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Sample records for affect larval growth

  1. Dietary phosphorus affects the growth of larval Manduca sexta.

    PubMed

    Perkins, Marc C; Woods, H Arthur; Harrison, Jon F; Elser, James J

    2004-03-01

    Although phosphorus has long been considered an important factor in the growth of diverse biota such as bacteria, algae, and zooplankton, insect nutrition has classically focused on dietary protein and energy content. However, research in elemental stoichiometry has suggested that primary producer biomass has similar N:P ratios in aquatic and terrestrial systems, and phosphorus-rich herbivores in freshwater systems frequently face phosphorus-limited nutritional conditions. Therefore, herbivorous insects should also be prone to phosphorus limitation. We tested this prediction by rearing Manduca sexta larvae on artificial and natural (Datura wrightii leaves) diets containing varying levels of phosphorus (approximately 0.20, 0.55, or 1.2% phosphorus by dry weight). For both artificial and natural diets, increased dietary phosphorus significantly increased growth rates and body phosphorus contents, and shortened the time to the final instar molt. Caterpillars did not consistently exhibit compensatory feeding for phosphorus on either type of diet. The growth and body phosphorus responses were not explicable by changes in amounts of potassium or calcium, which co-varied with phosphorus in the diets. Concentrations of phosphorus in D. wrightii leaves collected in the field varied over a range in which leaf phosphorus is predicted to affect M. sexta's growth rates. These results suggest that natural variation in dietary phosphorus is likely to affect the growth rate and population dynamics of M. sexta, and perhaps larval insects more generally.

  2. Rearing Tenebrio molitor in BLSS: Dietary fiber affects larval growth, development, and respiration characteristics

    NASA Astrophysics Data System (ADS)

    Li, Leyuan; Stasiak, Michael; Li, Liang; Xie, Beizhen; Fu, Yuming; Gidzinski, Danuta; Dixon, Mike; Liu, Hong

    2016-01-01

    Rearing of yellow mealworm (Tenebrio molitor L.) will provide good animal nutrition for astronauts in a bioregenerative life support system. In this study, growth and biomass conversion data of T. molitor larvae were tested for calculating the stoichiometric equation of its growth. Result of a respiratory quotient test proved the validity of the equation. Fiber had the most reduction in mass during T. molitor‧s consumption, and thus it is speculated that fiber is an important factor affecting larval growth of T. molitor. In order to further confirm this hypothesis and find out a proper feed fiber content, T. molitor larvae were fed on diets with 4 levels of fiber. Larval growth, development and respiration in each group were compared and analyzed. Results showed that crude-fiber content of 5% had a significant promoting effect on larvae in early instars, and is beneficial for pupa eclosion. When fed on feed of 5-10% crude-fiber, larvae in later instars reached optimal levels in growth, development and respiration. Therefore, we suggest that crude fiber content in feed can be controlled within 5-10%, and with the consideration of food palatability, a crude fiber of 5% is advisable.

  3. GROWTH AND BEHAVIOR OF LARVAL ZEBRAFISH Danio ...

    EPA Pesticide Factsheets

    Because Zebrafish (Danio rerio) have become a popular and important model for scientific research, the capability to rear larval zebrafish to adulthood is of great importance. Recently research examining the effects of diet (live versus processed) have been published. In the current study we examined whether the larvae can be reared on a processed diet alone, live food alone, or the combination while maintaining normal locomotor behavior, and acceptable survival, length and weight at 14 dpf in a static system. A 14 day feeding trial was conducted in glass crystallizing dishes containing 500 ml of 4 ppt Instant Ocean. On day 0 pdf 450 embryos were selected as potential study subjects and placed in a 26○C incubator on a 14:10 (light:dark) light cycle. At 4 dpf 120 normally developing embryos were selected per treatment and divided into 3 bowls of 40 embryos (for an n=3 per treatment; 9 bowls total). Treatment groups were: G (Gemma Micro 75 only), R (L-type marine rotifers (Brachionus plicatilis) only) or B (Gemma and rotifers). Growth (length), survival, water quality and rotifer density were monitored on days 5-14. On day 14, weight of larva in each bowl was measured and 8 larva per bowl were selected for use in locomotor testing. This behavior paradigm tests individual larval zebrafish under both light and dark conditions in a 24-well plate.After 14 dpf, survival among the groups was not different (92-98%). By days 7 -14 R and B larvae were ~2X longer

  4. Larval traits carry over to affect post-settlement behaviour in a common coral reef fish.

    PubMed

    Dingeldein, Andrea L; White, J Wilson

    2016-07-01

    Most reef fishes begin life as planktonic larvae before settling to the reef, metamorphosing and entering the benthic adult population. Different selective forces determine survival in the planktonic and benthic life stages, but traits established in the larval stage may carry over to affect post-settlement performance. We tested the hypothesis that larval traits affect two key post-settlement fish behaviours: social group-joining and foraging. Certain larval traits of reef fishes are permanently recorded in the rings in their otoliths. In the bluehead wrasse (Thalassoma bifasciatum), prior work has shown that key larval traits recorded in otoliths (growth rate, energetic condition at settlement) carry over to affect post-settlement survival on the reef, with higher-larval-condition fish experiencing less post-settlement mortality. We hypothesized that this selective mortality is mediated by carry-over effects on post-settlement antipredator behaviours. We predicted that better-condition fish would forage less and be more likely to join groups, both behaviours that would reduce predation risk. We collected 550 recently settled bluehead wrasse (Thalassoma bifasciatum) from three reef sites off St. Croix (USVI) and performed two analyses. First, we compared each settler's larval traits to the size of its social group to determine whether larval traits influenced group-joining behaviour. Secondly, we observed foraging behaviour in a subset of grouped and solitary fish (n = 14) for 1-4 days post-settlement. We then collected the fish and tested whether larval traits influenced the proportion of time spent foraging. Body length at settlement, but not condition, affected group-joining behaviour; smaller fish were more likely to remain solitary or in smaller groups. However, both greater length and better condition were associated with greater proportions of time spent foraging over four consecutive days post-settlement. Larval traits carry over to affect post

  5. Silencing of ecdysone receptor, insect intestinal mucin and sericotropin genes by bacterially produced double-stranded RNA affects larval growth and development in Plutella xylostella and Helicoverpa armigera.

    PubMed

    Israni, B; Rajam, M V

    2017-04-01

    RNA interference mediated gene silencing, which is triggered by double-stranded RNA (dsRNA), has become a important tool for functional genomics studies in various systems, including insects. Bacterially produced dsRNA employs the use of a bacterial strain lacking in RNaseIII activity and harbouring a vector with dual T7 promoter sites, which allow the production of intact dsRNA molecules. Here, we report an assessment of the functional relevance of the ecdysone receptor, insect intestinal mucin and sericotropin genes through silencing by dsRNA in two lepidopteran insect pests, Helicoverpa armigera and Plutella xylostella, both of which cause serious crop losses. Oral feeding of dsRNA led to significant reduction in transcripts of the target insect genes, which caused significant larval mortality with various moulting anomalies and an overall developmental delay. We also found a significant decrease in reproductive potential in female moths, with a drop in egg laying and compromised egg hatching from treated larvae as compared to controls. dsRNA was stable in the insect gut and was efficiently processed into small interfering RNAs (siRNAs), thus accounting for the phenotypes observed in the present work. The study revealed the importance of these genes in core insect processes, which are essential for insect development and survival.

  6. Development of the larval amphibian growth and development ...

    EPA Pesticide Factsheets

    The Larval Amphibian Growth and Development Assay (LAGDA) is a Tier II test guideline being developed by the US Environmental Protection Agency under the Endocrine Disruptor Screening Program. The LAGDA was designed to evaluate effects of chronic chemical exposure on growth, thyroid-mediated amphibian metamorphosis and reproductive development. To evaluate the assay’s performance, two model chemicals targeting the hypothalamic-pituitary-gonadal (HPG) axis were tested; a weak estrogen receptor agonist, 4-tert-octylphenol (tOP), and an androgen receptor agonist, 17β-trenbolone (TB). Xenopus laevis embryos were constantly exposed in flow-through conditions to various test concentrations of tOP (nominal: 6.25, 12.5, 25, 50 μg/L) or TB (nominal: 12.5, 25, 50, 100 ng/L) and clean water controls until 8 weeks post-metamorphosis, at which time growth measurements were taken and histopathology assessments were made on gonads, reproductive ducts, liver and kidneys. There were no effects on growth in either study and no signs of overt toxicity, sex reversal or gonad dysgenesis at the concentrations tested. Exposure to tOP caused a treatment-related decrease in circulating thyroxine and an increase in thyroid follicular cell hypertrophy and hyperplasia (25, 50 μg/L). Müllerian duct development was clearly affected following exposure to both chemicals; tOP exposure caused dose-dependent maturation of oviducts in both male and female frogs, whereas TB exposure ca

  7. Impacts of a gape limited Brook Trout, Salvelinus fontinalis, on larval Northwestern salamander, Ambystoma gracile, growth: A field enclosure experiment

    USGS Publications Warehouse

    Currens, C.R.; Liss, W.J.; Hoffman, R.L.

    2007-01-01

    The formation of amphibian population structure is directly affected by predation. Although aquatic predators have been shown to have direct negative effects on larval salamanders in laboratory and field experiments, the potential impacts of gape-limited fish on larval salamander growth has been largely underexplored. We designed an enclosure experiment conducted in situ to quantify the effects of gape-limited Brook Trout (Salvelinus fontinalis) on larval Northwestern Salamander (Ambystoma gracile) growth. We specifically tested whether the presence of fish too small to consume larvae had a negative effect on larval growth. The results of this study indicate that the presence of a gape-limited S. fontinalis can have a negative effect on growth of larval A. gracile salamanders. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  8. Maternal cortisol stimulates neurogenesis and affects larval behaviour in zebrafish

    PubMed Central

    Best, Carol; Kurrasch, Deborah M.; Vijayan, Mathilakath M.

    2017-01-01

    Excess glucocorticoid transferred from stressed mother to the embryo affects developing vertebrate offspring, but the underlying programming events are unclear. In this study, we tested the hypothesis that increased zygotic glucocorticoid deposition, mimicking a maternal stress scenario, modifies early brain development and larval behaviour in zebrafish (Danio rerio). Cortisol was microinjected into the yolk at one cell-stage, to mimic maternal transfer, and the larvae [96 hours post-fertilization (hpf)] displayed increased activity in light and a reduction in thigmotaxis, a behavioural model for anxiety, suggesting an increased propensity for boldness. This cortisol-mediated behavioural phenotype corresponded with an increase in primary neurogenesis, as measured by incorporation of EdU at 24 hpf, in a region-specific manner in the preoptic region and the pallium, the teleostean homolog of the hippocampus. Also, cortisol increased the expression of the proneural gene neurod4, a marker of neurogenesis, in a region- and development-specific manner in the embryos. Altogether, excess zygotic cortisol, mimicking maternal stress, affects early brain development and behavioural phenotype in larval zebrafish. We propose a key role for cortisol in altering brain development leading to enhanced boldness, which may be beneficial in preparing the offspring to a stressful environment and enhancing fitness. PMID:28098234

  9. Elevated major ion concentrations inhibit larval mayfly growth and development.

    PubMed

    Johnson, Brent R; Weaver, Paul C; Nietch, Christopher T; Lazorchak, James M; Struewing, Katherine A; Funk, David H

    2015-01-01

    Anthropogenic disturbances, including those from developing energy resources, can alter stream chemistry significantly by elevating total dissolved solids. Field studies have indicated that mayflies (Order Ephemeroptera) are particularly sensitive to high total dissolved solids. In the present study, the authors measured 20-d growth and survivorship of larval Neocloeon triangulifer exposed to a gradient of brine salt (mixed NaCl and CaCl2 ) concentrations. Daily growth rates were reduced significantly in all salt concentrations above the control (363 µS cm(-1) ) and larvae in treatments with specific conductance >812 µS cm(-1) were in comparatively earlier developmental stages (instars) at the end of the experiment. Survivorship declined significantly when specific conductance was >1513 µS cm(-1) and the calculated 20-d 50% lethal concentration was 2866 µS cm(-1) . The present study's results provide strong experimental evidence that elevated ion concentrations similar to those observed in developing energy resources, such as oil and gas drilling or coal mining, can adversely affect sensitive aquatic insect species.

  10. Factors affecting bone growth.

    PubMed

    Gkiatas, Ioannis; Lykissas, Marios; Kostas-Agnantis, Ioannis; Korompilias, Anastasios; Batistatou, Anna; Beris, Alexandros

    2015-02-01

    Bone growth and development are products of the complex interactions of genetic and environmental factors. Longitudinal bone growth depends on the growth plate. The growth plate has 5 different zones-each with a different functional role-and is the final target organ for longitudinal growth. Bone length is affected by several systemic, local, and mechanical factors. All these regulation systems control the final length of bones in a complicated way. Despite its significance to bone stability, bone growth in width has not been studied as extensively as longitudinal bone growth. Bone growth in width is also controlled by genetic factors, but mechanical loading regulates periosteal apposition. In this article, we review the most recent data regarding bone growth from the embryonic age and analyze the factors that control bone growth. An understanding of this complex system is important in identifying metabolic and developmental bone diseases and fracture risk.

  11. Larval diet affects mosquito development and permissiveness to Plasmodium infection

    PubMed Central

    Linenberg, Inbar; Christophides, George K.; Gendrin, Mathilde

    2016-01-01

    The larval stages of malaria vector mosquitoes develop in water pools, feeding mostly on microorganisms and environmental detritus. Richness in the nutrient supply to larvae influences the development and metabolism of larvae and adults. Here, we investigated the effects of larval diet on the development, microbiota content and permissiveness to Plasmodium of Anopheles coluzzii. We tested three fish diets often used to rear mosquitoes in the laboratory, including two pelleted diets, Dr. Clarke’s Pool Pellets and Nishikoi Fish Pellets, and one flaked diet, Tetramin Fish-Flakes. Larvae grow and develop faster and produce bigger adults when feeding on both types of pellets compared with flakes. This correlates with a higher microbiota load in pellet-fed larvae, in agreement with the known positive effect of the microbiota on mosquito development. Larval diet also significantly influences the prevalence and intensity of Plasmodium berghei infection in adults, whereby Nishikoi Fish Pellets-fed larvae develop into adults that are highly permissive to parasites and survive longer after infection. This correlates with a lower amount of Enterobacteriaceae in the midgut microbiota. Together, our results shed light on the influence of larval feeding on mosquito development, microbiota and vector competence; they also provide useful data for mosquito rearing. PMID:27910908

  12. Larval growth rate and sex determine resource allocation and stress responsiveness across life stages in juvenile frogs.

    PubMed

    Warne, Robin W; Crespi, Erica J

    2015-03-01

    The extent to which interactions between environmental stressors and phenotypic variation during larval life stages impose carry-over effects on adult phenotypes in wildlife are not clear. Using semi-natural mesocosms, we examined how chronically low food availability and size-specific phenotypes in larval amphibians interact and carry over to influence frog growth, resource allocation, endocrine activity and survival. We tagged three cohorts of larvae that differed in body size and developmental stage at 3 weeks after hatching, and tracked them through 10 weeks after metamorphosis in high and low food conditions. We found that growth and development rates during the early tadpole stage not only affected metamorphic rates, but also shaped resource allocation and stress responsiveness in frogs: the slowest growing larvae from low-food mesocosms exhibited a suppressed glucocorticoid response to a handling stressor; reduced growth rate and fat storage as frogs. We also show for the first time that larval developmental trajectories varied with sex, where females developed faster than males especially in food-restricted conditions. Last, while larval food restriction profoundly affected body size in larvae and frogs, time to metamorphosis was highly constrained, which suggests that the physiology and development of this ephemeral pond-breeding amphibian is adapted for rapid metamorphosis despite large potential variation in nutrient availability. Taken together, these results suggest that larval phenotypic variation significantly influences multiple dimensions of post-metamorphic physiology and resource allocation, which likely affect overall performance.

  13. Development of the larval amphibian growth and development ...

    EPA Pesticide Factsheets

    The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized chemical testing guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan’s Ministry of Environment to support risk assessment. The assay is employed as a higher tiered approach to evaluate effects of chronic chemical exposure throughout multiple life stages in model amphibian species Xenopus laevis. To evaluate the utility of the initial LAGDA design, the assay was performed using a mixed mode of action endocrine disrupting chemical, benzophenone-2 (BP-2). X. laevis embryos were exposed in flow-through conditions to 0, 1.5, 3.0 or 6.0 mg/L BP-2 until two months post-metamorphosis. Overt toxicity was evident throughout the exposure period in the 6.0 mg/L treatment due to elevated mortality rates and observed liver and kidney pathologies. Concentration-dependent increases in severity of thyroid follicular cell hypertrophy and hyperplasia occurred in larval tadpoles indicating BP-2-induced impacts on the thyroid axis. Additionally, gonads were impacted in all treatments with some genotypic males showing both testis and ovary tissues (1.5 mg/L) and 100% of the genotypic males in the higher treatments (3.0 and 6.0 mg/L) experiencing complete male-to-female sex reversal. Concentration-dependent vitellogenin (Vtg) induction occurred in both genders with associated accumulations of protein in the livers, kidneys and gonads, which was likely Vtg

  14. A genetic screen for zebrafish mutants with hepatic steatosis identifies a locus required for larval growth.

    PubMed

    Hugo, Sarah E; Schlegel, Amnon

    2017-03-01

    In a screen for zebrafish larval mutants with excessive liver lipid accumulation (hepatic steatosis), we identified harvest moon (hmn). Cytoplasmic lipid droplets, surrounded by multivesicular structures and mitochondria whose cristae appeared swollen, are seen in hmn mutant hepatocytes. Whole body triacylglycerol is increased in hmn mutant larvae. When we attempted to raise mutants, which were morphologically normal at the developmental stage that the screen was conducted, to adulthood, we observed that most hmn mutants do not survive to the juvenile period when raised. An arrest in growth occurs in the late larval period without obvious organ defects. Maternal zygotic mutants have no additional defects, suggesting that the mutation affects a late developmental process. The developmental window between embryogenesis and the metamorphosis remains under-studied, and hmn mutants might be useful for exploring the molecular and anatomic processes occurring during this transition period.

  15. Biomechanics of larval morphology affect swimming: insights from the sand dollars Dendraster excentricus.

    PubMed

    Chan, Kit Yu Karen

    2012-10-01

    Most planktonic larvae of marine invertebrates are denser than sea water, and rely on swimming to locate food, navigate advective currents, and avoid predators. Therefore, swimming behaviors play important roles in larval survival and dispersal. Larval bodies are often complex and highly variable across developmental stages and environmental conditions. These complex morphologies reflect compromises among multiple evolutionary pressures, including maintaining the ability to swim. Here, I highlight metrics of swimming performance, their relationships with morphology, and the roles of behavior in modulating larval swimming within biomechanical limits. Sand dollars have a representative larval morphology using long ciliated projections for swimming and feeding. Observed larval sand dollars fell within a narrow range of key morphological parameters that maximized their abilities to maintain directed upward movement over the most diverse flow fields, outperforming hypothetical alternatives in a numerical model. Ontogenetic changes in larval morphology also led to different vertical movements in simulated flow fields, implying stage-dependent vertical distributions and lateral transport. These model outcomes suggest a tight coupling between larval morphology and swimming. Environmental stressors, such as changes in temperature and pH, can therefore affect larval swimming through short-term behavioral adjustments and long-term changes in morphology. Larval sand dollars reared under elevated pCO(2) conditions had significantly different morphology, but not swimming speeds or trajectories. Geometric morphometric analysis showed a pH-dependent, size-mediated change in shape, suggesting a coordinated morphological adjustment to maintain swimming performance under acidified conditions. Quantification of the biomechanics and behavioral aspects of swimming improves predictions of larval survival and dispersal under present-day and future environmental conditions.

  16. Rising CO2 concentrations affect settlement behaviour of larval damselfishes

    NASA Astrophysics Data System (ADS)

    Devine, B. M.; Munday, P. L.; Jones, G. P.

    2012-03-01

    Reef fish larvae actively select preferred benthic habitat, relying on olfactory, visual and acoustic cues to discriminate between microhabitats at settlement. Recent studies show exposure to elevated carbon dioxide (CO2) impairs olfactory cue recognition in larval reef fishes. However, whether this alters the behaviour of settling fish or disrupts habitat selection is unknown. Here, the effect of elevated CO2 on larval behaviour and habitat selection at settlement was tested in three species of damselfishes (family Pomacentridae) that differ in their pattern of habitat use: Pomacentrus amboinensis (a habitat generalist), Pomacentrus chrysurus (a rubble specialist) and Pomacentrus moluccensis (a live coral specialist). Settlement-stage larvae were exposed to current-day CO2 levels or CO2 concentrations that could occur by 2100 (700 and 850 ppm) based on IPCC emission scenarios. First, pair-wise choice tests were performed using a two-channel flume chamber to test olfactory discrimination between hard coral, soft coral and coral rubble habitats. The habitat selected by settling fish was then compared among treatments using a multi-choice settlement experiment conducted overnight. Finally, settlement timing between treatments was compared across two lunar cycles for one of the species, P. chrysurus. Exposure to elevated CO2 disrupted the ability of larvae to discriminate between habitat odours in olfactory trials. However, this had no effect on the habitats selected at settlement when all sensory cues were available. The timing of settlement was dramatically altered by CO2 exposure, with control fish exhibiting peak settlement around the new moon, whereas fish exposed to 850 ppm CO2 displaying highest settlement rates around the full moon. These results suggest larvae can rely on other sensory information, such as visual cues, to compensate for impaired olfactory ability when selecting settlement habitat at small spatial scales. However, rising CO2 could cause larvae

  17. Growth and mortality of larval Myctophum affine (Myctophidae, Teleostei).

    PubMed

    Namiki, C; Katsuragawa, M; Zani-Teixeira, M L

    2015-04-01

    The growth and mortality rates of Myctophum affine larvae were analysed based on samples collected during the austral summer and winter of 2002 from south-eastern Brazilian waters. The larvae ranged in size from 2·75 to 14·00 mm standard length (L(S)). Daily increment counts from 82 sagittal otoliths showed that the age of M. affine ranged from 2 to 28 days. Three models were applied to estimate the growth rate: linear regression, exponential model and Laird-Gompertz model. The exponential model best fitted the data, and L(0) values from exponential and Laird-Gompertz models were close to the smallest larva reported in the literature (c. 2·5 mm L(S)). The average growth rate (0·33 mm day(-1)) was intermediate among lanternfishes. The mortality rate (12%) during the larval period was below average compared with other marine fish species but similar to some epipelagic fishes that occur in the area.

  18. Larval growth of Diaprepes abbreviatus (Coleoptera: Curculionidae) and resulting root injury to three citrus varieties in two soil types.

    PubMed

    Rogers, S; Mccoy, C W; Graham, J H

    2000-04-01

    Larval growth and intraspecific competition of Diaprepes abbreviatus (L.) larvae and consequent root injury in container-grown citrus in the greenhouse were evaluated. Roots of Carrizo citrange, Citrus sinesis L. Osbeck x Poncirus trifoliata (L.) Raf.; Cleopatra mandarin, C. reticulata Blanco, and Swingle citrumelo, C. paradisi Macf. x P. trifoliata (L.) Raf. rootstock seedlings grown in Candler fine sand and potting soil were colonized with different populations of D. abbreviatus larvae. Larvae were exposed to the seedlings for 79 d. Larval growth and development increased steadily for approximately 70 d on all rootstock-soil combinations, at which time most larvae were instars 6-8. Most feeding injury occurred to roots when larvae were between instars 3 and 6. Larval weight reached a plateau at approximately 70 d, but often declined between 70 and 79 d. When larvae were small, injury to seedlings developed slowly, primarily on fibrous roots, then feeding increased rapidly, often resulting in total consumption of both fibrous root and bark tissue. Although not statistically significant, root injury developed slightly slower on Swingle citrumelo compared with Carrizo and Cleopatra rootstocks, but damage was comparable by 79 d. Little or no difference in consumptive benefit to the larvae was found between the rootstocks. Based on larval weight days, little feeding injury occurred during the first 21 d, but increased rapidly between 21 and 60 d. Soil type affected the rate of larval growth and development, with potting soil contributing to greater growth rates. Detritus in potting soil provided little or no nutritional resource, suggesting that the effect of potting soil on larval development was primarily physical. In addition, fewer inoculated larvae per seedling exhibited greater weight gains than higher infestation densities, suggesting that intraspecific competition for nutritional resources influenced larval development.

  19. Laboratory studies on larval growth of Polydora ligni, Polydora ciliata, and Pygospio elegans (Polychaeta, Spionidae)

    NASA Astrophysics Data System (ADS)

    Anger, K.; Anger, V.; Hagmeier, E.

    1986-12-01

    The spionid polychaete species Polydora ligni, P. ciliata, and Pygospio elegans were cultivated in the laboratory over several successive generations. A flow-through cultivation system for Polydora spp. is described. Duration of life cycles (time from hatching of the larva to first reproduction) and life spans (hatching to death) of these species were not significantly influenced by the degree of inbreeding nor by individual age of the parents. Minimum time from metamorphosis (15-setiger stage) to first hatching of offspring larvae (in the 3-setiger stage) at 18°C was 33 days in Polydora spp. and 81 days in Pygospio elegans. Larval growth patterns are described in terms of number of setigers, body length, and biomass (dry weight, carbon, nitrogen, hydrogen), in relation to time after hatching. Regression models are proposed which link these measures of larval growth and, thus, may be used for conversions. Rates of development and growth show a high degree of variability in all three species, not only caused by variation in environmental factors such as temperature or food, but also among and within single hatches of larvae reared under identical conditions. Larvae were reared at constant temperatures (6°, 12°, and 18°C). Temperature affected larval growth in Polydora ligni more than in P. ciliata, and least of all in Pygospio elegans. Only the latter species was able to develop at 6°C from hatching to metamorphosis. This differential response may be explained by differences in the natural spawning season of these species. Eleven phytoplankton species were tested as to their food values. A “relative index of growth” is proposed which compares the slopes of two growth curves (one standard and one test condition). The flagellate Dunaliella tertiolecta was used as a standard food in these experiments. Most algal species were less suitable, and only the diatom Thalassiosira rotula was consistently better food for spionid larvae than D. tertiolecta.

  20. Larval nutritional stress affects vector life history traits and human malaria transmission

    PubMed Central

    Vantaux, Amélie; Lefèvre, Thierry; Cohuet, Anna; Dabiré, Kounbobr Roch; Roche, Benjamin; Roux, Olivier

    2016-01-01

    Exposure to stress during an insect’s larval development can have carry-over effects on adult life history traits and susceptibility to pathogens. We investigated the effects of larval nutritional stress for the first time using field mosquito vectors and malaria parasites. In contrast to previous studies, we show that larval nutritional stress may affect human to mosquito transmission antagonistically: nutritionally deprived larvae showed lower parasite prevalence for only one gametocyte carrier; they also had lower fecundity. However, they had greater survival rates that were even higher when infected. When combining these opposing effects into epidemiological models, we show that larval nutritional stress induced a decrease in malaria transmission at low mosquito densities and an increase in transmission at high mosquito densities, whereas transmission by mosquitoes from well-fed larvae was stable. Our work underscores the importance of including environmental stressors towards understanding host–parasite dynamics to improve disease transmission models and control. PMID:27827429

  1. Larval nutritional stress affects vector life history traits and human malaria transmission.

    PubMed

    Vantaux, Amélie; Lefèvre, Thierry; Cohuet, Anna; Dabiré, Kounbobr Roch; Roche, Benjamin; Roux, Olivier

    2016-11-09

    Exposure to stress during an insect's larval development can have carry-over effects on adult life history traits and susceptibility to pathogens. We investigated the effects of larval nutritional stress for the first time using field mosquito vectors and malaria parasites. In contrast to previous studies, we show that larval nutritional stress may affect human to mosquito transmission antagonistically: nutritionally deprived larvae showed lower parasite prevalence for only one gametocyte carrier; they also had lower fecundity. However, they had greater survival rates that were even higher when infected. When combining these opposing effects into epidemiological models, we show that larval nutritional stress induced a decrease in malaria transmission at low mosquito densities and an increase in transmission at high mosquito densities, whereas transmission by mosquitoes from well-fed larvae was stable. Our work underscores the importance of including environmental stressors towards understanding host-parasite dynamics to improve disease transmission models and control.

  2. The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees.

    PubMed

    Helm, Bryan R; Slater, Garett; Rajamohan, Arun; Yocum, George D; Greenlee, Kendra J; Bowsher, Julia H

    2017-04-10

    In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diets are often complex and may interact with one another, necessitating the use of a geometric framework for elucidating nutritional effects. In the honey bee, Apis mellifera, nurse bees provision food to developing larvae, directly moderating growth rates and caste development. However, the eusocial nature of honey bees makes nutritional studies challenging, because diet components cannot be systematically manipulated in the hive. Using in vitro rearing, we investigated the roles and interactions between carbohydrate and protein content on larval survival, growth, and development in A. mellifera We applied a geometric framework to determine how these two nutritional components interact across nine artificial diets. Honey bees successfully completed larval development under a wide range of protein and carbohydrate contents, with the medium protein (∼5%) diet having the highest survival. Protein and carbohydrate both had significant and non-linear effects on growth rate, with the highest growth rates observed on a medium-protein, low-carbohydrate diet. Diet composition did not have a statistically significant effect on development time. These results confirm previous findings that protein and carbohydrate content affect the growth of A. mellifera larvae. However, this study identified an interaction between carbohydrate and protein content that indicates a low-protein, high-carb diet has a negative effect on larval growth and survival. These results imply that worker recruitment in the hive would decline under low protein conditions, even when nectar abundance or honey stores are sufficient.

  3. Response of larval Xenopus laevis to atrazine: assessment of growth, metamorphosis, and gonadal and laryngeal morphology.

    PubMed

    Carr, James A; Gentles, Angie; Smith, Ernest E; Goleman, Wanda L; Urquidi, Lina J; Thuett, Kerry; Kendall, Ronald J; Giesy, John P; Gross, Tim S; Solomon, Keith R; Van Der Kraak, Glen

    2003-02-01

    Larval Xenopus laevis were exposed to one of four concentrations of atrazine (0, 1, 10, or 25 microg/L, 11 replicate tanks per treatment, 60-65 larvae per replicate) dissolved in an artificial pond water (frog embryo teratogenesis assay- Xenopus [FETAX]) medium beginning 48 h after hatching until the completion of metamorphosis. Separate groups of larvae (six replicate tanks per treatment, 60-65 larvae per replicate) were exposed to estradiol (100 microg/L), dihydrotestosterone (100 microg/L), or ethanol vehicle control dissolved in FETAX medium. None of the treatments affected posthatch mortality, larval growth, or metamorphosis. There were no treatment effects on sex ratios except for estradiol, which produced a greater percentage of female offspring. Exposure to either estradiol or 25 microg atrazine/L increased the incidence of intersex animals based on assessment of gonadal morphology. Atrazine did not reduce the size of the laryngeal dilator muscle, a sexually dimorphic muscle in this species. We conclude that environmentally relevant concentrations of atrazine do not influence metamorphosis or sex ratios and do not inhibit sexually dimorphic larynx growth in X. laevis. The incidence of atrazine-induced intersex animals was small (<5%) and occurred only at the greatest concentration of atrazine tested, a concentration that is rarely observed in surface waters in the United States.

  4. Larval nutritional stress affects vector immune traits in adult yellow fever mosquito Aedes aegypti (Stegomyia aegypti).

    PubMed

    Telang, A; Qayum, A A; Parker, A; Sacchetta, B R; Byrnes, G R

    2012-09-01

    We report key physiological traits that link larval nutritional experience to adult immune status in the yellow fever mosquito Aedes aegypti L. (Stegomyia aegypti) (Diptera: Culicidae). Many lines of defence make up the innate immune system of mosquitoes. Among defences, the epithelium-lined midgut is the first barrier, circulating haemocytes are cellular components of innate immunity and, when triggered, the Toll and Imd pathways signal production of antimicrobial peptides (AMP) as part of humoral defences. We quantified three lines of defence in Ae. aegypti in response to larval nutritional stress, and our data show that important female immune functions are modified by the larval rearing environment. Adult midgut basal lamina thickness was not affected by larval nutrient stress as has been observed in another Aedes sp. However, nutrient stresses experienced by larvae lead to a reduced number of haemocytes in females. Transcripts of Spaetzle (upstream regulator of Toll pathway that leads to induction of AMPs) and some immune-related genes were less abundant in stressed larvae but showed increased expression in females derived from stressed larvae. Results indicate a potential for compensation by the humoral branch for a reduced cellular branch of innate immunity in adults in response to larval nutrient stress.

  5. Larval food quantity affects the capacity of adult mosquitoes to transmit human malaria

    PubMed Central

    Shapiro, Lillian L. M.; Murdock, Courtney C.; Jacobs, Gregory R.; Thomas, Rachel J.; Thomas, Matthew B.

    2016-01-01

    Adult traits of holometabolous insects are shaped by conditions experienced during larval development, which might impact interactions between adult insect hosts and parasites. However, the ecology of larval insects that vector disease remains poorly understood. Here, we used Anopheles stephensi mosquitoes and the human malaria parasite Plasmodium falciparum, to investigate whether larval conditions affect the capacity of adult mosquitoes to transmit malaria. We reared larvae in two groups; one group received a standard laboratory rearing diet, whereas the other received a reduced diet. Emerging adult females were then provided an infectious blood meal. We assessed mosquito longevity, parasite development rate and prevalence of infectious mosquitoes over time. Reduced larval food led to increased adult mortality and caused a delay in parasite development and a slowing in the rate at which parasites invaded the mosquito salivary glands, extending the time it took for mosquitoes to become infectious. Together, these effects increased transmission potential of mosquitoes in the high food regime by 260–330%. Such effects have not, to our knowledge, been shown previously for human malaria and highlight the importance of improving knowledge of larval ecology to better understand vector-borne disease transmission dynamics. PMID:27412284

  6. Triterpene acids from apple peel inhibit lepidopteran larval midgut lipases and larval growth.

    PubMed

    Christeller, John T; McGhie, Tony K; Poulton, Joanne; Markwick, Ngaire P

    2014-07-01

    Fruit extracts from apple, kiwifruit, feijoa, boysenberry, and blueberry were screened for the presence of lipase inhibitory compounds against lepidopteran larval midgut crude extracts. From 120 extracts, six showed significant inhibition with an extract from the peel of Malus × domestica cv. "Big Red" showing highest levels of inhibition. Because this sample was the only apple peel sample in the initial screen, a survey of peels from seven apple cultivars was undertaken and showed that, despite considerable variation, all had inhibitory activity. Successive solvent fractionation and LC-MS of cv. "Big Red" apple peel extract identified triterpene acids as the most important inhibitory compounds, of which ursolic acid and oleanolic acid were the major components and oxo- and hydroxyl-triterpene acids were minor components. When ursolic acid was incorporated into artificial diet and fed to Epiphyas postvittana Walker (Tortricidae: Lepidoptera) larvae at 0.16% w/v, a significant decrease in larval weight was observed after 21 days. This concentration of ursolic acid is less than half the concentration reported in the skin of some apple cultivars.

  7. Aedes aegypti pharate 1st instar quiescence affects larval fitness and metal tolerance.

    PubMed

    Perez, Mario H; Noriega, Fernando G

    2012-06-01

    The eggs of the mosquito Aedes aegypti possess the ability to undergo an extended quiescence hosting a fully developed 1st instar larvae within the chorion. As a result of this life history trait pharate larvae can withstand months of quiescence inside the egg where they depend on stored maternal reserves. A. aegypti mosquitoes are frequently associated with urban habitats that may contain significant metal pollution. Therefore, the duration of quiescence and extent of nutritional depletion may affect the physiology and survival of larvae that hatch in a suboptimal habitat. The aim of this study was to determine the effect of an extended quiescence on larval nutrient reserves and the subsequent effects of metal exposure on larval fitness, survival and development. We hypothesized that an extended quiescence would reduce nutritional reserves and alter the molecular response to metal exposure thereby reducing larval survival and altering larval development. As a molecular marker for metal stress responses, we evaluated transcriptional changes in the metallothionein gene (AaMtn) in response to quiescence and metal exposure. Extended 1st instar quiescence resulted in a significant decrease in lipid reserves and negatively affected larval fitness and development. AaMtn transcription and metal tolerance were compromised in first instars emerged from eggs that had undergone an extended quiescence. These findings suggest that newly emerged mosquito larvae that had survived a relatively long pharate 1st instar quiescence (as might occur during a dry season) are more vulnerable to environmental stress. Pharate 1st instar quiescence could have implications for vector control strategies. Newly emerged mosquito larvae at the end of the dry season or start of the wet season are physiologically compromised, and therefore potentially more susceptible to vector control strategies than mosquito larvae hatched subsequently throughout the wet season.

  8. Fast versus slow larval growth in an invasive marine mollusc: does paternity matter?

    PubMed

    Le Cam, Sabrina; Pechenik, Jan A; Cagnon, Mathilde; Viard, Frédérique

    2009-01-01

    Reproductive strategies and parental effects play a major role in shaping early life-history traits. Although polyandry is a common reproductive strategy, its role is still poorly documented in relation to paternal effects. Here, we used as a case study the invasive sessile marine gastropod Crepidula fornicata, a mollusc with polyandry and extreme larval growth variation among sibling larvae. Based on paternity analyses, the relationships between paternal identity and the variations in a major early life-history trait in marine organisms, that is, larval growth, were investigated. Using microsatellite markers, paternities of 437 fast- and slow-growing larvae from 6 broods were reliably assigned to a set of 20 fathers. No particular fathers were found responsible for the specific growth performances of their offspring. However, the range of larval growth rates within a brood was significantly correlated to 1) an index of sire diversity and 2) the degree of larvae relatedness within broods. Multiple paternity could thus play an important role in determining the extent of pelagic larval duration and consequently the range of dispersal distances achieved during larval life. This study also highlighted the usefulness of using indices based on fathers' relative contribution to the progeny in paternity studies.

  9. Maintained larval growth in mussel larvae exposed to acidified under-saturated seawater

    NASA Astrophysics Data System (ADS)

    Ventura, Alexander; Schulz, Sabrina; Dupont, Sam

    2016-03-01

    Ocean acidification (OA) is known to affect bivalve early life-stages. We tested responses of blue mussel larvae to a wide range of pH in order to identify their tolerance threshold. Our results confirmed that decreasing seawater pH and decreasing saturation state increases larval mortality rate and the percentage of abnormally developing larvae. Virtually no larvae reared at average pHT 7.16 were able to feed or reach the D-shell stage and their development appeared to be arrested at the trochophore stage. However larvae were capable of reaching the D-shell stage under milder acidification (pHT ≈ 7.35, 7.6, 7.85) including in under-saturated seawater with Ωa as low as 0.54 ± 0.01 (mean ± s. e. m.), with a tipping point for normal development identified at pHT 7.765. Additionally growth rate of normally developing larvae was not affected by lower pHT despite potential increased energy costs associated with compensatory calcification in response to increased shell dissolution. Overall, our results on OA impacts on mussel larvae suggest an average pHT of 7.16 is beyond their physiological tolerance threshold and indicate a shift in energy allocation towards growth in some individuals revealing potential OA resilience.

  10. Maintained larval growth in mussel larvae exposed to acidified under-saturated seawater.

    PubMed

    Ventura, Alexander; Schulz, Sabrina; Dupont, Sam

    2016-03-29

    Ocean acidification (OA) is known to affect bivalve early life-stages. We tested responses of blue mussel larvae to a wide range of pH in order to identify their tolerance threshold. Our results confirmed that decreasing seawater pH and decreasing saturation state increases larval mortality rate and the percentage of abnormally developing larvae. Virtually no larvae reared at average pHT 7.16 were able to feed or reach the D-shell stage and their development appeared to be arrested at the trochophore stage. However larvae were capable of reaching the D-shell stage under milder acidification (pHT ≈ 7.35, 7.6, 7.85) including in under-saturated seawater with Ωa as low as 0.54 ± 0.01 (mean ± s. e. m.), with a tipping point for normal development identified at pHT 7.765. Additionally growth rate of normally developing larvae was not affected by lower pHT despite potential increased energy costs associated with compensatory calcification in response to increased shell dissolution. Overall, our results on OA impacts on mussel larvae suggest an average pHT of 7.16 is beyond their physiological tolerance threshold and indicate a shift in energy allocation towards growth in some individuals revealing potential OA resilience.

  11. Maintained larval growth in mussel larvae exposed to acidified under-saturated seawater

    PubMed Central

    Ventura, Alexander; Schulz, Sabrina; Dupont, Sam

    2016-01-01

    Ocean acidification (OA) is known to affect bivalve early life-stages. We tested responses of blue mussel larvae to a wide range of pH in order to identify their tolerance threshold. Our results confirmed that decreasing seawater pH and decreasing saturation state increases larval mortality rate and the percentage of abnormally developing larvae. Virtually no larvae reared at average pHT 7.16 were able to feed or reach the D-shell stage and their development appeared to be arrested at the trochophore stage. However larvae were capable of reaching the D-shell stage under milder acidification (pHT ≈ 7.35, 7.6, 7.85) including in under-saturated seawater with Ωa as low as 0.54 ± 0.01 (mean ± s. e. m.), with a tipping point for normal development identified at pHT 7.765. Additionally growth rate of normally developing larvae was not affected by lower pHT despite potential increased energy costs associated with compensatory calcification in response to increased shell dissolution. Overall, our results on OA impacts on mussel larvae suggest an average pHT of 7.16 is beyond their physiological tolerance threshold and indicate a shift in energy allocation towards growth in some individuals revealing potential OA resilience. PMID:27020613

  12. Unravelling the Gordian knot! Key processes impacting overwintering larval survival and growth: A North Sea herring case study

    NASA Astrophysics Data System (ADS)

    Hufnagl, Marc; Peck, Myron A.; Nash, Richard D. M.; Dickey-Collas, Mark

    2015-11-01

    Unraveling the key processes affecting marine fish recruitment will ultimately require a combination of field, laboratory and modelling studies. We combined analyzes of long-term (30-year) field data on larval fish abundance, distribution and length, and biophysical model simulations of different levels of complexity to identify processes impacting the survival and growth of autumn- and winter-spawned Atlantic herring (Clupea harengus) larvae. Field survey data revealed interannual changes in intensity of utilization of the five major spawning grounds (Orkney/Shetland, Buchan, Banks north, Banks south, and Downs) as well as spatio-temporal variability in the length and abundance of overwintered larvae. The mean length of larvae captured in post-winter surveys was negatively correlated to the proportion of larvae from the southern-most (Downs) winter-spawning component. Furthermore, the mean length of larvae originating from all spawning components has decreased since 1990 suggesting ecosystem-wide changes impacting larval growth potential, most likely due to changes in prey fields. A simple biophysical model assuming temperature-dependent growth and constant mortality underestimated larval growth rates suggesting that larval mortality rates steeply declined with increasing size and/or age during winter as no match with field data could be obtained. In contrast better agreement was found between observed and modelled post-winter abundance for larvae originating from four spawning components when a more complex, physiological-based foraging and growth model was employed using a suite of potential prey field and size-based mortality scenarios. Nonetheless, agreement between field and model-derived estimates was poor for larvae originating from the winter-spawned Downs component. In North Sea herring, the dominant processes impacting larval growth and survival appear to have shifted in time and space highlighting how environmental forcing, ecosystem state and other

  13. Efficacy and longevity of the newly developed catnip oil microcapsules against stable fly oviposition larval growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is one of the most important pests of cattle and costs U.S. cattle producers billions of dollars in losses annually. In this study, the efficacy of catnip oil encapsulated in gelatin in oviposition deterrence and larval growth inhibition in st...

  14. LARVAL SALAMANDER GROWTH RESPONDS TO ENRICHMENT OF A NUTRIENT POOR HEADWATER STREAM

    EPA Science Inventory

    While many studies have measured effects of nutrient enrichment on higher trophic levels in grazing food webs, few such studies exist for detritus-based systems. We measured effects of nitrogen and phosphorus addition on growth of larval Eruycea wilderae in a heterotrophic head...

  15. Larval nutrition affects life history traits in a capital breeding moth.

    PubMed

    Colasurdo, Nadia; Gélinas, Yves; Despland, Emma

    2009-06-01

    Fitness depends not only on resource uptake but also on the allocation of these resources to various life history functions. This study explores the life-history consequences of larval diet in terms not only of larval performance but also of adult body composition and reproductive traits in the forest tent caterpillar (Malacosoma disstria Hübner). Caterpillars were reared on their preferred tree host, trembling aspen (Populus tremuloides), or on one of three artificial foods: high protein:low carbohydrate, equal protein-to-carbohydrate ratio or low protein:high carbohydrate. Survivorship, larval development rate and adult body size were lowest on the carbohydrate-biased diet and similar on the protein-biased and equal-ratio diets. Fecundity increased with body size but did not otherwise differ between diets. Moths reared on the carbohydrate-biased diet allocated a lower proportion of their mass to the ovaries and more to somatic growth whereas those on equal-ratio and protein-biased diets allocated more to reproductive tissue and less to somatic tissue. These differences in allocation to reproduction arose from differences in the size of eggs, an index of offspring quality. No differences were found in lipid and protein content of female ovaries, accessory glands or somatic tissue, or of the whole body of male moths. The findings show that physiological processes regulate the composition of the different components of the adult body. Diet effects occur as differences in overall body size and in relative allocation to these components. Although lepidopterans can, to a large extent, compensate post-ingestively for nutritionally deficient diets, investment in reproduction vs somatic growth depends on the nutrients available.

  16. Efficacy and longevity of newly developed catnip oil microcapsules against stable fly oviposition and larval growth.

    PubMed

    Zhu, J J; Wienhold, B J; Wehrle, J; Davis, D; Chen, H; Taylor, D; Friesen, K; Zurek, L

    2014-06-01

    The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is one of the most important pests of cattle and costs U.S. cattle producers billions of dollars in losses annually. In this study, the efficacy of catnip oil encapsulated in gelatin in oviposition deterrence and larval growth inhibition in stable flies was examined under laboratory conditions. More than 98% inhibition of stable fly larval growth and female oviposition was observed in larval and oviposition media treated with encapsulated catnip oil (0.5 g). Further, dose-response tests showed that as little as 0.1 g of encapsulated catnip oil provided > 85% oviposition deterrence. The release of nepetalactones from the capsules was more rapid when the capsules were placed on a moist substrate rather than a dry substrate. Encapsulated catnip oil also exhibited antibacterial activity, supporting the hypothesis that its inhibition of larval growth may be based on its killing of the bacteria on which larvae feed. The use of encapsulated catnip oil can provide an alternative control strategy for stable fly management.

  17. Stock-specific advection of larval walleye (Sander vitreus) in western Lake Erie: Implications for larval growth, mixing, and stock discrimination

    USGS Publications Warehouse

    Michael Fraker,; Eric J. Anderson,; Cassandra J. May,; Kuan-Yu Chen,; Jeremiah J. Davis,; Kristen M. DeVanna,; Mark R. DuFour,; Elizabeth A. Marschall,; Christine M. Mayer,; Jeffrey G. Miner,; Kevin L. Pangle,; Jeremy J. Pritt,; Roseman, Edward F.; Jeffrey T. Tyson,; Yingming Zhao,; Stuart Ludsin,

    2015-01-01

    Physical processes can generate spatiotemporal heterogeneity in habitat quality for fish and also influence the overlap of pre-recruit individuals (e.g., larvae) with high-quality habitat through hydrodynamic advection. In turn, individuals from different stocks that are produced in different spawning locations or at different times may experience dissimilar habitat conditions, which can underlie within- and among-stock variability in larval growth and survival. While such physically-mediated variation has been shown to be important in driving intra- and inter-annual patterns in recruitment in marine ecosystems, its role in governing larval advection, growth, survival, and recruitment has received less attention in large lake ecosystems such as the Laurentian Great Lakes. Herein, we used a hydrodynamic model linked to a larval walleye (Sander vitreus) individual-based model to explore how the timing and location of larval walleye emergence from several spawning sites in western Lake Erie (Maumee, Sandusky, and Detroit rivers; Ohio reef complex) can influence advection pathways and mixing among these local spawning populations (stocks), and how spatiotemporal variation in thermal habitat can influence stock-specific larval growth. While basin-wide advection patterns were fairly similar during 2011 and 2012, smaller scale advection patterns and the degree of stock mixing varied both within and between years. Additionally, differences in larval growth were evident among stocks and among cohorts within stocks which were attributed to spatiotemporal differences in water temperature. Using these findings, we discuss the value of linked physical–biological models for understanding the recruitment process and addressing fisheries management problems in the world's Great Lakes.

  18. Antidepressants at environmentally relevant concentrations affect predator avoidance behavior of larval fathead minnows (Pimephales promelas).

    USGS Publications Warehouse

    Furlong, Edward T.; Barber, Larry B.; Meghan R. McGee,; Megan A. Buerkley,; Matthew L. Julius,; Vajda, Alan M.; Heiko L. Schoenfuss,; Schultz, Melissa M.; Norris, David O.

    2009-01-01

    The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d and, after hatching, were allowed to grow in control well water until 12 d old. Similarly, posthatch fathead minnows were exposed for 12 d to these compounds. High-speed (1,000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by- frame analysis of latency periods, escape velocities, and total escape response (combination of latency period and escape velocity). When tested 12 d posthatch, fluoxetine and venlafaxine adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 d posthatch did not exhibit altered escape responses when exposed to fluoxetine but were affected by venlafaxine and bupropion exposure. Mixtures of these four antidepressant pharmaceuticals slowed predator avoidance behaviors in larval fathead minnows regardless of the exposure window. The direct impact of reduced C-start performance on survival and, ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.

  19. Antidepressants at environmentally relevant concentrations affect predator avoidance behavior of larval fathead minnows (Pimephales promelas)

    USGS Publications Warehouse

    Painter, M.M.; Buerkley, M.A.; Julius, M.L.; Vajda, A.M.; Norris, D.O.; Barber, L.B.; Furlong, E.T.; Schultz, M.M.; Schoenfuss, H.L.

    2009-01-01

    The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d and, after hatching, were allowed to grow in control well water until 12 d old. Similarly, posthatch fathead minnows were exposed for 12 d to these compounds. High-speed (1,000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency periods, escape velocities, and total escape response (combination of latency period and escape velocity). When tested 12 d posthatch, fluoxetine and venlafaxine adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 d posthatch did not exhibit altered escape responses when exposed to fluoxetine but were affected by venlafaxine and bupropion exposure. Mixtures of these four antidepressant pharmaceuticals slowed predator avoidance behaviors in larval fathead minnows regardless of the exposure window. The direct impact of reduced C-start performance on survival and, ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration. ?? 2009 SETAC.

  20. Larval exposure to azadirachtin affects fitness and oviposition site preference of Drosophila melanogaster.

    PubMed

    Bezzar-Bendjazia, Radia; Kilani-Morakchi, Samira; Aribi, Nadia

    2016-10-01

    Azadirachtin, a biorational insecticide, is one of the prominent biopesticide commercialized today and represent an alternative to conventional insecticides. The current study examined the lethal and sublethal effects of azadirachtin on Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae) as biological model. Various doses ranging from 0.1 to 2μg were applied topically on early third instar larvae and the cumulative mortality of immature stage was determined. In second series of experiments, azadirachtin was applied at its LD25 (0.28μg) and LD50 (0.67μg) and evaluated on fitness (development duration, fecundity, adult survival) and oviposition site preference with and without choice. Results showed that azadirachtin increased significantly at the two tested doses the duration of larval and pupal development. Moreover, azadirachtin treatment reduced significantly adult's survival of both sex as compared to control. In addition, azadirachtin affected fecundity of flies by a significant reduction of the number of eggs laid. Finally results showed that females present clear preference for oviposition in control medium. Pre-imaginal exposure (L3) to azadirachtin increased aversion to this substance suggesting a memorability of the learned avoidance. The results provide some evidence that larval exposure to azadirachtin altered adult oviposition preference as well as major fitness traits of D. melanogaster. Theses finding may reinforce behavioural avoidance of azadirachtin and contribute as repellent strategies in integrated pest management programmes.

  1. Juvenile frogs compensate for small metamorph size with terrestrial growth: Overcoming the effects of larval density and insecticide exposure

    USGS Publications Warehouse

    Boone, M.D.

    2005-01-01

    I reared four species of anurans (Rana sphenocephala [Southern Leopard Frog], Rana blairi [Plains Leopard Frog], Rana clamitans [Green Frog], and Bufo woodhousii [Woodhouse's Toad]) for seven to 12 months in small, outdoor terrestrial enclosures (1 x 2 m) to examine the consequences of larval competition (via density) and contaminant exposure (via the insecticide carbaryl). I added six Rana clamitans, eight Rana sphenocephala, eight Rana blairi, and 10 Bufo woodhousii to terrestrial enclosures shortly after metamorphosis and recaptured them during the following spring. All anurans from low-density ponds were significantly larger than those from high-density ponds, but these size differences did not significantly affect survival to or size at spring emergence. However, R. sphenocephala, R. blairi, and R. clamitans that survived to spring had been larger at metamorphosis on average than those that did not survive; in contrast, B. woodhousii that survived the winter were smaller at metamorphosis on average than those that did not survive. Carbaryl exposure affected mass at metamorphosis of R. clamitans and B. woodhousii that were added to enclosures, but this difference disappeared or did not increase by spring emergence. Overall, exposure to carbaryl during the larval period did not have any apparent effects on survival or growth during the terrestrial phase. In my study, anurans were able to offset small size at metamorphosis with terrestrial growth, although there was a trend of reduced overwinter survival for ranid species that metamorphosed at a smaller size. Copyright 2005 Society for the Study of Amphibians and Reptiles.

  2. Artificial selection on larval growth curves in Tribolium: correlated responses and constraints.

    PubMed

    Irwin, K K; Carter, P A

    2014-10-01

    Body size is often constrained from evolving. Although artificial selection on body size in insects frequently results in a sizable response, these responses usually bear fitness costs. Further, these experiments tend to select only on size at one landmark age, rather than selecting for patterns of growth over the whole larval life stage. To address whether constraints may be caused by larval growth patterns rather than final size, we implemented a function-valued (FV) trait method of selection, in which entire larval growth curves from Tribolium were artificially selected. The selection gradient function used was previously predicted to give the maximal response and was implemented using a novel selection index in the FV framework. Results indicated a significant response after one generation of selection, but no response in subsequent generations. Correlated responses included increased mortality, increased critical weight, and decreased development time (DT). The lack of response in size and development time after the first generation was likely caused by increased mortality suffered in selected lines; we demonstrated that the selection criterion caused both increased body size and increased mortality. We conclude that artificial selection on continuous traits using FV methods is very efficient and that the constraint of body size evolution is likely caused by a suite of trade-offs with other traits.

  3. Larval Habitat Substrates Could Affect the Biology and Vectorial Capacity of Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Shah, Rizwan Mustafa; Ali, Qasim; Alam, Mehboob; Shad, Sarfraz Ali; Majeed, Shahid; Riaz, Muhammad; Binyameen, Muhammad

    2016-12-25

    Culex quinquefasciatus Say is an important disease vector throughout much of the world. Experiments were conducted to determine the effects of different larval habitat substrates on the fitness and biting efficiency of Cx. quinquefasciatus adults. Our findings indicate that the development time (egg to adult) of larvae reared in irrigation water was 8.63 d while that of larvae reared in distilled water was 17.10 d (Effect size = 0.95). However, the rate of adult emergence was similar for all the tested treatments. Furthermore, the mean weight of an egg raft varied between larval habitats: distilled water (1.83 mg), rainfall water (1.25 mg), irrigation water (1.52 mg), and sewerage water (2.52 mg) (Effect size = 0.91). But, the fecundity (eggs per female) and hatchability (%) were statistically similar in all the rearing mediums (Effect size = 0.79). Longevity of females in all the tested populations did not differ significantly (Effect size = 0.91). The mean relative growth rates of larvae reared in tap water (0.80) and distilled water (0.86) habitats were lower than growth rates in all other rearing habitats (Effect size = 0.96). The intrinsic rate of natural increase in tap water (0.27) and irrigation water (0.35) was significantly higher than that in distilled water (0.09) and sewerage water (0.16) (Effect size = 0.84). Adults reared in rain water had the highest biting efficiency among all the tested populations. These results provide useful information for the management of Cx. quinquefasciatus.

  4. RNA interference of chitin synthase genes inhibits chitin biosynthesis and affects larval performance in Leptinotarsa decemlineata (Say)

    PubMed Central

    Shi, Ji-Feng; Mu, Li-Li; Chen, Xu; Guo, Wen-Chao; Li, Guo-Qing

    2016-01-01

    Dietary introduction of bacterially expressed double-stranded RNA (dsRNA) has great potential for management of Leptinotarsa decemlineata. Identification of the most attractive candidate genes for RNA interference (RNAi) is the first step. In the present paper, three complete chitin synthase cDNA sequences (LdChSAa, LdChSAb and LdChSB) were cloned. LdChSAa and LdChSAb, two splicing variants of LdChSA gene, were highly expressed in ectodermally-derived epidermal cells forming epidermis, trachea, foregut and hindgut, whereas LdChSB was mainly transcribed in midgut cells. Feeding bacterially expressed dsChSA (derived from a common fragment of LdChSAa and LdChSAb), dsChSAa, dsChSAb and dsChSB in the second- and fourth-instar larvae specifically knocked down their target mRNAs. RNAi of LdChSAa+LdChSAb and LdChSAa lowered chitin contents in whole body and integument samples, and thinned tracheal taenidia. The resulting larvae failed to ecdyse, pupate, or emerge as adults. Comparably, knockdown of LdChSAb mainly affected pupal-adult molting. The LdChSAb RNAi pupae did not completely shed the old larval exuviae, which caused failure of adult emergence. In contrast, silencing of LdChSB significantly reduced foliage consumption, decreased chitin content in midgut sample, damaged midgut peritrophic matrix, and retarded larval growth. As a result, the development of the LdChSB RNAi hypomorphs was arrested. Our data reveal that these LdChSs are among the effective candidate genes for an RNAi-based control strategy against L. decemlineata. PMID:27877084

  5. A Novel Forward Genetic Screen for Identifying Mutations Affecting Larval Neuronal Dendrite Development in Drosophila melanogaster

    PubMed Central

    Medina, Paul Mark B.; Swick, Lance L.; Andersen, Ryan; Blalock, Zachary; Brenman, Jay E.

    2006-01-01

    Vertebrate and invertebrate dendrites are information-processing compartments that can be found on both central and peripheral neurons. Elucidating the molecular underpinnings of information processing in the nervous system ultimately requires an understanding of the genetic pathways that regulate dendrite formation and maintenance. Despite the importance of dendrite development, few forward genetic approaches have been used to analyze the latest stages of dendrite development, including the formation of F-actin-rich dendritic filopodia or dendritic spines. We developed a forward genetic screen utilizing transgenic Drosophila second instar larvae expressing an actin, green fluorescent protein (GFP) fusion protein (actin∷GFP) in subsets of sensory neurons. Utilizing this fluorescent transgenic reporter, we conducted a forward genetic screen of >4000 mutagenized chromosomes bearing lethal mutations that affected multiple aspects of larval dendrite development. We isolated 13 mutations on the X and second chromosomes composing 11 complementation groups affecting dendrite outgrowth/branching, dendritic filopodia formation, or actin∷GFP localization within dendrites in vivo. In a fortuitous observation, we observed that the structure of dendritic arborization (da) neuron dendritic filopodia changes in response to a changing environment. PMID:16415365

  6. Effects of ocean acidification on the larval growth of olive flounder (Paralichthys olivaceus)

    NASA Astrophysics Data System (ADS)

    Kim, K.-S.; Shim, J. H.; Kim, S.

    2013-04-01

    Little is known about how marine fishes respond to the reduced pH condition caused by the increased CO2 in the atmosphere. We investigated the effects of CO2 concentration on the growth of olive flounder (Paralichthys olivaceus) larvae. Newly hatched larvae were reared in three different concentrations of CO2 (574, 988 and 1297 μatm CO2) in temperature-controlled water tanks until metamorphosis (4 weeks). Body lengths, weights, and the concentration of some chemical elements in larval tissue were measured at the completion of each experiment, and experiment was repeated three times in May, June, and July 2011. Results indicated that body length and weight of flounder larvae were significantly increased with increasing CO2 concentration (P < 0.05). Daily growth rates of flounder larvae were higher (0.391 mm) from the high CO2 concentration (1297 μatm) than those (0.361 mm and 0.360 mm) from the lower ones (988 and 574 μatm).The measurement on some chemical elements (Ca, Fe, Cu, Zn and Sr) in fish tissue also revealed the increasing tendency of element concentration with increasing CO2 in seawater, although statistical significance cannot be tested due to the single measurement. It suggests that there are enrichment processes of these cations in larval tissue in the low pH condition.

  7. Insulin- and Warts-Dependent Regulation of Tracheal Plasticity Modulates Systemic Larval Growth during Hypoxia in Drosophila melanogaster

    PubMed Central

    Wong, Daniel M.; Shen, Zhouyang; Owyang, Kristin E.; Martinez-Agosto, Julian A.

    2014-01-01

    Adaptation to dynamic environmental cues during organismal development requires coordination of tissue growth with available resources. More specifically, the effects of oxygen availability on body size have been well-documented, but the mechanisms through which hypoxia restricts systemic growth have not been fully elucidated. Here, we characterize the larval growth and metabolic defects in Drosophila that result from hypoxia. Hypoxic conditions reduced fat body opacity and increased lipid droplet accumulation in this tissue, without eliciting lipid aggregation in hepatocyte-like cells called oenocytes. Additionally, hypoxia increased the retention of Dilp2 in the insulin-producing cells of the larval brain, associated with a reduction of insulin signaling in peripheral tissues. Overexpression of the wildtype form of the insulin receptor ubiquitously and in the larval trachea rendered larvae resistant to hypoxia-induced growth restriction. Furthermore, Warts downregulation in the trachea was similar to increased insulin receptor signaling during oxygen deprivation, which both rescued hypoxia-induced growth restriction, inhibition of tracheal molting, and developmental delay. Insulin signaling and loss of Warts function increased tracheal growth and augmented tracheal plasticity under hypoxic conditions, enhancing oxygen delivery during periods of oxygen deprivation. Our findings demonstrate a mechanism that coordinates oxygen availability with systemic growth in which hypoxia-induced reduction of insulin receptor signaling decreases plasticity of the larval trachea that is required for the maintenance of systemic growth during times of limiting oxygen availability. PMID:25541690

  8. Factors affecting fungus-induced larval mortality in Anopheles gambiae and Anopheles stephensi

    PubMed Central

    2010-01-01

    Background Entomopathogenic fungi have shown great potential for the control of adult malaria vectors. However, their ability to control aquatic stages of anopheline vectors remains largely unexplored. Therefore, how larval characteristics (Anopheles species, age and larval density), fungus (species and concentration) and environmental effects (exposure duration and food availability) influence larval mortality caused by fungus, was studied. Methods Laboratory bioassays were performed on the larval stages of Anopheles gambiae and Anopheles stephensi with spores of two fungus species, Metarhizium anisopliae and Beauveria bassiana. For various larval and fungal characteristics and environmental effects the time to death was determined and survival curves established. These curves were compared by Kaplan Meier and Cox regression analyses. Results Beauveria bassiana and Metarhizium anisopliae caused high mortality of An. gambiae and An. stephensi larvae. However, Beauveria bassiana was less effective (Hazard ratio (HR) <1) compared to Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR < 1). The effect of increase in fungus concentration on larval mortality was influenced by spore clumping. One day exposure to fungal spores was found to be equally effective as seven days exposure. In different exposure time treatments 0 - 4.9% of the total larvae, exposed to fungus, showed infection at either the pupal or adult stage. Mortality rate increased with increasing larval density and amount of available food. Conclusions This study shows that both fungus species have potential to kill mosquitoes in the larval stage, and that mortality rate depends on fungus species itself, larval stage targeted, larval density and amount of nutrients available to the larvae. Increasing the concentration of fungal spores or reducing the exposure time to spores did not show a proportional

  9. Growth and development of larval green frogs (Rana clamitans) exposed to multiple doses of an insecticide

    USGS Publications Warehouse

    Boone, M.D.; Bridges, C.M.; Rothermel, B.B.

    2001-01-01

    Our objective was to determine how green frogs (Rana clamitans) are affected by multiple exposures to a sublethal level of the carbamate insecticide, carbaryl, in outdoor ponds. Tadpoles were added to 1,000-1 ponds at a low or high density which were exposed to carbaryl 0, 1, 2, or 3 times. Length of the larval period, mass, developmental stage, tadpole survival, and proportion metamorphosed were used to determine treatment effects. The frequency of dosing affected the proportion of green frogs that reached metamorphosis and the developmental stage of tadpoles. Generally, exposure to carbaryl increased rates of metamorphosis and development. The effect of the frequency of carbaryl exposure on development varied with the density treatment; the majority of metamorphs and the most developed tadpoles came from high-density ponds exposed to carbaryl 3 times. This interaction suggests that exposure to carbaryl later in the larval period stimulated metamorphosis, directly or indirectly, under high-density conditions. Our study indicates that exposure to a contaminant can lead to early initiation of metamorphosis and that natural biotic factors can mediate the effects of a contaminant in the environment.

  10. Growth and mortality of larval sunfish in backwaters of the upper Mississippi River

    USGS Publications Warehouse

    Zigler, S.J.; Jennings, C.A.

    1993-01-01

    The authors estimated the growth and mortality of larval sunfish Lepomis spp. in backwater habitats of the upper Mississippi River with an otolith-based method and a length-based method. Fish were sampled with plankton nets at one station in Navigation Pools 8 and 14 in 1989 and at two stations in Pool 8 in 1990. For both methods, growth was modeled with an exponential equation, and instantaneous mortality was estimated by regressing the natural logarithm of fish catch for each 1-mm size-group against the estimated age of the group, which was derived from the growth equations. At two of the stations, the otolith-based method provided more precise estimates of sunfish growth than the length-based method. We were able to compare length-based and otolith-based estimates of sunfish mortality only at the two stations where we caught the largest numbers of sunfish. Estimates of mortality were similar for both methods in Pool 14, where catches were higher, but the length-based method gave significantly higher estimates in Pool 8, where the catches were lower. The otolith- based method required more laboratory analysis, but provided better estimates of the growth and mortality than the length-based method when catches were low. However, the length-based method was more cost- effective for estimating growth and mortality when catches were large.

  11. Larval starvation reduces responsiveness to feeding stimuli and does not affect feeding preferences in a butterfly.

    PubMed

    Kehl, Tobias; Fischer, Klaus

    2012-07-01

    It is commonly assumed that holometabolic insects such as Lepidoptera rely primarily on larval storage reserves for reproduction. Recent studies though have documented a prominent role of adult-derived carbohydrates for butterfly reproduction. Moreover, a few studies have shown that adult butterflies may also benefit from adult-derived amino acids, at least when larval storage reserves are reduced. Given that in holometabolous insects larval deficiencies are carried over into the adult stage, reduced storage reserves have the potential to modulate adult feeding preferences and responses in order to allow for a successful compensation. We tested this hypothesis here in the fruit-feeding butterfly Bicyclus anynana using larval food stress to manipulate storage reserves. Alcohols (methanol, ethanol, butanol, propanol), sugars (maltose, glucose, fructose, sucrose), and acetic acid acted as feeding stimuli, while butterflies did not respond to other substances such as amino acids, yeast, salts, or vitamins. Contrary to expectations, stressed butterflies showed a weaker response than controls to several feeding stimuli. In preference tests, butterflies preferred sugar solutions containing proline, arginine, glutamic acid, acetic acid, or ethanol over plain sugar solutions, but discriminated against salts. However, there were no general differences among starved and control butterflies. We conclude that larval food-stress does not elicit compensatory feeding behavior such as a stronger preference for amino acids or other essential nutrients in B. anynana. Instead, the stress imposed by a period of starvation yielded negative effects.

  12. Growth performance of larval and juvenile manila clam ( Ruditapes philippinarum) from divergently selected individuals of a full-sib family

    NASA Astrophysics Data System (ADS)

    Huo, Zhongming; Li, Xiaotong; Sun, Qian; Li, Yongren; Zhang, Xuekai; Yan, Xiwu; Yang, Feng

    2016-12-01

    In this study, the method of divergent selection was employed to test the larval and juvenile growth performance within a full-sib family of Manila clam Ruditapes philippinarum. The 10% largest and 10% smallest clam individuals (on the basis of shell length) of a full-sib family were selected as parents for the fast and slow growing lines, respectively. The difference in shell length was significant among the three lines (fast, control, and slow) tested. The sequence of shell length were fast line > control line > slow line. The responses to selection, realized heritability, and genetic gain were 0.06%-0.81%, 0.04%-0.47% and 0.58%-18.89% in the fast direction, respectively; and were 0.14%-1.27%, 0.08%-0.73%, and 0.31%-49.03% in the slow direction, respectively. The results suggested that there was a large portion of additive genetic variance affecting the growth in the full-sib family. Selection in the fast direction within the full-sib family would greatly improve the growth of R. philippinarum.

  13. Effects of temperature on embryonic and early larval growth and development in the rough-skinned newt (Taricha granulosa).

    PubMed

    Smith, Geoffrey D; Hopkins, Gareth R; Mohammadi, Shabnam; M Skinner, Heather; Hansen, Tyler; Brodie, Edmund D; French, Susannah S

    2015-07-01

    We investigated the effects of temperature on the growth and development of embryonic and early larval stages of a western North American amphibian, the rough-skinned newt (Taricha granulosa). We assigned newt eggs to different temperatures (7, 14, or 21°C); after hatching, we re-assigned the newt larvae into the three different temperatures. Over the course of three to four weeks, we measured total length and developmental stage of the larvae. Our results indicated a strong positive relationship over time between temperature and both length and developmental stage. Importantly, individuals assigned to cooler embryonic temperatures did not achieve the larval sizes of individuals from the warmer embryonic treatments, regardless of larval temperature. Our investigation of growth and development at different temperatures demonstrates carry-over effects and provides a more comprehensive understanding of how organisms respond to temperature changes during early development.

  14. The larval development of Habronema muscae (Nematoda: Habronematidae) affects its intermediate host, Musca domestica (Diptera: Muscidae).

    PubMed

    Schuster, Rolf Karl; Sivakumar, Saritha

    2017-02-01

    Although the life cycle of the equid stomach parasite Habronema muscae was disclosed more than 100 years ago, little is known about the effect of the developing nematode larvae in its intermediate host, Musca domestica. In a series of experiments, freshly hatched M. domestica larvae were exposed to H. muscae eggs contained in a faecal sample of a naturally infected horse. In daily intervals, 50 fly larvae were removed and transferred on a parasite-free larval rearing medium where they completed their development. Hatched flies were examined for the presence of Habronema third-stage larvae. In two subsequent control groups, flies spend their entire larval life in contaminated horse faeces and in a parasite-free larval rearing medium, respectively. Out of the 700 fly larvae used in the infection experiments, 304 developed into adult flies of which 281 were infected. The average nematode larval burden rose from 3.6 in the group with the shortest exposure to more than 25 in the groups with the longest exposure. The proportion of larvae that developed into the adult insect fell from 82 % in the uninfected control group to 27 % in the positive control group. The pupae of the positive control group were smaller and lighter than those of the uninfected control group. Lower pupal size and weight in the positive control group as well as a lower insect developing rate might be attributed to the destruction of adipose cells in the maggots by Habronema larvae.

  15. Larval and juvenile growth performance of Manila clam hybrids of two full-sib families

    NASA Astrophysics Data System (ADS)

    Huo, Zhongming; Yan, Xiwu; Zhao, Liqiang; Liang, Jian; Yang, Feng; Zhang, Guofan

    2015-06-01

    In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam ( Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A × ♀B ( Hp varied between 10.41% and 68.27%) displayed larger heterosis than ♂B × ♀A ( Hp varied between 1.89% and 32.33%) did, suggesting that ♂A × ♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability (GCA), special combining ability (SCA) and interaction (I) were significant in shell length (P < 0.05), indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A × ♀B was higher than that of ♂B × ♀A at both larval and juvenile stages. This confirmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.

  16. GROWTH AND CHANGES IN BIOCHEMICAL COMPOSITION DURING LARVAL DEVELOPMENT OF THE STONE CRAB, MENIPPE ADINA WILLIAMS AND FELDER, 1986

    EPA Science Inventory

    Larval development in Menippe adina was associated with changes in weight and biochemical composition. Larvae of the stone crab, M. adina, were mass-reared under laboratory conditions (28|C; 20o/ooS) from hatching to the megalopal stage. Growth in M. adina is exponential througho...

  17. Cloning and characterization of peter pan, a novel Drosophila gene required for larval growth.

    PubMed

    Migeon, J C; Garfinkel, M S; Edgar, B A

    1999-06-01

    We identified a new Drosophila gene, peter pan (ppan), in a screen for larval growth-defective mutants. ppan mutant larvae do not grow and show minimal DNA replication but can survive until well after their heterozygotic siblings have pupariated. We cloned the ppan gene by P-element plasmid rescue. ppan belongs to a highly conserved gene family that includes Saccharomyces cerevisiae SSF1 and SSF2, as well as Schizosaccharomyces pombe, Arabidopsis, Caenorhabditis elegans, mouse, and human homologues. Deletion of both SSF1 and SSF2 in yeast is lethal, and depletion of the gene products causes cell division arrest. Mosaic analysis of ppan mutant clones in Drosophila imaginal disks and ovaries demonstrates that ppan is cell autonomous and required for normal mitotic growth but is not absolutely required for general biosynthesis or DNA replication. Overexpression of the wild-type gene causes cell death and disrupts the normal development of adult structures. The ppan gene family appears to have an essential and evolutionarily conserved role in cell growth.

  18. Field study suggests that sex determination in sea lamprey is directly influenced by larval growth rate

    USGS Publications Warehouse

    Johnson, Nicholas; Swink, William D.; Brenden, Travis O.

    2017-01-01

    Sex determination mechanisms in fishes lie along a genetic-environmental continuum and thereby offer opportunities to understand how physiology and environment interact to determine sex. Mechanisms and ecological consequences of sex determination in fishes are primarily garnered from teleosts, with little investigation into basal fishes. We tagged and released larval sea lamprey (Petromyzon marinus) into unproductive lake and productive stream environments. Sex ratios produced from these environments were quantified by recapturing tagged individuals as adults. Sex ratios from unproductive and productive environments were initially similar. However, sex ratios soon diverged, with unproductive environments becoming increasingly male-skewed and productive environments becoming less male-skewed with time. We hypothesize that slower growth in unproductive environments contributed to the sex ratio differences by directly influencing sex determination. To the best of our knowledge, this is the first study suggesting that growth rate in a fish species directly influences sex determination; other studies have suggested that the environmental variables to which sex determination is sensitive (e.g. density, temperature) act as cues for favourable or unfavourable growth conditions. Understanding mechanisms of sex determination in lampreys may provide unique insight into the underlying principles of sex determination in other vertebrates and provide innovative approaches for their management where valued and invasive.

  19. Grape variety affects larval performance and also female reproductive performance of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae).

    PubMed

    Moreau, J; Benrey, B; Thiéry, D

    2006-04-01

    For insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.

  20. Gene-environment interplay in Drosophila melanogaster: chronic nutritional deprivation in larval life affects adult fecal output.

    PubMed

    Urquhart-Cronish, Mackenzie; Sokolowski, Marla B

    2014-10-01

    Life history consequences of stress in early life are varied and known to have lasting impacts on the fitness of an organism. Gene-environment interactions play a large role in how phenotypic differences are mediated by stressful conditions during development. Here we use natural allelic 'rover/sitter' variants of the foraging (for) gene and chronic early life nutrient deprivation to investigate gene-environment interactions on excretion phenotypes. Excretion assay analysis and a fully factorial nutritional regimen encompassing the larval and adult life cycle of Drosophila melanogaster were used to assess the effects of larval and adult nutritional stress on adult excretion phenotypes. Natural allelic variants of for exhibited differences in the number of fecal spots when they were nutritionally deprived as larvae and well fed as adults. for mediates the excretion response to chronic early-life nutritional stress in mated female, virgin female, and male rovers and sitters. Transgenic manipulations of for in a sitter genetic background under larval but not adult food deprivation increases the number of fecal spots. Our study shows that food deprivation early in life affects adult excretion phenotypes and these excretion differences are mediated by for.

  1. UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency.

    PubMed

    Martin, Mélissa; Théry, Marc; Rodgers, Gwendolen; Goven, Delphine; Sourice, Stéphane; Mège, Pascal; Secondi, Jean

    2016-02-01

    We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UV+) or absence (UV-) of UV light (developmental treatments), and tested their predation efficiency under UV+ and UV- light (testing treatments). We found that both SWS1 opsin expression and predation efficiency were significantly reduced in the UV- developmental group. Larvae in the UV- testing environment displayed consistently lower predation efficiency regardless of their developmental treatment. These results prove for the first time, we believe, functional UV vision and developmental plasticity of UV sensitivity in an amphibian at the larval stage. They also demonstrate that UV wavelengths enhance predation efficiency and suggest that the magnitude of the behavioural response depends on retinal properties induced by the developmental lighting environment.

  2. Testing the effect of dietary carotenoids on larval survival, growth and development in the critically endangered southern corroboree frog.

    PubMed

    Byrne, Phillip G; Silla, Aimee J

    2017-03-01

    The success of captive breeding programs (CBPs) for threatened species is often limited due to a lack of knowledge of the nutritional conditions required for optimal growth and survival. Carotenoids are powerful antioxidants known to accelerate vertebrate growth and reduce mortality. However, the effect of carotenoids on amphibian life-history traits remains poorly understood. The aim of our study was to use a manipulative laboratory experiment to test the effect of dietary-carotenoid supplementation during the larval life stage on the survival, growth and development of the critically endangered southern corroboree frog (Pseudophryne corroboree). Larvae were fed either a carotenoid supplemented diet or an unsupplemented diet and the survival, growth and development of individuals was monitored and compared. There was no significant effect of dietary treatment on larval survival, growth rate, time taken to reach metamorphosis, or body size at metamorphosis. Our findings provide no evidence that carotenoid supplementation during the larval life stage improves the growth and development of southern corroboree frogs. However, because the carotenoid dose used in our study did not have any detrimental effects on P. corroboree larvae, but has previously been shown to improve adult coloration, immunity, and exercise performance, carotenoid supplementation should be considered when evaluating the nutritional requirements of P. corroboree in captivity. Carotenoid supplementation studies are now required for a diversity of anuran species to determine the effects of carotenoids on amphibian survival, growth and development. Understanding the effects of dietary carotenoids on different life-history traits may assist with amphibian captive breeding and conservation.

  3. Growth and reproductive costs of larval defence in the aposematic lepidopteran Pieris brassicae.

    PubMed

    Higginson, Andrew D; Delf, Jon; Ruxton, Graeme D; Speed, Michael P

    2011-03-01

    1. Utilization of plant secondary compounds for antipredator defence is common in immature herbivorous insects. Such defences may incur a cost to the animal, either in terms of survival, growth rate or in the reproductive success. 2. A common defence in lepidopterans is the regurgitation of semi-digested material containing the defensive compounds of the food plant, a defence which has led to gut specialization in this order. Regurgitation is often swift in response to cuticular stimulation and deters predators from consuming or parasitizing the larva. The loss of food and other gut material seems likely to impact on fitness, but evidence is lacking. 3. Here, we raised larvae of the common crop pest Pieris brassicae on commercial cabbage leaves, simulated predator attacks throughout the larval period, and measured life-history responses. 4. We found that the probability of survival to pupation decreased with increasing frequency of attacks, but this was because of regurgitation rather than the stimulation itself. There was a growth cost to the defence such that the more regurgitant that individuals produced over the growth period, the smaller they were at pupation. 5. The number of mature eggs in adult females was positively related to pupal mass, but this relationship was only found when individuals were not subjected to a high frequency of predator simulation. This suggests that there might be cryptic fitness costs to common defensive responses that are paid despite apparent growth rate being maintained. 6. Our results demonstrate a clear life-history cost of an antipredator defence in a model pest species and show that under certain conditions, such as high predation threat, the expected relationship between female body size and potential fecundity can be disrupted.

  4. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB)

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations from 1 ...

  5. Strong influences of larval diet history on subsequent post-settlement growth in the freshwater mollusc Dreissena polymorpha.

    PubMed Central

    Wacker, Alexander; von Elert, Eric

    2002-01-01

    A significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing the life history and development of freshwater invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the proposal that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells, which are deficient in polyunsaturated fatty acids (PUFAs) and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the post-metamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet. Hence, low food quantity or low food quality during the larval stage of D. polymorpha, lead to irreversible effects for post-metamorphic animals and are related to inferior competitive abilities. PMID:12396485

  6. Growth variability and stable isotope composition of two larval carangid fishes in the East Australian Current: The role of upwelling in the separation zone

    NASA Astrophysics Data System (ADS)

    Syahailatua, Augy; Taylor, Matthew D.; Suthers, Iain M.

    2011-03-01

    The larvae of two carangid fishes, silver trevally ( Pseudocaranx dentex) and yellowtail scad ( Trachurus novaezelandiae), were compared among coastal water masses and the East Australian Current (EAC). Samples followed a north to south gradient including a southern region of upwelling, generated as the EAC separated from the coast. Mean larval carangid densities were greater in the mixed layer (10-30 m) than the surface, but there was no difference between inshore and offshore stations or along latitudinal gradients. Overall, P. dentex recent larval growth over two days pre-capture was faster than T. novaezelandiae, and faster at inshore, coastal stations than in the EAC. Integrated larval growth rate (mm d -1) was usually faster at inshore stations for both species. T. novaezelandiae were enriched in both nitrogen (δ 15N) and carbon (δ 13C) stable isotopes relative to P. dentex. Larvae of both species captured within the upwelling region were enriched in δ 15N and depleted in δ 13C relative to other sites. Recent larval growth had a significant positive relationship with fluorescence (as a proxy of chlorophyll a biomass), and integrated larval growth rate had a significant positive relationship with fluorescence and larval isotope (δ 15N) composition. Recent and integrated growth of larval T. novaezelandiae and P. dentex was enhanced by EAC separation and upwelling, and also in coastal water; stimulated by food availability, and potentially through exploitation of a different trophic niche.

  7. Socioeconomic status affects mosquito (Diptera: Culicidae) larval habitat type availability and infestation level.

    PubMed

    Dowling, Zara; Ladeau, Shannon L; Armbruster, Peter; Biehler, Dawn; Leisnham, Paul T

    2013-07-01

    Mosquito populations are largely regulated by processes occurring at the larval stage. We sampled mosquito larval microhabitats (mostly water-holding containers) in six neighborhoods in the Washington, DC, area that varied in socioeconomic status (SES) and housing structure (row houses vs. stand-alone houses) to test associations among these neighborhood characteristics, microhabitat abundance and parameters, and mosquito occurrence and densities. Thirty-four percent (33.9%) of sampled microhabitats contained mosquito larvae, and 93.1% of larvae were Aedes albopictus Skuse or Culex pipiens L. Five specific container types (drains, corrugated flexible drainpipes, planters, garbage cans, and buckets) accounted for the majority of water-holding (56.0%) and mosquito-positive (50.6%) microhabitats sampled. We found no associations between SES or housing structure with total microhabitat abundance per yard, mosquito occurrence or mosquito densities per microhabitat. In contrast, container purpose varied with SES, with low SES neighborhoods having greater numbers of disused containers and lower numbers of functional containers than low and medium SES neighborhoods. Ae. albopictus were 83% more abundant in disused containers, whereas Cx. pipiens were more abundant in structural and functional containers, possibly owing to species-specific oviposition and development related to water quality. Ae. albopictus densities increased over the summer, whereas Cx. pipiens densities remained constant. Ae. albopictus is usually the dominant pest in urban areas in the eastern United States; therefore, integrated mosquito management programs should incorporate the elimination of disused containers to reduce its infestation and adult production, especially in low SES neighborhoods where they occur most frequently.

  8. Excess dietary cholesterol may have an adverse effect on growth performance of early post-larval Litopenaeus vannamei.

    PubMed

    Niu, Jin; Chen, Peng-Fei; Tian, Li-Xia; Liu, Yong-Jian; Lin, Hei-Zhao; Yang, Hui-Jun; Liang, Gui-Ying

    2012-06-25

    One experiment was conducted to determine the nutritive value of cholesterol for post-larval shrimp, Litopenaeus vannamei. Four isoenergetic and isonitrogenous diets supplemented with four levels of cholesterol (D1, D2, D3 and D4 with 0, 0.5%, 1% and 2% cholesterol, respectively) were fed to triplicate groups of L. vannamei shrimp (mean initial wet weight 0.8 mg) for 27 days. After the trial, shrimp fed the D1 diet had the best growth performance (final body weights: FBW; weight gain: WG; specific growth rate: SGR), while there was no significant difference between diet treatments with respect to survival. The whole body crude protein level in the shrimp decreased with the increase in dietary cholesterol levels, while the whole body crude lipid level in shrimps in the D4 diet treatment was significantly higher (P < 0.05) than in other diet treatments. Dietary analysis indicated that the D1 diet contained 0.92% cholesterol prior to supplementation, which may have satisfied the dietary cholesterol requirement of post-larval L. vannamei; excess dietary cholesterol may thus lead to adverse effects on the growth performance of post-larval shrimp.

  9. Landscape distribution of food and nesting sites affect larval diet and nest size, but not abundance of Osmia bicornis.

    PubMed

    Coudrain, Valérie; Rittiner, Sarah; Herzog, Felix; Tinner, Willy; Entling, Martin H

    2016-10-01

    Habitat fragmentation is a major threat for beneficial organisms and the ecosystem services they provide. Multiple-habitat users such as wild bees depend on both nesting and foraging habitat. Thus, they may be affected by the fragmentation of at least two habitat types. We investigated the effects of landscape-scale amount of and patch isolation from both nesting habitat (woody plants) and foraging habitat (specific pollen sources) on the abundance and diet of Osmia bicornis L. Trap-nests of O. bicornis were studied in 30 agricultural landscapes of the Swiss Plateau. Nesting and foraging habitats were mapped in a radius of 500 m around the sites. Pollen composition of larval diet changed as isolation to the main pollen source, Ranunculus, increased, suggesting that O. bicornis adapted its foraging strategy in function of the nest proximity to main pollen sources. Abundance of O. bicornis was neither related to isolation or amount of nesting habitat nor to isolation or abundance of food plants. Surprisingly, nests of O. bicornis contained fewer larvae in sites at forest edge compared to isolated sites, possibly due to higher parasitism risk. This study indicates that O. bicornis can nest in a variety of situations by compensating scarcity of its main larval food by exploiting alternative food sources.

  10. Larval food quantity affects development time, survival and adult biological traits that influence the vectorial capacity of Anopheles darlingi under laboratory conditions

    PubMed Central

    2012-01-01

    Background The incidence of malaria in the Amazon is seasonal and mosquito vectorial capacity parameters, including abundance and longevity, depend on quantitative and qualitative aspects of the larval diet. Anopheles darlingi is a major malaria vector in the Amazon, representing >95% of total Anopheles population present in the Porto Velho region. Despite its importance in the transmission of the Plasmodium parasite, knowledge of the larval biology and ecology is limited. Studies regarding aspects of adult population ecology are more common than studies on larval ecology. However, in order develop effective control strategies and laboratory breeding conditions for this species, more data on the factors affecting vector biology is needed. The aim of the present study is to assess the effects of larval food quantity on the vectorial capacity of An. darling under laboratory conditions. Methods Anopheles darlingi was maintained at 28°C, 80% humidity and exposed to a daily photoperiod of 12 h. Larvae were divided into three experimental groups that were fed either a low, medium, or high food supply (based on the food amounts consumed by other species of culicids). Each experiment was replicated for six times. A cohort of adults were also exposed to each type of diet and assessed for several biological characteristics (e.g. longevity, bite frequency and survivorship), which were used to estimate the vectorial capacity of each experimental group. Results The group supplied with higher food amounts observed a reduction in development time while larval survival increased. In addition to enhanced longevity, increasing larval food quantity was positively correlated with increasing frequency of bites, longer blood meal duration and wing length, resulting in greater vectorial capacity. However, females had greater longevity than males despite having smaller wings. Conclusions Overall, several larval and adult biological traits were significantly affected by larval food

  11. Sitona lineatus (Coleoptera: Curculionidae) Larval Feeding on Pisum sativum L. Affects Soil and Plant Nitrogen.

    PubMed

    Cárcamo, Héctor A; Herle, Carolyn E; Lupwayi, Newton Z

    2015-01-01

    Adults of Sitona lineatus (pea leaf weevil, PLW) feed on foliage of several Fabaceae species but larvae prefer to feed on nodules of Pisum sativum L. and Vicia faba L. Indirectly, through their feeding on rhizobia, weevils can reduce soil and plant available nitrogen (N). However, initial soil N can reduce nodulation and damage by the weevil and reduce control requirements. Understanding these interactions is necessary to make integrated pest management recommendations for PLW. We conducted a greenhouse study to quantify nodulation, soil and plant N content, and nodule damage by weevil larvae in relation to soil N amendment with urea, thiamethoxam insecticide seed coating and crop stage. PLWs reduced the number of older tumescent (multilobed) nodules and thiamethoxam addition increased them regardless of other factors. Nitrogen amendment significantly increased soil available N (>99% nitrate) as expected and PLW presence was associated with significantly lower levels of soil N. PLW decreased plant N content at early flower and thiamethoxam increased it, particularly at late flower. The study illustrated the complexity of interactions that determine insect herbivory effects on plant and soil nutrition for invertebrates that feed on N-fixing root nodules. We conclude that effects of PLW on nodulation and subsequent effects on plant nitrogen are more pronounced during the early growth stages of the plant. This suggests the importance of timing of PLW infestation and may explain the lack of yield depression in relation to this pest observed in many field studies. Also, pea crops in soils with high levels of soil N are unlikely to be affected by this herbivore and should not require insecticide inputs.

  12. Sitona lineatus (Coleoptera: Curculionidae) Larval Feeding on Pisum sativum L. Affects Soil and Plant Nitrogen

    PubMed Central

    Cárcamo, Héctor A.; Herle, Carolyn E.; Lupwayi, Newton Z.

    2015-01-01

    Adults of Sitona lineatus (pea leaf weevil, PLW) feed on foliage of several Fabaceae species but larvae prefer to feed on nodules of Pisum sativum L. and Vicia faba L. Indirectly, through their feeding on rhizobia, weevils can reduce soil and plant available nitrogen (N). However, initial soil N can reduce nodulation and damage by the weevil and reduce control requirements. Understanding these interactions is necessary to make integrated pest management recommendations for PLW. We conducted a greenhouse study to quantify nodulation, soil and plant N content, and nodule damage by weevil larvae in relation to soil N amendment with urea, thiamethoxam insecticide seed coating and crop stage. PLWs reduced the number of older tumescent (multilobed) nodules and thiamethoxam addition increased them regardless of other factors. Nitrogen amendment significantly increased soil available N (>99% nitrate) as expected and PLW presence was associated with significantly lower levels of soil N. PLW decreased plant N content at early flower and thiamethoxam increased it, particularly at late flower. The study illustrated the complexity of interactions that determine insect herbivory effects on plant and soil nutrition for invertebrates that feed on N-fixing root nodules. We conclude that effects of PLW on nodulation and subsequent effects on plant nitrogen are more pronounced during the early growth stages of the plant. This suggests the importance of timing of PLW infestation and may explain the lack of yield depression in relation to this pest observed in many field studies. Also, pea crops in soils with high levels of soil N are unlikely to be affected by this herbivore and should not require insecticide inputs. PMID:26106086

  13. Reduced growth and survival of larval razorback sucker fed selenium-laden zooplankton

    USGS Publications Warehouse

    Hamilton, S.J.; Buhl, K.J.; Bullard, F.A.; McDonald, S.F.

    2005-01-01

    Four groups of larval razorback sucker, an endangered fish, were exposed to selenium-laden zooplankton and survival, growth, and whole-body residues were measured. Studies were conducted with 5, 10, 24, and 28-day-old larvae fed zooplankton collected from six sites adjacent to the Green River, Utah. Water where zooplankton were collected had selenium concentrations ranging from <0.4 to 78 ??g/L, and concentrations in zooplankton ranged from 2.3 to 91 ??g/g dry weight. Static renewal tests were conducted for 20 to 25 days using reference water with selenium concentrations of <1.1 ??g/L. In all studies, 80-100% mortality occurred in 15-20 days. In the 28-day-old larvae, fish weight was significantly reduced 25% in larvae fed zooplankton containing 12 ??g/g selenium. Whole-body concentrations of selenium ranged from 3.7 to 14.3 ??g/g in fish fed zooplankton from the reference site (Sheppard Bottom pond 1) up to 94 ??g/g in fish fed zooplankton from North Roadside Pond. Limited information prior to the studies suggested that the Sheppard pond 1 site was relatively clean and suitable as a reference treatment; however, the nearly complete mortality of larvae and elevated concentrations of selenium in larvae and selenium and other elements in zooplankton indicated that this site was contaminated with selenium and other elements. Selenium concentrations in whole-body larvae and in zooplankton from all sites were close to or greater than toxic thresholds where adverse effects occur in fish. Delayed mortality occurred in larvae fed the two highest selenium concentrations in zooplankton and was thought due to an interaction with other elements. ?? 2004 Elsevier Inc. All rights reserved.

  14. Failure to Burrow and Tunnel Reveals Roles for jim lovell in the Growth and Endoreplication of the Drosophila Larval Tracheae

    PubMed Central

    Qiang, Karen M.; Beckingham, Kathleen M.

    2016-01-01

    The Drosophila protein Jim Lovell (Lov) is a putative transcription factor of the BTB/POZ (Bric- a-Brac/Tramtrack/Broad/ Pox virus and Zinc finger) domain class that is expressed in many elements of the developing larval nervous system. It has roles in innate behaviors such as larval locomotion and adult courtship. In performing tissue-specific knockdown with the Gal4-UAS system we identified a new behavioral phenotype for lov: larvae failed to burrow into their food during their growth phase and then failed to tunnel into an agarose substratum during their wandering phase. We determined that these phenotypes originate in a previously unrecognized role for lov in the tracheae. By using tracheal-specific Gal4 lines, Lov immunolocalization and a lov enhancer trap line, we established that lov is normally expressed in the tracheae from late in embryogenesis through larval life. Using an assay that monitors food burrowing, substrate tunneling and death we showed that lov tracheal knockdown results in tracheal fluid-filling, producing hypoxia that activates the aberrant behaviors and inhibits development. We investigated the role of lov in the tracheae that initiates this sequence of events. We discovered that when lov levels are reduced, the tracheal cells are smaller, more numerous and show lower levels of endopolyploidization. Together our findings indicate that Lov is necessary for tracheal endoreplicative growth and that its loss in this tissue causes loss of tracheal integrity resulting in chronic hypoxia and abnormal burrowing and tunneling behavior. PMID:27494251

  15. Conventional and organic soil fertility management practices affect corn plant nutrition and Ostrinia nubilalis (Lepidoptera: Crambidae) larval performance.

    PubMed

    Murrell, Ebony G; Cullen, Eileen M

    2014-10-01

    Few studies compare how different soil fertilization practices affect plant mineral content and insect performance in organic systems. This study examined: 1) The European corn borer, Ostrinia nubilalis (Hübner), larval response on corn (Zea mays L.) grown in field soils with different soil management histories; and 2) resilience of these plants to O. nubilalis herbivory. Treatments included: 1) standard organic--organically managed soil fertilized with dairy manure and 2 yr of alfalfa (Medicago sativa L.) in the rotation; 2) basic cation saturation ratio--organically managed soil fertilized with dairy manure and alfalfa nitrogen credits, plus addition of gypsum (CaSO4·2H2O) according to the soil balance hypothesis; and 3) conventional--conventionally managed soil fertilized with synthetic fertilizers. Corn plants were reared to maturity in a greenhouse, and then infested with 0-40 O. nubilalis larvae for 17 d. O. nubilalis exhibited negative competitive response to increasing larval densities. Mean development time was significantly faster for larvae consuming basic cation saturation ratio plants than those on standard organic plants, with intermediate development time on conventional plants. Neither total yield (number of kernels) nor proportion kernels damaged differed among soil fertility treatments. Soil nutrients differed significantly in S and in Ca:Mg and Ca:K ratios, but principal components analysis of plant tissue samples taken before O. nubilalis infestation showed that S, Fe, and Cu contributed most to differences in plant nutrient profiles among soil fertility treatments. Results demonstrate that different fertilization regimens can significantly affect insect performance within the context of organic systems, but the effects in this study were relatively minor compared with effects of intraspecific competition.

  16. Field-level validation of a CLIMEX model for Cactoblastis cactorum (Lepidoptera: Pyralidae) using estimated larval growth rates.

    PubMed

    Legaspi, Benjamin C; Legaspi, Jesusa Crisostomo

    2010-04-01

    Invasive pests, such as the cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), have not reached equilibrium distributions and present unique opportunities to validate models by comparing predicted distributions with eventual realized geographic ranges. A CLIMEX model was developed for C. cactorum. Model validation was attempted at the global scale by comparing worldwide distribution against known occurrence records and at the field scale by comparing CLIMEX "growth indices" against field measurements of larval growth. Globally, CLIMEX predicted limited potential distribution in North America (from the Caribbean Islands to Florida, Texas, and Mexico), Africa (South Africa and parts of the eastern coast), southern India, parts of Southeast Asia, and the northeastern coast of Australia. Actual records indicate the moth has been found in the Caribbean (Antigua, Barbuda, Montserrat Saint Kitts and Nevis, Cayman Islands, and U.S. Virgin Islands), Cuba, Bahamas, Puerto Rico, southern Africa, Kenya, Mexico, and Australia. However, the model did not predict that distribution would extend from India to the west into Pakistan. In the United States, comparison of the predicted and actual distribution patterns suggests that the moth may be close to its predicted northern range along the Atlantic coast. Parts of Texas and most of Mexico may be vulnerable to geographic range expansion of C. cactorum. Larval growth rates in the field were estimated by measuring differences in head capsules and body lengths of larval cohorts at weekly intervals. Growth indices plotted against measures of larval growth rates compared poorly when CLIMEX was run using the default historical weather data. CLIMEX predicted a single period conducive to insect development, in contrast to the three generations observed in the field. Only time and more complete records will tell whether C. cactorum will extend its geographical distribution to regions predicted by the CLIMEX model. In terms

  17. Effects of CO2-induced ocean acidification on the growth of the larval olive flounder Paralichthys olivaceus

    NASA Astrophysics Data System (ADS)

    Kim, Kyung-Su; Shim, Jeong Hee; Kim, Suam

    2015-06-01

    It widely thought that ocean acidification processes that caused by atmospheric CO2 increase and accordingly lower seawater pH conditions might cause serious harm to marine food webs in certain ecosystems in the near future. Little is known about how marine fishes respond to reduced pH conditions. We investigated the effects of CO2 conditions on the growth of olive flounder ( Paralichthys olivaceus) larvae. Newly hatched larvae were reared at three different levels of pCO2 (574, 988 and 1297 µatm) in temperature-controlled (21 ± 0.5°C) water tanks for four weeks until metamorphosis. The experiment was repeated three times in May, June, and July 2011, and body lengths and weights were measured at the completion of each experiment. The results indicated that the body length and weight of flounder larvae significantly increased with increasing CO2 concentrations (P < 0.05). A higher daily growth rate during the early larval stage (hatching to 14 days) was found among the larvae reared in low pCO2 conditions, while a significantly lower growth rate was found among larvae in higher pCO2 water conditions. On the other hand, in the late larval stage (18 days after hatching to metamorphosis), the daily growth rate of larvae was much higher in high CO2 water. Bone density of larvae, however, decreased with increasing CO2 concentration in the water

  18. [Larval survival and growth of Arbacia punctulata (Echinodermata: Echinoidea) fed with five micro-algae at two salinities].

    PubMed

    García, Marina; Rosas, Jesús; Hernández, Iván; Velásquez, Aidé; Cabrera, Tomas; Maneiro, Carlos

    2005-12-01

    Fertilized eggs from an spontaneously spawn of thirty sexually mature sea urchins (Arbacia punctulata) were incubated to complete embryonic development. The echinopluteus larvae (3 ind/ml) were distributed into 50 plastic containers (25 containers at 30 psu and 25 containers at 40 psu) and fed on Tetraselmis chuii, Nannochloropsis oculata, Isochrysis galbana, Chaetoceros gracilis and C. calcitrans under a natural photoperiod. The water of the containers was partially renewed (75%) everyday. Larval anatomic development aspects, daily survival and growth were determined. The growth was determined through postoral arms and body length measurement, and body diameter of twelve larvae during metamorphosis. During the planktonic larval phase, only the I. galbana diet produced similar results for both salinities. The relative growth of larvae was isometric (I) for larvae fed on I. galbana at two salinities and positive allometric for those fed on C. gracilis and C. calcitrans at both salinities. In this study A. punctulata started metamorphosis at day 14 and was completed 30 days after fecundation. Significant differences were detected in post-settlement body growth between the two salinities (F = 23.58, p < 0.05): growth was better for larvae at 30 psu (final body diameter was 3.14 +/- 0.44 mm). The final rate of planktonic larvae was highest with I. galbana (58.33%). For juveniles the rate was 6.48% for those fed on C. gracilis (40 psu in both larvae and juveniles). We recommend the use of this diet and 40 psu for survival or 30 psu for growth.

  19. Early Exposure of Bay Scallops (Argopecten irradians) to High CO2 Causes a Decrease in Larval Shell Growth

    PubMed Central

    White, Meredith M.; McCorkle, Daniel C.; Mullineaux, Lauren S.; Cohen, Anne L.

    2013-01-01

    Ocean acidification, characterized by elevated pCO2 and the associated decreases in seawater pH and calcium carbonate saturation state (Ω), has a variable impact on the growth and survival of marine invertebrates. Larval stages are thought to be particularly vulnerable to environmental stressors, and negative impacts of ocean acidification have been seen on fertilization as well as on embryonic, larval, and juvenile development and growth of bivalve molluscs. We investigated the effects of high CO2 exposure (resulting in pH = 7.39, Ωar = 0.74) on the larvae of the bay scallop Argopecten irradians from 12 h to 7 d old, including a switch from high CO2 to ambient CO2 conditions (pH = 7.93, Ωar = 2.26) after 3 d, to assess the possibility of persistent effects of early exposure. The survival of larvae in the high CO2 treatment was consistently lower than the survival of larvae in ambient conditions, and was already significantly lower at 1 d. Likewise, the shell length of larvae in the high CO2 treatment was significantly smaller than larvae in the ambient conditions throughout the experiment and by 7 d, was reduced by 11.5%. This study also demonstrates that the size effects of short-term exposure to high CO2 are still detectable after 7 d of larval development; the shells of larvae exposed to high CO2 for the first 3 d of development and subsequently exposed to ambient CO2 were not significantly different in size at 3 and 7 d than the shells of larvae exposed to high CO2 throughout the experiment. PMID:23596514

  20. Intensity-dependent host mortality: what can it tell us about larval growth strategies in complex life cycle helminths?

    PubMed

    Benesh, D P

    2011-06-01

    Complex life cycle helminths use their intermediate hosts as both a source of nutrients and as transportation. There is an assumed trade-off between these functions in that parasite growth may reduce host survival and thus transmission. The virulence of larval helminths can be assessed by experimentally increasing infection intensities and recording how parasite biomass and host mortality scale with intensity. I summarize the literature on these relationships in larval helminths and I provide an empirical example using the nematode Camallanus lacustris in its copepod first host. In all species studied thus far, including C. lacustris, overall parasite volume increases with intensity. Although a few studies observed host survival to decrease predictably with intensity, several studies found no intensity-dependent mortality or elevated mortality only at extreme intensities. For instance, no intensity-dependent mortality was observed in male copepods infected with C. lacustris, whereas female survival was reduced only at high intensities (>3) and only after worms were fully developed. These observations suggest that at low, natural intensity levels parasites do not exploit intermediate hosts as much as they presumably could and that increased growth would not obviously entail survival costs.

  1. Effects of Dechlorane Plus exposure on axonal growth, musculature and motor behavior in embryo-larval zebrafish.

    PubMed

    Chen, Xiangping; Dong, Qiaoxiang; Chen, Yuanhong; Zhang, Zhenxuan; Huang, Changjiang; Zhu, Yaxian; Zhang, Yong

    2017-03-10

    Developmental neurobehavioral toxicity of Dechlorane Plus (DP) was investigated using the embryo-larval stages of zebrafish (Danio rerio). Normal fertilized embryos were waterborne exposed to DP at 15, 30, 60 μg/L beginning from 6 h post-fertilization (hpf). Larval teratology, motor activity, motoneuron axonal growth and muscle morphology were assessed at different developmental stages. Results showed that DP exposure significantly altered embryonic spontaneous movement, reduced touch-induced movement and free-swimming speed and decreased swimming speed of larvae in response to dark stimulation. These changes occurred at DP doses that resulted no significant teratogenesis in zebrafish. Interestingly, in accord with these behavioral anomalies, DP exposure significantly inhibited axonal growth of primary motoneuron and induced apoptotic cell death and lesions in the muscle fibers of zebrafish. Furthermore, DP exposure at 30 μg/L and 60 μg/L significantly increased reactive oxygen species (ROS) and malondialdehyde (MDA) formation, as well as the mRNA transcript levels of apoptosis-related genes bax and caspase-3. Together, our data indicate that DP induced neurobehavioral deficits may result from combined effects of altered neuronal connectivity and muscle injuries.

  2. GROWTH AND VARIATIONS IN LIPID CLASS AND FATTY ACID COMPOSITION DURING LARVAL DEVELOPMENT OF THE STONE CRAB, MENIPPE ADINA WILLIAMS AND FELDER, 1986

    EPA Science Inventory

    Larval development in decapod crustaceans is marked by variable growth patterns and changes in weight and biochemical composition. Larvae of the stone crab, Menippe adina, were mass-reared under laboratory conditions (28|C; 20o/ooS) from hatching to the megalopal stage. Growth in...

  3. GROWTH AND VARIATIONS IN LIPID CLASS AND FATTY ACID COMPOSITION DURING LARVAL DEVELOPMENT OF THE STONE CRAB, MENIPPE ADINA WILLIAMS AND FELDER, 1986.

    EPA Science Inventory

    Larval development in decapod crustaceans is marked by variable growth patterns and changes in weight and biochemical composition. Larvae of the stone crab, Menippe adina, were mass-reared under laboratory conditions (28?C; 20o/ooS) from hatching to the megalopa stage. Growth in...

  4. Dynamics of Baculovirus Growth and Dispersal in Mamestra brassicae L. (LepidopteraNoctuidae) Larval Populations Introduced into Small Cabbage Plots

    PubMed Central

    Evans, Hugh F.; Allaway, Graham P.

    1983-01-01

    The nuclear polyhedrosis virus of Mamestra brassicae has been studied in larval populations of the moth introduced into small plots of cabbages. Primary dispersal of virus from single foci of infected larvae resulted from enhanced movement of the larvae, which colonized new plants logarithmically. Virus growth within the host population was quantified, and infection of young larvae in the following generation was related directly to the concentration of virus produced during the primary phase. Secondary cycling of virus resulted in dispersal of inoculum from multiple foci, and a large proportion of plants were ultimately colonized by infected larvae. The dynamics of virus growth during secondary dispersal were quantified and contrasted with results from the primary phase. The significance of these results is discussed in relation to possible control of insect pests through dispersal of virus by the host insect. PMID:16346197

  5. Larval Exposure to Chlorpyrifos Affects Nutritional Physiology and Induces Genotoxicity in Silkworm Philosamia ricini (Lepidoptera: Saturniidae)

    PubMed Central

    Kalita, Moni K.; Haloi, Kishor; Devi, Dipali

    2016-01-01

    Chlorpyrifos is a most widely used organophosphate insecticide because of its cost effectiveness and degradable nature. However, this pesticide enters and contaminates the environment either by direct application, spray drifts or crop run off and shows adverse effect on the non-targeted organisms. Philosamia ricini (eri silkworm), one of the most exploited, domesticated and commercialized non mulberry silkworm is known for mass production of eri silk. The silkworm larvae get exposed to pesticide residues on the leaves of food plants. The present study investigates the effect of commercial formulation of chlorpyrifos (Pyrifos-20 EC) on eri silkworm. Initially the LC50 value of chlorpyrifos was determined at 24–96 h and further experiments were carried out with sub lethal concentrations of the chlorpyrifos after 24 h of exposure period. The potential toxicity of chlorpyrifos was evaluated as a fuction of metabolism and nutritional physiology in 3rd, 4th, and 5th instar larvae. Alteration in histoarchitecture of 5th instar eri silkworm gut exposed to sub lethal concentration of chlorpyrifos formulation was also studied. Chlorpyrifos induced genotoxicity in silkworm hemocytes was also investigated by single cell gel electrophoresis, micronuclei assay, and apoptosis assay. Herein, LC50 values of chlorpyrifos were calculated as 3.83, 3.35, 2.68, and 2.35 mg/L at 24, 48, 72, and 96h respectively. A significant decrease in trehalose activity along with digestive enzyme activity was observed in chlorpyrifos affected groups (P < 0.05). Further, genotoxicity study revealed higher tail percentage, tail length and tail moment of the damage DNA in chlorpyrifos exposed groups (P < 0.001). Moreover, at 2.0 mg/L concentration, ~10 fold increases in tail length was observed as compared to the control. Results showed activation of caspase activity following 24 h chlorpyrifos exposure (1.5 and 2.0 mg/L) in a dose-dependent manner. Moreover, in control group less number of apoptotic

  6. Larval Exposure to Chlorpyrifos Affects Nutritional Physiology and Induces Genotoxicity in Silkworm Philosamia ricini (Lepidoptera: Saturniidae).

    PubMed

    Kalita, Moni K; Haloi, Kishor; Devi, Dipali

    2016-01-01

    Chlorpyrifos is a most widely used organophosphate insecticide because of its cost effectiveness and degradable nature. However, this pesticide enters and contaminates the environment either by direct application, spray drifts or crop run off and shows adverse effect on the non-targeted organisms. Philosamia ricini (eri silkworm), one of the most exploited, domesticated and commercialized non mulberry silkworm is known for mass production of eri silk. The silkworm larvae get exposed to pesticide residues on the leaves of food plants. The present study investigates the effect of commercial formulation of chlorpyrifos (Pyrifos-20 EC) on eri silkworm. Initially the LC50 value of chlorpyrifos was determined at 24-96 h and further experiments were carried out with sub lethal concentrations of the chlorpyrifos after 24 h of exposure period. The potential toxicity of chlorpyrifos was evaluated as a fuction of metabolism and nutritional physiology in 3rd, 4th, and 5th instar larvae. Alteration in histoarchitecture of 5th instar eri silkworm gut exposed to sub lethal concentration of chlorpyrifos formulation was also studied. Chlorpyrifos induced genotoxicity in silkworm hemocytes was also investigated by single cell gel electrophoresis, micronuclei assay, and apoptosis assay. Herein, LC50 values of chlorpyrifos were calculated as 3.83, 3.35, 2.68, and 2.35 mg/L at 24, 48, 72, and 96h respectively. A significant decrease in trehalose activity along with digestive enzyme activity was observed in chlorpyrifos affected groups (P < 0.05). Further, genotoxicity study revealed higher tail percentage, tail length and tail moment of the damage DNA in chlorpyrifos exposed groups (P < 0.001). Moreover, at 2.0 mg/L concentration, ~10 fold increases in tail length was observed as compared to the control. Results showed activation of caspase activity following 24 h chlorpyrifos exposure (1.5 and 2.0 mg/L) in a dose-dependent manner. Moreover, in control group less number of apoptotic

  7. Patterns of growth and tract formation during the early development of secondary lineages in the Drosophila larval brain.

    PubMed

    Lovick, Jennifer K; Kong, Angel; Omoto, Jaison J; Ngo, Kathy T; Younossi-Hartenstein, Amelia; Hartenstein, Volker

    2016-04-01

    The Drosophila brain consists of a relatively small number of invariant, genetically determined lineages which provide a model to study the relationship between gene function and neuronal architecture. In following this long-term goal, we reconstruct the morphology (projection pattern and connectivity) and gene expression patterns of brain lineages throughout development. In this article, we focus on the secondary phase of lineage morphogenesis, from the reactivation of neuroblast proliferation in the first larval instar to the time when proliferation ends and secondary axon tracts have fully extended in the late third larval instar. We have reconstructed the location and projection of secondary lineages at close (4 h) intervals and produced a detailed map in the form of confocal z-projections and digital three-dimensional models of all lineages at successive larval stages. Based on these reconstructions, we could compare the spatio-temporal pattern of axon formation and morphogenetic movements of different lineages in normal brain development. In addition to wild type, we reconstructed lineage morphology in two mutant conditions. (1) Expressing the construct UAS-p35 which rescues programmed cell death we could systematically determine which lineages normally lose hemilineages to apoptosis. (2) so-Gal4-driven expression of dominant-negative EGFR ablated the optic lobe, which allowed us to conclude that the global centrifugal movement normally affecting the cell bodies of lateral lineages in the late larva is causally related to the expansion of the optic lobe, and that the central pattern of axonal projections of these lineages is independent of the presence or absence of the optic lobe.

  8. Patterns of growth and tract formation during the early development of secondary lineages in the Drosophila larval brain

    PubMed Central

    Lovick, Jennifer K.; Kong, Angel; Omoto, Jaison J.; Ngo, Kathy T.; Younossi-Hartenstein, Amelia; Hartenstein, Volker

    2015-01-01

    The Drosophila brain consists of a relatively small number of invariant, genetically determined lineages which provide a model to study the relationship between gene function and neuronal architecture. In following this long-term goal we reconstruct the morphology (projection pattern and connectivity) and gene expression patterns of brain lineages throughout development. In the present paper, we focus on the secondary phase of lineage morphogenesis, from the reactivation of neuroblast proliferation in the first larval instar to the time when proliferation ends and secondary axon tracts have fully extended in the late third larval instar. We have reconstructed the location and projection of secondary lineages at close (4h) intervals and produced a detailed map in the form of confocal z-projections and digital 3D models of all lineages at successive larval stages. Based on these reconstructions we could compare the spatio-temporal pattern of axon formation and morphogenetic movements of different lineages in normal brain development. In addition to wild type, we reconstructed lineage morphology in two mutant conditions. (1) Expressing the construct UAS-p35 which rescues programmed cell death we could systematically determine which lineages normally lose hemilineages to apoptosis. (2) so-Gal4-driven expression of dominant-negative EGFR ablated the optic lobe, which allowed us to conclude that the global centrifugal movement normally affecting the cell bodies of lateral lineages in the late larva is causally related to the expansion of the optic lobe, and that the central pattern of axonal projections of these lineages is independent of the presence or absence of the optic lobe. PMID:26178322

  9. Effects of the herbicide atrazine on Ambystoma tigrinum metamorphosis: duration, larval growth, and hormonal response

    USGS Publications Warehouse

    Larson, Diane L.; McDonald, Susan; Hamilton, Steven J.; Fivizzani, Albert J.; Newton, Wesley E.

    1998-01-01

    We exposed larval tiger salamanders (Ambystoma tigrinum) reared in the laboratory from eggs collected from a prairie wetland in North Dakota to three concentrations of atrazine (0, 75, and 250 i??g/L) in a static renewal test to determine the pesticide's effect on (1) plasma corticosterone and thyroxine concentrations, (2) larval size, and (3) days-to-stage at stages 2 and 4 of metamorphic climax. We found significant effects of atrazine on each of these response variables. Plasma thyroxine was elevated in both atrazine-exposed groups compared to the control group; plasma corticosterone was depressed in the 75 i??g/L treatment compared with both the control and 250 i??g/L treatment. Larvae exposed to 75 i??g/L atrazine reached stage 4 later, but at a size and weight comparable to the control group. By contrast, larvae in the 250 i??g/L treatment progressed to stage 4 at the same time but at a smaller size and lower weight than larvae in the control group. These results indicate that the herbicide has the potential to influence tiger salamander life history. We present a model consistent with our results, whereby corticosterone and thyroxine interact to regulate metamorphosis of tiger salamanders based on nutrient assimilation and adult fitness

  10. EVALUATION OF THE ROBUSTNESS OF THE FATHEAD MINNOW, PIMEPHALES PROMELAS, LARVAL SURVIVAL AND GROWTH TEST, U.S. EPA METHOD 1000.0

    EPA Science Inventory

    An intralaboratory study was conducted to evaluate the robustness of the Fathead Minnow (Pimephales promelas) Larval Survival and Growth Test, Method 1000.0 Toxicity tests were conducted with the reference toxicants hexavalent chromium (Cr6+) and copper (Cu), and the data were st...

  11. Development of the larval amphibian growth and development assay: Effects of benzophenone-2 exposure in Xenopus laevis from embryo to juvenile

    EPA Science Inventory

    The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized chemical testing guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan’s Ministry of Environment to support risk assessment. The assay is employed as a ...

  12. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua).

    PubMed

    Nedelec, Sophie L; Simpson, Stephen D; Morley, Erica L; Nedelec, Brendan; Radford, Andrew N

    2015-10-22

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width-length ratios. Larvae with lower body width-length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures.

  13. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua)

    PubMed Central

    Nedelec, Sophie L.; Simpson, Stephen D.; Morley, Erica L.; Nedelec, Brendan; Radford, Andrew N.

    2015-01-01

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width–length ratios. Larvae with lower body width–length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures. PMID:26468248

  14. Effects of past, present, and future ocean carbon dioxide concentrations on the growth and survival of larval shellfish

    PubMed Central

    Gobler, Christopher J.

    2010-01-01

    The combustion of fossil fuels has enriched levels of CO2 in the world’s oceans and decreased ocean pH. Although the continuation of these processes may alter the growth, survival, and diversity of marine organisms that synthesize CaCO3 shells, the effects of ocean acidification since the dawn of the industrial revolution are not clear. Here we present experiments that examined the effects of the ocean’s past, present, and future (21st and 22nd centuries) CO2 concentrations on the growth, survival, and condition of larvae of two species of commercially and ecologically valuable bivalve shellfish (Mercenaria mercenaria and Argopecten irradians). Larvae grown under near preindustrial CO2 concentrations (250 ppm) displayed significantly faster growth and metamorphosis as well as higher survival and lipid accumulation rates compared with individuals reared under modern day CO2 levels. Bivalves grown under near preindustrial CO2 levels displayed thicker, more robust shells than individuals grown at present CO2 concentrations, whereas bivalves exposed to CO2 levels expected later this century had shells that were malformed and eroded. These results suggest that the ocean acidification that has occurred during the past two centuries may be inhibiting the development and survival of larval shellfish and contributing to global declines of some bivalve populations. PMID:20855590

  15. Larval growth in polyphenic salamanders: making the best of a bad lot.

    PubMed

    Whiteman, H H; Wissinger, S A; Denoël, M; Mecklin, C J; Gerlanc, N M; Gutrich, J J

    2012-01-01

    Polyphenisms are excellent models for studying phenotypic variation, yet few studies have focused on natural populations. Facultative paedomorphosis is a polyphenism in which salamanders either metamorphose or retain their larval morphology and eventually become paedomorphic. Paedomorphosis can result from selection for capitalizing on favorable aquatic habitats (paedomorph advantage), but could also be a default strategy under poor aquatic conditions (best of a bad lot). We tested these alternatives by quantifying how the developmental environment influences the ontogeny of wild Arizona tiger salamanders (Ambystoma tigrinum nebulosum). Most paedomorphs in our study population arose from slow-growing larvae that developed under high density and size-structured conditions (best of a bad lot), although a few faster-growing larvae also became paedomorphic (paedomorph advantage). Males were more likely to become paedomorphs than females and did so under a greater range of body sizes than females, signifying a critical role for gender in this polyphenism. Our results emphasize that the same phenotype can be adaptive under different environmental and genetic contexts and that studies of phenotypic variation should consider multiple mechanisms of morph production.

  16. Novel growth media for rearing larval horn flies, Haematobia irritans (Diptera: Muscidae).

    PubMed

    Perotti, M A; Lysyk, T J

    2003-01-01

    Experiments were conducted to develop an agar-based medium for rearing immature horn flies, Hematobia irritans (L.). Larval survival was determined on sterilized manure inoculated with pure and mixed cultures of Acinetobacter sp., Bacillus pumilus Meyer & Gottheil, Comamonas acidovorans den Dooren de Jong, Pseudomonas mendocina Palleroni, Flavobacterium sp. and Empedobacter breve (Holmes & Owen). Rearing larvae on mixed cultures enhanced pupal weight but not survival. Horn fly larvae failed to survive when reared on standard bacteriological media inoculated with pure and mixed cultures of Acinetobacter sp., P. mendocina, and C. acidovorans. Larvae completed development on a minimal medium supplemented with alfalfa, egg proteins, and vitamins. Medium with low alfalfa content (30 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with egg yolk protein and vitamins. Medium with high alfalfa content (130 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with whole egg protein and vitamins. Survival was also favored when media were inoculated with pure cultures of Acinetobacter or Acinetobacter mixed with either Pseudomonas or Comamonas. Individual plates could support larvae developing from up to 40 eggs, and survival was least variable when plates were inoculated with greater numbers of eggs. This rearing system shows promise as a means for conducting standardized bioassays on a meridic diet.

  17. Diet and density dependent competition affect larval performance and oviposition site selection in the mosquito species Aedes albopictus (Diptera: Culicidae)

    PubMed Central

    2012-01-01

    Background Oviposition-site choice is an essential component of the life history of all mosquito species. According to the oviposition-preference offspring-performance (P-P) hypothesis, if optimizing offspring performance and fitness ensures high overall reproductive fitness for a given species, the female should accurately assess details of the heterogeneous environment and lay her eggs preferentially in sites with conditions more suitable to offspring. Methods We empirically tested the P-P hypothesis using the mosquito species Aedes albopictus by artificially manipulating two habitat conditions: diet (measured as mg of food added to a container) and conspecific density (CD; number of pre-existing larvae of the same species). Immature development (larval mortality, development time to pupation and time to emergence) and fitness (measured as wing length) were monitored from first instar through adult emergence using a factorial experimental design over two ascending gradients of diet (2.0, 3.6, 7.2 and 20 mg food/300 ml water) and CD (0, 20, 40 and 80 larvae/300 ml water). Treatments that exerted the most contrasting values of larval performance were recreated in a second experiment consisting of single-female oviposition site selection assay. Results Development time decreased as food concentration increased, except from 7.2 mg to 20.0 mg (Two-Way CR ANOVA Post-Hoc test, P > 0.1). Development time decreased also as conspecific density increased from zero to 80 larvae (Two-Way CR ANOVA Post-Hoc test, P < 0.5). Combined, these results support the role of density-dependent competition for resources as a limiting factor for mosquito larval performance. Oviposition assays indicated that female mosquitoes select for larval habitats with conspecifics and that larval density was more important than diet in driving selection for oviposition sites. Conclusions This study supports predictions of the P-P hypothesis and provides a mechanistic understanding of the

  18. VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB(R))

    EPA Science Inventory

    This study examines the effects of fenoxycarb?, an insect juvenile hormone (JH) analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations fr...

  19. Nitric oxide affects ERK signaling through down-regulation of MAP kinase phosphatase levels during larval development of the ascidian Ciona intestinalis.

    PubMed

    Castellano, Immacolata; Ercolesi, Elena; Palumbo, Anna

    2014-01-01

    In the ascidian Ciona intestinalis larval development and metamorphosis require a complex interplay of events, including nitric oxide (NO) production, MAP kinases (ERK, JNK) and caspase-3 activation. We have previously shown that NO levels affect the rate of metamorphosis, regulate caspase activity and promote an oxidative stress pathway, resulting in protein nitration. Here, we report that NO down-regulates MAP kinase phosphatases (mkps) expression affecting positively ERK signaling. By pharmacological approach, we observed that the reduction of endogenous NO levels caused a decrease of ERK phosphorylation, whereas increasing levels of NO induced ERK activation. We have also identified the ERK gene network affected by NO, including mpk1, mpk3 and some key developmental genes by quantitative gene expression analysis. We demonstrate that NO induces an ERK-independent down-regulation of mkp1 and mkp3, responsible for maintaining the ERK phosphorylation levels necessary for transcription of key metamorphic genes, such as the hormone receptor rev-erb and the van willebrand protein vwa1c. These results add new insights into the role played by NO during larval development and metamorphosis in Ciona, highlighting the cross-talk between different signaling pathways.

  20. An age-size reaction norm yields insight into environmental interactions affecting life-history traits: a factorial study of larval development in the malaria mosquito Anopheles gambiae sensu stricto.

    PubMed

    Phelan, Conan; Rotiberg, Bernard D

    2013-07-01

    Environmental factors frequently act nonindependently to determine growth and development of insects. Because age and size at maturity strongly influence population dynamics, interaction effects among environmental variables complicate the task of predicting dynamics of insect populations under novel conditions. We reared larvae of the African malaria mosquito Anopheles gambiae sensu stricto (s.s.) under three factors relevant to changes in climate and land use: food level, water depth, and temperature. Each factor was held at two levels in a fully crossed design, for eight experimental treatments. Larval survival, larval development time, and adult size (wing length) were measured to indicate the importance of interaction effects upon population-level processes. For age and size at emergence, but not survival, significant interaction effects were detected for all three factors, in addition to sex. Some of these interaction effects can be understood as consequences of how the different factors influence energy usage in the context of a nonindependent relationship between age and size. Experimentally assessing interaction effects for all potential future sets of conditions is intractable. However, considering how different factors affect energy usage within the context of an insect's evolved developmental program can provide insight into the causes of complex environmental effects on populations.

  1. Interrenal and thyroid development in red drum (Sciaenops ocellatus): effects of nursery environment on larval growth and cortisol concentration during settlement.

    PubMed

    Pérez-Domínguez, Rafael; Holt, G Joan

    2006-04-01

    Red drum settle into shallow seagrass meadows during the larval stage. Day-night cycles in these habitats result in marked diel temperature and dissolved oxygen (DO) cycles, and it is possible that extreme fluctuations influence endocrine development and growth of larvae. Here, we described red drum interrenal and thyroid ontogeny and determine responses to environmental stimuli with special emphasis on settlement to explore possible role of hormones as mediator of directive environmental factors. This study detected an early activation of thyroid and interrenal axis during the yolk-sac phase and a second activation of the thyroid starting at settlement size to the end of the larval period. Whole-body l-thyroxine (T4) and 3-5-3'-triiodo-l-thyronine (T3) showed a sharp decline at the juvenile stage. In contrast, cortisol steadily declines during the larval phase to a minimum before the end of the larval period. Older settlement-size larvae exposed to a strong stimulus increased whole body cortisol. In contrast, new settlers showed a minor cortisol rise suggesting changes on stress responsiveness during the ontogeny of the species. Additionally, settlement-size larvae exposed to various environmentally realistic temperature or DO fluctuations showed no difference in growth compared to fish grown under stable conditions (control). However, growth rate was significantly reduced in DO cycled fish with prolonged exposure to hypoxia. No differences were found in whole-body cortisol levels in the reduced growth treatment groups, suggesting that growth retardation was not related to a cortisol-mediated stress response. In moderate DO and temperature treatment groups, cortisol showed wider fluctuations than control groups during the night time that were not related to stress.

  2. UPRT, a suicide-gene therapy candidate in higher eukaryotes, is required for Drosophila larval growth and normal adult lifespan

    PubMed Central

    Ghosh, Arpan C.; Shimell, MaryJane; Leof, Emma R.; Haley, Macy J.; O’Connor, Michael B.

    2015-01-01

    Uracil phosphoribosyltransferase (UPRT) is a pyrimidine salvage pathway enzyme that catalyzes the conversion of uracil to uridine monophosphate (UMP). The enzyme is highly conserved from prokaryotes to humans and yet phylogenetic evidence suggests that UPRT homologues from higher-eukaryotes, including Drosophila, are incapable of binding uracil. Purified human UPRT also do not show any enzymatic activity in vitro, making microbial UPRT an attractive candidate for anti-microbial drug development, suicide-gene therapy, and cell-specific mRNA labeling techniques. Nevertheless, the enzymatic site of UPRT remains conserved across the animal kingdom indicating an in vivo role for the enzyme. We find that the Drosophila UPRT homologue, krishah (kri), codes for an enzyme that is required for larval growth, pre-pupal/pupal viability and long-term adult lifespan. Our findings suggest that UPRT from all higher eukaryotes is likely enzymatically active in vivo and challenges the previous notion that the enzyme is non-essential in higher eukaryotes and cautions against targeting the enzyme for therapeutic purposes. Our findings also suggest that expression of the endogenous UPRT gene will likely cause background incorporation when using microbial UPRT as a cell-specific mRNA labeling reagent in higher eukaryotes. PMID:26271729

  3. Silencing the HaAK gene by transgenic plant-mediated RNAi impairs larval growth of Helicoverpa armigera.

    PubMed

    Liu, Feng; Wang, Xiao-Dong; Zhao, Yi-Ying; Li, Yan-Jun; Liu, Yong-Chang; Sun, Jie

    2015-01-01

    Insect pests have caused noticeable economic losses in agriculture, and the heavy use of insecticide to control pests not only brings the threats of insecticide resistance but also causes the great pollution to foods and the environment. Transgenic plants producing double-stranded RNA (dsRNA) directed against insect genes have been is currently developed for protection against insect pests. In this study, we used this technology to silence the arginine kinase (AK) gene of Helicoverpa armigera (HaAK), encoding a phosphotransferase that plays a critical role in cellular energy metabolism in invertebrate. Transgenic Arabidopsis plants producing HaAK dsRNA were generated by Agrobacterium-mediated transformation. The maximal mortality rate of 55% was reached when H. armigera first-instar larvae were fed with transgenic plant leaves for 3 days, which was dramatically higher than the 18% mortality recorded in the control group. Moreover, the ingestion of transgenic plants significantly retarded larval growth, and the transcript levels of HaAK were also knocked down by up to 52%. The feeding bioassays further indicated that the inhibition efficiency was correlated with the integrity and concentration of the produced HaAK dsRNA in transgenic plants. These results strongly show that the resistance to H. armigera was improved in transgenic Arabidopsis plants, suggesting that the RNAi targeting of AK has the potential for the control of insect pests.

  4. Larval Helicoverpa zea Transcriptional, Growth and Behavioral Responses to Nicotine and Nicotiana tabacum

    PubMed Central

    Gog, Linus; Vogel, Heiko; Hum-Musser, Sue M.; Tuter, Jason; Musser, Richard O.

    2014-01-01

    The polyphagous feeding habits of the corn earworm, Helicoverpa zea (Boddie), underscore its status as a major agricultural pest with a wide geographic distribution and host plant repertoire. To study the transcriptomic response to toxins in diet, we conducted a microarray analysis of H. zea caterpillars feeding on artificial diet, diet laced with nicotine and Nicotiana tabacum (L.) plants. We supplemented our analysis with growth and aversion bioassays. The transcriptome reflects an abundant expression of proteases, chitin, cytochrome P450 and immune-related genes, many of which are shared between the two experimental treatments. However, the tobacco treatment tended to elicit stronger transcriptional responses than nicotine-laced diet. The salivary factor glucose oxidase, known to suppress nicotine induction in the plant, was upregulated by H. zea in response to tobacco but not to nicotine-laced diet. Reduced caterpillar growth rates accompanied the broad regulation of genes associated with growth, such as juvenile hormone epoxide hydrolase. The differential expression of chemosensory proteins, such as odorant binding-protein-2 precursor, as well as the neurotransmitter nicotinic-acetylcholine-receptor subunit 9, highlights candidate genes regulating aversive behavior towards nicotine. We suggest that an observed coincidental rise in cannibalistic behavior and regulation of proteases and protease inhibitors in H. zea larvae signify a compensatory response to induced plant defenses. PMID:26462833

  5. Plastic Hatching Timing by Red-Eyed Treefrog Embryos Interacts with Larval Predator Identity and Sublethal Predation to Affect Prey Morphology but Not Performance

    PubMed Central

    Touchon, Justin C.; Wojdak, Jeremy M.

    2014-01-01

    Many animals respond to predation risk by altering their morphology, behavior, or life-history. We know a great deal about the cues prey respond to and the changes to prey that can be induced by predation risk, but less is known about how plastic responses to predators may be affected by separate plastic responses occurring earlier in life, particularly during the embryonic period. Embryos of a broad array of taxa can respond to egg- or larval-stage risks by altering hatching timing, which may alter the way organisms respond to future predators. Using the red-eyed treefrog (Agalychnis callidryas), a model for understanding the effects of plasticity across life-stages, we assessed how the combined effects of induced variation in the timing of embryo hatching and variation in the larval predator community impacted tadpole morphology, pigmentation and swimming performance. We found that A. callidryas tadpoles developed deeper tail muscles and fins and darker pigmentation in response to fish predators, either when alone or in diverse community with other predators. Tadpoles altered morphology much less so to dragonfly naiads or water bugs. Interestingly, morphological responses to predators were also affected by induced differences in hatching age, with early and late-hatched tadpoles exhibiting different allometric relationships between tail height and body length in different predator environments. Beyond induced morphological changes, fish predators often damaged tadpoles’ tails without killing them (i.e., sublethal predation), but these tadpoles swam equally quickly to those with fully intact tails. This was due to the fact that tadpoles with more damaged tails increased tail beats to achieve equal swimming speed. This study demonstrates that plastic phenotypic responses to predation risk can be influenced by a complex combination of responses to both the embryo and larval environments, but also that prey performance can be highly resilient to sublethal predation

  6. Torso, a Drosophila receptor tyrosine kinase, plays a novel role in the larval fat body in regulating insulin signaling and body growth.

    PubMed

    Jun, Jong Woo; Han, Gangsik; Yun, Hyun Myoung; Lee, Gang Jun; Hyun, Seogang

    2016-08-01

    Torso is a receptor tyrosine kinase whose localized activation at the termini of the Drosophila embryo is mediated by its ligand, Trunk. Recent studies have unveiled a second function of Torso in the larval prothoracic gland (PG) as the receptor for the prothoracicotropic hormone, which triggers pupariation. As such, inhibition of Torso in the PG prolongs the larval growth period, thereby increasing the final pupa size. Here, we report that Torso also acts in the larval fat body, regulating body size in a manner opposite from that of Torso in PG. We confirmed the expression of torso mRNA in the larval fat body and its reduction by RNA interference (RNAi). Fat body-specific knockdown of torso, by either of the two independent RNAi transgenes, significantly decreased the final pupal size. We found that torso knockdown suppresses insulin/target of rapamycin (TOR) signaling in the fat body, as confirmed by repression of Akt and S6K. Notably, the decrease in insulin/TOR signaling and decrease of pupal size induced by the knockdown of torso were rescued by the expression of a constitutively active form of the insulin receptor or by the knockdown of FOXO. Our study revealed a novel role for Torso in the fat body with respect to regulation of insulin/TOR signaling and body size. This finding exemplifies the contrasting effects of the same gene expressed in two different organs on organismal physiology.

  7. Too low to kill: concentration of the secondary metabolite ranunculin in buttercup pollen does not affect bee larval survival.

    PubMed

    Sedivy, Claudio; Piskorski, Rafal; Müller, Andreas; Dorn, Silvia

    2012-08-01

    Growing evidence suggests that the freely accessible pollen of some plants is chemically protected against pollen-feeding flower visitors. For example, a diet of pollen from buttercup plants (Ranunculus) recently was shown to have a deleterious effect on developing larvae of several bee species not specialized on Ranunculus. Numerous Ranunculus species contain ranunculin, the glucosyl hydrate form of the highly reactive and toxic lactone protoanemonin, that causes the toxicity of these plants. We tested whether the presence of ranunculin is responsible for the lethal effects of R. acris pollen on the larvae of two bee species that are not Ranunculus specialists. To investigate the effect on bee larval development, we added ranunculin to the pollen provisions of the Campanula specialist bee Chelostoma rapunculi and the Asteraceae specialist bee Heriades truncorum, and allowed the larvae to feed on these provisions. We quantified ranunculin in pollen of R. acris and in brood cell provisions collected by the Ranunculus specialist bee Chelostoma florisomne. We demonstrated that although ranunculin was lethal to both tested bee species in high concentrations, the concentration in the pollen of R. acris was at least fourfold lower than that tolerated by the larvae of C. rapunculi and H. truncorum in the feeding experiments. Ranunculin concentration in the brood cells of C. florisomne was on average even twentyfold lower than that in Ranunculus pollen, suggesting that a mechanism different from ranunculin intoxication accounts for the larval mortality reported for bees not specialized on Ranunculus pollen.

  8. Tree holes as larval habitats for Aedes aegypti in urban, suburban and forest habitats in a dengue affected area.

    PubMed

    Mangudo, C; Aparicio, J P; Gleiser, R M

    2015-12-01

    Aedes aegypti (L.) (Diptera: Culicidae), the main vector of dengue and urban yellow fever in the world, is highly adapted to the human environment. Artificial containers are the most common larval habitat for the species, but it may develop in tree holes and other phytotelmata. This study assessed whether tree holes in San Ramón de la Nueva Orán, a city located in subtropical montane moist forest where dengue outbreaks occur, are relevant as larval habitat for Ae. aegypti and if the species may be found in natural areas far from human habitations. Water holding tree holes were sampled during 3 years once a month along the rainy season using a siphon bottle, in urban and suburban sites within the city and in adjacent forested areas. Larvae and pupae were collected and the presence and volume of water in each tree hole were recorded. Finding Ae. aegypti in forested areas was an isolated event; however, the species was frequently collected from tree holes throughout the city and along the sampling period. Moreover, larvae were collected in considerably high numbers, stressing the importance of taking into account these natural cavities as potential reinfestation foci within dengue control framework.

  9. Pelagic larval duration and settlement size of a reef fish are spatially consistent, but post-settlement growth varies at the reef scale

    NASA Astrophysics Data System (ADS)

    Leahy, Susannah M.; Russ, Garry R.; Abesamis, Rene A.

    2015-12-01

    Recent research has demonstrated that, despite a pelagic larval stage, many coral reef fishes disperse over relatively small distances, leading to well-connected populations on scales of 0-30 km. Although variation in key biological characteristics has been explored on the scale of 100-1000 s of km, it has rarely been explored at the scale relevant to actual larval dispersal and population connectivity on ecological timescales. In this study, we surveyed the habitat and collected specimens ( n = 447) of juvenile butterflyfish, Chaetodon vagabundus, at nine sites along an 80-km stretch of coastline in the central Philippines to identify variation in key life history parameters at a spatial scale relevant to population connectivity. Mean pelagic larval duration (PLD) was 24.03 d (SE = 0.16 d), and settlement size was estimated to be 20.54 mm total length (TL; SE = 0.61 mm). Both traits were spatially consistent, although this PLD is considerably shorter than that reported elsewhere. In contrast, post-settlement daily growth rates, calculated from otolith increment widths from 1 to 50 d post-settlement, varied strongly across the study region. Elevated growth rates were associated with rocky habitats that this species is known to recruit to, but were strongly negatively correlated with macroalgal cover and exhibited negative density dependence with conspecific juveniles. Larger animals had lower early (first 50 d post-settlement) growth rates than smaller animals, even after accounting for seasonal variation in growth rates. Both VBGF and Gompertz models provided good fits to post-settlement size-at-age data ( n = 447 fish), but the VBGF's estimate of asymptotic length ( L ∞ = 168 mm) was more consistent with field observations of maximum fish length. Our findings indicate that larval characteristics are consistent at the spatial scale at which populations are likely well connected, but that site-level biological differences develop post-settlement, most likely as a

  10. Spatial and temporal heterogeneity of Larval Shad in a large impoundment

    SciTech Connect

    Allen, M.S.; DeVries, D.R. )

    1993-11-01

    Factors that affect recruitment of threadfin shad Dorosoma petenense and gizzard shad D. cepedianum, two important prey species in southern reservoirs, are not well understood. Larval shad typically have not been identified to species, though interactions between shad larvae likely affect their recruitment and that of their predators. Using myomere counts to identify larval shad to species, the authors quantified spatial and temporal variation in species distributions in West Point Reservoir, Alabama-Georgia. They sampled larvae every 3-4 at three distances from shore (inshore and 25 and 50 m offshore) at each of three sites. Larval threadfin shad migrated offshore in all three sites, whereas larval gizzard shad were evenly distributed across distances from shore. Because of these movement differences, larval gizzard shad and larval threadfin shad may encounter different habitat-specific predation rates, climatic effects, and food availability. In addition, larval gizzard shad were present before larval threadfin shad and grew beyond the size vulnerable to our capture techniques before threadfin shad abundance peaked. If zooplankton densities are reduced by young-of-year shad, as documented in other systems, later-hatched threadfin shad would encounter fewer zooplankton than were available to the earlier larval gizzard shad. Threadfin shad would have reduced growth and greater vulnerability to predation and starvation. 36 refs., 8 figs., 2 tabs.

  11. D-ribose competitively reverses inhibition by D-psicose of larval growth in Caenorhabditis elegans.

    PubMed

    Sato, Masashi; Yokoi, Nobutoshi; Kurose, Hiroyuki; Yamasaki, Toru

    2009-05-01

    D-Psicose inhibits the growth of L1 stage Caenorhabditis elegans. Sugars, involved in the pentose phosphate pathway, were examined for their ability to reverse the inhibition. Among these sugars, D-ribose specifically exerted reversing activity in a competitive manner. The ingested sugars are probably phosphorylated, although it remains to be seen whether D-psicose is phosphorylated. The structural similarity of D-psicofuranose 6-phosphate (Pf6P) or D-psicofuranose (Pf) to D-ribofuranose 5-phosphate (Rf5P) suggests that Pf6P or Pf is reversibly docked in the active site(s) of ribose-5-phosphate isomerase(s) to act as an antimetabolite to Rf5P, leading to inhibition of the biosynthesis of nucleic acids. D-Psicose was much less potent against the L4 stage than against the L1 stage. This is probably because in the L4 stage the somatic cell lineages come to an end and the number of germ-line nuclei increases to about 1000.

  12. Growth and apoptosis during larval forelimb development and adult forelimb regeneration in the newt ( Notophthalmus viridescens).

    PubMed

    Vlaskalin, Tatjana; Wong, Christine J; Tsilfidis, Catherine

    2004-09-01

    Many of the genes involved in the initial development of the limb in higher vertebrates are also expressed during regeneration of the limb in urodeles such as Notophthalmus viridescens. These similarities have led researchers to conclude that the regeneration process is a recapitulation of development, and that patterning of the regenerate mimics pattern formation in development. However, the developing limb and the regenerating limb do not look similar. In developing urodele forelimbs, digits appear sequentially as outgrowths from the limb palette. In regeneration, all the digits appear at once. In this work, we address the issue of whether regeneration and development are similar by examining growth and apoptosis patterns. In contrast to higher vertebrates, forelimb development in the newt, N. viridescens, does not use interdigital apoptosis as the method of digit separation. During adult forelimb regeneration, apoptosis seems to play an important role in wound healing and again during cartilage to bone turnover in the advanced digits and radius/ulna. However, similar to forelimb development, demarcation of the digits in adult forelimb regeneration does not involve interdigital apoptosis. Outgrowth, rather than regression of the interdigital mesenchyme, leads to the individualization of forelimb digits in both newt development and regeneration.

  13. Otolith development in larval and juvenile Schizothorax davidi: ontogeny and growth increment characteristics

    NASA Astrophysics Data System (ADS)

    Yan, Taiming; Hu, Jiaxiang; Cai, Yueping; Xiong, Sen; Yang, Shiyong; Wang, Xiongyan; He, Zhi

    2016-09-01

    Laboratory-reared Schizothorax davidi larvae and juveniles were examined to assess the formation and characteristics of David's schizothoracin otoliths. Otolith development was observed and their formation period was verified by monitoring larvae and juveniles of known age. The results revealed that lapilli and sagittae developed before hatching, and the first otolith increment was identified at 2 days post hatching in both. The shape of lapilli was relatively stable during development compared with that of sagittae; however, growth of four sagittae and lapilli areas was consistent, but the posterior area grew faster than the anterior area and the ventral surface grew faster than the dorsal surface. Similarly, the sum length of the radius of the anterior and posterior areas on sagittae and lapilli were linearly and binomially related to total fish length, respectively. Moreover, daily deposition rates were validated by monitoring known-age larvae and juveniles. The increase in lapilli width was 1.88±0.080 0 μm at the ninth increment, which reached a maximum and the decreased gradually toward the otolith edge, whereas that of sagittae increased more slowly. These results illustrate the developmental biology of S. davidi, which will aid in population conservation and fish stock management.

  14. Chemical agents and peptides affect hair growth.

    PubMed

    Uno, H; Kurata, S

    1993-07-01

    During the past decade we have examined both the therapeutic and the prophylactic effects of several agents on the macaque model of androgenetic alopecia. Minoxidil and diazoxide, potent hypotensive agents acting as peripheral vasodilators, are known to have a hypertrichotic side effect. Topical use of both agents induced significant hair regrowth in the bald scalps of macaques. The application of a steroid 5 alpha-reductase inhibitor (4MA) in non-bald preadolescent macaques has prevented baldness, whereas controls developed it during 2 years of treatment. The effects of hair growth were determined by 1) phototrichogram, 2) folliculogram (micro-morphometric analysis), and 3) the rate of DNA synthesis in the follicular cells. These effects were essentially a stimulation of the follicular cell proliferation, resulting in an enlargement of the anagen follicles from vellus to terminal type (therapy) or a maintenance of the prebald terminal follicles (prevention). A copper binding peptide (PC1031) had the effect of follicular enlargement on the back skin of fuzzy rats, covering the vellus follicles; the effect was similar to that of topical minoxidil. Analyzing the quantitative sequences of follicular size and cyclic phases, we speculate on the effect of agents on follicular growth. We also discuss the triggering mechanism of androgen in the follicular epithelial-mesenchymal (dermal papilla) interaction.

  15. CO2 induced seawater acidification impacts sea urchin larval development I: elevated metabolic rates decrease scope for growth and induce developmental delay.

    PubMed

    Stumpp, M; Wren, J; Melzner, F; Thorndyke, M C; Dupont, S T

    2011-11-01

    Anthropogenic CO(2) emissions are acidifying the world's oceans. A growing body of evidence is showing that ocean acidification impacts growth and developmental rates of marine invertebrates. Here we test the impact of elevated seawater pCO(2) (129 Pa, 1271 μatm) on early development, larval metabolic and feeding rates in a marine model organism, the sea urchin Strongylocentrotus purpuratus. Growth and development was assessed by measuring total body length, body rod length, postoral rod length and posterolateral rod length. Comparing these parameters between treatments suggests that larvae suffer from a developmental delay (by ca. 8%) rather than from the previously postulated reductions in size at comparable developmental stages. Further, we found maximum increases in respiration rates of +100% under elevated pCO(2), while body length corrected feeding rates did not differ between larvae from both treatments. Calculating scope for growth illustrates that larvae raised under high pCO(2) spent an average of 39 to 45% of the available energy for somatic growth, while control larvae could allocate between 78 and 80% of the available energy into growth processes. Our results highlight the importance of defining a standard frame of reference when comparing a given parameter between treatments, as observed differences can be easily due to comparison of different larval ages with their specific set of biological characters.

  16. Growth and Development of Larval Bay Scallops (Argopecten irradians) in Response to Early Exposure to High CO2

    DTIC Science & Technology

    2013-02-01

    S .  Peck.  2009.  Early  larval   development  of  the  Sydney...Kurihara,  H.,   S .  Kato,  and  A.  Ishimatsu.  2007.  Effects  of  increased  seawater  pCO2  on   early   development ...and  L.   S .  Peck.  2009.  Early  larval   development  of  the  Sydney  rock  oyster  Saccostrea  glomerata

  17. Expression analysis of the insulin-like growth factors I and II during embryonic and early larval development of turbot ( Scophthalmus maximus)

    NASA Astrophysics Data System (ADS)

    Wen, Haishen; Qi, Qian; Hu, Jian; Si, Yufeng; He, Feng; Li, Jifang

    2015-04-01

    The insulin-like growth factors I and II (IGF-I and IGF-II) are important proteins involved in fish growth and development. Here, we report the isolation of IGF-II and expression analysis of IGFs in turbot Scophthalmus maximus, aiming to clarify their function in embryonic and larval development of fish. The deduced IGF-II gene is 808 bp in full length, which encodes a protein of 219 amino acids and is 93% similar with that of Paralichthys olicaceus in amino acid sequence. The tissue abundance and the expression pattern of IGFs in a turbot at early development stages were investigated via reverse transcription-polymer chain reaction. Result showed that the IGF-I and IGF-II genes were widely expressed in tissues of S. maximus. IGF-I was detected in all tissues except intestines with the highest level in liver, while IGF-II transcript presented in all tissues except muscle. At the stages of embryonic and larval development, the mRNA levels of IGFs sharply increased from the stage of unfertilized egg to post larva, followed by a decrease with larval development. However, there was an increase in IGF-I at the embryonic stage and IGF-II at the gastrula stage, respectively. These results suggested that IGFs play important roles in cell growth and division of the turbot. Our study provides reference data for further investigation of growth regulation in turbot, which can guarantee better understanding of the physiological role that IGFs play in fish.

  18. GROWTH AND BEHAVIOR OF LARVAL ZEBRAFISH Danio rerio FED A PROCESSED DIET, LIVE FOOD, OR THE COMBINATION

    EPA Science Inventory

    Because Zebrafish (Danio rerio) have become a popular and important model for scientific research, the capability to rear larval zebrafish to adulthood is of great importance. Recently research examining the effects of diet (live versus processed) have been published. In the cu...

  19. TIF-IA-dependent regulation of ribosome synthesis in drosophila muscle is required to maintain systemic insulin signaling and larval growth.

    PubMed

    Ghosh, Abhishek; Rideout, Elizabeth J; Grewal, Savraj S

    2014-10-01

    The conserved TOR kinase signaling network links nutrient availability to cell, tissue and body growth in animals. One important growth-regulatory target of TOR signaling is ribosome biogenesis. Studies in yeast and mammalian cell culture have described how TOR controls rRNA synthesis-a limiting step in ribosome biogenesis-via the RNA Polymerase I transcription factor TIF-IA. However, the contribution of TOR-dependent ribosome synthesis to tissue and body growth in animals is less clear. Here we show in Drosophila larvae that ribosome synthesis in muscle is required non-autonomously to maintain normal body growth and development. We find that amino acid starvation and TOR inhibition lead to reduced levels of TIF-IA, and decreased rRNA synthesis in larval muscle. When we mimic this decrease in muscle ribosome synthesis using RNAi-mediated knockdown of TIF-IA, we observe delayed larval development and reduced body growth. This reduction in growth is caused by lowered systemic insulin signaling via two endocrine responses: reduced expression of Drosophila insulin-like peptides (dILPs) from the brain and increased expression of Imp-L2-a secreted factor that binds and inhibits dILP activity-from muscle. We also observed that maintaining TIF-IA levels in muscle could partially reverse the starvation-mediated suppression of systemic insulin signaling. Finally, we show that activation of TOR specifically in muscle can increase overall body size and this effect requires TIF-IA function. These data suggest that muscle ribosome synthesis functions as a nutrient-dependent checkpoint for overall body growth: in nutrient rich conditions, TOR is required to maintain levels of TIF-IA and ribosome synthesis to promote high levels of systemic insulin, but under conditions of starvation stress, reduced muscle ribosome synthesis triggers an endocrine response that limits systemic insulin signaling to restrict growth and maintain homeostasis.

  20. TIF-IA-Dependent Regulation of Ribosome Synthesis in Drosophila Muscle Is Required to Maintain Systemic Insulin Signaling and Larval Growth

    PubMed Central

    Ghosh, Abhishek; Rideout, Elizabeth J.; Grewal, Savraj S.

    2014-01-01

    The conserved TOR kinase signaling network links nutrient availability to cell, tissue and body growth in animals. One important growth-regulatory target of TOR signaling is ribosome biogenesis. Studies in yeast and mammalian cell culture have described how TOR controls rRNA synthesis—a limiting step in ribosome biogenesis—via the RNA Polymerase I transcription factor TIF-IA. However, the contribution of TOR-dependent ribosome synthesis to tissue and body growth in animals is less clear. Here we show in Drosophila larvae that ribosome synthesis in muscle is required non-autonomously to maintain normal body growth and development. We find that amino acid starvation and TOR inhibition lead to reduced levels of TIF-IA, and decreased rRNA synthesis in larval muscle. When we mimic this decrease in muscle ribosome synthesis using RNAi-mediated knockdown of TIF-IA, we observe delayed larval development and reduced body growth. This reduction in growth is caused by lowered systemic insulin signaling via two endocrine responses: reduced expression of Drosophila insulin-like peptides (dILPs) from the brain and increased expression of Imp-L2—a secreted factor that binds and inhibits dILP activity—from muscle. We also observed that maintaining TIF-IA levels in muscle could partially reverse the starvation-mediated suppression of systemic insulin signaling. Finally, we show that activation of TOR specifically in muscle can increase overall body size and this effect requires TIF-IA function. These data suggest that muscle ribosome synthesis functions as a nutrient-dependent checkpoint for overall body growth: in nutrient rich conditions, TOR is required to maintain levels of TIF-IA and ribosome synthesis to promote high levels of systemic insulin, but under conditions of starvation stress, reduced muscle ribosome synthesis triggers an endocrine response that limits systemic insulin signaling to restrict growth and maintain homeostasis. PMID:25356674

  1. Effect of Larval Density on Food Utilization Efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae).

    PubMed

    Morales-Ramos, Juan A; Rojas, M Guadalupe

    2015-10-01

    Crowding conditions of larvae may have a significant impact on commercial production efficiency of some insects, such as Tenebrio molitor L. (Coleoptera: Tenebrionidae). Although larval densities are known to affect developmental time and growth in T. molitor, no reports were found on the effects of crowding on food utilization. The effect of larval density on food utilization efficiency of T. molitor larvae was studied by measuring efficiency of ingested food conversion (ECI), efficiency of digested food conversion (EDC), and mg of larval weight gain per gram of food consumed (LWGpFC) at increasing larval densities (12, 24, 36, 48, 50, 62, 74, and 96 larvae per dm(2)) over four consecutive 3-wk periods. Individual larval weight gain and food consumption were negatively impacted by larval density. Similarly, ECI, ECD, and LWGpFC were negatively impacted by larval density. Larval ageing, measured as four consecutive 3-wk periods, significantly and independently impacted ECI, ECD, and LWGpFC in a negative way. General linear model analysis showed that age had a higher impact than density on food utilization parameters of T. molitor larvae. Larval growth was determined to be responsible for the age effects, as measurements of larval mass density (in grams of larvae per dm(2)) had a significant impact on food utilization parameters across ages and density treatments (in number of larvae per dm(2)). The importance of mass versus numbers per unit of area as measurements of larval density and the implications of negative effects of density on food utilization for insect biomass production are discussed.

  2. Larval gizzard shad characteristics in Lake Oahe, South Dakota: A species at the northern edge of its range

    USGS Publications Warehouse

    Fincel, Mark J.; Chipps, Steven R.; Graeb, Brian D. S.; Edwards, Kris R.

    2013-01-01

    Gizzard shad, Dorosoma cepedianum, have generally been restricted to the lower Missouri River impoundments in South Dakota. In recent years, gizzard shad numbers have increased in Lake Oahe, marking the northern-most natural population. These increases could potentially affect recreational fishes. Specifically, questions arise about larval gizzard shad growth dynamics and if age-0 gizzard shad in Lake Oahe will exhibit fast or slow growth, both of which can have profound effects on piscivore populations in this reservoir. In this study, we evaluated larval gizzard shad hatch timing, growth, and density in Lake Oahe. We collected larval gizzard shad from six sites from May to July 2008 and used sagittal otoliths to estimate the growth and back-calculate the hatch date. We found that larval gizzard shad hatched earlier in the upper part of the reservoir compared to the lower portion and that hatch date appeared to correspond to warming water temperatures. The peak larval gizzard shad density ranged from 0.6 to 33.6 (#/100 m3) and varied significantly among reservoir sites. Larval gizzard shad growth ranged from 0.24 to 0.57 (mm/d) and differed spatially within the reservoir. We found no relationship between the larval gizzard shad growth or density and small- or large-bodied zooplankton density (p > 0.05). As this population exhibits slow growth and low densities, gizzard shad should remain a suitable forage option for recreational fishes in Lake Oahe.

  3. EGF-mediated EGFR/ERK signaling pathway promotes germinative cell proliferation in Echinococcus multilocularis that contributes to larval growth and development

    PubMed Central

    Li, Xiu; Dai, Mengya; Wu, Jianjian; Guo, Xinrui; Tian, Huimin; Heng, Zhijie; Lu, Ying; Chai, Xiaoli

    2017-01-01

    Background Larvae of the tapeworm E. multilocularis cause alveolar echinococcosis (AE), one of the most lethal helminthic infections in humans. A population of stem cell-like cells, the germinative cells, is considered to drive the larval growth and development within the host. The molecular mechanisms controlling the behavior of germinative cells are largely unknown. Methodology/Principal findings Using in vitro cultivation systems we show here that the EGFR/ERK signaling in the parasite can promote germinative cell proliferation in response to addition of human EGF, resulting in stimulated growth and development of the metacestode larvae. Inhibition of the signaling by either the EGFR inhibitors CI-1033 and BIBW2992 or the MEK/ERK inhibitor U0126 impairs germinative cell proliferation and larval growth. Conclusions/Significance These data demonstrate the contribution of EGF-mediated EGFR/ERK signaling to the regulation of germinative cells in E. multilocularis, and suggest the EGFR/ERK signaling as a potential therapeutic target for AE and perhaps other human cestodiasis. PMID:28241017

  4. Nitrogen fertilization rate affects feeding, larval performance, and oviposition preference of the beet armyworm, Spodoptera exigua, on cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) is one of the most critical chemical elements for plant and animal growth. Development and oviposition of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) was studied in relation to varying nitrogen levels in cotton, Gossypium hirsutum L. The development of S. exig...

  5. Modeling larval connectivity of the Atlantic surfclams within the Middle Atlantic Bight: Model development, larval dispersal and metapopulation connectivity

    NASA Astrophysics Data System (ADS)

    Zhang, Xinzhong; Haidvogel, Dale; Munroe, Daphne; Powell, Eric N.; Klinck, John; Mann, Roger; Castruccio, Frederic S.

    2015-02-01

    To study the primary larval transport pathways and inter-population connectivity patterns of the Atlantic surfclam, Spisula solidissima, a coupled modeling system combining a physical circulation model of the Middle Atlantic Bight (MAB), Georges Bank (GBK) and the Gulf of Maine (GoM), and an individual-based surfclam larval model was implemented, validated and applied. Model validation shows that the model can reproduce the observed physical circulation patterns and surface and bottom water temperature, and recreates the observed distributions of surfclam larvae during upwelling and downwelling events. The model results show a typical along-shore connectivity pattern from the northeast to the southwest among the surfclam populations distributed from Georges Bank west and south along the MAB shelf. Continuous surfclam larval input into regions off Delmarva (DMV) and New Jersey (NJ) suggests that insufficient larval supply is unlikely to be the factor causing the failure of the population to recover after the observed decline of the surfclam populations in DMV and NJ from 1997 to 2005. The GBK surfclam population is relatively more isolated than populations to the west and south in the MAB; model results suggest substantial inter-population connectivity from southern New England to the Delmarva region. Simulated surfclam larvae generally drift for over one hundred kilometers along the shelf, but the distance traveled is highly variable in space and over time. Surfclam larval growth and transport are strongly impacted by the physical environment. This suggests the need to further examine how the interaction between environment, behavior, and physiology affects inter-population connectivity. Larval vertical swimming and sinking behaviors have a significant net effect of increasing larval drifting distances when compared with a purely passive model, confirming the need to include larval behavior.

  6. Drosophila adult and larval pheromones modulate larval food choice

    PubMed Central

    Farine, Jean-Pierre; Cortot, Jérôme; Ferveur, Jean-François

    2014-01-01

    Insects use chemosensory cues to feed and mate. In Drosophila, the effect of pheromones has been extensively investigated in adults, but rarely in larvae. The colonization of natural food sources by Drosophila buzzatii and Drosophila simulans species may depend on species-specific chemical cues left in the food by larvae and adults. We identified such chemicals in both species and measured their influence on larval food preference and puparation behaviour. We also tested compounds that varied between these species: (i) two larval volatile compounds: hydroxy-3-butanone-2 and phenol (predominant in D. simulans and D. buzzatii, respectively), and (ii) adult cuticular hydrocarbons (CHs). Drosophila buzzatii larvae were rapidly attracted to non-CH adult conspecific cues, whereas D. simulans larvae were strongly repulsed by CHs of the two species and also by phenol. Larval cues from both species generally reduced larval attraction and pupariation on food, which was generally—but not always—low, and rarely reflected larval response. As these larval and adult pheromones specifically influence larval food search and the choice of a pupariation site, they may greatly affect the dispersion and survival of Drosophila species in nature. PMID:24741012

  7. Expression of the maize proteinase inhibitor (mpi) gene in rice plants enhances resistance against the striped stem borer (Chilo suppressalis): effects on larval growth and insect gut proteinases.

    PubMed

    Vila, Laura; Quilis, Jordi; Meynard, Donaldo; Breitler, Jean Christophe; Marfà, Victoria; Murillo, Isabel; Vassal, Jean Michel; Messeguer, Joaquima; Guiderdoni, Emmanuel; San Segundo, Blanca

    2005-03-01

    The maize proteinase inhibitor (mpi) gene was introduced into two elite japonica rice varieties. Both constitutive expression of the mpi gene driven by the maize ubiquitin 1 promoter and wound-inducible expression of the mpi gene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants. No effect on plant phenotype was observed in mpi-expressing lines. The stability of transgene expression through successive generations of mpi rice lines (up to the T(4) generation) and the production of functional MPI protein were confirmed. Expression of the mpi gene in rice enhanced resistance to the striped stem borer (Chilo suppressalis), one of the most important pests of rice. In addition, transgenic mpi plants were evaluated in terms of their effects on the growth of C. suppressalis larvae and the insect digestive proteolytic system. An important dose-dependent reduction of larval weight of C. suppressalis larvae fed on mpi rice, compared with larvae fed on untransformed rice plants, was observed. Analysis of the digestive proteolytic activity from the gut of C. suppressalis demonstrated that larvae adapted to mpi transgene expression by increasing the complement of digestive proteolytic activity: the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B. However, the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth. The introduction of the mpi gene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer.

  8. Variation in food availability mediate the impact of density on cannibalism, growth, and survival in larval yellow spotted mountain newts (Neurergus microspilotus): Implications for captive breeding programs.

    PubMed

    Vaissi, Somaye; Sharifi, Mozafar

    2016-11-01

    In this study, we examined cannibalistic behavior, growth, metamorphosis, and survival in larval and post-metamorph endangered yellow spotted mountain newts Neurergus microspilotus hatched and reared in a captive breeding facility. We designed a 2 × 2 factorial experiment, crossing two levels of food with two levels of density including high food/high density, high food/low density, low food/high density, and low food/low density. The level of cannibalistic behavior (including the loss of fore and hind limbs, missing toes, tail, gills, body damage, and whole body consumption) changed as the larvae grew, from a low level during the first 4 weeks, peaking from weeks 7 to 12, and then dropped during weeks 14-52. Both food level and density had a significant effect on cannibalism. The highest frequency of cannibalism was recorded for larvae reared in the low food/high density and lowest in high food/low density treatments. Growth, percent of larval metamorphosed, and survival were all highest in the high food/low density and lowest in low food/high density treatment. Food level had a significant effect on growth, metamorphosis, and survival. However, the two levels of density did not influence growth and metamorphosis but showed a significant effect on survival. Similarly, combined effects of food level and density showed significant effects on growth, metamorphosis, and survival over time. Information obtained from current experiment could improve productivity of captive breeding facilities to ensure the release of adequate numbers of individuals for reintroduction programs. Zoo Biol. 35:513-521, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

  9. Development of the larval amphibian growth and development assay: Effects of chronic 4-tert-octylphenol or 17ß-trenbolone exposure in Xenopus laevis from embryo to juvenile

    EPA Science Inventory

    The Larval Amphibian Growth and Development Assay (LAGDA) is a Tier II test guideline being developed by the US Environmental Protection Agency under the Endocrine Disruptor Screening Program. The LAGDA was designed to evaluate effects of chronic chemical exposure on growth, thy...

  10. Effects of intraspecific larval competition on adult longevity in the mosquitoes Aedes aegypti and Aedes albopictus

    PubMed Central

    LOUNIBOS, L. P.

    2009-01-01

    Larval competition is common in container-breeding mosquitoes. The impact of competition on larval growth has been thoroughly examined and findings that larval competition can lead to density-dependent effects on adult body size have been documented. The effects of larval competition on adult longevity have been less well explored. The effects of intraspecific larval densities on the longevity of adults maintained under relatively harsh environmental conditions were tested in the laboratory by measuring the longevity of adult Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae) that had been reared under a range of larval densities and subsequently maintained in high- or low-humidity regimes (85% or 35% relative humidity [RH], respectively) as adults. We found significant negative effects of competition on adult longevity in Ae. aegypti, but not in Ae. albopictus. Multivariate analysis of variance suggested that the negative effect of the larval environment on the longevity of Ae. aegypti adults was most strongly associated with increased development time and decreased wing length as adults. Understanding how larval competition affects adult longevity under a range of environmental conditions is important in establishing the relationship between models of mosquito population regulation and epidemiological models of vector-borne disease transmission. PMID:19239615

  11. Effect of n-3 HUFA levels in rotifers and Artemia on growth and survival of larval black sea bream ( Sparus macrocephalus)

    NASA Astrophysics Data System (ADS)

    Liu, Jingke; Li, Kuiran; Huang, Bingxin; Chen, Xiaolin

    2004-12-01

    Requirement for dietary n-3 HUFA (n-3 highly unsaturated fatty acid) for growth and survival of black sea bream ( Sparus macrocephalus) larvae was studied using rotifers and Artemia at various levels of n-3 HUFA. Five treatments with rotifers and Artemia differing in n-3 HUFA were prepared by enriching them with various oil emulsions. Results indicated that dietary n-3 HUFA significantly influence fish n-3 HUFA levels and are essential for growth and survival of black sea bream larvae. The results also indicated that the incorporation of n-3HUFA TG (triacylglycerols) into tissues of larval black sea bream was more effective from natural fish oil in comparison with n-3 HUFA fatty acid ethyl esters from ethyl-esterified oil.

  12. Growth and ontogeny of the tapeworm Schistocephalus solidus in its copepod first host affects performance in its stickleback second intermediate host

    PubMed Central

    2012-01-01

    Background For parasites with complex life cycles, size at transmission can impact performance in the next host, thereby coupling parasite phenotypes in the two consecutive hosts. However, a handful of studies with parasites, and numerous studies with free-living, complex-life-cycle animals, have found that larval size correlates poorly with fitness under particular conditions, implying that other traits, such as physiological or ontogenetic variation, may predict fitness more reliably. Using the tapeworm Schistocephalus solidus, we evaluated how parasite size, age, and ontogeny in the copepod first host interact to determine performance in the stickleback second host. Methods We raised infected copepods under two feeding treatments (to manipulate parasite growth), and then exposed fish to worms of two different ages (to manipulate parasite ontogeny). We assessed how growth and ontogeny in copepods affected three measures of fitness in fish: infection probability, growth rate, and energy storage. Results Our main, novel finding is that the increase in fitness (infection probability and growth in fish) with larval size and age observed in previous studies on S. solidus seems to be largely mediated by ontogenetic variation. Worms that developed rapidly (had a cercomer after 9 days in copepods) were able to infect fish at an earlier age, and they grew to larger sizes with larger energy reserves in fish. Infection probability in fish increased with larval size chiefly in young worms, when size and ontogeny are positively correlated, but not in older worms that had essentially completed their larval development in copepods. Conclusions Transmission to sticklebacks as a small, not-yet-fully developed larva has clear costs for S. solidus, but it remains unclear what prevents the evolution of faster growth and development in this species. PMID:22564512

  13. Feeding and larval growth of an exotic freshwater prawn Macrobrachium equidens (Decapoda: Palaemonidae), from Northeastern Pará, Amazon Region.

    PubMed

    Gomes, Jean N; Abrunhosa, Fernando A; Costa, Anne K; Maciel, Cristiana R

    2014-09-01

    In the present study, we carried out experiments on the diet of the freshwater prawn Macrobrachium equidens. We tested which type of food and which density of food is suitable for larval development. For the experiment on the type of food, eight treatments were carried out: (I) starvation, (AL) microalgae, (RO) rotifers, (AN) Artemia, (RO + AN) rotifers + Artemia, (AL + RO) microalgae + rotifers, (AL + AN) microalgae + Artemia, (AL + RO + AN) microalgae + rotifers + Artemia. For the experiment on the density of food, we used the type of food, which had resulted in a high survival rate in the previous experiment. Three treatments were carried out: 4, 8 and 16 Artemia nauplii /mL. The rate of feeding during larval development was observed. The survival, weight and percentage of juveniles of each feeding experiment were determined. We found that larvae are carnivores; however, they have requirements with respect to the type of food, because larvae completed their cycle from the zoeal to the juvenile stage only when Artemia nauplii were available. We also verified that the larvae feed mainly during the day-time, and are opportunistic with respect to the density of food offered.

  14. Interactions of gonadal steroids and pesticides (DDT, DDE) on gonaduct growth in larval tiger salamanders, Ambystoma tigrinum.

    PubMed

    Clark, E J; Norris, D O; Jones, R E

    1998-01-01

    In view of the current worldwide decline in amphibian populations, exploratory studies are needed to assess the potential for environmental contaminants to act as endocrine disrupters of the amphibian reproductive system. The present study investigated the effects of DDT dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) on the development of amphibian gonaducts. Larval male and female tiger salamanders (Ambystoma tigrinum), with immature gonads, were immersed in a sublethal solution of p,p'-DDE or technical-grade DDT (80% p,p'-DDT and 20% o,p'-DDT). Additionally, larvae were injected with the steroid hormones estradiol or dihydrotestosterone (DHT). Morphometrics were used to analyze the effects and interactions of steroid and pesticide treatments on larval gonaducts. Estradiol and DHT stimulated cell proliferation and hypertrophy of the müllerian duct epithelium in both sexes. Wolffian duct epithelium, however, was stimulated only by DHT treatment. The pesticide DDT antagonized the estrogenic actions of the steroid treatments, and p,p'-DDE acted as an estrogen on the müllerian ducts of females only. The müllerian ducts of males, and the wolffian ducts of both sexes, were unaffected by DDT or DDE alone. While confirming the previously reported estrogenic actions of estradiol and DHT on urodelean gonaducts, the results contradict the expected estrogenic actions of DDT and antiandrogenic actions of p,p'-DDE. Instead, in A. tigrinum, technical-grade DDT had an antiestrogenic action and p,p'-DDE an estrogenic action.

  15. Using the Larval Zebrafish Locomotor Asssay in Functional Neurotoxicity Screening: Light Brightness and the Order of Stimulus Presentation Affect the Outcome

    EPA Science Inventory

    We are evaluating methods to screen/prioritize large numbers of chemicals using 6 day old zebrafish (Danio rerio) as an alternative model for detecting neurotoxic effects. Our behavioral testing paradigm simultaneously tests individual larval zebrafish under sequential light and...

  16. Muscle development and body growth in larvae and early post-larvae of shi drum, Umbrina cirrosa L., reared under different larval photoperiod: muscle structural and ultrastructural study.

    PubMed

    Ayala, Maria D; Abellán, Emilia; Arizcun, Marta; García-Alcázar, Alicia; Navarro, F; Blanco, Alfonso; López-Albors, Octavio M

    2013-08-01

    Shi drum specimens were maintained under four different photoperiod regimes: a natural photoperiod regime (16L:8D), constant light (24L), equal durations of light and dark (12L:12D) and a reduced number of daylight hours (6L:18D) from hatching until the end of larval metamorphosis. Specimens were then kept under natural photoperiod conditions until 111 days post-hatching. Muscle and body parameters were studied. During the vitelline phase, there was little muscle growth and no photoperiod effects were reported; however, a monolayer of red muscle and immature white muscle fibres were observed in the myotome. At hatching, external cells (presumptive myogenic cells) were already present on the surface of the red muscle. At the mouth opening, some presumptive myogenic cells appeared between the red and white muscles. At 20 days, new germinal areas were observed in the apical extremes of the myotome. At this stage, the 16L:8D group (followed by the 24L group) had the longest body length, the largest cross-sectional area of white muscle and the largest white muscle fibres. Conversely, white muscle hyperplasia was most pronounced in the 24L group. Metamorphosis was complete at 33 days in the 24L and 12L:12D groups. At this moment, both groups showed numerous myogenic precursors on the surface of the myotome as well as among the adult muscle fibres (mosaic hyperplastic growth). The 16L:8D group completed metamorphosis at 50 days, showing a similar degree of structural maturity in the myotome to that described in the 24L and 12L:12D groups at 33 days. When comparing muscle growth at the end of the larval period, hypertrophy was highest in the 16L:8D group, whereas hyperplasia was higher in the 24L and 16L:8D groups. At 111 days, all groups showed the adult muscle pattern typical of teleosts; however, the cross-sectional area of white muscle, white muscle fibre hyperplasia, body length and body weight were highest in the 24L group, followed by the 12L:12D group; white muscle

  17. Artificial miRNA-mediated silencing of ecdysone receptor (EcR) affects larval development and oogenesis in Helicoverpa armigera.

    PubMed

    Yogindran, Sneha; Rajam, Manchikatla Venkat

    2016-10-01

    The insect pests are real threat to farmers as they affect the crop yield to a great extent. The use of chemical pesticides for insect pest control has always been a matter of concern as they pollute the environment and are also harmful for human health. Bt (Bacillus thuringensis) technology helped the farmers to get rid of the insect pests, but experienced a major drawback due to the evolution of insects gaining resistance towards these toxins. Hence, alternative strategies are high on demand to control insect pests. RNA-based gene silencing is emerging as a potential tool to tackle with this problem. In this study, we have shown the use of artificial microRNA (amiRNA) to specifically target the ecdysone receptor (EcR) gene of Helicoverpa armigera (cotton bollworm), which attacks several important crops like cotton, tomato chickpea, pigeon pea, etc and causes huge yield losses. Insect let-7a precursor miRNA (pre-miRNA) backbone was used to replace the native miRNA with that of amiRNA. The precursor backbone carrying the 21 nucleotide amiRNA sequence targeting HaEcR was cloned in bacterial L4440 vector for in vitro insect feeding experiments. Larvae fed with Escherichia coli expressing amiRNA-HaEcR showed a reduction in the expression of target gene as well as genes involved in the ecdysone signaling pathway downstream to EcR and exhibited mortality and developmental defects. Stem-loop RT-PCR revealed the presence of amiRNA in the insect larvae after feeding bacteria expressing amiRNA-HaEcR, which was otherwise absent in controls. We also found a significant drop in the reproduction potential (oogenesis) of moths which emerged from treated larvae as compared to control. These results demonstrate the successful use of an insect pre-miRNA backbone to express amiRNA for gene silencing studies in insects. The method is cost effective and can be exploited as an efficient and alternative tool for insect pest management.

  18. Spaceflight and age affect tibial epiphyseal growth plate histomorphometry

    NASA Technical Reports Server (NTRS)

    Montufar-Solis, Dina; Duke, Pauline J.; Durnova, G.

    1992-01-01

    Growth plate histomorphometry of rats flown aboard the Soviet biosatellite Cosmos 2044, a 14-day spaceflight, was compared with that of control groups. In growth plates of flight animals, there was a significant increase in cell number per column and height of the proliferative zone and a reduction in height and cell number in the hypertrophy/calcification zone. No significant differences were found in matrix organization at the ultrastructural level of flight animals, indicating that although spacefligfht continues to affect bone growth of 15-wk-old rats, extracellular matrix is not altered in the same manner as seen previously in younger animals. All groups showed growth plate characteristics attributed to aging: lack of calcification zone, reduced hypertrophy zone, and unraveling of collagen fibrils. Tail-suspended controls did not differ from other controls in any of the parameters measured. The results suggest that growth plates of older rats are less responsive to unloading by spaceflight or suspension than those of younger rats and provide new evidence about the modifying effect of spaceflight on the growth plate.

  19. Preliminary terrestrial based experiments on gravity-affected crystal growth

    NASA Technical Reports Server (NTRS)

    Johnston, M. H.

    1970-01-01

    Tin was melted in a heating assembly secured to the arm of a centrifuge. The furnace was allowed to pivot and reach its equilibrium angle of swing for the gravity force being experienced. The crucible was cooled during rotation to allow the growth of single crystals. The crystals were etched for the purpose of observing the growth striations. Slices were removed from some of the crystals to permit observation of the striations in the interior. Visual analyses were made with a scanning electron microscope. Preliminary conclusions relating the appearance of the striations to gravity forces and the affected growth mechanisms are presented. Further experiments that will verify these conclusions and determine other gravity effects are proposed.

  20. Factors affecting growth of foodborne pathogens on minimally processed apples.

    PubMed

    Alegre, Isabel; Abadias, Maribel; Anguera, Marina; Oliveira, Marcia; Viñas, Inmaculada

    2010-02-01

    Escherichia coli O157:H7, Salmonella and Listeria innocua increased by more than 2 log(10) units over a 24 h period on fresh-cut 'Golden Delicious' apple plugs stored at 25 and 20 degrees C. L. innocua reached the same final population level at 10 degrees C meanwhile E. coli and Salmonella only increased 1.3 log(10) units after 6 days. Only L. innocua was able to grow at 5 degrees C. No significant differences were observed between the growth of foodborne pathogens on fresh-cut 'Golden Delicious', 'Granny Smith' and 'Shampion' apples stored at 25 and 5 degrees C. The treatment of 'Golden Delicious' and 'Granny Smith' apple plugs with the antioxidants, ascorbic acid (2%) and NatureSeal (6%), did not affect pathogen growth. The effect of passive modified atmosphere packaging (MAP) on the growth of E. coli, Salmonella and L. innocua on 'Golden Delicious' apple slices was also tested. There were no significant differences in growth of pathogens in MAP conditions compared with air packaging of 'Golden Delicious' apple plugs, but the growth of mesophilic and psychrotrophic microorganisms was inhibited. These results highlight the importance of avoiding contamination of fresh-cut fruit with foodborne pathogens and the maintenance of the cold chain during storage until consumption.

  1. The effects of elutriates from PAH and heavy metal polluted sediments on Crassostrea gigas (Thunberg) embryogenesis, larval growth and bio-accumulation by the larvae of pollutants from sedimentary origin.

    PubMed

    Geffard, Olivier; Budzinski, Hélène; His, Edouard

    2002-12-01

    The release, bio-availability and toxicity of contaminants, when sediments are resuspended have been examined, studying concurrently their effects on the embryogenesis and on the larval growth of the Crassostrea gigas larvae and their bio-accumulation in those organisms. Three characteristic sediments have been selected (one contaminated by PAHs, a second by heavy metals and the last by the both pollutants). The organisms were directly exposed to elutriates obtained from each sediment or fed on algae (Isochrysis galbana) contaminated with the same elutriates. The elutriates used in this study show contamination levels similar to those observed in some polluted coastal and estuary environments. The larval growth test has appeared to be more sensitive that the embryotoxicity test. The biological effects and the contaminant bio-accumulation were more pronounced when larvae were directly exposed to different elutriates. In the case of PAHs, the contamination of algae was sufficient to lead to effect on the larval growth of the Crassostrea gigas. In all cases, a fraction of contaminants adsorbed on suspended particles was bio-available and accumulated by the larvae. This study has shown that resuspending polluted sediments constitutes a threat to pelagic organisms and than the C. gigas larval growth may be proposed as a test to protect the most sensitive areas.

  2. Effects of larval density in Ambystoma opacum: An experiment in large-scale field enclosures

    SciTech Connect

    Scott, D.E. )

    1990-02-01

    This experiment was designed to measure the effects of larval density on larval traits in the salamander Ambystoma opacum, and to ascertain whether previous studies conducted at smaller spatial scales or higher densities produced artifactual results. Density effects on larval growth, body size at metamorphosis, length of larval period, and survival to metamorphosis were studied in A. opacum in large-scale (41 m{sup 2} and 23 m{sup 2}) field enclosures in two temporary ponds. Each enclosure contained indigenous populations of prey (zooplankton and insects) and predators, as well as the range of microhabitats present in these natural ponds. Initial larval densities were chosen to represent high and low levels of naturally occurring mean densities. The results suggest that, in natural ponds, the importance of intraspecific competition is dependent upon hydroperiod, and the intensity of competition influences predation risk. Thus, both density-dependent and density-independent factors affect body size and recruitment of larval A. opacum into the adult population. The use of large-scale field enclosures has advantages and disadvantages: it allows the examination of density-dependent processes under natural conditions and provides high statistical power because of low variability in larval traits; however, experimental designs must be simple and underlying mechanisms are difficult to identify.

  3. Eukaryotic translation initiation factor 5B activity regulates larval growth rate and germline development in Caenorhabditis elegans.

    PubMed

    Yu, Xiang; Vought, Valarie E; Conradt, Barbara; Maine, Eleanor M

    2006-09-01

    In C. elegans, a population of proliferating germ cells is maintained via GLP-1/Notch signaling; in the absence of GLP-1 signaling, germ cells prematurely enter meiosis and differentiate. We previously identified ego (enhancer of glp-1) genes that promote germline proliferation and interact genetically with the GLP-1 signaling pathway. Here, we report that iffb-1 (initiation factor five B) is an ego gene. iffb-1 encodes the sole C. elegans isoform of eukaryotic translation initiation factor 5B, a protein essential for translation. We have used RNA interference and a deletion mutation to determine the developmental consequences of reduced iffb-1 activity. Our data indicate that maternal iffb-1 gene expression is sufficient for embryogenesis, and zygotic iffb-1 expression is required for development beyond late L1/early L2 stage. Partial reduction in iffb-1 expression delays larval development and can severely disrupt proliferation and differentiation of germ cells. We hypothesize that germline development is particularly sensitive to iffb-1 expression level.

  4. Development of the Larval Amphibian Growth and Development Assay: Effects of benzophenone-2 exposure in Xenopus laevis from embryo to juvenile.

    PubMed

    Haselman, Jonathan T; Sakurai, Maki; Watanabe, Naoko; Goto, Yasushi; Onishi, Yuta; Ito, Yuki; Onoda, Yu; Kosian, Patricia A; Korte, Joseph J; Johnson, Rodney D; Iguchi, Taisen; Degitz, Sigmund J

    2016-12-01

    The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized chemical testing guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of Environment to support risk assessment. The assay is employed as a higher tiered approach to evaluate effects of chronic chemical exposure throughout multiple life stages in a model amphibian species, Xenopus laevis. To evaluate the utility of the initial LAGDA design, the assay was performed using a mixed mode of action endocrine disrupting chemical, benzophenone-2 (BP-2). X. laevis embryos were exposed in flow-through conditions to 0, 1.5, 3.0 or 6.0 mg l(-1) BP-2 until 2 months post-metamorphosis. Overt toxicity was evident throughout the exposure period in the 6.0 mg l(-1) treatment due to elevated mortality rates and observed liver and kidney pathologies. Concentration-dependent increases in severity of thyroid follicular cell hypertrophy and hyperplasia occurred in larval tadpoles indicating BP-2-induced impacts on the thyroid axis. Additionally, gonads were impacted in all treatments with some genetic males showing both testis and ovary tissues (1.5 mg l(-1) ) and 100% of the genetic males in the 3.0 and 6.0 mg l(-1) treatments experiencing complete male-to-female sex reversal. Concentration-dependent vitellogenin induction occurred in both genders with associated accumulations of protein in the livers, kidneys and gonads, which was likely vitellogenin and other estrogen-responsive yolk proteins. This is the first study that demonstrates the endocrine effects of this mixed mode of action chemical in an amphibian species and demonstrates the utility of the LAGDA design for supporting chemical risk assessment. Copyright © 2016 John Wiley & Sons, Ltd.

  5. How managed care growth affects where physicians locate their practices.

    PubMed

    Polsky, D; Escarce, J J

    2000-11-01

    Managed care has had a profound effect on physician practice. It has altered patterns in the use of physician services, and consequently, the practice and employment options available to physicians. But managed care growth has not been uniform across the United States, and has spawned wide geographic disparities in earning opportunities for generalists and specialists. This Issue Brief summarizes new information on how managed care has affected physicians' labor market decisions and the impact of managed care on the number and distribution of physicians across the country.

  6. Temperature- and sex-related effects of serine protease alleles on larval development in the Glanville fritillary butterfly.

    PubMed

    Ahola, V; Koskinen, P; Wong, S C; Kvist, J; Paulin, L; Auvinen, P; Saastamoinen, M; Frilander, M J; Lehtonen, R; Hanski, I

    2015-12-01

    The body reserves of adult Lepidoptera are accumulated during larval development. In the Glanville fritillary butterfly, larger body size increases female fecundity, but in males fast larval development and early eclosion, rather than large body size, increase mating success and hence fitness. Larval growth rate is highly heritable, but genetic variation associated with larval development is largely unknown. By comparing the Glanville fritillary population living in the Åland Islands in northern Europe with a population in Nantaizi in China, within the source of the post-glacial range expansion, we identified candidate genes with reduced variation in Åland, potentially affected by selection under cooler climatic conditions than in Nantaizi. We conducted an association study of larval growth traits by genotyping the extremes of phenotypic trait distributions for 23 SNPs in 10 genes. Three genes in clip-domain serine protease family were associated with larval growth rate, development time and pupal weight. Additive effects of two SNPs in the prophenoloxidase-activating proteinase-3 (ProPO3) gene, related to melanization, showed elevated growth rate in high temperature but reduced growth rate in moderate temperature. The allelic effects of the vitellin-degrading protease precursor gene on development time were opposite in the two sexes, one genotype being associated with long development time and heavy larvae in females but short development time in males. Sexually antagonistic selection is here evident in spite of sexual size dimorphism.

  7. Effect of larval density on food utilization efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rearing conditions, particularly the crowding of larvae, may have a significant impact on production efficiency of some insects produced commercially, such as Tenebrio molitor L. (Coleoptera: Tenebrionidae). Although larval densities are known to affect developmental time and growth in T. molitor, n...

  8. Growth, nitrogen uptake and flow in maize plants affected by root growth restriction.

    PubMed

    Xu, Liangzheng; Niu, Junfang; Li, Chunjian; Zhang, Fusuo

    2009-07-01

    The objective of the present study was to investigate the influence of a reduced maize root-system size on root growth and nitrogen (N) uptake and flow within plants. Restriction of shoot-borne root growth caused a strong decrease in the absorption of root: shoot dry weight ratio and a reduction in shoot growth. On the other hand, compensatory growth and an increased N uptake rate in the remaining roots were observed. Despite the limited long-distance transport pathway in the mesocotyl with restriction of shoot-borne root growth, N cycling within these plants was higher than those in control plants, implying that xylem and phloem flow velocities via the mesocotyl were considerably higher than in plants with an intact root system. The removal of the seminal roots in addition to restricting shoot-borne root development did not affect whole plant growth and N uptake, except for the stronger compensatory growth of the primary roots. Our results suggest that an adequate N supply to maize plant is maintained by compensatory growth of the remaining roots, increased N uptake rate and flow velocities within the xylem and phloem via the mesocotyl, and reduction in the shoot growth rate.

  9. Developmental inflexibility of larval tapeworms in response to resource variation.

    PubMed

    Benesh, Daniel P

    2010-03-15

    The timing of habitat switching in organisms with complex life cycles is an important life history characteristic that is often influenced by the larval growth environment. Under starvation, longer developmental times are frequently observed, probably as a consequence of developmental thresholds, but prolonged ontogeny sometimes also occurs under good conditions, as organisms may take advantage of the large potential gains in body size. I investigated whether variation in growth conditions affects the larval development time of a complex life cycle tapeworm (Schistocephalus solidus) in its copepod first host. Moreover, I reviewed patterns of developmental plasticity in larval tapeworms to assess the generality of my findings. Copepod starvation weakly retarded parasite growth but did not affect development. Worms grew bigger in larger copepods, but they developed at a similar rate in large and small hosts. Thus, S. solidus does not delay ontogeny under good conditions nor does it fail to reach a developmental threshold under poor conditions. Although unusual in comparison to free-living organisms, such inflexibility is common in tapeworms. Plasticity, namely prolonged ontogeny, has been mainly observed at high infection intensities. For S. solidus, there were large cross-environment genetic correlations for development, suggesting there may be genetic constraints on the evolution of developmental plasticity.

  10. Lichen secondary metabolites affect growth of Physcomitrella patens by allelopathy.

    PubMed

    Goga, Michal; Antreich, Sebastian J; Bačkor, Martin; Weckwerth, Wolfram; Lang, Ingeborg

    2016-09-19

    Lichen secondary metabolites can function as allelochemicals and affect the development and growth of neighboring bryophytes, fungi, vascular plants, microorganisms, and even other lichens. Lichen overgrowth on bryophytes is frequently observed in nature even though mosses grow faster than lichens, but there is still little information on the interactions between lichens and bryophytes.In the present study, we used extracts from six lichen thalli containing secondary metabolites like usnic acid, protocetraric acid, atranorin, lecanoric acid, nortistic acid, and thamnolic acid. To observe the influence of these metabolites on bryophytes, the moss Physcomitrella patens was cultivated for 5 weeks under laboratory conditions and treated with lichen extracts. Toxicity of natural mixtures of secondary metabolites was tested at three selected doses (0.001, 0.01, and 0.1 %). When the mixture contained substantial amounts of usnic acid, we observed growth inhibition of protonemata and reduced development of gametophores. Significant differences in cell lengths and widths were also noticed. Furthermore, usnic acid had a strong effect on cell division in protonemata suggesting a strong impact on the early stages of bryophyte development by allelochemicals contained in the lichen secondary metabolites.Biological activities of lichen secondary metabolites were confirmed in several studies such as antiviral, antibacterial, antitumor, antiherbivore, antioxidant, antipyretic, and analgetic action or photoprotection. This work aimed to expand the knowledge on allelopathic effects on bryophyte growth.

  11. Larval intraspecific competition for food in the European grapevine moth Lobesia botrana.

    PubMed

    Thiéry, D; Monceau, K; Moreau, J

    2014-08-01

    Effective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

  12. Do plastic particles affect microalgal photosynthesis and growth?

    PubMed

    Sjollema, Sascha B; Redondo-Hasselerharm, Paula; Leslie, Heather A; Kraak, Michiel H S; Vethaak, A Dick

    2016-01-01

    The unbridled increase in plastic pollution of the world's oceans raises concerns about potential effects these materials may have on microalgae, which are primary producers at the basis of the food chain and a major global source of oxygen. Our current understanding about the potential modes and mechanisms of toxic action that plastic particles exert on microalgae is extremely limited. How effects might vary with particle size and the physico-chemical properties of the specific plastic material in question are equally unelucidated, but may hold clues to how toxicity, if observed, is exerted. In this study we selected polystyrene particles, both negatively charged and uncharged, and three different sizes (0.05, 0.5 and 6μm) for testing the effects of size and material properties. Microalgae were exposed to different polystyrene particle sizes and surface charges for 72h. Effects on microalgal photosynthesis and growth were determined by pulse amplitude modulation fluorometry and flow cytometry, respectively. None of the treatments tested in these experiments had an effect on microalgal photosynthesis. Microalgal growth was negatively affected (up to 45%) by uncharged polystyrene particles, but only at high concentrations (250mg/L). Additionally, these adverse effects were demonstrated to increase with decreasing particle size.

  13. Family poverty affects the rate of human infant brain growth.

    PubMed

    Hanson, Jamie L; Hair, Nicole; Shen, Dinggang G; Shi, Feng; Gilmore, John H; Wolfe, Barbara L; Pollak, Seth D

    2013-01-01

    Living in poverty places children at very high risk for problems across a variety of domains, including schooling, behavioral regulation, and health. Aspects of cognitive functioning, such as information processing, may underlie these kinds of problems. How might poverty affect the brain functions underlying these cognitive processes? Here, we address this question by observing and analyzing repeated measures of brain development of young children between five months and four years of age from economically diverse backgrounds (n = 77). In doing so, we have the opportunity to observe changes in brain growth as children begin to experience the effects of poverty. These children underwent MRI scanning, with subjects completing between 1 and 7 scans longitudinally. Two hundred and three MRI scans were divided into different tissue types using a novel image processing algorithm specifically designed to analyze brain data from young infants. Total gray, white, and cerebral (summation of total gray and white matter) volumes were examined along with volumes of the frontal, parietal, temporal, and occipital lobes. Infants from low-income families had lower volumes of gray matter, tissue critical for processing of information and execution of actions. These differences were found for both the frontal and parietal lobes. No differences were detected in white matter, temporal lobe volumes, or occipital lobe volumes. In addition, differences in brain growth were found to vary with socioeconomic status (SES), with children from lower-income households having slower trajectories of growth during infancy and early childhood. Volumetric differences were associated with the emergence of disruptive behavioral problems.

  14. Family Poverty Affects the Rate of Human Infant Brain Growth

    PubMed Central

    Hanson, Jamie L.; Hair, Nicole; Shen, Dinggang G.; Shi, Feng; Gilmore, John H.; Wolfe, Barbara L.; Pollak, Seth D.

    2013-01-01

    Living in poverty places children at very high risk for problems across a variety of domains, including schooling, behavioral regulation, and health. Aspects of cognitive functioning, such as information processing, may underlie these kinds of problems. How might poverty affect the brain functions underlying these cognitive processes? Here, we address this question by observing and analyzing repeated measures of brain development of young children between five months and four years of age from economically diverse backgrounds (n = 77). In doing so, we have the opportunity to observe changes in brain growth as children begin to experience the effects of poverty. These children underwent MRI scanning, with subjects completing between 1 and 7 scans longitudinally. Two hundred and three MRI scans were divided into different tissue types using a novel image processing algorithm specifically designed to analyze brain data from young infants. Total gray, white, and cerebral (summation of total gray and white matter) volumes were examined along with volumes of the frontal, parietal, temporal, and occipital lobes. Infants from low-income families had lower volumes of gray matter, tissue critical for processing of information and execution of actions. These differences were found for both the frontal and parietal lobes. No differences were detected in white matter, temporal lobe volumes, or occipital lobe volumes. In addition, differences in brain growth were found to vary with socioeconomic status (SES), with children from lower-income households having slower trajectories of growth during infancy and early childhood. Volumetric differences were associated with the emergence of disruptive behavioral problems. PMID:24349025

  15. Larval and Post-Larval Stages of Pacific Oyster (Crassostrea gigas) Are Resistant to Elevated CO2

    PubMed Central

    R, Dineshram; Dennis, Choi K. S.; Adela, Li J.; Yu, Ziniu; Thiyagarajan, Vengatesen

    2013-01-01

    The average pH of surface oceans has decreased by 0.1 unit since industrialization and is expected to decrease by another 0.3–0.7 units before the year 2300 due to the absorption of anthropogenic CO2. This human-caused pH change is posing serious threats and challenges to the Pacific oyster (Crassostrea gigas), especially to their larval stages. Our knowledge of the effect of reduced pH on C. gigas larvae presently relies presumptively on four short-term (<4 days) survival and growth studies. Using multiple physiological measurements and life stages, the effects of long-term (40 days) exposure to pH 8.1, 7.7 and 7.4 on larval shell growth, metamorphosis, respiration and filtration rates at the time of metamorphosis, along with the juvenile shell growth and structure of the C. gigas, were examined in this study. The mean survival and growth rates were not affected by pH. The metabolic, feeding and metamorphosis rates of pediveliger larvae were similar, between pH 8.1 and 7.7. The pediveligers at pH 7.4 showed reduced weight-specific metabolic and filtration rates, yet were able to sustain a more rapid post-settlement growth rate. However, no evidence suggested that low pH treatments resulted in alterations to the shell ultrastructures (SEM images) or elemental compositions (i.e., Mg/Ca and Sr/Ca ratios). Thus, larval and post-larval forms of the C. gigas in the Yellow Sea are probably resistant to elevated CO2 and decreased near-future pH scenarios. The pre-adapted ability to resist a wide range of decreased pH may provide C. gigas with the necessary tolerance to withstand rapid pH changes over the coming century. PMID:23724027

  16. Larval and post-larval stages of Pacific oyster (Crassostrea gigas) are resistant to elevated CO2.

    PubMed

    Ginger, Ko W K; Vera, Chan B S; R, Dineshram; Dennis, Choi K S; Adela, Li J; Yu, Ziniu; Thiyagarajan, Vengatesen

    2013-01-01

    The average pH of surface oceans has decreased by 0.1 unit since industrialization and is expected to decrease by another 0.3-0.7 units before the year 2300 due to the absorption of anthropogenic CO2. This human-caused pH change is posing serious threats and challenges to the Pacific oyster (Crassostrea gigas), especially to their larval stages. Our knowledge of the effect of reduced pH on C. gigas larvae presently relies presumptively on four short-term (<4 days) survival and growth studies. Using multiple physiological measurements and life stages, the effects of long-term (40 days) exposure to pH 8.1, 7.7 and 7.4 on larval shell growth, metamorphosis, respiration and filtration rates at the time of metamorphosis, along with the juvenile shell growth and structure of the C. gigas, were examined in this study. The mean survival and growth rates were not affected by pH. The metabolic, feeding and metamorphosis rates of pediveliger larvae were similar, between pH 8.1 and 7.7. The pediveligers at pH 7.4 showed reduced weight-specific metabolic and filtration rates, yet were able to sustain a more rapid post-settlement growth rate. However, no evidence suggested that low pH treatments resulted in alterations to the shell ultrastructures (SEM images) or elemental compositions (i.e., Mg/Ca and Sr/Ca ratios). Thus, larval and post-larval forms of the C. gigas in the Yellow Sea are probably resistant to elevated CO2 and decreased near-future pH scenarios. The pre-adapted ability to resist a wide range of decreased pH may provide C. gigas with the necessary tolerance to withstand rapid pH changes over the coming century.

  17. Effect of larval growth conditions on adult body mass and long-distance flight endurance in a wood-boring beetle: Do smaller beetles fly better?

    PubMed

    Brown, Stav; Soroker, Victoria; Ribak, Gal

    2017-02-22

    The tropical fig borer, Batocera rufomaculata De Geer, is a large beetle that is a pest on a number of fruit trees, including fig and mango. Adults feed on the leaves and twigs and females lay their eggs under the bark of the tree. The larvae bore into the tree trunk, causing substantial damage that may lead to the collapse and death of the host tree. We studied how larval development under inferior feeding conditions (experienced during development in dying trees) affects flight endurance in the adult insect. We grew larvae either in their natural host or on sawdust enriched with stale fig tree twigs. Flight endurance of the adults was measured using a custom-built flight-mill. Beetles emerging from the natural host were significantly larger but flew shorter distances than beetles reared on less favourable substrates. There was no difference in the allometric slope of wing area with body mass between the beetles groups; however flight muscle mass scaled with total body mass with an exponent significantly lower than 1.0. Hence, smaller beetles had proportionally larger flight muscles. These findings suggest that beetles that developed smaller as a result from poor nutritional conditions in deteriorating hosts, are better equipped to fly longer distances in search of a new host tree.

  18. Larval development of Phoronis pallida (Phoronida): implications for morphological convergence and divergence among larval body plans.

    PubMed

    Santagata, Scott

    2004-03-01

    Morphological variation among larval body plans must be placed into a phylogenetic and ecological context to assess whether similar morphologies are the result of phylogenetic constraints or convergent selective pressures. Investigations are needed of the diverse larval forms within the Lophotrochozoa, especially the larvae of phoronids and brachiopods. The actinotroch larva of Phoronis pallida (Phoronida) was reared in the laboratory to metamorphic competence. Larval development and growth were followed with video microscopy, SEM, and confocal microscopy. Early developmental features were similar to other phoronid species. Gastrulation was accomplished by embolic invagination of the vegetal hemisphere. Mesenchymal cells were found in the remaining blastocoelic space after invagination began. Mesenchymal cells formed the body wall musculature during the differentiation of larval features. Body wall musculature served as the framework from which all other larval muscles proliferated. Larval growth correlated best with developmental stage rather than age. Consistent with other phoronid species, differentiation of juvenile tissues occurred most rapidly at the latest stages of larval development. The minimum precompetency period of P. pallida was estimated to be approximately 4-6 weeks. Previously published studies have documented that the planktonic embryos of P. pallida develop faster than the brooded embryos of P. vancouverensis. However, these data showed that the difference in developmental rate between the two species decreased in succeeding larval stages. There may be convergent selective pressures that result in similar timing to metamorphic competence among phoronid and brachiopod planktotrophic larval types. Morphological differences between these larval types result from heterochronic developmental shifts in the differentiation of juvenile tissue. Similarities in the larval morphology of phoronids and basal deuterostomes are likely the result of functional

  19. Larval exposure to 4-nonylphenol and 17β-estradiol affects physiological and behavioral development of seawater adaptation in Atlantic salmon smolts

    USGS Publications Warehouse

    Lerner, Darrren T.; Bjornsson, Bjorn Thrandur; McCormick, Stephen D.

    2007-01-01

    Population declines of anadromous salmonids are attributed to anthropogenic disturbances including dams, commercial and recreational fisheries, and pollutants, such as estrogenic compounds. Nonylphenol (NP), a xenoestrogen, is widespread in the aquatic environment due to its use in agricultural, industrial, and household products. We exposed Atlantic salmon yolk-sac larvae to waterborne 10 or 100 μg L-1 NP (NP-L or NP-H, respectively), 2 μg L-1 17β-estradiol (E2), or vehicle, for 21 days to investigate their effects on smolt physiology and behavior 1 year later. NP-H caused approximately 50% mortality during exposure, 30 days after exposure, and 60 days after exposure. Mortality rates of NP-L and E2 fish were not affected until 60 days after treatment, when they were 4-fold greater than those of controls. Treatment with NP-L or E2 as yolk-sac larvae decreased gill sodium-potassium-activated adenosine triphosphatase (Na+,K+-ATPase) activity and seawater (SW) tolerance during smolt development, 1 year after exposure. Exposure to NP-L and E2 resulted in a latency to enter SW and reduced preference for SW approximately 2- and 5-fold, respectively. NP-L-exposed fish had 20% lower plasma insulin-like growth factor I (IGF-I) levels and 35% lower plasma triiodothyronine (T3). Plasma growth hormone and thyroxine (T4) were unaffected. Exposure to E2 did not affect plasma levels of IGF-I, GH, T3, or T4. Both treatment groups exhibited increased plasma cortisol and decreased osmoregulatory capacity in response to a handling stressor. These results suggest that early exposure to environmentally relevant concentrations of NP, and other estrogenic compounds, can cause direct and delayed mortalities and that this exposure can have long term, “organizational” effects on life-history events in salmonids.

  20. Effects of temperature, density and food quality on larval growth and metamorphosis in the north African green frog Pelophylax saharicus.

    PubMed

    Bellakhal, Meher; Neveu, André; Fartouna-Bellakhal, Mouna; Missaoui, Hechmi; Aleya, Lotfi

    2014-10-01

    The ectodermic status of Amphibians explains their heavy dependence at ambient temperatures and thus their sensitivity to global warming. Temperature is likely the main factor regulating their physiology by acting on the endocrine system, with consequences on development, growth and size at metamorphosis. All these parameters control survival in the wild and performances in raniculture. This study is, to our knowledge, the first report on the effects of temperature, density and protein level in food on the rearing of the North African green Frog Pelophylax saharicus. Results show that a temperature of 26 °C is optimal for maximum weight gain. The maximum metamorphosis rate is obtained between 24 and 26 °C. The highest yields occur at low densities from 1 to 10 tadpolesl(-1). The best survival rate and accelerated metamorphosis are obtained at a level of 35% protein in food whose impact on food intake and weight gain is low. The maximum weight attained by tadpoles at metamorphosis, however, is obtained with a level of 40% protein. These results justify examination of this species in the light of climate change and suggest new techniques for aquaculture.

  1. Does Training Affect Growth? Answers to Common Questions.

    ERIC Educational Resources Information Center

    Daly, Robin M.; Bass, Shona; Caine, Dennis; Howe, Warren

    2002-01-01

    Adolescent athletes may be at risk of restricted growth and delayed maturation when combining intense training with insufficient energy intake. Because catch-up growth commonly occurs with reduced training, final adult stature is generally not compromised. However, in athletes with long-term, clinically delayed maturation, catch-up growth may be…

  2. Effects of drought stressed cotton, Gossypium hirsutum L., on beet armyworm, Spodoptera exigua (Hübner), oviposition, and larval feeding preferences and growth.

    PubMed

    Showler, Allan T; Moran, Patrick J

    2003-09-01

    The beet armyworm, Spodoptera exigua (Hübner), has been anecdotally reported to oviposit more on drought stressed than on nonstressed cotton plants. Using potted cotton plants in cages, this study demonstrated that beet armyworms deposited 3.3, 4.6, and 2.3 times more (P < or = 0.05) eggs on cotton plants that were grown on 1500, 1000, and 750 ml water/wk, respectively, than on cotton plants grown in well watered (4000 ml water/wk) soil. Third instars, however, showed no preference for stressed cotton foliage over nonstressed foliage. Third instar beet armyworms raised on well watered cotton plants were 1.5, 2.3, and 2.6 times heavier than those reared on cotton grown in the 1500, 1000, and 750 ml water/wk plants (P < or = 0.05), respectively. Physiochemical analyses showed that drought stressed leaves had significantly greater accumulations of free amino acids that are essential for insect growth and development. Soluble protein and soluble carbohydrates were also more abundant in stressed leaves compared to nonstressed leaves. Despite the apparent increase in nutritional quality in drought stressed plants, larval survival was reduced, probably because the limiting factor became water. Greater amounts of cotton leaf area were consumed from drought stressed leaves (P < or = 0.05) than from nonstressed leaves, probably because the larvae had to metabolize greater portions of assimilated energy to supplement body water with metabolic water derived from respiration. The association of greater host plant nutritional quality to oviposition preference, and conversely, to reduced survivorship, is discussed.

  3. Effects of ocean acidification driven by elevated CO2 on larval shell growth and abnormal rates of the venerid clam, Mactra veneriformis

    NASA Astrophysics Data System (ADS)

    Kim, Jee-Hoon; Yu, Ok Hwan; Yang, Eun Jin; Kang, Sung-Ho; Kim, Won; Choy, Eun Jung

    2016-11-01

    The venerid clam ( Mactra veneriformis Reeve 1854) is one of the main cultured bivalve species in intertidal and shallow subtidal ecosystems along the west coast of Korea. To understand the effects of ocean acidification on the early life stages of Korean clams, we investigated shell growth and abnormality rates and types in the D-shaped, umbonate veliger, and pediveliger stages of the venerid clam M. veneriformis during exposure to elevated seawater pCO2. In particular, we examined abnormal types of larval shell morphology categorized as shell deformations, shell distortions, and shell fissures. Specimens were incubated in seawater equilibrated with bubbled CO2-enriched air at (400±25)×10-6 (ambient control), (800±25)×10-6 (high pCO2), or (1 200±28)×10-6 (extremely high pCO2), the atmospheric CO2 concentrations predicted for the years 2014, 2084, and 2154 (70-year intervals; two human generations), respectively, in the Representative Concentration Pathway (RCP) 8.5 scenario. The mean shell lengths of larvae were significantly decreased in the high and extremely high pCO2 groups compared with the ambient control groups. Furthermore, under high and extremely high pCO2 conditions, the cultures exhibited significantly increased abundances of abnormal larvae and increased severity of abnormalities compared with the ambient control. In the umbonate veliger stage of the experimental larvae, the most common abnormalities were shell deformations, distortions, and fissures; on the other hand, convex hinges and mantle protuberances were absent. These results suggest that elevated CO2 exerts an additional burden on the health of M. veneriformis larvae by impairing early development.

  4. 'Peer pressure' in larval Drosophila?

    PubMed

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-06-06

    Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on 'peer pressure', that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila.

  5. Development of the Larval Amphibian Growth and Development Assay: effects of chronic 4-tert-octylphenol or 17β-trenbolone exposure in Xenopus laevis from embryo to juvenile.

    PubMed

    Haselman, Jonathan T; Kosian, Patricia A; Korte, Joseph J; Olmstead, Allen W; Iguchi, Taisen; Johnson, Rodney D; Degitz, Sigmund J

    2016-12-01

    The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized test guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of the Environment. The LAGDA was designed to evaluate apical effects of chronic chemical exposure on growth, thyroid-mediated amphibian metamorphosis and reproductive development. During the validation phase, two well-characterized endocrine-disrupting chemicals were tested to evaluate the performance of the initial assay design: xenoestrogen 4-tert-octylphenol (tOP) and xenoandrogen 17β-trenbolone (TB). Xenopus laevis embryos were exposed, in flow-through conditions, to tOP (nominal concentrations: 0.0, 6.25, 12.5, 25 and 50 µg l(-1) ) or TB (nominal concentrations: 0.0, 12.5, 25, 50 and 100 ng l(-1) ) until 8 weeks post-metamorphosis, at which time growth measurements were taken, and histopathology assessments were made of the gonads, reproductive ducts, liver and kidneys. There were no effects on growth in either study and no signs of overt toxicity, sex reversal or gonad dysgenesis. Exposure to tOP caused a treatment-related decrease in circulating thyroxine and an increase in thyroid follicular cell hypertrophy and hyperplasia (25 and 50 µg l(-1) ) during metamorphosis. Müllerian duct development was affected after exposure to both chemicals; tOP exposure caused dose-dependent maturation of oviducts in both male and female frogs, whereas TB exposure caused accelerated Müllerian duct regression in males and complete regression in >50% of the females in the 100 ng l(-1) treatment. Based on these results, the LAGDA performed adequately to evaluate apical effects of chronic exposure to two endocrine-active compounds and is the first standardized amphibian multiple life stage toxicity test to date. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  6. Organizational Career Growth, Affective Occupational Commitment and Turnover Intentions

    ERIC Educational Resources Information Center

    Weng, Qingxiong; McElroy, James C.

    2012-01-01

    Survey data, collected from the People's Republic of China, were used to test Weng's (2010) four facet model of career growth and to examine its effect on occupational commitment and turnover intentions. Weng conceptualized career growth as consisting of four factors: career goal progress, professional ability development, promotion speed, and…

  7. Stage-Specific Changes in Physiological and Life-History Responses to Elevated Temperature and Pco2 during the Larval Development of the European Lobster Homarus gammarus (L.).

    PubMed

    Small, Daniel P; Calosi, Piero; Boothroyd, Dominic; Widdicombe, Steve; Spicer, John I

    2015-01-01

    An organism's physiological processes form the link between its life-history traits and the prevailing environmental conditions, especially in species with complex life cycles. Understanding how these processes respond to changing environmental conditions, thereby affecting organismal development, is critical if we are to predict the biological implications of current and future global climate change. However, much of our knowledge is derived from adults or single developmental stages. Consequently, we investigated the metabolic rate, organic content, carapace mineralization, growth, and survival across each larval stage of the European lobster Homarus gammarus, reared under current and predicted future ocean warming and acidification scenarios. Larvae exhibited stage-specific changes in the temperature sensitivity of their metabolic rate. Elevated Pco2 increased C∶N ratios and interacted with elevated temperature to affect carapace mineralization. These changes were linked to concomitant changes in survivorship and growth, from which it was concluded that bottlenecks were evident during H. gammarus larval development in stages I and IV, the transition phases between the embryonic and pelagic larval stages and between the larval and megalopa stages, respectively. We therefore suggest that natural changes in optimum temperature during ontogeny will be key to larvae survival in a future warmer ocean. The interactions of these natural changes with elevated temperature and Pco2 significantly alter physiological condition and body size of the last larval stage before the transition from a planktonic to a benthic life style. Thus, living and growing in warm, hypercapnic waters could compromise larval lobster growth, development, and recruitment.

  8. Sequential acquisition of cacophony calcium currents, sodium channels and voltage-dependent potassium currents affects spike shape and dendrite growth during postembryonic maturation of an identified Drosophila motoneuron.

    PubMed

    Ryglewski, Stefanie; Kilo, Lukas; Duch, Carsten

    2014-05-01

    During metamorphosis the CNS undergoes profound changes to accommodate the switch from larval to adult behaviors. In Drosophila and other holometabolous insects, adult neurons differentiate either from respecified larval neurons, newly born neurons, or are born embryonically but remain developmentally arrested until differentiation during pupal life. This study addresses the latter in the identified Drosophila flight motoneuron 5. In situ patch-clamp recordings, intracellular dye fills and immunocytochemistry address the interplay between dendritic shape, excitability and ionic current development. During pupal life, changes in excitability and spike shape correspond to a stereotyped, progressive appearance of voltage-gated ion channels. High-voltage-activated calcium current is the first current to appear at pupal stage P4, prior to the onset of dendrite growth. This is followed by voltage-gated sodium as well as transient potassium channel expression, when first dendrites grow, and sodium-dependent action potentials can be evoked by somatic current injection. Sustained potassium current appears later than transient potassium current. During the early stages of rapid dendritic growth, sodium-dependent action potentials are broadened by a calcium component. Narrowing of spike shape coincides with sequential increases in transient and sustained potassium currents during stages when dendritic growth ceases. Targeted RNAi knockdown of pupal calcium current significantly reduces dendritic growth. These data indicate that the stereotyped sequential acquisition of different voltage-gated ion channels affects spike shape and excitability such that activity-dependent calcium influx serves as a partner of genetic programs during critical stages of motoneuron dendrite growth.

  9. Metacommunity patterns in larval odonates.

    PubMed

    McCauley, Shannon J; Davis, Christopher J; Relyea, Rick A; Yurewicz, Kerry L; Skelly, David K; Werner, Earl E

    2008-11-01

    The growth of metacommunity ecology as a subdiscipline has increased interest in how processes at different spatial scales structure communities. However, there is still a significant knowledge gap with respect to relating the action of niche- and dispersal-assembly mechanisms to observed species distributions across gradients. Surveys of the larval dragonfly community (Odonata: Anisoptera) in 57 lakes and ponds in southeast Michigan were used to evaluate hypotheses about the processes regulating community structure in this system. We considered the roles of both niche- and dispersal-assembly processes in determining patterns of species richness and composition across a habitat gradient involving changes in the extent of habitat permanence, canopy cover, area, and top predator type. We compared observed richness patterns and species distributions in this system to patterns predicted by four general community models: species sorting related to adaptive trade-offs, a developmental constraints hypothesis, dispersal assembly, and a neutral community assemblage. Our results supported neither the developmental constraints nor the neutral-assemblage models. Observed patterns of richness and species distributions were consistent with patterns expected when adaptive tradeoffs and dispersal-assembly mechanisms affect community structure. Adaptive trade-offs appeared to be important in limiting the distributions of species which segregate across the habitat gradient. However, dispersal was important in shaping the distributions of species that utilize habitats with a broad range of hydroperiods and alternative top predator types. Our results also suggest that the relative importance of these mechanisms may change across this habitat gradient and that a metacommunity perspective which incorporates both niche- and dispersal-assembly processes is necessary to understand how communities are organized.

  10. EFFECTS OF AMMONIUM SULFATE ON GROWTH OF LARVAL NORTHWESTERN SALAMANDERS, RED-LEGGED AND PACIFIC TREEFROG TADPOLES, AND JUVENILE FATHEAD MINNOWS

    EPA Science Inventory

    Ammonium-nitrogen fertilizers are used in large quantities in agricultural areas of the United States, including the grass-seed fields of the Willamette Valley of western Oregon, and are a potential threat to larval amphibians living in the treat areas (Edwards and Daniel 1994, M...

  11. Induction of Larval Settlement in the Reef Coral Porites astreoides by a Cultivated Marine Roseobacter Strain.

    PubMed

    Sharp, K H; Sneed, J M; Ritchie, K B; Mcdaniel, L; Paul, V J

    2015-04-01

    Successful larval settlement and recruitment by corals is critical for the survival of coral reef ecosystems. Several closely related strains of γ-proteobacteria have been identified as cues for coral larval settlement, but the inductive properties of other bacterial taxa naturally occurring in reef ecosystems have not yet been explored. In this study, we assayed bacterial strains representing taxonomic groups consistently detected in corals for their ability to influence larval settlement in the coral Porites astreoides. We identified one α-proteobacterial strain, Roseivivax sp. 46E8, which significantly increased larval settlement in P. astreoides. Logarithmic growth phase (log phase) cell cultures of Roseivivax sp. 46E8 and filtrates (0.22μm) from log phase Roseivivax sp. 46E8 cultures significantly increased settlement, suggesting that an extracellular settlement factor is produced during active growth phase. Filtrates from log phase cultures of two other bacterial isolates, Marinobacter sp. 46E3, and Cytophaga sp. 46B6, also significantly increased settlement, but the cell cultures themselves did not. Monospecific biofilms of the three strains did not result in significant increases in larval settlement. Organic and aqueous/methanol extracts of Roseivivax sp. 46E8 cultures did not affect larval settlement. Examination of filtrates from cell cultures showed that Roseivivax sp. 46E8 spontaneously generated virus-like particles in log and stationary phase growth. Though the mechanism of settlement enhancement by Roseivivax sp. 46E8 is not yet elucidated, our findings point to a new aspect of coral-Roseobacter interactions that should be further investigated, especially in naturally occurring, complex microbial biofilms on reef surfaces.

  12. Minesoil grading and ripping affect black walnut growth and survival

    SciTech Connect

    Josiah, S.J.

    1986-07-01

    In 1980 and 1981, the Botany Department of Southern Illinois University and Sahara Coal Company, Inc. of Harrisburg, Illinois established a series of experimental tree plantings, including black walnut, on a variety of minesoils to explore the effects of different intensities of grading on tree growth. Subsequent walnut stem and root growth were examined during 1985 on five different mine sites: unmined former agricultural land, graded minespoil, replaced (with pan scrapers) topsoil over graded spoil, ripped-graded spoil, and ungraded spoil. Soil bulk density, resistance to penetration, and spoil/soil fertility levels were also measured. The most vigorous trees were found on sites having the lowest soil bulk density and soil strength and lacking horizontal barriers to root growth - the ungraded and ripped sites. Topsoiled sites had the poorest growth and survival, and the greatest stem dieback of any site measured, probably attributable to the confinement of root growth to the upper 15 cm of friable soil above the severely compacted zone. The overall results indicate that most of the minesoil construction techniques examined in this study, which are representative of techniques commonly used in the midwestern US, cause severe minesoil compaction and do not create the proper soil conditions necessary for the survival and vigorous growth of black walnut. Ripping compacted spoil in this and other studies proved to be very effective in alleviating the negative impacts of minesoil compaction. When planning surface mine reclamation activities, ripping should be considered as a possible ameliorative technique when compaction of mined lands is unavoidable and trees are the desired vegetative cover. 4 figures.

  13. Factors affecting plant growth in membrane nutrient delivery

    NASA Technical Reports Server (NTRS)

    Dreschel, T. W.; Wheeler, R. M.; Sager, J. C.; Knott, W. M.

    1990-01-01

    The development of the tubular membrane plant growth unit for the delivery of water and nutrients to roots in microgravity has recently focused on measuring the effects of changes in physical variables controlling solution availability to the plants. Significant effects of membrane pore size and the negative pressure used to contain the solution were demonstrated. Generally, wheat grew better in units with a larger pore size but equal negative pressure and in units with the same pore size but less negative pressure. Lettuce also exhibited better plant growth at less negative pressure.

  14. Larval Exposure to the Juvenile Hormone Analog Pyriproxyfen Disrupts Acceptance of and Social Behavior Performance in Adult Honeybees

    PubMed Central

    Fourrier, Julie; Deschamps, Matthieu; Droin, Léa; Alaux, Cédric; Fortini, Dominique; Beslay, Dominique; Le Conte, Yves; Devillers, James; Aupinel, Pierrick; Decourtye, Axel

    2015-01-01

    Background Juvenile hormone (JH) plays an important role in honeybee development and the regulation of age-related division of labor. However, honeybees can be exposed to insect growth regulators (IGRs), such as JH analogs developed for insect pest and vector control. Although their side effects as endocrine disruptors on honeybee larval or adult stages have been studied, little is known about the subsequent effects on adults of a sublethal larval exposure. We therefore studied the impact of the JH analog pyriproxyfen on larvae and resulting adults within a colony under semi-field conditions by combining recent laboratory larval tests with chemical analysis and behavioral observations. Oral and chronic larval exposure at cumulative doses of 23 or 57 ng per larva were tested. Results Pyriproxyfen-treated bees emerged earlier than control bees and the highest dose led to a significant rate of malformed adults (atrophied wings). Young pyriproxyfen-treated bees were more frequently rejected by nestmates from the colony, inducing a shorter life span. This could be linked to differences in cuticular hydrocarbon (CHC) profiles between control and pyriproxyfen-treated bees. Finally, pyriproxyfen-treated bees exhibited fewer social behaviors (ventilation, brood care, contacts with nestmates or food stocks) than control bees. Conclusion Larval exposure to sublethal doses of pyriproxyfen affected several life history traits of the honeybees. Our results especially showed changes in social integration (acceptance by nestmates and social behaviors performance) that could potentially affect population growth and balance of the colony. PMID:26171610

  15. Dissolved oxygen concentration affects hybrid striped bass growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Management of dissolved oxygen (DO) concentration in ponds at night during the growing season is important because fish growth and yield are greater in ponds with higher nightly DO concentrations. Three studies were conducted to quantify performance traits and metabolic responses of hybrid striped b...

  16. Shade periodicity affects growth of container grown dogwoods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Container-grown dogwoods rank third in the US in nursery sales of ornamental trees. However, Dogwoods are a challenging crop to produce in container culture, especially when bare root liners are used as the initial transplant into containers due unacceptable levels of mortality and poor growth. This...

  17. Phasic temperature change patterns affect growth and tuberization in potatoes

    SciTech Connect

    Cao, W.; Tibbitts, T.W. . Dept. of Horticulture)

    1994-07-01

    This study determined the response of potato (Solanum tuberosum L., cv. Norland) plants to various patterns of air temperature changes over different growth periods. In each of two experiments under controlled environments, eight treatments of temperature changes were carried out in two growth rooms maintained at 17 and 22 C and a constant vapor pressure deficit of 0.60 kPa and 14-hour photoperiod. Plants were grown for 63 days after transplanting of tissue culture plantlets in 20-liter pots containing peat-vermiculite mix. Temperature changes were imposed on days 21 and 42, which were essentially at the beginning of tuber initiation and tuber enlargement, respectively, for this cultivar. Plants were moved between two temperature rooms to obtain eight temperature change patterns: 17-17-17, 17-17-22, 17-22-17, 22-17-17, 17-22-22, 22-17-22, 22-22-17, and 22-22-22C over three 21-day growth periods. At harvest on day 63, total plant dry weight was higher for the treatments beginning with 22 C than for those beginning with 17C, with highest biomass obtained at 22-22-17 and 22-17-17C. Shoot dry weight increased with temperature increased from 17-17-17 to 22-22-22C during the three growth periods. Tuber dry weight was highest with 22-17-17C, and lowest with 17-17-22 and 17-22-22C. With 22-17-17C, both dry weights of stolons and roots were lowest. Total tuber number and number of small tubers were highest with 17-17-17 and 17-17-22C, and lowest with 17-22-22 and 22-22-22C, whereas number of medium tubers was highest with 22-17-22C, and number of large tubers was highest with 22-17-17C. This study indicates that tuber development of potatoes is optimized with a phasic pattern of high temperature during early growth and low temperature during later growth.

  18. Steps in Cu(111) thin films affect graphene growth kinetics

    NASA Astrophysics Data System (ADS)

    Miller, David L.; Gannett, Will; Keller, Mark W.

    2014-03-01

    The kinetics of chemical vapor deposition of graphene on Cu substrates depend on the relative rates of C diffusion on the surface, C attachment to graphene islands, and removal of C from the surface or from graphene islands by etching processes involving H atoms. Using Cu(111) thin films with centimeter-sized grains, we have grown graphene under a variety of conditions and examined the edges of graphene islands with SEM and AFM. The Cu surface shows a series of regular steps, roughly 2 nm in height, and the graphene islands are diamond-shaped with faster growth along the edges of Cu steps. In contrast, growth on polycrystalline Cu foils under the same conditions shows hexagonal graphene islands with smooth edges.

  19. Organic matter loading affects lodgepole pine seedling growth.

    PubMed

    Wei, Xiaohua; Li, Qinglin; Waterhouse, M J; Armleder, H M

    2012-06-01

    Organic matter plays important roles in returning nutrients to the soil, maintaining forest productivity and creating habitats in forest ecosystems. Forest biomass is in increasing demand for energy production, and organic matter has been considered as a potential supply. Thus, an important management question is how much organic matter should be retained after forest harvesting to maintain forest productivity. To address this question, an experimental trial was established in 1996 to evaluate the responses of lodgepole pine seedling growth to organic matter loading treatments. Four organic matter loading treatments were randomly assigned to each of four homogeneous pine sites: removal of all organic matter on the forest floor, organic matter loading quantity similar to whole-tree-harvesting residuals left on site, organic matter loading quantity similar to stem-only-harvesting residuals, and organic matter loading quantity more similar to what would be found in disease- or insect-killed stands. Our 10-year data showed that height and diameter had 29 and 35 % increase, respectively, comparing the treatment with the most organic matter loading to the treatment with the least organic matter loading. The positive response of seedling growth to organic matter loading may be associated with nutrients and/or microclimate change caused by organic matter, and requires further study. The dynamic response of seedling growth to organic matter loading treatments highlights the importance of long-term studies. Implications of those results on organic matter management are discussed in the context of forest productivity sustainability.

  20. Organic Matter Loading Affects Lodgepole Pine Seedling Growth

    NASA Astrophysics Data System (ADS)

    Wei, Xiaohua; Li, Qinglin; Waterhouse, M. J.; Armleder, H. M.

    2012-06-01

    Organic matter plays important roles in returning nutrients to the soil, maintaining forest productivity and creating habitats in forest ecosystems. Forest biomass is in increasing demand for energy production, and organic matter has been considered as a potential supply. Thus, an important management question is how much organic matter should be retained after forest harvesting to maintain forest productivity. To address this question, an experimental trial was established in 1996 to evaluate the responses of lodgepole pine seedling growth to organic matter loading treatments. Four organic matter loading treatments were randomly assigned to each of four homogeneous pine sites: removal of all organic matter on the forest floor, organic matter loading quantity similar to whole-tree-harvesting residuals left on site, organic matter loading quantity similar to stem-only-harvesting residuals, and organic matter loading quantity more similar to what would be found in disease- or insect-killed stands. Our 10-year data showed that height and diameter had 29 and 35 % increase, respectively, comparing the treatment with the most organic matter loading to the treatment with the least organic matter loading. The positive response of seedling growth to organic matter loading may be associated with nutrients and/or microclimate change caused by organic matter, and requires further study. The dynamic response of seedling growth to organic matter loading treatments highlights the importance of long-term studies. Implications of those results on organic matter management are discussed in the context of forest productivity sustainability.

  1. The asymmetrical growth of otoliths in fish is affected by hypergravity.

    NASA Astrophysics Data System (ADS)

    Anken, R. H.; Kappel, T.; Rahmann, H.

    1999-12-01

    Size and asymmetry (size difference between the left and the right side) of inner ear otoliths of larval cichlid fish were determined after a long-term stay at moderate hypergravity conditions (3 g; centrifuge), in the course of which the animals completed their ontogenetic development from hatch to freely swimming. Both the normal morphogenetic development as well as the timely onset and gain of performance of the swimming behaviour was not impaired by the experimental conditions. However, both utricular and saccular otoliths (lapilli and sagittae, respectively) were significantly smaller after hyper- g exposure as compared to parallely raised 1 g control specimens. The asymmetry of sagittae was significantly increased in the experimental animals, whereas the respective asymmetry concerning lapilli was pronouncedly decreased in comparison to the 1 g controls. These findings suggest, that the growth and the development of bilateral asymmetry of otoliths is guided by the environmental gravity vector.

  2. Mexican propolis flavonoids affect photosynthesis and seedling growth.

    PubMed

    King-Díaz, Beatriz; Granados-Pineda, Jessica; Bah, Mustapha; Rivero-Cruz, J Fausto; Lotina-Hennsen, Blas

    2015-10-01

    As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 μM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli.

  3. Ozone affects growth and development of Pieris brassicae on the wild host plant Brassica nigra.

    PubMed

    Khaling, Eliezer; Papazian, Stefano; Poelman, Erik H; Holopainen, Jarmo K; Albrectsen, Benedicte R; Blande, James D

    2015-04-01

    When plants are exposed to ozone they exhibit changes in both primary and secondary metabolism, which may affect their interactions with herbivorous insects. Here we investigated the performance and preferences of the specialist herbivore Pieris brassicae on the wild plant Brassica nigra under elevated ozone conditions. The direct and indirect effects of ozone on the plant-herbivore system were studied. In both cases ozone exposure had a negative effect on P. brassicae development. However, in dual-choice tests larvae preferentially consumed plant material previously fumigated with the highest concentration tested, showing a lack of correlation between larval preference and performance on ozone exposed plants. Metabolomic analysis of leaf material subjected to combinations of ozone and herbivore-feeding, and focussing on known defence metabolites, indicated that P. brassicae behaviour and performance were associated with ozone-induced alterations to glucosinolate and phenolic pools.

  4. Feeding broodstocks different starfish diets affect growth and survival of larvae of trumpet shell ( Charonia lampas sauliae Reeve 1844)

    NASA Astrophysics Data System (ADS)

    Kang, Kyoungho; Kim, Malhee; Hong, Hyeran; Cha, Guyong; Sui, Zhenghong

    2016-10-01

    Trumpet shell ( Charonia lampas sauliae) (Mollusca, Heterogastropoda, Cymatidae) has extensive economic value. Studies on the artificial larval development of C. lampas sauliae for aquaculture utilization have become especially important due to the finite natural resources. In the present study, the growth and survival rate of the larvae of C. lampas sauliae broodstocks fed three types of starfish diets, Asterina pectinifera Müller & Troschel 1842, A. amurensis Lütken 1871 and their mixture were compared. The larval size increased gradually between day 10 and day 20 after hatching at 15°C and 20°C. No difference was found in body size and specific growth rate (SGR) (two-way ANOVA; P > 0.05). However, during transition from trochophore to veliger stage 20 days after hatching, significant increases in larval survival and growth rates were observed. The maximum survival rate was observed on day 10. The mean survival rate was 0.463, 0.730 and 0.515 at 15°C, and 0.369, 0.713 and 0.444 at 20°C when A. pectinifera, A. amurensis and their mixture were fed, respectively. The SGR and survival rate of the larvae were definitely influenced by the diets ( P < 0.05), and the effect of A. amurensis alone was higher than that of A. pectinifera alone and their mixture.

  5. Effects of egg size on success of larval salamanders in complex aquatic environments. [Ambystoma talpoideum

    SciTech Connect

    Semlitsch, R.D. ); Whitfield Gibbons, J. )

    1990-10-01

    Effects of egg size on growth, survival, and metamorphosis of larval salamanders (Ambystoma talpoideum) were examined in varying environments. Pond drying regime and presence vs. absence of an interspecific competitor were manipulated in a factorial experiment using artificial ponds to measure the responses of larvae. Females that were 4 yr old produced larger eggs and hatchlings than 1-yr-old females. Differences in body size at hatching persisted through day 49 of the experiment but disappeared by day 129. Drying regime also affected body size at day 49 but not at day 129. Larvae from large eggs, and larvae in constant water level ponds, had higher survival to day 129 than larvae from small eggs, and in drying ponds. There was also a significant interaction between egg size and drying regime. Larvae from large eggs survived better than larvae from small eggs in the constant water level ponds, but not in drying ponds. Interspecific competitors did not affect growth or survival to day 129. More individuals metamorphosed from drying ponds than from constant water level ponds. The growth advantages conferred by larger body size at hatching are transient and may disappear during compensatory growth later in the larval period. Body size advantages early in the larval period, however, probably account for increased survival through size-specific mechanisms at a time when newly hatched larvae are most vulnerable.

  6. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2017-02-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  7. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2016-10-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  8. Formaldehyde exposure affects growth and metabolism of common bean

    SciTech Connect

    Mutters, R.G.; Madore, M. ); Bytnerowicz, A. )

    1993-01-01

    Recent state and federal directives have slated a substantial increase in the use of methanol as an alternative to gasoline in both fleet and private vehicles in the coming decade. The incomplete combustion of methanol produces formaldehyde vapor, and catalytic converter technology that completely oxidizes formaldehyde has yet to be developed. The approach of this study was to use a range of methanol concentrations encompassing levels currently found or that may occur in the future in the ambient air of some heavily polluted areas to test the potential phytotoxicity of formaldehyde. The study had the following objectives: (1) design and build a formaldehyde vapor generator with sufficient capacity for long-term plant fumigations; (2) determine growth response of common bean to formaldehyde; (3) evaluate physiological and biochemical changes of bean plants associated with formaldehyde exposures. 20 refs., 2 figs., 2 tabs.

  9. Growth of ponderosa pine seedlings as affected by air pollution

    NASA Astrophysics Data System (ADS)

    Momen, B.; Anderson, P. D.; Houpis, J. L. J.; Helms, J. A.

    The effect of air pollution on seedling survival and competitive ability is important to natural and artificial regeneration of forest trees. Although biochemical and physiological processes are sensitive indicators of pollution stress, the cumulative effects of air pollutants on seedling vigor and competitive ability may be assessed directly from whole-plant growth characteristics such as diameter, height, and photosynthetic area. A few studies that have examined intraspecific variation in seedling response to air pollution indicate that genotypic differences are important in assessing potential effects of air pollution on forest regeneration. Here, we studied the effects of acid rain (no-rain, pH 5.1 rain, pH 3.0 rain) and ozone (filtered, ambient, twice-ambient) in the field on height, diameter, volume, the height:diameter ratio, maximum needle length, and time to reach maximum needle length in seedlings of three families of ponderosa pine ( Pinus ponderosa Dougl. ex Laws). Seedling diameter, height, volume, and height:diameter ratio related significantly to their pre-treatment values. Twice-ambient ozone decreased seedling diameter compared with ozone-filtered air. A significant family-by-ozone interaction was detected for seedling height, as the height of only one of the three families was decreased by twice-ambient ozone compared with the ambient level. Seedling diameter was larger and the height:diameter ratio was smaller under pH 3.0 rain compared to either the no-rain or the pH 5.1-rain treatment. This suggests greater seedling vigor, perhaps due to a foliar fertilization effect of the pH 3.0 rain.

  10. Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata

    PubMed Central

    Segev, Ori; Polevikove, Antonina; Blank, Lior; Goedbloed, Daniel; Küpfer, Eliane; Gershberg, Anna; Koplovich, Avi; Blaustein, Leon

    2015-01-01

    Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping – i.e., bites inflicted by predators including conspecifics - on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail) on Near Eastern fire salamander (Salamandra infraimmaculata) larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length) at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample. PMID:26065683

  11. Effects of Tail Clipping on Larval Performance and Tail Regeneration Rates in the Near Eastern Fire Salamander, Salamandra infraimmaculata.

    PubMed

    Segev, Ori; Polevikove, Antonina; Blank, Lior; Goedbloed, Daniel; Küpfer, Eliane; Gershberg, Anna; Koplovich, Avi; Blaustein, Leon

    2015-01-01

    Tail-tip clipping is a common technique for collecting tissue samples from amphibian larvae and adults. Surprisingly, studies of this invasive sampling procedure or of natural tail clipping--i.e., bites inflicted by predators including conspecifics--on the performance and fitness of aquatic larval stages of urodeles are scarce. We conducted two studies in which we assessed the effects of posterior tail clipping (~30 percent of tail) on Near Eastern fire salamander (Salamandra infraimmaculata) larvae. In a laboratory study, we checked regeneration rates of posterior tail-tip clipping at different ages. Regeneration rates were hump-shaped, peaking at the age of ~30 days and then decreasing. This variation in tail regeneration rates suggests tradeoffs in resource allocation between regeneration and somatic growth during early and advanced development. In an outdoor artificial pond experiment, under constant larval densities, we assessed how tail clipping of newborn larvae affects survival to, time to, and size at metamorphosis. Repeated measures ANOVA on mean larval survival per pond revealed no effect of tail clipping. Tail clipping had correspondingly no effect on larval growth and development expressed in size (mass and snout-vent length) at, and time to, metamorphosis. We conclude that despite the given variation in tail regeneration rates throughout larval ontogeny, clipping of 30% percent of the posterior tail area seems to have no adverse effects on larval fitness and survival. We suggest that future use of this imperative tool for the study of amphibian should take into account larval developmental stage during the time of application and not just the relative size of the clipped tail sample.

  12. Temperature affects insulin-like growth factor I and growth of juvenile southern flounder, Paralichthys lethostigma.

    PubMed

    Luckenbach, J Adam; Murashige, Ryan; Daniels, Harry V; Godwin, John; Borski, Russell J

    2007-01-01

    Temperature profoundly influences growth of heterothermic vertebrates. However, few studies have investigated the effects of temperature on growth and insulin-like growth factor I (IGF-I) in fishes. The aim of this study was to examine effects of temperature on growth and establish whether IGF-I may mediate growth at different temperatures in southern flounder, Paralichthys lethostigma. In two experiments, juvenile flounder were reared at 23 and 28 degrees C and growth was monitored for either 117 or 197 days. Growth was similar across treatments in both experiments until fish reached approximately 100 mm total length. Body size then diverged with fish at 23 degrees C ultimately growing 65-83% larger than those at 28 degrees C. Muscle IGF-I mRNA, plasma IGF-I, and hepatosomatic index (HSI) were significantly higher in flounder at 23 degrees C, whereas hepatic IGF-I mRNA abundance did not differ with treatment. Muscle IGF-I mRNA was correlated with HSI, while plasma IGF-I was correlated with body size, hepatic IGF-I mRNA, and HSI. These results demonstrate a strong effect of temperature on flounder growth and show that temperature-induced variation in growth is associated with differences in systemic IGF-I and local (i.e., muscle) IGF-I mRNA levels. The results also support the use of plasma IGF-I and HSI as indicators of flounder growth status.

  13. Alteration of proteoglycan sulfation affects bone growth and remodeling.

    PubMed

    Gualeni, Benedetta; de Vernejoul, Marie-Christine; Marty-Morieux, Caroline; De Leonardis, Fabio; Franchi, Marco; Monti, Luca; Forlino, Antonella; Houillier, Pascal; Rossi, Antonio; Geoffroy, Valerie

    2013-05-01

    Diastrophic dysplasia (DTD) is a chondrodysplasia caused by mutations in the SLC26A2 gene, leading to reduced intracellular sulfate pool in chondrocytes, osteoblasts and fibroblasts. Hence, proteoglycans are undersulfated in the cartilage and bone of DTD patients. To characterize the bone phenotype of this skeletal dysplasia we used the Slc26a2 knock-in mouse (dtd mouse), that was previously validated as an animal model of DTD in humans. X-rays, bone densitometry, static and dynamic histomorphometry, and in vitro studies revealed a primary bone defect in the dtd mouse model. We showed in vivo that this primary bone defect in dtd mice is due to decreased bone accrual associated with a decreased trabecular and periosteal appositional rate at the cell level in one month-old mice. Although the osteoclast number evaluated by histomorphometry was not different in dtd compared to wild-type mice, urine analysis of deoxypyridinoline cross-links and serum levels of type I collagen C-terminal telopeptides showed a higher resorption rate in dtd mice compared to wild-type littermates. Electron microscopy studies showed that collagen fibrils in bone were thinner and less organized in dtd compared to wild-type mice. These data suggest that the low bone mass observed in mutant mice could possibly be linked to the different bone matrix compositions/organizations in dtd mice triggering changes in osteoblast and osteoclast activities. Overall, these results suggest that proteoglycan undersulfation not only affects the properties of hyaline cartilage, but can also lead to unbalanced bone modeling and remodeling activities, demonstrating the importance of proteoglycan sulfation in bone homeostasis.

  14. Alteration of proteoglycan sulfation affects bone growth and remodeling

    PubMed Central

    Gualeni, Benedetta; de Vernejoul, Marie-Christine; Marty-Morieux, Caroline; De Leonardis, Fabio; Franchi, Marco; Monti, Luca; Forlino, Antonella; Houillier, Pascal; Rossi, Antonio; Geoffroy, Valerie

    2013-01-01

    Diastrophic dysplasia (DTD) is a chondrodysplasia caused by mutations in the SLC26A2 gene, leading to reduced intracellular sulfate pool in chondrocytes, osteoblasts and fibroblasts. Hence, proteoglycans are undersulfated in the cartilage and bone of DTD patients. To characterize the bone phenotype of this skeletal dysplasia we used the Slc26a2 knock-in mouse (dtd mouse), that was previously validated as an animal model of DTD in humans. X-rays, bone densitometry, static and dynamic histomorphometry, and in vitro studies revealed a primary bone defect in the dtd mouse model. We showed in vivo that this primary bone defect in dtd mice is due to decreased bone accrual associated with a decreased trabecular and periosteal appositional rate at the cell level in one month-old mice. Although the osteoclast number evaluated by histomorphometry was not different in dtd compared to wild-type mice, urine analysis of deoxypyridinoline cross-links and serum levels of type I collagen C-terminal telopeptides showed a higher resorption rate in dtd mice compared to wild-type littermates. Electron microscopy studies showed that collagen fibrils in bone were thinner and less organized in dtd compared to wild-type mice. These data suggest that the low bone mass observed in mutant mice could possibly be linked to the different bone matrix compositions/organizations in dtd mice triggering changes in osteoblast and osteoclast activities. Overall, these results suggest that proteoglycan undersulfation not only affects the properties of hyaline cartilage, but can also lead to unbalanced bone modeling and remodeling activities, demonstrating the importance of proteoglycan sulfation in bone homeostasis. PMID:23369989

  15. Positive effects of cyanogenic glycosides in food plants on larval development of the common blue butterfly.

    PubMed

    Goverde, Marcel; Bazin, Alain; Kéry, Marc; Shykoff, Jacqui A; Erhardt, Andreas

    2008-09-01

    Cyanogenesis is a widespread chemical defence mechanism in plants against herbivory. However, some specialised herbivores overcome this protection by different behavioural or metabolic mechanisms. In the present study, we investigated the effect of presence or absence of cyanogenic glycosides in birdsfoot trefoil (Lotus corniculatus, Fabaceae) on oviposition behaviour, larval preference, larval development, adult weight and nectar preference of the common blue butterfly (Polyommatus icarus, Lycaenidae). For oviposition behaviour there was a female-specific reaction to cyanogenic glycoside content; i.e. some females preferred to oviposit on cyanogenic over acyanogenic plants, while other females behaved in the opposite way. Freshly hatched larvae did not discriminate between the two plant morphs. Since the two plant morphs differed not only in their content of cyanogenic glycoside, but also in N and water content, we expected these differences to affect larval growth. Contrary to our expectations, larvae feeding on cyanogenic plants showed a faster development and stronger weight gain than larvae feeding on acyanogenic plants. Furthermore, female genotype affected development time, larval and pupal weight of the common blue butterfly. However, most effects detected in the larval phase disappeared for adult weight, indicating compensatory feeding of larvae. Adult butterflies reared on the two cyanogenic glycoside plant morphs did not differ in their nectar preference. But a gender-specific effect was found, where females preferred amino acid-rich nectar while males did not discriminate between the two nectar mimics. The presented results indicate that larvae of the common blue butterfly can metabolise the surplus of N in cyanogenic plants for growth. Additionally, the female-specific behaviour to oviposit preferably on cyanogenic or acyanogenic plant morphs and the female-genotype-specific responses in life history traits indicate the genetic flexibility of this

  16. Evaluating sampling strategies for larval cisco (Coregonus artedi)

    USGS Publications Warehouse

    Myers, J.T.; Stockwell, J.D.; Yule, D.L.; Black, J.A.

    2008-01-01

    To improve our ability to assess larval cisco (Coregonus artedi) populations in Lake Superior, we conducted a study to compare several sampling strategies. First, we compared density estimates of larval cisco concurrently captured in surface waters with a 2 x 1-m paired neuston net and a 0.5-m (diameter) conical net. Density estimates obtained from the two gear types were not significantly different, suggesting that the conical net is a reasonable alternative to the more cumbersome and costly neuston net. Next, we assessed the effect of tow pattern (sinusoidal versus straight tows) to examine if propeller wash affected larval density. We found no effect of propeller wash on the catchability of larval cisco. Given the availability of global positioning systems, we recommend sampling larval cisco using straight tows to simplify protocols and facilitate straightforward measurements of volume filtered. Finally, we investigated potential trends in larval cisco density estimates by sampling four time periods during the light period of a day at individual sites. Our results indicate no significant trends in larval density estimates during the day. We conclude estimates of larval cisco density across space are not confounded by time at a daily timescale. Well-designed, cost effective surveys of larval cisco abundance will help to further our understanding of this important Great Lakes forage species.

  17. Drosophila melanogaster Natural Variation Affects Growth Dynamics of Infecting Listeria monocytogenes

    PubMed Central

    Hotson, Alejandra Guzmán; Schneider, David S.

    2015-01-01

    We find that in a Listeria monocytogenes/Drosophila melanogaster infection model, L. monocytogenes grows according to logistic kinetics, which means we can measure both a maximal growth rate and growth plateau for the microbe. Genetic variation of the host affects both of the pathogen growth parameters, and they can vary independently. Because growth rates and ceilings both correlate with host survival, both properties could drive evolution of the host. We find that growth rates and ceilings are sensitive to the initial infectious dose in a host genotype–dependent manner, implying that experimental results differ as we change the original challenge dose within a single strain of host. PMID:26438294

  18. Growth of Larval Agrilus planipennis (Coleoptera: Buprestidae) and Fitness of Tetrastichus planipennisi (Hymenoptera: Eulophidae) in Blue Ash (Fraxinus quadrangulata) and Green Ash (F. pennsylvanica).

    PubMed

    Peterson, Donnie L; Duan, Jian J; Yaninek, J S; Ginzel, Matthew D; Sadof, Clifford S

    2015-12-01

    Emerald ash borer (Agrilus planipennis Fairmaire) is an invasive primary pest of North American ash (Fraxinus spp.) trees. Blue ash (F. quadrangulata) is less susceptible to emerald ash borer infestations in the forest than other species of North American ash. Whereas other studies have examined adult host preferences, we compared the capacity of emerald ash borer larvae reared from emerald ash borer eggs in the field and in the laboratory to survive and grow in blue ash and the more susceptible green ash (F. pennsylvanica). Emerald ash borer larval survivorship was the same on both ash species. Mortality due to wound periderm formation was only observed in living field grown trees, but was low (<4%) in both green and blue ash. No difference in larval mortality in the absence of natural enemies suggests that both green and blue ash can support the development of emerald ash borer. Larvae reared from eggs on blue ash were smaller than on green ash growing in the field and also in bolts that were infested under laboratory conditions. In a laboratory study, parasitism rates of confined Tetrastichus planipennisi were similar on emerald ash borer larvae reared in blue and green ash bolts, as were fitness measures of the parasitoid including brood size, sex ratio, and adult female size. Thus, we postulate that emerald ash borer larvae infesting blue ash could support populations of T. planipennisi and serve as a potential reservoir for this introduced natural enemy after most of the other native ash trees have been killed.

  19. Foraging and predation risk for larval cisco (Coregonus artedi) in Lake Superior: a modelling synthesis of empirical survey data

    USGS Publications Warehouse

    Myers, Jared T.; Yule, Daniel L.; Jones, Michael L.; Quinlan, Henry R.; Berglund, Eric K.

    2014-01-01

    The relative importance of predation and food availability as contributors to larval cisco (Coregonus artedi) mortality in Lake Superior were investigated using a visual foraging model to evaluate potential predation pressure by rainbow smelt (Osmerus mordax) and a bioenergetic model to evaluate potential starvation risk. The models were informed by observations of rainbow smelt, larval cisco, and zooplankton abundance at three Lake Superior locations during the period of spring larval cisco emergence and surface-oriented foraging. Predation risk was highest at Black Bay, ON, where average rainbow smelt densities in the uppermost 10 m of the water column were >1000 ha−1. Turbid conditions at the Twin Ports, WI-MN, affected larval cisco predation risk because rainbow smelt remained suspended in the upper water column during daylight, placing them alongside larval cisco during both day and night hours. Predation risk was low at Cornucopia, WI, owing to low smelt densities (<400 ha−1) and deep light penetration, which kept rainbow smelt near the lakebed and far from larvae during daylight. In situ zooplankton density estimates were low compared to the values used to develop the larval coregonid bioenergetics model, leading to predictions of negative growth rates for 10 mm larvae at all three locations. The model predicted that 15 mm larvae were capable of attaining positive growth at Cornucopia and the Twin Ports where low water temperatures (2–6 °C) decreased their metabolic costs. Larval prey resources were highest at Black Bay but warmer water temperatures there offset the benefit of increased prey availability. A sensitivity analysis performed on the rainbow smelt visual foraging model showed that it was relatively insensitive, while the coregonid bioenergetics model showed that the absolute growth rate predictions were highly sensitive to input parameters (i.e., 20% parameter perturbation led to order of magnitude differences in model estimates). Our

  20. Katanin p60-like1 promotes microtubule growth and terminal dendrite stability in the larval class IV sensory neurons of Drosophila.

    PubMed

    Stewart, Andrea; Tsubouchi, Asako; Rolls, Melissa M; Tracey, W Daniel; Sherwood, Nina Tang

    2012-08-22

    Dendrite shape is considered a defining component of neuronal function. Yet, the mechanisms specifying diverse dendritic morphologies, and the extent to which their function depends on these morphologies, remain unclear. Here, we demonstrate a requirement for the microtubule-severing protein katanin p60-like 1 (Kat-60L1) in regulating the elaborate dendrite morphology and nocifensive functions of Drosophila larval class IV dendritic arborization neurons. Kat-60L1 mutants exhibit diminished responsiveness to noxious mechanical and thermal stimuli. Class IV dendrite branch number and length are also reduced, supporting a correspondence between neuronal function and the full extent of the dendritic arbor. These arborization defects occur particularly in late larval development, and live imaging reveals that Kat-60L1 is required for dynamic, filopodia-like nascent branches to stabilize during this stage. Mutant dendrites exhibit fewer EB1-GFP-labeled microtubules, suggesting that Kat-60L1 increases polymerizing microtubules to establish terminal branch stability and full arbor complexity. Although loss of the related microtubule-severing protein Spastin also reduces the class IV dendrite arbor, microtubule polymerization within dendrites is unaffected. Conversely, Spastin overexpression destroys stable microtubules within these neurons, while Kat-60L1 has no effect. Kat-60L1 thus sculpts the class IV dendritic arbor through microtubule regulatory mechanisms distinct from Spastin. Our data support differential roles of microtubule-severing proteins in regulating neuronal morphology and function, and provide evidence that dendritic arbor development is the product of multiple pathways functioning at distinct developmental stages.

  1. Plant growth-promoting rhizobacteria affect the growth and nutrient uptake of Fraxinus americana container seedlings.

    PubMed

    Liu, Fangchun; Xing, Shangjun; Ma, Hailin; Du, Zhenyu; Ma, Bingyao

    2013-05-01

    Plant growth-promoting rhizobacteria (PGPR) are important catalysts that regulate the functional properties of agricultural systems. However, there is little information on the effect of PGPR inoculation on the growth and nutrient accumulation of forest container seedlings. This study determined the effects of a growth medium inoculated with PGPR on the nutrient uptake, nutrient accumulation, and growth of Fraxinus americana container seedlings. PGPR inoculation with fertilizer increased the dry matter accumulation of the F. americana aerial parts with delayed seedling emergence time. Under fertilized conditions, the accumulation time of phosphorous (P) and potassium (K) in the F. americana aerial parts was 13 days longer due to PGPR inoculation. PGPR increased the maximum daily P and K accumulations in fertilized seedlings by 9.31 and 10.44 %, respectively, but had little impact on unfertilized ones. Regardless of fertilizer application, the root exudates, namely sugars, amino acids, and organic acids significantly increased because of PGPR inoculation. PGPR inoculation with fertilizer increased the root, shoot, and leaf yields by 19.65, 22.94, and 19.44 %, respectively, as well as the P and K contents by 8.33 and 10.60 %, respectively. Consequently, the N, P, and K uptakes increased by 19.85, 31.97, and 33.95 %, respectively. Hence, PGPR inoculation with fertilizer can be used as a bioenhancer for plant growth and nutrient uptake in forest container seedling nurseries.

  2. Environmental Growth Conditions of Trichoderma spp. Affects Indole Acetic Acid Derivatives, Volatile Organic Compounds, and Plant Growth Promotion.

    PubMed

    Nieto-Jacobo, Maria F; Steyaert, Johanna M; Salazar-Badillo, Fatima B; Nguyen, Dianne Vi; Rostás, Michael; Braithwaite, Mark; De Souza, Jorge T; Jimenez-Bremont, Juan F; Ohkura, Mana; Stewart, Alison; Mendoza-Mendoza, Artemio

    2017-01-01

    Trichoderma species are soil-borne filamentous fungi widely utilized for their many plant health benefits, such as conferring improved growth, disease resistance and abiotic stress tolerance to their hosts. Many Trichoderma species are able to produce the auxin phytohormone indole-3-acetic acid (IAA), and its production has been suggested to promote root growth. Here we show that the production of IAA is strain dependent and diverse external stimuli are associated with its production. In in vitro assays, Arabidopsis primary root length was negatively affected by the interaction with some Trichoderma strains. In soil experiments, a continuum effect on plant growth was shown and this was also strain dependent. In plate assays, some strains of Trichoderma spp. inhibited the expression of the auxin reporter gene DR5 in Arabidopsis primary roots but not secondary roots. When Trichoderma spp. and A. thaliana were physically separated, enhancement of both shoot and root biomass, increased root production and chlorophyll content were observed, which strongly suggested that volatile production by the fungus influenced the parameters analyzed. Trichoderma strains T. virens Gv29.8, T. atroviride IMI206040, T. sp. "atroviride B" LU132, and T. asperellum LU1370 were demonstrated to promote plant growth through volatile production. However, contrasting differences were observed with LU1370 which had a negative effect on plant growth in soil but a positive effect in plate assays. Altogether our results suggest that the mechanisms and molecules involved in plant growth promotion by Trichoderma spp. are multivariable and are affected by the environmental conditions.

  3. Calf and disease factors affecting growth in female Holstein calves in Florida, USA.

    PubMed

    Donovan, G A; Dohoo, I R; Montgomery, D M; Bennett, F L

    1998-01-01

    A prospective cohort study was undertaken to determine calf-level factors that affect performance (growth) between birth and 14 months of age in a convenience sample of approximately 3300 female Holstein calves born in 1991 on two large Florida dairy farms. Data collected on each calf at birth included farm of origin, birth date, weight, height at the pelvis, and serum total protein (a measure of colostral immunoglobulin absorption). Birth season was dichotomized into summer and winter using meteorological data collected by University of Florida Agricultural Research Stations. Data collected at approximately 6 and 14 months of age included age, weight, height at the pelvis, and height at the withers. Growth in weight and stature (height) was calculated for each growth period; growth period 1 (GP1) = birth to 6 months, and growth period 2 (GP2) = 6 to 14 months. Health data collected included data of initial treatment and number of treatments for the diseases diarrhea, omphalitis, septicemia, pneumonia and keratoconjunctivitis. After adjusting for disease occurrence, passive transfer of colostral immunoglobulins had no significant effect on body weight gain or pelvic height growth. Season of birth and occurrence of diarrhea, septicemia and respiratory disease were significant variables decreasing heifer growth (height and weight) in GP1. These variables plus farm, birth weight and exact age when '6 month' data were collected explained 20% and 31% of the variation in body weight gain and pelvic height growth, respectively, in GP1. The number of days treated for pneumonia before 6 months of age significantly decreased average daily weight gain in GP2 (P < 0.025), but did not affect stature growth. Treatment for pneumonia after 6 months of age did not significantly affect weight or height gain after age 6 months. Neither omphalitis nor keratoconjunctivitis explained variability in growth in either of the growth periods.

  4. Larval Temperature–Food Effects on Adult Mosquito Infection and Vertical Transmission of Dengue-1 Virus

    PubMed Central

    Buckner, Eva A.; Alto, Barry W.; Lounibos, L. Philip

    2016-01-01

    Temperature–food interactions in the larval environment can affect life history and population growth of container mosquitoes Aedes aegypti (L.) and Aedes albopictus Skuse, the primary vectors of chikungunya and dengue viruses. We used Ae. aegypti, Ae. albopictus, and dengue-1 virus (DENV-1) from Florida to investigate whether larval rearing temperature can alter the effects of larval food levels on Ae. aegypti and Ae. albopictus life history and DENV-1 infection and vertical transmission. Although we found no effect of larval treatments on survivorship to adulthood, DENV-1 titer, or DENV-1 vertical transmission, rates of vertical transmission up to 16–24% were observed in Ae. albopictus and Ae. aegypti, which may contribute to maintenance of this virus in nature. Larval treatments had no effect on number of progeny and DENV-1 infection in Ae. aegypti, but the interaction between temperature and food affected number of progeny and DENV-1 infection of the female Ae. albopictus parent. The cooler temperature (24°C) yielded the most progeny and this effect was accentuated by high food relative to the other conditions. Low and high food led to the highest (∼90%) and lowest (∼65%) parental infection at the cooler temperature, respectively, whereas intermediate infection rates (∼75–80%) were observed for all food conditions at the elevated temperature. These results suggest that temperature and food availability have minimal influence on rate of vertical transmission and a stronger influence on adults of Ae. albopictus than of Ae. aegypti, which could have consequences for dengue virus epidemiology. PMID:26489999

  5. Tyrosine Phosphorylation and Dephosphorylation in Burkholderia cenocepacia Affect Biofilm Formation, Growth under Nutritional Deprivation, and Pathogenicity.

    PubMed

    Andrade, Angel; Tavares-Carreón, Faviola; Khodai-Kalaki, Maryam; Valvano, Miguel A

    2015-11-20

    Burkholderia cenocepacia, a member of the B. cepacia complex (Bcc), is an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. Tyrosine phosphorylation has emerged as an important posttranslational modification modulating the physiology and pathogenicity of Bcc bacteria. Here, we investigated the predicted bacterial tyrosine kinases BCAM1331 and BceF and the low-molecular-weight protein tyrosine phosphatases BCAM0208, BceD, and BCAL2200 of B. cenocepacia K56-2. We show that BCAM1331, BceF, BCAM0208, and BceD contribute to biofilm formation, while BCAL2200 is required for growth under nutrient-limited conditions. Multiple deletions of either tyrosine kinase or low-molecular-weight protein tyrosine phosphatase genes resulted in the attenuation of B. cenocepacia intramacrophage survival and reduced pathogenicity in the Galleria mellonella larval infection model. Experimental evidence indicates that BCAM1331 displays reduced tyrosine autophosphorylation activity compared to that of BceF. With the artificial substrate p-nitrophenyl phosphate, the phosphatase activities of the three low-molecular-weight protein tyrosine phosphatases demonstrated similar kinetic parameters. However, only BCAM0208 and BceD could dephosphorylate BceF. Further, BCAL2200 became tyrosine phosphorylated in vivo and catalyzed its autodephosphorylation. Together, our data suggest that despite having similar biochemical activities, low-molecular-weight protein tyrosine phosphatases and tyrosine kinases have both overlapping and specific roles in the physiology of B. cenocepacia.

  6. Tyrosine Phosphorylation and Dephosphorylation in Burkholderia cenocepacia Affect Biofilm Formation, Growth under Nutritional Deprivation, and Pathogenicity

    PubMed Central

    Andrade, Angel; Tavares-Carreón, Faviola; Khodai-Kalaki, Maryam

    2015-01-01

    Burkholderia cenocepacia, a member of the B. cepacia complex (Bcc), is an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. Tyrosine phosphorylation has emerged as an important posttranslational modification modulating the physiology and pathogenicity of Bcc bacteria. Here, we investigated the predicted bacterial tyrosine kinases BCAM1331 and BceF and the low-molecular-weight protein tyrosine phosphatases BCAM0208, BceD, and BCAL2200 of B. cenocepacia K56-2. We show that BCAM1331, BceF, BCAM0208, and BceD contribute to biofilm formation, while BCAL2200 is required for growth under nutrient-limited conditions. Multiple deletions of either tyrosine kinase or low-molecular-weight protein tyrosine phosphatase genes resulted in the attenuation of B. cenocepacia intramacrophage survival and reduced pathogenicity in the Galleria mellonella larval infection model. Experimental evidence indicates that BCAM1331 displays reduced tyrosine autophosphorylation activity compared to that of BceF. With the artificial substrate p-nitrophenyl phosphate, the phosphatase activities of the three low-molecular-weight protein tyrosine phosphatases demonstrated similar kinetic parameters. However, only BCAM0208 and BceD could dephosphorylate BceF. Further, BCAL2200 became tyrosine phosphorylated in vivo and catalyzed its autodephosphorylation. Together, our data suggest that despite having similar biochemical activities, low-molecular-weight protein tyrosine phosphatases and tyrosine kinases have both overlapping and specific roles in the physiology of B. cenocepacia. PMID:26590274

  7. Individual and mixture effects of selected pharmaceuticals on larval development of the estuarine shrimp Palaemon longirostris.

    PubMed

    González-Ortegón, Enrique; Blasco, Julian; Nieto, Elena; Hampel, Miriam; Le Vay, Lewis; Giménez, Luis

    2016-01-01

    Few ecotoxicological studies incorporate within the experimental design environmental variability and mixture effects when assessing the impact of pollutants on organisms. We have studied the combined effects of selected pharmaceutical compounds and environmental variability in terms of salinity and temperature on survival, development and body mass of larvae of the estuarine shrimp Palaemon longirostris. Drug residues found in coastal waters occur as mixture, and the evaluation of combined effects of simultaneously occurring compounds is indispensable for their environmental risk assessment. All larval stages of P. longirostris were exposed to the nonsteroidal anti-inflammatory drug (NSAID) diclofenac sodium (DS: 40 and 750 μg L(-1)), the lipid regulator clofibric acid (CA: 17 and 361 μg L(-1)) and the fungicide clotrimazole (CLZ: 0.14 and 4 μg L(-1)). We observed no effect on larval survival of P. longirostris with the tested pharmaceuticals. However, and in contrast to previous studies on larvae of the related marine species Palaemon serratus, CA affected development through an increase in intermoult duration and reduced growth without affecting larval body mass. These developmental effects in P. longirostris larvae were similar to those observed in the mixture of DS and CA confirming the toxic effects of CA. In the case of CLZ, its effects were similar to those observed previously in P. serratus: high doses affected development altering intermoult duration, tended to reduce the number of larval instars and decreased significantly the growth rate. This study suggests that an inter-specific life histories approach should be taken into account to assess the effect of emergent compounds in coastal waters.

  8. Silencing of CYP6 and APN Genes Affects the Growth and Development of Rice Yellow Stem Borer, Scirpophaga incertulas.

    PubMed

    Kola, Vijaya Sudhakara Rao; Renuka, P; Padmakumari, Ayyagari Phani; Mangrauthia, Satendra K; Balachandran, Sena M; Ravindra Babu, V; Madhav, Maganti S

    2016-01-01

    RNAi is a powerful tool to target the insect genes involved in host-pest interactions. Key insect genes are the choice for silencing to achieve pest derived resistance where resistance genes are not available in gene pool of host plant. In this study, an attempt was made to determine the effect of dsRNA designed from two genes Cytochrome P450 derivative (CYP6) and Aminopeptidase N (APN) of rice yellow stem borer (YSB) on growth and development of insect. The bioassays involved injection of chemically synthesized 5' FAM labeled 21-nt dsRNA into rice cut stems and allowing the larvae to feed on these stems which resulted in increased mortality and observed growth and development changes in larval length and weight compared with its untreated control at 12-15 days after treatment. These results were further supported by observing the reduction in transcripts expression of these genes in treated larvae. Fluorescence detection in treated larvae also proved that dsRNA was readily taken by larvae when fed on dsRNA treated stems. These results from the present study clearly show that YSB larvae fed on dsRNA designed from Cytochrome P450 and Aminopeptidase N has detrimental effect on larval growth and development. These genes can be deployed to develop YSB resistance in rice using RNAi approach.

  9. The fish embryo toxicity test as a replacement for the larval growth and survival test: A comparison of test sensitivity and identification of alternative endpoints in zebrafish and fathead minnows.

    PubMed

    Jeffries, Marlo K Sellin; Stultz, Amy E; Smith, Austin W; Stephens, Dane A; Rawlings, Jane M; Belanger, Scott E; Oris, James T

    2015-06-01

    The fish embryo toxicity (FET) test has been proposed as an alternative to the larval growth and survival (LGS) test. The objectives of the present study were to evaluate the sensitivity of the FET and LGS tests in fathead minnows (Pimephales promelas) and zebrafish (Danio rerio) and to determine if the inclusion of sublethal metrics as test endpoints could enhance test utility. In both species, LGS and FET tests were conducted using 2 simulated effluents. A comparison of median lethal concentrations determined via each test revealed significant differences between test types; however, it could not be determined which test was the least and/or most sensitive. At the conclusion of each test, developmental abnormalities and the expression of genes related to growth and toxicity were evaluated. Fathead minnows and zebrafish exposed to mock municipal wastewater-treatment plant effluent in a FET test experienced an increased incidence of pericardial edema and significant alterations in the expression of genes including insulin-like growth factors 1 and 2, heat shock protein 70, and cytochrome P4501A, suggesting that the inclusion of these endpoints could enhance test utility. The results not only show the utility of the fathead minnow FET test as a replacement for the LGS test but also provide evidence that inclusion of additional endpoints could improve the predictive power of the FET test.

  10. The effect of dietary arachidonic acid (ARA) on growth performance, fatty acid composition and expression of ARA metabolism-related genes in larval half-smooth tongue sole (Cynoglossus semilaevis).

    PubMed

    Yuan, Yuhui; Li, Songlin; Mai, Kangsen; Xu, Wei; Zhang, Yanjiao; Ai, Qinghui

    2015-05-28

    The present study was conducted to investigate the effects of dietary arachidonic acid (ARA) on growth performance, fatty acid composition and ARA metabolism-related gene expression in larval half-smooth tongue sole (Cynoglossus semilaevis). Larvae (35 d after hatching, 54 (SEM 1) mg) were fed diets with graded concentrations of ARA (0.01, 0.39, 0.70, 1.07, 1.42 and 2.86 % dry weight) five times per d to apparent satiation for 30 d. Results showed that increased dietary ARA concentration caused a significant non-linear rise to a plateau in survival rate, final body weight and thermal growth coefficient, and the maximum values occurred with the 1.42 % ARA treatment. As dietary ARA increased to 1.07 or 1.42 %, activities of trypsin, leucine aminopeptidase and alkaline phosphatase levels increased, but they decreased with higher ARA concentrations. The fatty acid composition of tongue sole larvae was almost well correlated with their dietary fatty acid profiles, and the EPA content of the larvae decreased with increasing dietary ARA. Meanwhile, the partial sequences of COX-1a (cyclo-oxygenase-1a), COX-1b (cyclo-oxygenase-1b), COX-2 (cyclo-oxygenase-2), 5-LOX (5-lipoxygenase) and CYP2J6-like (cytochrome P450 2J6-like) were also obtained. Both COX-2 and 5-LOX mRNA expression levels significantly increased to a plateau in an 'L'-shaped manner as dietary ARA increased to 1.07 or 1.42 %, but no significant differences were found in the gene expression of COX-1a, COX-1b or CYP2J6-like. These results suggest that 1.07-1.42 % dietary ARA was beneficial to the growth performance of larval tongue sole, and the regulation of dietary ARA on the growth performance of larvae was probably involved in altering the mRNA expression of COX-2 and 5-LOX.

  11. Soil type affects Pinus ponderosa var. scopulorum (Pinaceae) seedling growth in simulated drought experiments1

    PubMed Central

    Lindsey, Alexander J.; Kilgore, Jason S.

    2013-01-01

    • Premise of the study: Effects of drought stress and media type interactions on growth of Pinus ponderosa var. scopulorum germinants were investigated. • Methods and Results: Soil properties and growth responses under drought were compared across four growth media types: two native soils (dolomitic limestone and granite), a soil-less industry standard conifer medium, and a custom-mixed conifer medium. After 35 d of growth, the seedlings under drought stress (reduced watering) produced less shoot and root biomass than watered control seedlings. Organic media led to decreased root biomass, but increased root length and shoot biomass relative to the mineral soils. • Conclusions: Media type affected root-to-shoot biomass partitioning of P. ponderosa var. scopulorum, which may influence net photosynthetic rates, growth, and long-term seedling survival. Further work should examine how specific soil properties like bulk density and organic matter influence biomass allocation in greenhouse studies. PMID:25202578

  12. Disruption of the lower food web in Lake Ontario: Did it affect alewife growth or condition?

    USGS Publications Warehouse

    O'Gorman, R.; Prindle, S.E.; Lantry, J.R.; Lantry, B.F.

    2008-01-01

    From the early 1980s to the late 1990s, a succession of non-native invertebrates colonized Lake Ontario and the suite of consequences caused by their colonization became known as "food web disruption". For example, the native burrowing amphipod Diporeia spp., a key link in the profundal food web, declined to near absence, exotic predaceous cladocerans with long spines proliferated, altering the zooplankton community, and depth distributions of fishes shifted. These changes had the potential to affect growth and condition of planktivorous alewife Alosa pseudoharengus, the most abundant fish in the lake. To determine if food web disruption affected alewife, we used change-point analysis to examine alewife growth and adult alewife condition during 1976-2006 and analysis-of-variance to determine if values between change points differed significantly. There were no change points in growth during the first year of life. Of three change points in growth during the second year of life, one coincided with the shift in springtime distribution of alewife to deeper water but it was not associated with a significant change in growth. After the second year of life, no change points in growth were evident, although growth in the third year of life spiked in those years when Bythotrephes, the largest of the exotic cladocerans, was abundant suggesting that it was a profitable prey item for age-2 fish. We detected two change points in condition of adult alewife in fall, but the first occurred in 1981, well before disruption began. A second change point occurred in 2003, well after disruption began. After the springtime distribution of alewife shifted deeper during 1992-1994, growth in the first two years of life became more variable, and growth in years of life two and older became correlated (P < 0.05). In conclusion, food web disruption had no negative affect on growth and condition of alewife in Lake Ontario although it appears to have resulted in growth in the first two years of

  13. Environmental Growth Conditions of Trichoderma spp. Affects Indole Acetic Acid Derivatives, Volatile Organic Compounds, and Plant Growth Promotion

    PubMed Central

    Nieto-Jacobo, Maria F.; Steyaert, Johanna M.; Salazar-Badillo, Fatima B.; Nguyen, Dianne Vi; Rostás, Michael; Braithwaite, Mark; De Souza, Jorge T.; Jimenez-Bremont, Juan F.; Ohkura, Mana; Stewart, Alison

    2017-01-01

    Trichoderma species are soil-borne filamentous fungi widely utilized for their many plant health benefits, such as conferring improved growth, disease resistance and abiotic stress tolerance to their hosts. Many Trichoderma species are able to produce the auxin phytohormone indole-3-acetic acid (IAA), and its production has been suggested to promote root growth. Here we show that the production of IAA is strain dependent and diverse external stimuli are associated with its production. In in vitro assays, Arabidopsis primary root length was negatively affected by the interaction with some Trichoderma strains. In soil experiments, a continuum effect on plant growth was shown and this was also strain dependent. In plate assays, some strains of Trichoderma spp. inhibited the expression of the auxin reporter gene DR5 in Arabidopsis primary roots but not secondary roots. When Trichoderma spp. and A. thaliana were physically separated, enhancement of both shoot and root biomass, increased root production and chlorophyll content were observed, which strongly suggested that volatile production by the fungus influenced the parameters analyzed. Trichoderma strains T. virens Gv29.8, T. atroviride IMI206040, T. sp. “atroviride B” LU132, and T. asperellum LU1370 were demonstrated to promote plant growth through volatile production. However, contrasting differences were observed with LU1370 which had a negative effect on plant growth in soil but a positive effect in plate assays. Altogether our results suggest that the mechanisms and molecules involved in plant growth promotion by Trichoderma spp. are multivariable and are affected by the environmental conditions. PMID:28232840

  14. Cortisol, growth hormone, free fatty acids, and experimentally evoked affective arousal.

    PubMed

    Brown, W A; Heninger, G

    1975-11-01

    Eight male volunteers who viewed selected control, suspense, and erotic films experienced significant changes in affect that were limited to fatigue, anxiety, and sexual arousal, respectively. All subjects showed free fatty acid elevations with the suspense and erotic films and those subjects with the most anxiety and sexual arousal showed cortisol elevation with the suspense and erotic films, respectively. Growth hormone elevations occurred independently of cortisol elevations and were not clearly related to film or affect. Thus, activation of the pituitary-adrenocortical and sympathetic nervous systems appears to occur not in relation to a specific dysphoric state but rather with nonspecific affective arousal.

  15. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi.

    PubMed

    Vogels, Chantal B F; Bukhari, Tullu; Koenraadt, Constantianus J M

    2014-06-01

    Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible.

  16. Secondary Work Force Movement into Energy Industry Employment in Areas Affected by "Boom Town" Growth.

    ERIC Educational Resources Information Center

    Jurado, Eugene A.

    A labor market study of implications of rapid energy development in the West examined the dimensions of work force movement from secondary occupations to primary energy occupations in areas affected by "boom town" growth. (Secondary occupations were defined as those in all industries not categorized as primary energy industries.) Focus…

  17. Removal of the local geomagnetic field affects reproductive growth in Arabidopsis.

    PubMed

    Xu, Chunxiao; Wei, Shufeng; Lu, Yan; Zhang, Yuxia; Chen, Chuanfang; Song, Tao

    2013-09-01

    The influence of the geomagnetic field-removed environment on Arabidopsis growth was investigated by cultivation of the plants in a near-null magnetic field and local geomagnetic field (45 µT) for the whole growth period under laboratory conditions. The biomass accumulation of plants in the near-null magnetic field was significantly suppressed at the time when plants were switching from vegetative growth to reproductive growth compared with that of plants grown in the local geomagnetic field, which was caused by a delay in the flowering of plants in the near-null magnetic field. At the early or later growth stage, no significant difference was shown in the biomass accumulation between the plants in the near-null magnetic field and local geomagnetic field. The average number of siliques and the production of seeds per plant in the near-null magnetic field was significantly lower by about 22% and 19%, respectively, than those of control plants. These resulted in a significant reduction of about 20% in the harvest index of plants in the near-null magnetic field compared with that of the controls. These results suggest that the removal of the local geomagnetic field negatively affects the reproductive growth of Arabidopsis, which thus affects the yield and harvest index.

  18. Salinity fluctuation of the brine discharge affects growth and survival of the seagrass Cymodocea nodosa.

    PubMed

    Garrote-Moreno, A; Fernández-Torquemada, Y; Sánchez-Lizaso, J L

    2014-04-15

    The increase of seawater desalination plants may affect seagrasses as a result of its hypersaline effluents. There are some studies on the salinity tolerance of seagrasses under controlled laboratory conditions, but few have been done in situ. To this end, Cymodocea nodosa shoots were placed during one month at four localities: two close to a brine discharge; and the other two not affected by the discharge, and this experiment was repeated four times. The results obtained showed a decrease in growth and an increased mortality at the localities affected by the brine discharge. An increase was detected in the percentage of horizontal shoots in respect to vertical shoots at the impacted localities. It is probably that not only the average salinity, but also the constant salinity fluctuations and slightly higher temperatures associated with the brine that may have caused physiological stress thus reducing C. nodosa growth and survival.

  19. Availability and temporal heterogeneity of water supply affect the vertical distribution and mortality of a belowground herbivore and consequently plant growth.

    PubMed

    Tsunoda, Tomonori; Kachi, Naoki; Suzuki, Jun-Ichirou

    2014-01-01

    We examined how the volume and temporal heterogeneity of water supply changed the vertical distribution and mortality of a belowground herbivore, and consequently affected plant biomass. Plantago lanceolata (Plantaginaceae) seedlings were grown at one per pot under different combinations of water volume (large or small volume) and heterogeneity (homogeneous water conditions, watered every day; heterogeneous conditions, watered every 4 days) in the presence or absence of a larva of the belowground herbivorous insect, Anomala cuprea (Coleoptera: Scarabaeidae). The larva was confined in different vertical distributions to top feeding zone (top treatment), middle feeding zone (middle treatment), or bottom feeding zone (bottom treatment); alternatively no larva was introduced (control treatment) or larval movement was not confined (free treatment). Three-way interaction between water volume, heterogeneity, and the herbivore significantly affected plant biomass. With a large water volume, plant biomass was lower in free treatment than in control treatment regardless of heterogeneity. Plant biomass in free treatment was as low as in top treatment. With a small water volume and in free treatment, plant biomass was low (similar to that under top treatment) under homogeneous water conditions but high under heterogeneous ones (similar to that under middle or bottom treatment). Therefore, there was little effect of belowground herbivory on plant growth under heterogeneous water conditions. In other watering regimes, herbivores would be distributed in the shallow soil and reduced root biomass. Herbivore mortality was high with homogeneous application of a large volume or heterogeneous application of a small water volume. Under the large water volume, plant biomass was high in pots in which the herbivore had died. Thus, the combinations of water volume and heterogeneity affected plant growth via the change of a belowground herbivore.

  20. ‘Peer pressure’ in larval Drosophila?

    PubMed Central

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-01-01

    ABSTRACT Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on ‘peer pressure’, that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila. PMID:24907371

  1. Larval development of the oriental lancelet, Branchiostoma belcheri, in laboratory mass culture.

    PubMed

    Urata, Makoto; Yamaguchi, Nobuo; Henmi, Yasuhisa; Yasui, Kinya

    2007-08-01

    We are successfully maintaining a laboratory colony of the lancelet Branchiostoma belcheri bred in the laboratory. Based on living individuals in this mass culture, morphological characteristics from the seven-day larval to benthic juvenile stages have been studied. Most striking was that later larval development of B. belcheri showed great individual variation even in a rather stable culture environment. Metamorphosis first occurred on 60 days post fertilization (dpf) and was continuously observed throughout the present study up to 100 dpf. Morphological traits such as the number of primary gill slits and body size at the start of metamorphosis are apparently affected by culture condition. Body size measured in the largest individuals showed nearly linear growth at 0.087 mm/day. The variability found in larval development calls for caution when developmental stages and chronological ages are compared between populations. However, the developmental flexibility of this animal also raises the possibility that growth and sexual maturation could be controlled artificially in captivity.

  2. Bean Type Modifies Larval Competition in Zabrotes subfasciatus (Chrysomelidae: Bruchinae).

    PubMed

    Oliveira, S O D; Rodrigues, A S; Vieira, J L; Rosi-Denadai, C A; Guedes, N M P; Guedes, R N C

    2015-08-01

    Larval competition is particularly prevalent among grain beetles that remain within their mother-selected grain throughout development, and the behavioral process of competition is usually inferred by the competition outcome. The Mexican bean weevil Zabrotes subfasciatus (Boheman) is subjected to resource availability variation because of the diversity of common bean types and sizes, from small (e.g., kidney beans) to large (e.g., cranberry beans). The competition process was identified in the Mexican bean weevil reared on kidney and cranberry beans by inference from the competition outcome and by direct observation through digital X-ray imaging. Increased larval density negatively affected adult emergence in kidney beans and reduced adult body mass in both kidney and cranberry beans. Developmental time was faster in cranberry beans. The results allowed for increased larval fitness (i.e., higher larval biomass produced per grain), with larval density reaching a maximum plateau >5 hatched larvae per kidney bean, whereas in cranberry beans, larval fitness linearly increased with density to 13 hatched larvae per bean. These results, together with X-ray imaging without evidence of direct aggressive interaction among larvae, indicate scramble competition, with multiple larvae emerging per grain. However, higher reproductive output was detected for adults from lower density competition with better performance on cranberry beans. Larger populations and fitter adults are expected in intermediate larval densities primarily in cranberry beans where grain losses should be greater.

  3. Fusarium Oxysporum Volatiles Enhance Plant Growth Via Affecting Auxin Transport and Signaling.

    PubMed

    Bitas, Vasileios; McCartney, Nathaniel; Li, Ningxiao; Demers, Jill; Kim, Jung-Eun; Kim, Hye-Seon; Brown, Kathleen M; Kang, Seogchan

    2015-01-01

    Volatile organic compounds (VOCs) have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption.

  4. Fusarium Oxysporum Volatiles Enhance Plant Growth Via Affecting Auxin Transport and Signaling

    PubMed Central

    Bitas, Vasileios; McCartney, Nathaniel; Li, Ningxiao; Demers, Jill; Kim, Jung-Eun; Kim, Hye-Seon; Brown, Kathleen M.; Kang, Seogchan

    2015-01-01

    Volatile organic compounds (VOCs) have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption. PMID:26617587

  5. Modeling the Growth of Archaeon Halobacterium halobium Affected by Temperature and Light.

    PubMed

    Lu, Hao; Yuan, Wenqiao; Cheng, Jay; Rose, Robert B; Classen, John J; Simmons, Otto D

    2017-03-01

    The objective of this study was to develop sigmoidal models, including three-parameter (Quadratic, Logistic, and Gompertz) and four-parameter models (Schnute and Richards) to simulate the growth of archaeon Halobacterium halobium affected by temperature and light. The models were statistically compared by using t test and F test. In the t test, confidence bounds for parameters were used to distinguish among models. For the F test, the lack of fit of the models was compared with the prediction error. The Gompertz model was 100 % accepted by the t test and 97 % accepted by the F test when the temperature effects were considered. Results also indicated that the Gompertz model was 94 % accepted by the F test when the growth of H. halobium was studied under varying light intensities. Thus, the Gompertz model was considered the best among the models studied to describe the growth of H. halobium affected by temperature or light. In addition, the biological growth parameters, including specific growth rate, lag time, and asymptote changes under Gompertz modeling, were evaluated.

  6. Guar meal germ and hull fractions differently affect growth performance and intestinal viscosity of broiler chickens.

    PubMed

    Lee, J T; Bailey, C A; Cartwright, A L

    2003-10-01

    High concentrations of guar meal in poultry diets deleteriously affect growth, feed intake, and digesta viscosity. These effects are attributed to residual gum in the meal. A 2 x 5 factorial experiment investigated the impacts of two guar meal fractions (germ and hull) at five inclusion levels (0, 2.5, 5.0, 7.5, and 10.0%) on intestinal viscosity, measures of growth, and feed conversion in broiler chickens fed to 20 d of age. Growth and feed conversion ratio were not affected by inclusion of as much as 7.5% of the germ fraction into poultry diets, while inclusion of the hull fraction reduced growth at all concentrations. The hull fraction increased intestinal viscosity at all inclusion levels fed, although feed conversion was not affected until the inclusion rate exceeded 5.0%. The germ fraction significantly increased intestinal viscosity at 7.5 and 10% inclusion rates. When germ fraction was fed, relative organ weights remained constant through all concentrations except for the ventriculus and duodenum at 7.5 and 10% inclusion levels. Relative pancreas weight was significantly increased at the 10% level of the hull fraction. Increases in intestinal viscosity corresponded with growth depression. These results suggest that residual gum was responsible for some deleterious effects seen when guar meal was fed. The germ fraction was a superior ingredient when compared with the hull fraction. The guar meal germ fraction constituting as much as 7.5% of the diet supported growth and feed conversion measures similar to those observed with a typical corn-soybean poultry ration.

  7. Alcohol-induced brain growth restrictions (microencephaly) were not affected by concurrent exposure to cocaine during the brain growth spurt.

    PubMed

    Chen, W J; Andersen, K H; West, J R

    1994-09-01

    The prevalence of concomitant use of alcohol and cocaine among drug abusers has raised concern about the possible increased risk of fetal damage. The aim of this study was to assess the interactive effects of alcohol and cocaine on lethality, somatic growth, and brain growth using an animal model system. Sprague-Dawley rat pups were used as subjects. They were randomly assigned to 1 of the 9 artificially reared groups which varied with respect to the combination treatments of cocaine (0, 40, or 60 mg/kg) and alcohol (0, 3.3, or 4.5 g/kg). All artificially reared pups were given daily cocaine and alcohol treatments during a major part of the brain growth spurt period (postnatal days 4-9). An additional group of suckled control animals raised by their natural dams was included to control for artificial rearing. The results are summarized as follows: 1) Drug-induced lethality was higher in cocaine-treated groups when compared with non-cocaine-treated groups, and the concurrent administration of high doses of alcohol and cocaine significantly increased the mortality rate. 2) Somatic growth, in terms of body weight, was not affected by alcohol, cocaine, or the combination of both drugs using the artificial rearing technique. 3) Alcohol exposure during this brain growth spurt period significantly reduced whole brain weight, as well as forebrain, cerebellum, and brain stem weights. 4) In contrast to alcohol, cocaine failed to exert a detrimental effect on brain weight measures during this early postnatal period.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. The microtubule-associated protein MAP18 affects ROP2 GTPase activity during root hair growth.

    PubMed

    Kang, Erfang; Zheng, Mingzhi; Zhang, Yan; Yuan, Ming; Yalovsky, Shaul; Zhu, Lei; Fu, Ying

    2017-03-17

    Establishment and maintenance of the polar site are important for root hair tip growth. We previously reported that Arabidopsis (Arabidopsis thaliana) MICROTUBULE-ASSOCIATED PROTEIN18 (MAP18) functions in controlling the direction of pollen tube growth and root hair elongation. Additionally, the Rop GTPase ROP2 was reported as a positive regulator of both root hair initiation and tip growth in Arabidopsis. Both loss-of-function of ROP2 or knock-down of MAP18 leads to a decrease in root hair length, whereas overexpression of either MAP18 or ROP2 causes multiple tips or a branching hair phenotype. However, it is unclear whether MAP18 and ROP2 coordinately regulate root hair growth. In the present study, we demonstrate that MAP18 and ROP2 interact genetically and functionally. MAP18 physically interacts with ROP2 in vitro and in vivo and preferentially binds to the inactive form of the ROP2 protein. MAP18 promotes ROP2 activity during root hair tip growth. Further investigation revealed that MAP18 competes with RhoGTPase GDP dissociation inhibitor 1 (AtRhoGDI1)/SUPERCENTIPEDE1 (SCN1) for binding to ROP2, in turn affecting localization of active ROP2 in the plasma membrane of the root hair tip. These results reveal a novel function of MAP18 in the regulation of ROP2 activation during root hair growth.

  9. Insulin-like growth factor- I and factors affecting it in thalassemia major.

    PubMed

    Soliman, Ashraf T; De Sanctis, Vincenzo; Elalaily, Rania; Yassin, Mohamed

    2015-01-01

    Despite improvement of blood transfusion regimens and iron chelation therapy growth and maturational delay, cardiomyopathy, endocrinopathies and osteoporosis still occur in good number of thalassemic patients. Decreased IGF-1 secretion occurs in the majority of the thalassemic patients particularly those with growth and pubertal delay. Many factors contribute to this decreased synthesis of IGF-I including disturbed growth hormone (GH) - insulin-like growth factor - I (IGF-I) axis. The possible factors contributing to low IGF-I synthesis in thalassemia and the possible interaction between low IGF-I secretion and the occurrence of these complications is discussed in this mini-review. Improvement of IGF-I secretion in thalassemic patients should be intended to improve linear growth and bone mineral accretion in thalassemic patients. This can be attained through adequate correction of anemia and proper chelation, nutritional supplementation (increasing caloric intake), correction of vitamin D and zinc deficiencies, induction of puberty and correction of hypogonadism at the proper time and treating GH deficiency. This review paper provides a summary of the current state of knowledge regarding IGF-I and factors affecting it in patients with thalassaemia major (TM). Search on PubMed and reference lists of articles with the term 'IGF-I, GH, growth, thalassemia, thyroxine, anemia, vitamin D, and zinc' was carried out. A hundred and forty-eight articles were found and used in the write up and the data analyzed was included in this report.

  10. Pleiotropic Genes Affecting Carcass Traits in Bos indicus (Nellore) Cattle Are Modulators of Growth

    PubMed Central

    Milanesi, Marco; Torrecilha, Rafaela B. P.; Carmo, Adriana S.; Neves, Haroldo H. R.; Carvalheiro, Roberto; Ajmone-Marsan, Paolo; Sonstegard, Tad S.; Sölkner, Johann; Contreras-Castillo, Carmen J.; Garcia, José F.

    2016-01-01

    Two complementary methods, namely Multi-Trait Meta-Analysis and Versatile Gene-Based Test for Genome-wide Association Studies (VEGAS), were used to identify putative pleiotropic genes affecting carcass traits in Bos indicus (Nellore) cattle. The genotypic data comprised over 777,000 single-nucleotide polymorphism markers scored in 995 bulls, and the phenotypic data included deregressed breeding values (dEBV) for weight measurements at birth, weaning and yearling, as well visual scores taken at weaning and yearling for carcass finishing precocity, conformation and muscling. Both analyses pointed to the pleomorphic adenoma gene 1 (PLAG1) as a major pleiotropic gene. VEGAS analysis revealed 224 additional candidates. From these, 57 participated, together with PLAG1, in a network involved in the modulation of the function and expression of IGF1 (insulin like growth factor 1), IGF2 (insulin like growth factor 2), GH1 (growth hormone 1), IGF1R (insulin like growth factor 1 receptor) and GHR (growth hormone receptor), suggesting that those pleiotropic genes operate as satellite regulators of the growth pathway. PMID:27410030

  11. Pleiotropic Genes Affecting Carcass Traits in Bos indicus (Nellore) Cattle Are Modulators of Growth.

    PubMed

    G T Pereira, Anirene; Utsunomiya, Yuri T; Milanesi, Marco; Torrecilha, Rafaela B P; Carmo, Adriana S; Neves, Haroldo H R; Carvalheiro, Roberto; Ajmone-Marsan, Paolo; Sonstegard, Tad S; Sölkner, Johann; Contreras-Castillo, Carmen J; Garcia, José F

    2016-01-01

    Two complementary methods, namely Multi-Trait Meta-Analysis and Versatile Gene-Based Test for Genome-wide Association Studies (VEGAS), were used to identify putative pleiotropic genes affecting carcass traits in Bos indicus (Nellore) cattle. The genotypic data comprised over 777,000 single-nucleotide polymorphism markers scored in 995 bulls, and the phenotypic data included deregressed breeding values (dEBV) for weight measurements at birth, weaning and yearling, as well visual scores taken at weaning and yearling for carcass finishing precocity, conformation and muscling. Both analyses pointed to the pleomorphic adenoma gene 1 (PLAG1) as a major pleiotropic gene. VEGAS analysis revealed 224 additional candidates. From these, 57 participated, together with PLAG1, in a network involved in the modulation of the function and expression of IGF1 (insulin like growth factor 1), IGF2 (insulin like growth factor 2), GH1 (growth hormone 1), IGF1R (insulin like growth factor 1 receptor) and GHR (growth hormone receptor), suggesting that those pleiotropic genes operate as satellite regulators of the growth pathway.

  12. Exploring posttraumatic growth in Tamil children affected by the Indian Ocean Tsunami in 2004.

    PubMed

    Exenberger, Silvia; Ramalingam, Panch; Höfer, Stefan

    2016-10-13

    Few studies explore posttraumatic growth (PTG) in children from Eastern cultures. To help address this gap, the present study examined PTG among 177 South Indian children aged 8-17 years who were affected by the 2004 Tsunami. The study identifies the underlying factor structure of the Tamil version of the Revised Posttraumatic Growth Inventory for Children (PTGI-C-R), and aims to explore the prevalence of PTG, the relationship between distress and growth, and gender and age differences in PTG. The results of the principal component analysis indicated a two-factor structure with an interpersonal and a person-centred dimension of growth. The total scores of the Tamil PTGI-C-R were positively associated with posttraumatic stress symptoms (PTSS) and age. Moreover, there was a significant relationship between age and the person-centred growth subscale. Non-parametric tests found no gender differences in perceived growth. The role of socio-cultural factors on the nature of PTG is discussed.

  13. Macronutrient content of plant-based food affects growth of a carnivorous arthropod.

    PubMed

    Wilder, Shawn M; Holway, David A; Suarez, Andrew V; Eubanks, Micky D

    2011-02-01

    Many arthropods engage in mutualisms in which they consume plant-based foods including nectar, extrafloral nectar, and honeydew. However, relatively little is known about the manner in which the specific macronutrients in these plant-based resources affect growth, especially for carnivorous arthropods. Using a combination of laboratory and field experiments, we tested (1) how plant-based foods, together with ad libitum insect prey, affect the growth of a carnivorous ant, Solenopsis invicta, and (2) which macronutrients in these resources (i.e., carbohydrates, amino acids, or both) contribute to higher colony growth. Access to honeydew increased the production of workers and brood in experimental colonies. This growth effect appeared to be due to carbohydrates alone as colonies provided with the carbohydrate component of artificial extrafloral nectar had greater worker and brood production compared to colonies deprived of carbohydrates. Surprisingly, amino acids only had a slight interactive effect on the proportion of a colony composed of brood and negatively affected worker survival. Diet choice in the laboratory and field matched performance in the laboratory with high recruitment to carbohydrate baits and only slight recruitment to amino acids. The strong, positive effects of carbohydrates on colony growth and the low cost of producing this macronutrient for plants and hemipterans may have aided the evolution of food-for-protection mutualisms and help explain why these interactions are so common in ants. In addition, greater access to plant-based resources in the introduced range of S. invicta may help to explain the high densities achieved by this species throughout the southeastern United States.

  14. Growth of larval agrilus planipennis (Coleoptera: Buprestidae) and fitness of tetrastichus planipennisi (Hymenoptera: Eulophidae) in blue ash (Fraxinus quadrangulata) and green ash (F. pennsylvanica)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emerald ash borer (EAB) (Agrilus planipennis) is a primary pest of North American ash (Fraxinus spp.) trees. Blue ash (F. quadrangulata) is more resistant than other North American ash and able to survive EAB infestation. This tree may affect EAB larvae and T. planipennisi. We compared the capacity ...

  15. Soil particle heterogeneity affects the growth of a rhizomatous wetland plant.

    PubMed

    Huang, Lin; Dong, Bi-Cheng; Xue, Wei; Peng, Yi-Ke; Zhang, Ming-Xiang; Yu, Fei-Hai

    2013-01-01

    Soil is commonly composed of particles of different sizes, and soil particle size may greatly affect the growth of plants because it affects soil physical and chemical properties. However, no study has tested the effects of soil particle heterogeneity on the growth of clonal plants. We conducted a greenhouse experiment in which individual ramets of the wetland plant Bolboschoenus planiculmis were grown in three homogeneous soil treatments with uniformly sized quartz particles (small: 0.75 mm, medium: 1.5 mm, or large: 3 mm), one homogeneous treatment with an even mixture of large and medium particles, and two heterogeneous treatments consisting of 16 or 4 patches of large and medium particles. Biomass, ramet number, rhizome length and spacer length were significantly greater in the treatment with only medium particles than in the one with only large particles. Biomass, ramet number, rhizome length and tuber number in the patchy treatments were greater in patches of medium than of large particles; this difference was more pronounced when patches were small than when they were large. Soil particle size and soil particle heterogeneity can greatly affect the growth of clonal plants. Thus, studies to test the effects of soil heterogeneity on clonal plants should distinguish the effects of nutrient heterogeneity from those of particle heterogeneity.

  16. Metal/metalloid fixation by litter during decomposition affected by silicon availability during plant growth.

    PubMed

    Schaller, Jörg

    2013-03-01

    Organic matter is known to accumulate high amounts of metals/metalloids, enhanced during the process of decomposition by heterotrophic biofilms (with high fixation capacity for metals/metalloids). The colonization by microbes and the decay rate of the organic matter depends on different litter properties. Main litter properties affecting the decomposition of organic matter such as the nutrient ratios and the content of cellulose, lignin and phenols are currently described to be changed by silicon availability. But less is known about the impact of silicon availability during plant growth on elemental fixation during decay. Hence, this research focuses on the impact of silicon availability during plant growth on fixation of 42 elements during litter decay, by controlling the litter properties. The results of this experiment are a significantly higher metal/metalloid accumulation during decomposition of plant litter grown under low silicon availability. This may be explained by the altered litter properties (mainly nutrient content) affecting the microbial decomposition of the litter, the microbial growth on the litter and possibly by the silicon double layer, which is evident in leaf litter with high silicon content and reduces the binding sites for metals/metalloids. Furthermore, this silicon double layer may also reduce the growing biofilm by reducing the availability of carbon compounds at the litter surface and has to be elucidated in further research. Hence, low silicon availability during plant growth enhances the metal/metalloid accumulation into plant litter during aquatic decomposition.

  17. Evolution of increased larval competitive ability in Drosophila melanogaster without increased larval feeding rate.

    PubMed

    Sarangi, Manaswini; Nagarajan, Archana; Dey, Snigdhadip; Bose, Joy; Joshi, Amitabh

    2016-09-01

    Multiple experimental evolution studies on Drosophila melanogaster in the 1980s and 1990s indicated that enhanced competitive ability evolved primarily through increased larval tolerance to nitrogenous wastes and increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and this became the widely accepted view of how adaptation to larval crowding evolves in fruitflies.We recently showed that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolved greater competitive ability without evolving higher feeding rates, primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater efficiency of food conversion to biomass, increased pupation height and, perhaps, greater urea/ammonia tolerance. This was a very different suite of traits than that seen to evolve under similar selection in D. melanogaster and was closer to the expectations from the theory of K-selection. At that time, we suggested two possible reasons for the differences in the phenotypic correlates of greater competitive ability seen in the studies with D. melanogaster and the other two species. First, that D. ananassae and D. n. nasuta had a very different genetic architecture of traits affecting competitive ability compared to the long-term laboratory populations of D. melanogaster used in the earlier studies, either because the populations of the former two species were relatively recently wild-caught, or by virtue of being different species. Second, that the different evolutionary trajectories in D. ananassae and D. n. nasuta versus D. melanogaster were a reflection of differences in the manner in which larval crowding was imposed in the two sets of selection experiments. The D. melanogaster studies used a higher absolute density of eggs per unit volume of food, and a substantially larger total volume of food, than the studies on D. ananassae and D. n. nasuta. Here, we

  18. Gonadotropin ratio affects the in vitro growth of rhesus ovarian preantral follicles

    PubMed Central

    Kim, Yoon Young; Yun, Jun-Won; Kim, Jong Min; Park, Chung Gyu; Rosenwaks, Zev; Liu, Hung Ching; Kang, Byeong-Cheol; Ku, Seung-Yup

    2016-01-01

    In vitro follicle growth (IVFG) strategy is critical in the fertility preservation of cancer survivors; however, its optimal protocol needs to be developed using primate models since the availability of human samples is limited. Only a few previous studies have reported the successful IVFG of rhesus monkey ovaries using low-dose follicle-stimulating hormone (FSH) (0.3 or 3 ng/mL) and long-term culture (up to 5 weeks) and it is still uncertain in regard to the optimal culture duration and effective dose of treated gonadotropins applicable to the IVFG of rhesus preantral follicles. Recently, we have reported that the FSH to luteinizing hormone (LH) ratio affects the in vitro growth of murine ovarian follicles. We aimed to investigate whether gonadotropin ratios affect the efficiency of rhesus follicular growth in vitro. Ovaries were collected from six necropsied rhesus macaques (4–9 years) and preantral follicles were retrieved and cultured for 14 days using 200 mIU/mL FSH. The characteristics of follicular growth were compared between the FSH:LH=1:1 (n=24) and FSH:LH=2:1 (n=24) groups. High concentration gonadotropin treatment shortened the duration required for in vitro maturation of rhesus preantral follicles. The FSH:LH=2:1 group showed a faster follicular growth and enabled the acquisition of mature oocytes, although the expression of growth differentiation factor (GDF)-9 and anti-Müllerian hormone (AMH) did not differ significantly between the two groups. Taken together, high dose gonadotropin treatment can shorten the duration of IVFG and the gonadotropin ratio is important in the IVFG of rhesus monkey ovaries. PMID:26980777

  19. Evolution of increased adult longevity in Drosophila melanogaster populations selected for adaptation to larval crowding.

    PubMed

    Shenoi, V N; Ali, S Z; Prasad, N G

    2016-02-01

    In holometabolous animals such as Drosophila melanogaster, larval crowding can affect a wide range of larval and adult traits. Adults emerging from high larval density cultures have smaller body size and increased mean life span compared to flies emerging from low larval density cultures. Therefore, adaptation to larval crowding could potentially affect adult longevity as a correlated response. We addressed this issue by studying a set of large, outbred populations of D. melanogaster, experimentally evolved for adaptation to larval crowding for 83 generations. We assayed longevity of adult flies from both selected (MCUs) and control populations (MBs) after growing them at different larval densities. We found that MCUs have evolved increased mean longevity compared to MBs at all larval densities. The interaction between selection regime and larval density was not significant, indicating that the density dependence of mean longevity had not evolved in the MCU populations. The increase in longevity in MCUs can be partially attributed to their lower rates of ageing. It is also noteworthy that reaction norm of dry body weight, a trait probably under direct selection in our populations, has indeed evolved in MCU populations. To the best of our knowledge, this is the first report of the evolution of adult longevity as a correlated response of adaptation to larval crowding.

  20. Growth conditions affect carotenoid-based plumage coloration of great tit nestlings

    NASA Astrophysics Data System (ADS)

    Hõrak, P.; Vellau, Helen; Ots, Indrek; Møller, Anders Pape

    Carotenoid-based integument colour in animals has been hypothesised to signal individual phenotypic quality because it reliably reflects either foraging efficiency or health status. We investigated whether carotenoid-derived yellow plumage coloration of fledgling great tits (Parus major) reflects their nestling history. Great tit fledglings reared in a poor year (1998) or in the urban habitat were less yellow than these reared in a good year (1999) or in the forest. The origin of nestlings also affected their coloration since nestlings from a city population did not improve their coloration when transferred to the forest. Brood size manipulation affected fledgling colour, but only in the rural population, where nestlings from reduced broods developed more yellow coloration than nestlings from increased and control broods. Effect of brood size manipulation on fledgling plumage colour was independent of the body mass, indicating that growth environment affects fledgling body mass and plumage colour by different pathways.

  1. InxGa1-xP Nanowire Growth Dynamics Strongly Affected by Doping Using Diethylzinc.

    PubMed

    Otnes, Gaute; Heurlin, Magnus; Zeng, Xulu; Borgström, Magnus T

    2017-02-08

    Semiconductor nanowires are versatile building blocks for optoelectronic devices, in part because nanowires offer an increased freedom in material design due to relaxed constraints on lattice matching during the epitaxial growth. This enables the growth of ternary alloy nanowires in which the bandgap is tunable over a large energy range, desirable for optoelectronic devices. However, little is known about the effects of doping in the ternary nanowire materials, a prerequisite for applications. Here we present a study of p-doping of InxGa1-xP nanowires and show that the growth dynamics are strongly affected when diethylzinc is used as a dopant precursor. Specifically, using in situ optical reflectometry and high-resolution transmission electron microscopy we show that the doping results in a smaller nanowire diameter, a more predominant zincblende crystal structure, a more Ga-rich composition, and an increased axial growth rate. We attribute these effects to changes in seed particle wetting angle and increased TMGa pyrolysis efficiency upon introducing diethylzinc. Lastly, we demonstrate degenerate p-doping levels in InxGa1-xP nanowires by the realization of an Esaki tunnel diode. Our findings provide insights into the growth dynamics of ternary alloy nanowires during doping, thus potentially enabling the realization of such nanowires with high compositional homogeneity and controlled doping for high-performance optoelectronics devices.

  2. Shoot Turgor Does Not Limit Shoot Growth of NaCl-Affected Wheat and Barley 1

    PubMed Central

    Termaat, Annie; Passioura, John B.; Munns, Rana

    1985-01-01

    The aim of this work was to test the hypothesis that the reduced growth rate of wheat and barley that results when the roots are exposed to NaCl is due to inadequate turgor in the expanding cells of the leaves. The hypothesis was tested by exposing plants to 100 millimolar NaCl (which reduced their growth rates by about 20%), growing them for 7 to 10 days with their roots in pressure chambers, and applying sufficient pneumatic pressure in the chambers to offset the osmotic pressure of the NaCl, namely, 0.48 megapascals. The results showed that applying the pressure had no sustained effect (relative to unpressurized controls) on growth rates, transpiration rates, or osmotic pressures of the cell sap, in either the fully expanded or currently expanding leaf tissue, of both wheat and barley. The results indicate that the applied pressure correspondingly increased turgor in the shoot although this was not directly measured. We conclude that shoot turgor alone was not regulating the growth of these NaCl-affected plants, and, after discussing other possible influences, argue that a message arising in the roots may be regulating the growth of the shoot. PMID:16664152

  3. Root cooling strongly affects diel leaf growth dynamics, water and carbohydrate relations in Ricinus communis.

    PubMed

    Poiré, Richard; Schneider, Heike; Thorpe, Michael R; Kuhn, Arnd J; Schurr, Ulrich; Walter, Achim

    2010-03-01

    In laboratory and greenhouse experiments with potted plants, shoots and roots are exposed to temperature regimes throughout a 24 h (diel) cycle that can differ strongly from the regime under which these plants have evolved. In the field, roots are often exposed to lower temperatures than shoots. When the root-zone temperature in Ricinus communis was decreased below a threshold value, leaf growth occurred preferentially at night and was strongly inhibited during the day. Overall, leaf expansion, shoot biomass growth, root elongation and ramification decreased rapidly, carbon fluxes from shoot to root were diminished and carbohydrate contents of both root and shoot increased. Further, transpiration rate was not affected, yet hydrostatic tensions in shoot xylem increased. When root temperature was increased again, xylem tension reduced, leaf growth recovered rapidly, carbon fluxes from shoot to root increased, and carbohydrate pools were depleted. We hypothesize that the decreased uptake of water in cool roots diminishes the growth potential of the entire plant - especially diurnally, when the growing leaf loses water via transpiration. As a consequence, leaf growth and metabolite concentrations can vary enormously, depending on root-zone temperature and its heterogeneity inside pots.

  4. Hypoxia tolerance of common sole juveniles depends on dietary regime and temperature at the larval stage: evidence for environmental conditioning.

    PubMed

    Zambonino-Infante, José L; Claireaux, Guy; Ernande, Bruno; Jolivet, Aurélie; Quazuguel, Patrick; Sévère, Armelle; Huelvan, Christine; Mazurais, David

    2013-05-07

    An individual's environmental history may have delayed effects on its physiology and life history at later stages in life because of irreversible plastic responses of early ontogenesis to environmental conditions. We chose a marine fish, the common sole, as a model species to study these effects, because it inhabits shallow marine areas highly exposed to environmental changes. We tested whether temperature and trophic conditions experienced during the larval stage had delayed effects on life-history traits and resistance to hypoxia at the juvenile stage. We thus examined the combined effect of global warming and hypoxia in coastal waters, which are potential stressors to many estuarine and coastal marine fishes. Elevated temperature and better trophic conditions had a positive effect on larval growth and developmental rates; warmer larval temperature had a delayed positive effect on body mass and resistance to hypoxia at the juvenile stage. The latter suggests a lower oxygen demand of individuals that had experienced elevated temperatures during larval stages. We hypothesize that an irreversible plastic response to temperature occurred during early ontogeny that allowed adaptive regulation of metabolic rates and/or oxygen demand with long-lasting effects. These results could deeply affect predictions about impacts of global warming and eutrophication on marine organisms.

  5. Suspended sediment prolongs larval development in a coral reef fish.

    PubMed

    Wenger, Amelia S; McCormick, Mark I; Endo, Geoffrey G K; McLeod, Ian M; Kroon, Frederieke J; Jones, Geoffrey P

    2014-04-01

    Increasing sediment input into coastal environments is having a profound influence on shallow marine habitats and associated species. Coral reef ecosystems appear to be particularly sensitive, with increased sediment deposition and re-suspension being associated with declines in the abundance and diversity of coral reef fishes. While recent research has demonstrated that suspended sediment can have negative impacts on post-settlement coral reef fishes, its effect on larval development has not been investigated. In this study, we tested the effects of different levels of suspended sediment on larval growth and development time in Amphiprion percula, a coral reef damselfish. Larvae were subjected to four experimental concentrations of suspended sediment spanning the range found around coastal coral reefs (0-45 mg l(-1)). Larval duration was significantly longer in all sediment treatments (12 days) compared with the average larval duration in the control treatment (11 days). Approximately 75% of the fish in the control had settled by day 11, compared with only 40-46% among the sediment treatments. In the highest sediment treatment, some individuals had a larval duration twice that of the median duration in the control treatment. Unexpectedly, in the low sediment treatment, fish at settlement were significantly longer and heavier compared with fish in the other treatments, suggesting delayed development was independent of individual condition. A sediment-induced extension of the pelagic larval stage could significantly reduce numbers of larvae competent to settle and, in turn, have major effects on adult population dynamics.

  6. Spatial heterogeneity of soil biochar content affects soil quality and wheat growth and yield.

    PubMed

    Olmo, Manuel; Lozano, Ana María; Barrón, Vidal; Villar, Rafael

    2016-08-15

    Biochar (BC) is a carbonaceous material obtained by pyrolysis of organic waste materials and has been proposed as a soil management strategy to mitigate global warming and to improve crop productivity. Once BC has been applied to the soil, its imperfect and incomplete mixing with soil during the first few years and the standard agronomic practices (i.e. tillage, sowing) may generate spatial heterogeneity of the BC content in the soil, which may have implications for soil properties and their effects on plant growth. We investigated how, after two agronomic seasons, the spatial heterogeneity of olive-tree prunings BC applied to a vertisol affected soil characteristics and wheat growth and yield. During the second agronomic season and just before wheat germination, we determined the BC content in the soil by an in-situ visual categorization based on the soil darkening, which was strongly correlated to the BC content of the soil and the soil brightness. We found a high spatial heterogeneity in the BC plots, which affected soil characteristics and wheat growth and yield. Patches with high BC content showed reduced soil compaction and increased soil moisture, pH, electrical conductivity, and nutrient availability (P, Ca, K, Mn, Fe, and Zn); consequently, wheat had greater tillering and higher relative growth rate and grain yield. However, if the spatial heterogeneity of the soil BC content had not been taken into account in the data analysis, most of the effects of BC on wheat growth would not have been detected. Our study reveals the importance of taking into account the spatial heterogeneity of the BC content.

  7. Crack growth rates of irradiated austenitic stainless steel weld heat affected zone in BWR environments.

    SciTech Connect

    Chopra, O. K.; Alexandreanu, B.; Gruber, E. E.; Daum, R. S.; Shack, W. J.; Energy Technology

    2006-01-31

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of reactor pressure vessels because of their superior fracture toughness. However, exposure to high levels of neutron irradiation for extended periods can exacerbate the corrosion fatigue and stress corrosion cracking (SCC) behavior of these steels by affecting the material microchemistry, material microstructure, and water chemistry. Experimental data are presented on crack growth rates of the heat affected zone (HAZ) in Types 304L and 304 SS weld specimens before and after they were irradiated to a fluence of 5.0 x 10{sup 20} n/cm{sup 2} (E > 1 MeV) ({approx} 0.75 dpa) at {approx}288 C. Crack growth tests were conducted under cycling loading and long hold time trapezoidal loading in simulated boiling water reactor environments on Type 304L SS HAZ of the H5 weld from the Grand Gulf reactor core shroud and on Type 304 SS HAZ of a laboratory-prepared weld. The effects of material composition, irradiation, and water chemistry on growth rates are discussed.

  8. Genetic mapping of quantitative trait loci affecting growth and carcass traits in F2 intercross chickens.

    PubMed

    Uemoto, Y; Sato, S; Odawara, S; Nokata, H; Oyamada, Y; Taguchi, Y; Yanai, S; Sasaki, O; Takahashi, H; Nirasawa, K; Kobayashi, E

    2009-03-01

    We constructed a chicken F(2) resource population to facilitate the genetic improvement of economically important traits, particularly growth and carcass traits. An F(2) population comprising 240 chickens obtained by crossing a Shamo (lean, lightweight Japanese native breed) male and White Plymouth Rock breed (fat, heavyweight broiler) females was measured for BW, carcass weight (CW), abdominal fat weight (AFW), breast muscle weight (BMW), and thigh muscle weight (TMW) and was used for genome-wide linkage and QTL analysis, using a total of 240 microsatellite markers. A total of 14 QTL were detected at a 5% chromosome-wide level, and 7 QTL were significant at a 5% experiment-wide level for the traits evaluated in the F(2) population. For growth traits, significant and suggestive QTL affecting BW (measured at 6 and 9 wk) and average daily gain were identified on similar regions of chromosomes 1 and 3. For carcass traits, the QTL effects on CW were detected on chromosomes 1 and 3, with the greatest F-ratio of 15.0 being obtained for CW on chromosome 3. Quantitative trait loci positions affecting BMW and TMW were not detected at the same loci as those detected for BMW percentage of CW and TMW percentage of CW. For AFW, QTL positions were detected at the same loci as those detected for AFW percentage of CW. The present study identified significant QTL affecting BW, CW, and AFW.

  9. Response to long-term growth hormone therapy in patients affected by RASopathies and growth hormone deficiency: Patterns of growth, puberty and final height data.

    PubMed

    Tamburrino, Federica; Gibertoni, Dino; Rossi, Cesare; Scarano, Emanuela; Perri, Annamaria; Montanari, Francesca; Fantini, Maria Pia; Pession, Andrea; Tartaglia, Marco; Mazzanti, Laura

    2015-11-01

    RASopathies are developmental disorders caused by heterozygous germline mutations in genes encoding proteins in the RAS-MAPK signaling pathway. Reduced growth is a common feature. Several studies generated data on growth, final height (FH), and height velocity (HV) after growth hormone (GH) treatment in patients with these disorders, particularly in Noonan syndrome, the most common RASopathy. These studies, however, refer to heterogeneous cohorts in terms of molecular information, GH status, age at start and length of therapy, and GH dosage. This work reports growth data in 88 patients affected by RASopathies with molecularly confirmed diagnosis, together with statistics on body proportions, pubertal pattern, and FH in 33, including 16 treated with GH therapy for proven GH deficiency. Thirty-three patients showed GH deficiency after pharmacological tests, and were GH-treated for an average period of 6.8 ± 4.8 years. Before starting therapy, HV was -2.6 ± 1.3 SDS, and mean basal IGF1 levels were -2.0 ± 1.1 SDS. Long-term GH therapy, starting early during childhood, resulted in a positive height response compared with untreated patients (1.3 SDS in terms of height-gain), normalizing FH for Ranke standards but not for general population and Target Height. Pubertal timing negatively affected pubertal growth spurt and FH, with IGF1 standardized score increased from -2.43 to -0.27 SDS. During GH treatment, no significant change in bone age velocity, body proportions, or cardiovascular function was observed.

  10. Chronic playback of boat noise does not impact hatching success or post-hatching larval growth and survival in a cichlid fish

    PubMed Central

    Radford, Andrew N.

    2014-01-01

    Anthropogenic (man-made) noise has been shown to have a negative impact on the behaviour and physiology of a range of terrestrial and aquatic animals. However, direct assessments of fitness consequences are rare. Here we examine the effect of additional noise on early life stages in the model cichlid fish, Neolamprologus pulcher. Many fishes use and produce sounds, they are crucial elements of aquatic ecosystems, and there is mounting evidence that they are vulnerable to anthropogenic noise; adult N. pulcher have recently been shown to change key behaviours during playback of motor boat noise. Using a split-brood design to eliminate potential genetic effects, we exposed half of the eggs and fry from each clutch to four weeks of playbacks of noise originally recorded from small motor boats with the other half acting as a control (receiving no noise playback). There was no significant effect of additional noise on hatching success or fry survival, length or weight at the end of the exposure period. Although care should be taken not to generalize these findings on a single species from a laboratory study, our data suggest that moderate noise increases do not necessarily have direct negative impacts on early-life survival and growth. Further studies on a range of species in natural conditions are urgently needed to inform conservation efforts and policy decisions about the consequences of anthropogenic noise. PMID:25276507

  11. Opioid and nicotine receptors affect growth regulation of human lung cancer cell lines

    SciTech Connect

    Maneckjee, R.; Minna, J.D. Uniformed Services Univ. of the Health Sciences, Bethesda, MD )

    1990-05-01

    Using specific radioactively-labeled ligands, the authors find that lung cancer cell lines of diverse histologic types express multiple, high-affinity membrane receptors for {mu}, {delta}, and {kappa} opioid agonists and for nicotine and {alpha}-bungarotoxin. These receptors are biologically active because cAMP levels decreased in lung cancer cells after opioid and nicotine application. Nicotine at concentrations found in the blood of smokers had no effect on in vitro lung cancer cell growth, whereas {mu}, {delta}, and {kappa} opioid agonists at low concentrations inhibited lung cancer growth in vitro. They also found that lung cancer cells expressed various combinations of immunoreactive opioid peptides ({beta}-endorphin, enkephalin, or dynorphin), suggesting the participation of opioids in a negative autocrine loop or tumor-suppressing system. Due to the almost universal exposure of patients with lung cancer to nicotine, they tested whether nicotine affected the response of lung cancer cell growth to opioids and found that nicotine at concentrations of 100-200 nM partially or totally reversed opioid-induced growth inhibition in 9/14 lung cancer cell lines. These in vitro results for lung cancer cells suggest that opioids could function as part of a tumor suppressor system and that nicotine can function to circumvent this system in the pathogenesis of lung cancer.

  12. Alkyl-methylimidazolium ionic liquids affect the growth and fermentative metabolism of Clostridium sp

    SciTech Connect

    Nancharaiah, Y.V.; Francis, A.

    2011-06-01

    In this study, the effect of ionic liquids, 1-ethyl-3-methylimidazolium acetate [EMIM][Ac], 1-ethyl-3-methylimidazolium diethylphosphate [EMIM][DEP], and 1-methyl-3-methylimidazolium dimethylphosphate [MMIM][DMP] on the growth and glucose fermentation of Clostridium sp. was investigated. Among the three ionic liquids tested, [MMIM][DMP] was found to be least toxic. Growth of Clostridium sp. was not inhibited up to 2.5, 4 and 4 g L{sup -1} of [EMIM][Ac], [EMIM][DEP] and [MMIM][DMP], respectively. [EMIM][Ac] at <2.5 g L{sup -1}, showed hormetic effect and stimulated the growth and fermentation by modulating medium pH. Total organic acid production increased in the presence of 2.5 and 2 g L{sup -1} of [EMIM][Ac] and [MMIM][DMP]. Ionic liquids had no significant influence on alcohol production at <2.5 g L{sup -1}. Total gas production was affected by ILs at {ge}2.5 g L{sup -1} and varied with type of methylimidazolium IL. Overall, the results show that the growth and fermentative metabolism of Clostridium sp. is not impacted by ILs at concentrations below 2.5 g L{sup -1}.

  13. Long-term cleaner fish presence affects growth of a coral reef fish

    PubMed Central

    Clague, Gillian E.; Cheney, Karen L.; Goldizen, Anne W.; McCormick, Mark I.; Waldie, Peter A.; Grutter, Alexandra S.

    2011-01-01

    Cleaning behaviour is considered to be a classical example of mutualism. However, no studies, to our knowledge, have measured the benefits to clients in terms of growth. In the longest experimental study of its kind, over an 8 year period, cleaner fish Labroides dimidiatus were consistently removed from seven patch reefs (61–285 m2) and left undisturbed on nine control reefs, and the growth and parasite load of the damselfish Pomacentrus moluccensis determined. After 8 years, growth was reduced and parasitic copepod abundance was higher on fish from removal reefs compared with controls, but only in larger individuals. Behavioural observations revealed that P. moluccensis cleaned by L. dimidiatus were 27 per cent larger than nearby conspecifics. The selective cleaning by L. dimidiatus probably explains why only larger P. moluccensis individuals benefited from cleaning. This is the first demonstration, to our knowledge, that cleaners affect the growth rate of client individuals; a greater size for a given age should result in increased fecundity at a given time. The effect of the removal of so few small fish on the size of another fish species is unprecedented on coral reefs. PMID:21733872

  14. Exposure to coal combustion residues during metamorphosis elevates corticosterone content and adversely affects oral morphology, growth, and development in Rana sphenocephala

    SciTech Connect

    Peterson, J.D.; Peterson, V.A.; Mendonca, M.T.

    2009-01-15

    Coal combustion residues (CCRs) are documented to negatively impact oral morphology, growth, and development in larval amphibians. It is currently unclear what physiological mechanisms may mediate these effects. Corticosterone, a glucocorticoid hormone, is a likely mediator because when administered exogenously it, like CCRs, also negatively influences oral morphology, growth, and development in larval amphibians. In an attempt to identify if corticosterone mediates these effects, we raised larval Southern Leopard Frogs, Rana sphenocephala, on either sand or CCR substrate and documented effects of sediment type on whole body corticosterone, oral morphology, and time to and mass at key metamorphic stages. Coal combustion residue treated tadpoles contained significantly more corticosterone than controls throughout metamorphosis. However, significantly more oral abnormalities occurred early in metamorphosis when differences in corticosterone levels between treatments were minimal. Overall, CCR-treated tadpoles took significantly more time to transition between key stages and gained less mass between stages than controls, but these differences between treatments decreased during later stages when corticosterone differences between treatments were greatest. Our results suggest endogenous increase in corticosterone content and its influence on oral morphology, growth and development is more complex than previously thought.

  15. ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation.

    PubMed

    Hsueh, Yi-Huang; Ke, Wan-Ju; Hsieh, Chien-Te; Lin, Kuen-Song; Tzou, Dong-Ying; Chiang, Chao-Lung

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm), with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5-10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles.

  16. ZnO Nanoparticles Affect Bacillus subtilis Cell Growth and Biofilm Formation

    PubMed Central

    Hsueh, Yi-Huang; Ke, Wan-Ju; Hsieh, Chien-Te; Lin, Kuen-Song; Tzou, Dong-Ying; Chiang, Chao-Lung

    2015-01-01

    Zinc oxide nanoparticles (ZnO NPs) are an important antimicrobial additive in many industrial applications. However, mass-produced ZnO NPs are ultimately disposed of in the environment, which can threaten soil-dwelling microorganisms that play important roles in biodegradation, nutrient recycling, plant protection, and ecological balance. This study sought to understand how ZnO NPs affect Bacillus subtilis, a plant-beneficial bacterium ubiquitously found in soil. The impact of ZnO NPs on B. subtilis growth, FtsZ ring formation, cytosolic protein activity, and biofilm formation were assessed, and our results show that B. subtilis growth is inhibited by high concentrations of ZnO NPs (≥ 50 ppm), with cells exhibiting a prolonged lag phase and delayed medial FtsZ ring formation. RedoxSensor and Phag-GFP fluorescence data further show that at ZnO-NP concentrations above 50 ppm, B. subtilis reductase activity, membrane stability, and protein expression all decrease. SDS-PAGE Stains-All staining results and FT-IR data further demonstrate that ZnO NPs negatively affect exopolysaccharide production. Moreover, it was found that B. subtilis biofilm surface structures became smooth under ZnO-NP concentrations of only 5–10 ppm, with concentrations ≤ 25 ppm significantly reducing biofilm formation activity. XANES and EXAFS spectra analysis further confirmed the presence of ZnO in co-cultured B. subtilis cells, which suggests penetration of cell membranes by either ZnO NPs or toxic Zn+ ions from ionized ZnO NPs, the latter of which may be deionized to ZnO within bacterial cells. Together, these results demonstrate that ZnO NPs can affect B. subtilis viability through the inhibition of cell growth, cytosolic protein expression, and biofilm formation, and suggest that future ZnO-NP waste management strategies would do well to mitigate the potential environmental impact engendered by the disposal of these nanoparticles. PMID:26039692

  17. Internet: An Overview of Key Technology Policy Issues Affecting Its Use and Growth

    DTIC Science & Technology

    2004-12-29

    Alliance General Types of Internet Services B2B Business-to-Business B2G Business-to-Government G2B Government-to-Business G2C Government-to-Citizen G2G...Congressional Research Service ˜ The Library of Congress CRS Report for Congress Received through the CRS Web Order Code 98-67 STM Internet : An...DATES COVERED - 4. TITLE AND SUBTITLE Internet : An Overview of Key Technology Policy Issues Affecting Its Use and Growth 5a. CONTRACT NUMBER 5b

  18. Two novel herbicide candidates affect Arabidopsis thaliana growth by inhibiting nitrogen and phosphate absorption.

    PubMed

    Sun, Chongchong; Jin, Yujian; He, Haifeng; Wang, Wei; He, Hongwu; Fu, Zhengwei; Qian, Haifeng

    2015-09-01

    Both 2-[(2,4-dichlorophenoxy)acetoxy](methy)lmethyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIa) and 2-[(4-chloro-2-methyl-phenoxy)-acetoxy](methyl)methyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIr) are novel herbicide candidates that positively affect herbicidal activity via the introduction of a phosphorus-containing heterocyclic ring. This report investigated the mechanism of IIa and IIr on weed control in the model plant Arabidopsis thaliana at physiological, ultrastructural and molecular levels. IIa and IIr significantly inhibited the growth of A. thaliana and altered its root structure by inhibiting energy metabolism and lipid or protein biosynthesis. These compounds also significantly affected the absorption of nitrogen and phosphorus by down-regulating the transcripts of nitrate transporter-related genes, ammonium transporter-related genes and phosphorus transporter-related genes.

  19. Essential oils from clove affect growth of Penicillium species obtained from lemons.

    PubMed

    Martínez, J A; González, R

    2013-01-01

    Continuous use of fungicides to control citrus postharvest diseases has led to increasing resistant strains of pathogens. Since the appearance of fungicide resistance has become an important factor in limiting the efficacy fungicide treatments, new studies have been needed in order to improve control methods. There is a growing consumer's concern about the possible harmful effects of synthetic fungicides on the human health and the environment. Alternatives to synthetic fungicides for citrus decay control include essential oils. These compounds are known for their natural components and they are searched for potential bioactive plant extracts against fungi. In this study, two isolates of P. digitatum and P. italicum each were collected from lemon fruits affected by green and blue mould, respectively. Isolates were purified in potato dextrose agar (PDA) in order to separate the two species which we are demonstrated that they commonly grow together in nature. In vitro assays, in which isolates were grown at 26 degrees C on Petri dishes containing PDA for up to 17 days, were carried out by pouring several doses of essential oils from clove (Syzygium aromaticum L.) on PDA to obtain the following concentrations (v/v): 1.6; 8, 40, 200 and 500 microL L(-1) + tween 80 (0.1 mL L(-1)). Mycelial growth curves and growth, conidiation, mass of aerial mycelium and conidial size were measured. Penicillium isolates showed a slight degree of variability in their growth kinetics, depending on the isolate. 500 microL L(-1) inhibited the growth of all the isolates, whereas concentrations lower than 40 microL L(-1) slightly increased the growth. 200 microL L(-1) reduced both growth and conidiation in all isolates. Aerial mycelium of P. digitatum was not affected by clove, whereas reduced the mass of mycelium of P. italicum at concentrations higher than 8 microL L(-1). In vivo experiment was carried out inoculating a drop of an extract of conidia with a hypodermal syringe though a

  20. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  1. Remnant trees affect species composition but not structure of tropical second-growth forest.

    PubMed

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  2. Non-patient related variables affecting levels of vascular endothelial growth factor in urine biospecimens.

    PubMed

    Kirk, M J; Hayward, R M; Sproull, M; Scott, T; Smith, S; Cooley-Zgela, T; Crouse, N S; Citrin, D E; Camphausen, K

    2008-08-01

    Vascular endothelial growth factor (VEGF) is an angiogenic protein proposed to be an important biomarker for the prediction of tumour growth and disease progression. Recent studies suggest that VEGF measurements in biospecimens, including urine, may have predictive value across a range of cancers. However, the reproducibility and reliability of urinary VEGF measurements have not been determined. We collected urine samples from patients receiving radiation treatment for glioblastoma multiforme (GBM) and examined the effects of five variables on measured VEGF levels using an ELISA assay. To quantify the factors affecting the precision of the assay, two variables were examined: the variation between ELISA kits with different lot numbers and the variation between different technicians. Three variables were tested for their effects on measured VEGF concentration: the time the specimen spent at room temperature prior to assay, the addition of protease inhibitors prior to specimen storage and the alteration of urinary pH. This study found that VEGF levels were consistent across three different ELISA kit lot numbers. However, significant variation was observed between results obtained by different technicians. VEGF concentrations were dependent on time at room temperature before measurement, with higher values observed 3-7 hrs after removal from the freezer. No significant difference was observed in VEGF levels with the addition of protease inhibitors, and alteration of urinary pH did not significantly affect VEGF measurements. In conclusion, this determination of the conditions necessary to reliably measure urinary VEGF levels will be useful for future studies related to protein biomarkers and disease progression.

  3. Overexpression of a glutamine synthetase gene affects growth and development in sorghum.

    PubMed

    Urriola, Jazmina; Rathore, Keerti S

    2015-06-01

    Nitrogen is a primary macronutrient in plants, and nitrogen fertilizers play a critical role in crop production and yield. In this study, we investigated the effects of overexpressing a glutamine synthetase (GS) gene on nitrogen metabolism, and plant growth and development in sorghum (Sorghum bicolor L., Moench). GS catalyzes the ATP dependent reaction between ammonia and glutamate to produce glutamine. A 1,071 bp long coding sequence of a sorghum cytosolic GS gene (Gln1) under the control of the maize ubiquitin (Ubq) promoter was introduced into sorghum immature embryos by Agrobacterium-mediated transformation. Progeny of the transformants exhibited higher accumulation of the Gln1 transcripts and up to 2.2-fold higher GS activity compared to the non-transgenic controls. When grown under optimal nitrogen conditions, these Gln1 transgenic lines showed greater tillering and up to 2.1-fold increase in shoot vegetative biomass. Interestingly, even under greenhouse conditions, we observed a seasonal component to both these parameters and the grain yield. Our results, showing that the growth and development of sorghum Gln1 transformants are also affected by N availability and other environmental factors, suggest complexity of the relationship between GS activity and plant growth and development. A better understanding of other control points and the ability to manipulate these will be needed to utilize the transgenic technology to improve nitrogen use efficiency of crop plants.

  4. Waving and skewing: how gravity and the surface of growth media affect root development in Arabidopsis.

    PubMed

    Oliva, Michele; Dunand, Christophe

    2007-01-01

    Arabidopsis seedlings growing on inclined agar surfaces exhibit characteristic root behaviours called 'waving' and 'skewing': the former consists of a series of undulations, whereas the latter is a deviation from the direction of gravity. Even though the precise basis of these growth patterns is not well understood, both gravity and the contact between the medium and the root are considered to be the major players that result in these processes. The influence of these forces on root surface-dependent behaviours can be verified by growing seedlings at different gel pitches: plants growing on vertical plates present roots with slight waving and skewing when compared with seedlings grown on plates held at minor angles of < 90 degrees . However, other factors are thought to modulate root growth on agar; for instance, it has been demonstrated that the presence and concentration of certain compounds in the medium (such as sucrose) and of drugs able to modify the plant cell cytoskeleton also affect skewing and waving. The recent discovery of an active role of ethylene on surface-dependent root behaviour, and the finding of new mutants showing anomalous growth, pave the way for a more detailed description of these phenomena.

  5. Streptomycin affects the growth and photochemical activity of the alga Chlorella vulgaris.

    PubMed

    Perales-Vela, Hugo Virgilio; García, Roberto Velasco; Gómez-Juárez, Evelyn Alicia; Salcedo-Álvarez, Martha Ofelia; Cañizares-Villanueva, Rosa Olivia

    2016-10-01

    Antibiotics are increasingly being used in human and veterinary medicine, as well as pest control in agriculture. Recently, their emergence in the aquatic environment has become a global concern. The aim of this study was to evaluate the effect of streptomycin on growth and photosynthetic activity of Chlorella vulgaris after 72h exposure. We found that growth, photosynthetic activity and the content of the D1 protein of photosystem II decreased. Analysis of chlorophyll a fluorescence emission shows a reduction in the energy transfer between the antenna complex and reaction center. Also the activity of the oxygen evolution complex and electron flow between QA and QB were significantly reduced; in contrast, we found an increase in the reduction rate of the acceptor side of photosystem I. The foregoing can be attributed to the inhibition of the synthesis of the D1 protein and perhaps other coded chloroplast proteins that are part of the electron transport chain which are essential for the transformation of solar energy in the photosystems. We conclude that micromolar concentrations of streptomycin can affect growth and photosynthetic activity of Chlorella vulgaris. The accumulation of antibiotics in the environment can become an ecological problem for primary producers in the aquatic environment.

  6. Salt affects plant Cd-stress responses by modulating growth and Cd accumulation.

    PubMed

    Xu, Jin; Yin, Hengxia; Liu, Xiaojing; Li, Xia

    2010-01-01

    Cadmium contamination is a serious environmental problem for modern agriculture and human health. Salinity affects plant growth and development, and interactions between salt and cadmium have been reported. However, the molecular mechanisms of salinity-cadmium interactions are not fully understood. Here, we show that a low concentration of salt alleviates Cd-induced growth inhibition and increases Cd accumulation in Arabidopsis thaliana. Supplementation with low concentrations of salt reduced the reactive oxygen species level in Cd-stressed roots by increasing the contents of proline and glutathione and down-regulating the expression of RCD1, thereby protecting the plasma membrane integrity of roots under cadmium stress. Salt supplementation substantially reduces the Cd-induced elevation of IAA oxidase activity, thereby maintaining auxin levels in Cd-stressed plants, as indicated by DR5::GUS expression. Salt supply increased Cd absorption in roots and increased Cd accumulation in leaves, implying that salt enhances both Cd uptake in roots and the root-to-shoot translocation of Cd. The elevated Cd accumulation in plants in response to salt was found to be correlated with the elevated levels of phytochelatin the expression of heavy metal transporters AtHMA1-4, especially AtHMA4. Salt alleviated growth inhibition caused by Cd and increased Cd accumulation also was observed in Cd accumulator Solanum nigrum.

  7. L-carnosine affects the growth of Saccharomyces cerevisiae in a metabolism-dependent manner.

    PubMed

    Cartwright, Stephanie P; Bill, Roslyn M; Hipkiss, Alan R

    2012-01-01

    The dipeptide L-carnosine (β-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10-30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types.

  8. PMT family of Candida albicans: five protein mannosyltransferase isoforms affect growth, morphogenesis and antifungal resistance.

    PubMed

    Prill, Stephan K-H; Klinkert, Birgit; Timpel, Claudia; Gale, Cheryl A; Schröppel, Klaus; Ernst, Joachim F

    2005-01-01

    Protein O-mannosyltransferases (Pmt proteins) initiate O-mannosylation of secretory proteins. The PMT gene family of the human fungal pathogen Candida albicans consists of PMT1 and PMT6, as well as three additional PMT genes encoding Pmt2, Pmt4 and Pmt5 isoforms described here. Both PMT2 alleles could not be deleted and growth of conditional strains, containing PMT2 controlled by the MET3- or tetOScHOP1-promoters, was blocked in non-permissive conditions, indicating that PMT2 is essential for growth. A homozygous pmt4 mutant was viable, but synthetic lethality of pmt4 was observed in combination with pmt1 mutations. Hyphal morphogenesis of a pmt4 mutant was defective under aerobic induction conditions, yet increased in embedded or hypoxic conditions, suggesting a role of Pmt4p-mediated O-glycosylation for environment-specific morphogenetic signalling. Although a PMT5 transcript was detected, a homozygous pmt5 mutant was phenotypically silent. All other pmt mutants showed variable degrees of supersensitivity to antifungals and to cell wall-destabilizing agents. Cell wall composition was markedly affected in pmt1 and pmt4 mutants, showing a significant decrease in wall mannoproteins. In a mouse model of haematogenously disseminated infection, PMT4 was required for full virulence of C. albicans. Functional analysis of the first complete PMT gene family in a fungal pathogen indicates that Pmt isoforms have variable and specific roles for in vitro and in vivo growth, morphogenesis and antifungal resistance.

  9. Modest maternal caffeine exposure affects developing embryonic cardiovascular function and growth.

    PubMed

    Momoi, Nobuo; Tinney, Joseph P; Liu, Li J; Elshershari, Huda; Hoffmann, Paul J; Ralphe, John C; Keller, Bradley B; Tobita, Kimimasa

    2008-05-01

    Caffeine consumption during pregnancy is reported to increase the risk of in utero growth restriction and spontaneous abortion. In the present study, we tested the hypothesis that modest maternal caffeine exposure affects in utero developing embryonic cardiovascular (CV) function and growth without altering maternal hemodynamics. Caffeine (10 mg.kg(-1).day(-1) subcutaneous) was administered daily to pregnant CD-1 mice from embryonic days (EDs) 9.5 to 18.5 of a 21-day gestation. We assessed maternal and embryonic CV function at baseline and at peak maternal serum caffeine concentration using high-resolution echocardiography on EDs 9.5, 11.5, 13.5, and 18.5. Maternal caffeine exposure did not influence maternal body weight gain, maternal CV function, or embryo resorption. However, crown-rump length and body weight were reduced in maternal caffeine treated embryos by ED 18.5 (P < 0.05). At peak maternal serum caffeine concentration, embryonic carotid artery, dorsal aorta, and umbilical artery flows transiently decreased from baseline at ED 11.5 (P < 0.05). By ED 13.5, embryonic aortic and umbilical artery flows were insensitive to the peak maternal caffeine concentration; however, the carotid artery flow remained affected. By ED 18.5, baseline embryonic carotid artery flow increased and descending aortic flow decreased versus non-caffeine-exposed embryos. Maternal treatment with the adenosine A(2A) receptor inhibitor reproduced the embryonic hemodynamic effects of maternal caffeine exposure. Adenosine A(2A) receptor gene expression levels of ED 11.5 embryo and ED 18.5 uterus were decreased. Results suggest that modest maternal caffeine exposure has adverse effects on developing embryonic CV function and growth, possibly mediated via adenosine A(2A) receptor blockade.

  10. Dietary electrolyte balance affects growth performance, amylase activity and metabolic response in the meagre (Argyrosomus regius).

    PubMed

    Magnoni, Leonardo J; Salas-Leiton, Emilio; Peixoto, Maria-João; Pereira, Luis; Silva-Brito, Francisca; Fontinha, Filipa; Gonçalves, José F M; Wilson, Jonathan M; Schrama, Johan W; Ozório, Rodrigo O A

    2017-03-16

    Dietary ion content is known to alter the acid-base balance in freshwater fish. The current study investigated the metabolic impact of acid-base disturbances produced by differences in dietary electrolyte balance (DEB) in the meagre (Argyrosomus regius), an euryhaline species. Changes in fish performance, gastric chyme characteristics, pH and ion concentrations in the bloodstream, digestive enzyme activities and metabolic rates were analyzed in meagre fed ad libitum two experimental diets (DEB 200 or DEB 700mEq/kg) differing in the Na2CO3 content for 69days. Fish fed the DEB 200 diet had 60-66% better growth performance than the DEB 700 group. Meagre consuming the DEB 200 diet were 90-96% more efficient than fish fed the DEB 700 diet at allocating energy from feed into somatic growth. The pH values in blood were significantly lower in the DEB 700 group 2h after feeding when compared to DEB 200, indicating that acid-base balance in meagre was affected by electrolyte balance in diet. Osmolality, and Na(+) and K(+) concentrations in plasma did not vary with the dietary treatment. Gastric chyme in the DEB 700 group had higher pH values, dry matter, protein and energy contents, but lower lipid content than in the DEB 200 group. Twenty-four hours after feeding, amylase activity was higher in the gastrointestinal tract of DEB 700 group when compared to the DEB 200 group. DEB 700 group had lower routine metabolic (RMR) and standard metabolic (SMR) rates, indicating a decrease in maintenance energy expenditure 48h after feeding the alkaline diet. The current study demonstrates that feeding meagre with an alkaline diet not only causes acid-base imbalance, but also negatively affects digestion and possibly nutrient assimilation, resulting in decreased growth performance.

  11. Defoliation negatively affects plant growth and the ectomycorrhizal community of Pinus pinaster in Spain.

    PubMed

    Pestaña, Montserrat; Santolamazza-Carbone, Serena

    2011-03-01

    In this work, by artificially reproducing severe (75%) and moderate (25%) defoliation on maritime pines Pinus pinaster in NW Spain, we investigated, under natural conditions, the consequences of foliage loss on reproduction, abundance, diversity and richness of the fungal symbionts growing belowground and aboveground. The effect of defoliation on tree growth was also assessed. Mature needles were clipped during April 2007 and 2008. Root samples were collected in June-July 2007 and 2008. Collection of sporocarps was performed weekly from April 2007 to April 2009. Taxonomic identity of ectomycorrhizal fungi was assessed by using the internal transcribed spacer (ITS) regions of rDNA through the polymerase chain reaction (PCR) method, subsequent direct sequencing and BLAST search. Ectomycorrhizal colonization was significantly reduced (from 54 to 42%) in 2008 by 75% defoliation, accompanied with a decline in species richness and diversity. On the other hand, sporocarp abundance, richness and diversity were not affected by foliage loss. Some ECM fungal symbionts, which are assumed to have a higher carbon cost according to the morphotypes structure, were reduced due to severe (75%) defoliation. Furthermore, 75% foliage loss consistently depressed tree growth, which in turn affected the ectomycorrhizal growth pattern. Defoliation impact on ECM symbionts largely depends on the percentage of foliage removal and on the number of defoliation bouts. Severe defoliation (75%) in the short term (2 years) changed the composition of the ECM community likely because root biomass would be adjusted to lower levels in parallel with the depletion of the aboveground plant biomass, which probably promoted the competition among mycorrhizal types for host resources. The persistence of fungal biomass in mycorrhizal roots would be crucial for nutrient up-take and recovery from defoliation stress of the host plants.

  12. Does Coral Disease Affect Symbiodinium? Investigating the Impacts of Growth Anomaly on Symbiont Photophysiology

    PubMed Central

    Burns, John Henrik Robert; Gregg, Toni Makani; Takabayashi, Misaki

    2013-01-01

    Growth anomaly (GA) is a commonly observed coral disease that impairs biological functions of the affected tissue. GA is prevalent at Wai ‘ōpae tide pools, southeast Hawai ‘i Island. Here two distinct forms of this disease, Type A and Type B, affect the coral, Montiporacapitata. While the effects of GA on biology and ecology of the coral host are beginning to be understood, the impact of this disease on the photophysiology of the dinoflagellate symbiont, Symbiodinium spp., has not been investigated. The GA clearly alters coral tissue structure and skeletal morphology and density. These tissue and skeletal changes are likely to modify not only the light micro-environment of the coral tissue, which has a direct impact on the photosynthetic potential of Symbiodinium spp., but also the physiological interactions within the symbiosis. This study utilized Pulse amplitude modulation fluorometry (PAM) to characterize the photophysiology of healthy and GA-affected M. capitata tissue. Overall, endosymbionts within GA-affected tissue exhibit reduced photochemical efficiency. Values of both Fv/Fm and ΔF/ Fm’ were significantly lower (p<0.01) in GA tissue compared to healthy and unaffected tissues. Tracking the photophysiology of symbionts over a diurnal time period enabled a comparison of symbiont responses to photosynthetically available radiation (PAR) among tissue conditions. Symbionts within GA tissue exhibited the lowest values of ΔF/Fm’ as well as the highest pressure over photosystem II (p<0.01). This study provides evidence that the symbionts within GA-affected tissue are photochemically compromised compared to those residing in healthy tissue. PMID:23967301

  13. Larval diapause termination in the bamboo borer, Omphisa fuscidentalis

    PubMed Central

    Suang, Suphawan; Manaboon, Manaporn; Singtripop, Tippawan; Hiruma, Kiyoshi; Kaneko, Yu; Tiansawat, Pimonrat; Neumann, Peter; Chantawannakul, Panuwan

    2017-01-01

    In insects, juvenile hormone (JH) and 20-hydroxyecdysone (20E) regulate larval growth and molting. However, little is known about how this cooperative control is terminating larval diapause especially in the bamboo borer, Omphisa fuscidentalis. In both in vivo and in vitro experiments, we here measured the expression levels of genes which were affected by juvenile hormone analogue (JHA: S-methoprene) and 20-hydroxyecdysone (20E) in diapausing O. fuscidentalis larvae. Corresponding mRNA expression changes in the subesophageal ganglion (SG) and prothoracic gland (PG) were evaluated using qRT-PCR. The data showed similar response patterns of JH receptor gene (OfMet), diapause hormone gene (OfDH-PBAN), ecdysone receptor genes (OfEcR-A and OfEcR-B1) and ecdysone inducible genes (OfBr-C, OfE75A, OfE75B, OfE75C and OfHR3). JHA induced the expressions of OfMet and OfDH-PBAN in both SG and PG, whereas ecdysone receptor genes and ecdysone inducible genes were induced by JHA only in PG. For 20E treatment group, expressions of ecdysone receptor genes and ecdysone inducible genes in both SG and PG were increased by 20E injection. In addition, the in vitro experiments showed that OfMet and OfDH-PBAN were up-regulated by JHA alone, but ecdysone receptor genes and ecdysone inducible genes were up-regulated by JHA and 20E. However, OfMet and OfDH-PBAN in the SG was expressed faster than OfMet and OfDH-PBAN in the PG and the expression of ecdysone receptor genes and ecdysone inducible genes induced by JHA was much later than observed for 20E. These results indicate that JHA might stimulate the PG indirectly via factors (OfMet and OfDH-PBAN) in the SG, which might be a regulatory mechanism for larval diapause termination in O. fuscidentalis. PMID:28369111

  14. Integrin antagonists affect growth and pathfinding of ventral motor nerves in the trunk of embryonic zebrafish.

    PubMed

    Becker, Thomas; McLane, Mary Ann; Becker, Catherina G

    2003-05-01

    Integrins are thought to be important receptors for extracellular matrix (ECM) components on growing axons. Ventral motor axons in the trunk of embryonic zebrafish grow in a midsegmental pathway through an environment rich in ECM components. To test the role of integrins in this process, integrin antagonists (the disintegrin echistatin in native and recombinant form, as well as the Arg-Gly-Asp-Ser peptide) were injected into embryos just prior to axon outgrowth at 14-16 h postfertilization (hpf). All integrin antagonists affected growth of ventral motor nerves in a similar way and native echistatin was most effective. At 24 hpf, when only the three primary motor axons per trunk hemisegment had grown out, 80% (16 of 20) of the embryos analyzed had abnormal motor nerves after injection of native echistatin, corresponding to 19% (91 of 480) of all nerves. At 33 hpf, when secondary motor axons were present in the pathway, 100% of the embryos were affected (24 of 24), with 20% of all nerves analyzed (196 of 960) being abnormal. Phenotypes comprised abnormal branching (64% of all abnormal nerves) and truncations (36% of all abnormal nerves) of ventral motor nerves at 24 hpf and mostly branching of the nerves at 33 hpf (94% of all abnormal nerves). Caudal branches were at least twice as frequent as rostral branches. Surrounding trunk tissue and a number of other axon fascicles were apparently not affected by the injections. Thus integrin function contributes to both growth and pathfinding of axons in ventral motor nerves in the trunk of zebrafish in vivo.

  15. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    PubMed

    Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

    2016-01-01

    Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions.

  16. Survivin inhibitor YM155 suppresses gastric cancer xenograft growth in mice without affecting normal tissues.

    PubMed

    Cheng, Xiao Jiao; Lin, Jia Cheng; Ding, Yan Fei; Zhu, Liming; Ye, Jing; Tu, Shui Ping

    2016-02-09

    Survivin overexpression is associated with poor prognosis of human gastric cancer, and is a target for gastric cancer therapy. YM155 is originally identified as a specific inhibitor of survivin. In this study, we investigated the antitumor effect of YM155 on human gastric cancer. Our results showed that YM155 treatment significantly inhibited cell proliferation, reduced colony formation and induced apoptosis of gastric cancer cells in a dose-dependent manner. Accordingly, YM155 treatment significantly decreased survivin expression without affecting XIAP expression and increased the cleavage of apoptosis-associated proteins caspase 3, 7, 8, 9. YM155 significantly inhibited sphere formation of gastric cancer cells, suppressed expansion and growth of the formed spheres (cancer stem cell-like cells, CSCs) and downregulated the protein levels of β-catenin, c-Myc, Cyclin D1 and CD44 in gastric cancer cells. YM155 infusion at 5 mg/kg/day for 7 days markedly inhibited growth of gastric cancer xenograft in a nude mouse model. Immunohistochemistry staining and Western Blot showed that YM155 treatment inhibited expression of survivin and CD44, induced apoptosis and reduced CD44+ CSCs in xenograft tumor tissues in vivo. No obvious pathological changes were observed in organs (e.g. heart, liver, lung and kidney) in YM155-treated mice. Our results demonstrated that YM155 inhibits cell proliferation, induces cell apoptosis, reduces cancer stem cell expansion, and inhibits xenograft tumor growth in gastric cancer cells. Our results elucidate a new mechanism by which YM155 inhibits gastric cancer growth by inhibition of CSCs. YM155 may be a promising agent for gastric cancer treatment.

  17. Unilateral Nasal Obstruction during Later Growth Periods Affects Craniofacial Muscles in Rats

    PubMed Central

    Uchima Koecklin, Karin H.; Hiranuma, Maya; Kato, Chiho; Funaki, Yukiha; Kataguchi, Taku; Yabushita, Tadachika; Kokai, Satoshi; Ono, Takashi

    2017-01-01

    Nasal obstruction can occur at different life stages. In early stages of life the respiratory system is still under development, maturing during the growth period. Previous studies have shown that nasal obstruction in neonatal rats alters craniofacial function. However, little is known about the effects of nasal obstruction that develops during later growth periods. The aim of this study was to investigate the effects of nasal obstruction during later periods of growth on the functional characteristics of the jaw-opening reflex (JOR) and tongue-protruding muscles. In total, 102 6-day-old male Wistar rats were randomized into either a control or experimental group (both n = 51). In order to determine the appropriate timing of nasal obstruction, the saturation of arterial oxygen (SpO2) was monitored at 8 days, and at 3, 5, 7, 9, and 11 weeks in the control group. Rats in the experimental group underwent unilateral nasal obstruction at the age of 5 weeks. The SpO2 was monitored at 7, 9, and 11 weeks in the experimental group. The electromyographic responses of JOR and the contractile properties of the tongue-protruding muscles were recorded at 7, 9, and 11 weeks. In the control group, SpO2 decreased until 5 weeks of age, and remained relatively stable until 11 weeks of age. The SpO2 was significantly lower in the experimental group than in the control. In the experimental group, JOR changes included a longer latency and smaller peak-to-peak amplitude, while changes in the contractile properties of the tongue-protruding muscles included larger twitch and tetanic forces, and a longer half-decay time. These results suggest that nasal obstruction during later growth periods may affect craniofacial function. PMID:28119621

  18. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    PubMed Central

    Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

    2016-01-01

    Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions. PMID:26735689

  19. Temperature-induced elevation of basal metabolic rate does not affect testis growth in great tits.

    PubMed

    Caro, Samuel P; Visser, Marcel E

    2009-07-01

    The timing of reproduction varies from year to year in many bird species. To adjust their timing to the prevailing conditions of that year, birds use cues from their environment. However, the relative importance of these cues, such as the initial predictive (e.g. photoperiod) and the supplemental factors (e.g. temperature), on the seasonal sexual development are difficult to distinguish. In particular, the fine-tuning effect of temperature on gonadal growth is not well known. One way temperature may affect timing is via its strong effect on energy expenditure as gonadal growth is an energy-demanding process. To study the interaction of photoperiod and temperature on gonadal development, we first exposed 35 individually housed male great tits (Parus major) to mid-long days (after 6 weeks of 8 h L:16 h D at 15 degrees C, photoperiod was set to 13 h L:11 h D at 15 degrees C). Two weeks later, for half of the males the temperature was set to 8 degrees C, and for the other half to 22 degrees C. Unilateral laparotomies were performed at weeks 5 (i.e one week before the birds were transferred to mid-long days), 8 and 11 to measure testis size. Two measures of basal metabolic rate (BMR) were performed at the end of the experiment (weeks 11 and 12). Testis size increased significantly during the course of the experiment, but independently of the temperature treatment. BMR was significantly higher in birds exposed to the cold treatment. These results show that temperature-related elevation of BMR did not impair the long-day-induced testis growth in great tits. As a consequence, temperature may not be a crucial cue and/or constraint factor in the fine-tuning of the gonadal recrudescence in male great tits, and testis growth is not a high energy-demanding seasonal process.

  20. Stiff Mutant Genes of Phycomyces Affect Turgor Pressure and Wall Mechanical Properties to Regulate Elongation Growth Rate

    PubMed Central

    Ortega, Joseph K. E.; Munoz, Cindy M.; Blakley, Scott E.; Truong, Jason T.; Ortega, Elena L.

    2012-01-01

    Regulation of cell growth is paramount to all living organisms. In plants, algae and fungi, regulation of expansive growth of cells is required for development and morphogenesis. Also, many sensory responses of stage IVb sporangiophores of Phycomyces blakesleeanus are produced by regulating elongation growth rate (growth responses) and differential elongation growth rate (tropic responses). “Stiff” mutant sporangiophores exhibit diminished tropic responses and are found to be defective in at least five genes; madD, E, F, G, and J. Prior experimental research suggests that the defective genes affect growth regulation, but this was not verified. All the growth of the single-celled stalk of the stage IVb sporangiophore occurs in a short region termed the “growth zone.” Prior experimental and theoretical research indicates that elongation growth rate of the stage IVb sporangiophore can be regulated by controlling the cell wall mechanical properties within the growth zone and the magnitude of the turgor pressure. A quantitative biophysical model for elongation growth rate is required to elucidate the relationship between wall mechanical properties and turgor pressure during growth regulation. In this study, it is hypothesized that the mechanical properties of the wall within the growth zone of stiff mutant sporangiophores are different compared to wild type (WT). A biophysical equation for elongation growth rate is derived for fungal and plant cells with a growth zone. Two strains of stiff mutants are studied, C149 madD120 (−) and C216 geo- (−). Experimental results demonstrate that turgor pressure is larger but irreversible wall deformation rates within the growth zone and growth zone length are smaller for stiff mutant sporangiophores compared to WT. These findings can explain the diminished tropic responses of the stiff mutant sporangiophores. It is speculated that the defective genes affect the amount of wall-building material delivered to the inner cell

  1. Stiff mutant genes of phycomyces affect turgor pressure and wall mechanical properties to regulate elongation growth rate.

    PubMed

    Ortega, Joseph K E; Munoz, Cindy M; Blakley, Scott E; Truong, Jason T; Ortega, Elena L

    2012-01-01

    Regulation of cell growth is paramount to all living organisms. In plants, algae and fungi, regulation of expansive growth of cells is required for development and morphogenesis. Also, many sensory responses of stage IVb sporangiophores of Phycomyces blakesleeanus are produced by regulating elongation growth rate (growth responses) and differential elongation growth rate (tropic responses). "Stiff" mutant sporangiophores exhibit diminished tropic responses and are found to be defective in at least five genes; madD, E, F, G, and J. Prior experimental research suggests that the defective genes affect growth regulation, but this was not verified. All the growth of the single-celled stalk of the stage IVb sporangiophore occurs in a short region termed the "growth zone." Prior experimental and theoretical research indicates that elongation growth rate of the stage IVb sporangiophore can be regulated by controlling the cell wall mechanical properties within the growth zone and the magnitude of the turgor pressure. A quantitative biophysical model for elongation growth rate is required to elucidate the relationship between wall mechanical properties and turgor pressure during growth regulation. In this study, it is hypothesized that the mechanical properties of the wall within the growth zone of stiff mutant sporangiophores are different compared to wild type (WT). A biophysical equation for elongation growth rate is derived for fungal and plant cells with a growth zone. Two strains of stiff mutants are studied, C149 madD120 (-) and C216 geo- (-). Experimental results demonstrate that turgor pressure is larger but irreversible wall deformation rates within the growth zone and growth zone length are smaller for stiff mutant sporangiophores compared to WT. These findings can explain the diminished tropic responses of the stiff mutant sporangiophores. It is speculated that the defective genes affect the amount of wall-building material delivered to the inner cell wall.

  2. Fibroblast growth factor 9 is a novel modulator of negative affect

    PubMed Central

    Aurbach, Elyse L.; Inui, Edny Gula; Turner, Cortney A.; Hagenauer, Megan H.; Prater, Katherine E.; Li, Jun Z.; Absher, Devin; Shah, Najmul; Blandino, Peter; Bunney, William E.; Myers, Richard M.; Barchas, Jack D.; Schatzberg, Alan F.; Watson, Stanley J.; Akil, Huda

    2015-01-01

    Both gene expression profiling in postmortem human brain and studies using animal models have implicated the fibroblast growth factor (FGF) family in affect regulation and suggest a potential role in the pathophysiology of major depressive disorder (MDD). FGF2, the most widely characterized family member, is down-regulated in the depressed brain and plays a protective role in rodent models of affective disorders. By contrast, using three microarray analyses followed by quantitative RT-PCR confirmation, we show that FGF9 expression is up-regulated in the hippocampus of individuals with MDD, and that FGF9 expression is inversely related to the expression of FGF2. Because little is known about FGF9’s function in emotion regulation, we used animal models to shed light on its potential role in affective function. We found that chronic social defeat stress, an animal model recapitulating some aspects of MDD, leads to a significant increase in hippocampal FGF9 expression, paralleling the elevations seen in postmortem human brain tissue. Chronic intracerebroventricular administration of FGF9 increased both anxiety- and depression-like behaviors. In contrast, knocking down FGF9 expression in the dentate gyrus of the hippocampus using a lentiviral vector produced a decrease in FGF9 expression and ameliorated anxiety-like behavior. Collectively, these results suggest that high levels of hippocampal FGF9 play an important role in the development or expression of mood and anxiety disorders. We propose that the relative levels of FGF9 in relation to other members of the FGF family may prove key to understanding vulnerability or resilience in affective disorders. PMID:26351673

  3. Effects of hatching time for larval ambystomatid salamanders

    USGS Publications Warehouse

    Boone, M.D.; Scott, D.E.; Niewiarowski, P.H.

    2002-01-01

    In aquatic communities, the phenology of breeding may influence species interactions. In the early-breeding marbled salamander, Ambystoma opacum, timing of pond filling may determine whether interactions among larvae are competitive or predatory. The objectives of our studies were to determine how time of egg hatching affected size, larval period, and survival to metamorphosis in A. opacum, and if early-hatching in A. opacum influenced the competitive and predator-prey relationships with smaller larvae of the mole salamander, Ambystoma talpoideum. Salamander larvae were reared from hatching through metamorphosis in large, outdoor enclosures located in a natural temporary pond in Aiken County, South Carolina, in two experiments. In study 1, we reared early- and late-hatching A. opacum larvae separately from hatching through metamorphosis. In study 2, we examined how early- versus late-hatching A. opacum affected a syntopic species, A. talpoideum. In general, early-hatching A. opacum were larger and older at metamorphosis, had greater survival, and left the pond earlier than late-hatching larvae. Ambystoma talpoideum reared in the presence of early-hatching A. opacum had lower survival than in controls, suggesting that A. opacum may predate upon A. talpoideum when they gain a growth advantage over later-hatching larvae. Our studies demonstrate that time of pond filling and phenology of breeding may influence population dynamics and alter the nature of relationships that develop among species.

  4. The protective function of personal growth initiative among a genocide-affected population in Rwanda.

    PubMed

    Blackie, Laura E R; Jayawickreme, Eranda; Forgeard, Marie J C; Jayawickreme, Nuwan

    2015-07-01

    The aim of the current study was to investigate the extent to which individual differences in personal growth initiative (PGI) were associated with lower reports of functional impairment of daily activities among a genocide-affected population in Rwanda. PGI measures an individual's motivation to develop as a person and the extent to which he or she is active in setting goals that work toward achieving self-improvement. We found that PGI was negatively associated with functional impairment when controlling for depression, posttraumatic stress disorder, and other demographic factors. Our results suggest that PGI may constitute an important mindset for facilitating adaptive functioning in the aftermath of adversity and in the midst of psychological distress, and as such they might have practical applications for the development of intervention programs.

  5. Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof.

    PubMed

    Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy

    2016-05-15

    Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%-26% volumetric moisture content) and temperature (21°C-36°C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat

  6. Cronobacter sakazakii in foods and factors affecting its survival, growth, and inactivation.

    PubMed

    Beuchat, Larry R; Kim, Hoikyung; Gurtler, Joshua B; Lin, Li-Chun; Ryu, Jee-Hoon; Richards, Glenner M

    2009-12-31

    Cronobacter sakazakii has been isolated from a wide range of environmental sources and from several foods of animal and plant origin. While infections caused by C. sakazakii have predominantly involved neonates and infants, its presence on or in foods other than powdered infant formula raises concern about the safety risks these foods pose to immunocompromised consumers. We have done a series of studies to better understand the survival and growth characteristics of C. sakazakii in infant formula, infant cereal, fresh-cut produce, and juices made from fresh produce. Over a 12-month storage period, the pathogen survived better in dried formula and cereal at low a(w) (0.25-0.30) than at high a(w) (0.69-0.82) and at 4 degrees C compared to 30 degrees C. C. sakazakii grows in formulas and cereals reconstituted with water or milk and held at 12-30 degrees C. The composition of formulas or cereals does not markedly affect the rate of growth. C. sakazakii grows well on fresh-cut apple, cantaloupe, watermelon, cabbage, carrot, cucumber, lettuce, and tomato at 25 degrees C and in some types of produce at 12 degrees C. Treatment of fresh fruits and vegetables with sanitizers such as chlorine, chlorine dioxide, and a peroxyacetic acid-based solution causes reductions of 1.6-5.4 log CFU/apple, tomato, and lettuce. Cells of C. sakazakii in biofilms formed on stainless steel and enteral feeding tubes or dried on the surface of stainless steel have increased resistance to disinfectants. Death of cells in biofilms is affected by atmospheric relative humidity. These studies have contributed to a better understanding of the behavior of C. sakazakii in and on foods and on food-contact surfaces, thereby enabling the development of more effective strategies and interventions for its control.

  7. Anopheles larval abundance and diversity in three rice agro-village complexes Mwea irrigation scheme, central Kenya

    PubMed Central

    2010-01-01

    Background The diversity and abundance of Anopheles larvae has significant influence on the resulting adult mosquito population and hence the dynamics of malaria transmission. Studies were conducted to examine larval habitat dynamics and ecological factors affecting survivorship of aquatic stages of malaria vectors in three agro-ecological settings in Mwea, Kenya. Methods Three villages were selected based on rice husbandry and water management practices. Aquatic habitats in the 3 villages representing planned rice cultivation (Mbui Njeru), unplanned rice cultivation (Kiamachiri) and non-irrigated (Murinduko) agro-ecosystems were sampled every 2 weeks to generate stage-specific estimates of mosquito larval densities, relative abundance and diversity. Records of distance to the nearest homestead, vegetation coverage, surface debris, turbidity, habitat stability, habitat type, rice growth stage, number of rice tillers and percent Azolla cover were taken for each habitat. Results Captures of early, late instars and pupae accounted for 78.2%, 10.9% and 10.8% of the total Anopheles immatures sampled (n = 29,252), respectively. There were significant differences in larval abundance between 3 agro-ecosystems. The village with 'planned' rice cultivation had relatively lower Anopheles larval densities compared to the villages where 'unplanned' or non-irrigated. Similarly, species composition and richness was higher in the two villages with either 'unplanned' or limited rice cultivation, an indication of the importance of land use patterns on diversity of larval habitat types. Rice fields and associated canals were the most productive habitat types while water pools and puddles were important for short periods during the rainy season. Multiple logistic regression analysis showed that presence of other invertebrates, percentage Azolla cover, distance to nearest homestead, depth and water turbidity were the best predictors for Anopheles mosquito larval abundance. Conclusion

  8. Adult beetles compensate for poor larval food conditions.

    PubMed

    Müller, Thorben; Müller, Caroline

    2016-05-01

    Life history traits of herbivores are highly influenced by the quality of their hosts, i.e., the composition of primary and secondary plant metabolites. In holometabolous insects, larvae and adults may face different host plants, which differ in quality. It has been hypothesised that adult fitness is either highest when larval and adult environmental conditions match (environmental matching) or it may be mainly determined by optimal larval conditions (silver spoon effect). Alternatively, the adult stage may be most decisive for the actual fitness, independent of larval food exposure, due to adult compensation ability. To determine the influence of constant versus changing larval and adult host plant experiences on growth performance, fitness and feeding preferences, we carried out a match-mismatch experiment using the mustard leaf beetle, Phaedon cochleariae. Larvae and adults were either constantly reared on watercress (natural host) or cabbage (crop plant) or were switched after metamorphosis to the other host. Growth, reproductive traits and feeding preferences were determined repeatedly over lifetime and host plant quality traits analysed. Differences in the host quality led to differences in the development time and female reproduction. Egg numbers were significantly influenced by the host plant species experienced by the adults. Thus, adults were able to compensate for poor larval conditions. Likewise, the current host experience was most decisive for feeding preferences; in adult beetles a feeding preference was shaped regardless of the larval host plant. Larvae or adults reared on the more nutritious host, cabbage, showed a higher preference for this host. Hence, beetles most likely develop a preference when gaining a direct positive feedback in terms of an improved performance, whereby the current experience matters the most. Highly nutritious crop plants may be, in consequence, all the more exploited by potential pests that may show a high plasticity in

  9. Zebra pattern in rocks as a function of grain growth affected by second-phase particles

    NASA Astrophysics Data System (ADS)

    Kelka, Ulrich; Koehn, Daniel; Beaudoin, Nicolas

    2015-09-01

    In this communication we present a simple microdynamic model which can explain the beginning of the zebra pattern formation in rocks. The two dimensional model consists of two main processes, mineral replacement along a reaction front, and grain boundary migration affected by impurities. In the numerical model we assume that an initial distribution of second-phase particles is present due to sedimentary layering. The reaction front percolates the model and redistributes second-phase particles by shifting them until the front is saturated and drops the particles again. This produces and enhances initial layering. Grain growth is hindered in layers with high second-phase particle concentrations whereas layers with low concentrations coarsen. Due to the grain growth activity in layers with low second-phase particle concentrations these impurities are collected at grain boundaries and the crystals become very clean. Therefore the white layers in the pattern contain large grains with low concentration of second-phase particles, whereas the dark layers contain small grains with a large second-phase particle concentration.

  10. Estimation of the growth kinetic parameters of Bacillus cereus spores as affected by pulsed light treatment.

    PubMed

    Aguirre, Juan S; de Fernando, Gonzalo García; Hierro, Eva; Hospital, Xavier F; Ordóñez, Juan A; Fernández, Manuela

    2015-06-02

    Quantitative microbial risk assessment requires the knowledge of the effect of food preservation technologies on the growth parameters of the survivors of the treatment. This is of special interest in the case of the new non-thermal technologies that are being investigated for minimal processing of foods. This is a study on the effect of pulsed light technology (PL) on the lag phase of Bacillus cereus spores surviving the treatment and the maximum growth rate (μmax) of the survivors after germination. The D value was estimated as 0.35 J/cm(2) and our findings showed that PL affected the kinetic parameters of the microorganism. A log linear relationship was observed between the lag phase and the intensity of the treatment. Increasing the lethality lengthened the mean lag phase and proportionally increased its variability. A polynomial regression was fitted between the μmax of the survivors and the inactivation achieved. The μmax decreased as intensity increased. From these data, and their comparison to published results on the effect of heat and e-beam irradiation on B. cereus spores, it was observed that the shelf-life of PL treated foods would be longer than those treated with heat and similar to irradiated ones. These findings offer information of interest for the implementation of PL for microbial decontamination in the food industry.

  11. Cellular glycosylation affects Herceptin binding and sensitivity of breast cancer cells to doxorubicin and growth factors

    PubMed Central

    Peiris, Diluka; Spector, Alexander F.; Lomax-Browne, Hannah; Azimi, Tayebeh; Ramesh, Bala; Loizidou, Marilena; Welch, Hazel; Dwek, Miriam V.

    2017-01-01

    Alterations in protein glycosylation are a key feature of oncogenesis and have been shown to affect cancer cell behaviour perturbing cell adhesion, favouring cell migration and metastasis. This study investigated the effect of N-linked glycosylation on the binding of Herceptin to HER2 protein in breast cancer and on the sensitivity of cancer cells to the chemotherapeutic agent doxorubicin (DXR) and growth factors (EGF and IGF-1). The interaction between Herceptin and recombinant HER2 protein and cancer cell surfaces (on-rate/off-rate) was assessed using a quartz crystal microbalance biosensor revealing an increase in the accessibility of HER2 to Herceptin following deglycosylation of cell membrane proteins (deglycosylated cells Bmax: 6.83 Hz; glycosylated cells Bmax: 7.35 Hz). The sensitivity of cells to DXR and to growth factors was evaluated using an MTT assay. Maintenance of SKBR-3 cells in tunicamycin (an inhibitor of N-linked glycosylation) resulted in an increase in sensitivity to DXR (0.1 μM DXR P < 0.001) and a decrease in sensitivity to IGF-1 alone and to IGF-1 supplemented with EGF (P < 0.001). This report illustrates the importance of N-linked glycosylation in modulating the response of cancer cells to chemotherapeutic and biological treatments and highlights the potential of glycosylation inhibitors as future combination treatments for breast cancer. PMID:28223691

  12. Growth of non-Saccharomyces yeasts affects nutrient availability for Saccharomyces cerevisiae during wine fermentation.

    PubMed

    Medina, Karina; Boido, Eduardo; Dellacassa, Eduardo; Carrau, Francisco

    2012-07-02

    Yeast produces numerous secondary metabolites during fermentation that impact final wine quality. Although it is widely recognized that growth of diverse non-Saccharomyces (NS) yeast can positively affect flavor complexity during Saccharomyces cerevisiae wine fermentation, the inability to control spontaneous or co-fermentation processes by NS yeast has restricted their use in winemaking. We selected two NS yeasts from our Uruguayan native collection to study NS-S. cerevisiae interactions during wine fermentation. The selected strains of Hanseniaspora vineae and Metschnikowia pulcherrima had different yeast assimilable nitrogen consumption profiles and had different effects on S. cerevisiae fermentation and growth kinetics. Studies in which we varied inoculum size and using either simultaneous or sequential inoculation of NS yeast and S. cerevisiae suggested that competition for nutrients had a significant effect on fermentation kinetics. Sluggish fermentations were more pronounced when S. cerevisiae was inoculated 24h after the initial stage of fermentation with a NS strain compared to co-inoculation. Monitoring strain populations using differential WL nutrient agar medium and fermentation kinetics of mixed cultures allowed for a better understanding of strain interactions and nutrient addition effects. Limitation of nutrient availability for S. cerevisiae was shown to result in stuck fermentations as well as to reduce sensory desirability of the resulting wine. Addition of diammonium phosphate (DAP) and a vitamin mix to a defined medium allowed for a comparison of nutrient competition between strains. Addition of DAP and the vitamin mix was most effective in preventing stuck fermentations.

  13. A review on the factors affecting mite growth in stored grain commodities.

    PubMed

    Collins, D A

    2012-03-01

    A thorough review of the literature has identified the key factors and interactions that affect the growth of mite pests on stored grain commodities. Although many factors influence mite growth, the change and combinations of the physical conditions (temperature, relative humidity and/or moisture content) during the storage period are likely to have the greatest impact, with biological factors (e.g. predators and commodity) playing an important role. There is limited information on the effects of climate change, light, species interactions, local density dependant factors, spread of mycotoxins and action thresholds for mites. A greater understanding of these factors may identify alternative control techniques. The ability to predict mite population dynamics over a range of environmental conditions, both physical and biological, is essential in providing an early warning of mite infestations, advising when appropriate control measures are required and for evaluating control measures. This information may provide a useful aid in predicting and preventing mite population development as part of a risk based decision support system.

  14. A pathway of bisphenol A affecting mineral element contents in plant roots at different growth stages.

    PubMed

    Xia, Binxin; Wang, Lihong; Nie, Lijun; Zhou, Qing; Huang, Xiaohua

    2017-01-01

    Bisphenol A (BPA), an environmental endocrine disruptor, is an important industrial raw material. The wide use of BPA has increased the risk of BPA release into the environment, and it has become a new environmental pollutant. In this work, the ecological deleterious effects of this new pollutant on soybean roots at different growth stages were investigated by determining the contents of mineral elements (P, K, Ca, and Mg) and analyzing root activity and the activities of critical respiratory enzymes (hexokinase, phosphofructokinase, pyruvate kinase, and isocitrate dehydrogenase). Our results revealed that low dose (1.5mg/L) of BPA increased the levels of P, K, Mg, and Ca in soybean roots at different growth stages. Whereas, high doses (6.0 and 12.0mg/L) of BPA decreased the levels of P, K, and Mg contents in a dose-dependent manner. BPA had a promotive effect on the content of Ca in soybean roots. Synchronous observation showed that the aforementioned dual response to BPA were also observed in the root activity and respiratory enzyme activities. The effects of BPA on the mineral element contents, root activity and respiratory enzyme activities in soybean roots at different growth stages followed the order: flowering and podding stage>seed-filling stage>seedling stage (mineral element contents); seedling stage>flowering and podding stage>seed-filling stage (root activity and respiratory enzyme activities). In a word, the response of plant root activity and respiratory enzyme activities to BPA pollution is a pathway of BPA affecting mineral element contents in plant roots.

  15. Salivary enzymes and exhaled air affect Streptococcus salivarius growth and physiological state in complemented artificial saliva.

    PubMed

    Roger, P; Harn-Arsa, S; Delettre, J; Béal, C

    2011-12-01

    To better understand the phenomena governing the establishment of the oral bacterium Streptococcus salivarius in the mouth, the effect of some environmental factors has been studied in complemented artificial saliva, under oral pH and temperature conditions. Three salivary enzymes at physiological concentrations were tested: peroxidase, lysozyme and amylase, as well as injection of exhaled air. Injection of air containing 5% CO2 and 16% O2 induced a deleterious effect on S. salivarius K12, mainly by increasing redox potential. Addition of lysozyme slightly affected the physiological state of S. salivarius by altering membrane integrity. In contrast, peroxidase was not detrimental as it made it possible to decrease the redox potential. The addition of amylase reduced the specific growth rate of S. salivarius by formation of a complex with amylase and mucins, but led to high final biomass, as a result of enzymatic degradation of some nutrients. Finally, this work demonstrated that salivary enzymes had a slight impact on S. salivarius behaviour. It can thus be concluded that this bacterium was well adapted to in-mouth conditions, as it was able to resist certain salivary enzymes, even if tolerance to expired air was affected, as a result of an increased redox potential.

  16. Elastic modulus affects the growth and differentiation of neural stem cells

    PubMed Central

    Jiang, Xian-feng; Yang, Kai; Yang, Xiao-qing; Liu, Ying-fu; Cheng, Yuan-chi; Chen, Xu-yi; Tu, Yue

    2015-01-01

    It remains poorly understood if carrier hardness, elastic modulus, and contact area affect neural stem cell growth and differentiation. Tensile tests show that the elastic moduli of Tiansu and SMI silicone membranes are lower than that of an ordinary dish, while the elastic modulus of SMI silicone membrane is lower than that of Tiansu silicone membrane. Neural stem cells from the cerebral cortex of embryonic day 16 Sprague-Dawley rats were seeded onto ordinary dishes as well as Tiansu silicone membrane and SMI silicone membrane. Light microscopy showed that neural stem cells on all three carriers show improved adherence. After 7 days of differentiation, neuron specific enolase, glial fibrillary acidic protein, and myelin basic protein expression was detected by immunofluorescence. Moreover, flow cytometry revealed a higher rate of neural stem cell differentiation into astrocytes on Tiansu and SMI silicone membranes than on the ordinary dish, which was also higher on the SMI than the Tiansu silicone membrane. These findings confirm that all three cell carrier types have good biocompatibility, while SMI and Tiansu silicone membranes exhibit good mechanical homogenization. Thus, elastic modulus affects neural stem cell differentiation into various nerve cells. Within a certain range, a smaller elastic modulus results in a more obvious trend of cell differentiation into astrocytes. PMID:26604916

  17. How Hydrogen Bonds Affect the Growth of Reverse Micelles around Coordinating Metal Ions.

    PubMed

    Qiao, Baofu; Demars, Thomas; Olvera de la Cruz, Monica; Ellis, Ross J

    2014-04-17

    Extensive research on hydrogen bonds (H-bonds) have illustrated their critical role in various biological, chemical and physical processes. Given that existing studies are predominantly performed in aqueous conditions, how H-bonds affect both the structure and function of aggregates in organic phase is poorly understood. Herein, we investigate the role of H-bonds on the hierarchical structure of an aggregating amphiphile-oil solution containing a coordinating metal complex by means of atomistic molecular dynamics simulations and X-ray techniques. For the first time, we show that H-bonds not only stabilize the metal complex in the hydrophobic environment by coordinating between the Eu(NO3)3 outer-sphere and aggregating amphiphiles, but also affect the growth of such reverse micellar aggregates. The formation of swollen, elongated reverse micelles elevates the extraction of metal ions with increased H-bonds under acidic condition. These new insights into H-bonds are of broad interest to nanosynthesis and biological applications, in addition to metal ion separations.

  18. Effects of beach morphology and waves on onshore larval transport

    NASA Astrophysics Data System (ADS)

    Fujimura, A.; Reniers, A.; Paris, C. B.; Shanks, A.; MacMahan, J.; Morgan, S.

    2015-12-01

    Larvae of intertidal species grow offshore, and migrate back to the shore when they are ready to settle on their adult substrates. In order to reach the habitat, they must cross the surf zone, which is characterized as a semi-permeable barrier. This is accomplished through physical forcing (i.e., waves and current) as well as their own behavior. Two possible scenarios of onshore larval transport are proposed: Negatively buoyant larvae stay in the bottom boundary layer because of turbulence-dependent sinking behavior, and are carried toward the shore by streaming of the bottom boundary layer; positively buoyant larvae move to the shore during onshore wind events, and sink to the bottom once they encounter high turbulence (i.e., surf zone edge), where they are carried by the bottom current toward the shore (Fujimura et al. 2014). Our biophysical Lagrangian particle tracking model helps to explain how beach morphology and wave conditions affect larval distribution patterns and abundance. Model results and field observations show that larval abundance in the surf zone is higher at mildly sloped, rip-channeled beaches than at steep pocket beaches. Beach attributes are broken up to examine which and how beach configuration factors affect larval abundance. Modeling with alongshore uniform beaches with variable slopes reveal that larval populations in the surf zone are negatively correlated with beach steepness. Alongshore variability enhances onshore larval transport because of increased cross-shore water exchange by rip currents. Wave groups produce transient rip currents and enhance cross-shore exchange. Effects of other wave components, such as wave height and breaking wave rollers are also considered.

  19. Does Atrazine Influence Larval Development and Sexual Differentiation in Xenopus laevis?

    PubMed Central

    Kloas, Werner; Lutz, Ilka; Springer, Timothy; Krueger, Henry; Wolf, Jeff; Holden, Larry; Hosmer, Alan

    2009-01-01

    Debate and controversy exists concerning the potential for the herbicide atrazine to cause gonadal malformations in developing Xenopus laevis. Following review of the existing literature the U.S. Environmental Protection Agency required a rigorous investigation conducted under standardized procedures. X. laevis tadpoles were exposed to atrazine at concentrations of 0.01, 0.1, 1, 25, or 100 μg/l from day 8 postfertilization (dpf) until completion of metamorphosis or dpf 83, whichever came first. Nearly identical experiments were performed in two independent laboratories: experiment 1 at Wildlife International, Ltd. and experiment 2 at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB). Both experiments employed optimized animal husbandry procedures and environmental conditions in validated flow-through exposure systems. The two experiments demonstrated consistent survival, growth, and development of X. laevis tadpoles, and all measured parameters were within the expected ranges and were comparable in negative control and atrazine-treated groups. Atrazine, at concentrations up to 100 μg/l, had no effect in either experiment on the percentage of males or the incidence of mixed sex as determined by histological evaluation. In contrast, exposure of larval X. laevis to 0.2 μg 17β-estradiol/l as the positive control resulted in gonadal feminization. Instead of an even distribution of male and female phenotypes, percentages of males:females:mixed sex were 19:75:6 and 22:60:18 in experiments 1 and 2, respectively. These studies demonstrate that long-term exposure of larval X. laevis to atrazine at concentrations ranging from 0.01 to 100 μg/l does not affect growth, larval development, or sexual differentiation. PMID:19008211

  20. Non-additive response of larval ringed salamanders to intraspecific density.

    PubMed

    Ousterhout, Brittany H; Semlitsch, Raymond D

    2016-04-01

    Conditions experienced in early developmental stages can have long-term consequences for individual fitness. High intraspecific density during the natal period can affect juvenile and eventually adult growth rates, metabolism, immune function, survival, and fecundity. Despite the important ecological and evolutionary effects of early developmental density, the form of the relationship between natal density and resulting juvenile phenotype is poorly understood. To test competing hypotheses explaining responses to intraspecific density, we experimentally manipulated the initial larval density of ringed salamanders (Ambystoma annulatum), a pond-breeding amphibian, over 11 densities. We modeled the functional form of the relationship between natal density and juvenile traits, and compared the relative support for the various hypotheses based on their goodness of fit. These functional form models were then used to parameterize a simple simulation model of population growth. Our data support non-additive density dependence and presents an alternate hypothesis to additive density dependence, self-thinning and Allee effects in larval amphibians. We posit that ringed salamander larvae may be under selective pressure for tolerance to high density and increased efficiency in resource utilization. Additionally, we demonstrate that models of population dynamics are sensitive to assumptions of the functional form of density dependence.

  1. Getting out alive: how predators affect the decision to metamorphose.

    PubMed

    Relyea, Rick A

    2007-06-01

    Metamorphosis has intrigued biologists for a long time as an extreme form of complex life cycles that are ubiquitous in animals. While investigated from a variety of perspectives, the ecological focus has been on identifying and understanding the ecological factors that affect an individual's decision on when, and at what size, to metamorphose. Predation is a major factor that affects metamorphic decisions and a recent review by Benard (Annu Rev Ecol Evol Syst 35:651-673, 2004)) documented how predator cues induce metamorphic changes relative to model predictions. Importantly, however, real predators affect larval prey via several mechanisms beyond simple induction. In this paper, I contrast the leading models of metamorphosis, provide an overview of the multiple ways that predators can directly and indirectly affect larval growth and development (via induction, thinning, and selection), and identify how each process should affect the time to and size at metamorphosis. With this mechanistic foundation established, I then turn to the well-studied model system of larval amphibians to synthesize studies on: (1) caged predators (which cause only induction), and (2) lethal predators (which cause induction, thinning, and selection). Among the caged-predator studies, the chemical cues emitted by predators rarely induce a smaller size at metamorphosis or a shorter time to metamorphosis, which is in direct contrast to theoretical predictions but in agreement with Benard's (Annu Rev Ecol Evol Syst 35:651-673, 2004) review based on a considerably smaller dataset. Among the lethal-predator studies, there is a diversity of outcomes depending upon the relative importance of induction versus thinning with the relative importance of the two processes appearing to change with larval density. Finally, I review the persistent effects of larval predators after metamorphosis including both phenotypic and fitness effects. At the end, I outline a number of future directions to allow

  2. Various light source treatments affect body and skeletal muscle growth by affecting skeletal muscle satellite cell proliferation in broilers.

    PubMed

    Halevy, O; Biran, I; Rozenboim, I

    1998-06-01

    In this study we addressed the effect of various monochromatic light treatments on muscle growth and satellite cell proliferation in broilers (Gallus domesticus). Broilers were reared under green (560 nm), blue (480 nm) and red (660 nm) monochromatic lights and white light as a control from day one until 35 days of age. At five days of age, satellite cells were prepared from the experimental chicks. The number of satellite cells per gram of breast muscle and total number of satellite cells derived from the experimental broilers was substantially higher in the groups reared under green and blue light, compared to the red and white light groups. Growth hormone receptor gene expression was also higher in the former groups. High correlation was found between the breast muscle weight observed on day 35 and the number of satellite cells per gram of breast muscle (r = 0.915) and total number of satellite cells (r = 0.833), derived from the experimental chicks as early as five days of age. In addition, the protein/DNA ratio found in breast muscle at 35 days of age was significantly lower in chicks that were reared under green and blue lights. The lowest ratio which was found in the green group and was twice as low as in the control group, indicates the highest number of nuclei in the former group. As satellite cells are the only source of additional nuclei in skeletal muscles of postnatal animals, our results suggest that the higher muscle weight found in the green and blue light groups was due to increased satellite cell proliferation during the first days of age.

  3. Individual heterogeneity and offspring sex affect the growth-reproduction trade-off in a mammal with indeterminate growth.

    PubMed

    Gélin, Uriel; Wilson, Michelle E; Cripps, Jemma; Coulson, Graeme; Festa-Bianchet, Marco

    2016-04-01

    Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.

  4. Experimental studies on the larval development of the shrimps Crangon crangon and C. allmanni

    NASA Astrophysics Data System (ADS)

    Criales, M. M.; Anger, K.

    1986-09-01

    Larvae of the shrimps Crangon crangon L. and C. allmanni Kinahan were reared in the laboratory from hatching through metamorphosis. Effects of rearing methods (larval density, application of streptomycin, food) and of salinity on larval development were tested only in C. crangon, influence of temperature was studied in both species. Best results were obtained when larvae were reared individually, with a mixture of Artemia sp. and the rotifer Brachionus plicatilis as food. Streptomycin had partly negative effects and was thus not adopted for standard rearing techniques. All factors tested in this study influenced not only the rates of larval survival and moulting, but also morphogenesis. In both species, in particular in C. crangon, a high degree of variability in larval morphology and in developmental pathways was observed. Unsuitable conditions, e.g. crowding in mass culture, application of antibiotics, unsuitable food (rotifers, phytoplankton), extreme temperatures and salinities, tend to increase the number of larval instars and of morphological forms. The frequency of moulting is controlled mainly by temperature. Regression equations describing the relations between the durations of larval instars and temperature are given for both Crangon species. The number of moults is a linear function of larval age and a power function of temperature. There is high variation in growth (measured as carapace length), moulting frequency, morphogenesis, and survival among hatches originating from different females. The interrelations between these different measures of larval development in shrimps and prawns are discussed.

  5. Ice cover affects the growth of a stream-dwelling fish.

    PubMed

    Watz, Johan; Bergman, Eva; Piccolo, John J; Greenberg, Larry

    2016-05-01

    Protection provided by shelter is important for survival and affects the time and energy budgets of animals. It has been suggested that in fresh waters at high latitudes and altitudes, surface ice during winter functions as overhead cover for fish, reducing the predation risk from terrestrial piscivores. We simulated ice cover by suspending plastic sheeting over five 30-m-long stream sections in a boreal forest stream and examined its effects on the growth and habitat use of brown trout (Salmo trutta) during winter. Trout that spent the winter under the artificial ice cover grew more than those in the control (uncovered) sections. Moreover, tracking of trout tagged with passive integrated transponders showed that in the absence of the artificial ice cover, habitat use during the day was restricted to the stream edges, often under undercut banks, whereas under the simulated ice cover condition, trout used the entire width of the stream. These results indicate that the presence of surface ice cover may improve the energetic status and broaden habitat use of stream fish during winter. It is therefore likely that reductions in the duration and extent of ice cover due to climate change will alter time and energy budgets, with potentially negative effects on fish production.

  6. Histopathology of Growth Anomaly Affecting the Coral, Montipora capitata: Implications on Biological Functions and Population Viability

    PubMed Central

    Burns, John H. R.; Takabayashi, Misaki

    2011-01-01

    Growth anomalies (GAs) affect the coral, Montipora capitata, at Wai'ōpae, southeast Hawai'i Island. Our histopathological analysis of this disease revealed that the GA tissue undergoes changes which compromise anatomical machinery for biological functions such as defense, feeding, digestion, and reproduction. GA tissue exhibited significant reductions in density of ova (66.1–93.7%), symbiotic dinoflagellates (38.8–67.5%), mesenterial filaments (11.2–29.0%), and nematocytes (28.8–46.0%). Hyperplasia of the basal body wall but no abnormal levels of necrosis and algal or fungal invasion was found in GA tissue. Skeletal density along the basal body wall was significantly reduced in GAs compared to healthy or unaffected sections. The reductions in density of the above histological features in GA tissue were collated with disease severity data to quantify the impact of this disease at the colony and population level. Resulting calculations showed this disease reduces the fecundity of M. capitata colonies at Wai'ōpae by 0.7–49.6%, depending on GA severity, and the overall population fecundity by 2.41±0.29%. In sum, GA in this M. capitata population reduces the coral's critical biological functions and increases susceptibility to erosion, clearly defining itself as a disease and an ecological threat. PMID:22205976

  7. Bioprospecting for microbial products that affect ice crystal formation and growth.

    PubMed

    Christner, Brent C

    2010-01-01

    At low temperatures, some organisms produce proteins that affect ice nucleation, ice crystal structure, and/or the process of recrystallization. Based on their ice-interacting properties, these proteins provide an advantage to species that commonly experience the phase change from water to ice or rarely experience temperatures above the melting point. Substances that bind, inhibit or enhance, and control the size, shape, and growth of ice crystals could offer new possibilities for a number of agricultural, biomedical, and industrial applications. Since their discovery more than 40 years ago, ice nucleating and structuring proteins have been used in cryopreservation, frozen food preparation, transgenic crops, and even weather modification. Ice-interacting proteins have demonstrated commercial value in industrial applications; however, the full biotechnological potential of these products has yet to be fully realized. The Earth's cold biosphere contains an almost endless diversity of microorganisms to bioprospect for microbial compounds with novel ice-interacting properties. Microorganisms are the most appropriate biochemical factories to cost effectively produce ice nucleating and structuring proteins on large commercial scales.

  8. Mutation of AREA affects growth, sporulation, nitrogen regulation, and pathogenicity in Colletotrichum gloeosporioides.

    PubMed

    Bi, Fangcheng; Ment, Dana; Luria, Neta; Meng, Xiangchun; Prusky, Dov

    2017-02-01

    The GATA transcription factor AreA is a global nitrogen regulator that restricts the utilization of complex and poor nitrogen sources in the presence of good nitrogen sources in microorganisms. In this study, we report the biological function of an AreA homolog (the CgareA gene) in the fruit postharvest pathogen Colletotrichum gloeosporioides. Targeted gene deletion mutants of areA exhibited significant reductions in vegetative growth, increases in conidia production, and slight decreases in conidial germination rates. Quantitative RT-PCR (qRT-PCR) analysis revealed that the expression of AreA was highly induced under nitrogen-limiting conditions. Moreover, compared to wild-type and complemented strains, nitrogen metabolism-related genes were misregulated in ΔareA mutant strains. Pathogenicity assays indicated that the virulence of ΔareA mutant strains were affected by the nitrogen content, but not the carbon content, of fruit hosts. Taken together, our results indicate that CgareA plays a critical role in fungal development, conidia production, regulation of nitrogen metabolism and virulence in Colletotrichum gloeosporioides.

  9. Paternal MHC expression on mouse trophoblast affects uterine vascularization and fetal growth.

    PubMed

    Madeja, Zofia; Yadi, Hakim; Apps, Richard; Boulenouar, Selma; Roper, Stephen J; Gardner, Lucy; Moffett, Ashley; Colucci, Francesco; Hemberger, Myriam

    2011-03-08

    The mammalian fetus represents a semiallograft within the maternal uterus yet is not rejected. This situation is particularly pronounced in species with a hemochorial type of placentation, such as humans and rodents, where maternal tissues and blood are in direct contact with fetal trophoblast and thus potentially with paternal antigens. The main polymorphic antigens responsible for graft rejection are MHC antigens. In humans the trophoblast cells invading into the decidua have a unique pattern of MHC class I expression characterized by both classical (HLA-C) and nonclassical (HLA-G and HLA-E) molecules. Whether such an unusual MHC repertoire on the surface of trophoblast is a conserved feature between species with hemochorial placentation has not been resolved. Here we demonstrate, using a range of methods, that C57BL/6 mouse trophoblast predominantly expresses only one MHC class I antigen, H2-K, at the cell surface of giant cells but lacks expression of nonclassical MHC molecules. Antigenic disparity between parental MHCs affects trophoblast-induced transformation of the uterine vasculature and, consequently, placental and fetal gowth. Maternal uterine blood vessels were more dilated, allowing for increased blood supply, in certain combinations of maternal and paternal MHC haplotypes, and these allogeneic fetuses and placentas were heavier at term compared with syngeneic controls. Thus, maternal-fetal immune interactions are instrumental to optimize reproductive success. This cross-talk has important implications for human disorders of pregnancy, such as preeclampsia and fetal growth restriction.

  10. Bovine growth hormone gene polymorphism affects stress response in Japanese Black cattle.

    PubMed

    Tachi, Noriko; Tanaka, Sigefumi; Ardiyanti, Astrid; Katoh, Kazuo; Sato, Shusuke

    2014-06-01

    We investigate the associations between growth hormone (GH) gene polymorphism and behavioral and physiological responses to stressors and learning ability in Japanese Black cattle. Flight distance test was conducted in the first experiment. Steers with haplotype C of GH gene polymorphism avoided human approaches at a significantly greater distance than ones without haplotype C (C: 1.9 ± 0.9, non-C: 1.0 ± 0.2 m, P < 0.05). An open-field test was conducted in the second experiment. Behavioral responses did not differ significantly between steers with and without haplotype C. Increases of heart rates to dropping of iron pipes was significantly higher in steers with haplotype C (C:161.7 ± 21.8, non-C:130.7 ± 31.3%, P < 0.05). Despite basal serum concentrations not being different between steers with and without haplotype C, serum cortisol in blood sampling immediately after severe confinement in a race tended to be higher in steers with haplotype C (P = 0.1). The maze test was conducted as the third experiment. There was no difference in performance in the maze test between steers with and without haplotype C. It is concluded that genetic polymorphism of GH may affect stress responses through GH concentration in steers.

  11. Environmental factors limiting fertilisation and larval success in corals

    NASA Astrophysics Data System (ADS)

    Woods, Rachael M.; Baird, Andrew H.; Mizerek, Toni L.; Madin, Joshua S.

    2016-12-01

    Events in the early life history of reef-building corals, including fertilisation and larval survival, are susceptible to changes in the chemical and physical properties of sea water. Quantifying how changes in water quality affect these events is therefore important for understanding and predicting population establishment in novel and changing environments. A review of the literature identified that levels of salinity, temperature, pH, suspended sediment, nutrients and heavy metals affect coral early life-history stages to various degrees. In this study, we combined published experimental data to determine the relative importance of sea water properties for coral fertilisation success and larval survivorship. Of the water properties manipulated in experiments, fertilisation success was most sensitive to suspended sediment, copper, salinity, phosphate and ammonium. Larval survivorship was sensitive to copper, lead and salinity. A combined model was developed that estimated the joint probability of both fertilisation and larval survivorship in sea water with different chemical and physical properties. We demonstrated the combined model using water samples from Sydney and Lizard Island in Australia to estimate the likelihood of larvae surviving through both stages of development to settlement competency. Our combined model could be used to recommend targets for water quality in coastal waterways as well as to predict the potential for species to expand their geographical ranges in response to climate change.

  12. Increasing water stress negatively affects pear fruit growth by reducing first its xylem and then its phloem inflow.

    PubMed

    Morandi, Brunella; Losciale, Pasquale; Manfrini, Luigi; Zibordi, Marco; Anconelli, Stefano; Galli, Fabio; Pierpaoli, Emanuele; Corelli Grappadelli, Luca

    2014-10-15

    Drought stress negatively affects many physiological parameters and determines lower yields and fruit size. This paper investigates on the effects of prolonged water restriction on leaf gas exchanges, water relations and fruit growth on a 24-h time-scale in order to understand how different physiological processes interact to each other to face increasing drought stress and affect pear productive performances during the season. The diurnal patterns of tree water relations, leaf gas exchanges, fruit growth, fruit vascular and transpiration flows were monitored at about 50, 95 and 145 days after full bloom (DAFB) on pear trees of the cv. Abbé Fétel, subjected to two irrigation regimes, corresponding to a water restitution of 100% and 25% of the estimated Etc, respectively. Drought stress progressively increased during the season due to lower soil tensions and higher daily vapour pressure deficits (VPDs). Stem water potential was the first parameter to be negatively affected by stress and determined the simultaneous reduction of fruit xylem flow, which at 95 DAFB was reflected by a decrease in fruit daily growth. Leaf photosynthesis was reduced only from 95 DAFB on, but was not immediately reflected by a decrease in fruit phloem flow, which instead was reduced only at 145 DAFB. This work shows how water stress negatively affects pear fruit growth by reducing first its xylem and then its phloem inflow. This determines a progressive increase in the phloem relative contribution to growth, which lead to the typical higher dry matter percentages of stressed fruit.

  13. Correlated Evolution between Mode of Larval Development and Habitat in Muricid Gastropods

    PubMed Central

    Pappalardo, Paula; Rodríguez-Serrano, Enrique; Fernández, Miriam

    2014-01-01

    Abstract Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule), which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding) development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in muricids

  14. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    PubMed

    Pappalardo, Paula; Rodríguez-Serrano, Enrique; Fernández, Miriam

    2014-01-01

    Larval modes of development affect evolutionary processes and influence the distribution of marine invertebrates in the ocean. The decrease in pelagic development toward higher latitudes is one of the patterns of distribution most frequently discussed in marine organisms (Thorson's rule), which has been related to increased larval mortality associated with long pelagic durations in colder waters. However, the type of substrate occupied by adults has been suggested to influence the generality of the latitudinal patterns in larval development. To help understand how the environment affects the evolution of larval types we evaluated the association between larval development and habitat using gastropods of the Muricidae family as a model group. To achieve this goal, we collected information on latitudinal distribution, sea water temperature, larval development and type of substrate occupied by adults. We constructed a molecular phylogeny for 45 species of muricids to estimate the ancestral character states and to assess the relationship between traits using comparative methods in a Bayesian framework. Our results showed high probability for a common ancestor of the muricids with nonpelagic (and nonfeeding) development, that lived in hard bottoms and cold temperatures. From this ancestor, a pelagic feeding larva evolved three times, and some species shifted to warmer temperatures or sand bottoms. The evolution of larval development was not independent of habitat; the most probable evolutionary route reconstructed in the analysis of correlated evolution showed that type of larval development may change in soft bottoms but in hard bottoms this change is highly unlikely. Lower sea water temperatures were associated with nonpelagic modes of development, supporting Thorson's rule. We show how environmental pressures can favor a particular mode of larval development or transitions between larval modes and discuss the reacquisition of feeding larva in muricids gastropods.

  15. The effect of larval density on adult demographic traits in Ambystoma opacum

    SciTech Connect

    Scott, D.E. )

    1994-07-01

    Factors that affect traits of aquatic larvae of amphibians may have long-lasting effects on terrestrial juveniles and adults. I manipulated larval densities of marbled salamanders, Ambystoma opacum, in large-scale field enclosures during 2 yr, released the juveniles that metamorphosed from these enclosures, and tested for effects on adults that returned to the pond during 6-7 subsequent breeding seasons. Individuals from low larval density treatments tended to have greater lipid stores at metamorphosis than those from high densities and survived longer in a laboratory inanition study. In the field, individuals that experienced low larval density returned for their first reproductive bout as larger adults than those from high-density treatments. For 5-yr-old females released in 1986, low larval density was linked to greater clutch size; clutch size in 4-yr-old animals from the 1987 cohort did not differ between larval treatment groups. Larval density also influenced age at first reproduction, as animals rared at low densities returned to breed at younger ages. Averaged across both cohorts, the proportion of animals that returned to breed at least once was 21% for low-density groups compared to 6% for the high density groups. The larval environment exerted a strong influence on postmetamorphic traits, and thus larval density likely plays an important role of population regulation in both the aquatic and terrestrial phase of the life cycle. 81 refs., 4 figs., 6 tabs.

  16. Biological Strategies of Dermestes maculatus DeGeer (Coleoptera: Dermestidae) at Larval Stages in Different Temperatures.

    PubMed

    Zanetti, N I; Visciarelli, E C; Centeno, N D

    2016-12-01

    The intraspecific variation in larval instars is a widely distributed phenomenon amongst holometabolous insects. Several factors can affect the number of instars, such as temperature, humidity, and density. Only a few references could be found in the literature because the invariability in the number of larval instars is considered normal, and the issue has raised little to no interest. Despite this, no study to date has intended to assess or focus on the larval development. Here, we analyzed the effect of different rearing temperature on the larval stage of Dermestes maculatus DeGeer (Coleoptera: Dermestidae). The results indicated that at all temperatures, L5 represented a decisive point for individuals as well as the other later larval instars, because the next step to follow was to pupate or molt to the next larval instar. Furthermore, there were mainly two populations, L5 and L6, although in different proportions according to temperature. We also found that at a greater number of instars, the larval development at all temperatures lasted longer. Moreover, the exponential model was the best adjustment in the developmental time of all populations as well as for the accumulated developmental time of L1-L4. Thus, we conclude that random factors such as genetics could probably cause interspecific variability in D. maculatus larval development.

  17. Endogenous abscisic acid promotes hypocotyl growth and affects endoreduplication during dark-induced growth in tomato (Solanum lycopersicum L.).

    PubMed

    Humplík, Jan F; Bergougnoux, Véronique; Jandová, Michaela; Šimura, Jan; Pěnčík, Aleš; Tomanec, Ondřej; Rolčík, Jakub; Novák, Ondřej; Fellner, Martin

    2015-01-01

    Dark-induced growth (skotomorphogenesis) is primarily characterized by rapid elongation of the hypocotyl. We have studied the role of abscisic acid (ABA) during the development of young tomato (Solanum lycopersicum L.) seedlings. We observed that ABA deficiency caused a reduction in hypocotyl growth at the level of cell elongation and that the growth in ABA-deficient plants could be improved by treatment with exogenous ABA, through which the plants show a concentration dependent response. In addition, ABA accumulated in dark-grown tomato seedlings that grew rapidly, whereas seedlings grown under blue light exhibited low growth rates and accumulated less ABA. We demonstrated that ABA promotes DNA endoreduplication by enhancing the expression of the genes encoding inhibitors of cyclin-dependent kinases SlKRP1 and SlKRP3 and by reducing cytokinin levels. These data were supported by the expression analysis of the genes which encode enzymes involved in ABA and CK metabolism. Our results show that ABA is essential for the process of hypocotyl elongation and that appropriate control of the endogenous level of ABA is required in order to drive the growth of etiolated seedlings.

  18. Larval and nurse worker control of developmental plasticity and the evolution of honey bee queen-worker dimorphism

    PubMed Central

    Linksvayer, Timothy A.; Kaftanoglu, Osman; Akyol, Ethem; Blatch, Sydella; Amdam, Gro V.; Page, Robert E.

    2011-01-01

    Social evolution in honey bees has produced strong queen-worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental program includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body size and ovary size for two pairs of honey bee lineages that show similar differences in worker body-ovary size allometry but have diverged over different evolutionary time scales. Our results indicate: that the lineages have diverged for both nurse and larval developmental components, that rapid changes in worker body-ovary allometry may disrupt queen development, and that queen-worker dimorphism arises mainly from discrete nurse-provided nutritional environments, not from a developmental switch that converts variable nutritional environments into discrete phenotypes. Both larval and nurse components have likely contributed to the evolution of queen-worker dimorphism. PMID:21696476

  19. Does seawater acidification affect survival, growth and shell integrity in bivalve juveniles?

    PubMed

    Bressan, M; Chinellato, A; Munari, M; Matozzo, V; Manci, A; Marčeta, T; Finos, L; Moro, I; Pastore, P; Badocco, D; Marin, M G

    2014-08-01

    Anthropogenic emissions of carbon dioxide are leading to decreases in pH and changes in the carbonate chemistry of seawater. Ocean acidification may negatively affect the ability of marine organisms to produce calcareous structures while also influencing their physiological responses and growth. The aim of this study was to evaluate the effects of reduced pH on the survival, growth and shell integrity of juveniles of two marine bivalves from the Northern Adriatic sea: the Mediterranean mussel Mytilus galloprovincialis and the striped venus clam Chamelea gallina. An outdoor flow-through plant was set up and two pH levels (natural seawater pH as a control, pH 7.4 as the treatment) were tested in long-term experiments. Mortality was low throughout the first experiment for both mussels and clams, but a significant increase, which was sensibly higher in clams, was observed at the end of the experiment (6 months). Significant decreases in the live weight (-26%) and, surprisingly, in the shell length (-5%) were observed in treated clams, but not in mussels. In the controls of both species, no shell damage was ever recorded; in the treated mussels and clams, damage proceeded via different modes and to different extents. The severity of shell injuries was maximal in the mussels after just 3 months of exposure to a reduced pH, whereas it progressively increased in clams until the end of the experiment. In shells of both species, the damaged area increased throughout the experiment, peaking at 35% in mussels and 11% in clams. The shell thickness of the treated and control animals significantly decreased after 3 months in clams and after 6 months in mussels. In the second experiment (3 months), only juvenile mussels were exposed to a reduced pH. After 3 months, the mussels at a natural pH level or pH 7.4 did not differ in their survival, shell length or live weight. Conversely, shell damage was clearly visible in the treated mussels from the 1st month onward. Monitoring the

  20. Intranasal nerve growth factor bypasses the blood-brain barrier and affects spinal cord neurons in spinal cord injury

    PubMed Central

    Aloe, Luigi; Bianchi, Patrizia; De Bellis, Alberto; Soligo, Marzia; Rocco, Maria Luisa

    2014-01-01

    The purpose of this work was to investigate whether, by intranasal administration, the nerve growth factor bypasses the blood-brain barrier and turns over the spinal cord neurons and if such therapeutic approach could be of value in the treatment of spinal cord injury. Adult Sprague-Dawley rats with intact and injured spinal cord received daily intranasal nerve growth factor administration in both nostrils for 1 day or for 3 consecutive weeks. We found an increased content of nerve growth factor and enhanced expression of nerve growth factor receptor in the spinal cord 24 hours after a single intranasal administration of nerve growth factor in healthy rats, while daily treatment for 3 weeks in a model of spinal cord injury improved the deficits in locomotor behaviour and increased spinal content of both nerve growth factor and nerve growth factor receptors. These outcomes suggest that the intranasal nerve growth factor bypasses blood-brain barrier and affects spinal cord neurons in spinal cord injury. They also suggest exploiting the possible therapeutic role of intranasally delivered nerve growth factor for the neuroprotection of damaged spinal nerve cells. PMID:25206755

  1. Embryonic zebrafish neuronal growth is not affected by an applied electric field in vitro.

    PubMed

    Cormie, Peter; Robinson, Kenneth R

    2007-01-10

    Naturally occurring electric fields (EFs) have been implicated in cell guidance during embryonic development and adult wound healing. Embryonic Xenopus laevis neurons sprout preferentially towards the cathode, turn towards the cathode, and migrate faster towards the cathode in the presence of an external EF in vitro. A recent Phase 1 clinical trial has investigated the effects of oscillating EFs on human spinal cord regeneration. The purpose of this study was to investigate whether embryonic zebrafish neurons respond to an applied EF, and thus extend this research into another vertebrate system. Neural tubes of zebrafish embryos (16-17 somites) were dissected and dissociated neuroblasts were plated onto laminin-coated glass. A 100 mV/mm EF was applied to cell cultures for 4 or 20 h and the responses of neurons to the applied EFs were investigated. After 4h in an EF neurites were significantly shorter than control neurites. No other statistically significant effects were observed. After 20 h, control and EF-exposed neurites were no different in length. No length difference was seen between cathodally- and anodally-sprouted neurites. Application of an EF did not affect the average number of neurons in a chamber. Growth cones did not migrate preferentially towards either pole of the EF and no asymmetry was seen in neurite sprout sites. We conclude that zebrafish neurons do not respond to a 100 mV/mm applied EF in vitro. This suggests that neurons of other vertebrate species may not respond to applied EFs in the same ways as Xenopus laevis neurons.

  2. Evaluation of five antibiotics on larval gut bacterial diversity of Plutella xylostella (Lepidoptera: Plutellidae).

    PubMed

    Lin, Xiao-Li; Kang, Zhi-Wei; Pan, Qin-Jian; Liu, Tong-Xian

    2015-10-01

    Larvae of the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), have rich microbial communities inhabiting the gut, and these bacteria contribute to the fitness of the pest. In this study we evaluated the effects of five antibiotics (rifampicin, ampicillin, tetracycline, streptomycin sulfate and chloramphenicol) on the gut bacterial diversity of P. xylostella larvae. We screened five different concentrations for each antibiotic in a leaf disc assay, and found that rifampicin and streptomycin sulfate at 3 mg/mL significantly reduced the diversity of the bacterial community, and some bacterial species could be rapidly eliminated. The number of gut bacteria in the rifampicin group and streptomycin sulfate group decreased more rapidly than the others. With the increase of antibiotic concentration, the removal efficiency was improved, whereas toxic effects became more apparent. All antibiotics reduced larval growth and development, and eventually caused high mortality, malformation of the prepupae, and hindered pupation and adult emergence. Among the five antibiotics, tetracycline was the most toxic and streptomycin sulfate was a relatively mild one. Some dominant bacteria were not affected by feeding antibiotics alone. Denaturing gradient gel electrophoresis graph showed that the most abundant and diverse bacteria in P. xylostella larval gut appeared in the cabbage feeding group, and diet change and antibiotics intake influenced gut flora abundance. Species diversity was significantly reduced in the artificial diet and antibiotics treatment groups. After feeding on the artificial diet with rifampicin, streptomycin sulfate and their mixture for 10 days, larval gut bacteria could not be completely removed as detected with the agarose gel electrophoresis method.

  3. The timing of "catch-up growth" affects metabolism and appetite regulation in male rats born with intrauterine growth restriction.

    PubMed

    Coupé, Bérengère; Grit, Isabelle; Darmaun, Dominique; Parnet, Patricia

    2009-09-01

    Epidemiological studies demonstrated a relationship between low birth weight mainly caused by intrauterine growth restriction (IUGR) and adult metabolic disorders. The concept of metabolic programming centers on the idea that nutritional and hormonal status during the key period of development determines the long-term control of energy balance by programming future feeding behavior and energy expenditure. The present study examined the consequence of early or late "catch-up growth" after IUGR on feeding behavior and metabolic cues of male offspring of rat dams exposed to protein restriction during gestation and/or lactation. Our results suggest that early catch-up growth may be favorable for fasting metabolic parameters at weaning, as no differences were observed on plasma leptin, triglyceride, glucose, and insulin levels compared with controls. In contrast, if pups remained malnourished until weaning, low insulin concentration was detected and was accompanied by hyperphagia associated with a large increase in hypothalamic NPY and AgRP mRNA expression. At adult age, on a regular chow diet, only the meal structure was modified by fetal programming. The two IUGR groups demonstrated a reduced meal duration that enhanced the speed of food ingestion and consequently increased the rest period associated to the satiety state without changes in the hypothalamic expression of appetite neuropeptides. Our findings demonstrate that in IUGR, regardless of postnatal growth magnitude, metabolic programming occurred in utero and was responsible for both feeding behavior alteration and postprandial higher insulin level in adults. Additionally, catch-up growth immediately after early malnutrition could be a key point for the programming of postprandial hyperleptinemia.

  4. Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss) The cost and scarcity of key ingredients for aquaculture feed formulation call for a wise use of resources, especially dietary proteins and energy. For years t...

  5. Stretch-activated cation channel from larval bullfrog skin

    PubMed Central

    Hillyard, Stanley D.; Willumsen, Niels J.; Marrero, Mario B.

    2010-01-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (−1 kPa to −4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed a variable pattern of opening and closing with continuing suction. Current–voltage plots demonstrated linear or inward rectification and single channel conductances of 44–56 pS with NaCl or KCl Ringer's solution as the pipette solution, and a reversal potential (−Vp) of 20–40 mV. The conductance was markedly reduced with N-methyl-D-glucamide (NMDG)-Cl Ringer's solution in the pipette. Neither amiloride nor ATP, which are known to stimulate an apical cation channel in Ussing chamber preparations of larval frog skin, produced channel activation nor did these compounds affect the response to suction. Stretch activation was not affected by varying the pipette concentrations of Ca2+ between 0 mmol l−1 and 4 mmol l−1 or by varying pH between 6.8 and 8.0. However, conductance was reduced with 4 mmol l−1 Ca2+. Western blot analysis of membrane homogenates from larval bullfrog and larval toad skin identified proteins that were immunoreactive with mammalian TRPC1 and TRPC5 (TRPC, canonical transient receptor potential channel) antibodies while homogenates of skin from newly metamorphosed bullfrogs were positive for TRPC1 and TRPC3/6/7 antibodies. The electrophysiological response of larval bullfrog skin resembles that of a stretch-activated cation channel characterized in Xenopus oocytes and proposed to be TRPC1. These results indicate this channel persists in all life stages of anurans and that TRP isoforms may be important for sensory functions of their skin. PMID:20435829

  6. Sub-toxic nicotine concentrations affect extracellular matrix and growth factor signaling gene expressions in human osteoblasts.

    PubMed

    Marinucci, Lorella; Bodo, Maria; Balloni, Stefania; Locci, Paola; Baroni, Tiziano

    2014-12-01

    Exposure to nicotine and other compounds contained in cigarette smoking affects human health. This study examined the effects of exposure to a single or multiple sub-toxic nicotine concentrations on human osteoblasts. Cell growth and expression of genes involved in bone differentiation, extracellular matrix (ECM) metabolism, and growth factor signaling pathways were investigated in nicotine-treated cells compared to untreated cells. Depending on osteoblast concentration and maturation stages, nicotine differently regulated cell growth. Real-time PCR showed regulated expressions of genes expressed by nicotine-treated osteoblasts compared to untreated cells. Among ECM genes, type I collagen was down-regulated and osteonectin was up-regulated in nicotine-treated osteoblasts; similarly, fibroblast growth factor-1 (FGF1) and fibroblast growth factor-2 (FGF2), two members of FGF signaling system, were discordantly modulated; genes involved in osteoblast maturation and differentiation such as alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), and bone sialoprotein (BSP) were over-expressed after drug treatment. Our results show a positive association between nicotine exposure and osteoblast phenotype and illustrate for the first time a mechanism whereby acute or chronic exposure to sub-toxic nicotine concentrations may affect bone formation through the impairment of growth factor signaling system and ECM metabolism.

  7. Swimming behavior of larval Medaka fish under microgravity

    NASA Astrophysics Data System (ADS)

    Furukawa, R.; Ijiri, K.

    Fish exhibit looping and rolling behaviors when subjected to short periods of microgravity during parabolic flight. Strain-differences in the behavioral response of adult Medaka fish ( Oryzias latipes) were reported previously, however, there have been few studies of larval fish behavior under microgravity. In the present study, we investigated whether microgravity affects the swimming behavior of larvae at various ages (0 to 20 days after hatching), using different strains: HNI-II, HO5, ha strain, and variety of different strains (variety). The preliminary experiments were done in the ground laboratory: the development of eyesight was examined using optokinetic response for the different strains. The visual acuity of larvae improved drastically during 20 days after hatching. Strain differences of response were noted for the development of their visual acuity. In microgravity, the results were significantly different from those of adult Medaka. The larval fish appeared to maintain their orientation, except that a few of them exhibited looping and rolling behavior. Further, most larvae swam normally with their backs turning toward the light source (dorsal light response, DLR), and the rest of them stayed with their abdomen touching the surface of the container (ventral substrate response, VSR). For larval stages, strain-differences and age-differences in behavior were observed, but less pronounced than with adult fish under microgravity. Our observations suggest that adaptability of larval fish to the gravitational change and the mechanism of their postural control in microgravity are more variable than in adult fish.

  8. Unlikely Remedy: Fungicide Clears Infection from Pathogenic Fungus in Larval Southern Leopard Frogs (Lithobates sphenocephalus)

    PubMed Central

    Hanlon, Shane M.; Kerby, Jacob L.; Parris, Matthew J.

    2012-01-01

    Amphibians are often exposed to a wide variety of perturbations. Two of these, pesticides and pathogens, are linked to declines in both amphibian health and population viability. Many studies have examined the separate effects of such perturbations; however, few have examined the effects of simultaneous exposure of both to amphibians. In this study, we exposed larval southern leopard frog tadpoles (Lithobates sphenocephalus) to the chytrid fungus Batrachochytrium dendrobatidis and the fungicide thiophanate-methyl (TM) at 0.6 mg/L under laboratory conditions. The experiment was continued until all larvae completed metamorphosis or died. Overall, TM facilitated increases in tadpole mass and length. Additionally, individuals exposed to both TM and Bd were heavier and larger, compared to all other treatments. TM also cleared Bd in infected larvae. We conclude that TM affects larval anurans to facilitate growth and development while clearing Bd infection. Our findings highlight the need for more research into multiple perturbations, specifically pesticides and disease, to further promote amphibian heath. PMID:22912890

  9. Parental effects on the larval performance of a tapeworm in its copepod first host.

    PubMed

    Benesh, D P

    2013-08-01

    Parents can influence the phenotype of their offspring through various mechanisms, besides the direct effect of heredity. Such parental effects are little explored in parasitic organisms, perhaps because in many parasites, per capita investment into offspring is low. I investigated whether parental identity, beyond direct genetic effects, could explain variation in the performance of the tapeworm Schistocephalus solidus in its first intermediate host, a copepod. I first determined that two breeding worms could be separated from one another after ~48 h of in vitro incubation and that the isolated worms continued producing outcrossed eggs, that is, rates self-fertilization did not increase after separation. Thus, from a breeding pair, two sets of genetically comparable eggs can be collected that have unambiguous parental identities. In an infection experiment, I found that the development of larval worms tended to vary between the two parental worms within breeding pairs, but infection success and growth rate in copepods did not. Accounting for this parental effect decreased the estimated heritability for development by nearly half. These results suggest that larval performance is not simply a function of a worm's genotype; who mothered or fathered an offspring can also affect offspring fitness, contradicting the perhaps naïve idea that parasites simply produce large quantities of uniformly low-quality offspring.

  10. Larval connectivity of pearl oyster through biophysical modelling; evidence of food limitation and broodstock effect

    NASA Astrophysics Data System (ADS)

    Thomas, Yoann; Dumas, Franck; Andréfouët, Serge

    2016-12-01

    The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia atoll lagoons. This aquaculture relies on spat collection, a process that experiences spatial and temporal variability and needs to be optimized by understanding which factors influence recruitment. Here, we investigate the sensitivity of P. margaritifera larval dispersal to both physical and biological factors in the lagoon of Ahe atoll. Coupling a validated 3D larval dispersal model, a bioenergetics larval growth model following the Dynamic Energy Budget (DEB) theory, and a population dynamics model, the variability of lagoon-scale connectivity patterns and recruitment potential is investigated. The relative contribution of reared and wild broodstock to the lagoon-scale recruitment potential is also investigated. Sensitivity analyses pointed out the major effect of the broodstock population structure as well as the sensitivity to larval mortality rate and inter-individual growth variability to larval supply and to the subsequent settlement potential. The application of the growth model clarifies how trophic conditions determine the larval supply and connectivity patterns. These results provide new cues to understand the dynamics of bottom-dwelling populations in atoll lagoons, their recruitment, and discuss how to take advantage of these findings and numerical models for pearl oyster management.

  11. Does solar radiation affect the growth of tomato seeds relative to their environment?

    NASA Technical Reports Server (NTRS)

    Holzer, Kristi

    1995-01-01

    The purpose of this experiment is to sequentially study and analyze the data collected from the germination and growth of irradiated Rutgers Supreme tomato seeds to adult producing plants. This experiment will not use irradiated seeds as a control as I plan to note growth in artificial verses natural environment as the basic experiment.

  12. Dissolved oxygen levels affect dimorphic growth by the entomopathogenic fungus Isaria fumosorosea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The entomopathogenic fungus Isaria fumosorosea is capable of dimorphic growth (hyphal or yeast-like) in submerged culture. In shake flask studies, we evaluated the impact of aeration on the mode of growth of I. fumosorosea. Using 250 mL baffled Erlenmeyer flasks, culture volumes of 50, 100, 150, a...

  13. Does solar radiation affect the growth of tomato seeds relative to their environment?

    SciTech Connect

    Holzer, K.

    1995-09-01

    The purpose of this experiment is to sequentially study and analyze the data collected from the germination and growth of irradiated Rutgers Supreme tomato seeds to adult producing plants. This experiment will not use irradiated seeds as a control as the authors plans to note growth in artificial verses natural environment as the basic experiment.

  14. Survey of naturally and conventionally cured commercial frankfurters, ham, and bacon for physio-chemical characteristics that affect bacterial growth.

    PubMed

    Sullivan, Gary A; Jackson-Davis, Armitra L; Schrader, Kohl D; Xi, Yuan; Kulchaiyawat, Charlwit; Sebranek, Joseph G; Dickson, James S

    2012-12-01

    Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.

  15. Small doses, big troubles: modeling growth dynamics of organisms affecting microalgal production cultures in closed photobioreactors.

    PubMed

    Forehead, Hugh I; O'Kelly, Charles J

    2013-02-01

    The destruction of mass cultures of microalgae by biological contamination of culture medium is a pervasive and expensive problem, in industry and research. A mathematical model has been formulated that attempts to explain contaminant growth dynamics in closed photobioreactors (PBRs). The model simulates an initial growth phase without PBR dilution, followed by a production phase in which culture is intermittently removed. Contaminants can be introduced at any of these stages. The model shows how exponential growth from low initial inocula can lead to "explosive" growth in the population of contaminants, appearing days to weeks after inoculation. Principal influences are contaminant growth rate, PBR dilution rate, and the size of initial contaminant inoculum. Predictions corresponded closely with observed behavior of two contaminants, Uronema sp. and Neoparamoeba sp., found in operating PBRs. A simple, cheap and effective protocol was developed for short-term prediction of contamination in PBRs, using microscopy and archived samples.

  16. Role of the Placental Vitamin D Receptor in Modulating Feto-Placental Growth in Fetal Growth Restriction and Preeclampsia-Affected Pregnancies

    PubMed Central

    Murthi, Padma; Yong, Hannah E. J.; Ngyuen, Thy P. H.; Ellery, Stacey; Singh, Harmeet; Rahman, Rahana; Dickinson, Hayley; Walker, David W.; Davies-Tuck, Miranda; Wallace, Euan M.; Ebeling, Peter R.

    2016-01-01

    Fetal growth restriction (FGR) is a common pregnancy complication that affects up to 5% of pregnancies worldwide. Recent studies demonstrate that Vitamin D deficiency is implicated in reduced fetal growth, which may be rescued by supplementation of Vitamin D. Despite this, the pathway(s) by which Vitamin D modulate fetal growth remains to be investigated. Our own studies demonstrate that the Vitamin D receptor (VDR) is significantly decreased in placentae from human pregnancies complicated by FGR and contributes to abnormal placental trophoblast apoptosis and differentiation and regulation of cell-cycle genes in vitro. Thus, Vitamin D signaling is important for normal placental function and fetal growth. This review discusses the association of Vitamin D with fetal growth, the function of Vitamin D and its receptor in pregnancy, as well as the functional significance of a placental source of Vitamin D in FGR. Additionally, we propose that for Vitamin D to be clinically effective to prevent and manage FGR, the molecular mechanisms of Vitamin D and its receptor in modulating fetal growth requires further investigation. PMID:26924988

  17. Fibroblast cell interactions with human melanoma cells affect tumor cell growth as a function of tumor progression.

    PubMed Central

    Cornil, I; Theodorescu, D; Man, S; Herlyn, M; Jambrosic, J; Kerbel, R S

    1991-01-01

    It is known from a variety of experimental systems that the ability of tumor cells to grow locally and metastasize can be affected by the presence of adjacent normal tissues and cells, particularly mesenchymally derived stromal cells such as fibroblasts. However, the comparative influence of such normal cell-tumor cell interactions on tumor behavior has not been thoroughly investigated from the perspective of different stages of tumor progression. To address this question we assessed the influence of normal dermal fibroblasts on the growth of human melanoma cells obtained from different stages of tumor progression. We found that the in vitro growth of most (4 out of 5) melanoma cell lines derived from early-stage radial growth phase or vertical growth phase metastatically incompetent primary lesions is repressed by coculture with normal dermal fibroblasts, suggesting that negative homeostatic growth controls are still operative on melanoma cells from early stages of disease. On the other hand, 9 out of 11 melanoma cell lines derived from advanced metastatically competent vertical growth phase primary lesions, or from distant metastases, were found to be consistently stimulated to grow in the presence of dermal fibroblasts. Evidence was obtained to show that this discriminatory fibroblastic influence is mediated by soluble inhibitory and stimulatory growth factor(s). Taken together, these results indicate that fibroblast-derived signals can have antithetical growth effects on metastatic versus metastatically incompetent tumor subpopulations. This resultant conversion in responsiveness to host tissue environmental factors may confer upon small numbers of metastatically competent cells a growth advantage, allowing them to escape local growth constraints both in the primary tumor site and at distant ectopic tissue sites. PMID:2068080

  18. Larval development of Culex quinquefasciatus in water with low to moderate.

    PubMed

    Noori, Navideh; Lockaby, B Graeme; Kalin, Latif

    2015-12-01

    Population growth and urbanization have increased the potential habitats, and consequently the abundance of Culex quinquefasciatus, the southern house mosquito, a vector of West Nile Virus in urban areas. Water quality is critical in larval habitat distribution and in providing microbial food resources for larvae. A mesocosm experiment was designed to demonstrate which specific components of water chemistry are conducive to larval Culex mosquitoes. Dose-response relationships between larval development and NO3 , NH4 , and PO4 concentrations in stream water were developed through this experiment to describe the isolated effects of each nutrient on pre-adult development. The emergence pattern of Culex mosquitoes was found to be strongly related to certain nutrients, and results showed that breeding sites with higher PO4 or NO3 concentrations had higher larval survival rates. High NO3 concentrations favor the development of male mosquitoes and suppress the development of female mosquitoes, but those adult females that do emerge develop faster in containers with high NO3 levels compared to the reference group. The addition of PO4 in the absence of nitrogen sources to the larval habitat slowed larval development, however, it took fewer days for larvae to reach the pupal stage in containers with combinations of NO3 and PO4 or NH4 and PO4 nutrients. Results from this study may bolster efforts to control WNV in urban landscapes by exploring water quality conditions of Culex larval habitats that produce adult mosquitoes.

  19. Culture media profoundly affect Candida albicans and Candida tropicalis growth, adhesion and biofilm development

    PubMed Central

    Weerasekera, Manjula M; Wijesinghe, Gayan K; Jayarathna, Thilini A; Gunasekara, Chinthika P; Fernando, Neluka; Kottegoda, Nilwala; Samaranayake, Lakshman P

    2016-01-01

    As there are sparse data on the impact of growth media on the phenomenon of biofilm development for Candida we evaluated the efficacy of three culture media on growth, adhesion and biofilm formation of two pathogenic yeasts, Candida albicans and Candida tropicalis. The planktonic phase yeast growth, either as monocultures or mixed cultures, in sabouraud dextrose broth (SDB), yeast nitrogen base (YNB), and RPMI 1640 was compared, and adhesion as well as biofilm formation were monitored using MTT and crystal violet (CV) assays and scanning electron microscopy. Planktonic cells of C. albicans, C. tropicalis and their 1:1 co-culture showed maximal growth in SDB. C. albicans/C. tropicalis adhesion was significantly facilitated in RPMI 1640 although the YNB elicited the maximum growth for C. tropicalis. Similarly, the biofilm growth was uniformly higher for both species in RPMI 1640, and C. tropicalis was the slower biofilm former in all three media. Scanning electron microscopy images tended to confirm the results of MTT and CV assay. Taken together, our data indicate that researchers should pay heed to the choice of laboratory culture media when comparing relative planktonic/biofilm growth of Candida. There is also a need for standardisation of biofilm development media so as to facilitate cross comparisons between laboratories. PMID:27706381

  20. Nitrogen stress affects the turnover and size of nitrogen pools supplying leaf growth in a grass.

    PubMed

    Lehmeier, Christoph Andreas; Wild, Melanie; Schnyder, Hans

    2013-08-01

    The effect of nitrogen (N) stress on the pool system supplying currently assimilated and (re)mobilized N for leaf growth of a grass was explored by dynamic ¹⁵N labeling, assessment of total and labeled N import into leaf growth zones, and compartmental analysis of the label import data. Perennial ryegrass (Lolium perenne) plants, grown with low or high levels of N fertilization, were labeled with ¹⁵NO₃⁻/¹⁴NO₃⁻ from 2 h to more than 20 d. In both treatments, the tracer time course in N imported into the growth zones fitted a two-pool model (r² > 0.99). This consisted of a "substrate pool," which received N from current uptake and supplied the growth zone, and a recycling/mobilizing "store," which exchanged with the substrate pool. N deficiency halved the leaf elongation rate, decreased N import into the growth zone, lengthened the delay between tracer uptake and its arrival in the growth zone (2.2 h versus 0.9 h), slowed the turnover of the substrate pool (half-life of 3.2 h versus 0.6 h), and increased its size (12.4 μg versus 5.9 μg). The store contained the equivalent of approximately 10 times (low N) and approximately five times (high N) the total daily N import into the growth zone. Its turnover agreed with that of protein turnover. Remarkably, the relative contribution of mobilization to leaf growth was large and similar (approximately 45%) in both treatments. We conclude that turnover and size of the substrate pool are related to the sink strength of the growth zone, whereas the contribution of the store is influenced by partitioning between sinks.

  1. Do variations in leaf phenology affect radial growth variations in Fagus sylvatica?

    NASA Astrophysics Data System (ADS)

    Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka

    2015-08-01

    We used a dendrochronological and leaf phenology network of European beech ( Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial growth (annual xylem production and tree ring widths) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial growth. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree ring variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial growth may suggest that earlier leaf unfolding—as observed in a previous study—probably does not cause increased tree growth rates in beech in Slovenia.

  2. Density but not climate affects the population growth rate of guanacos ( Lama guanicoe) (Artiodactyla, Camelidae)

    PubMed Central

    Zubillaga, María; Skewes, Oscar; Soto, Nicolás; Rabinovich, Jorge E

    2014-01-01

    We analyzed the effects of population density and climatic variables on the rate of population growth in the guanaco ( Lama guanicoe), a wild camelid species in South America. We used a time series of 36 years (1977-2012) of population sampling in Tierra del Fuego, Chile. Individuals were grouped in three age-classes: newborns, juveniles, and adults; for each year a female population transition matrix was constructed, and the population growth rate (λ) was estimated for each year as the matrix highest positive eigenvalue. We applied a regression analysis with finite population growth rate (λ) as dependent variable, and total guanaco population, sheep population, annual mean precipitation, and winter mean temperature as independent variables, with and without time lags. The effect of guanaco population size was statistically significant, but the effects of the sheep population and the climatic variables on guanaco population growth rate were not statistically significant. PMID:25187878

  3. Do variations in leaf phenology affect radial growth variations in Fagus sylvatica?

    PubMed

    Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka

    2015-08-01

    We used a dendrochronological and leaf phenology network of European beech (Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial growth (annual xylem production and tree ring widths) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial growth. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree ring variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial growth may suggest that earlier leaf unfolding--as observed in a previous study--probably does not cause increased tree growth rates in beech in Slovenia.

  4. Traits, not origin, explain impacts of plants on larval amphibians.

    PubMed

    Cohen, Jillian S; Maerz, John C; Blossey, Bernd

    2012-01-01

    Managing habitats for the benefit of native fauna is a priority for many government and private agencies. Often, these agencies view nonnative plants as a threat to wildlife habitat, and they seek to control or eradicate nonnative plant populations. However, little is known about how nonnative plant invasions impact native fauna, and it is unclear whether managing these plants actually improves habitat quality for resident animals. Here, we compared the impacts of native and nonnative wetland plants on three species of native larval amphibians; we also examined whether plant traits explain the observed impacts. Specifically, we measured plant litter quality (carbon : nitrogen : phosphorus ratios, and percentages of lignin and soluble phenolics) and biomass, along with a suite of environmental conditions known to affect larval amphibians (hydroperiod, temperature, dissolved oxygen, and pH). Hydroperiod and plant traits, notably soluble phenolics, litter C:N ratio, and litter N:P ratio, impacted the likelihood that animals metamorphosed, the number of animals that metamorphosed, and the length of larval period. As hydroperiod decreased, the likelihood that amphibians achieved metamorphosis and the percentage of tadpoles that successfully metamorphosed also decreased. Increases in soluble phenolics, litter N:P ratio, and litter C:N ratio decreased the likelihood that tadpoles achieved metamorphosis, decreased the percentage of tadpoles metamorphosing, decreased metamorph production (total metamorph biomass), and increased the length of larval period. Interestingly, we found no difference in metamorphosis rates and length of larval period between habitats dominated by native and nonnative plants. Our findings have important implications for habitat management. We suggest that to improve habitats for native fauna, managers should focus on assembling a plant community with desirable traits rather than focusing only on plant origin.

  5. Effects of food limitation and pharmaceutical compounds on the larval development and morphology of Palaemon serratus.

    PubMed

    González-Ortegón, Enrique; Giménez, Luis; Blasco, Julian; Le Vay, Lewis

    2015-01-15

    Few ecotoxicological studies consider the roles of maternal influences and suboptimal environmental conditions when assessing the impact of pollutants on organisms. We studied the combined effects of pharmaceutical compounds, food condition and maternal body size on growth, development, body mass and morphology of larvae of the marine shrimp Palaemon serratus. Limited food availability is considered a factor leading to reduced survival and growth in marine crustacean larvae. It is known that P. serratus responses to food limitation vary among larvae hatched from females of different body length. The pharmaceuticals tested were the anti-inflammatory and analgesic diclofenac sodium (DS: at 77 μg L-1 and 720 μg L-1) the lipid regulator clofibric acid (CA: at 42 μg L-1 and 394 μg L-1) and the fungicide clotrimazole (CLZ: at 0.07 μg L-1 and 3.16 μg L-1). We observed morphological abnormalities in larvae exposed to CLZ. In addition, effects of this compound were stronger under food limitation leading to (1) reduced survival by 30%, (2) reduced juvenile body mass (22%) and (3) reduction in the number of molt stages (from 13 to 9) during larval development. This latter effect may indicate that CLZ reduced the larval capacity to respond to food limitation because development through a longer route, with additional stages, is considered an adaptive response to prioritize maintenance over morphogenesis. CA and DS affected developmental rate under food limitation but not growth or body mass. The toxic effects of CLZ, at lower concentrations than CA and DS, were stronger in larvae with higher body mass, hatched from the largest females. This suggests that maternal influences and suboptimal environmental conditions should be further studied to inform modeling of the effects of emergent compounds on larvae of marine coastal species.

  6. Growth and production of a stream stonefly: influences of diet and temperature. [Soyedina carolinesis

    SciTech Connect

    Sweeney, B.W.; Vannote, R.L.

    1986-10-01

    The natural influx of leaf litter from a hardwood forest to sections of two spring seeps and a spring brook was excluded for two years and replaced with equivalent amounts of leaves from specific tree species. Larval growth, mortality, and productivity, as well as the timing of emergence and the size of adults, were assessed in the naturally occurring populations of Soyedina carolinesis, and the differences related to differences in available food and in temperature among study sites. During the first experimental year, larvae fed only on sugar maple or chestnut oak leaves exhibited the same rate and magnitude of growth as larvae fed the natural mix of leaves collected from the surrounding forest. Larval growth rates and adult size seemed lower on monospecific diets of hickory, American beech, and red oak leaves relative to the natural, mixed leaf diets. Adult emergence occurred on or about the same date for most diets. Larval production ranged from 1382 to 5500 mg x m/sup -2/ x yr/sup -1/; there was no correlation between larval growth rate and productivity on a given diet. During the second experimental year, most sites that had been supplied with single-species leaf diets during the first experimental year were provided with sugar maple leaves only. This was an attempt to evaluate site-to-site differences in habitat quality (other than diet) that might affect the growth performance of larvae. The amount of variation in larval growth rate and adult size among sites having a common diet was equal to or greater than among-site variation during the previous year, when each site differed in leaf diet. In the spring brook experiment, both diet and location within the brook exerted significant effects on larval growth rate and adult size.

  7. Affective Determinants of Anxiety and Depression Development in Children and Adolescents: An Individual Growth Curve Analysis

    ERIC Educational Resources Information Center

    De Bolle, Marleen; De Clercq, Barbara; Decuyper, Mieke; De Fruyt, Filip

    2011-01-01

    The tripartite model (in Clark and Watson, "J Abnorm Psychol" 100:316-336, 1991) comprises Negative Affect (NA), Positive Affect (PA), and Physiological Hyperarousal (PH), three temperamental-based dimensions. The current study examined the tripartite model's assumptions that (a) NA interacts with PA to predict subsequent depressive (but not…

  8. How Will Global Environmental Changes Affect the Growth of Alien Plants?

    PubMed Central

    Jia, Jujie; Dai, Zhicong; Li, Feng; Liu, Yanjie

    2016-01-01

    Global environmental changes can create novel habitats, promoting the growth of alien plants that often exhibit broad environmental tolerance and high phenotypic plasticity. However, the mechanisms underlying these growth promotory effects are unknown at present. Here, we conducted a phylogenetically controlled meta-analysis using data from 111 published studies encompassing the responses of 129 alien plants to global warming, increased precipitation, N deposition, and CO2 enrichment. We compared the differences in the responses of alien plants to the four global environmental change factors across six categories of functional traits between woody and non-woody life forms as well as C3 and C4 photosynthetic pathways. Our results showed that all four global change factors promote alien plant growth. Warming had a more positive effect on C4 than C3 plants. Although the effects of the four factors on the functional traits of alien plants were variable, plant growth was mainly promoted via an increase in growth rate and size. Our data suggest that potential future global environmental changes could further facilitate alien plant growth. PMID:27847511

  9. How Will Global Environmental Changes Affect the Growth of Alien Plants?

    PubMed

    Jia, Jujie; Dai, Zhicong; Li, Feng; Liu, Yanjie

    2016-01-01

    Global environmental changes can create novel habitats, promoting the growth of alien plants that often exhibit broad environmental tolerance and high phenotypic plasticity. However, the mechanisms underlying these growth promotory effects are unknown at present. Here, we conducted a phylogenetically controlled meta-analysis using data from 111 published studies encompassing the responses of 129 alien plants to global warming, increased precipitation, N deposition, and CO2 enrichment. We compared the differences in the responses of alien plants to the four global environmental change factors across six categories of functional traits between woody and non-woody life forms as well as C3 and C4 photosynthetic pathways. Our results showed that all four global change factors promote alien plant growth. Warming had a more positive effect on C4 than C3 plants. Although the effects of the four factors on the functional traits of alien plants were variable, plant growth was mainly promoted via an increase in growth rate and size. Our data suggest that potential future global environmental changes could further facilitate alien plant growth.

  10. Diffuse growth pattern affects E-cadherin expression in invasive breast cancer.

    PubMed

    Brinck, Ulrich; Jacobs, Susanne; Neuss, Michael; Tory, Kalman; Rath, Werner; Kulle, Bettina; Füzesi, Laszlo

    2004-01-01

    We investigated the correlations between growth patterns and E-cadherin expression by immunohistochemistry and the presence of mutations of exons 6-10 of the E-cadherin gene by PCR-SSCP, in 79 cases of invasive lobular and ductal breast cancer. E-cadherin expression showed a tendency to be lower in lobular than in ductal carcinomas (p=0.064). In 60% of lobular carcinomas the diffuse growth pattern and in 72% of ductal carcinomas the compact growth pattern predominated. E-cadherin expression was significantly lower in diffuse than in compact tumor area (p<0.001) and not related to carcinoma type when it was considered in tumor areas with either diffuse (p=0.278) or compact (p=0.128) growth pattern. No mutations were detected. In conclusion, loss of E-cadherin expression is related to an increase of diffuse growth pattern in both lobular and ductal types of breast cancer, and the differential proportions of growth patterns in both tumor types cause the tendency for lower E-cadherin expression in the lobular type.

  11. Bone quality is affected by food restriction and by nutrition-induced catch-up growth.

    PubMed

    Pando, Rakefet; Masarwi, Majdi; Shtaif, Biana; Idelevich, Anna; Monsonego-Ornan, Efrat; Shahar, Ron; Phillip, Moshe; Gat-Yablonski, Galia

    2014-12-01

    Growth stunting constitutes the most common effect of malnutrition. When the primary cause of malnutrition is resolved, catch-up (CU) growth usually occurs. In this study, we have explored the effect of food restriction (RES) and refeeding on bone structure and mechanical properties. Sprague-Dawley male rats aged 24 days were subjected to 10 days of 40% RES, followed by refeeding for 1 (CU) or 26 days long-term CU (LTCU). The rats fed ad libitum served as controls. The growth plates were measured, osteoclasts were identified using tartrate-resistant acid phosphatase staining, and micro-computed tomography (CT) scanning and mechanical testing were used to study structure and mechanical properties. Micro-CT analysis showed that RES led to a significant reduction in trabecular BV/TV and trabecular number (Tb.N), concomitant with an increase in trabecular separation (Tb.Sp). Trabecular BV/TV and Tb.N were significantly greater in the CU group than in the RES in both short- and long-term experiments. Mechanical testing showed that RES led to weaker and less compliant bones; interestingly, bones of the CU group were also more fragile after 1 day of CU. Longer term of refeeding enabled correction of the bone parameters; however, LTCU did not achieve full recovery. These results suggest that RES in young rats attenuated growth and reduced trabecular bone parameters. While nutrition-induced CU growth led to an immediate increase in epiphyseal growth plate height and active bone modeling, it was also associated with a transient reduction in bone quality. This should be taken into consideration when treating children undergoing CU growth.

  12. Condition of larval red snapper (Lutjanus campechanus) relative to environmental variability and the Deepwater Horizon oil spill

    NASA Astrophysics Data System (ADS)

    Hernandez, F. J., Jr.; Filbrun, J. E.; Fang, J.; Ransom, J. T.

    2016-09-01

    The Deepwater Horizon oil spill (DWHOS) spatially and temporally overlapped with the spawning of many fish species, including Red Snapper, one of the most economically important reef fish in the Gulf of Mexico. To investigate potential impacts of the DWHOS on larval Red Snapper, data from a long-term ichthyoplankton survey off the coast of Alabama were used to examine: (1) larval abundances among pre-impact (2007-2009), impact (2010), and post-impact (2011, 2013) periods; (2) proxies for larval condition (size-adjusted morphometric relationships and dry weight) among the same periods; and (3) the effects of background environmental variation on larval condition. We found that larval Red Snapper were in poorer body condition during 2010, 2011, and 2013 as compared to the 2007-2009 period, a trend that was strongly (and negatively) related to variation in Mobile Bay freshwater discharge. However, larvae collected during and after 2010 were in relatively poor condition even after accounting for variation in freshwater discharge and other environmental variables. By contrast, no differences in larval abundance were detected during these survey years. Taken together, larval supply did not change relative to the timing of the DWHOS, but larval condition was negatively impacted. Even small changes in condition can affect larval survival, so these trends may have consequences for recruitment of larvae to juvenile and adult life stages.

  13. Role of circulation scales and water mass distributions on larval fish habitats in the Eastern Tropical Pacific off Mexico

    NASA Astrophysics Data System (ADS)

    León-Chávez, Cristina A.; Beier, Emilio; Sánchez-Velasco, Laura; Barton, Eric Desmond; Godínez, Victor M.

    2015-06-01

    On the basis of five oceanographic cruises carried out in the Eastern Tropical Pacific off Mexico, relationships between the larval fish habitats (areas inhabited by larval fish assemblages) and the environmental circulation scales (mesoscale, seasonal, and interannual) were examined. Analysis of in situ data over a grid of hydrographic stations and oblique zooplankton hauls with bongo net (505 µm) was combined with orthogonal robust functions decomposition applied to altimetry anomalies obtained from satellite. During both cool (March and June) and warm (August and November) periods, Bray-Curtis dissimilarity Index defined three recurrent larval fish habitats which varied in species composition and extent as a function of the environmental scales. The variability of the Tropical larval fish habitat (characterized by high species richness, and dominated by Vinciguerria lucetia, Diogenichthys laternatus, and Diaphus pacificus) was associated with the seasonal changes. The Transitional-California Current larval fish habitat (dominated by V. lucetia and D. laternatus, with lower mean abundance and lower species richness than in the Tropical habitat) and Coastal-and-Upwelling larval fish habitat (dominated by Bregmaceros bathymaster) was associated mainly with mesoscale activity induced by eddies and with coastal upwelling. During February 2010, the Tropical larval fish habitat predominated offshore and the Transitional-California Current larval fish habitat was not present, which we attribute to the effect of El Niño conditions. Thus, the mesoscale, seasonal, and interannual environmental scales affect the composition and extension of larval fish habitats.

  14. A critical functional missense mutation (H173R) in the bovine PROP1 gene significantly affects growth traits in cattle.

    PubMed

    Pan, Chuanying; Wu, Chongyang; Jia, Wenchao; Xu, Yao; Lei, Chuzhao; Hu, Shenrong; Lan, Xianyong; Chen, Hong

    2013-12-01

    The PROP1 protein, encoded by the prophet of Pit-1 (PROP1) gene, exhibits both DNA-binding and transcriptional activation abilities. Its expression leads to the ontogenesis of growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), and pituitary hormone. The missense mutation H173R in PROP1 may result in deficiencies of GH, PRL, TSH, and Pit-1, thereby affecting growth traits. The objective of this study was to characterize the H173R mutation within the PROP1 gene and examine its associations with growth traits in cattle. Accordingly, the H173R mutation was genotyped in 1207 cows belonging to five Chinese native breeds. Three genotypes were identified among the specimens, with genotype AA being the major one. Consequently, the "G" allele was the minor allele. Association testing revealed that the H173R mutation was significantly associated with body weight, average daily weight gain and physical parameters in the analyzed breeds. Interestingly, the cows with genotype AG and/or AA had superior growth traits compared with those expressing the GG genotype, in all tested breeds. These findings revealed that the "A" allele had positive effects on growth traits, which was consistent with the increasing binding ability and enhanced activation capacity associated with the bovine isoform PROP1-173H, representing the "A" allele. Therefore, the H173R mutation can be considered as a DNA marker for selecting individuals with superior growth traits, thereby contributing to research on breeding and genetics in the beef industry.

  15. Autocrine Transforming Growth Factor-β Growth Pathway in Murine Osteosarcoma Cell Lines Associated with Inability to Affect Phosphorylation of Retinoblastoma Protein

    PubMed Central

    Letterio, John J.; Yeung, Choh L.; Pegtel, Michiel; Helman, Lee J.

    2000-01-01

    Purpose. Production of active transforming growth factor-β (TGF-β ) by human osteosarcoma may contribute to malignant progression through mechanisms that include induction of angiogenesis, immune suppression and autocrine growth stimulation of tumor cell growth.To study events associated with induction of cell proliferation by TGF-β , we have evaluated the TGF-β pathway in two murine osteosarcoma cell lines, K7 and K12. Results. Northern and immunohistochemical analyses show that each cell line expressesTGF-β1 and TGF-β3 mRNA and protein. Both cell lines secrete activeTGF-β 1 and display a 30–50% reduction in growth when cultured in the presence of a TGF-β blocking antibody. Expression of TGF-β receptors TβRI, TβRII and TβRIII is demonstrated by affinity labeling with 125 -TGF-β 1, and the intermediates, Smads 2, 3 and 4, are uniformly expressed. Smads 2 and 3 are phosphorylated in response toTGF-β , while pRb phosphorylation in each osteosarcoma cell line is not affected by either exogenousTGF-β or TGF-β antibody. Conclusions. The data implicate events downstream of Smad activation, including impaired regulation of pRb, in the lack of a growth inhibitory response toTGF-β , and indicate that this murine model of osteosarcoma is valid for investigating the roles of autocrineTGF-β in vivo. PMID:18521287

  16. Optimizing larval assessment to support sea lamprey control in the Great Lakes

    USGS Publications Warehouse

    Hansen, Michael J.; Adams, Jean V.; Cuddy, Douglas W.; Richards, Jessica M.; Fodale, Michael F.; Larson, Geraldine L.; Ollila, Dale J.; Slade, Jeffrey W.; Steeves, Todd B.; Young, Robert J.; Zerrenner, Adam

    2003-01-01

    Elements of the larval sea lamprey (Petromyzon marinus) assessment program that most strongly influence the chemical treatment program were analyzed, including selection of streams for larval surveys, allocation of sampling effort among stream reaches, allocation of sampling effort among habitat types, estimation of daily growth rates, and estimation of metamorphosis rates, to determine how uncertainty in each element influenced the stream selection program. First, the stream selection model based on current larval assessment sampling protocol significantly underestimated transforming sea lam-prey abundance, transforming sea lampreys killed, and marginal costs per sea lamprey killed, compared to a protocol that included more years of data (especially for large streams). Second, larval density in streams varied significantly with Type-I habitat area, but not with total area or reach length. Third, the ratio of larval density between Type-I and Type-II habitat varied significantly among streams, and that the optimal allocation of sampling effort varied with the proportion of habitat types and variability of larval density within each habitat. Fourth, mean length varied significantly among streams and years. Last, size at metamorphosis varied more among years than within or among regions and that metamorphosis varied significantly among streams within regions. Study results indicate that: (1) the stream selection model should be used to identify streams with potentially high residual populations of larval sea lampreys; (2) larval sampling in Type-II habitat should be initiated in all streams by increasing sampling in Type-II habitat to 50% of the sampling effort in Type-I habitat; and (3) methods should be investigated to reduce uncertainty in estimates of sea lamprey production, with emphasis on those that reduce the uncertainty associated with larval length at the end of the growing season and those used to predict metamorphosis.

  17. Growth performance and feed conversion efficiency of three edible mealworm species (Coleoptera: Tenebrionidae) on diets composed of organic by-products.

    PubMed

    van Broekhoven, Sarah; Oonincx, Dennis G A B; van Huis, Arnold; van Loon, Joop J A

    2015-02-01

    Insects receive increasing attention as an alternative protein-rich food source for humans. Producing edible insects on diets composed of organic by-products could increase sustainability. In addition, insect growth rate and body composition, and hence nutritional quality, can be altered by diet. Three edible mealworm species Tenebrio molitor L., Zophobas atratus Fab. and Alphitobius diaperinus Panzer were grown on diets composed of organic by-products originating from beer brewing, bread/cookie baking, potato processing and bioethanol production. Experimental diets differed with respect to protein and starch content. Larval growth and survival was monitored. Moreover, effects of dietary composition on feed conversion efficiency and mealworm crude protein and fatty acid profile were assessed. Diet affected mealworm development and feed conversion efficiency such that diets high in yeast-derived protein appear favourable, compared to diets used by commercial breeders, with respect to shortening larval development time, reducing mortality and increasing weight gain. Diet also affected the chemical composition of mealworms. Larval protein content was stable on diets that differed 2-3-fold in protein content, whereas dietary fat did have an effect on larval fat content and fatty acid profile. However, larval fatty acid profile did not necessarily follow the same trend as dietary fatty acid composition. Diets that allowed for fast larval growth and low mortality in this study led to a comparable or less favourable n6/n3 fatty acid ratio compared to control diets used by commercial breeders. In conclusion, the mealworm species used in this study can be grown successfully on diets composed of organic by-products. Diet composition did not influence larval protein content, but did alter larval fat composition to a certain extent.

  18. Warfarin inhibits metastasis of Mtln3 rat mammary carcinoma without affecting primary tumour growth.

    PubMed Central

    McCulloch, P.; George, W. D.

    1989-01-01

    Coumarin anticoagulants inhibit metastasis in several animal models, but the mechanism of this effect is uncertain. In order to determine the role of cytotoxic and/or cytostatic actions of coumarins on the tumour cells, we have studied the effects of warfarin on tumour cell growth in a model in which tumour metastasis is inhibited by this drug. Clonogenic assay, growth curve analysis and thymidine labelling index revealed that warfarin had no effects on Mtln3 mammary carcinoma cell growth in vitro at concentrations below 1 mM. The growth rate of subcutaneously implanted Mtln3 tumour deposits in female F344 rats, assessed by weight and by stathmokinetic analysis of the tumour tissue, was identical in warfarin-treated and control animals. Spontaneous metastasis from such tumours to the lungs was, however, significantly reduced in warfarin-treated animals (median 0 pulmonary tumours per animal in warfarin treated, eight tumours per animal in control animals; P less than 0.05, Mann-Whitney). The mean plasma warfarin concentration in warfarin treated rats was 1.63 microM. These results suggest that warfarin treatment of the host animal can inhibit tumour metastasis without having any direct or indirect effect on the growth rate of the tumour cells. PMID:2930682

  19. Slow growth of the overexploited milk shark Rhizoprionodon acutus affects its sustainability in West Africa.

    PubMed

    Ba, A; Diouf, K; Guilhaumon, F; Panfili, J

    2015-10-01

    Age and growth of Rhizoprionodon acutus were estimated from vertebrae age bands. From December 2009 to November 2010, 423 R. acutus between 37 and 112 cm total length (LT ) were sampled along the Senegalese coast. Marginal increment ratio was used to check annual band deposition. Three growth models were adjusted to the length at age and compared using Akaike's information criterion. The Gompertz growth model with estimated size at birth appeared to be the best and resulted in growth parameters of L∞ = 139.55 (LT ) and K = 0.17 year(-1) for females and L∞ = 126.52 (LT ) and K = 0.18 year(-1) for males. The largest female and male examined were 8 and 9 years old, but the majority was between 1 and 3 years old. Ages at maturity estimated were 5.8 and 4.8 years for females and males, respectively. These results suggest that R. acutus is a slow-growing species, which render the species particularly vulnerable to heavy fishery exploitation. The growth parameters estimated in this study are crucial for stock assessments and for demographic analyses to evaluate the sustainability of commercial harvests.

  20. [Canine peritoneal larval cestodosis caused by Mesocestoides spp. larval stages].

    PubMed

    Häußler, T C; Peppler, C; Schmitz, S; Bauer, C; Hirzmann, J; Kramer, M

    2016-01-01

    In a female dog with unspecific clinical symptoms, sonography detected a hyperechoic mass in the middle abdomen and blood analysis a middle grade systemic inflammatory reaction. Laparotomy revealed a peritoneal larval cestodosis (PLC). The diagnosis of an infection with tetrathyridia of Mesocestoides spp. was confirmed by parasitological examination and molecularbiological analysis. Reduction of the intra-abdominal parasitic load as well as a high dose administration of fenbendazole over 3 months led to a successful treatment which could be documented sonographically and by decreased concentrations of C-reactive protein (CRP). Seven months after discontinuation of fenbendazole administration, PLC recurred, pre-empted by an elevation of serum CRP values. According to the literature a life-long fenbendazole treatment was initiated. In cases of unclear chronic granulomatous inflammations in the abdominal cavity in dogs, PLC should be considered. CRP concentration and sonographic examinations are suitable to control for treatment success and a possibly occurring relapse.

  1. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    SciTech Connect

    Smith, James N.; McMurry, Peter H.

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  2. How maternal malnutrition affects linear growth and development in the offspring.

    PubMed

    Papathakis, Peggy C; Singh, Lauren N; Manary, Mark J

    2016-11-05

    Maternal malnutrition is common in the developing world and has detrimental effects on both the mother and infant. Pre-pregnancy nutritional status and weight gain during pregnancy are positively related to fetal growth and development. Internationally, there is no agreement on the method of diagnosis or treatment of moderate or severe malnutrition during pregnancy. Establishing clear guidelines for diagnosis and treatment will be essential in elevating the problem. Possible anthropometric measurements used to detect and monitor maternal malnutrition include pre-pregnancy BMI, weight gain, and mid upper arm circumference. Food supplements have the potential to increase gestational weight gain and energy intake which are positively associated with fetal growth and development. Overall more studies are needed to conclude the impact of food/nutrient supplements on infant growth in undernourished pregnant women in developing countries. Currently, a study underway may provide much needed documentation of the benefits of treating malnutrition in pregnancy.

  3. Low intensity electromagnetic irradiation with 70.6 and 73 GHz frequencies affects Escherichia coli growth and changes water properties.

    PubMed

    Torgomyan, Heghine; Kalantaryan, Vitaly; Trchounian, Armen

    2011-07-01

    The low intensity electromagnetic irradiation (EMI) of the 70.6 and 73 GHz frequency is resonant for Escherichia coli but not for water. In this study, E. coli irradiation with this EMI during 1 h directly and in bi-distilled water or in the assay buffer with those frequencies resulted with noticeable changes in bacterial growth parameters. Furthermore, after EMI, 2 h rest of bacteria renewed their growth in 1.2-fold, but repeated EMI--had no significant action. Moreover, water absorbance, pH, and electric conductance were changed markedly after such irradiation. The results point out that EMI of the 70.6 and 73 GHz frequency can interact with bacteria affecting growth and in the same time with the surrounding medium (water) as well.

  4. Collaborative Project: Understanding the Chemical Processes tat Affect Growth rates of Freshly Nucleated Particles

    SciTech Connect

    McMurry, Peter; Smuth, James

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate.

  5. Elevated pressure of carbon dioxide affects growth of thermophilic Petrotoga sp.

    NASA Astrophysics Data System (ADS)

    Rakoczy, Jana; Gniese, Claudia; Schippers, Axel; Schlömann, Michael; Krüger, Martin

    2014-05-01

    Carbon capture and storage (CCS) is considered a promising new technology which reduces carbon dioxide emissions into the atmosphere and thereby decelerates global warming. During CCS, carbon dioxide is captured from emission sources (e.g. fossil fuel power plants or other industries), pressurised, and finally stored in deep geological formations, such as former gas or oil reservoirs as well as saline aquifers. However, with CCS being a very young technology, there are a number of unknown factors that need to be investigated before declaring CCS as being safe. Our research investigates the effect of high carbon dioxide concentrations and pressures on an indigenous microorganism that colonises a potential storage site. Growth experiments were conducted using the thermophilic thiosulphate-reducing bacterium Petrotoga sp., isolated from formation water of the gas reservoir Schneeren (Lower Saxony, Germany), situated in the Northern German Plain. Growth (OD600) was monitored over one growth cycle (10 days) at different carbon dioxide concentrations (50%, 100%, and 150% in the gas phase), and was compared to control cultures grown with 20% carbon dioxide. An additional growth experiment was performed over a period of 145 days with repeated subcultivation steps in order to detect long-term effects of carbon dioxide. Cultivation over 10 days at 50% and 100% carbon dioxide slightly reduced cell growth. In contrast, long-term cultivation at 150% carbon dioxide reduced cell growth and finally led to cell death. This suggested a more pronounced effect of carbon dioxide at prolonged cultivation and stresses the need for a closer consideration of long-term effects. Experiments with supercritical carbon dioxide at 100 bar completely inhibited growth of freshly inoculated cultures and also caused a rapid decrease of growth of a pre-grown culture. This demonstrated that supercritical carbon dioxide had a sterilising effect on cells. This effect was not observed in control cultures

  6. Cytohistological analysis of roots whose growth is affected by a 60-Hz electric field

    SciTech Connect

    Brulfert, A.; Miller, M.W.; Robertson, D.; Dooley, D.A.; Economou, P.

    1985-01-01

    Roots of Pisum sativum were exposed for 48 h to 60-Hz electric fields of 430 V/m in an aqueous inorganic growth medium. The growth in length of the exposed roots was 44% of that for control roots. Root tips were analyzed for mitotic index and cell cycle duration. Mature, differentiated root sections from tissue produced after electrode energization were analyzed for cell lengths and number of files. The major reason for the observation that exposed roots are shorter than control roots is that cell elongation in the former is greatly diminished relative to controls. 15 references, 1 figures, 4 tables.

  7. Does temperature and oxygen affect duration of intramarsupial development and juvenile growth in the terrestrial isopod Porcellio scaber (Crustacea, Malacostraca)?

    PubMed Central

    Horváthová, Terézia; Antol, Andrzej; Czarnoleski, Marcin; Kramarz, Paulina; Bauchinger, Ulf; Labecka, Anna Maria; Kozłowski, Jan

    2015-01-01

    Abstract According to the temperature-size rule (TSR), ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O2) and temperature (15 °C and 22 °C) on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium), and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellio scaber). Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment. PMID:26261441

  8. Does temperature and oxygen affect duration of intramarsupial development and juvenile growth in the terrestrial isopod Porcellioscaber (Crustacea, Malacostraca)?

    PubMed

    Horváthová, Terézia; Antol, Andrzej; Czarnoleski, Marcin; Kramarz, Paulina; Bauchinger, Ulf; Labecka, Anna Maria; Kozłowski, Jan

    2015-01-01

    According to the temperature-size rule (TSR), ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O2) and temperature (15 °C and 22 °C) on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium), and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellioscaber). Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment.

  9. Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis).

    PubMed

    Owerkowicz, Tomasz; Elsey, Ruth M; Hicks, James W

    2009-05-01

    Recent palaeoatmospheric models suggest large-scale fluctuations in ambient oxygen level over the past 550 million years. To better understand how global hypoxia and hyperoxia might have affected the growth and physiology of contemporary vertebrates, we incubated eggs and raised hatchlings of the American alligator. Crocodilians are one of few vertebrate taxa that survived these global changes with distinctly conservative morphology. We maintained animals at 30 degrees C under chronic hypoxia (12% O(2)), normoxia (21% O(2)) or hyperoxia (30% O(2)). At hatching, hypoxic animals were significantly smaller than their normoxic and hyperoxic siblings. Over the course of 3 months, post-hatching growth was fastest under hyperoxia and slowest under hypoxia. Hypoxia, but not hyperoxia, caused distinct scaling of major visceral organs-reduction of liver mass, enlargement of the heart and accelerated growth of lungs. When absorptive and post-absorptive metabolic rates were measured in juvenile alligators, the increase in oxygen consumption rate due to digestion/absorption of food was greatest in hyperoxic alligators and smallest in hypoxic ones. Hyperoxic alligators exhibited the lowest breathing rate and highest oxygen consumption per breath. We suggest that, despite compensatory cardiopulmonary remodelling, growth of hypoxic alligators is constrained by low atmospheric oxygen supply, which may limit their food utilisation capacity. Conversely, the combination of elevated metabolism and low cost of breathing in hyperoxic alligators allows for a greater proportion of metabolised energy to be available for growth. This suggests that growth and metabolic patterns of extinct vertebrates would have been significantly affected by changes in the atmospheric oxygen level.

  10. Mechanistic insights into the effects of climate change on larval cod.

    PubMed

    Kristiansen, Trond; Stock, Charles; Drinkwater, Kenneth F; Curchitser, Enrique N

    2014-05-01

    Understanding the biophysical mechanisms that shape variability in fisheries recruitment is critical for estimating the effects of climate change on fisheries. In this study, we used an Earth System Model (ESM) and a mechanistic individual-based model (IBM) for larval fish to analyze how climate change may impact the growth and survival of larval cod in the North Atlantic. We focused our analysis on five regions that span the current geographical range of cod and are known to contain important spawning populations. Under the SRES A2 (high emissions) scenario, the ESM-projected surface ocean temperatures are expected to increase by >1 °C for 3 of the 5 regions, and stratification is expected to increase at all sites between 1950-1999 and 2050-2099. This enhanced stratification is projected to decrease large (>5 μm ESD) phytoplankton productivity and mesozooplankton biomass at all 5 sites. Higher temperatures are projected to increase larval metabolic costs, which combined with decreased food resources will reduce larval weight, increase the probability of larvae dying from starvation and increase larval exposure to visual and invertebrate predators at most sites. If current concentrations of piscivore and invertebrate predators are maintained, larval survival is projected to decrease at all five sites by 2050-2099. In contrast to past observed responses to climate variability in which warm anomalies led to better recruitment in cold-water stocks, our simulations indicated that reduced prey availability under climate change may cause a reduction in larval survival despite higher temperatures in these regions. In the lower prey environment projected under climate change, higher metabolic costs due to higher temperatures outweigh the advantages of higher growth potential, leading to negative effects on northern cod stocks. Our results provide an important first large-scale assessment of the impacts of climate change on larval cod in the North Atlantic.

  11. Does the introduced brook trout ( Salvelinus fontinalis) affect growth of the native brown trout ( Salmo trutta)?

    NASA Astrophysics Data System (ADS)

    Korsu, Kai; Huusko, Ari; Muotka, Timo

    2009-03-01

    Non-native brook trout have become widely established in North European streams. We combined evidence from an artificial-stream experiment and drainage-scale field surveys to examine whether brook trout suppressed the growth of the native brown trout (age 0 to age 2). Our experimental results demonstrated that brown trout were unaffected by the presence of brook trout but that brook trout showed reduced growth in the presence of brown trout. However, the growth reduction only appeared in the experimental setting, indicating that the reduced spatial constraint of the experimental system may have forced the fish to unnaturally intense interactions. Indeed, in the field, no effect of either species on the growth of the putative competitor was detected. These results caution against uncritical acceptance of findings from small-scale experiments because they rarely scale up to more complex field situations. This and earlier work suggest that the establishment of brook trout in North European streams has taken place mainly because of the availability of unoccupied (or underutilized) niche space, rather than as a result of species trait combinations or interspecific competition per se.

  12. The Ecology of Technological Progress: How Symbiosis and Competition Affect the Growth of Technology Domains

    ERIC Educational Resources Information Center

    Carnabuci, Gianluca

    2010-01-01

    We show that the progress of technological knowledge is an inherently ecological process, wherein the growth rate of each technology domain depends on dynamics occurring in "other" technology domains. We identify two sources of ecological interdependence among technology domains. First, there are symbiotic interdependencies, implying…

  13. The Ketogenic Diet Does Not Affect Growth of Hedgehog Pathway Medulloblastoma in Mice.

    PubMed

    Dang, Mai T; Wehrli, Suzanne; Dang, Chi V; Curran, Tom

    2015-01-01

    The altered metabolism of cancer cells has long been viewed as a potential target for therapeutic intervention. In particular, brain tumors often display heightened glycolysis, even in the presence of oxygen. A subset of medulloblastoma, the most prevalent malignant brain tumor in children, arises as a consequence of activating mutations in the Hedgehog (HH) pathway, which has been shown to promote aerobic glycolysis. Therefore, we hypothesized that a low carbohydrate, high fat ketogenic diet would suppress tumor growth in a genetically engineered mouse model of medulloblastoma. However, we found that the ketogenic diet did not slow the growth of spontaneous tumors or allograft flank tumors, and it did not exhibit synergy with a small molecule inhibitor of Smoothened. Serum insulin was significantly reduced in mice fed the ketogenic diet, but no alteration in PI3 kinase activity was observed. These findings indicate that while the ketogenic diet may be effective in inhibiting growth of other tumor types, it does not slow the growth of HH-medulloblastoma in mice.

  14. Rate of Physical Growth and Its Affect on Head Start Children's Motor and Cognitive Development.

    ERIC Educational Resources Information Center

    Marcon, Rebecca A.

    In the United States, growth retardation is higher among low-income children, with adverse cognitive effects of undernutrition more prevalent when combined with poverty. This study examined anthropometric indicators of physical development and their relationship to motor and cognitive development in Head Start children. Motor integration and…

  15. Factors Affecting the Growth and Usage of a Student Mental Health Service

    ERIC Educational Resources Information Center

    Amaranto, Ernesto A.; Wepman, Barry J.

    1978-01-01

    The five-year growth of an active Student Mental Health Service (SMHS) in an urban academic health center is described. The function of SMHS is limited strictly to therapeutic and consultative services for the students and operates as an outpatient treatment facility using a standard 12-session goal-oriented treatment plan. (LBH)

  16. Lysine supplementation of commercial fishmeal-free diet in hybrid striped bass affect growth expression genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Substitution of fishmeal with alternate proteins in aquafeeds often results in dietary imbalances of first-limiting essential amino acids (EAA) and poorer fish performance. Previously, we conducted a growth trial to test the hypothesis that ideal protein theory accurately predicts first-limiting ami...

  17. Intrauterine Cannabis Exposure Affects Fetal Growth Trajectories: The Generation R Study

    ERIC Educational Resources Information Center

    El Marroun, Hanan; Tiemeier, Henning; Steegers, Eric A. P.; Jaddoe, Vincent W. V.; Hofman, Albert; Verhulst, Frank C.; van den Brink, Wim; Huizink, Anja C.

    2009-01-01

    Objective: Cannabis is the most commonly consumed illicit drug among pregnant women. Intrauterine exposure to cannabis may result in risks for the developing fetus. The importance of intrauterine growth on subsequent psychological and behavioral child development has been demonstrated. This study examined the relation between maternal cannabis use…

  18. Runoff nutrient transport as affected by land application method, swine growth stage, and runoff rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to measure the effects of slurry application method, swine growth stage, and flow rate on runoff nutrient transport. Swine slurry was obtained from production units containing grower pigs, finisher pigs, or sows and gilts. The swine slurry was applied using broadcast, disk, ...

  19. Factors Affecting Growth of Tengmalm's Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order.

    PubMed

    Zárybnická, Markéta; Riegert, Jan; Brejšková, Lucie; Šindelář, Jiří; Kouba, Marek; Hanel, Jan; Popelková, Alena; Menclová, Petra; Tomášek, Václav; Šťastný, Karel

    2015-01-01

    In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm's owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl's main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species.

  20. Factors affecting growth and survival of the asiatic clam Corbicula sp. under controlled laboratory conditions

    SciTech Connect

    Double, D.D.; Daly, D.S.; Abernethy, C.S.

    1983-04-01

    Growth of Corbicula sp. was determined in relation to food supply, water temperature, and clam size as an aid to researchers conducting chronic effects toxicity studies. Water temperatures for the two 84-day test series were 10, 20, and 30/sup 0/C. Linear models provided good relationships (r/sup 2/ > 0.90) between clam shell length (SL), total weight (TW), and wet/dry tissue weights. Clam growth was minimal during low phytoplankton densities (approx. 300 cells/ml), and all three size groups lost weight at 20 and 30/sup 0/C. Mortality of small clams at 30/sup 0/C was 100% after 71 days. At phytoplankton densities > 1000 cells/ml, overall differences in growth with respect to clam size and temperature were detectable at p < 0.01; growth of all clam groups was greatest at 30/sup 0/C. Small clams exhibited the greatest absolute increase in mean shell length at all test temperatures, and weight gains were similar to those of medium and large clams.

  1. Does Year Round Schooling Affect the Outcome and Growth of California's API Scores?

    ERIC Educational Resources Information Center

    Wu, Amery D.; Stone, Jake E.

    2010-01-01

    This paper examined whether year round schooling (YRS) in California had an effect upon the outcome and growth of schools' Academic Performance Index (API) scores. While many previous studies had examined the connection between YRS and academic achievement, most had lacked the statistical rigour required to provide reliable interpretations. As a…

  2. Propagation container and timing of propagation affects growth and quality of oak seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two experiments were conducted to determine the container effect and the timeline of seed propagation on germination and subsequent shoot and root development for container-grown oaks. Quercus nigra and Q. texana had equal or better growth and better root ratings when acorns were sown in Anderson t...

  3. Stocker growth on rye and ryegrass pastures affects subsequent feedlot gains and carcass traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stocker calves were stocked on annual rye (Secale cereale L.) and ryegrass (Lolium multiflorum Lam.) pastures using stocking strategies (STK) to create graded levels of gain to assess subsequent growth rates, feedlot performance, and carcass traits. During two consecutive years, yearling Angus, Here...

  4. Study of factors affecting growth and cold acclimation of Vitis callus cultures

    SciTech Connect

    Deng, L.

    1987-01-01

    In vitro grape tissue culture initiation, growth, and cold acclimation were studied. Factors involved were genotypes, media, plant growth regulators, age, light, temperature, antioxidant, clearing and adsorbing agents, sucrose level, osmotic potential, ABA, chilling and freezing treatments. Murashige and Skoog (MS) medium containing 1 ..mu..M 2,4-d + 0.1 uM Ba, MS containing 1 uM 2,4-D, and woody plant medium containing 1 uM 2,4-D + 0.1 uM BA produced abundant callus tissue for most grape genotypes; either WPM or MS containing 1 uM BA stimulated shoot growth in all the 12 genotypes tested. Adding 1 uM abscisic acid (ABA) to the B5 medium with 1 uM 2,4-D and 0.5 uM BA enhanced growth and quality of Chancellor callus. /sup 3/H-ABA was taken up actively by callus tissue at 12 days after subculture, but by 20 d this effect disappeared. When /sup 14/C-sucrose was added to the medium. /sup 14/C level of cells reached a plateau after 48 h; this plateau was higher if ABA was also present in the medium. Cells on media containing ABA were larger in size, lighter in color, and more loosely connected.

  5. Vascular flows and transpiration affect peach (Prunus persica Batsch.) fruit daily growth.

    PubMed

    Morandi, Brunella; Rieger, Mark; Grappadelli, Luca Corelli

    2007-01-01

    The relative contributions of xylem, phloem, and transpiration to fruit growth and the daily patterns of their flows have been determined in peach, during the two stages of rapid diameter increase, by precise and continuous monitoring of fruit diameter variations. Xylem, phloem, and transpiration contributions to growth were quantified by comparing the diurnal patterns of diameter change of fruits, which were then girdled and subsequently detached. Xylem supports peach growth by 70%, and phloem 30%, while transpiration accounts for approximately 60% of daily total inflows. These figures and their diurnal patterns were comparable among years, stages, and cultivars. Xylem was functional at both stage I and III, while fruit transpiration was high and strictly dependent on environmental conditions, causing periods of fruit shrinkage. Phloem imports were correlated to fruit shrinkage and appear to facilitate subsequent fruit enlargement. Peach displays a growth mechanism which can be explained on the basis of passive unloading of photoassimilates from the phloem. A pivotal role is played by the large amount of water flowing from the tree to the fruit and from the fruit to the atmosphere.

  6. Factors affecting the growth of Listeria monocytogenes on minimally processed fresh endive.

    PubMed

    Carlin, F; Nguyen-the, C; Abreu da Silva, A

    1995-06-01

    The influence of various factors on the fate of Listeria monocytogenes on cut leaves of broad-leaved endive has been studied. Factors considered were temperature, characteristics of the leaves (age, quantity and quality of the epiphytic microflora) and characteristics of the L. monocytogenes inoculum (concentration, strain). The increases in numbers of L. monocytogenes were lower than those of the aerobic mesophilic microflora at 3 degrees, 6 degrees, 10 degrees and 20 degrees C. Doubling times of the populations of L. monocytogenes were in the same order of magnitude as those of aerobic bacteria at 10 degrees and 20 degrees C, but longer at 3 degrees and 6 degrees C. There were positive significant correlations between growth of L. monocytogenes and populations of aerobic bacteria, and between growth of L. monocytogenes and extent of spoilage on the leaves. Of 225 bacteria isolated from the leaves, 84% were identified as fluorescent pseudomonads; there was no difference in the species isolated from leaves that showed a low growth of L. monocytogenes and leaves that showed a high growth of L. monocytogenes. Populations of L. monocytogenes increased faster during the first 2 and 4 d of storage at 10 degrees C on leaves inoculated with 10-10(3) cfu g-1 than on leaves inoculated with about 10(5) cfu g-1, but the population reached after 7 d was lower. The behaviour of L. monocytogenes was similar among the three strains tested.

  7. The longissimus thoracis muscle proteome in Alentejana bulls as affected by growth path.

    PubMed

    Almeida, André M; Nanni, Paolo; Ferreira, Ana M; Fortes, Claudia; Grossmann, Jonas; Bessa, Rui J B; Costa, Paulo

    2017-01-30

    Beef production is an important economic activity. In Southern Europe there are two types of beef production systems based on growth paths: continuous (CG) versus discontinuous growth (DG). DG is a traditional system dependent on pasture; whereas in CG animals are supplemented on concentrate feed. We compare the protein abundance profiles of the longissimus thoracis (LT) muscle in CG and DG animals using label-free quantitative proteomics. Twenty three Alentejana male calves (9months-old, 239kg live-weight) were allocated to two feeding regimens. In CG (n=12) production system, animals were fed ad libitum on concentrates plus hay and slaughtered at 18months. In DG (n=11) production system, animals were fed ad libitum on hay from 9 to 15months of age and then the same diet provided to the CG group and slaughtered at 24months. The LT muscle was sampled and protein abundance profiles determined using label-free quantification. We identified 510 proteins, of which 26 showed differential abundance. Several proteins (e.g. Myozenin-2, glyoclythic enzymes and 14-3-3 protein zeta/delta) are proposed as indicators of a more intensive growth path. Myosin binding protein H had higher abundance in the DG group, suggesting it could be associated to discontinuous growth path.

  8. Growth of and fumitremorgin production by Neosartorya fischeri as affected by temperature, light, and water activity.

    PubMed Central

    Nielsen, P V; Beuchat, L R; Frisvad, J C

    1988-01-01

    The effects of temperature, light, and water activity (aw) on the growth and fumitremorgin production of a heat-resistant mold, Neosartorya fischeri, cultured on Czapek Yeast Autolysate agar (CYA) were studied for incubation periods of up to 74 days. Colonies were examined visually, and extracts of mycelia and CYA on which the mold was cultured were analyzed for mycotoxin content by high-performance liquid chromatography. Growth always resulted in the production of the tremorgenic mycotoxins verruculogen and fumitremorgins A and C. The optimum temperatures for the production of verruculogen and fumitremorgins A and C on CYA at pH 7.0 were 25, 30, and 37 degrees C, respectively. The production of fumitremorgin C by N. fischeri has not been previously reported. Fumitremorgin production was retarded at 15 degrees C, but an extension of the incubation period resulted in concentrations approaching those observed at 25 degrees C. Light clearly enhanced fumitremorgin production on CYA (pH 7.0, 25 degrees C), but not as dramatically as did the addition of glucose, fructose, or sucrose to CYA growth medium (pH 3.5, 25 degrees C). Growth and fumitremorgin production was greatest at aw of 0.980 on CYA supplemented with glucose or fructose and at aw of 0.990 on CYA supplemented with sucrose. Growth and fumitremorgin production were observed at aw as low as 0.925 on glucose-supplemented CYA but not at aw lower than 0.970 on CYA supplemented with sucrose. Verruculogen was produced in the highest amount on all test media, followed by fumitremorgin A and fumitremorgin C. PMID:3415223

  9. Dietary supplementation of probiotics affects growth, immune response and disease resistance of Cyprinus carpio fry.

    PubMed

    Gupta, Akhil; Gupta, Paromita; Dhawan, Asha

    2014-12-01

    The effects of dietary Bacillus coagulans (MTCC 9872), Bacillus licheniformis (MTCC 6824) and Paenibacillus polymyxa (MTCC 122) supplementation on growth performance, non-specific immunity and protection against Aeromonas hydrophila infection were evaluated in common carp, Cyprinus carpio fry. Laboratory maintained B. coagulans, B. licheniformis and P. polymyxa were used to study antagonistic activity against fish pathogenic bacteria by agar well diffusion assay. Healthy fish fry were challenged by this bacterium for determination of its safety. Fish were fed for 80 days with control basal diet (B0) and experimental diets containing B. coagulans (B1), B. licheniformis (B2) and P. polymyxa (B3) at 10(9) CFU/g diet. Fish fry (mean weight 0.329 ± 0.01 g) were fed these diets and growth performance, various non-specific immune parameters and disease resistance study were conducted at 80 days post-feeding. The antagonism study showed inhibition zone against A. hydrophila and Vibrio harveyi. All the probiotic bacterial strains were harmless to fish fry as neither mortality nor morbidities were observed of the challenge. The growth-promoting influences of probiotic supplemented dietary treatments were observed with fish fry and the optimum survival, growth and feed utilization were obtained with P. polymyxa (B3) supplemented diet. Study of different non-specific innate immunological parameters viz. lysozyme activity, respiratory burst assay and myeloperoxidase content showed significant (p < 0.05) higher values in fish fry fed B3 diet at 10(9) CFU/g. The challenge test showed dietary supplementation of B. coagulans, B. licheniformis and P. polymyxa significantly (p < 0.05) enhanced the resistance of fish fry against bacterial challenge. These results collectively suggests that P. polymyxa is a potential probiotic species and can be used in aquaculture to improve growth, feed utilization, non-specific immune responses and disease resistance of fry common carp, C. carpio.

  10. Effect of Larval Competition on Extrinsic Incubation Period and Vectorial Capacity of Aedes albopictus for Dengue Virus.

    PubMed

    Bara, Jeffrey; Rapti, Zoi; Cáceres, Carla E; Muturi, Ephantus J

    2015-01-01

    Despite the growing awareness that larval competition can influence adult mosquito life history traits including susceptibility to pathogens, the net effect of larval competition on human risk of exposure to mosquito-borne pathogens remains poorly understood. We examined how intraspecific larval competition affects dengue-2 virus (DENV-2) extrinsic incubation period and vectorial capacity of its natural vector Aedes albopictus. Adult Ae. albopictus from low and high-larval density conditions were orally challenged with DENV-2 and then assayed for virus infection and dissemination rates following a 6, 9, or 12-day incubation period using real-time quantitative reverse transcription PCR. We then modeled the effect of larval competition on vectorial capacity using parameter estimates obtained from peer-reviewed field and laboratory studies. Larval competition resulted in significantly longer development times, lower emergence rates, and smaller adults, but did not significantly affect the extrinsic incubation period of DENV-2 in Ae. albopictus. Our vectorial capacity models suggest that the effect of larval competition on adult mosquito longevity likely has a greater influence on vectorial capacity relative to any competition-induced changes in vector competence. Furthermore, we found that large increases in the viral dissemination rate may be necessary to compensate for small competition-induced reductions in daily survivorship. Our results indicate that mosquito populations that experience stress from larval competition are likely to have a reduced vectorial capacity, even when susceptibility to pathogens is enhanced.

  11. Measuring the Affective and Cognitive Growth of Regularly Admitted and Developmental Studies Students Using the "Learning and Study Strategies Inventory" (LASSI).

    ERIC Educational Resources Information Center

    Nist, Sherrie L.; And Others

    1990-01-01

    Investigates the utility and predictive validity of the Learning and Study Strategies Inventory (LASSI) as a means of measuring college students' cognitive and affective growth following a study strategies course. Finds cognitive and affective growth in both regularly admitted and developmental studies students. Finds that LASSI cannot yet be used…

  12. Patchy Distributions of Competitors Affect the Growth of a Clonal Plant When the Competitor Density Is High

    PubMed Central

    Xue, Wei; Huang, Lin; Dong, Bi-Cheng; Zhang, Ming-Xiang; Yu, Fei-Hai

    2013-01-01

    Environments are patchy in not only abiotic factors but also biotic ones. Many studies have examined effects of spatial heterogeneity in abiotic factors such as light, water and nutrients on the growth of clonal plants, but few have tested those in biotic factors. We conducted a greenhouse experiment to examine how patchy distributions of competitors affect the growth of a rhizomatous wetland plant Bolboschoenus planiculmis and whether such effects depend on the density of the competitors. We grew one ramet of B. planiculmis in the center of each of the experimental boxes without competitors (Schoenoplectus triqueter), with a homogeneous distribution of the competitors of low or high density, and with a patchy distribution of the competitors of low or high density. The presence of competitors markedly decreased the growth (biomass, number of ramets, number of tubers and rhizome length) of the B. planiculmis clones. When the density of the competitors was low, the growth of B. planiculmis did not differ significantly between the competitor patches and competitor-free patches. However, when the density of the competitors was high, the growth of B. planiculmis was significantly higher in the competitor-free patches than in the competitor patches. Therefore, B. planiculmis can respond to patchy distributions of competitors by placing more ramets in competition-free patches when the density of competitors is high, but cannot do so when the density of competitors is low. PMID:24205165

  13. Parathyroid Hormone Receptor Type 1/Indian Hedgehog Expression Is Preserved in the Growth Plate of Human Fetuses Affected with Fibroblast Growth Factor Receptor Type 3 Activating Mutations

    PubMed Central

    Cormier, Sarah; Delezoide, Anne-Lise; Benoist-Lasselin, Catherine; Legeai-Mallet, Laurence; Bonaventure, Jacky; Silve, Caroline

    2002-01-01

    The fibroblast growth factor receptor type 3 (FGFR3) and Indian hedgehog (IHH)/parathyroid hormone (PTH)/PTH-related peptide receptor type 1 (PTHR1) systems are both essential regulators of endochondral ossification. Based on mouse models, activation of the FGFR3 system is suggested to regulate the IHH/PTHR1 pathway. To challenge this possible interaction in humans, we analyzed the femoral growth plates from fetuses carrying activating FGFR3 mutations (9 achondroplasia, 21 and 8 thanatophoric dysplasia types 1 and 2, respectively) and 14 age-matched controls by histological techniques and in situ hybridization using riboprobes for human IHH, PTHR1, type 10 and type 1 collagen transcripts. We show that bone-perichondrial ring enlargement and growth plate increased vascularization in FGFR3-mutated fetuses correlate with the phenotypic severity of the disease. PTHR1 and IHH expression in growth plates, bone-perichondrial rings and vascular canals is not affected by FGFR3 mutations, irrespective of the mutant genotype and age, and is in keeping with cell phenotypes. These results indicate that in humans, FGFR3 signaling does not down-regulate the main players of the IHH/PTHR1 pathway. Furthermore, we show that cells within the bone-perichondrial ring in controls and patients express IHH, PTHR1, and type 10 and type 1 collagen transcripts, suggesting that bone-perichondrial ring formation involves cells of both chondrocytic and osteoblastic phenotypes. PMID:12368206

  14. Submerged conidiation and product formation by Aspergillus niger at low specific growth rates are affected in aerial developmental mutants.

    PubMed

    Jørgensen, Thomas R; Nielsen, Kristian F; Arentshorst, Mark; Park, Joohae; van den Hondel, Cees A; Frisvad, Jens C; Ram, Arthur F

    2011-08-01

    Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (ΔfwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B(2), B(4), and B(6) were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ΔfwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic

  15. Watermelon seedling growth and mortality as affected by Anasa tristis (Heteroptera: Coreidae).

    PubMed

    Edelson, J V; Duthie, J; Roberts, W

    2002-06-01

    Adult squash bugs, Anasa tristis (De Geer), were confined on seedling watermelon plants at densities of zero, one, two, and four per plant. Squash bugs were allowed to feed on the plants until plants died or reached 30 cm in height. Number of leaves and length of plant vine were recorded at 2- or 3-d intervals. Seedling foliage, stems, and roots were harvested and dried after plants reached 30 cm in height. Growth of seedlings was regressed on number of squash bugs and results indicated that an increasing density of squash bugs feeding on seedlings resulted in a significant reduction in plant growth. Additionally, increased density of squash bugs resulted in reduced weight of foliage and root dry biomass. Seedling mortality increased as the density of squash bugs increased.

  16. Emerging aquatic insects affect riparian spider distribution and growth rates in a temperate rainforest

    NASA Astrophysics Data System (ADS)

    Marczak, L. B.; Richardson, J. S.

    2005-05-01

    Emerging aquatic insects from streams provide a temporally shifting, alternative source of energy to riparian web-building spiders. The effects of dynamics in aquatic insect emergence on spider distributions are poorly understood. We manipulated the abundance of aquatic insects in riparian forests of British Columbia by excluding aquatic insects using a greenhouse type covering from May through the end of July. In the absence of manipulations, aquatic insect abundance generally peaks in July. The overall density of riparian spiders was reduced when aquatic insects were excluded in May and July but not in June. As in similar studies, tetragnathid spiders in particular showed a strong response to aquatic insect exclusion. The ideal free distribution predicts that organisms at low densities should have equal access to resources for growth to those at high densities. Using comparisons of body size low and high densities of animals we determined that tetragnathid abundance and growth patterns do represent an ideal free distribution.

  17. Factors that affect postnatal bone growth retardation in the twitcher murine model of Krabbe disease.

    PubMed

    Contreras, Miguel Agustin; Ries, William Louis; Shanmugarajan, Srinivasan; Arboleda, Gonzalo; Singh, Inderjit; Singh, Avtar Kaur

    2010-01-01

    Krabbe disease is an inherited lysosomal disorder in which galactosylsphingosine (psychosine) accumulates mainly in the central nervous system. To gain insight into the possible mechanism(s) that may be participating in the inhibition of the postnatal somatic growth described in the animal model of this disease (twitcher mouse, twi), we studied their femora. This study reports that twi femora are smaller than of those of wild type (wt), and present with abnormality of marrow cellularity, bone deposition (osteoblastic function), and osteoclastic activity. Furthermore, lipidomic analysis indicates altered sphingolipid homeostasis, but without significant changes in the levels of sphingolipid-derived intermediates of cell death (ceramide) or the levels of the osteoclast-osteoblast coupling factor (sphingosine-1-phosphate). However, there was significant accumulation of psychosine in the femora of adult twi animals as compared to wt, without induction of tumor necrosis factor-alpha or interleukin-6. Analysis of insulin-like growth factor-1 (IGF-1) plasma levels, a liver secreted hormone known to play a role in bone growth, indicated a drastic reduction in twi animals when compared to wt. To identify the cause of the decrease, we examined the IGF-1 mRNA expression and protein levels in the liver. The results indicated a significant reduction of IGF-1 mRNA as well as protein levels in the liver from twi as compared to wt littermates. Our data suggest that a combination of endogenous (psychosine) and endocrine (IGF-1) factors play a role in the inhibition of postnatal bone growth in twi mice; and further suggest that derangements of liver function may be contributing, at least in part, to this alteration.

  18. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

    USGS Publications Warehouse

    Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

    2008-01-01

    Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

  19. Dietary indispensable amino acids profile affects protein utilization and growth of Senegalese sole larvae.

    PubMed

    Canada, Paula; Engrola, Sofia; Richard, Nadège; Lopes, Ana Filipa; Pinto, Wilson; Valente, Luísa M P; Conceição, Luís E C

    2016-12-01

    In diet formulation for fish, it is critical to assure that all the indispensable amino acids (IAA) are available in the right quantities and ratios. This will allow minimizing dietary AA imbalances that will result in unavoidable AA losses for energy dissipation rather than for protein synthesis and growth. The supplementation with crystalline amino acids (CAA) is a possible solution to correct the dietary amino acid (AA) profile that has shown positive results for larvae of some fish species. This study tested the effect of supplementing a practical microdiet with encapsulated CAA as to balance the dietary IAA profile and to improve the capacity of Senegalese sole larvae to utilize AA and maximize growth potential. Larvae were reared at 19 °C under a co-feeding regime from mouth opening. Two microdiets were formulated and processed as to have as much as possible the same ingredients and proximate composition. The control diet (CTRL) formulation was based on commonly used protein sources. A balanced diet (BAL) was formulated as to meet the ideal IAA profile defined for Senegalese sole: the dietary AA profile was corrected by replacing 4 % of encapsulated protein hydrolysate by CAA. The in vivo method of controlled tube-feeding was used to assess the effect on the larvae capacity to utilize protein, during key developmental stages. Growth was monitored until 51 DAH. The supplementation of microdiets with CAA in order to balance the dietary AA had a positive short-term effect on the Senegalese sole larvae capacity to retain protein. However, that did not translate into increased growth. On the contrary, larvae fed a more imbalanced (CTRL group) diet attained a better performance. Further studies are needed to ascertain whether this was due to an effect on the voluntary feed intake as a compensatory response to the dietary IAA imbalance in the CTRL diet or due to the higher content of tryptophan in the BAL diet.

  20. Infrared warming affects intrarow soil carbon dioxide efflux during early vegetative growth of spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global warming will likely affect carbon cycles in agricultural soils. Our objective was to deploy infrared (IR) warming to characterize the effect of global warming on soil temperature (Ts), volumetric soil-water content ('s), and intrarow soil CO2 efflux (Fs) of an open-field spring wheat (Triticu...

  1. Complex inter-Kingdom interactions: carnivorous plants affect growth of an aquatic vertebrate.

    PubMed

    Davenport, Jon M; Riley, Alex W

    2017-05-01

    Coexistence of organisms in nature is more likely when phenotypic similarities of individuals are reduced. Despite the lack of similarity, distantly related taxa still compete intensely for shared resources. No larger difference between organisms that share a common prey could exist than between carnivorous plants and animals. However, few studies have considered inter-Kingdom competition among carnivorous plants and animals. In order to evaluate interactions between a carnivorous plant (greater bladderwort, Utricularia vulgaris) and a vertebrate (bluegill, Lepomis macrochirus) on a shared prey (zooplankton), we conducted a mesocosm experiment. We deployed two levels of bladderwort presence (functional and crushed) and measured bluegill responses (survival and growth). Zooplankton abundance was reduced the greatest in bluegill and functional bladderwort treatments. Bluegill survival did not differ among treatments, but growth was greatest with crushed bladderwort. Thus, bluegill growth was facilitated by reducing interference competition in the presence of crushed bladderwort. The facilitating effect was dampened, however, when functional bladderwort removed a shared prey. To our knowledge, this is one of the first studies to experimentally demonstrate interactions between a carnivorous plant and a fish. Our data suggest that carnivorous plants may actively promote or reduce animal co-occurrence from some ecosystems via facilitation or competition.

  2. How microRNA172 affects fruit growth in different species is dependent on fruit type.

    PubMed

    Yao, Jia-Long; Tomes, Sumathi; Xu, Juan; Gleave, Andrew P

    2016-01-01

    microRNA172 (miR172) expression has been shown to have a positive effect on Arabidopsis fruit (siliques) growth. In contrast, over-expression of miR172 has a negative influence on fruit growth in apple, resulting in a dramatic reduction in fruit size. This negative influence is supported by the results of analyzing a transposable element (TE) insertional allele of a MIR172 gene that has reduced expression of the miRNA and is associated with an increase in fruit size. Arabidopsis siliques are a dry fruit derived from ovary tissues, whereas apple is a fleshy pome fruit derived mostly from hypanthium tissues. A model has been developed to explain the contrasting impact of miR172 expression in these two plant species based on the differences in their fruit structure. Transgenic apple plants with extremely high levels of miR172 overexpression produced flowers consisting of carpel tissues only, which failed to produce fruit. By comparison, in tomato, a fleshy berry fruit derived from the ovary, high level over-expression of the same miR172 resulted in carpel-only flowers which developed into parthenocarpic fruit. These results further indicate that the influence of miR172 on fruit growth in different plant species depends on its fruit type.

  3. Integration of Ethylene and Light Signaling Affects Hypocotyl Growth in Arabidopsis

    PubMed Central

    Yu, Yanwen; Huang, Rongfeng

    2017-01-01

    As an ideal model for studying ethylene effects on cell elongation, Arabidopsis hypocotyl growth is widely used due to the unique characteristic that ethylene stimulates hypocotyl elongation in the light but inhibits it in the dark. Although the contrasting effect of ethylene on hypocotyl growth has long been known, the molecular basis of this effect has only gradually been identified in recent years. In the light, ethylene promotes the expression of PHYTOCHROME INTERACTING FACTOR 3 (PIF3) and the degradation of ELONGATED HYPOCOTYL 5 (HY5) protein, thus stimulating hypocotyl growth. In the dark, ETHYLENE RESPONSE FACTOR 1 (ERF1) and WAVE-DAMPENED 5 (WDL5) induced by ethylene are responsible for its inhibitory effect on hypocotyl elongation. Moreover, CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and PHYTOCHROME B (phyB) mediate the light-suppressed ethylene response in different ways. Here, we review several pivotal advances associated with ethylene-regulated hypocotyl elongation, focusing on the integration of ethylene and light signaling during seedling emergence from the soil. PMID:28174592

  4. Candida albicans survival, growth and biofilm formation are differently affected by mouthwashes: an in vitro study.

    PubMed

    Paulone, Simona; Malavasi, Giulia; Ardizzoni, Andrea; Orsi, Carlotta Francesca; Peppoloni, Samuele; Neglia, Rachele Giovanna; Blasi, Elisabetta

    2017-01-01

    Candida albicans is the most common cause of oral mycoses. The aim of the present study was to investigate in vitro the susceptibility of C. albicans to mouthwashes, in terms of growth, survival and biofilm formation. Candida albicans, laboratory strain SC5314, and 7 commercial mouthwashes were employed: 3 with 0.2% chlorhexidine digluconate; 1 with 0.06% chlorhexidine digluconate and 250 ppm F- sodium fluoride; 3 with fluorine-containing molecules. None of the mouthwashes contained ethanol in their formulations. The anti-Candida effects of the mouthwashes were assessed by disk diffusion, crystal violet and XTT assays. By using five protocols combining different dilutions and contact times the mouthwashes were tested against: 1) C. albicans growth; 2) biofilm formation; 3) survival of fungal cells in early, developing and mature Candida biofilm. Chlorhexidine digluconate-containing mouthwashes consistently exhibited the highest anti-Candida activity, irrespective of the protocols employed. Fungal growth, biofilm formation and survival of Candida cells within biofilm were impaired, the effects strictly depending on both the dilution employed and the time of contact. These in vitro studies provide evidence that mouthwashes exert anti-Candida activity against both planktonic and biofilm fungal structures, but to a different extent depending on their composition. This suggests special caution in the choice of mouthwashes for oral hygiene, whether aimed at prevention or treatment of oral candidiasis.

  5. NIMA-related kinase NEK6 affects plant growth and stress response in Arabidopsis.

    PubMed

    Zhang, Bo; Chen, Hao-Wei; Mu, Rui-Ling; Zhang, Wang-Ke; Zhao, Ming-Yu; Wei, Wei; Wang, Fang; Yu, Hui; Lei, Gang; Zou, Hong-Feng; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

    2011-12-01

    The NIMA-related kinases (NEKs) are a family of serine/threonine kinases involved largely in cell cycle control in fungi, mammals and other eukaryotes. In Arabidopsis, NEK6 is involved in the regulation of epidermal cell morphogenesis. However, other roles of NEK6 in plants are less well understood. Here we report functions of NEK6 in plant growth, development and stress responses in Arabidopsis. NEK6 transcripts and proteins are induced by ethylene precursor ACC and salt stress. Expression of other NEK genes except NEK5 is also responsive to the two treatments. Overexpression and mutant analysis disclose that the NEK6 gene increases rosette growth, seed yield and lateral root formation. However, NEK6 appears to play a negative role in the control of seed size. The gene also promotes plant tolerance to salt stress and osmotic stress in its overexpressing plants. The NEK6 gene may achieve its function through suppression of ethylene biosynthesis and activation of CYCB1;1 and CYCA3;1 expression. Our present study reveals new functions of the NEK6 gene in plant growth and stress tolerance, and manipulation of NEK6 may improve important agronomic traits in crop plants.

  6. Conditions affecting growth and developmental competence of mammalian oocytes in vitro.

    PubMed

    Hirao, Yuji

    2011-04-01

    Mammalian ovaries contain a large number of oocytes at different stages of growth. To utilize potential female gametes, it is important to develop culture systems that permit oocytes to achieve full growth and competence in order to undergo maturation, fertilization and development. The desired culture systems should meet at least the following three conditions: (i) oocytes remain healthy and functional so that they can execute intrinsic programs that direct their growth and development; (ii) granulosa cells that are adjacent to oocytes proliferate efficiently to prevent oocytes from becoming denuded; and (iii) granulosa cells maintain (and develop) appropriate associations with oocytes during the culture period. For this reason, several systems have been developed, and they can be classified into four categories based on the structure and components of the follicle/oocyte-granulosa cell complex and the location of the oocyte in the physical organization of the complex. The resultant diverse morphologies are due to multiple factors, including the method for initial isolation of follicles, the culture substrate, and hormones and other factors added into the medium. It is important to find an optimal combination of such factors involved in the process to facilitate future research efforts.

  7. Association with pathogenic bacteria affects life-history traits and population growth in Caenorhabditis elegans.

    PubMed

    Diaz, S Anaid; Mooring, Eric Q; Rens, Elisabeth G; Restif, Olivier

    2015-04-01

    Determining the relationship between individual life-history traits and population dynamics is an essential step to understand and predict natural selection. Model organisms that can be conveniently studied experimentally at both levels are invaluable to test the rich body of theoretical literature in this area. The nematode Caenorhabditis elegans, despite being a well-established workhorse in genetics, has only recently received attention from ecologists and evolutionary biologists, especially with respect to its association with pathogenic bacteria. In order to start filling the gap between the two areas, we conducted a series of experiments aiming at measuring life-history traits as well as population growth of C. elegans in response to three different bacterial strains: Escherichia coli OP50, Salmonella enterica Typhimurium, and Pseudomonas aeruginosa PAO1. Whereas previous studies had established that the latter two reduced the survival of nematodes feeding on them compared to E. coli OP50, we report for the first time an enhancement in reproductive success and population growth for worms feeding on S. enterica Typhimurium. Furthermore, we used an age-specific population dynamic model, parameterized using individual life-history assays, to successfully predict the growth of populations over three generations. This study paves the way for more detailed and quantitative experimental investigation of the ecology and evolution of C. elegans and the bacteria it interacts with, which could improve our understanding of the fate of opportunistic pathogens in the environment.

  8. How microRNA172 affects fruit growth in different species is dependent on fruit type

    PubMed Central

    Yao, Jia-Long; Tomes, Sumathi; Xu, Juan; Gleave, Andrew P.

    2016-01-01

    ABSTRACT microRNA172 (miR172) expression has been shown to have a positive effect on Arabidopsis fruit (siliques) growth. In contrast, over-expression of miR172 has a negative influence on fruit growth in apple, resulting in a dramatic reduction in fruit size. This negative influence is supported by the results of analyzing a transposable element (TE) insertional allele of a MIR172 gene that has reduced expression of the miRNA and is associated with an increase in fruit size. Arabidopsis siliques are a dry fruit derived from ovary tissues, whereas apple is a fleshy pome fruit derived mostly from hypanthium tissues. A model has been developed to explain the contrasting impact of miR172 expression in these two plant species based on the differences in their fruit structure. Transgenic apple plants with extremely high levels of miR172 overexpression produced flowers consisting of carpel tissues only, which failed to produce fruit. By comparison, in tomato, a fleshy berry fruit derived from the ovary, high level over-expression of the same miR172 resulted in carpel-only flowers which developed into parthenocarpic fruit. These results further indicate that the influence of miR172 on fruit growth in different plant species depends on its fruit type. PMID:26926448

  9. Carboxyl-modified single-walled carbon nanotubes negatively affect bacterial growth and denitrification activity

    NASA Astrophysics Data System (ADS)

    Zheng, Xiong; Su, Yinglong; Chen, Yinguang; Wan, Rui; Li, Mu; Wei, Yuanyuan; Huang, Haining

    2014-07-01

    Single-walled carbon nanotubes (SWNTs) have been used in a wide range of fields, and the surface modification via carboxyl functionalization can further improve their physicochemical properties. However, whether carboxyl-modified SWNT poses potential risks to microbial denitrification after its release into the environment remains unknown. Here we present the possible effects of carboxyl-modified SWNT on the growth and denitrification activity of Paracoccus denitrificans (a model denitrifying bacterium). It was found that carboxyl-modified SWNT were present both outside and inside the bacteria, and thus induced bacterial growth inhibition at the concentrations of 10 and 50 mg/L. After 24 h of exposure, the final nitrate concentration in the presence of 50 mg/L carboxyl-modified SWNT was 21-fold higher than that in its absence, indicating that nitrate reduction was substantially suppressed by carboxyl-modified SWNT. The transcriptional profiling revealed that carboxyl-modified SWNT led to the transcriptional activation of the genes encoding ribonucleotide reductase in response to DNA damage and also decreased the gene expressions involved in glucose metabolism and energy production, which was an important reason for bacterial growth inhibition. Moreover, carboxyl-modified SWNT caused the significant down-regulation and lower activity of nitrate reductase, which was consistent with the decreased efficiency of nitrate reduction.

  10. Maternal stress affects postnatal growth and the pituitary expression of prolactin in mouse offspring.

    PubMed

    Gao, Pengfei; Ishige, Atsushi; Murakami, Yu; Nakata, Hideyuki; Oka, Jun-Ichiro; Munakata, Kaori; Yamamoto, Masahiro; Nishimura, Ko; Watanabe, Kenji

    2011-03-01

    Maternal stress exerts long-lasting psychiatric and somatic on offspring, which persist into adulthood. However, the effect of maternal stress on the postnatal growth of pups has not been widely reported. In this study, we found that maternal immobilization stress (IS) during lactation resulted in low body weight of male mouse offspring, which persisted after weaning. Despite free access to chow, IS induced maternal malnutrition and decreased the serum insulin-like growth factor-1 (IGF-1) levels in the mothers and in the pups. mRNA expression analysis of anterior pituitary hormones in the pups revealed that growth hormone (GH) and prolactin (PRL), but no other hormones, were decreased by IS. Expression of the pituitary transcription factor PIT1 and isoforms of PITX2, which are essential for the development and function of GH-producing somatotropes and PRL-producing lactotropes, was decreased, whereas that of PROP1, which is critical for the earlier stages of pituitary development, was unchanged. Immunohistochemistry also showed a decrease in pituitary PRL protein expression. These results suggest that stress in a postpartum mother has persistent effects on the body weight of the offspring. Reduced PRL expression in the offspring's pituitary gland may play a role in these effects.

  11. Insights into Embryo Defenses of the Invasive Apple Snail Pomacea canaliculata: Egg Mass Ingestion Affects Rat Intestine Morphology and Growth

    PubMed Central

    Gimeno, Eduardo J.; Heras, Horacio

    2014-01-01

    Background The spread of the invasive snail Pomacea canaliculata is expanding the rat lungworm disease beyond its native range. Their toxic eggs have virtually no predators and unusual defenses including a neurotoxic lectin and a proteinase inhibitor, presumably advertised by a warning coloration. We explored the effect of egg perivitellin fluid (PVF) ingestion on the rat small intestine morphology and physiology. Methodology/Principal Findings Through a combination of biochemical, histochemical, histopathological, scanning electron microscopy, cell culture and feeding experiments, we analyzed intestinal morphology, growth rate, hemaglutinating activity, cytotoxicity and cell proliferation after oral administration of PVF to rats. PVF adversely affects small intestine metabolism and morphology and consequently the standard growth rate, presumably by lectin-like proteins, as suggested by PVF hemaglutinating activity and its cytotoxic effect on Caco-2 cell culture. Short-term effects of ingested PVF were studied in growing rats. PVF-supplemented diet induced the appearance of shorter and wider villi as well as fused villi. This was associated with changes in glycoconjugate expression, increased cell proliferation at crypt base, and hypertrophic mucosal growth. This resulted in a decreased absorptive surface after 3 days of treatment and a diminished rat growth rate that reverted to normal after the fourth day of treatment. Longer exposure to PVF induced a time-dependent lengthening of the small intestine while switching to a control diet restored intestine length and morphology after 4 days. Conclusions/Significance Ingestion of PVF rapidly limits the ability of potential predators to absorb nutrients by inducing large, reversible changes in intestinal morphology and growth rate. The occurrence of toxins that affect intestinal morphology and absorption is a strategy against predation not recognized among animals before. Remarkably, this defense is rather similar to

  12. The Garlic Allelochemical Diallyl Disulfide Affects Tomato Root Growth by Influencing Cell Division, Phytohormone Balance and Expansin Gene Expression

    PubMed Central

    Cheng, Fang; Cheng, Zhihui; Meng, Huanwen; Tang, Xiangwei

    2016-01-01

    Diallyl disulfide (DADS) is a volatile organosulfur compound derived from garlic (Allium sativum L.), and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L.) seed germination, root growth, mitotic index, and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs), auxin transport genes (SlPINs), and expansin genes (EXPs) in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01–0.62 mM) of DADS significantly promoted root growth, whereas higher levels (6.20–20.67 mM) showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM). This result suggests that tomato root growth may be

  13. Ontogenetic effects of diet during early development on growth performance, myosin mRNA expression and metabolic enzyme activity in Atlantic cod juveniles reared at different salinities.

    PubMed

    Koedijk, Roland M; Le François, Nathalie R; Blier, Pierre U; Foss, Atle; Folkvord, Arild; Ditlecadet, Delphine; Lamarre, Simon G; Stefansson, Sigurd O; Imsland, Albert K

    2010-05-01

    This study investigates the effect of diet during early development on growth and metabolic capacity in the juvenile stage of Atlantic cod. Growth in three groups of Atlantic cod juveniles (10-70 g) was measured at two salinities (15 per thousand or 32 per thousand) in combination with two temperatures (10 degrees C or 14 degrees C). Groups of cod from a single egg batch differed by having been fed with rotifers (R) or natural zooplankton (Z) during the first 36 days post hatch. A third group was fed zooplankton from 1 to 22 dph, after which diet changed to rotifers from 22 to 36 dph (ZRZ). All fish were weaned at 36 dph. Juveniles from the Z and ZRZ groups performed equally well under all experimental conditions, but fish that had received rotifers as a larval diet showed overall significantly lower growth rates. Growth was significantly enhanced by reduced salinity. Metabolic enzyme activity and relative myosin mRNA expression levels were not affected by larval diet. Muscle AAT and MDH were affected by salinity while these enzymes in liver tissue were affected by the interaction between salinity and temperature. Metabolic enzymes were stronger correlated with fish size than growth rates. Our results indicate that larval diet has a pronounced effect on juvenile growth rates under varying environmental conditions as optimal larval diet (zooplankton) increased juvenile growth rates significantly. Metabolic enzyme activity and relative myosin mRNA expression were not affected by larval history, which suggests that the persisting juvenile growth difference is not a result of differing metabolic capacity.

  14. Thermal manipulation during embryogenesis affects myoblast proliferation and skeletal muscle growth in meat-type chickens.

    PubMed

    Piestun, Yogev; Yahav, Shlomo; Halevy, Orna

    2015-10-01

    Thermal manipulation (TM) of 39.5°C applied during mid-embryogenesis (embryonic d 7 to 16) has been proven to promote muscle development and enhance muscle growth and meat production in meat-type chickens. This study aimed to elucidate the cellular basis for this effect. Continuous TM or intermittent TM (for 12 h/d) increased myoblast proliferation manifested by higher (25 to 48%) myoblast number in the pectoral muscles during embryonic development but also during the first week posthatch. Proliferation ability of the pectoral-muscle-derived myoblasts in vitro was significantly higher in the TM treatments until embryonic d 15 (intermittent TM) or 13 (continuous TM) compared to that of controls, suggesting increased myogenic progeny reservoir in the muscle. However, the proliferation ability of myoblasts was lower in the TM treatments vs. control during the last days of incubation. This coincided with higher levels of myogenin expression in the muscle, indicating enhanced cell differentiation in the TM muscle. A similar pattern was observed posthatch: Myoblast proliferation was significantly higher in the TM chicks relative to controls during the peak of posthatch cell proliferation until d 6, followed by lower cell number 2 wk posthatch as myoblast number sharply decreases. Higher myogenin expression was observed in the TM chicks on d 6. This resulted in increased muscle growth, manifested by significantly higher relative weight of breast muscle in the embryo and posthatch. It can be concluded that temperature elevation during mid-term embryogenesis promotes myoblast proliferation, thus increasing myogenic progeny reservoir in the muscle, resulting in enhanced muscle growth in the embryo and posthatch.

  15. TERE1, a novel gene affecting growth regulation in prostate carcinoma.

    PubMed

    McGarvey, Terence W; Nguyen, Trang; Puthiyaveettil, Raghunath; Tomaszewski, John E; Malkowicz, S Bruce

    2003-02-01

    Recently, we isolated a ubiquitously expressed gene designated TERE1, which has a significant effect on the growth regulation in bladder cancer. The TERE1 gene maps to chromosome 1p36.11-1p36.33 between the micro-satellite markers D1S2667 and D1S434, a chromosome locus that has been identified by loss of heterozygosity studies as a site of a putative tumor suppressor gene or genes for multiple tumor types including prostate carcinoma. The expression of the TERE1 transcript and protein was examined in a series of thirty microdissected prostate tumors by semi-quantitative RT/PCR and immunohistochemistry. There was a significant 61% decrease in the TERE1 transcript in prostate carcinoma (CaP) and a distinct loss of the TERE1 protein in metstatic prostate. Though a loss of heterozygosity at chromosome 1p36 was found in 25% of these prostate tumors, there appeared to be no TERE1 mutations present in these tumor samples. Induced TERE1 expression after transduction or transfection of TERE1 constructs into two prostate carcinoma (LNCaP and PC-3) cell lines significantly decreased proliferation up to 80% with a significant increase in the number of cells in G1. Serum factors but not DHT (dihydrotestosterone) appear to regulate the amount of TERE1 protein in the androgen responsive LNCaP cell line. Additionally, we have identified by microarray analysis various growth regulatory genes that are down-regulated or up-regulated in TERE1-transduced PC-3 cells. Altogether, these data suggest that TERE1 maybe significant in prostate cancer growth regulation and the down regulation or absence of TERE1 may be an important component of the phenotype of advanced disease.

  16. Rice LGD1 containing RNA binding activity affects growth and development through alternative promoters.

    PubMed

    Thangasamy, Saminathan; Chen, Pei-Wei; Lai, Ming-Hsing; Chen, Jychian; Jauh, Guang-Yuh

    2012-07-01

    Tiller initiation and panicle development are important agronomical traits for grain production in Oryza sativa L. (rice), but their regulatory mechanisms are not yet fully understood. In this study, T-DNA mutant and RNAi transgenic approaches were used to functionally characterize a unique rice gene, LAGGING GROWTH AND DEVELOPMENT 1 (LGD1). The lgd1 mutant showed slow growth, reduced tiller number and plant height, altered panicle architecture and reduced grain yield. The fewer unelongated internodes and cells in lgd1 led to respective reductions in tiller number and to semi-dwarfism. Several independent LGD1-RNAi lines exhibited defective phenotypes similar to those observed in lgd1. Interestingly, LGD1 encodes multiple transcripts with different transcription start sites (TSSs), which were validated by RNA ligase-mediated rapid amplification of 5' and 3' cDNA ends (RLM-RACE). Additionally, GUS assays and a luciferase promoter assay confirmed the promoter activities of LGD1.1 and LGD1.5. LGD1 encoding a von Willebrand factor type A (vWA) domain containing protein is a single gene in rice that is seemingly specific to grasses. GFP-tagged LGD1 isoforms were predominantly detected in the nucleus, and weakly in the cytoplasm. In vitro northwestern analysis showed the RNA-binding activity of the recombinant C-terminal LGD1 protein. Our results demonstrated that LGD1 pleiotropically regulated rice vegetative growth and development through both the distinct spatiotemporal expression patterns of its multiple transcripts and RNA binding activity. Hence, the study of LGD1 will strengthen our understanding of the molecular basis of the multiple transcripts, and their corresponding polypeptides with RNA binding activity, that regulate pleiotropic effects in rice.

  17. Deiodinase knockdown during early zebrafish development affects growth, development, energy metabolism, motility and phototransduction.

    PubMed

    Bagci, Enise; Heijlen, Marjolein; Vergauwen, Lucia; Hagenaars, An; Houbrechts, Anne M; Esguerra, Camila V; Blust, Ronny; Darras, Veerle M; Knapen, Dries

    2015-01-01

    Thyroid hormone (TH) balance is essential for vertebrate development. Deiodinase type 1 (D1) and type 2 (D2) increase and deiodinase type 3 (D3) decreases local intracellular levels of T3, the most important active TH. The role of deiodinase-mediated TH effects in early vertebrate development is only partially understood. Therefore, we investigated the role of deiodinases during early development of zebrafish until 96 hours post fertilization at the level of the transcriptome (microarray), biochemistry, morphology and physiology using morpholino (MO) knockdown. Knockdown of D1+D2 (D1D2MO) and knockdown of D3 (D3MO) both resulted in transcriptional regulation of energy metabolism and (muscle) development in abdomen and tail, together with reduced growth, impaired swim bladder inflation, reduced protein content and reduced motility. The reduced growth and impaired swim bladder inflation in D1D2MO could be due to lower levels of T3 which is known to drive growth and development. The pronounced upregulation of a large number of transcripts coding for key proteins in ATP-producing pathways in D1D2MO could reflect a compensatory response to a decreased metabolic rate, also typically linked to hypothyroidism. Compared to D1D2MO, the effects were more pronounced or more frequent in D3MO, in which hyperthyroidism is expected. More specifically, increased heart rate, delayed hatching and increased carbohydrate content were observed only in D3MO. An increase of the metabolic rate, a decrease of the metabolic efficiency and a stimulation of gluconeogenesis using amino acids as substrates may have been involved in the observed reduced protein content, growth and motility in D3MO larvae. Furthermore, expression of transcripts involved in purine metabolism coupled to vision was decreased in both knockdown conditions, suggesting that both may impair vision. This study provides new insights, not only into the role of deiodinases, but also into the importance of a correct TH balance

  18. Lichen physiological traits and growth forms affect communities of associated invertebrates.

    PubMed

    Bokhorst, Stef; Asplund, Johan; Kardol, Paul; Wardle, David A

    2015-09-01

    While there has been much interest in the relationships between traits of primary producers and composition of associated invertebrate consumer communities, our knowledge is largely based on studies from vascular plants, while other types of functionally important producers, such as lichens, have rarely been considered. To address how physiological traits of lichens drive community composition of invertebrates, we collected thalli from 27 lichen species from southern Norway and quantified the communities of associated springtails, mites, and nematodes. For each lichen species, we measured key physiological thallus traits and determined whether invertebrate communities were correlated with these traits. We also explored whether invertebrate communities differed among lichen groups, categorized according to nitrogen-fixing ability, growth form, and substratum. Lichen traits explained up to 39% of the variation in abundances of major invertebrate groups. For many invertebrate groups, abundance was positively correlated with lichen N and P concentrations, N:P ratio, and the percentage of water content on saturation (WC), but had few relationships with concentrations of carbon-based secondary compounds. Diversity and taxonomic richness of invertebrate groups were sometimes also correlated with lichen N and N:P ratios. Nitrogen-fixing lichens showed higher abundance and diversity of some invertebrate groups than did non-N-fixing lichens. However, this emerged in part because most N-fixing lichens have a foliose growth form that benefits invertebrates, through, improving the microclimate, independently of N concentration. Furthermore, invertebrate communities associated with terricolous lichens were determined more by their close proximity to the soil invertebrate pool than by lichen traits. Overall, our results reveal that differences between lichen species have a large impact on the invertebrate communities that live among the thalli. Different invertebrate groups show

  19. Inbreeding Effects in Families of Ostrinia nubilalis (Lepidoptera: Crambidae): Larval Development in Laboratory Bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inbreeding depression of laboratory-reared insects has the potential to affect their larval performance and reproductive output. Two studies of laboratory-reared colonies of Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae) were conducted to assess whether inbreeding affected a laboratory bioass...

  20. The Drosophila Transcription Factor Dimmed Affects Neuronal Growth and Differentiation in Multiple Ways Depending on Neuron Type and Developmental Stage

    PubMed Central

    Liu, Yiting; Luo, Jiangnan; Nässel, Dick R.

    2016-01-01

    Growth of postmitotic neurons occurs during different stages of development, including metamorphosis, and may also be part of neuronal plasticity and regeneration. Recently we showed that growth of post-mitotic neuroendocrine cells expressing the basic helix loop helix (bHLH) transcription factor Dimmed (Dimm) in Drosophila could be regulated by insulin/IGF signaling and the insulin receptor (dInR). Dimm is also known to confer a secretory phenotype to neuroendocrine cells and can be part of a combinatorial code specifying terminal differentiation in peptidergic neurons. To further understand the mechanisms of Dimm function we ectopically expressed Dimm or Dimm together with dInR in a wide range of Dimm positive and Dimm negative peptidergic neurons, sensory neurons, interneurons, motor neurons, and gut endocrine cells. We provide further evidence that dInR mediated cell growth occurs in a Dimm dependent manner and that one source of insulin-like peptide (DILP) for dInR mediated cell growth in the CNS is DILP6 from glial cells. Expressing both Dimm and dInR in Dimm negative neurons induced growth of cell bodies, whereas dInR alone did not. We also found that Dimm alone can regulate cell growth depending on specific cell type. This may be explained by the finding that the dInR is a direct target of Dimm. Conditional gene targeting experiments showed that Dimm alone could affect cell growth in certain neuron types during metamorphosis or in the adult stage. Another important finding was that ectopic Dimm inhibits apoptosis of several types of neurons normally destined for programmed cell death (PCD). Taken together our results suggest that Dimm plays multiple transcriptional roles at different developmental stages in a cell type-specific manner. In some cell types ectopic Dimm may act together with resident combinatorial code transcription factors and affect terminal differentiation, as well as act in transcriptional networks that participate in long term maintenance

  1. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death.

    PubMed

    Colangelo, Michele; Camarero, Jesús J; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

    2017-01-01

    Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees.

  2. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death

    PubMed Central

    Colangelo, Michele; Camarero, Jesús J.; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

    2017-01-01

    Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees. PMID:28270816

  3. Feed and feeding regime affect growth rate and gonadosomatic index of adult zebrafish (Danio rerio).

    PubMed

    Gonzales, John M; Law, Sheran Hiu Wan

    2013-12-01

    A 5-week study was conducted to evaluate commercially available Artemia, Ziegler zebrafish diet, and Calamac diet fed in five different feeding regimes on the growth and reproductive development of 7-month-old zebrafish. Zebrafish were fed to satiation three times daily during the normal work week and twice daily during the weekend and holidays. Zebrafish in dietary groups CCC (Calamac three times daily) and CCA (Calamac twice daily, Artemia once daily) had a significantly (p<0.05) greater weight gain and specific growth rate as compared to all other dietary groups. Male zebrafish in dietary group 5 had significantly larger gonadosomatic index (GSI) values than all other groups, while female zebrafish in dietary group CCC had significantly larger GSI values than all other groups. No differences in the fatty acid content of female gonads were detected. Zebrafish fed solely Artemia had the greatest weight loss and lowest GSI values. Preliminary evidence of protein sparing in zebrafish is reported. Collectively, this study sheds more light into the effects of the use of commercially available feeds and feeding regime on the rearing of zebrafish.

  4. A near-null magnetic field affects cryptochrome-related hypocotyl growth and flowering in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Xu, Chunxiao; Yin, Xiao; Lv, Yan; Wu, Changzhe; Zhang, Yuxia; Song, Tao

    2012-03-01

    The blue light receptor, cryptochrome, has been suggested to act as a magnetoreceptor based on the proposition that photochemical reactions are involved in sensing the geomagnetic field. But the effects of the geomagnetic field on cryptochrome remain unclear. Although the functions of cryptochrome have been well demonstrated for Arabidopsis, the effect of the geomagnetic field on the growth of Arabidopsis and its mechanism of action are poorly understood. We eliminated the local geomagnetic field to grow Arabidopsis in a near-null magnetic field and found that the inhibition of Arabidopsis hypocotyl growth by white light was weakened, and flowering time was delayed. The expressions of three cryptochrome-signaling-related genes, PHYB, CO and FT also changed; the transcript level of PHYB was elevated ca. 40%, and that of CO and FT was reduced ca. 40% and 50%, respectively. These data suggest that the effects of a near-null magnetic field on Arabidopsis are cryptochrome-related, which may be revealed by a modification of the active state of cryptochrome and the subsequent signaling cascade.

  5. Molecular analyses of nuclear-cytoplasmic interactions affecting plant growth and yield. Final technical report

    SciTech Connect

    Newton, K.J.

    1998-11-01

    Mitochondria have a central role in the production of cellular energy. The biogenesis and functioning of mitochondria depends on the expression of both mitochondrial and nuclear genes. One approach to investigating the role of nuclear-mitochondrial cooperation in plant growth and development is to identify combinations of nuclear and mitochondrial genomes that result in altered but sublethal phenotypes. Plants that have certain maize nuclear genotypes in combination with cytoplasmic genomes from more distantly-related teosintes can exhibit incompatible phenotypes, such as reduced plant growth and yield and cytoplasmic male sterility, as well as altered mitochondrial gene expression. The characterization of these nuclear-cytoplasmic interactions was the focus of this grant. The authors were investigating the effects of two maize nuclear genes, RcmI and Mct, on mitochondrial function and gene expression. Plants with the teosinte cytoplasms and homozygous for the recessive rcm allele are small (miniature) and-slow-growing and the kernels are reduced in size. The authors mapped this locus to molecular markers on chromosome 7 and attempted to clone this locus by transposon tagging. The effects of the nuclear-cytoplasmic interaction on mitochondrial function and mitochondrial protein profiles were also studied.

  6. Delayed soil thawing affects root and shoot functioning and growth in Scots pine.

    PubMed

    Repo, Tapani; Lehto, Tarja; Finér, Leena

    2008-10-01

    In boreal regions, soil can remain frozen after the start of the growing season. We compared relationships between root characteristics and water relations in Scots pine (Pinus sylvestris L.) saplings subjected to soil frost treatments before and during the first week of the growing period in a controlled environment experiment. Delayed soil thawing delayed the onset of sap flow or totally blocked it if soil thawing lagged the start of the growing period by 7 days. This effect was reflected in the electrical impedance of needles and trunks and in the relative electrolyte leakage of needles. Prolonged soil frost reduced or completely inhibited root growth. In unfrozen soil, limited trunk sap flow was observed despite unfavorable aboveground growing conditions (low temperature, low irradiance, short photoperiod). Following the earliest soil thaw, sap flow varied during the growing season, depending on light and temperature conditions, phenological stage of the plant and the amount of live needles in the canopy. The results suggest that delayed soil thawing can reduce tree growth, and if prolonged, it can be lethal.

  7. Expression of a calmodulin methylation mutant affects the growth and development of transgenic tobacco plants.

    PubMed Central

    Roberts, D M; Besl, L; Oh, S H; Masterson, R V; Schell, J; Stacey, G

    1992-01-01

    Transgenic plants were constructed that express two foreign calmodulins (VU-1 and VU-3 calmodulins) derived from a cloned synthetic calmodulin gene. VU-1 calmodulin, similar to endogenous plant calmodulin, possesses a lysine residue at position 115 and undergoes posttranslational methylation. VU-3 calmodulin is a site-directed mutant of VU-1 calmodulin that is identical in sequence except for the substitution of an arginine at position 115 and thus is incapable of methylation. Both calmodulin genes, under the control of the cauliflower mosaic virus 35S promoter, were expressed in transgenic tobacco. Foreign calmodulin protein accumulated in plant tissues to levels equivalent to that of the endogenous calmodulin. All transformed lines of VU-1 plants were indistinguishable from untransformed controls with respect to growth and development. However, all transformed lines of VU-3 plants were characterized by decreased stem internode growth, reduced seed production, and reduced seed and pollen viability. The data suggest that these phenotypes are the result of the expression of the calmodulin mutant rather than the position of transferred DNA insertion or the overall alteration of calmodulin levels. Analyses of the activity of the purified transgenic calmodulins suggest that calmodulin-dependent NAD kinase is among the potential targets that may have altered regulation in VU-3 transgenic plants. Images PMID:1325656

  8. Major muscle systems in the larval caenogastropod, Ilyanassa obsoleta, display different patterns of development.

    PubMed

    Evans, Carol C E; Dickinson, Amanda J G; Croll, Roger P

    2009-10-01

    This study describes the anatomical and developmental aspects of muscular development from the early embryo to competent larval stage in the gastropod Ilyanassa obsoleta. Staining of F-actin revealed differential spatial and temporal patterns of several muscles. In particular, two major muscles, the larval retractor and pedal retractor muscles originate independently and display distinct developmental patterns similar to observations in other gastropod species. Additionally, together with the larval retractor muscle, the accessory larval muscle developed in the embryo at the trochophore stage. Therefore, both these muscles develop prior to ontogenetic torsion. The pedal retractor muscle marked the most abundant growth in the mid veliger stage. Also during the middle stage, the metapodial retractor muscle and opercular retractor muscle grew concurrently with development of the foot. We show evidence that juvenile muscles, such as the buccal mass muscle and siphon muscle develop initially during the late veliger stage. Collectively, these findings substantiate that larval myogenesis involves a complex sequence of events that appear evolutionary conserved within the gastropods, and set the stage for future studies using this model species to address issues concerning the evolution and eventual fates of larval musculature in molluscs.

  9. The role of internal waves in larval fish interactions with potential predators and prey

    NASA Astrophysics Data System (ADS)

    Greer, Adam T.; Cowen, Robert K.; Guigand, Cedric M.; Hare, Jonathan A.; Tang, Dorothy

    2014-09-01

    Tidally driven internal wave packets in coastal environments have the potential to influence patchiness of larval fishes, prey, and gelatinous predators. We used the In Situ Ichthyoplankton Imaging System (ISIIS) to synoptically sample larval fishes, copepods, and planktonic predators (ctenophores, hydromedusae, chaetognaths, and polychaetes) across these predictable features in the summer near Stellwagen Bank, Massachusetts, USA. Full water column profiles and fixed depth transects (∼10 m depth) were used to quantify vertical and horizontal components of the fish and invertebrate distributions during stable and vertically mixed conditions associated with tidally generated internal waves. Larval fishes, consisting mostly of Urophycis spp., Merluccius bilinearis, and Labridae, were concentrated near the surface, with larger sizes generally occupying greater depths. During stable water column conditions, copepods formed a near surface thin layer several meters above the chlorophyll-a maximum that was absent when internal waves were propagating. In contrast, ctenophores and other predators were much more abundant at depth, but concentrations near 10 m increased immediately after the internal hydraulic jump mixed the water column. During the propagation of internal waves, the fine-scale abundance of larval fishes was more correlated with the abundance of gelatinous predators and less correlated with copepods compared to the stable conditions. Vertical oscillations caused by the internal hydraulic jump can disperse patches of zooplankton and force surface dwelling larval fishes into deeper water where probability of predator contact is increased, creating conditions potentially less favorable for larval fish growth and survival on short time scales.

  10. CO2 and fertility affect growth and reproduction but not susceptibility to aphids in field grown Solanum ptycanthum

    SciTech Connect

    Long, T.M.

    1995-09-01

    In general, C3 annual plants respond positively in terms of growth, reproduction and biomass accrued when grown under elevated levels of atmospheric carbon dioxide. However, most studies documenting this response have been conducted in growth chambers where plants can be reared under conditions free form environmental stressors such as nutrient and water constraints, UV exposure and damage from pests. During the 1993 fieldseason, I grew 200 individuals of Solanum ptycanthum in an array of 10 outdoor, open-topped CO2 enclosures (5 @ 700 ppm CO2) at the University of Michigan Biological Station in Pellston, MI. Half of the plants were grown in a 50;50 mix of native C-horizon soil and topsoil (low fertility); the other half were grown in 100% topsoil (high-fertility). Plants were censused throughout the growing season for flower and fruit production, growth rate and degree of infestation of aphids. Fertility and CO2 both significantly affected production of flowers and fruits, but only fertility was significantly related to vegetative growth. Aphid infestation varied significantly among enclosures, but was not related to CO2 or fertility.

  11. Using post-settlement demography to estimate larval survivorship: a coral reef fish example.

    PubMed

    Johnson, D W; Christie, M R; Stallings, C D; Pusack, T J; Hixon, M A

    2015-11-01

    Many species have multi-stage life cycles in which the youngest stages (e.g., larvae) are small, dispersive, and abundant, whereas later stages are sessile or sedentary. Quantifying survival throughout such early stages is critical for understanding dispersal, population dynamics, and life history evolution. However, dispersive stages can be very difficult to sample in situ, and estimates of survival through the entire duration of these stages are typically poor. Here we describe how demographic information from juveniles and adults can be used to estimate survival throughout a dispersive larval stage that was not sampled directly. Using field measurements of demography, we show that detailed information on post-settlement growth, survival, and reproduction can be used to estimate average larval survivorship under the assumption that a typical individual replaces itself over its lifetime. Applying this approach to a common coral reef fish (bicolor damselfish, Stegastes partitus), we estimated average larval survivorship to be 0.108% (95% CI 0.025-0.484). We next compared this demography-based estimate to an expected value derived from published estimates of larval mortality rates. Our estimate of larval survivorship for bicolor damselfish was approximately two orders of magnitude greater than what would be expected if larval mortality of this species followed the average, size-dependent pattern of mortality inferred from a published sample of marine fishes. Our results highlight the importance of understanding mortality during the earliest phases of larval life, which are typically not sampled, as well as the need to understand the details of how larval mortality scales with body size.

  12. Mouse ovarian follicles secrete factors affecting the growth and development of like-sized ovarian follicles in vitro.

    PubMed

    Spears, Norah; Baker, Stuart; Srsen, Vlastimil; Lapping, Rebecca; Mullan, Julie; Nelson, Robert; Allison, Vivian

    2002-12-01

    A series of experiments have been carried out to determine whether follicles secrete factors able to affect the growth and development of other, like-sized follicles. Late preantral mouse ovarian follicles were either cocultured or cultured in media conditioned by previously cultured follicles. In particular, the experiments examined whether follicles do secrete such factors, whether the level of FSH in the culture media can affect that process, and what the nature of such secretory factor(s) might be. First, pairs of follicles were cocultured across a polycarbonate membrane containing pores. This showed that communication between the follicles resulted in the stimulation of growth and that the stimulation was due, at least in part, to the production of secretory factor(s). In subsequent experiments, follicles were cultured in media that had been preconditioned by previously cultured follicles. The concentration of FSH in the cultures determined the effect of the conditioned media: conditioned media was stimulatory to follicle growth when levels of FSH remained high throughout the culture, but inhibitory when FSH levels were dropped midway through the cultures. Heat inactivation removed this inhibitory effect, showing that the factor was likely to be a protein; addition of follistatin to the conditioned media did not alter its effect, indicating that the factor was unlikely to be activin. We have shown through a series of culture experiments that mouse follicles secrete factor(s) that can affect the development of other like-sized follicles when cultured from the late preantral to Graafian stages. Furthermore, we have shown that the effect (or production) of such factors is dependent on the FSH environment of the follicles.

  13. Drainage affects tree growth and C and N dynamics in a minerotrophic peatland.

    PubMed

    Choi, Woo-Jung; Chang, Scott X; Bhatti, Jagtar S

    2007-02-01

    The lowering of the water table resulting from peatland drainage may dramatically alter C and N cycling in peatland ecosystems, which contain one-third of the total terrestrial C. In this study, tree annual ring width and C (delta(13)C) and N (delta(15)N) isotope ratios in soil and plant tissues (tree foliage, growth rings, and understory foliage) in a black spruce-tamarack (Picea mariana-Larix laricina) mixed-wood forest were examined to study the effects of drainage on tree growth and C and N dynamics in a minerotrophic peatland in west-central Alberta, Canada. Drainage increased the delta(15)N of soil NH4+ from a range of +0.6% per hundred to +2.9% per hundred to a range of +4.6% per hundred to +7.0% per hundred most likely through increased nitrification following enhanced mineralization. Plant uptake of 15N-enriched NH4+ in the drained treatment resulted in higher plant delta15N (+0.8% per hundred to +1.8% per hundred in the drained plots and -3.9% per hundred to -5.4% per hundred in the undrained plots), and deposition of litterfall N enriched with 15N increased the delta15N of total soil N in the surface layer in the drained (+2.9% per hundred) as compared with that in the undrained plots (+0.6% per hundred). The effect of drainage on foliar delta(13)C was species-specific, i.e., only tamarack showed a considerably less negative foliar delta(13)C in the drained (-28.1% per hundred) than in the undrained plots (-29.1% per hundred), indicating improved water use efficiency (WUE) by drainage. Tree ring area increments were significantly increased following drainage, and delta(13)C and delta(15)N in tree growth rings of both species showed responses to drainage retrospectively. Tree-ring delta(13)C data suggested that drainage improved WUE of both species, with a greater and more prolonged response in tamarack than in black spruce. Our results indicate that drainage caused the studied minerotrophic peatland to become a more open ecosystem in terms of C and N

  14. Titanium dioxide nanoparticles affect the growth and microRNA expression of tobacco (Nicotiana tabacum).

    PubMed

    Frazier, Taylor P; Burklew, Caitlin E; Zhang, Baohong

    2014-03-01

    Titanium dioxide (TiO(2)) is one of the most widely used pigments in the world. Due to its heavy use in industry and daily life, such as food additives, cosmetics, pharmaceuticals, and paints, many residues are released into the environment and currently TiO(2) nanoparticles are considered an emerging environmental contaminant. Although several studies have shown the effect of TiO(2) nanoparticles on a wide range of organisms including bacteria, algae, plankton, fish, mice, and rats, little research has been performed on land plants. In this study, we investigated the effect of TiO(2) nanoparticles on the growth, development, and gene expression of tobacco, an important economic and agricultural crop in the southeastern USA as well as around the world. We found that TiO(2) nanoparticles significantly inhibited the germination rates, root lengths, and biomasses of tobacco seedlings after 3 weeks of exposure to 0.1, 1, 2.5, and 5 % TiO(2) nanoparticles and that overall growth and development of the tobacco seedlings significantly decreased as TiO(2) nanoparticle concentrations increased. Overall, tobacco roots were the most sensitive to TiO(2) nanoparticle exposure. Nano-TiO(2) also significantly influenced the expression profiles of microRNAs (miRNAs), a recently discovered class of small endogenous noncoding RNAs (∼20-22 nt) that are considered important gene regulators and have been shown to play an important role in plant development as well as plant tolerance to abiotic stresses such as drought, salinity, cold, and heavy metal. Low concentrations (0.1 and 1 %) of TiO(2) nanoparticles dramatically induced miRNA expression in tobacco seedlings with miR395 and miR399 exhibiting the greatest fold changes of 285-fold and 143-fold, respectively. The results of this study show that TiO(2) nanoparticles have a negative impact on tobacco growth and development and that miRNAs may play an important role in tobacco response to heavy metals/nanoparticles by regulating

  15. Simulated microgravity affects growth of Escherichia coli and recombinant beta-D-glucuronidase production.

    PubMed

    Xiang, Liang; Qi, Feng; Dai, DaZhang; Li, Chun; Jiang, YuanDa

    2010-10-01

    Effects of simulated microgravity (SMG) on bacteria have been studied in various aspects. However, few reports are available about production of recombinant protein expressed by bacteria in SMG. In this study growth of E. coli BL21 (DE3) cells transformed with pET-28a (+)-pgus in double-axis clinostat that could model low shear SMG environment and the recombinant beta-D-glucuronidase (PGUS) expression have been investigated. Results showed that the cell dry weights in SMG were 16.47%, 38.06%, and 28.79% more than normal gravity (NG) control, and the efficiency of the recombinant PGUS expression in SMG were 18.33%, 19.36%, and 33.42% higher than that in NG at 19 degrees C, 28 degrees C, and 37 degrees C, respectively (P < 0.05).

  16. Andrographolide inhibits hepatoma cells growth and affects the expression of cell cycle related proteins.

    PubMed

    Shen, Kai-Kai; Liu, Tian-Yu; Xu, Chong; Ji, Li-Li; Wang, Zheng-Tao

    2009-09-01

    The present study is aimed to investigate the toxic effects of andrographolide (Andro) on hepatoma cells and elucidate its preliminary mechanisms. After cells were treated with different concentrations of Andro (0-50 micromol x L(-1)) for 24 h, cell viability was evaluated with 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, after hepatoma cells (Hep3B and HepG2) were treated with different concentrations of Andro (0-30 micromol x L(-1)) for 14 d, the number of colony formation was accounted under microscope. Cell cycle related proteins such as Cdc-2, phosphorylated-Cdc-2, Cyclin B and Cyclin D1 were detected with Western blotting assay and the cell cycle was analyzed by flow cytometry using propidium iodide staining. MTT results showed that Andro induced growth inhibition of hepatoma cells in a concentration-dependent manner but had no significant effects on human normal liver L-02 cells. Andro dramatically decreased the colony formation of hepatoma cells in the concentration-dependent manner. Moreover, Andro induced a decrease of Hep3B cells at the G0-G1 phase and a concomitant accumulation of cells at G2-M phase. At the molecular level, Western blotting results showed that Andro decreased the expression of Cdc-2, phosphorylated-Cdc-2, Cyclin D1 and Cyclin B proteins in a time-dependent manner, which are all cell cycle related proteins. Taken together, the results demonstrated that Andro specifically inhibited the growth of hepatoma cells and cellular cell cycle related proteins were possibly involved in this process.

  17. Growth condition-dependent Esp expression by Enterococcus faecium affects initial adherence and biofilm formation.

    PubMed

    Van Wamel, Willem J B; Hendrickx, Antoni P A; Bonten, Marc J M; Top, Janetta; Posthuma, George; Willems, Rob J L

    2007-02-01

    A genetic subpopulation of Enterococcus faecium, called clonal complex 17 (CC-17), is strongly associated with hospital outbreaks and invasive infections. Most CC-17 strains contain a putative pathogenicity island encoding the E. faecium variant of enterococcal surface protein (Esp). Western blotting, flow cytometric analyses, and electron microscopy showed that Esp is expressed and exposed on the surface of E. faecium, though Esp expression and surface exposure are highly varied among different strains. Furthermore, Esp expression depends on growth conditions like temperature and anaerobioses. When grown at 37 degrees C, five of six esp-positive E. faecium strains showed significantly increased levels of surface-exposed Esp compared to bacteria grown at 21 degrees C, which was confirmed at the transcriptional level by real-time PCR. In addition, a significant increase in surface-exposed Esp was found in half of these strains when grown at 37 degrees C under anaerobic conditions compared to the level in bacteria grown under aerobic conditions. Finally, amounts of surface-exposed Esp correlated with initial adherence to polystyrene (R(2) = 0.7146) and biofilm formation (R(2) = 0.7535). Polystyrene adherence was competitively inhibited by soluble recombinant N-terminal Esp. This study demonstrates that Esp expression on the surface of E. faecium (i) varies consistently between strains, (ii) is growth condition dependent, and (iii) is quantitatively correlated with initial adherence and biofilm formation. These data indicate that E. faecium senses and responds to changing environmental conditions, which might play a role in the early stages of infection when bacteria transit from oxygen-rich conditions at room temperature to anaerobic conditions at body temperature. In addition, variation of surface exposure may explain the contrasting findings reported on the role of Esp in biofilm formation.

  18. Terpenoids inhibit Candida albicans growth by affecting membrane integrity and arrest of cell cycle.

    PubMed

    Zore, Gajanan B; Thakre, Archana D; Jadhav, Sitaram; Karuppayil, S Mohan

    2011-10-15

    Anti-Candida potential of six terpenoids were evaluated in this study against various isolates of Candida albicans (n=39) and non-C. albicans (n=9) that are differentially susceptible to fluconazole. All the six terpenoids tested, showed excellent activity and were equally effective against isolates of Candida sps., tested in this study. Linalool and citral were the most effective ones, inhibiting all the isolates at ≤0.064% (v/v). Five among the six terpenoids tested were fungicidal. Time dependent kill curve assay showed that MFCs of linalool and eugenol were highly toxic to C. albicans, killing 99.9% inoculum within seven min of exposure, while that of citronellal, linalyl acetate and citral required 15min, 1h and 2h, respectively. FIC index values (Linalool - 0.140, benzyl benzoate - 0.156, eugenol - 0.265, citral - 0.281 and 0.312 for linalyl acetate and citronellal) and isobologram obtained by checker board assay showed that all the six terpenoids tested exhibit excellent synergistic activity with fluconazole against a fluconazole resistant strain of C. albicans. Terpenoids tested arrested C. albicans cells at different phases of the cell cycle i.e. linalool and LA at G1, citral and citronellal at S phase and benzyl benzoate at G2-M phase and induced apoptosis. Linalool, citral, citronellal and benzyl benzoate caused more than 50% inhibition of germ tube induction at 0.008%, while eugenol and LA required 0.032 and 0.016% (v/v) concentrations, respectively. MICs of all the terpenoids for the C. albicans growth were non toxic to HeLa cells. Terpenoids tested exhibited excellent activity against C. albicans yeast and hyphal form growth at the concentrations that are non toxic to HeLa cells. Terpenoids tested in this study may find use in antifungal chemotherapy, not only as antifungal agents but also as synergistic agents along with conventional drugs like fluconazole.

  19. Antagonizing the Hedgehog Pathway with Vismodegib Impairs Malignant Pleural Mesothelioma Growth In Vivo by Affecting Stroma.

    PubMed

    Meerang, Mayura; Bérard, Karima; Felley-Bosco, Emanuela; Lauk, Olivia; Vrugt, Bart; Boss, Andreas; Kenkel, David; Broggini-Tenzer, Angela; Stahel, Rolf A; Arni, Stephan; Weder, Walter; Opitz, Isabelle

    2016-05-01

    An autocrine-driven upregulation of the Hedgehog (Hh) signaling pathway has been described in malignant pleural mesothelioma (MPM), in which the ligand, desert Hh (DHH), was produced from tumor cells. However, our investigation revealed that the Hh pathway is activated in both tumor and stroma of MPM tumor specimens and an orthotopic immunocompetent rat MPM model. This was demonstrated by positive immunohistochemical staining of Glioma-associated oncogene 1 (GLI1) and Patched1 (PTCH1) in both tumor and stromal fractions. DHH was predominantly expressed in the tumor fractions. To further investigate the role of the Hh pathway in MPM stroma, we antagonized Hh signaling in the rat model of MPM using a Hh antagonist, vismodegib, (100 mg/kg orally). Daily treatment with vismodegib efficiently downregulated Hh target genes Gli1, Hedgehog Interacting Protein (Hhip), and Ptch1, and caused a significant reduction of tumor volume and tumor growth delay. Immunohistochemical analyses revealed that vismodegib treatment primarily downregulated GLI1 and HHIP in the stromal compartment along with a reduced expression of previously described fibroblast Hh-responsive genes such as Fibronectin (Fn1) and Vegfa Primary cells isolated from the rat model cultured in 3% O2 continued to express Dhh but did not respond to vismodegib in vitro However, culture supernatant from these cells stimulated Gli1, Ptch1, and Fn1 expression in mouse embryonic fibroblasts, which was suppressed by vismodegib. Our study provides new evidence regarding the role of Hh signaling in MPM stroma in the maintenance of tumor growth, emphasizing Hh signaling as a treatment target for MPM. Mol Cancer Ther; 15(5); 1095-105. ©2016 AACR.

  20. COX-2 inhibition affects growth rate of Chlamydia muridarum within epithelial cells.

    PubMed

    Liu, Wei; Dubinett, Steven; Patterson, Simie Lavern A; Kelly, Kathleen A

    2006-02-01

    Chlamydiae alter apoptosis of host target cells, which regulates their growth. Cyclooxygenase-2 (COX-2), the rate-limiting enzyme for prostaglandin E2 (PGE2) production, modulates epithelial cell survival. We addressed whether endogenous PGE2 alters chlamydial growth or apoptosis of epithelial cells infected with Chlamydia muridarum. PGE2 is secreted by infected host cells in the genital tract (GT). Using immunohistochemical techniques, we found that COX-2 enzyme was localized to epithelial cells in the GT in vivo. Pellets of the COX-2 enzyme inhibitor, NS-398, and placebo were implanted in mice subcutaneously and released a constant amount of these chemicals throughout the infection. NS-398-treated mice were found to exhibit 10-fold lower bacterial load than the placebo group on day 3 post infection, suggesting disruption of the chlamydial developmental cycle. To prove this, the human lung adenocarcinoma cell line A549 was then infected with different MOIs of C. muridarum in the presence of multiple concentrations of NS-398 in vitro. There was no difference in inclusion forming units (IFUs) between NS-389-treated and untreated cells. We also found no alterations in C. muridarum IFUs in A549 cells transfected with a 2.0 kb cDNA fragment of human COX-2 cloned in the sense (S) or anti-sense (AS) orientation. However, the inclusion size was reduced and the number of EB was significantly diminished during reinfection in AS-transfected cells. In addition, the absence of COX-2 did not significantly modify apoptosis in infected cells. In total, COX-2 deficiency reduces the infectious burden in vivo and may modulate transmission of the organism.

  1. Affective determinants of anxiety and depression development in children and adolescents: an individual growth curve analysis.

    PubMed

    De Bolle, Marleen; De Clercq, Barbara; Decuyper, Mieke; De Fruyt, Filip

    2011-12-01

    The tripartite model (in Clark and Watson, J Abnorm Psychol 100:316-336, 1991) comprises Negative Affect (NA), Positive Affect (PA), and Physiological Hyperarousal (PH), three temperamental-based dimensions. The current study examined the tripartite model's assumptions that (a) NA interacts with PA to predict subsequent depressive (but not anxiety) symptom developments and (b) NA interacts with PH to predict subsequent anxiety (but not depressive) symptom developments in a sample of 243 community and referred children and adolescents (42.8% boys; M age = 10.87 years, SD = 1.83). Results confirmed that individuals with a combined high NA/low PA profile display the least favorable course of depressive -but not anxiety- symptoms. In contrast with the model, the combination of NA and PH influenced the development of depression, but not anxiety. Relations were not moderated by sex or sample. Results revealed that the assessment of the tripartite components is warranted as it can help to identify children at risk for an unfavorable depressive symptom course.

  2. Mutation of the central nervous system neuroblast proliferation repressor ana leads to defects in larval olfactory behavior.

    PubMed

    Park, Y; Caldwell, M C; Datta, S

    1997-08-01

    In the developing nervous system, interactions between glia and immature neurons or neuroblasts regulate axon pathfinding, migration, and cell division, and therefore affect structure and function. Glial control of neuroblast cell division has been documented by studies of the anachronism (ana) gene of Drosophila melanogaster. ana encodes a glycoprotein which, in the developing larval central nervous system, is secreted by glia that neighbor regulated neuroblasts. Mutations in ana lead to premature neuroblast proliferation in the larval brain. Examination of lacZ expression from an ana enhancer trap line as well as detection of the ana protein show that ana is also expressed in the larval antennal-maxillary complex (AMC) at all larval stages. As previously reported for the central nervous system, ana expression in the AMC appears to be co