WorldWideScience

Sample records for larval developmental pathway

  1. Larval developmental rate, metabolic rate and future growth performance in Atlantic salmon

    DEFF Research Database (Denmark)

    Serrano, Jonathan Vaz; Åberg, Madelene; Gjoen, Hans Magnus

    2009-01-01

    , quantified as time to first feeding, and growth in later stages was demonstrated in Atlantic salmon (Salmo salar L.). The observed relationship between future growth and larval developmental rate suggests that sorting larvae by time to first feeding can be a potential tool to optimize feeding strategies...... and growth in commercial rearing of Atlantic salmon. Furthermore, the link between larval standard metabolic rate and developmental rate and future growth is discussed in the present study....

  2. Developmental Programming, a Pathway to Disease

    Science.gov (United States)

    Cardoso, Rodolfo C.; Puttabyatappa, Muraly

    2016-01-01

    Accumulating evidence suggests that insults occurring during the perinatal period alter the developmental trajectory of the fetus/offspring leading to long-term detrimental outcomes that often culminate in adult pathologies. These perinatal insults include maternal/fetal disease states, nutritional deficits/excess, stress, lifestyle choices, exposure to environmental chemicals, and medical interventions. In addition to reviewing the various insults that contribute to developmental programming and the benefits of animal models in addressing underlying mechanisms, this review focuses on the commonalities in disease outcomes stemming from various insults, the convergence of mechanistic pathways via which various insults can lead to common outcomes, and identifies the knowledge gaps in the field and future directions. PMID:26859334

  3. Short-term developmental effects and potential mechanisms of azoxystrobin in larval and adult zebrafish (Danio rerio).

    Science.gov (United States)

    Cao, Fangjie; Wu, Peizhuo; Huang, Lan; Li, Hui; Qian, Le; Pang, Sen; Qiu, Lihong

    2018-05-01

    Previous study indicated that azoxystrobin had high acute toxicity to zebrafish, and larval zebrafish were more sensitive to azoxystrobin than adult zebrafish. The objective of the present study was to investigate short-term developmental effects and potential mechanisms of azoxystrobin in larval and adult zebrafish. After zebrafish embryos and adults were exposed to 0.01, 0.05 and 0.20 mg/L azoxystrobin (equal to 25, 124 and 496 nM azoxystrobin, respectively) for 8 days, the lethal effect, physiological responses, liver histology, mitochondrial ultrastructure, and expression alteration of genes related to mitochondrial respiration, oxidative stress, cell apoptosis and innate immune response were determined. The results showed that there was no significant effect on larval and adult zebrafish after exposure to 0.01 mg/L azoxystrobin. However, increased ROS, MDA concentration and il1b in larval zebrafish, as well as increased il1b, il8 and cxcl-c1c in adult zebrafish were induced after exposure to 0.05 mg/L azoxystrobin. Reduced mitochondrial complex III activity and ATP concentration, increased SOD activity, ROS and MDA concentration, decreased cytb, as well as increased sod1, sod2, cat, il1b, il8 and cxcl-c1c were observed both in larval and adult zebrafish after exposure to 0.20 mg/L azoxystrobin; meanwhile, increased p53, bax, apaf1 and casp9, alteration of liver histology and mitochondrial ultrastructure in larval zebrafish, and alteration of mitochondrial ultrastructure in adult zebrafish were also induced. The results demonstrated that azoxytrobin induced short-term developmental effects on larval zebrafish and adult zebrafish, including mitochondrial dysfunction, oxidative stress, cell apoptosis and innate immune response. Statistical analysis indicated that azoxystrobin induced more negative effects on larval zebrafish, which might be the reason for the differences of developmental toxicity between larval and adult zebrafish caused by

  4. Larval Red Drum (Sciaenops ocellatus) Sublethal Exposure to Weathered Deepwater Horizon Crude Oil: Developmental and Transcriptomic Consequences.

    Science.gov (United States)

    Xu, Elvis Genbo; Khursigara, Alex J; Magnuson, Jason; Hazard, E Starr; Hardiman, Gary; Esbaugh, Andrew J; Roberts, Aaron P; Schlenk, Daniel

    2017-09-05

    The Deepwater Horizon (DWH) incident resulted in extensive oiling of the pelagic zone and shoreline habitats of many commercially important fish species. Exposure to the water-accommodated fraction (WAF) of oil from the spill causes developmental toxicity through cardiac defects in pelagic fish species. However, few studies have evaluated the effects of the oil on near-shore estuarine fish species such as red drum (Sciaenops ocellatus). Following exposure to a certified weathered slick oil (4.74 μg/L ∑PAH 50 ) from the DWH event, significant sublethal impacts were observed ranging from impaired nervous system development [average 17 and 22% reductions in brain and eye area at 48 h postfertilization (hpf), respectively] to abnormal cardiac morphology (100% incidence at 24, 48, and 72 hpf) in red drum larvae. Consistent with the phenotypic responses, significantly differentially expressed transcripts, enriched gene ontology, and altered functions and canonical pathways predicted adverse outcomes in nervous and cardiovascular systems, with more pronounced changes at later larval stages. Our study demonstrated that the WAF of weathered slick oil of DWH caused morphological abnormalities predicted by a suite of advanced bioinformatic tools in early developing red drum and also provided the basis for a better understanding of molecular mechanisms of crude oil toxicity in fish.

  5. Developmental Pathways in Juvenile Externalizing and Internalizing Problems

    Science.gov (United States)

    Loeber, Rolf; Burke, Jeffrey D.

    2011-01-01

    This article summarizes the empirical studies showing pathways in the development of externalizing and delinquent behaviors. Pathways are defined as the orderly temporal development between more than two problem behaviors. The paper addresses the following questions: (1) What are the developmental pathways between different diagnoses of Disruptive…

  6. Developmental Pathways Are Blueprints for Designing Successful Crops

    Directory of Open Access Journals (Sweden)

    Ben Trevaskis

    2018-06-01

    Full Text Available Genes controlling plant development have been studied in multiple plant systems. This has provided deep insights into conserved genetic pathways controlling core developmental processes including meristem identity, phase transitions, determinacy, stem elongation, and branching. These pathways control plant growth patterns and are fundamentally important to crop biology and agriculture. This review describes the conserved pathways that control plant development, using Arabidopsis as a model. Historical examples of how plant development has been altered through selection to improve crop performance are then presented. These examples, drawn from diverse crops, show how the genetic pathways controlling development have been modified to increase yield or tailor growth patterns to suit local growing environments or specialized crop management practices. Strategies to apply current progress in genomics and developmental biology to future crop improvement are then discussed within the broader context of emerging trends in plant breeding. The ways that knowledge of developmental processes and understanding of gene function can contribute to crop improvement, beyond what can be achieved by selection alone, are emphasized. These include using genome re-sequencing, mutagenesis, and gene editing to identify or generate novel variation in developmental genes. The expanding scope for comparative genomics, the possibility to engineer new developmental traits and new approaches to resolve gene–gene or gene–environment interactions are also discussed. Finally, opportunities to integrate fundamental research and crop breeding are highlighted.

  7. White matter pathways in persistent developmental stuttering: Lessons from tractography.

    Science.gov (United States)

    Kronfeld-Duenias, Vered; Civier, Oren; Amir, Ofer; Ezrati-Vinacour, Ruth; Ben-Shachar, Michal

    2018-03-01

    Fluent speech production relies on the coordinated processing of multiple brain regions. This highlights the role of neural pathways that connect distinct brain regions in producing fluent speech. Here, we aim to investigate the role of the white matter pathways in persistent developmental stuttering (PDS), where speech fluency is disrupted. We use diffusion weighted imaging and tractography to compare the white matter properties between adults who do and do not stutter. We compare the diffusion properties along 18 major cerebral white matter pathways. We complement the analysis with an overview of the methodology and a roadmap of the pathways implicated in PDS according to the existing literature. We report differences in the microstructural properties of the anterior callosum, the right inferior longitudinal fasciculus and the right cingulum in people who stutter compared with fluent controls. Persistent developmental stuttering is consistently associated with differences in bilateral distributed networks. We review evidence showing that PDS involves differences in bilateral dorsal fronto-temporal and fronto-parietal pathways, in callosal pathways, in several motor pathways and in basal ganglia connections. This entails an important role for long range white matter pathways in this disorder. Using a wide-lens analysis, we demonstrate differences in additional, right hemispheric pathways, which go beyond the replicable findings in the literature. This suggests that the affected circuits may extend beyond the known language and motor pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. A developmental and energetic basis linking larval oyster shell formation to acidification sensitivity

    Science.gov (United States)

    Waldbusser, George G.; Brunner, Elizabeth L.; Haley, Brian A.; Hales, Burke; Langdon, Christopher J.; Prahl, Frederick G.

    2013-05-01

    Acidified waters are impacting commercial oyster production in the U.S. Pacific Northwest, and favorable carbonate chemistry conditions are predicted to become less frequent. Within 48 h of fertilization, unshelled Pacific oyster (Crassostrea gigas) larvae precipitate roughly 90% of their body weight as calcium carbonate. We measured stable carbon isotopes in larval shell and tissue and in algal food and seawater dissolved inorganic carbon in a longitudinal study of larval development and growth. Using these data and measured biochemical composition of larvae, we show that sensitivity of initial shell formation to ocean acidification results from diminished ability to isolate calcifying fluid from surrounding seawater, a limited energy budget and a strong kinetic demand for calcium carbonate precipitation. Our results highlight an important link between organism physiology and mineral kinetics in larval bivalves and suggest the consideration of mineral kinetics may improve understanding winners and losers in a high CO2 world.

  9. Tyrosine pathway regulation is host-mediated in the pea aphid symbiosis during late embryonic and early larval development.

    Science.gov (United States)

    Rabatel, Andréane; Febvay, Gérard; Gaget, Karen; Duport, Gabrielle; Baa-Puyoulet, Patrice; Sapountzis, Panagiotis; Bendridi, Nadia; Rey, Marjolaine; Rahbé, Yvan; Charles, Hubert; Calevro, Federica; Colella, Stefano

    2013-04-10

    Nutritional symbioses play a central role in insects' adaptation to specialized diets and in their evolutionary success. The obligatory symbiosis between the pea aphid, Acyrthosiphon pisum, and the bacterium, Buchnera aphidicola, is no exception as it enables this important agricultural pest insect to develop on a diet exclusively based on plant phloem sap. The symbiotic bacteria provide the host with essential amino acids lacking in its diet but necessary for the rapid embryonic growth seen in the parthenogenetic viviparous reproduction of aphids. The aphid furnishes, in exchange, non-essential amino acids and other important metabolites. Understanding the regulations acting on this integrated metabolic system during the development of this insect is essential in elucidating aphid biology. We used a microarray-based approach to analyse gene expression in the late embryonic and the early larval stages of the pea aphid, characterizing, for the first time, the transcriptional profiles in these developmental phases. Our analyses allowed us to identify key genes in the phenylalanine, tyrosine and dopamine pathways and we identified ACYPI004243, one of the four genes encoding for the aspartate transaminase (E.C. 2.6.1.1), as specifically regulated during development. Indeed, the tyrosine biosynthetic pathway is crucial for the symbiotic metabolism as it is shared between the two partners, all the precursors being produced by B. aphidicola. Our microarray data are supported by HPLC amino acid analyses demonstrating an accumulation of tyrosine at the same developmental stages, with an up-regulation of the tyrosine biosynthetic genes. Tyrosine is also essential for the synthesis of cuticular proteins and it is an important precursor for cuticle maturation: together with the up-regulation of tyrosine biosynthesis, we observed an up-regulation of cuticular genes expression. We were also able to identify some amino acid transporter genes which are essential for the switch

  10. Masking of a circadian behavior in larval zebrafish involves the thalamo-habenula pathway.

    Science.gov (United States)

    Lin, Qian; Jesuthasan, Suresh

    2017-06-22

    Changes in illumination can rapidly influence behavior that is normally controlled by the circadian clock. This effect is termed masking. In mice, masking requires melanopsin-expressing retinal ganglion cells that detect blue light and project to the thalamus. It is not known whether masking is wavelength-dependent in other vertebrates, nor is it known whether the thalamus is also involved or how it influences masking. Here, we address these questions in zebrafish. We find that diel vertical migration, a circadian behavior in larval zebrafish, is effectively triggered by blue, but not by red light. Two-photon calcium imaging reveals that a thalamic nucleus and a downstream structure, the habenula, have a sustained response to blue but not to red light. Lesioning the habenula reduces light-evoked climbing. These data suggest that the thalamo-habenula pathway is involved in the ability of blue light to influence a circadian behavior.

  11. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    International Nuclear Information System (INIS)

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc

    2014-01-01

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors

  12. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc, E-mail: m.muller@ulg.ac.be

    2014-01-15

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors.

  13. TRWG developmental pathway for biospecimen-based assessment modalities

    Energy Technology Data Exchange (ETDEWEB)

    Translational Research Working Group; Srivastava, Sudhir; Gray, Joe W.; Reid, Brian J.; Grad, Oren; Greenwood, Addison; Hawk, Ernest T.

    2008-09-03

    The Translational Research Working Group (TRWG) was created as a national initiative to evaluate the current status of NCI's investment in translational research and envision its future. The TRWG conceptualized translational research as a set of six developmental processes or pathways focused on various clinical goals. One of those pathways describes the development of biospecimen-based assays that utilize biomarkers for the detection, diagnosis, prognosis, and assessment of response to cancer treatment. The biospecimen-based assessment modality (BM) pathway was conceived not as comprehensive description of the corresponding real-world processes, but rather as a tool designed to facilitate movement of a candidate assay through the translational process to the point where it can be handed off for definitive clinical testing. This paper introduces the pathway in the context of prior work and discusses key challenges associated with the biomarker development process in light of the pathway.

  14. Psychological autonomy and hierarchical relatedness as organizers of developmental pathways

    OpenAIRE

    Keller, Heidi

    2016-01-01

    The definition of self and others can be regarded as embodying the two dimensions of autonomy and relatedness. Autonomy and relatedness are two basic human needs and cultural constructs at the same time. This implies that they may be differently defined yet remain equally important. The respective understanding of autonomy and relatedness is socialized during the everyday experiences of daily life routines from birth on. In this paper, two developmental pathways are portrayed that emphasize d...

  15. The Drosophila Perlecan gene trol regulates multiple signaling pathways in different developmental contexts

    Directory of Open Access Journals (Sweden)

    Perry Trinity L

    2007-11-01

    Full Text Available Abstract Background Heparan sulfate proteoglycans modulate signaling by a variety of growth factors. The mammalian proteoglycan Perlecan binds and regulates signaling by Sonic Hedgehog, Fibroblast Growth Factors (FGFs, Vascular Endothelial Growth Factor (VEGF and Platelet Derived Growth Factor (PDGF, among others, in contexts ranging from angiogenesis and cardiovascular development to cancer progression. The Drosophila Perlecan homolog trol has been shown to regulate the activity of Hedgehog and Branchless (an FGF homolog to control the onset of stem cell proliferation in the developing brain during first instar. Here we extend analysis of trol mutant phenotypes to show that trol is required for a variety of developmental events and modulates signaling by multiple growth factors in different situations. Results Different mutations in trol allow developmental progression to varying extents, suggesting that trol is involved in multiple cell-fate and patterning decisions. Analysis of the initiation of neuroblast proliferation at second instar demonstrated that trol regulates this event by modulating signaling by Hedgehog and Branchless, as it does during first instar. Trol protein is distributed over the surface of the larval brain, near the regulated neuroblasts that reside on the cortical surface. Mutations in trol also decrease the number of circulating plasmatocytes. This is likely to be due to decreased expression of pointed, the response gene for VEGF/PDGF signaling that is required for plasmatocyte proliferation. Trol is found on plasmatocytes, where it could regulate VEGF/PDGF signaling. Finally, we show that in second instar brains but not third instar brain lobes and eye discs, mutations in trol affect signaling by Decapentaplegic (a Transforming Growth Factor family member, Wingless (a Wnt growth factor and Hedgehog. Conclusion These studies extend the known functions of the Drosophila Perlecan homolog trol in both developmental and

  16. Developmental psychoneuroendocrine and psychoneuroimmune pathways from childhood adversity to disease.

    Science.gov (United States)

    Kuhlman, Kate Ryan; Chiang, Jessica J; Horn, Sarah; Bower, Julienne E

    2017-09-01

    Childhood adversity has been repeatedly and robustly linked to physical and mental illness across the lifespan. Yet, the biological pathways through which this occurs remain unclear. Functioning of the inflammatory arm of the immune system and the hypothalamic-pituitary-adrenal (HPA)-axis are both hypothesized pathways through which childhood adversity leads to disease. This review provides a novel developmental framework for examining the role of adversity type and timing in inflammatory and HPA-axis functioning. In particular, we identify elements of childhood adversity that are salient to the developing organism: physical threat, disrupted caregiving, and unpredictable environmental conditions. We propose that existing, well-characterized animal models may be useful in differentiating the effects of these adversity elements and review both the animal and human literature that supports these ideas. To support these hypotheses, we also provide a detailed description of the development and structure of both the HPA-axis and the inflammatory arm of the immune system, as well as recent methodological advances in their measurement. Recommendations for future basic, developmental, translational, and clinical research are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Disruption of the folate pathway in zebrafish causes developmental defects

    Directory of Open Access Journals (Sweden)

    Lee Marina S

    2012-04-01

    Full Text Available Abstract Background Folic acid supplementation reduces the risk of neural tube defects and congenital heart defects. The biological mechanisms through which folate prevents birth defects are not well understood. We explore the use of zebrafish as a model system to investigate the role of folate metabolism during development. Results We first identified zebrafish orthologs of 12 human folate metabolic genes. RT-PCR and in situ analysis indicated maternal transcripts supply the embryo with mRNA so that the embryo has an intact folate pathway. To perturb folate metabolism we exposed zebrafish embryos to methotrexate (MTX, a potent inhibitor of dihydrofolate reductase (Dhfr an essential enzyme in the folate metabolic pathway. Embryos exposed to high doses of MTX exhibited developmental arrest prior to early segmentation. Lower doses of MTX resulted in embryos with a shortened anterior-posterior axis and cardiac defects: linear heart tubes or incomplete cardiac looping. Inhibition of dhfr mRNA with antisense morpholino oligonucleotides resulted in embryonic lethality. One function of the folate pathway is to provide essential one-carbon units for dTMP synthesis, a rate-limiting step of DNA synthesis. After 24 hours of exposure to high levels of MTX, mutant embryos continue to incorporate the thymidine analog BrdU. However, additional experiments indicate that these embryos have fewer mitotic cells, as assayed with phospho-histone H3 antibodies, and that treated embryos have perturbed cell cycles. Conclusions Our studies demonstrate that human and zebrafish utilize similar one-carbon pathways. Our data indicate that folate metabolism is essential for early zebrafish development. Zebrafish studies of the folate pathway and its deficiencies could provide insight into the underlying etiology of human birth defects and the natural role of folate in development.

  18. Developmental Pathways to Preference and Popularity in Middle Childhood.

    Science.gov (United States)

    van den Berg, Yvonne H M; Deutz, Marike H F; Smeekens, Sanny; Cillessen, Antonius H N

    2017-09-01

    This study examined the associations between children's early life experiences with parents, ego resiliency and ego undercontrol, and peer group social status in a longitudinal, multimethod study from infancy to middle childhood. Participants were 129 children (52% boys) who were followed from 15 months of age to 9 years and their primary caregivers from the Nijmegen Longitudinal Study on Infant and Child Development. The measurements included observations of parent-child interaction, teacher ratings of ego resiliency and ego undercontrol, and peer-reported social status. Quality of parental interactive behavior was associated with ego resiliency and ego undercontrol. Ego resiliency and ego undercontrol were uniquely related to preference and popularity. The findings provide insight into the developmental pathways leading to the two distinct types of social status. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

  19. Psychological autonomy and hierarchical relatedness as organizers of developmental pathways.

    Science.gov (United States)

    Keller, Heidi

    2016-01-19

    The definition of self and others can be regarded as embodying the two dimensions of autonomy and relatedness. Autonomy and relatedness are two basic human needs and cultural constructs at the same time. This implies that they may be differently defined yet remain equally important. The respective understanding of autonomy and relatedness is socialized during the everyday experiences of daily life routines from birth on. In this paper, two developmental pathways are portrayed that emphasize different conceptions of autonomy and relatedness that are adaptive in two different environmental contexts with very different affordances and constraints. Western middle-class children are socialized towards psychological autonomy, i.e. the primacy of own intentions, wishes, individual preferences and emotions affording a definition of relatedness as psychological negotiable construct. Non-Western subsistence farmer children are socialized towards hierarchical relatedness, i.e. positioning oneself into the hierarchical structure of a communal system affording a definition of autonomy as action oriented, based on responsibility and obligations. Infancy can be regarded as a cultural lens through which to study the different socialization agendas. Parenting strategies that aim at supporting these different socialization goals in German and Euro-American parents on the one hand and Nso farmers from North Western Cameroon on the other hand are described. It is concluded that different pathways need to be considered in order to understand human psychology from a global perspective. © 2015 The Author(s).

  20. DMPD: Developmental plasticity of lymphocytes. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 18472258 Developmental plasticity of lymphocytes. Cobaleda C, Busslinger M. Curr Op...in Immunol. 2008 Apr;20(2):139-48. Epub 2008 May 9. (.png) (.svg) (.html) (.csml) Show Developmental plastic...ity of lymphocytes. PubmedID 18472258 Title Developmental plasticity of lymphocytes. Authors Cobaleda C, Bus

  1. Influence of gap-scale disturbance on developmental and successional pathways in Quercus-Pinus stands

    Science.gov (United States)

    T.A. Weber; J.L. Hart; C. Schweitzer; D.C. Dey

    2014-01-01

    Quercus-Pinus forests of the eastern USA cover millions of hectares and span a variety of ecoregions. Understanding the influence of natural disturbance on developmental and successional pathways is important for managers that wish to sustain Pinus spp. in these mixtures. Quantifying developmental and successional patterns in this...

  2. The effect of host developmental stage at parasitism on sex-related size differentiation in a larval endoparasitoid

    NARCIS (Netherlands)

    Gols, R.; Harvey, J.A.

    2009-01-01

    1. For their larval development, parasitoids depend on the quality and quantity of resources provided by a single host. Therefore, a close relationship is predicted between the size of the host at parasitism and the size of the emerging adult wasp. This relationship is less clear for koinobiont than

  3. Developmental pathways in infants from 4 to 24 months.

    Science.gov (United States)

    Valla, L; Birkeland, M S; Hofoss, D; Slinning, K

    2017-07-01

    There has been limited epidemiological research describing population-based samples regarding developmental pathways throughout infancy, and the research that exists has revealed substantial diversity. Identifying predictors for developmental pathways can inform early intervention services. The Ages and Stages Questionnaire was used to measure communication, gross motor, fine motor, problem-solving and personal-social skills longitudinally in a large, population-based sample of 1555 infants recruited from well-baby clinics in five municipalities in southeast Norway. We conducted latent class analyses to identify common pathways within the five developmental areas. Our results indicated that most classes of infants showed generally positive and stable normative developmental pathways. However, for communication and gross motor areas, more heterogeneity was found. For gross motor development, a class of 10% followed a U-shaped curve. A class of 8% had a declining communication pathway and did not reach the level of the high stable communication class at 24 months. Low gestational age, low Apgar score, male sex, maternal depression symptoms, non-Scandinavian maternal ethnicity and high maternal education significantly predict less beneficial communication pathways. The results suggest that infants with low gestational age, low Apgar score, male sex and a mother with depression symptoms or non-Scandinavian ethnicity may be at risk of developing less beneficial developmental pathways, especially within the communication area. Targeting these infants for surveillance and support might be protective against delayed development in several areas during a critical window of development. © 2017 John Wiley & Sons Ltd.

  4. Developmental Pathways to Conduct Disorder: Implications for Future Directions in Research, Assessment, and Treatment

    Science.gov (United States)

    Frick, Paul J.

    2012-01-01

    Research has indicated that there are several common pathways through which children and adolescents develop conduct disorder, each with different risk factors and each with different underlying developmental mechanisms leading to the child's aggressive and antisocial behavior. The current article briefly summarizes research on these pathways,…

  5. Developmental and hormone-induced changes of mitochondrial electron transport chain enzyme activities during the last instar larval development of maize stem borer, Chilo partellus (Lepidoptera: Crambidae).

    Science.gov (United States)

    VenkatRao, V; Chaitanya, R K; Naresh Kumar, D; Bramhaiah, M; Dutta-Gupta, A

    2016-12-01

    The energy demand for structural remodelling in holometabolous insects is met by cellular mitochondria. Developmental and hormone-induced changes in the mitochondrial respiratory activity during insect metamorphosis are not well documented. The present study investigates activities of enzymes of mitochondrial electron transport chain (ETC) namely, NADH:ubiquinone oxidoreductase or complex I, Succinate: ubiquinone oxidoreductase or complex II, Ubiquinol:ferricytochrome c oxidoreductase or complex III, cytochrome c oxidase or complex IV and F 1 F 0 ATPase (ATPase), during Chilo partellus development. Further, the effect of juvenile hormone (JH) analog, methoprene, and brain and corpora-allata-corpora-cardiaca (CC-CA) homogenates that represent neurohormones, on the ETC enzyme activities was monitored. The enzymatic activities increased from penultimate to last larval stage and thereafter declined during pupal development with an exception of ATPase which showed high enzyme activity during last larval and pupal stages compared to the penultimate stage. JH analog, methoprene differentially modulated ETC enzyme activities. It stimulated complex I and IV enzyme activities, but did not alter the activities of complex II, III and ATPase. On the other hand, brain homogenate declined the ATPase activity while the injected CC-CA homogenate stimulated complex I and IV enzyme activities. Cumulatively, the present study is the first to show that mitochondrial ETC enzyme system is under hormone control, particularly of JH and neurohormones during insect development. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Identification of Wnt Pathway Target Genes Regulating the Division and Differentiation of Larval Seam Cells and Vulval Precursor Cells in Caenorhabditis elegans.

    Science.gov (United States)

    Gorrepati, Lakshmi; Krause, Michael W; Chen, Weiping; Brodigan, Thomas M; Correa-Mendez, Margarita; Eisenmann, David M

    2015-06-05

    The evolutionarily conserved Wnt/β-catenin signaling pathway plays a fundamental role during metazoan development, regulating numerous processes including cell fate specification, cell migration, and stem cell renewal. Wnt ligand binding leads to stabilization of the transcriptional effector β-catenin and upregulation of target gene expression to mediate a cellular response. During larval development of the nematode Caenorhabditis elegans, Wnt/β-catenin pathways act in fate specification of two hypodermal cell types, the ventral vulval precursor cells (VPCs) and the lateral seam cells. Because little is known about targets of the Wnt signaling pathways acting during larval VPC and seam cell differentiation, we sought to identify genes regulated by Wnt signaling in these two hypodermal cell types. We conditionally activated Wnt signaling in larval animals and performed cell type-specific "mRNA tagging" to enrich for VPC and seam cell-specific mRNAs, and then used microarray analysis to examine gene expression compared to control animals. Two hundred thirty-nine genes activated in response to Wnt signaling were identified, and we characterized 50 genes further. The majority of these genes are expressed in seam and/or vulval lineages during normal development, and reduction of function for nine genes caused defects in the proper division, fate specification, fate execution, or differentiation of seam cells and vulval cells. Therefore, the combination of these techniques was successful at identifying potential cell type-specific Wnt pathway target genes from a small number of cells and at increasing our knowledge of the specification and behavior of these C. elegans larval hypodermal cells. Copyright © 2015 Gorrepati et al.

  7. Developmental pathways of fitness, and not baseline, predict fitness status at the end of childhood

    OpenAIRE

    Rodrigues, Luis Paulo; Stodden, David F.; Lopes, Vítor P.

    2013-01-01

    It is generally described that children fitness levels increase along childhood. Complementary to this idea is the notion that the tracking of children’s fitness is good to moderate during this developmental time, and that baseline (initial values) of fitness are determinant on fitness development. The importance of developmental pathways has been recently reinforced by a theoretical argument that predicts that healthy lifestyle trajectories will evolve through either a positive or n...

  8. Anthropogenic host plant expansion leads a nettle-feeding butterfly out of the forest: consequences for larval survival and developmental plasticity in adult morphology.

    Science.gov (United States)

    Merckx, Thomas; Serruys, Mélanie; Van Dyck, Hans

    2015-04-01

    Recent anthropogenic eutrophication has meant that host plants of nettle-feeding insects became quasi-omnipresent in fertile regions of Western Europe. However, host plant resource quality - in terms of microclimate and nutritional value - may vary considerably between the 'original' forest habitat and 'recent' agricultural habitat. Here, we compared development in both environmental settings using a split-brood design, so as to explore to what extent larval survival and adult morphology in the nettle-feeding butterfly Aglais urticae are influenced by the anthropogenic environment. Nettles along field margins had higher C/N ratios and provided warmer microclimates to larvae. Larvae developed 20% faster and tended to improve their survival rates, on the agricultural land compared to woodland. Our split-brood approach indicated plastic responses within families, but also family effects in the phenotypic responses. Adult males and females had darker wing pigmentation in the drier and warmer agricultural environment, which contrasts with the thermal melanism hypothesis. Developmental plasticity in response to this microclimatically different and more variable habitat was associated with a broader phenotypic parameter space for the species. Both habitat expansion and developmental plasticity are likely contributors to the ecological and evolutionary success of these nettle-feeding insects in anthropogenic environments under high nitrogen load.

  9. Developmental Transcriptome Analysis and Identification of Genes Involved in Larval Metamorphosis of the Razor Clam, Sinonovacula constricta.

    Science.gov (United States)

    Niu, Donghong; Wang, Fei; Xie, Shumei; Sun, Fanyue; Wang, Ze; Peng, Maoxiao; Li, Jiale

    2016-04-01

    The razor clam Sinonovacula constricta is an important commercial species. The deficiency of developmental transcriptomic data is becoming the bottleneck of further researches on the mechanisms underlying settlement and metamorphosis in early development. In this study, de novo transcriptome sequencing was performed for S. constricta at different early developmental stages by using Illumina HiSeq 2000 paired-end (PE) sequencing technology. A total of 112,209,077 PE clean reads were generated. De novo assembly generated 249,795 contigs with an average length of 585 bp. Gene annotation resulted in the identification of 22,870 unigene hits against the NCBI database. Eight unique sequences related to metamorphosis were identified and analyzed using real-time PCR. The razor clam reference transcriptome would provide useful information on early developmental and metamorphosis mechanisms and could be used in the genetic breeding of shellfish.

  10. Evolution of branched regulatory genetic pathways: directional selection on pleiotropic loci accelerates developmental system drift.

    Science.gov (United States)

    Johnson, Norman A; Porter, Adam H

    2007-01-01

    Developmental systems are regulated by a web of interacting loci. One common and useful approach in studying the evolution of development is to focus on classes of interacting elements within these systems. Here, we use individual-based simulations to study the evolution of traits controlled by branched developmental pathways involving three loci, where one locus regulates two different traits. We examined the system under a variety of selective regimes. In the case where one branch was under stabilizing selection and the other under directional selection, we observed "developmental system drift": the trait under stabilizing selection showed little phenotypic change even though the loci underlying that trait showed considerable evolutionary divergence. This occurs because the pleiotropic locus responds to directional selection and compensatory mutants are then favored in the pathway under stabilizing selection. Though developmental system drift may be caused by other mechanisms, it seems likely that it is accelerated by the same underlying genetic mechanism as that producing the Dobzhansky-Muller incompatibilities that lead to speciation in both linear and branched pathways. We also discuss predictions of our model for developmental system drift and how different selective regimes affect probabilities of speciation in the branched pathway system.

  11. Use of an activated beta-catenin to identify Wnt pathway target genes in caenorhabditis elegans, including a subset of collagen genes expressed in late larval development.

    Science.gov (United States)

    Jackson, Belinda M; Abete-Luzi, Patricia; Krause, Michael W; Eisenmann, David M

    2014-04-16

    The Wnt signaling pathway plays a fundamental role during metazoan development, where it regulates diverse processes, including cell fate specification, cell migration, and stem cell renewal. Activation of the beta-catenin-dependent/canonical Wnt pathway up-regulates expression of Wnt target genes to mediate a cellular response. In the nematode Caenorhabditis elegans, a canonical Wnt signaling pathway regulates several processes during larval development; however, few target genes of this pathway have been identified. To address this deficit, we used a novel approach of conditionally activated Wnt signaling during a defined stage of larval life by overexpressing an activated beta-catenin protein, then used microarray analysis to identify genes showing altered expression compared with control animals. We identified 166 differentially expressed genes, of which 104 were up-regulated. A subset of the up-regulated genes was shown to have altered expression in mutants with decreased or increased Wnt signaling; we consider these genes to be bona fide C. elegans Wnt pathway targets. Among these was a group of six genes, including the cuticular collagen genes, bli-1 col-38, col-49, and col-71. These genes show a peak of expression in the mid L4 stage during normal development, suggesting a role in adult cuticle formation. Consistent with this finding, reduction of function for several of the genes causes phenotypes suggestive of defects in cuticle function or integrity. Therefore, this work has identified a large number of putative Wnt pathway target genes during larval life, including a small subset of Wnt-regulated collagen genes that may function in synthesis of the adult cuticle.

  12. The child and the family: interdependence in developmental pathways

    Directory of Open Access Journals (Sweden)

    Kurt Kreppner

    Full Text Available This contribution focuses on the family as the major context for children's development, it includes concepts of the family as an institution for the transmission of meaning on the one hand, and it formulates implications for new theoretical and methodological approaches in the field of family research on the other. The idea of transmission of a society's meaning system via the family is discussed under the perspective that the socialization of children in the family provides a continuous basis for the aggregation of common knowledge over generations. The systems approach is taken as a promising model for dealing with the complex continuity and change issues during development. Data will be presented from two longitudinal studies, in which parent-child communication behavior was analyzed over time during two critical developmental periods, during the first two years after the birth of a second child and during the transition from childhood to adolescence.

  13. Heterogeneity among Peer-Rejected Boys across Middle Childhood: Developmental Pathways of Social Behavior.

    Science.gov (United States)

    Haselager, Gerbert J. T.; Cillessen, Antonius H. N.; Van Lieshout, Cornelius F. M.; Riksen-Walraven, J. Marianne A.; Hartup, Willard W.

    2002-01-01

    This longitudinal study identified subgroups of rejected boys with different developmental pathways of aggression and prosocial behavior during middle childhood. Four subgroups were identified associated with different patterns of sociometric acceptance and rejection over time and with social emotional adjustment in the last measurement wave.…

  14. Promoting Student Learning and Productive Persistence in Developmental Mathematics: Research Frameworks Informing the Carnegie Pathways

    Science.gov (United States)

    Edwards, Ann R.; Beattie, Rachel L.

    2016-01-01

    This paper focuses on two research-based frameworks that inform the design of instruction and promote student success in accelerated, developmental mathematics pathways. These are Learning Opportunities--productive struggle on challenging and relevant tasks, deliberate practice, and explicit connections, and Productive Persistence--promoting…

  15. Developmental Pathways Linking Externalizing Symptoms, Internalizing Symptoms, and Academic Competence to Adolescent Substance Use

    Science.gov (United States)

    Englund, Michelle M.; Siebenbruner, Jessica

    2012-01-01

    This study extends previous research investigating the developmental pathways predicting adolescent alcohol and marijuana use by examining the cascading effects of externalizing and internalizing symptoms and academic competence in the prediction of use and level of use of these substances in adolescence. Participants (N = 191) were drawn from a…

  16. Linking Social Change and Developmental Change: Shifting Pathways of Human Development

    Science.gov (United States)

    Greenfield, Patricia M.

    2009-01-01

    P. M. Greenfield's new theory of social change and human development aims to show how changing sociodemographic ecologies alter cultural values and learning environments and thereby shift developmental pathways. Worldwide sociodemographic trends include movement from rural residence, informal education at home, subsistence economy, and…

  17. Natural Larval Diet Differently Influences the Pattern of Developmental Changes in DNA 5-Methylcytosine Levels in Apis mellifera Queens as Compared with Workers and Drones.

    Science.gov (United States)

    Strachecka, A; Olszewski, K; Bajda, M; Demetraki-Paleolog, J

    2015-08-01

    The principal mechanism of gene activation/silencing is DNA 5-methylcytosine methylation. This study was aimed at determining global DNA methylation levels in larvae, prepupae, pupae, and 1-day-old adults of Apis mellifera queens, workers and drones. The Imprint Methylated DNA Quantification Kit MDQ1 was used. Percentages of DNA 5-methylcytosine were low and relatively similar in the larvae of all the castes until 4th day of larval development (3-5%). However, they were higher in the drone and worker larvae than in the queen larvae. Generally, the developmental patterns of changes in the DNA methylation levels were different in the queens in comparison with the drones and workers. While methylation increased in the queens, it decreased in the drones and workers. Methylated DNA methylcytosine percentages and weights in the queen prepupae (15%, 9.18 ng) and pupae (21%, 10.74 ng) were, respectively, three and four times higher than in the worker/drone brood of the same age (2.5-4%, 0.03-0.07 ng). Only in the queens, after a substantial increase, did DNA methylation decrease almost twice between the pupal stage and queen emergence (from 21% and 10.74 ng to 12% and 6.78 ng). This finding seems very interesting, particularly for experimental gerontology.

  18. Distribution and abundance by larval developmental stages of Symphurus williamsi (Pleuronectiformes: Cynoglossidae in the Gulf of California

    Directory of Open Access Journals (Sweden)

    Gerardo Aceves-Medina

    2006-06-01

    Full Text Available Distribution and abundance of tonguefish larvae (Symphurus williamsi were analyzed from collections made during ten oceanographic surveys in the Gulf of California between 1984 and 1988. Larvae were found mainly during the summer months and the highest abundances were located in the warmer southern and central regions of the Gulf, but they were scarce in the northern portion. High abundance of preflexion larvae occurred in areas where the sea surface temperature was between 29 and 32°C. Distribution patterns according to developmental stage suggest spatial ontogenic segregation with the early larvae in the ocean area of the central and southern regions of the Gulf. Based on abundance of preflexion larvae as well as on signs of a short egg period of this species, spawns may occur between early and mid summer.

  19. Developmental evolutionary biology of the vertebrate ear: conserving mechanoelectric transduction and developmental pathways in diverging morphologies

    Science.gov (United States)

    Fritzsch, B.; Beisel, K. W.; Bermingham, N. A.

    2000-01-01

    This brief overview shows that a start has been made to molecularly dissect vertebrate ear development and its evolutionary conservation to the development of the insect hearing organ. However, neither the patterning process of the ear nor the patterning process of insect sensory organs is sufficiently known at the moment to provide more than a first glimpse. Moreover, hardly anything is known about otocyst development of the cephalopod molluscs, another triploblast lineage that evolved complex 'ears'. We hope that the apparent conserved functional and cellular components present in the ciliated sensory neurons/hair cells will also be found in the genes required for vertebrate ear and insect sensory organ morphogenesis (Fig. 3). Likewise, we expect that homologous pre-patterning genes will soon be identified for the non-sensory cell development, which is more than a blocking of neuronal development through the Delta/Notch signaling system. Generation of the apparently unique ear could thus represent a multiplication of non-sensory cells by asymmetric and symmetric divisions as well as modification of existing patterning process by implementing novel developmental modules. In the final analysis, the vertebrate ear may come about by increasing the level of gene interactions in an already existing and highly conserved interactive cascade of bHLH genes. Since this was apparently achieved in all three lineages of triploblasts independently (Fig. 3), we now need to understand how much of the morphogenetic cascades are equally conserved across phyla to generate complex ears. The existing mutations in humans and mice may be able to point the direction of future research to understand the development of specific cell types and morphologies in the formation of complex arthropod, cephalopod, and vertebrate 'ears'.

  20. Pathways to psychosis: a comparison of the pervasive developmental disorder subtype Multiple Complex Developmental Disorder and the "At Risk Mental State"

    NARCIS (Netherlands)

    Sprong, M.; Becker, H. E.; Schothorst, P. F.; Swaab, H.; Ziermans, T. B.; Dingemans, P. M.; Linszen, D.; van Engeland, H.

    2008-01-01

    BACKGROUND: The comparison of high-risk populations with different developmental pathways to psychosis may lend more insight into the heterogeneity of the manifestation of the psychotic syndrome, and possible differing etiological pathways. AIM: To compare high-risk traits and symptoms in two

  1. Pathways to psychosis : A comparison of the pervasive developmental disorder subtype multiple complex developmental disorder and the "At Risk Mental State"

    NARCIS (Netherlands)

    Sprong, M.; Becker, H. E.; Schothorst, P. F.; Swaab, H.; Ziermans, T. B.; Dingemans, P. M.; Linszen, D.; van Engeland, I.

    Background: The comparison of high-risk populations with different developmental pathways to psychosis may lend more insight into the heterogeneity of the manifestation of the psychotic syndrome, and possible differing etiological pathways. Aim: To compare high-risk traits and symptoms in two

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

    Science.gov (United States)

    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.

  3. Proteomic characterization of larval and adult developmental stages in Echinococcus granulosus reveals novel insight into host-parasite interactions.

    Science.gov (United States)

    Cui, Shu-Jian; Xu, Lei-Lei; Zhang, Ting; Xu, Ming; Yao, Jun; Fang, Cai-Yun; Feng, Zheng; Yang, Peng-Yuan; Hu, Wei; Liu, Feng

    2013-06-12

    Cystic hydatid disease is an important zoonosis caused by Echinococcus granulosus infection. The expression profiles of its parasitic life stages and host-Echinococcus interactions remain to be elucidated. Here, we identified 157 adult and 1588 protoscolex proteins (1610 in all), including 1290 novel identifications. Paramyosins and an antigen B (AgB) were the dominant adult proteins. Dog proteins (30) identified in adults indicated diminished local inflammation caused by adult infection. The protoscolex expresses proteins that have been reported to be antigens in other parasites, such as 6-phosphofructokinase and calcineurin B. Pathway analyses suggested that E. granulosus uses both aerobic and anaerobic carbohydrate metabolisms to generate ATP. E. granulosus expresses proteins involved in synthesis and metabolism of lipids or steroids. At least 339 of 390 sheep proteins identified in protoscolex were novel identifications not seen in previous analyses. IgGs and lambda light chains were the most abundant antibody species. Sheep proteins were enriched for detoxification pathways, implying that host detoxification effects play a central role during host-parasite interactions. Our study provides valuable data on E. granulosus expression characteristics, allowing novel insights into the molecular mechanisms involved in host-parasite interactions. In this study, the Echinococcus granulosus adult worm proteome was analyzed for the first time. The protein identification of E. granulosus protoscoleces was extended dramatically. We also identified the most abundant host proteins co-purified with Echinococcus. The results provide useful information pertaining to the molecular mechanisms behind host-Echinococcus interaction and Echinococcus biology. This data also increases the potential for identifying vaccine candidates and new therapeutic targets, and may aid in the development of protein probes for selective and sensitive diagnosis of echinococcosis infection. In

  4. Developmental pathways from child maltreatment to adolescent marijuana dependence: Examining moderation by FKBP5

    Science.gov (United States)

    Handley, Elizabeth D.; Rogosch, Fred A.; Cicchetti, Dante

    2015-01-01

    The current study examined the prospective association between child maltreatment and the development of substance use disorder (SUD) in adolescence with the aim of investigating pathways underlying this relation, as well as genetic moderation of these developmental mechanisms. Specifically, we tested whether youth who experienced maltreatment prior to age 8 were at risk for the development of marijuana dependence in adolescence by way of a childhood externalizing pathway and a childhood internalizing pathway. Moreover, we tested whether variation in FKBP5 CATT haplotype moderated these pathways. The participants were 326 children (n=179 maltreated; n=147 nonmaltreated) assessed across two waves of data collection (childhood: ages 7–9 and adolescence: ages 15–18). Results indicated that higher levels of child externalizing symptoms significantly mediated the effect of child maltreatment on adolescent marijuana dependence symptoms for individuals with 1–2 copies of the FKBP5 CATT haplotype only. We did not find support for an internalizing pathway from child maltreatment to adolescent marijuana dependence, nor did we find evidence of moderation of the internalizing pathway by FKBP5 haplotype variation. Findings extend previous research by demonstrating that whether a maltreated child will traverse an externalizing pathway toward SUD in adolescence is dependent on FKBP5 genetic variation. PMID:26535939

  5. Male adolescent rites of passage: positive visions of multiple developmental pathways.

    Science.gov (United States)

    Pollack, William S

    2004-12-01

    Unlike the separation-based, stereotyped views of boys' developmental movement into adulthood, this paper will argue that there are more modern and relational models, as well as multiple pathways, for young males to journey through such rites of passage. Indeed, it will be suggested and supported by both qualitative and quantitative data that the more classic models depend on a "boy code" of traumatic separation from mother and the feminine, a process that is not only negative rather than positive in its developmental trajectory, but also likely to create a premature traumatic separation, leaving boys at risk for emotional maladjustment, everyday sadness, increased incidence of depression and the potential for violence toward the self, suicide, as well as violence toward others. More-positive visions and versions of male rites of passage will be posited and described. The definition of emotional "resilience" during this significant period will be re-addressed as one of "healthy vulnerability," sustained through connection to loving adults, rather than a classic belief in stoicism and release from relational ties. Attachment theory will be brought to bear and the desperate yearnings of adolescent males not only for connection to adult mentors, but also for non-romanticized friendships with adolescent females, will be discussed. Finally, the understanding and substitution of these new, more positive, developmental pathways will be linked to the prevention of violence.

  6. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Directory of Open Access Journals (Sweden)

    Andrew Oliphant

    Full Text Available Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C. We conclude that at settlement P. varians juveniles do not follow the temperature-size rule

  7. The implications of temperature-mediated plasticity in larval instar number for development within a marine invertebrate, the shrimp Palaemonetes varians.

    Science.gov (United States)

    Oliphant, Andrew; Hauton, Chris; Thatje, Sven

    2013-01-01

    Variations in larval instar number are common among arthropods. Here, we assess the implications of temperature-mediated variations in larval instar number for larval development time, larval growth rates, and juvenile dry weight within the palaemonid shrimp, Palaemonetes varians. In contrast with previous literature, which focuses on terrestrial arthropods, particularly model and pest species often of laboratory lines, we use wild shrimp, which differ in their life history from previous models. Newly-hatched P. varians larvae were first reared at 5, 10, 17, 25, and 30 °C to assess their thermal scope for development. Larvae developed at 17, 25, and 30 °C. At higher temperatures, larvae developed through fewer larval instars. Two dominant developmental pathways were observed; a short pathway of four instars and a long pathway of five instars. Longer developmental pathways of six to seven instars were rarely observed (mostly at lower temperatures) and consisted of additional instars as 'repeat' instars; i.e. little developmental advance over the preceding instar. To assess the implications of temperature-mediated variation in larval instar number, newly-hatched larvae were then reared at 15, 20, and 25 °C. Again, the proportion of larvae developing through four instars increased with temperature. At all temperatures, larval development time and juvenile dry weight were greater for larvae developing through five instars. Importantly, because of the increasing proportion of larvae developing through four instars with increasing temperature, larval traits associated with this pathway (reduced development time and juvenile dry weight) became more dominant. As a consequence of increasing growth rate with temperature, and the shift in the proportion of larvae developing through four instars, juvenile dry weight was greatest at intermediate temperatures (20 °C). We conclude that at settlement P. varians juveniles do not follow the temperature-size rule; this is of

  8. Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors

    International Nuclear Information System (INIS)

    Hindriksen, Sanne; Bijlsma, Maarten F.

    2012-01-01

    Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer

  9. Proteomics insights: proteins related to larval attachment and metamorphosis of marine invertebrates

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2014-10-31

    The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTMs) are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  10. Proteomics Insights: Proteins related to Larval Attachment and Metamorphosis of Marine Invertebrates

    Directory of Open Access Journals (Sweden)

    KONDETHIMMANAHALLI eCHANDRAMOULI

    2014-10-01

    Full Text Available The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTM are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

  11. Proteomics insights: proteins related to larval attachment and metamorphosis of marine invertebrates

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Qian, Pei-Yuan; Ravasi, Timothy

    2014-01-01

    The transition in an animal from a pelagic larval stage to a sessile benthic juvenile typically requires major morphological and behavioral changes. Larval competency, attachment and initiation of metamorphosis are thought to be regulated by intrinsic chemical signals and specific sets of proteins. However, the molecular mechanisms that regulate larval attachment and metamorphosis in marine invertebrates have yet to be fully elucidated. Despite the many challenges associated with analysis of the larvae proteome, recent proteomic technologies have been used to address specific questions in larval developmental biology. These and other molecular studies have generated substantial amount of information of the proteins and molecular pathways involved in larval attachment and metamorphosis. Furthermore, the results of these studies have shown that systematic changes in protein expression patterns and post-translational modifications (PTMs) are crucial for the transition from larva to juvenile. The degeneration of larval tissues is mediated by protein degradation, while the development of juvenile organs may require PTM. In terms of application, the identified proteins may serve as targets for antifouling compounds, and biomarkers for environmental stressors. In this review we highlight the strengths and limitations of proteomic tools in the context of the study of marine invertebrate larval biology.

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

    Science.gov (United States)

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

    2018-06-01

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

  13. Priming 3D cultures of human mesenchymal stromal cells toward cartilage formation via developmental pathways.

    Science.gov (United States)

    Centola, Matteo; Tonnarelli, Beatrice; Schären, Stefan; Glaser, Nicolas; Barbero, Andrea; Martin, Ivan

    2013-11-01

    The field of regenerative medicine has increasingly recognized the importance to be inspired by developmental processes to identify signaling pathways crucial for 3D organogenesis and tissue regeneration. Here, we aimed at recapitulating the first events occurring during limb development (ie, cell condensation and expansion of an undifferentiated mesenchymal cell population) to prime 3D cultures of human bone marrow-derived mesenchymal stromal/stem cells (hBM-MSC) toward the chondrogenic route. Based on embryonic development studies, we hypothesized that Wnt3a and fibroblast growth factor 2 (FGF2) induce hBM-MSC to proliferate in 3D culture as an undifferentiated pool of progenitors (defined by clonogenic capacity and expression of typical markers), retaining chondrogenic potential upon induction by suitable morphogens. hBM-MSC were responsive to Wnt signaling in 3D pellet culture, as assessed by significant upregulation of main target genes and increase of unphosphorylated β-catenin levels. Wnt3a was able to induce a five-fold increase in the number of proliferating hBM-MSC (6.4% vs. 1.3% in the vehicle condition), although total DNA content of the 3D construct was decreasing over time. Preconditioning with Wnt3a improved transforming growth factor-β1 mediated chondrogenesis (30% more glycosaminoglycans/cell in average). In contrast to developmental and 2D MSC culture models, FGF2 antagonized the Wnt-mediated effects. Interestingly, the CD146⁺ subpopulation was found to be more responsive to Wnt3a. The presented data indicate a possible strategy to prime 3D cultures of hBM-MSC by invoking a "developmental engineering" approach. The study also identifies some opportunities and challenges to cross-fertilize skeletal development models and 3D hBM-MSC culture systems.

  14. Distinct Signaling Mechanisms in Multiple Developmental Pathways by the SCRAMBLED Receptor of Arabidopsis1[OPEN

    Science.gov (United States)

    Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

    2014-01-01

    SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. PMID:25136062

  15. Distinct signaling mechanisms in multiple developmental pathways by the SCRAMBLED receptor of Arabidopsis.

    Science.gov (United States)

    Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

    2014-10-01

    SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. © 2014 American Society of Plant Biologists. All Rights Reserved.

  16. Anthropogenic host plant expansion leads a nettle-feeding butterfly out of the forest: consequences for larval survival and developmental plasticity in adult morphology

    OpenAIRE

    Merckx, Thomas; Serruys, Mélanie; Van Dyck, Hans

    2015-01-01

    Recent anthropogenic eutrophication has meant that host plants of nettle-feeding insects became quasi-omnipresent in fertile regions of Western Europe. However, host plant resource quality – in terms of microclimate and nutritional value – may vary considerably between the ‘original’ forest habitat and ‘recent’ agricul- tural habitat. Here, we compared development in both environmental settings using a split-brood design, so as to explore to what extent larval survival and adult morphology in...

  17. Developmental pathways from childhood conduct problems to early adult depression: findings from the ALSPAC cohort

    Science.gov (United States)

    Stringaris, Argyris; Lewis, Glyn; Maughan, Barbara

    2014-01-01

    Background Pathways from early-life conduct problems to young adult depression remain poorly understood. Aims To test developmental pathways from early-life conduct problems to depression at age 18. Method Data (n = 3542) came from the Avon Longitudinal Study of Parents and Children (ALSPAC). Previously derived conduct problem trajectories (ages 4-13 years) were used to examine associations with depression from ages 10 to 18 years, and the role of early childhood factors as potential confounders. Results Over 43% of young adults with depression in the ALSPAC cohort had a history of child or adolescent conduct problems, yielding a population attributable fraction of 0.15 (95% CI 0.08-0.22). The association between conduct problems and depression at age 18 was considerable even after adjusting for prior depression (odds ratio 1.55, 95% CI 1.24-1.94). Early-onset persistent conduct problems carried the highest risk for later depression. Irritability characterised depression for those with a history of conduct problems. Conclusions Early-life conduct problems are robustly associated with later depressive disorder and may be useful targets for early intervention. PMID:24764545

  18. Childhood adversity and conduct disorder: A developmental pathway to violence in schizophrenia.

    Science.gov (United States)

    Oakley, Clare; Harris, Stephanie; Fahy, Thomas; Murphy, Declan; Picchioni, Marco

    2016-04-01

    Both childhood adversity and conduct disorder are over-represented among adult patients with schizophrenia and have been proposed as significant factors that may increase the risk of violence. It is not known how childhood adversity and conduct disorder might interact to contribute towards an increased risk of violence in schizophrenia. This study aimed to explore the relationships between childhood adversity, conduct disorder and violence among men with schizophrenia. 54 male patients with schizophrenia from a range of inpatient and outpatient mental health services were assessed for exposure to a variety of childhood adversities, conduct disorder before the age of 15 and later violent behaviour in adulthood. Exposure to domestic violence during childhood was associated with an increased propensity to violence in adulthood. Symptoms of conduct disorder were associated both with cumulative exposure to childhood adversities and with later propensity to violence. The cumulative number of childhood adversities was associated with adult propensity to violence. This association was significantly attenuated by inclusion of conduct disorder in the model. This is the first study to demonstrate an association between childhood exposure to domestic violence and later violent behaviour in schizophrenia. Conduct disorder may mediate the association between cumulative childhood adversities and adult propensity to violence, indicating an indirect pathway. These results indicate a complex interplay between childhood adversity, conduct disorder and later violent behaviour in schizophrenia, and suggest that there may be shared aetiological risk factors on a common developmental pathway to violence. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Multiple Causal Links Between Magnocellular-Dorsal Pathway Deficit and Developmental Dyslexia.

    Science.gov (United States)

    Gori, Simone; Seitz, Aaron R; Ronconi, Luca; Franceschini, Sandro; Facoetti, Andrea

    2016-10-17

    Although impaired auditory-phonological processing is the most popular explanation of developmental dyslexia (DD), the literature shows that the combination of several causes rather than a single factor contributes to DD. Functioning of the visual magnocellular-dorsal (MD) pathway, which plays a key role in motion perception, is a much debated, but heavily suspected factor contributing to DD. Here, we employ a comprehensive approach that incorporates all the accepted methods required to test the relationship between the MD pathway dysfunction and DD. The results of 4 experiments show that (1) Motion perception is impaired in children with dyslexia in comparison both with age-match and with reading-level controls; (2) pre-reading visual motion perception-independently from auditory-phonological skill-predicts future reading development, and (3) targeted MD trainings-not involving any auditory-phonological stimulation-leads to improved reading skill in children and adults with DD. Our findings demonstrate, for the first time, a causal relationship between MD deficits and DD, virtually closing a 30-year long debate. Since MD dysfunction can be diagnosed much earlier than reading and language disorders, our findings pave the way for low resource-intensive, early prevention programs that could drastically reduce the incidence of DD. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

    International Nuclear Information System (INIS)

    Henrique Barreta, Marcos; Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de; Ferreira, Rogério; Oliveira, João Francisco de; Gonçalves, Paulo Bayard Dias; Bordignon, Vilceu

    2012-01-01

    This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

  1. Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

    Energy Technology Data Exchange (ETDEWEB)

    Henrique Barreta, Marcos [Universidade Federal de Santa Catarina, Campus Universitario de Curitibanos, Curitibanos, SC (Brazil); Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Ferreira, Rogerio [Centro de Educacao Superior do Oeste-Universidade do Estado de Santa Catarina, Chapeco, SC (Brazil); Oliveira, Joao Francisco de; Goncalves, Paulo Bayard Dias [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Bordignon, Vilceu, E-mail: vilceu.bordignon@mcgill.ca [Department of Animal Science, McGill University, Ste-Anne-De-Bellevue, QC (Canada)

    2012-10-01

    This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

  2. Developmental Pathways to Depressive Symptoms in Adolescence: A Multi-Wave Prospective Study of Negative Emotionality, Stressors, and Anxiety

    Science.gov (United States)

    Barrocas, Andrea L.; Hankin, Benjamin L.

    2011-01-01

    This study examined two potential developmental pathways through which the temperament risk factor of negative emotionality (NE) leads to prospective increases in depressive symptoms through the mediating role of stressors and anxious symptoms in a sample of early to middle adolescents (N = 350, 6th-10th graders). The primary hypothesized model…

  3. Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics

    International Nuclear Information System (INIS)

    Kleinstreuer, N.C.; Smith, A.M.; West, P.R.; Conard, K.R.; Fontaine, B.R.; Weir-Hauptman, A.M.; Palmer, J.A.; Knudsen, T.B.; Dix, D.J.; Donley, E.L.R.; Cezar, G.G.

    2011-01-01

    Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast™ chemical screening and prioritization research project. Metabolites from hES cultures were evaluated for known and novel signatures that may be indicative of developmental toxicity. Significant fold changes in endogenous metabolites were detected for 83 putatively annotated mass features in response to the subset of ToxCast chemicals. The annotations were mapped to specific human metabolic pathways. This revealed strong effects on pathways for nicotinate and nicotinamide metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and arginine and proline metabolism pathways. Predictivity for adverse outcomes in mammalian prenatal developmental toxicity studies used ToxRefDB and other sources of information, including Stemina Biomarker Discovery's predictive DevTox® model trained on 23 pharmaceutical agents of known developmental toxicity and differing potency. The model initially predicted developmental toxicity from the blinded ToxCast compounds in concordance with animal data with 73% accuracy. Retraining the model with data from the unblinded test compounds at one concentration level increased the predictive accuracy for the remaining concentrations to 83%. These preliminary results on a 11-chemical subset of the ToxCast chemical library indicate that metabolomics analysis of the hES secretome provides information valuable for predictive modeling and mechanistic understanding of mammalian developmental toxicity. -- Highlights: ► We tested 11 environmental compounds in a hESC metabolomics platform. ► Significant changes in secreted small molecule metabolites were observed. ► Perturbed mass features map to pathways critical for normal development and pregnancy. ► Arginine, proline, nicotinate, nicotinamide and glutathione pathways were affected.

  4. Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Kleinstreuer, N.C., E-mail: kleinstreuer.nicole@epa.gov [NCCT, US EPA, RTP, NC 27711 (United States); Smith, A.M.; West, P.R.; Conard, K.R.; Fontaine, B.R. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Weir-Hauptman, A.M. [Covance, Inc., Madison, WI 53704 (United States); Palmer, J.A. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Knudsen, T.B.; Dix, D.J. [NCCT, US EPA, RTP, NC 27711 (United States); Donley, E.L.R. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); Cezar, G.G. [Stemina Biomarker Discovery, Inc., Madison, WI 53719 (United States); University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2011-11-15

    Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast Trade-Mark-Sign chemical screening and prioritization research project. Metabolites from hES cultures were evaluated for known and novel signatures that may be indicative of developmental toxicity. Significant fold changes in endogenous metabolites were detected for 83 putatively annotated mass features in response to the subset of ToxCast chemicals. The annotations were mapped to specific human metabolic pathways. This revealed strong effects on pathways for nicotinate and nicotinamide metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and arginine and proline metabolism pathways. Predictivity for adverse outcomes in mammalian prenatal developmental toxicity studies used ToxRefDB and other sources of information, including Stemina Biomarker Discovery's predictive DevTox Registered-Sign model trained on 23 pharmaceutical agents of known developmental toxicity and differing potency. The model initially predicted developmental toxicity from the blinded ToxCast compounds in concordance with animal data with 73% accuracy. Retraining the model with data from the unblinded test compounds at one concentration level increased the predictive accuracy for the remaining concentrations to 83%. These preliminary results on a 11-chemical subset of the ToxCast chemical library indicate that metabolomics analysis of the hES secretome provides information valuable for predictive modeling and mechanistic understanding of mammalian developmental toxicity. -- Highlights: Black-Right-Pointing-Pointer We tested 11 environmental compounds in a hESC metabolomics platform. Black-Right-Pointing-Pointer Significant changes in secreted small molecule metabolites were observed. Black-Right-Pointing-Pointer Perturbed mass features map to pathways critical for normal

  5. Exposure to PFOS, PFHxS, or PFHxA, but not GenX, Nafion BP1, or ADONA, Elicits Developmental Neurotoxicity in Larval Zebrafish

    Science.gov (United States)

    Exposure to polyfluoroalkyl substances (PFAS) like perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) are associated with developmental toxicity, neurotoxicity, and carcinogenesis. Legacy PFAS have therefore been replaced with shorter carbon chain and polyfluor...

  6. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan

    2011-07-29

    Background: The barnacle Balanus amphitrite is a globally distributed biofouler and a model species in intertidal ecology and larval settlement studies. However, a lack of genomic information has hindered the comprehensive elucidation of the molecular mechanisms coordinating its larval settlement. The pyrosequencing-based transcriptomic approach is thought to be useful to identify key molecular changes during larval settlement. Methodology and Principal Findings: Using 454 pyrosequencing, we collected totally 630,845 reads including 215,308 from the larval stages and 415,537 from the adults; 23,451 contigs were generated while 77,785 remained as singletons. We annotated 31,720 of the 92,322 predicted open reading frames, which matched hits in the NCBI NR database, and identified 7,954 putative genes that were differentially expressed between the larval and adult stages. Of these, several genes were further characterized with quantitative real-time PCR and in situ hybridization, revealing some key findings: 1) vitellogenin was uniquely expressed in late nauplius stage, suggesting it may be an energy source for the subsequent non-feeding cyprid stage; 2) the locations of mannose receptors suggested they may be involved in the sensory system of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval settlement. Conclusions: Our results provide not only the basis of several new hypotheses about gene functions during larval settlement, but also the availability of this large transcriptome dataset in B. amphitrite for further exploration of larval settlement and developmental pathways in this important marine species. © 2011 Chen et al.

  7. The expression of petunia strigolactone pathway genes is altered as part of the endogenous developmental program

    Directory of Open Access Journals (Sweden)

    Revel S M Drummond

    2012-01-01

    Full Text Available Analysis of mutants with increased branching has revealed the strigolactone synthesis/perception pathway which regulates branching in plants. However, whether variation in this well conserved developmental signalling system contributes to the unique plant architectures of different species is yet to be determined. We examined petunia orthologues of the Arabidopsis MAX1 and MAX2 genes to characterise their role in petunia architecture. A single orthologue of MAX1, PhMAX1 which encodes a cytochrome P450, was identified and was able to complement the max1 mutant of Arabidopsis. Petunia has two copies of the MAX2 gene, PhMAX2A and PhMAX2B which encode F-Box proteins. Differences in the transcript levels of these two MAX2-like genes suggest diverging functions. Unlike PhMAX2B, PhMAX2A mRNA levels increase as leaves age. Nonetheless, this gene functionally complements the Arabidopsis max2 mutant indicating that the biochemical activity of the PhMAX2A protein is not significantly different from MAX2. The expression of the petunia strigolactone pathway genes (PhCCD7, PhCCD8, PhMAX1, PhMAX2A, and PhMAX2B was then further investigated throughout the development of wild-type petunia plants. Three of these genes showed changes in mRNA levels over the development series. Alterations to the expression of these genes over time, or in different regions of the plant, may influence the branching growth habit of the plant. Alterations to strigolactone production and/or sensitivity could allow both subtle and dramatic changes to branching within and between species.

  8. Developmental Pathways for Social Understanding: Linking Social Cognition to Social Contexts

    Directory of Open Access Journals (Sweden)

    Kimberly eBrink

    2015-05-01

    Full Text Available Contemporary research, often with looking-time tasks, reveals that infants possess foundational understandings of their social worlds. However, few studies have examined how these early social cognitions relate to the child’s social interactions and behavior in early development. Does an early understanding of the social world relate to how an infant interacts with his or her parents? Do early social interactions along with social-cognitive understandings in infancy predict later preschool social competencies? In the current paper, we propose a theory in which children’s later social behaviors and their understanding of the social world depend on the integration of early social understanding and experiences in infancy. We review several of our studies, as well as other research, that directly examine the pathways between these competencies to support a hypothesized network of relations between social-cognitive development and social-interactive behaviors in the development from infancy to childhood. In total, these findings reveal differences in infant social competences that both track the developmental trajectory of infants’ understanding of people over the first years of life and provide external validation for the large body of social-cognitive findings emerging from laboratory looking-time paradigms.

  9. Developmental Pathways from Child Maltreatment to Adolescent Substance Use: The Roles of Posttraumatic Stress Symptoms and Mother-Child Relationships

    Science.gov (United States)

    Yoon, Susan; Kobulsky, Julia M.; Yoon, Dalhee; Kim, Wonhee

    2018-01-01

    While many studies have identified a significant relation between child maltreatment and adolescent substance use, the developmental pathways linking this relation remain sparsely explored. The current study examines posttraumatic stress (PTS) symptoms, mother-child relationships, and internalizing and externalizing problems as potential longitudinal pathways through which child maltreatment influences adolescent substance use. Structural equation modeling was conducted on 883 adolescents drawn from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN). The pathways of PTS symptoms linked physical and sexual abuse to substance use, and the pathways of mother-child relationships linked emotional abuse and neglect to substance use. None of the four types of maltreatment affected substance use via internalizing or externalizing problems. The findings suggest that intervention efforts aimed at addressing posttraumatic stress symptoms and improving mother-child relationship quality may be beneficial in reducing substance use among adolescents with child maltreatment histories. PMID:29503490

  10. Developmental pathways of change in health-related fitness and motor competence are related to obesity development in childhood

    OpenAIRE

    Rodrigues, Luis Paulo; Lopes, Vítor P.

    2013-01-01

    The epidemic obesity in chi1dhood is well acknowledged worldwide. Althongh researchers agree that explaining models for childhood obesity can include several risk factors, the question remains as to which speci fic predictors can be the touchstone to solving the probIem. In recent years, a modeI of developmental mechanisms influencing the physical activity and weight pathways of children has been presented by Stodden and colleagnes (2008). In this model it is predicted that children ...

  11. Neurotoxicity of developmental hypothyroxinemia and hypothyroidism in rats: Impairments of long-term potentiation are mediated by phosphatidylinositol 3-kinase signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yi; Wei, Wei; Wang, Yuan; Dong, Jing; Song, Binbin; Min, Hui [Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang (China); Teng, Weiping, E-mail: twpendocrine@yahoo.com.cn [Liaoning Provincial Key Laboratory of Endocrine Diseases, the First Hospital of China Medical University, Shenyang (China); Chen, Jie, E-mail: chenjie@mail.cmu.edu.cn [Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang (China)

    2013-09-01

    Neurotoxicity of iodine deficiency-induced hypothyroidism during developmental period results in serious impairments of brain function, such as learning and memory. These impairments are largely irreversible, and the underlying mechanisms remain unclear. In addition to hypothyroidism, iodine deficiency may cause hypothyroxinemia, a relatively subtle form of thyroid hormone deficiency. Neurotoxicity of developmental hypothyroxinemia also potentially impairs learning and memory. However, more direct evidence of the associations between developmental hypothyroxinemia and impairments of learning and memory should be provided, and the underlying mechanisms remain to be elucidated. Thus, in the present study, we investigated the effects of developmental hypothyroxinemia and hypothyroidism on long-term potentiation (LTP), a widely accepted cellular model of learning and memory, in the hippocampal CA1 region. The activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway – a pathway closely associated with synaptic plasticity and learning and memory – was also investigated. Wistar rats were treated with iodine deficient diet or methimazole (MMZ) to induce developmental hypothyroxinemia or hypothyroidism. The results showed that developmental hypothyroxinemia caused by mild iodine deficiency and developmental hypothyroidism caused by severe iodine deficiency or MMZ significantly reduced the field-excitatory postsynaptic potential (f-EPSP) slope and the population spike (PS) amplitude. Decreased activation of the PI3K signaling pathway was also observed in rats subjected to developmental hypothyroxinemia or hypothyroidism. Our results may support the hypothesis that neurotoxicity of both developmental hypothyroxinemia and hypothyroidism causes damages to learning and memory. Our results also suggest that decreased activation of the PI3K signaling pathway may contribute to impairments of LTP caused by neurotoxicity of both developmental hypothyroxinemia and

  12. Neurotoxicity of developmental hypothyroxinemia and hypothyroidism in rats: Impairments of long-term potentiation are mediated by phosphatidylinositol 3-kinase signaling pathway

    International Nuclear Information System (INIS)

    Wang, Yi; Wei, Wei; Wang, Yuan; Dong, Jing; Song, Binbin; Min, Hui; Teng, Weiping; Chen, Jie

    2013-01-01

    Neurotoxicity of iodine deficiency-induced hypothyroidism during developmental period results in serious impairments of brain function, such as learning and memory. These impairments are largely irreversible, and the underlying mechanisms remain unclear. In addition to hypothyroidism, iodine deficiency may cause hypothyroxinemia, a relatively subtle form of thyroid hormone deficiency. Neurotoxicity of developmental hypothyroxinemia also potentially impairs learning and memory. However, more direct evidence of the associations between developmental hypothyroxinemia and impairments of learning and memory should be provided, and the underlying mechanisms remain to be elucidated. Thus, in the present study, we investigated the effects of developmental hypothyroxinemia and hypothyroidism on long-term potentiation (LTP), a widely accepted cellular model of learning and memory, in the hippocampal CA1 region. The activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway – a pathway closely associated with synaptic plasticity and learning and memory – was also investigated. Wistar rats were treated with iodine deficient diet or methimazole (MMZ) to induce developmental hypothyroxinemia or hypothyroidism. The results showed that developmental hypothyroxinemia caused by mild iodine deficiency and developmental hypothyroidism caused by severe iodine deficiency or MMZ significantly reduced the field-excitatory postsynaptic potential (f-EPSP) slope and the population spike (PS) amplitude. Decreased activation of the PI3K signaling pathway was also observed in rats subjected to developmental hypothyroxinemia or hypothyroidism. Our results may support the hypothesis that neurotoxicity of both developmental hypothyroxinemia and hypothyroidism causes damages to learning and memory. Our results also suggest that decreased activation of the PI3K signaling pathway may contribute to impairments of LTP caused by neurotoxicity of both developmental hypothyroxinemia and

  13. Developmental transcriptomic analyses for mechanistic insights into critical pathways involved in embryogenesis of pelagic mahi-mahi (Coryphaena hippurus.

    Directory of Open Access Journals (Sweden)

    Elvis Genbo Xu

    Full Text Available Mahi-mahi (Coryphaena hippurus is a commercially and ecologically important species of fish occurring in tropical and temperate waters worldwide. Understanding early life events is crucial for predicting effects of environmental stress, which is largely restricted by a lack of genetic resources regarding expression of early developmental genes and regulation of pathways. The need for anchoring developmental stages to transcriptional activities is highlighted by increasing evidence on the impacts of recurrent worldwide oil spills in this sensitive species during early development. By means of high throughput sequencing, we characterized the developmental transcriptome of mahi-mahi at three critical developmental stages, from pharyngula embryonic stage (24 hpf to 48 hpf yolk-sac larva (transition 1, and to 96 hpf free-swimming larva (transition 2. With comparative analysis by multiple bioinformatic tools, a larger number of significantly altered genes and more diverse gene ontology terms were observed during transition 2 than transition 1. Cellular and tissue development terms were more significantly enriched in transition 1, while metabolism related terms were more enriched in transition 2, indicating a switch progressing from general embryonic development to metabolism during the two transitions. Special focus was given on the most significant common canonical pathways (e.g. calcium signaling, glutamate receptor signaling, cAMP response element-binding protein signaling, cardiac β-adrenergic signaling, etc. and expression of developmental genes (e.g. collagens, myosin, notch, glutamate metabotropic receptor etc., which were associated with morphological changes of nervous, muscular, and cardiovascular system. These data will provide an important basis for understanding embryonic development and identifying molecular mechanisms of abnormal development in fish species.

  14. Developmental pathways from child maltreatment to adolescent marijuana dependence: Examining moderation by FK506 binding protein 5 gene (FKBP5).

    Science.gov (United States)

    Handley, Elizabeth D; Rogosch, Fred A; Cicchetti, Dante

    2015-11-01

    The current study examined the prospective association between child maltreatment and the development of substance use disorder in adolescence with the aim of investigating pathways underlying this relation, as well as genetic moderation of these developmental mechanisms. Specifically, we tested whether youth who experienced maltreatment prior to age 8 were at risk for the development of marijuana dependence in adolescence by way of a childhood externalizing pathway and a childhood internalizing pathway. Moreover, we tested whether variation in FK506 binding protein 5 gene (FKBP5) CATT haplotype moderated these pathways. The participants were 326 children (n =179 maltreated; n = 147 nonmaltreated) assessed across two waves of data collection (childhood: ages 7-9 and adolescence: ages 15-18). Results indicated that higher levels of child externalizing symptoms significantly mediated the effect of child maltreatment on adolescent marijuana dependence symptoms for individuals with one or two copies of the FKBP5 CATT haplotype only. We did not find support for an internalizing pathway from child maltreatment to adolescent marijuana dependence, nor did we find evidence of moderation of the internalizing pathway by FKBP5 haplotype variation. Findings extend previous research by demonstrating that whether a maltreated child will traverse an externalizing pathway toward substance use disorder in adolescence is dependent on FKBP5 genetic variation.

  15. Developmental transcriptome of Aplysia californica'

    KAUST Repository

    Heyland, Andreas

    2010-12-06

    Genome-wide transcriptional changes in development provide important insight into mechanisms underlying growth, differentiation, and patterning. However, such large-scale developmental studies have been limited to a few representatives of Ecdysozoans and Chordates. Here, we characterize transcriptomes of embryonic, larval, and metamorphic development in the marine mollusc Aplysia californica and reveal novel molecular components associated with life history transitions. Specifically, we identify more than 20 signal peptides, putative hormones, and transcription factors in association with early development and metamorphic stages-many of which seem to be evolutionarily conserved elements of signal transduction pathways. We also characterize genes related to biomineralization-a critical process of molluscan development. In summary, our experiment provides the first large-scale survey of gene expression in mollusc development, and complements previous studies on the regulatory mechanisms underlying body plan patterning and the formation of larval and juvenile structures. This study serves as a resource for further functional annotation of transcripts and genes in Aplysia, specifically and molluscs in general. A comparison of the Aplysia developmental transcriptome with similar studies in the zebra fish Danio rerio, the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, and other studies on molluscs suggests an overall highly divergent pattern of gene regulatory mechanisms that are likely a consequence of the different developmental modes of these organisms. © 2010 Wiley-Liss, Inc., A Wiley Company.

  16. Gene expression analysis in human osteoblasts exposed to dexamethasone identifies altered developmental pathways as putative drivers of osteoporosis

    Directory of Open Access Journals (Sweden)

    Sadlier Denise M

    2007-02-01

    Full Text Available Abstract Background Osteoporosis, a disease of decreased bone mineral density represents a significant and growing burden in the western world. Aging population structure and therapeutic use of glucocorticoids have contributed in no small way to the increase in the incidence of this disease. Despite substantial investigative efforts over the last number of years the exact molecular mechanism underpinning the initiation and progression of osteoporosis remain to be elucidated. This has meant that no significant advances in therapeutic strategies have emerged, with joint replacement surgery being the mainstay of treatment. Methods In this study we have used an integrated genomics profiling and computational biology based strategy to identify the key osteoblast genes and gene clusters whose expression is altered in response to dexamethasone exposure. Primary human osteoblasts were exposed to dexamethasone in vitro and microarray based transcriptome profiling completed. Results These studies identified approximately 500 osteoblast genes whose expression was altered. Functional characterization of the transcriptome identified developmental networks as being reactivated with 106 development associated genes found to be differentially regulated. Pathway reconstruction revealed coordinate alteration of members of the WNT signaling pathway, including frizzled-2, frizzled-7, DKK1 and WNT5B, whose differential expression in this setting was confirmed by real time PCR. Conclusion The WNT pathway is a key regulator of skeletogenesis as well as differentiation of bone cells. Reactivation of this pathway may lead to altered osteoblast activity resulting in decreased bone mineral density, the pathological hallmark of osteoporosis. The data herein lend weight to the hypothesis that alterations in developmental pathways drive the initiation and progression of osteoporosis.

  17. The role of the PI3K-Akt signaling pathway in the developmental competence of bovine oocytes.

    Directory of Open Access Journals (Sweden)

    Gabriella Mamede Andrade

    Full Text Available The ovarian follicle encloses oocytes in a microenvironment throughout their growth and acquisition of competence. Evidence suggests a dynamic interplay among follicular cells and oocytes, since they are constantly exchanging "messages". We dissected bovine ovarian follicles and recovered follicular cells (FCs-granulosa and cumulus cells and cumulus-oocyte complexes (COCs to investigate whether the PI3K-Akt signaling pathway impacted oocyte quality. Following follicle rupture, COCs were individually selected for in vitro cultures to track the follicular cells based on oocyte competence to reach the blastocyst stage after parthenogenetic activation. Levels of PI3K-Akt signaling pathway components in FCs correlated with oocyte competence. This pathway is upregulated in FCs from follicles with high-quality oocytes that are able to reach the blastocyst stage, as indicated by decreased levels of PTEN and increased levels of the PTEN regulators bta-miR-494 and bta-miR-20a. Using PI3K-Akt responsive genes, we showed decreased FOXO3a levels and BAX levels in lower quality groups, indicating changes in cell cycle progression, oxidative response and apoptosis. Based on these results, the measurement of levels of PI3K-Akt pathway components in FCs from ovarian follicles carrying oocytes with distinct developmental competences is a useful tool to identify putative molecular pathways involved in the acquisition of oocyte competence.

  18. Developmental intervals during the larval and juvenile stages of the Antarctic myctophid fish Electrona antarctica in relation to changes in feeding and swimming functions

    Science.gov (United States)

    Moteki, Masato; Tsujimura, Eri; Hulley, Percy-Alexander

    2017-06-01

    The Antarctic myctophid fish species Electrona antarctica is believed to play a key role in the Southern Ocean food web, but there have been few studies on its early life history. This study examined the developmental changes in the external morphology and osteology of E. antarctica from the early larva to juvenile stages through the transformation phase and inferred changes in its behaviour and feeding mode. Once the larvae reached 12-13 mm body length (BL), they adopted a primordial suction feeding mode along with the acquisition of early swimming capabilities. Thereafter, both swimming and feeding functions were enhanced through fin development and ossification and acquisition of elements of the jaw and suspensorium. These processes indicate that larvae transition from the planktonic to nektonic phase upon reaching 12-13 mm BL when they enhance their both swimming and feeding abilities with growth. Transformation occurred when larvae reached 19-21 mm BL with changes such as discontinuous increases in eye diameter and upper jaw length and the appearance of photophores and dense body pigmentation. Osteological development of swimming- and feeding-related structures were mostly complete after transformation. Rapid changes in external morphology and osteology during the transformation stage are most likely related to ontogenetic vertical migration into deep waters.

  19. Three distinct developmental pathways for adaptive and two IFN-γ-producing γδ T subsets in adult thymus

    DEFF Research Database (Denmark)

    Buus, Terkild Brink; Ødum, Niels; Geisler, Carsten

    2017-01-01

    -producing γδ T cells (γδNKT). Developmental progression towards both IFN-γ-producing subsets can be induced by TCR signalling, and each pathway results in thymic emigration at a different stage. Finally, we show that γδT1 cells are the predominating IFN-γ-producing subset developing in the adult thymus. Thus......, this study maps out three distinct development pathways that result in the programming of γδTn, γδT1 and γδNKT cells.......Murine γδ T cells include subsets that are programmed for distinct effector functions during their development in the thymus. Under pathological conditions, different γδ T cell subsets can be protective or can exacerbate a disease. Here we show that CD117, CD200 and CD371, together with other...

  20. The Diversity of Romantic Pathways during Emerging Adulthood and Their Developmental Antecedents

    Science.gov (United States)

    Shulman, Shmuel; Seiffge-Krenke, Inge; Scharf, Miri; Boiangiu, Shira Bezalel; Tregubenko, Valerya

    2018-01-01

    The present study examined patterns of romantic pathways in 100 Israeli emerging adults (54 males) who were followed from age 22 to 29 years. Analyses of interviews at age 29 yielded four distinctive romantic pathways differing in stability and ability to learn from romantic experiences: "Sporadic," "Lengthy Relationships but…

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

    Science.gov (United States)

    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

  2. Global developmental gene expression and pathway analysis of normal brain development and mouse models of human neuronal migration defects.

    Directory of Open Access Journals (Sweden)

    Tiziano Pramparo

    2011-03-01

    Full Text Available Heterozygous LIS1 mutations are the most common cause of human lissencephaly, a human neuronal migration defect, and DCX mutations are the most common cause of X-linked lissencephaly. LIS1 is part of a protein complex including NDEL1 and 14-3-3ε that regulates dynein motor function and microtubule dynamics, while DCX stabilizes microtubules and cooperates with LIS1 during neuronal migration and neurogenesis. Targeted gene mutations of Lis1, Dcx, Ywhae (coding for 14-3-3ε, and Ndel1 lead to neuronal migration defects in mouse and provide models of human lissencephaly, as well as aid the study of related neuro-developmental diseases. Here we investigated the developing brain of these four mutants and wild-type mice using expression microarrays, bioinformatic analyses, and in vivo/in vitro experiments to address whether mutations in different members of the LIS1 neuronal migration complex lead to similar and/or distinct global gene expression alterations. Consistent with the overall successful development of the mutant brains, unsupervised clustering and co-expression analysis suggested that cell cycle and synaptogenesis genes are similarly expressed and co-regulated in WT and mutant brains in a time-dependent fashion. By contrast, focused co-expression analysis in the Lis1 and Ndel1 mutants uncovered substantial differences in the correlation among pathways. Differential expression analysis revealed that cell cycle, cell adhesion, and cytoskeleton organization pathways are commonly altered in all mutants, while synaptogenesis, cell morphology, and inflammation/immune response are specifically altered in one or more mutants. We found several commonly dysregulated genes located within pathogenic deletion/duplication regions, which represent novel candidates of human mental retardation and neurocognitive disabilities. Our analysis suggests that gene expression and pathway analysis in mouse models of a similar disorder or within a common pathway can

  3. Developmental pathways from maltreatment to risk behavior: Sexual behavior as a catalyst.

    Science.gov (United States)

    Negriff, Sonya

    2018-05-01

    Although delinquency, substance use, and sexual activity are established to be highly intercorrelated, the extant research provides minimal evidence in support of one particular sequence of risk behavior or on the cascade effects from maltreatment. The present study tested a longitudinal model incorporating maltreatment, deviant peers, sexual behavior, delinquency, and substance use to elucidate the sequential pathway(s) from maltreatment to each specific risk behavior throughout adolescence. Data came from a longitudinal study on the effects of maltreatment on adolescent development (N = 454) with four study assessments from early (Time 1 M age = 10.98) to late adolescence (Time 4 M age = 18.22). Results from the cross-lagged model showed a sequence from maltreatment to sexual behavior (Time 1), to delinquency (Time 2), to sexual behavior (Time 3), to substance use and delinquency (Time 4). These findings support sexual behavior as the initial risk behavior that is the catalyst for engagement in more advanced risk behaviors across adolescence.

  4. Developmental pathways from prenatal marijuana exposure to Cannabis Use Disorder in young adulthood.

    Science.gov (United States)

    Sonon, Kristen; Richardson, Gale A; Cornelius, Jack; Kim, Kevin H; Day, Nancy L

    Earlier studies reported an association between prenatal marijuana exposure (PME) and cognitive and behavioral problems in the offspring. A recent publication demonstrated the relation between PME and offspring marijuana use at age 22. There are no reports of the association between PME and Cannabis Use Disorder (CUD) at 22years, the age when use of marijuana and CUD peak. Subjects are from the Maternal Health Practices and Child Development Study, a longitudinal study of PME and other exposures during pregnancy. The cohort of mothers and their offspring has been followed since the fourth prenatal month through 22years of age. A path analysis was conducted on 590 mother-child pairs, representing 77% of the birth cohort, to examine potential pathways from PME to CUD in offspring at 22years of age. There is no direct effect of PME on CUD. There are, however, two indirect pathways from PME to CUD. In the first, the pathway from PME to CUD goes through offspring early age of marijuana onset. In the second, offspring depression at age 10 and early age of marijuana onset predict CUD. Although there is no direct effect of PME on CUD, there are significant indirect pathways from PME to CUD that affect the rate of CUD in the population. Thus, PME, offspring depression, and an early age of marijuana initiation, are significant points for intervention. As marijuana is legalized in more states, the rates of marijuana use will increase significantly, including during pregnancy, and the consequences of the association between PME and CUD will become even more significant from a public health perspective. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Alterations in white matter pathways underlying phonological and morphological processing in Chinese developmental dyslexia

    Directory of Open Access Journals (Sweden)

    Mengmeng Su

    2018-06-01

    Full Text Available Chinese is a logographic language that is different from alphabetic languages in visual and semantic complexity. Thus far, it is still unclear whether Chinese children with dyslexia show similar disruption of white matter pathways as in alphabetic languages. The present study focused on the alteration of white matter pathways in Chinese children with dyslexia. Using diffusion tensor imaging tractography, the bilateral arcuate fasciculus (AF-anterior, AF-posterior and AF-direct segments, inferior fronto-occipital fasciculus (IFOF and inferior longitudinal fasciculus (ILF were delineated in each individual’s native space. Compared with age-matched controls, Chinese children with dyslexia showed reduced fractional anisotropy in the left AF-direct and the left ILF. Further regression analyses revealed a functional dissociation between the left AF-direct and the left ILF. The AF-direct tract integrity was associated with phonological processing skill, an ability important for reading in all writing systems, while the ILF integrity was associated with morphological processing skill, an ability more strongly recruited for Chinese reading. In conclusion, the double disruption locus in Chinese children with dyslexia, and the functional dissociation between dorsal and ventral pathways reflect both universal and specific properties of reading in Chinese.

  6. Defective chromatic and achromatic visual pathways in developmental dyslexia: Cues for an integrated intervention programme.

    Science.gov (United States)

    Bonfiglio, Luca; Bocci, Tommaso; Minichilli, Fabrizio; Crecchi, Alessandra; Barloscio, Davide; Spina, Donata Maria; Rossi, Bruno; Sartucci, Ferdinando

    2017-01-01

    As well as obtaining confirmation of the magnocellular system involvement in developmental dyslexia (DD); the aim was primarily to search for a possible involvement of the parvocellular system; and, furthermore, to complete the assessment of the visual chromatic axis by also analysing the koniocellular system. Visual evoked potentials (VEPs) in response to achromatic stimuli with low luminance contrast and low spatial frequency, and isoluminant red/green and blue/yellow stimuli with high spatial frequency were recorded in 10 dyslexic children and 10 age- and sex-matched, healthy subjects. Dyslexic children showed delayed VEPs to both achromatic stimuli (magnocellular-dorsal stream) and isoluminant red/green and blue/yellow stimuli (parvocellular-ventral and koniocellular streams). To our knowledge, this is the first time that a dysfunction of colour vision has been brought to light in an objective way (i.e., by means of electrophysiological methods) in children with DD. These results give rise to speculation concerning the need for a putative approach for promoting both learning how to read and/or improving existing reading skills of children with or at risk of DD. The working hypothesis would be to combine two integrated interventions in a single programme aimed at fostering the function of both the magnocellular and the parvocellular streams.

  7. Specific developmental pathways underlie host specificity in the parasitic plant Orobanche

    Science.gov (United States)

    Hiscock, Simon

    2010-01-01

    Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants. PMID:20081361

  8. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

    Science.gov (United States)

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-01-01

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

  9. Developmental pathways of change in fitness and motor competence are related to overweight and obesity status at the end of primary school.

    Science.gov (United States)

    Rodrigues, Luis P; Stodden, David F; Lopes, Vítor P

    2016-01-01

    To test how different developmental pathways of health-related physical fitness and motor competence tests relate to weight status (overweight and obesity) at the end of primary school. Longitudinal study on growth, health-related physical fitness, and motor competence of 472 primary school children assessed yearly throughout 1st to 4th grade, with an average age of 6.3±0.7 years of age at 1st grade. Children's pathways of change on each of the fitness and motor competence tests were determined along the four years of the study. Participants were divided into three groups according to their rate of change in each test over time: Low Rate of Change, Average Rate of Change, and High Rate of Change. A logistic regression was used to predict the odds ratio of becoming overweight or obese, depending on the developmental pathway of change in fitness and motor competence across childhood. Children with a low or average rate of change in their developmental pathways of fitness and motor competence were several times more prone to become overweight or obese at the end of primary school (OR 2.0 to 6.3), independent of sex and body mass index at baseline. Specifically, a negative developmental pathway (Low Rate of Change) in cardiorespiratory fitness demonstrated over a six-fold elevated risk of being overweight or obese, compared to peers with a positive pathway. Not all children improve their motor competence and fitness levels over time and many actually regress over time. Developing positive fitness and motor competence pathways during childhood protects from obesity and overweight. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  10. Identification of microRNAs regulating the developmental pathways of bone marrow derived mast cells.

    Directory of Open Access Journals (Sweden)

    Yang Xiang

    Full Text Available MicroRNAs (miRNAs play important roles in leukocyte differentiation, although those utilised for specific programs and key functions remain incompletely characterised. As a global approach to gain insights into the potential regulatory role of miRNA in mast cell differentiation we characterised expression in BM cultures from the initiation of differentiation. In cultures enriched in differentiating mast cells we characterised miRNA expression and identified miRNA targeting the mRNA of putative factors involved in differentiation pathways and cellular identity. Detailed pathway analysis identified a unique miRNA network that is intimately linked to the mast cell differentiation program.We identified 86 unique miRNAs with expression patterns that were up- or down- regulated at 5-fold or more during bone marrow derived mast cells (BMMC development. By employing TargetScan and MeSH databases, we identified 524 transcripts involved in 30 canonical pathways as potentially regulated by these specific 86 miRNAs. Furthermore, by applying miRanda and IPA analyses, we predict that 7 specific miRNAs of this group are directly associated with the expression of c-Kit and FcεRIα and likewise, that 18 miRNAs promote expression of Mitf, GATA1 and c/EBPα three core transcription factors that direct mast cell differentiation. Furthermore, we have identified 11 miRNAs that may regulate the expression of STATs-3, -5a/b, GATA2 and GATA3 during differentiation, along with 13 miRNAs that target transcripts encoding Ndst2, mMCP4 and mMCP6 and thus may regulate biosynthesis of mast cell secretory mediators.This investigation characterises changes in miRNA expression in whole BM cultures during the differentiation of mast cells and predicts functional links between miRNAs and their target mRNAs for the regulation of development. This information provides an important resource for further investigations of the contributions of miRNAs to mast cell differentiation and

  11. Developmentally programmed DNA deletion in Tetrahymena thermophila by a transposition-like reaction pathway.

    Science.gov (United States)

    Saveliev, S V; Cox, M M

    1996-01-01

    We provide a molecular description of key intermediates in the deletion of two internal eliminated sequences (IES elements), the M and R regions, during macronuclear development in Tetrahymena thermophila. Using a variety of PCR-based methods in vivo, double-strand breaks are detected that are generated by hydrolytic cleavage and correspond closely to the observed chromosomal junctions left behind in the macronuclei. The breaks exhibit a temporal and structural relationship to the deletion reaction that provides strong evidence that they are intermediates in the deletion pathway. Breaks in the individual strands are staggered by 4 bp, producing a four nucleotide 5' extension. Evidence is presented that breaks do not occur simultaneously at both ends. The results are most consistent with a deletion mechanism featuring initiation by double-strand cleavage at one end of the deleted element, followed by transesterification to generate the macronuclear junction on one DNA strand. An adenosine residue is found at all the nucleophilic 3' ends used in the postulated transesterification step. Evidence for the transesterification step is provided by detection of a 3' hydroxyl that would be liberated by such a step at a deletion boundary where no other DNA strand ends are detected. Images PMID:8654384

  12. Obestatin enhances in vitro generation of pancreatic islets through regulation of developmental pathways.

    Directory of Open Access Journals (Sweden)

    Alessandra Baragli

    Full Text Available Availability of large amounts of in vitro generated β-cells may support replacement therapy in diabetes. However, methods to obtain β-cells from stem/progenitor cells are limited by inefficient endocrine differentiation. We have recently shown that the ghrelin gene product obestatin displays beneficial effects on pancreatic β-cell survival and function. Obestatin prevents β-cell apoptosis, preserves β-cell mass and stimulates insulin secretion in vitro and in vivo, in both normal and diabetic conditions. In the present study, we investigated whether obestatin may promote in vitro β-cell generation from mouse pancreatic islet-derived precursor cells. Treatment of cultured islets of Langerhans with obestatin (i enriched cells expressing the mesenchymal/neuronal marker nestin, which is associated with pancreatic precursors; (ii increased cell survival and reduced apoptosis during precursor selection; (iii promoted the generation of islet-like cell clusters (ICCs with increased insulin gene expression and C-peptide secretion. Furthermore, obestatin modulated the expression of fibroblast growth factor receptors (FGFRs, Notch receptors and neurogenin 3 (Ngn3 during islet-derived precursor cell selection and endocrine differentiation. These results indicate that obestatin improves the generation of functional β-cells/ICCs in vitro, suggesting implications for cell-based replacement therapy in diabetes. Moreover, obestatin may play a role in regulating pathways involved in pancreas development and regeneration.

  13. Proteomic analysis of Oesophagostomum dentatum (Nematoda during larval transition, and the effects of hydrolase inhibitors on development.

    Directory of Open Access Journals (Sweden)

    Martina Ondrovics

    Full Text Available In this study, in vitro drug testing was combined with proteomic and bioinformatic analyses to identify and characterize proteins involved in larval development of Oesophagostomum dentatum, an economically important parasitic nematode. Four hydrolase inhibitors ο-phenanthroline, sodium fluoride, iodoacetamide and 1,2-epoxy-3-(pnitrophenoxy-propane (EPNP significantly inhibited (≥90% larval development. Comparison of the proteomic profiles of the development-inhibited larvae with those of uninhibited control larvae using two-dimensional gel electrophoresis, and subsequent MALDI-TOF mass spectrometric analysis identified a down-regulation of 12 proteins inferred to be involved in various larval developmental processes, including post-embryonic development and growth. Furthermore, three proteins (i.e. intermediate filament protein B, tropomyosin and peptidyl-prolyl cis-trans isomerase inferred to be involved in the moulting process were down-regulated in moulting- and development-inhibited O. dentatum larvae. This first proteomic map of O. dentatum larvae provides insights in the protein profile of larval development in this parasitic nematode, and significantly improves our understanding of the fundamental biology of its development. The results and the approach used might assist in developing new interventions against parasitic nematodes by blocking or disrupting their key biological pathways.

  14. Molecular dissection of prethymic progenitor entry into the T lymphocyte developmental pathway

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Elizabeth-sharon [Los Alamos National Laboratory

    2008-01-01

    Notch signaling activates T lineage differentiation from hemopoietic progenitors, but relatively few regulators that initiate this program have been identified, e.g., GATA3 and T cell factor-I (TCF-1) (gene name Tcli). To identify additional regulators of T cell specification, a cDNA libnlrY from mouse Pro-T cells was screened for genes that are specifically up-regulated in intrathymic T cell precursors as compared with myeloid progenitors. Over 90 genes of interest were identified, and 35 of 44 tested were confirmed to be more highly expressed in T lineage precursors relative to precursors of B and/or myeloid lineage. To a remarkable extent, however, expression of these T lineage-enriched genes, including zinc finger transcription factor, helicase, and signaling adaptor genes, was also shared by stem cells (Lin{sup -}Sca-1{sup +}Kit{sup +}CD27{sup -}) and multipotent progenitors (Lin{sup -}Sca-l{sup +}Kit{sup +}CD27{sup +}), although down-regulated in other lineages. Thus, a major fraction of these early T lineage genes are a regulatory legacy from stem cells. The few genes sharply up-regulated between multipotent progenitors and Pro-T cell stages included those encoding transcription factors Bclllb, TCF-I (Tcli), and HEBalt, Notch target Deltexl, Deltex3L, Fkbp5, Eval, and Tmem13l. Like GATA3 and Deltexl, Bclllb, Fkbp5, and Eval were dependent on Notch/Delta signaling for induction in fetal liver precursors, but only BcIlI band HEBalt were up-regulated between the first two stages of intrathymic T cell development (double negative I and double negative 2) corresponding to T lineage specification. Bclllb was uniquely T lineage restricted and induced by NotchlDelta signaling specifically upon entry into the T lineage differentiation pathway.

  15. Quantitative proteomics links metabolic pathways to specific developmental stages of the plant-pathogenic oomycete Phytophthora capsici.

    Science.gov (United States)

    Pang, Zhili; Srivastava, Vaibhav; Liu, Xili; Bulone, Vincent

    2017-04-01

    The oomycete Phytophthora capsici is a plant pathogen responsible for important losses to vegetable production worldwide. Its asexual reproduction plays an important role in the rapid propagation and spread of the disease in the field. A global proteomics study was conducted to compare two key asexual life stages of P. capsici, i.e. the mycelium and cysts, to identify stage-specific biochemical processes. A total of 1200 proteins was identified using qualitative and quantitative proteomics. The transcript abundance of some of the enriched proteins was also analysed by quantitative real-time polymerase chain reaction. Seventy-three proteins exhibited different levels of abundance between the mycelium and cysts. The proteins enriched in the mycelium are mainly associated with glycolysis, the tricarboxylic acid (or citric acid) cycle and the pentose phosphate pathway, providing the energy required for the biosynthesis of cellular building blocks and hyphal growth. In contrast, the proteins that are predominant in cysts are essentially involved in fatty acid degradation, suggesting that the early infection stage of the pathogen relies primarily on fatty acid degradation for energy production. The data provide a better understanding of P. capsici biology and suggest potential metabolic targets at the two different developmental stages for disease control. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  16. Developmental pathway from leaves to galls induced by a sap-feeding insect on Schinus polygamus (Cav.) Cabrera (Anacardiaceae).

    Science.gov (United States)

    Dias, Graciela G; Ferreira, Bruno G; Moreira, Gilson R P; Isaias, Rosy M S

    2013-03-01

    Galling sap-feeding insects are presumed to cause only minor changes in host plant tissues, because they usually do not require development of nutritive tissues for their own use. This premise was examined through comparison of the histometry, cytometry and anatomical development of non-galled leaves and galls of Calophya duvauae (Scott) (Hemiptera: Calophyidae) on Schinus polygamus (Cav.) Cabrera (Anacardiaceae). Cell fates changed from non-galled leaves to galls during the course of tissue differentiation. C. duvauae caused changes in dermal, ground, and vascular systems of the leaves of S. polygamus. Its feeding activity induced the homogenization of the parenchyma, and the neoformation of vascular bundles and trichomes. The histometric and cytometric data revealed compensatory effects of hyperplasia and cell hypertrophy in the epidermis, with hyperplasia predominating in the adaxial epidermis. There was a balance between these processes in the other tissues. Thus, we found major differences between the developmental pathways of non-galled leaves and galls. These changes were associated with phenotypic alterations related to shelter and appropriate microenvironmental conditions for the gall inducer. The nondifferentiation of a typical nutritive tissue in this case was compared to other non-phylogenetically related arthropod gall systems, and is suggested to result from convergence associated with the piercing feeding apparatus of the corresponding gall-inducer.

  17. Analysis of synaptic growth and function in Drosophila with an extended larval stage.

    Science.gov (United States)

    Miller, Daniel L; Ballard, Shannon L; Ganetzky, Barry

    2012-10-03

    The Drosophila larval neuromuscular junction (NMJ) is a powerful system for the genetic and molecular analysis of neuronal excitability, synaptic transmission, and synaptic development. However, its use for studying age-dependent processes, such as maintenance of neuronal viability and synaptic stability, are temporally limited by the onset of pupariation and metamorphosis. Here we characterize larval NMJ growth, growth regulation, structure, and function in a developmental variant with an extended third instar (ETI). RNAi-knockdown of the prothoracicotropic hormone receptor, torso, in the ring gland of developing larvae leaves the timing of first and second instar molts largely unchanged, but triples duration of the third instar from 3 to 9.5 d (McBrayer et al., 2007; Rewitz et al., 2009). During this ETI period, NMJs undergo additional growth (adding >50 boutons/NMJ), and this growth remains under the control of the canonical regulators Highwire and the TGFβ/BMP pathway. NMJ growth during the ETI period occurs via addition of new branches, satellite boutons, and interstitial boutons, and continues even after muscle growth levels off. Throughout the ETI, organization of synapses and active zones remains normal, and synaptic transmission is unchanged. These results establish the ETI larval system as a viable model for studying motor neuron diseases and for investigating time-dependent effects of perturbations that impair mechanisms of neuroprotection, synaptic maintenance, and response to neural injury.

  18. Adolescent Conflict as a Developmental Process in the Prospective Pathway from Exposure to Interparental Violence to Dating Violence

    Science.gov (United States)

    Narayan, Angela J.; Englund, Michelle M.; Carlson, Elizabeth A.; Egeland, Byron

    2013-01-01

    Within a developmental psychopathology framework, the current study examined adolescent conflict (age 16) with families, best friends, and dating partners as mediators in the prospective pathway from exposure to interparental violence (EIPV) in early childhood (0–64 months) to dating violence perpetration and victimization in early adulthood (age 23). Adolescent conflict was predicted to partially mediate EIPV and dating violence with significant direct paths from EIPV to dating violence, given the extant literature on the salience of early childhood EIPV for later maladjustment. Participants (N = 182; 99 males, 83 females; 67% Caucasian, 11% African-American, 18% other, 4% unreported) were drawn from a larger prospective study of high-risk mothers (aged 12–34 years) that followed their children from birth through adulthood. EIPV and adolescent conflict were rated from interviews with mothers and participants, and dating violence (physical perpetration and victimization) was assessed with the Conflict Tactics Scale. Path analyses showed that EIPV in early childhood (a) directly predicted dating violence perpetration in early adulthood and (b) predicted conflict with best friends, which in turn predicted dating violence perpetration. Although mediation of best friend conflict was not evident, indirect effects of EIPV to dating violence were found through externalizing behaviors in adolescence and life stress in early adulthood. Findings highlight that conflict with best friends is affected by EIPV and predicts dating violence, suggesting that it may be a promising target for relationship-based interventions for youth with EIPV histories. Furthermore, deleterious early experiences and contemporaneous risk factors are salient predictors of dating violence. PMID:23979004

  19. Comparative Developmental Toxicity of Flavonoids Using an Integrative Zebrafish System.

    Science.gov (United States)

    Bugel, Sean M; Bonventre, Josephine A; Tanguay, Robert L

    2016-11-01

    Flavonoids are a large, structurally diverse class of bioactive naturally occurring chemicals commonly detected in breast milk, soy based infant formulas, amniotic fluid, and fetal cord blood. The potential for pervasive early life stage exposures raises concerns for perturbation of embryogenesis, though developmental toxicity and bioactivity information is limited for many flavonoids. Therefore, we evaluated a suite of 24 flavonoid and flavonoid-like chemicals using a zebrafish embryo-larval toxicity bioassay-an alternative model for investigating developmental toxicity of environmentally relevant chemicals. Embryos were exposed to 1-50 µM of each chemical from 6 to 120 h postfertilization (hpf), and assessed for 26 adverse developmental endpoints at 24, 72, and 120 hpf. Behavioral changes were evaluated in morphologically normal animals at 24 and 72 hpf, at 120 hpf using a larval photomotor response (LPR) assay. Gene expression was comparatively evaluated for all compounds for effects on biomarker transcripts indicative of AHR (cyp1a) and ER (cyp19a1b, esr1, lhb, vtg) pathway bioactivity. Overall, 15 of 24 flavonoids elicited adverse effects on one or more of the developmental or behavioral endpoints. Hierarchical clustering and principle component analyses compared toxicity profiles and identified 3 distinct groups of bioactive flavonoids. Despite robust induction of multiple estrogen-responsive biomarkers, co-exposure with ER and GPER antagonists did not ameliorate toxicity, suggesting ER-independence and alternative modes of action. Taken together, these studies demonstrate that development is sensitive to perturbation by bioactive flavonoids in zebrafish that are not related to traditional estrogen receptor mode of action pathways. This integrative zebrafish platform provides a useful framework for evaluating flavonoid developmental toxicity and hazard prioritization. © The Author 2016. Published by Oxford University Press on behalf of the Society of

  20. Expression profiling of prospero in the Drosophila larval chemosensory organ: Between growth and outgrowth

    Directory of Open Access Journals (Sweden)

    Raharijaona Mahatsangy

    2010-01-01

    Full Text Available Abstract Background The antenno-maxilary complex (AMC forms the chemosensory system of the Drosophila larva and is involved in gustatory and olfactory perception. We have previously shown that a mutant allele of the homeodomain transcription factor Prospero (prosVoila1, V1, presents several developmental defects including abnormal growth and altered taste responses. In addition, many neural tracts connecting the AMC to the central nervous system (CNS were affected. Our earlier reports on larval AMC did not argue in favour of a role of pros in cell fate decision, but strongly suggested that pros could be involved in the control of other aspect of neuronal development. In order to identify these functions, we used microarray analysis of larval AMC and CNS tissue isolated from the wild type, and three other previously characterised prospero alleles, including the V1 mutant, considered as a null allele for the AMC. Results A total of 17 samples were first analysed with hierarchical clustering. To determine those genes affected by loss of pros function, we calculated a discriminating score reflecting the differential expression between V1 mutant and other pros alleles. We identified a total of 64 genes in the AMC. Additional manual annotation using all the computed information on the attributed role of these genes in the Drosophila larvae nervous system, enabled us to identify one functional category of potential Prospero target genes known to be involved in neurite outgrowth, synaptic transmission and more specifically in neuronal connectivity remodelling. The second category of genes found to be differentially expressed between the null mutant AMC and the other alleles concerned the development of the sensory organs and more particularly the larval olfactory system. Surprisingly, a third category emerged from our analyses and suggests an association of pros with the genes that regulate autophagy, growth and insulin pathways. Interestingly, EGFR and

  1. Effect of massing on larval growth rate.

    Science.gov (United States)

    Johnson, Aidan P; Wallman, James F

    2014-08-01

    Estimation of minimum postmortem interval commonly relies on predicting the age of blowfly larvae based on their size and an estimate of the temperatures to which they have been exposed throughout their development. The majority of larval growth rate data have been developed using small larval masses in order to avoid excess heat generation. The current study collected growth rate data for larvae at different mass volumes, and assessed the temperature production of these masses, for two forensically important blow fly species, Chrysomya rufifacies and Calliphora vicina. The growth rate of larvae in a small mass, exposed to the higher temperatures equivalent to those experienced by large masses, was also assessed to determine if observed differences were due to the known temperature effects of maggot masses. The results showed that temperature production increased with increasing mass volume, with temperature increases of 11 °C observed in the large Ch. rufifacies masses and increases of 5 °C in the large C. vicina masses. Similarly, the growth rate of the larvae was affected by mass size. The larvae from small masses grown at the higher temperatures experienced by large masses displayed an initial delay in growth, but then grew at a similar rate to those larvae at a constant 23 °C. Since these larvae from masses of equivalent sizes displayed similar patterns of growth rate, despite differing temperatures, and these growth rates differed from larger masses exposed to the same temperatures, it can be concluded that larval growth rate within a mass may be affected by additional factors other than temperature. Overall, this study highlights the importance of understanding the role of massing in larval development and provides initial developmental data for mass sizes of two forensically important blowfly species commonly encountered in Australian forensic casework. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Interdyad Differences in Early Mother-Infant Face-to-Face Communication: Real-Time Dynamics and Developmental Pathways

    Science.gov (United States)

    Lavelli, Manuela; Fogel, Alan

    2013-01-01

    A microgenetic research design with a multiple case study method and a combination of quantitative and qualitative analyses was used to investigate interdyad differences in real-time dynamics and developmental change processes in mother-infant face-to-face communication over the first 3 months of life. Weekly observations of 24 mother-infant dyads…

  3. GC-MS Metabolomic Analysis to Reveal the Metabolites and Biological Pathways Involved in the Developmental Stages and Tissue Response of Panax ginseng

    Directory of Open Access Journals (Sweden)

    Jia Liu

    2017-03-01

    Full Text Available Ginsenosides, the major compounds present in ginseng, are known to have numerous physiological and pharmacological effects. The physiological processes, enzymes and genes involved in ginsenoside synthesis in P. ginseng have been well characterized. However, relatively little information is known about the dynamic metabolic changes that occur during ginsenoside accumulation in ginseng. To explore this topic, we isolated metabolites from different tissues at different growth stages, and identified and characterized them by using gas chromatography coupled with mass spectrometry (GC-MS. The results showed that a total of 30, 16, 20, 36 and 31 metabolites were identified and involved in different developmental stages in leaf, stem, petiole, lateral root and main root, respectively. To investigate the contribution of tissue to the biosynthesis of ginsenosides, we examined the metabolic changes of leaf, stem, petiole, lateral root and main root during five development stages: 1-, 2-, 3-, 4- and 5-years. The score plots of partial least squares-discriminate analysis (PLS-DA showed clear discrimination between growth stages and tissue samples. Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analysis in the same tissue at different growth stages indicated profound biochemical changes in several pathways, including carbohydrate metabolism and pentose phosphate metabolism, in addition, the tissues displayed significant variations in amino acid metabolism, sugar metabolism and energy metabolism. These results should facilitate further dissection of the metabolic flux regulation of ginsenoside accumulation in different developmental stages or different tissues of ginseng.

  4. BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae-Sik; Han, Jeonghoon; Won, Eun-Ji; Kim, Duck-Hyun; Jeong, Chang-Bum [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Hwang, Un-Ki [Marine Ecological Risk Assessment Center, West Sea Fisheries Research Institute, National Fisheries Research & Development Institute, Incheon 46083 (Korea, Republic of); Zhou, Bingsheng [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Choe, Joonho [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419 (Korea, Republic of)

    2016-08-15

    Highlights: • The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47. • Expression profiles of nearly all NR genes were the highest at naupliar stages 5–6. • USP, HR96, and FTZ-F1 genes showed significant sex differences (P < 0.05) over different developmental stages. • NR gene expression patterns showed significant decreases (P<0.05) in response to BDE-47. • BDE-47 leads to molting and metamorphosis retardation and suppresses transcription of NR genes. - Abstract: 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g. developmental retardation) in ecdysozoa, the effects of BDE-47 on transcription of ecdysteroid signaling pathway-involved-nuclear receptor (NR) genes and metamorphosis-related genes have not been examined in copepods. To examine the deleterious effect of BDE-47 on copepod molting and metamorphosis, BDE-47 was exposed to the harpacticoid copepod Tigriopus japonicus, followed by monitoring developmental retardation and transcriptional alteration of NR genes. The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47 and the agricultural insecticide gamma-hexachlorocyclohexane. Conversely, the ecdysteroid agonist ponasterone A (PoA) led to decreased molting and metamorphosis time (P < 0.05) from the nauplius stage to the adult stage. In particular, expression profiles of all NR genes were the highest at naupliar stages 5–6 except for SVP, FTZ-F1, and HR96 genes. Nuclear receptor USP, HR96, and FTZ-F1 genes also showed significant sex differences (P < 0.05) in gene expression levels over different developmental stages, indicating that these genes may be involved in vitellogenesis. NR gene expression patterns showed significant decreases (P < 0.05) in response to BDE-47 exposure, implying that molting and metamorphosis retardation is likely associated with NR gene expression. In summary, BDE-47

  5. BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus

    International Nuclear Information System (INIS)

    Hwang, Dae-Sik; Han, Jeonghoon; Won, Eun-Ji; Kim, Duck-Hyun; Jeong, Chang-Bum; Hwang, Un-Ki; Zhou, Bingsheng; Choe, Joonho; Lee, Jae-Seong

    2016-01-01

    Highlights: • The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47. • Expression profiles of nearly all NR genes were the highest at naupliar stages 5–6. • USP, HR96, and FTZ-F1 genes showed significant sex differences (P < 0.05) over different developmental stages. • NR gene expression patterns showed significant decreases (P<0.05) in response to BDE-47. • BDE-47 leads to molting and metamorphosis retardation and suppresses transcription of NR genes. - Abstract: 2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g. developmental retardation) in ecdysozoa, the effects of BDE-47 on transcription of ecdysteroid signaling pathway-involved-nuclear receptor (NR) genes and metamorphosis-related genes have not been examined in copepods. To examine the deleterious effect of BDE-47 on copepod molting and metamorphosis, BDE-47 was exposed to the harpacticoid copepod Tigriopus japonicus, followed by monitoring developmental retardation and transcriptional alteration of NR genes. The developmental rate was significantly inhibited (P < 0.05) in response to BDE-47 and the agricultural insecticide gamma-hexachlorocyclohexane. Conversely, the ecdysteroid agonist ponasterone A (PoA) led to decreased molting and metamorphosis time (P < 0.05) from the nauplius stage to the adult stage. In particular, expression profiles of all NR genes were the highest at naupliar stages 5–6 except for SVP, FTZ-F1, and HR96 genes. Nuclear receptor USP, HR96, and FTZ-F1 genes also showed significant sex differences (P < 0.05) in gene expression levels over different developmental stages, indicating that these genes may be involved in vitellogenesis. NR gene expression patterns showed significant decreases (P < 0.05) in response to BDE-47 exposure, implying that molting and metamorphosis retardation is likely associated with NR gene expression. In summary, BDE-47

  6. BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus.

    Science.gov (United States)

    Hwang, Dae-Sik; Han, Jeonghoon; Won, Eun-Ji; Kim, Duck-Hyun; Jeong, Chang-Bum; Hwang, Un-Ki; Zhou, Bingsheng; Choe, Joonho; Lee, Jae-Seong

    2016-08-01

    2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g. developmental retardation) in ecdysozoa, the effects of BDE-47 on transcription of ecdysteroid signaling pathway-involved-nuclear receptor (NR) genes and metamorphosis-related genes have not been examined in copepods. To examine the deleterious effect of BDE-47 on copepod molting and metamorphosis, BDE-47 was exposed to the harpacticoid copepod Tigriopus japonicus, followed by monitoring developmental retardation and transcriptional alteration of NR genes. The developmental rate was significantly inhibited (P<0.05) in response to BDE-47 and the agricultural insecticide gamma-hexachlorocyclohexane. Conversely, the ecdysteroid agonist ponasterone A (PoA) led to decreased molting and metamorphosis time (P<0.05) from the nauplius stage to the adult stage. In particular, expression profiles of all NR genes were the highest at naupliar stages 5-6 except for SVP, FTZ-F1, and HR96 genes. Nuclear receptor USP, HR96, and FTZ-F1 genes also showed significant sex differences (P<0.05) in gene expression levels over different developmental stages, indicating that these genes may be involved in vitellogenesis. NR gene expression patterns showed significant decreases (P<0.05) in response to BDE-47 exposure, implying that molting and metamorphosis retardation is likely associated with NR gene expression. In summary, BDE-47 leads to molting and metamorphosis retardation and suppresses transcription of NR genes. This information will be helpful in understanding the molting and metamorphosis delay mechanism in response to BDE-47 exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Attention-Deficit/Hyperactivity Disorder and Risk of Substance Use Disorder: Developmental Considerations, Potential Pathways, and Opportunities for Research

    Science.gov (United States)

    Molina, Brooke S.G.; Pelham, William E.

    2014-01-01

    Many opportunities to explain ADHD-related risk of substance use/disorder (SUD) remain available for study. We detail these opportunities by considering characteristics of children with ADHD and factors affecting their outcomes side-by-side with overlapping variables in the developmental literature on SUD etiology. Although serious conduct problems are a known contributor to ADHD-related risk of SUD, few studies have considered their emergence developmentally and in relation to other candidate mediators and moderators that could also explain risk and be intervention targets. Common ADHD-related impairments, such as school difficulties, are in need of research. Heterogeneous social impairments have the potential for predisposing, and buffering, influences. Research on neurocognitive domains should move beyond standard executive function batteries to measure deficits in the interface between cognitive control, reward, and motivation. Ultimately, maximizing prediction will depend, as it has in the SUD literature, on simultaneous consideration of multiple risk factors. PMID:24437435

  8. Exposure to Parents' Negative Emotions as a Developmental Pathway to the Family Aggregation of Depression and Anxiety in the First Year of Life.

    Science.gov (United States)

    Aktar, Evin; Bögels, Susan M

    2017-12-01

    Depression and anxiety load in families. In the present study, we focus on exposure to parental negative emotions in first postnatal year as a developmental pathway to early parent-to-child transmission of depression and anxiety. We provide an overview of the little research available on the links between infants' exposure to negative emotion and infants' emotional development in this developmentally sensitive period, and highlight priorities for future research. To address continuity between normative and maladaptive development, we discuss exposure to parental negative emotions in infants of parents with as well as without depression and/or anxiety diagnoses. We focus on infants' emotional expressions in everyday parent-infant interactions, and on infants' attention to negative facial expressions as early indices of emotional development. Available evidence suggests that infants' emotional expressions echo parents' expressions and reactions in everyday interactions. In turn, infants exposed more to negative emotions from the parent seem to attend less to negative emotions in others' facial expressions. The links between exposure to parental negative emotion and development hold similarly in infants of parents with and without depression and/or anxiety diagnoses. Given its potential links to infants' emotional development, and to later psychological outcomes in children of parents with depression and anxiety, we conclude that early exposure to parental negative emotions is an important developmental mechanism that awaits further research. Longitudinal designs that incorporate the study of early exposure to parents' negative emotion, socio-emotional development in infancy, and later psychological functioning while considering other genetic and biological vulnerabilities should be prioritized in future research.

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

    Science.gov (United States)

    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. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  10. Developmental fluoride exposure influenced rat's splenic development and cell cycle via disruption of the ERK signal pathway.

    Science.gov (United States)

    Ma, Yanqin; Zhang, Kankan; Ren, Fengjun; Wang, Jundong

    2017-11-01

    Excessive fluoride exposure has been reported to cause damage to spleen. Neonatal period is characterized by rapid proliferation and differentiation of lymphocyte in the spleen. Children may be more sensitive to the toxicity of fluoride compared to the adults. The aim of this study was to investigate the effects of postnatal exposure (from neonatal period to early adulthood) to fluoride on the development of spleen on a regular basis and the underlying signal pathway. Results showed a marked decrease in spleen weight index and altered morphology in the spleen of fluoride-treated group on PND-84, which reflected fluoride inhibition of the development of spleen. Fluoride exposure induced cell cycle arrest of splenocytes and decreased the mRNA expression of IL-2, which indicated compromised baseline lymphocyte proliferation in the spleen. Time course research from 3-wk-of-age until 12-wk-of-age showed an adverse and cumulative impact of fluoride on the development of spleen. In view of the key role of MAPK/ERK pathway in lymphocyte development, Raf-1/MEK-1/ERK-2/c-fos mRNA expression and ERK/p-ERK protein expression were detected. Results showed despite a transitory increase in mRNA expression from PND-42 to PND-63 in fluoride-treated group, the expression of these genes on PND-84 decreased significantly compared with PND-42 or PND-63. NaF significantly inhibited the phosphorylation of ERK protein on PND-84. Taken together, these results emphasized the vital role of ERK pathway in the interfered development of spleen induced by a high dose of fluoride exposure in rats. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Developmental programming: effect of prenatal steroid excess on intraovarian components of insulin signaling pathway and related proteins in sheep.

    Science.gov (United States)

    Ortega, Hugo H; Rey, Florencia; Velazquez, Melisa M L; Padmanabhan, Vasantha

    2010-06-01

    Prenatal testosterone (T) excess increases ovarian follicular recruitment, follicular persistence, insulin resistance, and compensatory hyperinsulinemia. Considering the importance of insulin in ovarian physiology, in this study, using prenatal T- and dihydrotestosterone (DHT, a nonaromatizable androgen)-treated female sheep, we tested the hypothesis that prenatal androgen excess alters the intraovarian insulin signaling cascade and metabolic mediators that have an impact on insulin signaling. Changes in ovarian insulin receptor (INSRB), insulin receptor substrate 1 (IRS1), mammalian target of rapamycin (MTOR), phosphatidylinositol 3-kinase (PIK3), peroxisome proliferator-activated receptor-gamma (PPARG), and adiponectin proteins were determined at fetal (Days 90 and 140), postpubertal (10 mo), and adult (21 mo) ages by immunohistochemistry. Results indicated that these proteins were expressed in granulosa, theca, and stromal compartments, with INSRB, IRS1, PPARG, and adiponectin increasing in parallel with advanced follicular differentiation. Importantly, prenatal T excess induced age-specific changes in PPARG and adiponectin expression, with increased PPARG expression evident during fetal life and decreased antral follicular adiponectin expression during adult life. Comparison of developmental changes in prenatal T and DHT-treated females found that the effects on PPARG were programmed by androgenic actions of T, whereas the effects on adiponectin were likely by its estrogenic action. These results suggest a role for PPARG in the programming of ovarian disruptions by prenatal T excess, including a decrease in antral follicular adiponectin expression and a contributory role for adiponectin in follicular persistence and ovulatory failure.

  12. MEF2C Haploinsufficiency features consistent hyperkinesis, variable epilepsy, and has a role in dorsal and ventral neuronal developmental pathways

    Science.gov (United States)

    Paciorkowski, Alex R.; Traylor, Ryan N.; Rosenfeld, Jill A.; Hoover, Jacqueline M.; Harris, Catharine J.; Winter, Susan; Lacassie, Yves; Bialer, Martin; Lamb, Allen N.; Schultz, Roger A.; Berry-Kravis, Elizabeth; Porter, Brenda E.; Falk, Marni; Venkat, Anu; Vanzo, Rena J.; Cohen, Julie S.; Fatemi, Ali; Dobyns, William B.; Shaffer, Lisa G.; Ballif, Blake C.; Marsh, Eric D.

    2013-01-01

    MEF2C haploinsufficiency syndrome is an emerging neurodevelopmental disorder associated with intellectual disability, autistic features, epilepsy, and abnormal movements. We report 16 new patients with MEF2C haploinsufficiency, including the oldest reported patient with MEF2C deletion at 5q14.3. We detail the neurobehavioral phenotype, epilepsy, and abnormal movements, and compare our subjects with those previously reported in the literature. We also investigate Mef2c expression in the developing mouse forebrain. A spectrum of neurofunctional deficits emerges, with hyperkinesis a consistent finding. Epilepsy varied from absent to severe, and included intractable myoclonic seizures and infantile spasms. Subjects with partial MEF2C deletion were statistically less likely to have epilepsy. Finally, we confirm that Mef2c is present both in dorsal primary neuroblasts and ventral gamma-aminobutyric acid(GABA)ergic interneurons in the forebrain of the developing mouse. Given interactions with several key neurodevelopmental genes such as ARX, FMR1, MECP2, and TBR1, it appears that MEF2C plays a role in several developmental stages of both dorsal and ventral neuronal cell types. PMID:23389741

  13. Transcriptome analysis elucidates key developmental components of bryozoan lophophore development

    KAUST Repository

    Wong, Yue Him

    2014-10-10

    The most recent phylogenomic study suggested that Bryozoa (Ectoprocta), Brachiopoda, and Phoronida are monophyletic, implying that the lophophore of bryozoans, phoronids and brachiopods is a synapomorphy. Understanding the molecular mechanisms of the lophophore development of the Lophophorata clade can therefore provide us a new insight into the formation of the diverse morphological traits in metazoans. In the present study, we profiled the transcriptome of the Bryozoan (Ectoproct) Bugula neritina during the swimming larval stage (SW) and the early (4 h) and late (24 h) metamorphic stages using the Illumina HiSeq2000 platform. Various genes that function in development, the immune response and neurogenesis showed differential expression levels during metamorphosis. In situ hybridization of 23 genes that participate in the Wnt, BMP, Notch, and Hedgehog signaling pathways revealed their regulatory roles in the development of the lophophore and the ancestrula digestive tract. Our findings support the hypothesis that developmental precursors of the lophophore and the ancestrula digestive tract are pre-patterned by the differential expression of key developmental genes according to their fate. This study provides a foundation to better understand the developmental divergence and/or convergence among developmental precursors of the lophophore of bryozoans, branchiopods and phoronids.

  14. Activation of multiple signaling pathways causes developmental defects in mice with a Noonan syndrome–associated Sos1 mutation

    Science.gov (United States)

    Chen, Peng-Chieh; Wakimoto, Hiroko; Conner, David; Araki, Toshiyuki; Yuan, Tao; Roberts, Amy; Seidman, Christine E.; Bronson, Roderick; Neel, Benjamin G.; Seidman, Jonathan G.; Kucherlapati, Raju

    2010-01-01

    Noonan syndrome (NS) is an autosomal dominant genetic disorder characterized by short stature, unique facial features, and congenital heart disease. About 10%–15% of individuals with NS have mutations in son of sevenless 1 (SOS1), which encodes a RAS and RAC guanine nucleotide exchange factor (GEF). To understand the role of SOS1 in the pathogenesis of NS, we generated mice with the NS-associated Sos1E846K gain-of-function mutation. Both heterozygous and homozygous mutant mice showed many NS-associated phenotypes, including growth delay, distinctive facial dysmorphia, hematologic abnormalities, and cardiac defects. We found that the Ras/MAPK pathway as well as Rac and Stat3 were activated in the mutant hearts. These data provide in vivo molecular and cellular evidence that Sos1 is a GEF for Rac under physiological conditions and suggest that Rac and Stat3 activation might contribute to NS phenotypes. Furthermore, prenatal administration of a MEK inhibitor ameliorated the embryonic lethality, cardiac defects, and NS features of the homozygous mutant mice, demonstrating that this signaling pathway might represent a promising therapeutic target for NS. PMID:21041952

  15. Cell cycle arrest in the jewel wasp Nasonia vitripennis in larval diapause.

    Science.gov (United States)

    Shimizu, Yuta; Mukai, Ayumu; Goto, Shin G

    2018-04-01

    Insects enter diapause to synchronise their life cycle with biotic and abiotic environmental conditions favourable for their development, reproduction, and survival. One of the most noticeable characteristics of diapause is the blockage of ontogeny. Although this blockage should occur with the cessation of cellular proliferation, i.e. cell cycle arrest, it was confirmed only in a few insect species and information on the molecular pathways involved in cell cycle arrest is limited. In the present study, we investigated developmental and cell cycle arrest in diapause larvae of the jewel wasp Nasonia vitripennis. Developmental and cell cycle arrest occur in the early fourth instar larval stage of N. vitripennis under short days. By entering diapause, the S fraction of the cell cycle disappears and approximately 80% and 20% of cells arrest their cell cycle in the G0/G1 and G2 phases, respectively. We further investigated expression of cell cycle regulatory genes and some housekeeping genes to dissect molecular mechanisms underlying the cell cycle arrest. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 7A.06: MATERNAL OBESITY AND THE DEVELOPMENTAL PROGRAMMING OF HYPERTENSION: ALTERED LEPTIN SIGNALLING PATHWAY IN THE CENTRAL NERVOUS SYSTEM.

    Science.gov (United States)

    Lim, J; Burke, S; Head, G A

    2015-06-01

    The prevalence of obesity in women among child baring age is increasing and this has been parallel to the increase in obesity in general population around the world. We investigated the trans-generational 'programming' of leptin signalling in the central nervous system (CNS) to increase blood pressure (BP), heart rate (HR) and renal sympathetic nerve activity (RSNA) following a high fat diet (HFD)feeding in mothers. Female New Zealand White rabbits were fed a high fat (13%) diet (mHFD) or a control diet (mCD) prior mating and during pregnancy. Kittens from mCD rabbits were subdivided and fed HFD for 10days (mCD10dHFD) at 15 weeks of age. All rabbits received an intracerebroventricular (ICV) catheter into the lateral ventricle and a recording electrode on the left renal nerve. Experiments were conducted in conscious rabbits and BP, HR and RSNA was measured. Rabbits received an increasing doses of ICV Melanocortin receptor antagonist (SHU9119),alpha-Melanocortin stimulating hormone (alpha-MSH) and a single dose of Leptin antagonist. ICV SHU9119 reduced BP (-5.8 ± 0.7mmHg and -4.1 ± 0.9mmHg) and RSNA (-2.4 ± 0.3 nu and -0.7 ± 0.3 nu) in mHFD and mCD10dHFD rabbits (P fat was increased (50%) in all rabbits that had HFD. Obesity during pregnancy 'programs' leptin signalling pathway in the CNS of the offspring during development. Leptin via activation of melanocirtin pathway plays a key role in the CNS contributing to the pressor and tachycardic effects as well as renal sympathetic nerve activity in the pathophysiology of obesity.

  17. How Metamorphosis Is Different in Plethodontids: Larval Life History Perspectives on Life-Cycle Evolution

    Science.gov (United States)

    Beachy, Christopher K.; Ryan, Travis J.; Bonett, Ronald M.

    2017-01-01

    Plethodontid salamanders exhibit biphasic, larval form paedomorphic, and direct developing life cycles. This diversity of developmental strategies exceeds that of any other family of terrestrial vertebrate. Here we compare patterns of larval development among the three divergent lineages of biphasic plethodontids and other salamanders. We discuss how patterns of life-cycle evolution and larval ecology might have produced a wide array of larval life histories. Compared with many other salamanders, most larval plethodontids have relatively slow growth rates and sometimes exceptionally long larval periods (up to 60 mo). Recent phylogenetic analyses of life-cycle evolution indicate that ancestral plethodontids were likely direct developers. If true, then biphasic and paedomorphic lineages might have been independently derived through different developmental mechanisms. Furthermore, biphasic plethodontids largely colonized stream habitats, which tend to have lower productivity than seasonally ephemeral ponds. Consistent with this, plethodontid larvae grow very slowly, and metamorphic timing does not appear to be strongly affected by growth history. On the basis of this, we speculate that feeding schedules and stress hormones might play a comparatively reduced role in governing the timing of metamorphosis of stream-dwelling salamanders, particularly plethodontids. PMID:29269959

  18. DEVELOPMENTAL TAXONOMY OF CONDUCT DISORDER

    OpenAIRE

    Jelena Kostić; Milkica Nešić; Jasminka Marković; Miodrag Stanković

    2015-01-01

    Conduct disorder is a heterogeneous disorder in terms of etiology, course and prognosis, and currently, there is no singular model that would describe the development of the disorder. The results of empirical research on males confirm this heterogeneity, as they point out to two possible developmental pathways: childhood-onset and adolescentonset type. This paper presents the basic elements of developmental taxonomic theory which argues that there are two different developmental pathways to c...

  19. Of tests, trochs, shells, and spicules: Development of the basal mollusk Wirenia argentea (Solenogastres) and its bearing on the evolution of trochozoan larval key features

    DEFF Research Database (Denmark)

    Todt, Christiane; Wanninger, Andreas

    2010-01-01

    ) to be derived. Larval characters are central in these discussions, specifically the larval test (calymma, apical cap), the ontogeny of the epidermal scleritome, and the proposed absence of larval protonephridia. To date, developmental data are available for five solenogaster species, but most reports...... a fully developed foregut, but the midgut and hindgut are not yet interconnected. CONCLUSIONS: Solenogastres develop via a trochophore-like lecitotrophic larva with a preoral apical cap that at least partly represents an enlarged prototrochal area. Homology of this larval type (pericalymma larva) to test...

  20. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a ...

  1. Larval outbreaks in West Greenland

    DEFF Research Database (Denmark)

    Lund, Magnus; Raundrup, Katrine; Westergaard-Nielsen, Andreas

    2017-01-01

    effects of a larval outbreak in 2011 on vegetation productivity and CO2 exchange. We estimate a decreased carbon (C) sink strength in the order of 118–143 g C m−2, corresponding to 1210–1470 tonnes C at the Kobbefjord catchment scale. The decreased C sink was, however, counteracted the following years...

  2. Kauri seeds and larval somersaults

    DEFF Research Database (Denmark)

    Dupont, Steen Thorleif

    2012-01-01

    The trunk morphology of the larvae of the kauri pine (Agathis) seed infesting moth Agathiphaga is described using conventional, polarization, and scanning electron microscopy. The pine seed chamber formed by the larva is also described and commented on. The simple larval chaetotaxy includes more ...

  3. Effects of temperature and dietary nitrogen on genetic variation and covariation in gypsy moth larval performance traits

    Directory of Open Access Journals (Sweden)

    Janković-Tomanić Milena

    2012-01-01

    Full Text Available To assess the plastic and genetic components of variation in responses of gypsy moth (Lymantria dispar 4th instar larvae to temperature and food quality, we applied a split-family four-environment experimental design where full-sibs were reared on two constant temperatures (23°C and 28°C and two concentrations of dietary nitrogen (1.5 and 3.7% dry weight. A temperature of 28°C and low dietary nitrogen decreased larval weight and prolonged larval developmental time, while viability was not affected. Only a marginally significant interaction between the two environmental factors was found for larval weight. The broad-sense heritability for larval developmental time did not change across environments, and across-environment genetic correlations were close to one. Heritability for larval weight depended on environmental and across-environmental genetic correlations that were not significant. There was no evidence of a trade-off between developmental time and larval weight. The implications of the obtained results for the evolution of phenotypic plasticity in complex environments are discussed. [Acknowledgments. This work was supported by Ministry of Education and Science of Serbia, grant No. 173027.

  4. Predator-induced larval cloning in the sand dollar Dendraster excentricus: might mothers matter?

    Science.gov (United States)

    Vaughn, Dawn

    2009-10-01

    Predator-induced cloning in echinoid larvae, with reduced size a consequence of cloning, is a dramatic modification of development and a novel response to risks associated with prolonged planktonic development. Recent laboratory studies demonstrate that exposure to stimuli from predators (i.e., fish mucus) induces cloning in the pluteus larvae (plutei) of Dendraster excentricus. However, the timing and incidence of cloning and size reduction of unrelated conspecific plutei differed across experiments. A variable cloning response suggests the effects of such factors as cue quality, egg provisioning, maternal experience, and genetic background, indicating that the potential advantages of cloning as an adaptive response to predators are not available to all larvae. This study tested the hypothesis that cloning in D. excentricus plutei is maternally influenced. Plutei from three half-sibling larval families (different mothers, same father) were exposed to fish mucus for 9 days during early development. Cloning was inferred in a percentage of plutei from each family; however, the rate and success of cloning differed significantly among the larval half-siblings. Unexpectedly, all mucus-treated plutei were smaller and developmentally delayed when compared to all plutei reared in the absence of a mucus stimulus. Thus, while the results from this study support the hypothesis of an influence of mothers on cloning of larval offspring, reduced larval size was a uniform response to fish mucus and did not indicate an effect of mothers. Hypotheses of the developmental effects of fish mucus on larval size with or without successful cloning are discussed.

  5. First feeding of larval herring

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter; Støttrup, Josianne

    1985-01-01

    The transition period from endogenous to exogenous feeding by larval herring was investigated in the laboratory for four herring stocks in order to evaluate the chances of survival at the time of fiest feeding. Observations on larval activity, feeding and growth were related to amount of yolk......, visual experience with potential prey organisms prior to first feeding and prey density. Herring larvae did not initiate exogenous feeding until around the time of yolk resorption. The timing of first feeding was not influenced by prior exposure to potential prey organisms during the yolk sac stage....... In the light of these observations, the ecological significance of the yolk sac stage is discussed. Initiation of exogenous feeding was delayed by 1-4 days at a low (7.5 nauplii .cntdot. l-1) compared to a high (120 nauplii .cntdot. l-1) prey density, but even at prey densities corresponding to the lower end...

  6. Flight biomechanics of developmentally-induced size variation in the solitary bee Osmia lignaria

    Science.gov (United States)

    Body size covaries with morphology, functional performance, and fitness. For insects, variation in adult phenotypies are derived from developmental variation in larval growth and metamorphosis. In this study, we asked how larval growth impacted adult morphology in Osmia lignaria—especially traits th...

  7. 'Peer pressure' in larval Drosophila?

    Science.gov (United States)

    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. © 2014. Published by The Company of Biologists Ltd.

  8. Strategic larval decision-making in a bivoltine butterfly.

    Science.gov (United States)

    Friberg, Magne; Dahlerus, Josefin; Wiklund, Christer

    2012-07-01

    In temperate areas, insect larvae must decide between entering winter diapause or developing directly and reproducing in the same season. Long daylength and high temperature promote direct development, which is generally associated with a higher growth rate. In this work, we investigated whether the larval pathway decision precedes the adjustment of growth rate (state-independent), or whether the pathway decision is conditional on the individual's growth rate (state-dependent), in the butterfly Pieris napi. This species typically makes the pathway decision in the penultimate instar. We measured growth rate throughout larval development under two daylengths: slightly shorter and slightly longer than the critical daylength. Results indicate that the pathway decision can be both state-independent and state-dependent; under the shorter daylength condition, most larvae entered diapause, and direct development was chosen exclusively by a small subset of larvae showing the highest growth rates already in the early instars; under the longer daylength condition, most larvae developed directly, and the diapause pathway was chosen exclusively by a small subset of slow-growing individuals. Among the remainder, the choice of pathway was independent of the early growth rate; larvae entering diapause under the short daylength grew as fast as or faster than the direct developers under the longer daylength in the early instars, whereas the direct developers grew faster than the diapausers only in the ultimate instar. Hence, the pathway decision was state-dependent in a subset with a very high or very low growth rate, whereas the decision was state-independent in the majority of the larvae, which made the growth rate adjustment downstream from the pathway decision.

  9. Functional genomics identifies regulators of the phototransduction machinery in the Drosophila larval eye and adult ocelli.

    Science.gov (United States)

    Mishra, Abhishek Kumar; Bargmann, Bastiaan O R; Tsachaki, Maria; Fritsch, Cornelia; Sprecher, Simon G

    2016-02-15

    Sensory perception of light is mediated by specialized Photoreceptor neurons (PRs) in the eye. During development all PRs are genetically determined to express a specific Rhodopsin (Rh) gene and genes mediating a functional phototransduction pathway. While the genetic and molecular mechanisms of PR development is well described in the adult compound eye, it remains unclear how the expression of Rhodopsins and the phototransduction cascade is regulated in other visual organs in Drosophila, such as the larval eye and adult ocelli. Using transcriptome analysis of larval PR-subtypes and ocellar PRs we identify and study new regulators required during PR differentiation or necessary for the expression of specific signaling molecules of the functional phototransduction pathway. We found that the transcription factor Krüppel (Kr) is enriched in the larval eye and controls PR differentiation by promoting Rh5 and Rh6 expression. We also identified Camta, Lola, Dve and Hazy as key genes acting during ocellar PR differentiation. Further we show that these transcriptional regulators control gene expression of the phototransduction cascade in both larval eye and adult ocelli. Our results show that PR cell type-specific transcriptome profiling is a powerful tool to identify key transcriptional regulators involved during several aspects of PR development and differentiation. Our findings greatly contribute to the understanding of how combinatorial action of key transcriptional regulators control PR development and the regulation of a functional phototransduction pathway in both larval eye and adult ocelli. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Developmental Changes for the Hemolymph Metabolome of Silkworm (Bombyx moriL.)

    Science.gov (United States)

    Zhou, Lihong; Li, Huihui; Hao, Fuhua; Li, Ning; Liu, Xin; Wang, Guoliang; Wang, Yulan; Tang, Huiru

    2015-01-01

    Silkworm (Bombyx mori) is a lepidopteran-holometabolic model organism. To understand its developmental biochemistry, we characterized the larval hemolymph metabonome from the third instar to prepupa stage using 1H NMR spectroscopy whilst hemolymph fatty acid composition using GC-FID/MS. We unambiguously assigned more than 60 metabolites, among which tyrosine-o-β-glucuronide, mesaconate, homocarnosine, and picolinate were reported for the first time from the silkworm hemolymph. Phosphorylcholine was the most abundant metabolite in all developmental stages with exception for the periods before the third and fourth molting. We also found obvious developmental dependence for the hemolymph metabonome involving multiple pathways including protein biosyntheses, glycolysis, TCA cycle, the metabolisms of choline amino acids, fatty acids, purines, and pyrimidines. Most hemolymph amino acids had two elevations during the feeding period of the fourth instar and prepupa stage. Trehalose was the major blood sugar before day 8 of the fifth instar, whereas glucose became the major blood sugar after spinning. C16:0, C18:0 and its unsaturated forms were dominant fatty acids in hemolymph. The developmental changes of hemolymph metabonome were associated with dietary nutrient intakes, biosyntheses of cell membrane, pigments, proteins, and energy metabolism. These findings offered essential biochemistry information in terms of the dynamic metabolic changes during silkworm development. PMID:25825269

  11. Developmental Toxicity of Zinc Oxide Nanoparticles to Zebrafish (Danio rerio: A Transcriptomic Analysis.

    Directory of Open Access Journals (Sweden)

    Jin Soo Choi

    Full Text Available Zinc oxide nanoparticles (ZnO NPs are being utilized in an increasing number of fields and commercial applications. While their general toxicity and associated oxidative stress have been extensively studied, the toxicological pathways that they induce in developmental stages are still largely unknown. In this study, the developmental toxicity of ZnO NPs to embryonic/larval zebrafish was investigated. The transcriptional expression profiles induced by ZnO NPs were also investigated to ascertain novel genomic responses related to their specific toxicity pathway. Zebrafish embryos were exposed to 0.01, 0.1, 1, and 10 mg/L ZnO NPs for 96 h post-fertilization. The toxicity of ZnO NPs, based on their Zn concentration, was quite similar to that in embryonic/larval zebrafish exposed to corresponding ZnSO4 concentrations. Pericardial edema and yolk-sac edema were the principal malformations induced by ZnO NPs. Gene-expression profiling using microarrays demonstrated 689 genes that were differentially regulated (fold change >1.5 following exposure to ZnO NPs (498 upregulated, 191 downregulated. Several genes that were differentially regulated following ZnO NP exposure shared similar biological pathways with those observed with ZnSO4 exposure, but six genes (aicda, cyb5d1, edar, intl2, ogfrl2 and tnfsf13b associated with inflammation and the immune system responded specifically to ZnO NPs (either in the opposite direction or were unchanged in ZnSO4 exposure. Real-time reverse-transcription quantitative polymerase chain reaction confirmed that the responses of these genes to ZnO NPs were significantly different from their response to ZnSO4 exposure. ZnO NPs may affect genes related to inflammation and the immune system, resulting in yolk-sac edema and pericardia edema in embryonic/larval developmental stages. These results will assist in elucidating the mechanisms of toxicity of ZnO NPs during development of zebrafish.

  12. Age matters: Developmental stage of Danio rerio larvae influences photomotor response thresholds to diazinion or diphenhydramine

    International Nuclear Information System (INIS)

    Kristofco, Lauren A.; Cruz, Luis Colon; Haddad, Samuel P.; Behra, Martine L.; Chambliss, C. Kevin; Brooks, Bryan W.

    2016-01-01

    Highlights: • Fish behavior impairments by biological active contaminants are limited yet necessary. • Aquatic toxicology assays with 0–4 dpf larval zebrafish are increasingly important. • Larval zebrafish locomotion varied with age and daylight during typical workday hours. • Photomotor behavior to diazinion and diphenhydramine differed by larval zebrafish age. • Behavioral responses of 7–10 dpf zebrafish were markedly more sensitive than 0–4 dpf. - Abstract: Because basic toxicological data is unavailable for the majority of industrial compounds, High Throughput Screening (HTS) assays using the embryonic and larval zebrafish provide promising approaches to define bioactivity profiles and identify potential adverse outcome pathways for previously understudied chemicals. Unfortunately, standardized approaches, including HTS experimental designs, for examining fish behavioral responses to contaminants are rarely available. In the present study, we examined movement behavior of larval zebrafish over 7 days (4–10 days post fertilization or dpf) during typical daylight workday hours to determine whether intrinsic activity differed with age and time of day. We then employed an early life stage approach using the Fish Embryo Test (FET) at multiple developmental ages to evaluate whether photomotor response (PMR) behavior differed with zebrafish age following exposure to diazinon (DZN), a well-studied orthophosphate insecticide, and diphenhydramine (DPH), an antihistamine that also targets serotonin reuptake transporters and the acetylcholine receptor. 72 h studies were conducted at 1–4, 4–7 and 7–10 dpf, followed by behavioral observations using a ViewPoint system at 4, 7 and 10 dpf. Distance traveled and swimming speeds were quantified; nominal treatment levels were analytically verified by isotope-dilution LC–MSMS. Larval zebrafish locomotion displayed significantly different (p < 0.05) activity profiles over the course of typical daylight and

  13. Age matters: Developmental stage of Danio rerio larvae influences photomotor response thresholds to diazinion or diphenhydramine

    Energy Technology Data Exchange (ETDEWEB)

    Kristofco, Lauren A. [Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX (United States); Cruz, Luis Colon [Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico, Medical Sciences Campus, San Juan (Puerto Rico); Haddad, Samuel P. [Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX (United States); Behra, Martine L. [Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico, Medical Sciences Campus, San Juan (Puerto Rico); Chambliss, C. Kevin [Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX (United States); Department of Chemistry, Baylor University, Waco, TX (United States); Brooks, Bryan W., E-mail: Bryan_Brooks@baylor.edu [Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX (United States)

    2016-01-15

    Highlights: • Fish behavior impairments by biological active contaminants are limited yet necessary. • Aquatic toxicology assays with 0–4 dpf larval zebrafish are increasingly important. • Larval zebrafish locomotion varied with age and daylight during typical workday hours. • Photomotor behavior to diazinion and diphenhydramine differed by larval zebrafish age. • Behavioral responses of 7–10 dpf zebrafish were markedly more sensitive than 0–4 dpf. - Abstract: Because basic toxicological data is unavailable for the majority of industrial compounds, High Throughput Screening (HTS) assays using the embryonic and larval zebrafish provide promising approaches to define bioactivity profiles and identify potential adverse outcome pathways for previously understudied chemicals. Unfortunately, standardized approaches, including HTS experimental designs, for examining fish behavioral responses to contaminants are rarely available. In the present study, we examined movement behavior of larval zebrafish over 7 days (4–10 days post fertilization or dpf) during typical daylight workday hours to determine whether intrinsic activity differed with age and time of day. We then employed an early life stage approach using the Fish Embryo Test (FET) at multiple developmental ages to evaluate whether photomotor response (PMR) behavior differed with zebrafish age following exposure to diazinon (DZN), a well-studied orthophosphate insecticide, and diphenhydramine (DPH), an antihistamine that also targets serotonin reuptake transporters and the acetylcholine receptor. 72 h studies were conducted at 1–4, 4–7 and 7–10 dpf, followed by behavioral observations using a ViewPoint system at 4, 7 and 10 dpf. Distance traveled and swimming speeds were quantified; nominal treatment levels were analytically verified by isotope-dilution LC–MSMS. Larval zebrafish locomotion displayed significantly different (p < 0.05) activity profiles over the course of typical daylight and

  14. Models of prey capture in larval fish

    NARCIS (Netherlands)

    Drost, M.R.

    1986-01-01

    The food uptake of larval carp and pike is described from high speed movies with synchronous lateral and ventral views.

    During prey intake by larval fishes the velocities of the created suction flow are high relative to their own size: 0.3 m/s for carp larvae of 6

  15. The Co-Occurring Development of Executive Function Skills and Receptive Vocabulary in Preschool-Aged Children: A Look at the Direction of the Developmental Pathways

    Science.gov (United States)

    Weiland, Christina; Barata, M. Clara; Yoshikawa, Hirokazu

    2014-01-01

    Despite consensus in the developmental literature regarding the role of executive function (EF) skills in supporting the development of language skills during the preschool years, we know relatively little about the associations between EF skills, including all EF components, and vocabulary skills among preschool-aged children. In this paper, we…

  16. Isolation and culture of larval cells from C. elegans.

    Directory of Open Access Journals (Sweden)

    Sihui Zhang

    Full Text Available Cell culture is an essential tool to study cell function. In C. elegans the ability to isolate and culture cells has been limited to embryonically derived cells. However, cells or blastomeres isolated from mixed stage embryos terminally differentiate within 24 hours of culture, thus precluding post-embryonic stage cell culture. We have developed an efficient and technically simple method for large-scale isolation and primary culture of larval-stage cells. We have optimized the treatment to maximize cell number and minimize cell death for each of the four larval stages. We obtained up to 7.8×10(4 cells per microliter of packed larvae, and up to 97% of adherent cells isolated by this method were viable for at least 16 hours. Cultured larval cells showed stage-specific increases in both cell size and multinuclearity and expressed lineage- and cell type-specific reporters. The majority (81% of larval cells isolated by our method were muscle cells that exhibited stage-specific phenotypes. L1 muscle cells developed 1 to 2 wide cytoplasmic processes, while L4 muscle cells developed 4 to 14 processes of various thicknesses. L4 muscle cells developed bands of myosin heavy chain A thick filaments at the cell center and spontaneously contracted ex vivo. Neurons constituted less than 10% of the isolated cells and the majority of neurons developed one or more long, microtubule-rich protrusions that terminated in actin-rich growth cones. In addition to cells such as muscle and neuron that are high abundance in vivo, we were also able to isolate M-lineage cells that constitute less than 0.2% of cells in vivo. Our novel method of cell isolation extends C. elegans cell culture to larval developmental stages, and allows use of the wealth of cell culture tools, such as cell sorting, electrophysiology, co-culture, and high-resolution imaging of subcellular dynamics, in investigation of post-embryonic development and physiology.

  17. [Canine peritoneal larval cestodosis caused by Mesocestoides spp. larval stages].

    Science.gov (United States)

    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.

  18. Reactivation of larval keratin gene (krt62.L) in blastema epithelium during Xenopus froglet limb regeneration.

    Science.gov (United States)

    Satoh, Akira; Mitogawa, Kazumasa; Saito, Nanami; Suzuki, Miyuki; Suzuki, Ken-Ichi T; Ochi, Haruki; Makanae, Aki

    2017-12-15

    Limb regeneration is considered a form of limb redevelopment because of the molecular and morphological similarities. Forming a regeneration blastema is, in essence, creating a developing limb bud in an adult body. This reactivation of a developmental process in a mature body is worth studying. Xenopus laevis has a biphasic life cycle that involves distinct larval and adult stages. These distinct developmental stages are useful for investigating the reactivation of developmental processes in post-metamorphic frogs (froglets). In this study, we focused on the re-expression of a larval gene (krt62.L) during Xenopus froglet limb regeneration. Recently renamed krt62.L, this gene was known as the larval keratin (xlk) gene, which is specific to larval-tadpole stages. During limb regeneration in a froglet, krt62.L was re-expressed in a basal layer of blastema epithelium, where adult-specific keratin (Krt12.6.S) expression was also observable. Nerves produce important regulatory factors for amphibian limb regeneration, and also play a role in blastema formation and maintenance. The effect of nerve function on krt62.L expression could be seen in the maintenance of krt62.L expression, but not in its induction. When an epidermis-stripped limb bud was grafted in a froglet blastema, the grafted limb bud could reach the digit-forming stage. This suggests that krt62.L-positive froglet blastema epithelium is able to support the limb development process. These findings imply that the developmental process is locally reactivated in an postmetamorphic body during limb regeneration. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Resource Limitation, Controphic Ostracod Density and Larval Mosquito Development.

    Directory of Open Access Journals (Sweden)

    Raylea Rowbottom

    Full Text Available Aquatic environments can be restricted with the amount of available food resources especially with changes to both abiotic and biotic conditions. Mosquito larvae, in particular, are sensitive to changes in food resources. Resource limitation through inter-, and intra-specific competition among mosquitoes are known to affect both their development and survival. However, much less is understood about the effects of non-culicid controphic competitors (species that share the same trophic level. To address this knowledge gap, we investigated and compared mosquito larval development, survival and adult size in two experiments, one with different densities of non-culicid controphic conditions and the other with altered resource conditions. We used Aedes camptorhynchus, a salt marsh breeding mosquito and a prominent vector for Ross River virus in Australia. Aedes camptorhynchus usually has few competitors due to its halo-tolerance and distribution in salt marshes. However, sympatric ostracod micro-crustaceans often co-occur within these salt marshes and can be found in dense populations, with field evidence suggesting exploitative competition for resources. Our experiments demonstrate resource limiting conditions caused significant increases in mosquito developmental times, decreased adult survival and decreased adult size. Overall, non-culicid exploitation experiments showed little effect on larval development and survival, but similar effects on adult size. We suggest that the alterations of adult traits owing to non-culicid controphic competition has potential to extend to vector-borne disease transmission.

  20. Strongyloides stercoralis age-1: a potential regulator of infective larval development in a parasitic nematode.

    Directory of Open Access Journals (Sweden)

    Jonathan D Stoltzfus

    Full Text Available Infective third-stage larvae (L3i of the human parasite Strongyloides stercoralis share many morphological, developmental, and behavioral attributes with Caenorhabditis elegans dauer larvae. The 'dauer hypothesis' predicts that the same molecular genetic mechanisms control both dauer larval development in C. elegans and L3i morphogenesis in S. stercoralis. In C. elegans, the phosphatidylinositol-3 (PI3 kinase catalytic subunit AGE-1 functions in the insulin/IGF-1 signaling (IIS pathway to regulate formation of dauer larvae. Here we identify and characterize Ss-age-1, the S. stercoralis homolog of the gene encoding C. elegans AGE-1. Our analysis of the Ss-age-1 genomic region revealed three exons encoding a predicted protein of 1,209 amino acids, which clustered with C. elegans AGE-1 in phylogenetic analysis. We examined temporal patterns of expression in the S. stercoralis life cycle by reverse transcription quantitative PCR and observed low levels of Ss-age-1 transcripts in all stages. To compare anatomical patterns of expression between the two species, we used Ss-age-1 or Ce-age-1 promoter::enhanced green fluorescent protein reporter constructs expressed in transgenic animals for each species. We observed conservation of expression in amphidial neurons, which play a critical role in developmental regulation of both dauer larvae and L3i. Application of the PI3 kinase inhibitor LY294002 suppressed L3i in vitro activation in a dose-dependent fashion, with 100 µM resulting in a 90% decrease (odds ratio: 0.10, 95% confidence interval: 0.08-0.13 in the odds of resumption of feeding for treated L3i in comparison to the control. Together, these data support the hypothesis that Ss-age-1 regulates the development of S. stercoralis L3i via an IIS pathway in a manner similar to that observed in C. elegans dauer larvae. Understanding the mechanisms by which infective larvae are formed and activated may lead to novel control measures and treatments for

  1. p53 is required for brain growth but is dispensable for resistance to nutrient restriction during Drosophila larval development.

    Science.gov (United States)

    Contreras, Esteban G; Sierralta, Jimena; Glavic, Alvaro

    2018-01-01

    Animal growth is influenced by the genetic background and the environmental circumstances. How genes promote growth and coordinate adaptation to nutrient availability is still an open question. p53 is a transcription factor that commands the cellular response to different types of stresses. In adult Drosophila melanogaster, p53 regulates the metabolic adaptation to nutrient restriction that supports fly viability. Furthermore, the larval brain is protected from nutrient restriction in a phenomenon called 'brain sparing'. Therefore, we hypothesised that p53 may regulate brain growth and show a protective role over brain development under nutrient restriction. Here, we studied the function of p53 during brain growth in normal conditions and in animals subjected to developmental nutrient restriction. We showed that p53 loss of function reduced animal growth and larval brain size. Endogenous p53 was expressed in larval neural stem cells, but its levels and activity were not affected by nutritional stress. Interestingly, p53 knockdown only in neural stem cells was sufficient to decrease larval brain growth. Finally, we showed that in p53 mutant larvae under nutrient restriction, the energy storage levels were not altered, and these larvae generated adults with brains of similar size than wild-type animals. Using genetic approaches, we demonstrate that p53 is required for proper growth of the larval brain. This developmental role of p53 does not have an impact on animal resistance to nutritional stress since brain growth in p53 mutants under nutrient restriction is similar to control animals.

  2. Relative importance of temperature and diet to larval development and adult size of the winter stonefly, Soyedina carolinensis (Plecoptera: Nemouridae)

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, B.W.; Vannote, R.L.; Dodds, P.J.

    1986-02-01

    Soyedina carolinensis Claassen, a leaf shredding stonefly, was reared in a series of three laboratory experiments from early instar to adult on different species of deciduous leaves and at various constant and fluctuating temperature regimes. Experiment 1, which involved rearing larvae on fourteen different leaf diets at ambient stream temperatures, showed that diet significantly affected larval growth and adult size but did not affect overall developmental time. Experiment 2, which involved rearing larvae on five different leaf diets at each of three fluctuating temperature regimes, showed that: adding 6/sup 0/C to the normal temperature regime of WCC was lethal to 99% of the larvae regardless of diet; and warming WCC by 3/sup 0/C did not affect developmental time but did significantly reduce adult size relative to adults reared at WCC temperatures on certain diets. Experiment 3, which involved rearing larvae on five different leaf diets at each of five constant temperatures showed that: temperature significantly affected the mortality, growth, and development time of larvae whereas diet only affected larval growth and mortality; temperatures at or near 10/sup 0/C yielded maximum larval growth and survival for most diets; at 5/sup 0/C, larval mortality was high and growth was low resulting in a few small adults for most diets; larval mortality was at or near 100% at 15/sup 0/C regardless of diet; and no larvae survived at 20 and 25/sup 0/C.

  3. The Arabidopsis Rho of Plants GTPase AtROP6 Functions in Developmental and Pathogen Response Pathways1[C][W][OA

    Science.gov (United States)

    Poraty-Gavra, Limor; Zimmermann, Philip; Haigis, Sabine; Bednarek, Paweł; Hazak, Ora; Stelmakh, Oksana Rogovoy; Sadot, Einat; Schulze-Lefert, Paul; Gruissem, Wilhelm; Yalovsky, Shaul

    2013-01-01

    How plants coordinate developmental processes and environmental stress responses is a pressing question. Here, we show that Arabidopsis (Arabidopsis thaliana) Rho of Plants6 (AtROP6) integrates developmental and pathogen response signaling. AtROP6 expression is induced by auxin and detected in the root meristem, lateral root initials, and leaf hydathodes. Plants expressing a dominant negative AtROP6 (rop6DN) under the regulation of its endogenous promoter are small and have multiple inflorescence stems, twisted leaves, deformed leaf epidermis pavement cells, and differentially organized cytoskeleton. Microarray analyses of rop6DN plants revealed that major changes in gene expression are associated with constitutive salicylic acid (SA)-mediated defense responses. In agreement, their free and total SA levels resembled those of wild-type plants inoculated with a virulent powdery mildew pathogen. The constitutive SA-associated response in rop6DN was suppressed in mutant backgrounds defective in SA signaling (nonexpresser of PR genes1 [npr1]) or biosynthesis (salicylic acid induction deficient2 [sid2]). However, the rop6DN npr1 and rop6DN sid2 double mutants retained the aberrant developmental phenotypes, indicating that the constitutive SA response can be uncoupled from ROP function(s) in development. rop6DN plants exhibited enhanced preinvasive defense responses to a host-adapted virulent powdery mildew fungus but were impaired in preinvasive defenses upon inoculation with a nonadapted powdery mildew. The host-adapted powdery mildew had a reduced reproductive fitness on rop6DN plants, which was retained in mutant backgrounds defective in SA biosynthesis or signaling. Our findings indicate that both the morphological aberrations and altered sensitivity to powdery mildews of rop6DN plants result from perturbations that are independent from the SA-associated response. These perturbations uncouple SA-dependent defense signaling from disease resistance execution. PMID

  4. Developmental constraint of insect audition

    Directory of Open Access Journals (Sweden)

    Strauß Johannes

    2006-12-01

    Full Text Available Abstract Background Insect ears contain very different numbers of sensory cells, from only one sensory cell in some moths to thousands of sensory cells, e.g. in cicadas. These differences still await functional explanation and especially the large numbers in cicadas remain puzzling. Insects of the different orders have distinct developmental sequences for the generation of auditory organs. These sensory cells might have different functions depending on the developmental stages. Here we propose that constraints arising during development are also important for the design of insect ears and might influence cell numbers of the adults. Presentation of the hypothesis We propose that the functional requirements of the subadult stages determine the adult complement of sensory units in the auditory system of cicadas. The hypothetical larval sensory organ should function as a vibration receiver, representing a functional caenogenesis. Testing the hypothesis Experiments at different levels have to be designed to test the hypothesis. Firstly, the neuroanatomy of the larval sense organ should be analyzed to detail. Secondly, the function should be unraveled neurophysiologically and behaviorally. Thirdly, the persistence of the sensory cells and the rebuilding of the sensory organ to the adult should be investigated. Implications of the hypothesis Usually, the evolution of insect ears is viewed with respect to physiological and neuronal mechanisms of sound perception. This view should be extended to the development of sense organs. Functional requirements during postembryonic development may act as constraints for the evolution of adult organs, as exemplified with the auditory system of cicadas.

  5. Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds.

    Science.gov (United States)

    Eggleston, David B; Lillis, Ashlee; Bohnenstiehl, DelWayne R

    2016-01-01

    We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites.

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

    Science.gov (United States)

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

    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.

  7. Exposure to waterborne Cu inhibits cutaneous Na⁺ uptake in post-hatch larval rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Zimmer, Alex M; Brauner, Colin J; Wood, Chris M

    2014-05-01

    In freshwater rainbow trout (Oncorhynchus mykiss), two common responses to acute waterborne copper (Cu) exposure are reductions in ammonia excretion and Na(+) uptake at the gills, with the latter representing the likely lethal mechanism of action for Cu in adult fish. Larval fish, however, lack a functional gill following hatch and rely predominantly on cutaneous exchange, yet represent the most Cu-sensitive life stage. It is not known if Cu toxicity in larval fish occurs via the skin or gills. The present study utilized divided chambers to assess cutaneous and branchial Cu toxicity over larval development, using disruptions in ammonia excretion (Jamm) and Na(+) uptake (Jin(Na)) as toxicological endpoints. Early in development (early; 3 days post-hatch; dph), approximately 95% of Jamm and 78% of Jin(Na) occurred cutaneously, while in the late developmental stage (late; 25 dph), the gills were the dominant site of exchange (83 and 87% of Jamm and Jin(Na), respectively). Exposure to 50 μg/l Cu led to a 49% inhibition of Jamm in the late developmental stage only, while in the early and middle developmental (mid; 17 dph) stages, Cu had no effect on Jamm. Jin(Na), however, was significantly inhibited by Cu exposure at the early (53% reduction) and late (47% reduction) stages. Inhibition at the early stage of development was mediated by a reduction in cutaneous uptake, representing the first evidence of cutaneous metal toxicity in an intact aquatic organism. The inhibitions of both Jamm and Jin(Na) in the late developmental stage occurred via a reduction in branchial exchange only. The differential responses of the skin and gills to Cu exposure suggest that the mechanisms of Jamm and Jin(Na) and/or Cu toxicity differ between these tissues. Exposure to 20μg/l Cu revealed that Jamm is the more Cu-sensitive process. The results presented here have important implications in predicting metal toxicity in larval fish. The Biotic Ligand Model (BLM) is currently used to predict

  8. Building a developmental toxicity ontology.

    Science.gov (United States)

    Baker, Nancy; Boobis, Alan; Burgoon, Lyle; Carney, Edward; Currie, Richard; Fritsche, Ellen; Knudsen, Thomas; Laffont, Madeleine; Piersma, Aldert H; Poole, Alan; Schneider, Steffen; Daston, George

    2018-04-03

    As more information is generated about modes of action for developmental toxicity and more data are generated using high-throughput and high-content technologies, it is becoming necessary to organize that information. This report discussed the need for a systematic representation of knowledge about developmental toxicity (i.e., an ontology) and proposes a method to build one based on knowledge of developmental biology and mode of action/ adverse outcome pathways in developmental toxicity. This report is the result of a consensus working group developing a plan to create an ontology for developmental toxicity that spans multiple levels of biological organization. This report provide a description of some of the challenges in building a developmental toxicity ontology and outlines a proposed methodology to meet those challenges. As the ontology is built on currently available web-based resources, a review of these resources is provided. Case studies on one of the most well-understood morphogens and developmental toxicants, retinoic acid, are presented as examples of how such an ontology might be developed. This report outlines an approach to construct a developmental toxicity ontology. Such an ontology will facilitate computer-based prediction of substances likely to induce human developmental toxicity. © 2018 Wiley Periodicals, Inc.

  9. Predator avoidance performance of larval fathead minnows (Pimephales promelas) following short-term exposure to estrogen mixtures

    Science.gov (United States)

    McGee, M.R.; Julius, M.L.; Vajda, A.M.; Norris, D.O.; Barber, L.B.; Schoenfuss, H.L.

    2009-01-01

    Aquatic organisms exposed to endocrine disrupting compounds (EDCs) at early life-stages may have reduced reproductive fitness via disruption of reproductive and non-reproductive behavioral and physiological pathways. Survival to reproductive age relies upon optimal non-reproductive trait expression, such as adequate predator avoidance responses, which may be impacted through EDC exposure. During a predator–prey confrontation, larval fish use an innate C-start escape behavior to rapidly move away from an approaching threat. We tested the hypotheses that (1) larval fathead minnows exposed to estrogens, a primary class of EDCs, singularly or in mixture, suffer a reduced ability to perform an innate C-start behavior when faced with a threat stimulus; (2) additive effects will cause greater reductions in C-start behavior; and (3) effects will differ among developmental stages. In this study, embryos (post-fertilization until hatching) were exposed for 5 days to environmentally relevant concentrations of estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) singularly and in mixture. Exposed embryos were allowed to hatch and grow in control well water until 12 days old. Similarly, post-hatch fathead minnows were exposed for 12 days to these compounds. High-speed (1000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency period, escape velocity, and total escape response (combination of latency period and escape velocity). When tested 12 days post-hatch, only E1 adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 days post-hatch did not exhibit altered escape responses when exposed to E1, while adverse responses were seen in E2 and the estrogen mixture. Ethinylestradiol exposure did not elicit changes in escape behaviors at either developmental stage. The direct impact of reduced C-start performance on

  10. Gene expression patterns during the larval development of European sea bass (dicentrarchus labrax) by microarray analysis.

    Science.gov (United States)

    Darias, M J; Zambonino-Infante, J L; Hugot, K; Cahu, C L; Mazurais, D

    2008-01-01

    During the larval period, marine teleosts undergo very fast growth and dramatic changes in morphology, metabolism, and behavior to accomplish their metamorphosis into juvenile fish. Regulation of gene expression is widely thought to be a key mechanism underlying the management of the biological processes required for harmonious development over this phase of life. To provide an overall analysis of gene expression in the whole body during sea bass larval development, we monitored the expression of 6,626 distinct genes at 10 different points in time between 7 and 43 days post-hatching (dph) by using heterologous hybridization of a rainbow trout cDNA microarray. The differentially expressed genes (n = 485) could be grouped into two categories: genes that were generally up-expressed early, between 7 and 23 dph, and genes up-expressed between 25 and 43 dph. Interestingly, among the genes regulated during the larval period, those related to organogenesis, energy pathways, biosynthesis, and digestion were over-represented compared with total set of analyzed genes. We discuss the quantitative regulation of whole-body contents of these specific transcripts with regard to the ontogenesis and maturation of essential functions that take place over larval development. Our study is the first utilization of a transcriptomic approach in sea bass and reveals dynamic changes in gene expression patterns in relation to marine finfish larval development.

  11. Age matters: Developmental stage of Danio rerio larvae influences photomotor response thresholds to diazinion or diphenhydramine

    Science.gov (United States)

    Kristofco, Lauren A.; Cruz, Luis Colon; Haddad, Samuel P.; Behra, Martine L; Chambliss, C. Kevin; Brooks, Bryan W.

    2016-01-01

    Because basic toxicological data is unavailable for the majority of industrial compounds, High Throughput Screening (HTS) assays using the embryonic and larval zebrafish provide promising approaches to define bioactivity profiles and identify potential adverse outcome pathways for previously understudied chemicals. Unfortunately, standardized approaches, including HTS experimental designs, for examining fish behavioral responses to contaminants are rarely available. In the present study, we examined movement behavior of larval zebrafish over 7 days (4–10 days post fertilization or dpf) during typical daylight workday hours to determine whether intrinsic activity differed with age and time of day. We then employed an early life stage approach using the Fish Embryo Test (FET) at multiple developmental ages to evaluate whether photomotor response (PMR) behavior differed with zebrafish age following exposure to diazinon (DZN), a well-studied orthophosphate insecticide, and diphenhydramine (DPH), an antihistamine that also targets serotonin reuptake transporters and the acetylcholine receptor. 72 h studies were conducted at 1–4, 4–7 and 7–10 dpf, followed by behavioral observations using a ViewPoint system at 4, 7 and 10 dpf. Distance traveled and swimming speeds were quantified; nominal treatment levels were analytically verified by isotope-dilution LC-MSMS. Larval zebrafish locomotion displayed significantly different (p environmentally realistic lowest observed effect concentration of 200 ng/L. Though ELS and FET studies with zebrafish typically focus on mortality or teratogenicity in 0–4 dpf organisms, behavioral responses of slightly older fish were several orders of magnitude more sensitive to DPH. Our observations highlight the importance of understanding the influence of time of day on intrinsic locomotor activity, and the age-specific hazards of aquatic contaminants to fish behavior. PMID:26431593

  12. Developmental Immunotoxicity

    Science.gov (United States)

    Animal models suggest that the immature immune system is more susceptible to xenobiotics than the fully mature system, and sequelae of developmental immunotoxicant exposure may be persistent well into adulthood. Immune maturation may be delayed by xenobiotic exposure and recover...

  13. Age- and Wavelength-Dependency of Drosophila Larval Phototaxis and Behavioral Responses to Natural Lighting Conditions

    Directory of Open Access Journals (Sweden)

    Simon G. Sprecher

    2017-04-01

    Full Text Available Animals use various environmental cues as key determinant for their behavioral decisions. Visual systems are hereby responsible to translate light-dependent stimuli into neuronal encoded information. Even though the larval eyes of the fruit fly Drosophila melanogaster are comparably simple, they comprise two types of photoreceptor neurons (PRs, defined by different Rhodopsin genes expressed. Recent findings support that for light avoidance Rhodopsin5 (Rh5 expressing photoreceptors are crucial, while Rhodopsin6 (Rh6 expressing photoreceptors are dispensable under laboratory conditions. However, it remains debated how animals change light preference during larval live. We show that larval negative phototaxis is age-independent as it persists in larvae from foraging to wandering developmental stages. Moreover, if spectrally different Rhodopsins are employed for the detection of different wavelength of light remains unexplored. We found that negative phototaxis can be elicit by light with wavelengths ranging from ultraviolet (UV to green. This behavior is uniquely mediated by Rh5 expressing photoreceptors, and therefore suggest that this photoreceptor-type is able to perceive UV up to green light. In contrast to laboratory our field experiments revealed that Drosophila larvae uses both types of photoreceptors under natural lighting conditions. All our results, demonstrate that Drosophila larval eyes mediate avoidance of light stimuli with a wide, ecological relevant range of quantity (intensities and quality (wavelengths. Thus, the two photoreceptor-types appear more likely to play a role in different aspects of phototaxis under natural lighting conditions, rather than color discrimination.

  14. Larval starvation improves metabolic response to adult starvation in honey bees (Apis mellifera L.).

    Science.gov (United States)

    Wang, Ying; Campbell, Jacob B; Kaftanoglu, Osman; Page, Robert E; Amdam, Gro V; Harrison, Jon F

    2016-04-01

    Environmental changes during development have long-term effects on adult phenotypes in diverse organisms. Some of the effects play important roles in helping organisms adapt to different environments, such as insect polymorphism. Others, especially those resulting from an adverse developmental environment, have a negative effect on adult health and fitness. However, recent studies have shown that those phenotypes influenced by early environmental adversity have adaptive value under certain (anticipatory) conditions that are similar to the developmental environment, though evidence is mostly from morphological and behavioral observations and it is still rare at physiological and molecular levels. In the companion study, we applied a short-term starvation treatment to fifth instar honey bee larvae and measured changes in adult morphology, starvation resistance, hormonal and metabolic physiology and gene expression. Our results suggest that honey bees can adaptively respond to the predicted nutritional stress. In the present study, we further hypothesized that developmental starvation specifically improves the metabolic response of adult bees to starvation instead of globally affecting metabolism under well-fed conditions. Here, we produced adult honey bees that had experienced a short-term larval starvation, then we starved them for 12 h and monitored metabolic rate, blood sugar concentrations and metabolic reserves. We found that the bees that experienced larval starvation were able to shift to other fuels faster and better maintain stable blood sugar levels during starvation. However, developmental nutritional stress did not change metabolic rates or blood sugar levels in adult bees under normal conditions. Overall, our study provides further evidence that early larval starvation specifically improves the metabolic responses to adult starvation in honey bees. © 2016. Published by The Company of Biologists Ltd.

  15. The largest specimen of Apateon and the life history pathway of neoteny in the Paleozoic temnospondyl family Branchiosauridae

    Directory of Open Access Journals (Sweden)

    N. B. Fröbisch

    2009-02-01

    Full Text Available Two distinct developmental trajectories, metamorphosis and neoteny (the retention of larval somatic features in adult animals, have been reported for the small gill-bearing branchiosaurids of the Late Carboniferous and Early Permian of central Europe. Based on a very large specimen of the species Apateon caducus (Ammon, 1889, anatomical features characteristic for the neotenic phenotype of branchiosaurids are described. Large neotenes lack changes that occur during a short phase of transformation into terrestrial adults (metamorphosis, such as ossification of the braincase and palatoquadrate and intercentra, further ossification of the girdles and formation of muscle attachment scars and processes on the limb bones. They also lack a distinct sculpturing of the dermal skull roofing elements with deep polygonal ridges and grooves. Instead, larval somatic features are retained including ossified branchial denticles indicative of open gill slits and accentuated larval-type sculpturing of the dermal skull roof. Large size, high degree of ossification as compared to the larvae, and the presence of uncinate processes on the ribs clearly demonstrate an adult ontogenetic stage. Neotenes remained in the aquatic environment throughout their life and were most likely not capable of effective terrestrial locomotion. The frequency distribution of the two phenotypes in modern salamander populations and the environmental cues that influence the development of them provide a comparative framework for the discussion of the evolution of the two life history pathways in branchiosaurids. doi:10.1002/mmng.200800012

  16. Signalling pathways involved in adult heart formation revealed by gene expression profiling in Drosophila.

    Directory of Open Access Journals (Sweden)

    Bruno Zeitouni

    2007-10-01

    Full Text Available Drosophila provides a powerful system for defining the complex genetic programs that drive organogenesis. Under control of the steroid hormone ecdysone, the adult heart in Drosophila forms during metamorphosis by a remodelling of the larval cardiac organ. Here, we evaluated the extent to which transcriptional signatures revealed by genomic approaches can provide new insights into the molecular pathways that underlie heart organogenesis. Whole-genome expression profiling at eight successive time-points covering adult heart formation revealed a highly dynamic temporal map of gene expression through 13 transcript clusters with distinct expression kinetics. A functional atlas of the transcriptome profile strikingly points to the genomic transcriptional response of the ecdysone cascade, and a sharp regulation of key components belonging to a few evolutionarily conserved signalling pathways. A reverse genetic analysis provided evidence that these specific signalling pathways are involved in discrete steps of adult heart formation. In particular, the Wnt signalling pathway is shown to participate in inflow tract and cardiomyocyte differentiation, while activation of the PDGF-VEGF pathway is required for cardiac valve formation. Thus, a detailed temporal map of gene expression can reveal signalling pathways responsible for specific developmental programs and provides here substantial grasp into heart formation.

  17. Anopheline larval habitats seasonality and species distribution: a prerequisite for effective targeted larval habitats control programmes.

    Directory of Open Access Journals (Sweden)

    Eliningaya J Kweka

    Full Text Available Larval control is of paramount importance in the reduction of malaria vector abundance and subsequent disease transmission reduction. Understanding larval habitat succession and its ecology in different land use managements and cropping systems can give an insight for effective larval source management practices. This study investigated larval habitat succession and ecological parameters which influence larval abundance in malaria epidemic prone areas of western Kenya.A total of 51 aquatic habitats positive for anopheline larvae were surveyed and visited once a week for a period of 85 weeks in succession. Habitats were selected and identified. Mosquito larval species, physico-chemical parameters, habitat size, grass cover, crop cycle and distance to nearest house were recorded. Polymerase chain reaction revealed that An. gambiae s.l was the most dominant vector species comprised of An.gambiae s.s (77.60% and An.arabiensis (18.34%, the remaining 4.06% had no amplification by polymerase chain reaction. Physico-chemical parameters and habitat size significantly influenced abundance of An. gambiae s.s (P = 0.024 and An. arabiensis (P = 0.002 larvae. Further, larval species abundance was influenced by crop cycle (P≤0.001, grass cover (P≤0.001, while distance to nearest houses significantly influenced the abundance of mosquito species larvae (r = 0.920;P≤0.001. The number of predator species influenced mosquito larval abundance in different habitat types. Crop weeding significantly influenced with the abundance of An.gambiae s.l (P≤0.001 when preceded with fertilizer application. Significantly higher anopheline larval abundance was recorded in habitats in pasture compared to farmland (P = 0.002. When habitat stability and habitat types were considered, hoof print were the most productive followed by disused goldmines.These findings suggest that implementation of effective larval control programme should be targeted with larval

  18. Olfactory memories are intensity specific in larval Drosophila.

    Science.gov (United States)

    Mishra, Dushyant; Chen, Yi-Chun; Yarali, Ayse; Oguz, Tuba; Gerber, Bertram

    2013-05-01

    Learning can rely on stimulus quality, stimulus intensity, or a combination of these. Regarding olfaction, the coding of odour quality is often proposed to be combinatorial along the olfactory pathway, and working hypotheses are available concerning short-term associative memory trace formation of odour quality. However, it is less clear how odour intensity is coded, and whether olfactory memory traces include information about the intensity of the learnt odour. Using odour-sugar associative conditioning in larval Drosophila, we first describe the dose-effect curves of learnability across odour intensities for four different odours (n-amyl acetate, 3-octanol, 1-octen-3-ol and benzaldehyde). We then chose odour intensities such that larvae were trained at an intermediate odour intensity, but were tested for retention with either that trained intermediate odour intensity, or with respectively higher or lower intensities. We observed a specificity of retention for the trained intensity for all four odours used. This adds to the appreciation of the richness in 'content' of olfactory short-term memory traces, even in a system as simple as larval Drosophila, and to define the demands on computational models of associative olfactory memory trace formation. We suggest two kinds of circuit architecture that have the potential to accommodate intensity learning, and discuss how they may be implemented in the insect brain.

  19. Rehydration of forensically important larval Diptera specimens.

    Science.gov (United States)

    Sanford, Michelle R; Pechal, Jennifer L; Tomberlin, Jeffery K

    2011-01-01

    Established procedures for collecting and preserving evidence are essential for all forensic disciplines to be accepted in court and by the forensic community at large. Entomological evidence, such as Diptera larvae, are primarily preserved in ethanol, which can evaporate over time, resulting in the dehydration of specimens. In this study, methods used for rehydrating specimens were compared. The changes in larval specimens with respect to larval length and weight for three forensically important blow fly (Diptera: Calliphoridae) species in North America were quantified. Phormia regina (Meigen), Cochliomyia macellaria (F.), and Chrysomya rufifacies (Macquart) third-instar larvae were collected from various decomposing animals and preserved with three preservation methods (80% ethanol, 70% isopropyl alcohol, and hot-water kill then 80% ethanol). Preservative solutions were allowed to evaporate. Rehydration was attempted with either of the following: 80% ethanol, commercial trisodium phosphate substitute solution, or 0.5% trisodium phosphate solution. All three methods partially restored weight and length of specimens recorded before preservation. Analysis of variance results indicated that effects of preservation, rehydration treatment, and collection animal were different in each species. The interaction between preservative method and rehydration treatment had a significant effect on both P. regina and C. macellaria larval length and weight. In addition, there was a significant interaction effect of collection animal on larval C. macellaria measurements. No significant effect was observed in C. rufifacies larval length or weight among the preservatives or treatments. These methods could be used to establish a standard operating procedure for dealing with dehydrated larval specimens in forensic investigations.

  20. Longitudinal Magnetic Resonance Imaging (MRI) Analysis of the Developmental Changes of Tourette Syndrome Reveal Reduced Diffusion in the Cortico-Striato-Thalamo-Cortical Pathways

    DEFF Research Database (Denmark)

    Debes, Nanette; Jeppesen, Signe; Raghava, Jayachandra Mitta

    2015-01-01

    There is evidence that cortico-striato-thalamo-cortical pathways are involved in Tourette syndrome. We performed a longitudinal imaging study in 22 patients and 21 healthy controls in order to examine the development of tics and its correlation with magnetic resonance imaging (MRI) findings....... Patients were divided in a group with persisting and a group with remission of tics. We found a decrease in volume of left putamen in controls, but not in patients. We found changes in mean diffusivity between patients and controls in right caudate nucleus, thalamus, and frontal lobe. In contrast...... to controls, parallel and perpendicular diffusivity decreased in patients and were most pronounced in the patients with persisting tics compared to those with remission. The findings suggest that the development of the brain in patients with remission resembles the normal development more than in patients...

  1. Developmental Scaffolding

    DEFF Research Database (Denmark)

    Giorgi, Franco; Bruni, Luis Emilio

    2015-01-01

    . Within the developmental hierarchy, each module yields an inter-level relationship that makes it possible for the scaffolding to mediate the production of selectable variations. Awide range of genetic, cellular and morphological mechanisms allows the scaffolding to integrate these modular variations...... to the complexity of sign recognition proper of a cellular community. In this semiotic perspective, the apparent goal directness of any developmental strategy should no longer be accounted for by a predetermined genetic program, but by the gradual definition of the relationships selected amongst the ones...

  2. Soundscapes and Larval Settlement: Characterizing the Stimulus from a Larval Perspective.

    Science.gov (United States)

    Lillis, Ashlee; Eggleston, David B; Bohnenstiehl, DelWayne R

    2016-01-01

    There is growing evidence that underwater sounds serve as a cue for the larvae of marine organisms to locate suitable settlement habitats; however, the relevant spatiotemporal scales of variability in habitat-related sounds and how this variation scales with larval settlement processes remain largely uncharacterized, particularly in estuarine habitats. Here, we provide an overview of the approaches we have developed to characterize an estuarine soundscape as it relates to larval processes, and a conceptual framework is provided for how habitat-related sounds may influence larval settlement, using oyster reef soundscapes as an example.

  3. Genetic diversity, classification and comparative study on the larval ...

    African Journals Online (AJOL)

    Genetic diversity, classification and comparative study on the larval phenotypic ... B. mori showed different performance based on larval phenotypic data. The analysis of variance regarding the studied traits showed that different strains have ...

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

    Directory of Open Access Journals (Sweden)

    Ori Segev

    Full Text Available 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.

  5. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.

    Science.gov (United States)

    Liu, Yingying; Li, Fengna; Kong, Xiangfeng; Tan, Bie; Li, Yinghui; Duan, Yehui; Blachier, François; Hu, Chien-An A; Yin, Yulong

    2015-01-01

    Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA) pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet)- or higher/NRC (National Research Council)-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I) and longissimus dorsi muscle (LDM, type II) were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR) signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (Prelated AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05) than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K), and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05). There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05) the levels for mTOR and p70S6K in Bama mini-pigs, but repressed (P<0.05) the level for p70S6K in Landrace pigs. The higher protein-NRC diet increased ratio of p-mTOR/mTOR in

  6. DEVELOPMENTAL TAXONOMY OF CONDUCT DISORDER

    Directory of Open Access Journals (Sweden)

    Jelena Kostić

    2015-12-01

    Full Text Available Conduct disorder is a heterogeneous disorder in terms of etiology, course and prognosis, and currently, there is no singular model that would describe the development of the disorder. The results of empirical research on males confirm this heterogeneity, as they point out to two possible developmental pathways: childhood-onset and adolescentonset type. This paper presents the basic elements of developmental taxonomic theory which argues that there are two different developmental pathways to conduct disorder which have different causes and serve as the basis for the current typology of conduct disorders in the classification systems. Such a typology of conduct disorders in the diagnostic classification allows better understanding, prognosis and choice of treatment.

  7. Developmental delay

    Science.gov (United States)

    Nutrition support is essential for the care of the child with developmental delay. After a thorough evaluation, an individualized intervention plan that accounts for the child’s nutrition status, feeding ability, and medical condition may be determined. Nutrition assessments may be performed at leas...

  8. Developmental Work

    DEFF Research Database (Denmark)

    Møller, Niels; Hvid, Helge; Kristensen, Tage Søndergaard

    2003-01-01

    Human Deveoplment and Working Life - Work for Welfare explores whether the development of human resources at company level can improve individuals' quality of life, companies' possibilities of development, and welfare and democracy in society. Chapter two discuss the concept "developmental work...

  9. Asymmetric larval head and mandibles of Hydrophilus acuminatus (Insecta: Coleoptera, Hydrophilidae): Fine structure and embryonic development.

    Science.gov (United States)

    Sato, Shun'ichi; Inoda, Toshio; Niitsu, Shuhei; Kubota, Souichirou; Goto, Yuji; Kobayashi, Yukimasa

    2017-11-01

    The larvae of a water scavenger beetle, Hydrophilus acuminatus, have strongly asymmetric mandibles; the right one is long and slender, whereas the left one is short and stout. The fine structure and embryonic development of the head capsule and mandibles of this species were examined using light and scanning electron microscopy, and asymmetries in shape were detected in these structures applying an elliptic Fourier analysis. The larval mandibles are asymmetric in the following aspects: whole length, the number, structure and arrangement of retinacula (inner teeth), and size and shape of both the molar and incisor regions. The larval head is also asymmetric; the left half of the head capsule is larger than the right, and the left adductor muscle of the mandible is much thicker than the right. The origin and developmental process of asymmetric mandibles were traced in developing embryos whose developmental period is about 270 h and divided into 10 stages. Mandibular asymmetries are produced by the cumulative effects of six stepwise modifications that occur from about 36% of the total developmental time onward. The significance of these modifications was discussed with respect to the functional advantages of asymmetries and the phylogeny of members of the Hydrophilidae. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Developmental control of cell division

    NARCIS (Netherlands)

    Boxem, M. (Mike)

    2002-01-01

    During development of multicellular organisms, cell divisions need to be coordinated with the developmental program of the entire organism. Although the mechanisms that drive cells through the division cycle are well understood, very little is known about the pathways that link extracellular signals

  11. Biophysical models of larval dispersal in the Benguela Current ...

    African Journals Online (AJOL)

    We synthesise and update results from the suite of biophysical, larval-dispersal models developed in the Benguela Current ecosystem. Biophysical models of larval dispersal use outputs of physical hydrodynamic models as inputs to individual-based models in which biological processes acting during the larval life are ...

  12. Cultural pathways through universal development.

    Science.gov (United States)

    Greenfield, Patricia M; Keller, Heidi; Fuligni, Andrew; Maynard, Ashley

    2003-01-01

    We focus our review on three universal tasks of human development: relationship formation, knowledge acquisition, and the balance between autonomy and relatedness at adolescence. We present evidence that each task can be addressed through two deeply different cultural pathways through development: the pathways of independence and interdependence. Whereas core theories in developmental psychology are universalistic in their intentions, they in fact presuppose the independent pathway of development. Because the independent pathway is therefore well-known in psychology, we focus a large part of our review on empirically documenting the alternative, interdependent pathway for each developmental task. We also present three theoretical approaches to culture and development: the ecocultural, the sociohistorical, and the cultural values approach. We argue that an understanding of cultural pathways through human development requires all three approaches. We review evidence linking values (cultural values approach), ecological conditions (ecocultural approach), and socialization practices (sociohistorical approach) to cultural pathways through universal developmental tasks.

  13. Application of radioisotope tracer techniques in studies on host-parasite relationships, with special reference to larval trematodes. A review

    International Nuclear Information System (INIS)

    Christensen, N.Oe.

    1981-01-01

    The application of radioisotope tracer techniques in studies on various host-parasite relationships between larval trematodes and their intermediate and definite hosts is reviewed. Such studies comprise, for example, the reproduction and nutrition of various developmental stages of trematodes in relation to host and environment. The preparation and application of radiolabelled larvae are also discussed with special emphasis on their use in studies on free-living ecology and migration in hosts. (author)

  14. Signaling Pathways Related to Protein Synthesis and Amino Acid Concentration in Pig Skeletal Muscles Depend on the Dietary Protein Level, Genotype and Developmental Stages.

    Directory of Open Access Journals (Sweden)

    Yingying Liu

    Full Text Available Muscle growth is regulated by the homeostatic balance of the biosynthesis and degradation of muscle proteins. To elucidate the molecular interactions among diet, pig genotype, and physiological stage, we examined the effect of dietary protein concentration, pig genotype, and physiological stages on amino acid (AA pools, protein deposition, and related signaling pathways in different types of skeletal muscles. The study used 48 Landrace pigs and 48 pure-bred Bama mini-pigs assigned to each of 2 dietary treatments: lower/GB (Chinese conventional diet- or higher/NRC (National Research Council-protein diet. Diets were fed from 5 weeks of age to respective market weights of each genotype. Samples of biceps femoris muscle (BFM, type I and longissimus dorsi muscle (LDM, type II were collected at nursery, growing, and finishing phases according to the physiological stage of each genotype, to determine the AA concentrations, mRNA levels for growth-related genes in muscles, and protein abundances of mechanistic target of rapamycin (mTOR signaling pathway. Our data showed that the concentrations of most AAs in LDM and BFM of pigs increased (P<0.05 gradually with increasing age. Bama mini-pigs had generally higher (P<0.05 muscle concentrations of flavor-related AA, including Met, Phe, Tyr, Pro, and Ser, compared with Landrace pigs. The mRNA levels for myogenic determining factor, myogenin, myocyte-specific enhancer binding factor 2 A, and myostatin of Bama mini-pigs were higher (P<0.05 than those of Landrace pigs, while total and phosphorylated protein levels for protein kinase B, mTOR, and p70 ribosomal protein S6 kinases (p70S6K, and ratios of p-mTOR/mTOR, p-AKT/AKT, and p-p70S6K/p70S6K were lower (P<0.05. There was a significant pig genotype-dependent effect of dietary protein on the levels for mTOR and p70S6K. When compared with the higher protein-NRC diet, the lower protein-GB diet increased (P<0.05 the levels for mTOR and p70S6K in Bama mini-pigs, but

  15. Larval morphology of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) using scanning electron microscopy.

    Science.gov (United States)

    Sukontason, Kabkaew L; Sukontason, Kom; Piangjai, Somsak; Boonchu, Noppawan; Chaiwong, Tarinee; Vogtsberger, Roy C; Kuntalue, Budsabong; Thijuk, Natchanart; Olson, Jimmy K

    2003-06-01

    The larval morphology of Chrysomya megacephala (Fabricius) is presented using scanning electron microscopy (SEM). Extreme similarity of this species to Chrysomya rufifacies (Macquart), a species usually found concurrently inhabiting decomposing human corpses in Thailand, is seen only in the first-instar larvae. The relative thickness of the branches of the posterior spiracular hairs in these species could be used to differentiate them in this developmental stage. In contrast, the "hairy" appearance of C. rufifacies allows second- and third-instar larvae to be easily distinguished. Results of this study should help in future endeavors to differentiate C. megacephala from other larvae found in decomposing human corpses in Thailand.

  16. Depletion of juvenile hormone esterase extends larval growth in Bombyx mori.

    Science.gov (United States)

    Zhang, Zhongjie; Liu, Xiaojing; Shiotsuki, Takahiro; Wang, Zhisheng; Xu, Xia; Huang, Yongping; Li, Muwang; Li, Kai; Tan, Anjiang

    2017-02-01

    Two major hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), regulate insect growth and development according to their precisely coordinated titres, which are controlled by both biosynthesis and degradation pathways. Juvenile hormone esterase (JHE) is the primary JH-specific degradation enzyme that plays a key role in regulating JH titers, along with JH epoxide hydrolase (JHEH) and JH diol kinase (JHDK). In the current study, a loss-of-function analysis of JHE in the silkworm, Bombyx mori, was performed by targeted gene disruption using the transgenic CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases) system. Depletion of B. mori JHE (BmJHE) resulted in the extension of larval stages, especially the penultimate and ultimate larval stages, without deleterious effects to silkworm physiology. The expression of JHEH and JHDK was upregulated in mutant animals, indicating the existence of complementary routes in the JH metabolism pathway in which inactivation of one enzyme will activate other enzymes. RNA-Seq analysis of mutant animals revealed that genes involved in protein processing in the endoplasmic reticulum and in amino acid metabolism were affected by BmJHE depletion. Depletion of JHE and subsequent delayed JH metabolism activated genes in the TOR pathway, which are ultimately responsible for extending larval growth. The transgenic Cas9 system used in the current study provides a promising approach for analysing the actions of JH, especially in nondrosophilid insects. Furthermore, prolonging larval stages produced larger larvae and cocoons, which is greatly beneficial to silk production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. In Vitro Anti-Echinococcal and Metabolic Effects of Metformin Involve Activation of AMP-Activated Protein Kinase in Larval Stages of Echinococcus granulosus

    Science.gov (United States)

    Loos, Julia A.; Cumino, Andrea C.

    2015-01-01

    Metformin (Met) is a biguanide anti-hyperglycemic agent, which also exerts antiproliferative effects on cancer cells. This drug inhibits the complex I of the mitochondrial electron transport chain inducing a fall in the cell energy charge and leading 5'-AMP-activated protein kinase (AMPK) activation. AMPK is a highly conserved heterotrimeric complex that coordinates metabolic and growth pathways in order to maintain energy homeostasis and cell survival, mainly under nutritional stress conditions, in a Liver Kinase B1 (LKB1)-dependent manner. This work describes for the first time, the in vitro anti-echinococcal effect of Met on Echinococcus granulosus larval stages, as well as the molecular characterization of AMPK (Eg-AMPK) in this parasite of clinical importance. The drug exerted a dose-dependent effect on the viability of both larval stages. Based on this, we proceeded with the identification of the genes encoding for the different subunits of Eg-AMPK. We cloned one gene coding for the catalytic subunit (Eg-ampkɑ) and two genes coding for the regulatory subunits (Eg-ampkβ and Eg-ampkγ), all of them constitutively transcribed in E. granulosus protoscoleces and metacestodes. Their deduced amino acid sequences show all the conserved functional domains, including key amino acids involved in catalytic activity and protein-protein interactions. In protoscoleces, the drug induced the activation of AMPK (Eg-AMPKɑ-P176), possibly as a consequence of cellular energy charge depletion evidenced by assays with the fluorescent indicator JC-1. Met also led to carbohydrate starvation, it increased glucogenolysis and homolactic fermentation, and decreased transcription of intermediary metabolism genes. By in toto immunolocalization assays, we detected Eg-AMPKɑ-P176 expression, both in the nucleus and the cytoplasm of cells as in the larval tegument, the posterior bladder and the calcareous corpuscles of control and Met-treated protoscoleces. Interestingly, expression of Eg

  18. Developmental Deltamethrin Exposure Causes Persistent Changes in Dopaminergic Gene Expression, Neurochemistry, and Locomotor Activity in Zebrafish.

    Science.gov (United States)

    Kung, Tiffany S; Richardson, Jason R; Cooper, Keith R; White, Lori A

    2015-08-01

    Pyrethroids are commonly used insecticides that are considered to pose little risk to human health. However, there is an increasing concern that children are more susceptible to the adverse effects of pesticides. We used the zebrafish model to test the hypothesis that developmental exposure to low doses of the pyrethroid deltamethrin results in persistent alterations in dopaminergic gene expression, neurochemistry, and locomotor activity. Zebrafish embryos were treated with deltamethrin (0.25-0.50 μg/l), at concentrations below the LOAEL, during the embryonic period [3-72 h postfertilization (hpf)], after which transferred to fresh water until the larval stage (2-weeks postfertilization). Deltamethrin exposure resulted in decreased transcript levels of the D1 dopamine (DA) receptor (drd1) and increased levels of tyrosine hydroxylase at 72 hpf. The reduction in drd1 transcripts persisted to the larval stage and was associated with decreased D2 dopamine receptor transcripts. Larval fish, exposed developmentally to deltamethrin, had increased levels of homovanillic acid, a DA metabolite. Since the DA system is involved in locomotor activity, we measured the swim activity of larval fish following a transition to darkness. Developmental exposure to deltamethrin significantly increased larval swim activity which was attenuated by concomitant knockdown of the DA transporter. Acute exposure to methylphenidate, a DA transporter inhibitor, increased swim activity in control larva, while reducing swim activity in larva developmentally exposed to deltamethrin. Developmental exposure to deltamethrin causes locomotor deficits in larval zebrafish, which is likely mediated by dopaminergic dysfunction. This highlights the need to understand the persistent effects of low-dose neurotoxicant exposure during development. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Flexible responses to visual and olfactory stimuli by foraging Manduca sexta: larval nutrition affects adult behaviour.

    Science.gov (United States)

    Goyret, Joaquín; Kelber, Almut; Pfaff, Michael; Raguso, Robert A

    2009-08-07

    Here, we show that the consequences of deficient micronutrient (beta-carotene) intake during larval stages of Manduca sexta are carried across metamorphosis, affecting adult behaviour. Our manipulation of larval diet allowed us to examine how developmental plasticity impacts the interplay between visual and olfactory inputs on adult foraging behaviour. Larvae of M. sexta were reared on natural (Nicotiana tabacum) and artificial laboratory diets containing different concentrations of beta-carotene (standard diet, low beta-carotene, high beta-carotene and cornmeal). This vitamin-A precursor has been shown to be crucial for photoreception sensitivity in the retina of M. sexta. After completing development, post-metamorphosis, starved adults were presented with artificial feeders that could be either scented or unscented. Regardless of their larval diet, adult moths fed with relatively high probabilities on scented feeders. When feeders were unscented, moths reared on tobacco were more responsive than moths reared on beta-carotene-deficient artificial diets. Strikingly, moths reared on artificial diets supplemented with increasing amounts of beta-carotene (low beta and high beta) showed increasing probabilities of response to scentless feeders. We discuss these results in relationship to the use of complex, multi-modal sensory information by foraging animals.

  20. Effects of fenoxycarb exposure on complete larval development of the xanthid crab, Rhithropanopeus harrisii

    International Nuclear Information System (INIS)

    Cripe, G.M.; McKenney, C.L.; Hoglund, M.D.; Harris, P.S.

    2003-01-01

    The pest control agent fenoxycarb reduced survival and extended duration of developing larval stages in the xanthid crab, Rhithropanopeus harrisii. - Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 μg fenoxycarb/l and in megalopae exposed to 48 μg fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments ≥48 μg/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to ≥48 μg/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary

  1. Effects of fenoxycarb exposure on complete larval development of the xanthid crab, Rhithropanopeus harrisii

    Energy Technology Data Exchange (ETDEWEB)

    Cripe, G.M.; McKenney, C.L.; Hoglund, M.D.; Harris, P.S

    2003-09-01

    The pest control agent fenoxycarb reduced survival and extended duration of developing larval stages in the xanthid crab, Rhithropanopeus harrisii. - Pest control agents, such as juvenile hormone analogues (JHA), have been developed to limit effects on non-target organisms that co-inhabit insect pest habitats. Rhithropanopeus harrisii, an estuarine xanthid crab, was used to observe the impacts of the JHA, fenoxycarb, on the pattern of complete larval development as well as survival of larvae and successful metamorphosis to first crab stage. Significant mortality occurred in the first of four zoeal stages (after 2-3 days of exposure) at the highest treatment of 240 {mu}g fenoxycarb/l and in megalopae exposed to 48 {mu}g fenoxycarb/l. The time required to metamorphose to the first crab stage was significantly increased for megalopae in all treatments {>=}48 {mu}g/l. This delay in development was sufficient to significantly prolong the entire developmental period from zoea to crabs. Unexposed larvae developed to crabs in an average of 16 days; larvae exposed to {>=}48 {mu}g/l required 19-20 days. Reduced survival and extended duration of developing larval stages in the life history of a benthic invertebrate may alter the population dynamics of these organisms in the estuary.

  2. Larval competition of Chrysomya megacephala and Chrysomya rufifacies (Diptera: Calliphoridae): behavior and ecological studies of two blow fly species of forensic significance.

    Science.gov (United States)

    Shiao, Shiuh-Feng; Yeh, Ta-Chuan

    2008-07-01

    previous studies, and we suspect that the difference was partially caused by different experimental designs and different biological characters of different blow fly colonies. Our results also suggest that both the predation ability and defense or escape activity should be taken into account when evaluating larval competitive advantages. The durations of larval stages of these two species could be decreased by approximately 54 h when a single species was reared alone and food was limited; the largest reduction in larval duration, approximately 25 h in C. megacephala and 34 h in C. rufifacies, caused by interspecific competition was under a high larval density. In conclusion, competition decreased the larval duration of these two species by up to 2 d; this also draws attention to justifying the postmortem interval estimation of using larval developmental data when larval competition exists.

  3. The role of dopamine in Drosophila larval classical olfactory conditioning.

    Directory of Open Access Journals (Sweden)

    Mareike Selcho

    Full Text Available Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt as well as appetitive (odor-sugar associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive

  4. Transcriptome and quantitative proteome analysis reveals molecular processes associated with larval metamorphosis in the polychaete pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Sun, Jin; Mok, FloraSy; Liu, Lingli; Qiu, Jianwen; Ravasi, Timothy; Qian, Peiyuan

    2013-01-01

    Larval growth of the polychaete worm Pseudopolydora vexillosa involves the formation of segment-specific structures. When larvae attain competency to settle, they discard swimming chaetae and secrete mucus. The larvae build tubes around themselves and metamorphose into benthic juveniles. Understanding the molecular processes, which regulate this complex and unique transition, remains a major challenge because of the limited molecular information available. To improve this situation, we conducted high-throughput RNA sequencing and quantitative proteome analysis of the larval stages of P. vexillosa. Based on gene ontology (GO) analysis, transcripts related to cellular and metabolic processes, binding, and catalytic activities were highly represented during larval-adult transition. Mitogen-activated protein kinase (MAPK), calcium-signaling, Wnt/β-catenin, and notch signaling metabolic pathways were enriched in transcriptome data. Quantitative proteomics identified 107 differentially expressed proteins in three distinct larval stages. Fourteen and 53 proteins exhibited specific differential expression during competency and metamorphosis, respectively. Dramatic up-regulation of proteins involved in signaling, metabolism, and cytoskeleton functions were found during the larval-juvenile transition. Several proteins involved in cell signaling, cytoskeleton and metabolism were up-regulated, whereas proteins related to transcription and oxidative phosphorylation were down-regulated during competency. The integration of high-throughput RNA sequencing and quantitative proteomics allowed a global scale analysis of larval transcripts/proteins associated molecular processes in the metamorphosis of polychaete worms. Further, transcriptomic and proteomic insights provide a new direction to understand the fundamental mechanisms that regulate larval metamorphosis in polychaetes. © 2013 American Chemical Society.

  5. Transcriptome and quantitative proteome analysis reveals molecular processes associated with larval metamorphosis in the polychaete pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2013-03-01

    Larval growth of the polychaete worm Pseudopolydora vexillosa involves the formation of segment-specific structures. When larvae attain competency to settle, they discard swimming chaetae and secrete mucus. The larvae build tubes around themselves and metamorphose into benthic juveniles. Understanding the molecular processes, which regulate this complex and unique transition, remains a major challenge because of the limited molecular information available. To improve this situation, we conducted high-throughput RNA sequencing and quantitative proteome analysis of the larval stages of P. vexillosa. Based on gene ontology (GO) analysis, transcripts related to cellular and metabolic processes, binding, and catalytic activities were highly represented during larval-adult transition. Mitogen-activated protein kinase (MAPK), calcium-signaling, Wnt/β-catenin, and notch signaling metabolic pathways were enriched in transcriptome data. Quantitative proteomics identified 107 differentially expressed proteins in three distinct larval stages. Fourteen and 53 proteins exhibited specific differential expression during competency and metamorphosis, respectively. Dramatic up-regulation of proteins involved in signaling, metabolism, and cytoskeleton functions were found during the larval-juvenile transition. Several proteins involved in cell signaling, cytoskeleton and metabolism were up-regulated, whereas proteins related to transcription and oxidative phosphorylation were down-regulated during competency. The integration of high-throughput RNA sequencing and quantitative proteomics allowed a global scale analysis of larval transcripts/proteins associated molecular processes in the metamorphosis of polychaete worms. Further, transcriptomic and proteomic insights provide a new direction to understand the fundamental mechanisms that regulate larval metamorphosis in polychaetes. © 2013 American Chemical Society.

  6. Diverse Pathways in Children's Learning.

    Science.gov (United States)

    Lambert, Beverley

    1996-01-01

    Used a Partially Ordered Scaling of Items method to analyze block construction play in a replication of Innes and King-Shaw's 1985 study. Found several developmental pathways for block play, illustrating the web-like nature of conceptual development. Results suggest a contextual developmental approach to better acknowledge individual diversity in…

  7. Granulomatous responses in larval taeniid infections.

    Science.gov (United States)

    Díaz, Á; Sagasti, C; Casaravilla, C

    2018-05-01

    Granulomas are responses to persistent nonliving bodies or pathogens, centrally featuring specialized macrophage forms called epithelioid and multinucleated giant cells. The larval stages of the cestode parasites of the Taeniidae family (Taenia, Echinococcus) develop for years in fixed tissue sites in mammals. In consequence, they are targets of granulomatous responses. The information on tissue responses to larval taeniids is fragmented among host and parasite species and scattered over many decades. We attempt to draw an integrated picture of these responses in solid tissues. The intensity of inflammation around live parasites spans a spectrum from minimal to high, parasite vitality correlating with low inflammation. The low end of the inflammatory spectrum features collagen capsules proximal to the parasites and moderate distal infiltration. The middle of the spectrum is dominated by classical granulomatous responses, whereas the high end features massive eosinophil invasions. Across the range of parasite species, much observational evidence suggests that eosinophils are highly effective at killing larval taeniids in solid tissues, before and during chronic granulomatous responses. The evidence available also suggests that these parasites are adapted to inhibit host granulomatous responses, in part through the exacerbation of host regulatory mechanisms including regulatory T cells and TGF-β. © 2018 John Wiley & Sons Ltd.

  8. Linking larval history to juvenile demography in the bicolor damselfish Stegastes partitus (Perciformes:Pomacentridae

    Directory of Open Access Journals (Sweden)

    Richard S Nemeth

    2005-05-01

    Full Text Available Otolith-based reconstructions of daily larval growth increments were used to examine the effect of variation in larval growth on size and age at settlement and post-settlement growth,survival and habitat preferences of juvenile bicolor damselfish (Stegastes partitus Poey.During August 1992 and 1994,newly settled S. partitus were collected from Montastraea coral heads and Porites rubble piles in Tague Bay,St.Croix,U.S. Virgin Islands (17 °45 ’ N,64 °42 ’ W.Daily lapillar otolith increments from each fish were counted and measured with Optimas image analysis software.S.partitus pelagic larval duration was 23.7 d in 1992 (n =70and 24.6 d in 1994 (n =38and larval age at settlement averaged 13.0 mm total length both years.Analysis of daily otolith increments demonstrated that variation in larval growth rates and size and age at settlement had no detectable effect on post-settlement survivorship but that larger larvae showed a preference for Montastraea coral at settlement.Late larval and early juvenile growth rates showed a significant positive relationship indicating that growth patterns established during the planktonic stage can span metamorphosis and continue into the benthic juvenile phase.Larval growth rates during the first two weeks post-hatching also had a strong effect on age to developmental competence (ability to undergo metamorphosisin both 1992 and 1994 with the fastest growing larvae being 8 d younger and 0.8 mm smaller at settlement than the slowest growing larvae.These differential growth rates in early stage larvae established trajectories toward larval developmental competence and may prove important in biogeographical studies of larval dispersal.Reconstruyendo aumentos diarios de otolitos se compará la variación en crecimiento larval sobre el tamaño y la edad de asentamiento,y el crecimiento post-acentamiento, sobrevivencia y preferencia de hábitat,del pez damisela bicolor (Stegastes partitus Poeyjoven.En agosto de 1992

  9. dbl-1/TGF-β and daf-12/NHR Signaling Mediate Cell-Nonautonomous Effects of daf-16/FOXO on Starvation-Induced Developmental Arrest.

    Directory of Open Access Journals (Sweden)

    Rebecca E W Kaplan

    2015-12-01

    , this study shows that daf-16/FOXO promotes developmental arrest cell-nonautonomously by repressing pathways that promote larval development.

  10. dbl-1/TGF-β and daf-12/NHR Signaling Mediate Cell-Nonautonomous Effects of daf-16/FOXO on Starvation-Induced Developmental Arrest.

    Science.gov (United States)

    Kaplan, Rebecca E W; Chen, Yutao; Moore, Brad T; Jordan, James M; Maxwell, Colin S; Schindler, Adam J; Baugh, L Ryan

    2015-12-01

    that daf-16/FOXO promotes developmental arrest cell-nonautonomously by repressing pathways that promote larval development.

  11. Impacts of Silver Nanoparticle Ingestion on Pigmentation and Developmental Progression in Drosophila

    Directory of Open Access Journals (Sweden)

    S. Catherine Silver Key

    2011-10-01

    Full Text Available In recent years, the advent of nanomaterial use has increased exposure rates and raised health concerns. However, the toxicology profiles of many nanomaterials are far from complete for various reasons. In this study, Drosophila melanogaster, commonly called fruit flies, were exposed to one of the most widely used nanomaterials, silver nanopowder (Ag NP, to assess its toxicity and determine if D. melanogaster would be a good model organism for nanotoxicology studies. Comparison of developmental progression amongst groups of flies ingesting different Ag NP concentrations (0.05%/~90 ppm-5.0%/~9000 ppm, revealed that hatch rates were unaffected, but that larval progression was impeded at any dosage of Ag NP. At 0.3% Ag NP an approximate LD50 was observed. Additionally, a distinctive phenotype was observed among emergent adults (F1 generation that arose from larvae exposed to Ag NP which included reduced body pigmentation accompanied by shortened life span and abnormal climbing behavior. The phenotype prompted speculation that Ag NPs may affect the dopamine and/or the stress response pathway(s.

  12. Drivers of larval fish assemblage shift during the spring-summer transition in the coastal Mediterranean

    Science.gov (United States)

    Álvarez, Itziar; Catalán, Ignacio A.; Jordi, Antoni; Palmer, Miquel; Sabatés, Ana; Basterretxea, Gotzon

    2012-01-01

    The influence of coastal environmental conditions from winter-spring to summer on fish larvae assemblages in a temperate area has suggested a seasonal shift in ecosystem-level variation through which trophic pathways shift from the pelagic to the benthic system. This variation may be related to marked effects in the reproductive strategies in the fishes inhabiting the area and indirectly affect ichthyoplankton assemblages. Larval fish assemblages were sampled fortnightly at three stations located in coastal waters off southern Mallorca (Western Mediterranean) from March to August 2007, covering the main spawning period for the resident coastal fish in this region. The larval fish assemblage showed clear seasonality with higher specific abundance but lower diversity in the spring. Two main assemblages were identified: a spring assemblage, occurring at surface seawater temperatures ichthyoplankton communities occurred in early June, coinciding with the onset of summer hydrographical conditions and the local benthic productivity peak.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Prostaglandin-mediated recovery from bacteremia delays larval development in fall armyworm, Spodoptera frugiperda.

    Science.gov (United States)

    Zhang, Lei; Ringbauer, Joseph A; Goodman, Cynthia L; Reall, Tamra; Jiang, Xing-Fu; Stanley, David

    2018-04-01

    Insect immunity includes a surveillance system that detects and signals infections, coupled with hemocytic and humoral immune functions. These functions are signaled and coordinated by several biochemicals, including biogenic amines, insect cytokines, peptides, and prostaglandins (PGs). The actions of these mediators are coordinated within cells by various forms of cross-talk among the signaling systems and they result in effective reactions to infection. While this is well understood, we lack information on how immune-mediated recovery influences subsequent juvenile development in surviving insects. We investigated this point by posing the hypothesis that PG signaling is necessary for larval recovery, although the recovery imposes biological costs, registered in developmental delays and failures in surviving individuals. Here, we report that nodulation responses to infections by the bacterium, Serratia marcescens, increased over time up to 5 h postinfection, with no further nodulation; it increased in a linear manner with increasing bacterial dosages. Larval survivorship decreased with increasing bacterial doses. Treating larvae with the PG-biosynthesis inhibitor, indomethacin, led to sharply decreased nodulation reactions to infection, which were rescued in larvae cotreated with indomethacin and the PG-precursor, arachidonic acid. Although nodulation was fully rescued, all bacterial challenged larvae suffered reduced survivorship compared to controls. Bacterial infection led to reduced developmental rates in larvae, but not pupae. Adult emergence from pupae that developed from experimental larvae was also decreased. Taken together, our data potently bolster our hypothesis. © 2018 Wiley Periodicals, Inc.

  15. Embryo-larval exposure to atrazine reduces viability and alters oxidative stress parameters in Drosophila melanogaster.

    Science.gov (United States)

    Figueira, Fernanda Hernandes; Aguiar, Lais Mattos de; Rosa, Carlos Eduardo da

    2017-01-01

    The herbicide atrazine has been used worldwide with subsequent residual contamination of water and food, which may cause adverse effects on non-target organisms. Animal exposure to this herbicide may affect development, reproduction and energy metabolism. Here, the effects of atrazine regarding survival and redox metabolism were assessed in the fruit fly D. melanogaster exposed during embryonic and larval development. The embryos (newly fertilized eggs) were exposed to different atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Pupation and emergence rates, developmental time and sex ratio were determined as well as oxidative stress parameters and gene expression of the antioxidant defence system were evaluated in newly emerged male and female flies. Atrazine exposure reduced pupation and emergence rates in fruit flies without alterations to developmental time and sex ratio. Different redox imbalance patterns were observed between males and females exposed to atrazine. Atrazine caused an increase in oxidative damage, reactive oxygen species generation and antioxidant capacity and decreased thiol-containing molecules. Further, atrazine exposure altered the mRNA expression of antioxidant genes (keap1, sod, sod2, cat, irc, gss, gclm, gclc, trxt, trxr-1 and trxr-2). Reductions in fruit fly larval and pupal viability observed here are likely consequences of the oxidative stress induced by atrazine exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Testing developmental pathways to antisocial personality problems

    NARCIS (Netherlands)

    S. Diamantopoulou; F.C. Verhulst (Frank); J. van der Ende (Jan)

    2010-01-01

    textabstractThis study examined the development of antisocial personality problems (APP) in young adulthood from disruptive behaviors and internalizing problems in childhood and adolescence. Parent ratings of 507 children's (aged 6-8 years) symptoms of attention deficit hyperactivity disorder,

  17. Testing Developmental Pathways to Antisocial Personality Problems

    Science.gov (United States)

    Diamantopoulou, Sofia; Verhulst, Frank C.; van der Ende, Jan

    2010-01-01

    This study examined the development of antisocial personality problems (APP) in young adulthood from disruptive behaviors and internalizing problems in childhood and adolescence. Parent ratings of 507 children's (aged 6-8 years) symptoms of attention deficit hyperactivity disorder, oppositional defiant disorder, and anxiety, were linked to…

  18. Larval Population Density Alters Adult Sleep in Wild-Type Drosophila melanogaster but Not in Amnesiac Mutant Flies

    Directory of Open Access Journals (Sweden)

    Michael W. Chi

    2014-08-01

    Full Text Available Sleep has many important biological functions, but how sleep is regulated remains poorly understood. In humans, social isolation and other stressors early in life can disrupt adult sleep. In fruit flies housed at different population densities during early adulthood, social enrichment was shown to increase subsequent sleep, but it is unknown if population density during early development can also influence adult sleep. To answer this question, we maintained Drosophila larvae at a range of population densities throughout larval development, kept them isolated during early adulthood, and then tested their sleep patterns. Our findings reveal that flies that had been isolated as larvae had more fragmented sleep than those that had been raised at higher population densities. This effect was more prominent in females than in males. Larval population density did not affect sleep in female flies that were mutant for amnesiac, which has been shown to be required for normal memory consolidation, adult sleep regulation, and brain development. In contrast, larval population density effects on sleep persisted in female flies lacking the olfactory receptor or83b, suggesting that olfactory signals are not required for the effects of larval population density on adult sleep. These findings show that population density during early development can alter sleep behavior in adulthood, suggesting that genetic and/or structural changes are induced by this developmental manipulation that persist through metamorphosis.

  19. Fish larval transport in the coastal waters through ecological modelling

    Digital Repository Service at National Institute of Oceanography (India)

    George, G.

    are as follows: (i) to find out the influence of environmental parameters on the biology of the given ecosystem (ii) to track larval transport and biological abundance in relation to environmental vari- ables (iii) to compare biological abundance and fish larval... include the following investigations: (i) analysis of satellite chlorophyll data along the southwest coastal waters of India to derive a biological calender for sardine (ii) tracking the larval survival and establish a link between food and sardine inter...

  20. Nitric oxide inhibits larval settlement in Amphibalanus amphitrite cyprids by repressing muscle locomotion and molting

    KAUST Repository

    Zhang, Gen; Wong, Yue-Him; Zhang, Yu; He, Li-sheng; Xu, Ying; Qian, Pei-Yuan

    2015-01-01

    Nitric oxide (NO) is a universal signaling molecule and plays a negative role in the metamorphosis of many biphasic organisms. Recently, the NO/NO (cyclic guanosine monophosphate) signaling pathway was reported to repress larval settlement in the barnacle Amphibalanus amphitrite. To understand the underlying molecular mechanism, we analyzed changes in the proteome of A. amphitrite cyprids in response to different concentrations of the NO donor sodium nitroprusside (SNP; 62.5, 250 and 1000 μM) using a label-free proteomics method. Compared with the control, the expression of 106 proteins differed in all three treatments. These differentially expressed proteins were assigned to 13 pathways based on KEGG pathway enrichment analysis. SNP treatment stimulated the expression of heat shock proteins and arginine kinase, which are functionally related to NO synthases, increased the expression levels of glutathione transferases for detoxification, and activated the iron-mediated fatty acid degradation pathway and the citrate cycle through ferritin. Moreover, NO repressed the level of myosins and cuticular proteins, which indicated that NO might inhibit larval settlement in A. amphitrite by modulating the process of muscle locomotion and molting.

  1. Nitric oxide inhibits larval settlement in Amphibalanus amphitrite cyprids by repressing muscle locomotion and molting

    KAUST Repository

    Zhang, Gen

    2015-08-28

    Nitric oxide (NO) is a universal signaling molecule and plays a negative role in the metamorphosis of many biphasic organisms. Recently, the NO/NO (cyclic guanosine monophosphate) signaling pathway was reported to repress larval settlement in the barnacle Amphibalanus amphitrite. To understand the underlying molecular mechanism, we analyzed changes in the proteome of A. amphitrite cyprids in response to different concentrations of the NO donor sodium nitroprusside (SNP; 62.5, 250 and 1000 μM) using a label-free proteomics method. Compared with the control, the expression of 106 proteins differed in all three treatments. These differentially expressed proteins were assigned to 13 pathways based on KEGG pathway enrichment analysis. SNP treatment stimulated the expression of heat shock proteins and arginine kinase, which are functionally related to NO synthases, increased the expression levels of glutathione transferases for detoxification, and activated the iron-mediated fatty acid degradation pathway and the citrate cycle through ferritin. Moreover, NO repressed the level of myosins and cuticular proteins, which indicated that NO might inhibit larval settlement in A. amphitrite by modulating the process of muscle locomotion and molting.

  2. C. elegans GATA factors EGL-18 and ELT-6 function downstream of Wnt signaling to maintain the progenitor fate during larval asymmetric divisions of the seam cells.

    Science.gov (United States)

    Gorrepati, Lakshmi; Thompson, Kenneth W; Eisenmann, David M

    2013-05-01

    The C. elegans seam cells are lateral epithelial cells arrayed in a single line from anterior to posterior that divide in an asymmetric, stem cell-like manner during larval development. These asymmetric divisions are regulated by Wnt signaling; in most divisions, the posterior daughter in which the Wnt pathway is activated maintains the progenitor seam fate, while the anterior daughter in which the Wnt pathway is not activated adopts a differentiated hypodermal fate. Using mRNA tagging and microarray analysis, we identified the functionally redundant GATA factor genes egl-18 and elt-6 as Wnt pathway targets in the larval seam cells. EGL-18 and ELT-6 have previously been shown to be required for initial seam cell specification in the embryo. We show that in larval seam cell asymmetric divisions, EGL-18 is expressed strongly in the posterior seam-fated daughter. egl-18 and elt-6 are necessary for larval seam cell specification, and for hypodermal to seam cell fate transformations induced by ectopic Wnt pathway overactivation. The TCF homolog POP-1 binds a site in the egl-18 promoter in vitro, and this site is necessary for robust seam cell expression in vivo. Finally, larval overexpression of EGL-18 is sufficient to drive expression of a seam marker in other hypodermal cells in wild-type animals, and in anterior hypodermal-fated daughters in a Wnt pathway-sensitized background. These data suggest that two GATA factors that are required for seam cell specification in the embryo independently of Wnt signaling are reused downstream of Wnt signaling to maintain the progenitor fate during stem cell-like divisions in larval development.

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

    Science.gov (United States)

    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.

  4. RNAseq analysis of the parasitic nematode Strongyloides stercoralis reveals divergent regulation of canonical dauer pathways.

    Directory of Open Access Journals (Sweden)

    Jonathan D Stoltzfus

    Full Text Available The infectious form of many parasitic nematodes, which afflict over one billion people globally, is a developmentally arrested third-stage larva (L3i. The parasitic nematode Strongyloides stercoralis differs from other nematode species that infect humans, in that its life cycle includes both parasitic and free-living forms, which can be leveraged to investigate the mechanisms of L3i arrest and activation. The free-living nematode Caenorhabditis elegans has a similar developmentally arrested larval form, the dauer, whose formation is controlled by four pathways: cyclic GMP (cGMP signaling, insulin/IGF-1-like signaling (IIS, transforming growth factor β (TGFβ signaling, and biosynthesis of dafachronic acid (DA ligands that regulate a nuclear hormone receptor. We hypothesized that homologous pathways are present in S. stercoralis, have similar developmental regulation, and are involved in L3i arrest and activation. To test this, we undertook a deep-sequencing study of the polyadenylated transcriptome, generating over 2.3 billion paired-end reads from seven developmental stages. We constructed developmental expression profiles for S. stercoralis homologs of C. elegans dauer genes identified by BLAST searches of the S. stercoralis genome as well as de novo assembled transcripts. Intriguingly, genes encoding cGMP pathway components were coordinately up-regulated in L3i. In comparison to C. elegans, S. stercoralis has a paucity of genes encoding IIS ligands, several of which have abundance profiles suggesting involvement in L3i development. We also identified seven S. stercoralis genes encoding homologs of the single C. elegans dauer regulatory TGFβ ligand, three of which are only expressed in L3i. Putative DA biosynthetic genes did not appear to be coordinately regulated in L3i development. Our data suggest that while dauer pathway genes are present in S. stercoralis and may play a role in L3i development, there are significant differences between

  5. Turbulence-enhanced prey encounter rates in larval fish : Effects of spatial scale, larval behaviour and size

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; MacKenzie, Brian

    1995-01-01

    Turbulent water motion has several effects on the feeding ecology of larval fish and other planktivorous predators. In this paper, we consider the appropriate spatial scales for estimating relative velocities between larval fish predators and their prey, and the effect that different choices of s...... in the range in which turbulent intensity has an overall positive effect on larval fish ingestion rate probability. However, experimental data to test the model predictions are lacking. We suggest that the model inputs require further empirical study....

  6. Adaptive locomotor behavior in larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2011-01-01

    In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish.

  7. Larval biometry of Simulium rubrithorax (Diptera: Simuliidae and size comparison between populations in the states of Minas Gerais and Roraima, Brazil

    Directory of Open Access Journals (Sweden)

    Alvan-Aguilar Miriam Adriana

    2003-01-01

    Full Text Available The number of larval instars of Simulium (Hemicnetha rubrithorax Lutz (Diptera: Nematocera was determined using the lateral length of the head capsule. In this study 1,035 larvae, of different sizes, were measured (639 from the state of Roraima and 396 from the state of Minas Gerais. A frequency distribution analysis was carried out on the measurements of the lateral length of the head capsule to determine the number of larval instars. The limits of each instar were defined by the lower frequency of the measurements falling in a range of values, by the presence of the "egg burster" that characterizes the first larval instar, and by the developmental stage of the gill histoblast. The determination of the instar number was tested using a Student's t-test (p 0.05 were observed between them.

  8. Larval stages Nymphon charcoti Bouvier 1911

    Directory of Open Access Journals (Sweden)

    John A. Fornshell

    2017-03-01

    Full Text Available The protonymphon larva and next four instars of the pycnogonids Nymphon charcoti are described. The developmental pattern is that of a "Typical Protonymphon" according to Bain's 2003 classification. The description is based on archived specimens from the National Museum of Natural History collections. The walking legs appear initially as underived buds with three pseudo-segments beginning with walking leg one in the second instar. In the subsequent instars the walking legs appear as six segmented appendages and then eight segmented appendages. In the genus Nymphon there are four different post embryonic developmental patterns, "Typical Protonymphon", "Attaching Larva", "Lecithotrophic Larva" and "Elvie's Larva". This diversity of developmental patterns within the same genus which is not restricted to the Nymphonidae indicates that the developmental patterns as currently defined in the literature have little phylogenetic relevance.

  9. Microhabitat influence on larval fish assemblages within ...

    Science.gov (United States)

    We examined larval and juvenile fish assemblage structure in relation to microhabitat variables within the St. Louis River estuary, a drowned river mouth of Lake Superior. Fish were sampled in vegetated beds throughout the estuary, across a gradient of vegetation types and densities (including disturbed, preserved and post-restoration sites). Canonical correspondence analysis, relating species abundances to environmental variables revealed that plant species richness, turbidity and aquatic plant cover were most influential in structuring assemblages. Results from this microhabitat analysis at this crucial life stage has potential to inform wetland restoration efforts within the St. Louis River and other Great Lake coastal wetlands. not applicable

  10. Developmental Defects of Caenorhabditis elegans Lacking Branched-chain α-Ketoacid Dehydrogenase Are Mainly Caused by Monomethyl Branched-chain Fatty Acid Deficiency.

    Science.gov (United States)

    Jia, Fan; Cui, Mingxue; Than, Minh T; Han, Min

    2016-02-05

    Branched-chain α-ketoacid dehydrogenase (BCKDH) catalyzes the critical step in the branched-chain amino acid (BCAA) catabolic pathway and has been the focus of extensive studies. Mutations in the complex disrupt many fundamental metabolic pathways and cause multiple human diseases including maple syrup urine disease (MSUD), autism, and other related neurological disorders. BCKDH may also be required for the synthesis of monomethyl branched-chain fatty acids (mmBCFAs) from BCAAs. The pathology of MSUD has been attributed mainly to BCAA accumulation, but the role of mmBCFA has not been evaluated. Here we show that disrupting BCKDH in Caenorhabditis elegans causes mmBCFA deficiency, in addition to BCAA accumulation. Worms with deficiency in BCKDH function manifest larval arrest and embryonic lethal phenotypes, and mmBCFA supplementation suppressed both without correcting BCAA levels. The majority of developmental defects caused by BCKDH deficiency may thus be attributed to lacking mmBCFAs in worms. Tissue-specific analysis shows that restoration of BCKDH function in multiple tissues can rescue the defects, but is especially effective in neurons. Taken together, we conclude that mmBCFA deficiency is largely responsible for the developmental defects in the worm and conceivably might also be a critical contributor to the pathology of human MSUD. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Elevated copper levels during larval development cause altered locomotor behavior in the adult carabid beetle Pterostichus cupreus L. (Coleoptera: Carbidae)

    DEFF Research Database (Denmark)

    Bayley, M; Baatrup, E; Heimbach, U

    1995-01-01

    behavior of adult Pterostichus cupreus carabid beetles was quantified after being raised on copper-contaminated food and soil during larval development. Copper was found to have an acute toxic effect measured in larval mortality, to cause a slight increase in the developmental period of males......It is generally believed that copper causes changes in carabid communities indirectly by reducing food availability, because these animals are frequently found to have only slightly elevated metal contents even close to pollution sources. Using computer-centered video tracking, the locomotor......, but not to effect the emergence weights of adults of either sex. This toxic effect on the larvae was preserved through pupation to the surviving adults, which were normal in size and appearance, but displayed a dramatically depressed locomotor behavior. Copper analysis of these adults revealed that copper levels...

  12. Developmental dyscalculia.

    Science.gov (United States)

    Kucian, Karin; von Aster, Michael

    2015-01-01

    Numerical skills are essential in our everyday life, and impairments in the development of number processing and calculation have a negative impact on schooling and professional careers. Approximately 3 to 6 % of children are affected from specific disorders of numerical understanding (developmental dyscalculia (DD)). Impaired development of number processing skills in these children is characterized by problems in various aspects of numeracy as well as alterations of brain activation and brain structure. Moreover, DD is assumed to be a very heterogeneous disorder putting special challenges to define homogeneous diagnostic criteria. Finally, interdisciplinary perspectives from psychology, neuroscience and education can contribute to the design for interventions, and although results are still sparse, they are promising and have shown positive effects on behaviour as well as brain function. In the current review, we are going to give an overview about typical and atypical development of numerical abilities at the behavioural and neuronal level. Furthermore, current status and obstacles in the definition and diagnostics of DD are discussed, and finally, relevant points that should be considered to make an intervention as successful as possible are summarized.

  13. Analysis of a lin-42/period Null Allele Implicates All Three Isoforms in Regulation of Caenorhabditis elegans Molting and Developmental Timing

    Directory of Open Access Journals (Sweden)

    Theresa L. B. Edelman

    2016-12-01

    Full Text Available The Caenorhabditis elegans heterochronic gene pathway regulates the relative timing of events during postembryonic development. lin-42, the worm homolog of the circadian clock gene, period, is a critical element of this pathway. lin-42 function has been defined by a set of hypomorphic alleles that cause precocious phenotypes, in which later developmental events, such as the terminal differentiation of hypodermal cells, occur too early. A subset of alleles also reveals a significant role for lin-42 in molting; larval stages are lengthened and ecdysis often fails in these mutant animals. lin-42 is a complex locus, encoding overlapping and nonoverlapping isoforms. Although existing alleles that affect subsets of isoforms have illuminated important and distinct roles for this gene in developmental timing, molting, and the decision to enter the alternative dauer state, it is essential to have a null allele to understand all of the roles of lin-42 and its individual isoforms. To remedy this problem and discover the null phenotype, we engineered an allele that deletes the entire lin-42 protein-coding region. lin-42 null mutants are homozygously viable, but have more severe phenotypes than observed in previously characterized hypomorphic alleles. We also provide additional evidence for this conclusion by using the null allele as a base for reintroducing different isoforms, showing that each isoform can provide heterochronic and molting pathway activities. Transcript levels of the nonoverlapping isoforms appear to be under coordinate temporal regulation, despite being driven by independent promoters. The lin-42 null allele will continue to be an important tool for dissecting the functions of lin-42 in molting and developmental timing.

  14. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 85; Issue 3. Reduced larval feeding rate is a strong evolutionary correlate of rapid development in Drosophila melanogaster. M. Rajamani N. Raghavendra ... Keywords. life-history evolution; development time; larval feeding rate; competition; tradeoffs; Drosophila melanogaster.

  15. The larval development of the red mangrove crab Sesarma meinerti ...

    African Journals Online (AJOL)

    The larval stages of the red mangrove crab Sesarma meinerti de Man were reared in the laboratory. Larval development consists of five zoeal stages and one megalopa. Zoeal development lasts an average of 25 days at 25°C. The external morphology of larvae is described in detail and their relationship with larvae of.

  16. Species associations among larval helminths in an amphipod intermediate host.

    Science.gov (United States)

    Dezfuli, B S; Giari, L; Poulin, R

    2000-10-01

    Larval helminths that share the same intermediate host may or may not also share the same definitive hosts. If one or more of these helminth species can manipulate the phenotype of the intermediate host, there can be great advantages or severe costs for other helminths resulting from co-occurring with a manipulator, depending on whether they have the same definitive host or not. Among 2372 specimens of the amphipod Echinogammarus stammeri collected from the river Brenta, northern Italy, there was a positive association between two acanthocephalan species with the same fish definitive hosts, the relatively common Pomphorhynchus laevis and the much less prevalent Acanthocephalus clavula. The number of cystacanths of P. laevis per infected amphipod, which ranged from one to five, did not influence the likelihood that the amphipod would also host A. clavula. A third acanthocephalan species, Polymorphus minutus,which matures in birds, showed no association with either of the two other species. These results show that associations among helminth species in intermediate hosts are not random, and are instead the product of selection favouring certain pathways of transmission.

  17. Interactive Effects of Endogenous and Exogenous Nutrition on Larval Development for Crown-Of-Thorns Starfish

    Directory of Open Access Journals (Sweden)

    Ciemon Frank Caballes

    2017-03-01

    Full Text Available Outbreaks of crown-of-thorns starfish are often attributed to step-changes in larval survivorship following anomalous increases in nutrients and food availability. However, larval growth and development is also influenced by the nutritional condition of spawning females, such that maternal provisioning may offset limitations imposed by limited access to exogenous sources of nutrients during the formative stages of larval development. This study examined the individual, additive, and interactive effects of endogenous (maternal diet: Acropora, Porites, mixed, and starved and exogenous (larval diet: high concentration at 104 cells·mL−1, low concentration at 103 algal cells·mL−1, and starved nutrition on the survival, growth, morphology, and development of larvae of the crown-of-thorns starfish. Female starfish on Acropora and mixed diet produced bigger oocytes compared to Porites-fed and starved treatments. Using oocyte size as a proxy for maternal provisioning, endogenous reserves in the oocyte had a strong influence on initial larval survival and development. This suggests that maternal reserves can delay the onset of obligate exogenous food acquisition and allow larvae to endure prolonged periods of poor environmental nutritive conditions or starvation. The influence of exogenous nutrition became more prominent in later stages, whereby none of the starved larvae reached the mid-to-late brachiolaria stage 16 days after the onset of the ability to feed. There was no significant difference in the survival, development, and competency of larvae between high and low food treatments. Under low algal food conditions, larvae compensate by increasing the length of ciliated feeding bands in relation to the maximum length and width, which improve food capture and feeding efficiency. However, the effects of endogenous nutrition persisted in the later developmental stages, as larvae from starved females were unable to develop larger feeding structures

  18. Increased long-flight activity triggered in beet armyworm by larval feeding on diet containing Cry1Ac protoxin.

    Directory of Open Access Journals (Sweden)

    Xing Fu Jiang

    Full Text Available Evaluating ecological safety and conducting pest risk analysis for transgenic crops are vitally important before their commercial planting. The beet armyworm, Spodoptera exigua, a long-distance migratory insect pest, is not a direct target of transgenic Cry1Ac-expressing cotton in China, but nevertheless it has recently become an important pest. Migrants leaving their natal field arrive in other appropriate habitat far away in a short time, often followed by larval outbreaks. S. exigua has low susceptibility to Cry1Ac. However, our results from laboratory experiments identified (i sublethal effects of Cry1Ac protoxin on larval development rate, larval and pupal weight, and adult lifetime fecundity, and (ii increased long-flight behavior triggered by Cry1Ac which may contribute to larval outbreaks elsewhere. No significant differences in larval mortality, pupation rate, adult emergence rate, longevity, pre-oviposition period, or oviposition period were observed between controls and larvae fed on artificial diet incorporating a low concentration of Cry1Ac protoxin. The negative sublethal effects on some developmental and reproductive traits and lack of effect on others suggest they do not contribute to the observed severity of S. exigua outbreaks after feeding on Cry1Ac cotton. Interestingly, the percentage of long fliers increased significantly when larvae were reared on diet containing either of two low-dose treatments of Cry1Ac, suggesting a possible increased propensity to disperse long distances triggered by Cry1Ac. We hypothesize that negative effects on development and reproduction caused by Cry1Ac in the diet are offset by increased flight propensity triggered by the poor food conditions, thereby improving the chances of escaping adverse local conditions before oviposition. Increased long-flight propensity in turn may amplify the area damaged by outbreak populations. This phenomenon might be common in other migratory insect pests receiving

  19. Involvement of a novel p38 mitogen-activated protein kinase in larval metamorphosis of the polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Wang, Hao

    2010-04-19

    Hydroides elegans is a common marine fouling organism in most tropical and subtropical waters. The life cycle of H. elegans includes a planktonic larval stage in which swimming larvae normally take 5 days to attain competency to settle. Larval metamorphosis marks the beginning of its benthic life; however, the endogenous molecular mechanisms that regulate metamorphosis remain largely unknown. In this study, a PCR-based suppressive subtractive hybridization (SSH) library was constructed to screen the genes expressed in competent larvae but not in precompetent larvae. Among the transcripts isolated from the library, 21 significantly matched sequences in the GenBank. Many of these isolated transcripts have putative roles in the reactive oxygen species (ROS) signal transduction pathway or in response to ROS stress. A putative novel p38 mitogen-activated protein kinase (MAPK), which was also isolated with SSH screen, was then cloned and characterized. The MAPK inhibitors assay showed that both p38 MAPK inhibitors SB202190 and SB203580 effectively inhibited the biofilm-induced metamorphosis of H. elegans. A cell stressors assay showed that H2O2 effectively induced larval metamorphosis of H. elegans, but the inductivity of H2O2 was also inhibited by both SB inhibitors. The catalase assay showed that the catalase could effetely inhibit H. elegans larvae from responding to inductive biofilm. These results showed that the p38 MAPK-dependent pathway plays critical role in controlling larval metamorphosis of the marine polychaete H. elegans, and the reactive oxygen radicals produced by biofilm could be the cue inducing larval metamorphosis. © 2010 Wiley-Liss, Inc.

  20. Developmental rate and behavior of early life stages of bighead carp and silver carp

    Science.gov (United States)

    Chapman, Duane C.; George, Amy E.

    2011-01-01

    The early life stages of Asian carp are well described by Yi and others (1988), but since these descriptions are represented by line drawings based only on live individuals and lacked temperature controls, further information on developmental time and stages is of use to expand understanding of early life stages of these species. Bighead carp and silver carp were cultured under two different temperature treatments to the one-chamber gas bladder stage, and a photographic guide is provided for bighead carp and silver carp embryonic and larval development, including notes about egg morphology and larval swimming behavior. Preliminary information on developmental time and hourly thermal units for each stage is also provided. Both carp species developed faster under warmer conditions. Developmental stages and behaviors are generally consistent with earlier works with the exception that strong vertical swimming immediately after hatching was documented in this report.

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

    Science.gov (United States)

    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

  2. Uncovering the immune responses of Apis mellifera ligustica larval gut to Ascosphaera apis infection utilizing transcriptome sequencing.

    Science.gov (United States)

    Chen, Dafu; Guo, Rui; Xu, Xijian; Xiong, Cuiling; Liang, Qin; Zheng, Yanzhen; Luo, Qun; Zhang, Zhaonan; Huang, Zhijian; Kumar, Dhiraj; Xi, Weijun; Zou, Xuan; Liu, Min

    2017-07-20

    Honeybees are susceptible to a variety of diseases, including chalkbrood, which is capable of causing huge losses of both the number of bees and colony productivity. This research is designed to characterize the transcriptome profiles of Ascosphaera apis-treated and un-treated larval guts of Apis mellifera ligustica in an attempt to unravel the molecular mechanism underlying the immune responses of western honeybee larval guts to mycosis. In this study, 24, 296 and 2157 genes were observed to be differentially expressed in A. apis-treated Apis mellifera (4-, 5- and 6-day-old) compared with un-treated larval guts. Moreover, the expression patterns of differentially expressed genes (DEGs) were examined via trend analysis, and subsequently, gene ontology analysis and KEGG pathway enrichment analysis were conducted for DEGs involved in up- and down-regulated profiles. Immunity-related pathways were selected for further analysis, and our results demonstrated that a total of 13 and 50 DEGs were annotated in the humoral immune-related and cellular immune-related pathways, respectively. Additionally, we observed that many DEGs up-regulated in treated guts were part of cellular immune pathways, such as the lysosome, ubiquitin mediated proteolysis, and insect hormone biosynthesis pathways and were induced by A. apis invasion. However, more down-regulated DEGs were restrained. Surprisingly, a majority of DEGs within the Toll-like receptor signaling pathway, and the MAPK signaling pathway were up-regulated in treated guts, while all but two genes involved in the NF-κB signaling pathway were down-regulated, which suggested that most genes involved in humoral immune-related pathways were activated in response to the invasive fungal pathogen. This study's findings provide valuable information regarding the investigation of the molecular mechanism of immunity defenses of A. m. ligustica larval guts to infection with A. apis. Furthermore, these studies lay the groundwork for

  3. Mosquito larval source management for controlling malaria

    Science.gov (United States)

    Tusting, Lucy S; Thwing, Julie; Sinclair, David; Fillinger, Ulrike; Gimnig, John; Bonner, Kimberly E; Bottomley, Christian; Lindsay, Steven W

    2015-01-01

    Background Malaria is an important cause of illness and death in people living in many parts of the world, especially sub-Saharan Africa. Long-lasting insecticide treated bed nets (LLINs) and indoor residual spraying (IRS) reduce malaria transmission by targeting the adult mosquito vector and are key components of malaria control programmes. However, mosquito numbers may also be reduced by larval source management (LSM), which targets mosquito larvae as they mature in aquatic habitats. This is conducted by permanently or temporarily reducing the availability of larval habitats (habitat modification and habitat manipulation), or by adding substances to standing water that either kill or inhibit the development of larvae (larviciding). Objectives To evaluate the effectiveness of mosquito LSM for preventing malaria. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CABS Abstracts; and LILACS up to 24 October 2012. We handsearched the Tropical Diseases Bulletin from 1900 to 2010, the archives of the World Health Organization (up to 11 February 2011), and the literature database of the Armed Forces Pest Management Board (up to 2 March 2011). We also contacted colleagues in the field for relevant articles. Selection criteria We included cluster randomized controlled trials (cluster-RCTs), controlled before-and-after trials with at least one year of baseline data, and randomized cross-over trials that compared LSM with no LSM for malaria control. We excluded trials that evaluated biological control of anopheline mosquitoes with larvivorous fish. Data collection and analysis At least two authors assessed each trial for eligibility. We extracted data and at least two authors independently determined the risk of bias in the included studies. We resolved all disagreements through discussion with a third author. We analyzed the data using Review Manager 5 software

  4. Host selection by the pine processionary moth enhances larval performance: An experiment

    Science.gov (United States)

    Pérez-Contreras, Tomás; Soler, Juan J.; Soler, Manuel

    2014-02-01

    The development of a phytophagous insect depends on the nutritional characteristics of plants on which it feeds. Offspring from different females, however, may vary in their ability to develop in different host species and therefore females should place their eggs on host plants that result in the highest performance for the insect offspring. Causes underlying the predicted relationships between host selection and offspring performance may be: (1) a genetic association between larval ability to exploit particular hosts and the female insect's host preference; and (2) phenotypic plasticity of larvae that may be due to (a) maternal effects (e.g. differential investment in eggs) or (b) diet. In this work, we analyse the performance (i.e. hatching success and larval size and mortality) of the pine processionary (Thaumetopoea pityocampa) caterpillar developing in Aleppo (Pinus halepensis) or maritime (Pinus pinaster) pines. Larvae of this moth species do not move from the individual pine selected by the mother for oviposition. By means of cross-fostering experiments of eggs batches and silk nests of larvae between these two pine species, we explored whether phenotypic plasticity of offspring traits or genetic correlations between mother and offspring traits account for variation in developmental characteristics of caterpillars. Our results showed that females preferentially selected Aleppo pine for oviposition. Moreover, the offspring had the highest probability of survival and reached a larger body size in this pine species independently of whether or not batches were experimentally cross-fostered. Notably, the interaction between identity of donor and receiver pine species of larvae nests explained a significant proportion of variance of larval size and mortality, suggesting a role of diet-induced phenotypic plasticity of the hatchlings. These results suggest that both female selection of the more appropriate pine species and phenotypic plasticity of larva explain the

  5. A developmental timing switch promotes axon outgrowth independent of known guidance receptors.

    Directory of Open Access Journals (Sweden)

    Katherine Olsson-Carter

    2010-08-01

    Full Text Available To form functional neuronal connections, axon outgrowth and guidance must be tightly regulated across space as well as time. While a number of genes and pathways have been shown to control spatial features of axon development, very little is known about the in vivo mechanisms that direct the timing of axon initiation and elongation. The Caenorhabditis elegans hermaphrodite specific motor neurons (HSNs extend a single axon ventrally and then anteriorly during the L4 larval stage. Here we show the lin-4 microRNA promotes HSN axon initiation after cell cycle withdrawal. Axons fail to form in lin-4 mutants, while they grow prematurely in lin-4-overexpressing animals. lin-4 is required to down-regulate two inhibitors of HSN differentiation--the transcriptional regulator LIN-14 and the "stemness" factor LIN-28--and it likely does so through a cell-autonomous mechanism. This developmental switch depends neither on the UNC-40/DCC and SAX-3/Robo receptors nor on the direction of axon growth, demonstrating that it acts independently of ventral guidance signals to control the timing of HSN axon elongation.

  6. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    Directory of Open Access Journals (Sweden)

    Qian Pei-Yuan

    2011-09-01

    Full Text Available Abstract Background The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles. Results Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles. Conclusion It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes.

  7. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2011-09-03

    Background: The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE) followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles.Results: Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles.Conclusion: It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes. © 2011 Chandramouli et al; licensee BioMed Central Ltd.

  8. Plant microRNAs in larval food regulate honeybee caste development.

    Science.gov (United States)

    Zhu, Kegan; Liu, Minghui; Fu, Zheng; Zhou, Zhen; Kong, Yan; Liang, Hongwei; Lin, Zheguang; Luo, Jun; Zheng, Huoqing; Wan, Ping; Zhang, Junfeng; Zen, Ke; Chen, Jiong; Hu, Fuliang; Zhang, Chen-Yu; Ren, Jie; Chen, Xi

    2017-08-01

    The major environmental determinants of honeybee caste development come from larval nutrients: royal jelly stimulates the differentiation of larvae into queens, whereas beebread leads to worker bee fate. However, these determinants are not fully characterized. Here we report that plant RNAs, particularly miRNAs, which are more enriched in beebread than in royal jelly, delay development and decrease body and ovary size in honeybees, thereby preventing larval differentiation into queens and inducing development into worker bees. Mechanistic studies reveal that amTOR, a stimulatory gene in caste differentiation, is the direct target of miR162a. Interestingly, the same effect also exists in non-social Drosophila. When such plant RNAs and miRNAs are fed to Drosophila larvae, they cause extended developmental times and reductions in body weight and length, ovary size and fecundity. This study identifies an uncharacterized function of plant miRNAs that fine-tunes honeybee caste development, offering hints for understanding cross-kingdom interaction and co-evolution.

  9. Differential expression of proteins and phosphoproteins during larval metamorphosis of the polychaete Capitella sp. I

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Soo, Lisa; Qian, Pei-Yuan

    2011-01-01

    Background: The spontaneous metamorphosis of the polychaete Capitella sp. I larvae into juveniles requires minor morphological changes, including segment formation, body elongation, and loss of cilia. In this study, we investigated changes in the expression patterns of both proteins and phosphoproteins during the transition from larvae to juveniles in this species. We used two-dimensional gel electrophoresis (2-DE) followed by multiplex fluorescent staining and MALDI-TOF mass spectrometry analysis to identify the differentially expressed proteins as well as the protein and phosphoprotein profiles of both competent larvae and juveniles.Results: Twenty-three differentially expressed proteins were identified in the two developmental stages. Expression patterns of two of those proteins were examined at the protein level by Western blot analysis while seven were further studied at the mRNA level by real-time PCR. Results showed that proteins related to cell division, cell migration, energy storage and oxidative stress were plentifully expressed in the competent larvae; in contrast, proteins involved in oxidative metabolism and transcriptional regulation were abundantly expressed in the juveniles.Conclusion: It is likely that these differentially expressed proteins are involved in regulating the larval metamorphosis process and can be used as protein markers for studying molecular mechanisms associated with larval metamorphosis in polychaetes. © 2011 Chandramouli et al; licensee BioMed Central Ltd.

  10. Larval fish variability in response to oceanographic features in a nearshore nursery area.

    Science.gov (United States)

    Pattrick, P; Strydom, N A

    2014-09-01

    The influence of oceanographic features on ichthyoplankton assemblages in the warm temperate nearshore region of Algoa Bay, South Africa, was assessed. The nearshore ichthyoplankton comprised 88 taxa from 34 families. Samples were collected at six stations between August 2010 and July 2012 using a plankton ring net of 750 mm diameter and 500 µm mesh aperture. The majority of larvae collected were in a preflexion stage, indicating the potential importance of the nearshore for newly hatched larvae. Engraulidae dominated the catch (38·4%), followed by Cynoglossidae (28·1%) and Sparidae (8·4%). Larval fish abundance was highest during austral spring and summer (September to February). Unique patterns in responses of each dominant fish species to oceanographic features in the nearshore indicate the sensitivity of the early developmental stage to environmental variables. Using generalized linear models, ichthyoplankton abundance responded positively to upwelling and when warm water plumes originating from an Agulhas Current meander entered Algoa Bay. Highest abundances of Engraulis encrasicolus and Sardinops sagax were observed during Agulhas Plume intrusions into Algoa Bay. When a mixed and stratified water column persisted in the nearshore region of Algoa Bay, larval fish abundance decreased. The nearshore region of Algoa Bay appears to serve as a favourable environment for the accumulation of ichthyoplankton. © 2014 The Fisheries Society of the British Isles.

  11. Larval development of Sabellastarte spectabilis (Grube, 1878 (Polychaeta: Sabellidae in Hawaiian waters

    Directory of Open Access Journals (Sweden)

    David R. Bybee

    2006-12-01

    Full Text Available The sabellid polychaete Sabellastarte spectabilis is common in bays and harbours throughout Hawaii. It has become one of the most harvested marine ornamental species in the State. Collection can be difficult and potentially damaging to the reef community. Understanding the reproduction and life history of this polychaete will benefit the marine ornamental trade by facilitating aquaculture of the species and coral reef conservation by decreasing destructive collecting practices. There is very little known about the biology of this species. Experiments were conducted at the Hawaii Institute of Marine Biology to induce and document spawning and larval development. Oocytes range between 150-200 µm in diameter and sperm have spherical heads. Cell division in fertilized eggs begins approximately twenty minutes after spawning. Developmental stages were documented using light and scanning electron microscopy. Swimming larvae are first seen 7-8 h after spawning. Larvae have a well-developed prototroch and a less conspicuous neurotroch and metatroch. Two chaetigers develop sequentially on days 4 and 5 and settlement occurs 6-7 days after spawning. Metamorphosis occurs gradually from days 6-8. This is the first reported induction of spawning and description of larval development from fertilized egg to settlement and metamorphosis for this species.

  12. Molecular characterization of larval development from fertilization to metamorphosis in a reef-building coral.

    Science.gov (United States)

    Strader, Marie E; Aglyamova, Galina V; Matz, Mikhail V

    2018-01-04

    Molecular mechanisms underlying coral larval competence, the ability of larvae to respond to settlement cues, determine their dispersal potential and are potential targets of natural selection. Here, we profiled competence, fluorescence and genome-wide gene expression in embryos and larvae of the reef-building coral Acropora millepora daily throughout 12 days post-fertilization. Gene expression associated with competence was positively correlated with transcriptomic response to the natural settlement cue, confirming that mature coral larvae are "primed" for settlement. Rise of competence through development was accompanied by up-regulation of sensory and signal transduction genes such as ion channels, genes involved in neuropeptide signaling, and G-protein coupled receptor (GPCRs). A drug screen targeting components of GPCR signaling pathways confirmed a role in larval settlement behavior and metamorphosis. These results gives insight into the molecular complexity underlying these transitions and reveals receptors and pathways that, if altered by changing environments, could affect dispersal capabilities of reef-building corals. In addition, this dataset provides a toolkit for asking broad questions about sensory capacity in multicellular animals and the evolution of development.

  13. Climate change and larval transport in the ocean: fractional effects from physical and physiological factors.

    Science.gov (United States)

    Kendall, Matthew S; Poti, Matt; Karnauskas, Kristopher B

    2016-04-01

    Changes in larval import, export, and self-seeding will affect the resilience of coral reef ecosystems. Climate change will alter the ocean currents that transport larvae and also increase sea surface temperatures (SST), hastening development, and shortening larval durations. Here, we use transport simulations to estimate future larval connectivity due to: (1) physical transport of larvae from altered circulation alone, and (2) the combined effects of altered currents plus physiological response to warming. Virtual larvae from islands throughout Micronesia were moved according to present-day and future ocean circulation models. The Hybrid Coordinate Ocean Model (HYCOM) spanning 2004-2012 represented present-day currents. For future currents, we altered HYCOM using analysis from the National Center for Atmospheric Research Community Earth System Model, version 1-Biogeochemistry, Representative Concentration Pathway 8.5 experiment. Based on the NCAR model, regional SST is estimated to rise 2.74 °C which corresponds to a ~17% decline in larval duration for some taxa. This reduction was the basis for a separate set of simulations. Results predict an increase in self-seeding in 100 years such that 62-76% of islands experienced increased self-seeding, there was an average domainwide increase of ~1-3% points in self-seeding, and increases of up to 25% points for several individual islands. When changed currents alone were considered, approximately half (i.e., random) of all island pairs experienced decreased connectivity but when reduced PLD was added as an effect, ~65% of connections were weakened. Orientation of archipelagos relative to currents determined the directional bias in connectivity changes. There was no universal relationship between climate change and connectivity applicable to all taxa and settings. Islands that presently export large numbers of larvae but that also maintain or enhance this role into the future should be the focus of conservation

  14. Embryonic, larval, and juvenile development of the sea biscuit Clypeaster subdepressus (Echinodermata: Clypeasteroida.

    Directory of Open Access Journals (Sweden)

    Bruno C Vellutini

    Full Text Available Sea biscuits and sand dollars diverged from other irregular echinoids approximately 55 million years ago and rapidly dispersed to oceans worldwide. A series of morphological changes were associated with the occupation of sand beds such as flattening of the body, shortening of primary spines, multiplication of podia, and retention of the lantern of Aristotle into adulthood. To investigate the developmental basis of such morphological changes we documented the ontogeny of Clypeaster subdepressus. We obtained gametes from adult specimens by KCl injection and raised the embryos at 26 degrees C. Ciliated blastulae hatched 7.5 h after sperm entry. During gastrulation the archenteron elongated continuously while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larvae began to feed in 3 d and were 20 d old at metamorphosis; starved larvae died 17 d after fertilization. Postlarval juveniles had neither mouth nor anus nor plates on the aboral side, except for the remnants of larval spicules, but their bilateral symmetry became evident after the resorption of larval tissues. Ossicles of the lantern were present and organized in 5 groups. Each group had 1 tooth, 2 demipyramids, and 2 epiphyses with a rotula in between. Early appendages consisted of 15 spines, 15 podia (2 types, and 5 sphaeridia. Podial types were distributed in accordance to Lovén's rule and the first podium of each ambulacrum was not encircled by the skeleton. Seven days after metamorphosis juveniles began to feed by rasping sand grains with the lantern. Juveniles survived in laboratory cultures for 9 months and died with wide, a single open sphaeridium per ambulacrum, aboral anus, and no differentiated food grooves or petaloids. Tracking the morphogenesis of early juveniles is a necessary step to elucidate the developmental mechanisms of echinoid growth and important groundwork to clarify homologies between irregular urchins.

  15. NMR Profiling of Metabolites in Larval and Juvenile Blue Mussels (Mytilus edulis) under Ambient and Low Salinity Conditions.

    Science.gov (United States)

    May, Melissa A; Bishop, Karl D; Rawson, Paul D

    2017-07-06

    Blue mussels ( Mytilus edulis ) are ecologically and economically important marine invertebrates whose populations are at risk from climate change-associated variation in their environment, such as decreased coastal salinity. Blue mussels are osmoconfomers and use components of the metabolome (free amino acids) to help maintain osmotic balance and cellular function during low salinity exposure. However, little is known about the capacity of blue mussels during the planktonic larval stages to regulate metabolites during osmotic stress. Metabolite studies in species such as blue mussels can help improve our understanding of the species' physiology, as well as their capacity to respond to environmental stress. We used 1D ¹H nuclear magnetic resonance (NMR) and 2D total correlation spectroscopy (TOCSY) experiments to describe baseline metabolite pools in larval (veliger and pediveliger stages) and juvenile blue mussels (gill, mantle, and adductor tissues) under ambient conditions and to quantify changes in the abundance of common osmolytes in these stages during low salinity exposure. We found evidence for stage- and tissue-specific differences in the baseline metabolic profiles of blue mussels, which reflect variation in the function and morphology of each larval stage or tissue type of juveniles. These differences impacted the utilization of osmolytes during low salinity exposure, likely stemming from innate physiological variation. This study highlights the importance of foundational metabolomic studies that include multiple tissue types and developmental stages to adequately evaluate organismal responses to stress and better place these findings in a broader physiological context.

  16. Cell cycle analysis of brain cells as a growth index in larval cod at different feeding conditions and temperatures

    Directory of Open Access Journals (Sweden)

    Rafael González-Quirós

    2007-09-01

    Full Text Available The percentage of cells dividing in a specific tissue of individual larvae can be estimated by analyzing DNA per cell by flow cytometry. An experimental test was carried out with cod (Gadus morhua larvae, with brain as the target tissue, to validate this technique as an appropriate growth index for larval fish. Standard length (SL, myotome height, and %S-phase (% of cells in the S-phase of the cell-division cycle variability were analyzed, with temperature (6 and 10°C, food level (high- and no-food and larval developmental stage (first feeding, pre-metamorphosis and post-metamorphosis as independent factors. Cod larvae grew faster (in SL and presented a higher %S-phase under high-food conditions. Larval SL increased with temperature in rearing and experimental tanks. However, there was a significant interaction between temperature and food in the %S-phase. There were no significant differences in the %S-phase between 6 and 10°C at high-food levels. We suggest that this result is a consequence of temperature-dependency of the duration of the cell cycle. In the absence of food, larvae at 10ºC had a lower %S-phase than larvae at 6°C, which may be related to increased metabolic costs with increasing temperature. Considering the effect of temperature, the mean % S-phase explained 74% of the variability in the estimated standard growth rate.

  17. Measurements and Counts for Larval and Juvenile Beryx Specimens

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Larval alfonsin (Beryx species) were collected in the vicinity of the Southeast Hancock Seamount. A three-net Tucker trawl (I m2 effective mouth opening and 0.333 mm...

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

    OpenAIRE

    Gendrin, MEM; Christophides; Linenberg, Inbar

    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. Clar...

  19. Contributions for larval development optimization of Homarus gammarus

    Directory of Open Access Journals (Sweden)

    Pedro Tiago Fonseca Sá

    2014-06-01

    The seawater rising temperature resulted in a decrease of intermoult period in all larval development stages and at all tested temperatures, ranging from 4.77 (Z1 to 16.5 days (Z3 at 16°C, whereas at 23°C, ranged from 3:02 (Z1 and 9.75 days (Z3. The results obtained are an extremely useful guide for future optimization of protocols on larval development of H. gammarus.

  20. The effect of rearing temperature in larval development of pejerrey, Odontesthes bonariensis: morphological indicators of development

    Directory of Open Access Journals (Sweden)

    Tomás Chalde

    2011-01-01

    Full Text Available It is well known that in pejerrey water temperature not only affects growth rates but also directs the sexual differentiation process. This fact rise the question of how different the development of pejerrey larvae of the same age is when reared at different temperatures. A description of developmental stages for the embryonic and larval periods of the pejerrey, Odontesthes bonariensis, and the influence of rearing temperature on larval development are presented. Then, larval development was studied at three rearing temperatures, and changes in general morphology, fin morphology, and caudal fin structure have been taken into consideration within the thermal range involved in the temperature sex determination of this species. Fin fold reabsorption, caudal fin formation, and body shape were selected to follow the events leading to the acquisition of the juvenile morphology. The juvenile phenotype was defined when the fin fold was reabsorpted and the caudal fin acquired its definitive homocercal structure. The moment at which the juvenile phenotype was achieved, was evaluated in relation to larval age, size and, shape. The size resulted as the best indicator of development in pejerrey.A temperatura da água não afeta apenas as taxas de crescimento no peixe-rei, mas também direciona o processo de diferenciação sexual. Este fato levanta o questionamento de quão diferente é o desenvolvimento de larvas do peixe-rei da mesma idade quando criadas em temperaturas diferentes. Este trabalho teve como objetivo apresentar uma descrição do de desenvolvimento de embriões e larvas do peixe-rei, Odontesthes bonariensis, e a influência da temperatura de criação no desenvolvimento das larvas. Neste trabalho, o desenvolvimento das larvas foi estudado em três temperaturas diferentes de cultivo. Foram consideradas as alterações ocorridas na morfologia geral, assim como na morfologia e na estrutura da nadadeira caudal dentro da variação termal da

  1. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.

    2012-08-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  2. The regulatory role of the NO/cGMP signal transduction cascade during larval attachment and metamorphosis of the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Zhang, Y.; He, L.-S.; Zhang, G.; Xu, Y.; Lee, O.-O.; Matsumura, K.; Qian, P.-Y.

    2012-01-01

    The barnacle Balanus amphitrite is among the most dominant fouling species on intertidal rocky shores in tropical and subtropical areas and is thus a target organism in antifouling research. After being released from adults, the swimming nauplius undertakes six molting cycles and then transforms into a cyprid. Using paired antennules, a competent cyprid actively explores and selects a suitable substratum for attachment and metamorphosis (collectively known as settlement). This selection process involves the reception of exogenous signals and subsequent endogenous signal transduction. To investigate the involvement of nitric oxide (NO) and cyclic GMP (cGMP) during larval settlement of B. amphitrite, we examined the effects of an NO donor and an NO scavenger, two nitric oxide synthase (NOS) inhibitors and a soluble guanylyl cyclase (sGC) inhibitor on settling cyprids. We found that the NO donor sodium nitroprusside (SNP) inhibited larval settlement in a dose-dependent manner. In contrast, both the NO scavenger carboxy-PTIO and the NOS inhibitors aminoguanidine hemisulfate (AGH) and S-methylisothiourea sulfate (SMIS) significantly accelerated larval settlement. Suppression of the downstream guanylyl cyclase (GC) activity using a GC-selective inhibitor ODQ could also significantly accelerate larval settlement. Interestingly, the settlement inhibition effects of SNP could be attenuated by ODQ at all concentrations tested. In the developmental expression profiling of NOS and sGC, the lowest expression of both genes was detected in the cyprid stage, a crucial stage for the larval decision to attach and metamorphose. In summary, we concluded that NO regulates larval settlement via mediating downstream cGMP signaling.

  3. Updating the Wnt pathways

    Science.gov (United States)

    Yu, Jia; Virshup, David M.

    2014-01-01

    In the three decades since the discovery of the Wnt1 proto-oncogene in virus-induced mouse mammary tumours, our understanding of the signalling pathways that are regulated by the Wnt proteins has progressively expanded. Wnts are involved in an complex signalling network that governs multiple biological processes and cross-talk with multiple additional signalling cascades, including the Notch, FGF (fibroblast growth factor), SHH (Sonic hedgehog), EGF (epidermal growth factor) and Hippo pathways. The Wnt signalling pathway also illustrates the link between abnormal regulation of the developmental processes and disease manifestation. Here we provide an overview of Wnt-regulated signalling cascades and highlight recent advances. We focus on new findings regarding the dedicated Wnt production and secretion pathway with potential therapeutic targets that might be beneficial for patients with Wnt-related diseases. PMID:25208913

  4. Developmental diversity in free-living flatworms

    Directory of Open Access Journals (Sweden)

    Martín-Durán José

    2012-03-01

    Full Text Available Abstract Flatworm embryology has attracted attention since the early beginnings of comparative evolutionary biology. Considered for a long time the most basal bilaterians, the Platyhelminthes (excluding Acoelomorpha are now robustly placed within the Spiralia. Despite having lost their relevance to explain the transition from radially to bilaterally symmetrical animals, the study of flatworm embryology is still of great importance to understand the diversification of bilaterians and of developmental mechanisms. Flatworms are acoelomate organisms generally with a simple centralized nervous system, a blind gut, and lacking a circulatory organ, a skeleton and a respiratory system other than the epidermis. Regeneration and asexual reproduction, based on a totipotent neoblast stem cell system, are broadly present among different groups of flatworms. While some more basally branching groups - such as polyclad flatworms - retain the ancestral quartet spiral cleavage pattern, most flatworms have significantly diverged from this pattern and exhibit unique strategies to specify the common adult body plan. Most free-living flatworms (i.e. Platyhelminthes excluding the parasitic Neodermata are directly developing, whereas in polyclads, also indirect developers with an intermediate free-living larval stage and subsequent metamorphosis are found. A comparative study of developmental diversity may help understanding major questions in evolutionary biology, such as the evolution of cleavage patterns, gastrulation and axial specification, the evolution of larval types, and the diversification and specialization of organ systems. In this review, we present a thorough overview of the embryonic development of the different groups of free-living (turbellarian platyhelminths, including the Catenulida, Macrostomorpha, Polycladida, Lecithoepitheliata, Proseriata, Bothrioplanida, Rhabdocoela, Fecampiida, Prolecithophora and Tricladida, and discuss their main features

  5. Helminths parasitizing larval fish from Pantanal, Brazil.

    Science.gov (United States)

    Lacerda, A C F; Santin, M; Takemoto, R M; Pavanelli, G C; Bialetzki, A; Tavernari, F C

    2009-03-01

    Fish larvae of 'corvinas' (Pachyurus bonariensis and Plagioscion ternetzi) from Sinhá Mariana Lagoon, Mato Grosso State, were collected from March 2000 to March 2004, in order to determine the parasitic fauna of fishes. Larvae from the two species were parasitized by the same endoparasites: Contracaecum sp. Type 2 (larvae) (Nematoda: Anisakidae) in the mesentery and Neoechinorhynchus (Neoechinorhynchus) paraguayensis (Acanthocephala: Neoechinorhynchidae) in the stomach and the terminal portion of the intestine. Statistical analysis showed that there was a significant positive correlation between the standard length of hosts and the abundance of acanthocephalans and nematodes, and that the prevalence of nematodes presented a significant positive correlation with the standard length of the two species of hosts, indicating the presence of a cumulative process of infection. The present study constitutes the first record of nematodes and acanthocephalans parasitizing larval fish, as well as the first record of endoparasites in fish larvae in Brazil. In addition, it lists a new locality and two species of hosts for Contracaecum sp. Type 2 (larva) and N. (N.) paraguayensis.

  6. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  7. Assessment of sampling mortality of larval fishes

    International Nuclear Information System (INIS)

    Cada, G.F.; Hergenrader, G.L.

    1978-01-01

    A study was initiated to assess the mortality of larval fishes that were entrained in the condenser cooling systems of two nuclear power plants on the Missouri River in Nebraska. High mortalities were observed not only in the discharge collections but also in control samples taken upriver from the plants where no entrainment effects were possible. As a result, entrainment mortality generally could not be demonstrated. A technique was developed which indicated that (1) a significant portion of the observed mortality above the power plants was the result of net-induced sampling mortality, and (2) a direct relationship existed between observed mortality and water velocity in the nets when sampling at the control sites, which was described by linear regression equations. When these equations were subsequently used to remove the effects of wide differences in sampling velocities between control and discharge collections, significant entrainment mortality was noted in all cases. The equations were also used to derive estimates of the natural mortality of ichthyoplankton in this portion of the Missouri River

  8. The Domain of Developmental Psychopathology.

    Science.gov (United States)

    Sroufe, L. Alan; Rutter, Michael

    1984-01-01

    Describes how developmental psychopathology differs from related disciplines, including abnormal psychology, psychiatry, clinical child psychology, and developmental psychology. Points out propositions underlying a developmental perspective and discusses implications for research in developmental psychopathology. (Author/RH)

  9. Sandeel ( Ammodytes marinus ) larval transport patterns in the North Sea from an individual-based hydrodynamic egg and larval model

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Jensen, Henrik; Mosegaard, Henrik

    2008-01-01

    We have calculated a time series of larval transport indices for the central and southern North Sea covering 1970-2004, using a combined three-dimensional hydrodynamic and individual-based modelling framework for studying sandeel (Ammodytes marinus) eggs, larval transport, and growth. The egg phase...... is modelled by a stochastic, nonlinear degree-day model describing the extended hatch period. The larval growth model is parameterized by individually back-tracking the local physical environment of larval survivors from their catch location and catch time. Using a detailed map of sandeel habitats...... analyzed, and we introduce novel a scheme to quantify direct and indirect connectivity on equal footings in terms of an interbank transit time scale....

  10. Heart Performance Determination by Visualization in Larval Fishes: Influence of Alternative Models for Heart Shape and Volume

    Directory of Open Access Journals (Sweden)

    Prescilla Perrichon

    2017-07-01

    Full Text Available Understanding cardiac function in developing larval fishes is crucial for assessing their physiological condition and overall health. Cardiac output measurements in transparent fish larvae and other vertebrates have long been made by analyzing videos of the beating heart, and modeling this structure using a conventional simple prolate spheroid shape model. However, the larval fish heart changes shape during early development and subsequent maturation, but no consideration has been made of the effect of different heart geometries on cardiac output estimation. The present study assessed the validity of three different heart models (the “standard” prolate spheroid model as well as a cylinder and cone tip + cylinder model applied to digital images of complete cardiac cycles in larval mahi-mahi and red drum. The inherent error of each model was determined to allow for more precise calculation of stroke volume and cardiac output. The conventional prolate spheroid and cone tip + cylinder models yielded significantly different stroke volume values at 56 hpf in red drum and from 56 to 104 hpf in mahi. End-diastolic and stroke volumes modeled by just a simple cylinder shape were 30–50% higher compared to the conventional prolate spheroid. However, when these values of stroke volume multiplied by heart rate to calculate cardiac output, no significant differences between models emerged because of considerable variability in heart rate. Essentially, the conventional prolate spheroid shape model provides the simplest measurement with lowest variability of stroke volume and cardiac output. However, assessment of heart function—especially if stroke volume is the focus of the study—should consider larval heart shape, with different models being applied on a species-by-species and developmental stage-by-stage basis for best estimation of cardiac output.

  11. Genetic and evolutionary analysis of the Drosophila larval neuromuscular junction

    Science.gov (United States)

    Campbell, Megan

    Although evolution of brains and behaviors is of fundamental biological importance, we lack comprehensive understanding of the general principles governing these processes or the specific mechanisms and molecules through which the evolutionary changes are effected. Because synapses are the basic structural and functional units of nervous systems, one way to address these problems is to dissect the genetic and molecular pathways responsible for morphological evolution of a defined synapse. I have undertaken such an analysis by examining morphology of the larval neuromuscular junction (NMJ) in wild caught D. melanogaster as well as in over 20 other species of Drosophila. Whereas variation in NMJ morphology within a species is limited, I discovered a surprisingly extensive variation among different species. Compared with evolution of other morphological traits, NMJ morphology appears to be evolving very rapidly. Moreover, my data indicate that natural selection rather than genetic drift is primarily responsible for evolution of NMJ morphology. To dissect underlying molecular mechanisms that may govern NMJ growth and evolutionary divergence, I focused on a naturally occurring variant in D. melanogaster that causes NMJ overgrowth. I discovered that the variant mapped to Mob2, a gene encoding a kinase adapter protein originally described in yeast as a member of the Mitotic Exit Network (MEN). I have subsequently examined mutations in the Drosophila orthologs of all the core components of the yeast MEN and found that all of them function as part of a common pathway that acts presynaptically to negatively regulate NMJ growth. As in the regulation of yeast cytokinesis, these components of the MEN appear to act ultimately by regulating actin dynamics during the process of bouton growth and division. These studies have thus led to the discovery of an entirely new role for the MEN---regulation of synaptic growth---that is separate from its function in cell division. This work

  12. Developmental exposure to triclosan alters microbiota community structure and locomotor activity in larval zebrafish

    Science.gov (United States)

    Growing evidence indicates that host-associated microbiota modify the toxicokinetics and/or toxicodynamics of environmental chemicals; however, current risk assessment methods do not consider interactions between microbiota and chemical toxicity. We previously reported that micro...

  13. Temperature, paternity and asynchronous hatching influence early developmental characteristics of larval Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Dahlke, Flemming T.; Butts, Ian A.E.

    2014-01-01

    Offspring, especially during early development, are influenced by both intrinsic properties endowed to them by their parents, extrinsic environmental factors as well as the interplay between genes and the environment. We investigated the effects of paternity (P), temperature (T), and asynchronous...

  14. Tissue-specific transcriptome profiling of Plutella xylostella third instar larval midgut.

    Science.gov (United States)

    Xie, Wen; Lei, Yanyuan; Fu, Wei; Yang, Zhongxia; Zhu, Xun; Guo, Zhaojiang; Wu, Qingjun; Wang, Shaoli; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2012-01-01

    The larval midgut of diamondback moth, Plutella xylostella, is a dynamic tissue that interfaces with a diverse array of physiological and toxicological processes, including nutrient digestion and allocation, xenobiotic detoxification, innate and adaptive immune response, and pathogen defense. Despite its enormous agricultural importance, the genomic resources for P. xylostella are surprisingly scarce. In this study, a Bt resistant P. xylostella strain was subjected to the in-depth transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes in the P. xylostella larval midgut. Using Illumina deep sequencing, we obtained roughly 40 million reads containing approximately 3.6 gigabases of sequence data. De novo assembly generated 63,312 ESTs with an average read length of 416 bp, and approximately half of the P. xylostella sequences (45.4%, 28,768) showed similarity to the non-redundant database in GenBank with a cut-off E-value below 10(-5). Among them, 11,092 unigenes were assigned to one or multiple GO terms and 16,732 unigenes were assigned to 226 specific pathways. In-depth analysis identified genes putatively involved in insecticide resistance, nutrient digestion, and innate immune defense. Besides conventional detoxification enzymes and insecticide targets, novel genes, including 28 chymotrypsins and 53 ABC transporters, have been uncovered in the P. xylostella larval midgut transcriptome; which are potentially linked to the Bt toxicity and resistance. Furthermore, an unexpectedly high number of ESTs, including 46 serpins and 7 lysozymes, were predicted to be involved in the immune defense.As the first tissue-specific transcriptome analysis of P. xylostella, this study sheds light on the molecular understanding of insecticide resistance, especially Bt resistance in an agriculturally important insect pest, and lays the foundation for future functional genomics research. In addition, current

  15. Tissue-Specific Transcriptome Profiling of Plutella Xylostella Third Instar Larval Midgut

    Science.gov (United States)

    Xie, Wen; Lei, Yanyuan; Fu, Wei; Yang, Zhongxia; Zhu, Xun; Guo, Zhaojiang; Wu, Qingjun; Wang, Shaoli; Xu, Baoyun; Zhou, Xuguo; Zhang, Youjun

    2012-01-01

    The larval midgut of diamondback moth, Plutella xylostella, is a dynamic tissue that interfaces with a diverse array of physiological and toxicological processes, including nutrient digestion and allocation, xenobiotic detoxification, innate and adaptive immune response, and pathogen defense. Despite its enormous agricultural importance, the genomic resources for P. xylostella are surprisingly scarce. In this study, a Bt resistant P. xylostella strain was subjected to the in-depth transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes in the P. xylostella larval midgut. Using Illumina deep sequencing, we obtained roughly 40 million reads containing approximately 3.6 gigabases of sequence data. De novo assembly generated 63,312 ESTs with an average read length of 416bp, and approximately half of the P. xylostella sequences (45.4%, 28,768) showed similarity to the non-redundant database in GenBank with a cut-off E-value below 10-5. Among them, 11,092 unigenes were assigned to one or multiple GO terms and 16,732 unigenes were assigned to 226 specific pathways. In-depth analysis indentified genes putatively involved in insecticide resistance, nutrient digestion, and innate immune defense. Besides conventional detoxification enzymes and insecticide targets, novel genes, including 28 chymotrypsins and 53 ABC transporters, have been uncovered in the P. xylostella larval midgut transcriptome; which are potentially linked to the Bt toxicity and resistance. Furthermore, an unexpectedly high number of ESTs, including 46 serpins and 7 lysozymes, were predicted to be involved in the immune defense. As the first tissue-specific transcriptome analysis of P. xylostella, this study sheds light on the molecular understanding of insecticide resistance, especially Bt resistance in an agriculturally important insect pest, and lays the foundation for future functional genomics research. In addition, current

  16. Bioactivity of plant extracts on the larval and pupal stages of Aedes aegypti (Diptera, Culicidea

    Directory of Open Access Journals (Sweden)

    Lafayette Pereira Candido

    2013-07-01

    Full Text Available Introduction Aedes aegypti is responsible for the transmission of the dengue and yellow fever viruses. This study evaluated the effects of extracts from Cnidosculos phyllacanthus, Ricinus communis, and Coutarea hexandra on the developmental periods of A.aegypti larvae and pupae. Crude extracts of C. phyllacanthus and C. hexandra and oil from R. communis and C. phyllacanthus were used. Methods Bioassays of the larvicidal and pupicidal effects of these products at different concentrations and times of exposure were evaluated. The lethal and sublethal effects were determined using different concentrations in larvicidal tests. Mortality data were evaluated by Probit analysis to determine the LC50 and LC90 values. Results The vegetable oils from C. phyllacanthus and R. communis demonstrated greater efficiency for larval control with an LC50=0.28µl/mL and an LC90=1.48µl/mL and LC50=0.029µl/mL and a LC90=0.26µl/mL, respectively. In pupal tests toxic effects for all insects were verified after exposure to the products at significant LC50 and LC90 values for 24 and 48h. The effects of sublethal concentrations of C. phyllacanthus (oil were more effective on the insects. Conclusions The vegetables oils from C. phyllacanthus and R. communis demonstrated greater potential from the control of different developmental periods in the life cycle of this insect.

  17. Developmental plasticity: re-conceiving the genotype.

    Science.gov (United States)

    Sultan, Sonia E

    2017-10-06

    In recent decades, the phenotype of an organism (i.e. its traits and behaviour) has been studied as the outcome of a developmental 'programme' coded in its genotype. This deterministic view is implicit in the Modern Synthesis approach to adaptive evolution as a sorting process among genetic variants. Studies of developmental pathways have revealed that genotypes are in fact differently expressed depending on environmental conditions. Accordingly, the genotype can be understood as a repertoire of potential developmental outcomes or norm of reaction. Reconceiving the genotype as an environmental response repertoire rather than a fixed developmental programme leads to three critical evolutionary insights. First, plastic responses to specific conditions often comprise functionally appropriate trait adjustments, resulting in an individual-level, developmental mode of adaptive variation. Second, because genotypes are differently expressed depending on the environment, the genetic diversity available to natural selection is itself environmentally contingent. Finally, environmental influences on development can extend across multiple generations via cytoplasmic and epigenetic factors transmitted to progeny individuals, altering their responses to their own, immediate environmental conditions and, in some cases, leading to inherited but non-genetic adaptations. Together, these insights suggest a more nuanced understanding of the genotype and its evolutionary role, as well as a shift in research focus to investigating the complex developmental interactions among genotypes, environments and previous environments.

  18. Effect of thermal shock on developmental stages of estuarine fish. Final report

    International Nuclear Information System (INIS)

    Dean, J.M.

    1978-12-01

    Physiological data and ecological data show that the few estuarine spawners have a higher thermal tolerance in the embryonic and larval stages than do the freshwater, coastal, or oceanic spawning species. However, since all three groups (freshwater, estuarine, and oceanic spawners) occupy the estuary and coastal waters at different times of the year, knowledge of their physiology and ecology at different developmental or life cycle stages is critical for estuarine management decisions

  19. Larval dispersal in three coral reef decapod species: Influence of larval duration on the metapopulation structure

    Science.gov (United States)

    Zavala-Hidalgo, Jorge; Allende-Arandía, Eugenia; Hermoso-Salazar, Margarita

    2018-01-01

    Most coral-associated decapod species have non-migratory adult populations and depend on their planktonic larvae for dispersal. This study examined the metapopulation structure of three decapod species with different pelagic larval duration (PLD) from twelve coral reef complexes of the Gulf of Mexico. The dispersion of larvae was analyzed through the use of a realistic numerical simulation of the Gulf of Mexico with the Hybrid Coordinate Ocean Model. To study the transport and dispersion of particles in near-surface waters, a particle-tracking subroutine was run using as input the currents from the model. The simulation consisted of the launch of 100 passive particles (virtual larvae) every 24 hours from each reef throughout five years, and tracked for as long as 210 days. Results indicated that species with a short PLD, Mithraculus sculptus (PLD 8‒13 days), had a weak connection among the reefs, but higher self-recruitment, especially on the narrow western shelf. The species with a longer PLD, Dromia erythropus (28‒30 days), had a stronger connection among neighboring reefs (< 300 km). Finally, the species with an even longer PLD, Stenopus hispidus (123‒210 days), had a wider potential distribution than the other species. Circulation on synoptic, seasonal and interannual scales had differential effects on the larval dispersal of each species. The metapopulation structure of M. sculptus and D. erythropus seemed to combine features of the non-equilibrium and the patchy models, whereas that of S. hispidus presumably fit to a patchy model. These findings support previous observations that indicate that species with longer PLD tend to occupy larger areas than species with short PLD, although recruitment of juveniles to the adult populations will also depend on other factors, such as the availability of suitable habitats and the ability to colonize them. PMID:29558478

  20. Reproductive and developmental toxicology

    National Research Council Canada - National Science Library

    Gupta, Ramesh C

    2011-01-01

    .... Reproductive and Developmental Toxicology is a comprehensive and authoritative resource providing the latest literature enriched with relevant references describing every aspect of this area of science...

  1. Effects of two stressors on amphibian larval development.

    Science.gov (United States)

    Stark, Karolina; Scott, David E; Tsyusko, Olga; Coughlin, Daniel P; Hinton, Thomas G

    2012-05-01

    In parallel with a renewed interest in nuclear power and its possible environmental impacts, a new environmental radiation protection system calls for environmental indicators of radiological stress. However, because environmental stressors seldom occur alone, this study investigated the combined effects of an ecological stressor (larval density) and an anthropogenic stressor (ionizing radiation) on amphibians. Scaphiopus holbrookii tadpoles reared at different larval densities were exposed to four low irradiation dose rates (0.13, 2.4, 21, and 222 mGy d(-1)) from (137)Cs during the sensitive period prior to and throughout metamorphosis. Body size at metamorphosis and development rate served as fitness correlates related to population dynamics. Results showed that increased larval density decreased body size but did not affect development rate. Low dose rate radiation had no impact on either endpoint. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Reduce, reuse, recycle - Developmental signals in spinal cord regeneration.

    Science.gov (United States)

    Cardozo, Marcos Julian; Mysiak, Karolina S; Becker, Thomas; Becker, Catherina G

    2017-12-01

    Anamniotes, fishes and amphibians, have the capacity to regenerate spinal cord tissue after injury, generating new neurons that mature and integrate into the spinal circuitry. Elucidating the molecular signals that promote this regeneration is a fundamental question in regeneration research. Model systems, such as salamanders and larval and adult zebrafish are used to analyse successful regeneration. This shows that many developmental signals, such as Notch, Hedgehog (Hh), Bone Morphogenetic Protein (BMP), Wnt, Fibroblast Growth Factor (FGF), Retinoic Acid (RA) and neurotransmitters are redeployed during regeneration and activate resident spinal progenitor cells. Here we compare the roles of these signals in spinal cord development and regeneration of the much larger and fully patterned adult spinal cord. Understanding how developmental signalling systems are reactivated in successfully regenerating species may ultimately lead to ways to reactivate similar systems in mammalian progenitor cells, which do not show neurogenesis after spinal injury. Copyright © 2017. Published by Elsevier Inc.

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

    Science.gov (United States)

    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.

  4. Polycystic echinococcosis in Colombia: the larval cestodes in infected rodents.

    Science.gov (United States)

    Morales, G A; Guzman, V H; Wells, E A; Angel, D

    1979-07-01

    Described are the characteristics of the polycystic larval cestodes found in an endemic area of echinococcosis in the Easter Plains of Colombia and the tissue reaction evoked in infected rodents. Of 848 free-ranging animals examined, polycystic hydatids were found in 44/93 Cuniculus paca and 1/369 Proechimys sp. None of 20 Dasyprocta fuliginosa examined was infected, but hunters provided a heart with hydatid cysts and information about two additional animals with infected livers. Recognition of an endemic area of polycystic echinococcosis provides a means to investigate the life cycle of the parasites and to study the histogenesis of the larval cestodes in susceptible laboratory animals.

  5. The neural basis of visual behaviors in the larval zebrafish.

    Science.gov (United States)

    Portugues, Ruben; Engert, Florian

    2009-12-01

    We review visually guided behaviors in larval zebrafish and summarise what is known about the neural processing that results in these behaviors, paying particular attention to the progress made in the last 2 years. Using the examples of the optokinetic reflex, the optomotor response, prey tracking and the visual startle response, we illustrate how the larval zebrafish presents us with a very promising model vertebrate system that allows neurocientists to integrate functional and behavioral studies and from which we can expect illuminating insights in the near future. Copyright 2009 Elsevier Ltd. All rights reserved.

  6. Organogénesis durante el periodo larval en peces

    OpenAIRE

    Zavala-Leal, I; Dumas, Silvie; Peña Martínez, Renato

    2011-01-01

    La presencia de un periodo larval caracteriza a los peces con ontogenia indirecta. Este periodo de desarrollo implica una serie de transformaciones encaminadas a la adquisición de las características biológicas y ecológicas propias de la especie; y en muchos casos culmina con cambios de distribución y hábitos alimenticios. El periodo larval incluye cuatro estadios de desarrollo: larva vitelina, larva pre-flexión, larva flexión y larva post-flexión. Cada estadio de desarrollo presenta caracter...

  7. rigor mortis encodes a novel nuclear receptor interacting protein required for ecdysone signaling during Drosophila larval development.

    Science.gov (United States)

    Gates, Julie; Lam, Geanette; Ortiz, José A; Losson, Régine; Thummel, Carl S

    2004-01-01

    Pulses of the steroid hormone ecdysone trigger the major developmental transitions in Drosophila, including molting and puparium formation. The ecdysone signal is transduced by the EcR/USP nuclear receptor heterodimer that binds to specific response elements in the genome and directly regulates target gene transcription. We describe a novel nuclear receptor interacting protein encoded by rigor mortis (rig) that is required for ecdysone responses during larval development. rig mutants display defects in molting, delayed larval development, larval lethality, duplicated mouth parts, and defects in puparium formation--phenotypes that resemble those seen in EcR, usp, E75A and betaFTZ-F1 mutants. Although the expression of these nuclear receptor genes is essentially normal in rig mutant larvae, the ecdysone-triggered switch in E74 isoform expression is defective. rig encodes a protein with multiple WD-40 repeats and an LXXLL motif, sequences that act as specific protein-protein interaction domains. Consistent with the presence of these elements and the lethal phenotypes of rig mutants, Rig protein interacts with several Drosophila nuclear receptors in GST pull-down experiments, including EcR, USP, DHR3, SVP and betaFTZ-F1. The ligand binding domain of betaFTZ-F1 is sufficient for this interaction, which can occur in an AF-2-independent manner. Antibody stains reveal that Rig protein is present in the brain and imaginal discs of second and third instar larvae, where it is restricted to the cytoplasm. In larval salivary gland and midgut cells, however, Rig shuttles between the cytoplasm and nucleus in a spatially and temporally regulated manner, at times that correlate with the major lethal phase of rig mutants and major switches in ecdysone-regulated gene expression. Taken together, these data indicate that rig exerts essential functions during larval development through gene-specific effects on ecdysone-regulated transcription, most likely as a cofactor for one or more

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

    NARCIS (Netherlands)

    Bukhari, S.T.; Middelman, A.; Koenraadt, C.J.M.; Takken, W.; Knols, B.G.J.

    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

  9. Embryonic, Larval, and Early Juvenile Development of the Tropical Sea Urchin, Salmacis sphaeroides (Echinodermata: Echinoidea

    Directory of Open Access Journals (Sweden)

    M. Aminur Rahman

    2012-01-01

    Full Text Available Salmacis sphaeroides (Linnaeus, 1758 is one of the regular echinoids, occuring in the warm Indo-West Pacific, including Johor Straits, between Malaysia and Singapore. In order to investigate the developmental basis of morphological changes in embryos and larvae, we documented the ontogeny of S. sphaeroides in laboratory condition. Gametes were obtained from adult individuals by 0.5 M KCl injection into the coelomic cavity. Fertilization rate at limited sperm concentration (10−5 dilution was 96.6±1.4% and the resulting embryos were reared at 24°C. First cleavage (2-cell, 4-cell, 8-cell, 16-cell, 32-cell, and multicell (Morulla stages were achieved 01.12, 02.03, 02.28, 02.51, 03.12, and 03.32 h postfertilization. Ciliated blastulae with a mean length of 174.72±4.43 μm hatched 08.45 h after sperm entry. The gastrulae formed 16.15 h postfertilization and the archenteron elongated constantly while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larva started to feed unicellular algae in 2 d, grew continuously, and finally attained metamorphic competence in 35 d after fertilization. Metamorphosis took approximately 1 h 30 min from attachment to the complete resorption of larval tissues and the development of complete juvenile structure with adult spines, extended tubefeet and well-developed pedicellaria, the whole event of which usually took place within 1 d postsettlement. This study represents the first successful investigation on embryonic, larval, and early juvenile development of S. sphaeroides. The findings would greatly be helpful towards the understanding of ontogeny and life-history strategies, which will facilitate us to develop the breeding, seed production, and culture techniques of sea urchins in captive condition.

  10. Bortezomib initiates endoplasmic reticulum stress, elicits autophagy and death in Echinococcus granulosus larval stage

    Science.gov (United States)

    Nicolao, María Celeste; Loos, Julia A.; Rodriguez Rodrigues, Christian; Beas, Viviana

    2017-01-01

    Cystic echinococcosis (CE) is a worldwide distributed helminthic zoonosis caused by Echinococcus granulosus. Benzimidazole derivatives are currently the only drugs for chemotherapeutic treatment of CE. However, their low efficacy and the adverse effects encourage the search for new therapeutic targets. We evaluated the in vitro efficacy of Bortezomib (Bz), a proteasome inhibitor, in the larval stage of the parasite. After 96 h, Bz showed potent deleterious effects at a concentration of 5 μM and 0.5 μM in protoscoleces and metacestodes, respectively (P Echinococcus cell viability, we evaluated the efficacy of Bz in combination with rapamycin and a synergistic cytotoxic effect on protoscolex viability was observed when both drugs were used together. In conclusion, our findings demonstrated that Bz induced endoplasmic reticulum stress, autophagy and subsequent death allowing to identify unstudied parasite-host pathways that could provide a new insight for control of parasitic diseases. PMID:28817601

  11. Bortezomib initiates endoplasmic reticulum stress, elicits autophagy and death in Echinococcus granulosus larval stage.

    Directory of Open Access Journals (Sweden)

    María Celeste Nicolao

    Full Text Available Cystic echinococcosis (CE is a worldwide distributed helminthic zoonosis caused by Echinococcus granulosus. Benzimidazole derivatives are currently the only drugs for chemotherapeutic treatment of CE. However, their low efficacy and the adverse effects encourage the search for new therapeutic targets. We evaluated the in vitro efficacy of Bortezomib (Bz, a proteasome inhibitor, in the larval stage of the parasite. After 96 h, Bz showed potent deleterious effects at a concentration of 5 μM and 0.5 μM in protoscoleces and metacestodes, respectively (P < 0.05. After 48 h of exposure to this drug, it was triggered a mRNA overexpression of chaperones (Eg-grp78 and Eg-calnexin and of Eg-ire2/Eg-xbp1 (the conserved UPR pathway branch in protoscoleces. No changes were detected in the transcriptional expression of chaperones in Bz-treated metacestodes, thus allowing ER stress to be evident and viability to highly decrease in comparison with protoscoleces. We also found that Bz treatment activated the autophagic process in both larval forms. These facts were evidenced by the increase in the amount of transcripts of the autophagy related genes (Eg-atg6, Eg-atg8, Eg-atg12, Eg-atg16 together with the increase in Eg-Atg8-II detected by western blot and by in toto immunofluorescence labeling. It was further confirmed by direct observation of autophagic structures by electronic microscopy. Finally, in order to determine the impact of autophagy induction on Echinococcus cell viability, we evaluated the efficacy of Bz in combination with rapamycin and a synergistic cytotoxic effect on protoscolex viability was observed when both drugs were used together. In conclusion, our findings demonstrated that Bz induced endoplasmic reticulum stress, autophagy and subsequent death allowing to identify unstudied parasite-host pathways that could provide a new insight for control of parasitic diseases.

  12. Diel and lunar variations in larval supply to Malindi Marine Park ...

    African Journals Online (AJOL)

    Understanding larval ecology and the mechanisms used in dispersal and habitat selection helps to better understand the population dynamics of coral reef communities. However, few studies have examined patterns of larval supply to reefs sites especially in the WIO region. Temporal patterns of fish larval occurrence in ...

  13. File list: InP.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.10.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.10.AllAg.Larval_brain.bed ...

  14. File list: His.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.50.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.50.AllAg.Larval_brain.bed ...

  15. File list: ALL.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.50.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.50.AllAg.Larval_brain.bed ...

  16. File list: InP.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.20.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.20.AllAg.Larval_brain.bed ...

  17. Vegetative substrates used by larval northern pike in Rainy and Kabetogama Lakes, Minnesota

    Science.gov (United States)

    Anne L. Timm; Rodney B. Pierce

    2015-01-01

    Our objective was to identify characteristics of aquatic vegetative communities used as larval northern pike nursery habitat in Rainy and Kabetogama lakes, glacial shield reservoirs in northern Minnesota. Quatrefoil light traps fished at night were used to sample larval northern pike in 11 potential nursery areas. Larval northern pike were most commonly sampled among...

  18. File list: InP.Lar.50.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.50.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.50.AllAg.Larval_brain.bed ...

  19. File list: ALL.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.20.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426944,SRX14...26943,SRX1426945,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.20.AllAg.Larval_brain.bed ...

  20. File list: ALL.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.05.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426946,SRX1426943 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.05.AllAg.Larval_brain.bed ...

  1. File list: ALL.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Lar.10.AllAg.Larval_brain dm3 All antigens Larvae Larval brain SRX1426945,SRX14...26944,SRX1426943,SRX1426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Lar.10.AllAg.Larval_brain.bed ...

  2. File list: InP.Lar.05.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Lar.05.AllAg.Larval_brain dm3 Input control Larvae Larval brain SRX1426944,SRX1...426946 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Lar.05.AllAg.Larval_brain.bed ...

  3. File list: His.Lar.10.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.10.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426945,SRX1426943... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.10.AllAg.Larval_brain.bed ...

  4. File list: His.Lar.20.AllAg.Larval_brain [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Lar.20.AllAg.Larval_brain dm3 Histone Larvae Larval brain SRX1426943,SRX1426945... http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Lar.20.AllAg.Larval_brain.bed ...

  5. Integrated mosquito larval source management reduces larval numbers in two highland villages in western Kenya

    Directory of Open Access Journals (Sweden)

    Imbahale Susan S

    2012-05-01

    Full Text Available Abstract Background In western Kenya, malaria remains one of the major health problems and its control remains an important public health measure. Malaria control is by either use of drugs to treat patients infected with malaria parasites or by controlling the vectors. Vector control may target the free living adult or aquatic (larval stages of mosquito. The most commonly applied control strategies target indoor resting mosquitoes. However, because mosquitoes spend a considerable time in water, targeting the aquatic stages can complement well with existing adult control measures. Methods Larval source management (LSM of malaria vectors was examined in two villages i.e. Fort Ternan and Lunyerere, with the aim of testing strategies that can easily be accessed by the affected communities. Intervention strategies applied include environmental management through source reduction (drainage of canals, land levelling or by filling ditches with soil, habitat manipulation (by provision of shading from arrow root plant, application of Bacillus thuringiensis var israelensis (Bti and the use of predatory fish, Gambusia affinis. The abundance of immature stages of Anopheles and Culex within intervention habitats was compared to that within non-intervention habitats. Results The findings show that in Fort Ternan no significant differences were observed in the abundance of Anopheles early and late instars between intervention and non-intervention habitats. In Lunyerere, the abundance of Anopheles early instars was fifty five times more likely to be present within non-intervention habitats than in habitats under drainage. No differences in early instars abundance were observed between non-intervention and habitats applied with Bti. However, late instars had 89 % and 91 % chance of being sampled from non-intervention rather than habitats under drainage and those applied with Bti respectively. Conclusion Most of these interventions were applied in habitats

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

    Science.gov (United States)

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

    2016-12-02

    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.

  7. Larval biology of the crab Rhithropanopeus harrisii (Gould): a synthesis.

    Science.gov (United States)

    Forward, Richard B

    2009-06-01

    This synthesis reviews the physiological ecology and behavior of larvae of the benthic crab Rhithropanopeus harrisii, which occurs in low-salinity areas of estuaries. Larvae are released rhythmically around the time of high tide in tidal estuaries and in the 2-h interval after sunset in nontidal estuaries. As in most subtidal crustaceans, the timing of larval release is controlled by the developing embryos, which release peptide pheromones that stimulate larval release behavior by the female to synchronize the time of egg hatching. Larvae pass through four zoeal stages and a postlarval or megalopal stage that are planktonic before metamorphosis. They are retained near the adult population by means of an endogenous tidal rhythm in vertical migration. Larvae have several safeguards against predation: they undergo nocturnal diel vertical migration (DVM) and have a shadow response to avoid encountering predators, and they bear long spines as a deterrent. Photoresponses during DVM and the shadow response are enhanced by exposure to chemical cues from the mucus of predator fishes and ctenophores. The primary visual pigment has a spectral sensitivity maximum at about 500 nm, which is typical for zooplankton and matches the ambient spectrum at twilight. Larvae can detect vertical gradients in temperature, salinity, and hydrostatic pressure, which are used for depth regulation and avoidance of adverse environmental conditions. Characteristics that are related to the larval habitat and are common to other crab larval species are considered.

  8. Basolateral Cl- channels in the larval bullfrog skin epithelium

    DEFF Research Database (Denmark)

    Hillyard, Stanley D.; Rios, K.; Larsen, Erik Hviid

    2002-01-01

    The addition of 150 U/ml nystatin to the mucosal surface of isolated skin from larval bullfrogs increases apical membrane permeability and allows a voltage clamp to be applied to the basolateral membrane. With identical Ringer's solutions bathing either side of the tissue the short-circuit curren...

  9. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands were dissected and prepared for light and polarized light microscopy, as well as for scanning and transmission electron microscopy. The results showed that silk formation starts at the middle of the 5th ...

  10. A larval hunger signal in the bumblebee Bombus terrestris

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Duchateau, Marie-Jose

    2006-01-01

    Larvae of Bombus terrestris, a pollen-storing bumblebee, are dependent on progressive provisioning by workers. We test the hypothesis that larval cuticular chemicals can act as a hunger signal. We first show with a new classical conditioning experiment, using a Y-shaped tube, that workers can...

  11. Estimation of larval density of Liriomyza sativae Blanchard (Diptera ...

    African Journals Online (AJOL)

    This study was conducted to develop sequential sampling plans to estimate larval density of Liriomyza sativae Blanchard (Diptera: Agromyzidae) at three precision levels in cucumber greenhouse. The within- greenhouse spatial patterns of larvae were aggregated. The slopes and intercepts of both Iwao's patchiness ...

  12. Hypothalamic Projections to the Optic Tectum in Larval Zebrafish

    Science.gov (United States)

    Heap, Lucy A.; Vanwalleghem, Gilles C.; Thompson, Andrew W.; Favre-Bulle, Itia; Rubinsztein-Dunlop, Halina; Scott, Ethan K.

    2018-01-01

    The optic tectum of larval zebrafish is an important model for understanding visual processing in vertebrates. The tectum has been traditionally viewed as dominantly visual, with a majority of studies focusing on the processes by which tectal circuits receive and process retinally-derived visual information. Recently, a handful of studies have shown a much more complex role for the optic tectum in larval zebrafish, and anatomical and functional data from these studies suggest that this role extends beyond the visual system, and beyond the processing of exclusively retinal inputs. Consistent with this evolving view of the tectum, we have used a Gal4 enhancer trap line to identify direct projections from rostral hypothalamus (RH) to the tectal neuropil of larval zebrafish. These projections ramify within the deepest laminae of the tectal neuropil, the stratum album centrale (SAC)/stratum griseum periventriculare (SPV), and also innervate strata distinct from those innervated by retinal projections. Using optogenetic stimulation of the hypothalamic projection neurons paired with calcium imaging in the tectum, we find rebound firing in tectal neurons consistent with hypothalamic inhibitory input. Our results suggest that tectal processing in larval zebrafish is modulated by hypothalamic inhibitory inputs to the deep tectal neuropil. PMID:29403362

  13. Study on Silkworm Bed Cleaning Frequency during Larval Growth ...

    African Journals Online (AJOL)

    Study on Silkworm Bed Cleaning Frequency during Larval Growth Period. Abiy Tilahun, Kedir Shifa, Ahmed Ibrahim, Metasebia Terefe. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/star.v4i2.5 · AJOL African ...

  14. Body shape, burst speed and escape behavior of larval anurans

    Science.gov (United States)

    Gage H. Dayton; Daniel Saenz; Kristen A. Baum; R. Brian Langerhans; Thomas J. DeWitt

    2005-01-01

    Variation in behavior, morphology and life history traits of larval anurans across predator gradients, and consequences of that variation, have been abundantly studied. Yet the functional link between morphology and burst-swimming speed is largely unknown. We conducted experiments with two divergent species of anurans, Scaphiopus holbrookii and

  15. Population dynamics and management implications of larval dispersal

    African Journals Online (AJOL)

    caused by the identified mechanism provides: (1) the basis for spatially explicit management, and (2) an explanation for the observed spatial variability in the degree of overfishing. Research on larval dispersal is also providing the information necessary to design spatially explicit management strategies involving either ...

  16. Mosquito larval habitats and public health implications in Abeokuta ...

    African Journals Online (AJOL)

    The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette.

  17. Stretch-activated cation channel from larval bullfrog skin

    DEFF Research Database (Denmark)

    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 ...

  18. The larval development and population dynamics of Derocheilocaris ...

    African Journals Online (AJOL)

    Seven larval stages of Derocheilocaris algoensis have been described and appear to be identical with those of D. typica from North America. This stresses the remarkable conservativeness of this subclass of Crustacea. The population biology of D. algoensis has been studied over 16 months and reproduction has been ...

  19. Fruit Fly Liquid Larval Diet Technology Transfer and Update

    Science.gov (United States)

    Since October 2006, USDA-ARS has been implementing a fruit fly liquid larval diet technology transfer, which has proceeded according to the following steps: (1) Recruitment of interested groups through request; (2) Establishment of the Material Transfer Agreement (MTA) with ARS; (3) Fruit fly liquid...

  20. Hypothalamic Projections to the Optic Tectum in Larval Zebrafish

    Directory of Open Access Journals (Sweden)

    Lucy A. Heap

    2018-01-01

    Full Text Available The optic tectum of larval zebrafish is an important model for understanding visual processing in vertebrates. The tectum has been traditionally viewed as dominantly visual, with a majority of studies focusing on the processes by which tectal circuits receive and process retinally-derived visual information. Recently, a handful of studies have shown a much more complex role for the optic tectum in larval zebrafish, and anatomical and functional data from these studies suggest that this role extends beyond the visual system, and beyond the processing of exclusively retinal inputs. Consistent with this evolving view of the tectum, we have used a Gal4 enhancer trap line to identify direct projections from rostral hypothalamus (RH to the tectal neuropil of larval zebrafish. These projections ramify within the deepest laminae of the tectal neuropil, the stratum album centrale (SAC/stratum griseum periventriculare (SPV, and also innervate strata distinct from those innervated by retinal projections. Using optogenetic stimulation of the hypothalamic projection neurons paired with calcium imaging in the tectum, we find rebound firing in tectal neurons consistent with hypothalamic inhibitory input. Our results suggest that tectal processing in larval zebrafish is modulated by hypothalamic inhibitory inputs to the deep tectal neuropil.

  1. Silk formation mechanisms in the larval salivary glands of Apis ...

    Indian Academy of Sciences (India)

    Unknown

    The mechanism of silk formation in Apis mellifera salivary glands, during the 5th instar, was studied. Larval salivary glands .... be used in the silk-manufacture industry. This paper analyses .... (figure 3C); and are highly birefringent (figure 3D).

  2. The role of individual variation in marine larval dispersal

    KAUST Repository

    Nanninga, Gerrit B.

    2014-12-08

    The exchange of individuals among patchy habitats plays a central role in spatial ecology and metapopulation dynamics. Dispersal is frequently observed to vary non-randomly within populations (e.g., short vs. long), indicating that variability among individuals may shape heterogeneity in patterns of connectivity. The concept of context- and condition-dependent dispersal describes the balance between the costs and benefits of dispersal that arises from the interaction of temporal and spatial landscape heterogeneity (the context) with phenotypic variability among individuals (the condition). While this hypothesis is widely accepted in terrestrial theory, it remains questionable to what extent the concept of adaptive dispersal strategies may apply to marine larval dispersal, a process that is largely determined by stochastic forces. Yet, larvae of many taxa exhibit strong navigational capabilities and there is mounting evidence of widespread intra-specific variability in biological traits that are potentially correlated with dispersal potential. While so far there are few known examples of real larval dispersal polymorphisms, intra-specifically variable dispersal strategies may be common in marine systems. Whether adaptive or not, it is becoming apparent that inter-individual heterogeneity in morphology, behavior, condition, and life history traits may have critical effects on population-level heterogeneity in dispersal. Here, we explore the eco-evolutionary causes and consequences of intrinsic and extrinsic variability on larval dispersal by synthesizing the existing literature and drawing conceptual parallels from terrestrial theory. We emphasize the potential importance of larval dispersal polymorphisms in marine population dynamics.

  3. Trisomy 21 and facial developmental instability.

    Science.gov (United States)

    Starbuck, John M; Cole, Theodore M; Reeves, Roger H; Richtsmeier, Joan T

    2013-05-01

    The most common live-born human aneuploidy is trisomy 21, which causes Down syndrome (DS). Dosage imbalance of genes on chromosome 21 (Hsa21) affects complex gene-regulatory interactions and alters development to produce a wide range of phenotypes, including characteristic facial dysmorphology. Little is known about how trisomy 21 alters craniofacial morphogenesis to create this characteristic appearance. Proponents of the "amplified developmental instability" hypothesis argue that trisomy 21 causes a generalized genetic imbalance that disrupts evolutionarily conserved developmental pathways by decreasing developmental homeostasis and precision throughout development. Based on this model, we test the hypothesis that DS faces exhibit increased developmental instability relative to euploid individuals. Developmental instability was assessed by a statistical analysis of fluctuating asymmetry. We compared the magnitude and patterns of fluctuating asymmetry among siblings using three-dimensional coordinate locations of 20 anatomic landmarks collected from facial surface reconstructions in four age-matched samples ranging from 4 to 12 years: (1) DS individuals (n = 55); (2) biological siblings of DS individuals (n = 55); 3) and 4) two samples of typically developing individuals (n = 55 for each sample), who are euploid siblings and age-matched to the DS individuals and their euploid siblings (samples 1 and 2). Identification in the DS sample of facial prominences exhibiting increased fluctuating asymmetry during facial morphogenesis provides evidence for increased developmental instability in DS faces. We found the highest developmental instability in facial structures derived from the mandibular prominence and lowest in facial regions derived from the frontal prominence. Copyright © 2013 Wiley Periodicals, Inc.

  4. Life Span Developmental Approach

    Directory of Open Access Journals (Sweden)

    Ali Eryilmaz

    2011-03-01

    Full Text Available The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of individuals with respect to developmental stages. This developmental approach suggests that scientific disciplines should not explain developmental facts only with age changes. Along with aging, cognitive, biological, and socioemotional development throughout life should also be considered to provide a reasonable and acceptable context, guideposts, and reasonable expectations for the person. There are three important subjects whom life span developmental approach deals with. These are nature vs nurture, continuity vs discontinuity, and change vs stability. Researchers using life span developmental approach gather and produce knowledge on these three most important domains of individual development with their unique scientific methodology.

  5. Remotely Sensing Larval Population Dynamics of Rice Field Anophelines

    Science.gov (United States)

    Beck, Louisa R.; Dister, Sheri W.; Wood, Byron L.; Washino, Robert K.

    1997-01-01

    The primary objective of both studies was to determine if RS and GIS techniques could be used to distinguish between high and low larval-producing rice fields in California. Results of the first study suggested that early-season green-up and proximity to livestock pastures were positively correlated with high larval abundance. Based on the early-season spectral differences between high and low larval-producing fields, it appeared that canopy development and tillering influenced mosquito habitat quality. At that time, rice fields consisted of a mixture of plants and water, a combination that allowed An. freeborni females to lay eggs in partial sunlight, protected from both predators and wind. This established a population earlier in the season than in other, 'less-green' fields where tillering and plant emergence was too minimal for ovipositioning. The study also indicated the importance of the distance that a mosquito would have to fly in order to take a bloodmeal prior to ovipositing. These associations were fully explored in an expanded study two years later. The second study confirmed the positive relationship between early season canopy development and larval abundance, and also demonstrated the relationship between abundance and distance-to-pasture. The association between greenness (as measured using NDVI), distance-to-pasture, and abundance is illustrated. The second study also indicated the siginificance of the landscape context of rice fields for larval production. Fields that included opportunities for feeding and resting within the flight range of the mosquito had higher abundances than did fields that were in a homogeneous rice area.

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

    Science.gov (United States)

    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. Copyright © 2014. Published by Elsevier Inc.

  7. Food selection in larval fruit flies: dynamics and effects on larval development

    Science.gov (United States)

    Schwarz, Sebastian; Durisko, Zachary; Dukas, Reuven

    2014-01-01

    Selecting food items and attaining a nutritionally balanced diet is an important challenge for all animals including humans. We aimed to establish fruit fly larvae ( Drosophila melanogaster) as a simple yet powerful model system for examining the mechanisms of specific hunger and diet selection. In two lab experiments with artificial diets, we found that larvae deprived of either sucrose or protein later selectively fed on a diet providing the missing nutrient. When allowed to freely move between two adjacent food patches, larvae surprisingly preferred to settle on one patch containing yeast and ignored the patch providing sucrose. Moreover, when allowed to move freely between three patches, which provided either yeast only, sucrose only or a balanced mixture of yeast and sucrose, the majority of larvae settled on the yeast-plus-sucrose patch and about one third chose to feed on the yeast only food. While protein (yeast) is essential for development, we also quantified larval success on diets with or without sucrose and show that larvae develop faster on diets containing sucrose. Our data suggest that fruit fly larvae can quickly assess major nutrients in food and seek a diet providing a missing nutrient. The larvae, however, probably prefer to quickly dig into a single food substrate for enhanced protection over achieving an optimal diet.

  8. Southeast Asia’s Democratic Developmental States and Economic Growth

    OpenAIRE

    Michael T. Rock

    2015-01-01

    How has democracy impacted growth in Southeast Asia? This question can be answered by demonstrating how political elites in Indonesia, Malaysia and Thailand crafted quite unique democratic developmental states that enabled them to provide the public goods and public policies to maintain high growth. Because of this, growth under democracy has been as high as it was during the heyday of these polities’ developmental autocracies. Moreover, as there was no single dominant pathway to the construc...

  9. Developmental changes in the metabolic network of snapdragon flowers.

    Directory of Open Access Journals (Sweden)

    Joëlle K Muhlemann

    Full Text Available Evolutionary and reproductive success of angiosperms, the most diverse group of land plants, relies on visual and olfactory cues for pollinator attraction. Previous work has focused on elucidating the developmental regulation of pathways leading to the formation of pollinator-attracting secondary metabolites such as scent compounds and flower pigments. However, to date little is known about how flowers control their entire metabolic network to achieve the highly regulated production of metabolites attracting pollinators. Integrative analysis of transcripts and metabolites in snapdragon sepals and petals over flower development performed in this study revealed a profound developmental remodeling of gene expression and metabolite profiles in petals, but not in sepals. Genes up-regulated during petal development were enriched in functions related to secondary metabolism, fatty acid catabolism, and amino acid transport, whereas down-regulated genes were enriched in processes involved in cell growth, cell wall formation, and fatty acid biosynthesis. The levels of transcripts and metabolites in pathways leading to scent formation were coordinately up-regulated during petal development, implying transcriptional induction of metabolic pathways preceding scent formation. Developmental gene expression patterns in the pathways involved in scent production were different from those of glycolysis and the pentose phosphate pathway, highlighting distinct developmental regulation of secondary metabolism and primary metabolic pathways feeding into it.

  10. A balance of Mad and Myc expression dictates larval cell apoptosis and adult stem cell development during Xenopus intestinal metamorphosis.

    Science.gov (United States)

    Okada, Morihiro; Miller, Thomas C; Wen, Luan; Shi, Yun-Bo

    2017-05-11

    The Myc/Mad/Max network has long been shown to be an important factor in regulating cell proliferation, death and differentiation in diverse cell types. In general, Myc-Max heterodimers activate target gene expression to promote cell proliferation, although excess of c-Myc can also induce apoptosis. In contrast, Mad competes against Myc to form Mad-Max heterodimers that bind to the same target genes to repress their expression and promote differentiation. The role of the Myc/Mad/Max network during vertebrate development, especially, the so-called postembryonic development, a period around birth in mammals, is unclear. Using thyroid hormone (T3)-dependent Xenopus metamorphosis as a model, we show here that Mad1 is induced by T3 in the intestine during metamorphosis when larval epithelial cell death and adult epithelial stem cell development take place. More importantly, we demonstrate that Mad1 is expressed in the larval cells undergoing apoptosis, whereas c-Myc is expressed in the proliferating adult stem cells during intestinal metamorphosis, suggesting that Mad1 may have a role in cell death during development. By using transcription activator-like effector nuclease-mediated gene-editing technology, we have generated Mad1 knockout Xenopus animals. This has revealed that Mad1 is not essential for embryogenesis or metamorphosis. On the other hand, consistent with its spatiotemporal expression profile, Mad1 knockout leads to reduced larval epithelial apoptosis but surprisingly also results in increased adult stem cell proliferation. These findings not only reveal a novel role of Mad1 in regulating developmental cell death but also suggest that a balance of Mad and Myc controls cell fate determination during adult organ development.

  11. Developmental disorders: what can be learned from cognitive neuropsychology?

    Science.gov (United States)

    Castles, Anne; Kohnen, Saskia; Nickels, Lyndsey; Brock, Jon

    2014-01-01

    The discipline of cognitive neuropsychology has been important for informing theories of cognition and describing the nature of acquired cognitive disorders, but its applicability in a developmental context has been questioned. Here, we revisit this issue, asking whether the cognitive neuropsychological approach can be helpful for exploring the nature and causes of developmental disorders and, if so, how. We outline the key features of the cognitive neuropsychological approach, and then consider how some of the major challenges to this approach from a developmental perspective might be met. In doing so, we distinguish between challenges to the methods of cognitive neuropsychology and those facing its deeper conceptual underpinnings. We conclude that the detailed investigation of patterns of both associations and dissociations, and across both developmental and acquired cases, can assist in describing the cognitive deficits within developmental disorders and in delineating possible causal pathways to their acquisition.

  12. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents.

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W

    2016-11-04

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems.

  13. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W.

    2016-01-01

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems. PMID:27811992

  14. Functions of the nonsense-mediated mRNA decay pathway in Drosophila development.

    Directory of Open Access Journals (Sweden)

    Mark M Metzstein

    2006-12-01

    Full Text Available Nonsense-mediated mRNA decay (NMD is a cellular surveillance mechanism that degrades transcripts containing premature translation termination codons, and it also influences expression of certain wild-type transcripts. Although the biochemical mechanisms of NMD have been studied intensively, its developmental functions and importance are less clear. Here, we describe the isolation and characterization of Drosophila "photoshop" mutations, which increase expression of green fluorescent protein and other transgenes. Mapping and molecular analyses show that photoshop mutations are loss-of-function mutations in the Drosophila homologs of NMD genes Upf1, Upf2, and Smg1. We find that Upf1 and Upf2 are broadly active during development, and they are required for NMD as well as for proper expression of dozens of wild-type genes during development and for larval viability. Genetic mosaic analysis shows that Upf1 and Upf2 are required for growth and/or survival of imaginal cell clones, but this defect can be overcome if surrounding wild-type cells are eliminated. By contrast, we find that the PI3K-related kinase Smg1 potentiates but is not required for NMD or for viability, implying that the Upf1 phosphorylation cycle that is required for mammalian and Caenorhabditis elegans NMD has a more limited role during Drosophila development. Finally, we show that the SV40 3' UTR, present in many Drosophila transgenes, targets the transgenes for regulation by the NMD pathway. The results establish that the Drosophila NMD pathway is broadly active and essential for development, and one critical function of the pathway is to endow proliferating imaginal cells with a competitive growth advantage that prevents them from being overtaken by other proliferating cells.

  15. Developmental checkpoints and feedback circuits time insect maturation

    DEFF Research Database (Denmark)

    Rewitz, Kim Furbo; Yamanaka, Naoki; O'Connor, Michael B.

    2013-01-01

    as external cues, to time production and release of ecdysone. Based on results discussed here, we suggest that developmental progression to adulthood is controlled by checkpoints that regulate the genetic timing program enabling it to adapt to different environmental conditions. These checkpoints utilize...... a number of signaling pathways to modulate ecdysone production in the prothoracic gland. Release of ecdysone activates an autonomous cascade of both feedforward and feedback signals that determine the duration of the ecdysone pulse at each developmental transitions. Conservation of the genetic mechanisms...... that coordinate the juvenile-adult transition suggests that insights from the fruit fly Drosophila will provide a framework for future investigation of developmental timing in metazoans....

  16. Reproductive and developmental toxicology

    National Research Council Canada - National Science Library

    Gupta, Ramesh C

    2011-01-01

    .... With a special focus on placental toxicity, this book is the only available reference to connect the three key risk stages, and is the only resource to include reproductive and developmental toxicity in domestic animals, fish, and wildlife.

  17. Developmental coordination disorder

    Science.gov (United States)

    Developmental coordination disorder can lead to: Learning problems Low self-esteem resulting from poor ability at sports and teasing by other children Repeated injuries Weight gain as a result of not wanting to participate ...

  18. Facts about Developmental Disabilities

    Science.gov (United States)

    ... play, learn, speak, behave, and move (for example, crawling and walking). Children develop at their own pace, ... person’s lifetime. Most developmental disabilities begin before a baby is born, but some can happen after birth ...

  19. Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

    Science.gov (United States)

    Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

    2016-03-01

    Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

  20. Larval and adult density of the porcellanid crab Petrolisthes armatus (Anomura: Porcellanidae in an Amazon estuary, northern Brazil

    Directory of Open Access Journals (Sweden)

    Danielly Brito de Oliveira

    2013-12-01

    Full Text Available Petrolisthes armatus (Gibbes, 1850 is a porcellanid crab with a wide geographical distribution. In the present study we analyzed variations in the abundance of P. armatus adults and larvae over an annual cycle in the Marapanim estuary of the Amazon coastal zone, in the northeastern portion of the state of Pará, Brazil. Particularly, we focused on the presence of ovigerous females and timing of larval release, with the aim of elucidating reproductive patterns in a tropical estuarine system. The mean density of P. armatus larvae (zoea I and II correlated positively with the salinity of the shallow waters of the estuary, whereas the abundance of adults correlated with the salinity registered in water samples collected from the benthic environment. There was also a significant positive correlation between larval density (zoea I and II and water temperature. Ovigerous females were captured throughout the study period, from August 2006 to July 2007, but were more abundant in June and less abundant during the rainy months, between February and May. Larvae were only present during the dry season and transition months (June to January, and were absent during the rainy season (February to May. Petrolisthes armatus reproduces throughout the year in the Marapanim estuary and all developmental stages of this species (zoeal stages I and II, megalopae and adults are found in the estuary. The results indicate that the study area is an important environment for the reproduction of this decapod.

  1. Life Span Developmental Approach

    OpenAIRE

    Ali Eryilmaz

    2011-01-01

    The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of...

  2. Immunocytochemistry and metamorphic fate of the larval nervous system of Triphyllozoon mucronatum (Ectoprocta: Gymnolaemata: Cheilostomata)

    DEFF Research Database (Denmark)

    Wanninger, Andreas; Koop, Demian; Degnan, Bernard M.

    2005-01-01

    The development of gymnolaemate Ectoprocta includes a larval stage of either the coronate or the cyphonautes type. Herein, we provide the first description of the larval neural anatomy of a coronate larva using immunocytochemical methods. We used antibodies against the neurotransmitters serotonin...... that the larval neuroanatomy and the processes that underlie the reorganization of larval organ systems during metamorphosis may vary much more among lophotrochozoan taxa than previously thought....... and FMRFamide and followed the fate of immunoreactive cells through metamorphosis. The larval serotonergic nervous system of Triphyllozoon mucronatum consists of an apical commissure, one pair of lateral axons, a coronate nerve net, an internal nerve mesh, and one pair of axons innervating the frontal organ....... FMRFamide is only found in the larval commissure and in the lateral axons. The entire serotonergic and FMRFamidergic nervous system is lost during metamorphosis and the adult neural structures form independent of the larval ones. In the postlarval zooid, both neurotransmitters are detected in the cerebral...

  3. Community College Pathways: 2013-2014 Descriptive Report

    Science.gov (United States)

    Sowers, Nicole; Yamada, Hiroyuki

    2015-01-01

    The Community College Pathways initiative consists of two pathways, Statway® and Quantway®, that accelerate post-secondary students' progress through their developmental mathematics sequence and a college-level course for credit. Launched in 2011, the Pathways have been remarkably successful, helping thousands of students achieve success in…

  4. Developmental Toxicity of Dextromethorphan in Zebrafish Embryos/Larvae

    Science.gov (United States)

    Xu, Zheng; Williams, Frederick E.; Liu, Ming-Cheh

    2012-01-01

    Dextromethorphan is widely used in over-the-counter cough and cold medications. Its efficacy and safety for infants and young children remains to be clarified. The present study was designed to use the zebrafish as a model to investigate the potential toxicity of dextromethorphan during the embryonic and larval development. Three sets of zebrafish embryos/larvae were exposed to dextromethorphan at 24 hours post fertilization (hpf), 48 hpf, and 72 hpf, respectively, during the embryonic/larval development. Compared with the 48 and 72 hpf exposure sets, the embryos/larvae in the 24 hpf exposure set showed much higher mortality rates which increased in a dose-dependent manner. Bradycardia and reduced blood flow were observed for the embryos/larvae treated with increasing concentrations of dextromethorphan. Morphological effects of dextromethorphan exposure, including yolk sac and cardiac edema, craniofacial malformation, lordosis, non-inflated swim bladder, and missing gill, were also more frequent and severe among zebrafish embryos/larvae exposed to dextromethorphan at 24 hpf. Whether the more frequent and severe developmental toxicity of dextromethorphan observed among the embryos/larvae in the 24 hpf exposure set, as compared with the 48 and 72 hpf exposure sets, is due to the developmental expression of the Phase I and Phase II enzymes involved in the metabolism of dextromethorphan remains to be clarified. A reverse transcription-polymerase chain reaction (RT-PCR) analysis, nevertheless, revealed developmental stage-dependent expression of mRNAs encoding SULT3 ST1 and SULT3 ST3, two enzymes previously shown to be capable of sulfating dextrorphan, an active metabolite of dextromethorphan. PMID:20737414

  5. Morphological and histomorphological structures of testes and ovaries in early developmental stages of the silkworm, Bombyx mori.

    Science.gov (United States)

    Sakai, Hiroki; Kirino, Yohei; Katsuma, Susumu; Aoki, Fugaku; Suzuki, Masataka G

    2016-01-01

    The gonad develops as a testis in male or an ovary in female. In the silkworm, B. mori , little is known about testis and ovary in the embryonic stages and early larval stages. In this study, we performed morphological and histomorphological observations of ovaries and testes from the late embryonic stage to the 1st instar larval stage. Results obtained with lack of accurate information on sex of examined individuals may be misleading, thus we performed phenotypic observations of gonads by utilizing sex-limited strain that enables us to easily discriminate female embryos from male ones based on those egg colors. In testis, four testicular follicles were clearly observed in the testis at the first instar larval stage, and boundary layers were formed between the testicular follicles. At the late embryonic stage, the testis consisted of four testicular follicles, while the boundary layers were still obscure. In ovary, four ovarioles were easily recognizable in the ovary at the first instar larval stage, and boundary layers were formed between the ovarioles. However, in the late embryonic stage, it was quite difficult to identify four ovarioles. Morphological characteristics were almost similar between testis and ovary in early developmental stages. Our present study demonstrates that the most reliable difference between testis and ovary in early developmental stages is the attaching point of the duct. Formation and development of the duct may be sensitive to the sex-determining signal and display sexual dimorphism in early embryonic stages.

  6. Temperature, larval diet, and density effects on development rate and survival of Aedes aegypti (Diptera: Culicidae.

    Directory of Open Access Journals (Sweden)

    Jannelle Couret

    Full Text Available Many environmental factors, biotic and abiotic interact to influence organismal development. Given the importance of Aedes aegypti as a vector of human pathogens including dengue and yellow fever, understanding the impact of environmental factors such as temperature, resource availability, and intraspecific competition during development is critical for population control purposes. Despite known associations between developmental traits and factors of diet and density, temperature has been considered the primary driver of development rate and survival. To determine the relative importance of these critical factors, wide gradients of conditions must be considered. We hypothesize that 1 diet and density, as well as temperature influence the variation in development rate and survival, 2 that these factors interact, and this interaction is also necessary to understand variation in developmental traits. Temperature, diet, density, and their two-way interactions are significant factors in explaining development rate variation of the larval stages of Ae. aegypti mosquitoes. These factors as well as two and three-way interactions are significantly associated with the development rate from hatch to emergence. Temperature, but not diet or density, significantly impacted juvenile mortality. Development time was heteroskedastic with the highest variation occurring at the extremes of diet and density conditions. All three factors significantly impacted survival curves of experimental larvae that died during development. Complex interactions may contribute to variation in development rate. To better predict variation in development rate and survival in Ae. aegypti, factors of resource availability and intraspecific density must be considered in addition, but never to the exclusion of temperature.

  7. Transgenerational developmental programming.

    Science.gov (United States)

    Aiken, Catherine E; Ozanne, Susan E

    2014-01-01

    The concept of developmental programming suggests that the early life environment influences offspring characteristics in later life, including the propensity to develop diseases such as the metabolic syndrome. There is now growing evidence that the effects of developmental programming may also manifest in further generations without further suboptimal exposure. This review considers the evidence, primarily from rodent models, for effects persisting to subsequent generations, and evaluates the mechanisms by which developmental programming may be transmitted to further generations. In particular, we focus on the potential role of the intrauterine environment in contributing to a developmentally programmed phenotype in subsequent generations. The literature was systematically searched at http://pubmed.org and http://scholar.google.com to identify published findings regarding transgenerational (F2 and beyond) developmental programming effects in human populations and animal models. Transmission of programming effects is often viewed as a form of epigenetic inheritance, either via the maternal or paternal line. Evidence exists for both germline and somatic inheritance of epigenetic modifications which may be responsible for phenotypic changes in further generations. However, there is increasing evidence for the role of both extra-genomic components of the zygote and the interaction of the developing conceptus with the intrauterine environment in propagating programming effects. The contribution of a suboptimal reproductive tract environment or maternal adaptations to pregnancy may be critical to inheritance of programming effects via the maternal line. As the effects of age exacerbate the programmed metabolic phenotype, advancing maternal age may increase the likelihood of developmental programming effects being transmitted to further generations. We suggest that developmental programming effects could be propagated through the maternal line de novo in generations

  8. Effects of moisture content of food waste on residue separation, larval growth and larval survival in black soldier fly bioconversion.

    Science.gov (United States)

    Cheng, Jack Y K; Chiu, Sam L H; Lo, Irene M C

    2017-09-01

    In order to foster sustainable management of food waste, innovations in food waste valorization technologies are crucial. Black soldier fly (BSF) bioconversion is an emerging technology that can turn food waste into high-protein fish feed through the use of BSF larvae. The conventional method of BSF bioconversion is to feed BSF larvae with food waste directly without any moisture adjustment. However, it was reported that difficulty has been experienced in the separation of the residue (larval excreta and undigested material) from the insect biomass due to excessive moisture. In addition to the residue separation problem, the moisture content of the food waste may also affect the growth and survival aspects of BSF larvae. This study aims to determine the most suitable moisture content of food waste that can improve residue separation as well as evaluate the effects of the moisture content of food waste on larval growth and survival. In this study, pre-consumer and post-consumer food waste with different moisture content (70%, 75% and 80%) was fed to BSF larvae in a temperature-controlled rotary drum reactor. The results show that the residue can be effectively separated from the insect biomass by sieving using a 2.36mm sieve, for both types of food waste at 70% and 75% moisture content. However, sieving of the residue was not feasible for food waste at 80% moisture content. On the other hand, reduced moisture content of food waste was found to slow down larval growth. Hence, there is a trade-off between the sieving efficiency of the residue and the larval growth rate. Furthermore, the larval survival rate was not affected by the moisture content of food waste. A high larval survival rate of at least 95% was achieved using a temperature-controlled rotary drum reactor for all treatment groups. The study provides valuable insights for the waste management industry on understanding the effects of moisture content when employing BSF bioconversion for food waste recycling

  9. Proteolytic activity in the adult and larval stages of the human roundworm parasite Angiostrongylus costaricensis

    Directory of Open Access Journals (Sweden)

    Karina Mastropasqua Rebello

    2012-09-01

    Full Text Available Angiostrongylus costaricensis is a nematode that causes abdominal angiostrongyliasis, a widespread human parasitism in Latin America. This study aimed to characterize the protease profiles of different developmental stages of this helminth. First-stage larvae (L1 were obtained from the faeces of infected Sigmodon hispidus rodents and third-stage larvae (L3 were collected from mollusks Biomphalaria glabrata previously infected with L1. Adult worms were recovered from rodent mesenteric arteries. Protein extraction was performed after repeated freeze-thaw cycles followed by maceration of the nematodes in 40 mM Tris base. Proteolysis of gelatin was observed by zymography and found only in the larval stages. In L3, the gelatinolytic activity was effectively inhibited by orthophenanthroline, indicating the involvement of metalloproteases. The mechanistic class of the gelatinases from L1 could not be precisely determined using traditional class-specific inhibitors. Adult worm extracts were able to hydrolyze haemoglobin in solution, although no activity was observed by zymography. This haemoglobinolytic activity was ascribed to aspartic proteases following its effective inhibition by pepstatin, which also inhibited the haemoglobinolytic activity of L1 and L3 extracts. The characterization of protease expression throughout the A. costaricensis life cycle may reveal key factors influencing the process of parasitic infection and thus foster our understanding of the disease pathogenesis.

  10. Functional genomic characterization of neoblast-like stem cells in larval Schistosoma mansoni

    Science.gov (United States)

    Wang, Bo; Collins, James J; Newmark, Phillip A

    2013-01-01

    Schistosomes infect hundreds of millions of people in the developing world. Transmission of these parasites relies on a stem cell-driven, clonal expansion of larvae inside a molluscan intermediate host. How this novel asexual reproductive strategy relates to current models of stem cell maintenance and germline specification is unclear. Here, we demonstrate that this proliferative larval cell population (germinal cells) shares some molecular signatures with stem cells from diverse organisms, in particular neoblasts of planarians (free-living relatives of schistosomes). We identify two distinct germinal cell lineages that differ in their proliferation kinetics and expression of a nanos ortholog. We show that a vasa/PL10 homolog is required for proliferation and maintenance of both populations, whereas argonaute2 and a fibroblast growth factor receptor-encoding gene are required only for nanos-negative cells. Our results suggest that an ancient stem cell-based developmental program may have enabled the evolution of the complex life cycle of parasitic flatworms. DOI: http://dx.doi.org/10.7554/eLife.00768.001 PMID:23908765

  11. Developmental toxicity of two common corn pesticides to the endangered southern bell frog (Litoria raniformis)

    International Nuclear Information System (INIS)

    Choung, Catherine B.; Hyne, Ross V.; Mann, Reinier M.; Stevens, Mark M.; Hose, Grant C.

    2011-01-01

    To examine the link between corn agriculture and the observed decline of the endangered southern bell frog (SBF), the effects of two corn crop pesticides on larval growth and development were investigated. Tadpoles were exposed to terbufos sulfone (10 μg/L), a major breakdown product of the insecticide terbufos, and the herbicide atrazine (25 μg/L) individually and as a mixture until the completion of metamorphosis. Atrazine did not interact synergistically with terbufos sulfone or result in significant effects on growth and development alone, although there was some indication of accelerated metamorphosis in the pilot study. Terbufos sulfone alone and as a mixture (terbufos/atrazine) significantly slowed larval development and ultimately delayed metamorphosis. The observed developmental effects from an environmentally relevant concentration of terbufos sulfone indicates a risk posed by this persistent degradation product to the endangered SBF, which breeds and develops in the rice bays adjacent to corn fields treated with pesticides. - Highlights: → The effect of terbufos sulfone and atrazine on larval growth and development was investigated. → Terbufos sulfone alone significantly slowed development and delayed metamorphosis of tadpoles. → Atrazine had no observable effects alone nor did it interact synergistically with terbufos sulfone. → The developmental effects indicates a risk to endangered southern bell frogs in the irrigation area. → The results highlight the toxicological importance of some pesticide breakdown products. - A breakdown product of the insecticide terbufos retards development and delays metamorphosis of southern bell frog tadpoles.

  12. Developmental toxicity of two common corn pesticides to the endangered southern bell frog (Litoria raniformis)

    Energy Technology Data Exchange (ETDEWEB)

    Choung, Catherine B., E-mail: Catherine.Choung@mq.edu.au [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia); Hyne, Ross V. [Ecotoxicology and Environmental Contaminants Section, Office of Environment and Heritage, PO Box 29, Lidcombe, NSW 1825 (Australia); Mann, Reinier M. [Centre for Environmental Sustainability, University of Technology - Sydney, PO Box 123, Broadway, NSW 2007 (Australia); Stevens, Mark M. [EH Graham Centre for Agricultural Innovation (Industry and Investment NSW and Charles Sturt University), Yanco Agricultural Institute, Private Mail Bag, Yanco, NSW 2703 (Australia); Hose, Grant C. [Department of Biological Sciences, Macquarie University, Sydney, NSW 2109 (Australia)

    2011-10-15

    To examine the link between corn agriculture and the observed decline of the endangered southern bell frog (SBF), the effects of two corn crop pesticides on larval growth and development were investigated. Tadpoles were exposed to terbufos sulfone (10 {mu}g/L), a major breakdown product of the insecticide terbufos, and the herbicide atrazine (25 {mu}g/L) individually and as a mixture until the completion of metamorphosis. Atrazine did not interact synergistically with terbufos sulfone or result in significant effects on growth and development alone, although there was some indication of accelerated metamorphosis in the pilot study. Terbufos sulfone alone and as a mixture (terbufos/atrazine) significantly slowed larval development and ultimately delayed metamorphosis. The observed developmental effects from an environmentally relevant concentration of terbufos sulfone indicates a risk posed by this persistent degradation product to the endangered SBF, which breeds and develops in the rice bays adjacent to corn fields treated with pesticides. - Highlights: > The effect of terbufos sulfone and atrazine on larval growth and development was investigated. > Terbufos sulfone alone significantly slowed development and delayed metamorphosis of tadpoles. > Atrazine had no observable effects alone nor did it interact synergistically with terbufos sulfone. > The developmental effects indicates a risk to endangered southern bell frogs in the irrigation area. > The results highlight the toxicological importance of some pesticide breakdown products. - A breakdown product of the insecticide terbufos retards development and delays metamorphosis of southern bell frog tadpoles.

  13. Social coercion of larval development in an ant species.

    Science.gov (United States)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  14. Social coercion of larval development in an ant species

    Science.gov (United States)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  15. Rapid effects of marine reserves via larval dispersal.

    Directory of Open Access Journals (Sweden)

    Richard Cudney-Bueno

    Full Text Available Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs, with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

  16. Characterisation of Culex quinquefasciatus (Diptera: Culicidae larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Marta Grech

    2013-09-01

    Full Text Available The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase.

  17. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    Energy Technology Data Exchange (ETDEWEB)

    McKinley, Andrew C., E-mail: andrew.mckinley@hotmail.com [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia); Miskiewicz, Anthony [Environment and Recreation, Wollongong City Council, 41 Burelli Street, Wollongong, New South Wales 2500 (Australia); Taylor, Matthew D.; Johnston, Emma L. [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia)

    2011-06-15

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: > We examine contamination/habitat modification impacts on larval fish. > Larvae communities differ between modified/unmodified estuaries. > Larvae are more abundant/diverse in modified areas. > Trends are strongly related to sediment metals/seagrass cover. > Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

  18. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    International Nuclear Information System (INIS)

    McKinley, Andrew C.; Miskiewicz, Anthony; Taylor, Matthew D.; Johnston, Emma L.

    2011-01-01

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: → We examine contamination/habitat modification impacts on larval fish. → Larvae communities differ between modified/unmodified estuaries. → Larvae are more abundant/diverse in modified areas. → Trends are strongly related to sediment metals/seagrass cover. → Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

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

    Science.gov (United States)

    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. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  20. Efficiency of selection methods for increased ratio of pupal-larval to adult-larval weight gains in Tribolium.

    Science.gov (United States)

    Campo, J L; Cobos, P

    1994-01-12

    Four lines of Tribolium castaneum were selected in each of three replicates for increased ratio of (pupal-larval) to (adult-larval) weight gains, using selection for increased (pupal-larval) weight gain (PL), selection for decreased (adult-larval) weight gain (AL), direct selection for the ratio (R) and linear selection index of larval, pupal and adult weights (I), respectively, for four generations. Linear index was calculated with economic weights of m(2) -m(3) , m(3) -m(1) and m(1) -m(2) , respectively, with m(1) , m(2) and m(3) being the means for larval, pupal and adult weights. Selection to increase the ratio is considered to be a method to maximize the mean response in (adult-larval) weight while controlling the response in (pupal-adult) weight, and as a form of antagonistic selection to increase the weight gain during a given age period relative to the gain at another age period. Larval, pupal and adult weights were measured at 14, 21 and 28 days after adult emergence, respectively. The selected proportion was 20 % in all lines. The response observed for the ratio differed significantly among lines (p adulto-peso de larva en Tribolium Cuatro líneas de Tribolium castaneum fueron seleccionadas en cada una de tres repeticiones para incrementar el cociente (peso de pupa-peso de larva)/(peso de adulto-peso de larva); la línea PL fue seleccionada para aumentar la diferencia (peso de pupa-pesp de larva), la línea AL fue seleccionada para disminuir la diferencia (peso de adulto-peso de larva), fa línea R fue seleccionada directamente para el cociente, y la línea I fue seleccionada por medio de un índice lineal basado en los pesos de larva, pupa y adulto, durante cuatro generaciones. El índice lineal se calculó con pesos económicos de (m(2) -m(3) ), (m(3) -m(1) ), y (m(1) -m(2) ) respectivamentee, siendo m(1) , m(2) , y m(3) los valores medios para el peso de larva, pupa y adulto. La selección para aumentar el cociente indicado es un método para maximizar

  1. Reading in developmental prosopagnosia

    DEFF Research Database (Denmark)

    Starrfelt, Randi; Klargaard, Solja K; Petersen, Anders

    2018-01-01

    exposure durations (targeting the word superiority effect), and d) text reading. RESULTS: Participants with developmental prosopagnosia performed strikingly similar to controls across the four reading tasks. Formal analysis revealed a significant dissociation between word and face recognition......, that is, impaired reading in developmental prosopagnosia. METHOD: We tested 10 adults with developmental prosopagnosia and 20 matched controls. All participants completed the Cambridge Face Memory Test, the Cambridge Face Perception test and a Face recognition questionnaire used to quantify everyday face...... recognition experience. Reading was measured in four experimental tasks, testing different levels of letter, word, and text reading: (a) single word reading with words of varying length,(b) vocal response times in single letter and short word naming, (c) recognition of single letters and short words at brief...

  2. Developmental psychopathology in an era of molecular genetics and neuroimaging: A developmental neurogenetics approach.

    Science.gov (United States)

    Hyde, Luke W

    2015-05-01

    The emerging field of neurogenetics seeks to model the complex pathways from gene to brain to behavior. This field has focused on imaging genetics techniques that examine how variability in common genetic polymorphisms predict differences in brain structure and function. These studies are informed by other complimentary techniques (e.g., animal models and multimodal imaging) and have recently begun to incorporate the environment through examination of Imaging Gene × Environment interactions. Though neurogenetics has the potential to inform our understanding of the development of psychopathology, there has been little integration between principles of neurogenetics and developmental psychopathology. The paper describes a neurogenetics and Imaging Gene × Environment approach and how these approaches have been usefully applied to the study of psychopathology. Six tenets of developmental psychopathology (the structure of phenotypes, the importance of exploring mechanisms, the conditional nature of risk, the complexity of multilevel pathways, the role of development, and the importance of who is studied) are identified, and how these principles can further neurogenetics applications to understanding the development of psychopathology is discussed. A major issue of this piece is how neurogenetics and current imaging and molecular genetics approaches can be incorporated into developmental psychopathology perspectives with a goal of providing models for better understanding pathways from among genes, environments, the brain, and behavior.

  3. The Developmental Work

    DEFF Research Database (Denmark)

    Møller, Niels; Hvid, Helge

    2001-01-01

    AbstractIn the nineties, the concept of the developmental work (DW) has become a significant point of orientation for the actors on Danish labour market. The DW has moved the focus of the labour market from wages and working time towards work and production. For employees, the DW promises...... developmental possibilities, influence and responsibility, but also greater social responsibility for the firm. For firms, the DW promises increased competitiveness and better products. In this paper we present the concept of the DW as one which encourages the development of work, production and organisation...... of the firm and show that the DW is different from mainstream management concepts, as the DW...

  4. Post-Colonization Interval Estimates Using Multi-Species Calliphoridae Larval Masses and Spatially Distinct Temperature Data Sets: A Case Study

    Science.gov (United States)

    Weatherbee, Courtney R.; Pechal, Jennifer L.; Stamper, Trevor; Benbow, M. Eric

    2017-01-01

    Common forensic entomology practice has been to collect the largest Diptera larvae from a scene and use published developmental data, with temperature data from the nearest weather station, to estimate larval development time and post-colonization intervals (PCIs). To evaluate the accuracy of PCI estimates among Calliphoridae species and spatially distinct temperature sources, larval communities and ambient air temperature were collected at replicate swine carcasses (N = 6) throughout decomposition. Expected accumulated degree hours (ADH) associated with Cochliomyia macellaria and Phormia regina third instars (presence and length) were calculated using published developmental data sets. Actual ADH ranges were calculated using temperatures recorded from multiple sources at varying distances (0.90 m–7.61 km) from the study carcasses: individual temperature loggers at each carcass, a local weather station, and a regional weather station. Third instars greatly varied in length and abundance. The expected ADH range for each species successfully encompassed the average actual ADH for each temperature source, but overall under-represented the range. For both calliphorid species, weather station data were associated with more accurate PCI estimates than temperature loggers associated with each carcass. These results provide an important step towards improving entomological evidence collection and analysis techniques, and developing forensic error rates. PMID:28375172

  5. Post-Colonization Interval Estimates Using Multi-Species Calliphoridae Larval Masses and Spatially Distinct Temperature Data Sets: A Case Study

    Directory of Open Access Journals (Sweden)

    Courtney R. Weatherbee

    2017-04-01

    Full Text Available Common forensic entomology practice has been to collect the largest Diptera larvae from a scene and use published developmental data, with temperature data from the nearest weather station, to estimate larval development time and post-colonization intervals (PCIs. To evaluate the accuracy of PCI estimates among Calliphoridae species and spatially distinct temperature sources, larval communities and ambient air temperature were collected at replicate swine carcasses (N = 6 throughout decomposition. Expected accumulated degree hours (ADH associated with Cochliomyia macellaria and Phormia regina third instars (presence and length were calculated using published developmental data sets. Actual ADH ranges were calculated using temperatures recorded from multiple sources at varying distances (0.90 m–7.61 km from the study carcasses: individual temperature loggers at each carcass, a local weather station, and a regional weather station. Third instars greatly varied in length and abundance. The expected ADH range for each species successfully encompassed the average actual ADH for each temperature source, but overall under-represented the range. For both calliphorid species, weather station data were associated with more accurate PCI estimates than temperature loggers associated with each carcass. These results provide an important step towards improving entomological evidence collection and analysis techniques, and developing forensic error rates.

  6. Avian models in teratology and developmental toxicology.

    Science.gov (United States)

    Smith, Susan M; Flentke, George R; Garic, Ana

    2012-01-01

    The avian embryo is a long-standing model for developmental biology research. It also has proven utility for toxicology research both in ovo and in explant culture. Like mammals, avian embryos have an allantois and their developmental pathways are highly conserved with those of mammals, thus avian models have biomedical relevance. Fertile eggs are inexpensive and the embryo develops rapidly, allowing for high-throughput. The chick genome is sequenced and significant molecular resources are available for study, including the ability for genetic manipulation. The absence of a placenta permits the direct study of an agent's embryotoxic effects. Here, we present protocols for using avian embryos in toxicology research, including egg husbandry and hatch, toxicant delivery, and assessment of proliferation, apoptosis, and cardiac structure and function.

  7. Pathogen-induced Caenorhabditis elegans developmental plasticity has a hormetic effect on the resistance to biotic and abiotic stresses

    Directory of Open Access Journals (Sweden)

    Leroy Magali

    2012-09-01

    Full Text Available Abstract Background Phenotypic plasticity, i.e. the capacity to change the phenotype in response to changes in the environment without alteration of the genotype, is important for coping with unstable environments. In spite of the ample evidence that microorganisms are a major environmental component playing a significant role in eukaryotic organisms health and disease, there is not much information about the effect of microorganism-induced developmental phenotypic plasticity on adult animals’ stress resistance and longevity. Results We examined the consequences of development of Caenorhabditis elegans larvae fed with different bacterial strains on stress resistance and lifespan of adult nematodes. Bacterial strains used in this study were either pathogenic or innocuous to nematodes. Exposure to the pathogen during development did not affect larval survival. However, the development of nematodes on the pathogenic bacterial strains increased lifespan of adult nematodes exposed to the same or a different pathogen. A longer nematode lifespan, developed on pathogens and exposed to pathogens as adults, did not result from an enhanced capacity to kill bacteria, but is likely due to an increased tolerance to the damage inflicted by the pathogenic bacteria. We observed that adult nematodes developed on a pathogen induce higher level of expression of the hsp-16.2 gene and have higher resistance to heat shock than nematodes developed on an innocuous strain. Therefore, the increased resistance to pathogens could be, at least partially, due to the early induction of the heat shock response in nematodes developed on pathogens. The lifespan increase is controlled by the DBL-1 transforming growth factor beta-like, DAF-2/DAF-16 insulin-like, and p38 MAP kinase pathways. Therefore, the observed modulation of adult nematode lifespans by developmental exposure to a pathogen is likely a genetically controlled response. Conclusions Our study shows that development

  8. Developmental ecology of the American horseshoe crab Limulus polyphemus

    Directory of Open Access Journals (Sweden)

    Mark L. BOTTON, Richard A. TANKERSLEY, Robert E. LOVELAND

    2010-10-01

    Full Text Available During spawning events, horseshoe crab eggs are released from the female’s oviducts, and fertilized by one or more males. Eggs are shaped by the female into discrete clutches deposited in nests at depths of 10-20 cm on intertidal estuarine beaches. Distinguishing between fresh eggs and the early developmental stages is obfuscated by the large amount of dense, opaque yolk. The first unambiguous confirmation of development is the formation of the rudimentary prosomatic appendages at the “limb bud” stage. Several days thereafter, the outer chorion is shed and the developing embryo expands and undergoes a series of molts within the clear inner egg membrane. The trilobite (first instar stage thus attained may remain within the beach sediments for several more weeks, until hatching is facilitated by environmental factors such as hydration, agitation, and osmotic shock that accompany the infiltration of seawater into the nests. Trilobites exhibit endogenous circatidal swimming rhythms that are entrained by mechanical agitation, suggesting that peaks in larval swimming are timed to coincide with periods of high water and the inundation of the nests. Larval swimming is limited and does not appear to result in long-distance dispersal. The limited dispersal of the larvae has important implications for the population dynamics of relatively isolated populations. The rate of larval development is highly plastic and is influenced by temperature, salinity, dissolved oxygen, and the presence of pollutants. The broad environmental tolerances of horseshoe crab embryos and larvae are important in understanding their current geographic distribution and their evolutionary persistence [Current Zoology 56 (5: 550–562, 2010].

  9. Arguments from Developmental Order.

    Science.gov (United States)

    Stöckle-Schobel, Richard

    2016-01-01

    In this article, I investigate a special type of argument regarding the role of development in theorizing about psychological processes and cognitive capacities. Among the issues that developmental psychologists study, discovering the ontogenetic trajectory of mechanisms or capacities underpinning our cognitive functions ranks highly. The order in which functions are developed or capacities are acquired is a matter of debate between competing psychological theories, and also philosophical conceptions of the mind - getting the role and the significance of the different steps in this order right could be seen as an important virtue of such theories. Thus, a special kind of strategy in arguments between competing philosophical or psychological theories is using developmental order in arguing for or against a given psychological claim. In this article, I will introduce an analysis of arguments from developmental order, which come in two general types: arguments emphasizing the importance of the early cognitive processes and arguments emphasizing the late cognitive processes. I will discuss their role in one of the central tools for evaluating scientific theories, namely in making inferences to the best explanation. I will argue that appeal to developmental order is, by itself, an insufficient criterion for theory choice and has to be part of an argument based on other core explanatory or empirical virtues. I will end by proposing a more concerted study of philosophical issues concerning (cognitive) development, and I will present some topics that also pertain to a full-fledged 'philosophy of development.'

  10. Developmental Education Evaluation Model.

    Science.gov (United States)

    Perry-Miller, Mitzi; And Others

    A developmental education evaluation model designed to be used at a multi-unit urban community college is described. The purpose of the design was to determine the cost effectiveness/worth of programs in order to initiate self-improvement. A needs assessment was conducted by interviewing and taping the responses of students, faculty, staff, and…

  11. Arguments from Developmental Order

    Directory of Open Access Journals (Sweden)

    Richard eStöckle-Schobel

    2016-05-01

    Full Text Available In this article, I investigate a special type of argument regarding the role of development in theorising about psychological processes and cognitive capacities. Among the issues that developmental psychologists study, discovering the ontogenetic trajectory of mechanisms or capacities underpinning our cognitive functions ranks highly. The order in which functions are developed or capacities are acquired is a matter of debate between competing psychological theories, and also philosophical conceptions of the mind – getting the role and the significance of the different steps in this order right could be seen as an important virtue of such theories.Thus, a special kind of strategy in arguments between competing philosophical or psychological theories is using developmental order in arguing for or against a given psychological claim. In this article, I will introduce an analysis of arguments from developmental order, which come in two general types: arguments emphasising the importance of the early cognitive processes and arguments emphasising the late cognitive processes. I will discuss their role in one of the central tools for evaluating scientific theories, namely in making inferences to the best explanation. I will argue that appeal to developmental order is, by itself, an insufficient criterion for theory choice and has to be part of an argument based on other core explanatory or empirical virtues. I will end by proposing a more concerted study of philosophical issues concerning (cognitive development, and I will present some topics that also pertain to a full-fledged ‘philosophy of development’.

  12. Developmental paediatric anaesthetic pharmacology

    DEFF Research Database (Denmark)

    Hansen, Tom Giedsing

    2015-01-01

    Safe and effective drug therapy in neonates, infants and children require detailed knowledge about the ontogeny of drug disposition and action as well how these interact with genetics and co-morbidity of children. Recent advances in developmental pharmacology in children follow the increased...

  13. Applied Developmental Biology: Making Human Pancreatic Beta Cells for Diabetics.

    Science.gov (United States)

    Melton, Douglas A

    2016-01-01

    Understanding the genes and signaling pathways that determine the differentiation and fate of a cell is a central goal of developmental biology. Using that information to gain mastery over the fates of cells presents new approaches to cell transplantation and drug discovery for human diseases including diabetes. © 2016 Elsevier Inc. All rights reserved.

  14. Homeless Youth in the United States: Description and Developmental Issues.

    Science.gov (United States)

    Smollar, Jacqueline

    1999-01-01

    Reviews the history and causes of homeless children in the United States from early 19th century to the present. Explores four characteristics necessary for positive developmental pathways that are compromised for children who live on the street: sense of industry and competency, feeling connected to others and society, sense of control of one's…

  15. Diversity of developmental patterns in achelate lobsters-today and in the Mesozoic.

    Science.gov (United States)

    Haug, Joachim T; Audo, Denis; Charbonnier, Sylvain; Haug, Carolin

    2013-11-01

    Modern achelate lobsters, slipper and spiny lobsters, have a specific post-embryonic developmental pattern with the following phases: phyllosoma, nisto (slipper lobsters) or puerulus (spiny lobsters), juvenile and adult. The phyllosoma is a peculiar larva, which transforms through a metamorphic moult into another larval form, the nisto or puerulus which largely resembles the juvenile. Unlike the nisto and puerulus, the phyllosoma is characterised by numerous morphological differences to the adult, e.g. a thin head shield, elongate appendages, exopods on these appendages and a special claw. Our reinvestigation of the 85 million years old fossil "Eryoneicus sahelalmae" demonstrates that it represents an unusual type of achelatan lobster larva, characterised by a mixture of phyllosoma and post-phyllosoma characters. We ascribe it to its own genus: Polzicaris nov. gen. We study its significance by comparisons with other cases of Mesozoic fossil larvae also characterised by a mixture of characters. Accordingly, all these larvae are interpreted as ontogenetic intermediates between phyllosoma and post-phyllosoma morphology. Remarkably, most of the larvae show a unique mixture of retained larval and already developed post-larval features. Considering the different-and incompatible-mixture of characters of each of these larvae and their wide geographical and temporal distribution, we interpret all these larvae as belonging to distinct species. The particular character combinations in the different larvae make it currently difficult to reconstruct an evolutionary scenario with a stepwise character acquisition. Yet, it can be concluded that a larger diversity of larval forms and developmental patterns occurred in Mesozoic than in modern faunas.

  16. Reduce, reuse, and recycle: developmental evolution of trait diversification.

    Science.gov (United States)

    Preston, Jill C; Hileman, Lena C; Cubas, Pilar

    2011-03-01

    A major focus of evolutionary developmental (evo-devo) studies is to determine the genetic basis of variation in organismal form and function, both of which are fundamental to biological diversification. Pioneering work on metazoan and flowering plant systems has revealed conserved sets of genes that underlie the bauplan of organisms derived from a common ancestor. However, the extent to which variation in the developmental genetic toolkit mirrors variation at the phenotypic level is an active area of research. Here we explore evidence from the angiosperm evo-devo literature supporting the frugal use of genes and genetic pathways in the evolution of developmental patterning. In particular, these examples highlight the importance of genetic pleiotropy in different developmental modules, thus reducing the number of genes required in growth and development, and the reuse of particular genes in the parallel evolution of ecologically important traits.

  17. Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

    Directory of Open Access Journals (Sweden)

    Megan J Donahue

    Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

  18. Redescription of the early larval stages of the pandalid shrimp Chlorotocus crassicornis (Decapoda: Caridea: Pandalidae).

    Science.gov (United States)

    Landeira, Jose M; Jiang, Guo-Chen; Chan, Tin-Yam; Shih, Tung-Wei; Gozález-Gordillo, J Ignacio

    2015-09-07

    The first four larval stages of the pandalid shrimp Chlorotocus crassicornis (A. Costa, 1871) are described and illustrated from laboratory-reared material obtained from ovigerous females collected in the southwestern Spain and south Taiwan. The second to fourth larval stages of this species are reported for the first time to science. Detailed examination of the first larval stages reveals that previous description misidentified some key larval characters which have prevented its identification in plankton samples. It is found that the zoeal morphology of Chlorotocus is not very different from other pandalid larvae, and in fact closely resembles Plesionika and Heterocarpus.

  19. Effects of juvenile hormone (JH) analog insecticides on larval development and JH esterase activity in two spodopterans.

    Science.gov (United States)

    El-Sheikh, El-Sayed A; Kamita, Shizuo G; Hammock, Bruce D

    2016-03-01

    Juvenile hormone analog (JHA) insecticides are biological and structural mimics of JH, a key insect developmental hormone. Toxic and anti-developmental effects of the JHA insecticides methoprene, fenoxycarb, and pyriproxyfen were investigated on the larval and pupal stages of Spodoptera littoralis and Spodoptera frugiperda. Bioassays showed that fenoxycarb has the highest toxicity and fastest speed of kill in 2nd instar S. littoralis. All three JHAs affected the development of 6th instar (i.e., final instar) and pupal S. frugiperda. JH esterase (JHE) is a critical enzyme that helps to regulate JH levels during insect development. JHE activity in the last instar S. littoralis and S. frugiperda was 11 and 23 nmol min(-1) ml(-1) hemolymph, respectively. Methoprene and pyriproxyfen showed poor inhibition of JHE activity from these insects, whereas fenoxycarb showed stronger inhibition. The inhibitory activity of fenoxycarb, however, was more than 1000-fold lower than that of OTFP, a highly potent inhibitor of JHEs. Surprisingly, topical application of methoprene, fenoxycarb or pyriproxyfen on 6th instars of S. littoralis and S. frugiperda prevented the dramatic reduction in JHE activity that was found in control insects. Our findings suggest that JHAs may function as JH agonists that play a disruptive role or a hormonal replacement role in S. littoralis and S. frugiperda. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Do effects of mercury in larval amphibians persist after metamorphosis?

    Science.gov (United States)

    Todd, Brian D; Willson, John D; Bergeron, Christine M; Hopkins, William A

    2012-01-01

    Despite widespread concern about the role of environmental contaminants in global amphibian declines, and evidence that post-metamorphic life stages contribute disproportionately to amphibian population dynamics, most studies in amphibian ecotoxicology focus on larval life stages. Studies that focus solely on early life stages may miss important effects of contaminant exposure, such as latent effects that manifest some time after previous exposure. Moreover, it is often assumed that effects observed in amphibian larvae will persist to affect survival or reproduction later in life. We used terrestrial enclosures to determine whether exposure to mercury (Hg) through maternal transfer and/or larval diet had any adverse effects in post-metamorphic American toads (Bufo americanus). We found a 5% difference in size at metamorphosis that was attributed to maternal Hg exposure persisted for 1 year in the terrestrial environment, resulting in a 7% difference at the conclusion of the study. Although patterns of survival differed among treatments through time, we found no overall difference in survival after 1 year. We also found no evidence of emergent latent effects in the terrestrial toads that could be attributed to earlier exposure. Our results indicate that adverse effects of maternal Hg exposure that were observed in larval amphibians may persist to affect later terrestrial life stages but that no novel adverse effects developed when animals were raised in a semi-natural environment. Moreover, we found no evidence of persistent effects of dietary Hg exposure in larvae, highlighting a need for greater focus on maternal effects in amphibian ecotoxicology. Finally, we suggest an increase in the use of longitudinal studies to better understand contaminant impacts to amphibian populations via effects in both aquatic and terrestrial life stages.

  1. Ocean acidification alters temperature and salinity preferences in larval fish.

    Science.gov (United States)

    Pistevos, Jennifer C A; Nagelkerken, Ivan; Rossi, Tullio; Connell, Sean D

    2017-02-01

    Ocean acidification alters the way in which animals perceive and respond to their world by affecting a variety of senses such as audition, olfaction, vision and pH sensing. Marine species rely on other senses as well, but we know little of how these might be affected by ocean acidification. We tested whether ocean acidification can alter the preference for physicochemical cues used for dispersal between ocean and estuarine environments. We experimentally assessed the behavioural response of a larval fish (Lates calcarifer) to elevated temperature and reduced salinity, including estuarine water of multiple cues for detecting settlement habitat. Larval fish raised under elevated CO 2 concentrations were attracted by warmer water, but temperature had no effect on fish raised in contemporary CO 2 concentrations. In contrast, contemporary larvae were deterred by lower salinity water, where CO 2 -treated fish showed no such response. Natural estuarine water-of higher temperature, lower salinity, and containing estuarine olfactory cues-was only preferred by fish treated under forecasted high CO 2 conditions. We show for the first time that attraction by larval fish towards physicochemical cues can be altered by ocean acidification. Such alterations to perception and evaluation of environmental cues during the critical process of dispersal can potentially have implications for ensuing recruitment and population replenishment. Our study not only shows that freshwater species that spend part of their life cycle in the ocean might also be affected by ocean acidification, but that behavioural responses towards key physicochemical cues can also be negated through elevated CO 2 from human emissions.

  2. Parasites of larval black flies (Diptera: Simuliidae in Thailand

    Directory of Open Access Journals (Sweden)

    Sanae Jitklang

    2012-12-01

    Full Text Available Parasites of larval black flies are reported for the first time from Thailand, including mermithid nematodes(Mermithidae, microsporidian fungi (Zygomycota, and the fungus Coelomycidium simulii Debaisieux (Blastocladiomycetes.The following nine species of black flies were infected with one or more parasites: Simulium asakoae, S. chamlongi,S. chiangmaiense, S. fenestratum, S. feuerborni, S. nakhonense, S. nodosum, S. quinquestriatum, and S. tani. The prevalenceof patent infections per host species per season was 0.1–7.1% for mermithids, 0.1–6.0% for microsporidia, and 0.1–3.0% forC. simulii.

  3. NIDCAP and developmental care

    Directory of Open Access Journals (Sweden)

    Dominique Haumont

    2014-06-01

    Full Text Available Perinatal mortality in very low birth weight infants has dramatically decreased during the last decades. However, 15-25% of these infants will show neurodevelopmental impairment later on. The aim of implementing early developmental care (EDC, emerged as a new field in neonatology, is to create an intervention program designed to provide support for optimal neurobehavioral development during this highly vulnerable period of brain growth. The theoretical framework, which underlies the approach, is supported by research in different scientific fields, including neuroscience, psychology, medicine and nursing. EDC utilizes a range of medical and nursing interventions that aim to decrease the stress of preterm neonates in neonatal intensive care units (NICUs. The Neonatal Individualized Developmental Care Assessment Program (NIDCAP is an integrated and holistic form of family-centered developmental care. Changing the traditional NICU towards an EDC-NICU includes training nursing and medical staff, investing in their quality and most importantly keeping parents in proximity to the infants. The new challenge of modern neonatology is to restore the mother-infant dyad applying “couplet care” starting at birth until discharge. Most of the European NICUs apply some elements of EDC, but it is more consistent in northern Europe. The development of NIDCAP training centers in Europe demonstrates the evolution of care. It is likely that future research and intervention programs will optimize our practices. Developmental care could prove to be an important recent step in improving outcome in extremely preterm neonates. Proceedings of the 10th International Workshop on Neonatology · Cagliari (Italy · October 22nd-25th, 2014 · The last ten years, the next ten years in Neonatology Guest Editors: Vassilios Fanos, Michele Mussap, Gavino Faa, Apostolos Papageorgiou

  4. Evolutionary and developmental modules.

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yuri P; d'Avella, Andrea; Zelik, Karl E; Zago, Myrka

    2013-01-01

    The identification of biological modules at the systems level often follows top-down decomposition of a task goal, or bottom-up decomposition of multidimensional data arrays into basic elements or patterns representing shared features. These approaches traditionally have been applied to mature, fully developed systems. Here we review some results from two other perspectives on modularity, namely the developmental and evolutionary perspective. There is growing evidence that modular units of development were highly preserved and recombined during evolution. We first consider a few examples of modules well identifiable from morphology. Next we consider the more difficult issue of identifying functional developmental modules. We dwell especially on modular control of locomotion to argue that the building blocks used to construct different locomotor behaviors are similar across several animal species, presumably related to ancestral neural networks of command. A recurrent theme from comparative studies is that the developmental addition of new premotor modules underlies the postnatal acquisition and refinement of several different motor behaviors in vertebrates.

  5. Lipid Uptake, Metabolism, and Transport in the Larval Zebrafish

    Directory of Open Access Journals (Sweden)

    Vanessa H. Quinlivan

    2017-11-01

    Full Text Available The developing zebrafish is a well-established model system for studies of energy metabolism, and is amenable to genetic, physiological, and biochemical approaches. For the first 5 days of life, nutrients are absorbed from its endogenous maternally deposited yolk. At 5 days post-fertilization, the yolk is exhausted and the larva has a functional digestive system including intestine, liver, gallbladder, pancreas, and intestinal microbiota. The transparency of the larval zebrafish, and the genetic and physiological similarity of its digestive system to that of mammals make it a promising system in which to address questions of energy homeostasis relevant to human health. For example, apolipoprotein expression and function is similar in zebrafish and mammals, and transgenic animals may be used to examine both the transport of lipid from yolk to body in the embryo, and the trafficking of dietary lipids in the larva. Additionally, despite the identification of many fatty acid and lipid transport proteins expressed by vertebrates, the cell biological processes that mediate the transport of dietary lipids from the intestinal lumen to the interior of enterocytes remain to be elucidated. Genetic tractability and amenability to live imaging and a range of biochemical methods make the larval zebrafish an ideal model in which to address open questions in the field of lipid transport, energy homeostasis, and nutrient metabolism.

  6. Larval fish dispersal in a coral-reef seascape

    KAUST Repository

    Almany, Glenn R.

    2017-05-23

    Larval dispersal is a critical yet enigmatic process in the persistence and productivity of marine metapopulations. Empirical data on larval dispersal remain scarce, hindering the use of spatial management tools in efforts to sustain ocean biodiversity and fisheries. Here we document dispersal among subpopulations of clownfish (Amphiprion percula) and butterflyfish (Chaetodon vagabundus) from eight sites across a large seascape (10,000 km2) in Papua New Guinea across 2 years. Dispersal of clownfish was consistent between years, with mean observed dispersal distances of 15 km and 10 km in 2009 and 2011, respectively. A Laplacian statistical distribution (the dispersal kernel) predicted a mean dispersal distance of 13–19 km, with 90% of settlement occurring within 31–43 km. Mean dispersal distances were considerably greater (43–64 km) for butterflyfish, with kernels declining only gradually from spawning locations. We demonstrate that dispersal can be measured on spatial scales sufficient to inform the design of and test the performance of marine reserve networks.

  7. The influence of substrate material on ascidian larval settlement.

    Science.gov (United States)

    Chase, Anna L; Dijkstra, Jennifer A; Harris, Larry G

    2016-05-15

    Submerged man-made structures present novel habitat for marine organisms and often host communities that differ from those on natural substrates. Although many factors are known to contribute to these differences, few studies have directly examined the influence of substrate material on organism settlement. We quantified larval substrate preferences of two species of ascidians, Ciona intestinalis (cryptogenic, formerly C. intestinalis type B) and Botrylloides violaceus (non-native), on commonly occurring natural (granite) and man-made (concrete, high-density polyethylene, PVC) marine materials in laboratory trials. Larvae exhibited species-specific settlement preferences, but generally settled more often than expected by chance on concrete and HDPE. Variation in settlement between materials may reflect preferences for rougher substrates, or may result from the influence of leached chemicals on ascidian settlement. These findings indicate that an experimental plate material can influence larval behavior and may help us understand how substrate features may contribute to differences in settlement in the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Larval fish dispersal in a coral-reef seascape

    KAUST Repository

    Almany, Glenn R.; Planes, Serge; Thorrold, Simon R.; Berumen, Michael L.; Bode, Michael; Saenz Agudelo, Pablo; Bonin, Mary C.; Frisch, Ashley J.; Harrison, Hugo B.; Messmer, Vanessa; Nanninga, Gerrit B.; Priest, Mark; Srinivasan, Maya; Sinclair-Taylor, Tane; Williamson, David H.; Jones, Geoffrey P.

    2017-01-01

    Larval dispersal is a critical yet enigmatic process in the persistence and productivity of marine metapopulations. Empirical data on larval dispersal remain scarce, hindering the use of spatial management tools in efforts to sustain ocean biodiversity and fisheries. Here we document dispersal among subpopulations of clownfish (Amphiprion percula) and butterflyfish (Chaetodon vagabundus) from eight sites across a large seascape (10,000 km2) in Papua New Guinea across 2 years. Dispersal of clownfish was consistent between years, with mean observed dispersal distances of 15 km and 10 km in 2009 and 2011, respectively. A Laplacian statistical distribution (the dispersal kernel) predicted a mean dispersal distance of 13–19 km, with 90% of settlement occurring within 31–43 km. Mean dispersal distances were considerably greater (43–64 km) for butterflyfish, with kernels declining only gradually from spawning locations. We demonstrate that dispersal can be measured on spatial scales sufficient to inform the design of and test the performance of marine reserve networks.

  9. Mosquito population regulation and larval source management in heterogeneous environments.

    Directory of Open Access Journals (Sweden)

    David L Smith

    Full Text Available An important question for mosquito population dynamics, mosquito-borne pathogen transmission and vector control is how mosquito populations are regulated. Here we develop simple models with heterogeneity in egg laying patterns and in the responses of larval populations to crowding in aquatic habitats. We use the models to evaluate how such heterogeneity affects mosquito population regulation and the effects of larval source management (LSM. We revisit the notion of a carrying capacity and show how heterogeneity changes our understanding of density dependence and the outcome of LSM. Crowding in and productivity of aquatic habitats is highly uneven unless egg-laying distributions are fine-tuned to match the distribution of habitats' carrying capacities. LSM reduces mosquito population density linearly with coverage if adult mosquitoes avoid laying eggs in treated habitats, but quadratically if eggs are laid in treated habitats and the effort is therefore wasted (i.e., treating 50% of habitat reduces mosquito density by approximately 75%. Unsurprisingly, targeting (i.e. treating a subset of the most productive pools gives much larger reductions for similar coverage, but with poor targeting, increasing coverage could increase adult mosquito population densities if eggs are laid in higher capacity habitats. Our analysis suggests that, in some contexts, LSM models that accounts for heterogeneity in production of adult mosquitoes provide theoretical support for pursuing mosquito-borne disease prevention through strategic and repeated application of modern larvicides.

  10. Effect of propolis extract on angelfish larval performance and transport

    Directory of Open Access Journals (Sweden)

    Douglas da Cruz Mattos

    2017-06-01

    Full Text Available This study aimed to evaluate the influence propolis extract inclusion to the feed mixture for juvenile angelfish (Pterophyllum scalare on larval performance and transport. Levels of propolis extract inclusion consisted of 0, 300, 600, 900, and 1200 mg.kg-1 of feed. After 14 days of hatching, unmetamorphosed larvae with a total length of 18.4 mm and 0.11 g initial weight were used. Six-hundred larvae were divided into 20 experimental units, totalizing 30 larvae each. Experimental units consisted of polythene containers with independent water input and output and a level controller. Each unit was controlled for maintenance of 40 L water within a recirculation system. After offering feed containing propolis extract, five fish from each experimental unit were packed in bags for transportation only with atmospheric air, without pure oxygen addition. The bags were filled with 300 mL water on a 2:1 basis of air and water respectively. The total transport time was considered until the death of the third fish in package. At the end of the experiment, data underwent statistical analysis through Statistical Analysis System (SAS, 2001. Results showed there was no significant difference (P < 0.05 neither for any of the studied zootechnical variables (standard length, total length, height, and weight nor for the transport of juveniles. In conclusion, propolis extract addition to angelfish feed was ineffective for larval performance and for transportation of juveniles, at the levels tested here.

  11. Small nonnative fishes as predators of larval razorback suckers

    Science.gov (United States)

    Carpenter, J.; Mueller, G.A.

    2008-01-01

    The razorback sucker (Xyrauchen texanus), an endangered big-river fish of the Colorado River basin, has demonstrated no sustainable recruitment in 4 decades, despite presence of spawning adults and larvae. Lack of adequate recruitment has been attributed to several factors, including predation by nonnative fishes. Substantial funding and effort has been expended on mechanically removing nonnative game fishes, typically targeting large predators. As a result, abundance of larger predators has declined, but the abundance of small nonnative fishes has increased in some areas. We conducted laboratory experiments to determine if small nonnative fishes would consume larval razorback suckers. We tested adults of three small species (threadfin shad, Dorosoma petenense; red shiner, Cyprinella lutrensis; fathead minnow, Pimephales promelas) and juveniles of six larger species (common carp, Cyprinus carpio; yellow bullhead, Ameiurus natalis; channel catfish, Ictalurus punctatus; rainbow trout, Oncorhynchus mykiss; green sunfish, Lepomis cyanellus; bluegill, L. macrochirus). These nonnative fishes span a broad ecological range and are abundant within the historical range of the razorback sucker. All nine species fed on larval razorback suckers (total length, 9-16 mm). Our results suggest that predation by small nonnative fishes could be responsible for limiting recovery of this endangered species.

  12. Numerical simulations of barnacle larval dispersion coupled with field observations on larval abundance, settlement and recruitment in a tropical monsoon influenced coastal marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Samiksha S.V.; George, G.; Aboobacker V.M.; Vethamony, P.; Anil, A.C.

    Observations were carried out to monitor the larval abundance, settlement and recruitment of barnacles on a regular basis for a period of two years. The results were then compared with the numerical modelling studies carried out along the west coast...

  13. EVALUATING THE EFFECTS OF FLY ASH EXPOSURE ON FISH EARLY LIFE STAGES: FATHEAD MINNOW EMBRYO-LARVAL TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Greeley Jr, Mark Stephen [ORNL; Elmore, Logan R [ORNL; McCracken, Kitty [ORNL

    2012-05-01

    current technical manuscript); (3) additional laboratory experimentation focused on the potential effects of long-term exposures to fly ash on fish survival and reproductive competence; and (4) a combined field and laboratory study examining the in vitro developmental success of embryos and larvae obtained from fish exposed in vivo for over two years to fly ash in the Emory and Clinch Rivers. These fish reproduction and early life-stage studies are being conducted in conjunction with a broader biological monitoring program administered by TVA that includes a field study of the condition of larval fish in the Emory and Clinch Rivers along with assessments of water quality, sediment composition, ecotoxicological studies, terrestrial wildlife studies, and human and ecological risk assessment. Information and data generated from these studies will provide direct input into risk assessment efforts and will also complement and help support other phases of the overall biomonitoring program. Fish eggs, in general, are known to be capable of concentrating heavy metals and other environmental contaminants from water-borne exposures during embryonic development (Jezierska and others 2009), and fathead minnow embryos in particular have been shown to concentrate methylmercury (Devlin 2006) as well as other chemical toxicants. This technical report focuses on the responses of fathead minnow embryos to simple contact exposures to fly ash in laboratory toxicity tests adapted from a standard fathead minnow (Pimephales promelas) 7-d embryo-larval survival and teratogenicity test (method 1001.0 in EPA 2002) with mortality, hatching success, and the incidences of developmental abnormalities as measured endpoints.

  14. Larval connectivity studies in the Western Iberian Peninsula

    Science.gov (United States)

    Dubert, Jesus; Nolasco, Rita; Queiroga, Henrique

    2010-05-01

    The study of the connectivity between populations is one of the 'hot' applications of numerical models of the ocean circulation. An IBM (Individual Based model) was developed, using Carcinus manenas larvae crab as a model. A set of particles was used as a representation of larvae, in order to study their larval life cycle, including the larval growth, larval mortality (both depending on temperature and salinity), larval dispersal by currents, diel vertical migration, and larval recruitment. The life cycle of every larvae in the ocean, was modeled from zoeae 1 stage to megalopae stage, during typical periods of 30-50 days. Larvae were initialized in 14 estuarine systems of the Atlantic Western Iberian Peninsula, from January to July. In every period, a number of 225 larvae are initialized in everyone of the 14 considered estuaries, with fortynighly periodicity. The larvae evolves during the (variable, depending mainly on temperature) period of growth in the ocean, and when a larvae reach the age for recruit, if it is located in the neighborhood of the considered estuarine systems, the larvae is accounted as a recruited larvae in that place. With this methodology, a connectivity matrix can be computed, acconting for the 225 larvae emitted in every estuary, the number of larvae that reaches the every place. The connectivity matrix depends strongly on the current regime along the Atlantic coast of Iberian Peninsula, and has been calculated for the present circulation, for the period 2001 to 2009, for runs with realistic forcing with NCEP2 and Quikscat (for winds) forcing. The connectivity matrix, have also been calculated for climatological runs. For the present climatological conditions, it is observed the prevalence of southward transport for the period January-July, because the prevalence of Northerly winds along the west coast of IP in the COADS present time climatology. Strong dispersal is observed at the Northern estuaries, during winter with strong loss of

  15. Comparative genomic analysis of Drosophila melanogaster and vector mosquito developmental genes.

    Directory of Open Access Journals (Sweden)

    Susanta K Behura

    Full Text Available Genome sequencing projects have presented the opportunity for analysis of developmental genes in three vector mosquito species: Aedes aegypti, Culex quinquefasciatus, and Anopheles gambiae. A comparative genomic analysis of developmental genes in Drosophila melanogaster and these three important vectors of human disease was performed in this investigation. While the study was comprehensive, special emphasis centered on genes that 1 are components of developmental signaling pathways, 2 regulate fundamental developmental processes, 3 are critical for the development of tissues of vector importance, 4 function in developmental processes known to have diverged within insects, and 5 encode microRNAs (miRNAs that regulate developmental transcripts in Drosophila. While most fruit fly developmental genes are conserved in the three vector mosquito species, several genes known to be critical for Drosophila development were not identified in one or more mosquito genomes. In other cases, mosquito lineage-specific gene gains with respect to D. melanogaster were noted. Sequence analyses also revealed that numerous repetitive sequences are a common structural feature of Drosophila and mosquito developmental genes. Finally, analysis of predicted miRNA binding sites in fruit fly and mosquito developmental genes suggests that the repertoire of developmental genes targeted by miRNAs is species-specific. The results of this study provide insight into the evolution of developmental genes and processes in dipterans and other arthropods, serve as a resource for those pursuing analysis of mosquito development, and will promote the design and refinement of functional analysis experiments.

  16. Genetic Basis for Developmental Homeostasis of Germline Stem Cell Niche Number: A Network of Tramtrack-Group Nuclear BTB Factors

    Science.gov (United States)

    Chalvet, Fabienne; Netter, Sophie; Dos Santos, Nicolas; Poisot, Emilie; Paces-Fessy, Mélanie; Cumenal, Delphine; Peronnet, Frédérique; Pret, Anne-Marie; Théodore, Laurent

    2012-01-01

    The potential to produce new cells during adult life depends on the number of stem cell niches and the capacity of stem cells to divide, and is therefore under the control of programs ensuring developmental homeostasis. However, it remains generally unknown how the number of stem cell niches is controlled. In the insect ovary, each germline stem cell (GSC) niche is embedded in a functional unit called an ovariole. The number of ovarioles, and thus the number of GSC niches, varies widely among species. In Drosophila, morphogenesis of ovarioles starts in larvae with the formation of terminal filaments (TFs), each made of 8–10 cells that pile up and sort in stacks. TFs constitute organizers of individual germline stem cell niches during larval and early pupal development. In the Drosophila melanogaster subgroup, the number of ovarioles varies interspecifically from 8 to 20. Here we show that pipsqueak, Trithorax-like, batman and the bric-à-brac (bab) locus, all encoding nuclear BTB/POZ factors of the Tramtrack Group, are involved in limiting the number of ovarioles in D. melanogaster. At least two different processes are differentially perturbed by reducing the function of these genes. We found that when the bab dose is reduced, sorting of TF cells into TFs was affected such that each TF contains fewer cells and more TFs are formed. In contrast, psq mutants exhibited a greater number of TF cells per ovary, with a normal number of cells per TF, thereby leading to formation of more TFs per ovary than in the wild type. Our results indicate that two parallel genetic pathways under the control of a network of nuclear BTB factors are combined in order to negatively control the number of germline stem cell niches. PMID:23185495

  17. Penaeid prawns in the St Lucia Lake System: Post-larval recruitment ...

    African Journals Online (AJOL)

    Penaeid prawns in the St Lucia Lake System: Post-larval recruitment and the bait fishery. ... Recruitment of post-larval penaeid prawns and the bait prawn fishery in the St Lucia Lake System were monitored for ... AJOL African Journals Online.

  18. Batch fertility and larval parameters of the jaguar cichlid (Cichlasoma managuense spawned in the laboratory (ESP

    Directory of Open Access Journals (Sweden)

    Jorge Günther Nonell

    2016-03-01

    Full Text Available Batch fertility and larval parameters of 32 spawns of the jaguar guapote (Cichlasoma managuense in the laboratory were analyzed. Batch fertility was positively correlated with the female weight with spawns between about 3000 to 6000 larvae for females between 100 and 500 g wet weight. No significant correlation was found between larval parameters (fresh weight and % dry weight and female weight.

  19. Toxicity of organophosphorus pesticide sumithion on larval stages of stinging catfish Heteropneustes fossilis

    NARCIS (Netherlands)

    Shahjahan, M.; Kabir, M.F.; Sumon, Kizar Ahmed; Bhowmik, Lipi Rani; Rashid, Harunur

    2017-01-01

    Sumithion is widely used to control brittle in paddy fields and tiger bug in fish larval rearing ponds. The objective of this study was to elucidate the toxic effects of sumithion on larval stages of stinging catfish Heteropneustes fossilis. Larvae were exposed to two concentrations (150 and 250

  20. Building clinical networks: a developmental evaluation framework.

    Science.gov (United States)

    Carswell, Peter; Manning, Benjamin; Long, Janet; Braithwaite, Jeffrey

    2014-05-01

    Clinical networks have been designed as a cross-organisational mechanism to plan and deliver health services. With recent concerns about the effectiveness of these structures, it is timely to consider an evidence-informed approach for how they can be developed and evaluated. To document an evaluation framework for clinical networks by drawing on the network evaluation literature and a 5-year study of clinical networks. We searched literature in three domains: network evaluation, factors that aid or inhibit network development, and on robust methods to measure network characteristics. This material was used to build a framework required for effective developmental evaluation. The framework's architecture identifies three stages of clinical network development; partner selection, network design and network management. Within each stage is evidence about factors that act as facilitators and barriers to network growth. These factors can be used to measure progress via appropriate methods and tools. The framework can provide for network growth and support informed decisions about progress. For the first time in one place a framework incorporating rigorous methods and tools can identify factors known to affect the development of clinical networks. The target user group is internal stakeholders who need to conduct developmental evaluation to inform key decisions along their network's developmental pathway.

  1. Effects of arginine vasotocin and mesotocin on the activation and development of amiloride-blockable short-circuit current across larval, adult, and cultured larval bullfrog skins.

    Science.gov (United States)

    Takada, Makoto; Fujimaki-Aoba, Kayo; Hokari, Shigeru

    2010-03-01

    Amphibian skin has osmoregulatory functions, with Na(+) crossing from outside to inside. Na(+) transport can be measured as the short-circuit current (SCC). We investigated the short-term and long-term effects of arginine vasotocin (AVT) and mesotocin (MT) (which modulate Na(+) transport) on the activation and development of an amiloride-blockable SCC (adult-type feature) in larval, adult, and corticoid-cultured larval bullfrog skins. We found: (1) AVT-receptor (AVT-R) and MT-receptor (MT-R) mRNAs could be detected in both larval and adult skins, (2) in the short term (within 60 min), the larval SCC (amiloride-stimulated SCC) was increased by AVT, forskolin, and MT, suggesting that AVT and MT did not activate the inactive ENaC (epithelial sodium channel) protein thought to be expressed in larval skin, (3) in the short term (within 90 min), AVT, forskolin, and MT stimulated the adult SCC (amiloride-blockable SCC), (4) AVT and MT increased both the larval and adult SCC via receptors insensitive to OPC-21268 (an antagonist of the V(1)-type receptor), OPC-31260 (an antagonist of the V(2)-type receptor), and ([d(CH(2))(5),Tyr(Me)(2),Thr(4),Orn(8),des-Gly-NH (2) (9) ]VT) (an antagonist of the oxytocin receptor), (5) culturing EDTA-treated larval skin with corticoids supplemented with AVT (1 microM) or MT (1 microM) for 2 weeks (long-term effects of AVT and MT) did not alter the corticoid-induced development of an amiloride-blockable SCC (adult-type feature). AVT and MT thus have the potential to stimulate SCC though channels that are already expressed, but they may not influence the development of the amiloride-blockable SCC (an adult-type feature) in larval skin.

  2. Applying Evolutionary Genetics to Developmental Toxicology and Risk Assessment

    Science.gov (United States)

    Leung, Maxwell C. K.; Procter, Andrew C.; Goldstone, Jared V.; Foox, Jonathan; DeSalle, Robert; Mattingly, Carolyn J.; Siddall, Mark E.; Timme-Laragy, Alicia R.

    2018-01-01

    Evolutionary thinking continues to challenge our views on health and disease. Yet, there is a communication gap between evolutionary biologists and toxicologists in recognizing the connections among developmental pathways, high-throughput screening, and birth defects in humans. To increase our capability in identifying potential developmental toxicants in humans, we propose to apply evolutionary genetics to improve the experimental design and data interpretation with various in vitro and whole-organism models. We review five molecular systems of stress response and update 18 consensual cell-cell signaling pathways that are the hallmark for early development, organogenesis, and differentiation; and revisit the principles of teratology in light of recent advances in high-throughput screening, big data techniques, and systems toxicology. Multiscale systems modeling plays an integral role in the evolutionary approach to cross-species extrapolation. Phylogenetic analysis and comparative bioinformatics are both valuable tools in identifying and validating the molecular initiating events that account for adverse developmental outcomes in humans. The discordance of susceptibility between test species and humans (ontogeny) reflects their differences in evolutionary history (phylogeny). This synthesis not only can lead to novel applications in developmental toxicity and risk assessment, but also can pave the way for applying an evo-devo perspective to the study of developmental origins of health and disease. PMID:28267574

  3. Characterization of 14-3-3 isoforms expressed in the Echinococcus granulosus pathogenic larval stage.

    Science.gov (United States)

    Teichmann, Aline; Vargas, Daiani M; Monteiro, Karina M; Meneghetti, Bruna V; Dutra, Cristine S; Paredes, Rodolfo; Galanti, Norbel; Zaha, Arnaldo; Ferreira, Henrique B

    2015-04-03

    The 14-3-3 protein family of eukaryotic regulators was studied in Echinococcus granulosus, the causative agent of cystic hydatid disease. These proteins mediate important cellular processes in eukaryotes and are expected to play important roles in parasite biology. Six isoforms of E. granulosus 14-3-3 genes and proteins (Eg14-3-3.1-6) were analyzed, and their phylogenetic relationships were established with bona fide 14-3-3 orthologous proteins from eukaryotic species. Eg14-3-3 isoforms with previous evidence of expression (Eg14-3-3.1-4) in E. granulosus pathogenic larval stage (metacestode) were cloned, and recombinant proteins were used for functional studies. These protein isoforms were detected in different components of E. granulosus metacestode, including interface components with the host. The roles that are played by Eg14-3-3 proteins in parasite biology were inferred from the repertoires of interacting proteins with each isoform, as assessed by gel overlay, cross-linking, and affinity chromatography assays. A total of 95 Eg14-3-3 protein ligands were identified by mass spectrometry. Eg14-3-3 isoforms have shared partners (44 proteins), indicating some overlapping functions; however, they also bind exclusive partners (51 proteins), suggesting Eg14-3-3 functional specialization. These ligand repertoires indicate the involvement of Eg14-3-3 proteins in multiple biochemical pathways in the E. granulosus metacestode and note some degree of isoform specialization.

  4. Azadirachtin Affects the Growth of Spodoptera litura Fabricius by Inducing Apoptosis in Larval Midgut.

    Science.gov (United States)

    Shu, Benshui; Zhang, Jingjing; Cui, Gaofeng; Sun, Ranran; Yi, Xin; Zhong, Guohua

    2018-01-01

    Azadirachtin, the environmentally friendly botanical pesticide, has been used as an antifeedant and pest growth regulator in integrated pest management for decades. It has shown strong biological activity against Spodoptera litura , but the mechanism of toxicity remains unclear. The present study showed that azadirachtin inhibited the growth of S. litura larvae, which was resulted by structure destroy and size inhibition of the midgut. Digital gene expression (DGE) analysis of midgut suggested that azadirachtin regulated the transcriptional level of multiple unigenes involved in mitogen-activated protein kinase (MAPK) and calcium apoptotic signaling pathways. Simultaneously, the expression patterns of some differentially expressed unigenes were verified by quantitative real time-PCR (qRT-PCR). In addition, the enhanced terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining, the increased expression of caspase family members and apoptosis-binding motif 1 (IBM1) on both gene and protein level and the release of cytochrome c from mitochondria to cytoplasm were induced in midgut after azadirachtin treatment. These results demonstrated that azadirachtin induced structural alteration in S. litura larval midgut by apoptosis activation. These alterations may affect the digestion and absorption of nutrients and eventually lead to the growth inhibition of larvae.

  5. Azadirachtin Affects the Growth of Spodoptera litura Fabricius by Inducing Apoptosis in Larval Midgut

    Directory of Open Access Journals (Sweden)

    Benshui Shu

    2018-02-01

    Full Text Available Azadirachtin, the environmentally friendly botanical pesticide, has been used as an antifeedant and pest growth regulator in integrated pest management for decades. It has shown strong biological activity against Spodoptera litura, but the mechanism of toxicity remains unclear. The present study showed that azadirachtin inhibited the growth of S. litura larvae, which was resulted by structure destroy and size inhibition of the midgut. Digital gene expression (DGE analysis of midgut suggested that azadirachtin regulated the transcriptional level of multiple unigenes involved in mitogen-activated protein kinase (MAPK and calcium apoptotic signaling pathways. Simultaneously, the expression patterns of some differentially expressed unigenes were verified by quantitative real time-PCR (qRT-PCR. In addition, the enhanced terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL staining, the increased expression of caspase family members and apoptosis-binding motif 1 (IBM1 on both gene and protein level and the release of cytochrome c from mitochondria to cytoplasm were induced in midgut after azadirachtin treatment. These results demonstrated that azadirachtin induced structural alteration in S. litura larval midgut by apoptosis activation. These alterations may affect the digestion and absorption of nutrients and eventually lead to the growth inhibition of larvae.

  6. A Study of the Pelagic Larval Duration of Acropora humilis, Coral Recruitment and Connectivity in the Saudi Arabian Red Sea

    KAUST Repository

    Khalil, Maha

    2011-01-01

    Combined knowledge of the pelagic larval duration of coral species and coral recruitment patterns can provide evidence of inter-reef connectivity and indicate a reef’s ability to recover. We attempted to determine the maximum pelagic larval duration

  7. 20-Hydroxyecdysone (20E) Primary Response Gene E93 Modulates 20E Signaling to Promote Bombyx Larval-Pupal Metamorphosis.

    Science.gov (United States)

    Liu, Xi; Dai, Fangyin; Guo, Enen; Li, Kang; Ma, Li; Tian, Ling; Cao, Yang; Zhang, Guozheng; Palli, Subba R; Li, Sheng

    2015-11-06

    As revealed in a previous microarray study to identify genes regulated by 20-hydroxyecdysone (20E) and juvenile hormone (JH) in the silkworm, Bombyx mori, E93 expression in the fat body was markedly low prior to the wandering stage but abundant during larval-pupal metamorphosis. Induced by 20E and suppressed by JH, E93 expression follows this developmental profile in multiple silkworm alleles. The reduction of E93 expression by RNAi disrupted 20E signaling and the 20E-induced autophagy, caspase activity, and cell dissociation in the fat body. Reducing E93 expression also decreased the expression of the 20E-induced pupal-specific cuticle protein genes and prevented growth and differentiation of the wing discs. Importantly, the two HTH domains in E93 are critical for inducing the expression of a subset of 20E response genes, including EcR, USP, E74, Br-C, and Atg1. By contrast, the LLQHLL and PLDLSAK motifs in E93 inhibit its transcriptional activity. E93 binds to the EcR-USP complex via a physical association with USP through its LLQHLL motif; and this association is enhanced by 20E-induced EcR-USP interaction, which attenuates the transcriptional activity of E93. E93 acts through the two HTH domains to bind to GAGA-containing motifs present in the Atg1 promoter region for inducing gene expression. In conclusion, E93 transcriptionally modulates 20E signaling to promote Bombyx larval-pupal metamorphosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. 20-Hydroxyecdysone (20E) Primary Response Gene E93 Modulates 20E Signaling to Promote Bombyx Larval-Pupal Metamorphosis*

    Science.gov (United States)

    Liu, Xi; Dai, Fangyin; Guo, Enen; Li, Kang; Ma, Li; Tian, Ling; Cao, Yang; Zhang, Guozheng; Palli, Subba R.; Li, Sheng

    2015-01-01

    As revealed in a previous microarray study to identify genes regulated by 20-hydroxyecdysone (20E) and juvenile hormone (JH) in the silkworm, Bombyx mori, E93 expression in the fat body was markedly low prior to the wandering stage but abundant during larval-pupal metamorphosis. Induced by 20E and suppressed by JH, E93 expression follows this developmental profile in multiple silkworm alleles. The reduction of E93 expression by RNAi disrupted 20E signaling and the 20E-induced autophagy, caspase activity, and cell dissociation in the fat body. Reducing E93 expression also decreased the expression of the 20E-induced pupal-specific cuticle protein genes and prevented growth and differentiation of the wing discs. Importantly, the two HTH domains in E93 are critical for inducing the expression of a subset of 20E response genes, including EcR, USP, E74, Br-C, and Atg1. By contrast, the LLQHLL and PLDLSAK motifs in E93 inhibit its transcriptional activity. E93 binds to the EcR-USP complex via a physical association with USP through its LLQHLL motif; and this association is enhanced by 20E-induced EcR-USP interaction, which attenuates the transcriptional activity of E93. E93 acts through the two HTH domains to bind to GAGA-containing motifs present in the Atg1 promoter region for inducing gene expression. In conclusion, E93 transcriptionally modulates 20E signaling to promote Bombyx larval-pupal metamorphosis. PMID:26378227

  9. Caffeine induces high expression of cyp-35A family genes and inhibits the early larval development in Caenorhabditis elegans.

    Science.gov (United States)

    Min, Hyemin; Kawasaki, Ichiro; Gong, Joomi; Shim, Yhong-Hee

    2015-03-01

    Intake of caffeine during pregnancy can cause retardation of fetal development. Although the significant influence of caffeine on animal development is widely recognized, much remains unknown about its mode of action because of its pleiotropic effects on living organisms. In the present study, by using Caenorhabditis elegans as a model organism, the effects of caffeine on development were examined. Brood size, embryonic lethality, and percent larval development were investigated, and caffeine was found to inhibit the development of C. elegans at most of the stages in a dosage-dependent fashion. Upon treatment with 30 mM caffeine, the majority (86.1 ± 3.4%) of the L1 larvae were irreversibly arrested without further development. In contrast, many of the late-stage larvae survived and grew to adults when exposed to the same 30 mM caffeine. These results suggest that early-stage larvae are more susceptible to caffeine than later-stage larvae. To understand the metabolic responses to caffeine treatment, the levels of expression of cytochrome P450 (cyp) genes were examined with or without caffeine treatment using comparative micro-array, and it was found that the expression of 24 cyp genes was increased by more than 2-fold (p family was the most prominent. Interestingly, depletion of the cyp-35A family genes one-by-one or in combination through RNA interference resulted in partial rescue from early larval developmental arrest caused by caffeine treatment, suggesting that the high-level induction of cyp-35A family genes can be fatal to the development of early-stage larvae.

  10. Foraging behaviour and prey size spectra of larval herring Clupea harengus

    DEFF Research Database (Denmark)

    Munk, Peter

    1992-01-01

    size groups of larval herring Clupea harengus L. were studied when preying on 6 size groups of copepods. Larval swimming and attack behaviour changed with prey size and were related to the ratio between prey length and larval length. The effective search rate showed a maximum when prey length was about......, that the available biomass of food as a proportion of the predator biomass will not increase. In order to assess the uniformity of relative prey size spectra of herring larvae and their background in larval foraging behaviour, a set of experimental and field investigations has been carried out. In the experiments, 4...... in the biomass spectra of the environment is important to larval growth and survival....

  11. Descriptions of four larval forms of Nilodosis Kieffer from East Asia

    Directory of Open Access Journals (Sweden)

    Hongqu Tang

    2012-10-01

    Full Text Available Larval material putatively assigned to the genus Nilodosis Kieffer from Korea, China and Japan has been compared. The results show that the Japanese larval form has the club- to balloon-shaped cephalic setae S7 and S9 in common with the Korean larval form, but it can be separated from the latter by the shape of the inner mandibular teeth and the premandibular teeth. The larval forms from China (Guangdong and Yunnan apparently consist of two independent species. It is most likely that there will be more species in this genus found in Asia. Larvae are mud-sandy bottom-dwellers that can occur in the littoral of lakes and the potamal of larger rivers, up to a maximum depth of 5 meters. The specific larval characters show that it probably is a semi-psammorheophilic predator. doi: 10.5324/fn.v31i0.1406.Published online: 17 October 2012. 

  12. Determination of the efficiency of diets for larval development in mass rearing Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Gunathilaka, P A D H N; Uduwawala, U M H U; Udayanga, N W B A L; Ranathunge, R M T B; Amarasinghe, L D; Abeyewickreme, W

    2017-11-23

    Larval diet quality and rearing conditions have a direct and irreversible effect on adult traits. Therefore, the current study was carried out to optimize the larval diet for mass rearing of Aedes aegypti, for Sterile Insect Technique (SIT)-based applications in Sri Lanka. Five batches of 750 first instar larvae (L 1) of Ae. aegypti were exposed to five different concentrations (2-10%) of International Atomic Energy Agency (IAEA) recommended the larval diet. Morphological development parameters of larva, pupa, and adult were detected at 24 h intervals along with selected growth parameters. Each experiment was replicated five times. General Linear Modeling along with Pearson's correlation analysis were used for statistical treatments. Significant differences (P rate and success, sex ratio, adult success, fecundity and hatching rate of Ae. aegypti. The best quality adults can be produced at larval diet concentration of 10%. However, the 8% larval diet concentration was most suitable for adult male survival.

  13. Developmental pathways to preference and popularity in middle childhood

    NARCIS (Netherlands)

    Berg, Y.H.M. van den; Deutz, M.H.F.; Smeekens, S.; Cillessen, A.H.N.

    2017-01-01

    This study examined the associations between children's early life experiences with parents, ego resiliency and ego undercontrol, and peer group social status in a longitudinal, multimethod study from infancy to middle childhood. Participants were 129 children (52% boys) who were followed from

  14. Developmental Pathways to Preference and Popularity in Middle Childhood

    NARCIS (Netherlands)

    van den Berg, Yvonne H M; Deutz, Marike H F; Smeekens, Sanny; Cillessen, Antonius H N

    This study examined the associations between children's early life experiences with parents, ego resiliency and ego undercontrol, and peer group social status in a longitudinal, multimethod study from infancy to middle childhood. Participants were 129 children (52% boys) who were followed from 15

  15. The final common pathway in postural control - Developmental perspective

    NARCIS (Netherlands)

    Kernell, D

    A brief review is given concerning postural specialisations among mammalian muscle fibres and motor units. Most skeletal muscles contain a mixture of fibres with different characteristics, and their slow-twitch (S) units are well-known to possess properties suitable for postural tasks: they are

  16. Developmental pathways in food allergy: a new theoretical framework.

    LENUS (Irish Health Repository)

    DunnGalvin, A

    2009-04-01

    To date, there is no model of psychosocial development based on empirical food allergy (FA) research. This limits the ability of clinicians, researchers and policy-makers to predict and evaluate the real impact of FA on the child, with implications for prevention, treatment, intervention and health policy.

  17. Glue protein production can be triggered by steroid hormone signaling independent of the developmental program in Drosophila melanogaster.

    Science.gov (United States)

    Kaieda, Yuya; Masuda, Ryota; Nishida, Ritsuo; Shimell, MaryJane; O'Connor, Michael B; Ono, Hajime

    2017-10-01

    Steroid hormones regulate life stage transitions, allowing animals to appropriately follow a developmental timeline. During insect development, the steroid hormone ecdysone is synthesized and released in a regulated manner by the prothoracic gland (PG) and then hydroxylated to the active molting hormone, 20-hydroxyecdysone (20E), in peripheral tissues. We manipulated ecdysteroid titers, through temporally controlled over-expression of the ecdysteroid-inactivating enzyme, CYP18A1, in the PG using the GeneSwitch-GAL4 system in the fruit fly Drosophila melanogaster. We monitored expression of a 20E-inducible glue protein gene, Salivary gland secretion 3 (Sgs3), using a Sgs3:GFP fusion transgene. In wild type larvae, Sgs3-GFP expression is activated at the midpoint of the third larval instar stage in response to the rising endogenous level of 20E. By first knocking down endogenous 20E levels during larval development and then feeding 20E to these larvae at various stages, we found that Sgs3-GFP expression could be triggered at an inappropriate developmental stage after a certain time lag. This stage-precocious activation of Sgs3 required expression of the Broad-complex, similar to normal Sgs3 developmental regulation, and a small level of nutritional input. We suggest that these studies provide evidence for a tissue-autonomic regulatory system for a metamorphic event independent from the primary 20E driven developmental progression. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. A Marriage Of Larval Modeling And Empirical Data: Linking Adult, Larval And Juvenile Scallops In An Estuary

    Science.gov (United States)

    Bayer, S.; Wahle, R.; Brooks, D. A.; Brady, D. C.

    2016-02-01

    The giant sea scallop, Placopecten magellanicus, is a commercially valuable sedentary broadcast spawner that occupies offshore banks and coastal bays and estuaries in the Northwest Atlantic. Although area closures have helped repopulate depleted scallop populations, little is known about whether populations at densities that yield larvae supply local or distant populations. Surveying scallop populations in the Damariscotta River estuary in Maine during the 2013 and 2014 spawning seasons, and settling out spat bags to collect settling larvae along the gradient of the estuary, we were able to compare adult densities to newly settled juvenile (`spat') abundance. Using the location where we found a high density of adults, we incorporated previously published behavior, pelagic larval duration, wind and current data into a particle dispersal model within the estuary to determine likely sinks for larvae from the 2013 and 2014 spawning seasons. Preliminary model simulations demonstrate where in the estuary swimming is effective in affecting water column position for larvae, and that most larvae are retained much closer to the mouth of the estuary than previously expected. Combining larval dispersal modeling with empirical data on adult densities and spat settlement on the scale of an embayment or estuary may be helpful in determining sources, sinks and areas that are both sources and sinks for shellfish species that are endangered or economically critical. This may aid in determining small area closures or Marine Protected Areas along coastal regions in the Gulf of Maine and beyond.

  19. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Directory of Open Access Journals (Sweden)

    Paula Pappalardo

    Full Text Available 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

  20. Correlated evolution between mode of larval development and habitat in muricid gastropods.

    Science.gov (United States)

    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.

  1. A novel ecdysone receptor mediates steroid-regulated developmental events during the mid-third instar of Drosophila.

    Directory of Open Access Journals (Sweden)

    Benjamin F B Costantino

    2008-06-01

    Full Text Available The larval salivary gland of Drosophila melanogaster synthesizes and secretes glue glycoproteins that cement developing animals to a solid surface during metamorphosis. The steroid hormone 20-hydroxyecdysone (20E is an essential signaling molecule that modulates most of the physiological functions of the larval gland. At the end of larval development, it is known that 20E--signaling through a nuclear receptor heterodimer consisting of EcR and USP--induces the early and late puffing cascade of the polytene chromosomes and causes the exocytosis of stored glue granules into the lumen of the gland. It has also been reported that an earlier pulse of hormone induces the temporally and spatially specific transcriptional activation of the glue genes; however, the receptor responsible for triggering this response has not been characterized. Here we show that the coordinated expression of the glue genes midway through the third instar is mediated by 20E acting to induce genes of the Broad Complex (BRC through a receptor that is not an EcR/USP heterodimer. This result is novel because it demonstrates for the first time that at least some 20E-mediated, mid-larval, developmental responses are controlled by an uncharacterized receptor that does not contain an RXR-like component.

  2. Long-Chain Omega-3 Polyunsaturated Fatty Acids Have Developmental Effects on the Crop Pest, the Cabbage White Butterfly Pieris rapae.

    Directory of Open Access Journals (Sweden)

    Stefanie M Hixson

    Full Text Available Nutritional enhancement of crops using genetic engineering can potentially affect herbivorous pests. Recently, oilseed crops have been genetically engineered to produce the long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA at levels similar to that found in fish oil; to provide a more sustainable source of these compounds than is currently available from wild fish capture. We examined some of the growth and development impacts of adding EPA and DHA to an artificial diet of Pieris rapae, a common pest of Brassicaceae plants. We replaced 1% canola oil with EPA: DHA (11:7 ratio in larval diets, and examined morphological traits and growth of larvae and ensuing adults across 5 dietary treatments. Diets containing increasing amounts of EPA and DHA did not affect developmental phenology, larval or pupal weight, food consumption, nor larval mortality. However, the addition of EPA and DHA in larval diets resulted in progressively heavier adults (F 4, 108 = 6.78; p = 0.011, with smaller wings (p < 0.05 and a higher frequency of wing deformities (R = 0.988; p = 0.001. We conclude that the presence of EPA and DHA in diets of larval P. rapae may alter adult mass and wing morphology; therefore, further research on the environmental impacts of EPA and DHA production on terrestrial biota is advisable.

  3. Regional and seasonal differences in growth of larval North Sea herring (clupea harengus L.) estimated by otolith microstructure analysis

    DEFF Research Database (Denmark)

    Munk, Peter; Heath, Mike; Skaarup, Bo

    1991-01-01

    The ecology processes of the larval life of autumn-spawned North Sea herring have been studied in a multidisciplinary and internationally coordinated research programme (ACE). The programme focused on larval advection and the importance of the autumn/winter circulation in determining larval distr...

  4. Modelling larval transport in a axial convergence front

    Science.gov (United States)

    Robins, P.

    2010-12-01

    Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

  5. Young Children’s Developmental Ecologies and Kindergarten Readiness

    Science.gov (United States)

    Mollborn, Stefanie

    2016-01-01

    Children enter the crucial transition to school with sociodemographic disparities firmly established. Domain-specific research (e.g., on poverty and family structure) has shed light on these disparities, but we need broader operationalizations of children’s environments to explain them. Building on existing theory, this study articulates the concept of developmental ecology—those interrelated features of a child’s proximal environment that shape development and health. Developmental ecology links structural and demographic factors with interactional, psychological, and genetic factors. Using the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), this study conducts latent class analyses to identify how 41 factors from three domains—namely, household resources, health risks, and ecological changes—cluster within children as four overarching developmental ecologies. Because it documents how numerous factors co-occur within children, this method allows an approximation of their lived environments. Findings illuminate powerful relationships between race/ethnicity, parental age, socioeconomic background, and nativity and a child’s developmental ecology, as well as associations between developmental ecology and kindergarten cognition, behavior, and health. Developmental ecology represents a major pathway through which demographic characteristics shape school readiness. Because specific factors have different implications depending on the ecologies in which they are embedded, findings support the usefulness of a broad ecological approach. PMID:27873222

  6. A Transcriptomic Analysis of Echinococcus granulosus Larval Stages: Implications for Parasite Biology and Host Adaptation

    Science.gov (United States)

    Parkinson, John; Wasmuth, James D.; Salinas, Gustavo; Bizarro, Cristiano V.; Sanford, Chris; Berriman, Matthew; Ferreira, Henrique B.; Zaha, Arnaldo; Blaxter, Mark L.; Maizels, Rick M.; Fernández, Cecilia

    2012-01-01

    Background The cestode Echinococcus granulosus - the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide - is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages. Methodology/Principal Findings We generated ∼10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H+-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development. Conclusions/Significance This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome

  7. Topographic processing in developmental prosopagnosia

    DEFF Research Database (Denmark)

    Klargaard, Solja K.; Starrfelt, Randi; Petersen, Anders

    2016-01-01

    deficit in visual processing or visual short-term memory. Interestingly, a classical dissociation could be demonstrated between impaired face memory and preserved topographic memory in two developmental prosopagnosics. We conclude that impairments in topographic memory tend to co-occur with developmental......Anecdotal evidence suggests a relation between impaired spatial (navigational) processing and developmental prosopagnosia. To address this formally, we tested two aspects of topographic processing – that is, perception and memory of mountain landscapes shown from different viewpoints. Participants...

  8. Developmental toxicity of CdTe QDs in zebrafish embryos and larvae

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Junchao; Yu, Yongbo [School of Public Health, Capital Medical University (China); Li, Yang [School of Public Health, Jilin University (China); Yu, Yang; Li, Yanbo; Huang, Peili; Zhou, Xianqing [School of Public Health, Capital Medical University (China); Peng, Shuangqing, E-mail: pengsq@hotmail.com [Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Evaluation and Research Centre for Toxicology (China); Sun, Zhiwei, E-mail: zwsun@ccmu.edu.cn [School of Public Health, Capital Medical University (China)

    2013-07-15

    Quantum dots (QDs) have widely been used in biomedical and biotechnological applications. However, few studies focus on the assessing toxicity of QDs exposure in vivo. In this study, zebrafish embryos were treated with CdTe QDs (4 nm) during 4-96 h post-fertilization (hpf). Mortality, hatching rate, malformation, heart rate, and QDs uptake were detected. We also measured the larval behavior to analyze whether QDs had persistent effects on larvae locomotor activity at 144 hpf. The results showed that as the exposure dosages increased, the hatching rate and heart rate of zebrafish embryos were decreased, while the mortality increased. Exposure to QDs caused embryonic malformations, including head malformation, pericardial edema, yolk sac edema, bent spine, and yolk not depleted. QDs fluorescence was mainly localized in the intestines region. The larval behavior testing showed that the total swimming distance was decreased in a dose-dependent manner. The lowest dose (2.5 nM QDs) produced substantial hyperactivity while the higher doses groups (5, 10, and 20 nM QDs) elicited remarkably hypoactivity in dark periods. In summary, the data of this article indicated that QDs caused embryonic developmental toxicity, resulted in persistent effects on larval behavior.

  9. Developmental toxicity of CdTe QDs in zebrafish embryos and larvae

    International Nuclear Information System (INIS)

    Duan, Junchao; Yu, Yongbo; Li, Yang; Yu, Yang; Li, Yanbo; Huang, Peili; Zhou, Xianqing; Peng, Shuangqing; Sun, Zhiwei

    2013-01-01

    Quantum dots (QDs) have widely been used in biomedical and biotechnological applications. However, few studies focus on the assessing toxicity of QDs exposure in vivo. In this study, zebrafish embryos were treated with CdTe QDs (4 nm) during 4–96 h post-fertilization (hpf). Mortality, hatching rate, malformation, heart rate, and QDs uptake were detected. We also measured the larval behavior to analyze whether QDs had persistent effects on larvae locomotor activity at 144 hpf. The results showed that as the exposure dosages increased, the hatching rate and heart rate of zebrafish embryos were decreased, while the mortality increased. Exposure to QDs caused embryonic malformations, including head malformation, pericardial edema, yolk sac edema, bent spine, and yolk not depleted. QDs fluorescence was mainly localized in the intestines region. The larval behavior testing showed that the total swimming distance was decreased in a dose-dependent manner. The lowest dose (2.5 nM QDs) produced substantial hyperactivity while the higher doses groups (5, 10, and 20 nM QDs) elicited remarkably hypoactivity in dark periods. In summary, the data of this article indicated that QDs caused embryonic developmental toxicity, resulted in persistent effects on larval behavior

  10. Developmental toxicity of CdTe QDs in zebrafish embryos and larvae

    Science.gov (United States)

    Duan, Junchao; Yu, Yongbo; Li, Yang; Yu, Yang; Li, Yanbo; Huang, Peili; Zhou, Xianqing; Peng, Shuangqing; Sun, Zhiwei

    2013-07-01

    Quantum dots (QDs) have widely been used in biomedical and biotechnological applications. However, few studies focus on the assessing toxicity of QDs exposure in vivo. In this study, zebrafish embryos were treated with CdTe QDs (4 nm) during 4-96 h post-fertilization (hpf). Mortality, hatching rate, malformation, heart rate, and QDs uptake were detected. We also measured the larval behavior to analyze whether QDs had persistent effects on larvae locomotor activity at 144 hpf. The results showed that as the exposure dosages increased, the hatching rate and heart rate of zebrafish embryos were decreased, while the mortality increased. Exposure to QDs caused embryonic malformations, including head malformation, pericardial edema, yolk sac edema, bent spine, and yolk not depleted. QDs fluorescence was mainly localized in the intestines region. The larval behavior testing showed that the total swimming distance was decreased in a dose-dependent manner. The lowest dose (2.5 nM QDs) produced substantial hyperactivity while the higher doses groups (5, 10, and 20 nM QDs) elicited remarkably hypoactivity in dark periods. In summary, the data of this article indicated that QDs caused embryonic developmental toxicity, resulted in persistent effects on larval behavior.

  11. The Drosophila T-box transcription factor Midline functions within the Notch–Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc

    Science.gov (United States)

    Das, Sudeshna; Chen, Q. Brent; Saucier, Joseph D.; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M.

    2014-01-01

    We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch–Delta signaling pathway essential for specifying the fates of sensory organ precursor cells. This complements an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in diverse neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch–Delta signaling hierarchy and is essential for maintaining cell viability within by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. PMID:23962751

  12. The Drosophila T-box transcription factor Midline functions within the Notch-Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc.

    Science.gov (United States)

    Das, Sudeshna; Chen, Q Brent; Saucier, Joseph D; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M

    2013-01-01

    We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch-Delta signaling pathway essential for specifying the fates of sensory organ precursor (SOP) cells. These findings complement an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in unique neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch-Delta signaling hierarchy and is essential for maintaining cell viability by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Embryonic and larval development of Brycon amazonicus (SPIX & AGASSIZ, 1829

    Directory of Open Access Journals (Sweden)

    A. C. S. Sampaio Nakauth

    Full Text Available Abstract The objective of this study was to describe the embryonic and larval development of Brycon amazonicus, featuring the main events up to 50 hours after fertilization (AF. The material was provided by the Aquaculture Training, Technology and Production Center, Presidente Figueiredo (AM. The characterization was based on stereomicroscopic examination of the morphology of eggs, embryos and larvae and comparison with the literature. Matrinxã eggs are free, transparent, and spherical, with a perivitelline space of 0.56 ± 0.3 mm. The successive divisions give rise to cells with 64 blastomeres during the first hour AF. The gastrula stage, beginning 02 h 40 min AF, was characterized by progressive regression cells and the formation of the embryonic axis, leading to differentiation of the head and tail 05 h 30 min AF. From 06 to 09 h AF the somites, notochord, otic and optic vesicles and otoliths were observed, in addition to heart rate and the release of the tail. The larvae hatched at 10 h 30 min AF (29.9 °C, with a total length of 3.56 ± 0.46 mm. Between 19 and 30 h AF, we observed 1 pigmentation and gut formation, 2 branchial arches, 3 pectoral fins, 4 a mouth opening and 5 teeth. Cannibalism was initiated earlier (34 h AF which was associated with rapid yolk absorption (more than 90% until 50 h AF, signaling the need for an exogenous nutritional source. The environmental conditions (especially temperature influenced the time course of some events throughout the embryonic and larval development, suggesting the need for further studies on this subject.

  14. Developmental plasticity: Friend or foe?

    Science.gov (United States)

    Michels, Karin B

    2017-01-01

    Developmental plasticity - the concept that adaptation to changing and unfavorable environmental conditions are possible but may come at the price of compromised health potentials - has evolutionary grounding as it facilitates survival but dissents with fundamental evolutionary principles in that it may advance the lesser fit. It is an important cornerstone of the Developmental Origins of Health and Disease (DOHaD). Unlike evolutionary adaptation developmental plasticity may be short-lived and restricted to one or few generations and inheritance is uncertain. Potential mechanisms include epigenetic modifications adopted in utero which may not transmit to the next generation; future insights may allow adjustments of the outcomes of developmental plasticity.

  15. Qualitative methodology in developmental psychology

    DEFF Research Database (Denmark)

    Demuth, Carolin; Mey, Günter

    2015-01-01

    Qualitative methodology presently is gaining increasing recognition in developmental psychology. Although the founders of developmental psychology to a large extent already used qualitative procedures, the field was long dominated by a (post) positivistic quantitative paradigm. The increasing rec...... in qualitative research offers a promising avenue to advance the field in this direction.......Qualitative methodology presently is gaining increasing recognition in developmental psychology. Although the founders of developmental psychology to a large extent already used qualitative procedures, the field was long dominated by a (post) positivistic quantitative paradigm. The increasing...

  16. Aconitase and Developmental End Points as Early Indicators of

    Directory of Open Access Journals (Sweden)

    Oleksandr Vasyliovuch Lozinsky

    2014-03-01

    Full Text Available Background: In this study, the toxicity of the different xenobiotics was tested on the fruit fly Drosophila melanogaster model system. Methods: Fly larvae were raised on food supplemented with xenobiotics at different concentrations (sodium nitroprusside (0.1-1.5 mM, S-nitrosoglutathione (0.5-4 mM, and potassium ferrocyanide (1 mM. Emergence of flies, food intake by larvae, and pupation height preference as well as aconitase activity (in 2-day old flies were measured. Results: Food supplementation with xenobiotics caused a developmental delay in the flies and decreased pupation height. Biochemical analyses of oxidative stress markers and activities of antioxidants and their associated enzymes were carried out on 2-day-old flies emerged from control larvae and larvae fed on food supplemented with chemicals. Larval exposure to chemicals resulted in lower activities of aconitase in flies of both sexes and perturbation in activities of antioxidant enzymes. Conclusions: The results of this study showed that among a variety of parameters tested, aconitase activity, developmental endpoints, and pupation height may be used as reliable early indicators of toxicity caused by different chemicals.

  17. Developmental immunotoxicology of lead

    International Nuclear Information System (INIS)

    Dietert, Rodney R.; Lee, Ji-Eun; Hussain, Irshad; Piepenbrink, Michael

    2004-01-01

    The heavy metal, lead, is a known developmental immunotoxicant that has been shown to produce immune alterations in humans as well as other species. Unlike many compounds that exert adverse immune effects, lead exposure at low to moderate levels does not produce widespread loss of immune cells. In contrast, changes resulting from lead exposure are subtle at the immune cell population level but, nevertheless, can be functionally dramatic. A hallmark of lead-induced immunotoxicity is a pronounced shift in the balance in T helper cell function toward T helper 2 responses at the expense of T helper 1 functions. This bias alters the nature and range of immune responses that can be produced thereby influencing host susceptibility to various diseases. Immunotoxic responses to lead appear to differ across life stages not only quantitatively with regard to dose response, but also qualitatively in terms of the spectrum of immune alterations. Experimental studies in several lab animal species suggest the latter stages of gestation are a period of considerable sensitivity for lead-induced immunotoxicity. This review describes the basic characteristics of lead-induced immunotoxicity emphasizing experimental animal results. It also provides a framework for the consideration of toxicant exposure effects across life stages. The existence of and probable basis for developmental windows of immune hyper-susceptibility are presented. Finally, the potential for lead to serve as a perinatal risk factor for childhood asthma as well as other diseases is considered

  18. Larval settlement and metamorphosis of the mussel Mytilus coruscus in response to monospecific bacterial biofilms.

    Science.gov (United States)

    Yang, Jin-Long; Shen, Pei-Jing; Liang, Xiao; Li, Yi-Feng; Bao, Wei-Yang; Li, Jia-Le

    2013-01-01

    The effects of bacterial biofilms (BFs) on larval settlement and metamorphosis of the mussel, Mytilus coruscus, were investigated in the laboratory. Of nine different isolates, Shewanella sp.1 BF induced the highest percentage of larval settlement and metamorphosis, whereas seven other isolates had a moderate inducing activity and one isolate, Pseudoalteromonas sp. 4, had a no inducing activity. The inducing activity of individual bacterial isolates was not correlated either with their phylogenetic relationship or with the surfaces from which they were isolated. Among the eight bacterial species that demonstrated inducing activity, bacterial density was significantly correlated with the inducing activity for each strain, with the exception of Vibrio sp. 1. The Shewanella sp. 1 BF cue that was responsible for inducing larval settlement and metamorphosis was further investigated. Treatment of the BFs with formalin, antibiotics, ultraviolet irradiation, heat, and ethanol resulted in a significant decrease in their inducing activities and cell survival. BF-conditioned water (CW) did not induce larval metamorphosis, but it triggered larval settlement behavior. A synergistic effect of CW with formalin-fixed Shewanella sp. 1 BF significantly promoted larval metamorphosis. Thus, a cocktail of chemical cues derived from bacteria may be necessary to stimulate larval settlement and metamorphosis in this species.

  19. Trans-life cycle acclimation to experimental ocean acidification affects gastric pH homeostasis and larval recruitment in the sea star Asterias rubens.

    Science.gov (United States)

    Hu, Marian Y; Lein, Etienne; Bleich, Markus; Melzner, Frank; Stumpp, Meike

    2018-04-16

    Experimental simulation of near-future ocean acidification (OA) has been demonstrated to affect growth and development of echinoderm larval stages through energy allocation towards ion and pH compensatory processes. To date, it remains largely unknown how major pH regulatory systems and their energetics are affected by trans-generational exposure to near-future acidification levels. Here we used the common sea star Asterias rubens in a reciprocal transplant experiment comprising different combinations of OA scenarios, in order to study trans-generational plasticity using morphological and physiological endpoints. Acclimation of adults to pH T 7.2 (pCO 2 3500μatm) led to reductions in feeding rates, gonad weight, and fecundity. No effects were evident at moderate acidification levels (pH T 7.4; pCO 2 2000μatm). Parental pre-acclimation to pH T 7.2 for 85 days reduced developmental rates even when larvae were raised under moderate and high pH conditions, whereas pre-acclimation to pH T 7.4 did not alter offspring performance. Microelectrode measurements and pharmacological inhibitor studies carried out on larval stages demonstrated that maintenance of alkaline gastric pH represents a substantial energy sink under acidified conditions that may contribute up to 30% to the total energy budget. Parental pre-acclimation to acidification levels that are beyond the pH that is encountered by this population in its natural habitat (e.g. pH T 7.2) negatively affected larval size and development, potentially through reduced energy transfer. Maintenance of alkaline gastric pH and reductions in maternal energy reserves probably constitute the main factors for a reduced juvenile recruitment of this marine keystone species under simulated OA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Developmental aspects of ADHD

    NARCIS (Netherlands)

    Belle, J. van

    2015-01-01

    It is increasingly recognized that ADHD is a heterogeneous disorder, both in its clinical presentation (phenotype) and the underlying aetiology. This heterogeneity makes it difficult to identify causal pathways that link the phenotype to brain structure and functioning. In an attempt to go beyond

  1. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan; Wang, Hao; Matsumura, Kiyotaka; Qian, Pei-Yuan

    2012-01-01

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  2. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2012-02-13

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  3. Contributions of Anopheles larval control to malaria suppression in tropical Africa: review of achievements and potential.

    Science.gov (United States)

    Walker, K; Lynch, M

    2007-03-01

    Malaria vector control targeting the larval stages of mosquitoes was applied successfully against many species of Anopheles (Diptera: Culicidae) in malarious countries until the mid-20th Century. Since the introduction of DDT in the 1940s and the associated development of indoor residual spraying (IRS), which usually has a more powerful impact than larval control on vectorial capacity, the focus of malaria prevention programmes has shifted to the control of adult vectors. In the Afrotropical Region, where malaria is transmitted mainly by Anopheles funestus Giles and members of the Anopheles gambiae Giles complex, gaps in information on larval ecology and the ability of An. gambiae sensu lato to exploit a wide variety of larval habitats have discouraged efforts to develop and implement larval control strategies. Opportunities to complement adulticiding with other components of integrated vector management, along with concerns about insecticide resistance, environmental impacts, rising costs of IRS and logistical constraints, have stimulated renewed interest in larval control of malaria vectors. Techniques include environmental management, involving the temporary or permanent removal of anopheline larval habitats, as well as larviciding with chemical or biological agents. This present review covers large-scale trials of anopheline larval control methods, focusing on field studies in Africa conducted within the past 15 years. Although such studies are limited in number and scope, their results suggest that targeting larvae, particularly in human-made habitats, can significantly reduce malaria transmission in appropriate settings. These approaches are especially suitable for urban areas, where larval habitats are limited, particularly when applied in conjunction with IRS and other adulticidal measures, such as the use of insecticide treated bednets.

  4. I. DEVELOPMENTAL METHODOLOGY AS A CENTRAL SUBDISCIPLINE OF DEVELOPMENTAL SCIENCE.

    Science.gov (United States)

    Card, Noel A

    2017-06-01

    This first chapter introduces the main goals of the monograph and previews the remaining chapters. The goals of this monograph are to provide summaries of our current understanding of advanced developmental methodologies, provide information that can advance our understanding of human development, identify shortcomings in our understanding of developmental methodology, and serve as a flagpost for organizing developmental methodology as a subdiscipline within the broader field of developmental science. The remaining chapters in this monograph address issues in design (sampling and big data), longitudinal data analysis, and issues of replication and research accumulation. The final chapter describes the history of developmental methodology, considers how the previous chapters in this monograph fit within this subdiscipline, and offers recommendations for further advancement. © 2017 The Society for Research in Child Development, Inc.

  5. Constructivist developmental theory is needed in developmental neuroscience

    Science.gov (United States)

    Arsalidou, Marie; Pascual-Leone, Juan

    2016-12-01

    Neuroscience techniques provide an open window previously unavailable to the origin of thoughts and actions in children. Developmental cognitive neuroscience is booming, and knowledge from human brain mapping is finding its way into education and pediatric practice. Promises of application in developmental cognitive neuroscience rests however on better theory-guided data interpretation. Massive amounts of neuroimaging data from children are being processed, yet published studies often do not frame their work within developmental models—in detriment, we believe, to progress in this field. Here we describe some core challenges in interpreting the data from developmental cognitive neuroscience, and advocate the use of constructivist developmental theories of human cognition with a neuroscience interpretation.

  6. Does white clover (Trifolium repens abundance in temperate pastures determine Sitona obsoletus (Coleoptera: Curculionidae larval populations?

    Directory of Open Access Journals (Sweden)

    Mark Richard McNeill

    2016-09-01

    Full Text Available To determine if host plant abundance determined the size of clover root weevil (CRW Sitona obsoletus larval populations, a study was conducted over four years in plots sown in ryegrass (Lolium perenne (cv. Nui sown at either 6 or 30 kg/ha and white clover (Trifolium repens sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand with % clover measured in autumn (April and spring (September of each year. Overall, mean larval densities measured in spring 2012, 2013, 2014 and 2015 were 310, 38, 59 and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3 and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October larval populations to % white clover measured in each plot in autumn (April found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted

  7. Does White Clover (Trifolium repens) Abundance in Temperate Pastures Determine Sitona obsoletus (Coleoptera: Curculionidae) Larval Populations?

    Science.gov (United States)

    McNeill, Mark R; van Koten, Chikako; Cave, Vanessa M; Chapman, David; Hodgson, Hamish

    2016-01-01

    To determine if host plant abundance determined the size of clover root weevil (CRW) Sitona obsoletus larval populations, a study was conducted over 4 years in plots sown in ryegrass ( Lolium perenne ) (cv. Nui) sown at either 6 or 30 kg/ha and white clover ( Trifolium repens ) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012-2015 were 310, 38, 59, and 31 larvae m -2 , respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted, but the numbers

  8. Inherited Sterility Induced in Progeny of Gamma Irradiated Males Spiny Bollworm, Earias insulana Boisd. II. Effect on Larval and Pupal Mortality, Development and Sex Ratio

    International Nuclear Information System (INIS)

    Amin, A.R.H.; Sallam, H.A.; Mohamed, H.F.

    2010-01-01

    Spiny bollworm, Earias insulana Boisd. adult males were irradiated with sub sterilizing doses of 50,80,100 and 150 Gray (Gy) of gamma radiation. The number of surviving larvae was dose dependant and larval/pupal mortality increased as the dose applied to P1 males was increased. The larval mortality among F3 was reduced compared with that of the F1 and F2. The average developmental time from egg hatch to adult emergence at the four tested doses was slightly affected among the progeny descendant of irradiated P1 males through the three successive generations. The percentage of adult emergence was evidently reduced among F1 and F2 progeny resulting from parental males exposed to the three higher irradiation doses (80,100 and 150 Gy).The sex ratio was slightly altered in favor of males among the majority of all treatments. Raman studies of irradiated and unirradiated stones at different temperatures and irradiation times showed a relation between the bands of scattered peaks corresponding to (OH) stretching modes of vibration with the color changes

  9. Molecular Pathways

    Science.gov (United States)

    Lok, Benjamin H.; Powell, Simon N.

    2012-01-01

    The Rad52 protein was largely ignored in humans and other mammals when the mouse knockout revealed a largely “no-effect” phenotype. However, using synthetic lethal approaches to investigate context dependent function, new studies have shown that Rad52 plays a key survival role in cells lacking the function of the BRCA1-BRCA2 pathway of homologous recombination. Biochemical studies also showed significant differences between yeast and human Rad52, in which yeast Rad52 can promote strand invasion of RPA-coated single-stranded DNA in the presence of Rad51, but human Rad52 cannot. This results in the paradox of how is human Rad52 providing Rad51 function: presumably there is something missing in the biochemical assays that exists in-vivo, but the nature of this missing factor is currently unknown. Recent studies have suggested that Rad52 provides back-up Rad51 function for all members of the BRCA1-BRCA2 pathway, suggesting that Rad52 may be a target for therapy in BRCA pathway deficient cancers. Screening for ways to inhibit Rad52 would potentially provide a complementary strategy for targeting BRCA-deficient cancers in addition to PARP inhibitors. PMID:23071261

  10. Developmentally Appropriate Peace Education Curricula

    Science.gov (United States)

    Lewsader, Joellen; Myers-Walls, Judith A.

    2017-01-01

    Peace education has been offered to children for decades, but those curricula have been only minimally guided by children's developmental stages and needs. In this article, the authors apply their research on children's developmental understanding of peace along with peace education principles and Vygotsky's sociocultural theory to present…

  11. Developmental Kindergarten Program Evaluation Report.

    Science.gov (United States)

    Blois, George T.; Cushing, Katherine S.

    The evaluation of the Developmental Kindergarten (DK) Program at the Harrison School District #2, Colorado Springs, Colorado, involved pre- and post-testing of student academic gains and interviewing of principals and teachers. The program aimed to provide developmentally appropriate activities for students believed to be "at risk" of…

  12. Developmental programming of happiness.

    Science.gov (United States)

    Schmidt, Louis A; Fortier, Paz; Lahat, Ayelet; Tang, Alva; Mathewson, Karen J; Saigal, Saroj; Boyle, Michael H; Van Lieshout, Ryan J

    2017-09-01

    Being born at an extremely low birth weight (ELBW; programming hypotheses. Interfacing prenatal programming and differential susceptibility hypotheses, we tested whether individuals with ELBW in different childhood rearing environments showed different attention biases to positive and negative facial emotions in adulthood. Using the oldest known, prospectively followed cohort of ELBW survivors, we found that relative to normal birth weight controls (NBW; >2,500 grams), ELBW survivors displayed the highest and lowest attention bias to happy faces at age 30-35, depending on whether their total family income at age 8 was relatively low (environmental match) or high (environmental mismatch), respectively. This bias to happy faces was associated with a reduced likelihood of emotional problems. Findings suggest that differential susceptibility to positive emotions may be prenatally programmed, with effects lasting into adulthood. We discuss implications for integrating prenatal programming and differential susceptibility hypotheses, and the developmental origins of postnatal plasticity and resilience. © 2017 Wiley Periodicals, Inc.

  13. Developmental colour agnosia.

    Science.gov (United States)

    van Zandvoort, Martine J E; Nijboer, Tanja C W; de Haan, Edward

    2007-08-01

    Colour agnosia concerns the inability to recognise colours despite intact colour perception, semantic memory for colour information, and colour naming. Patients with selective colour agnosia have been described and the deficit is associated with left hemisphere damage. Here we report a case study of a 43-year-old man who was referred to us with a stroke in his right cerebellar hemisphere. During the standard assessment it transpired that he was unable to name coloured patches. Detailed assessment of his colour processing showed that he suffers from a selective colour agnosia. As he claimed to have had this problem all his life, and the fact that the infratentorial infarct that he had incurred was in an area far away from the brain structures that are known to be involved in colour processing, we suggest that he is the first reported case of developmental colour agnosia.

  14. CEREBELLUM: LINKS BETWEEN DEVELOPMENT, DEVELOPMENTAL DISORDERS AND MOTOR LEARNING

    Directory of Open Access Journals (Sweden)

    Mario U Manto

    2012-01-01

    Full Text Available The study of the links and interactions between development and motor learning has noticeable implications for the understanding and management of neurodevelopmental disorders. This is particularly relevant for the cerebellum which is critical for sensorimotor learning. The olivocerebellar pathway is a key pathway contributing to learning of motor skills. Its developmental maturation and remodelling are being unravelled. Advances in genetics have led to major improvements in our appraisal of the genes involved in cerebellar development, especially studies in mutant mice. Cerebellar neurogenesis is compartmentalized in relationship with neurotransmitter fate. The Engrailed-2 gene is a major actor of the specification of cerebellar cell types and late embryogenic morphogenesis. Math1, expressed by the rhombic lip (RL, is required for the genesis of glutamatergic neurons. Mutants deficient for the transcription factor Ptf1a display a lack of Purkinje cells and gabaergic interneurons. Rora gene contributes to the developmental signalling between granule cells and Purkinje neurons. The expression profile of SHH (Sonic hedgehog in postnatal stages determines the final size/shape of the cerebellum. Genes affecting the development impact upon the physiological properties of the cerebellar circuits. For instance, receptors are developmentally regulated and their action interferes directly with developmental processes. Another field of research which is expanding relates to very preterm neonates. They are at risk for cerebellar lesions, which may themselves impair the developmental events. Very preterm neonates often show sensori-motor deficits, highlighting another major link between impaired development and learning deficiencies. Pathways playing a critical role in cerebellar development are likely to become therapeutical targets for several neurodevelopmental disorders.

  15. [Neurotransmission in developmental disorders].

    Science.gov (United States)

    Takeuchi, Yoshihiro

    2008-11-01

    Attention deficit/hyperactivity disorder (AD/HD) is a heterogeneous developmental disorder with an etiology that is not fully understood. AD/HD has been considered to occur due to a disturbance in cathecholaminergic neurotransmission, with particular emphasis on dopamine. The neurotransmission of dopamine in subcortical regions such as the basal ganglia and limbic areas is synaptic; on the other hand, dopamine neurotransmission in the frontal cortex is quite different, because there are very few dopamine transporters (DAT) in the frontal cortex that allow dopamine to diffuse away from the dopamine synapse ("volume transmission"). It is now clear that noradrenergic neurons play a key regulatory role in dopaminergic function in the frontal cortex. Furthermore, serotonergic neurons exert an inhibitory effect on midbrain dopamine cell bodies, and they have an influence on dopamine release in terminal regions. There is accumulating neurobiological evidence pointing toward a role of the serotonin system in AD/HD. The etiology of autism spectrum disorders (ASD) is still unclear, but information from genetics, neuropathology, brain imaging, and basic neuroscience has provided insights into the understanding of this developmental disorder. In addition to abnormal circuitry in specific limbic and neocortical areas of the cerebral cortex, impairments in brainstem, cerebellar, thalamic, and basal ganglia connections have been reported. Numerous studies have pointed to abnormalities in serotonin and glutamate neurotransmission. Three important aspects involved in the pathophysiology of ASD have been proposed. The first is cell migration, the second is unbalanced excitatory-inhibitory networks, and the third is synapse formation and pruning, the key factors being reelin, neurexin, and neuroligin. Serotonin is considered to play an important role in all of these aspects of the pathophysiology of ASD. Finally, I would like to emphasize that it is crucial in the field of child

  16. The C. elegans embryonic fate specification factor EGL-18 (GATA) is reutilized downstream of Wnt signaling to maintain a population of larval progenitor cells.

    Science.gov (United States)

    Gorrepati, Lakshmi; Eisenmann, David M

    2015-01-01

    In metazoans, stem cells in developing and adult tissues can divide asymmetrically to give rise to a daughter that differentiates and a daughter that retains the progenitor fate. Although the short-lived nematode C. elegans does not possess adult somatic stem cells, the lateral hypodermal seam cells behave in a similar manner: they divide once per larval stage to generate an anterior daughter that adopts a non-dividing differentiated fate and a posterior daughter that retains the seam fate and the ability to divide further. Wnt signaling pathway is known to regulate the asymmetry of these divisions and maintain the progenitor cell fate in one daughter, but how activation of the Wnt pathway accomplished this was unknown. We describe here our recent work that identified the GATA transcription factor EGL-18 as a downstream target of Wnt signaling necessary for maintenance of a progenitor population of larval seam cells. EGL-18 was previously shown to act in the initial specification of the seam cells in the embryo. Thus the acquisition of a Wnt-responsive cis-regulatory module allows an embryonic fate specification factor to be reutilized later in life downstream of a different regulator (Wnt signaling) to maintain a progenitor cell population. These results support the use of seam cell development in C. elegans as a simple model system for studying stem and progenitor cell biology.

  17. MKK3 Was Involved in Larval Settlement of the Barnacle Amphibalanus amphitrite through Activating the Kinase Activity of p38MAPK

    KAUST Repository

    Zhang, Gen

    2013-07-29

    The p38 mitogen-activated protein kinase (p38MAPK) plays a key role in larval settlement of the barnacle Amphibalanus amphitrite. To study the signaling pathway associated with p38MAPK during larval settlement, we sought to identify the upstream kinase of p38MAPK. Three MKKs (MKK3, MKK4 and MKK7) and three MAPKs (p38MAPK, ERK and JNK) in A. amphitrite were cloned and recombinantly expressed in E. coli. Through kinase assays, we found that MKK3, but not MKK4 or MKK7, phosphorylated p38MAPK. Furthermore, MKK3 activity was specific to p38MAPK, as it did not phosphorylate ERK or JNK. To further investigate the functional relationship between MKK3 and p38MAPK in vivo, we studied the localization of phospho-MKK3 (pMKK3) and MKK3 by immunostaining. Consistent with the patterns of p38MAPK and phospho-p38MAPK (pp38MAPK), pMKK3 and MKK3 mainly localized to the antennules of the cyprids. Western blot analysis revealed that pMKK3 levels, like pp38MAPK levels, were elevated at cyprid stage, compared to nauplii and juvenile stages. Moreover, pMKK3 levels increased after treatment with adult barnacle crude extracts, suggesting that MKK3 might mediate the stimulatory effects of adult barnacle extracts on the p38MAPK pathway. © 2013 Zhang et al.

  18. MKK3 Was Involved in Larval Settlement of the Barnacle Amphibalanus amphitrite through Activating the Kinase Activity of p38MAPK

    KAUST Repository

    Zhang, Gen; He, Li-Sheng; Wong, Yue Him; Qian, Pei-Yuan

    2013-01-01

    The p38 mitogen-activated protein kinase (p38MAPK) plays a key role in larval settlement of the barnacle Amphibalanus amphitrite. To study the signaling pathway associated with p38MAPK during larval settlement, we sought to identify the upstream kinase of p38MAPK. Three MKKs (MKK3, MKK4 and MKK7) and three MAPKs (p38MAPK, ERK and JNK) in A. amphitrite were cloned and recombinantly expressed in E. coli. Through kinase assays, we found that MKK3, but not MKK4 or MKK7, phosphorylated p38MAPK. Furthermore, MKK3 activity was specific to p38MAPK, as it did not phosphorylate ERK or JNK. To further investigate the functional relationship between MKK3 and p38MAPK in vivo, we studied the localization of phospho-MKK3 (pMKK3) and MKK3 by immunostaining. Consistent with the patterns of p38MAPK and phospho-p38MAPK (pp38MAPK), pMKK3 and MKK3 mainly localized to the antennules of the cyprids. Western blot analysis revealed that pMKK3 levels, like pp38MAPK levels, were elevated at cyprid stage, compared to nauplii and juvenile stages. Moreover, pMKK3 levels increased after treatment with adult barnacle crude extracts, suggesting that MKK3 might mediate the stimulatory effects of adult barnacle extracts on the p38MAPK pathway. © 2013 Zhang et al.

  19. Reversible Age-Related Phenotypes Induced during Larval Quiescence in C. elegans

    Science.gov (United States)

    Roux, Antoine E.; Langhans, Kelley; Huynh, Walter; Kenyon, Cynthia

    2017-01-01

    Summary Cells can enter quiescent states in which cell cycling and growth are suspended. We find that during a long developmental arrest (quiescence) induced by starvation, newly-hatched C. elegans acquire features associated with impaired proteostasis and aging: mitochondrial fission, ROS production, protein aggregation, decreased proteotoxic-stress resistance, and at the organismal level, decline of mobility and high mortality. All signs of aging but one, the presence of protein aggregates, were reversed upon return to development induced by feeding. The endoplasmic reticulum receptor IRE-1 is completely required for recovery, and the downstream transcription factor XBP-1, as well as a protein kinase, KGB-1, are partially required. Interestingly, kgb-1(−) mutants that do recover fail to reverse aging-like mitochondrial phenotypes and have a short adult lifespan. Our study describes the first pathway that reverses phenotypes of aging at the exit of prolonged quiescence. PMID:27304510

  20. Community College Pathways: A Descriptive Report of Summative Assessments and Student Learning

    Science.gov (United States)

    Strother, Scott; Sowers, Nicole

    2014-01-01

    Carnegie's Community College Pathways (CCP) offers two pathways, Statway® and Quantway®, that reduce the amount of time required to complete developmental mathematics and earn college-level mathematics credit. The Pathways aim to improve student success in mathematics while maintaining rigorous content, pedagogy, and learning outcomes. It is…

  1. The extracellular matrix of plants: Molecular, cellular and developmental biology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    A symposium entitled ``The Extracellular Matrix of Plants: Molecular, Cellular and Developmental Biology was held in Tamarron, Colorado, March 15--21, 1996. The following topics were explored in addresses by 43 speakers: structure and biochemistry of cell walls; biochemistry, molecular biology and biosynthesis of lignin; secretory pathway and synthesis of glycoproteins; biosynthesis of matrix polysaccharides, callose and cellulose; role of the extracellular matrix in plant growth and development; plant cell walls in symbiosis and pathogenesis.

  2. INFLUENCE OF LARVAL REARING DIET ACIDITY ON THE QUANTITY AND QUALITY YIELD OF THE MEDITERRANEAN FRUIT FLY CERATITIS CAPITATA (Wied.) (DIPTERA: TEPHRITIDAE) FOR ITS CONTROL BY STERILE INSECT TECHNIQUE (SIT)

    International Nuclear Information System (INIS)

    SHOMAN, A.A.; EL-KHOLY, E.M.S.

    2008-01-01

    The biological effects of larval rearing diet acidity on the developmental stages of the medfly C. capitata (Wied.) were studied at the laboratory scale. Diets were formulated at five different initial pH ranging from 4.59 to 2.09 together with the control group currently used in our laboratory (5.26). These effects were evaluated on larval period, percent pupal recovery, pupal weight, percent adult emergence, percent male production and adult flight ability. The results showed that the shortest larval development occurred at pH 3.48 and 3.75, the highest pupal recovery at pH 3.75, the best pupal weight at pH 2.09, 3.48, 3.75 and 4.59, the highest percent adult emergence at pH 3.75, the highest percentage male production at pH 3.48, and the best percentage of fliers at pH 4.59. The obtained data referred to the optimizing physiochemical factors such as pH can improve the overall yield of mass reared medfly in the laboratory to be irradiated by gamma radiation and released in the field for controlling the insect

  3. Observations on the reproductive and larval biology of Blennius pavo (Pisces: Teleostei)

    Science.gov (United States)

    Westernhagen, H.

    1983-09-01

    Social behaviour and spawning of adult Blennius pavo kept in the laboratory are described. Eggs are deposited in batches on the walls of artificial spawning places (PVC pipes). One male guards and tends the eggs of different females in one spawning place. Larval hatching occurs in groups according to oviposition. Minimum incubation temperature is around 14 15°C. Larval survival in 1-1 rearing jars is not related to larval total length but to density of larval stock. An experimental population of laboratory reared juvenile and adolescent B. pavo displays a male to female ratio of 1:1.4. Factors possibly influencing the sex ratio of this littoral fish are discussed in view of the situation in its natural environment.

  4. Diel and Lunar Variations in Larval Fish Supply in Malindi Marine ...

    African Journals Online (AJOL)

    2Department of Fisheries and Aquatic Sciences, University of Eldoret, PO Box 1125, Eldoret, Kenya; ... in fish larval occurrence was thus studied in Malindi Marine Park, Kenya, to assess diel and lunar ..... New South Wales University Press,.

  5. Quantitative proteomics identify molecular targets that are crucial in larval settlement and metamorphosis of bugula neritina

    KAUST Repository

    Zhang, Huoming; Wong, Yuehim; Wang, Hao; Chen, Zhangfan; Arellano, Shawn M.; Ravasi, Timothy; Qian, Peiyuan

    2011-01-01

    The marine invertebrate Bugula neritina has a biphasic life cycle that consists of a swimming larval stage and a sessile juvenile and adult stage. The attachment of larvae to the substratum and their subsequent metamorphosis have crucial ecological

  6. Circatrigintan instead of lunar periodicity of larval release in a brooding coral species.

    Science.gov (United States)

    Linden, Bart; Huisman, Jef; Rinkevich, Baruch

    2018-04-04

    Larval release by brooding corals is often assumed to display lunar periodicity. Here, we show that larval release of individual Stylophora pistillata colonies does not comply with the assumed tight entrainment by the lunar cycle, and can better be classified as a circatrigintan pattern. The colonies exhibited three distinct reproductive patterns, characterized by short intervals, long intervals and no periodicity between reproductive peaks, respectively. Cross correlation between the lunar cycle and larval release of the periodic colonies revealed an approximately 30-day periodicity with a variable lag of 5 to 10 days after full moon. The observed variability indicates that the lunar cycle does not provide a strict zeitgeber. Other factors such as water temperature and solar radiation did not correlate significantly with the larval release. The circatrigintan patterns displayed by S. pistillata supports the plasticity of corals and sheds new light on discussions on the fecundity of brooding coral species.

  7. AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

  8. When similar beginnings lead to different ends: Constraints and diversity i cirripede larval development

    DEFF Research Database (Denmark)

    Høeg, Jens Thorvald; Møller, Ole Sten

    2006-01-01

    Cirripedes are fascinating models for studying both functional constraints and diversity in larval development. Adult cirripedes display an amazing variation in morphology from sessile suspension feeders that still retain many crustacean characters to parasites that have lost virtually all...

  9. Strengthened currents override the effect of warming on lobster larval dispersal and survival

    NARCIS (Netherlands)

    Cetina-Heredia, Paulina; Roughan, Moninya; van Sebille, Erik; Feng, Ming; Coleman, Melinda A.

    2015-01-01

    Human-induced climate change is projected to increase ocean temperature and modify circulation patterns, with potential widespread implications for the transport and survival of planktonic larvae of marine organisms. Circulation affects the dispersal of larvae, whereas temperature impacts larval

  10. Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

    Science.gov (United States)

    Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

  11. Seasonal variability in penaeid prawn larval abundance in the Mandovi and Zuari estuaries, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.; Goswami, U.

    more in the bottom samples. Based on larval density, M. dobsoni appeared to be a continuous breeder. The active spawning periods in other species were during the late postmonsoon and premonsoon seasons varying with the species. Peak recruitment...

  12. Relevance of biofilm bacteria in modulating the larval metamorphosis of Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.; Raghukumar, S.

    Balanus amphitrite, on its larval metamorphosis. The effect of multispecies bacterial film was also assessed. The production of different molecules by the bacteria was influenced by the nutrient media under which they were grown. It was observed...

  13. Role of serotonergic neurons in the Drosophila larval response to light

    Directory of Open Access Journals (Sweden)

    Campos Ana

    2009-06-01

    Full Text Available Abstract Background Drosophila larval locomotion consists of forward peristalsis interrupted by episodes of pausing, turning and exploratory behavior (head swinging. This behavior can be regulated by visual input as seen by light-induced increase in pausing, head swinging and direction change as well as reduction of linear speed that characterizes the larval photophobic response. During 3rd instar stage, Drosophila larvae gradually cease to be repelled by light and are photoneutral by the time they wander in search for a place to undergo metamorphosis. Thus, Drosophila larval photobehavior can be used to study control of locomotion. Results We used targeted neuronal silencing to assess the role of candidate neurons in the regulation of larval photobehavior. Inactivation of DOPA decarboxylase (Ddc neurons increases the response to light throughout larval development, including during the later stages of the 3rd instar characterized by photoneutral response. Increased response to light is characterized by increase in light-induced direction change and associated pause, and reduction of linear movement. Amongst Ddc neurons, suppression of the activity of corazonergic and serotonergic but not dopaminergic neurons increases the photophobic response observed during 3rd instar stage. Silencing of serotonergic neurons does not disrupt larval locomotion or the response to mechanical stimuli. Reduced serotonin (5-hydroxytryptamine, 5-HT signaling within serotonergic neurons recapitulates the results obtained with targeted neuronal silencing. Ablation of serotonergic cells in the ventral nerve cord (VNC does not affect the larval response to light. Similarly, disruption of serotonergic projections that contact the photoreceptor termini in the brain hemispheres does not impact the larval response to light. Finally, pan-neural over-expression of 5-HT1ADro receptors, but not of any other 5-HT receptor subtype, causes a significant decrease in the response to

  14. In vitro development of Strongylus edentatus to the fourth larval stage with notes on Strongylus vulgaris and Strongylus equinus.

    Science.gov (United States)

    Farrar, R G; Klei, T R

    1985-08-01

    Strongylus edentatus was successfully cultured in vitro to the fourth larval stage (L4). Some growth continued for periods of 40-50 days at which time reductions in viability were observed in some of the culture systems tested. Various combinations of media, sera, buffers and organ explant cultures were tested. All cultures were incubated at 37 C in an atmosphere of 95% air and 5% CO2. Larvae underwent growth and differentiation to the L4 in all medium-serum combinations with and without organ explant cultures. Development and growth did occur but viability was reduced to insignificant levels in media without serum or cells. Optimal growth, differentiation, and longevity were observed in bicarbonate buffered RPMI-1640 containing 10% fetal calf serum and gerbil (Meriones unguiculatus) cecum explant cultures. Observations indicated that Strongylus vulgaris and Strongylus equinus also developed to the L4 stage using similar techniques. However, viability of S. vulgaris L4 was markedly limited. Specific morphological changes marked phases of development of S. edentatus, categorized as early, middle and late third stage, third molt and early fourth stage. Strongylus equinus appeared to follow the same developmental pattern in vitro as S. edentatus. Distinct differences in morphological features during differentiation were observed between S. edentatus and S. vulgaris.

  15. Yellow perch embryo-larval survival and growth in surface waters associated with oil-sands mining

    International Nuclear Information System (INIS)

    Peters, L.E.; Heuvel, M.R. van den; Dixon, D.G.; Power, M.; Boerger, H.; MacKinnon, M.D.; Meer, T. Van

    1995-01-01

    As part of their land reclamation strategy, Syncrude Canada Ltd. is currently developing environmentally acceptable tailings disposal methods. Fine tailings, a suspension of clay and residual bitumen, is the waste product from oil sands extraction. Fine-tailings contain naphthenic acids, a group of saturated aliphatic and alicyclic carboxylic acids, which occur naturally in petroleum and are partly responsible for the toxicity of process water. The wet landscape method involves covering fine tails with a layer of water such that a self-sustaining ecosystem can be established. A 5 ha demonstration pond with a bottom of fine-tailings was constructed and stocked with yellow perch for experimental purposes. Two other reclaimed ponds formed with oil-sands overburden material were also stocked with perch. Adult perch sampled in the fall of 1995 from the experimental and reclaimed ponds exhibited a 2-fold induction of MFO activity compared to the source lake; indicating organic compound exposure. Perch from one of the reclaimed ponds showed significantly reduced circulating reproductive hormone levels, gonad size and smaller ovarian follicles. Reproductive parameters were not different between the source lake and the remaining ponds. Paired lab and field experiments were conducted to determine if contaminants present would be detrimental to egg viability and development of larvae either through direct exposure of spawned eggs or indirectly by effecting oogenesis. An early life stage toxicity test was also performed using commercially available naphthenic acid standard. Endpoints measured were percent fertilization, percent hatch, mortality, deformities, timing of developmental periods and larval growth

  16. Heterochrony in mandible development of larval shrimp (Decapoda: Caridea)--a comparative morphological SEM study of two carideans.

    Science.gov (United States)

    Batel, Annika; Melzer, Roland R; Anger, Klaus; Geiselbrecht, Hannes

    2014-11-01

    Mandible development in the larval stages I-V of two palaemonid shrimp species, Palaemon elegans and Macrobrachium amazonicum, was analyzed using scanning electron microscopy, light microscopy, and confocal laser scanning microscopy. In contrast to the zoea I of P. elegans, first-stage larvae of M. amazonicum are nonfeeding. At hatching, the morphology of the mandibles is fully expressed in P. elegans, while it appears underdeveloped in M. amazonicum, presenting only small precursors of typical caridean features. In successive zoeal stages, both species show similar developmental changes, but the mandibular characters of the larvae in M. amazonicum were delayed compared to the equivalent stages in P. elegans, especially in the development of submarginal setae and mandible size. In conclusion, our results indicate heterochrony (postdisplacement) of mandible development in M. amazonicum compared to that in P. elegans, which is related to initial lack of mandible functionality or planktivorous feeding at hatching, respectively. This conclusion is supported by comparison with other palaemonid zoeae exhibiting different feeding modes. Our data suggest that an evolutionary ground pattern of mandible morphology is present even in species with nonfeeding first-stage larvae. © 2014 Wiley Periodicals, Inc.

  17. Nanos-mediated repression of hid protects larval sensory neurons after a global switch in sensitivity to apoptotic signals.

    Science.gov (United States)

    Bhogal, Balpreet; Plaza-Jennings, Amara; Gavis, Elizabeth R

    2016-06-15

    Dendritic arbor morphology is a key determinant of neuronal function. Once established, dendrite branching patterns must be maintained as the animal develops to ensure receptive field coverage. The translational repressors Nanos (Nos) and Pumilio (Pum) are required to maintain dendrite growth and branching of Drosophila larval class IV dendritic arborization (da) neurons, but their specific regulatory role remains unknown. We show that Nos-Pum-mediated repression of the pro-apoptotic gene head involution defective (hid) is required to maintain a balance of dendritic growth and retraction in class IV da neurons and that upregulation of hid results in decreased branching because of an increase in caspase activity. The temporal requirement for nos correlates with an ecdysone-triggered switch in sensitivity to apoptotic stimuli that occurs during the mid-L3 transition. We find that hid is required during pupariation for caspase-dependent pruning of class IV da neurons and that Nos and Pum delay pruning. Together, these results suggest that Nos and Pum provide a crucial neuroprotective regulatory layer to ensure that neurons behave appropriately in response to developmental cues. © 2016. Published by The Company of Biologists Ltd.

  18. Larval tolerance to salinity in three species of Australian anuran: an indication of saline specialisation in Litoria aurea.

    Directory of Open Access Journals (Sweden)

    Brian D Kearney

    Full Text Available Recent anthropogenic influences on freshwater habitats are forcing anuran populations to rapidly adapt to high magnitude changes in environmental conditions or face local extinction. We examined the effects of ecologically relevant elevated salinity levels on larval growth, metamorphosis and survival of three species of Australian anuran; the spotted marsh frog (Limnodynastes tasmaniensis, the painted burrowing frog (Neobatrachus sudelli and the green and golden bell frog (Litoria aurea, in order to better understand the responses of these animals to environmental change. Elevated salinity (16% seawater negatively impacted on the survival of L. tasmaniensis (35% survival and N sudelli (0% survival, while reduced salinity had a negative impact on L. aurea. (16% seawater: 85% survival; 0.4% seawater: 35% survival. L. aurea tadpoles survived in salinities much higher than previously reported for this species, indicating the potential for inter-populations differences in salinity tolerance. In L. tasmaniensis and L. aurea, development to metamorphosis was fastest in low and high salinity treatments suggesting it is advantageous for tadpoles to invest energy in development in both highly favourable and developmentally challenging environments. We propose that this response might either maximise potential lifetime fecundity when tadpoles experience favourable environments, or, facilitate a more rapid escape from pond environments where there is a reduced probability of survival.

  19. In situ developmental responses of tropical sea urchin larvae to ocean acidification conditions at naturally elevated pCO2 vent sites.

    Science.gov (United States)

    Lamare, Miles D; Liddy, Michelle; Uthicke, Sven

    2016-11-30

    Laboratory experiments suggest that calcifying developmental stages of marine invertebrates may be the most ocean acidification (OA)-sensitive life-history stage and represent a life-history bottleneck. To better extrapolate laboratory findings to future OA conditions, developmental responses in sea urchin embryos/larvae were compared under ecologically relevant in situ exposures on vent-elevated pCO 2 and ambient pCO 2 coral reefs in Papua New Guinea. Echinometra embryos/larvae were reared in meshed chambers moored in arrays on either venting reefs or adjacent non-vent reefs. After 24 and 48 h, larval development and morphology were quantified. Compared with controls (mean pH (T) = 7.89-7.92), larvae developing in elevated pCO 2 vent conditions (pH (T) = 7.50-7.72) displayed a significant reduction in size and increased abnormality, with a significant correlation of seawater pH with both larval size and larval asymmetry across all experiments. Reciprocal transplants (embryos from vent adults transplanted to control conditions, and vice versa) were also undertaken to identify if adult acclimatization can translate resilience to offspring (i.e. transgenerational processes). Embryos originating from vent adults were, however, no more tolerant to reduced pH. Sea temperature and chlorophyll-a concentrations (i.e. larval nutrition) did not contribute to difference in larval size, but abnormality was correlated with chlorophyll levels. This study is the first to examine the response of marine larvae to OA scenarios in the natural environment where, importantly, we found that stunted and abnormal development observed in situ are consistent with laboratory observations reported in sea urchins, in both the direction and magnitude of the response. © 2016 The Author(s).

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

    Directory of Open Access Journals (Sweden)

    Takken Willem

    2010-01-01

    Full Text Available Abstract 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 Metarhizium anisopliae. Anopheles stephensi and An. gambiae were equally susceptible to each fungus. Older larvae were less likely to die than young larvae (HR 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 increase and decrease in mortality rate, respectively, because the spores clumped together. As a result spores did not provide uniform coverage over space and time. It is, therefore, necessary to develop a formulation that allows the spores to spread over the water surface. Apart from formulation appropriate delivery methods are also necessary to avoid exposing non-target organisms to fungus.

  1. Domestic Larval Control Practices and Malaria Prevalence among Under-Five Children in Burkina Faso.

    Directory of Open Access Journals (Sweden)

    Souleymane Diabaté

    Full Text Available Larval source management has contributed to malaria decline over the past years. However, little is known about the impact of larval control practices undertaken at the household level on malaria transmission.The study was conducted in Kaya health district after the 2010 mass distribution of insecticide treated-nets and the initiation of malaria awareness campaigns in Burkina Faso. The aim was to (i estimate the level of domestic larval control practices (cleaning of the house and its surroundings, eradication of larval sources, and elimination of hollow objects that might collect water; (ii identify key determinants; and (iii explore the structural relationships between these practices, participation in awareness-raising activities and mothers' knowledge/attitudes/practices, and malaria prevalence among under-five children.Overall, 2004 households were surveyed and 1,705 under-five children were examined. Half of the mothers undertook at least one action to control larval proliferation. Mothers who had gone to school had better knowledge about malaria and were more likely to undertake domestic larval control practices. Living in highly exposed rural areas significantly decreased the odds of undertaking larval control actions. Mothers' participation in malaria information sessions increased the adoption of vector control actions and bednet use. Malaria prevalence was statistically lower among children in households where mothers had undertaken at least one vector control action or used bed-nets. There was a 0.16 standard deviation decrease in malaria prevalence for every standard deviation increase in vector control practices. The effect of bednet use on malaria prevalence was of the same magnitude.Cleaning the house and its surroundings, eradicating breeding sites, and eliminating hollow objects that might collect water play a substantial role in preventing malaria among under-five. There is a need for national malaria control programs to

  2. Larval nematodes in stomach wall granulomas of smelt Osmerus eperlanus from the German North Sea coast

    OpenAIRE

    Obiekezie, A. I.; Lick, Roland R.; Kerstan, Susanne L.; Möller, Heino

    1992-01-01

    Occurrence of stomach wall granulomas in European smelt was studled at 6 locations along the German North Sea coast. Identification of larval nematodes inhabiting these granulomas is provided for the first time. Three species, isolated by pepsin-HC1 digestion, are involved: Hysterothylacium cf. cornutum, Cosmocephalus obvelatus and Paracuaria tridentata. 72% of all stomachs examined were affected. The ratio of number of granulomas to number of the 3 larval species free in the mesentery was 1:...

  3. Larval transport modeling of deep-sea invertebrates can aid the search for undiscovered populations.

    Directory of Open Access Journals (Sweden)

    Jon M Yearsley

    Full Text Available BACKGROUND: Many deep-sea benthic animals occur in patchy distributions separated by thousands of kilometres, yet because deep-sea habitats are remote, little is known about their larval dispersal. Our novel method simulates dispersal by combining data from the Argo array of autonomous oceanographic probes, deep-sea ecological surveys, and comparative invertebrate physiology. The predicted particle tracks allow quantitative, testable predictions about the dispersal of benthic invertebrate larvae in the south-west Pacific. PRINCIPAL FINDINGS: In a test case presented here, using non-feeding, non-swimming (lecithotrophic trochophore larvae of polyplacophoran molluscs (chitons, we show that the likely dispersal pathways in a single generation are significantly shorter than the distances between the three known population centres in our study region. The large-scale density of chiton populations throughout our study region is potentially much greater than present survey data suggest, with intermediate 'stepping stone' populations yet to be discovered. CONCLUSIONS/SIGNIFICANCE: We present a new method that is broadly applicable to studies of the dispersal of deep-sea organisms. This test case demonstrates the power and potential applications of our new method, in generating quantitative, testable hypotheses at multiple levels to solve the mismatch between observed and expected distributions: probabilistic predictions of locations of intermediate populations, potential alternative dispersal mechanisms, and expected population genetic structure. The global Argo data have never previously been used to address benthic biology, and our method can be applied to any non-swimming larvae of the deep-sea, giving information upon dispersal corridors and population densities in habitats that remain intrinsically difficult to assess.

  4. Attentional networks in developmental dyscalculia

    Directory of Open Access Journals (Sweden)

    Henik Avishai

    2010-01-01

    Full Text Available Abstract Background Very little is known about attention deficits in developmental dyscalculia, hence, this study was designed to provide the missing information. We examined attention abilities of participants suffering from developmental dyscalculia using the attention networks test - interactions. This test was designed to examine three different attention networks--executive function, orienting and alerting--and the interactions between them. Methods Fourteen university students that were diagnosed as suffering from developmental dyscalculia--intelligence and reading abilities in the normal range and no indication of attention-deficit hyperactivity disorder--and 14 matched controls were tested using the attention networks test - interactions. All participants were given preliminary tests to measure mathematical abilities, reading, attention and intelligence. Results The results revealed deficits in the alerting network--a larger alerting effect--and in the executive function networks--a larger congruity effect in developmental dyscalculia participants. The interaction between the alerting and executive function networks was also modulated by group. In addition, developmental dyscalculia participants were slower to respond in the non-cued conditions. Conclusions These results imply specific attentional deficits in pure developmental dyscalculia. Namely, those with developmental dyscalculia seem to be deficient in the executive function and alertness networks. They suffer from difficulty in recruiting attention, in addition to the deficits in numerical processing.

  5. Attentional networks in developmental dyscalculia.

    Science.gov (United States)

    Askenazi, Sarit; Henik, Avishai

    2010-01-07

    Very little is known about attention deficits in developmental dyscalculia, hence, this study was designed to provide the missing information. We examined attention abilities of participants suffering from developmental dyscalculia using the attention networks test - interactions. This test was designed to examine three different attention networks--executive function, orienting and alerting--and the interactions between them. Fourteen university students that were diagnosed as suffering from developmental dyscalculia--intelligence and reading abilities in the normal range and no indication of attention-deficit hyperactivity disorder--and 14 matched controls were tested using the attention networks test-interactions. All participants were given preliminary tests to measure mathematical abilities, reading, attention and intelligence. The results revealed deficits in the alerting network--a larger alerting effect--and in the executive function networks--a larger congruity effect in developmental dyscalculia participants. The interaction between the alerting and executive function networks was also modulated by group. In addition, developmental dyscalculia participants were slower to respond in the non-cued conditions. These results imply specific attentional deficits in pure developmental dyscalculia. Namely, those with developmental dyscalculia seem to be deficient in the executive function and alertness networks. They suffer from difficulty in recruiting attention, in addition to the deficits in numerical processing.

  6. Larval connectivity of pearl oyster through biophysical modelling; evidence of food limitation and broodstock effect

    Science.gov (United States)

    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.

  7. Bioenergetics models to estimate numbers of larval lampreys consumed by smallmouth bass in Elk Creek, Oregon

    Science.gov (United States)

    Schultz, Luke; Heck, Michael; Kowalski, Brandon M; Eagles-Smith, Collin A.; Coates, Kelly C.; Dunham, Jason B.

    2017-01-01

    Nonnative fishes have been increasingly implicated in the decline of native fishes in the Pacific Northwest. Smallmouth Bass Micropterus dolomieu were introduced into the Umpqua River in southwest Oregon in the early 1960s. The spread of Smallmouth Bass throughout the basin coincided with a decline in counts of upstream-migrating Pacific Lampreys Entosphenus tridentatus. This suggested the potential for ecological interactions between Smallmouth Bass and Pacific Lampreys, as well as freshwater-resident Western Brook Lampreys Lampetra richardsoni. To evaluate the potential effects of Smallmouth Bass on lampreys, we sampled diets of Smallmouth Bass and used bioenergetics models to estimate consumption of larval lampreys in a segment of Elk Creek, a tributary to the lower Umpqua River. We captured 303 unique Smallmouth Bass (mean: 197 mm and 136 g) via angling in July and September. We combined information on Smallmouth Bass diet and energy density with other variables (temperature, body size, growth, prey energy density) in a bioenergetics model to estimate consumption of larval lampreys. Larval lampreys were found in 6.2% of diet samples, and model estimates indicated that the Smallmouth Bass we captured consumed 925 larval lampreys in this 2-month study period. When extrapolated to a population estimate of Smallmouth Bass in this segment, we estimated 1,911 larval lampreys were consumed between July and September. Although the precision of these estimates was low, this magnitude of consumption suggests that Smallmouth Bass may negatively affect larval lamprey populations.

  8. Two hemocyte lineages exist in silkworm larval hematopoietic organ.

    Directory of Open Access Journals (Sweden)

    Yuichi Nakahara

    Full Text Available BACKGROUND: Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. METHODOLOGY/PRINCIPAL FINDINGS: To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. CONCLUSIONS/SIGNIFICANCE: From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

  9. Two hemocyte lineages exist in silkworm larval hematopoietic organ.

    Science.gov (United States)

    Nakahara, Yuichi; Kanamori, Yasushi; Kiuchi, Makoto; Kamimura, Manabu

    2010-07-28

    Insects have multiple hemocyte morphotypes with different functions as do vertebrates, however, their hematopoietic lineages are largely unexplored with the exception of Drosophila melanogaster. To study the hematopoietic lineage of the silkworm, Bombyx mori, we investigated in vivo and in vitro differentiation of hemocyte precursors in the hematopoietic organ (HPO) into the four mature hemocyte subsets, namely, plasmatocytes, granulocytes, oenocytoids, and spherulocytes. Five days after implantation of enzymatically-dispersed HPO cells from a GFP-expressing transgenic line into the hemocoel of normal larvae, differentiation into plasmatocytes, granulocytes and oenocytoids, but not spherulocytes, was observed. When the HPO cells were cultured in vitro, plasmatocytes appeared rapidly, and oenocytoids possessing prophenol oxidase activity appeared several days later. HPO cells were also able to differentiate into a small number of granulocytes, but not into spherulocytes. When functionally mature plasmatocytes were cultured in vitro, oenocytoids were observed 10 days later. These results suggest that the hemocyte precursors in HPO first differentiate into plasmatocytes, which further change into oenocytoids. From these results, we propose that B. mori hemocytes can be divided into two major lineages, a granulocyte lineage and a plasmatocyte-oenocytoid lineage. The origins of the spherulocytes could not be determined in this study. We construct a model for the hematopoietic lineages at the larval stage of B. mori.

  10. Demersal and larval fish assemblages in the Chukchi Sea

    Science.gov (United States)

    Norcross, Brenda L.; Holladay, Brenda A.; Busby, Morgan S.; Mier, Kathryn L.

    2010-01-01

    A multidisciplinary research cruise was conducted in the Chukchi Sea in summer 2004 during which we investigated assemblages of small demersal fishes and ichthyoplankton and the water masses associated with these assemblages. This study establishes a baseline of 30 demersal fish and 25 ichthyoplankton taxa in US and Russian waters of the Chukchi Sea. Presence/absence of small demersal fish clustered into four assemblages: Coastal Fishes, Western Chukchi Fishes, South Central Chukchi Fishes, and North Central Chukchi Fishes. Habitats occupied by small demersal fishes were characterized by sediment type, bottom salinity, and bottom temperature. Abundance of ichthyoplankton grouped into three assemblages with geographical extent similar to that of the bottom assemblages, except that there was a single assemblage for Central Chukchi Fishes. Water-column temperature and salinity characterized ichthyoplankton habitats. Three water masses, Alaska Coastal Water, Bering Sea Water, and Winter Water, were identified from both bottom and depth-averaged water-column temperature and salinity. A fourth water mass, Resident Chukchi Water, was identified only in the bottom water. The water mass and habitat characteristics with which demersal and larval fish assemblages were associated create a baseline to measure anticipated effects of climate change that are expected to be most severe at high latitudes. Monitoring fish assemblages could be a tool for assessing the effects of climate change. Climate-induced changes in distributions of species would result in a restructuring of fish assemblages in the Chukchi Sea.

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

    Science.gov (United States)

    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. © 2015 The Fisheries Society of the British Isles.

  12. Preference for and learning of amino acids in larval Drosophila

    Directory of Open Access Journals (Sweden)

    Nana Kudow

    2017-03-01

    Full Text Available Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.

  13. Interactive effects of maternal and environmental exposure to coal combustion wastes decrease survival of larval southern toads (Bufo terrestris)

    International Nuclear Information System (INIS)

    Metts, Brian S.; Buhlmann, Kurt A.; Scott, David E.; Tuberville, Tracey D.; Hopkins, William A.

    2012-01-01

    We conducted a mesocosm study to assess the individual and interactive effects of previous maternal exposure and larval exposure to trace element-laden sediments on southern toads (Bufo terrestris). Previous maternal exposure to coal combustion wastes (CCW) reduced larval survival to metamorphosis up to 57% compared to larvae of unexposed females. Larvae reared on CCW accumulated significant concentrations of trace elements resulting in extended larval periods, reduced growth rates, and reduced mass at metamorphosis. However, the effects were dependent on age of sediments, suggesting the effects of contaminants from CCW may be partially ameliorated over time through the reduced bioavailability of trace elements in aged CCW. Most importantly, maternal exposure to contaminants coupled with larval exposure to fresh CCW interacted to reduce survival to metamorphosis by 85% compared to reference conditions. Our study yields further evidence that disposal of CCW in aquatic basins potentially creates ecological traps for some amphibian populations. - Highlights: ► The interaction of maternal exposure and larval exposure to CCW reduced survival. ► Previous maternal exposure to CCW had a latent effect on survival to metamorphosis. ► Larval southern toads exposed to CCW experienced prolonged larval periods. ► Larval southern toads exposed to CCW had reduced growth rates. ► Larval southern toads exposed to CCW had reduced mass at metamorphosis. - Maternal and environmental exposure to coal combustion wastes interact to decrease survival in larval amphibians.

  14. The Most Developmentally Truncated Fishes Show Extensive Hox Gene Loss and Miniaturized Genomes

    Science.gov (United States)

    Malmstrøm, Martin; Britz, Ralf; Matschiner, Michael; Tørresen, Ole K; Hadiaty, Renny Kurnia; Yaakob, Norsham; Tan, Heok Hui; Jakobsen, Kjetill Sigurd; Salzburger, Walter; Rüber, Lukas

    2018-01-01

    Abstract The world’s smallest fishes belong to the genus Paedocypris. These miniature fishes are endemic to an extreme habitat: the peat swamp forests in Southeast Asia, characterized by highly acidic blackwater. This threatened habitat is home to a large array of fishes, including a number of miniaturized but also developmentally truncated species. Especially the genus Paedocypris is characterized by profound, organism-wide developmental truncation, resulting in sexually mature individuals of <8 mm in length with a larval phenotype. Here, we report on evolutionary simplification in the genomes of two species of the dwarf minnow genus Paedocypris using whole-genome sequencing. The two species feature unprecedented Hox gene loss and genome reduction in association with their massive developmental truncation. We also show how other genes involved in the development of musculature, nervous system, and skeleton have been lost in Paedocypris, mirroring its highly progenetic phenotype. Further, our analyses suggest two mechanisms responsible for the genome streamlining in Paedocypris in relation to other Cypriniformes: severe intron shortening and reduced repeat content. As the first report on the genomic sequence of a vertebrate species with organism-wide developmental truncation, the results of our work enhance our understanding of genome evolution and how genotypes are translated to phenotypes. In addition, as a naturally simplified system closely related to zebrafish, Paedocypris provides novel insights into vertebrate development. PMID:29684203

  15. Developmental Times of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) at Constant Temperatures and Applications in Forensic Entomology.

    Science.gov (United States)

    Yang, Yong-Qiang; Li, Xue-Bo; Shao, Ru-Yue; Lyu, Zhou; Li, Hong-Wei; Li, Gen-Ping; Xu, Lyu-Zi; Wan, Li-Hua

    2016-09-01

    The characteristic life stages of infesting blowflies (Calliphoridae) such as Chrysomya megacephala (Fabricius) are powerful evidence for estimating the death time of a corpse, but an established reference of developmental times for local blowfly species is required. We determined the developmental rates of C. megacephala from southwest China at seven constant temperatures (16-34°C). Isomegalen and isomorphen diagrams were constructed based on the larval length and time for each developmental event (first ecdysis, second ecdysis, wandering, pupariation, and eclosion), at each temperature. A thermal summation model was constructed by estimating the developmental threshold temperature D0 and the thermal summation constant K. The thermal summation model indicated that, for complete development from egg hatching to eclosion, D0 = 9.07 ± 0.54°C and K = 3991.07 ± 187.26 h °C. This reference can increase the accuracy of estimations of postmortem intervals in China by predicting the growth of C. megacephala. © 2016 American Academy of Forensic Sciences.

  16. The Most Developmentally Truncated Fishes Show Extensive Hox Gene Loss and Miniaturized Genomes.

    Science.gov (United States)

    Malmstrøm, Martin; Britz, Ralf; Matschiner, Michael; Tørresen, Ole K; Hadiaty, Renny Kurnia; Yaakob, Norsham; Tan, Heok Hui; Jakobsen, Kjetill Sigurd; Salzburger, Walter; Rüber, Lukas

    2018-04-01

    The world's smallest fishes belong to the genus Paedocypris. These miniature fishes are endemic to an extreme habitat: the peat swamp forests in Southeast Asia, characterized by highly acidic blackwater. This threatened habitat is home to a large array of fishes, including a number of miniaturized but also developmentally truncated species. Especially the genus Paedocypris is characterized by profound, organism-wide developmental truncation, resulting in sexually mature individuals of <8 mm in length with a larval phenotype. Here, we report on evolutionary simplification in the genomes of two species of the dwarf minnow genus Paedocypris using whole-genome sequencing. The two species feature unprecedented Hox gene loss and genome reduction in association with their massive developmental truncation. We also show how other genes involved in the development of musculature, nervous system, and skeleton have been lost in Paedocypris, mirroring its highly progenetic phenotype. Further, our analyses suggest two mechanisms responsible for the genome streamlining in Paedocypris in relation to other Cypriniformes: severe intron shortening and reduced repeat content. As the first report on the genomic sequence of a vertebrate species with organism-wide developmental truncation, the results of our work enhance our understanding of genome evolution and how genotypes are translated to phenotypes. In addition, as a naturally simplified system closely related to zebrafish, Paedocypris provides novel insights into vertebrate development.

  17. The oxylipin pathway in Arabidopsis.

    Science.gov (United States)

    Creelman, Robert A; Mulpuri, Rao

    2002-01-01

    Oxylipins are acyclic or cyclic oxidation products derived from the catabolism of fatty acids which regulate many defense and developmental pathways in plants. The dramatic increase in the volume of publications and reviews on these compounds since 1997 documents the increasing interest in this compound and its role in plants. Research on this topic has solidified our understanding of the chemistry and biosynthetic pathways for oxylipin production. However, more information is still needed on how free fatty acids are produced and the role of beta-oxidation in the biosynthetic pathway for oxylipins. It is also becoming apparent that oxylipin content and composition changes during growth and development and during pathogen or insect attack. Oxylipins such as jasmonic acid (JA) or 12-oxo-phytodienoic acid modulate the expression of numerous genes and influence specific aspects of plant growth, development and responses to abiotic and biotic stresses. Although oxylipins are believed to act alone, several examples were presented to illustrate that JA-induced responses are modulated by the type and the nature of crosstalk with other signaling molecules such as ethylene and salicylic acid. How oxylipins cause changes in gene expression and instigate a physiological response is becoming understood with the isolation of mutations in both positive and negative regulators in the jasmonate signaling pathway and the use of cDNA microarrays.

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

    Science.gov (United States)

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

    2015-02-26

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

  19. Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli; Mok, Flora SY; Wang, Hao; Qian, Pei-Yuan

    2011-01-01

    Background: The metamorphosis of the spionid polychaete Pseudopolydora vexillosa includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of P. vexillosa suggested that little or no de novo protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles. Results: We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes. Conclusion: This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete P. vexillosa. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a

  20. Phosphoproteome analysis during larval development and metamorphosis in the spionid polychaete Pseudopolydora vexillosa

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2011-05-25

    Background: The metamorphosis of the spionid polychaete Pseudopolydora vexillosa includes spontaneous settlement onto soft-bottom habitats and morphogenesis that can be completed in a very short time. A previous study on the total changes to the proteome during the various developmental stages of P. vexillosa suggested that little or no de novo protein synthesis occurs during metamorphosis. In this study, we used multicolor fluorescence detection of proteins in 2-D gels for differential analysis of proteins and phosphoproteins to reveal the dynamics of post-translational modification proteins in this species. A combination of affinity chromatography, 2D-PAGE, and mass spectrometry was used to identify the phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles. Results: We reproducibly detected 210, 492, and 172 phosphoproteins in pre-competent larvae, competent larvae, and newly metamorphosed juveniles, respectively. The highest percentage of phosphorylation was observed during the competent larval stage. About 64 stage-specific phosphoprotein spots were detected in the competent stage, and 32 phosphoproteins were found to be significantly differentially expressed in the three stages. We identified 38 phosphoproteins, 10 of which were differentially expressed during metamorphosis. These phosphoproteins belonged to six categories of biological processes: (1) development, (2) cell differentiation and integrity, (3) transcription and translation, (4) metabolism, (5) protein-protein interaction and proteolysis, and (6) receptors and enzymes. Conclusion: This is the first study to report changes in phosphoprotein expression patterns during the metamorphosis of the marine polychaete P. vexillosa. The higher degree of phosphorylation during the process of attaining competence to settle and metamorphose may be due to fast morphological transitions regulated by various mechanisms. Our data are consistent with previous studies showing a

  1. Quercetin, a natural product supplement, impairs mitochondrial bioenergetics and locomotor behavior in larval zebrafish (Danio rerio).

    Science.gov (United States)

    Zhang, Ji-Liang; Laurence Souders, Christopher; Denslow, Nancy D; Martyniuk, Christopher J

    2017-07-15

    Quercetin is a natural product that is sold as a supplement in health food stores. While there are reported benefits for this flavonoid as a dietary supplement due to antioxidant properties, the full scope of its biological interactions has not been fully addressed. To learn more about the mechanisms of action related to quercetin, we exposed zebrafish (Danio rerio) embryos to 1 and 10μg/L quercetin for 96h starting at 3h post fertilization. Quercetin up to 10μg/L did not induce significant mortality in developing fish, but did increase prevalence of an upward-curved dorsal plane in hatched larvae. To determine whether this developmental defect was potentially related to mitochondrial bioenergetics during development, we measured oxygen consumption rate in whole embryos following a 24-hour exposure to quercetin. Basal mitochondrial and ATP-linked respiration were decreased at 1 and 10μg/L quercetin, and maximal respiration was decreased at 10μg/L quercetin, suggesting that quercetin impairs mitochondrial bioenergetics. This is proposed to be related to the deformities observed during development. Due to the fact that ATP production was affected by quercetin, larval behaviors related to locomotion were investigated, as well as transcriptional responses of six myogenesis transcripts. Quercetin at 10μg/L significantly reduced the swimming velocity of zebrafish larvae. The expression levels of both myostatin A (mstna) and myogenic differentiation (myoD) were also altered by quercetin. Mstna, an inhibitory factor for myogenesis, was significantly increased at 1μg/L quercetin exposure, while myoD, a stimulatory factor for myogenesis, was significantly increased at 10μg/L quercetin exposure. There were no changes in transcripts related to apoptosis (bcl2, bax, casp3, casp7), but we did observe a decrease in mRNA levels for catalase (cat) in fish exposed to each dose, supporting an oxidative stress response. Our data support the hypothesis that quercetin may affect

  2. Developmental transcriptome of Aplysia californica'

    KAUST Repository

    Heyland, Andreas; Vue, Zer; Voolstra, Christian R.; Medina, Mó nica; Moroz, Leonid L.

    2010-01-01

    developmental transcriptome with similar studies in the zebra fish Danio rerio, the fruit fly Drosophila melanogaster, the nematode Caenorhabditis elegans, and other studies on molluscs suggests an overall highly divergent pattern of gene regulatory mechanisms

  3. PREVALENCE AND EFFECT OF DEVELOPMENTAL ...

    African Journals Online (AJOL)

    uvp

    among children might even be higher, as medical and educational systems frequently fail to ... formally diagnosed, but rather described by their teachers as lazy or ..... Developmental Coordination Disorder Questionnaire for Brazilian children.

  4. The Management of Developmental Apraxia.

    Science.gov (United States)

    Gubbay, S. S.

    1978-01-01

    Of 39 children (5-12 years old) with developmental apraxia and agnosia, who were assessed neurologically, 19 were also given simple standarized tests of motor ability. Journal availability: see EC 112 661. (Author/SBH)

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

    Science.gov (United States)

    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

  6. Sequencing and de novo analysis of a coral larval transcriptome using 454 GSFlx

    Directory of Open Access Journals (Sweden)

    Colbourne John K

    2009-05-01

    Full Text Available Abstract Background New methods are needed for genomic-scale analysis of emerging model organisms that exemplify important biological questions but lack fully sequenced genomes. For example, there is an urgent need to understand the potential for corals to adapt to climate change, but few molecular resources are available for studying these processes in reef-building corals. To facilitate genomics studies in corals and other non-model systems, we describe methods for transcriptome sequencing using 454, as well as strategies for assembling a useful catalog of genes from the output. We have applied these methods to sequence the transcriptome of planulae larvae from the coral Acropora millepora. Results More than 600,000 reads produced in a single 454 sequencing run were assembled into ~40,000 contigs with five-fold average sequencing coverage. Based on sequence similarity with known proteins, these analyses identified ~11,000 different genes expressed in a range of conditions including thermal stress and settlement induction. Assembled sequences were annotated with gene names, conserved domains, and Gene Ontology terms. Targeted searches using these annotations identified the majority of genes associated with essential metabolic pathways and conserved signaling pathways, as well as novel candidate genes for stress-related processes. Comparisons with the genome of the anemone Nematostella vectensis revealed ~8,500 pairs of orthologs and ~100 candidate coral-specific genes. More than 30,000 SNPs were detected in the coral sequences, and a subset of these validated by re-sequencing. Conclusion The methods described here for deep sequencing of the transcriptome should be widely applicable to generate catalogs of genes and genetic markers in emerging model organisms. Our data provide the most comprehensive sequence resource currently available for reef-building corals, and include an extensive collection of potential genetic markers for association and

  7. Developmental toxicity of engineered nanomaterials

    DEFF Research Database (Denmark)

    Hougaard, Karin S.; Hansen, Jitka S.; Jackson, Petra

    2016-01-01

    Study of air pollution indicates that minute particles may adversely interfere with pregnancy and fetal development. As engineering of nanoparticles have emerged, so has concern that these might interfere with reproductive and developmental functions. This is because nanotechnology may potentially...... increase the overall particle burden in air and introduce particles with novel characteristics and surface reactivity. To evaluate safety for pregnant women, we have studied developmental toxicity of engineered nanoparticles (ENPs), following exposure of pregnant mice by inhalation (ENPs of titanium...

  8. Can we safely target the WNT pathway?

    Science.gov (United States)

    Kahn, Michael

    2015-01-01

    WNT–β-catenin signalling is involved in a multitude of developmental processes and the maintenance of adult tissue homeostasis by regulating cell proliferation, differentiation, migration, genetic stability and apoptosis, as well as by maintaining adult stem cells in a pluripotent state. Not surprisingly, aberrant regulation of this pathway is therefore associated with a variety of diseases, including cancer, fibrosis and neurodegeneration. Despite this knowledge, therapeutic agents specifically targeting the WNT pathway have only recently entered clinical trials and none has yet been approved. This Review examines the problems and potential solutions to this vexing situation and attempts to bring them into perspective. PMID:24981364

  9. Is the Schwabe Organ a Retained Larval Eye? Anatomical and Behavioural Studies of a Novel Sense Organ in Adult Leptochiton asellus (Mollusca, Polyplacophora Indicate Links to Larval Photoreceptors.

    Directory of Open Access Journals (Sweden)

    Lauren H Sumner-Rooney

    Full Text Available The discovery of a sensory organ, the Schwabe organ, was recently reported as a unifying feature of chitons in the order Lepidopleurida. It is a patch of pigmented tissue located on the roof of the pallial cavity, beneath the velum on either side of the mouth. The epithelium is densely innervated and contains two types of potential sensory cells. As the function of the Schwabe organ remains unknown, we have taken a cross-disciplinary approach, using anatomical, histological and behavioural techniques to understand it. In general, the pigmentation that characterises this sensory structure gradually fades after death; however, one particular concentrated pigment dot persists. This dot is positionally homologous to the larval eye in chiton trochophores, found in the same neuroanatomical location, and furthermore the metamorphic migration of the larval eye is ventral in species known to possess Schwabe organs. Here we report the presence of a discrete subsurface epithelial structure in the region of the Schwabe organ in Leptochiton asellus that histologically resembles the chiton larval eye. Behavioural experiments demonstrate that Leptochiton asellus with intact Schwabe organs actively avoid an upwelling light source, while Leptochiton asellus with surgically ablated Schwabe organs and a control species lacking the organ (members of the other extant order, Chitonida do not (Kruskal-Wallis, H = 24.82, df = 3, p < 0.0001. We propose that the Schwabe organ represents the adult expression of the chiton larval eye, being retained and elaborated in adult lepidopleurans.

  10. The urodelean Mauthner cell. Morphology of the afferent synapses to the M-cell of larval Salamandra salamandra

    Energy Technology Data Exchange (ETDEWEB)

    Cioni, C; De Palma, F; De Vito, L; Stefanelli, A [Rome, Univ. (Italy). Dipt. di Biologia Animale e dell` Uomo

    1998-12-31

    In the present work the fine morphology and the distribution of the afferent synapses to the Mauthner cell of larval Salamandra salamandra are described. The aim of the study is to characterize the synaptic bed in the larvae of this terrestrial salamander in order to compare it with that of larval axolotl and larval anurans. Four main types of afferent endings have been identified: myelinated club endings, round-vesicle end bulbs, flattened-vesicle end bulbs and spiral fibers endings. The M-cell afferent synaptology of larval stages of terrestrial amphibians is quite similar to that previously observed in larval stages of aquatic species. This fact can be related to the fundamental similarities between the larval lifestyles.

  11. The urodelean Mauthner cell. Morphology of the afferent synapses to the M-cell of larval Salamandra salamandra

    Energy Technology Data Exchange (ETDEWEB)

    Cioni, C.; De Palma, F.; De Vito, L.; Stefanelli, A. [Rome, Univ. (Italy). Dipt. di Biologia Animale e dell`Uomo

    1997-12-31

    In the present work the fine morphology and the distribution of the afferent synapses to the Mauthner cell of larval Salamandra salamandra are described. The aim of the study is to characterize the synaptic bed in the larvae of this terrestrial salamander in order to compare it with that of larval axolotl and larval anurans. Four main types of afferent endings have been identified: myelinated club endings, round-vesicle end bulbs, flattened-vesicle end bulbs and spiral fibers endings. The M-cell afferent synaptology of larval stages of terrestrial amphibians is quite similar to that previously observed in larval stages of aquatic species. This fact can be related to the fundamental similarities between the larval lifestyles.

  12. Developmental Science: Past, Present, and Future

    Science.gov (United States)

    Lerner, Richard M.

    2012-01-01

    The goal of developmental science is to describe, explain, and optimize intraindividual changes in adaptive developmental regulations and, as well, interindividual differences in such relations, across life. The history of developmental science is reviewed and its current foci, which are framed by relational developmental systems models that…