their fecundity and trophic role. Regardless of the mechanism (risk effects, competitive release, or other), our findings suggest that overfishing of sharks has the potential to trigger trophic cascades on coral reefs and that further declines in shark populations globally should be prevented to protect ecosystem health. PMID:28422965

Evolution of a Functional Head Joint in Deep-Sea Fishes (Stomiidae)

PubMed Central

Johnson, G. David

2017-01-01

The head and anterior trunk region of most actinopterygian fishes is stiffened as, uniquely within vertebrates, the pectoral girdles have a direct and often strong connection through the posttemporal to the posterior region of the skull. Members of the mesopelagic fish family Stomiidae have their pectoral girdle separated from the skull. This connection is lost in several teleost groups, but the stomiids have an additional evolutionary novelty—a flexible connection between the occiput and the first vertebra, where only the notochord persists. Several studies suggested that stomiids engulf significantly large prey items and conjectured about the functional role of the anterior part of the vertebral column; however, there has been no precise anatomical description of this complex. Here we describe a unique configuration comprising the occiput and the notochordal sheath in Aristostomias, Eustomias, Malacosteus, Pachystomias, and Photostomias that represents a true functional head joint in teleosts and discuss its potential phylogenetic implications. In these genera, the chordal sheath is folded inward ventrally beneath its connection to the basioccipital and embraces the occipital condyle when in a resting position. In the resting position (wherein the head is not manipulatively elevated), this condyle is completely embraced by the ventral fold of the notochord. A manual manipulative elevation of the head in cleared and stained specimens unfolds the ventral sheath of the notochord. As a consequence, the cranium can be pulled up and back significantly farther than in all other teleost taxa that lack such a functional head joint and thereby can reach mouth gapes up to 120°. PMID:28146571

Genome specific PPARαB duplicates in salmonids and insights into estrogenic regulation in brown trout.

PubMed

Madureira, Tânia Vieira; Pinheiro, Ivone; de Paula Freire, Rafaelle; Rocha, Eduardo; Castro, Luis Filipe; Urbatzka, Ralph

2017-06-01

Peroxisome proliferator-activated receptors (PPARs) are key regulators of many processes in vertebrates, such as carbohydrate and lipid metabolism. PPARα, a member of the PPAR nuclear receptor gene subfamily (NR1C1), is involved in fatty acid metabolism, namely in peroxisomal β-oxidation. Two gene paralogues, pparαA and pparαB, were described in several teleost species with their origin dating back to the teleost-specific genome duplication (3R). Given the additional salmonid-specific genome duplication (4R), four genes could be theoretically anticipated for this gene subfamily. In this work, we examined the pparα gene repertoire in brown trout, Salmo trutta f. fario. Data disclosed two pparα-like sequences in brown trout. Phylogenetic analyses further revealed that the isolated genes are most likely genome pparαB duplicates, pparαBa and pparαBb, while pparαA is apparently absent in salmonids. Both genes showed a ubiquitous mRNA expression across a panel of 11 different organs. In vitro exposed primary brown trout hepatocytes strongly suggest that pparα gene paralogues are differently regulated by ethinylestradiol (EE2). PparαBb mRNA expression significantly decreased with dosage, reaching significance after exposure to 50μM EE2, while pparαBa mRNA increased, significant at 1μM EE2. The present data enhances the understanding of pparα function and evolution in teleost, and reinforces the evidence of a potential crosstalk between estrogenic and pparα signaling pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Evolutionary transitions in parental care and live bearing in vertebrates.

PubMed Central

Reynolds, John D; Goodwin, Nicholas B; Freckleton, Robert P

2002-01-01

We provide the first review of phylogenetic transitions in parental care and live bearing for a wide variety of vertebrates. This includes new analyses of both numbers of transitions and transition probabilities. These reveal numerous transitions by shorebirds and anurans toward uniparental care by either sex. Whereas most or all of the shorebird transitions were from biparental care, nearly all of the anuran transitions have been from no care, reflecting the prevalence of each form of care in basal lineages in each group. Teleost (bony) fishes are similar to anurans in displaying numerous transitions toward uniparental contributions by each sex. Whereas cichlid fishes have often evolved from biparental care to female care, other teleosts have usually switched from no care to male care. Taxa that have evolved exclusive male care without courtship-role reversal are characterized by male territoriality and low costs of care per brood. Males may therefore benefit from care through female preference of parental ability in these species. Primates show a high frequency of transitions from female care to biparental care, reflecting the prevalence of female care in basal lineages. In the numerous taxa that display live bearing by females, including teleosts, elasmobranchs, squamate reptiles and invertebrates, we find that live bearing has always evolved from a lack of care. Although the transition counts and probabilities will undoubtedly be refined as phylogenetic information and methodologies improve, the overall biases in these taxa should help to place adaptive hypotheses for the evolution of care into a stronger setting for understanding directions of change. PMID:11958696

Spatial distribution and cellular composition of adult brain proliferative zones in the teleost, Gymnotus omarorum

PubMed Central

Olivera-Pasilio, Valentina; Peterson, Daniel A.; Castelló, María E.

2014-01-01

Proliferation of stem/progenitor cells during development provides for the generation of mature cell types in the CNS. While adult brain proliferation is highly restricted in the mammals, it is widespread in teleosts. The extent of adult neural proliferation in the weakly electric fish, Gymnotus omarorum has not yet been described. To address this, we used double thymidine analog pulse-chase labeling of proliferating cells to identify brain proliferation zones, characterize their cellular composition, and analyze the fate of newborn cells in adult G. omarorum. Short thymidine analog chase periods revealed the ubiquitous distribution of adult brain proliferation, similar to other teleosts, particularly Apteronotus leptorhynchus. Proliferating cells were abundant at the ventricular-subventricular lining of the ventricular-cisternal system, adjacent to the telencephalic subpallium, the diencephalic preoptic region and hypothalamus, and the mesencephalic tectum opticum and torus semicircularis. Extraventricular proliferation zones, located distant from the ventricular-cisternal system surface, were found in all divisions of the rombencephalic cerebellum. We also report a new adult proliferation zone at the caudal-lateral border of the electrosensory lateral line lobe. All proliferation zones showed a heterogeneous cellular composition. The use of short (24 h) and long (30 day) chase periods revealed abundant fast cycling cells (potentially intermediate amplifiers), sparse slow cycling (potentially stem) cells, cells that appear to have entered a quiescent state, and cells that might correspond to migrating newborn neural cells. Their abundance and migration distance differed among proliferation zones: greater numbers and longer range and/or pace of migrating cells were associated with subpallial and cerebellar proliferation zones. PMID:25249943

Hypothalamohypophysial vascular and neurosecretory link in the teleost Bagarius bagarius (Ham.).

PubMed

Sathyanesan, A G; Jose, T M

1975-01-01

A three-dimensional picture of the hypothalamohypophysial neurosecretory system of B. bargarius could be obtained by adopting in situ staining techniques. The paired NPO give rise to left and right neurosecretory tracts which, although they approximate as a common tract, maintain their individuality till entering the pars intermedia. The ventral hypothalamic and the hypophysial arteries take their origin from the internal carotid artery. The former contributes to the formation of the primary plexus of the median eminence and the latter enters the pituitary directly, giving rise to the neuroadreno-interface vasculature. The vasculature of the median eminence lies in close contact with the long common neurosecretory tract. Morphological evidence suggests that in B. bagarius there are three pathways of hypothalamic control of the hypophysis: (1) A direct neuroglandular pathway, where the neurosecretory axons come directly in contact with the adrenohypophysial cells. (2) An indirect neurovasculoglandular pathway, where the blood exposed to the NSM at the median eminence comes in contact with gland cells. (3) Another indirect neurovasculoglandular pathway, where the blood is exposed to NSM at the neurohypophysis prior coming in contact with the gland cells. Thus, B. bagarius has the 'median eminence equivalent' neuroadeno-interface vasculature typical of the teleosts and the median eminence comparable to the Elasmobranchs, Holocephali and primitive Actinopterygians. This shows that the pituitary portal system of teleosts is in general agreement with that of other fish groups, except that in some it is restricted to the neuroadreno-interface, whereas in others like B. bagarius it extends to the hypothalamus also. These may be termed anterior and posterior median eminence.

Characterization of TLR5 and TLR9 from silver pomfret (Pampus argenteus) and expression profiling in response to bacterial components.

PubMed

Gao, Quanxin; Yue, Yanfeng; Min, Minghua; Peng, Shiming; Shi, Zhaohong; Sheng, Wenquan; Zhang, Tao

2018-06-08

Toll like receptor (TLR) 5 and 9 are important members of the TLR family that play key roles in innate immunity in all vertebrates. In this study, paTLR5 and paTLR9 were identified in silver pomfret (Pampus argenteus), a marine teleost of great economic value. Open reading frames (ORFs) of paTLR5 and paTLR9 are 2646 and 3225 bp, encoding polypeptides of 881 and 1074 amino acids, respectively. Sequence analysis revealed several conserved characteristic features, including signal peptides, leucine-rich repeat (LRR) motifs, and a Toll/interleukin-I receptor (TIR) domain. Sequence, phylogenetic and synteny analysis revealed high sequence identity with counterparts in other teleosts, confirming their correct nomenclature and conservation during evolution. Quantitative real-time PCR revealed that the that both TLRs were ubiquitously expressed in all investigated tissues, most abundantly in liver, kidney, spleen, intestine and gill, but lower in muscle and skin. In vitro immunostimulation experiments revealed that Aeromonas hydrophila lipopolysaccharide (LPS) and Vibrio anguillarum flagellin induced higher levels of paTLR9 and paTLR5 mRNA expression in isolated fish intestinal epithelial cells (FIECs) than Lactobacillus plantarum lipoteichoic acid (LTA), but all increased the secretion of IL-6 and TNF-α and induced cell apoptosis and necrosis. Together, these results indicate that paTLR5 and paTLR9 may function in the response to bacterial pathogens. Our findings enhance our understanding of the function of TLRs in the innate immune system of silver pomfret and other teleosts. Copyright © 2018. Published by Elsevier Ltd.

Escape manoeuvres in the spiny dogfish (Squalus acanthias).

PubMed

Domenici, Paolo; Standen, Emily M; Levine, Robert P

2004-06-01

The locomotor performance of dogfish during escape responses was observed by means of high-speed video. Dogfish show C-type escape responses that are comparable with those shown previously in teleosts. Dogfish show high variability of turning rates of the anterior part of the body (head to centre of mass), i.e. with peak values from 434 to 1023 deg. s(-1). We suggest that this variability may be due to the presence of two types of escape manoeuvres, i.e. responses with high and low turning rates, as previously found in a teleost species. Fast responses (i.e. with high maximum turning rates, ranging between 766 and 1023 deg. s(-1)) showed significantly higher locomotor performance than slow responses (i.e. with low maximum turning rates, ranging between 434 and 593 deg. s(-1)) in terms of distance covered, speed and acceleration, although no differences were found in the turning radius of the centre of mass during the escape manoeuvres. The existence of two types of escape responses would have implications in terms of both neural control and muscular activation patterns. When compared with literature data for the locomotor performance of bony fishes, dogfish showed relatively low speed and acceleration, comparable turning rates and a turning radius that is in the low part of the range when compared with teleosts, indicating relatively high manoeuvrability. The locomotor performance observed in dogfish is consistent with their morphological characteristics: (1) low locomotor performance associated with low thrust developed by their relatively small posterior depth of section and (2) relatively high manoeuvrability associated with their high flexibility.

Diet and condition of mesopredators on coral reefs in relation to shark abundance.

PubMed

Barley, Shanta C; Meekan, Mark G; Meeuwig, Jessica J

2017-01-01

Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a "natural experiment" to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing. On reefs where sharks were rare, the gut contents of five species of mesopredatory teleosts largely contained fish while on reefs with abundant sharks, the same mesopredatory species consumed a larger proportion of benthic invertebrates. These measures of diet were correlated with changes in body condition, such that the condition of mesopredatory teleosts was significantly poorer on reefs with higher shark abundance. Condition was defined as body weight, height and width for a given length and also estimated via several indices of condition. Due to the nature of natural experiments, alternative explanations cannot be discounted. However, the results were consistent with the hypothesis that loss of sharks may influence the diet and condition of mesopredators and by association, their fecundity and trophic role. Regardless of the mechanism (risk effects, competitive release, or other), our findings suggest that overfishing of sharks has the potential to trigger trophic cascades on coral reefs and that further declines in shark populations globally should be prevented to protect ecosystem health.

Evolution of the Mauthner axon cap.

PubMed

Bierman, Hilary S; Zottoli, Steven J; Hale, Melina E

2009-01-01

Studies of vertebrate brain evolution have focused primarily on patterns of gene expression or changes in size and organization of major brain regions. The Mauthner cell, an important reticulospinal neuron that functions in the startle response of many species, provides an opportunity for evolutionary comparisons at the cellular level. Despite broad interspecific similarities in Mauthner cell morphology, the motor patterns and startle behaviors it initiates vary markedly. Response diversity has been hypothesized to result, in part, from differences in the structure and function of the Mauthner cell-associated axon cap. We used light microscopy techniques to compare axon cap morphology across a wide range of species, including all four extant basal actinopterygian orders, representatives of a variety of teleost lineages and lungfishes, and we combined our data with published descriptions of axon cap structure. The 'composite' axon cap, observed in teleosts, is an organized conglomeration of glia and fibers of inhibitory and excitatory interneurons. Lungfish, amphibian tadpoles and several basal actinopterygian fishes have 'simple' axon caps that appear to lack glia and include few fibers. Several other basal actinopterygian fishes have 'simple-dense' caps that include greater numbers of fibers than simple caps, but lack the additional elements and organization of composite caps. Phylogenetic mapping shows that through evolution there are discrete transitions in axon cap morphology occurring at the base of gnathostomes, within basal actinopterygians, and at the base of the teleost radiation. Comparing axon cap evolution to the evolution of startle behavior and motor pattern provides insight into the relationship between Mauthner cell-associated structures and their functions in behavior. Copyright 2009 S. Karger AG, Basel.

Evolutionary growth process of highly conserved sequences in vertebrate genomes.

PubMed

Ishibashi, Minaka; Noda, Akiko Ogura; Sakate, Ryuichi; Imanishi, Tadashi

2012-08-01

Genome sequence comparison between evolutionarily distant species revealed ultraconserved elements (UCEs) among mammals under strong purifying selection. Most of them were also conserved among vertebrates. Because they tend to be located in the flanking regions of developmental genes, they would have fundamental roles in creating vertebrate body plans. However, the evolutionary origin and selection mechanism of these UCEs remain unclear. Here we report that UCEs arose in primitive vertebrates, and gradually grew in vertebrate evolution. We searched for UCEs in two teleost fishes, Tetraodon nigroviridis and Oryzias latipes, and found 554 UCEs with 100% identity over 100 bps. Comparison of teleost and mammalian UCEs revealed 43 pairs of common, jawed-vertebrate UCEs (jUCE) with high sequence identities, ranging from 83.1% to 99.2%. Ten of them retain lower similarities to the Petromyzon marinus genome, and the substitution rates of four non-exonic jUCEs were reduced after the teleost-mammal divergence, suggesting that robust conservation had been acquired in the jawed vertebrate lineage. Our results indicate that prototypical UCEs originated before the divergence of jawed and jawless vertebrates and have been frozen as perfect conserved sequences in the jawed vertebrate lineage. In addition, our comparative sequence analyses of UCEs and neighboring regions resulted in a discovery of lineage-specific conserved sequences. They were added progressively to prototypical UCEs, suggesting step-wise acquisition of novel regulatory roles. Our results indicate that conserved non-coding elements (CNEs) consist of blocks with distinct evolutionary history, each having been frozen since different evolutionary era along the vertebrate lineage. Copyright © 2012 Elsevier B.V. All rights reserved.

Elevated carbon dioxide alters the plasma composition and behaviour of a shark.

PubMed

Green, Leon; Jutfelt, Fredrik

2014-09-01

Increased carbon emissions from fossil fuels are increasing the pCO2 of the ocean surface waters in a process called ocean acidification. Elevated water pCO2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks (Scyliorhinus canicula) to either control conditions or a year 2100 scenario of 990 μatm pCO2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated pCO2 group buffered internal acidosis via [Formula: see text] accumulation with an associated increase in Na(+), indicating that the blood chemistry remained altered despite the long acclimation period. The elevated pCO2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO2-exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO2-exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO2, as in some teleosts, or that the sharks detect CO2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Retinal Processing: Polarization Vision in Teleost Fishes

DTIC Science & Technology

2005-07-26

conspecific visual communication network utilizing polarized light signals in the coral reef environment. These observations have provoked interest in the... visual communication net- reflection off non-metallic substrates produces predom- work utilizing polarized light signals in the coral reef inantly

Water-Bearing Rocks in Noctis Labyrinthus

NASA Image and Video Library

2014-07-30

Many of the depressions in Noctis Labyrinthus contain water-bearing minerals, suggesting that water was available and persistent in this region during the Late Hesperian to Amazonian epochs on Mars, as seen by NASA Mars Reconnaissance Orbiter.

The endocrinology of stress in fish: an environmental perspective.

PubMed

Pankhurst, N W

2011-01-15

Much of the understanding of the endocrine basis of stress in fish comes from studies of cultured stocks of teleosts; there is comparatively little information on stress responses in wild stock, and less still on chondrosteans and elasmobranchs. This understanding is being refined through increasing understanding of molecular processes underlying endocrine events, with molecular tools offering ready examination of parts of the endocrine pathway that have been resistant to easy measurement of hormone products. An assessment of the timecourse of activation of the hypothalamic-pituitary-interrenal axis shows generally strong independence of temperature, with most teleosts showing measurable increase in plasma cortisol within 10 min of stress. Chondrostean and elasmobranch responses are less well described, but in chondrosteans at least, the response pattern appears to be similar to teleosts. The short latency for increases in corticosteroids following exposure to a stressor means that sampling of wild fish needs to occur rapidly after encounter. Several techniques including underwater sampling and rapid line capture are suitable for this, as is measurement of steroid release to the water by undisturbed fish, albeit possibly with a reduced range of applications. Basal cortisol values in wild teleosts are typically <10 ng mL(-1), but a number of species show values orders of magnitude higher in unstressed fish. Variability in corticosteroid levels arises from a range of factors in addition to stress including, sex and maturity, time of day or since feeding, and season. These factors need to be understood for the sensible assessment of stress responses in wild fish. Studies on free-living birds suggest that environmental stress resides mainly around unpredictable change, and the limited data available for fish support this view. The effect of unpredictable event such as floods or storms are difficult to assess in wild fish due to the difficulty in sampling at these times, and would be predicted to impose environmental stress as in terrestrial systems; however, this has yet to be demonstrated. There is scope for use of stress responses to be used as a measure of environmental quality but only if the basic response to environmental stress is well understood first. Development of this understanding remains a priority for this field of research. Copyright © 2010 Elsevier Inc. All rights reserved.

Contrasted accumulation patterns of persistent organic pollutants and mercury in sympatric tropical dolphins from the south-western Indian Ocean

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

Dirtu, Alin C.; Department of Chemistry, “Al. I. Cuza” University of Iasi, 700506 Iasi; Malarvannan, Govindan

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the contamination with persistent organic pollutants (POPs) and total mercury (T-Hg) of spinner (Stenella longirostris, n =21) and Indo-Pacific bottlenose dolphins (Tursiops aduncus, n=32) sampled from the coastal waters of La Réunion (south-western Indian Ocean). In addition, seven co-occurring teleost fish species were sampled and analyzed as well. Blubber samples from living dolphins and muscle from teleosts were analyzed for polychlorinated biphenyls (PCBs), DDT and metabolites (DDTs), chlordanes (CHLs), hexachlorocyclohexanes (HCHs),more » hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). Methoxylated PBDEs (MeO-PBDEs), reported as having a natural origin, were also analyzed. T-Hg levels were measured in blubber and skin biopsies of the two dolphin species. Stable isotopes δ{sup 13}C and δ{sup 15}N values were determined in skin of the dolphins and in the muscle of teleosts. For PCBs, HCHs and T-Hg, concentrations were significantly higher in T. aduncus than in S. longirostris. For other POP levels, intra-species variability was high. MeO-PBDEs were the dominant compounds (55% of the total POPs) in S. longirostris, while PCBs dominated (50% contribution) in T. aduncus. Other contaminants showed similar profiles between the two species. Given the different patterns of POPs and T-Hg contamination and the δ{sup 15}N values observed among analyzed teleosts, dietary and foraging habitat preferences most likely explain the contrasted contaminant profiles observed in the two dolphin species. Levels of each class of contaminants were significantly higher in males than females. Despite their spatial and temporal overlap in the waters of La Réunion, S. longirostris and T. aduncus are differently exposed to contaminant accumulation. - Highlights: • POPs and total Hg were measured in spinner and bottlenose dolphins from La Réunion. • Levels of PCBs, PBDEs and T-Hg were lower in spinner than in bottlenose dolphins. • Contrasted contaminant profiles were observed between the two dolphin species. • Profiles are most likely explained by dietary and foraging habitat preferences.« less

Quantitative proteomics in teleost fish: insights and challenges for neuroendocrine and neurotoxicology research.

PubMed

Martyniuk, Christopher J; Popesku, Jason T; Chown, Brittany; Denslow, Nancy D; Trudeau, Vance L

2012-05-01

Neuroendocrine systems integrate both extrinsic and intrinsic signals to regulate virtually all aspects of an animal's physiology. In aquatic toxicology, studies have shown that pollutants are capable of disrupting the neuroendocrine system of teleost fish, and many chemicals found in the environment can also have a neurotoxic mode of action. Omics approaches are now used to better understand cell signaling cascades underlying fish neurophysiology and the control of pituitary hormone release, in addition to identifying adverse effects of pollutants in the teleostean central nervous system. For example, both high throughput genomics and proteomic investigations of molecular signaling cascades for both neurotransmitter and nuclear receptor agonists/antagonists have been reported. This review highlights recent studies that have utilized quantitative proteomics methods such as 2D differential in-gel electrophoresis (DIGE) and isobaric tagging for relative and absolute quantitation (iTRAQ) in neuroendocrine regions and uses these examples to demonstrate the challenges of using proteomics in neuroendocrinology and neurotoxicology research. To begin to characterize the teleost neuroproteome, we functionally annotated 623 unique proteins found in the fish hypothalamus and telencephalon. These proteins have roles in biological processes that include synaptic transmission, ATP production, receptor activity, cell structure and integrity, and stress responses. The biological processes most represented by proteins detected in the teleost neuroendocrine brain included transport (8.4%), metabolic process (5.5%), and glycolysis (4.8%). We provide an example of using sub-network enrichment analysis (SNEA) to identify protein networks in the fish hypothalamus in response to dopamine receptor signaling. Dopamine signaling altered the abundance of proteins that are binding partners of microfilaments, integrins, and intermediate filaments, consistent with data suggesting dopaminergic regulation of neuronal stability and structure. Lastly, for fish neuroendocrine studies using both high-throughput genomics and proteomics, we compare gene and protein relationships in the hypothalamus and demonstrate that correlation is often poor for single time point experiments. These studies highlight the need for additional time course analyses to better understand gene-protein relationships and adverse outcome pathways. This is important if both transcriptomics and proteomics are to be used together to investigate neuroendocrine signaling pathways or as bio-monitoring tools in ecotoxicology. Copyright © 2011 Elsevier Inc. All rights reserved.

Rapid method for the measurement of circulating thyroid hormones in low volumes of teleost fish plasma by LC-ESI/MS/MS

PubMed Central

Noyes, Pamela D.; Lema, Sean C.; Roberts, Simon C.; Cooper, Ellen M.

2014-01-01

Thyroid hormones are critical regulators of normal development and physiological functioning in all vertebrates. Radioimmunoassay (RIA) approaches have been the method of choice for measuring circulating levels of thyroid hormones in vertebrates. While sensitive, RIA-based approaches only allow for a single analyte measurement per assay, can lack concordance across platforms and laboratories, and can be prone to analytical interferences especially when used with fish plasma. Ongoing advances in liquid chromatography tandem mass spectrometry (LC/MS/MS) have led to substantial decreases in detection limits for thyroid hormones and other biomolecules in complex matrices, including human plasma. Despite these advances, current analytical approaches do not allow for the measurement of native thyroid hormone in teleost fish plasma by mass spectrometry and continue to rely on immunoassay. In this study, we developed a new method that allows for the rapid extraction and simultaneous measurement of total T4 (TT4) and total T3 (TT3) in low volumes (50 μL) of fish plasma by LC/MS/MS. Methods were optimized initially in plasma from rainbow trout (Oncorhynchus mykiss) and applied to plasma from other teleost fishes, including fathead minnows (Pimephales promelas), mummichogs (Fundulus heteroclitus), sockeye salmon (Oncorhynchus nerka), and coho salmon (Oncorhynchus kisutch). Validation of method performance with T4- and T3-spiked rainbow trout plasma at 2 and 4 ng/mL produced mean recoveries ranging from 82 to 95 % and 97 to 105 %, respectively. Recovery of 13C12-T4 internal standard in plasma extractions was: 99±1.8 % in rainbow trout, 85±11 % in fathead minnow, 73±5.0 % in mummichog, 73±1.7 % in sockeye salmon, and 80±8.4 % in coho salmon. While absolute levels of thyroid hormones measured in identical plasma samples by LC/MS/MS and RIA varied depending on the assay used, T4/T3 ratios were generally consistent across both techniques. Less variability was measured among samples subjected to LC/MS/MS suggesting a more precise estimate of thyroid hormone homeostasis in the species targeted. Overall, a sensitive and reproducible method was established that takes advantage of LC/MS/MS techniques to rapidly measure TT4 and TT3 with negligible interferences in low volumes of plasma across a variety of teleost fishes. PMID:24343452

Evolution of the angiopoietin-like gene family in teleosts and their role in skin regeneration.

PubMed

Costa, Rita A; Cardoso, João C R; Power, Deborah M

2017-01-13

The skin in vertebrates is a protective barrier and damage is rapidly repaired to re-establish barrier function and maintain internal homeostasis. The angiopoietin-like (ANGPTL) proteins are a family of eight secreted glycoproteins with an important role in skin repair and angiogenesis in humans. In other vertebrates their existence and role in skin remains largely unstudied. The present study characterizes for the first time the homologues of human ANGPTLs in fish and identifies the candidates that share a conserved role in skin repair using a regenerating teleost skin model over a 4-day healing period. Homologues of human ANGPTL1-7 were identified in fish, although ANGPTL8 was absent and a totally new family member designated angptl9 was identified in fish and other non-mammalian vertebrates. In the teleost fishes a gene family expansion occurred but all the deduced Angptl proteins retained conserved sequence and structure motifs with the human homologues. In sea bream skin angptl1b, angptl2b, angptl4a, angptl4b and angptl7 transcripts were successfully amplified and they were differentially expressed during skin regeneration. In the first 2 days of skin regeneration, re-establishment of the physical barrier and an increase in the number of blood vessels was observed. During the initial stages of skin regeneration angptl1b and angptl2b transcripts were significantly more abundant (p < 0.05) than in intact skin and angptl7 transcripts were down-regulated (p < 0.05) throughout the 4-days of skin regeneration that was studied. No difference in angptl4a and angptl4b transcript abundance was detected during regeneration or between regenerating and intact skin. The angptl gene family has expanded in teleost genomes. In sea bream, changes in the expression of angptl1b, angptl2b and angptl7 were correlated with the main phases of skin regeneration, indicating the involvement of ANGPTL family members in skin regeneration has been conserved in the vertebrates. Exploration of the fish angptl family in skin sheds new light on the understanding of the molecular basis of skin regeneration an issue of importance for disease control in aquaculture.

Genomic identification and molecular characterization of a non-mammalian TNFAIP8L2 gene from Oplegnathus fasciatus.

PubMed

Umasuthan, Navaneethaiyer; Revathy, Kasthuri Saranya; Whang, Ilson; Kim, Eunmi; Oh, Myung-Joo; Jung, Sung-Ju; Lee, Jeong-Ho; Park, Hae-Chul; Lee, Jehee

2014-05-25

Tumor necrosis factor alpha-induced protein 8-like 2 (TNFAIP8L2) is a newly described negative immune regulator, whose enigmatic biological functions are not clearly understood. In the present study, the TNFAIP8L2 homolog of rock bream (Oplegnathus fasciatus) was identified and characterized. The genomic composition of rock bream TNFAIP8L2 (~6.7 kb) represented a tripartite arrangement in which three exons are interrupted by two introns. The rock bream TNFAIP8L2 transcript (1974 bp) possessed a coding sequence of 561 bp encoding a peptide of 186 amino acids. The predicted rock bream TNFAIP8L2 protein was 21.1kDa and revealed the typical features of known TNFAIP8L2 members including the DED-like domain. Rock bream TNFAIP8L2 was composed of six α-helices and demonstrated a distinct folding pattern of the TNFAIP8L2 family. It showed a certain degree of homology and phylogenetic relationship with the corresponding tilapia counterpart. Based on an interspecies genomic organizational comparison of TNFAIP8L2 orthologs, they could be classified into two classes, with teleost and non-teleost origin respectively. While teleost TNFAIP8L2s manifest a tripartite arrangement, non-teleost counterparts demonstrate a dipartite structure suggesting the loss of an intron during the post-piscine speciation. Promoter proximal region of rock bream TNFAIP8L2 consisted of multiple immune responsive cis-regulatory elements. Analysis of basal transcription in eleven tissues revealed its constitutive expression in examined tissues with highest magnitude in the head kidney. The modulated temporal mRNA expression of rock bream TNFAIP8L2 in head kidney post-challenges with stimulants (LPS and poly I:C) and pathogens (Streptococcus iniae and irido virus) was stimulant-specific. Additionally, a drastic down-regulation of rock bream TNFAIP8L2 mRNA level occurred in blood cells collected from experimentally injured animals, and it was accompanied by a contemporaneous down-regulation of cytokines, TNF-α and TGFβ3. All these findings imply that rock bream TNFAIP8L2 is potentially responsible for immune and inflammatory modulation in rock bream. Copyright © 2014 Elsevier B.V. All rights reserved.

Predicting anthropogenic soils across the Amazonia

NASA Astrophysics Data System (ADS)

Mcmichael, C.; Palace, M. W.; Bush, M. B.; Braswell, B. H.; Hagen, S. C.; Silman, M.; Neves, E.; Czarnecki, C.

2012-12-01

Hidden under the forest canopy in lowland Amazonia are nutrient-enriched soils, called terra pretas (or Amazonian black earths), which were formed by prehistoric indigenous populations. These anthrosols are in stark contrast to typical nutrient-poor Amazonian soils, and have retained increased nutrient levels for hundreds of years. Because of their long-term nutrient retaining ability, terra pretas may be crucial for developing sustainable agricultural practices in Amazonia, especially given the deforestation necessary for traditional slash-and-burn systems. However, the frequency and distribution of terra preta soils across the landscape remains debatable, and archaeologists have estimated that terra pretas cover anywhere from 0.1% to 10% of the lowland Amazonian forests. The highest concentration of terra preta soils has been found along the central and eastern portions of the Amazon River and its major tributaries, but whether this is a true pattern or simply reflects sampling bias remains unknown. A possible explanation is that specific environmental or biotic conditions were preferred for human settlement and terra preta formation. Here, we use environmental parameters to predict the probabilities of terra preta soils across lowland Amazonian forests. We compiled a database of 2708 sites across Amazonia, including locations that contain terra pretas (n = 917), and those that are known to be terra preta-free (n = 1791). More than 20 environmental variables, including precipitation, elevation, slope, soil fertility, and distance to river were converted into 90-m resolution raster images across Amazonia and used to model the probability of terra preta occurrence. The relationship between the predictor variables and the occurrence of terra preta was examined using three modeling techniques: logistic regression, auto-logistic regression, and maximum entropy estimations. All three techniques provided similar predictions for terra preta distributions and the amount of area covered by terra preta. Distance to river, locations of bluffs, elevation, and soil fertility were important factors in determining distributions of terra preta, while other environmental variables had less effect. Terra pretas were most likely to be found in central and eastern Amazonia near the confluences of the Amazon River and its major tributaries. Within this general area of higher probability, terra pretas are most likely found atop the bluffs overlooking the rivers as opposed to lying on the floodplain. Interestingly, terra pretas are more probable in areas with less-fertile and more highly weathered soils. Although all three modeling techniques provided similar predictions of terra preta across Amazonia, we suggest that maximum entropy modeling is the best technique to predict anthropogenic soils across the vast Amazonian landscape. The auto-logistic regression corrects for spatial autocorrelation inherent to archaeological surveys, but still requires absence data, which was collected at different times and on different spatial scales than the presence data. The maximum entropy model requires presence only data, accounts for spatial autocorrelation, and is not affected by the differential soil sampling techniques.

Martian Weathering Environments of the Amazonian Indicated by Correlated Morphologic and Spectral Observation in Acidalia Planitia

NASA Astrophysics Data System (ADS)

Kraft, M. D.; Rogers, D.; Fergason, R. L.; Michalski, J. R.; Sharp, T. G.

2009-12-01

While much attention has been given to chemical alteration and the state of water on early Mars, it remains important to understand aqueous processes throughout Martian history, including the recent geologic past. It has been suggested that the Amazonian was marked primarily by anhydrous, oxidative weathering because Amazonian surfaces, such as the northern plains, lack hydration features in near-infrared spectra [1]. But high-silica materials (Surface Type 2, ST2) discovered by the Thermal Emission Spectrometer [2] that occur in the northern plains attest to aqueous alteration of silicate minerals. The questions are when did this occur and by what process? ST2 correlates spatially with outflow sediments and high-silica materials may have formed in large amounts of water related to outflow flooding events of the late Hesperian [3,4]. ST2 also may correspond to global ice-rich mantles, indicating formation in icy environments related to geologically recent climate fluctuations [3]. Can these very different mechanisms and environments be discerned? In a global study of TES spectra, Rogers et al. (2007) [5] found significant spectral differences between ST2 surfaces in northern and southern Acidalia Planitia that occur near 40-50° N. Several geomorphic transitions occur across latitudes, and many of these are directly or potentially related to Amazonian periglacial activity and occur in the 40-50° N range. This potential link between composition and periglacial morphology needs further exploration. We examined this relationship from 40-50° N in Acidalia Planitia, using Thermal Emission Imaging System (THEMIS) multispectral data to measure the local spectral properties of the surface. We identified a boundary between two surface spectral types that match closely the spectra of north and south Acidalia derived by Rogers et al. [2007]. This boundary is diffuse, occurring between 47-48° N in our study region in western Acidalia, and correlates with observed morphologic and thermophysical differences. Close examination of those surfaces with High Resolution Imaging Science Experiment (HiRISE) images shows that the area north of the boundary is a modified version of the southern surface, subdued and overprinted by periglacial polygonal ground. Thus, we think that ground ice has modified the surface morphology and, furthermore, that periglacial processing also modified the silicate composition of the northern surface materials. Weathering that created the northern Acidalia composition involved ground ice, and was likely similar to weathering in Antarctic soils, in which silica is mobilized by thin water films and deposited as gels [6]. By this mechanism, aqueous weathering on Mars has probably persisted into, and throughout, the Amazonian. References: [1] Bibring et al. (2006) Science, 312, 400-404. [2] Bandfield et al. (2000) Science, 287, 1626-1630. [3] Wyatt et al. (2004) Geology, 32, 645-648. [4] Tanaka et al. (2005) USGS Sci. Invest. Map 2888. [5] Rogers et al. (2007) J. Geophys. Res.,112, E02004. [6] Ugolini and Anderson (1973), Soil Sci., 105, 461-470.

Characterization of the rainbow trout spleen transcriptome and identification of immune-related genes

USDA-ARS?s Scientific Manuscript database

Disease susceptibility affects production efficiency and profitability in rainbow trout aquaculture. There is limited information available regarding the functions and mechanisms of teleost immune pathways. Immunogenomics provides powerful approaches to identify disease resistance genes/gene pathway...

DIAGNOSTIC CRITERIA FOR PROLIFERATIVE THYROID LESIONS IN BONY FISHES

EPA Science Inventory

Criteria for distinguishing hyperplastic thyroid lesions from thyroid neoplasia in bony fishes have long been debated by scientists. Confusion exists because the thyroid tissue in most teleosts is unencapsulated, is occasionally found in ectopic sites, and is frequently predispos...

Zebrafish Development: High-throughput Test Systems to Assess Developmental Toxicity

EPA Science Inventory

Abstract Because of its developmental concordance, ease of handling and rapid development, the small teleost, zebrafish (Danio rerio), is frequently promoted as a vertebrate model for medium-throughput developmental screens. This present chapter discusses zebrafish as an altern...

Volatile composition of some Brazilian fruits: umbu-caja (Spondias citherea), camu-camu (Myrciaria dubia), Araça-boi (Eugenia stipitata), and Cupuaçu (Theobroma grandiflorum).

PubMed

Franco, M R; Shibamoto, T

2000-04-01

Twenty-one volatile compounds were identified for the first time by GC-MS in umbu-caja and in camu-camu, plus 30 volatile compounds were identified in araça-boi samples. Terpenic compounds predominated among the volatile compounds in these fruit samples, with the major compounds being identified as cis-beta-ocimene and caryophyllene in the northeastern fruit; alpha-pinene and d-limonene were the most abundant volatile compounds in the headspace of the Amazonian fruit camu-camu. Sesquiterpenes were the most abundant compounds in the araça-boi sample, with germacrene D presenting a higher relative percentage. The chemical class of esters predominated in the cupuaçu sample. Ethyl butyrate and hexanoate were the major compounds in the headspace of this Amazonian fruit.

Math skills and market and non-market outcomes: Evidence from an Amazonian society of forager-farmers

PubMed Central

Undurraga, Eduardo A.; Behrman, Jere R.; Grigorenko, Elena L.; Schultz, Alan; Yiu, Julie; Godoy, Ricardo A.

2013-01-01

Research in industrial nations suggests that formal math skills are associated with improvements in market and non-market outcomes. But do these associations also hold in a highly autarkic setting with a limited formal labor market? We examined this question using observational annual panel data (2008 and 2009) from 1,121 adults in a native Amazonian society of forager-farmers in Bolivia (Tsimane’). Formal math skills were associated with an increase in wealth in durable market goods and in total wealth between data collection rounds, and with improved indicators of own reported perceived stress and child health. These associations did not vary significantly by people’s Spanish skills or proximity to town. We conclude that the positive association between math skills and market and non-market outcomes extends beyond industrial nations to even highly autarkic settings. PMID:24327793

Geographic Distribution of Leishmania Species in Ecuador Based on the Cytochrome B Gene Sequence Analysis.

PubMed

Kato, Hirotomo; Gomez, Eduardo A; Martini-Robles, Luiggi; Muzzio, Jenny; Velez, Lenin; Calvopiña, Manuel; Romero-Alvarez, Daniel; Mimori, Tatsuyuki; Uezato, Hiroshi; Hashiguchi, Yoshihisa

2016-07-01

A countrywide epidemiological study was performed to elucidate the current geographic distribution of causative species of cutaneous leishmaniasis (CL) in Ecuador by using FTA card-spotted samples and smear slides as DNA sources. Putative Leishmania in 165 samples collected from patients with CL in 16 provinces of Ecuador were examined at the species level based on the cytochrome b gene sequence analysis. Of these, 125 samples were successfully identified as Leishmania (Viannia) guyanensis, L. (V.) braziliensis, L. (V.) naiffi, L. (V.) lainsoni, and L. (Leishmania) mexicana. Two dominant species, L. (V.) guyanensis and L. (V.) braziliensis, were widely distributed in Pacific coast subtropical and Amazonian tropical areas, respectively. Recently reported L. (V.) naiffi and L. (V.) lainsoni were identified in Amazonian areas, and L. (L.) mexicana was identified in an Andean highland area. Importantly, the present study demonstrated that cases of L. (V.) braziliensis infection are increasing in Pacific coast areas.

Validation of TRMM precipitation radar monthly rainfall estimates over Brazil

NASA Astrophysics Data System (ADS)

Franchito, Sergio H.; Rao, V. Brahmananda; Vasques, Ana C.; Santo, Clovis M. E.; Conforte, Jorge C.

2009-01-01

In an attempt to validate the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) over Brazil, TRMM PR estimates are compared with rain gauge station data from Agência Nacional de Energia Elétrica (ANEEL). The analysis is conducted on a seasonal basis and considers five geographic regions with different precipitation regimes. The results showed that TRMM PR seasonal rainfall is well correlated with ANEEL rainfall (correlation coefficients are significant at the 99% confidence level) over most of Brazil. The random and systematic errors of TRMM PR are sensitive to seasonal and regional differences. During December to February and March to May, TRMM PR rainfall is reliable over Brazil. In June to August (September to November) TRMM PR estimates are only reliable in the Amazonian and southern (Amazonian and southeastern) regions. In the other regions the relative RMS errors are larger than 50%, indicating that the random errors are high.

Miocene marine incursions and marine/freshwater transitions: Evidence from Neotropical fishes

NASA Astrophysics Data System (ADS)

Lovejoy, Nathan R.; Albert, James S.; Crampton, William G. R.

2006-03-01

Amazonian rivers contain a remarkable fauna of endemic species derived from taxa that generally occur in oceans and seas. Several hypotheses have been proposed to explain the origin of marine-derived lineages, including opportunistic invasions via estuaries, vicariance related to uplift of the Andes, and vicariance related to Miocene marine incursions and connections. Here, we examine available data for marine-derived lineages of four groups: stingrays (Myliobatiformes), drums (Sciaenidae), anchovies (Engraulididae), and needlefish (Belonidae). Geographic distributions, age estimates (determined using fossils, biogeography, and molecular data sets), and phylogenies for these taxa are most compatible with origination during the Miocene from marine sister groups distributed along the northern coast of South America. We speculate that unique ecological and biogeographic aspects of the Miocene upper Amazonian wetland system, most notably long-term connections with marine systems, facilitated the evolutionary transition from marine to freshwater habitats.

Dispersal assembly of rain forest tree communities across the Amazon basin

PubMed Central

Lavin, Mathew; Torke, Benjamin M.; Twyford, Alex D.; Kursar, Thomas A.; Coley, Phyllis D.; Drake, Camila; Hollands, Ruth; Pennington, R. Toby

2017-01-01

We investigate patterns of historical assembly of tree communities across Amazonia using a newly developed phylogeny for the species-rich neotropical tree genus Inga. We compare our results with those for three other ecologically important, diverse, and abundant Amazonian tree lineages, Swartzia, Protieae, and Guatteria. Our analyses using phylogenetic diversity metrics demonstrate a clear lack of geographic phylogenetic structure, and show that local communities of Inga and regional communities of all four lineages are assembled by dispersal across Amazonia. The importance of dispersal in the biogeography of Inga and other tree genera in Amazonian and Guianan rain forests suggests that speciation is not driven by vicariance, and that allopatric isolation following dispersal may be involved in the speciation process. A clear implication of these results is that over evolutionary timescales, the metacommunity for any local or regional tree community in the Amazon is the entire Amazon basin. PMID:28213498

Further blood genetic studies on Amazonian diversity--data from four Indian groups.

PubMed

Callegari-Jacques, S M; Salzano, F M; Weimer, T A; Hutz, M H; Black, F L; Santos, S E; Guerreiro, J F; Mestriner, M A; Pandey, J P

1994-01-01

Information related to 31 protein genetic systems was obtained for 307 individuals affiliated with the Cinta Larga, Karitiana, Surui and Kararaô Indians of northern Brazil. In terms of genetic distances the Cinta Larga showed more similarities with the Karitiana (both are Tupi-speaking tribes), while at a more distant level the Surui clustered with the Kararaô. The latter, a Cayapo subgroup, showed a completely different genetic constitution from the other subgroups of this same tribe. Both the Kararaô and Karitiana are small, remnant populations, and their gene pools have presumably been severely affected by random and founder effects. These results were incorporated with those of 25 other Amazonian Indian tribes, and analysis by two multivariate techniques confirmed a previously observed geographical dichotomy, suggesting either that the Amazon river constitutes a barrier to north-south gene flow or that latitudinally different past migrations entered the region from the west.

Structural factors that increase HIV/STI vulnerability among indigenous people in the Peruvian amazon.

PubMed

Orellana, E Roberto; Alva, Isaac E; Cárcamo, Cesar P; García, Patricia J

2013-09-01

We examined structural factors-social, political, economic, and environmental-that increase vulnerability to HIV among indigenous people in the Peruvian Amazon. Indigenous adults belonging to 12 different ethnic groups were purposively recruited in four Amazonian river ports and 16 indigenous villages. Qualitative data revealed a complex set of structural factors that give rise to environments of risk where health is constantly challenged. Ferryboats that cross Amazonian rivers are settings where unprotected sex-including transactional sex between passengers and boat crew and commercial sex work-often take place. Population mobility and mixing also occurs in settings like the river docks, mining sites, and other resource extraction camps, where heavy drinking and unprotected sex work are common. Multilevel, combination prevention strategies that integrate empirically based interventions with indigenous knowledge are urgently needed, not only to reduce vulnerability to HIV transmission, but also to eliminate the structural determinants of indigenous people's health.

Circadian rhythms constrain leaf and canopy gas exchange in an Amazonian forest

NASA Astrophysics Data System (ADS)

Doughty, Christopher E.; Goulden, Michael L.; Miller, Scott D.; da Rocha, Humberto R.

2006-08-01

We used a controlled-environment leaf gas-exchange system and the micrometeorological technique eddy covariance to determine whether circadian rhythms constrain the rates of leaf and canopy gas exchange in an Amazonian forest over a day. When exposed to continuous and constant light for 20 to 48 hours leaves of eleven of seventeen species reduced their photosynthetic rates and closed their stomata during the normally dark period and resumed active gas exchange during the normally light period. Similarly, the rate of whole-forest CO2 uptake at a predetermined irradiance declined during the late afternoon and early morning and increased during the middle of the day. We attribute these cycles to circadian rhythms that are analogous to ones that have been reported for herbaceous plants in the laboratory. The importance of endogenous gas exchange rhythms presents a previously unrecognized challenge for efforts to both interpret and model land-atmosphere energy and mass exchange.

Spatial patterns and fire response of recent Amazonian droughts

NASA Astrophysics Data System (ADS)

Aragão, Luiz Eduardo O. C.; Malhi, Yadvinder; Roman-Cuesta, Rosa Maria; Saatchi, Sassan; Anderson, Liana O.; Shimabukuro, Yosio Edemir

2007-04-01

There has been an increasing awareness of the possibility of climate change causing increased drought frequency in Amazonia, with ensuing impacts on ecosystems and human populations. This debate has been brought into focus by the 1997/1998 and 2005 Amazonian droughts. We analysed the spatial extent of these droughts and fire response to the 2005 drought with TRMM and NOAA-12 data, respectively. Both droughts had distinct fingerprints. The 2005 drought was characterized by its intensification throughout the dry season in south-western Amazonia. During 2005 the annual cumulative number of hot pixels in Amazonia increased 33% in relation to the 1999-2005 mean. In the Brazilian state of Acre, at the epicentre of the 2005 drought, the area of leakage forest fires was more than five times greater than the area directly deforested. Fire leakage into flammable forests may be the major agent of biome transformation in the event of increasing drought frequency.

Structural Factors That Increase HIV/STI Vulnerability Among Indigenous People in the Peruvian Amazon

PubMed Central

Orellana, E. Roberto; Alva, Isaac E.; Cárcamo, Cesar P.; García, Patricia J.

2015-01-01

We examined structural factors—social, political, economic, and environmental—that increase vulnerability to HIV among indigenous people in the Peruvian Amazon. Indigenous adults belonging to 12 different ethnic groups were purposively recruited in four Amazonian river ports and 16 indigenous villages. Qualitative data revealed a complex set of structural factors that give rise to environments of risk where health is constantly challenged. Ferryboats that cross Amazonian rivers are settings where unprotected sex—including transactional sex between passengers and boat crew and commercial sex work—often take place. Population mobility and mixing also occurs in settings like the river docks, mining sites, and other resource extraction camps, where heavy drinking and unprotected sex work are common. Multilevel, combination prevention strategies that integrate empirically based interventions with indigenous knowledge are urgently needed, not only to reduce vulnerability to HIV transmission, but also to eliminate the structural determinants of indigenous people’s health. PMID:23925407

Biogeochemistry and ecology of terrestrial ecosystems of Amazonia

NASA Astrophysics Data System (ADS)

Malhi, Yadvinder; Davidson, Eric A.

The last decade of research associated with the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) has led to substantial advances in our understanding of the biogeochemistry and ecology of Amazonian forests and savannas, in particular in relation to the carbon cycle of Amazonia. In this chapter, we present a synthesis of results and ideas that are presented in more detail in subsequent chapters, drawing together evidence from studies of forest ecology, ecophysiology, trace gas fluxes and atmospheric flux towers, large-scale rainfall manipulation experiments and soil surveys, satellite remote sensing, and quantification of carbon and nutrient stocks and flows. The studies have demonstrated the variability of the functioning and biogeochemistry of Amazonian forests at a range of spatial and temporal scales, and they provide clues as to how Amazonia will respond to ongoing direct pressure and global atmospheric change. We conclude by highlighting key questions for the next decade of research to address.

Tool use by Amazonian capuchin monkeys during predation on caiman nests in a high-productivity forest.

PubMed

Torralvo, Kelly; Rabelo, Rafael M; Andrade, Alfredo; Botero-Arias, Robinson

2017-04-01

Descriptions of new tool-use events are important for understanding how ecological context may drive the evolution of tool use among primate traditions. Here, we report a possible case of the first record of tool use by wild Amazonian capuchin monkeys (Sapajus macrocephalus). The record was made by a camera trap, while we were monitoring caiman nest predation at Mamirauá Reserve in Central Amazonia. An adult individual was registered in a bipedal posture, apparently using a branch as a shovel to dig eggs out of a nest. Caiman eggs are frequently depredated by opportunistic animals, such as the capuchin monkeys. As the Mamirauá Reserve is covered by a high-productivity forest, and caiman eggs are a high-quality food resource seasonally available on the ground, we believe that tool use by capuchins is more likely to be opportunity driven, rather than necessity driven, in our study site.

Securitization, alterity, and the state Human (in)security on an Amazonian frontier

PubMed Central

Brightman, Marc; Grotti, Vanessa

2016-01-01

Focusing on the region surrounding the Maroni River, which forms the border between Suriname and French Guiana, we examine how relations between different state and non-state social groups are articulated in terms of security. The region is characterised by multiple “borders” and frontiers of various kinds, the state boundary having the features of an interface or contact zone. Several key collectivities meet in this border zone: native Amazonians, tribal Maroon peoples, migrant Brazilian gold prospectors, and metropolitan French state functionaries. We explore the relationships between these different sets of actors and describe how their mutual encounters center on discourses of human and state security, thus challenging the commonly held view of the region as a stateless zone and showing that the “human security” of citizens from the perspective of the state may compete with locally salient ideas or experiences of well-being. PMID:27996063

Methane flux from the Central Amazonian Floodplain

NASA Technical Reports Server (NTRS)

Bartlett, Karen B.; Crill, Patrick M.; Sebacher, Daniel I.; Harriss, Robert C.; Wilson, John O.; Melack, John M.

1987-01-01

A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49% of the flux from open water, 54% of that from flooded forests, and 64% of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12% of the estimated global natural sources of methane.

Dispersal assembly of rain forest tree communities across the Amazon basin.

PubMed

Dexter, Kyle G; Lavin, Mathew; Torke, Benjamin M; Twyford, Alex D; Kursar, Thomas A; Coley, Phyllis D; Drake, Camila; Hollands, Ruth; Pennington, R Toby

2017-03-07

We investigate patterns of historical assembly of tree communities across Amazonia using a newly developed phylogeny for the species-rich neotropical tree genus Inga We compare our results with those for three other ecologically important, diverse, and abundant Amazonian tree lineages, Swartzia , Protieae, and Guatteria Our analyses using phylogenetic diversity metrics demonstrate a clear lack of geographic phylogenetic structure, and show that local communities of Inga and regional communities of all four lineages are assembled by dispersal across Amazonia. The importance of dispersal in the biogeography of Inga and other tree genera in Amazonian and Guianan rain forests suggests that speciation is not driven by vicariance, and that allopatric isolation following dispersal may be involved in the speciation process. A clear implication of these results is that over evolutionary timescales, the metacommunity for any local or regional tree community in the Amazon is the entire Amazon basin.

Ecological Suitability and Spatial Distribution of Five Anopheles Species in Amazonian Brazil

PubMed Central

McKeon, Sascha N.; Schlichting, Carl D.; Povoa, Marinete M.; Conn, Jan E.

2013-01-01

Seventy-six sites characterized in Amazonian Brazil revealed distinct habitat diversification by examining the environmental factors associated with the distribution and abundance of five anopheline species (Diptera: Culicidae) in the subgenus Nyssorhynchus. These included three members of the Albitarsis Complex, Anopheles oryzalimnetes, Anopheles marajoara, Anopheles janconnae; Anopheles triannulatus, and Anopheles goeldii. Anopheles janconnae abundance had a positive correlation to water flow and a negative relationship to sun exposure. Abundance of An. oryzalimentes was associated with water chemistry. Anopheles goeldii larvae were abundant in shaded, more saline waters. Anopheles marajoara and An. triannulatus were negatively associated with available resources, although An. marajoara also showed several local correlations. These analyses suggest An. triannulatus is a habitat generalist, An. oryzalimentes and An. janconnae are specialists, and An. marajoara and An. goeldii could not be easily classified either way. Correlations described herein provide testable hypotheses for future research and identifying habitats for vector control. PMID:23546804

Airborne observations reveal elevational gradient in tropical forest isoprene emissions.

PubMed

Gu, Dasa; Guenther, Alex B; Shilling, John E; Yu, Haofei; Huang, Maoyi; Zhao, Chun; Yang, Qing; Martin, Scot T; Artaxo, Paulo; Kim, Saewung; Seco, Roger; Stavrakou, Trissevgeni; Longo, Karla M; Tóta, Julio; de Souza, Rodrigo Augusto Ferreira; Vega, Oscar; Liu, Ying; Shrivastava, Manish; Alves, Eliane G; Santos, Fernando C; Leng, Guoyong; Hu, Zhiyuan

2017-05-23

Isoprene dominates global non-methane volatile organic compound emissions, and impacts tropospheric chemistry by influencing oxidants and aerosols. Isoprene emission rates vary over several orders of magnitude for different plants, and characterizing this immense biological chemodiversity is a challenge for estimating isoprene emission from tropical forests. Here we present the isoprene emission estimates from aircraft eddy covariance measurements over the Amazonian forest. We report isoprene emission rates that are three times higher than satellite top-down estimates and 35% higher than model predictions. The results reveal strong correlations between observed isoprene emission rates and terrain elevations, which are confirmed by similar correlations between satellite-derived isoprene emissions and terrain elevations. We propose that the elevational gradient in the Amazonian forest isoprene emission capacity is determined by plant species distributions and can substantially explain isoprene emission variability in tropical forests, and use a model to demonstrate the resulting impacts on regional air quality.

A study of the hydrothermal alteration in Paleoproterozoic volcanic centers, São Félix do Xingu region, Amazonian Craton, Brazil, using short-wave infrared spectroscopy

NASA Astrophysics Data System (ADS)

da Cruz, Raquel Souza; Fernandes, Carlos Marcello Dias; Villas, Raimundo Netuno Nobre; Juliani, Caetano; Monteiro, Lena Virgínia Soares; de Almeida, Teodoro Isnard Ribeiro; Lagler, Bruno; de Carvalho Carneiro, Cleyton; Misas, Carlos Mario Echeverri

2015-10-01

Hypogene hydrothermal minerals have been identified by short-wave infrared spectroscopy in hydrothermally altered rocks from the Sobreiro and Santa Rosa formations, which belong to a Paleoproterozoic volcano-plutonic system in Amazonian craton. Three clay minerals are spectrally recognized: montmorillonite, kaolinite, and illite. The integration of these data with those available in the literature, including gold occurrences, suggests that those rocks are hydrothermal products of both volcanic thermal sources and later crustal intrusions, as evidenced by variable styles of propylitic, sericitic, potassic, and intermediate argillic alteration. The influence of meteoric fluids is emphasized. This low cost exploratory technique, which can be applied to hand samples, seems to be promising in the separation of hydrothermally altered volcano-plutonic centers in regions submitted to severe weathering conditions, in addition to aid elaborating models for prospecting mineral deposits.

New records of Amblyomma goeldii (Acari: Ixodidae) and description of the nymphal stage.

PubMed

Martins, Thiago F; Gianizella, Sérgio L; Nunes, Pablo H; Faria, Diogo C L O; Do Nascimento, Carlos A R; Abrahão, Carlos R; Miranda, Flávia R; Teixeira, Rodrigo H F; Ramirez, Diego G; Barros-Battesti, Darci M; Labruna, Marcelo B

2015-04-29

Since its original description from the Amazonian region, the tick species Amblyomma goeldii Neumann, 1899 has been misidentified with Amblyomma rotundatum Koch, 1844 in different countries of the Neotropical region. Because of this, some authors have considered that the only confirmed records of A. goeldii were from French Guyana. Herein, we reviewed all specimens of A. goeldii that have been deposited at two tick collections in Brazil. In addition, we describe the nymphal stage of A. goeldii for the first time. A total of 10 unpublished records of the adult stage of A. goeldii are recorded from the Amazonian region of Brazil, confirming the occurrence of A. goeldii in this country. Except for one record on the snake Boa constrictor Linnaeus, all records of A. goeldii reported in the present study were from anteaters (Pilosa: Myrmecophagidae). Our results, in conjunction with previous literature records, indicate that anteaters and large snakes are important hosts for the adult stage of A. goeldii. The nymph of A. goeldii is morphologically similar to the nymphs of Amblyomma romitii Tonelli-Rondelli, 1939, Amblyomma dissimile Koch, 1844, and A. rotundatum. We present a modification of a previously published taxonomic key of Amblyomma nymphs from Brazil, in order to perform taxonomic identification of the nymph of A. goeldii based on external morphology. The geographical distribution of A. goeldii appears to be restricted to the Amazonian region. There were no previous host records for the immature stages of A. goeldii, thus it is expected that the present nymphal description will facilitate further works on the ecology of this poorly studied tick species.

Deforestation and stream warming affect body size of Amazonian fishes.

PubMed

Ilha, Paulo; Schiesari, Luis; Yanagawa, Fernando I; Jankowski, KathiJo; Navas, Carlos A

2018-01-01

Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43-55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin.

Drought responses of flood-tolerant trees in Amazonian floodplains

PubMed Central

Parolin, Pia; Lucas, Christine; Piedade, Maria Teresa F.; Wittmann, Florian

2010-01-01

Background Flood-tolerant tree species of the Amazonian floodplain forests are subjected to an annual dry period of variable severity imposed when low river-water levels coincide with minimal precipitation. Although the responses of these species to flooding have been examined extensively, their responses to drought, in terms of phenology, growth and physiology, have been neglected hitherto, although some information is found in publications that focus on flooding. Scope The present review examines the dry phase of the annual flooding cycle. It consolidates existing knowledge regarding responses to drought among adult trees and seedlings of many Amazonian floodplain species. Main Findings Flood-tolerant species display variable physiological responses to dry periods and drought that indicate desiccation avoidance, such as reduced photosynthetic activity and reduced root respiration. However, tolerance and avoidance strategies for drought vary markedly among species. Drought can substantially decrease growth, biomass and photosynthetic activity among seedlings in field and laboratory studies. When compared with the responses to flooding, drought can impose higher seedling mortality and slower growth rates, especially among evergreen species. Results indicate that tolerance and avoidance strategies for drought vary markedly between species. Both seedling recruitment and photosynthetic activity are affected by drought, Conclusions For many species, the effects of drought can be as important as flooding for survival and growth, particularly at the seedling phase of establishment, ultimately influencing species composition. In the context of climate change and predicted decreases in precipitation in the Amazon Basin, the effects of drought on plant physiology and species distribution in tropical floodplain forest ecosystems should not be overlooked. PMID:19880423

Exploring the mitochondrial DNA variability of the Amazonian Yanomami.

PubMed

Varano, Sara; Scorrano, Gabriele; Martínez-Labarga, Cristina; Finocchio, Andrea; Rapone, Cesare; Berti, Andrea; Rickards, Olga

2016-11-01

The aim of this study was to explore the mitochondrial variability in the Yanomami population to reconstruct its demographic history and explore its genetic composition in relation to its cultural and linguistic features. A total of 174 human head hair shafts -collected in 1958- belonging to individuals from a Yanomami group living in Santa Isabel, Brazil, were analyzed. Automated extraction of the hairs was performed, and several methods were applied to optimize the analysis of the degraded DNA. The mtDNA hypervariable segments I-II, along with the 9-bp COII-tRNA Lys deletion, were investigated. Using published data from the Yanomami and other Amazonian populations, several statistical analyses were carried out to explore the genetic variability within the study population. Ninety eight percent of the mitochondrial DNA (mtDNA) sequences analyzed belonged to Native American haplogroups, while 2% belonged to African haplogroups. Compared with the Yanomami groups previously studied, the Santa Isabel sample seemed more genetically similar to other Amazonian populations. Among the Yanomami samples studied to date, the Santa Isabel Yanomami show a higher genetic heterogeneity. This could be due to gene flow with non-Yanomami populations, as well as to the introduction of new mitochondrial haplotypes by gold miners. In both cases, the geographic location of Santa Isabel might have made this Yanomami village less isolated than the others, suggesting that the Rio Negro played a central role in increasing its genetic variability. On the whole, the Yanomami were quite genetically diversified, probably mirroring their great linguistic heterogeneity. Am. J. Hum. Biol. 28:846-856, 2016. © 2016Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Insight into the Wild Origin, Migration and Domestication History of the Fine Flavour Nacional Theobroma cacao L. Variety from Ecuador

PubMed Central

Loor Solorzano, Rey Gaston; Fouet, Olivier; Lemainque, Arnaud; Pavek, Sylvana; Boccara, Michel; Argout, Xavier; Amores, Freddy; Courtois, Brigitte; Risterucci, Ange Marie; Lanaud, Claire

2012-01-01

Ecuador’s economic history has been closely linked to Theobroma cacao L cultivation, and specifically to the native fine flavour Nacional cocoa variety. The original Nacional cocoa trees are presently in danger of extinction due to foreign germplasm introductions. In a previous work, a few non-introgressed Nacional types were identified as potential founders of the modern Ecuadorian cocoa population, but so far their origin could not be formally identified. In order to determine the putative centre of origin of Nacional and trace its domestication history, we used 80 simple sequence repeat (SSR) markers to analyse the relationships between these potential Nacional founders and 169 wild and cultivated cocoa accessions from South and Central America. The highest genetic similarity was observed between the Nacional pool and some wild genotypes from the southern Amazonian region of Ecuador, sampled along the Yacuambi, Nangaritza and Zamora rivers in Zamora Chinchipe province. This result was confirmed by a parentage analysis. Based on our results and on data about pre-Columbian civilization and Spanish colonization history of Ecuador, we determined, for the first time, the possible centre of origin and migration events of the Nacional variety from the Amazonian area until its arrival in the coastal provinces. As large unexplored forest areas still exist in the southern part of the Ecuadorian Amazonian region, our findings could provide clues as to where precious new genetic resources could be collected, and subsequently used to improve the flavour and disease resistance of modern Ecuadorian cocoa varieties. PMID:23144883

Discovering Hidden Diversity of Characins (Teleostei: Characiformes) in Ecuador’s Yasuní National Park

PubMed Central

Escobar-Camacho, Daniel; Barriga, Ramiro; Ron, Santiago R.

2015-01-01

Background Management and conservation of biodiversity requires adequate species inventories. The Yasuní National Park is one of the most diverse regions on Earth and recent studies of terrestrial vertebrates, based on genetic evidence, have shown high levels of cryptic and undescribed diversity. Few genetic studies have been carried out in freshwater fishes from western Amazonia. Thus, in contrast with terrestrial vertebrates, their content of cryptic diversity remains unknown. In this study, we carried out genetic and morphological analyses on characin fishes at Yasuní National Park, in eastern Ecuador. Our goal was to identify cryptic diversity among one of the most speciose fish families in the Amazon region. This is the first time that genetic evidence has been used to assess the species content of the Napo Basin, one of the richest regions in vertebrate diversity. Results Phylogenetic analyses of partial mitochondrial 16S ribosomal RNA gene (∼600 pb) DNA sequences from 232 specimens of the family Characidae and its closest groups revealed eight candidate new species among 33 species sampled, representing a 24% increase in species number. Analyses of external morphology allowed us to confirm the species status of six of the candidate species. Conclusions Our results show high levels of cryptic diversity in Amazonian characins. If this group is representative of other Amazonian fish, our results would imply that the species richness of the Amazonian ichthyofauna is highly underestimated. Molecular methods are a necessary tool to obtain more realistic inventories of Neotropical freshwater fishes. PMID:26275041

Development of a biocompatible magnetic nanofluid by incorporating SPIONs in Amazonian oils

NASA Astrophysics Data System (ADS)

Gaspar, André S.; Wagner, Friedrich E.; Amaral, Vítor S.; Costa Lima, Sofia A.; Khomchenko, Vladimir A.; Santos, Judes G.; Costa, Benilde F. O.; Durães, Luísa

2017-02-01

Higher quality magnetic nanoparticles are needed for use as magnetic nanoprobe in medical imaging techniques and cancer therapy. Moreover, the phytochemistry benefits of some Amazonian essential oils have sparked great interest for medical treatments. In this work, a magnetic nanoprobe was developed, allying the biocompatibility and superparamagnetism of iron oxide nanoparticles (SPIONs) with benefits associated with Amazonian oils from Copaiba and Andiroba trees. SPIONs were obtained by two thermal decomposition procedures and different amounts of precursors (iron acetylacetonates). Their characterization was accomplished by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy and magnetization. The obtained nanoparticles composition and magnetic properties were not affected by the relative proportion of iron(II) and iron(III) in the precursor system. However, when changing the reducing and stabilizing agents the coating layer shows different compositions/relative weight - the more promising SPIONs have a coating mainly composed by oleylamine and an iron oxide:coating wt% ratio of 55:45. Nanoparticles size distributions were very narrow and centred in the average size of 6-7 nm. Cellular assays confirmed the biocompatibility of SPIONs and their effective internalization in human colon cancer cells. Mössbauer/XRD results indicated maghemite as their main iron oxide phase, but traces of magnetite proved to be present. Magnetization saturations of 57 emu/g at 5 K and 42 emu/g at 300 K were achieved. With incorporation of SPIONs into Copaiba and Andiroba essential oils, these values show a 4-fold decrease, but the supermagnetic behaviour is preserved providing the effective formation of a nanofluid.

Apolipoprotein E4 is associated with improved cognitive function in Amazonian forager-horticulturalists with a high parasite burden

PubMed Central

Trumble, Benjamin C.; Stieglitz, Jonathan; Blackwell, Aaron D.; Allayee, Hooman; Beheim, Bret; Finch, Caleb E.; Gurven, Michael; Kaplan, Hillard

2017-01-01

The apolipoprotein E4 (E4) allele is present worldwide, despite its associations with higher risk of cardiovascular morbidity, accelerated cognitive decline during aging, and Alzheimer’s disease (AD). The E4 allele is especially prevalent in some tropical regions with a high parasite burden. Equatorial populations also face a potential dual burden of high E4 prevalence combined with parasitic infections that can also reduce cognitive performance. We examined the interactions of E4, parasite burden, and cognitive performance in a traditional, nonindustrialized population of Amazonian forager-horticulturalists (N = 372) to test whether E4 protects against cognitive decline in environments with a heavy pathogen burden. Contrary to observations in industrial populations, older adult E4 carriers with high parasite burdens either maintained or showed slight improvements in cognitive performance, whereas non-E4 carriers with a high parasite burden showed reduced cognitive performance. Being an E4 carrier is the strongest risk factor to date of AD and cognitive decline in industrial populations; it is associated with greater cognitive performance in individuals facing a high parasite and pathogen load, suggesting advantages to the E4 allele under certain environmental conditions. The current mismatch between postindustrial hygienic lifestyles and active parasite-rich environs may be critical for understanding genetic risk for cognitive aging.—Trumble, B. C., Stieglitz, J., Blackwell, A. D., Allayee, H., Beheim, B., Finch, C. E., Gurven, M., Kaplan, H. Apolipoprotein E4 is associated with improved cognitive function in Amazonian forager-horticulturalists with a high parasite burden. PMID:28031319

Deforestation and stream warming affect body size of Amazonian fishes

PubMed Central

Yanagawa, Fernando I.; Jankowski, KathiJo; Navas, Carlos A.

2018-01-01

Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43–55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin. PMID:29718960

Step selection techniques uncover the environmental predictors of space use patterns in flocks of Amazonian birds.

PubMed

Potts, Jonathan R; Mokross, Karl; Stouffer, Philip C; Lewis, Mark A

2014-12-01

Understanding the behavioral decisions behind animal movement and space use patterns is a key challenge for behavioral ecology. Tools to quantify these patterns from movement and animal-habitat interactions are vital for transforming ecology into a predictive science. This is particularly important in environments undergoing rapid anthropogenic changes, such as the Amazon rainforest, where animals face novel landscapes. Insectivorous bird flocks are key elements of avian biodiversity in the Amazonian ecosystem. Therefore, disentangling and quantifying the drivers behind their movement and space use patterns is of great importance for Amazonian conservation. We use a step selection function (SSF) approach to uncover environmental drivers behind movement choices. This is used to construct a mechanistic model, from which we derive predicted utilization distributions (home ranges) of flocks. We show that movement decisions are significantly influenced by canopy height and topography, but depletion and renewal of resources do not appear to affect movement significantly. We quantify the magnitude of these effects and demonstrate that they are helpful for understanding various heterogeneous aspects of space use. We compare our results to recent analytic derivations of space use, demonstrating that the analytic approximation is only accurate when assuming that there is no persistence in the animals' movement. Our model can be translated into other environments or hypothetical scenarios, such as those given by proposed future anthropogenic actions, to make predictions of spatial patterns in bird flocks. Furthermore, our approach is quite general, so could potentially be used to understand the drivers of movement and spatial patterns for a wide variety of animal communities.

Insight into the wild origin, migration and domestication history of the fine flavour Nacional Theobroma cacao L. variety from Ecuador.

PubMed

Loor Solorzano, Rey Gaston; Fouet, Olivier; Lemainque, Arnaud; Pavek, Sylvana; Boccara, Michel; Argout, Xavier; Amores, Freddy; Courtois, Brigitte; Risterucci, Ange Marie; Lanaud, Claire

2012-01-01

Ecuador's economic history has been closely linked to Theobroma cacao L cultivation, and specifically to the native fine flavour Nacional cocoa variety. The original Nacional cocoa trees are presently in danger of extinction due to foreign germplasm introductions. In a previous work, a few non-introgressed Nacional types were identified as potential founders of the modern Ecuadorian cocoa population, but so far their origin could not be formally identified. In order to determine the putative centre of origin of Nacional and trace its domestication history, we used 80 simple sequence repeat (SSR) markers to analyse the relationships between these potential Nacional founders and 169 wild and cultivated cocoa accessions from South and Central America. The highest genetic similarity was observed between the Nacional pool and some wild genotypes from the southern Amazonian region of Ecuador, sampled along the Yacuambi, Nangaritza and Zamora rivers in Zamora Chinchipe province. This result was confirmed by a parentage analysis. Based on our results and on data about pre-Columbian civilization and Spanish colonization history of Ecuador, we determined, for the first time, the possible centre of origin and migration events of the Nacional variety from the Amazonian area until its arrival in the coastal provinces. As large unexplored forest areas still exist in the southern part of the Ecuadorian Amazonian region, our findings could provide clues as to where precious new genetic resources could be collected, and subsequently used to improve the flavour and disease resistance of modern Ecuadorian cocoa varieties.

Apolipoprotein E4 is associated with improved cognitive function in Amazonian forager-horticulturalists with a high parasite burden.

PubMed

Trumble, Benjamin C; Stieglitz, Jonathan; Blackwell, Aaron D; Allayee, Hooman; Beheim, Bret; Finch, Caleb E; Gurven, Michael; Kaplan, Hillard

2017-04-01

The apolipoprotein E4 (E4) allele is present worldwide, despite its associations with higher risk of cardiovascular morbidity, accelerated cognitive decline during aging, and Alzheimer 's disease (AD). The E4 allele is especially prevalent in some tropical regions with a high parasite burden. Equatorial populations also face a potential dual burden of high E4 prevalence combined with parasitic infections that can also reduce cognitive performance. We examined the interactions of E4, parasite burden, and cognitive performance in a traditional, nonindustrialized population of Amazonian forager-horticulturalists ( N = 372) to test whether E4 protects against cognitive decline in environments with a heavy pathogen burden. Contrary to observations in industrial populations, older adult E4 carriers with high parasite burdens either maintained or showed slight improvements in cognitive performance, whereas non-E4 carriers with a high parasite burden showed reduced cognitive performance. Being an E4 carrier is the strongest risk factor to date of AD and cognitive decline in industrial populations; it is associated with greater cognitive performance in individuals facing a high parasite and pathogen load, suggesting advantages to the E4 allele under certain environmental conditions. The current mismatch between postindustrial hygienic lifestyles and active parasite-rich environs may be critical for understanding genetic risk for cognitive aging.-Trumble, B. C., Stieglitz, J., Blackwell, A. D., Allayee, H., Beheim, B., Finch, C. E., Gurven, M., Kaplan, H. Apolipoprotein E4 is associated with improved cognitive function in Amazonian forager-horticulturalists with a high parasite burden. © FASEB.

Tiger-Moths in Savannas in Eastern Amazon: First Assessment of Diversity and Seasonal Aspects.

PubMed

Valente, D M P; Zenker, M M; Teston, J A

2018-01-06

Biodiversity knowledge on insects is urgently needed due to the ever growing demand for food and the consequent deforestation process and loss of natural habitats in many understudied tropical regions. In this paper, we describe the outcome of a biodiversity research on tiger moths performed for the first time in a poorly studied Amazonian landscape-the savanna. We sampled tiger moths monthly with UV automatic light traps for 12 consecutive months in two sampling points in an area of savanna in eastern Amazon, and we compared our results to previously available data for eastern Amazon. We found a total of 91 species of which 80 were identified to species level. The most species-rich subtribes were Phaegopterina and Euchromiina with 32 species each. Species richness and abundance did not differ among sampling sites, but in general the species richness was higher during the dry season while abundance was higher during the wet season. This seasonal diversity pattern differs from the most common patterns recorded for savannas in other parts of the world. The species composition also changed in wet and dry seasons and correlated significantly with temperature and relative humidity. Our results suggest that the alpha diversity of the Amazonian savannas in our sampling area is lower than that in nearby rain forests and similar to that in agriculturally disturbed areas surrounded by rain forests. However, the species composition differed considerably from natural and disturbed areas. These results highlight the need of basic biodiversity surveys of insects in Amazonian savannas.

Step selection techniques uncover the environmental predictors of space use patterns in flocks of Amazonian birds

PubMed Central

Potts, Jonathan R; Mokross, Karl; Stouffer, Philip C; Lewis, Mark A

2014-01-01

Understanding the behavioral decisions behind animal movement and space use patterns is a key challenge for behavioral ecology. Tools to quantify these patterns from movement and animal–habitat interactions are vital for transforming ecology into a predictive science. This is particularly important in environments undergoing rapid anthropogenic changes, such as the Amazon rainforest, where animals face novel landscapes. Insectivorous bird flocks are key elements of avian biodiversity in the Amazonian ecosystem. Therefore, disentangling and quantifying the drivers behind their movement and space use patterns is of great importance for Amazonian conservation. We use a step selection function (SSF) approach to uncover environmental drivers behind movement choices. This is used to construct a mechanistic model, from which we derive predicted utilization distributions (home ranges) of flocks. We show that movement decisions are significantly influenced by canopy height and topography, but depletion and renewal of resources do not appear to affect movement significantly. We quantify the magnitude of these effects and demonstrate that they are helpful for understanding various heterogeneous aspects of space use. We compare our results to recent analytic derivations of space use, demonstrating that the analytic approximation is only accurate when assuming that there is no persistence in the animals' movement. Our model can be translated into other environments or hypothetical scenarios, such as those given by proposed future anthropogenic actions, to make predictions of spatial patterns in bird flocks. Furthermore, our approach is quite general, so could potentially be used to understand the drivers of movement and spatial patterns for a wide variety of animal communities. PMID:25558353

Comparative genomics of ParaHox clusters of teleost fishes: gene cluster breakup and the retention of gene sets following whole genome duplications

PubMed Central

Siegel, Nicol; Hoegg, Simone; Salzburger, Walter; Braasch, Ingo; Meyer, Axel

2007-01-01

Background The evolutionary lineage leading to the teleost fish underwent a whole genome duplication termed FSGD or 3R in addition to two prior genome duplications that took place earlier during vertebrate evolution (termed 1R and 2R). Resulting from the FSGD, additional copies of genes are present in fish, compared to tetrapods whose lineage did not experience the 3R genome duplication. Interestingly, we find that ParaHox genes do not differ in number in extant teleost fishes despite their additional genome duplication from the genomic situation in mammals, but they are distributed over twice as many paralogous regions in fish genomes. Results We determined the DNA sequence of the entire ParaHox C1 paralogon in the East African cichlid fish Astatotilapia burtoni, and compared it to orthologous regions in other vertebrate genomes as well as to the paralogous vertebrate ParaHox D paralogons. Evolutionary relationships among genes from these four chromosomal regions were studied with several phylogenetic algorithms. We provide evidence that the genes of the ParaHox C paralogous cluster are duplicated in teleosts, just as it had been shown previously for the D paralogon genes. Overall, however, synteny and cluster integrity seems to be less conserved in ParaHox gene clusters than in Hox gene clusters. Comparative analyses of non-coding sequences uncovered conserved, possibly co-regulatory elements, which are likely to contain promoter motives of the genes belonging to the ParaHox paralogons. Conclusion There seems to be strong stabilizing selection for gene order as well as gene orientation in the ParaHox C paralogon, since with a few exceptions, only the lengths of the introns and intergenic regions differ between the distantly related species examined. The high degree of evolutionary conservation of this gene cluster's architecture in particular – but possibly clusters of genes more generally – might be linked to the presence of promoter, enhancer or inhibitor motifs that serve to regulate more than just one gene. Therefore, deletions, inversions or relocations of individual genes could destroy the regulation of the clustered genes in this region. The existence of such a regulation network might explain the evolutionary conservation of gene order and orientation over the course of hundreds of millions of years of vertebrate evolution. Another possible explanation for the highly conserved gene order might be the existence of a regulator not located immediately next to its corresponding gene but further away since a relocation or inversion would possibly interrupt this interaction. Different ParaHox clusters were found to have experienced differential gene loss in teleosts. Yet the complete set of these homeobox genes was maintained, albeit distributed over almost twice the number of chromosomes. Selection due to dosage effects and/or stoichiometric disturbance might act more strongly to maintain a modal number of homeobox genes (and possibly transcription factors more generally) per genome, yet permit the accumulation of other (non regulatory) genes associated with these homeobox gene clusters. PMID:17822543

ENVIRONMENTAL CARCINOGENESIS IN THE MUMMICHOG, FUNDULUS HETEROCLITUS: FIELD AND LABORATORY INVESTIGATIONS

EPA Science Inventory

The mummichog, Fundulus heteroclitus, is a small estuarine teleost inhabiting coastal embayments along much of the eastern seaboard of the US. We have been investigating an association between chemical contaminant exposure and adverse health impacts in this small cyprinodontid fi...

Misalignment of Lava Flows from Topographic Slope Directions Reveals Late Amazonian Deformation at Arsia Mons, Mars

NASA Astrophysics Data System (ADS)

Waring, B. A.; Chadwick, J.; McGovern, P. J., Jr.; Tucker, W.

2017-12-01

Arsia Mons is the southernmost of the three large Tharsis Montes near the equator of Mars and one of the largest volcanoes in the solar system. The main edifice of Arsia is about 440 km in diameter, the summit is over 9 km above the surrounding plains and has a pronounced 110 km caldera. Like the other Tharsis volcanoes, Arsia has a large, Late Amazonian glacial deposit on its NW flank. Previous crater retention studies for lava flows on Arsia have shown that the volcano experienced significant volcanic activity in the past 200 Ma. In this study, numerous long (>25 km), thin lava flows on the plains surrounding Arsia were mapped and used as indicators of the topographic slope direction at the time of their emplacement. The azimuthal orientation of each flow was compared with the present-day slope directions on the surrounding plains, derived from Mars Orbiter Laser Altimeter (MOLA) topographic data. The results reveal regions around Arsia where the flows no longer conform to the topography, indicating deformation in the time since the flows where emplaced. In a region of Daedalia Planum to the SE of Arsia, modern slope directions adjacent to 40 long lava flows are consistently misaligned from the paleo-slopes indicated by the lava flow orientations, with an angular offset that averages 7.2° in the clockwise direction. Crater size-frequency measurements for these tilted plains using CraterStats software indicate that the deformation responsible for the misaligned flows took place since 330 ± 10 Ma. Conversely, part of Daedalia Planum to the southwest of Arsia is younger, with a crater retention age of 160 ± 6 Ma, and this area shows no consistent flow-topography misalignments. These observations suggest that extensive regional deformation occurred between the two dates, consistent with other evidence for significant volcanism at Arsia in the Late Amazonian at about 200 Ma. Geophysical modelling using the finite element program COMSOL Multiphysics is planned to characterize the source and magnitude of the observed deformation. Similar methods were successfully used in a previous study to identify and measure subsidence of Olympus Mons. The goal of the study is to refine the timing of the contemporaneous Late Amazonian volcanic, tectonic, and glacial events on Arsia Mons and to understand their relationships.

Brazil's Amazonian dams: Ecological and socioeconomic impacts

NASA Astrophysics Data System (ADS)

Fearnside, P. M.

2016-12-01

Brazil's 2015-2024 Energy Expansion Plan calls for 11 hydroelectric dams with installed capacity ≥ 30 MW in the country's Amazon region. Dozens of other large dams are planned beyond this time horizon, and dams with < 30 MW installed capacity number in the hundreds. Amazonian dams have substantial environmental and socioeconomic impacts. Loss of forest to flooding is one, the Balbina and Tucuruí Dams being examples (each 3000 km2). If the Babaquara/Altamira Dam is built it will flood as much forest as both of these combined. Some planned dams imply loss of forest in protected areas, for example on the Tapajós River. Aquatic and riparian ecosystems are lost, including unique biodiversity. Endemic fish species in rapids on the Xingu and Tapajós Rivers are examples. Fish migrations are blocked, such as the commercially important "giant catfish" of the Madeira River. Dams emit greenhouse gases, including CO2 from the trees killed and CH4 from decay under anoxic conditions at the bottom of reservoirs. Emissions can exceed those from fossil-fuel generation, particularly over the 20-year period during which global emissions must be greatly reduced to meet 1.5-2°C limit agreed in Paris. Carbon credit for dams under the Climate Convention causes further net emission because the dams are not truly "additional." Anoxic environments in stratified reservoirs cause methylation of mercury present in Amazonian soils, which concentrates in fish, posing a health risk to human consumers. Population displacement is a major impact; for example, the Marabá Dam would displace 40,000 people, mostly traditional riverside dwellers (ribeirinhos). Various dams impact indigenous peoples, such as the Xingu River dams (beginning with Belo Monte) and the São Luiz do Tapajós and Chacorão Dams on the Tapajós River. Brazil has many energy options other than dams. Much energy use has little benefit for the country, such as exporting aluminum. Electric showerheads use 5% of the country's power. Losses in transmission lines (20%) are far above global averages and can be expected to increase as Amazonian hydroelectric dams far from consumer centers come on line. Brazil has tremendous wind and solar potential, but these do not have the same priority as dams. At the root of many questionable policies is a decision-making process in need of reform.

Sedimentology and hydrology of a well-preserved paleoriver systems with a series of dam-breach paleolakes at Moa Valles, Mars

NASA Astrophysics Data System (ADS)

Salese, Francesco; Di Achille, Gaetano; Neesemann, Adrian; Ori, Gian Gabriele; Hauber, Ernst

2016-04-01

Moa Valles is a well-preserved paleodrainage system that is nearly 300-km-long and carved into ancient highland terrains west of Idaeus Fossae. The paleofluvial system apparently originated from fluidized ejecta blankets, and it consists of a series of dam-breach paleolakes with associated fan-shaped sedimentary deposits. This paleofluvial system shows a rich morphological record of hydrologic activity in the highlands of Mars. Based on crater counting the latter activity seems to be Amazonian in age (2.43 - 1.41 Ga). This work is based on a digital elevation model (DEM) derived from Context camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) stereo images. Our goals are to (a) study the complex channel flow paths draining into Idaeus Fossae after forming a series of dam-breach paleolakes and to (b) investigate the origin and evolution of this valley system with its implications for climate and tectonic control. The first part of the system is characterized by many paleolakes, which are interconnected and drain eastward into Liberta crater, forming a complex and multilobate deltaic deposit exhibiting a well-developed channelized distributary pattern with evidence of switching on the delta plain. A breach area, consisting of three spillover channels, is present in the eastern part of the crater rim. These channels connect the Liberta crater to the eastward portion of the valley system, continuing toward Moa Valles with a complex pattern of anabranching channels that is more than 180-km-long. Our crater counting results and hydrological calculations of infilling and spillover discharges of the Liberta crater-lake suggest that the system is the result of an Early Amazonian water-rich environment that was likely sustained by relatively short fluvial events (<102 years), thereby supporting the hypotheses that water-related erosion might have been active on Mars (at least locally) during the Amazonian. The most important water source for the system could have been shallow ice melting triggered by impact craters. Indeed, the stratigraphic relationships between channels and crater ejecta show very clearly that the channels cut through the ejecta thus postdating them. The occurrence of relatively recent (likely Amazonian) hydrological activity supports the hypothesis that hydrological activity could have been possible, at least locally, after the Noachian-Hesperian boundary.

Drying method has no substantial effect on δ(15)N or δ(13)C values of muscle tissue from teleost fishes.

PubMed

Bessey, Cindy; Vanderklift, Mathew A

2014-02-15

Stable isotope analysis (SIA) is a powerful tool in many fields of research that enables quantitative comparisons among studies, if similar methods have been used. The goal of this study was to determine if three different drying methods commonly used to prepare samples for SIA yielded different δ(15)N and δ(13)C values. Muscle subsamples from 10 individuals each of three teleost species were dried using three methods: (i) oven, (ii) food dehydrator, and (iii) freeze-dryer. All subsamples were analysed for δ(15)N and δ(13)C values, and nitrogen and carbon content, using a continuous flow system consisting of a Delta V Plus mass spectrometer and a Flush 1112 elemental analyser via a Conflo IV universal interface. The δ(13)C values were normalized to constant lipid content using the equations proposed by McConnaughey and McRoy. Although statistically significant, the differences in δ(15)N values between the drying methods were small (mean differences ≤0.21‰). The differences in δ(13)C values between the drying methods were not statistically significant, and normalising the δ(13)C values to constant lipid content reduced the mean differences for all treatments to ≤0.65‰. A statistically significant difference of ~2% in C content existed between tissues dried in a food dehydrator and those dried in a freeze-dryer for two fish species. There was no significant effect of fish size on the differences between methods. No substantial effect of drying method was found on the δ(15)N or δ(13)C values of teleost muscle tissue. Copyright © 2013 John Wiley & Sons, Ltd.

Transducin Duplicates in the Zebrafish Retina and Pineal Complex: Differential Specialisation after the Teleost Tetraploidisation

PubMed Central

Lagman, David; Callado-Pérez, Amalia; Franzén, Ilkin E.

2015-01-01

Gene duplications provide raw materials that can be selected for functional adaptations by evolutionary mechanisms. We describe here the results of 350 million years of evolution of three functionally related gene families: the alpha, beta and gamma subunits of transducins, the G protein involved in vision. Early vertebrate tetraploidisations resulted in separate transducin heterotrimers: gnat1/gnb1/gngt1 for rods, and gnat2/gnb3/gngt2 for cones. The teleost-specific tetraploidisation generated additional duplicates for gnb1, gnb3 and gngt2. We report here that the duplicates have undergone several types of subfunctionalisation or neofunctionalisation in the zebrafish. We have found that gnb1a and gnb1b are co-expressed at different levels in rods; gnb3a and gnb3b have undergone compartmentalisation restricting gnb3b to the dorsal and medial retina, however, gnb3a expression was detected only at very low levels in both larvae and adult retina; gngt2b expression is restricted to the dorsal and medial retina, whereas gngt2a is expressed ventrally. This dorsoventral distinction could be an adaptation to protect the lower part of the retina from intense light damage. The ontogenetic analysis shows earlier onset of expression in the pineal complex than in the retina, in accordance with its earlier maturation. Additionally, gnb1a but not gnb1b is expressed in the pineal complex, and gnb3b and gngt2b are transiently expressed in the pineal during ontogeny, thus showing partial temporal subfunctionalisation. These retina-pineal distinctions presumably reflect their distinct functional roles in vision and circadian rhythmicity. In summary, this study describes several functional differences between transducin gene duplicates resulting from the teleost-specific tetraploidisation. PMID:25806532

Identification and lateral membrane localization of cyclin M3, likely to be involved in renal Mg2+ handling in seawater fish

PubMed Central

Islam, Zinia; Hayashi, Naoko; Inoue, Hana; Umezawa, Takahiro; Kimura, Yuuri; Doi, Hiroyuki; Romero, Michael F.; Hirose, Shigehisa

2014-01-01

The kidney of marine teleosts is the major site of Mg2+ excretion and produces urine with a high Mg2+ concentration. However, the transporters involved in Mg2+ excretion are poorly understood. The cyclin M (Cnnm; also known as ancient conserved domain protein) family comprises membrane proteins homologous to the bacterial Mg2+ and Co2+ efflux protein, CorC. To understand the molecular mechanism of Mg2+ homeostasis in marine teleosts, we analyzed the expression of the Cnnm family genes in the seawater (SW) pufferfish, torafugu (Takifugu rubripes), and the closely related euryhaline species, mefugu (Takifugu obscurus). Database mining and phylogenetic analysis indicated that the Takifugu genome contains six members of the Cnnm family: two orthologs of Cnnm1, one of Cnnm2, one of Cnnm3, and two of Cnnm4. RT-PCR analyses indicated that Cnnm2, Cnnm3, and Cnnm4a are expressed in the kidney, whereas other members are mainly expressed in the brain. Renal expression of Cnnm3 was upregulated in SW mefugu, whereas renal expression of Cnnm2 was upregulated in freshwater (FW) mefugu. No significant difference was observed in renal expression of Cnnm4a between SW and FW mefugu. In situ hybridization and immunohistochemical analyses of the SW mefugu kidney revealed that Cnnm3 is expressed in the proximal tubule, and its product localizes to the lateral membrane. When Cnnm3 was expressed in Xenopus laevis oocytes, whole cellular Mg2+ content and free intracellular Mg2+ activity significantly decreased. These results suggest that Cnnm3 is involved in body fluid Mg2+ homeostasis in marine teleosts. PMID:24965791

Morphology and vascular anatomy of the gills of a primitive air-breathing fish, the bowfin (Amia calva).

PubMed

Olson, K R

1981-01-01

The morphology of the gills of a primitive air breather (Amia calva) was examined by light microscopy of semithin sections of gill filaments, and gill perfusion pathways were identified by scanning-electron microscopic analysis of corrosion replicas prepared by intravascular injection of methyl methacrylate. The arrangement of gill filaments and respiratory lamellae is similar to that ot teleosts with the exception of an interfilamental support bar that is fused to the outer margins of lamellae on adjacent filaments. The prebranchial vasculature is also similar to that of teleosts, whereas the postbranchial circulation of arches III and IV is modified to permit selective perfusion of the air bladder. Gill filaments contain three distinct vascular systems: (1) the respiratory circulation which receives the entire cardiac output and perfuses the secondary lamellae; (2) a nutrient system that arises from the postlammelar circulation and perfuses filamental tissues; (3) a network of unknown function consisting of subepithelial sinusoids surrounding afferent and efferent margins of the filament and traversing the filament beneath the interlamellar epithelium. Prelamellar arteriovenous anastomoses (AVAs) are rare, postlammelar AVAs are common especially at the base of the filament where they form a dense network of small tortuous vessels before coalescing into a large filamental nutrient artery. Unlike in most teleosts, the outer vascular margins of the lamellae are embedded in the interfilamental support bar and become the sole vasculature of this tissue. Arterial-arterial lamellar bypass vessels were not observed. Previously observed decreases in oxygen transfer across the gills during air breathing can be explained only by redistribution of blood flow between or within the respiratory lamellae.

"Holostei versus Halecostomi" Problem: Insight from Cytogenetics of Ancient Nonteleost Actinopterygian Fish, Bowfin Amia calva.

PubMed

Majtánová, Zuzana; Symonová, Radka; Arias-Rodriguez, Lenin; Sallan, Lauren; Ráb, Petr

2017-11-01

Bowfin belongs to an ancient lineage of nonteleost ray-finned fishes (actinopterygians) and is the only extant survivor of a once diverged group, the Halecomorphi or Amiiformes. Owing to the scarcity of extant nonteleost ray-finned lineages, also referred as "living fossils," their phylogenetic interrelationships have been the target of multiple hypotheses concerning their sister group relationships. Molecular and morphological data sets have produced controversial results; bowfin is considered as either the sister group to genome-duplicated teleosts (together forming the group of Halecostomi) or to gars (Lepisosteiformes; together forming the group of Holostei). However, any detailed cytogenetic analysis of bowfin chromosomes has never been performed to address this issue. Here we examined bowfin chromosomes by conventional (Giemsa-staining, C-banding, base-specific fluorescence and silver staining) and molecular (FISH with rDNA probes) cytogenetic protocols. We identified diploid chromosome number 2n = 46 with a middle-sized submetacentric chromosome pair as the major ribosomal DNA-bearing (45S rDNA), GC-positive and silver-positive element. The minor rDNA (5S rDNA) sites were localized in the pericentromeric region of one middle-sized acrocentric chromosome pair. Comparison with available cytogenetic data of other nonteleost actinopterygians (bichirs, sturgeons, gars) and teleost species including representative of basally branching lineages showed bowfin chromosomal characteristics more similar to the teleost type than to any other nonteleosts. Particularly striking differences were identified between bowfin and gars, the latter of which were found to mimic mammalian AT/GC genomic organisation. Such conclusion however contradicts the most recent phylogenomic results and raises the question what states are ancestral and what are derived. © 2017 Wiley Periodicals, Inc.

Comparative study of four interleukin 17 cytokines of tongue sole Cynoglossus semilaevis: Genomic structure, expression pattern, and promoter activity.

PubMed

Chi, Heng; Sun, Li

2015-11-01

The interleukin (IL)-17 cytokine family participates in the regulation of many cellular functions. In the present study, we analyzed the genomic structure, expression, and promoter activity of four IL-17 members from the teleost fish tongue sole (Cynoglossus semilaevis), i.e. CsIL-17C CsIL-17D, CsIL-17F, and IL-17F like (IL-17Fl). We found that CsIL-17C, CsIL-17D, CsIL-17F, and CsIL-17Fl share 21.2%-28.6% overall sequence identities among themselves and 31.5%-71.2% overall sequence identities with their counterparts in other teleost. All four CsIL-17 members possess an IL-17 domain and four conserved cysteine residues. Phylogenetic analysis classified the four CsIL-17 members into three clusters. Under normal physiological conditions, the four CsIL-17 expressed in multiple tissues, especially non-immune tissues. Bacterial infection upregulated the expression of all four CsIL-17, while viral infection upregulated the expression of CsIL-17D and CsIL-17Fl but downregulated the expression of CsIL-17C and CsIL-17F. The 1.2 kb 5'-flanking regions of the four CsIL-17 exhibited apparent promoter activity and contain a number of putative transcription factor-binding sites. Furthermore, the promoter activities of CsIL-17C, CsIL-17D, and CsIL-17F, but not CsIL-17Fl, were modulated to significant extents by lipopolysaccharide, PolyI:C, and PMA. This study provides the first evidence that in teleost, different IL-17 members differ in expression pattern and promoter activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discovery of a unique Ig heavy-chain (IgT) in rainbow trout: Implications for a distinctive B cell developmental pathway in teleost fish

USGS Publications Warehouse

Hansen, J.D.; Landis, E.D.; Phillips, R.B.

2005-01-01

During the analysis of Ig superfamily members within the available rainbow trout (Oncorhynchus mykiss) EST gene index, we identified a unique Ig heavy-chain (IgH) isotype. cDNAs encoding this isotype are composed of a typical IgH leader sequence and a VDJ rearranged segment followed by four Ig superfamily C-1 domains represented as either membrane-bound or secretory versions. Because teleost fish were previously thought to encode and express only two IgH isotypes (IgM and IgD) for their humoral immune repertoire, we isolated all three cDNA isotypes from a single homozygous trout (OSU-142) to confirm that all three are indeed independent isotypes. Bioinformatic and phylogenetic analysis indicates that this previously undescribed divergent isotype is restricted to bony fish, thus we have named this isotype "IgT" (??) for teleost fish. Genomic sequence analysis of an OSU-142 bacterial artificial chromosome (BAC) clone positive for all three IgH isotypes revealed that IgT utilizes the standard rainbow trout VH families, but surprisingly, the IgT isotype possesses its own exclusive set of DH and JH elements for the generation of diversity. The IgT D and J segments and ?? constant (C) region genes are located upstream of the D and J elements for IgM, representing a genomic IgH architecture that has not been observed in any other vertebrate class. All three isotypes are primarily expressed in the spleen and pronephros (bone marrow equivalent), and ontogenically, expression of IgT is present 4 d before hatching in developing embryos. ?? 2005 by The National Academy of Sciences of the USA.

An exceptionally preserved Eocene shark and the rise of modern predator-prey interactions in the coral reef food web.

PubMed

Fanti, Federico; Minelli, Daniela; Conte, Gabriele Larocca; Miyashita, Tetsuto

2016-01-01

Following extreme climatic warming events, Eocene Lagerstätten document aquatic and terrestrial vertebrate faunas surprisingly similar to modern counterparts. This transition in marine systems is best documented in the earliest teleost-dominated coral reef assemblage of Pesciara di Bolca, northern Italy, from near the end of the Eocene Climatic Optimum. Its rich fauna shows similarities with that of the modern Great Barrier Reef in niche exploitation by and morphological disparity among teleost primary consumers. However, such paleoecological understanding has not transcended trophic levels above primary consumers, particularly in carcharhiniform sharks. We report an exceptionally preserved fossil school shark (Galeorhinus cuvieri) from Pesciara di Bolca. In addition to the spectacular preservation of soft tissues, including brain, muscles, and claspers, this male juvenile shark has stomach contents clearly identifiable as a sphyraenid acanthomorph (barracuda). This association provides evidence that a predator-prey relationship between Galeorhinus and Sphyraena in the modern coral reefs has roots in the Eocene. A growth curve of the living species of Galeorhinus fitted to G. cuvieri suggests that all specimens of G. cuvieri from the lagoonal deposits of Bolca represent sexually and somatically immature juveniles. The modern trophic association between higher-degree consumers (Galeorhinus and Sphyraena) has a counterpart in the Eocene Bolca, just as Bolca and the Great Barrier Reef show parallels among teleost primary consumers. Given the age of Bolca, trophic networks among consumers observed in modern coral reefs arose by the exit from the Climatic Optimum. The biased representation of juveniles suggests that the Bolca Lagerstätte served as a nursery habitat for G. cuvieri. Ultraviolet photography may be useful in probing for exceptional soft tissue preservation before common acid preparation methods.

Molecular cloning, expression pattern, and 3D structural prediction of the cold inducible RNA-binding protein (CIRP) in Japanese flounder ( Paralichthys olivaceus)

NASA Astrophysics Data System (ADS)

Yang, Xiao; Gao, Jinning; Ma, Liman; Li, Zan; Wang, Wenji; Wang, Zhongkai; Yu, Haiyang; Qi, Jie; Wang, Xubo; Wang, Zhigang; Zhang, Quanqi

2015-02-01

Cold-inducible RNA-binding protein (CIRP) is a kind of RNA binding proteins that plays important roles in many physiological processes. The CIRP has been widely studied in mammals and amphibians since it was first cloned from mammals. On the contrary, there are little reports in teleosts. In this study, the Po CIRP gene of the Japanese flounder was cloned and sequenced. The genomic sequence consists of seven exons and six introns. The putative PoCIRP protein of flounder was 198 amino acid residues long containing the RNA recognition motif (RRM). Phylogenetic analysis showed that the flounder PoCIRP is highly conserved with other teleost CIRPs. The 5' flanking sequence was cloned by genome walking and many transcription factor binding sites were identified. There is a CpGs region located in promoter and exon I region and the methylation state is low. Quantitative real-time PCR analysis uncovered that Po CIRP gene was widely expressed in adult tissues with the highest expression level in the ovary. The mRNA of the Po CIRP was maternally deposited and the expression level of the gene was regulated up during the gastrula and neurula stages. In order to gain the information how the protein interacts with mRNA, we performed the modeling of the 3D structure of the flounder PoCIRP. The results showed a cleft existing the surface of the molecular. Taken together, the results indicate that the CIRP is a multifunctional molecular in teleosts and the findings about the structure provide valuable information for understanding the basis of this protein's function.

Whole-genome single-nucleotide polymorphism (SNP) marker discovery and association analysis with the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content in Larimichthys crocea

PubMed Central

Xiao, Shijun; Wang, Panpan; Dong, Linsong; Zhang, Yaguang; Han, Zhaofang; Wang, Qiurong

2016-01-01

Whole-genome single-nucleotide polymorphism (SNP) markers are valuable genetic resources for the association and conservation studies. Genome-wide SNP development in many teleost species are still challenging because of the genome complexity and the cost of re-sequencing. Genotyping-By-Sequencing (GBS) provided an efficient reduced representative method to squeeze cost for SNP detection; however, most of recent GBS applications were reported on plant organisms. In this work, we used an EcoRI-NlaIII based GBS protocol to teleost large yellow croaker, an important commercial fish in China and East-Asia, and reported the first whole-genome SNP development for the species. 69,845 high quality SNP markers that evenly distributed along genome were detected in at least 80% of 500 individuals. Nearly 95% randomly selected genotypes were successfully validated by Sequenom MassARRAY assay. The association studies with the muscle eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content discovered 39 significant SNP markers, contributing as high up to ∼63% genetic variance that explained by all markers. Functional genes that involved in fat digestion and absorption pathway were identified, such as APOB, CRAT and OSBPL10. Notably, PPT2 Gene, previously identified in the association study of the plasma n-3 and n-6 polyunsaturated fatty acid level in human, was re-discovered in large yellow croaker. Our study verified that EcoRI-NlaIII based GBS could produce quality SNP markers in a cost-efficient manner in teleost genome. The developed SNP markers and the EPA and DHA associated SNP loci provided invaluable resources for the population structure, conservation genetics and genomic selection of large yellow croaker and other fish organisms. PMID:28028455

Suction generation in white-spotted bamboo sharks Chiloscyllium plagiosum.

PubMed

Wilga, Cheryl D; Sanford, Christopher P

2008-10-01

After the divergence of chondrichthyans and teleostomes, the structure of the feeding apparatus also diverged leading to alterations in the suction mechanism. In this study we investigated the mechanism for suction generation during feeding in white-spotted bamboo sharks, Chiloscyllium plagiosum and compared it with that in teleosts. The internal movement of cranial elements and pressure in the buccal, hyoid and pharyngeal cavities that are directly responsible for suction generation was quantified using sonomicrometry and pressure transducers. Backward stepwise multiple linear regressions were used to explore the relationship between expansion and pressure, accounting for 60-96% of the variation in pressure among capture events. The progression of anterior to posterior expansion in the buccal, hyoid and pharyngeal cavities is accompanied by the sequential onset of subambient pressure in these cavities as prey is drawn into the mouth. Gape opening triggers the onset of subambient pressure in the oropharyngeal cavities. Peak gape area coincides with peak subambient buccal pressure. Increased velocity of hyoid area expansion is primarily responsible for generating peak subambient pressure in the buccal and hyoid regions. Pharyngeal expansion appears to function as a sink to receive water influx from the mouth, much like that of compensatory suction in bidirectional aquatic feeders. Interestingly, C. plagiosum generates large suction pressures while paradoxically compressing the buccal cavity laterally, delaying the time to peak pressure. This represents a fundamental difference from the mechanism used to generate suction in teleost fishes. Interestingly, pressure in the three cavities peaks in the posterior to anterior direction. The complex shape changes that the buccal cavity undergoes indicate that, as in teleosts, unsteady flow predominates during suction feeding. Several kinematic variables function together, with great variation over long gape cycles to generate the low subambient pressures used by C. plagiosum to capture prey.

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.

Gene transcription ontogeny of hypothalamic-pituitary-thyroid axis development in early-life stage fathead minnow and zebrafish.

PubMed

Vergauwen, Lucia; Cavallin, Jenna E; Ankley, Gerald T; Bars, Chloé; Gabriëls, Isabelle J; Michiels, Ellen D G; Fitzpatrick, Krysta R; Periz-Stanacev, Jelena; Randolph, Eric C; Robinson, Serina L; Saari, Travis W; Schroeder, Anthony L; Stinckens, Evelyn; Swintek, Joe; Van Cruchten, Steven J; Verbueken, Evy; Villeneuve, Daniel L; Knapen, Dries

2018-05-04

The hypothalamic-pituitary-thyroid (HPT) axis is known to play a crucial role in the development of teleost fish. However, knowledge of endogenous transcription profiles of thyroid-related genes in developing teleosts remains fragmented. We selected two model teleost species, the fathead minnow (Pimephales promelas) and the zebrafish (Danio rerio), to compare the gene transcription ontogeny of the HPT axis. Control organisms were sampled at several time points during embryonic and larval development until 33 days post-fertilization. Total RNA was extracted from pooled, whole fish, and thyroid-related mRNA expression was evaluated using quantitative polymerase chain reaction. Gene transcripts examined included: thyrotropin-releasing hormone receptor (trhr), thyroid-stimulating hormone receptor (tshr), sodium-iodide symporter (nis), thyroid peroxidase (tpo), thyroglobulin (tg), transthyretin (ttr), deiodinases 1, 2, 3a, and 3b (dio1, dio2, dio3a and 3b), and thyroid hormone receptors alpha and beta (thrα and β). A loess regression method was successful in identifying maxima and minima of transcriptional expression during early development of both species. Overall, we observed great similarities between the species, including maternal transfer, at least to some extent, of almost all transcripts (confirmed in unfertilized eggs), increasing expression of most transcripts during hatching and embryo-larval transition, and indications of a fully functional HPT axis in larvae. These data will aid in the development of hypotheses on the role of certain genes and pathways during development. Furthermore, this provides a background reference dataset for designing and interpreting targeted transcriptional expression studies both for fundamental research and for applications such as toxicology. Copyright © 2018 Elsevier Inc. All rights reserved.

Regulation of gene expression mediating indeterminate muscle growth in teleosts.

PubMed

Ahammad, A K Shakur; Asaduzzaman, Md; Asakawa, Shuichi; Watabe, Shugo; Kinoshita, Shigeharu

2015-08-01

Teleosts are unique among vertebrates due to their indeterminate muscle growth, i.e., continued production of neonatal muscle fibers until death. However, the molecular mechanism(s) underlying this property is unknown. Here, we focused on the torafugu (Takifugu rubripes) myosin heavy chain gene, MYHM2528-1, which is specifically expressed in neonatal muscle fibers produced by indeterminate muscle growth. We examined the flanking region of MYHM2528-1 through an in vivo reporter assay using zebrafish (Danio rerio) and identified a 2100 bp 5'-flanking sequence that contained sufficient promoter activity to allow specific gene expression. The effects of enhanced promoter activity were observed at the outer region of the fast muscle and the dorsal edge of slow muscle in zebrafish larvae. At the juvenile stage, the promoter was specifically activated in small diameter muscle fibers scattered throughout fast muscle and in slow muscle near the septum separating slow and fast muscles. This spatio-temporal promoter activity overlapped with known myogenic zones involved in teleost indeterminate muscle growth. A deletion mutant analysis revealed that the -2100 to -600 bp 5'flanking sequence of MYHM2528-1 is essential for promoter activity. This region contains putative binding sites for several representative myogenesis-related transcription factors and nuclear factor of activated T-cell (NFAT), a transcription activator involved in regeneration of mammalian adult skeletal muscle. A significant reduction in the promoter activity of the MYHM2528-1 deletion constructs was observed in accordance with a reduction in the number of these binding sites, suggesting the involvement of specific transcription factors in indeterminate muscle growth. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Molecular characterization of Kiss2 receptor and in vitro effects of Kiss2 on reproduction-related gene expression in the hypothalamus of half-smooth tongue sole (Cynoglossus semilaevis).

PubMed

Wang, Bin; Liu, Quan; Liu, Xuezhou; Xu, Yongjiang; Shi, Bao

2017-08-01

Kisspeptin (Kiss) and its receptor, KissR (previously known as GPR54), play a critical role in the control of reproduction and puberty onset in mammals. Additionally, a number of studies have provided evidence of the existence of multiple Kiss/KissR systems in teleosts, but the physiological relevance and functions of these kisspeptin forms (Kiss1 and Kiss2) still remain to be investigated. To this end, we examined the direct actions of Kiss2 on hypothalamic functions in the half-smooth tongue sole (Cynoglossus semilaevis), a representative species of the order Pleuronectiformes. As a first step, the full-length cDNA for kiss2r was identified and kiss2r transcripts were shown to be widely expressed in various tissues, notably in the brain of tongue sole. Then, the effects of Kiss2 decapeptide on reproduction-related gene expression were evaluated using a primary hypothalamus culture system. Our results showed that neither gnrh2 nor gnrh3 mRNA levels were altered by Kiss2. However, Kiss2 significantly increased the amounts of gnih and kiss2 mRNAs. In contrast, Kiss2 elicited an evident inhibitory effect on both gnihr and kiss2r mRNA levels. To the best of our knowledge, this is the first description of a direct and differential regulation of reproduction-related gene expression by Kiss2 at the hypothalamus level of a teleost fish. Overall, this study provides novel information on the role of Kiss2/Kiss2R system in the reproductive function of teleosts. Copyright © 2017 Elsevier Inc. All rights reserved.

Specific cerebral heat shock proteins and histamine receptor cross-talking mechanisms promote distinct lead-dependent neurotoxic responses in teleosts

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

Giusi, Giuseppina; Alo, Raffaella; Crudo, Michele

Recent interests are beginning to be directed towards toxic neurobiological dysfunctions caused by lead (Pb) in aquatic vertebrates. In the present work, treatment with a maximum acceptable toxic concentration of this heavy metal was responsible for highly significant (p < 0.01) abnormal motor behaviors such as hyperactive movements in the teleost Thalassoma pavo and the same treatment accounted for significantly (p < 0.05) enhanced hyperventilating states. On the other hand, greater abnormal motor behaviors were detected in the presence of the histamine (HA) receptor subtype 2 (H{sub 2}R) antagonist cimetidine (Cim), as shown by the very robust (p < 0.001)more » increases of the two behavioral states. Interestingly, elevated expression levels of stress-related factors, i.e. heat shock protein70/90 (HSP90/70) orthologs were reported for the first time in hypothalamic and mesencephalic areas of Pb-treated teleosts. In particular, an up-regulation of HSP70 was readily detected when this heavy metal was given concomitantly with Cim, while the histamine subtype 3 antagonist (H{sub 3}R) thioperamide (Thio), instead, blocked Pb-dependent up-regulatory trends of both chaperones in mostly hypothalamic areas. Moreover, intense neuronal damages of the above brain regions coincided with altered expressions of HSP70 and HSP90 when treated only with Cim. Overall these first results show that distinct H{sub n}R are able to exert a net neuroprotective role arising from their interaction with chaperones in fish exposed to Pb-dependent stressful conditions making this a potentially key interaction especially for T. pavo, aquatic species which plays an important ecological role towards the survival of other commercially vital fishes.« less

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

Are we missing a mineralocorticoid in teleost fish? Effects of cortisol, deoxycorticosterone and aldosterone on osmoregulation, gill Na+,K+-ATPase activity and isoform mRNA levels in Atlantic salmon

USGS Publications Warehouse

McCormick, S.D.; Regish, A.; O'Dea, M. F.; Shrimpton, J.M.

2008-01-01

It has long been held that cortisol, acting through a single receptor, carries out both glucocorticoid and mineralocorticoid actions in teleost fish. The recent finding that fish express a gene with high sequence similarity to the mammalian mineralocorticoid receptor (MR) suggests the possibility that a hormone other than cortisol carries out some mineralocorticoid functions in fish. To test for this possibility, we examined the effect of in vivo cortisol, 11-deoxycorticosterone (DOC) and aldosterone on salinity tolerance, gill Na+,K+-ATPase (NKA) activity and mRNA levels of NKA α1a and α1b in Atlantic salmon. Cortisol treatment for 6–14 days resulted in increased, physiological levels of cortisol, increased gill NKA activity and improved salinity tolerance (lower plasma chloride after a 24 h seawater challenge), whereas DOC and aldosterone had no effect on either NKA activity or salinity tolerance. NKA α1a and α1b mRNA levels, which increase in response to fresh water and seawater acclimation, respectively, were both upregulated by cortisol, whereas DOC and aldosterone were without effect. Cortisol, DOC and aldosterone had no effect on gill glucocorticoid receptor GR1, GR2 and MR mRNA levels, although there was some indication of possible upregulation of GR1 by cortisol (p = 0.07). The putative GR blocker RU486 inhibited cortisol-induced increases in salinity tolerance, NKA activity and NKA α1a and α1b transcription, whereas the putative MR blocker spironolactone had no effect. The results provide support that cortisol, and not DOC or aldosterone, is involved in regulating the mineralocorticoid functions of ion uptake and salt secretion in teleost fish.

Hepatocyte Nuclear Factor 4α (HNF4α) Is a Transcription Factor of Vertebrate Fatty Acyl Desaturase Gene as Identified in Marine Teleost Siganus canaliculatus

PubMed Central

Dong, Yewei; Wang, Shuqi; Chen, Junliang; Zhang, Qinghao; Liu, Yang; You, Cuihong; Monroig, Óscar; Tocher, Douglas R.; Li, Yuanyou

2016-01-01

Rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the capability of biosynthesizing long-chain polyunsaturated fatty acids (LC-PUFA) from C18 precursors, and to possess a Δ4 fatty acyl desaturase (Δ4 Fad) which was the first report in vertebrates, and is a good model for studying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. In order to understand regulatory mechanisms of transcription of Δ4 Fad, the gene promoter was cloned and characterized in the present study. An upstream sequence of 1859 bp from the initiation codon ATG was cloned as the promoter candidate. On the basis of bioinformatic analysis, several binding sites of transcription factors (TF) including GATA binding protein 2 (GATA-2), CCAAT enhancer binding protein (C/EBP), nuclear factor 1 (NF-1), nuclear factor Y (NF-Y), hepatocyte nuclear factor 4α (HNF4α) and sterol regulatory element (SRE), were identified in the promoter by site-directed mutation and functional assays. HNF4α and NF-1 were confirmed to interact with the core promoter of Δ4 Fad by gel shift assay and mass spectrometry. Moreover, over-expression of HNF4α increased promoter activity in HEK 293T cells and mRNA level of Δ4 Fad in rabbitfish primary hepatocytes, respectively. The results indicated that HNF4α is a TF of rabbitfish Δ4 Fad. To our knowledge, this is the first report on promoter structure of a Δ4 Fad, and also the first demonstration of HNF4α as a TF of vertebrate Fad gene involved in transcription regulation of LC-PUFA biosynthesis. PMID:27472219

Polarization of immune responses in fish: The 'macrophages first' point of view.

PubMed

Wiegertjes, Geert F; Wentzel, Annelieke S; Spaink, Herman P; Elks, Philip M; Fink, Inge R

2016-01-01

In this review, we support taking polarized immune responses in teleost fish from a 'macrophage first' point of view, a hypothesis that reverts the dichotomous T helper (TH)1 and TH2 driving forces by building on the idea of conservation of innate immune responses in lower vertebrates. It is plausible that the initial trigger for macrophage polarization into M1 (inflammation) or M2 (healing) could rely only on sensing microbial/parasite infection or other innate danger signals, without the influence of adaptive immunity. Given the long and ongoing debate on the presence/absence of a typical TH1 cytokine environment and, in particular, TH2 cytokine environment in fish immune responses, it stands out that the presence of macrophages with polarized phenotypes, alike M1 and M2, have been relatively easy to demonstrate for fish. We summarize in short present knowledge in teleost fish on those cytokines considered most critical to the dichotomous development of TH1/M1 and TH2/M2 polarization, in particular, but not exclusively, interferon-γ and interleukin (IL)-4/IL-13. We review, in more detail, polarization of fish immune responses taken from the macrophage point of view for which we adopted the simple nomenclature of M1 and M2. We discuss inducible nitric oxide synthase, or NOS-2, as a reliable M1 marker and arginase-2 as a reliable M2 marker for teleost fish and discuss the value of these macrophage markers for the generation of zebrafish reporter lines to study M1/M2 polarization in vivo. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mucosal immunity and probiotics in fish.

PubMed

Lazado, Carlo C; Caipang, Christopher Marlowe A

2014-07-01

Teleost mucosal immunity has become the subject of unprecedented research studies in recent years because of its diversity and defining characteristics. Its immune repertoire is governed by the mucosa-associated lymphoid tissues (MALT) which are divided into gut-associated lymphoid tissues (GALT), skin-associated lymphoid tissues (SALT), and gill-associated lymphoid tissues (GIALT). The direct contact with its immediate environment makes the mucosal surfaces of fish susceptible to a wide variety of pathogens. The inherent immunocompetent cells and factors in the mucosal surfaces together with the commensal microbiota have pivotal role against pathogens. Immunomodulation is a popular prophylactic strategy in teleost and probiotics possess this beneficial feature. Most of the studies on the immunomodulatory properties of probiotics in fish mainly discussed their impacts on systemic immunity. In contrast, few of these studies discussed the immunomodulatory features of probiotics in mucosal surfaces and are concentrated on the influences in the gut. Significant attention should be devoted in understanding the relationship of mucosal immunity and probiotics as the present knowledge is limited and are mostly based on extrapolations of studies in humans and terrestrial vertebrates. In the course of the advancement of mucosal immunity and probiotics, new perspectives in probiotics research, e.g., probiogenomics have emerged. This review affirms the relevance of probiotics in the mucosal immunity of fish by revisiting and bridging the current knowledge on teleost mucosal immunity, mucosal microbiota and immunomodulation of mucosal surfaces by probiotics. Expanding the knowledge of immunomodulatory properties of probiotics especially on mucosal immunity is essential in advancing the use of probiotics as a sustainable and viable strategy for successful fish husbandry. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evolution of Space Dependent Growth in the Teleost Astyanax mexicanus

PubMed Central

Gallo, Natalya D.; Jeffery, William R.

2012-01-01

The relationship between growth rate and environmental space is an unresolved issue in teleosts. While it is known from aquaculture studies that stocking density has a negative relationship to growth, the underlying mechanisms have not been elucidated, primarily because the growth rate of populations rather than individual fish were the subject of all previous studies. Here we investigate this problem in the teleost Astyanax mexicanus, which consists of a sighted surface-dwelling form (surface fish) and several blind cave-dwelling (cavefish) forms. Surface fish and cavefish are distinguished by living in spatially contrasting environments and therefore are excellent models to study the effects of environmental size on growth. Multiple controlled growth experiments with individual fish raised in confined or unconfined spaces showed that environmental size has a major impact on growth rate in surface fish, a trait we have termed space dependent growth (SDG). In contrast, SDG has regressed to different degrees in the Pachón and Tinaja populations of cavefish. Mating experiments between surface and Pachón cavefish show that SDG is inherited as a dominant trait and is controlled by multiple genetic factors. Despite its regression in blind cavefish, SDG is not affected when sighted surface fish are raised in darkness, indicating that vision is not required to perceive and react to environmental space. Analysis of plasma cortisol levels showed that an elevation above basal levels occurred soon after surface fish were exposed to confined space. This initial cortisol peak was absent in Pachón cavefish, suggesting that the effects of confined space on growth may be mediated partly through a stress response. We conclude that Astyanax reacts to confined spaces by exhibiting SDG, which has a genetic component and shows evolutionary regression during adaptation of cavefish to confined environments. PMID:22870223

High abundance androgen receptor in goldfish brain: characteristics and seasonal changes

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

Pasmanik, M.; Callard, G.V.

1988-08-01

Testosterone (T) exerts its actions in brain directly via androgen receptors or, after aromatization to estradiol, via estrogen receptors. Brain aromatase activity in teleost fish is 100-1000 times greater than in mammals and would be expected to significantly reduce the quantity of androgen available for receptor binding. Experiments were carried out on the goldfish Carassius auratus to determine if androgen receptors are present in teleost brain and whether their physicochemical properties reflect elevated aromatase. Cytosolic and nuclear extracts were assayed with the use of (/sup 3/H)T and charcoal, Sephadex LH-20, or DNA-cellulose chromatography to separate bound and free steroids. Bindingmore » activity was saturable and had an equally high affinity for T and 5 alpha-dihydrotestosterone. Although mibolerone was a relatively weak competitor, the putative teleost androgen 11-ketotestosterone, methyltrienolone (R1881), estradiol, progesterone, and cortisol were poor ligands. Characteristics that distinguish this receptor from a steroid-binding protein in goldfish serum are the presence of binding activity in both nuclear and cytosolic extracts, a low rate of ligand-receptor dissociation, electrophoretic mobility, sedimentation properties in low vs. high salt, and tissue distribution. DNA cellulose-adhering and nonadhering forms were detected, but these did not differ in other variables measured. Although goldfish androgen receptors resembled those of mammals in all important physicochemical characteristics, they were unusually abundant compared to levels in rat brain, but comparable to levels in prostate and other male sex hormone target organs. Moreover, there were seasonal variations in total receptors, with a peak at spawning (April) 4- to 5-fold higher than values in reproductively inactive fish.« less

An assessment of the genotoxic impact of the Sea Empress oil spill by the measurement of DNA adduct levels in selected invertebrate and vertebrate species.

PubMed

Harvey, J S; Lyons, B P; Page, T S; Stewart, C; Parry, J M

1999-04-26

The grounding of the Sea Empress oil tanker resulted in the release of 72,000 tonnes of crude oil into Milford Haven, Wales, UK. Our initial studies indicated that this contamination resulted in elevated levels of DNA adducts in one of the area's native marine species Lipophrys pholis [B.P. Lyons, J.S. Harvey, J.M. Parry, An initial assessment of the genotoxic impact of the Sea Empress oil spill by the measurement of DNA adduct levels in the intertidal teleost Lipophrys pholis, Mutat. Res. 390 (1997) 263-268]. These original studies were extended and the genotoxic impact of the oil contamination was investigated in the invertebrates Halichondria panicea and Mytilus edulis, along with the vertebrate fish species L. pholis, Pleuronectes platessa and Limanda limanda. DNA adduct levels were assessed in these species over a period of 2-17 months after the incident. The studies indicate differences in the impact of acute oil contamination upon vertebrate and invertebrate species. The oil contamination did not induce any detectable elevations in adduct levels in the invertebrate species H. panicea and M. edulis. In contrast, the oil contamination did appear to induce adducts in the vertebrate teleost species L. pholis, P. platessa and Lim. limanda. Despite some difficulties in sampling, the data obtained 12-17 months after the spill suggested that the affected species recovered from the oil contamination. While the studies indicate that the genetic impact of the oil contamination was less severe than might have been expected, it remains possible that the DNA adducts detected in the teleosts could lead to genetic changes in these species in the future. Copyright 1999 Elsevier Science B.V.

Environmental and cortisol-mediated control of Ca(2+) uptake in tilapia (Oreochromis mossambicus).

PubMed

Lin, Chia-Hao; Kuan, Wei-Chun; Liao, Bo-Kai; Deng, Ang-Ni; Tseng, Deng-Yu; Hwang, Pung-Pung

2016-04-01

Ca(2+) is a vital element for many physiological processes in vertebrates, including teleosts, which live in aquatic environments and acquire Ca(2+) from their surroundings. Ionocytes within the adult gills or larval skin are critical sites for transcellular Ca(2+) uptake in teleosts. The ionocytes of zebrafish were found to contain transcellular Ca(2+) transporters, epithelial Ca(2+) channel (ECaC), plasma membrane Ca(2+)-ATPase 2 (PMCA2), and Na(+)/Ca(2+) exchanger 1b (NCX1b), providing information about the molecular mechanism of transcellular Ca(2+) transports mediated by ionocytes in fish. However, more evidence is required to establish whether or not a similar mechanism of transcellular Ca(2+) transport also exists in others teleosts. In the present study, ecac, pmca2, and ncx1 were found to be expressed in the branchial ionocytes of tilapia, thereby providing further support for the mechanism of transcellular Ca(2+) transport through ionocytes previously proposed for zebrafish. In addition, we also reveal that low Ca(2+) water treatment of tilapia stimulates Ca(2+) uptake and expression of ecac and cyp11b (the latter encodes a cortisol-synthesis enzyme). Treatment of tilapia with exogenous cortisol (20 mg/l) enhanced both Ca(2+) influx and ecac expression. Therefore, increased cyp11b expression is suggested to enhance Ca(2+) uptake capacity in tilapia exposed to low Ca(2+) water. Furthermore, the application of cortisol receptor antagonists revealed that cortisol may regulate Ca(2+) uptake through glucocorticoid and/or mineralocorticoid receptor (GR and/or MR) in tilapia. Taken together, the data suggest that cortisol may activate GR and/or MR to execute its hypercalcemic action by stimulating ecac expression in tilapia.

Evolution of Axis Specification Mechanisms in Jawed Vertebrates: Insights from a Chondrichthyan

PubMed Central

Coolen, Marion; Sauka-Spengler, Tatjana; Nicolle, Delphine; Le-Mentec, Chantal; Lallemand, Yvan; Silva, Corinne Da; Plouhinec, Jean-Louis; Robert, Benoît; Wincker, Patrick; Shi, De-Li; Mazan, Sylvie

2007-01-01

The genetic mechanisms that control the establishment of early polarities and their link with embryonic axis specification and patterning seem to substantially diverge across vertebrates. In amphibians and teleosts, the establishment of an early dorso-ventral polarity determines both the site of axis formation and its rostro-caudal orientation. In contrast, amniotes retain a considerable plasticity for their site of axis formation until blastula stages and rely on signals secreted by extraembryonic tissues, which have no clear equivalents in the former, for the establishment of their rostro-caudal pattern. The rationale for these differences remains unknown. Through detailed expression analyses of key development genes in a chondrichthyan, the dogfish Scyliorhinus canicula, we have reconstructed the ancestral pattern of axis specification in jawed vertebrates. We show that the dogfish displays compelling similarities with amniotes at blastula and early gastrula stages, including the presence of clear homologs of the hypoblast and extraembryonic ectoderm. In the ancestral state, these territories are specified at opposite poles of an early axis of bilateral symmetry, homologous to the dorso-ventral axis of amphibians or teleosts, and aligned with the later forming embryonic axis, from head to tail. Comparisons with amniotes suggest that a dorsal expansion of extraembryonic ectoderm, resulting in an apparently radial symmetry at late blastula stages, has taken place in their lineage. The synthesis of these results with those of functional analyses in model organisms supports an evolutionary link between the dorso-ventral polarity of amphibians and teleosts and the embryonic-extraembryonic organisation of amniotes. It leads to a general model of axis specification in gnathostomes, which provides a comparative framework for a reassessment of conservations both among vertebrates and with more distant metazoans. PMID:17440610

Copper toxicity in the spiny dogfish (Squalus acanthias): urea loss contributes to the osmoregulatory disturbance.

PubMed

De Boeck, G; Hattink, J; Franklin, N M; Bucking, C P; Wood, S; Walsh, P J; Wood, C M

2007-08-30

Previous research showed that the spiny dogfish, Squalus acanthias, is much more sensitive to silver exposure than typical marine teleosts. The aim of the present study was to investigate if spiny dogfish were equally sensitive to copper exposure and whether the toxic mechanisms were the same. We exposed cannulated and non-cannulated spiny dogfish to measured concentrations of Cu (nominally 0, 500, 1000 and 1500 microg L(-1) Cu) for 72-96 h. All Cu exposures induced acidosis and lactate accumulation of either a temporary (500 microg L(-1)) or more persistent nature (1000 and 1500 microg L(-1)). At the two highest Cu concentrations, gill Na(+)/K(+)-ATPase activities were reduced by 45% (1000 microg L(-1)) and 62% (1500 microg L(-1)), and plasma Na(+) and Cl(-) concentrations increased by approximately 50 mM each. At the same time urea excretion doubled and plasma urea dropped by approximately 100 mM. Together with plasma urea, plasma TMAO levels dropped proportionally, indicating that the general impermeability of the gills was compromised. Overall plasma osmolarity did not change. Cu accumulation was limited with significant increases in plasma Cu and elevated gill and kidney Cu burdens at 1000 and 1500 microg L(-1). We conclude that Cu, like Ag, exerts toxic effect on Na(+)/K(+)-ATPase activities in the shark similar to those of teleosts, but there is an additional toxic action on elasmobranch urea retention capacities. With a 96 h LC(50) in the 800-1000 microg L(-1) range, overall sensitivity of spiny dogfish for Cu is, in contrast with its sensitivity to Ag, only slightly lower than in typical marine teleosts.

Expression and Sequence Evolution of Aromatase cyp19a1 and Other Sexual Development Genes in East African Cichlid Fishes

PubMed Central

Böhne, Astrid; Heule, Corina; Boileau, Nicolas; Salzburger, Walter

2013-01-01

Sex determination mechanisms are highly variable across teleost fishes and sexual development is often plastic. Nevertheless, downstream factors establishing the two sexes are presumably conserved. Here, we study sequence evolution and gene expression of core genes of sexual development in a prime model system in evolutionary biology, the East African cichlid fishes. Using the available five cichlid genomes, we test for signs of positive selection in 28 genes including duplicates from the teleost whole-genome duplication, and examine the expression of these candidate genes in three cichlid species. We then focus on a particularly striking case, the A- and B-copies of the aromatase cyp19a1, and detect different evolutionary trajectories: cyp19a1A evolved under strong positive selection, whereas cyp19a1B remained conserved at the protein level, yet is subject to regulatory changes at its transcription start sites. Importantly, we find shifts in gene expression in both copies. Cyp19a1 is considered the most conserved ovary-factor in vertebrates, and in all teleosts investigated so far, cyp19a1A and cyp19a1B are expressed in ovaries and the brain, respectively. This is not the case in cichlids, where we find new expression patterns in two derived lineages: the A-copy gained a novel testis-function in the Ectodine lineage, whereas the B-copy is overexpressed in the testis of the speciest-richest cichlid group, the Haplochromini. This suggests that even key factors of sexual development, including the sex steroid pathway, are not conserved in fish, supporting the idea that flexibility in sexual determination and differentiation may be a driving force of speciation. PMID:23883521

The expression of VILL protein is hypoosmotic-dependent in the lamellar gill ionocytes of Otocephala teleost fish, Chanos chanos.

PubMed

Kang, Chao-Kai; Lin, Chia-Shian; Hu, Yao-Chung; Tsai, Shu-Chuan; Lee, Tsung-Han

2017-01-01

Milkfish, a species within the primitive teleost lineage Otocephala, can survive in water conditions ranging from hypo- to hyper-saline. This study explored the effects of environmental salinity on apical morphologies of ionocytes and the expression of villin homologs in the gills of milkfish acclimated to either seawater (SW) or fresh water (FW). Scanning electron microscopy revealed that the ionocytes in the gill filaments of SW and FW milkfish, respectively, cellular apical morphologies were hole-type and squint-type. The flat-type ionocytes were observed in the gill lamellae of FW milkfish. Furthermore, apical surfaces of some lamellar ionocytes exhibited microvilli. Villin 1 is a microvilli marker expressed in the epithelial cells of various vertebrates. In the phylogenetic tree of villin 1 homologs, primitive teleosts exhibit villin 1-like (VILL) and villin 1 proteins. Two mRNA sequences, villin 1 and VILL, were identified from the milkfish transcriptome by next generation sequencing. Low but constant expression of villin 1 (gene and protein) was observed in the gills for both SW and FW fish. VILL gene and protein expression levels in the gills were higher in FW fish, compared to SW fish. Double immunofluorescence staining demonstrated that VILL protein was present in some lamellar ionocytes of FW milkfish, but not in the filament ionocytes of either FW or SW milkfish. Taken together, these findings indicated that the VILL expression of ionocytes is hypoosmotic-dependent. The VILL might be involved in the formation of microvilli in the lamellar ionocytes for hyperosmoregulation of the milkfish. Copyright © 2016 Elsevier Inc. All rights reserved.

Proteomic analysis of rainbow trout (Oncorhynchus mykiss) intestinal epithelia: physiological acclimation to short-term starvation.

PubMed

Baumgarner, Bradley L; Bharadwaj, Anant S; Inerowicz, Dorota; Goodman, Angela S; Brown, Paul B

2013-03-01

The intestinal epithelia form the first line of defense against harmful agents in the gut lumen of most monogastric vertebrates, including teleost fishes. Previous investigations into the effect of starvation on the intestinal epithelia of teleost fishes have focused primarily on changes in morphological characteristics and targeted molecular analysis of specific enzymes. The goal of this study was to use a comprehensive approach to help reveal how the intestinal epithelia of carnivorous teleost fishes acclimate to short-term nutrient deprivation. We utilized two-dimensional gel electrophoresis (2-DE) to conduct the proteomic analysis of the mucosal and epithelial layer of the anterior gut intestinal tract (GIT) from satiation fed vs. 4 week starved rainbow trout (Oncorhynchus mykiss). A total of 40 proteins were determined to be differentially expressed and were subsequently picked for in-gel trypsin digestion. Peptide mass fingerprint analysis was conducted using matrix assisted laser desorption time-of-flight/time-of-flight. Nine of the 11 positively identified proteins were directly related to innate immunity. The expression of α-1 proteinase inhibitor decreased in starved vs. fed fish. Also, the concentration of one leukocyte elastase inhibitor (LEI) isomer decreased in starved fish, though the concentration of another LEI isomer increased in due to starvation. In addition, starvation promoted an increased concentration of the important xenobiotic-transporter p-glycoprotein. Finally, starvation resulted in a significant increase in type II keratin E2. Overall, our results indicate that starvation promoted a reduced capacity to inhibit enzymatic stress but increased xenobiotic resistance and paracellular permeability of epithelial cells in the anterior intestine of rainbow trout. Copyright © 2012 Elsevier Inc. All rights reserved.

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.

A second corticotropin-releasing hormone gene (CRH2) is conserved across vertebrate classes and expressed in the hindbrain of a basal neopterygian fish, the spotted gar (Lepisosteus oculatus).

PubMed

Grone, Brian P; Maruska, Karen P

2015-05-01

To investigate the origins of the vertebrate stress-response system, we searched sequenced vertebrate genomes for genes resembling corticotropin-releasing hormone (CRH). We found that vertebrate genomes possess, in addition to CRH, another gene that resembles CRH in sequence and syntenic environment. This paralogous gene was previously identified only in the elephant shark (a holocephalan), but we find it also in marsupials, monotremes, lizards, turtles, birds, and fishes. We examined the relationship of this second vertebrate CRH gene, which we name CRH2, to CRH1 (previously known as CRH) and urocortin1/urotensin1 (UCN1/UTS1) in primitive fishes, teleosts, and tetrapods. The paralogs CRH1 and CRH2 likely evolved via duplication of CRH during a whole-genome duplication early in the vertebrate lineage. CRH2 was subsequently lost in both teleost fishes and eutherian mammals but retained in other lineages. To determine where CRH2 is expressed relative to CRH1 and UTS1, we used in situ hybridization on brain tissue from spotted gar (Lepisosteus oculatus), a neopterygian fish closely related to teleosts. In situ hybridization revealed widespread distribution of both crh1 and uts1 in the brain. Expression of crh2 was restricted to the putative secondary gustatory/secondary visceral nucleus, which also expressed calcitonin-related polypeptide alpha (calca), a marker of parabrachial nucleus in mammals. Thus, the evolutionary history of CRH2 includes restricted expression in the brain, sequence changes, and gene loss, likely reflecting release of selective constraints following whole-genome duplication. The discovery of CRH2 opens many new possibilities for understanding the diverse functions of the CRH family of peptides across vertebrates. © 2015 Wiley Periodicals, Inc.

Optimized conditions for primary culture of pituitary cells from the Atlantic cod (Gadus morhua). The importance of osmolality, pCO₂, and pH.

PubMed

Hodne, Kjetil; von Krogh, Kristine; Weltzien, Finn-Arne; Sand, Olav; Haug, Trude M

2012-09-01

Protocols for primary cultures of teleost cells are commonly only moderately adjusted from similar protocols for mammalian cells, the main adjustment often being of temperature. Because aquatic habitats are in general colder than mammalian body temperatures and teleosts have gills in direct contact with water, pH and buffer capacity of blood and extracellular fluid are different in fish and mammals. Plasma osmolality is generally higher in marine teleosts than in mammals. Using Atlantic cod (Gadus morhua) as a model, we have optimized these physiological parameters to maintain primary pituitary cells in culture for an extended period without loosing key properties. L-15 medium with adjusted osmolality, adapted to low pCO(2) (3.8mm Hg) and temperature (12°C), and with pH 7.85, maintained the cells in a physiologically sounder state than traditional culture medium, significantly improving cell viability compared to the initial protocol. In the optimized culture medium, resting membrane potential and response to releasing hormone were stable for at least two weeks, and the proportion of cells firing action potentials during spawning season was about seven times higher than in the original culture medium. The cells were moderately more viable when the modified medium was supplemented with newborn calf serum or artificial serum substitute. Compared to serum-free L-15 medium, expression of key genes (lhb, fshb, and gnrhr2a) was better maintained in medium containing SSR, whereas NCS tended to decrease the expression level. Although serum-free medium is adequate for many applications, serum supplement may be preferable for experiments dependent on membrane integrity. Copyright © 2012 Elsevier Inc. 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.

TARGET ORGAN TOXICITY IN MARINE AND FRESHWATER TELEOSTS: VOLUME 1 - ORGANS

EPA Science Inventory

In any given aquatic ecosystem, fish serve a multitude of critical functions and so, are typically included in the risk assessment of various chemicals in waterways. However, uncertainties in toxicity evaluation can arise since these assessments are usually based solely on acute ...

TARGET ORGAN TOXICITY IN MARINE AND FRESHWATER TELEOSTS: VOLUME 2 - SYSTEMS

EPA Science Inventory

In any given aquatic ecosystem, fish serve a multitude of critical functions and so, are typically included in the risk assessment of various chemicals in waterways. However, uncertainties in toxicity evaluation can arise since these assessments are usually based solely on acute ...

Pre-spawning parental stress affects channel catfish, Ictalurus punctatus reproduction and subsequent progeny performance

USDA-ARS?s Scientific Manuscript database

Routine fish handling procedures associated with seining, selecting, transportation, crowding, weighing, and stripping have shown to cause negative physiological responses to hatchery performance. In teleosts, cortisol is the main corticosteroid released during stress, and hence, plasma cortisol co...

COMPARATIVE VITELLOGENIC RESPONSES IN THREE TELEOST SPECIES: EXTRAPOLATION TO IN SITU FIELD STUDIES

EPA Science Inventory

Induction of vitellogenin (VTG) was compared among three teleostean species to determine their relative sensitivity of exposure to 17b-estradiol (E2). Japanese medaka (Oryzias latipes), sunshine bass (Morone saxatalis x Morone chrysops) and channel catfish (Ictalurus punctatus) ...

MACROPHAGE AGGREGATES AS BIOMARKERS OF EXPOSURE: FROM FERAL POPULATIONS TO LABORATORY MODELS

EPA Science Inventory

Macrophage aggregates (MAs) are structures within the spleen, kidney and sometimes liver of teleost fishes. They are believed to function much like primitive lymph nodes in that phagocytized material is transported to these areas by macrophages, for destruction, recycling or stor...

A rich diversity of opercle bone shape among teleost fishes

PubMed Central

Small, Clayton M.; Knope, Matthew L.

2017-01-01

The opercle is a prominent craniofacial bone supporting the gill cover in all bony fish and has been the subject of morphological, developmental, and genetic investigation. We surveyed the shapes of this bone among 110 families spanning the teleost tree and examined its pattern of occupancy in a principal component-based morphospace. Contrasting with expectations from the literature that suggest the local morphospace would be only sparsely occupied, we find primarily dense, broad filling of the morphological landscape, indicating rich diversity. Phylomorphospace plots suggest that dynamic evolution underlies the observed spatial patterning. Evolutionary transits through the morphospaces are sometimes long, and occur in a variety of directions. The trajectories seem to represent both evolutionary divergences and convergences, the latter supported by convevol analysis. We suggest that that this pattern of occupancy reflects the various adaptations of different groups of fishes, seemingly paralleling their diverse marine and freshwater ecologies and life histories. Opercle shape evolution within the acanthomorphs, spiny ray-finned fishes, appears to have been especially dynamic. PMID:29281662

Characterization of the molecular chaperone calnexin in the channel catfish, Ictalurus punctatus, and its association with MHC class II molecules.

PubMed

Fuller, James R; Pitzer, Joshua E; Godwin, Ulla; Albertino, Mark; Machon, Benjamin D; Kearse, Kelly P; McConnell, Thomas J

2004-05-17

Folding and assembly of MHC molecules in mammals occurs in the endoplasmic reticulum (ER), but has not been studied in teleosts. Calnexin (CNX) is an ER chaperone that associates with glycoproteins bearing a monoglucosylated N-linked oligosaccharide side chain. Here we report the first identification and characterization of a full-length CNX cDNA clone in a teleost, and the association of the CNX chaperone with MHC class II in a channel catfish T cell line. The 1.8 kb CNX clone encodes a protein of 607 amino acids that is 72% identical to the consensus sequence of mammalian CNXs. The association of CNX with class II is of particular interest because the native MHC class II alpha chain of Ictalurus punctatus does not bear any N-linked oligosaccharide consensus glycosylation sequences. Thus the assembly of class II molecules in the catfish probably proceeds via different steps than occurs in mammals. Copyright 2003 Elsevier Ltd.

Fundulus as the Premier Teleost Model in Environmental Biology: Opportunities for New Insights Using Genomics

PubMed Central

Burnett, Karen G.; Bain, Lisa J.; Baldwin, William S.; Callard, Gloria V.; Cohen, Sarah; Di Giulio, Richard T.; Evans, David H.; Gómez-Chiarri, Marta; Hahn, Mark E.; Hoover, Cindi A.; Karchner, Sibel I.; Katoh, Fumi; MacLatchy, Deborah L.; Marshall, William S.; Meyer, Joel N.; Nacci, Diane E.; Oleksiak, Marjorie F.; Rees, Bernard B.; Singer, Thomas D.; Stegeman, John J.; Towle, David W.; Van Veld, Peter A.; Vogelbein, Wolfgang K.; Whitehead, Andrew; Winn, Richard N.; Crawford, Douglas L.

2007-01-01

A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms. PMID:18071578

Molecular profile of the unique species of traditional Chinese medicine, Chinese seahorse (Hippocampus kuda Bleeker).

PubMed

Zhang, Ning; Xu, Bin; Mou, Chunyan; Yang, Wenli; Wei, Jianwen; Lu, Liang; Zhu, Junjie; Du, Jingchun; Wu, Xiaokun; Ye, Lanting; Fu, Zhiyan; Lu, Yang; Lin, Jianghai; Sun, Zizi; Su, Jing; Dong, Meiling; Xu, Anlong

2003-08-28

A cDNA library of male Chinese seahorse (Hippocampus kuda Bleeker) was constructed to investigate the molecular profile of seahorse as one of the most famous traditional Chinese medicine materials, and to reveal immunological and physiological mechanisms of seahorse as one of the most primitive vertebrates at molecular level. A total of 3372 expressed sequence tags (ESTs) consisting of 1911 unique genes (345 clusters and 1566 singletons) were examined in the present study. Identification of the genes related to immune system, paternal brooding and physiological regulation provides not only valuable insights into the molecular mechanism of immune system in teleost fish but also plausible explanations for pharmacological activities of Chinese seahorse. Furthermore, the occurrence of high prevalent C-type lectins suggested that a lectin-complement pathway might exert a more dominant function in the innate immune system of teleost than mammal. Carbohydrate recognition domain (CRD) without a collagen-like region in the lectins of seahorse was likely an ancient characteristic of lectins similar to invertebrates.

Next-generation sequencing of the yellowfin tuna mitochondrial genome reveals novel phylogenetic relationships within the genus Thunnus.

PubMed

Guo, Liang; Li, Mingming; Zhang, Heng; Yang, Sen; Chen, Xinghan; Meng, Zining; Lin, Haoran

2016-05-01

Recently, the next-generation sequencing (NGS) technology has become a powerful tool for sequencing the teleost mitochondrial genome (mitogenome). Here, we used this technology to determine the mitogenome of the yellowfin tuna (Thunnus albacares). A total of 41,378 reads were generated by Illumina platform with an average depth of 250×. The mitogenome (16,528 bp in length) contained 37 mitochondrial genes with the similar gene order to other typical teleosts. These mitochondrial genes were encoded on the heavy strand except for ND6 and eight tRNA genes. The result of phylogenetic analysis supported two distinct clades dividing the genus Thunnus, but the tuna species of these two genetic clades were different from that of two recognized subgenus based on anatomical characters and geographical distribution. Our results might help to understand the structure, function, and evolutionary history of the yellowfin tuna mitogenome and also provide valuable new insights for phylogenetic affinity of tuna species.

Segmentation of the zebrafish axial skeleton relies on notochord sheath cells and not on the segmentation clock.

PubMed

Lleras Forero, Laura; Narayanan, Rachna; Huitema, Leonie Fa; VanBergen, Maaike; Apschner, Alexander; Peterson-Maduro, Josi; Logister, Ive; Valentin, Guillaume; Morelli, Luis G; Oates, Andrew C; Schulte-Merker, Stefan

2018-04-06

Segmentation of the axial skeleton in amniotes depends on the segmentation clock, which patterns the paraxial mesoderm and the sclerotome. While the segmentation clock clearly operates in teleosts, the role of the sclerotome in establishing the axial skeleton is unclear. We severely disrupt zebrafish paraxial segmentation, yet observe a largely normal segmentation process of the chordacentra. We demonstrate that axial entpd5+ notochord sheath cells are responsible for chordacentrum mineralization, and serve as a marker for axial segmentation. While autonomous within the notochord sheath, entpd5 expression and centrum formation show some plasticity and can respond to myotome pattern. These observations reveal for the first time the dynamics of notochord segmentation in a teleost, and are consistent with an autonomous patterning mechanism that is influenced, but not determined by adjacent paraxial mesoderm. This behavior is not consistent with a clock-type mechanism in the notochord. © 2018, Lleras Forero et al.

Feeding habits of an endemic fish, Oxygymnocypris stewartii, in the Yarlung Zangbo River in Tibet, China

USGS Publications Warehouse

Huo, Bin; Xie, Cong Xin; Madenjian, Charles P.; Ma, Bao Shan; Yang, Xue Feng; Huang, Hai Ping

2014-01-01

Feeding habits of Oxygymnocypris stewartii were investigated based on monthly sampling in the Yarlung Zangbo River from August 2008 to August 2009. The gut contents of 194 individuals were analysed and quantified with numerical and gravimetric methods. This species can be considered a generalized and opportunistic predator feeding both on teleosts and aquatic insects. A multivariate analysis revealed noticeable variation in O. stewartii diet composition with fish size and season. The smaller specimens fed primarily on Cobitidae and Hydropsychidae. As they grew, Cyprinidae and Chironomidae larvae became important prey. The preferred food items were teleosts in summer and autumn. For winter and spring, the predominant prey switched to chironomidae larvae. Diet composition did not significantly vary between the sexes. Finally, a significant and positive correlation between predator and prey length was found. These findings provide the fundamental information better understanding the role of this important endemic species in the Yarlung Zangbo River food web.

Sequence features and phylogenetic analysis of the stress protein Hsp90α in chinook salmon Oncorhynchus tshawytscha, a poikilothermic vertebrate

USGS Publications Warehouse

Palmisano, Aldo N.; Winton, James R.; Dickhoff, Walton W.

1999-01-01

We cloned and sequenced a chinook salmon Hsp90 cDNA; sequence analysis shows it to be Hsp90??. Phylogenetic analysis supports the hypothesis that ?? and ?? paralogs of Hsp90 arose as a result of a gene duplication event and that they diverged early in the evolution of vertebrates, before tetrapods separated from the teleost lineage. Among several differences distinguishing poikilothermic Hsp90?? sequences from their bird and mammal orthologs, the teleost versions specifically lack a characteristic QTQDQP phosphorylation site near the N-terminus. We used the cDNA to develop an RNA (Northern) blot to quantify cellular Hsp90 mRNA levels. Chinook salmon embryonic (CHSE-214) cells responded to heat shock with a rapid rise in Hsp90 mRNA through 4 h, followed by a gradual decline over the next 20 h. Hsp90 mRNA level may be useful as a stress indicator, especially in a laboratory setting or in response to acute heat stress.

New insights into gill ionocyte and ion transporter function in euryhaline and diadromous fish

USGS Publications Warehouse

Hiroi, Junya; McCormick, Stephen D.

2012-01-01

Teleost fishes are able to acclimatize to seawater by secreting excess NaCl by means of specialized “ionocytes” in the gill epithelium. Antibodies against Na+/K+-ATPase (NKA) have been used since 1996 as a marker for identifying branchial ionocytes. Immunohistochemistry of NKA by itself and in combination with Na+/K+/2Cl− cotransporter and CFTR Cl− channel provided convincing evidence that ionocytes are functional during seawater acclimation, and also revealed morphological variations in ionocytes among teleost species. Recent development of antibodies to freshwater- and seawater-specific isoforms of the NKA alpha-subunit has allowed functional distinction of ion absorptive and secretory ionocytes in Atlantic salmon. Cutaneous ionocytes of tilapia embryos serve as a model for branchial ionocytes, allowing identification of 4 types: two involved in ion uptake, one responsible for salt secretion and one with unknown function. Combining molecular genetics, advanced imaging techniques and immunohistochemistry will rapidly advance our understanding of both the unity and diversity of ionocyte function and regulation in fish osmoregulation.

Acute spill-mimicking exposure effect of hexavalent chromium on the pituitary-ovarian axis of a teleost, Channa punctatus (Bloch).

PubMed

Mishra, Ashish K; Mohanty, Banalata

2014-05-01

Acute exposure to hexavalent chromium (as 10, 20, and 40 mg/L potassium dichromate for 96 h) adversely affected the pituitary-ovarian axis of a teleost Channa punctatus. The toxic impact of metal exposure on fish ovary was revealed in the form of increased percentage of atretic follicles, significantly in 20 mg/L and 40 mg/L exposure groups. The follicular atresia mostly occurred in vitellogenic (stage II and stage III) oocytes. Reduction of serum level of 17β-estradiol was also significant in 20 mg/L and 40 mg/L exposure groups. The increase of LH-immunointensity of pituitary gonadotrophs (LHβ-immunoreactive cells) and their hypertrophy was evident, significantly in fish of 40 mg/L exposed group. Thus, the present acute metal spill-mimicking laboratory study clearly demonstrated that short-term exposures to high doses of hexavalent chromium may disrupt reproduction of the fish and affect their population. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

Molecular cloning and characterization of preproorexin in winter skate (Leucoraja ocellata).

PubMed

MacDonald, Erin E; Volkoff, Hélène

2010-12-01

A 815 base pairs (bp) cDNA encoding for preproorexin (preproOX) was cloned in winter skate, a cartilaginous fish. Winter skate preproOX is 159 amino acids (aa) long and contains a 34 aa orexin A and 28 aa orexin B. The amino acid sequence of winter skate preproOX is more similar to tetrapod preproOXs (36-40% identity) than teleost preproOXs (23-33% identity). Whereas orexin B appears relatively well conserved among vertebrates, orexin A displays more variability, in particular due to an "insertion sequence" that is present in teleost fish, but not in skate and tetrapods. RT-PCR studies show that preproOX mRNA has a widespread distribution within the brain and is present in several peripheral tissues, including gastrointestinal tract, heart and testes. Fasting induced increases in preproOX expression in the hypothalamus, suggesting that orexin might play a role in the regulation of food intake in winter skate. Copyright © 2010 Elsevier Inc. All rights reserved.

Electrosensory ampullary organs are derived from lateral line placodes in cartilaginous fishes

PubMed Central

Gillis, J. Andrew; Modrell, Melinda S.; Northcutt, R. Glenn; Catania, Kenneth C.; Luer, Carl A.; Baker, Clare V. H.

2016-01-01

Summary Ampullary organ electroreceptors excited by weak cathodal electric fields are used for hunting by both cartilaginous and non-teleost bony fishes. Despite similarities of neurophysiology and innervation, their embryonic origins remain controversial: bony fish ampullary organs are derived from lateral line placodes, while a neural crest origin has been proposed for cartilaginous fish electroreceptors. This calls into question the homology of electroreceptors and ampullary organs in the two lineages of jawed vertebrates. Here, we test the hypothesis that lateral line placodes form electroreceptors in cartilaginous fishes by undertaking the first long-term in vivo fate-mapping study in any cartilaginous fish. Using DiI-tracing for up to 70 days in the little skate, Leucoraja erinacea, we show that lateral line placodes form both ampullary electroreceptors and mechanosensory neuromasts. These data confirm the homology of electroreceptors and ampullary organs in cartilaginous and non-teleost bony fishes and indicate that jawed vertebrates primitively possessed a lateral line placode-derived system of electrosensory ampullary organs and mechanosensory neuromasts. PMID:22833123

Species-specific patterns of hyperostosis in marine teleost fishes

USGS Publications Warehouse

Smith-Vaniz, William F.; Kaufman, L.S.; Glowacki, J.

1995-01-01

The occurrence of swollen or hyperostotic bones in skeletal preparations, preserved museum material or whole fresh specimens of marine teleost fishes was identified in 92 species belonging to 22 families. Patterns of hyperostotic skeletal growth were typically consistent and often species-specific in all individuals larger than a certain size. The taxonomic distribution of hyperostosis in diverse phylogenetic groups suggests that it has arisen independently many times. Selected bones from two species of the family Carangidae, horse-eye jack Caranx latus Agassiz and crevalle jackCaranx hippos (Linnaeus), were examined in detail by light and electron microscopy. Nonhyperostotic bone contained osteoid-producing osteoblasts, resorbing osteoclasts, occasional osteocytes, and a rich vascular network, all characteristics of cellular bone. Thus, these fishes have a spatial juxtaposition of cellular and acellular bone tissues in adjacent and often serially homologous bone sites. The functional significance of hyperostosis is unknown, but it is a predictable manifestation of bone growth and development for the many taxa in which it occurs.