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Sample records for caenorhabditis elegans development

  1. Transcriptional network underlying Caenorhabditis elegans vulval development.

    Science.gov (United States)

    Inoue, Takao; Wang, Minqin; Ririe, Ted O; Fernandes, Jolene S; Sternberg, Paul W

    2005-04-05

    The vulval development of Caenorhabditis elegans provides an opportunity to investigate genetic networks that control gene expression during organogenesis. During the fourth larval stage (L4), seven vulval cell types are produced, each of which executes a distinct gene expression program. We analyze how the expression of cell-type-specific genes is regulated. Ras and Wnt signaling pathways play major roles in generating the spatial pattern of cell types and regulate gene expression through a network of transcription factors. One transcription factor (lin-29) primarily controls the temporal expression pattern. Other transcription factors (lin-11, cog-1, and egl-38) act in combination to control cell-type-specific gene expression. The complexity of the network arises in part because of the dynamic nature of gene expression, in part because of the presence of seven cell types, and also because there are multiple regulatory paths for gene expression within each cell type.

  2. Intercellular coupling amplifies fate segregation during Caenorhabditis elegans vulval development.

    Science.gov (United States)

    Giurumescu, Claudiu A; Sternberg, Paul W; Asthagiri, Anand R

    2006-01-31

    During vulval development in Caenorhabditis elegans, six precursor cells acquire a spatial pattern of distinct cell fates. This process is guided by a gradient in the soluble factor, LIN-3, and by direct interactions between neighboring cells mediated by the Notch-like receptor, LIN-12. Genetic evidence has revealed that these two extracellular signals are coupled: lateral cell-cell interactions inhibit LIN-3-mediated signaling, whereas LIN-3 regulates the extent of lateral signaling. To elucidate the quantitative implications of this coupled network topology for cell patterning during vulval development, we developed a mathematical model of LIN-3/LIN-12-mediated signaling in the vulval precursor cell array. Our analysis reveals that coupling LIN-3 and LIN-12 amplifies cellular perception of the LIN-3 gradient and polarizes lateral signaling, both of which enhance fate segregation beyond that achievable by an uncoupled system.

  3. Characterization of seven genes affecting Caenorhabditis elegans hindgut development.

    Science.gov (United States)

    Chamberlin, H M; Brown, K B; Sternberg, P W; Thomas, J H

    1999-01-01

    We have identified and characterized 12 mutations in seven genes that affect the development of the Caenorhabditis elegans hindgut. We find that the mutations can disrupt the postembryonic development of the male-specific blast cells within the hindgut, the hindgut morphology in both males and hermaphrodites, and in some cases, the expression of a hindgut marker in hermaphrodite animals. Mutations in several of the genes also affect viability. On the basis of their mutant phenotypes, we propose that the genes fall into four distinct classes: (1) egl-5 is required for regional identity of the tail; (2) sem-4 is required for a variety of ectodermal and mesodermal cell types, including cells in the hindgut; (3) two genes, lin-49 and lin-59, affect development of many cells, including hindgut; and (4) three genes, mab-9, egl-38, and lin-48, are required for patterning fates within the hindgut, making certain hindgut cells different from others. We also describe a new allele of the Pax gene egl-38 that is temperature sensitive and affects the conserved beta-hairpin of the EGL-38 paired domain. Our results suggest that a combination of different factors contribute to normal C. elegans hindgut development. PMID:10511553

  4. Sphingolipid metabolism regulates development and lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Cutler, Roy G; Thompson, Kenneth W; Camandola, Simonetta; Mack, Kendra T; Mattson, Mark P

    2014-12-15

    Sphingolipids are a highly conserved lipid component of cell membranes involved in the formation of lipid raft domains that house many of the receptors and cell-to-cell signaling factors involved in regulating cell division, maturation, and terminal differentiation. By measuring and manipulating sphingolipid metabolism using pharmacological and genetic tools in Caenorhabditis elegans, we provide evidence that the synthesis and remodeling of specific ceramides (e.g., dC18:1-C24:1), gangliosides (e.g., GM1-C24:1), and sphingomyelins (e.g., dC18:1-C18:1) influence development rate and lifespan. We found that the levels of fatty acid chain desaturation and elongation in many sphingolipid species increased during development and aging, with no such changes in developmentally-arrested dauer larvae or normal adults after food withdrawal (an anti-aging intervention). Pharmacological inhibitors and small interfering RNAs directed against serine palmitoyl transferase and glucosylceramide synthase acted to slow development rate, extend the reproductive period, and increase lifespan. In contrast, worms fed an egg yolk diet rich in sphingolipids exhibited accelerated development and reduced lifespan. Our findings demonstrate that sphingolipid accumulation and remodeling are critical events that determine development rate and lifespan in the nematode model, with both development rate and aging being accelerated by the synthesis of sphingomyelin, and its metabolism to ceramides and gangliosides.

  5. Genes that regulate both development and longevity in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, P.L.; Albert, P.S.; Riddle, D.L. [Univ. of Missouri, Columbia, MO (United States)

    1995-04-01

    The nematode Caenorhabditis elegans responds to conditions of overcrowding and limited food by arresting development as a dauer larva. Genetic analysis of mutations that alter dauer larva formation (daf mutations) is presented along with an updated genetic pathway for dauer vs. nondauer development. Mutations in the daf-2 and daf-23 genes double adult life span, whereas mutations in four other dauer-constitutive genes positioned in a separate branch of this pathway (daf-1, daf-4, daf-7 and daf-8) do not. The increased life spans are suppressed completely by a daf-16 mutation and partially in a daf-2; daf-18 double mutant. A genetic pathway for determination of adult life span is presented based on the same strains and growth conditions used to characterize Daf phenotypes. Both dauer larva formation and adult life span are affected in daf-2; daf-12 double mutants in an allele-specific manner. Mutations in daf-12 do not extend adult life span, but certain combinations of daf-2 and daf-12 mutant alleles nearly quadruple it. This synergistic effect, which does not equivalently extend the fertile period, is the largest genetic extension of life span yet observed in a metazoan. 47 refs., 7 figs., 5 tabs.

  6. Toxicity testing using Caenorhabditis elegans

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    Middendorf, P.J.; Dusenbery, D.B. [Georgia Institute of Technology, Atlanta, GA (United States); Williams, P.L. [Univ. of Georgia, Athens, GA (United States)

    1995-12-31

    Caenorhabditis elegans is a small free-living nematode that is representative of what may be the most abundant animal group. It has been promoted as a possible model organism for toxicity testing in the laboratory and in field evaluations in part because more is known about its biology than any other animal, Toxicity tests using C. elegans have been developed with lethality, reproduction, and behavior as end points. The tests have also been developed to varying degrees using standard laboratory media, water, and soil. The results of the tests when exposing C. elegans to a variety of metals, inorganic, and organic compounds indicate it is typically at least as sensitive as other species currently used, such as Daphnia and earthworms, and is generally much easier to maintain in the laboratory. The advantages and disadvantages of C. elegans and the state of development of the tests will be discussed.

  7. Neural development features: Spatio-temporal development of the Caenorhabditis elegans neuronal network

    CERN Document Server

    Varier, Sreedevi; 10.1371/journal.pcbi.1001044

    2011-01-01

    The nematode Caenorhabditis elegans, with information on neural connectivity, three-dimensional position and cell linage provides a unique system for understanding the development of neural networks. Although C. elegans has been widely studied in the past, we present the first statistical study from a developmental perspective, with findings that raise interesting suggestions on the establishment of long-distance connections and network hubs. Here, we analyze the neuro-development for temporal and spatial features, using birth times of neurons and their three-dimensional positions. Comparisons of growth in C. elegans with random spatial network growth highlight two findings relevant to neural network development. First, most neurons which are linked by long-distance connections are born around the same time and early on, suggesting the possibility of early contact or interaction between connected neurons during development. Second, early-born neurons are more highly connected (tendency to form hubs) than late...

  8. Development of Caenorhabditis elegans pharynx, with emphasis on its nervous system

    Institute of Scientific and Technical Information of China (English)

    Marc PILON; Catarina M(O)RCK

    2005-01-01

    The Caenorhabditis elegans pharynx is a neuromuscular tube of which the function is to pump and crush bacteria, and inject them into the intestine. The 80-cell pharynx develops via the morphogenesis and differentiation of the cells that compose its semi-spherical primordium, and requires the activity of several evolutionarily conserved genes, such as pha-4 (the homolog to the Drosophilaforkhead and vertebrate FoxA), ceh-22 (the homolog to the Drosophila tinman and verte brate Nkx2.5), and pha-2 (the homolog to the vertebrate Hex). There are 20 neurons in the pharynx, each with a reproducible unique trajectory. Developmental genetic analysis of axon guidance in the pharynx indicates that some axon trajectories are in part established without growth cones, whereas other parts necessitate growth cone function and guidance. Here we provide an overview of the developmental genetics of the Caenorhabditis elegans pharynx, with an emphasis on its nervous system.

  9. OSM-11 facilitates LIN-12 Notch signaling during Caenorhabditis elegans vulval development.

    Directory of Open Access Journals (Sweden)

    Hidetoshi Komatsu

    2008-08-01

    Full Text Available Notch signaling is critical for cell fate decisions during development. Caenorhabditis elegans and vertebrate Notch ligands are more diverse than classical Drosophila Notch ligands, suggesting possible functional complexities. Here, we describe a developmental role in Notch signaling for OSM-11, which has been previously implicated in defecation and osmotic resistance in C. elegans. We find that complete loss of OSM-11 causes defects in vulval precursor cell (VPC fate specification during vulval development consistent with decreased Notch signaling. OSM-11 is a secreted, diffusible protein that, like previously described C. elegans Delta, Serrate, and LAG-2 (DSL ligands, can interact with the lineage defective-12 (LIN-12 Notch receptor extracellular domain. Additionally, OSM-11 and similar C. elegans proteins share a common motif with Notch ligands from other species in a sequence defined here as the Delta and OSM-11 (DOS motif. osm-11 loss-of-function defects in vulval development are exacerbated by loss of other DOS-motif genes or by loss of the Notch ligand DSL-1, suggesting that DOS-motif and DSL proteins act together to activate Notch signaling in vivo. The mammalian DOS-motif protein Deltalike1 (DLK1 can substitute for OSM-11 in C. elegans development, suggesting that DOS-motif function is conserved across species. We hypothesize that C. elegans OSM-11 and homologous proteins act as coactivators for Notch receptors, allowing precise regulation of Notch receptor signaling in developmental programs in both vertebrates and invertebrates.

  10. The Nucleolus of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Li-Wei Lee

    2012-01-01

    Full Text Available Nucleolar size and appearance correlate with ribosome biogenesis and cellular activity. The mechanisms underlying changes in nucleolar appearance and regulation of nucleolar size that occur during differentiation and cell cycle progression are not well understood. Caenorhabditis elegans provides a good model for studying these processes because of its small size and transparent body, well-characterized cell types and lineages, and because its cells display various sizes of nucleoli. This paper details the advantages of using C. elegans to investigate features of the nucleolus during the organism's development by following dynamic changes in fibrillarin (FIB-1 in the cells of early embryos and aged worms. This paper also illustrates the involvement of the ncl-1 gene and other possible candidate genes in nucleolar-size control. Lastly, we summarize the ribosomal proteins involved in life span and innate immunity, and those homologous genes that correspond to human disorders of ribosomopathy.

  11. Relationship between mitochondrial electron transport chain dysfunction, development, and life extension in Caenorhabditis elegans.

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    Shane L Rea

    2007-10-01

    Full Text Available Prior studies have shown that disruption of mitochondrial electron transport chain (ETC function in the nematode Caenorhabditis elegans can result in life extension. Counter to these findings, many mutations that disrupt ETC function in humans are known to be pathologically life-shortening. In this study, we have undertaken the first formal investigation of the role of partial mitochondrial ETC inhibition and its contribution to the life-extension phenotype of C. elegans. We have developed a novel RNA interference (RNAi dilution strategy to incrementally reduce the expression level of five genes encoding mitochondrial proteins in C. elegans: atp-3, nuo-2, isp-1, cco-1, and frataxin (frh-1. We observed that each RNAi treatment led to marked alterations in multiple ETC components. Using this dilution technique, we observed a consistent, three-phase lifespan response to increasingly greater inhibition by RNAi: at low levels of inhibition, there was no response, then as inhibition increased, lifespan responded by monotonically lengthening. Finally, at the highest levels of RNAi inhibition, lifespan began to shorten. Indirect measurements of whole-animal oxidative stress showed no correlation with life extension. Instead, larval development, fertility, and adult size all became coordinately affected at the same point at which lifespan began to increase. We show that a specific signal, initiated during the L3/L4 larval stage of development, is sufficient for initiating mitochondrial dysfunction-dependent life extension in C. elegans. This stage of development is characterized by the last somatic cell divisions normally undertaken by C. elegans and also by massive mitochondrial DNA expansion. The coordinate effects of mitochondrial dysfunction on several cell cycle-dependent phenotypes, coupled with recent findings directly linking cell cycle progression with mitochondrial activity in C. elegans, lead us to propose that cell cycle checkpoint control

  12. Interrelationships between mitochondrial fusion, energy metabolism and oxidative stress during development in Caenorhabditis elegans

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    Yasuda, Kayo [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Education and Research Support Center, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Hartman, Philip S. [Biology Department, Texas Christian University, Fort Worth, TX 76129 (United States); Ishii, Takamasa [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Suda, Hitoshi [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan); Akatsuka, Akira [Education and Research Support Center, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Shoyama, Tetsuji [School of High-Technology for Human Welfare, Tokai University, Nishino 317, Numazu, Shizuoka 410-0395 (Japan); Miyazawa, Masaki [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Ishii, Naoaki, E-mail: nishii@is.icc.u-tokai.ac.jp [Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan)

    2011-01-21

    Research highlights: {yields} Growth and development of a fzo-1 mutant defective in the fusion process of mitochondria was delayed relative to the wild type of Caenorhabditis elegans. {yields} Oxygen sensitivity during larval development, superoxide production and carbonyl protein accumulation of the fzo-1 mutant were similar to wild type. {yields} fzo-1 animals had significantly lower metabolism than did N2 and mev-1 overproducing superoxide from mitochondrial electron transport complex II. {yields} Mitochondrial fusion can profoundly affect energy metabolism and development. -- Abstract: Mitochondria are known to be dynamic structures with the energetically and enzymatically mediated processes of fusion and fission responsible for maintaining a constant flux. Mitochondria also play a role of reactive oxygen species production as a byproduct of energy metabolism. In the current study, interrelationships between mitochondrial fusion, energy metabolism and oxidative stress on development were explored using a fzo-1 mutant defective in the fusion process and a mev-1 mutant overproducing superoxide from mitochondrial electron transport complex II of Caenorhabditis elegans. While growth and development of both single mutants was slightly delayed relative to the wild type, the fzo-1;mev-1 double mutant experienced considerable delay. Oxygen sensitivity during larval development, superoxide production and carbonyl protein accumulation of the fzo-1 mutant were similar to wild type. fzo-1 animals had significantly lower metabolism than did N2 and mev-1. These data indicate that mitochondrial fusion can profoundly affect energy metabolism and development.

  13. The multiple faces of calcineurin signaling in Caenorhabditis elegans: Development, behaviour and aging

    Indian Academy of Sciences (India)

    Jin Il Lee; Sutapa Mukherjee; Kyoung–Hye Yoon; Meenakshi Dwivedi; Jaya Bandyopadhyay

    2013-06-01

    Calcineurin, a well-conserved protein phosphatase 2B (PP2B), is a Ca2+-calmodulin–dependent serine/threonine protein phosphatase that is known to be involved in a myriad of cellular processes and signal transduction pathways. The biological role of calcineurin has been extensively studied in diverse groups of organisms. Homologues of mammalian and Drosophila calcineurin subunits exist in the nematode, Caenorhabditis elegans. The C. elegans counterpart of the catalytic subunit, calcineurin A, cna-1/tax-6, and the regulatory subunit, calcineurin B, cnb-1, are known to express ubiquitously in multiple tissues including neurons. The characterization of C. elegans calcineurin mutants facilitates identification of its physiological functions and signaling pathways. Genetic interactions between cna-1/tax-6 and cnb-1 mutants with a number of mutants involved in several signaling pathways have exemplified the pivotal role of calcineurin in regulating nematode development, behaviour and lifespan (aging). The present review has been aimed to provide a succinct summary of the multiple functions of calcineurin in C. elegans relating to its development, fertility, proliferation, behaviour and lifespan. Analyses of cna-1/tax-6 and cnb-1 interacting proteins and regulators of the phosphatase in this fascinating worm model have an immense scope to identify potential drug targets in various parasitic nematodes, which cause many diseases inflicting huge economic loss; and also for many human diseases, particularly neurodegenerative and myocardial diseases.

  14. Intermediate Filaments in Caenorhabditis elegans.

    Science.gov (United States)

    Zuela, Noam; Gruenbaum, Yosef

    2016-01-01

    More than 70 different genes in humans and 12 different genes in Caenorhabditis elegans encode the superfamily of intermediate filament (IF) proteins. In C. elegans, similar to humans, these proteins are expressed in a cell- and tissue-specific manner, can assemble into heteropolymers and into 5-10nm wide filaments that account for the principal structural elements at the nuclear periphery, nucleoplasm, and cytoplasm. At least 5 of the 11 cytoplasmic IFs, as well as the nuclear IF, lamin, are essential. In this chapter, we will include a short review of our current knowledge of both cytoplasmic and nuclear IFs in C. elegans and will describe techniques used for their analyses.

  15. Biolistic transformation of Caenorhabditis elegans

    NARCIS (Netherlands)

    Isik, M.; Berezikov, E.

    2013-01-01

    The ability to generate transgenic animals to study gene expression and function is a powerful and important part of the Caenorhabditis elegans genetic toolbox. Transgenic animals can be created by introducing exogenous DNA into the worm germline either by microinjection or by microparticle bombardm

  16. Application of a mathematical model to describe the effects of chlorpyrifos on Caenorhabditis elegans development.

    Directory of Open Access Journals (Sweden)

    Windy A Boyd

    Full Text Available BACKGROUND: The nematode Caenorhabditis elegans is being assessed as an alternative model organism as part of an interagency effort to develop better means to test potentially toxic substances. As part of this effort, assays that use the COPAS Biosort flow sorting technology to record optical measurements (time of flight (TOF and extinction (EXT of individual nematodes under various chemical exposure conditions are being developed. A mathematical model has been created that uses Biosort data to quantitatively and qualitatively describe C. elegans growth, and link changes in growth rates to biological events. Chlorpyrifos, an organophosphate pesticide known to cause developmental delays and malformations in mammals, was used as a model toxicant to test the applicability of the growth model for in vivo toxicological testing. METHODOLOGY/PRINCIPAL FINDINGS: L1 larval nematodes were exposed to a range of sub-lethal chlorpyrifos concentrations (0-75 microM and measured every 12 h. In the absence of toxicant, C. elegans matured from L1s to gravid adults by 60 h. A mathematical model was used to estimate nematode size distributions at various times. Mathematical modeling of the distributions allowed the number of measured nematodes and log(EXT and log(TOF growth rates to be estimated. The model revealed three distinct growth phases. The points at which estimated growth rates changed (change points were constant across the ten chlorpyrifos concentrations. Concentration response curves with respect to several model-estimated quantities (numbers of measured nematodes, mean log(TOF and log(EXT, growth rates, and time to reach change points showed a significant decrease in C. elegans growth with increasing chlorpyrifos concentration. CONCLUSIONS: Effects of chlorpyrifos on C. elegans growth and development were mathematically modeled. Statistical tests confirmed a significant concentration effect on several model endpoints. This confirmed that chlorpyrifos

  17. A shortcut to identifying small molecule signals that regulate behavior and development in Caenorhabditis elegans.

    Science.gov (United States)

    Pungaliya, Chirag; Srinivasan, Jagan; Fox, Bennett W; Malik, Rabia U; Ludewig, Andreas H; Sternberg, Paul W; Schroeder, Frank C

    2009-05-12

    Small molecule metabolites play important roles in Caenorhabditis elegans biology, but effective approaches for identifying their chemical structures are lacking. Recent studies revealed that a family of glycosides, the ascarosides, differentially regulate C. elegans development and behavior. Low concentrations of ascarosides attract males and thus appear to be part of the C. elegans sex pheromone, whereas higher concentrations induce developmental arrest at the dauer stage, an alternative, nonaging larval stage. The ascarosides act synergistically, which presented challenges for their identification via traditional activity-guided fractionation. As a result the chemical characterization of the dauer and male attracting pheromones remained incomplete. Here, we describe the identification of several additional pheromone components by using a recently developed NMR-spectroscopic approach, differential analysis by 2D NMR spectroscopy (DANS), which simplifies linking small molecule metabolites with their biological function. DANS-based comparison of wild-type C. elegans and a signaling-deficient mutant, daf-22, enabled identification of 3 known and 4 previously undescribed ascarosides, including a compound that features a p-aminobenzoic acid subunit. Biological testing of synthetic samples of these compounds revealed additional evidence for synergy and provided insights into structure-activity relationships. Using a combination of the three most active ascarosides allowed full reconstitution of the male-attracting activity of wild-type pheromone extract. Our results highlight the efficacy of DANS as a method for identifying small-molecule metabolites and placing them within a specific genetic context. This study further supports the hypothesis that ascarosides represent a structurally diverse set of nematode signaling molecules regulating major life history traits.

  18. CCDC-55 is required for larval development and distal tip cell migration in Caenorhabditis elegans.

    Science.gov (United States)

    Kovacevic, Ismar; Ho, Richard; Cram, Erin J

    2012-01-01

    The Caenorhabditis elegans distal tip cells (DTCs) are an in vivo model for the study of developmentally regulated cell migration. In this study, we characterize a novel role for CCDC-55, a conserved coiled-coil domain containing protein, in DTC migration and larval development in C. elegans. Although animals homozygous for a probable null allele, ccdc-55(ok2851), display an early larval arrest, RNAi depletion experiments allow the analysis of later phenotypes and suggest that CCDC-55 is needed within the DTC for migration to cease at the end of larval morphogenesis. The ccdc-55 gene is found in an operon with rnf-121 and rnf-5, E3 ubiquitin ligases that target cell migration genes such as the β-integrin PAT-3. Genetic interaction studies using RNAi depletion and the deletion alleles rnf-121(ok848) and rnf-5(tm794) indicate that CCDC-55 and the RNF genes act at least partially in parallel to promote termination of cell migration in the adult DTC.

  19. Ritmos circadianos en Caenorhabditis elegans

    OpenAIRE

    Migliori, María Laura

    2012-01-01

    Migliori, M. L. (2011). Ritmos circadianos en Caenorhabditis elegans (Tesis de posgrado). Universidad Nacional de Quilmes, Bernal, Argentina. Los ritmos circadianos (del latín circa y dies: cerca de 24 horas) tienen un período de aproximadamente 24 horas y son originados por relojes biológicos que en diversos organismos han podido ser estudiados y caracterizados en detalle. Los ritmos circadianos son endógenos, es decir que se mantienen en ausencia de factores externos. Una importante prop...

  20. Dopamine regulates body size in Caenorhabditis elegans.

    Science.gov (United States)

    Nagashima, Takashi; Oami, Eitaro; Kutsuna, Natsumaro; Ishiura, Shoichi; Suo, Satoshi

    2016-04-01

    The nervous system plays a critical role in the regulation of animal body sizes. In Caenorhabditis elegans, an amine neurotransmitter, dopamine, is required for the tactile perception of food and food-dependent behavioral changes, while its role in development is unknown. In this study, we show that dopamine negatively regulates body size through a D2-like dopamine receptor, DOP-3, in C. elegans. Dopamine alters body size without affecting food intake or developmental rate. We also found that dopamine promotes egg-laying, although the regulation of body size by dopamine was not solely caused by this effect. Furthermore, dopamine negatively regulates body size through the suppression of signaling by octopamine and Gq-coupled octopamine receptors, SER-3 and SER-6. Our results demonstrate that dopamine and octopamine regulate the body size of C. elegans and suggest a potential role for perception in addition to ingestion of food for growth.

  1. Antipsychotic drugs alter neuronal development including ALM neuroblast migration and PLM axonal outgrowth in Caenorhabditis elegans.

    Science.gov (United States)

    Donohoe, Dallas R; Weeks, Kathrine; Aamodt, Eric J; Dwyer, Donard S

    2008-01-01

    Antipsychotic drugs are increasingly being prescribed for children and adolescents, and are used in pregnant women without a clear demonstration of safety in these populations. Global effects of these drugs on neurodevelopment (e.g., decreased brain size) have been reported in rats, but detailed knowledge about neuronal effects and mechanisms of action are lacking. Here we report on the evaluation of a comprehensive panel of antipsychotic drugs in a model organism (Caenorhabditis elegans) that is widely used to study neuronal development. Specifically, we examined the effects of the drugs on neuronal migration and axonal outgrowth in mechanosensory neurons visualized with green fluorescent protein expressed from the mec-3 promoter. Clozapine, fluphenazine, and haloperidol produced deficits in the development and migration of ALM neurons and axonal outgrowth in PLM neurons. The defects included failure of neuroblasts to migrate to the proper location, and excessive growth of axons past their normal termination point, together with abnormal morphological features of the processes. Although the antipsychotic drugs are potent antagonists of dopamine and serotonin receptors, the neurodevelopmental deficits were not rescued by co-incubation with serotonin or the dopaminergic agonist, quinpirole. Other antipsychotic drugs, risperidone, aripiprazole, quetiapine, trifluoperazine and olanzapine, also produced modest, but detectable, effects on neuronal development. This is the first report that antipsychotic drugs interfere with neuronal migration and axonal outgrowth in a developing nervous system.

  2. Visualization and Dissemination of Multidimensional Proteomics Data Comparing Protein Abundance During Caenorhabditis elegans Development

    Science.gov (United States)

    Riffle, Michael; Merrihew, Gennifer E.; Jaschob, Daniel; Sharma, Vagisha; Davis, Trisha N.; Noble, William S.; MacCoss, Michael J.

    2015-11-01

    Regulation of protein abundance is a critical aspect of cellular function, organism development, and aging. Alternative splicing may give rise to multiple possible proteoforms of gene products where the abundance of each proteoform is independently regulated. Understanding how the abundances of these distinct gene products change is essential to understanding the underlying mechanisms of many biological processes. Bottom-up proteomics mass spectrometry techniques may be used to estimate protein abundance indirectly by sequencing and quantifying peptides that are later mapped to proteins based on sequence. However, quantifying the abundance of distinct gene products is routinely confounded by peptides that map to multiple possible proteoforms. In this work, we describe a technique that may be used to help mitigate the effects of confounding ambiguous peptides and multiple proteoforms when quantifying proteins. We have applied this technique to visualize the distribution of distinct gene products for the whole proteome across 11 developmental stages of the model organism Caenorhabditis elegans. The result is a large multidimensional dataset for which web-based tools were developed for visualizing how translated gene products change during development and identifying possible proteoforms. The underlying instrument raw files and tandem mass spectra may also be downloaded. The data resource is freely available on the web at http://www.yeastrc.org/wormpes/.

  3. gld-1, a tumor suppressor gene required for oocyte development in Caenorhabditis elegans

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    Francis, R.; Schedl, T. [Washington Univ. School of Medicine, St. Louis, MO (United States); Barton, M.K.; Kimble, J. [Univ. of Wisconsin, Madison, WI (United States)

    1995-02-01

    We have characterized 31 mutations in the gld-1 (defective in germline development) gene of Caenorhabditis elegans. In gld-1 (null) hermaphrodites, oogenesis is abolished and a germline tumor forms where oocyte development would normally occur. By contrast, gld-1 (null) males are unaffected. The hermaphrodite germline tumor appears to derive from germ cells that enter the meiotic pathway normally but then exit pachytene and return to the mitotic cycle. Certain gld-1 partial loss-of-function mutations also abolish oogenesis, but germ cells arrest in pachytene rather than returning to mitosis. Our results indicate that gld-1 is a tumor suppressor gene required for oocyte development. The tumorous phenotype suggests that gld-1(+) may function to negatively regulate proliferation during meiotic prophase and/or act to direct progression through meiotic prophase. We also show that gld-1(+) has an additional nonessential role in germline sex determination: promotion of hermaphrodite spermatogenesis. This function of gld-1 is inferred from a haplo-insufficient phenotype and from the properties of gain-of-function gld-1 mutations that cause alterations in the sexual identity of germ cells. 69 refs., 10 figs., 8 tabs.

  4. Coordinated morphogenesis of epithelia during development of the Caenorhabditis elegans uterine-vulval connection.

    Science.gov (United States)

    Newman, A P; Sternberg, P W

    1996-01-01

    Development of the nematode egg-laying system requires the formation of a connection between the uterine lumen and the developing vulval lumen, thus allowing a passage for eggs and sperm. This relatively simple process serves as a model for certain aspects of organogenesis. Such a connection demands that cells in both tissues become specialized to participate in the connection, and that the specialized cells are brought in register. A single cell, the anchor cell, acts to induce and to organize specialization of the epidermal and uterine epithelia, and registrates these tissues. The inductions act via evolutionarily conserved intercellular signaling pathways. The anchor cell induces the vulva from ventral epithelial cells via the LIN-3 growth factor and LET-23 transmembrane tyrosine kinase. It then induces surrounding uterine intermediate precursors via the receptor LIN-12, a founding member of the Notch family of receptors. Both signaling pathways are used multiple times during development of Caenorhabditis elegans. The outcome of the signaling is context-dependent. Both inductions are reciprocated. After the anchor cell has induced the vulva, it stretches toward the induced vulval cells. After the anchor cell has induced specialized uterine intermediate precursor cells, it fuses with a subset of their progeny. Images Fig. 1 Fig. 4 PMID:8790329

  5. Acidic intracellular pH shift during Caenorhabditis elegans larval development

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    Wadsworth, W.G.; Riddle, D.L. (Univ. of Missouri, Columbia (USA))

    1988-11-01

    During recovery from the developmentally arrested, nonfeeding dauer stage of the nemotode Caenorhabditis elegans, metabolic activation is accompanied by a decrease in intracellular pH (pH{sub i}). Phosphorus-31 nuclear magnetic resonance ({sup 31}P NMR) analyses of perchloric acid extracts show that inorganic phosphate predominates in dauer larvae, whereas ATP and other high-energy metabolites are abundant within 6 hr after dauer larvae have been placed in food to initiate development. Although metabolic activation has been associated with an alkaline pH{sub i} shift in other organisms, in vivo {sup 31}P NMR analysis of recovering dauer larvae shows a pH{sub i} decrease from {approx} 7.3 to {approx} 6.3 within 3 hr after the animals encounter food. This shift occurs before feeding begins, and it coincides with, or soon follows, the developmental commitment to recover from the dauer stage, suggesting that control of pH{sub i} may be important in the regulation of larval development in nematodes.

  6. The lin-15 locus encodes two negative regulators of Caenorhabditis elegans vulval development.

    Science.gov (United States)

    Huang, L S; Tzou, P; Sternberg, P W

    1994-01-01

    During Caenorhabditis elegans vulval development, an inductive signal from the anchor cell stimulates three of the six vulval precursor cells (VPCs) to adopt vulval rather than nonvulval epidermal fates. Genes necessary for this induction include the lin-3 growth factor, the let-23 receptor tyrosine kinase, and let-60 ras. lin-15 is a negative regulator of this inductive pathway. In lin-15 mutant animals, all six VPCs adopt vulval fates, even in the absence of inductive signal. Previous genetic studies suggested that lin-15 is a complex locus with two independently mutable activities, A and B. We have cloned the lin-15 locus by germline transformation and find that it encodes two nonoverlapping transcripts that are transcribed in the same direction. The downstream transcript encodes the lin-15A function; the upstream transcript encodes the lin-15B function. The predicted lin-15A and lin-15B proteins are novel and hydrophilic. We have identified a molecular null allele of lin-15 and have used it to analyze the role of lin-15 in the signaling pathway. We find that lin-15 acts upstream of let-23 and in parallel to the inductive signal. Images PMID:8054684

  7. Sensory Transduction in Caenorhabditis elegans

    Science.gov (United States)

    Brown, Austin L.; Ramot, Daniel; Goodman, Miriam B.

    The roundworm Caenorhabditis elegans has a well-defined and comparatively simple repertoire of sensory-guided behaviors, all of which rely on its ability to detect chemical, mechanical or thermal stimuli. In this chapter, we review what is known about the ion channels that mediate sensation in this remarkable model organism. Genetic screens for mutants defective in sensory-guided behaviors have identified genes encoding channel proteins, which are likely transducers of chemical, thermal, and mechanical stimuli. Such classical genetic approaches are now being coupled with molecular genetics and in vivo cellular physiology to elucidate how these channels are activated in specific sensory neurons. The ion channel superfamilies implicated in sensory transduction in C. elegans - CNG, TRP, and DEG/ENaC - are conserved across phyla and also appear to contribute to sensory transduction in other organisms, including vertebrates. What we learn about the role of these ion channels in C. elegans sensation is likely to illuminate analogous processes in other animals, including humans.

  8. Antimicrobial peptides in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    A Bogaerts

    2010-01-01

    Full Text Available The nematode Caenorhabditis elegans is one of the most successful model species for experimental research because of its sequenced genome, the versatile genetic toolkit and the straightforward breeding among others. In natural conditions however, this tiny worm is constantly surrounded by micro-organisms, simultaneously a source of indispensable nutrition and inevitable pathogens. Lacking an adaptive immune system, the worm solely relies on its innate immune defence to cope with its challenging life style. Hence C. elegans is an excellent model to gain more insight in innate immunity, which is remarkably preserved between invertebrate and vertebrate animals. The innate defence consists of receptors to detect potential pathogens, a complex network of signalling pathways and last but not least, effector molecules to abolish harmful microbes. In this review, we focus on the antimicrobial peptides, a vital subgroup of effector molecules. We summarise the current knowledge of the different families of C. elegans antimicrobial peptides, comprising NLPs, caenacins, ABFs, caenopores, and a recently discovered group with antifungal activity among which thaumatin-like proteins.

  9. Caenorhabditis elegans glia modulate neuronal activity and behavior

    OpenAIRE

    Randy F Stout; Alexei eVerkhratsky; Vladimir eParpura

    2014-01-01

    Glial cells of Caenorhabditis elegans can modulate neuronal activity and behavior, which is the focus of this review. Initially, we provide an overview of neuroglial evolution, making a comparison between C. elegans glia and their genealogical counterparts. What follows is a brief discussion on C. elegans glia characteristics in terms of their exact numbers, germ layers origin, their necessity for proper development of sensory organs, and lack of their need for neuronal survival. The more spe...

  10. Toxicity of Naphthalene on Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-hua; XU Jing-bo; LIU Cheng-bai; LI Qiao; GUAN Shu-wen; WANG Li-ping

    2011-01-01

    Naphthalene is a common environmental contaminant substance. The toxic effects of naphthalene on Caenorhabditis elegans were investigated at the molecular, biochemical and physiological levels. To assess the molecular-level effect, stress-related gene expression was investigated such as those of hsp-16.1, sod-3, ctl-2, cep-1,cyp35a2, ugt-44, gst-1 and dhs-28. Cell apoptosis was assessed at the biochemical level. Life span, locomotion behaviors and brood size were investigated at the physiological level. The results indicate that naphthalene exposure could not only induce the expression of stress-related genes such as hspl6.1, sod-3, ctl-2 and cep-1 but also reduce the life span of Caenorhabditis elegans. At the same time, naphthalene exposure could result in cell apoptosis and interfere in the locomotion behaviors of Caenorhabditis elegans. These data suggest that naphthalene has multiple toxicity on Caenorhabditis elegans.

  11. Microfluidic Devices in Advanced Caenorhabditis elegans Research

    Directory of Open Access Journals (Sweden)

    Muniesh Muthaiyan Shanmugam

    2016-08-01

    Full Text Available The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology.

  12. Small-molecule pheromones that control dauer development in Caenorhabditis elegans.

    Science.gov (United States)

    Butcher, Rebecca A; Fujita, Masaki; Schroeder, Frank C; Clardy, Jon

    2007-07-01

    In response to high population density or low food supply, the nematode Caenorhabditis elegans enters an alternative larval stage, known as the dauer, that can withstand adverse conditions for prolonged periods. C. elegans senses its population density through a small-molecule signal, traditionally called the dauer pheromone, that it secretes into its surroundings. Here we show that the dauer pheromone consists of several structurally related ascarosides-derivatives of the dideoxysugar ascarylose-and that two of these ascarosides (1 and 2) are roughly two orders of magnitude more potent at inducing dauer formation than a previously reported dauer pheromone component (3) and constitute a physiologically relevant signal. The identification of dauer pheromone components 1 and 2 will facilitate the identification of target receptors and downstream signaling proteins.

  13. The draft genome sequence of the nematode Caenorhabditis briggsae, a companion to C. elegans.

    Science.gov (United States)

    Gupta, Bhagwati P; Sternberg, Paul W

    2003-01-01

    The publication of the draft genome sequence of Caenorhabditis briggsae improves the annotation of the genome of its close relative Caenorhabditis elegans and will facilitate comparative genomics and the study of the evolutionary changes during development.

  14. Caenorhabditis elegans MES-3 is a target of GLD-1 and functions epigenetically in germline development.

    Science.gov (United States)

    Xu, L; Paulsen, J; Yoo, Y; Goodwin, E B; Strome, S

    2001-11-01

    The maternal-effect sterile (MES) proteins are maternally supplied regulators of germline development in Caenorhabditis elegans. In the hermaphrodite progeny from mes mutant mothers, the germline dies during larval development. On the basis of the similarities of MES-2 and MES-6 to known transcriptional regulators and on the basis of the effects of mes mutations on transgene expression in the germline, the MES proteins are predicted to be transcriptional repressors. One of the MES proteins, MES-3, is a novel protein with no recognizable motifs. In this article we show that MES-3 is localized in the nuclei of embryos and germ cells, consistent with its predicted role in transcriptional regulation. Its distribution in the germline and in early embryos does not depend on the wild-type functions of the other MES proteins. However, its nuclear localization in midstage embryos and its persistence in the primordial germ cells depend on wild-type MES-2 and MES-6. These results are consistent with biochemical data showing that MES-2, MES-3, and MES-6 associate in a complex in embryos. The distribution of MES-3 in the adult germline is regulated by the translational repressor GLD-1: MES-3 is absent from the region of the germline where GLD-1 is known to be present, MES-3 is overexpressed in the germline of gld-1 mutants, and GLD-1 specifically binds the mes-3 3' untranslated region (3' UTR). Analysis of temperature-shifted mes-3(bn21ts) worms and embryos indicates that MES-3 function is required in the mother's germline and during embryogenesis to ensure subsequent normal germline development. We propose that MES-3 acts epigenetically to induce a germline state that is inherited through both meiosis and mitosis and that is essential for survival of the germline.

  15. The Nematode Caenorhabditis Elegans.

    Science.gov (United States)

    Kenyon, Cynthia

    1988-01-01

    Discusses advantages of nematode use for studying patterns of cell division, differentiation, and morphogenesis. Describes nematode development. Cites experimental approaches available for genetic studies. Reviews the topics of control of cell division and differentiation, the nervous system, and muscle assembly and function of the organism. (RT)

  16. Complex cooperative functions of heparan sulfate proteoglycans shape nervous system development in Caenorhabditis elegans.

    Science.gov (United States)

    Díaz-Balzac, Carlos A; Lázaro-Peña, María I; Tecle, Eillen; Gomez, Nathali; Bülow, Hannes E

    2014-08-05

    The development of the nervous system is a complex process requiring the integration of numerous molecular cues to form functional circuits. Many cues are regulated by heparan sulfates, a class of linear glycosaminoglycan polysaccharides. These sugars contain distinct modification patterns that regulate protein-protein interactions. Misexpressing the homolog of KAL-1/anosmin-1, a neural cell adhesion molecule mutant in Kallmann syndrome, in Caenorhabditis elegans causes a highly penetrant, heparan sulfate-dependent axonal branching phenotype in AIY interneurons. In an extended forward genetic screen for modifiers of this phenotype, we identified alleles in new as well as previously identified genes involved in HS biosynthesis and modification, namely the xylosyltransferase sqv-6, the HS-6-O-sulfotransferase hst-6, and the HS-3-O-sulfotransferase hst-3.2. Cell-specific rescue experiments showed that different HS biosynthetic and modification enzymes can be provided cell-nonautonomously by different tissues to allow kal-1-dependent branching of AIY. In addition, we show that heparan sulfate proteoglycan core proteins that carry the heparan sulfate chains act genetically in a highly redundant fashion to mediate kal-1-dependent branching in AIY neurons. Specifically, lon-2/glypican and unc-52/perlecan act in parallel genetic pathways and display synergistic interactions with sdn-1/syndecan to mediate kal-1 function. Because all of these heparan sulfate core proteins have been shown to act in different tissues, these studies indicate that KAL-1/anosmin-1 requires heparan sulfate with distinct modification patterns of different cellular origin for function. Our results support a model in which a three-dimensional scaffold of heparan sulfate mediates KAL-1/anosmin-1 and intercellular communication through complex and cooperative interactions. In addition, the genes we have identified could contribute to the etiology of Kallmann syndrome in humans.

  17. Extended longevity and robust early-stage development of Caenorhabditis elegans by a soil microbe, Lysinibacillus sphaericus.

    Science.gov (United States)

    Go, Junhyeok; Lee, Kang-Mu; Park, Yongjin; Yoon, Sang Sun

    2014-12-01

    Caenorhabditis elegans, originally isolated from soil, is a nematode used in various fields of biological research including host–microbe interaction. While bacterial pathogens responsible for human infections have been actively studied in C. elegans, very few bacterial species that provide beneficial effects on C. elegans have been reported. Here, we tested several bacterial soil isolates and then characterized the effects of Lysinibacillus sphaericus on C. elegans growth-related phenotypes. Worms fed with L. sphaericus lived significantly longer than those growing with typical Escherichia coli OP50. Early- and juvenile-stage growth was also highly stimulated by L. sphaericus; body size at 28 h post-hatching was > 2 times larger than OP50-fed worms and L. sphaericus-fed worms moved through the larval stage development more rapidly than control worms. In addition, significantly elevated fertilization was observed in worms fed with L. sphaericus (∼ 8 h faster than the control group). Furthermore, growth with L. sphaericus resulted in the production of larger numbers of progeny than the control growth with OP50. Worms grown with L. sphaericus were highly resistant to oxidative, osmotic and infection stresses. Together, our results reveal a novel mode of growth that involves healthy ageing of nematodes.

  18. A blend of small molecules regulates both mating and development in Caenorhabditis elegans.

    Science.gov (United States)

    Srinivasan, Jagan; Kaplan, Fatma; Ajredini, Ramadan; Zachariah, Cherian; Alborn, Hans T; Teal, Peter E A; Malik, Rabia U; Edison, Arthur S; Sternberg, Paul W; Schroeder, Frank C

    2008-08-28

    In many organisms, population-density sensing and sexual attraction rely on small-molecule-based signalling systems. In the nematode Caenorhabditis elegans, population density is monitored through specific glycosides of the dideoxysugar ascarylose (the 'ascarosides') that promote entry into an alternative larval stage, the non-feeding and highly persistent dauer stage. In addition, adult C. elegans males are attracted to hermaphrodites by a previously unidentified small-molecule signal. Here we show, by means of combinatorial activity-guided fractionation of the C. elegans metabolome, that the mating signal consists of a synergistic blend of three dauer-inducing ascarosides, which we call ascr#2, ascr#3 and ascr#4. This blend of ascarosides acts as a potent male attractant at very low concentrations, whereas at the higher concentrations required for dauer formation the compounds no longer attract males and instead deter hermaphrodites. The ascarosides ascr#2 and ascr#3 carry different, but overlapping, information, as ascr#3 is more potent as a male attractant than ascr#2, whereas ascr#2 is slightly more potent than ascr#3 in promoting dauer formation. We demonstrate that ascr#2, ascr#3 and ascr#4 are strongly synergistic, and that two types of neuron, the amphid single-ciliated sensory neuron type K (ASK) and the male-specific cephalic companion neuron (CEM), are required for male attraction by ascr#3. On the basis of these results, male attraction and dauer formation in C. elegans appear as alternative behavioural responses to a common set of signalling molecules. The ascaroside signalling system thus connects reproductive and developmental pathways and represents a unique example of structure- and concentration-dependent differential activity of signalling molecules.

  19. Lipocalin signaling controls unicellular tube development in the Caenorhabditis elegans excretory system.

    Science.gov (United States)

    Stone, Craig E; Hall, David H; Sundaram, Meera V

    2009-05-15

    Unicellular tubes or capillaries composed of individual cells with a hollow lumen perform important physiological functions including fluid or gas transport and exchange. These tubes are thought to build intracellular lumina by polarized trafficking of apical membrane components, but the molecular signals that promote luminal growth and luminal connectivity between cells are poorly understood. Here we show that the lipocalin LPR-1 is required for luminal connectivity between two unicellular tubes in the Caenorhabditis elegans excretory (renal) system, the excretory duct cell and pore cell. Lipocalins are a large family of secreted proteins that transport lipophilic cargos and participate in intercellular signaling. lpr-1 is required at a time of rapid luminal growth, it is expressed by the duct, pore and surrounding cells, and it can function cell non-autonomously. These results reveal a novel signaling mechanism that controls unicellular tube formation, and provide a genetic model system for dissecting lipocalin signaling pathways.

  20. Optogenetic mutagenesis in Caenorhabditis elegans

    Science.gov (United States)

    Noma, Kentaro; Jin, Yishi

    2015-01-01

    Reactive oxygen species (ROS) can modify and damage DNA. Here we report an optogenetic mutagenesis approach that is free of toxic chemicals and easy to perform by taking advantage of a genetically encoded ROS generator. This method relies on the potency of ROS generation by His-mSOG, the mini singlet oxygen generator, miniSOG, fused to a histone. Caenorhabditis elegans expressing His-mSOG in the germline behave and reproduce normally, without photoinduction. Following exposure to blue light, the His-mSOG animals produce progeny with a wide range of heritable phenotypes. We show that optogenetic mutagenesis by His-mSOG induces a broad spectrum of mutations including single-nucleotide variants (SNVs), chromosomal deletions, as well as integration of extrachromosomal transgenes, which complements those derived from traditional chemical or radiation mutagenesis. The optogenetic mutagenesis expands the toolbox for forward genetic screening and also provides direct evidence that nuclear ROS can induce heritable and specific genetic mutations. PMID:26632265

  1. Caenorhabditis elegans vulval cell fate patterning

    Science.gov (United States)

    Félix, Marie-Anne

    2012-08-01

    The spatial patterning of three cell fates in a row of competent cells is exemplified by vulva development in the nematode Caenorhabditis elegans. The intercellular signaling network that underlies fate specification is well understood, yet quantitative aspects remain to be elucidated. Quantitative models of the network allow us to test the effect of parameter variation on the cell fate pattern output. Among the parameter sets that allow us to reach the wild-type pattern, two general developmental patterning mechanisms of the three fates can be found: sequential inductions and morphogen-based induction, the former being more robust to parameter variation. Experimentally, the vulval cell fate pattern is robust to stochastic and environmental challenges, and minor variants can be detected. The exception is the fate of the anterior cell, P3.p, which is sensitive to stochastic variation and spontaneous mutation, and is also evolving the fastest. Other vulval precursor cell fates can be affected by mutation, yet little natural variation can be found, suggesting stabilizing selection. Despite this fate pattern conservation, different Caenorhabditis species respond differently to perturbations of the system. In the quantitative models, different parameter sets can reconstitute their response to perturbation, suggesting that network variation among Caenorhabditis species may be quantitative. Network rewiring likely occurred at longer evolutionary scales.

  2. Targeted genome engineering in Caenorhabditis elegans.

    Science.gov (United States)

    Chen, Xiangyang; Feng, Xuezhu; Guang, Shouhong

    2016-01-01

    The generation of mutants and transgenes are indispensible for biomedical research. In the nematode Caenorhabditis elegans, a series of methods have been developed to introduce genome modifications, including random mutagenesis by chemical reagents, ionizing radiation and transposon insertion. In addition, foreign DNA can be integrated into the genome through microparticle bombardment approach or by irradiation of animals carrying microinjected extrachromosomal arrays. Recent research has revolutionized the genome engineering technologies by using customized DNA nucleases to manipulate particular genes and genomic sequences. Many streamlined editing strategies are developed to simplify the experimental procedure and minimize the cost. In this review, we will summarize the recent progress of the site-specific genome editing methods in C. elegans, including the Cre/LoxP, FLP/FRT, MosTIC system, zinc-finger nucleases (ZFNs), transcriptional activator-like nucleases (TALENs), and the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 nuclease. Particularly, the recent studies of CRISPR/Cas9-mediated genome editing method in C. elegans will be emphatically discussed.

  3. Building a cell and anatomy ontology of Caenorhabditis elegans.

    Science.gov (United States)

    Lee, Raymond Y N; Sternberg, Paul W

    2003-01-01

    We are endowed with a rich knowledge about Caenorhabditis elegans. Its stereotyped anatomy and development has stimulated research and resulted in the accumulation of cell-based information concerning gene expression, and the role of specific cells in developmental signalling and behavioural circuits. To make the information more accessible to sophisticated queries and automated retrieval systems, WormBase has begun to construct a C. elegans cell and anatomy ontology. Here we present our strategies and progress.

  4. Control of Neuronal Network in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Rahul Badhwar

    Full Text Available Caenorhabditis elegans, a soil dwelling nematode, is evolutionarily rudimentary and contains only ∼ 300 neurons which are connected to each other via chemical synapses and gap junctions. This structural connectivity can be perceived as nodes and edges of a graph. Controlling complex networked systems (such as nervous system has been an area of excitement for mankind. Various methods have been developed to identify specific brain regions, which when controlled by external input can lead to achievement of control over the state of the system. But in case of neuronal connectivity network the properties of neurons identified as driver nodes is of much importance because nervous system can produce a variety of states (behaviour of the animal. Hence to gain insight on the type of control achieved in nervous system we implemented the notion of structural control from graph theory to C. elegans neuronal network. We identified 'driver neurons' which can provide full control over the network. We studied phenotypic properties of these neurons which are referred to as 'phenoframe' as well as the 'genoframe' which represents their genetic correlates. We find that the driver neurons are primarily motor neurons located in the ventral nerve cord and contribute to biological reproduction of the animal. Identification of driver neurons and its characterization adds a new dimension in controllability of C. elegans neuronal network. This study suggests the importance of driver neurons and their utility to control the behaviour of the organism.

  5. Acute carbon dioxide avoidance in Caenorhabditis elegans

    OpenAIRE

    Hallem, Elissa A.; Sternberg, Paul W.

    2008-01-01

    Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement....

  6. 线虫发育模式的阐述及相关思考%The Studies and Further Discussion of Development Model in Caenorhabditis Elegans

    Institute of Scientific and Technical Information of China (English)

    刘云啸

    2013-01-01

    Caenorhabditis elegans is an important model organism for its limited cell numbers and stable cell lineagc in development. In this paper, the reasons why Caenorhabditis elegans is highly utilized in genetic analysis and some further discussions will be elucidated according to the development model in Caenorhabditis elegans.%目前,在发育生物学研究中,线虫(Caenorhabditis elegans)是一种主要的模式动物,其发育细胞数目少且细胞谱系恒定。在这里,本文作者希望通过对线虫发育模式的了解和探究来大致阐述线虫适于进行遗传分析的原因及相关的思考与启发。目前,在发育生物学研究中,线虫(Caenorhabditis elegans)是一种主要的模式动物,其发育细胞数目少且细胞谱系恒定。在这里,本文作者希望通过对线虫发育模式的了解和探究来大致阐述线虫适于进行遗传分析的原因及相关的思考与启发。

  7. Rictor/TORC2 regulates Caenorhabditis elegans fat storage, body size, and development through sgk-1.

    Directory of Open Access Journals (Sweden)

    Kevin T Jones

    2009-03-01

    Full Text Available The target of rapamycin (TOR kinase coordinately regulates fundamental metabolic and cellular processes to support growth, proliferation, survival, and differentiation, and consequently it has been proposed as a therapeutic target for the treatment of cancer, metabolic disease, and aging. The TOR kinase is found in two biochemically and functionally distinct complexes, termed TORC1 and TORC2. Aided by the compound rapamycin, which specifically inhibits TORC1, the role of TORC1 in regulating translation and cellular growth has been extensively studied. The physiological roles of TORC2 have remained largely elusive due to the lack of pharmacological inhibitors and its genetic lethality in mammals. Among potential targets of TORC2, the pro-survival kinase AKT has garnered much attention. Within the context of intact animals, however, the physiological consequences of phosphorylation of AKT by TORC2 remain poorly understood. Here we describe viable loss-of-function mutants in the Caenorhabditis elegans homolog of the TORC2-specific component, Rictor (CeRictor. These mutants display a mild developmental delay and decreased body size, but have increased lipid storage. These functions of CeRictor are not mediated through the regulation of AKT kinases or their major downstream target, the insulin-regulated FOXO transcription factor DAF-16. We found that loss of sgk-1, a homolog of the serum- and glucocorticoid-induced kinase, mimics the developmental, growth, and metabolic phenotypes of CeRictor mutants, while a novel, gain-of-function mutation in sgk-1 suppresses these phenotypes, indicating that SGK-1 is a mediator of CeRictor activity. These findings identify new physiological roles for TORC2, mediated by SGK, in regulation of C. elegans lipid accumulation and growth, and they challenge the notion that AKT is the primary effector of TORC2 function.

  8. Functional dissection of Caenorhabditis elegans CLK-2/TEL2 cell cycle defects during embryogenesis and germline development.

    Directory of Open Access Journals (Sweden)

    Sandra C Moser

    2009-04-01

    Full Text Available CLK-2/TEL2 is essential for viability from yeasts to vertebrates, but its essential functions remain ill defined. CLK-2/TEL2 was initially implicated in telomere length regulation in budding yeast, but work in Caenorhabditis elegans has uncovered a function in DNA damage response signalling. Subsequently, DNA damage signalling defects associated with CLK-2/TEL2 have been confirmed in yeast and human cells. The CLK-2/TEL2 interaction with the ATM and ATR DNA damage sensor kinases and its requirement for their stability led to the proposal that CLK-2/TEL2 mutants might phenocopy ATM and/or ATR depletion. We use C. elegans to dissect developmental and cell cycle related roles of CLK-2. Temperature sensitive (ts clk-2 mutants accumulate genomic instability and show a delay of embryonic cell cycle timing. This delay partially depends on the worm p53 homolog CEP-1 and is rescued by co-depletion of the DNA replication checkpoint proteins ATL-1 (C. elegans ATR and CHK-1. In addition, clk-2 ts mutants show a spindle orientation defect in the eight cell stages that lead to major cell fate transitions. clk-2 deletion worms progress through embryogenesis and larval development by maternal rescue but become sterile and halt germ cell cycle progression. Unlike ATL-1 depleted germ cells, clk-2-null germ cells do not accumulate DNA double-strand breaks. Rather, clk-2 mutant germ cells arrest with duplicated centrosomes but without mitotic spindles in an early prophase like stage. This germ cell cycle arrest does not depend on cep-1, the DNA replication, or the spindle checkpoint. Our analysis shows that CLK-2 depletion does not phenocopy PIKK kinase depletion. Rather, we implicate CLK-2 in multiple developmental and cell cycle related processes and show that CLK-2 and ATR have antagonising functions during early C. elegans embryonic development.

  9. Caenorhabditis elegans response to salt

    NARCIS (Netherlands)

    O.O. Umuerri (Oluwatoroti Omowayewa)

    2012-01-01

    textabstractThis thesis describes my work, where I used genetic methods to identify new genes involved in salt taste in C. elegans. In addition, I used calcium imaging to characterize the cellular response of C. elegans to salt. The thesis is divided into five sections and each section is summarized

  10. Development of a method to quantitate nematode pheromone for study of small-molecule metabolism in Caenorhabditis elegans.

    Science.gov (United States)

    Kim, Kwang-Youl; Joo, Hyoe-Jin; Kwon, Hye-Won; Kim, Heekyeong; Hancock, William S; Paik, Young-Ki

    2013-03-05

    Pheromones produced by Caenorhabditis elegans are considered key regulators of development, mating, and social behaviors in this organism. Here, we present a rapid mass spectrometry-based method (PheroQu) for absolute quantitation of nematode pheromones (e.g., daumone 1, 2, and 3) both in C. elegans worm bodies (as few as 20 worms) and in liquid culture medium. Pheromones were separated by ultra performance liquid chromatography and monitored by a positive electrospray ionization detector in the multiple-reaction monitoring mode. The daf-22 mutant worms were used as surrogate matrix for calibration, and stable deuterated isotope-containing pheromone was used as internal standard for measuring changes in pheromones in N2 wild-type and other strains under different growth conditions. The worm-body pheromones were extracted by acidified acetonitrile solvent, and the secreted pheromones were extracted from culture medium with solid-phase extraction cartridges. The run time was achieved in less than 2 min. The method was validated for specificity, linearity, accuracy, precision, recovery, and stability. The assay was linear over an amount range of 2-250 fmol, and the limit of quantitation was 2 fmol amounts for daumone 1, 2, and 3 in both worm bodies and culture medium. With the PheroQu method, we were able to identify the location of pheromone biosynthesis and determine the changes in different pheromone types synthesized, according to developmental stages and aging process. This method, which is simple, rapid, sensitive, and specific, will be useful for the study of small-molecule metabolism during developmental stages of C. elegans.

  11. Biosynthesis of the Caenorhabditis elegans dauer pheromone

    OpenAIRE

    Butcher, Rebecca A.; Ragains, Justin R.; Li, Weiqing; RUVKUN, GARY; Clardy, Jon; Mak, Ho Yi

    2009-01-01

    To sense its population density and to trigger entry into the stress-resistant dauer larval stage, Caenorhabditis elegans uses the dauer pheromone, which consists of ascaroside derivatives with short, fatty acid-like side chains. Although the dauer pheromone has been studied for 25 years, its biosynthesis is completely uncharacterized. The daf-22 mutant is the only known mutant defective in dauer pheromone production. Here, we show that daf-22 encodes a homolog of human sterol carrier protein...

  12. Mainstreaming Caenorhabditis elegans in experimental evolution.

    Science.gov (United States)

    Gray, Jeremy C; Cutter, Asher D

    2014-03-01

    Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.

  13. Dietary restriction during development enlarges intestinal and hypodermal lipid droplets in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Daniela Palgunow

    Full Text Available Dietary restriction (DR extends lifespan in man species and modulates evolutionary conserved signalling and metabolic pathways. Most of these studies were done in adult animals. Here we investigated fat phenotypes of C. elegans larvae and adults which were exposed to DR during development. This approach was named "developmental-DR" (dDR. Moderate as well as stringent dDR increased the triglyceride to protein ratio in L4 larvae and adult worms. This alteration was accompanied by a marked expansion of intestinal and hypodermal lipid droplets. In comparison to ad libitum condition, the relative proportion of fat stored in large lipid droplets (>50 µm(3 was increased by a factor of about 5 to 6 in larvae exposed to dDR. Microarray-based expression profiling identified several dDR-regulated genes of lipolysis and lipogenesis which may contribute to the observed fat phenotypes. In conclusion, dDR increases the triglyceride to protein ratio, enlarges lipid droplets and alters the expression of genes functioning in lipid metabolism in C. elegans. These changes might be an effective adaptation to conserve fat stores in animals subjected to limiting food supply during development.

  14. Regulation of Caenorhabditis elegans body size and male tail development by the novel gene lon-8

    Directory of Open Access Journals (Sweden)

    Korswagen Hendrik C

    2007-03-01

    Full Text Available Abstract Background In C. elegans and other nematode species, body size is determined by the composition of the extracellular cuticle as well as by the nuclear DNA content of the underlying hypodermis. Mutants that are defective in these processes can exhibit either a short or a long body size phenotype. Several mutations that give a long body size (Lon phenotype have been characterized and found to be regulated by the DBL-1/TGF-β pathway, that controls post-embryonic growth and male tail development. Results Here we characterize a novel gene affecting body size. lon-8 encodes a secreted product of the hypodermis that is highly conserved in Rhabditid nematodes. lon-8 regulates larval elongation as well as male tail development. In both processes, lon-8 appears to function independently of the Sma/Mab pathway. Rather, lon-8 genetically interacts with dpy-11 and dpy-18, which encode cuticle collagen modifying enzymes. Conclusion The novel gene lon-8 encodes a secreted product of the hypodermis that controls body size and male ray morphology in C. elegans. lon-8 genetically interacts with enzymes that affect the composition of the cuticle.

  15. Phospholipase Cepsilon regulates ovulation in Caenorhabditis elegans.

    Science.gov (United States)

    Kariya, Ken-Ichi; Bui, Yen Kim; Gao, Xianlong; Sternberg, Paul W; Kataoka, Tohru

    2004-10-01

    Phospholipase Cepsilon (PLCepsilon) is a novel class of phosphoinositide-specific PLC with unknown physiological functions. Here, we present the first genetic analysis of PLCepsilon in an intact organism, the nematode Caenorhabditis elegans. Ovulation in C. elegans is dependent on an inositol 1,4,5-trisphosphate (IP(3)) signaling pathway activated by the receptor tyrosine kinase LET-23. We generated deletion mutants of the gene, plc-1, encoding C. elegans PLCepsilon. We observed a novel ovulation phenotype whereby oocytes are trapped in the spermatheca due to delayed dilation of the spermatheca-uterine valve. The expression of plc-1 in the adult spermatheca is consistent with its involvement in regulation of ovulation. On the other hand, we failed to observe genetic interaction of plc-1 with let-23-mediated IP(3) signaling pathway genes, suggesting a complex mechanism for control of ovulation.

  16. Collaborative regulation of development but independent control of metabolism by two epidermis-specific transcription factors in Caenorhabditis elegans.

    Science.gov (United States)

    Shao, Jiaofang; He, Kan; Wang, Hao; Ho, Wing Sze; Ren, Xiaoliang; An, Xiaomeng; Wong, Ming Kin; Yan, Bin; Xie, Dongying; Stamatoyannopoulos, John; Zhao, Zhongying

    2013-11-15

    Cell fate specification is typically initiated by a master regulator, which is relayed by tissue-specific regulatory proteins (usually transcription factors) for further enforcement of cell identities, but how the factors are coordinated among each other to "finish up" the specification remains poorly understood. Caenorhabditis elegans epidermis specification is initiated by a master regulator, ELT-1, that activates its targets, NHR-25 and ELT-3, two epidermis-specific transcription factors that are important for development but not for initial specification of epidermis, thus providing a unique paradigm for illustrating how the tissue-specific regulatory proteins work together to enforce cell fate specification. Here we addressed the question through contrasting genome-wide in vivo binding targets between NHR-25 and ELT-3. We demonstrate that the two factors bind discrete but conserved DNA motifs, most of which remain in proximity, suggesting formation of a complex between the two. In agreement with this, gene ontology analysis of putative target genes suggested differential regulation of metabolism but coordinated control of epidermal development between the two factors, which is supported by quantitative analysis of expression of their specific or common targets in the presence or absence of either protein. Functional validation of a subset of the target genes showed both activating and inhibitory roles of NHR-25 and ELT-3 in regulating their targets. We further demonstrated differential control of specification of AB and C lineage-derived epidermis. The results allow us to assemble a comprehensive gene network underlying C. elegans epidermis development that is likely to be widely used across species and provides insights into how tissue-specific transcription factors coordinate with one another to enforce cell fate specification initiated by its master regulator.

  17. Effects of sub-lethal teratogen exposure during larval development on egg laying and egg quality in adult Caenorhabditis elegans

    Science.gov (United States)

    Killeen, Alexis; Marin de Evsikova, Caralina

    2016-01-01

    Background: Acute high dose exposure to teratogenic chemicals alters the proper development of an embryo leading to infertility, impaired fecundity, and few viable offspring. However, chronic exposure to sub-toxic doses of teratogens during early development may also have long-term impacts on egg quality and embryo viability. Methods: To test the hypothesis that low dose exposure during early development can impact long-term reproductive health, Caenorhabditis elegans larvae were exposed to 10 teratogens during larval development, and subsequently were examined for the pattern of egg-laying and egg quality (hatched larvae and embryo viability) as gravid adults.  After the exposure, adult gravid worms were transferred to untreated plates and the numbers of eggs laid were recorded every 3 hours, and the day following exposure the numbers of hatched larvae were counted. Re sults: While fecundity and fertility were typically impaired by teratogens, unexpectedly, many teratogens initially increased egg-laying at the earliest interval compared to control but not at later intervals. However, egg quality, as assessed by embryo viability, remained the same because many of the eggs (teratogens during early larval development have subtle, long-term effects on egg laying and egg quality. PMID:28163903

  18. Gustatory Behaviour in Caenorhabditis elegans

    NARCIS (Netherlands)

    R.K. Hukema (Renate)

    2006-01-01

    textabstractThe nematode C. elegans is an ideal model-organism to study the genetics of behaviour (Brenner, 1974). It is capable of sensing salts and we discriminate three different responses: it is attracted to low salt concentrations (Ward, 1973; Dusenbery et al., 1974), it avoids high salt concen

  19. Big Data in Caenorhabditis elegans: quo vadis?

    Science.gov (United States)

    Hutter, Harald; Moerman, Donald

    2015-11-05

    A clear definition of what constitutes "Big Data" is difficult to identify, but we find it most useful to define Big Data as a data collection that is complete. By this criterion, researchers on Caenorhabditis elegans have a long history of collecting Big Data, since the organism was selected with the idea of obtaining a complete biological description and understanding of development. The complete wiring diagram of the nervous system, the complete cell lineage, and the complete genome sequence provide a framework to phrase and test hypotheses. Given this history, it might be surprising that the number of "complete" data sets for this organism is actually rather small--not because of lack of effort, but because most types of biological experiments are not currently amenable to complete large-scale data collection. Many are also not inherently limited, so that it becomes difficult to even define completeness. At present, we only have partial data on mutated genes and their phenotypes, gene expression, and protein-protein interaction--important data for many biological questions. Big Data can point toward unexpected correlations, and these unexpected correlations can lead to novel investigations; however, Big Data cannot establish causation. As a result, there is much excitement about Big Data, but there is also a discussion on just what Big Data contributes to solving a biological problem. Because of its relative simplicity, C. elegans is an ideal test bed to explore this issue and at the same time determine what is necessary to build a multicellular organism from a single cell.

  20. Student Learning of Early Embryonic Development via the Utilization of Research Resources from the Nematode Caenorhabditis elegans

    Science.gov (United States)

    Eliceiri, Kevin W.; Squirrell, Jayne M.; White, John G.; Stewart, James

    2008-01-01

    This study was undertaken to gain insights into undergraduate students' understanding of early embryonic development, specifically, how well they comprehend the concepts of volume constancy, cell lineages, body plan axes, and temporal and spatial dimensionality in development. To study student learning, a curriculum was developed incorporating resources from the Caenorhabditis elegans research community. Students engaged in a preactivity assessment, followed by instructional materials (IMs) emphasizing inquiry-based learning and a postinstruction assessment to gauge their learning. This study, conducted at two research sites with eight and nine students, respectively, shows that before instruction, most students confused embryonic cell cleavage, where total volume is constant, with regular cell division, in which total cell volume doubles. Despite their ability to construct a cell lineage tree, most of the study participants were not aware of its biological significance. All students correctly identified cells of anterior and posterior axis, but not cells of the dorsal and ventral axis. Although the students had no difficulty with the time dimensional aspect of development, most viewed an embryo as spatially two-dimensional rather than three-dimensional. Furthermore, this study indicates that combining authentic research resources with inquiry-based learning benefits student learning of key concepts in embryology. PMID:18316809

  1. Combinatorial roles of heparan sulfate proteoglycans and heparan sulfates in Caenorhabditis elegans neural development.

    Directory of Open Access Journals (Sweden)

    Tarja K Kinnunen

    Full Text Available Heparan sulfate proteoglycans (HSPGs play critical roles in the development and adult physiology of all metazoan organisms. Most of the known molecular interactions of HSPGs are attributed to the structurally highly complex heparan sulfate (HS glycans. However, whether a specific HSPG (such as syndecan contains HS modifications that differ from another HSPG (such as glypican has remained largely unresolved. Here, a neural model in C. elegans is used to demonstrate for the first time the relationship between specific HSPGs and HS modifications in a defined biological process in vivo. HSPGs are critical for the migration of hermaphrodite specific neurons (HSNs as genetic elimination of multiple HSPGs leads to 80% defect of HSN migration. The effects of genetic elimination of HSPGs are additive, suggesting that multiple HSPGs, present in the migrating neuron and in the matrix, act in parallel to support neuron migration. Genetic analyses suggest that syndecan/sdn-1 and HS 6-O-sulfotransferase, hst-6, function in a linear signaling pathway and glypican/lon-2 and HS 2-O-sulfotransferase, hst-2, function together in a pathway that is parallel to sdn-1 and hst-6. These results suggest core protein specific HS modifications that are critical for HSN migration. In C. elegans, the core protein specificity of distinct HS modifications may be in part regulated at the level of tissue specific expression of genes encoding for HSPGs and HS modifying enzymes. Genetic analysis reveals that there is a delicate balance of HS modifications and eliminating one HS modifying enzyme in a compromised genetic background leads to significant changes in the overall phenotype. These findings are of importance with the view of HS as a critical regulator of cell signaling in normal development and disease.

  2. Regulation of Axonal Midline Guidance by Prolyl 4-Hydroxylation in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Torpe, Nanna; Pocock, Roger David John

    2014-01-01

    Neuronal wiring during development requires that the growth cones of axons and dendrites are correctly guided to their appropriate targets. As in other animals, axon growth cones in Caenorhabditis elegans integrate information in their extracellular environment via interactions among transiently...

  3. daf-31 encodes the catalytic subunit of N alpha-acetyltransferase that regulates Caenorhabditis elegans development, metabolism and adult lifespan.

    Science.gov (United States)

    Chen, Di; Zhang, Jiuli; Minnerly, Justin; Kaul, Tiffany; Riddle, Donald L; Jia, Kailiang

    2014-10-01

    The Caenorhabditis elegans dauer larva is a facultative state of diapause. Mutations affecting dauer signal transduction and morphogenesis have been reported. Of these, most that result in constitutive formation of dauer larvae are temperature-sensitive (ts). The daf-31 mutant was isolated in genetic screens looking for novel and underrepresented classes of mutants that form dauer and dauer-like larvae non-conditionally. Dauer-like larvae are arrested in development and have some, but not all, of the normal dauer characteristics. We show here that daf-31 mutants form dauer-like larvae under starvation conditions but are sensitive to SDS treatment. Moreover, metabolism is shifted to fat accumulation in daf-31 mutants. We cloned the daf-31 gene and it encodes an ortholog of the arrest-defective-1 protein (ARD1) that is the catalytic subunit of the major N alpha-acetyltransferase (NatA). A daf-31 promoter::GFP reporter gene indicates daf-31 is expressed in multiple tissues including neurons, pharynx, intestine and hypodermal cells. Interestingly, overexpression of daf-31 enhances the longevity phenotype of daf-2 mutants, which is dependent on the forkhead transcription factor (FOXO) DAF-16. We demonstrate that overexpression of daf-31 stimulates the transcriptional activity of DAF-16 without influencing its subcellular localization. These data reveal an essential role of NatA in controlling C. elegans life history and also a novel interaction between ARD1 and FOXO transcription factors, which may contribute to understanding the function of ARD1 in mammals.

  4. The Role Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting Edge Analytical Chemistry

    Directory of Open Access Journals (Sweden)

    Hugo eAguilaniu

    2016-02-01

    Full Text Available Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches such as comprehensive and highly selective liquid chromatography coupled to mass spectrometry (LC-MS based or new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS if we are to obtain a better understanding of the biological functions of steroid signaling.

  5. Chromosome I duplications in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    McKim, K.S.; Rose, A.M. (Univ. of British Columbia, Vancouver (Canada))

    1990-01-01

    We have isolated and characterized 76 duplications of chromosome I in the genome of Caenorhabditis elegans. The region studied is the 20 map unit left half of the chromosome. Sixty-two duplications were induced with gamma radiation and 14 arose spontaneously. The latter class was apparently the result of spontaneous breaks within the parental duplication. The majority of duplications behave as if they are free. Three duplications are attached to identifiable sequences from other chromosomes. The duplication breakpoints have been mapped by complementation analysis relative to genes on chromosome I. Nineteen duplication breakpoints and seven deficiency breakpoints divide the left half of the chromosome into 24 regions. We have studied the relationship between duplication size and segregational stability. While size is an important determinant of mitotic stability, it is not the only one. We observed clear exceptions to a size-stability correlation. In addition to size, duplication stability may be influenced by specific sequences or chromosome structure. The majority of the duplications were stable enough to be powerful tools for gene mapping. Therefore the duplications described here will be useful in the genetic characterization of chromosome I and the techniques we have developed can be adapted to other regions of the genome.

  6. Biosynthesis of the Caenorhabditis elegans dauer pheromone.

    Science.gov (United States)

    Butcher, Rebecca A; Ragains, Justin R; Li, Weiqing; Ruvkun, Gary; Clardy, Jon; Mak, Ho Yi

    2009-02-10

    To sense its population density and to trigger entry into the stress-resistant dauer larval stage, Caenorhabditis elegans uses the dauer pheromone, which consists of ascaroside derivatives with short, fatty acid-like side chains. Although the dauer pheromone has been studied for 25 years, its biosynthesis is completely uncharacterized. The daf-22 mutant is the only known mutant defective in dauer pheromone production. Here, we show that daf-22 encodes a homolog of human sterol carrier protein SCPx, which catalyzes the final step in peroxisomal fatty acid beta-oxidation. We also show that dhs-28, which encodes a homolog of the human d-bifunctional protein that acts just upstream of SCPx, is also required for pheromone production. Long-term daf-22 and dhs-28 cultures develop dauer-inducing activity by accumulating less active, long-chain fatty acid ascaroside derivatives. Thus, daf-22 and dhs-28 are required for the biosynthesis of the short-chain fatty acid-derived side chains of the dauer pheromone and link dauer pheromone production to metabolic state.

  7. Reduction of mitoferrin results in abnormal development and extended lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Ren, Yaguang; Yang, Su; Tan, Guoqiang; Ye, Wei; Liu, Danhui; Qian, Xu; Ding, Zhongying; Zhong, Yuhong; Zhang, Jingrui; Jiang, Dandan; Zhao, Yuhong; Lu, Jianxin

    2012-01-01

    Iron is essential for organisms. It is mainly utilized in mitochondria for biosynthesis of iron-sulfur clusters, hemes and other cofactors. Mitoferrin 1 and mitoferrin 2, two homologues proteins belonging to the mitochondrial solute carrier family, are required for iron delivery into mitochondria. Mitoferrin 1 is highly expressed in developing erythrocytes which consume a large amount of iron during hemoglobinization. Mitoferrin 2 is ubiquitously expressed, whose functions are less known. Zebrafish with mitoferrin 1 mutation show profound hypochromic anaemia and erythroid maturation arrests, and yeast with defects in MRS3/4, the counterparts of mitoferrin 1/2, has low mitochondrial iron levels and grows poorly by iron depletion. Mitoferrin 1 expression is up-regulated in yeast and mouse models of Fiedreich's ataxia disease and in human cell culture models of Parkinson disease, suggesting its involvement in the pathogenesis of diseases with mitochondrial iron accumulation. In this study we found that reduced mitoferrin levels in C. elegans by RNAi treatment causes pleiotropic phenotypes such as small body size, reduced fecundity, slow movement and increased sensitivity to paraquat. Despite these abnormities, lifespan was increased by 50% to 80% in N2 wild type strain, and in further studies using the RNAi sensitive strain eri-1, more than doubled lifespan was observed. The pathways or mechanisms responsible for the lifespan extension and other phenotypes of mitoferrin RNAi worms are worth further study, which may contribute to our understanding of aging mechanisms and the pathogenesis of iron disorder related diseases.

  8. The invertebrate Caenorhabditis elegans biosynthesizes ascorbate.

    Science.gov (United States)

    Patananan, Alexander N; Budenholzer, Lauren M; Pedraza, Maria E; Torres, Eric R; Adler, Lital N; Clarke, Steven G

    2015-03-01

    l-Ascorbate, commonly known as vitamin C, serves as an antioxidant and cofactor essential for many biological processes. Distinct ascorbate biosynthetic pathways have been established for animals and plants, but little is known about the presence or synthesis of this molecule in invertebrate species. We have investigated ascorbate metabolism in the nematode Caenorhabditis elegans, where this molecule would be expected to play roles in oxidative stress resistance and as cofactor in collagen and neurotransmitter synthesis. Using high-performance liquid chromatography and gas-chromatography mass spectrometry, we determined that ascorbate is present at low amounts in the egg stage, L1 larvae, and mixed animal populations, with the egg stage containing the highest concentrations. Incubating C. elegans with precursor molecules necessary for ascorbate synthesis in plants and animals did not significantly alter ascorbate levels. Furthermore, bioinformatic analyses did not support the presence in C. elegans of either the plant or the animal biosynthetic pathway. However, we observed the complete (13)C-labeling of ascorbate when C. elegans was grown with (13)C-labeled Escherichia coli as a food source. These results support the hypothesis that ascorbate biosynthesis in invertebrates may proceed by a novel pathway and lay the foundation for a broader understanding of its biological role.

  9. Deficiency of the Caenorhabditis elegans DNA polymerase eta homologue increases sensitivity to UV radiation during germ-line development.

    Science.gov (United States)

    Ohkumo, Tsuyoshi; Masutani, Chikahide; Eki, Toshihiko; Hanaoka, Fumio

    2006-01-01

    Defects in the human XPV/POLH gene result in the variant form of the disease xeroderma pigmentosum (XP-V). The gene encodes DNA polymerase eta (Poleta), which catalyzes translesion synthesis (TLS) past UV-induced cyclobutane pyrimidine dimers (CPDs) and other lesions. To further understand the roles of Poleta in multicellular organisms, we analyzed phenotypes caused by suppression of Caenorhabditis elegans POLH (Ce-POLH) by RNA interference (RNAi). F1 and F2 progeny from worms treated by Ce-POLH-specific RNAi grew normally, but F1 eggs laid by worms treated by RNAi against Ce-POLD, which encodes Poldelta did not hatch. These results suggest that Poldelta but not Poleta is essential for C. elegans embryogenesis. Poleta-targeted embryos UV-irradiated after egg laying were only moderately sensitive. In contrast, Poleta-targeted embryos UV-irradiated prior to egg laying exhibited severe sensitivity, indicating that Poleta contributes significantly to damage tolerance in C. elegans in early embryogenesis but only modestly at later stages. As early embryogenesis is characterized by high levels of DNA replication, Poleta may confer UV resistance in C. elegans, perhaps by catalyzing TLS in early embryogenesis.

  10. Developing a rapid throughput screen for detection of nematicidal activity of plant cysteine proteinases: the role of Caenorhabditis elegans cystatins.

    Science.gov (United States)

    Phiri, A M; De Pomerai, D; Buttle, D J; Behnke, J M B

    2014-02-01

    Plant cysteine proteinases (CPs) from papaya (Carica papaya) are capable of killing parasitic nematode worms in vitro and have been shown to possess anthelmintic effects in vivo. The acute damage reported in gastrointestinal parasites has not been found in free-living nematodes such as Caenorhabditis elegans nor among the free-living stages of parasitic nematodes. This apparent difference in susceptibility might be the result of active production of cysteine proteinase inhibitors (such as cystatins) by the free-living stages or species. To test this possibility, a supernatant extract of refined papaya latex (PLS) with known active enzyme content was used. The effect on wild-type (Bristol N2) and cystatin null mutant (cpi-1(-/-) and cpi-2(-/-)) C. elegans was concentration-, temperature- and time-dependent. Cysteine proteinases digested the worm cuticle leading to release of internal structures and consequent death. Both cystatin null mutant strains were highly susceptible to PLS attack irrespective of the temperature and concentration of exposure, whereas wild-type N2 worms were generally resistant but far more susceptible to attack at low temperatures. PLS was able to induce elevated cpi-1 and cpi-2 cystatin expression. We conclude that wild-type C. elegans deploy cystatins CPI-1 and CPI-2 to resist CP attack. The results suggest that the cpi-1 or cpi-2 null mutants (or a double mutant combination of the two) could provide a cheap and effective rapid throughput C. elegans-based assay for screening plant CP extracts for anthelmintic activity.

  11. Aversive Olfactory Learning and Associative Long-Term Memory in "Caenorhabditis elegans"

    Science.gov (United States)

    Amano, Hisayuki; Maruyama, Ichiro N.

    2011-01-01

    The nematode "Caenorhabditis elegans" ("C. elegans") adult hermaphrodite has 302 invariant neurons and is suited for cellular and molecular studies on complex behaviors including learning and memory. Here, we have developed protocols for classical conditioning of worms with 1-propanol, as a conditioned stimulus (CS), and hydrochloride (HCl) (pH…

  12. Neuronal regulation of ascaroside response during mate response behavior in the nematode Caenorhabditis elegans

    Science.gov (United States)

    Small-molecule signaling plays an important role in the biology of Caenorhabditis elegans. We have previously shown that ascarosides, glycosides of the dideoxysugar ascarylose regulate both development and behavior in C. elegans The mating signal consists of a synergistic blend of three dauer-induc...

  13. Caenorhabditis elegans cog-1 locus encodes GTX/Nkx6.1 homeodomain proteins and regulates multiple aspects of reproductive system development.

    Science.gov (United States)

    Palmer, Robert E; Inoue, Takao; Sherwood, David R; Jiang, Lily I; Sternberg, Paul W

    2002-12-15

    The development of the reproductive system in Caenorhabditis elegans is a well-established model system for patterning and organogenesis. We report the characterization of the cog-1 gene, mutations in which cause novel phenotypes in late patterning in vulval lineages, establishment of the vulva-uterine connection, development and function of the spermathecal-uterine junction, and the development of vas deferens-proctodeal connection in the male. We positionally cloned cog-1 and found that it encodes a homeobox protein most similar to the mammalian GTX and Nkx6.1 proteins. Analysis of cog-1 transcripts revealed that cog-1 is likely a complex locus with two promoters. Two mutant alleles of cog-1 differentially affect alternative transcripts and cause different phenotypes, suggesting that the two forms of cog-1 have distinct functions in C. elegans.

  14. High qualitative and quantitative conservation of alternative splicing in Caenorhabditis elegans and Caenorhabditis briggsae

    DEFF Research Database (Denmark)

    Rukov, Jakob Lewin; Irimia, Manuel; Mørk, Søren;

    2007-01-01

    Alternative splicing (AS) is an important contributor to proteome diversity and is regarded as an explanatory factor for the relatively low number of human genes compared with less complex animals. To assess the evolutionary conservation of AS and its developmental regulation, we have investigated...... the qualitative and quantitative expression of 21 orthologous alternative splice events through the development of 2 nematode species separated by 85-110 Myr of evolutionary time. We demonstrate that most of these alternative splice events present in Caenorhabditis elegans are conserved in Caenorhabditis briggsae...... mechanisms controlling AS are to a large extent conserved during the evolution of Caenorhabditis. This strong conservation indicates that both major and minor splice forms have important functional roles and that the relative quantities in which they are expressed are crucial. Our results therefore suggest...

  15. Power law relationship between cell cycle duration and cell volume in the early embryonic development of Caenorhabditis elegans.

    Science.gov (United States)

    Arata, Yukinobu; Takagi, Hiroaki; Sako, Yasushi; Sawa, Hitoshi

    2014-01-01

    Cell size is a critical factor for cell cycle regulation. In Xenopus embryos after midblastula transition (MBT), the cell cycle duration elongates in a power law relationship with the cell radius squared. This correlation has been explained by the model that cell surface area is a candidate to determine cell cycle duration. However, it remains unknown whether this second power law is conserved in other animal embryos. Here, we found that the relationship between cell cycle duration and cell size in Caenorhabditis elegans embryos exhibited a power law distribution. Interestingly, the powers of the time-size relationship could be grouped into at least three classes: highly size-correlated, moderately size-correlated, and potentially a size-non-correlated class according to C. elegans founder cell lineages (1.2, 0.81, and power law relationship is conserved in Xenopus and C. elegans, while the absolute powers in C. elegans were different from that in Xenopus. Furthermore, we found that the volume ratio between the nucleus and cell exhibited a power law relationship in the size-correlated classes. The power of the volume relationship was closest to that of the time-size relationship in the highly size-correlated class. This correlation raised the possibility that the time-size relationship, at least in the highly size-correlated class, is explained by the volume ratio of nuclear size and cell size. Thus, our quantitative measurements shed a light on the possibility that early embryonic C. elegans cell cycle duration is coordinated with cell size as a result of geometric constraints between intracellular structures.

  16. Toxicological Effects of Fullerenes on Caenorhabditis elegans

    Science.gov (United States)

    Schomaker, Justin; Snook, Renee; Howell, Carina

    2014-03-01

    The nematode species Caenorhabditis elegans is a useful genetic model organism due to its simplicity and the substantial molecular, genetic, and developmental knowledge about the species. In this study, this species was used to test the toxicological effects of C60 fullerene nanoparticles. In previous studies using rats, a solution of C60 fullerenes in olive oil proved to extend the life of the subjects. The purpose of this experiment was to subject C. elegans to varying concentrations of C60 fullerenes and observe their toxicological effects. Initial findings indicate a link between fullerene exposure and enlargement of the vulva as well as the formation of a small nodule at the base of the tail in some individuals. While the fullerenes are not lethally toxic in C. elegans, results will be presented that pertain to changes in life span and progeny of the nematodes exposed to varying concentrations of fullerenes as well as the mechanisms of toxicity. High magnification imaging via SEM and/or AFM will be used to characterize the fullerene nanoparticles. Testing the toxicity of fullerenes in a wide variety of organisms will lead to a more complete understanding of the effects of fullerenes on living organisms to ultimately understand their effects in humans. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047, DUE-0806660 and Lock Haven FPDC grants.

  17. Acute carbon dioxide avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Hallem, Elissa A; Sternberg, Paul W

    2008-06-10

    Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO2 avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO2 responsiveness via the insulin and TGFbeta signaling pathways. CO2 response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO2 avoidance. Our results demonstrate that C. elegans senses and responds to CO2 using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm.

  18. Bacterial attraction and quorum sensing inhibition in Caenorhabditis elegans exudates

    Science.gov (United States)

    Caenorhabditis elegans, a bacterivorous soil nematode, lives in a complex environment that requires chemical communication for mating, monitoring population density, recognition of food, avoidance of pathogenic microbes, and other essential ecological functions. Despite being one of the best-studied...

  19. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    2013-01-01

    The susceptibility of Caenorhabditis elegans to different virulent phenotypes of Pseudomonas aeruginosa makes the worms an excellent model for studying host-pathogen interactions. Including the recently described liquid killing, five different killing assays are now available offering superb possibi

  20. Caenorhabditis elegans behavioral genetics: where are the knobs?

    Directory of Open Access Journals (Sweden)

    Avery Leon

    2010-06-01

    Full Text Available Abstract Thousands of behavioral mutants of Caenorhabditis elegans have been studied. I suggest a set of criteria by which some genes important in the evolution of behavior might be recognized, and identify neuropeptide signaling pathways as candidates.

  1. Systematic and quantitative analysis of the early embryonic development of Caenorhabditis elegans

    OpenAIRE

    Krüger, Angela

    2012-01-01

    El nemátodo Caernorhabditis elegans ofrece la posibilidad de estudiar el desarrollo embrionario con una resolución celular. En esta tesis, describo el uso de un algoritmo semi-automático de seguimiento nuclear para analizar movimientos celulares en el embrión temprano, así como la manera en que el embrión responde a deformaciones mecánicas y a perturbaciones genéticas. Durante el proceso de gastrulación, observamos que ciertas células no solo ingresan al interior del embrión, pero también egr...

  2. Effects of Essential Amino Acids on Caenorhabditis elegans Development%必需氨基酸对秀丽新杆线虫发育的影响

    Institute of Scientific and Technical Information of China (English)

    于笑坤; 邢述; 付学奇; 赵志壮; 马俊锋

    2013-01-01

    All food resources were removed except 10 kinds of essential amino acids to explore the effects of these essential amino acids on Caenorhabditis elegans development. The results show that without any nutrient resources, C. elegans stayed in diapause and did not have a significant body length growth. However, C. elegans living with essential amino acids had significantly longer body length compared to diapause worms in control group. Our study demonstrates the effects of essential amino acids on C. elegans development have provided basis and proof for further functional and mechanism study on essential amino acids.%在秀丽新杆线虫培养的过程中去除其他营养来源,仅在培养基中加入线虫所需的10种必需氨基酸,进而考察该类氨基酸对线虫发育过程的影响.结果表明:未摄取任何营养物质的线虫始终处于滞育期,面摄入必需氨基酸的线虫体长明显长于维持在滞育期的对照组,其中色氨酸和组氨酸在该过程中发挥了关键性的作用.

  3. Caenorhabditis elegans: a simple nematode infection model for Penicillium marneffei.

    Directory of Open Access Journals (Sweden)

    Xiaowen Huang

    Full Text Available Penicillium marneffei, one of the most important thermal dimorphic fungi, is a severe threat to the life of immunocompromised patients. However, the pathogenic mechanisms of P. marneffei remain largely unknown. In this work, we developed a model host by using nematode Caenorhabditis elegans to investigate the virulence of P. marneffei. Using two P. marneffei clinical isolate strains 570 and 486, we revealed that in both liquid and solid media, the ingestion of live P. marneffei was lethal to C. elegans (P<0.001. Meanwhile, our results showed that the strain 570, which can produce red pigment, had stronger pathogenicity in C. elegans than the strain 486, which can't produce red pigment (P<0.001. Microscopy showed the formation of red pigment and hyphae within C. elegans after incubation with P. marneffei for 4 h, which are supposed to be two contributors in nematodes killing. In addition, we used C. elegans as an in vivo model to evaluate different antifungal agents against P. marneffei, and found that antifungal agents including amphotericin B, terbinafine, fluconazole, itraconazole and voriconazole successfully prolonged the survival of nematodesinfected by P. marneffei. Overall, this alternative model host can provide us an easy tool to study the virulence of P. marneffei and screen antifungal agents.

  4. Anthelmintic drugs and nematicides: studies in Caenorhabditis elegans.

    Science.gov (United States)

    Holden-Dye, Lindy; Walker, Robert J

    2014-12-16

    Parasitic nematodes infect many species of animals throughout the phyla, including humans. Moreover, nematodes that parasitise plants are a global problem for agriculture. As such, these nematodes place a major burden on human health, on livestock production, on the welfare of companion animals and on crop production. In the 21st century there are two major challenges posed by the wide-spread prevalence of parasitic nematodes. First, many anthelmintic drugs are losing their effectiveness because nematode strains with resistance are emerging. Second, serious concerns regarding the environmental impact of the nematicides used for crop protection have prompted legislation to remove them from use, leaving agriculture at increased risk from nematode pests. There is clearly a need for a concerted effort to address these challenges. Over the last few decades the free-living nematode Caenorhabditis elegans has provided the opportunity to use molecular genetic techniques for mode of action studies for anthelmintics and nematicides. These approaches continue to be of considerable value. Less fruitful so far, but nonetheless potentially very useful, has been the direct use of C. elegans for anthelmintic and nematicide discovery programmes. Here we provide an introduction to the use of C. elegans as a 'model' parasitic nematode, briefly review the study of nematode control using C. elegans and highlight approaches that have been of particular value with a view to facilitating wider-use of C. elegans as a platform for anthelmintic and nematicide discovery and development.

  5. Caenorhabditis elegans - A model system for space biology studies

    Science.gov (United States)

    Johnson, Thomas E.; Nelson, Gregory A.

    1991-01-01

    The utility of the nematode Caenorhabditis elegans in studies spanning aspects of development, aging, and radiobiology is reviewed. These topics are interrelated via cellular and DNA repair processes especially in the context of oxidative stress and free-radical metabolism. The relevance of these research topics to problems in space biology is discussed and properties of the space environment are outlined. Exposure to the space-flight environment can induce rapid changes in living systems that are similar to changes occurring during aging; manipulation of these environmental parameters may represent an experimental strategy for studies of development and senescence. The current and future opportunities for such space-flight experimentation are presented.

  6. Chemotaxis of crawling and swimming Caenorhabditis Elegans

    Science.gov (United States)

    Patel, Amar; Bilbao, Alejandro; Padmanabhan, Venkat; Khan, Zeina; Armstrong, Andrew; Rumbaugh, Kendra; Vanapalli, Siva; Blawzdziewicz, Jerzy

    2012-11-01

    A soil-dwelling nematode Caenorhabditis Elegans efficiently navigates through complex environments, responding to chemical signals to find food or avoid danger. According to previous studies, the nematode uses both gradual-turn and run-and-tumble strategies to move in the direction of the increasing concentration of chemical attractants. We show that both these chemotaxis strategies can be described using our kinematic model [PLoS ONE, 7: e40121 (2012)] in which harmonic-curvature modes represent elementary nematode movements. In our chemotaxis model, the statistics of mode changes is governed by the time history of the chemoattractant concentration at the position of the nematode head. We present results for both nematodes crawling without transverse slip and for swimming nematodes. This work was supported by NSF grant No. CBET 1059745.

  7. Caenorhabditis elegans chemical biology: lessons from small molecules

    Science.gov (United States)

    How can we complement Caenorhabditis elegans genomics and proteomics with a comprehensive structural and functional annotation of its metabolome? Several lines of evidence indicate that small molecules of largely undetermined structure play important roles in C. elegans biology, including key pathw...

  8. Genetic screens in Caenorhabditis elegans models for neurodegenerative diseases

    NARCIS (Netherlands)

    Alvarenga Fernandes Sin, Olga; Michels, Helen; Nollen, Ellen A. A.

    2014-01-01

    Caenorhabditis elegans comprises unique features that make it an attractive model organism in diverse fields of biology. Genetic screens are powerful to identify genes and C. elegans can be customized to forward or reverse genetic screens and to establish gene function. These genetic screens can be

  9. Sensory processing by neural circuits in Caenorhabditis elegans.

    Science.gov (United States)

    Whittaker, Allyson J; Sternberg, Paul W

    2004-08-01

    The anatomical and developmental constancy of Caenorhabditis elegans belies the complexity of its numerically small nervous system. Indeed, there is an increased appreciation of C. elegans as an organism to study systems level questions. Many recent studies focus on the circuits that control locomotion, egg-laying, and male mating behaviors and their modulation by multiple sensory stimuli.

  10. Illuminating neural circuits and behaviour in Caenorhabditis elegans with optogenetics.

    Science.gov (United States)

    Fang-Yen, Christopher; Alkema, Mark J; Samuel, Aravinthan D T

    2015-09-19

    The development of optogenetics, a family of methods for using light to control neural activity via light-sensitive proteins, has provided a powerful new set of tools for neurobiology. These techniques have been particularly fruitful for dissecting neural circuits and behaviour in the compact and transparent roundworm Caenorhabditis elegans. Researchers have used optogenetic reagents to manipulate numerous excitable cell types in the worm, from sensory neurons, to interneurons, to motor neurons and muscles. Here, we show how optogenetics applied to this transparent roundworm has contributed to our understanding of neural circuits.

  11. Endoderm development in Caenorhabditis elegans: the synergistic action of ELT-2 and -7 mediates the specification→differentiation transition.

    Science.gov (United States)

    Sommermann, Erica M; Strohmaier, Keith R; Maduro, Morris F; Rothman, Joel H

    2010-11-01

    The transition from specification of cell identity to the differentiation of cells into an appropriate and enduring state is critical to the development of embryos. Transcriptional profiling in Caenorhabditis elegans has revealed a large number of genes that are expressed in the fully differentiated intestine; however, no regulatory factor has been found to be essential to initiate their expression once the endoderm has been specified. These gut-expressed genes possess a preponderance of GATA factor binding sites and one GATA factor, ELT-2, fulfills the expected characteristics of a key regulator of these genes based on its persistent expression exclusively in the developing and differentiated intestine and its ability to bind these regulatory sites. However, a striking characteristic of elt-2(0) knockout mutants is that while they die shortly after hatching owing to an obstructed gut passage, they nevertheless contain a gut that has undergone complete morphological differentiation. We have discovered a second gut-specific GATA factor, ELT-7, that profoundly synergizes with ELT-2 to create a transcriptional switch essential for gut cell differentiation. ELT-7 is first expressed in the early endoderm lineage and, when expressed ectopically, is sufficient to activate gut differentiation in nonendodermal progenitors. elt-7 is transcriptionally activated by the redundant endoderm-specifying factors END-1 and -3, and its product in turn activates both its own expression and that of elt-2, constituting an apparent positive feedback system. While elt-7 loss-of-function mutants lack a discernible phenotype, simultaneous loss of both elt-7 and elt-2 results in a striking all-or-none block to morphological differentiation of groups of gut cells with a region-specific bias, as well as reduced or abolished gut-specific expression of a number of terminal differentiation genes. ELT-2 and -7 synergize not only in activation of gene expression but also in repression of a gene that

  12. Caenorhabditis elegans ATAD-3 modulates mitochondrial iron and heme homeostasis.

    Science.gov (United States)

    van den Ecker, Daniela; Hoffmann, Michael; Müting, Gesine; Maglioni, Silvia; Herebian, Diran; Mayatepek, Ertan; Ventura, Natascia; Distelmaier, Felix

    2015-11-13

    ATAD3 (ATPase family AAA domain-containing protein 3) is a mitochondrial protein, which is essential for cell viability and organismal development. ATAD3 has been implicated in several important cellular processes such as apoptosis regulation, respiratory chain function and steroid hormone biosynthesis. Moreover, altered expression of ATAD3 has been associated with several types of cancer. However, the exact mechanisms underlying ATAD3 effects on cellular metabolism remain largely unclear. Here, we demonstrate that Caenorhabditis elegans ATAD-3 is involved in mitochondrial iron and heme homeostasis. Knockdown of atad-3 caused mitochondrial iron- and heme accumulation. This was paralleled by changes in the expression levels of several iron- and heme-regulatory genes as well as an increased heme uptake. In conclusion, our data indicate a regulatory role of C. elegans ATAD-3 in mitochondrial iron and heme metabolism.

  13. Stochastic left-right neuronal asymmetry in Caenorhabditis elegans.

    Science.gov (United States)

    Alqadah, Amel; Hsieh, Yi-Wen; Xiong, Rui; Chuang, Chiou-Fen

    2016-12-19

    Left-right asymmetry in the nervous system is observed across species. Defects in left-right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing 'C' (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC(OFF) (default) and AWC(ON) (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.

  14. Caenorhabditis elegans Egg-Laying Detection and Behavior Study Using Image Analysis

    Directory of Open Access Journals (Sweden)

    Palm Megan

    2005-01-01

    Full Text Available Egg laying is an important phase of the life cycle of the nematode Caenorhabditis elegans (C. elegans. Previous studies examined egg-laying events manually. This paper presents a method for automatic detection of egg-laying onset using deformable template matching and other morphological image analysis techniques. Some behavioral changes surrounding egg-laying events are also studied. The results demonstrate that the computer vision tools and the algorithm developed here can be effectively used to study C. elegans egg-laying behaviors. The algorithm developed is an essential part of a machine-vision system for C. elegans tracking and behavioral analysis.

  15. Dietary supplementation of polyunsaturated fatty acids in Caenorhabditis elegans.

    Science.gov (United States)

    Deline, Marshall L; Vrablik, Tracy L; Watts, Jennifer L

    2013-11-29

    Fatty acids are essential for numerous cellular functions. They serve as efficient energy storage molecules, make up the hydrophobic core of membranes, and participate in various signaling pathways. Caenorhabditis elegans synthesizes all of the enzymes necessary to produce a range of omega-6 and omega-3 fatty acids. This, combined with the simple anatomy and range of available genetic tools, make it an attractive model to study fatty acid function. In order to investigate the genetic pathways that mediate the physiological effects of dietary fatty acids, we have developed a method to supplement the C. elegans diet with unsaturated fatty acids. Supplementation is an effective means to alter the fatty acid composition of worms and can also be used to rescue defects in fatty acid-deficient mutants. Our method uses nematode growth medium agar (NGM) supplemented with fatty acid sodium salts. The fatty acids in the supplemented plates become incorporated into the membranes of the bacterial food source, which is then taken up by the C. elegans that feed on the supplemented bacteria. We also describe a gas chromatography protocol to monitor the changes in fatty acid composition that occur in supplemented worms. This is an efficient way to supplement the diets of both large and small populations of C. elegans, allowing for a range of applications for this method.

  16. ROS in aging Caenorhabditis elegans: damage or signaling?

    Science.gov (United States)

    Back, Patricia; Braeckman, Bart P; Matthijssens, Filip

    2012-01-01

    Many insights into the mechanisms and signaling pathways underlying aging have resulted from research on the nematode Caenorhabditis elegans. In this paper, we discuss the recent findings that emerged using this model organism concerning the role of reactive oxygen species (ROS) in the aging process. The accrual of oxidative stress and damage has been the predominant mechanistic explanation for the process of aging for many years, but reviewing the recent studies in C. elegans calls this theory into question. Thus, it becomes more and more evident that ROS are not merely toxic byproducts of the oxidative metabolism. Rather it seems more likely that tightly controlled concentrations of ROS and fluctuations in redox potential are important mediators of signaling processes. We therefore discuss some theories that explain how redox signaling may be involved in aging and provide some examples of ROS functions and signaling in C. elegans metabolism. To understand the role of ROS and the redox status in physiology, stress response, development, and aging, there is a rising need for accurate and reversible in vivo detection. Therefore, we comment on some methods of ROS and redox detection with emphasis on the implementation of genetically encoded biosensors in C. elegans.

  17. The Caenorhabditis elegans lipidome: A primer for lipid analysis in Caenorhabditis elegans.

    Science.gov (United States)

    Witting, Michael; Schmitt-Kopplin, Philippe

    2016-01-01

    Lipids play important roles in biology, ranging from building blocks of membranes to signaling lipids. The nematode and model organism Caenorhabditis elegans has been used to explore lipid metabolism and several techniques for their analysis have been employed. These techniques include different possibilities ranging from visualization of lipid droplets, analysis of total fatty acids to analysis of complex lipids using lipidomics approaches. Lipidomics evolved from metabolomics, the latest off-spring of the "omics"-technologies and aims to characterize the lipid content of a given organism or system. Although being an extensively studied model organism, only a few applications of lipidomics to C. elegans have been reported to far, but the number is steadily increasing with more applications expected in the near future. This review gives an overview on the C. elegans lipidome, lipid classes it contains and ways to analyze them. It serves as primer for scientists interested in studying lipids in this model organism and list methods used so far and what information can be derived from them. Lastly, challenges and future (methodological) research directions, together with new methods potentially useful for C. elegans lipid research are discussed.

  18. The secretory pathway calcium ATPase PMR-1/SPCA1 has essential roles in cell migration during Caenorhabditis elegans embryonic development.

    Directory of Open Access Journals (Sweden)

    Vida Praitis

    2013-05-01

    Full Text Available Maintaining levels of calcium in the cytosol is important for many cellular events, including cell migration, where localized regions of high calcium are required to regulate cytoskeletal dynamics, contractility, and adhesion. Studies show inositol-trisphosphate receptors (IP3R and ryanodine receptors (RyR, which release calcium into the cytosol, are important regulators of cell migration. Similarly, proteins that return calcium to secretory stores are likely to be important for cell migration. The secretory protein calcium ATPase (SPCA is a Golgi-localized protein that transports calcium from the cytosol into secretory stores. SPCA has established roles in protein processing, metal homeostasis, and inositol-trisphosphate signaling. Defects in the human SPCA1/ATP2C1 gene cause Hailey-Hailey disease (MIM# 169600, a genodermatosis characterized by cutaneous blisters and fissures as well as keratinocyte cell adhesion defects. We have determined that PMR-1, the Caenorhabditis elegans ortholog of SPCA1, plays an essential role in embryogenesis. Pmr-1 strains isolated from genetic screens show terminal phenotypes, such as ventral and anterior enclosure failures, body morphogenesis defects, and an unattached pharynx, which are caused by earlier defects during gastrulation. In Pmr-1 embryos, migration rates are significantly reduced for cells moving along the embryo surface, such as ventral neuroblasts, C-derived, and anterior-most blastomeres. Gene interaction experiments show changing the activity of itr-1/IP3R and unc-68/RyR modulates levels of embryonic lethality in Pmr-1 strains, indicating pmr-1 acts with these calcium channels to regulate cell migration. This analysis reveals novel genes involved in C. elegans cell migration, as well as a new role in cell migration for the highly conserved SPCA gene family.

  19. The secretory pathway calcium ATPase PMR-1/SPCA1 has essential roles in cell migration during Caenorhabditis elegans embryonic development.

    Science.gov (United States)

    Praitis, Vida; Simske, Jeffrey; Kniss, Sarah; Mandt, Rebecca; Imlay, Leah; Feddersen, Charlotte; Miller, Michael B; Mushi, Juliet; Liszewski, Walter; Weinstein, Rachel; Chakravorty, Adityarup; Ha, Dae-Gon; Schacht Farrell, Angela; Sullivan-Wilson, Alexander; Stock, Tyson

    2013-05-01

    Maintaining levels of calcium in the cytosol is important for many cellular events, including cell migration, where localized regions of high calcium are required to regulate cytoskeletal dynamics, contractility, and adhesion. Studies show inositol-trisphosphate receptors (IP3R) and ryanodine receptors (RyR), which release calcium into the cytosol, are important regulators of cell migration. Similarly, proteins that return calcium to secretory stores are likely to be important for cell migration. The secretory protein calcium ATPase (SPCA) is a Golgi-localized protein that transports calcium from the cytosol into secretory stores. SPCA has established roles in protein processing, metal homeostasis, and inositol-trisphosphate signaling. Defects in the human SPCA1/ATP2C1 gene cause Hailey-Hailey disease (MIM# 169600), a genodermatosis characterized by cutaneous blisters and fissures as well as keratinocyte cell adhesion defects. We have determined that PMR-1, the Caenorhabditis elegans ortholog of SPCA1, plays an essential role in embryogenesis. Pmr-1 strains isolated from genetic screens show terminal phenotypes, such as ventral and anterior enclosure failures, body morphogenesis defects, and an unattached pharynx, which are caused by earlier defects during gastrulation. In Pmr-1 embryos, migration rates are significantly reduced for cells moving along the embryo surface, such as ventral neuroblasts, C-derived, and anterior-most blastomeres. Gene interaction experiments show changing the activity of itr-1/IP3R and unc-68/RyR modulates levels of embryonic lethality in Pmr-1 strains, indicating pmr-1 acts with these calcium channels to regulate cell migration. This analysis reveals novel genes involved in C. elegans cell migration, as well as a new role in cell migration for the highly conserved SPCA gene family.

  20. Genome-wide identification of binding sites defines distinct functions for Caenorhabditis elegans PHA-4/FOXA in development and environmental response.

    Directory of Open Access Journals (Sweden)

    Mei Zhong

    2010-02-01

    Full Text Available Transcription factors are key components of regulatory networks that control development, as well as the response to environmental stimuli. We have established an experimental pipeline in Caenorhabditis elegans that permits global identification of the binding sites for transcription factors using chromatin immunoprecipitation and deep sequencing. We describe and validate this strategy, and apply it to the transcription factor PHA-4, which plays critical roles in organ development and other cellular processes. We identified thousands of binding sites for PHA-4 during formation of the embryonic pharynx, and also found a role for this factor during the starvation response. Many binding sites were found to shift dramatically between embryos and starved larvae, from developmentally regulated genes to genes involved in metabolism. These results indicate distinct roles for this regulator in two different biological processes and demonstrate the versatility of transcription factors in mediating diverse biological roles.

  1. Screening for microbial metabolites affecting phenotype of Caenorhabditis elegans.

    Science.gov (United States)

    Yamamuro, Daisuke; Uchida, Ryuji; Takahashi, Yoko; Masuma, Rokuro; Tomoda, Hiroshi

    2011-01-01

    Microbial samples, including our library of known microbial compounds (ca. 300) and microbial culture broths (ca. 9000), were screened for small molecules affecting the phenotype of Caenorhabditis elegans. As a result, seven known compounds were found to induce phenotypic abnormality of C. elegans. Staurosporine exhibited morphological defects in the vulva and tail of C. elegans, avermectin B1a exhibited hatching inhibition of starting eggs on day 1 at 25-100 µM and growth inhibition at 0.01-12.5 µM, siccanin and antimycin A inhibited the growth of C. elegans, and fluorouracil inhibited hatching of eggs newly spawned by adult C. elegans. Toromycin induced morphological defects in the intestine. 5-(4-Methoxyphenyl)-oxazole, isolated as a fungal metabolite for the first time, inhibited the hatching of eggs newly spawned by adult C. elegans.

  2. Pan-neuronal imaging in roaming Caenorhabditis elegans.

    Science.gov (United States)

    Venkatachalam, Vivek; Ji, Ni; Wang, Xian; Clark, Christopher; Mitchell, James Kameron; Klein, Mason; Tabone, Christopher J; Florman, Jeremy; Ji, Hongfei; Greenwood, Joel; Chisholm, Andrew D; Srinivasan, Jagan; Alkema, Mark; Zhen, Mei; Samuel, Aravinthan D T

    2016-02-23

    We present an imaging system for pan-neuronal recording in crawling Caenorhabditis elegans. A spinning disk confocal microscope, modified for automated tracking of the C. elegans head ganglia, simultaneously records the activity and position of ∼80 neurons that coexpress cytoplasmic calcium indicator GCaMP6s and nuclear localized red fluorescent protein at 10 volumes per second. We developed a behavioral analysis algorithm that maps the movements of the head ganglia to the animal's posture and locomotion. Image registration and analysis software automatically assigns an index to each nucleus and calculates the corresponding calcium signal. Neurons with highly stereotyped positions can be associated with unique indexes and subsequently identified using an atlas of the worm nervous system. To test our system, we analyzed the brainwide activity patterns of moving worms subjected to thermosensory inputs. We demonstrate that our setup is able to uncover representations of sensory input and motor output of individual neurons from brainwide dynamics. Our imaging setup and analysis pipeline should facilitate mapping circuits for sensory to motor transformation in transparent behaving animals such as C. elegans and Drosophila larva.

  3. Searching WormBase for information about Caenorhabditis elegans.

    Science.gov (United States)

    Schwarz, Erich M; Sternberg, Paul W

    2006-07-01

    WormBase is the major public biological database for the nematode Caenorhabditis elegans. It is meant to be useful to any biologist who wants to use C. elegans, whatever his or her specialty. WormBase contains information about the genomic sequence of C. elegans, its genes and their products, and its higher-level traits such as gene expression patterns and neuronal connectivity. WormBase also contains genomic sequences and gene structures of C. briggsae and C. remanei, two closely related worms. These data are interconnected, so that a search beginning with one object (such as a gene) can be directed to related objects of a different type (e.g., the DNA sequence of the gene or the cells in which the gene is active). One can also perform searches for complex data sets. The WormBase developers group actively invites suggestions for improvements from the database users. WormBase's source code and underlying database are freely available for local installation and modification.

  4. Characterisation of Caenorhabditis elegans sperm transcriptome and proteome

    OpenAIRE

    Ma, Xuan; Zhu, Yingjie; Li, Chunfang; Xue, Peng; Zhao, Yanmei; Chen, Shilin; Yang, Fuquan; Miao, Long

    2014-01-01

    Background Although sperm is transcriptionally and translationally quiescent, complex populations of RNAs, including mRNAs and non-coding RNAs, exist in sperm. Previous microarray analysis of germ cell mutants identified hundreds of sperm genes in Caenorhabditis elegans. To take a more comprehensive view on C. elegans sperm genes, here, we isolate highly pure sperm cells and employ high-throughput technologies to obtain sperm transcriptome and proteome. Results First, sperm transcriptome cons...

  5. Transfer characteristics of a thermosensory synapse in Caenorhabditis elegans

    OpenAIRE

    Narayan, Anusha; Laurent, Gilles; Sternberg, Paul W.

    2011-01-01

    Caenorhabditis elegans is a compact, attractive system for neural circuit analysis. An understanding of the functional dynamics of neural computation requires physiological analyses. We undertook the characterization of transfer at a central synapse in C. elegans by combining optical stimulation of targeted neurons with electrophysiological recordings. We show that the synapse between AFD and AIY, the first stage in the thermotactic circuit, exhibits excitatory, tonic, and graded release. We...

  6. Nucleotide Excision Repair in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Hannes Lans

    2011-01-01

    Full Text Available Nucleotide excision repair (NER plays an essential role in many organisms across life domains to preserve and faithfully transmit DNA to the next generation. In humans, NER is essential to prevent DNA damage-induced mutation accumulation and cell death leading to cancer and aging. NER is a versatile DNA repair pathway that repairs many types of DNA damage which distort the DNA helix, such as those induced by solar UV light. A detailed molecular model of the NER pathway has emerged from in vitro and live cell experiments, particularly using model systems such as bacteria, yeast, and mammalian cell cultures. In recent years, the versatility of the nematode C. elegans to study DNA damage response (DDR mechanisms including NER has become increasingly clear. In particular, C. elegans seems to be a convenient tool to study NER during the UV response in vivo, to analyze this process in the context of a developing and multicellular organism, and to perform genetic screening. Here, we will discuss current knowledge gained from the use of C. elegans to study NER and the response to UV-induced DNA damage.

  7. The temporal scaling of Caenorhabditis elegans ageing

    Science.gov (United States)

    Stroustrup, Nicholas; Anthony, Winston E.; Nash, Zachary M.; Gowda, Vivek; Gomez, Adam; López-Moyado, Isaac F.; Apfeld, Javier; Fontana, Walter

    2016-02-01

    The process of ageing makes death increasingly likely, involving a random aspect that produces a wide distribution of lifespan even in homogeneous populations. The study of this stochastic behaviour may link molecular mechanisms to the ageing process that determines lifespan. Here, by collecting high-precision mortality statistics from large populations, we observe that interventions as diverse as changes in diet, temperature, exposure to oxidative stress, and disruption of genes including the heat shock factor hsf-1, the hypoxia-inducible factor hif-1, and the insulin/IGF-1 pathway components daf-2, age-1, and daf-16 all alter lifespan distributions by an apparent stretching or shrinking of time. To produce such temporal scaling, each intervention must alter to the same extent throughout adult life all physiological determinants of the risk of death. Organismic ageing in Caenorhabditis elegans therefore appears to involve aspects of physiology that respond in concert to a diverse set of interventions. In this way, temporal scaling identifies a novel state variable, r(t), that governs the risk of death and whose average decay dynamics involves a single effective rate constant of ageing, kr. Interventions that produce temporal scaling influence lifespan exclusively by altering kr. Such interventions, when applied transiently even in early adulthood, temporarily alter kr with an attendant transient increase or decrease in the rate of change in r and a permanent effect on remaining lifespan. The existence of an organismal ageing dynamics that is invariant across genetic and environmental contexts provides the basis for a new, quantitative framework for evaluating the manner and extent to which specific molecular processes contribute to the aspect of ageing that determines lifespan.

  8. An activating mutation in sos-1 identifies its Dbl domain as a critical inhibitor of the epidermal growth factor receptor pathway during Caenorhabditis elegans vulval development.

    Science.gov (United States)

    Modzelewska, Katarzyna; Elgort, Marc G; Huang, Jingyu; Jongeward, Gregg; Lauritzen, Amara; Yoon, Charles H; Sternberg, Paul W; Moghal, Nadeem

    2007-05-01

    Proper regulation of receptor tyrosine kinase (RTK)-Ras-mitogen-activated protein kinase (MAPK) signaling pathways is critical for normal development and the prevention of cancer. SOS is a dual-function guanine nucleotide exchange factor (GEF) that catalyzes exchange on Ras and Rac. Although the physiologic role of SOS and its CDC25 domain in RTK-mediated Ras activation is well established, the in vivo function of its Dbl Rac GEF domain is less clear. We have identified a novel gain-of-function missense mutation in the Dbl domain of Caenorhabditis elegans SOS-1 that promotes epidermal growth factor receptor (EGFR) signaling in vivo. Our data indicate that a major developmental function of the Dbl domain is to inhibit EGF-dependent MAPK activation. The amount of inhibition conferred by the Dbl domain is equal to that of established trans-acting inhibitors of the EGFR pathway, including c-Cbl and RasGAP, and more than that of MAPK phosphatase. In conjunction with molecular modeling, our data suggest that the C. elegans mutation, as well as an equivalent mutation in human SOS1, activates the MAPK pathway by disrupting an autoinhibitory function of the Dbl domain on Ras activation. Our work suggests that functionally similar point mutations in humans could directly contribute to disease.

  9. A mutational analysis of Caenorhabditis elegans in space

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yang [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Lai, Kenneth [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Cheung, Iris [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Youds, Jillian [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Tarailo, Maja [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Tarailo, Sanja [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada); Rose, Ann [Department of Medical Genetics, University of British Columbia, Life Sciences Centre, Room 1364-2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3 (Canada)]. E-mail: arose@gene.nce.ubc.ca

    2006-10-10

    The International Caenorhabditis elegans Experiment First Flight (ICE-First) was a project using C. elegans as a model organism to study the biological effects of short duration spaceflight (11 days in the International Space Station). As a member of the ICE-First research team, our group focused on the mutational effects of spaceflight. Several approaches were taken to measure mutational changes that occurred during the spaceflight including measurement of the integrity of poly-G/poly-C tracts, determination of the mutation frequency in the unc-22 gene, analysis of lethal mutations captured by the genetic balancer eT1(III;V), and identification of alterations in telomere length. By comparing the efficiency, sensitivity, and convenience of these methods, we deduced that the eT1 balancer system is well-suited for capturing, maintaining and recovering mutational events that occur over several generations during spaceflight. In the course of this experiment, we have extended the usefulness of the eT1 balancer system by identifying the physical breakpoints of the eT1 translocation and have developed a PCR assay to follow the eT1 chromosomes. C. elegans animals were grown in a defined liquid media during the spaceflight. This is the first analysis of genetic changes in C. elegans grown in the defined media. Although no significant difference in mutation rate was detected between spaceflight and control samples, which is not surprising given the short duration of the spaceflight, we demonstrate here the utility of worms as an integrating biological dosimeter for spaceflight.

  10. Single-copy insertion of transgenes in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Frøkjaer-Jensen, Christian; Davis, M Wayne; Hopkins, Christopher E;

    2008-01-01

    At present, transgenes in Caenorhabditis elegans are generated by injecting DNA into the germline. The DNA assembles into a semistable extrachromosomal array composed of many copies of injected DNA. These transgenes are typically overexpressed in somatic cells and silenced in the germline. We have...

  11. An Elegant Mind: Learning and Memory in "Caenorhabditis elegans"

    Science.gov (United States)

    Ardiel, Evan L.; Rankin, Catharine H.

    2010-01-01

    This article reviews the literature on learning and memory in the soil-dwelling nematode "Caenorhabditis elegans." Paradigms include nonassociative learning, associative learning, and imprinting, as worms have been shown to habituate to mechanical and chemical stimuli, as well as learn the smells, tastes, temperatures, and oxygen levels that…

  12. Concentration dependent differential activity of signalling molecules in Caenorhabditis elegans

    Science.gov (United States)

    Caenorhabditis elegans employs specific glycosides of the dideoxysugar ascarylose (the ‘ascarosides’) for monitoring population density/ dauer formation and finding mates. A synergistic blend of three ascarosides, called ascr#2, ascr#3 and ascr#4 acts as a dauer pheromone at a high concentration na...

  13. Lack of the RNA chaperone hfq attenuates pathogenicity of several Escherichia coli pathotypes towards Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Bojer, Martin Saxtorph; Jakobsen, Henrik; Struve, Carsten;

    2012-01-01

    as a model for virulence characterization and screening for novel antimicrobial entities. Several E. coli human pathotypes are also pathogenic towards C. elegans, and we show here that lack of the RNA chaperone Hfq significantly reduces pathogenicity of VTEC, EAEC, and UPEC in the nematode model. Thus, Hfq...... is intrinsically essential to pathogenic E. coli for survival and virulence exerted in the C. elegans host.......Escherichia coli is an important agent of Gram-negative bacterial infections worldwide, being one of the leading causes of diarrhoea and urinary tract infections. Strategies to understand pathogenesis and develop therapeutic compounds include the use of the nematode Caenorhabditis elegans...

  14. Translational control in the Caenorhabditis elegans germ line.

    Science.gov (United States)

    Nousch, Marco; Eckmann, Christian R

    2013-01-01

    Translational control is a prevalent form of gene expression regulation in the Caenorhabditis elegans germ line. Linking the amount of protein synthesis to mRNA quantity and translational accessibility in the cell cytoplasm provides unique advantages over DNA-based controls for developing germ cells. This mode of gene expression is especially exploited in germ cell fate decisions and during oogenesis, when the developing oocytes stockpile hundreds of different mRNAs required for early embryogenesis. Consequently, a dense web of RNA regulators, consisting of diverse RNA-binding proteins and RNA-modifying enzymes, control the translatability of entire mRNA expression programs. These RNA regulatory networks are tightly coupled to germ cell developmental progression and are themselves under translational control. The underlying molecular mechanisms and RNA codes embedded in the mRNA molecules are beginning to be understood. Hence, the C. elegans germ line offers fertile grounds for discovering post-transcriptional mRNA regulatory mechanisms and emerges as great model for a systems level understanding of translational control during development.

  15. Manganese Disturbs Metal and Protein Homeostasis in Caenorhabditis elegans

    Science.gov (United States)

    Angeli, Suzanne; Barhydt, Tracy; Jacobs, Ross; Killilea, David W.; Lithgow, Gordon J.; Andersen, Julie K.

    2014-01-01

    Parkinson's disease (PD) is a debilitating motor and cognitive neurodegenerative disorder for which there is no cure. While aging is the major risk factor for developing PD, clear environmental risks have also been identified. Environmental exposure to the metal manganese (Mn) is a prominent risk factor for developing PD and occupational exposure to high levels of Mn can cause a syndrome known as manganism, which has symptoms that closely resemble PD. In this study, we developed a model of manganism in the environmentally tractable nematode, Caenorhabditis elegans. We find that, in addition to previously described modes of Mn toxicity, which primarily include mitochondrial dysfunction and oxidative stress, Mn exposure also significantly antagonizes protein homeostasis, another key pathological feature associated with PD and many age-related neurodegenerative diseases. Mn treatment activates the ER unfolded protein response, severely exacerbates toxicity in a disease model of protein misfolding, and alters aggregate solubility. Further, aged animals, which have previously been shown to exhibit decreased protein homeostasis, are particularly susceptible to Mn toxicity when compared to young animals, indicating the aging process sensitizes animals to metal toxicity. Mn exposure also significantly alters iron (Fe) and calcium (Ca) homeostasis, which are important for mitochondrial and ER health and which may further compound toxicity. These finding indicate that modeling manganism in C. elegans can provide a useful platform for identifying therapeutic interventions for ER stress, proteotoxicity, and age-dependent susceptibilities, key pathological features of PD and other related neurodegenerative diseases. PMID:25057947

  16. Lifespan extension by suppression of autophagy genes in Caenorhabditis elegans.

    Science.gov (United States)

    Hashimoto, Yasufumi; Ookuma, Sadatsugu; Nishida, Eisuke

    2009-06-01

    Lifespan is regulated by a complex combination of environmental and genetic factors. Autophagy, which is a bulk degradation system of macromolecules and organelles, has an important role in various biological events. In Caenorhabditis elegans, several autophagy genes have been shown to have a role in promoting longevity, but many other autophagy genes have not been examined for their role in the lifespan regulation. Here we have systematically examined the effect of RNAi suppression of 14 autophagy genes on lifespan. While maternal RNAi of autophagy genes in wild-type worms tended to reduce lifespan, maternal RNAi of each of seven autophagy genes in the insulin/IGF-1 receptor daf-2 mutants extended lifespan. Remarkably, RNAi of unc-51/atg-1, bec-1/atg-6 or atg-9, from young adult, i.e. after development, extended lifespan in both wild-type animals and daf-2 mutants, although RNAi of one or two genes shortened it. Moreover, our analysis suggests that the lifespan extension, which is induced by RNAi of unc-51, bec-1 or atg-9 after development, does not require the transcription factor daf-16, the NAD(+)-dependent protein deacetylase sir-2.1 or the genes related to mitochondrial functions. Collectively, our results suggest that autophagy may not always be beneficial to longevity, but may also function to restrict lifespan in C. elegans.

  17. Evaluation of the pathogenicity of Listeria spp. in Caenorhabditis elegans.

    Science.gov (United States)

    Forrester, Stacyann; Milillo, Sara Rose; Hoose, Wendy A; Wiedmann, Martin; Schwab, Ute

    2007-01-01

    Caenorhabditis has proven to be a useful model for studying host-pathogen interactions as well as the ability of nematodes to serve as vectors for the dispersal of foodborne pathogens. In this study, we evaluated whether C. elegans can serve as a host for Listeria spp. While there was an effect of growth media on C. elegans killing, C. elegans exposed to L. monocytogenes and L. innocua pregrown in Luria-Bertani medium showed reduced survival when compared to nonpathogenic E. coli OP50, while L. seeligeri showed survival similar to E. coli OP50. In a preference assay, C. elegans preferred E. coli over L. monocytogenes and L. innocua, but showed no preference between L. monocytogenes and L. innocua. A gentamicin assay indicated that L. monocytogenes did not persist within the C. elegans intestinal tract. Our findings that L. monocytogenes and L. innocua strains tested have equally deleterious effects on C. elegans and that L. monocytogenes did not establish intestinal infection conflict with other recently published results, which found intestinal infection and killing of C. elegans by L. monocytogenes. Further studies are thus needed to clarify the interactions between L. monocytogenes and C. elegans, including effects of environmental conditions and strain differences on killing and intestinal infection.

  18. 新秀丽线虫在筛选治疗神经退行性疾病药物中的运用%Caenorhabditis elegans:a promising model for antineurodegenerative diseases drug development

    Institute of Scientific and Technical Information of China (English)

    王言; 温志昌

    2011-01-01

    Lack of suitable drug sceening platform is the critical bottleneck in anti-neurodegenerative diseases drug development. Caenorhabditis elegans is a free-living, transparent nematode. Due to the short life and reproductive cycle, Caenorhabditis elegans is becoming a popular in vivo model for drug high throughput screenings. The aim of this review is to introduce the neurodegenerative diseases Caenorhabditis elegans models,and then discuss the related pharmacology study. Together we believe these models will play an important role in drug development.%缺乏合适的动物平台用于药物筛选一直是阻碍神经退行性疾病药物研发的主要因素.新秀丽线虫以其结构简单、体型小巧、生命周期短暂、繁殖迅速和易于培养的独特优势,成为可以适用于高通量药物筛选的在体动物模型.本文对与神经退行性疾病相关的新秀丽线虫模型进行了总结,并且讨论了利用该类模型进行的药理学研究,确定该类模型一定会在抗神经退行性疾病药物的研发中起到重要作用.

  19. The nematode Caenorhabditis elegans as a tool to predict chemical activity on mammalian development and identify mechanisms influencing toxicological outcome

    Science.gov (United States)

    Harlow, Philippa H.; Perry, Simon J.; Widdison, Stephanie; Daniels, Shannon; Bondo, Eddie; Lamberth, Clemens; Currie, Richard A.; Flemming, Anthony J.

    2016-01-01

    To determine whether a C. elegans bioassay could predict mammalian developmental activity, we selected diverse compounds known and known not to elicit such activity and measured their effect on C. elegans egg viability. 89% of compounds that reduced C. elegans egg viability also had mammalian developmental activity. Conversely only 25% of compounds found not to reduce egg viability in C. elegans were also inactive in mammals. We conclude that the C. elegans egg viability assay is an accurate positive predictor, but an inaccurate negative predictor, of mammalian developmental activity. We then evaluated C. elegans as a tool to identify mechanisms affecting toxicological outcomes among related compounds. The difference in developmental activity of structurally related fungicides in C. elegans correlated with their rate of metabolism. Knockdown of the cytochrome P450s cyp-35A3 and cyp-35A4 increased the toxicity to C. elegans of the least developmentally active compounds to the level of the most developmentally active. This indicated that these P450s were involved in the greater rate of metabolism of the less toxic of these compounds. We conclude that C. elegans based approaches can predict mammalian developmental activity and can yield plausible hypotheses for factors affecting the biological potency of compounds in mammals. PMID:26987796

  20. Prolonged manganese exposure induces severe deficits in lifespan,development and reproduction possibly by altering oxidative stress response in Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

    XIAO Jing; RUI Qi; GUO Yuling; CHANG Xingya; WANG Dayong

    2009-01-01

    We examined the possible multiple defects induced by acute and prolonged exposure to high levels of manganese (Mn) solution by monitoring the endpoints of lifespan,development,reproduction,and stress response.Our data suggest that acute exposure (6 h) to Mn did not cause severe defects of life span,development,and reproduction.Similarly,no significant defects could be found for the life span,development,and reproduction in animals exposed to a low concentration of Mn (2.5 μmol/L) for 48 h.In contrast,prolonged exposure (48-h) to high concentrations of Mn (75 and 200 μmol/L) resulted in significant defects of life span,development,and reproduction,as well as the increase of the percentage of population with hsp-16.2::gfp expression indicating the obvious induction of stress responses in exposed animals.Moreover,prolonged exposure (48-h) to high concentrations (75 and 200 μmol/L) of Mn decreased the expression levels of antioxidant genes of sod-1,sod-2,sod-3,and sod-4 compared to control.Therefore,prolonged exposure to high concentrations of Mn will induce the severe defects of life span,development,and reproduction in nematodes possibly by affecting the stress response and expression of antioxidant genes in Caenorhabditis elegans.

  1. Cadmium toxicity in the free-living nematode, Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Popham, J.D.; Webster, J.M.

    1979-10-01

    The effect of cadmium on the fecundity, growth, and fine structure of the free-living nematode Caenorhabditis elegans was studied. High concentrations of cadmium significantly decreased the fecundity and growth of these organisms. Electron microscopy showed that cadmium modifies the structure of the mitochondria in the esophagus and intestine, causes the formation of inclusion bodies in the nucleus of esophageal cells, and alters the morphology of cytosomes in the intestinal cells. The results suggest that the decreased fecundity and growth of cadmium-exposed C. elegans may be due to cadmium interfering with nutrient uptake or assimilation or both.

  2. Comparison of Caenorhabditis elegans NLP peptides with arthropod neuropeptides.

    Science.gov (United States)

    Husson, Steven J; Lindemans, Marleen; Janssen, Tom; Schoofs, Liliane

    2009-04-01

    Neuropeptides are small messenger molecules that can be found in all metazoans, where they govern a diverse array of physiological processes. Because neuropeptides seem to be conserved among pest species, selected peptides can be considered as attractive targets for drug discovery. Much can be learned from the model system Caenorhabditis elegans because of the availability of a sequenced genome and state-of-the-art postgenomic technologies that enable characterization of endogenous peptides derived from neuropeptide-like protein (NLP) precursors. Here, we provide an overview of the NLP peptide family in C. elegans and discuss their resemblance with arthropod neuropeptides and their relevance for anthelmintic discovery.

  3. The roles and acting mechanism of Caenorhabditis elegans DNase II genes in apoptotic dna degradation and development.

    Directory of Open Access Journals (Sweden)

    Huey-Jen Lai

    Full Text Available DNase II enzymes are acidic endonucleases that have been implicated in mediating apoptotic DNA degradation, a critical cell death execution event. C. elegans genome contains three DNase II homologues, NUC-1, CRN-6, and CRN-7, but their expression patterns, acting sites, and roles in apoptotic DNA degradation and development are unclear. We have conducted a comprehensive analysis of three C. elegans DNase II genes and found that nuc-1 plays a major role, crn-6 plays an auxiliary role, and crn-7 plays a negligible role in resolving 3' OH DNA breaks generated in apoptotic cells. Promoter swapping experiments suggest that crn-6 but not crn-7 can partially substitute for nuc-1 in mediating apoptotic DNA degradation and both fail to replace nuc-1 in degrading bacterial DNA in intestine. Despite of their restricted and largely non-overlapping expression patterns, both CRN-6 and NUC-1 can mediate apoptotic DNA degradation in many cells, suggesting that they are likely secreted nucleases that are retaken up by other cells to exert DNA degradation functions. Removal or disruption of NUC-1 secretion signal eliminates NUC-1's ability to mediate DNA degradation across its expression border. Furthermore, blocking cell corpse engulfment does not affect apoptotic DNA degradation mediated by nuc-1, suggesting that NUC-1 acts in apoptotic cells rather than in phagocytes to resolve 3' OH DNA breaks. Our study illustrates how multiple DNase II nucleases play differential roles in apoptotic DNA degradation and development and reveals an unexpected mode of DNase II action in mediating DNA degradation.

  4. The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry.

    Science.gov (United States)

    Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

    2016-01-01

    Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling.

  5. Tissue-specific regulation of the LIM homeobox gene lin-11 during development of the Caenorhabditis elegans egg-laying system.

    Science.gov (United States)

    Gupta, Bhagwati P; Sternberg, Paul W

    2002-07-01

    The egg-laying system of Caenorhabditis elegans hermaphrodites requires development of the vulva and its precise connection with the uterus. This process is regulated by LET-23-mediated epidermal growth factor signaling and LIN-12-mediated lateral signaling pathways. Among the nuclear factors that act downstream of these pathways, the LIM homeobox gene lin-11 plays a major role. lin-11 mutant animals are egg-laying defective because of the abnormalities in vulval lineage and uterine seam-cell formation. However, the mechanisms providing specificity to lin-11 function are not understood. Here, we examine the regulation of lin-11 during development of the egg-laying system. Our results demonstrate that the tissue-specific expression of lin-11 is controlled by two distinct regulatory elements that function as independent modules and together specify a wild-type egg-laying system. A uterine pi lineage module depends on the LIN-12/Notch signaling, while a vulval module depends on the LIN-17-mediated Wnt signaling. These results provide a unique example of the tissue-specific regulation of a LIM homeobox gene by two evolutionarily conserved signaling pathways. Finally, we provide evidence that the regulation of lin-11 by LIN-12/Notch signaling is directly mediated by the Su(H)/CBF1 family member LAG-1.

  6. Development and evaluation of an in vivo assay in Caenorhabditis elegans for screening of compounds for their effect on cytochrome P450 expression

    Indian Academy of Sciences (India)

    Baby P S Chakrapani; Sandeep Kumar; Jamuna R Subramaniam

    2008-06-01

    Most drugs and xenobiotics induce the expression of cytochrome P450 (CYP) enzymes, which reduce the bioavailability of the inducer and/or co-administered drugs. Therefore, evaluation of new drug candidates for their effect on CYP expression is an essential step in drug development. The available methods for this purpose are expensive and not amenable to high-throughput screening. We developed a fluorescence-based in vivo assay using transgenic Caenorhabditis elegans worms that express the green fluorescent protein (GFP) under the control of various CYP promoters. Using this assay, we found striking similarities between the worm CYPs and their human orthologs in their response to treatment with various drugs. For example, the antibiotic rifampicin, one of the strongest inducers of the human gene CYP3A4, was the strongest inducer of the worm ortholog CYP13A7. Since worms can be easily grown in liquid medium in microtitre plates, the assay described in this paper is suitable for the screening of a large number of potential lead compounds in the drug discovery process.

  7. Dietary Supplementation of Polyunsaturated Fatty Acids in Caenorhabditis elegans

    OpenAIRE

    Deline, Marshall L.; Vrablik, Tracy L.; Watts, Jennifer L.

    2013-01-01

    Fatty acids are essential for numerous cellular functions. They serve as efficient energy storage molecules, make up the hydrophobic core of membranes, and participate in various signaling pathways. Caenorhabditis elegans synthesizes all of the enzymes necessary to produce a range of omega-6 and omega-3 fatty acids. This, combined with the simple anatomy and range of available genetic tools, make it an attractive model to study fatty acid function. In order to investigate the genetic pathways...

  8. Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning

    OpenAIRE

    Gallagher, Larry A.; Manoil, Colin

    2001-01-01

    In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aeruginosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnC) eliminated ne...

  9. Metabolite induction of Caenorhabditis elegans dauer larvae arises via transport in the pharynx.

    Science.gov (United States)

    Baiga, Thomas J; Guo, Haibing; Xing, Yalan; O'Doherty, George A; Dillin, Andrew; Austin, Michael B; Noel, Joseph P; La Clair, James J

    2008-05-16

    Caenorhabditis elegans sense natural chemicals in their environment and use them as cues to regulate their development. This investigation probes the mechanism of sensory trafficking by evaluating the processing of fluorescent derivatives of natural products in C. elegans. Fluorescent analogs of daumone, an ascaroside, and apigenin were prepared by total synthesis and evaluated for their ability to induce entry into a nonaging dauer state. Fluorescent imaging detailed the uptake and localization of every labeled compound at each stage of the C. elegans life cycle. Comparative analyses against natural products that did not induce dauer indicated that dauer-triggering natural products accumulated in the cuticle of the pharnyx. Subsequent transport of these molecules to amphid neurons signaled entry into the dauer state. These studies provide cogent evidence supporting the roles of the glycosylated fatty acid daumone and related ascarosides and the ubiquitous plant flavone apigenin as chemical cues regulating C. elegans development.

  10. Isolating genes involved with genotoxic drug response in the nematode Caenorhabditis elegans using genome-wide RNAi screening

    DEFF Research Database (Denmark)

    Schøler, Lone Vedel; Møller, Tine Hørning; Nørgaard, Steffen;

    2012-01-01

    The soil nematode Caenorhabditis elegans has become a popular genetic model organism used to study a broad range of complex biological processes, including development, aging, apoptosis, and DNA damage responses. Many genetic tools and tricks have been developed in C. elegans including knock down...... of gene expression via RNA interference (RNAi). In C. elegans RNAi can effectively be administrated via feeding the nematodes bacteria expressing double-stranded RNA targeting the gene of interest. Several commercial C. elegans RNAi libraries are available and hence gene inactivation using RNAi can...

  11. Chemically defined medium and Caenorhabditis elegans

    Science.gov (United States)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  12. The versatile worm: genetic and genomic resources for Caenorhabditis elegans research.

    Science.gov (United States)

    Antoshechkin, Igor; Sternberg, Paul W

    2007-07-01

    Since its establishment as a model organism, Caenorhabditis elegans has been an invaluable tool for biological research. An immense spectrum of questions can be addressed using this small nematode, making it one of the most versatile and exciting model organisms. Although the many tools and resources developed by the C. elegans community greatly facilitate new discoveries, they can also overwhelm newcomers to the field. This Review aims to familiarize new worm researchers with the main resources, and help them to select the tools that are best suited for their needs. We also hope that it will be helpful in identifying new research opportunities and will promote the development of additional resources.

  13. Caenorhabditis elegans responses to bacteria from its natural habitats

    Science.gov (United States)

    Rowedder, Holli; Braendle, Christian; Félix, Marie-Anne; Ruvkun, Gary

    2016-01-01

    Most Caenorhabditis elegans studies have used laboratory Escherichia coli as diet and microbial environment. Here we characterize bacteria of C. elegans' natural habitats of rotting fruits and vegetation to provide greater context for its physiological responses. By the use of 16S ribosomal DNA (rDNA)-based sequencing, we identified a large variety of bacteria in C. elegans habitats, with phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria being most abundant. From laboratory assays using isolated natural bacteria, C. elegans is able to forage on most bacteria (robust growth on ∼80% of >550 isolates), although ∼20% also impaired growth and arrested and/or stressed animals. Bacterial community composition can predict wild C. elegans population states in both rotting apples and reconstructed microbiomes: alpha-Proteobacteria-rich communities promote proliferation, whereas Bacteroidetes or pathogens correlate with nonproliferating dauers. Combinatorial mixtures of detrimental and beneficial bacteria indicate that bacterial influence is not simply nutritional. Together, these studies provide a foundation for interrogating how bacteria naturally influence C. elegans physiology. PMID:27317746

  14. Use of the induced gene-expression in the soil nematode Caenorhabditis elegans as a biomonitor; Nutzung der induzierbaren Genexpression des Nematoden Caenorhabditis elegans als Biomonitor

    Energy Technology Data Exchange (ETDEWEB)

    Menzel, R.; Reichert, K.; Achazi, R. [Freie Univ. Berlin (Germany). Inst. fuer Biologie - Oekotoxikologie und Biochemie

    2002-07-01

    The soil nematode Caenorhabditis elegans is one of the simplest animals having the status of a laboratory model. Its already completely sequenced genome contains the remarkable number of 80 cytochrome P450 genes (CYP) and many further genes coding for enzymes involved in biotransformation. In order to study xenobiotically induced gene expression in C. elegans, liquid cultures were exposed to different, well-known xenobiotic inducers. The mRNA expression was detected by two different types of DNA arrays and semi-quantitative RT-PCR. {beta}-naphthoflavone, PCB52 and lansoprazol were the most active and, in particular, induced almost all CYP35 isoforms strongly. In conclusion, the xenobiotic dependent gene expression of C. elegans is a useful tool to reveal defense mechanisms against potential damaging substances as well as for developing a biomonitoring system. (orig.) [German] Der Bodennematode Caenorhabditis elegans gilt als das einfachste mehrzellige Tier mit dem Status eines Labormodels. Basierend auf seinem entschluesselten Genom konnte die bemerkenswerte Zahl von 80 Cytochrom P450 Genen (CYP) und eine Vielzahl weiterer Gene, welche fuer Enzyme der Biotransformation kodieren, identifiziert werden. Die differentielle Genexpression von C. elegans nach Schadstoffzugabe wurde in Fluessigkulturen mit 18 Xenobiotika aus unterschiedlichen Schadstoffgruppen untersucht. Anschliessend wurde die mRNA Expression mit DNA Arrays und semi-quantitativer RT-PCR bestimmt. {beta}-Naphthoflavone, PCB52 and Lansoprazol erwiesen sich dabei als die wirksamsten Induktoren und konnten unter anderen alle CYP 35 Isoformen stark induzieren. Mit diesen Untersuchungen konnte gezeigt werden, dass die schadstoffinduzierte Genexpression in C. elegans ein adaequates System ist, um sowohl Detoxifikationsmechanismen zu untersuchen als auch ein Biomonitorscreening aufzubauen. (orig.)

  15. Live-cell imaging of mitosis in Caenorhabditis elegans embryos.

    Science.gov (United States)

    Powers, James A

    2010-06-01

    Caenorhabditis elegans is a wonderful model system for live imaging studies of mitosis. A huge collection of research tools is readily available to facilitate experimentation. For imaging, C. elegans embryos provide large clear cells, an invariant pattern of cell division, only six chromosomes, a very short cell cycle, and remain healthy and happy at room temperature. Mitosis is a complicated process and the types of research questions being asked about the mechanisms involved are continuously expanding. For each experiment, the details of imaging methods need to be tailored to the question. Specific imaging methods will depend on the microscopy hardware and software available to each researcher. This article presents points to consider when choosing a microscope, designing an imaging experiment, or selecting appropriate worm strains for imaging. A method for mounting C. elegans embryos and guidelines for fluorescence and differential interference contrast imaging of mitosis in live embryos are presented.

  16. The effects of short-term hypergravity on Caenorhabditis elegans

    Science.gov (United States)

    Saldanha, Jenifer N.; Pandey, Santosh; Powell-Coffman, Jo Anne

    2016-08-01

    As we seek to recognize the opportunities of advanced aerospace technologies and spaceflight, it is increasingly important to understand the impacts of hypergravity, defined as gravitational forces greater than those present on the earth's surface. The nematode Caenorhabditis elegans has been established as a powerful model to study the effects of altered gravity regimens and has displayed remarkable resilience to space travel. In this study, we investigate the effects of short-term and defined hypergravity exposure on C. elegans motility, brood size, pharyngeal pumping rates, and lifespan. The results from this study advance our understanding of the effects of shorter durations of exposure to increased gravitational forces on C. elegans, and also contribute to the growing body of literature on the impacts of altered gravity regimens on earth's life forms.

  17. Transfer characteristics of a thermosensory synapse in Caenorhabditis elegans.

    Science.gov (United States)

    Narayan, Anusha; Laurent, Gilles; Sternberg, Paul W

    2011-06-07

    Caenorhabditis elegans is a compact, attractive system for neural circuit analysis. An understanding of the functional dynamics of neural computation requires physiological analyses. We undertook the characterization of transfer at a central synapse in C. elegans by combining optical stimulation of targeted neurons with electrophysiological recordings. We show that the synapse between AFD and AIY, the first stage in the thermotactic circuit, exhibits excitatory, tonic, and graded release. We measured the linear range of the input-output curve and estimate the static synaptic gain as 0.056 (<0.1). Release showed no obvious facilitation or depression. Transmission at this synapse is peptidergic. The AFD/AIY synapse thus seems to have evolved for reliable transmission of a scaled-down temperature signal from AFD, enabling AIY to monitor and integrate temperature with other sensory input. Combining optogenetics with electrophysiology is a powerful way to analyze C. elegans' neural function.

  18. Guidelines for monitoring autophagy in Caenorhabditis elegans.

    Science.gov (United States)

    Zhang, Hong; Chang, Jessica T; Guo, Bin; Hansen, Malene; Jia, Kailiang; Kovács, Attila L; Kumsta, Caroline; Lapierre, Louis R; Legouis, Renaud; Lin, Long; Lu, Qun; Meléndez, Alicia; O'Rourke, Eyleen J; Sato, Ken; Sato, Miyuki; Wang, Xiaochen; Wu, Fan

    2015-01-01

    The cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A combination of measuring levels of the lipidated Atg8 ortholog LGG-1, degradation of well-characterized autophagic substrates such as germline P granule components and the SQSTM1/p62 ortholog SQST-1, expression of autophagic genes and electron microscopy analysis of autophagic structures are presently the most informative, yet steady-state, approaches available to assess autophagy levels in C. elegans. We also review how altered autophagy activity affects a variety of biological processes in C. elegans such as L1 survival under starvation conditions, dauer formation, aging, and cell death, as well as neuronal cell specification. Taken together, C. elegans is emerging as a powerful model organism to monitor autophagy while evaluating important physiological roles for autophagy in key developmental events as well as during adulthood.

  19. Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.

    Directory of Open Access Journals (Sweden)

    Read Pukkila-Worley

    2011-06-01

    Full Text Available Candida albicans yeast cells are found in the intestine of most humans, yet this opportunist can invade host tissues and cause life-threatening infections in susceptible individuals. To better understand the host factors that underlie susceptibility to candidiasis, we developed a new model to study antifungal innate immunity. We demonstrate that the yeast form of C. albicans establishes an intestinal infection in Caenorhabditis elegans, whereas heat-killed yeast are avirulent. Genome-wide, transcription-profiling analysis of C. elegans infected with C. albicans yeast showed that exposure to C. albicans stimulated a rapid host response involving 313 genes (124 upregulated and 189 downregulated, ~1.6% of the genome many of which encode antimicrobial, secreted or detoxification proteins. Interestingly, the host genes affected by C. albicans exposure overlapped only to a small extent with the distinct transcriptional responses to the pathogenic bacteria Pseudomonas aeruginosa or Staphylococcus aureus, indicating that there is a high degree of immune specificity toward different bacterial species and C. albicans. Furthermore, genes induced by P. aeruginosa and S. aureus were strongly over-represented among the genes downregulated during C. albicans infection, suggesting that in response to fungal pathogens, nematodes selectively repress the transcription of antibacterial immune effectors. A similar phenomenon is well known in the plant immune response, but has not been described previously in metazoans. Finally, 56% of the genes induced by live C. albicans were also upregulated by heat-killed yeast. These data suggest that a large part of the transcriptional response to C. albicans is mediated through "pattern recognition," an ancient immune surveillance mechanism able to detect conserved microbial molecules (so-called pathogen-associated molecular patterns or PAMPs. This study provides new information on the evolution and regulation of the innate

  20. Regulation of Axon Guidance during Neuronal Development in Caenorhabditis elegans%线虫C.elegans神经发育中轴突引导的调控机制

    Institute of Scientific and Technical Information of China (English)

    郑一春; 罗建红

    1999-01-01

    @@ 美丽小杆线虫(Caenorhabditis elegans)是一种微小的土壤线虫[1],自胚胎发育成1mm长的成虫只需三天,结构简单,雌雄同体,由959个体细胞构成.但这959个体细胞分化出了各种主要的组织类型,包括肌肉、神经元、肠道、上皮等.

  1. Gene expression markers for Caenorhabditis elegans vulval cells.

    Science.gov (United States)

    Inoue, Takao; Sherwood, David R; Aspöck, Gudrun; Butler, James A; Gupta, Bhagwati P; Kirouac, Martha; Wang, Minqin; Lee, Pei-Yun; Kramer, James M; Hope, Ian; Bürglin, Thomas R; Sternberg, Paul W

    2002-12-01

    The analysis of cell fate patterning during the vulval development of Caenorhabditis elegans has relied mostly on the direct observation of cell divisions and cell movements (cell lineage analysis). However, reconstruction of the developing vulva from EM serial sections has suggested seven different cell types (vulA, vulB1, vulB2, vulC, vulD, vulE, and vulF), many of which cannot be distinguished based on such observations. Here we report the vulval expression of seven genes, egl-17, cdh-3, ceh-2, zmp-1, B0034.1, T04B2.6 and F47B8.6 based on gfp, cfp and yfp (green fluorescent protein and color variants) reporter fusions. Each gene expresses in a specific subset of vulval cells, and is therefore useful as a marker for vulval cell fates. Together, expressions of markers distinguish six cell types, and reveal a strict temporal control of gene expression in the developing vulva.

  2. Bacterial attraction and quorum sensing inhibition in Caenorhabditis elegans exudates.

    Science.gov (United States)

    Kaplan, Fatma; Badri, Dayakar V; Zachariah, Cherian; Ajredini, Ramadan; Sandoval, Francisco J; Roje, Sanja; Levine, Lanfang H; Zhang, Fengli; Robinette, Steven L; Alborn, Hans T; Zhao, Wei; Stadler, Michael; Nimalendran, Rathika; Dossey, Aaron T; Brüschweiler, Rafael; Vivanco, Jorge M; Edison, Arthur S

    2009-08-01

    Caenorhabditis elegans, a bacterivorous nematode, lives in complex rotting fruit, soil, and compost environments, and chemical interactions are required for mating, monitoring population density, recognition of food, avoidance of pathogenic microbes, and other essential ecological functions. Despite being one of the best-studied model organisms in biology, relatively little is known about the signals that C. elegans uses to interact chemically with its environment or as defense. C. elegans exudates were analyzed by using several analytical methods and found to contain 36 common metabolites that include organic acids, amino acids, and sugars, all in relatively high abundance. Furthermore, the concentrations of amino acids in the exudates were dependent on developmental stage. The C. elegans exudates were tested for bacterial chemotaxis using Pseudomonas putida (KT2440), a plant growth promoting rhizobacterium, Pseudomonas aeruginosa (PAO1), a soil bacterium pathogenic to C. elegans, and Escherichia coli (OP50), a non-motile bacterium tested as a control. The C. elegans exudates attracted the two Pseudomonas species, but had no detectable antibacterial activity against P. aeruginosa. To our surprise, the exudates of young adult and adult life stages of C. elegans exudates inhibited quorum sensing in the reporter system based on the LuxR bacterial quorum sensing (QS) system, which regulates bacterial virulence and other factors in Vibrio fischeri. We were able to fractionate the QS inhibition and bacterial chemotaxis activities, thus demonstrating that these activities are chemically distinct. Our results demonstrate that C. elegans can attract its bacterial food and has the potential of partially regulating the virulence of bacterial pathogens by inhibiting specific QS systems.

  3. Apoptosis maintains oocyte quality in aging Caenorhabditis elegans females.

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    Sara Andux

    2008-12-01

    Full Text Available In women, oocytes arrest development at the end of prophase of meiosis I and remain quiescent for years. Over time, the quality and quantity of these oocytes decreases, resulting in fewer pregnancies and an increased occurrence of birth defects. We used the nematode Caenorhabditis elegans to study how oocyte quality is regulated during aging. To assay quality, we determine the fraction of oocytes that produce viable eggs after fertilization. Our results show that oocyte quality declines in aging nematodes, as in humans. This decline affects oocytes arrested in late prophase, waiting for a signal to mature, and also oocytes that develop later in life. Furthermore, mutations that block all cell deaths result in a severe, early decline in oocyte quality, and this effect increases with age. However, mutations that block only somatic cell deaths or DNA-damage-induced deaths do not lower oocyte quality. Two lines of evidence imply that most developmentally programmed germ cell deaths promote the proper allocation of resources among oocytes, rather than eliminate oocytes with damaged chromosomes. First, oocyte quality is lowered by mutations that do not prevent germ cell deaths but do block the engulfment and recycling of cell corpses. Second, the decrease in quality caused by apoptosis mutants is mirrored by a decrease in the size of many mature oocytes. We conclude that competition for resources is a serious problem in aging germ lines, and that apoptosis helps alleviate this problem.

  4. Epidermal growth factor signaling induces behavioral quiescence in Caenorhabditis elegans.

    Science.gov (United States)

    Van Buskirk, Cheryl; Sternberg, Paul W

    2007-10-01

    The epidermal growth factor receptor (EGFR)/ErbB receptor tyrosine kinases regulate several aspects of development, including the development of the mammalian nervous system. ErbB signaling also has physiological effects on neuronal function, with influences on synaptic plasticity and daily cycles of activity. However, little is known about the effectors of EGFR activation in neurons. Here we show that EGF signaling has a nondevelopmental effect on behavior in Caenorhabditis elegans. Ectopic expression of the EGF-like ligand LIN-3 at any stage induces a reversible cessation of feeding and locomotion. These effects are mediated by neuronal EGFR (also called LET-23) and phospholipase C-gamma (PLC-gamma), diacylglycerol-binding proteins, and regulators of synaptic vesicle release. Activation of EGFR within a single neuron, ALA, is sufficient to induce a quiescent state. This pathway modulates the cessation of pharyngeal pumping and locomotion that normally occurs during the lethargus period that precedes larval molting. Our results reveal an evolutionarily conserved role for EGF signaling in the regulation of behavioral quiescence.

  5. Functional transcriptomics of a migrating cell in Caenorhabditis elegans.

    Science.gov (United States)

    Schwarz, Erich M; Kato, Mihoko; Sternberg, Paul W

    2012-10-02

    In both metazoan development and metastatic cancer, migrating cells must carry out a detailed, complex program of sensing cues, binding substrates, and moving their cytoskeletons. The linker cell in Caenorhabditis elegans males undergoes a stereotyped migration that guides gonad organogenesis, occurs with precise timing, and requires the nuclear hormone receptor NHR-67. To better understand how this occurs, we performed RNA-seq of individually staged and dissected linker cells, comparing transcriptomes from linker cells of third-stage (L3) larvae, fourth-stage (L4) larvae, and nhr-67-RNAi-treated L4 larvae. We observed expression of 8,000-10,000 genes in the linker cell, 22-25% of which were up- or down-regulated 20-fold during development by NHR-67. Of genes that we tested by RNAi, 22% (45 of 204) were required for normal shape and migration, suggesting that many NHR-67-dependent, linker cell-enriched genes play roles in this migration. One unexpected class of genes up-regulated by NHR-67 was tandem pore potassium channels, which are required for normal linker-cell migration. We also found phenotypes for genes with human orthologs but no previously described migratory function. Our results provide an extensive catalog of genes that act in a migrating cell, identify unique molecular functions involved in nematode cell migration, and suggest similar functions in humans.

  6. Targeted Metabolomics Reveals a Male Pheromone and Sex-Specific Ascaroside Biosynthesis in Caenorhabditis elegans

    OpenAIRE

    Izrayelit, Yevgeniy; Srinivasan, Jagan; Campbell, Sydney L.; Jo, Yeara; von Reuss, Stephan H.; Genoff, Margaux-C; Paul W. Sternberg; Schroeder, Frank C.

    2012-01-01

    In the model organism Caenorhabditis elegans, a class of small molecule signals called ascarosides regulate development, mating, and social behaviors. Ascaroside production has been studied in the predominant sex, the hermaphrodite, but not in males, which account for less than 1% of wild-type worms grown under typical laboratory conditions. Using HPLC–MS-based targeted metabolomics, we show that males also produce ascarosides and that their ascaroside profile differs markedly from that of he...

  7. Radiation-induced genomic instability in Caenorhabditis elegans.

    Science.gov (United States)

    Huumonen, Katriina; Immonen, Hanna-Kaisa; Baverstock, Keith; Hiltunen, Mikko; Korkalainen, Merja; Lahtinen, Tapani; Parviainen, Juha; Viluksela, Matti; Wong, Garry; Naarala, Jonne; Juutilainen, Jukka

    2012-10-01

    Radiation-induced genomic instability has been well documented, particularly in vitro. However, the understanding of its mechanisms and their consequences in vivo is still limited. In this study, Caenorhabditis elegans (C. elegans; strain CB665) nematodes were exposed to X-rays at doses of 0.1, 1, 3 or 10Gy. The endpoints were measured several generations after exposure and included mutations in the movement-related gene unc-58, alterations in gene expression analysed with oligoarrays containing the entire C. elegans genome, and micro-satellite mutations measured by capillary electrophoresis. The progeny of the irradiated nematodes showed an increased mutation frequency in the unc-58 gene, with a maximum response observed at 1Gy. Significant differences were also found in gene expression between the irradiated (1Gy) and non-irradiated nematode lines. Differences in gene expression did not show clear clustering into certain gene categories, suggesting that the instability might be a chaotic process rather than a result of changes in the function of few specific genes such as, e.g., those responsible for DNA repair. Increased heterogeneity in gene expression, which has previously been described in irradiated cultured human lymphocytes, was also observed in the present study in C. elegans, the coefficient of variation of gene expression being higher in the progeny of irradiated nematodes than in control nematodes. To the best of our knowledge, this is the first publication reporting radiation-induced genomic instability in C. elegans.

  8. Caenorhabditis elegans swimming in a saturated particulate system

    Science.gov (United States)

    Jung, Sunghwan

    2010-03-01

    Caenorhabditis elegans (C. elegans) is a nematode that often swims in saturated soil in nature. We investigated the locomotive behavior of C. elegans swimming in a fluid with particles of various sizes and found that the nematode swims a greater distance per undulation than it does in a fluid without particles. The Strouhal number (a ratio of lateral to forward velocity) of C. elegans significantly decreases in a saturated particulate medium (0.50±0.13) in comparison to a fluid without particles (1.6±0.27). This result was unexpected due to the generally low performance of a body moving in a high drag medium. In our model, a saturated granular system is approximated as a porous medium where only the hydrodynamic forces on the body are considered. Combining these assumptions with resistive force theory, we find that a porous medium provides more asymmetric drag on a slender body, and consequently that C. elegans locomotes with a greater distance per undulation.

  9. TILLING is an effective reverse genetics technique for Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Zetka Monique C

    2006-10-01

    Full Text Available Abstract Background TILLING (Targeting Induced Local Lesions in Genomes is a reverse genetic technique based on the use of a mismatch-specific enzyme that identifies mutations in a target gene through heteroduplex analysis. We tested this technique in Caenorhabditis elegans, a model organism in which genomics tools have been well developed, but limitations in reverse genetics have restricted the number of heritable mutations that have been identified. Results To determine whether TILLING represents an effective reverse genetic strategy for C. elegans we generated an EMS-mutagenised population of approximately 1500 individuals and screened for mutations in 10 genes. A total of 71 mutations were identified by TILLING, providing multiple mutant alleles for every gene tested. Some of the mutations identified are predicted to be silent, either because they are in non-coding DNA or because they affect the third bp of a codon which does not change the amino acid encoded by that codon. However, 59% of the mutations identified are missense alleles resulting in a change in one of the amino acids in the protein product of the gene, and 3% are putative null alleles which are predicted to eliminate gene function. We compared the types of mutation identified by TILLING with those previously reported from forward EMS screens and found that 96% of TILLING mutations were G/C-to-A/T transitions, a rate significantly higher than that found in forward genetic screens where transversions and deletions were also observed. The mutation rate we achieved was 1/293 kb, which is comparable to the mutation rate observed for TILLING in other organisms. Conclusion We conclude that TILLING is an effective and cost-efficient reverse genetics tool in C. elegans. It complements other reverse genetic techniques in this organism, can provide an allelic series of mutations for any locus and does not appear to have any bias in terms of gene size or location. For eight of the 10

  10. Intracellular Assessment of ATP Levels in Caenorhabditis elegans

    Science.gov (United States)

    Palikaras, Konstantinos; Tavernarakis, Nektarios

    2017-01-01

    Eukaryotic cells heavily depend on adenosine triphosphate (ATP) generated by oxidative phosphorylation (OXPHOS) within mitochondria. ATP is the major energy currency molecule, which fuels cell to carry out numerous processes, including growth, differentiation, transportation and cell death among others (Khakh and Burnstock, 2009). Therefore, ATP levels can serve as a metabolic gauge for cellular homeostasis and survival (Artal-Sanz and Tavernarakis, 2009; Gomes et al., 2011; Palikaras et al., 2015). In this protocol, we describe a method for the determination of intracellular ATP levels using a bioluminescence approach in the nematode Caenorhabditis elegans. PMID:28194429

  11. An elegant mind: learning and memory in Caenorhabditis elegans.

    Science.gov (United States)

    Ardiel, Evan L; Rankin, Catharine H

    2010-04-01

    This article reviews the literature on learning and memory in the soil-dwelling nematode Caenorhabditis elegans. Paradigms include nonassociative learning, associative learning, and imprinting, as worms have been shown to habituate to mechanical and chemical stimuli, as well as learn the smells, tastes, temperatures, and oxygen levels that predict aversive chemicals or the presence or absence of food. In each case, the neural circuit underlying the behavior has been at least partially described, and forward and reverse genetics are being used to elucidate the underlying cellular and molecular mechanisms. Several genes have been identified with no known role other than mediating behavior plasticity.

  12. Dietary and microbiome factors determine longevity in Caenorhabditis elegans

    Science.gov (United States)

    Sánchez-Blanco, Adolfo; Rodríguez-Matellán, Alberto; González-Paramás, Ana; González-Manzano, Susana; Kim, Stuart K.; Mollinedo, Faustino

    2016-01-01

    Diet composition affects organismal health. Nutrient uptake depends on the microbiome. Caenorhabditis elegans fed a Bacillus subtilis diet live longer than those fed the standard Escherichia coli diet. Here we report that this longevity difference is primarily caused by dietary coQ, an antioxidant synthesized by E. coli but not by B. subtilis. CoQ-supplemented E. coli fed worms have a lower oxidation state yet live shorter than coQ-less B. subtilis fed worms. We showed that mutations affecting longevity for E. coli fed worms do not always lead to similar effects when worms are fed B. subtilis. We propose that coQ supplementation by the E. coli diet alters the worm cellular REDOX homeostasis, thus decreasing longevity. Our results highlight the importance of microbiome factors in longevity, argue that antioxidant supplementation can be detrimental, and suggest that the C. elegans standard E. coli diet can alter the effect of signaling pathways on longevity. PMID:27510225

  13. X-ray inactivation of Caenorhabditis elegans embryos or larvae

    Energy Technology Data Exchange (ETDEWEB)

    Ishi, N.; Suzuki, K. (Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine)

    1990-11-01

    The lethal effects of X-irradiation were examined in staged populations of Caenorhabditis elegans embryos or larvae. Radiation resistance decreased slightly throughout the first, proliferative phase of embryogenesis. This might be due to the increase in target size, since most cells in C. elegans are autonomously determined. Animals irradiated in the second half of embryogenesis were about 40-fold more resistant to the lethal effects of X-rays. This is probably due to the absence of cell divisions during this time. The radiation resistance increased still more with advancing larval stages. A radiation hypersensitive mutant, rad-1, irradiated in the first half of embryogenesis, is about 30-fold more sensitive than wild-type, but in the second half it is the same as wild-type. (author).

  14. Measuring Food Intake and Nutrient Absorption in Caenorhabditis elegans.

    Science.gov (United States)

    Gomez-Amaro, Rafael L; Valentine, Elizabeth R; Carretero, Maria; LeBoeuf, Sarah E; Rangaraju, Sunitha; Broaddus, Caroline D; Solis, Gregory M; Williamson, James R; Petrascheck, Michael

    2015-06-01

    Caenorhabditis elegans has emerged as a powerful model to study the genetics of feeding, food-related behaviors, and metabolism. Despite the many advantages of C. elegans as a model organism, direct measurement of its bacterial food intake remains challenging. Here, we describe two complementary methods that measure the food intake of C. elegans. The first method is a microtiter plate-based bacterial clearing assay that measures food intake by quantifying the change in the optical density of bacteria over time. The second method, termed pulse feeding, measures the absorption of food by tracking de novo protein synthesis using a novel metabolic pulse-labeling strategy. Using the bacterial clearance assay, we compare the bacterial food intake of various C. elegans strains and show that long-lived eat mutants eat substantially more than previous estimates. To demonstrate the applicability of the pulse-feeding assay, we compare the assimilation of food for two C. elegans strains in response to serotonin. We show that serotonin-increased feeding leads to increased protein synthesis in a SER-7-dependent manner, including proteins known to promote aging. Protein content in the food has recently emerged as critical factor in determining how food composition affects aging and health. The pulse-feeding assay, by measuring de novo protein synthesis, represents an ideal method to unequivocally establish how the composition of food dictates protein synthesis. In combination, these two assays provide new and powerful tools for C. elegans research to investigate feeding and how food intake affects the proteome and thus the physiology and health of an organism.

  15. Staphylococcal biofilm exopolysaccharide protects against Caenorhabditis elegans immune defenses.

    Directory of Open Access Journals (Sweden)

    Jakob Begun

    2007-04-01

    Full Text Available Staphylococcus epidermidis and Staphylococcus aureus are leading causes of hospital-acquired infections that have become increasingly difficult to treat due to the prevalence of antibiotic resistance in these organisms. The ability of staphylococci to produce biofilm is an important virulence mechanism that allows bacteria both to adhere to living and artificial surfaces and to resist host immune factors and antibiotics. Here, we show that the icaADBC locus, which synthesizes the biofilm-associated polysaccharide intercellular adhesin (PIA in staphylococci, is required for the formation of a lethal S. epidermidis infection in the intestine of the model nematode Caenorhabditis elegans. Susceptibility to S. epidermidis infection is influenced by mutation of the C. elegans PMK-1 p38 mitogen-activated protein (MAP kinase or DAF-2 insulin-signaling pathways. Loss of PIA production abrogates nematocidal activity and leads to reduced bacterial accumulation in the C. elegans intestine, while overexpression of the icaADBC locus in S. aureus augments virulence towards nematodes. PIA-producing S. epidermidis has a significant survival advantage over ica-deficient S. epidermidis within the intestinal tract of wild-type C. elegans, but not in immunocompromised nematodes harboring a loss-of-function mutation in the p38 MAP kinase pathway gene sek-1. Moreover, sek-1 and pmk-1 mutants are equally sensitive to wild-type and icaADBC-deficient S. epidermidis. These results suggest that biofilm exopolysaccharide enhances virulence by playing an immunoprotective role during colonization of the C. elegans intestine. These studies demonstrate that C. elegans can serve as a simple animal model for studying host-pathogen interactions involving staphylococcal biofilm exopolysaccharide and suggest that the protective activity of biofilm matrix represents an ancient conserved function for resisting predation.

  16. trt-1 is the Caenorhabditis elegans catalytic subunit of telomerase.

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    Bettina Meier

    2006-02-01

    Full Text Available Mutants of trt-1, the Caenorhabditis elegans telomerase reverse transcriptase, reproduce normally for several generations but eventually become sterile as a consequence of telomere erosion and end-to-end chromosome fusions. Telomere erosion and uncapping do not cause an increase in apoptosis in the germlines of trt-1 mutants. Instead, late-generation trt-1 mutants display chromosome segregation defects that are likely to be the direct cause of sterility. trt-1 functions in the same telomere replication pathway as mrt-2, a component of the Rad9/Rad1/Hus1 (9-1-1 proliferating cell nuclear antigen-like sliding clamp. Thus, the 9-1-1 complex may be required for telomerase to act at chromosome ends in C. elegans. Although telomere erosion limits replicative life span in human somatic cells, neither trt-1 nor telomere shortening affects postmitotic aging in C. elegans. These findings illustrate effects of telomere dysfunction in C. elegans mutants lacking the catalytic subunit of telomerase, trt-1.

  17. Allyl isothiocyanate induced stress response in Caenorhabditis elegans

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    Saini AkalRachna K

    2011-11-01

    Full Text Available Abstract Background Allyl isothiocyanate (AITC from mustard is cytotoxic; however the mechanism of its toxicity is unknown. We examined the effects of AITC on heat shock protein (HSP 70 expression in Caenorhabditis elegans. We also examined factors affecting the production of AITC from its precursor, sinigrin, a glucosinolate, in ground Brassica juncea cv. Vulcan seed as mustard has some potential as a biopesticide. Findings An assay to determine the concentration of AITC in ground mustard seed was improved to allow the measurement of AITC release in the first minutes after exposure of ground mustard seed to water. Using this assay, we determined that temperatures above 67°C decreased sinigrin conversion to AITC in hydrated ground B. juncea seed. A pH near 6.0 was found to be necessary for AITC release. RT-qPCR revealed no significant change in HSP70A mRNA expression at low concentrations of AITC ( 1.0 μM resulted in a four- to five-fold increase in expression. A HSP70 ELISA showed that AITC toxicity in C. elegans was ameliorated by the presence of ground seed from low sinigrin B. juncea cv. Arrid. Conclusions • AITC induced toxicity in C. elegans, as measured by HSP70 expression. • Conditions required for the conversion of sinigrin to AITC in ground B. juncea seed were determined. • The use of C. elegans as a bioassay to test AITC or mustard biopesticide efficacy is discussed.

  18. WormBook: the online review of Caenorhabditis elegans biology.

    Science.gov (United States)

    Girard, Lisa R; Fiedler, Tristan J; Harris, Todd W; Carvalho, Felicia; Antoshechkin, Igor; Han, Michael; Sternberg, Paul W; Stein, Lincoln D; Chalfie, Martin

    2007-01-01

    WormBook (www.wormbook.org) is an open-access, online collection of original, peer-reviewed chapters on the biology of Caenorhabditis elegans and related nematodes. Since WormBook was launched in June 2005 with 12 chapters, it has grown to over 100 chapters, covering nearly every aspect of C.elegans research, from Cell Biology and Neurobiology to Evolution and Ecology. WormBook also serves as the text companion to WormBase, the C.elegans model organism database. Objects such as genes, proteins and cells are linked to the relevant pages in WormBase, providing easily accessible background information. Additionally, WormBook chapters contain links to other relevant topics in WormBook, and the in-text citations are linked to their abstracts in PubMed and full-text references, if available. Since WormBook is online, its chapters are able to contain movies and complex images that would not be possible in a print version. WormBook is designed to keep up with the rapid pace of discovery in the field of C.elegans research and continues to grow. WormBook represents a generic publishing infrastructure that is easily adaptable to other research communities to facilitate the dissemination of knowledge in the field.

  19. The lifespan-extending effects of Nymphaea hybrid root extract in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Zhuang, Ziheng; Lv, Ting; Li, Min; Zhang, Yusi; Xue, Ting; Yang, Linsong; Liu, Hui; Zhang, Weiming

    2014-12-01

    Nymphaea hybrid, a water lily from the Nymphaeaceae family, has been found to exhibit some in vivo beneficial effects. In the present study we investigated the lifespan-extending effects of Nymphaea hybrid root extract in the nematode Caenorhabditis elegans. We found that Nymphaea hybrid root extract significantly extended the lifespan of C.elegans and improved its locomotion during aging. Moreover, Nymphaea hybrid root extract increased the resistance of C.elegans to both heat stress and oxidative stress. We found that the ability of Nymphaea hybrid root extract to increase lifespan was independent of its antimicrobial effects and was probably associated with its effects on the reproduction of C.elegans. In addition, the lifespan-extending effects of Nymphaea hybrid root extract were found to be dependent on the insulin/IGF signaling pathway. We also found that total flavones of Nymphaea hybrid could increase survival of C.elegans in both normal and adverse conditions, indicating that total flavones comprise the major fractions with lifespan-extending effects. Therefore, Nymphaea hybrid root extract has lifespan-extending effects in C.elegans and could be developed as a functional food.

  20. Delivery of dietary triglycerides to Caenorhabditis elegans using lipid nanoparticles: Nanoemulsion-based delivery systems.

    Science.gov (United States)

    Colmenares, Daniel; Sun, Quancai; Shen, Peiyi; Yue, Yiren; McClements, D Julian; Park, Yeonhwa

    2016-07-01

    The nematode Caenorhabditis elegans is a powerful tool for studying food bioactives on specific biochemical pathways. However, many food bioactives are highly hydrophobic with extremely low water-solubilities, thereby making them difficult to study using C. elegans. The purpose of this study was to develop nanoemulsion-based systems to deliver hydrophobic molecules in a form that could be ingested by C. elegans. Optical microscopy showed that oil-in-water nanoemulsions with a range of particle diameters (40-500nm) could be ingested by C. elegans. The amount of lipid ingested depended on the size and concentration of the nanoparticles. Fatty acid analysis showed incorporation of conjugated linoleic acid and there was a significant reduction in the fat levels of C. elegans when they were incubated with nanoemulsions containing conjugated linoleic acid, which suggested that this hydrophobic lipid was successfully delivered to the nematodes. The incorporation of hydrophobic molecules into nanoemulsion based-delivery systems may therefore enable their activities to be studied using C. elegans.

  1. Biochemistry and molecular biology of the Caenorhabditis elegans dauer larva

    Energy Technology Data Exchange (ETDEWEB)

    Wadsworth, W.G.

    1989-01-01

    Biochemical and molecular techniques have been used to study the formation and recovery of the developmentally arrested, non-feeding dauer stage of the nematode Caenorhabditis elegans. While investigating developmental transitions in energy metabolism, a major metabolite isolated from perchloric acid extracts has been identified as a modified uridine nucleotide. The compound was isolated by gel filtration and ion-exchange chromatography and its structure was determined by {sup 1}H NMR and {sup 13}C NMR spectroscopy. This compound is the most abundant metabolite detected in {sup 31}PMR spectra of perchloric acid extracts from growing larvae. In the absence of phosphoarginine or phosphocreatine, this modified nucleotide may have an important function in the nematode's energy metabolism, and it may also be found in several other invertebrates. During recovery from the dauer stage, metabolic activation is accompanied by a decrease in intracellular pH (pH{sub i}). Although metabolic activation has been associated with an alkaline pH{sub i} shift in other organisms, in vivo {sup 31}P NMR analysis of recovering dauer larvae shows a pH{sub i} decrease from {approximately}7.3 to {approximately}6.3 within 3 hr after the animals encounter food. This shift occurs before feeding begins, and coincides with, or soon follows, the development commitment to recover from the dauer stage, suggesting that control of pH{sub i} may be important in the regulation of larval development in nematodes. A library enriched for sequences expressed specifically during the L2d (predauer) stage was made by selecting plaques from a genomic lambda library that hybridized to subtracted L2d cDNA probes. Ultimately, three clones that were shown to hybridize only to L2d RNA were selected.

  2. Dynamic changes of histone H3 marks during Caenorhabditis elegans lifecycle revealed by middle-down proteomics

    DEFF Research Database (Denmark)

    Sidoli, Simone; Vandamme, Julien; Elisabetta Salcini, Anna;

    2016-01-01

    We applied a middle-down proteomics strategy for large scale protein analysis during in vivo development of Caenorhabditis elegans. We characterized post-translational modifications (PTMs) on histone H3 N-terminal tails at eight time points during the C. elegans lifecycle, including embryo, larval......-occurring PTMs. We measured temporally distinct combinatorial PTM profiles during C. elegans development. We show that the doubly modified form H3K23me3K27me3, which is rare or non-existent in mammals, is the most abundant PTM in all stages of C. elegans lifecycle. The abundance of H3K23me3 increased during...... that is transmitted during dauer formation. Collectively, our data describe the dynamics of histone H3 combinatorial code during C. elegans lifecycle and demonstrate the feasibility of using middle-down proteomics to study in vivo development of multicellular organisms. This article is protected by copyright. All...

  3. Developmental genetics of secretory vesicle acidification during Caenorhabditis elegans spermatogenesis.

    Science.gov (United States)

    Gleason, Elizabeth J; Hartley, Paul D; Henderson, Melissa; Hill-Harfe, Katherine L; Price, Paul W; Weimer, Robby M; Kroft, Tim L; Zhu, Guang-Dan; Cordovado, Suzanne; L'Hernault, Steven W

    2012-06-01

    Secretory vesicles are used during spermatogenesis to deliver proteins to the cell surface. In Caenorhabditis elegans, secretory membranous organelles (MO) fuse with the plasma membrane to transform spermatids into fertilization-competent spermatozoa. We show that, like the acrosomal vesicle of mammalian sperm, MOs undergo acidification during development. Treatment of spermatids with the V-ATPase inhibitor bafilomycin blocks both MO acidification and formation of functional spermatozoa. There are several spermatogenesis-defective mutants that cause defects in MO morphogenesis, including spe-5. We determined that spe-5, which is on chromosome I, encodes one of two V-ATPase B paralogous subunits. The spe-5 null mutant is viable but sterile because it forms arrested, multi-nucleate spermatocytes. Immunofluorescence with a SPE-5-specific monoclonal antibody shows that SPE-5 expression begins in spermatocytes and is found in all subsequent stages of spermatogenesis. Most SPE-5 is discarded into the residual body during spermatid budding, but a small amount remains in budded spermatids where it localizes to MOs as a discrete dot. The other V-ATPase B subunit is encoded by vha-12, which is located on the X chromosome. Usually, spe-5 mutants are self-sterile in a wild-type vha-12 background. However, an extrachromosomal transgene containing wild-type vha-12 driven by its own promoter allows spe-5 mutant hermaphrodites to produce progeny, indicating that VHA-12 can at least partially substitute for SPE-5. Others have shown that the X chromosome is transcriptionally silent in the male germline, so expression of the autosomally located spe-5 gene ensures that a V-ATPase B subunit is present during spermatogenesis.

  4. Serotonin control of thermotaxis memory behavior in nematode Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Yinxia Li

    Full Text Available Caenorhabditis elegans is as an ideal model system for the study of mechanisms underlying learning and memory. In the present study, we employed C. elegans assay system of thermotaxis memory to investigate the possible role of serotonin neurotransmitter in memory control. Our data showed that both mutations of tph-1, bas-1, and cat-4 genes, required for serotonin synthesis, and mutations of mod-5 gene, encoding a serotonin reuptake transporter, resulted in deficits in thermotaxis memory behavior. Exogenous treatment with serotonin effectively recovered the deficits in thermotaxis memory of tph-1 and bas-1 mutants to the level of wild-type N2. Neuron-specific activity assay of TPH-1 suggests that serotonin might regulate the thermotaxis memory behavior by release from the ADF sensory neurons. Ablation of ADF sensory neurons by expressing a cell-death activator gene egl-1 decreased the thermotaxis memory, whereas activation of ADF neurons by expression of a constitutively active protein kinase C homologue (pkc-1(gf increased the thermotaxis memory and rescued the deficits in thermotaxis memory in tph-1 mutants. Moreover, serotonin released from the ADF sensory neurons might act through the G-protein-coupled serotonin receptors of SER-4 and SER-7 to regulate the thermotaxis memory behavior. Genetic analysis implies that serotonin might further target the insulin signaling pathway to regulate the thermotaxis memory behavior. Thus, our results suggest the possible crucial role of serotonin and ADF sensory neurons in thermotaxis memory control in C. elegans.

  5. Function and regulation of lipid biology in Caenorhabditis elegans aging

    Directory of Open Access Journals (Sweden)

    Nicole Shangming Hou

    2012-05-01

    Full Text Available Rapidly expanding aging populations and a concomitant increase in the prevalence of age-related diseases are global health problems today. Over the past three decades, a large body of work has led to the identification of genes and regulatory networks that affect longevity and health span, often benefitting from the tremendous power of genetics in vertebrate and invertebrate model organisms. Interestingly, many of these factors appear linked to lipids, important molecules that participate in cellular signaling, energy metabolism, and structural compartmentalization. Despite the putative link between lipids and longevity, the role of lipids in aging remains poorly understood. Emerging data from the model organism Caenorhabditis elegans suggest that lipid composition may change during aging, as several pathways that influence aging also regulate lipid metabolism enzymes; moreover, some of these enzymes apparently play key roles in the pathways that affect the rate of aging. By understanding how lipid biology is regulated during C. elegans aging, and how it impacts molecular, cellular and organismal function, we may gain insight into novel ways to delay aging using genetic or pharmacological interventions. In the present review we discuss recent insights into the roles of lipids in C. elegans aging, including regulatory roles played by lipids themselves, the regulation of lipid metabolic enzymes, and the roles of lipid metabolism genes in the pathways that affect aging.

  6. Research progress in neuro-immune interactions in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Jin-ling CAI

    2012-09-01

    Full Text Available The innate immune response may be activated quickly once the organism is invaded by exotic pathogens. An excessive immune response may result in inflammation and tissue damage, whereas an insufficient immune response may result in infection. Nervous system may regulate the intensity of innate immune responses by releasing neurotransmitters, neuropeptides and hormones. Compared with the complicated neuro-immune system in mammals, it is much simpler in Caenorhabditis elegans. Besides, C. elegans is accessible to genetic, molecular biology and behavioral analyses, so it has been used in studies on neuro-immune interactions. It has been revealed recently in the studies with C. elegans that the neuronal pathways regulating innate immune responses primarily include a transforming growth factor-β (TGF-β pathway, an insulin/insulin-like growth factor receptor (IGF pathway and dopaminergic neurotransmission. Since these pathways are evolutionally conservative, so it might be able to provide some new ideas for the research on neuro-immune interactions at molecular levels. The recent progress in this field has been reviewed in present paper.

  7. Goalpha regulates volatile anesthetic action in Caenorhabditis elegans.

    Science.gov (United States)

    van Swinderen, B; Metz, L B; Shebester, L D; Mendel, J E; Sternberg, P W; Crowder, C M

    2001-06-01

    To identify genes controlling volatile anesthetic (VA) action, we have screened through existing Caenorhabditis elegans mutants and found that strains with a reduction in Go signaling are VA resistant. Loss-of-function mutants of the gene goa-1, which codes for the alpha-subunit of Go, have EC(50)s for the VA isoflurane of 1.7- to 2.4-fold that of wild type. Strains overexpressing egl-10, which codes for an RGS protein negatively regulating goa-1, are also isoflurane resistant. However, sensitivity to halothane, a structurally distinct VA, is differentially affected by Go pathway mutants. The RGS overexpressing strains, a goa-1 missense mutant found to carry a novel mutation near the GTP-binding domain, and eat-16(rf) mutants, which suppress goa-1(gf) mutations, are all halothane resistant; goa-1(null) mutants have wild-type sensitivities. Double mutant strains carrying mutations in both goa-1 and unc-64, which codes for a neuronal syntaxin previously found to regulate VA sensitivity, show that the syntaxin mutant phenotypes depend in part on goa-1 expression. Pharmacological assays using the cholinesterase inhibitor aldicarb suggest that VAs and GOA-1 similarly downregulate cholinergic neurotransmitter release in C. elegans. Thus, the mechanism of action of VAs in C. elegans is regulated by Goalpha, and presynaptic Goalpha-effectors are candidate VA molecular targets.

  8. Cell-specific proteomic analysis in Caenorhabditis elegans.

    Science.gov (United States)

    Yuet, Kai P; Doma, Meenakshi K; Ngo, John T; Sweredoski, Michael J; Graham, Robert L J; Moradian, Annie; Hess, Sonja; Schuman, Erin M; Sternberg, Paul W; Tirrell, David A

    2015-03-03

    Proteomic analysis of rare cells in heterogeneous environments presents difficult challenges. Systematic methods are needed to enrich, identify, and quantify proteins expressed in specific cells in complex biological systems including multicellular plants and animals. Here, we have engineered a Caenorhabditis elegans phenylalanyl-tRNA synthetase capable of tagging proteins with the reactive noncanonical amino acid p-azido-L-phenylalanine. We achieved spatiotemporal selectivity in the labeling of C. elegans proteins by controlling expression of the mutant synthetase using cell-selective (body wall muscles, intestinal epithelial cells, neurons, and pharyngeal muscle) or state-selective (heat-shock) promoters in several transgenic lines. Tagged proteins are distinguished from the rest of the protein pool through bioorthogonal conjugation of the azide side chain to probes that permit visualization and isolation of labeled proteins. By coupling our methodology with stable-isotope labeling of amino acids in cell culture (SILAC), we successfully profiled proteins expressed in pharyngeal muscle cells, and in the process, identified proteins not previously known to be expressed in these cells. Our results show that tagging proteins with spatiotemporal selectivity can be achieved in C. elegans and illustrate a convenient and effective approach for unbiased discovery of proteins expressed in targeted subsets of cells.

  9. Caenorhabditis elegans is a useful model for anthelmintic discovery

    Science.gov (United States)

    Burns, Andrew R.; Luciani, Genna M.; Musso, Gabriel; Bagg, Rachel; Yeo, May; Zhang, Yuqian; Rajendran, Luckshika; Glavin, John; Hunter, Robert; Redman, Elizabeth; Stasiuk, Susan; Schertzberg, Michael; Angus McQuibban, G.; Caffrey, Conor R.; Cutler, Sean R.; Tyers, Mike; Giaever, Guri; Nislow, Corey; Fraser, Andy G.; MacRae, Calum A.; Gilleard, John; Roy, Peter J.

    2015-01-01

    Parasitic nematodes infect one quarter of the world's population and impact all humans through widespread infection of crops and livestock. Resistance to current anthelmintics has prompted the search for new drugs. Traditional screens that rely on parasitic worms are costly and labour intensive and target-based approaches have failed to yield novel anthelmintics. Here, we present our screen of 67,012 compounds to identify those that kill the non-parasitic nematode Caenorhabditis elegans. We then rescreen our hits in two parasitic nematode species and two vertebrate models (HEK293 cells and zebrafish), and identify 30 structurally distinct anthelmintic lead molecules. Genetic screens of 19 million C. elegans mutants reveal those nematicides for which the generation of resistance is and is not likely. We identify the target of one lead with nematode specificity and nanomolar potency as complex II of the electron transport chain. This work establishes C. elegans as an effective and cost-efficient model system for anthelmintic discovery. PMID:26108372

  10. Biomechanical analysis of gait adaptation in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Fang-Yen, Christopher; Wyart, Matthieu; Xie, Julie; Kawai, Risa; Kodger, Tom; Chen, Sway; Wen, Quan; Samuel, Aravinthan D T

    2010-11-23

    To navigate different environments, an animal must be able to adapt its locomotory gait to its physical surroundings. The nematode Caenorhabditis elegans, between swimming in water and crawling on surfaces, adapts its locomotory gait to surroundings that impose approximately 10,000-fold differences in mechanical resistance. Here we investigate this feat by studying the undulatory movements of C. elegans in Newtonian fluids spanning nearly five orders of magnitude in viscosity. In these fluids, the worm undulatory gait varies continuously with changes in external load: As load increases, both wavelength and frequency of undulation decrease. We also quantify the internal viscoelastic properties of the worm's body and their role in locomotory dynamics. We incorporate muscle activity, internal load, and external load into a biomechanical model of locomotion and show that (i) muscle power is nearly constant across changes in locomotory gait, and (ii) the onset of gait adaptation occurs as external load becomes comparable to internal load. During the swimming gait, which is evoked by small external loads, muscle power is primarily devoted to bending the worm's elastic body. During the crawling gait, evoked by large external loads, comparable muscle power is used to drive the external load and the elastic body. Our results suggest that C. elegans locomotory gait continuously adapts to external mechanical load in order to maintain propulsive thrust.

  11. Function and Regulation of Lipid Biology in Caenorhabditis elegans Aging

    Science.gov (United States)

    Hou, Nicole Shangming; Taubert, Stefan

    2012-01-01

    Rapidly expanding aging populations and a concomitant increase in the prevalence of age-related diseases are global health problems today. Over the past three decades, a large body of work has led to the identification of genes and regulatory networks that affect longevity and health span, often benefiting from the tremendous power of genetics in vertebrate and invertebrate model organisms. Interestingly, many of these factors appear linked to lipids, important molecules that participate in cellular signaling, energy metabolism, and structural compartmentalization. Despite the putative link between lipids and longevity, the role of lipids in aging remains poorly understood. Emerging data from the model organism Caenorhabditis elegans suggest that lipid composition may change during aging, as several pathways that influence aging also regulate lipid metabolism enzymes; moreover, some of these enzymes apparently play key roles in the pathways that affect the rate of aging. By understanding how lipid biology is regulated during C. elegans aging, and how it impacts molecular, cellular, and organismal function, we may gain insight into novel ways to delay aging using genetic or pharmacological interventions. In the present review we discuss recent insights into the roles of lipids in C. elegans aging, including regulatory roles played by lipids themselves, the regulation of lipid metabolic enzymes, and the roles of lipid metabolism genes in the pathways that affect aging. PMID:22629250

  12. Black tea increased survival of Caenorhabditis elegans under stress.

    Science.gov (United States)

    Xiong, Li-Gui; Huang, Jian-An; Li, Juan; Yu, Peng-Hui; Xiong, Zhe; Zhang, Jian-Wei; Gong, Yu-Shun; Liu, Zhong-Hua; Chen, Jin-Hua

    2014-11-19

    The present study examined the effects of black tea (Camellia sinensis) extracts (BTE) in Caenorhabditis elegans under various abiotic stressors. Results showed BTE increased nematode resistance to osmosis, heat, and UV irradiation treatments. However, BTE could not increase nematodes' lifespan under normal culture conditions and MnCl2-induced toxicity at concentrations we used. Further studies showed that BTE decreased reactive oxygen species and up-regulated some antioxidant enzymes, including GSH-PX, and genes, such as gsh-px and sod-3. However, only a slight extension in mev-1 mutants mean lifespan was observed without significance. These results indicated that the antioxidant activity of BTE might be necessary but not sufficient to protect against aging to C. elegans. Moreover, BTE increased the mRNA level of stress-response genes such as sir-2.1 and sek-1. Our finding demonstrated BTE might increase heat and UV stress resistance in a sir.2.1-dependent manner. Taken together, BTE enhanced stress resistance with multiple mechanisms in C. elegans.

  13. On-demand optical immobilization of Caenorhabditis elegans for high-resolution imaging and microinjection.

    Science.gov (United States)

    Hwang, Hyundoo; Krajniak, Jan; Matsunaga, Yohei; Benian, Guy M; Lu, Hang

    2014-09-21

    This paper describes a novel selective immobilization technique based on optical control of the sol-gel transition of thermoreversible Pluronic gel, which provides a simple, versatile, and biocompatible approach for high-resolution imaging and microinjection of Caenorhabditis elegans.

  14. DNA Strand Breaks in Mitotic Germ Cells of Caenorhabditis elegans Evaluated by Comet Assay.

    Science.gov (United States)

    Park, Sojin; Choi, Seoyun; Ahn, Byungchan

    2016-03-01

    DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents.

  15. A heritable antiviral RNAi response limits Orsay virus infection in Caenorhabditis elegans N2.

    Directory of Open Access Journals (Sweden)

    Mark G Sterken

    Full Text Available Orsay virus (OrV is the first virus known to be able to complete a full infection cycle in the model nematode species Caenorhabditis elegans. OrV is transmitted horizontally and its infection is limited by antiviral RNA interference (RNAi. However, we have no insight into the kinetics of OrV replication in C. elegans. We developed an assay that infects worms in liquid, allowing precise monitoring of the infection. The assay revealed a dual role for the RNAi response in limiting Orsay virus infection in C. elegans. Firstly, it limits the progression of the initial infection at the step of recognition of dsRNA. Secondly, it provides an inherited protection against infection in the offspring. This establishes the heritable RNAi response as anti-viral mechanism during OrV infections in C. elegans. Our results further illustrate that the inheritance of the anti-viral response is important in controlling the infection in the canonical wild type Bristol N2. The OrV replication kinetics were established throughout the worm life-cycle, setting a standard for further quantitative assays with the OrV-C. elegans infection model.

  16. Improving the Caenorhabditis elegans genome annotation using machine learning.

    Directory of Open Access Journals (Sweden)

    Gunnar Rätsch

    2007-02-01

    Full Text Available For modern biology, precise genome annotations are of prime importance, as they allow the accurate definition of genic regions. We employ state-of-the-art machine learning methods to assay and improve the accuracy of the genome annotation of the nematode Caenorhabditis elegans. The proposed machine learning system is trained to recognize exons and introns on the unspliced mRNA, utilizing recent advances in support vector machines and label sequence learning. In 87% (coding and untranslated regions and 95% (coding regions only of all genes tested in several out-of-sample evaluations, our method correctly identified all exons and introns. Notably, only 37% and 50%, respectively, of the presently unconfirmed genes in the C. elegans genome annotation agree with our predictions, thus we hypothesize that a sizable fraction of those genes are not correctly annotated. A retrospective evaluation of the Wormbase WS120 annotation [] of C. elegans reveals that splice form predictions on unconfirmed genes in WS120 are inaccurate in about 18% of the considered cases, while our predictions deviate from the truth only in 10%-13%. We experimentally analyzed 20 controversial genes on which our system and the annotation disagree, confirming the superiority of our predictions. While our method correctly predicted 75% of those cases, the standard annotation was never completely correct. The accuracy of our system is further corroborated by a comparison with two other recently proposed systems that can be used for splice form prediction: SNAP and ExonHunter. We conclude that the genome annotation of C. elegans and other organisms can be greatly enhanced using modern machine learning technology.

  17. A soil bioassay using the nematode Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.N.; Peredney, C.L.; Williams, P.L.

    1999-07-01

    Caenorhabditis elegans is a free-livings soil nematode that is commonly used as a biological model. Recently, much work has been done using the nematode as a toxicological model as well. Much of the work involving C. elegans has been performed in aquatic media, since it lives in the interstitial water of soil. However, testing in soil would be expected to more accurately reproduce the organism's normal environment and may take into consideration other factors not available in an aquatic test, i.e., toxicant availability effects due to sorption, various chemical interactions, etc. This study used a modification of a previous experimental protocol to determine 24h LC{sub 50} values for Cu in a Cecil series soil mixture, and examined the use of CuCl{sub 2} as a reference toxicant for soil toxicity testing with C. elegans. Three different methods of determining percent lethality were used, each dependent on how the number of worms missing after the recovery process was used in the lethality calculations. Only tests having {ge}80% worm recovery and {ge}90% control survival were used in determining the LC{sub 50}s, by Probit analysis. The replicate LC{sub 50} values generated a control chart for each method of calculating percent lethality. The coefficient of variation (CV) for each of the three methods was {le}14%. The control charts and the protocol outlined in this study are intended to be used to assess test organism health and monitor precision of future soil toxicity tests with C. elegans.

  18. Chaperone-interacting TPR proteins in Caenorhabditis elegans.

    Science.gov (United States)

    Haslbeck, Veronika; Eckl, Julia M; Kaiser, Christoph J O; Papsdorf, Katharina; Hessling, Martin; Richter, Klaus

    2013-08-23

    The ATP-hydrolyzing molecular chaperones Hsc70/Hsp70 and Hsp90 bind a diverse set of tetratricopeptide repeat (TPR)-containing cofactors via their C-terminal peptide motifs IEEVD and MEEVD. These cochaperones contribute to substrate turnover and confer specific activities to the chaperones. Higher eukaryotic genomes encode a large number of TPR-domain-containing proteins. The human proteome contains more than 200 TPR proteins, and that of Caenorhabditis elegans, about 80. It is unknown how many of them interact with Hsc70 or Hsp90. We systematically screened the C. elegans proteome for TPR-domain-containing proteins that likely interact with Hsc70 and Hsp90 and ranked them due to their similarity with known chaperone-interacting TPRs. We find C. elegans to encode many TPR proteins, which are not present in yeast. All of these have homologs in fruit fly or humans. Highly ranking uncharacterized open reading frames C33H5.8, C34B2.5 and ZK370.8 may encode weakly conserved homologs of the human proteins RPAP3, TTC1 and TOM70. C34B2.5 and ZK370.8 bind both Hsc70 and Hsp90 with low micromolar affinities. Mutation of amino acids involved in EEVD binding disrupts the interaction. In vivo, ZK370.8 is localized to mitochondria in tissues with known chaperone requirements, while C34B2.5 colocalizes with Hsc70 in intestinal cells. The highest-ranking open reading frame with non-conserved EEVD-interacting residues, F52H3.5, did not show any binding to Hsc70 or Hsp90, suggesting that only about 15 of the TPR-domain-containing proteins in C. elegans interact with chaperones, while the many others may have evolved to bind other ligands.

  19. Genomic analysis of stress response against arsenic in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Surasri N Sahu

    Full Text Available Arsenic, a known human carcinogen, is widely distributed around the world and found in particularly high concentrations in certain regions including Southwestern US, Eastern Europe, India, China, Taiwan and Mexico. Chronic arsenic poisoning affects millions of people worldwide and is associated with increased risk of many diseases including arthrosclerosis, diabetes and cancer. In this study, we explored genome level global responses to high and low levels of arsenic exposure in Caenorhabditis elegans using Affymetrix expression microarrays. This experimental design allows us to do microarray analysis of dose-response relationships of global gene expression patterns. High dose (0.03% exposure caused stronger global gene expression changes in comparison with low dose (0.003% exposure, suggesting a positive dose-response correlation. Biological processes such as oxidative stress, and iron metabolism, which were previously reported to be involved in arsenic toxicity studies using cultured cells, experimental animals, and humans, were found to be affected in C. elegans. We performed genome-wide gene expression comparisons between our microarray data and publicly available C. elegans microarray datasets of cadmium, and sediment exposure samples of German rivers Rhine and Elbe. Bioinformatics analysis of arsenic-responsive regulatory networks were done using FastMEDUSA program. FastMEDUSA analysis identified cancer-related genes, particularly genes associated with leukemia, such as dnj-11, which encodes a protein orthologous to the mammalian ZRF1/MIDA1/MPP11/DNAJC2 family of ribosome-associated molecular chaperones. We analyzed the protective functions of several of the identified genes using RNAi. Our study indicates that C. elegans could be a substitute model to study the mechanism of metal toxicity using high-throughput expression data and bioinformatics tools such as FastMEDUSA.

  20. The diverse functions of germline P-granules in Caenorhabditis elegans.

    Science.gov (United States)

    Voronina, Ekaterina

    2013-08-01

    P-granules are conserved cytoplasmic organelles, similar to nuage, that are present in Caenorhabditis elegans germ cells. Based on the prevailing sterility phenotype of the component mutants, P-granules have been seen as regulators of germ cell development and function. Yet, specific germline defects resulting from P-granule failure vary, depending on which component(s) are inactivated, at which stage of development, as well as on the presence of stress factors during animal culture. This review discusses the unifying themes in many P-granule functions, with the main focus on their role as organizing centers nucleating RNA regulation in the germ cell cytoplasm.

  1. Kinetics and specificity of paternal mitochondrial elimination in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Yang; Zhang, Yi; Chen, Lianwan; Liang, Qian; Yin, Xiao-Ming; Miao, Long; Kang, Byung-Ho; Xue, Ding

    2016-09-01

    In most eukaryotes, mitochondria are inherited maternally. The autophagy process is critical for paternal mitochondrial elimination (PME) in Caenorhabditis elegans, but how paternal mitochondria, but not maternal mitochondria, are selectively targeted for degradation is poorly understood. Here we report that mitochondrial dynamics have a profound effect on PME. A defect in fission of paternal mitochondria delays PME, whereas a defect in fusion of paternal mitochondria accelerates PME. Surprisingly, a defect in maternal mitochondrial fusion delays PME, which is reversed by a fission defect in maternal mitochondria or by increasing maternal mitochondrial membrane potential using oligomycin. Electron microscopy and tomography analyses reveal that a proportion of maternal mitochondria are compromised when they fail to fuse normally, leading to their competition for the autophagy machinery with damaged paternal mitochondria and delayed PME. Our study indicates that mitochondrial dynamics play a critical role in regulating both the kinetics and the specificity of PME.

  2. Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior

    Science.gov (United States)

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2013-03-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its simple nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair was sufficient to force the animal to locate, turn towards and track virtual light gradients.

  3. Kinetics and specificity of paternal mitochondrial elimination in Caenorhabditis elegans

    Science.gov (United States)

    Wang, Yang; Zhang, Yi; Chen, Lianwan; Liang, Qian; Yin, Xiao-Ming; Miao, Long; Kang, Byung-Ho; Xue, Ding

    2016-01-01

    In most eukaryotes, mitochondria are inherited maternally. The autophagy process is critical for paternal mitochondrial elimination (PME) in Caenorhabditis elegans, but how paternal mitochondria, but not maternal mitochondria, are selectively targeted for degradation is poorly understood. Here we report that mitochondrial dynamics have a profound effect on PME. A defect in fission of paternal mitochondria delays PME, whereas a defect in fusion of paternal mitochondria accelerates PME. Surprisingly, a defect in maternal mitochondrial fusion delays PME, which is reversed by a fission defect in maternal mitochondria or by increasing maternal mitochondrial membrane potential using oligomycin. Electron microscopy and tomography analyses reveal that a proportion of maternal mitochondria are compromised when they fail to fuse normally, leading to their competition for the autophagy machinery with damaged paternal mitochondria and delayed PME. Our study indicates that mitochondrial dynamics play a critical role in regulating both the kinetics and the specificity of PME. PMID:27581092

  4. Radiosensitivity Parameters For Lethal Mutagenesis In Caenorhabditis Elegans

    Energy Technology Data Exchange (ETDEWEB)

    Cucinotta, F.A.; Wilson, J.W.; Katz, R.

    1994-01-01

    For the first time track structure theory has been applied to radiobiological effects in a living organism. Data for lethal mutagenesis in Caenorhabditis elegans, obtained after irradiation with nine different types of ions of atomic number 1-57 and gamma rays have yielded radiosensitivity parameters (E{sub 0}, sigma{sub 0}, Kappa, m = 68 Gy, 2.5 x 10(exp {minus}9) cm (exp 2), 750, 2) comparable with those found for the transformation of C3HT10 1/2 cells (180 Gy, 1.15 x 10(exp {minus}10) cm(exp 2), 750, 2) but remote from those (E{sub 0} and sigma{sub 0} = approx. 2 Gy, approx. 5 x 10(exp {minus}7) cm(exp 2)) for mammalian cell survival.

  5. The epidermal growth factor system in Caenorhabditis elegans.

    Science.gov (United States)

    Moghal, Nadeem; Sternberg, Paul W

    2003-03-10

    The single known epidermal growth factor-like growth factor and single epidermal growth factor receptor in Caenorhabditis elegans mediate two types of processes, each via a distinct signal transduction pathway. Several instances of cell fate specification during organogenesis require the RAS-MAP kinase pathway, as well as multiple nuclear factors. By contrast, appropriate myoepithelial contractions during ovulation involve IP3-mediated signal transduction. Positive modulators of the RAS pathway include KSR, SUR-8, phosphatase PP2A, and a zinc cation diffusion facilitator. Negative regulators of the RAS pathway include homologs of CBL, GAP-1, ACK, and MAP kinase phosphatase, while negative regulators of the IP3 pathway are enzymes that modify IP3. In addition to its stimulation of RAS activity, the GRB2 homolog SEM-5 acts negatively on both signaling pathways, as does the Ack-related kinase ARK-1.

  6. Student Learning of Early Embryonic Development via the Utilization of Research Resources from the Nematode "Caenorhabditis elegans"

    Science.gov (United States)

    Lu, Fong-Mei; Eliceiri, Kevin W.; Squirrell, Jayne M.; White, John G.; Stewart, James

    2008-01-01

    This study was undertaken to gain insights into undergraduate students' understanding of early embryonic development, specifically, how well they comprehend the concepts of volume constancy, cell lineages, body plan axes, and temporal and spatial dimensionality in development. To study student learning, a curriculum was developed incorporating…

  7. The Si elegans project at the interface of experimental and computational Caenorhabditis elegans neurobiology and behavior

    Science.gov (United States)

    Petrushin, Alexey; Ferrara, Lorenzo; Blau, Axel

    2016-12-01

    Objective. In light of recent progress in mapping neural function to behavior, we briefly and selectively review past and present endeavors to reveal and reconstruct nervous system function in Caenorhabditis elegans through simulation. Approach. Rather than presenting an all-encompassing review on the mathematical modeling of C. elegans, this contribution collects snapshots of pathfinding key works and emerging technologies that recent single- and multi-center simulation initiatives are building on. We thereby point out a few general limitations and problems that these undertakings are faced with and discuss how these may be addressed and overcome. Main results. Lessons learned from past and current computational approaches to deciphering and reconstructing information flow in the C. elegans nervous system corroborate the need of refining neural response models and linking them to intra- and extra-environmental interactions to better reflect and understand the actual biological, biochemical and biophysical events that lead to behavior. Together with single-center research efforts, the Si elegans and OpenWorm projects aim at providing the required, in some cases complementary tools for different hardware architectures to support advancement into this direction. Significance. Despite its seeming simplicity, the nervous system of the hermaphroditic nematode C. elegans with just 302 neurons gives rise to a rich behavioral repertoire. Besides controlling vital functions (feeding, defecation, reproduction), it encodes different stimuli-induced as well as autonomous locomotion modalities (crawling, swimming and jumping). For this dichotomy between system simplicity and behavioral complexity, C. elegans has challenged neurobiologists and computational scientists alike. Understanding the underlying mechanisms that lead to a context-modulated functionality of individual neurons would not only advance our knowledge on nervous system function and its failure in pathological

  8. Mapping a Mutation in "Caenorhabditis elegans" Using a Polymerase Chain Reaction-Based Approach

    Science.gov (United States)

    Myers, Edith M.

    2014-01-01

    Many single nucleotide polymorphisms (SNPs) have been identified within the "Caenorhabditis elegans" genome. SNPs present in the genomes of two isogenic "C. elegans" strains have been routinely used as a tool in forward genetics to map a mutation to a particular chromosome. This article describes a laboratory exercise in which…

  9. Multiple sensory G proteins in the olfactory, gustatory and nociceptive neurons modulate longevity in Caenorhabditis elegans

    NARCIS (Netherlands)

    H. Lans (Hannes); G. Jansen (Gert)

    2007-01-01

    textabstractThe life span of the nematode Caenorhabditis elegans is under control of sensory signals detected by the amphid neurons. In these neurons, C. elegans expresses at least 13 Galpha subunits and a Ggamma subunit, which are involved in the transduction and modulation of sensory signals. Here

  10. A potential biochemical mechanism underlying the influence of sterol deprivation stress on Caenorhabditis elegans longevity

    Science.gov (United States)

    To investigate the biochemical mechanism for sterol-mediated alteration in aging in Caenorhabditis elegans, we established sterol depletion conditions by treating worms with azacoprostane, which reduced mean lifespan of adult C. elegans by 35%. Proteomic analyses of egg proteins from treated and un...

  11. WormBase: network access to the genome and biology of Caenorhabditis elegans.

    Science.gov (United States)

    Stein, L; Sternberg, P; Durbin, R; Thierry-Mieg, J; Spieth, J

    2001-01-01

    WormBase (http://www.wormbase.org) is a web-based resource for the Caenorhabditis elegans genome and its biology. It builds upon the existing ACeDB database of the C.elegans genome by providing data curation services, a significantly expanded range of subject areas and a user-friendly front end.

  12. A High-Throughput Method for the Analysis of Larval Developmental Phenotypes in Caenorhabditis elegans.

    Science.gov (United States)

    Olmedo, María; Geibel, Mirjam; Artal-Sanz, Marta; Merrow, Martha

    2015-10-01

    Caenorhabditis elegans postembryonic development consists of four discrete larval stages separated by molts. Typically, the speed of progression through these larval stages is investigated by visual inspection of the molting process. Here, we describe an automated method to monitor the timing of these discrete phases of C. elegans maturation, from the first larval stage through adulthood, using bioluminescence. The method was validated with a lin-42 mutant strain that shows delayed development relative to wild-type animals and with a daf-2 mutant that shows an extended second larval stage. This new method is inherently high-throughput and will finally allow dissecting the molecular machinery governing the speed of the developmental clock, which has so far been hampered by the lack of a method suitable for genetic screens.

  13. Curcumin-mediated lifespan extension in Caenorhabditis elegans.

    Science.gov (United States)

    Liao, Vivian Hsiu-Chuan; Yu, Chan-Wei; Chu, Yu-Ju; Li, Wen-Hsuan; Hsieh, Yi-Chen; Wang, Teng-Ting

    2011-10-01

    Curcumin is the active ingredient in the herbal medicine and dietary spice, turmeric (Curcuma longa). It has a wide range of biological activities, including anti-inflammatory, antioxidant, chemopreventive, and chemotherapeutic activities. We examined the effects of curcumin on the lifespan and aging in Caenorhabditis elegans, and found that it responded to curcumin with an increased lifespan and reduced intracellular reactive oxygen species and lipofuscin during aging. We analyzed factors that might influence lifespan extension by curcumin. We showed that lifespan extension by curcumin in C. elegans is attributed to its antioxidative properties but not its antimicrobial properties. Moreover, we showed that lifespan extension had effects on body size and the pharyngeal pumping rate but not on reproduction. Finally, lifespan tests with selected stress- and lifespan-relevant mutant strains revealed that the lifespan-extending phenotype was absent from the osr-1, sek-1, mek-1, skn-1, unc-43, sir-2.1, and age-1 mutants, whereas curcumin treatment prolonged the lifespan of mev-1 and daf-16 mutants. Our study has unraveled a diversity of modes of action and signaling pathways to longevity and aging with curcumin exposure in vivo.

  14. Computer-Assisted Transgenesis of Caenorhabditis elegans for Deep Phenotyping.

    Science.gov (United States)

    Gilleland, Cody L; Falls, Adam T; Noraky, James; Heiman, Maxwell G; Yanik, Mehmet F

    2015-09-01

    A major goal in the study of human diseases is to assign functions to genes or genetic variants. The model organism Caenorhabditis elegans provides a powerful tool because homologs of many human genes are identifiable, and large collections of genetic vectors and mutant strains are available. However, the delivery of such vector libraries into mutant strains remains a long-standing experimental bottleneck for phenotypic analysis. Here, we present a computer-assisted microinjection platform to streamline the production of transgenic C. elegans with multiple vectors for deep phenotyping. Briefly, animals are immobilized in a temperature-sensitive hydrogel using a standard multiwell platform. Microinjections are then performed under control of an automated microscope using precision robotics driven by customized computer vision algorithms. We demonstrate utility by phenotyping the morphology of 12 neuronal classes in six mutant backgrounds using combinations of neuron-type-specific fluorescent reporters. This technology can industrialize the assignment of in vivo gene function by enabling large-scale transgenic engineering.

  15. Differential Toxicities of Nickel Salts to the Nematode Caenorhabditis elegans.

    Science.gov (United States)

    Meyer, Dean; Birdsey, Jennifer M; Wendolowski, Mark A; Dobbin, Kevin K; Williams, Phillip L

    2016-08-01

    This study focused on assessing whether nickel (Ni) toxicity to the nematode Caenorhabditis elegans was affected by the molecular structure of the Ni salt used. Nematodes were exposed to seven Ni salts [Ni sulfate hexahydrate (NiSO4·6H2O), Ni chloride hexahydrate (NiCl2·6H2O), Ni acetate tetrahydrate (Ni(OCOCH3)2·4H2O), Ni nitrate hexahydrate (N2NiO6·6H2O), anhydrous Ni iodide (NiI2), Ni sulfamate hydrate (Ni(SO3NH2)2·H2O), and Ni fluoride tetrahydrate (NiF2·4H2O)] in an aquatic medium for 24 h, and lethality curves were generated and analyzed. Ni fluoride, Ni iodide, and Ni chloride were most toxic to C. elegans, followed by Ni nitrate, Ni sulfamate, Ni acetate, and Ni sulfate. The LC50 values of the halogen-containing salts were statistically different from the corresponding value of the least toxic salt, Ni sulfate. This finding is consistent with the expected high bioavailability of free Ni ions in halide solutions. We recommend that the halide salts be used in future Ni testing involving aquatic invertebrates.

  16. Mitoflash frequency in early adulthood predicts lifespan in Caenorhabditis elegans

    Science.gov (United States)

    Shen, En-Zhi; Song, Chun-Qing; Lin, Yuan; Zhang, Wen-Hong; Su, Pei-Fang; Liu, Wen-Yuan; Zhang, Pan; Xu, Jiejia; Lin, Na; Zhan, Cheng; Wang, Xianhua; Shyr, Yu; Cheng, Heping; Dong, Meng-Qiu

    2014-04-01

    It has been theorized for decades that mitochondria act as the biological clock of ageing, but the evidence is incomplete. Here we show a strong coupling between mitochondrial function and ageing by in vivo visualization of the mitochondrial flash (mitoflash), a frequency-coded optical readout reflecting free-radical production and energy metabolism at the single-mitochondrion level. Mitoflash activity in Caenorhabditis elegans pharyngeal muscles peaked on adult day 3 during active reproduction and on day 9 when animals started to die off. A plethora of genetic mutations and environmental factors inversely modified the lifespan and the day-3 mitoflash frequency. Even within an isogenic population, the day-3 mitoflash frequency was negatively correlated with the lifespan of individual animals. Furthermore, enhanced activity of the glyoxylate cycle contributed to the decreased day-3 mitoflash frequency and the longevity of daf-2 mutant animals. These results demonstrate that the day-3 mitoflash frequency is a powerful predictor of C. elegans lifespan across genetic, environmental and stochastic factors. They also support the notion that the rate of ageing, although adjustable in later life, has been set to a considerable degree before reproduction ceases.

  17. Magnetosensitive neurons mediate geomagnetic orientation in Caenorhabditis elegans

    Science.gov (United States)

    Vidal-Gadea, Andrés; Ward, Kristi; Beron, Celia; Ghorashian, Navid; Gokce, Sertan; Russell, Joshua; Truong, Nicholas; Parikh, Adhishri; Gadea, Otilia; Ben-Yakar, Adela; Pierce-Shimomura, Jonathan

    2015-01-01

    Many organisms spanning from bacteria to mammals orient to the earth's magnetic field. For a few animals, central neurons responsive to earth-strength magnetic fields have been identified; however, magnetosensory neurons have yet to be identified in any animal. We show that the nematode Caenorhabditis elegans orients to the earth's magnetic field during vertical burrowing migrations. Well-fed worms migrated up, while starved worms migrated down. Populations isolated from around the world, migrated at angles to the magnetic vector that would optimize vertical translation in their native soil, with northern- and southern-hemisphere worms displaying opposite migratory preferences. Magnetic orientation and vertical migrations required the TAX-4 cyclic nucleotide-gated ion channel in the AFD sensory neuron pair. Calcium imaging showed that these neurons respond to magnetic fields even without synaptic input. C. elegans may have adapted magnetic orientation to simplify their vertical burrowing migration by reducing the orientation task from three dimensions to one. DOI: http://dx.doi.org/10.7554/eLife.07493.001 PMID:26083711

  18. Hierarchical sparse coding in the sensory system of Caenorhabditis elegans.

    Science.gov (United States)

    Zaslaver, Alon; Liani, Idan; Shtangel, Oshrat; Ginzburg, Shira; Yee, Lisa; Sternberg, Paul W

    2015-01-27

    Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons. This library includes the vast majority of the sensory system in C. elegans. Imaging from individual sensory neurons while subjecting the worms to various stimuli allowed us to compile a comprehensive functional map of the sensory system at single neuron resolution. The functional map reveals that despite the dense wiring, chemosensory neurons represent the environment using sparse codes. Moreover, although anatomically closely connected, chemo- and mechano-sensory neurons are functionally segregated. In addition, the code is hierarchical, where few neurons participate in encoding multiple cues, whereas other sensory neurons are stimulus specific. This encoding strategy may have evolved to mitigate the constraints of a compact sensory system.

  19. Enhanced growth and reproduction of Caenorhabditis elegans (Nematoda) in the presence of 4-Nonylphenol

    Energy Technology Data Exchange (ETDEWEB)

    Hoess, Sebastian; Juettner, I.Ingrid; Traunspurger, Walter; Pfister, Gerd; Schramm, K.-W.; Steinberg, C.E.W

    2002-12-01

    4-Nonylphenol can enhance growth and reproduction of the nematode Caenorhabditis elegans. - The nematode Caenorhabditis elegans was exposed over a whole life-cycle (72 h) to several concentrations of 4-nonylphenol (NP; nominal concentrations: 0-350 {mu}g/l). Growth and reproduction of C. elegans were enhanced at NP concentrations of 66 and 40 {mu}g/l, respectively, with effects showing dose-response relationships. These stimulatory effects might be of ecological relevance in benthic habitats, where organisms can be exposed to high concentrations of NP.

  20. Anti-aging properties of Ribes fasciculatum in Caenorhabditis elegans.

    Science.gov (United States)

    Jeon, Hoon; Cha, Dong Seok

    2016-05-01

    The present study investigated the effects and underlying mechanism of ethylacetate fraction of Ribes fasciculatum (ERF) on the lifespan and stress tolerance using a Caenorhabditis elegans model. The longevity activity of ERF was determined by lifespan assay under normal culture condition. The survival rate of nematodes under various stress conditions was assessed to validate the effects of ERF on the stress tolerance. To determine the antioxidant potential of ERF, the superoxide dismutase (SOD) activities and intracellular reactive oxygen species (ROS) levels were investigated. The ERF-mediated change in SOD-3 expression was examined using GFP-expressing transgenic strain. The effects of ERF on the aging-related factors were investigated by reproduction assay and pharyngeal pumping assay. The intestinal lipofuscin levels of aged nematodes were also measured. The mechanistic studies were performed using selected mutant strains. Our results indicated that ERF showed potent lifespan extension effects on the wild-type nematode under both normal and various stress conditions. The ERF treatment also enhanced the activity and expression of superoxide dismutase (SOD) and attenuated the intracellular ROS levels. Moreover, ERF-fed nematodes showed decreased lipofuscin accumulation, indicating ERF might affect age-associated changes in C. elegans. The results of mechanistic studies indicated that there was no significant lifespan extension in ERF-treated daf-2, age-1, sir-2.1, and daf-16 null mutants, suggesting that they were involved in ERF-mediated lifespan regulation. In conclusion, R. fasciculatum confers increased longevity and stress resistance in C. elegans via SIR-2.1-mediated DAF-16 activation, dependent on the insulin/IGF signaling pathway.

  1. Mechanism underlying prolongevity induced by bifidobacteria in Caenorhabditis elegans.

    Science.gov (United States)

    Komura, Tomomi; Ikeda, Takanori; Yasui, Chikako; Saeki, Shigeru; Nishikawa, Yoshikazu

    2013-02-01

    Lactobacilli and bifidobacteria are probiotic bacteria that modify host defense systems and have the ability to extend the lifespan of the nematode Caenorhabditis elegans. Here, we attempted to elucidate the mechanism by which bifidobacteria prolong the lifespan of C. elegans. When the nematode was fed Bifidobacterium infantis (BI) mixed at various ratios with the standard food bacterium Escherichia coli strain OP50 (OP), the mean lifespan of worms was extended in a dose-dependent manner. Worms fed BI displayed higher locomotion and produced more offspring than control worms. The growth curves of nematodes were similar regardless of the amount of BI mixed with OP, suggesting that BI did not induce prolongevity effects through caloric restriction. Notably, feeding worms the cell wall fraction of BI alone was sufficient to promote prolongevity. The accumulation of protein carbonyls and lipofuscin, a biochemical marker of aging, was also lower in worms fed BI; however, the worms displayed similar susceptibility to heat, hydrogen peroxide, and paraquat, an inducer of free radicals, as the control worms. As a result of BI feeding, loss-of-function mutants of daf-16, jnk-1, aak-2, tol-1, and tir-1 exhibited a longer lifespan than OP-fed control worms, but BI failed to extend the lifespan of pmk-1, skn-1, and vhp-1 mutants. As skn-1 induces phase 2 detoxification enzymes, our findings suggest that cell wall components of bifidobacteria increase the average lifespan of C. elegans via activation of skn-1, regulated by the p38 MAPK pathway, but not by general activation of the host defense system via DAF-16.

  2. Structural properties of the Caenorhabditis elegans neuronal network.

    Science.gov (United States)

    Varshney, Lav R; Chen, Beth L; Paniagua, Eric; Hall, David H; Chklovskii, Dmitri B

    2011-02-03

    Despite recent interest in reconstructing neuronal networks, complete wiring diagrams on the level of individual synapses remain scarce and the insights into function they can provide remain unclear. Even for Caenorhabditis elegans, whose neuronal network is relatively small and stereotypical from animal to animal, published wiring diagrams are neither accurate nor complete and self-consistent. Using materials from White et al. and new electron micrographs we assemble whole, self-consistent gap junction and chemical synapse networks of hermaphrodite C. elegans. We propose a method to visualize the wiring diagram, which reflects network signal flow. We calculate statistical and topological properties of the network, such as degree distributions, synaptic multiplicities, and small-world properties, that help in understanding network signal propagation. We identify neurons that may play central roles in information processing, and network motifs that could serve as functional modules of the network. We explore propagation of neuronal activity in response to sensory or artificial stimulation using linear systems theory and find several activity patterns that could serve as substrates of previously described behaviors. Finally, we analyze the interaction between the gap junction and the chemical synapse networks. Since several statistical properties of the C. elegans network, such as multiplicity and motif distributions are similar to those found in mammalian neocortex, they likely point to general principles of neuronal networks. The wiring diagram reported here can help in understanding the mechanistic basis of behavior by generating predictions about future experiments involving genetic perturbations, laser ablations, or monitoring propagation of neuronal activity in response to stimulation.

  3. Structural properties of the Caenorhabditis elegans neuronal network.

    Directory of Open Access Journals (Sweden)

    Lav R Varshney

    Full Text Available Despite recent interest in reconstructing neuronal networks, complete wiring diagrams on the level of individual synapses remain scarce and the insights into function they can provide remain unclear. Even for Caenorhabditis elegans, whose neuronal network is relatively small and stereotypical from animal to animal, published wiring diagrams are neither accurate nor complete and self-consistent. Using materials from White et al. and new electron micrographs we assemble whole, self-consistent gap junction and chemical synapse networks of hermaphrodite C. elegans. We propose a method to visualize the wiring diagram, which reflects network signal flow. We calculate statistical and topological properties of the network, such as degree distributions, synaptic multiplicities, and small-world properties, that help in understanding network signal propagation. We identify neurons that may play central roles in information processing, and network motifs that could serve as functional modules of the network. We explore propagation of neuronal activity in response to sensory or artificial stimulation using linear systems theory and find several activity patterns that could serve as substrates of previously described behaviors. Finally, we analyze the interaction between the gap junction and the chemical synapse networks. Since several statistical properties of the C. elegans network, such as multiplicity and motif distributions are similar to those found in mammalian neocortex, they likely point to general principles of neuronal networks. The wiring diagram reported here can help in understanding the mechanistic basis of behavior by generating predictions about future experiments involving genetic perturbations, laser ablations, or monitoring propagation of neuronal activity in response to stimulation.

  4. Proteome changes of Caenorhabditis elegans upon a Staphylococcus aureus infection

    Directory of Open Access Journals (Sweden)

    Schoofs Liliane

    2010-02-01

    Full Text Available Abstract Background The success of invertebrates throughout evolution is an excellent illustration of the efficiency of their defence strategies. Caenorhabditis elegans has proven to be an appropriate model for transcriptome studies of host-pathogen interactions. The aim of this paper is to complement this knowledge by investigating the worm's response to a Staphylococcus aureus infection through a 2-dimensional differential proteomics approach. Results Different types of growth media in combination with either E. coli OP50 or Staphylococcus aureus were tested for an effect on the worm's lifespan. LB agar was chosen and C. elegans samples were collected 1 h, 4 h, 8 h and 24 h post S. aureus infection or E. coli incubation. Proteomics analyses resulted in the identification of 130 spots corresponding to a total of 108 differentially expressed proteins. Conclusions Exploring four time-points discloses a dynamic insight of the reaction against a gram-positive infection at the level of the whole organism. The remarkable upregulation after 8 h and 24 h of many enzymes involved in the citric acid cycle might illustrate the cost of fighting off an infection. Intriguing is the downregulation of chaperone molecules, which are presumed to serve a protective role. A comparison with a similar experiment in which C. elegans was infected with the gram-negative Aeromonas hydrophila reveals that merely 9% of the identified spots, some of which even exhibiting an opposite regulation, are present in both studies. Hence, our findings emphasise the complexity and pathogen-specificity of the worm's immune response and form a firm basis for future functional research. Reviewers This article was reviewed by Itai Yanai, Dieter Wolf and Torben Luebke (nominated by Walter Lutz.

  5. Polyamine-independent Expression of Caenorhabditis elegans Antizyme.

    Science.gov (United States)

    Stegehake, Dirk; Kurosinski, Marc-André; Schürmann, Sabine; Daniel, Jens; Lüersen, Kai; Liebau, Eva

    2015-07-17

    Degradation of ornithine decarboxylase, the rate-limiting enzyme of polyamine biosynthesis, is promoted by the protein antizyme. Expression of antizyme is positively regulated by rising polyamine concentrations that induce a +1 translational frameshift required for production of the full-length protein. Antizyme itself is negatively regulated by the antizyme inhibitor. In our study, the regulation of Caenorhabditis elegans antizyme was investigated, and the antizyme inhibitor was identified. By applying a novel GFP-based method to monitor antizyme frameshifting in vivo, we show that the induction of translational frameshifting also occurs under stressful conditions. Interestingly, during starvation, the initiation of frameshifting was independent of polyamine concentrations. Because frameshifting was also prevalent in a polyamine auxotroph double mutant, a polyamine-independent regulation of antizyme frameshifting is suggested. Polyamine-independent induction of antizyme expression was found to be negatively regulated by the peptide transporter PEPT-1, as well as the target of rapamycin, but not by the daf-2 insulin signaling pathway. Stress-dependent expression of C. elegans antizyme occurred morely slowly than expression in response to increased polyamine levels, pointing to a more general reaction to unfavorable conditions and a diversion away from proliferation and reproduction toward conservation of energy. Interestingly, antizyme expression was found to drastically increase in aging individuals in a postreproductive manner. Although knockdown of antizyme did not affect the lifespan of C. elegans, knockdown of the antizyme inhibitor led to a significant reduction in lifespan. This is most likely caused by an increase in antizyme-mediated degradation of ornithine decarboxylase-1 and a resulting reduction in cellular polyamine levels.

  6. Undulatory locomotion of finite filaments: lessons from Caenorhabditis elegans

    Science.gov (United States)

    Berman, R. S.; Kenneth, O.; Sznitman, J.; Leshansky, A. M.

    2013-07-01

    Undulatory swimming is a widespread propulsion strategy adopted by many small-scale organisms including various single-cell eukaryotes and nematodes. In this work, we report a comprehensive study of undulatory locomotion of a finite filament using (i) approximate resistive force theory (RFT) assuming a local nature of hydrodynamic interaction between the filament and the surrounding viscous liquid and (ii) particle-based numerical computations taking into account the intra-filament hydrodynamic interaction. Using the ubiquitous model of a propagating sinusoidal waveform, we identify the limit of applicability of the RFT and determine the optimal propulsion gait in terms of (i) swimming distance per period of undulation and (ii) hydrodynamic propulsion efficiency. The occurrence of the optimal swimming gait maximizing hydrodynamic efficiency at finite wavelength in particle-based computations diverges from the prediction of the RFT. To compare the model swimmer powered by sine wave undulations to biological undulatory swimmers, we apply the particle-based approach to study locomotion of the model organism nematode Caenorhabditis elegans using the swimming gait extracted from experiments. The analysis reveals that even though the amplitude and the wavenumber of undulations are similar to those determined for the best performing sinusoidal swimmer, C. elegans overperforms the latter in terms of both displacement and hydrodynamic efficiency. Further comparison with other undulatory microorganisms reveals that many adopt waveforms with characteristics similar to the optimal model swimmer, yet real swimmers still manage to beat the best performing sine-wave swimmer in terms of distance covered per period. Overall our results underline the importance of further waveform optimization, as periodic undulations adopted by C. elegans and other organisms deviate considerably from a simple sine wave.

  7. Phospholipase C-epsilon regulates epidermal morphogenesis in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Rafael P Vázquez-Manrique

    2008-03-01

    Full Text Available Migration of cells within epithelial sheets is an important feature of embryogenesis and other biological processes. Previous work has demonstrated a role for inositol 1,4,5-trisphosphate (IP(3-mediated calcium signalling in the rearrangement of epidermal cells (also known as hypodermal cells during embryonic morphogenesis in Caenorhabditis elegans. However the mechanism by which IP(3 production is stimulated is unknown. IP(3 is produced by the action of phospholipase C (PLC. We therefore surveyed the PLC family of C. elegans using RNAi and mutant strains, and found that depletion of PLC-1/PLC-epsilon produced substantial embryonic lethality. We used the epithelial cell marker ajm-1::gfp to follow the behaviour of epidermal cells and found that 96% of the arrested embryos have morphogenetic defects. These defects include defective ventral enclosure and aberrant dorsal intercalation. Using time-lapse confocal microscopy we show that the migration of the ventral epidermal cells, especially of the leading cells, is slower and often fails in plc-1(tm753 embryos. As a consequence plc-1 loss of function results in ruptured embryos with a Gex phenotype (gut on exterior and lumpy larvae. Thus PLC-1 is involved in the regulation of morphogenesis. Genetic studies using gain- and loss-of-function alleles of itr-1, the gene encoding the IP(3 receptor in C. elegans, demonstrate that PLC-1 acts through ITR-1. Using RNAi and double mutants to deplete the other PLCs in a plc-1 background, we show that PLC-3/PLC-gamma and EGL-8/PLC-beta can compensate for reduced PLC-1 activity. Our work places PLC-epsilon into a pathway controlling epidermal cell migration, thus establishing a novel role for PLC-epsilon.

  8. Biochemistry, function, and deficiency of vitamin B12 in Caenorhabditis elegans.

    Science.gov (United States)

    Bito, Tomohiro; Watanabe, Fumio

    2016-09-01

    Caenorhabditis elegans is a nematode that has been widely used as an animal for investigation of diverse biological phenomena. Vitamin B12 is essential for the growth of this worm, which contains two cobalamin-dependent enzymes, methylmalonyl-CoA mutase and methionine synthase. A full complement of gene homologs encoding the enzymes associated with the mammalian intercellular metabolic processes of vitamin B12 is identified in the genome of C elegans However, this worm has no orthologs of the vitamin B12-binders that participate in human intestinal absorption and blood circulation. When the worm is treated with a vitamin B12-deficient diet for five generations (15 days), it readily develops vitamin B12 deficiency, which induces worm phenotypes (infertility, delayed growth, and shorter lifespan) that resemble the symptoms of mammalian vitamin B12 deficiency. Such phenotypes associated with vitamin B12 deficiency were readily induced in the worm.

  9. The cellular and genetic basis of olfactory responses in Caenorhabditis elegans.

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    Sengupta, P; Colbert, H A; Kimmel, B E; Dwyer, N; Bargmann, C I

    1993-01-01

    The small soil nematode Caenorhabditis elegans has only 302 neurons in its entire nervous system, so it is possible to analyse the functions of individual neurons in the animal's behaviour. We are using behavioural, cellular and genetic analyses of chemotactic responses to find out how olfactory behaviour patterns are generated and regulated. Single chemosensory neurons in C. elegans can recognize several different attractive odorants that are distinguished by the animal. Distinct sets of chemosensory neurons detect high and low concentrations of a single odorant. Odorant responses adapt after prolonged exposure to an odorant; this adaptation is odorant specific and reversible. Mutants with defects in odorant responses have been identified. Some genes appear to be necessary for the development or function of particular kinds of sensory neurons. Other genes have effects that suggest that they participate in odorant reception or signal transduction.

  10. High-throughput in vivo analysis of gene expression in Caenorhabditis elegans.

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    Hunt-Newbury, Rebecca; Viveiros, Ryan; Johnsen, Robert; Mah, Allan; Anastas, Dina; Fang, Lily; Halfnight, Erin; Lee, David; Lin, John; Lorch, Adam; McKay, Sheldon; Okada, H Mark; Pan, Jie; Schulz, Ana K; Tu, Domena; Wong, Kim; Zhao, Z; Alexeyenko, Andrey; Burglin, Thomas; Sonnhammer, Eric; Schnabel, Ralf; Jones, Steven J; Marra, Marco A; Baillie, David L; Moerman, Donald G

    2007-09-01

    Using DNA sequences 5' to open reading frames, we have constructed green fluorescent protein (GFP) fusions and generated spatial and temporal tissue expression profiles for 1,886 specific genes in the nematode Caenorhabditis elegans. This effort encompasses about 10% of all genes identified in this organism. GFP-expressing wild-type animals were analyzed at each stage of development from embryo to adult. We have identified 5' DNA regions regulating expression at all developmental stages and in 38 different cell and tissue types in this organism. Among the regulatory regions identified are sequences that regulate expression in all cells, in specific tissues, in combinations of tissues, and in single cells. Most of the genes we have examined in C. elegans have human orthologs. All the images and expression pattern data generated by this project are available at WormAtlas (http://gfpweb.aecom.yu.edu/index) and through WormBase (http://www.wormbase.org).

  11. High-throughput in vivo analysis of gene expression in Caenorhabditis elegans.

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    Rebecca Hunt-Newbury

    2007-09-01

    Full Text Available Using DNA sequences 5' to open reading frames, we have constructed green fluorescent protein (GFP fusions and generated spatial and temporal tissue expression profiles for 1,886 specific genes in the nematode Caenorhabditis elegans. This effort encompasses about 10% of all genes identified in this organism. GFP-expressing wild-type animals were analyzed at each stage of development from embryo to adult. We have identified 5' DNA regions regulating expression at all developmental stages and in 38 different cell and tissue types in this organism. Among the regulatory regions identified are sequences that regulate expression in all cells, in specific tissues, in combinations of tissues, and in single cells. Most of the genes we have examined in C. elegans have human orthologs. All the images and expression pattern data generated by this project are available at WormAtlas (http://gfpweb.aecom.yu.edu/index and through WormBase (http://www.wormbase.org.

  12. NAD+ Is a Food Component That Promotes Exit from Dauer Diapause in Caenorhabditis elegans

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    Mylenko, Mykola; Boland, Sebastian; Penkov, Sider; Sampaio, Julio L.; Lombardot, Benoit; Vorkel, Daniela; Verbavatz, Jean-Marc; Kurzchalia, Teymuras V.

    2016-01-01

    The free-living soil nematode Caenorhabditis elegans adapts its development to the availability of food. When food is scarce and population density is high, worms enter a developmentally arrested non-feeding diapause stage specialized for long-term survival called the dauer larva. When food becomes available, they exit from the dauer stage, resume growth and reproduction. It has been postulated that compound(s) present in food, referred to as the “food signal”, promote exit from the dauer stage. In this study, we have identified NAD+ as a component of bacterial extract that promotes dauer exit. NAD+, when dissolved in alkaline medium, causes opening of the mouth and ingestion of food. We also show that to initiate exit from the dauer stage in response to NAD+ worms require production of serotonin. Thus, C. elegans can use redox cofactors produced by dietary organisms to sense food. PMID:27907064

  13. Roles for two partially redundant alpha-tubulins during mitosis in early Caenorhabditis elegans embryos.

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    Phillips, Jennifer B; Lyczak, Rebecca; Ellis, Gregory C; Bowerman, Bruce

    2004-06-01

    The Caenorhabditis elegans genome encodes multiple isotypes of alpha-tubulin and beta-tubulin. Roles for a number of these tubulins in neuronal development have been described, but less is known about the isoforms that function during early embryonic development. Microtubules are required for multiple events after fertilization produces a one-cell zygote in C. elegans, including pronuclear migration, mitotic spindle assembly and function, and proper spindle positioning. Here we describe a conditional and dominant mis-sense mutation in the C. elegans alpha-tubulin gene tba-1 that disrupts pronuclear migration and positioning of the first mitotic spindle, and results in a highly penetrant embryonic lethality, at the restrictive temperature of 26 degrees C. Our analysis of the dominant tba-1 (or346ts) allele suggests that TBA-1 assembles into microtubules in early embryonic cells. However, we also show that reduction of tba-1 function using RNA interference results in defects much less severe than those caused by the dominant or346ts mutation, due to partial redundancy of TBA-1 and another alpha-tubulin called TBA-2. Reducing the function of both TBA-1 and TBA-2 results in severe defects in microtubule-dependent processes. We conclude that microtubules in the early C. elegans embryo are composed of both TBA-1 and TBA-2, and that the dominant tba-1(or346ts) mutation disrupts MT assembly or stability. Cell Motil.

  14. Natural lignans from Arctium lappa as antiaging agents in Caenorhabditis elegans.

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    Su, Shan; Wink, Michael

    2015-09-01

    Arctium lappa is a well-known traditional medicinal plant in China (TCM) and Europe that has been used for thousands of years to treat arthritis, baldness or cancer. The plant produces lignans as secondary metabolites, which have a wide range of bioactivities. Yet, their antiaging potential has not been explored. In this study, we isolated six lignans from A. lappa seeds, namely arctigenin, matairesinol, arctiin, (iso)lappaol A, lappaol C, and lappaol F. The antioxidant and antiaging properties of the isolated lignans were studied using Caenorhabditis elegans as a relevant animal model. All lignans at concentrations of 10 and 100 μM significantly extended the mean life span of C. elegans. The strongest effect was observed with matairesinol, which at a concentration of 100 μM extended the life span of worms by 25%. Additionally, we observed that five lignans are strong free radical-scavengers in vitro and in vivo and all lignans can improve survival of C. elegans under oxidative stress. Furthermore, the lignans can induce the nuclear translocation of the transcription factor DAF-16 and up-regulate its expression, suggesting that a possible underlying mechanism of the observed longevity-promoting activity of lignans depends on DAF-16 mediated signaling pathway. All lignans up-regulated the expression of jnk-1, indicating that lignans may promote the C. elegans longevity and stress resistance through a JNK-1-DAF-16 cascade. Our study reports new antiaging activities of lignans, which might be candidates for developing antiaging agents.

  15. Agarose Microchambers for Long-term Calcium Imaging of Caenorhabditis elegans.

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    Turek, Michal; Besseling, Judith; Bringmann, Henrik

    2015-06-24

    Behavior is controlled by the nervous system. Calcium imaging is a straightforward method in the transparent nematode Caenorhabditis elegans to measure the activity of neurons during various behaviors. To correlate neural activity with behavior, the animal should not be immobilized but should be able to move. Many behavioral changes occur during long time scales and require recording over many hours of behavior. This also makes it necessary to culture the worms in the presence of food. How can worms be cultured and their neural activity imaged over long time scales? Agarose Microchamber Imaging (AMI) was previously developed to culture and observe small larvae and has now been adapted to study all life stages from early L1 until the adult stage of C. elegans. AMI can be performed on various life stages of C. elegans. Long-term calcium imaging is achieved without immobilizing the animals by using short externally triggered exposures combined with an electron multiplying charge-coupled device (EMCCD) camera recording. Zooming out or scanning can scale up this method to image up to 40 worms in parallel. Thus, a method is described to image behavior and neural activity over long time scales in all life stages of C. elegans.

  16. Gene expression changes of Caenorhabditis elegans larvae during molting and sleep-like lethargus.

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    Michal Turek

    Full Text Available During their development, Caenorhabditis elegans larvae go through four developmental stages. At the end of each larval stage, nematodes molt. They synthesize a new cuticle and shed the old cuticle. During the molt, larvae display a sleep-like behavior that is called lethargus. We wanted to determine how gene expression changes during the C. elegans molting cycle. We performed transcriptional profiling of C. elegans by selecting larvae displaying either sleep-like behavior during the molt or wake behavior during the intermolt to identify genes that oscillate with the molting-cycle. We found that expression changed during the molt and we identified 520 genes that oscillated with the molting cycle. 138 of these genes were not previously reported to oscillate. The majority of genes that had oscillating expression levels appear to be involved in molting, indicating that the majority of transcriptional changes serve to resynthesize the cuticle. Identification of genes that control sleep-like behavior during lethargus is difficult but may be possible by looking at genes that are expressed in neurons. 22 of the oscillating genes were expressed in neurons. One of these genes, the dopamine transporter gene dat-1, was previously shown in mammals and in C. elegans to control sleep. Taken together, we provide a dataset of genes that oscillate with the molting and sleep-wake cycle, which will be useful to investigate molting and possibly also sleep-like behavior during lethargus.

  17. Heterologous expression of functional G-protein-coupled receptors in Caenorhabditis elegans.

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    Salom, David; Cao, Pengxiu; Sun, Wenyu; Kramp, Kristopher; Jastrzebska, Beata; Jin, Hui; Feng, Zhaoyang; Palczewski, Krzysztof

    2012-02-01

    New strategies for expression, purification, functional characterization, and structural determination of membrane-spanning G-protein-coupled receptors (GPCRs) are constantly being developed because of their importance to human health. Here, we report a Caenorhabditis elegans heterologous expression system able to produce milligram amounts of functional native and engineered GPCRs. Both bovine opsin [(b)opsin] and human adenosine A(2A) subtype receptor [(h)A(2A)R] expressed in neurons or muscles of C. elegans were localized to cell membranes. Worms expressing these GPCRs manifested changes in motor behavior in response to light and ligands, respectively. With a newly devised protocol, 0.6-1 mg of purified homogenous 9-cis-retinal-bound bovine isorhodopsin [(b)isoRho] and ligand-bound (h)A(2A)R were obtained from C. elegans from one 10-L fermentation at low cost. Purified recombinant (b)isoRho exhibited its signature absorbance spectrum and activated its cognate G-protein transducin in vitro at a rate similar to native rhodopsin (Rho) obtained from bovine retina. Generally high expression levels of 11 native and mutant GPCRs demonstrated the potential of this C. elegans system to produce milligram quantities of high-quality GPCRs and possibly other membrane proteins suitable for detailed characterization.

  18. Chemosensory cue conditioning with stimulants in a Caenorhabditis elegans animal model of addiction.

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    Musselman, Heather N; Neal-Beliveau, Bethany; Nass, Richard; Engleman, Eric A

    2012-06-01

    The underlying molecular mechanisms of drug abuse and addiction behaviors are poorly understood. Caenorhabditis elegans (C. elegans) provide a simple, whole animal model with conserved molecular pathways well suited for studying the foundations of complex diseases. Historically, chemotaxis has been a measure used to examine sensory approach and avoidance behavior in worms. Chemotaxis can be modulated by previous experience, and cue-dependent conditioned learning has been demonstrated in C. elegans, but such conditioning with drugs of abuse has not been reported. Here we show that pairing a distinctive salt cue with a drug (cocaine or methamphetamine) results in a concentration-dependent change in preference for the cue that was paired with the drug during conditioning. Further, we demonstrate that pairing of either drug with a distinctive food type can also increase preference for the drug-paired food in the absence of the drug. Dopamine-deficient mutants did not develop drug-paired, cue-conditioned responses. The findings suggest that, like vertebrates, C. elegans display a conditioned preference for environments containing cues previously associated with drugs of abuse, and this response is dependent on dopamine neurotransmission. This model provides a new and powerful method to study the genetic and molecular mechanisms that mediate drug preference.

  19. Identifying Regulators of Morphogenesis Common to Vertebrate Neural Tube Closure and Caenorhabditis elegans Gastrulation.

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    Sullivan-Brown, Jessica L; Tandon, Panna; Bird, Kim E; Dickinson, Daniel J; Tintori, Sophia C; Heppert, Jennifer K; Meserve, Joy H; Trogden, Kathryn P; Orlowski, Sara K; Conlon, Frank L; Goldstein, Bob

    2016-01-01

    Neural tube defects including spina bifida are common and severe congenital disorders. In mice, mutations in more than 200 genes can result in neural tube defects. We hypothesized that this large gene set might include genes whose homologs contribute to morphogenesis in diverse animals. To test this hypothesis, we screened a set of Caenorhabditis elegans homologs for roles in gastrulation, a topologically similar process to vertebrate neural tube closure. Both C. elegans gastrulation and vertebrate neural tube closure involve the internalization of surface cells, requiring tissue-specific gene regulation, actomyosin-driven apical constriction, and establishment and maintenance of adhesions between specific cells. Our screen identified several neural tube defect gene homologs that are required for gastrulation in C. elegans, including the transcription factor sptf-3. Disruption of sptf-3 in C. elegans reduced the expression of early endodermally expressed genes as well as genes expressed in other early cell lineages, establishing sptf-3 as a key contributor to multiple well-studied C. elegans cell fate specification pathways. We also identified members of the actin regulatory WAVE complex (wve-1, gex-2, gex-3, abi-1, and nuo-3a). Disruption of WAVE complex members reduced the narrowing of endodermal cells' apical surfaces. Although WAVE complex members are expressed broadly in C. elegans, we found that expression of a vertebrate WAVE complex member, nckap1, is enriched in the developing neural tube of Xenopus. We show that nckap1 contributes to neural tube closure in Xenopus. This work identifies in vivo roles for homologs of mammalian neural tube defect genes in two manipulable genetic model systems.

  20. Chemically Defined Medium and Caenorhabditis elegans: A Powerful Approach

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    Szewczyk, N. J.; Kozak, E.; Conley, C. A.

    2003-01-01

    C. elegans has been established as a powerful genetic system. Growth in a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of me in large-scale growth and screening of animals. Here we present our initial results from developing culture systems with CeMM. We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats of using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change defined medium composition. As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  1. Paralysis and killing of Caenorhabditis elegans by enteropathogenic Escherichia coli requires the bacterial tryptophanase gene.

    Science.gov (United States)

    Anyanful, Akwasi; Dolan-Livengood, Jennifer M; Lewis, Taiesha; Sheth, Seema; Dezalia, Mark N; Sherman, Melanie A; Kalman, Lisa V; Benian, Guy M; Kalman, Daniel

    2005-08-01

    Pathogenic Escherichia coli, including enteropathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC) and enterotoxigenic E. coli (ETEC) are major causes of food and water-borne disease. We have developed a genetically tractable model of pathogenic E. coli virulence based on our observation that these bacteria paralyse and kill the nematode Caenorhabditis elegans. Paralysis and killing of C. elegans by EPEC did not require direct contact, suggesting that a secreted toxin mediates the effect. Virulence against C. elegans required tryptophan and bacterial tryptophanase, the enzyme catalysing the production of indole and other molecules from tryptophan. Thus, lack of tryptophan in growth media or deletion of tryptophanase gene failed to paralyse or kill C. elegans. While known tryptophan metabolites failed to complement an EPEC tryptophanase mutant when presented extracellularly, complementation was achieved with the enzyme itself expressed either within the pathogen or within a cocultured K12 strains. Thus, an unknown metabolite of tryptophanase, derived from EPEC or from commensal non-pathogenic strains, appears to directly or indirectly regulate toxin production within EPEC. EPEC strains containing mutations in the locus of enterocyte effacement (LEE), a pathogenicity island required for virulence in humans, also displayed attenuated capacity to paralyse and kill nematodes. Furthermore, tryptophanase activity was required for full activation of the LEE1 promoter, and for efficient formation of actin-filled membranous protrusions (attaching and effacing lesions) that form on the surface of mammalian epithelial cells following attachment and which depends on LEE genes. Finally, several C. elegans genes, including hif-1 and egl-9, rendered C. elegans less susceptible to EPEC when mutated, suggesting their involvement in mediating toxin effects. Other genes including sek-1, mek-1, mev-1, pgp-1,3 and vhl-1, rendered C. elegans more

  2. Angiotensin Converting Enzyme (ACE) Inhibitor Extends Caenorhabditis elegans Life Span.

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    Kumar, Sandeep; Dietrich, Nicholas; Kornfeld, Kerry

    2016-02-01

    Animal aging is characterized by progressive, degenerative changes in many organ systems. Because age-related degeneration is a major contributor to disability and death in humans, treatments that delay age-related degeneration are desirable. However, no drugs that delay normal human aging are currently available. To identify drugs that delay age-related degeneration, we used the powerful Caenorhabditis elegans model system to screen for FDA-approved drugs that can extend the adult lifespan of worms. Here we show that captopril extended mean lifespan. Captopril is an angiotensin-converting enzyme (ACE) inhibitor used to treat high blood pressure in humans. To explore the mechanism of captopril, we analyzed the acn-1 gene that encodes the C. elegans homolog of ACE. Reducing the activity of acn-1 extended the mean life span. Furthermore, reducing the activity of acn-1 delayed age-related degenerative changes and increased stress resistance, indicating that acn-1 influences aging. Captopril could not further extend the lifespan of animals with reduced acn-1, suggesting they function in the same pathway; we propose that captopril inhibits acn-1 to extend lifespan. To define the relationship with previously characterized longevity pathways, we analyzed mutant animals. The lifespan extension caused by reducing the activity of acn-1 was additive with caloric restriction and mitochondrial insufficiency, and did not require sir-2.1, hsf-1 or rict-1, suggesting that acn-1 functions by a distinct mechanism. The interactions with the insulin/IGF-1 pathway were complex, since the lifespan extensions caused by captopril and reducing acn-1 activity were additive with daf-2 and age-1 but required daf-16. Captopril treatment and reducing acn-1 activity caused similar effects in a wide range of genetic backgrounds, consistent with the model that they act by the same mechanism. These results identify a new drug and a new gene that can extend the lifespan of worms and suggest new

  3. Caenorhabditis elegans as a Model to Study the Molecular and Genetic Mechanisms of Drug Addiction.

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    Engleman, Eric A; Katner, Simon N; Neal-Beliveau, Bethany S

    2016-01-01

    Drug addiction takes a massive toll on society. Novel animal models are needed to test new treatments and understand the basic mechanisms underlying addiction. Rodent models have identified the neurocircuitry involved in addictive behavior and indicate that rodents possess some of the same neurobiologic mechanisms that mediate addiction in humans. Recent studies indicate that addiction is mechanistically and phylogenetically ancient and many mechanisms that underlie human addiction are also present in invertebrates. The nematode Caenorhabditis elegans has conserved neurobiologic systems with powerful molecular and genetic tools and a rapid rate of development that enables cost-effective translational discovery. Emerging evidence suggests that C. elegans is an excellent model to identify molecular mechanisms that mediate drug-induced behavior and potential targets for medications development for various addictive compounds. C. elegans emit many behaviors that can be easily quantitated including some that involve interactions with the environment. Ethanol (EtOH) is the best-studied drug-of-abuse in C. elegans and at least 50 different genes/targets have been identified as mediating EtOH's effects and polymorphisms in some orthologs in humans are associated with alcohol use disorders. C. elegans has also been shown to display dopamine and cholinergic system-dependent attraction to nicotine and demonstrate preference for cues previously associated with nicotine. Cocaine and methamphetamine have been found to produce dopamine-dependent reward-like behaviors in C. elegans. These behavioral tests in combination with genetic/molecular manipulations have led to the identification of dozens of target genes/systems in C. elegans that mediate drug effects. The one target/gene identified as essential for drug-induced behavioral responses across all drugs of abuse was the cat-2 gene coding for tyrosine hydroxylase, which is consistent with the role of dopamine neurotransmission

  4. Feeding behaviour of Caenorhabditis elegans is an indicator of Pseudomonas aeruginosa PAO1 virulence

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    Shawn Lewenza

    2014-08-01

    Full Text Available Caenorhabditis elegans is commonly used as an infection model for pathogenesis studies in Pseudomonas aeruginosa. The standard virulence assays rely on the slow and fast killing or paralysis of nematodes but here we developed a behaviour assay to monitor the preferred bacterial food sources of C. elegans. We monitored the food preferences of nematodes fed the wild type PAO1 and mutants in the type III secretion (T3S system, which is a conserved mechanism to inject secreted effectors into the host cell cytosol. A ΔexsEΔpscD mutant defective for type III secretion served as a preferred food source, while an ΔexsE mutant that overexpresses the T3S effectors was avoided. Both food sources were ingested and observed in the gastrointestinal tract. Using the slow killing assay, we showed that the ΔexsEΔpscD had reduced virulence and thus confirmed that preferred food sources are less virulent than the wild type. Next we developed a high throughput feeding behaviour assay with 48 possible food colonies in order to screen a transposon mutant library and identify potential virulence genes. C. elegans identified and consumed preferred food colonies from a grid of 48 choices. The mutants identified as preferred food sources included known virulence genes, as well as novel genes not identified in previous C. elegans infection studies. Slow killing assays were performed and confirmed that several preferred food sources also showed reduced virulence. We propose that C. elegans feeding behaviour can be used as a sensitive indicator of virulence for P. aeruginosa PAO1.

  5. Gene pathways that delay Caenorhabditis elegans reproductive senescence.

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    Meng C Wang

    2014-12-01

    Full Text Available Reproductive senescence is a hallmark of aging. The molecular mechanisms regulating reproductive senescence and its association with the aging of somatic cells remain poorly understood. From a full genome RNA interference (RNAi screen, we identified 32 Caenorhabditis elegans gene inactivations that delay reproductive senescence and extend reproductive lifespan. We found that many of these gene inactivations interact with insulin/IGF-1 and/or TGF-β endocrine signaling pathways to regulate reproductive senescence, except nhx-2 and sgk-1 that modulate sodium reabsorption. Of these 32 gene inactivations, we also found that 19 increase reproductive lifespan through their effects on oocyte activities, 8 of them coordinate oocyte and sperm functions to extend reproductive lifespan, and 5 of them can induce sperm humoral response to promote reproductive longevity. Furthermore, we examined the effects of these reproductive aging regulators on somatic aging. We found that 5 of these gene inactivations prolong organismal lifespan, and 20 of them increase healthy life expectancy of an organism without altering total life span. These studies provide a systemic view on the genetic regulation of reproductive senescence and its intersection with organism longevity. The majority of these newly identified genes are conserved, and may provide new insights into age-associated reproductive senescence during human aging.

  6. FAMILY OF FLP PEPTIDES IN CAENORHABDITIS ELEGANS AND RELATED NEMATODES

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    Chris eLi

    2014-10-01

    Full Text Available Neuropeptides regulate all aspects of behavior in multicellular organisms. Because of their ability to act at long distances, neuropeptides can exert their effects beyond the conventional synaptic connections, thereby adding an intricate layer of complexity to the activity of neural networks. In the nematode Caenorhabditis elegans, a large number of neuropeptide genes that are expressed throughout the nervous system has been identified. The actions of these peptides supplement the synaptic connections of the 302 neurons, allowing for fine tuning of neural networks and increasing the ways in which behaviors can be regulated. In this review, we focus on a large family of genes encoding FMRFamide-related peptides. These genes, the flp genes, have been used as a starting point to identifying flp genes throughout Nematoda. Nematodes have the largest family of FMRFamide-related peptides described thus far. The challenges in the future are the elucidation of their functions and the identification of the receptors and signaling pathways through which they function.

  7. Mitochondrial modulation of phosphine toxicity and resistance in Caenorhabditis elegans.

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    Zuryn, Steven; Kuang, Jujiao; Ebert, Paul

    2008-03-01

    Phosphine is a fumigant used to protect stored commodities from infestation by pest insects, though high-level phosphine resistance in many insect species threatens the continued use of the fumigant. The mechanisms of toxicity and resistance are not clearly understood. In this study, the model organism, Caenorhabditis elegans, was employed to investigate the effects of phosphine on its proposed in vivo target, the mitochondrion. We found that phosphine rapidly perturbs mitochondrial morphology, inhibits oxidative respiration by 70%, and causes a severe drop in mitochondrial membrane potential (DeltaPsim) within 5 h of exposure. We then examined the phosphine-resistant strain of nematode, pre-33, to determine whether resistance was associated with any changes to mitochondrial physiology. Oxygen consumption was reduced by 70% in these mutant animals, which also had more mitochondrial genome copies than wild-type animals, a common response to reduced metabolic capacity. The mutant also had an unexpected increase in the basal DeltaPsim, which protected individuals from collapse of the membrane potential following phosphine treatment. We tested whether directly manipulating mitochondrial function could influence sensitivity toward phosphine and found that suppression of mitochondrial respiratory chain genes caused up to 10-fold increase in phosphine resistance. The current study confirms that phosphine targets the mitochondria and also indicates that direct alteration of mitochondrial function may be related to phosphine resistance.

  8. A metabolic signature of long life in Caenorhabditis elegans

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    Viney Jonathan M

    2010-02-01

    Full Text Available Abstract Background Many Caenorhabditis elegans mutations increase longevity and much evidence suggests that they do so at least partly via changes in metabolism. However, up until now there has been no systematic investigation of how the metabolic networks of long-lived mutants differ from those of normal worms. Metabolomic technologies, that permit the analysis of many untargeted metabolites in parallel, now make this possible. Here we use one of these, 1H nuclear magnetic resonance spectroscopy, to investigate what makes long-lived worms metabolically distinctive. Results We examined three classes of long-lived worms: dauer larvae, adult Insulin/IGF-1 signalling (IIS-defective mutants, and a translation-defective mutant. Surprisingly, these ostensibly different long-lived worms share a common metabolic signature, dominated by shifts in carbohydrate and amino acid metabolism. In addition the dauer larvae, uniquely, had elevated levels of modified amino acids (hydroxyproline and phosphoserine. We interrogated existing gene expression data in order to integrate functional (metabolite-level changes with transcriptional changes at a pathway level. Conclusions The observed metabolic responses could be explained to a large degree by upregulation of gluconeogenesis and the glyoxylate shunt as well as changes in amino acid catabolism. These responses point to new possible mechanisms of longevity assurance in worms. The metabolic changes observed in dauer larvae can be explained by the existence of high levels of autophagy leading to recycling of cellular components. See associated minireview: http://jbiol.com/content/9/1/7

  9. Radiation effects on life span in Caenorhabditis elegans

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    Johnson, T.E.; Hartman, P.S.

    1988-09-01

    Wild-type and radiation-sensitive (Rad) mutants of Caenorhabditis elegans were irradiated using a /sup 137/Cs source (2.7 krads/min.) at several developmental stages and subsequently monitored for life span. Acute doses of radiation ranged from 1 krad to 300 krads. All stages required doses above 100 krads to reduce mean life span. Dauers and third stage larvae were more sensitive, and 8-day-old adults were the most resistant. Occasional statistically significant but nonrepeatable increases in survival were observed after intermediate levels of irradiation (10-30 krads). Unirradiated rad-4 and rad-7 had life spans similar to wild-type; all others had a significant reduction in survival. The mutants were about as sensitive as wild-type to the effects of ionizing radiation including occasional moderate life span extensions at intermediate doses. We conclude that the moderate life span extensions sometimes observed after irradiation are likely to be mediated by a means other than the induction of DNA repair enzymes.

  10. Sperm status regulates sexual attraction in Caenorhabditis elegans.

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    Morsci, Natalia S; Haas, Leonard A; Barr, Maureen M

    2011-12-01

    Mating behavior of animals is regulated by the sensory stimuli provided by the other sex. Sexually receptive females emit mating signals that can be inhibited by male ejaculate. The genetic mechanisms controlling the release of mating signals and encoding behavioral responses remain enigmatic. Here we present evidence of a Caenorhabditis elegans hermaphrodite-derived cue that stimulates male mating-response behavior and is dynamically regulated by her reproductive status. Wild-type males preferentially mated with older hermaphrodites. Increased sex appeal of older hermaphrodites was potent enough to stimulate robust response from mating-deficient pkd-2 and lov-1 polycystin mutant males. This enhanced response of pkd-2 males toward older hermaphrodites was independent of short-chain ascaroside pheromones, but was contingent on the absence of active sperm in the hermaphrodites. The improved pkd-2 male response toward spermless hermaphrodites was blocked by prior insemination or by genetic ablation of the ceh-18-dependent sperm-sensing pathway of the hermaphrodite somatic gonad. Our work suggests an interaction between sperm and the soma that has a negative but reversible effect on a hermaphrodite-derived mating cue that regulates male mating response, a phenomenon to date attributed to gonochoristic species only.

  11. Life Span and Motility Effects of Ethanolic Extracts from Sophora moorcroftiana Seeds on Caenorhabditis elegans

    Science.gov (United States)

    Li, Xin; Han, Junxian; Zhu, Rongyan; Cui, Rongrong; Ma, Xingming; Dong, Kaizhong

    2016-01-01

    Background: Sophora moorcroftiana is an endemic shrub species with a great value in folk medicine in Tibet, China. In this study, relatively little is known about whether S. moorcroftiana is beneficial in animals' nervous system and life span or not. Materials and Methods: To address this question, under survival normal temperature (25°C), S. moorcroftiana seeds were extracted with 95% ethanol, and Caenorhabditis elegans were exposed to three different extract concentrations (100 mg/L, 200 mg/L, and 400 mg/mL) from S. moorcroftiana seeds. Results: The 95% ethanolic extracts from S. moorcroftiana seeds could increase life span and slow aging-related increase in C. elegans and could not obviously influence the motility of C. elegans. Conclusion: Given these results by our experiment for life span and motility with 95% ethanolic extracts from S. moorcroftiana seeds in C. elegans, the question whether S. moorcroftiana acts as an anti-aging substance in vivo arises. SUMMARY The 95% ethanolic extracts from S. moorcroftiana seeds have no effect on the life span in C. elegans when extract concentrations from S. moorcroftiana seeds <400 mg/LThe 400 mg/L 95% ethanolic extracts from S. moorcroftiana seeds could increase life span in C. elegansThe 95% ethanolic extracts from S. moorcroftiana seeds could not obviously influence the motility in C. elegans. Abbreviation used: S. moorcroftiana: Sophora moorcroftiana; C. elegan: Caenorhabditis elegan; E. coli OP50: Escherichia coli OP50; DMSO: Dimethyl sulfoxide. PMID:27279712

  12. Phase transition in Caenorhabditis elegans: A classical oil-water phase separation?

    Science.gov (United States)

    Weber, Christoph; Tony Hyman Collaboration; Andrés Delgadillo Collaboration; Frank Jülicher Team

    2014-03-01

    In Caenorhabditis elegans droplets form before the cell divides. These droplets, also referred to as P-granules, consist of a variety of unstructured proteins and mRNA. Brangwynne et al. [Science, 2009] showed that the P-granules exhibit fluid-like behavior and that the phase separation is controlled spatially by a gradient of a component called Mex-5. It is believed that this system exhibits the same characteristics as a classical oil-water phase separation. Here we report the recent experimental investigations on the phase separation in Caenorhabditis elegans and compare our findings with a classical oil-water phase separation. Specifically, we consider the underlying coarsening mechanisms as well as the impact of temperature and species composition. Finally, we present a preliminary model incorporating the characteristics of the phase separation kinetics for Caenorhabditis elegans.

  13. Genome-wide analysis reveals novel genes essential for heme homeostasis in Caenorhabditis elegans.

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    Scott Severance

    2010-07-01

    Full Text Available Heme is a cofactor in proteins that function in almost all sub-cellular compartments and in many diverse biological processes. Heme is produced by a conserved biosynthetic pathway that is highly regulated to prevent the accumulation of heme--a cytotoxic, hydrophobic tetrapyrrole. Caenorhabditis elegans and related parasitic nematodes do not synthesize heme, but instead require environmental heme to grow and develop. Heme homeostasis in these auxotrophs is, therefore, regulated in accordance with available dietary heme. We have capitalized on this auxotrophy in C. elegans to study gene expression changes associated with precisely controlled dietary heme concentrations. RNA was isolated from cultures containing 4, 20, or 500 microM heme; derived cDNA probes were hybridized to Affymetrix C. elegans expression arrays. We identified 288 heme-responsive genes (hrgs that were differentially expressed under these conditions. Of these genes, 42% had putative homologs in humans, while genomes of medically relevant heme auxotrophs revealed homologs for 12% in both Trypanosoma and Leishmania and 24% in parasitic nematodes. Depletion of each of the 288 hrgs by RNA-mediated interference (RNAi in a transgenic heme-sensor worm strain identified six genes that regulated heme homeostasis. In addition, seven membrane-spanning transporters involved in heme uptake were identified by RNAi knockdown studies using a toxic heme analog. Comparison of genes that were positive in both of the RNAi screens resulted in the identification of three genes in common that were vital for organismal heme homeostasis in C. elegans. Collectively, our results provide a catalog of genes that are essential for metazoan heme homeostasis and demonstrate the power of C. elegans as a genetic animal model to dissect the regulatory circuits which mediate heme trafficking in both vertebrate hosts and their parasites, which depend on environmental heme for survival.

  14. Rendering the Intractable More Tractable: Tools from Caenorhabditis elegans Ripe for Import into Parasitic Nematodes.

    Science.gov (United States)

    Ward, Jordan D

    2015-12-01

    Recent and rapid advances in genetic and molecular tools have brought spectacular tractability to Caenorhabditis elegans, a model that was initially prized because of its simple design and ease of imaging. C. elegans has long been a powerful model in biomedical research, and tools such as RNAi and the CRISPR/Cas9 system allow facile knockdown of genes and genome editing, respectively. These developments have created an additional opportunity to tackle one of the most debilitating burdens on global health and food security: parasitic nematodes. I review how development of nonparasitic nematodes as genetic models informs efforts to import tools into parasitic nematodes. Current tools in three commonly studied parasites (Strongyloides spp., Brugia malayi, and Ascaris suum) are described, as are tools from C. elegans that are ripe for adaptation and the benefits and barriers to doing so. These tools will enable dissection of a huge array of questions that have been all but completely impenetrable to date, allowing investigation into host-parasite and parasite-vector interactions, and the genetic basis of parasitism.

  15. Zinc Levels Modulate Lifespan through Multiple Longevity Pathways in Caenorhabditis elegans.

    Science.gov (United States)

    Kumar, Jitendra; Barhydt, Tracy; Awasthi, Anjali; Lithgow, Gordon J; Killilea, David W; Kapahi, Pankaj

    2016-01-01

    Zinc is an essential trace metal that has integral roles in numerous biological processes, including enzymatic function, protein structure, and cell signaling pathways. Both excess and deficiency of zinc can lead to detrimental effects on development and metabolism, resulting in abnormalities and disease. We altered the zinc balance within Caenorhabditis elegans to examine how changes in zinc burden affect longevity and healthspan in an invertebrate animal model. We found that increasing zinc levels in vivo with excess dietary zinc supplementation decreased the mean and maximum lifespan, whereas reducing zinc levels in vivo with a zinc-selective chelator increased the mean and maximum lifespan in C. elegans. We determined that the lifespan shortening effects of excess zinc required expression of DAF-16, HSF-1 and SKN-1 proteins, whereas the lifespan lengthening effects of the reduced zinc may be partially dependent upon this set of proteins. Furthermore, reducing zinc levels led to greater nuclear localization of DAF-16 and enhanced dauer formation compared to controls, suggesting that the lifespan effects of zinc are mediated in part by the insulin/IGF-1 pathway. Additionally, zinc status correlated with several markers of healthspan in worms, including proteostasis, locomotion and thermotolerance, with reduced zinc levels always associated with improvements in function. Taken together, these data support a role for zinc in regulating both development and lifespan in C. elegans, and that suggest that regulation of zinc homeostasis in the worm may be an example of antagonistic pleiotropy.

  16. Caenorhabditis elegans: a model to investigate oxidative stress and metal dyshomeostasis in Parkinson’s disease

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    Patricia Mugure Chege

    2014-05-01

    Full Text Available Parkinson’s disease is characterized by progressive motor impairment attributed to progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Additional clinical manifestations include non-motor symptoms such as insomnia, depression, psychosis and cognitive impairment. Parkinson’s disease patients with mild cognitive impairment have an increased risk of developing dementia. The affected brain regions also show perturbed metal ion levels, primarily iron. These observations have led to speculation that metal ion dyshomeostasis plays a key role in the neuronal death of this disease. However, the mechanisms underlying this metal-associated neurodegeneration have yet to be completely elucidated.Mammalian models have traditionally been used to investigate Parkinson’s disease pathogenesis. However, alternate animal models are also being adopted, bringing to bear their respective experimental advantage. The nematode, Caenorhabditis elegans, is one such system that has well-developed genetics, is amenable to transgenesis and has relatively low associated experimental costs. C. elegans has a well characterised neuronal network that includes a simple dopaminergic system. In this review we will discuss mechanisms thought to underlie Parkinson’s disease and the use of C. elegans to investigate these processes.

  17. Zinc Levels Modulate Lifespan through Multiple Longevity Pathways in Caenorhabditis elegans

    Science.gov (United States)

    Kumar, Jitendra; Barhydt, Tracy; Awasthi, Anjali; Lithgow, Gordon J.; Killilea, David W.; Kapahi, Pankaj

    2016-01-01

    Zinc is an essential trace metal that has integral roles in numerous biological processes, including enzymatic function, protein structure, and cell signaling pathways. Both excess and deficiency of zinc can lead to detrimental effects on development and metabolism, resulting in abnormalities and disease. We altered the zinc balance within Caenorhabditis elegans to examine how changes in zinc burden affect longevity and healthspan in an invertebrate animal model. We found that increasing zinc levels in vivo with excess dietary zinc supplementation decreased the mean and maximum lifespan, whereas reducing zinc levels in vivo with a zinc-selective chelator increased the mean and maximum lifespan in C. elegans. We determined that the lifespan shortening effects of excess zinc required expression of DAF-16, HSF-1 and SKN-1 proteins, whereas the lifespan lengthening effects of the reduced zinc may be partially dependent upon this set of proteins. Furthermore, reducing zinc levels led to greater nuclear localization of DAF-16 and enhanced dauer formation compared to controls, suggesting that the lifespan effects of zinc are mediated in part by the insulin/IGF-1 pathway. Additionally, zinc status correlated with several markers of healthspan in worms, including proteostasis, locomotion and thermotolerance, with reduced zinc levels always associated with improvements in function. Taken together, these data support a role for zinc in regulating both development and lifespan in C. elegans, and that suggest that regulation of zinc homeostasis in the worm may be an example of antagonistic pleiotropy. PMID:27078872

  18. Caenorhabditis elegans as a simple model host for Vibrio vulnificus infection.

    Science.gov (United States)

    Dhakal, Bijaya Kumar; Lee, Wonhae; Kim, Young Ran; Choy, Hyon E; Ahnn, Joohong; Rhee, Joon Haeng

    2006-08-04

    Vibrio vulnificus is a human opportunistic pathogen which causes fatal septicemia and necrotic wound infection, resulting in a high mortality (over 50%). Caenorhabditis elegans has been studied as a model experimental host for V. vulnificus infection. V. vulnificus was shown to kill C. elegans effectively on different growth media and culture conditions. A marked reduction was observed in the life spans of worms when they were fed on V. vulnificus rather than on the ordinary laboratory food source, Escherichia coli OP50. The intestines of the C. elegans fed on V. vulnificus were grossly distended. In the C. elegans infection model, a V. vulnificus global virulence regulator CRP mutant and an exotoxin mutant exhibited significantly extended host killing duration. Here, we have shown that the virulence factors essential to mammalian V. vulnificus infections also play important roles in the killing of C. elegans, and thereby suggest that C. elegans is a favorable model for host-parasite interaction.

  19. Imaging ectopic fat deposition in Caenorhabditis elegans muscles using nonlinear microscopy.

    Science.gov (United States)

    Mari, Meropi; Filippidis, George; Palikaras, Konstantinos; Petanidou, Barbara; Fotakis, Costas; Tavernarakis, Nektarios

    2015-06-01

    The elucidation of the molecular mechanisms that lead to the development of metabolic syndrome, a complex of pathological conditions including type-2 diabetes, hypertension, and cardiovascular diseases, is an important issue with high biological significance and requires accurate methods capable of monitoring lipid storage distribution and dynamics in vivo. In this study, the nonlinear phenomena of second and third harmonic generation (SHG, THG) have been employed simultaneously as label-free, nondestructive diagnostic techniques, for the monitoring and the complementary three-dimensional (3D) imaging and analysis of the muscular areas and the lipid content localization. THG microscopy was used as a quantitative tool in order to record the accumulation of lipids in nonadipose tissues in the pharyngeal muscles of 18 Caenorhabditis elegans (C. elegans) specimens, while the SHG imaging provided the detailed anatomical information about the structure of the muscles. The ectopic accumulation of fat on the pharyngeal muscles increases in wild-type (N2) C. elegans between 1 and 9 days of adulthood. This suggests a correlation of ectopic fat accumulation with the process of aging. Our results can contribute to the unraveling of the link between the deposition of ectopic fat and aging, but mainly to the validation of SHG and THG microscopy modalities as new, noninvasive tools to localize and quantify selectively lipid formation and distribution.

  20. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D

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    Tong Young Lee

    2016-04-01

    Full Text Available The nematode Caenorhabditis elegans is one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however, C. elegans is found in three dimensional environments such as rotting fruit. To investigate the biology of C. elegans in a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory.

  1. Impact of a Complex Food Microbiota on Energy Metabolism in the Model Organism Caenorhabditis elegans

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    Elena Zanni

    2015-01-01

    Full Text Available The nematode Caenorhabditis elegans is widely used as a model system for research on aging, development, and host-pathogen interactions. Little is currently known about the mechanisms underlying the effects exerted by foodborne microbes. We took advantage of C. elegans to evaluate the impact of foodborne microbiota on well characterized physiological features of the worms. Foodborne lactic acid bacteria (LAB consortium was used to feed nematodes and its composition was evaluated by 16S rDNA analysis and strain typing before and after colonization of the nematode gut. Lactobacillus delbrueckii, L. fermentum, and Leuconostoc lactis were identified as the main species and shown to display different worm gut colonization capacities. LAB supplementation appeared to decrease nematode lifespan compared to the animals fed with the conventional Escherichia coli nutrient source or a probiotic bacterial strain. Reduced brood size was also observed in microbiota-fed nematodes. Moreover, massive accumulation of lipid droplets was revealed by BODIPY staining. Altered expression of nhr-49, pept-1, and tub-1 genes, associated with obesity phenotypes, was demonstrated by RT-qPCR. Since several pathways are evolutionarily conserved in C. elegans, our results highlight the nematode as a valuable model system to investigate the effects of a complex microbial consortium on host energy metabolism.

  2. Impact of a Complex Food Microbiota on Energy Metabolism in the Model Organism Caenorhabditis elegans.

    Science.gov (United States)

    Zanni, Elena; Laudenzi, Chiara; Schifano, Emily; Palleschi, Claudio; Perozzi, Giuditta; Uccelletti, Daniela; Devirgiliis, Chiara

    2015-01-01

    The nematode Caenorhabditis elegans is widely used as a model system for research on aging, development, and host-pathogen interactions. Little is currently known about the mechanisms underlying the effects exerted by foodborne microbes. We took advantage of C. elegans to evaluate the impact of foodborne microbiota on well characterized physiological features of the worms. Foodborne lactic acid bacteria (LAB) consortium was used to feed nematodes and its composition was evaluated by 16S rDNA analysis and strain typing before and after colonization of the nematode gut. Lactobacillus delbrueckii, L. fermentum, and Leuconostoc lactis were identified as the main species and shown to display different worm gut colonization capacities. LAB supplementation appeared to decrease nematode lifespan compared to the animals fed with the conventional Escherichia coli nutrient source or a probiotic bacterial strain. Reduced brood size was also observed in microbiota-fed nematodes. Moreover, massive accumulation of lipid droplets was revealed by BODIPY staining. Altered expression of nhr-49, pept-1, and tub-1 genes, associated with obesity phenotypes, was demonstrated by RT-qPCR. Since several pathways are evolutionarily conserved in C. elegans, our results highlight the nematode as a valuable model system to investigate the effects of a complex microbial consortium on host energy metabolism.

  3. Elemental bioimaging of Cisplatin in Caenorhabditis elegans by LA-ICP-MS

    Science.gov (United States)

    Crone, Barbara; Aschner, Michael; Schwerdtle, Tanja; Karst, Uwe; Bornhorst, Julia

    2015-01-01

    Cis-diamminedichloroplatinum(II) (Cisplatin) is one of the most important and frequently used cytostatic drugs for the treatment of various solid tumors. Herein, a laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method incorporating a fast and simple sample preparation protocol was developed for the elemental mapping of Cisplatin in the model organism Caenorhabditis elegans (C. elegans). The method allows imaging of the spatially-resolved elemental distribution of platinum in the whole organism with respect to the anatomic structure in L4 stage worms at a lateral resolution of 5 µm. In addition, a dose- and time-dependent Cisplatin uptake was corroborated quantitatively by a total reflection X-ray fluorescence spectroscopy (TXRF) method, and the elemental mapping indicated that Cisplatin is located in the intestine and in the head of the worms. Better understanding of the distribution of Cisplatin in this well-established model organism will be instrumental in deciphering Cisplatin toxicity and pharmacokinetics. Since the cytostatic effect of Cisplatin is based on binding the DNA by forming intra- and interstrand crosslinks, the response of poly(ADP-ribose)metabolism enzyme 1 (pme-1) deletion mutants to Cisplatin was also examined. Loss of pme-1, which is the C. elegans ortholog of human poly(ADP-ribose) polymerase 1 (PARP-1) led to disturbed DNA damage response. With respect to survival and brood size, pme-1 deletion mutants were more sensitive to Cisplatin as compared to wildtype worms, while Cisplatin uptake was indistinguishable. PMID:25996669

  4. Selection of reliable reference genes in Caenorhabditis elegans for analysis of nanotoxicity.

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    Yanqiong Zhang

    Full Text Available Despite rapid development and application of a wide range of manufactured metal oxide nanoparticles (NPs, the understanding of potential risks of using NPs is less completed, especially at the molecular level. The nematode Caenorhabditis elegans (C.elegans has been emerging as an environmental model to study the molecular mechanism of environmental contaminations, using standard genetic tools such as the real-time quantitative PCR (RT-qPCR. The most important factor that may affect the accuracy of RT-qPCR is to choose appropriate genes for normalization. In this study, we selected 13 reference gene candidates (act-1, cdc-42, pmp-3, eif-3.C, actin, act-2, csq-1, Y45F10D.4, tba-1, mdh-1, ama-1, F35G12.2, and rbd-1 to test their expression stability under different doses of nano-copper oxide (CuO 0, 1, 10, and 50 µg/mL using RT-qPCR. Four algorithms, geNorm, NormFinder, BestKeeper, and the comparative ΔCt method, were employed to evaluate these 13 candidates expressions. As a result, tba-1, Y45F10D.4 and pmp-3 were the most reliable, which may be used as reference genes in future study of nanoparticle-induced genetic response using C.elegans.

  5. NGT-3D: a simple nematode cultivation system to study Caenorhabditis elegans biology in 3D

    Science.gov (United States)

    Lee, Tong Young; Yoon, Kyoung-hye; Lee, Jin Il

    2016-01-01

    ABSTRACT The nematode Caenorhabditis elegans is one of the premier experimental model organisms today. In the laboratory, they display characteristic development, fertility, and behaviors in a two dimensional habitat. In nature, however, C. elegans is found in three dimensional environments such as rotting fruit. To investigate the biology of C. elegans in a 3D controlled environment we designed a nematode cultivation habitat which we term the nematode growth tube or NGT-3D. NGT-3D allows for the growth of both nematodes and the bacteria they consume. Worms show comparable rates of growth, reproduction and lifespan when bacterial colonies in the 3D matrix are abundant. However, when bacteria are sparse, growth and brood size fail to reach levels observed in standard 2D plates. Using NGT-3D we observe drastic deficits in fertility in a sensory mutant in 3D compared to 2D, and this defect was likely due to an inability to locate bacteria. Overall, NGT-3D will sharpen our understanding of nematode biology and allow scientists to investigate questions of nematode ecology and evolutionary fitness in the laboratory. PMID:26962047

  6. Caenorhabditis elegans SOS-1 is necessary for multiple RAS-mediated developmental signals

    Science.gov (United States)

    Chang, Chieh; Hopper, Neil A.; Sternberg, Paul W.

    2000-01-01

    Vulval induction in Caenorhabditis elegans has helped define an evolutionarily conserved signal transduction pathway from receptor tyrosine kinases (RTKs) through the adaptor protein SEM-5 to RAS. One component present in other organisms, a guanine nucleotide exchange factor for Ras, has been missing in C.elegans. To understand the regulation of this pathway it is crucial to have all positive-acting components in hand. Here we describe the identification, cloning and genetic characterization of C.elegans SOS-1, a putative guanine nucleotide exchanger for LET-60 RAS. RNA interference experiments suggest that SOS-1 participates in RAS-dependent signaling events downstream of LET-23 EGFR, EGL-15 FGFR and an unknown RTK. We demonstrate that the previously identified let-341 gene encodes SOS-1. Analyzing vulval development in a let-341 null mutant, we find an SOS-1-independent pathway involved in the activation of RAS signaling. This SOS-1-independent signaling is not inhibited by SLI-1/Cbl and is not mediated by PTP-2/SHP, raising the possibility that there could be another RasGEF. PMID:10880441

  7. A potent dauer pheromone component in Caenorhabditis elegans that acts synergistically with other components.

    Science.gov (United States)

    Butcher, Rebecca A; Ragains, Justin R; Kim, Edward; Clardy, Jon

    2008-09-23

    In the model organism Caenorhabditis elegans, the dauer pheromone is the primary cue for entry into the developmentally arrested, dauer larval stage. The dauer is specialized for survival under harsh environmental conditions and is considered "nonaging" because larvae that exit dauer have a normal life span. C. elegans constitutively secretes the dauer pheromone into its environment, enabling it to sense its population density. Several components of the dauer pheromone have been identified as derivatives of the dideoxy sugar ascarylose, but additional unidentified components of the dauer pheromone contribute to its activity. Here, we show that an ascaroside with a 3-hydroxypropionate side chain is a highly potent component of the dauer pheromone that acts synergistically with previously identified components. Furthermore, we show that the active dauer pheromone components that are produced by C. elegans vary depending on cultivation conditions. Identifying the active components of the dauer pheromone, the conditions under which they are produced, and their mechanisms of action will greatly extend our understanding of how chemosensory cues from the environment can influence such fundamental processes as development, metabolism, and aging in nematodes and in higher organisms.

  8. Using Caenorhabditis elegans to Uncover Conserved Functions of Omega-3 and Omega-6 Fatty Acids

    OpenAIRE

    Watts, Jennifer L.

    2016-01-01

    The nematode Caenorhabditis elegans is a powerful model organism to study functions of polyunsaturated fatty acids. The ability to alter fatty acid composition with genetic manipulation and dietary supplementation permits the dissection of the roles of omega-3 and omega-6 fatty acids in many biological process including reproduction, aging and neurobiology. Studies in C. elegans to date have mostly identified overlapping functions of 20-carbon omega-6 and omega-3 fatty acids in reproduction a...

  9. A conserved checkpoint monitors meiotic chromosome synapsis inCaenorhabditis elegans

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    Bhalla, Needhi; Dernburg, Abby F.

    2005-07-14

    We report the discovery of a checkpoint that monitorssynapsis between homologous chromosomes to ensure accurate meioticsegregation. Oocytes containing unsynapsed chromosomes selectivelyundergo apoptosis even if agermline DNA damage checkpoint is inactivated.This culling mechanism isspecifically activated by unsynapsed pairingcenters, cis-acting chromosomesites that are also required to promotesynapsis in Caenorhabditis elegans. Apoptosis due to synaptic failurealso requires the C. elegans homolog of PCH2,a budding yeast pachytenecheckpoint gene, which suggests that this surveillance mechanism iswidely conserved.

  10. Communication between oocytes and somatic cells regulates volatile pheromone production in Caenorhabditis elegans

    OpenAIRE

    Leighton, Daniel H. W.; Choe, Andrea; Wu, Shannon Y; Sternberg, Paul W.

    2014-01-01

    Males of the androdioecious species Caenorhabditis elegans are more likely to attempt to mate with and successfully inseminate C. elegans hermaphrodites that do not concurrently harbor sperm. Although a small number of genes have been implicated in this effect, the mechanism by which it arises remains unknown. In the context of the battle of the sexes, it is also unknown whether this effect is to the benefit of the male, the hermaphrodite, or both. We report that successful contact between ma...

  11. Propulsion by sinusoidal locomotion: A motion inspired by Caenorhabditis elegans

    Science.gov (United States)

    Ulrich, Xialing

    Sinusoidal locomotion is commonly seen in snakes, fish, nematodes, or even the wings of some birds and insects. This doctoral thesis presents the study of sinusoidal locomotion of the nematode C. elegans in experiments and the application of the state-space airloads theory to the theoretical forces of sinusoidal motion. An original MATLAB program has been developed to analyze the video records of C. elegans' movement in different fluids, including Newtonian and non-Newtonian fluids. The experimental and numerical studies of swimming C. elegans has revealed three conclusions. First, though the amplitude and wavelength are varying with time, the motion of swimming C. elegans can still be viewed as sinusoidal locomotion with slips. The average normalized wavelength is a conserved character of the locomotion for both Newtonian and non-Newtonian fluids. Second, fluid viscosity affects the frequency but not the moving speed of C. elegans, while fluid elasticity affects the moving speed but not the frequency. Third, by the resistive force theory, for more elastic fluids the ratio of resistive coefficients becomes smaller. Inspired by the motion of C. elegans and other animals performing sinusoidal motion, we investigated the sinusoidal motion of a thin flexible wing in theory. Given the equation of the motion, we have derived the closed forms of propulsive force, lift and other generalized forces applying on the wing. We also calculated the power required to perform the motion, the power lost due to the shed vortices and the propulsive efficiency. These forces and powers are given as functions of reduced frequency k, dimensionless wavelength z, dimensionless amplitude A/b, and time. Our results show that a positive, time-averaged propulsive force is produced for all k>k0=pi/ z. At k=k0, which implies the moment when the moving speed of the wing is the same as the wave speed of its undulation, the motion reaches a steady state with all forces being zero. If there were no

  12. WormScan: a technique for high-throughput phenotypic analysis of Caenorhabditis elegans.

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    Mark D Mathew

    Full Text Available BACKGROUND: There are four main phenotypes that are assessed in whole organism studies of Caenorhabditis elegans; mortality, movement, fecundity and size. Procedures have been developed that focus on the digital analysis of some, but not all of these phenotypes and may be limited by expense and limited throughput. We have developed WormScan, an automated image acquisition system that allows quantitative analysis of each of these four phenotypes on standard NGM plates seeded with E. coli. This system is very easy to implement and has the capacity to be used in high-throughput analysis. METHODOLOGY/PRINCIPAL FINDINGS: Our system employs a readily available consumer grade flatbed scanner. The method uses light stimulus from the scanner rather than physical stimulus to induce movement. With two sequential scans it is possible to quantify the induced phototactic response. To demonstrate the utility of the method, we measured the phenotypic response of C. elegans to phosphine gas exposure. We found that stimulation of movement by the light of the scanner was equivalent to physical stimulation for the determination of mortality. WormScan also provided a quantitative assessment of health for the survivors. Habituation from light stimulation of continuous scans was similar to habituation caused by physical stimulus. CONCLUSIONS/SIGNIFICANCE: There are existing systems for the automated phenotypic data collection of C. elegans. The specific advantages of our method over existing systems are high-throughput assessment of a greater range of phenotypic endpoints including determination of mortality and quantification of the mobility of survivors. Our system is also inexpensive and very easy to implement. Even though we have focused on demonstrating the usefulness of WormScan in toxicology, it can be used in a wide range of additional C. elegans studies including lifespan determination, development, pathology and behavior. Moreover, we have even adapted the

  13. Dietary restriction of Caenorhabditis elegans by axenic culture reflects nutritional requirement for constituents provided by metabolically active microbes.

    Science.gov (United States)

    Lenaerts, Isabelle; Walker, Glenda A; Van Hoorebeke, Luc; Gems, David; Vanfleteren, Jacques R

    2008-03-01

    In Caenorhabditis elegans, several manipulations that affect nutrition slow development, reduce fecundity, and increase life span. These are viewed as dietary restriction (DR) and include culture in semidefined, nutrient-rich liquid medium that is axenic (i.e., there is no microbial food source). Here we describe convenient ways to exert DR by culture on agar plates containing axenic medium. We used these to explore whether effects of axenic culture really reflect DR. Our results imply that major nutrient components of axenic medium, and overall caloric content, are not limiting for life span. However, adding growth-arrested Escherichia coli as an additional food source rescued the effects of axenic culture. We then sought to identify the component of E. coli that is critical for normal C. elegans nutrition using add-back experiments. Our results suggest that C. elegans has a nutritional requirement for live, metabolically active microbes or, possibly, an unidentified, heat-labile, nonsoluble component present in live microbes.

  14. The effects of translocations on recombination frequency in Caenorhabditis elegans.

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    McKim, K S; Howell, A M; Rose, A M

    1988-12-01

    In the nematode Caenorhabditis elegans, recombination suppression in translocation heterozygotes is severe and extensive. We have examined the meiotic properties of two translocations involving chromosome I, szT1(I;X) and hT1(I;V). No recombination was observed in either of these translocation heterozygotes along the left (let-362-unc-13) 17 map units of chromosome I. Using half-translocations as free duplications, we mapped the breakpoints of szT1 and hT1. The boundaries of crossover suppression coincided with the physical breakpoints. We propose that DNA sequences at the right end of chromosome I facilitate pairing and recombination. We use the data from translocations of other chromosomes to map the location of pairing sites on four other chromosomes. hT1 and szT1 differed markedly in their effect on recombination adjacent to the crossover suppressed region. hT1 had no effect on recombination in the adjacent interval. In contrast, the 0.8 map unit interval immediately adjacent to the szT1(I;X) breakpoint on chromosome I increased to 2.5 map units in translocation heterozygotes. This increase occurs in a chromosomal interval which can be expanded by treatment with radiation. These results are consistent with the suggestion that the szT1(I) breakpoint is in a region of DNA in which meiotic recombination is suppressed relative to the genomic average. We propose that DNA sequences disrupted by the szT1 translocation are responsible for determining the frequency of meiotic recombination in the vicinity of the breakpoint.

  15. Oxidative Stress in Caenorhabditis elegans: Protective Effects of Spartin.

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    Timothy Truong

    Full Text Available Troyer syndrome is caused by a mutation in the SPG20 gene, which results in complete loss of expression of the protein spartin. We generated a genetic model of Troyer syndrome in worms to explore the locomotor consequences of a null mutation of the Caenorhabditis elegans SPG20 orthologue, F57B10.9, also known as spg-20. Spg-20 mutants showed decreased length, crawling speed, and thrashing frequency, and had a shorter lifespan than wild-type animals. These results suggest an age-dependent decline in motor function in mutant animals. The drug paraquat was used to induce oxidative stress for 4 days in the animals. We measured survival rate and examined locomotion by measuring crawling speed and thrashing frequency. After 4 days of paraquat exposure, 77% of wild-type animals survived, but only 38% of spg-20 mutant animals survived. Conversely, animals overexpressing spg-20 had a survival rate of 95%. We also tested lifespan after a 1 hour exposure to sodium azide. After a 24 hour recovery period, 87% of wild type animals survived, 57% of spg-20 mutant animals survived, and 82% of animals overexpressing spg-20 survived. In the behavioral assays, spg-20 mutant animals showed a significant decrease in both crawling speed and thrashing frequency compared with wild-type animals. Importantly, the locomotor phenotype for both crawling and thrashing was rescued in animals overexpressing spg-20. The animals overexpressing spg-20 had crawling speeds and thrashing frequencies similar to those of wild-type animals. These data suggest that the protein F57B10.9/SPG-20 might have a protective role against oxidative stress.

  16. Mesoscopic organization reveals the constraints governing Caenorhabditis elegans nervous system.

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    Raj Kumar Pan

    Full Text Available One of the biggest challenges in biology is to understand how activity at the cellular level of neurons, as a result of their mutual interactions, leads to the observed behavior of an organism responding to a variety of environmental stimuli. Investigating the intermediate or mesoscopic level of organization in the nervous system is a vital step towards understanding how the integration of micro-level dynamics results in macro-level functioning. The coordination of many different co-occurring processes at this level underlies the command and control of overall network activity. In this paper, we have considered the somatic nervous system of the nematode Caenorhabditis elegans, for which the entire neuronal connectivity diagram is known. We focus on the organization of the system into modules, i.e., neuronal groups having relatively higher connection density compared to that of the overall network. We show that this mesoscopic feature cannot be explained exclusively in terms of considerations such as, optimizing for resource constraints (viz., total wiring cost and communication efficiency (i.e., network path length. Even including information about the genetic relatedness of the cells cannot account for the observed modular structure. Comparison with other complex networks designed for efficient transport (of signals or resources implies that neuronal networks form a distinct class. This suggests that the principal function of the network, viz., processing of sensory information resulting in appropriate motor response, may be playing a vital role in determining the connection topology. Using modular spectral analysis we make explicit the intimate relation between function and structure in the nervous system. This is further brought out by identifying functionally critical neurons purely on the basis of patterns of intra- and inter-modular connections. Our study reveals how the design of the nervous system reflects several constraints, including

  17. Identification of DVA interneuron regulatory sequences in Caenorhabditis elegans.

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    Carmie Puckett Robinson

    Full Text Available BACKGROUND: The identity of each neuron is determined by the expression of a distinct group of genes comprising its terminal gene battery. The regulatory sequences that control the expression of such terminal gene batteries in individual neurons is largely unknown. The existence of a complete genome sequence for C. elegans and draft genomes of other nematodes let us use comparative genomics to identify regulatory sequences directing expression in the DVA interneuron. METHODOLOGY/PRINCIPAL FINDINGS: Using phylogenetic comparisons of multiple Caenorhabditis species, we identified conserved non-coding sequences in 3 of 10 genes (fax-1, nmr-1, and twk-16 that direct expression of reporter transgenes in DVA and other neurons. The conserved region and flanking sequences in an 85-bp intronic region of the twk-16 gene directs highly restricted expression in DVA. Mutagenesis of this 85 bp region shows that it has at least four regions. The central 53 bp region contains a 29 bp region that represses expression and a 24 bp region that drives broad neuronal expression. Two short flanking regions restrict expression of the twk-16 gene to DVA. A shared GA-rich motif was identified in three of these genes but had opposite effects on expression when mutated in the nmr-1 and twk-16 DVA regulatory elements. CONCLUSIONS/SIGNIFICANCE: We identified by multi-species conservation regulatory regions within three genes that direct expression in the DVA neuron. We identified four contiguous regions of sequence of the twk-16 gene enhancer with positive and negative effects on expression, which combined to restrict expression to the DVA neuron. For this neuron a single binding site may thus not achieve sufficient specificity for cell specific expression. One of the positive elements, an 8-bp sequence required for expression was identified in silico by sequence comparisons of seven nematode species, demonstrating the potential resolution of expanded multi

  18. Abl kinase inhibits the engulfment of apoptotic [corrected] cells in Caenorhabditis elegans.

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    Michael E Hurwitz

    2009-04-01

    Full Text Available The engulfment of apoptotic cells is required for normal metazoan development and tissue remodeling. In Caenorhabditis elegans, two parallel and partially redundant conserved pathways act in cell-corpse engulfment. One pathway includes the adaptor protein CED-2 CrkII and the small GTPase CED-10 Rac, and acts to rearrange the cytoskeleton of the engulfing cell. The other pathway includes the receptor tyrosine kinase CED-1 and might recruit membranes to extend the surface of the engulfing cell. Although many components required for engulfment have been identified, little is known about inhibition of engulfment. The tyrosine kinase Abl regulates the actin cytoskeleton in mammals and Drosophila in multiple ways. For example, Abl inhibits cell migration via phosphorylation of CrkII. We tested whether ABL-1, the C. elegans ortholog of Abl, inhibits the CED-2 CrkII-dependent engulfment of apoptotic cells. Our genetic studies indicate that ABL-1 inhibits apoptotic cell engulfment, but not through CED-2 CrkII, and instead acts in parallel to the two known engulfment pathways. The CED-10 Rac pathway is also required for proper migration of the distal tip cells (DTCs during the development of the C. elegans gonad. The loss of ABL-1 function partially restores normal DTC migration in the CED-10 Rac pathway mutants. We found that ABI-1 the C. elegans homolog of mammalian Abi (Abl interactor proteins, is required for engulfment of apoptotic cells and proper DTC migration. Like Abl, Abi proteins are cytoskeletal regulators. ABI-1 acts in parallel to the two known engulfment pathways, likely downstream of ABL-1. ABL-1 and ABI-1 interact physically in vitro. We propose that ABL-1 opposes the engulfment of apoptotic cells by inhibiting ABI-1 via a pathway that is distinct from the two known engulfment pathways.

  19. Two Neuronal G Proteins Are Involved in Chemosensation of the Caenorhabditis Elegans Dauer-Inducing Pheromone

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    Zwaal, R. R.; Mendel, J. E.; Sternberg, P. W.; Plasterk, RHA.

    1997-01-01

    Caenorhabditis elegans uses chemosensation to determine its course of development. Young larvae can arrest as dauer larvae in response to increasing population density, which they measure by a nematode-excreted pheromone, and decreasing food supply. Dauer larvae can resume development in response to a decrease in pheromone and increase in food concentration. We show here that two novel G protein alpha subunits (GPA-2 and GPA-3) show promoter activity in subsets of chemosensory neurons and are involved in the decision to form dauer larvae primarily through the response to dauer pheromone. Dominant activating mutations in these G proteins result in constitutive, pheromone-independent dauer formation, whereas inactivation results in reduced sensitivity to pheromone, and, under certain conditions, an alteration in the response to food. Interactions between gpa-2, gpa-3 and other genes controlling dauer formation suggest that these G proteins may act in parallel to regulate the neuronal decision making that precedes dauer formation. PMID:9055081

  20. Caenorhabditis elegans DAF-2 as a Model for Human Insulin Receptoropathies

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    David A. Bulger

    2017-01-01

    Full Text Available Human exome sequencing has dramatically increased the rate of identification of disease-associated polymorphisms. However, examining the functional consequences of those variants has created an analytic bottleneck. Insulin-like signaling in Caenorhabditis elegans has long provided a model to assess consequences of human insulin signaling mutations, but this has not been evaluated in the context of current genetic tools. We have exploited strains derived from the Million Mutation Project (MMP and gene editing to explore further the evolutionary relationships and conservation between the human and C. elegans insulin receptors. Of 40 MMP alleles analyzed in the C. elegans insulin-like receptor gene DAF-2, 35 exhibited insulin-like signaling indistinguishable from wild-type animals, indicating tolerated mutations. Five MMP alleles proved to be novel dauer-enhancing mutations, including one new allele in the previously uncharacterized C-terminus of DAF-2. CRISPR-Cas9 genome editing was used to confirm the phenotypic consequence of six of these DAF-2 mutations and to replicate an allelic series of known human disease mutations in a highly conserved tyrosine kinase active site residue, demonstrating the utility of C. elegans for directly modeling human disease. Our results illustrate the challenges associated with prediction of the phenotypic consequences of amino acid substitutions, the value of assaying mutant isoform function in vivo, and how recently developed tools and resources afford the opportunity to expand our understanding even of highly conserved regulatory modules such as insulin signaling. This approach may prove generally useful for modeling phenotypic consequences of candidate human pathogenic mutations in conserved signaling and developmental pathways.

  1. Developmental abnormality induced by strong static magnetic field in Caenorhabditis elegans.

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    Wang, Lei; Du, Hua; Guo, Xiaoying; Wang, Xinan; Wang, Meimei; Wang, Yichen; Wang, Min; Chen, Shaopeng; Wu, Lijun; Xu, An

    2015-04-01

    Understanding the effects of strong static magnetic fields (SMFs) on living organisms is significant in health risk assessment, but underlying mechanisms are largely unknown. In the present study, we determined developmental abnormalities induced by 8.5Tesla (T) SMFs in a well-established in vivo model organism, Caenorhabditis elegans (C. elegans). Exposure of C. elegans eggs to 8.5 T SMF resulted in a time-dependent lifespan decrease, whereas only slight changes were observed upon exposure to 5 T SMF. Although SMF exposure did not alter brood size, development rate and stages were significantly modified by 8.5 T SMF. Germ cell apoptosis dramatically increased upon exposure to 8.5 T SMF in adult worms, as confirmed by ced-3 and ced-4 mutants, and could be prevented by concurrent treatment with a free radical scavenger, dimethyl sulfoxide. Compared to wild-type worms, shorter lifespan and greater numbers of apoptotic cells were observed in abnormal methyl viologen sensitivity-1 (mev-1(kn1)) nematodes with increased sensitivity to oxidative damage. Furthermore, exposure to 8.5 T SMF increased expression of superoxide dismutase-3 (sod-3), which is thought to protect against oxidative stress. However, 8.5 T SMF had minimal effects on lifespans of daf-2 and daf-16 mutants, which have compromised insulin/IGF-1 (insulin-like growth factors-1) mediated signaling pathways; this finding was consistent with the expression of these genes in wild-type worms. Our results indicate that developmental toxicity induced by strong SMF in C. elegans is mediated by oxidative stress and may be regulated by the insulin-like receptor pathway.

  2. A systems toxicology approach on the mechanism of uptake and toxicity of MWCNT in Caenorhabditis elegans.

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    Eom, Hyun-Jeong; Roca, Carlos P; Roh, Ji-Yeon; Chatterjee, Nivedita; Jeong, Jae-Seong; Shim, Ilseob; Kim, Hyun-Mi; Kim, Phil-Je; Choi, Kyunghee; Giralt, Francesc; Choi, Jinhee

    2015-09-01

    The increased volumes of carbon nanotubes (CNTs) being utilized in industrial and biomedical processes carries with it an increased risk of unintentional release into the environment, requiring a thorough hazard and risk assessment. In this study, the toxicity of pristine and hydroxylated (OH-) multiwall CNTs (MWCNTs) was investigated in the nematode Caenorhabditis elegans using an integrated systems toxicology approach. To gain an insight into the toxic mechanism of MWCNTs, microarray and proteomics were conducted for C. elegans followed by pathway analyses. The results of pathway analyses suggested endocytosis, phagocytosis, oxidative stress and endoplasmic reticulum (ER) stress, as potential mechanisms of uptake and toxicity, which were subsequently investigated using loss-of-function mutants of genes of those pathways. The expression of phagocytosis related genes (i.e. ced-10 and rab-7) were significantly increased upon exposure to OH-MWCNT, concomitantly with the rescued toxicity by loss-of-function mutants of those genes, such as ced-10(n3246) and rab-7(ok511). An increased sensitivity of the hsp-4(gk514) mutant by OH-MWCNT, along with a decreased expression of hsp-4 at both gene and protein level suggests that MWCNTs may affect ER stress response in C. elegans. Collectively, the results implied phagocytosis to be a potential mechanism of uptake of MWCNTs, and ER and oxidative stress as potential mechanisms of toxicity. The integrated systems toxicology approach applied in this study provided a comprehensive insight into the toxic mechanism of MWCNTs in C. elegans, which may eventually be used to develop an "Adverse Outcome Pathway (AOP)", a recently introduced concept as a conceptual framework to link molecular level responses to higher level effects.

  3. Analyzing Defects in the "Caenorhabditis Elegans" Nervous System Using Organismal and Cell Biological Approaches

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    Guziewicz, Megan; Vitullo, Toni; Simmons, Bethany; Kohn, Rebecca Eustance

    2002-01-01

    The goal of this laboratory exercise is to increase student understanding of the impact of nervous system function at both the organismal and cellular levels. This inquiry-based exercise is designed for an undergraduate course examining principles of cell biology. After observing the movement of "Caenorhabditis elegans" with defects in their…

  4. Ascaroside expression in Caenorhabditis elegans is strongly dependent on diet and developmental stage

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    A group of small signaling molecules called ascarosides, associated with dauer formation, male attraction and social behavior in the nematode Caenorhabditis elegans, are shown to be regulated by developmental stage and environmental factors. The concentration of dauer-inducing ascaroside, ascr#2, i...

  5. Distinct Mechanisms Underlie Quiescence during Two Caenorhabditis elegans Sleep-Like States

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    Trojanowski, Nicholas F.; Nelson, Matthew D.; Flavell, Steven W.; Fang-Yen, Christopher; Raizen, David M.

    2015-01-01

    Electrophysiological recordings have enabled identification of physiologically distinct yet behaviorally similar states of mammalian sleep. In contrast, sleep in nonmammals has generally been identified behaviorally and therefore regarded as a physiologically uniform state characterized by quiescence of feeding and locomotion, reduced responsiveness, and rapid reversibility. The nematode Caenorhabditis elegans displays sleep-like quiescent behavior under two conditions: developmentally timed ...

  6. Caenorhabditis elegans utilizes dauer pheromone biosynthesis to dispose of toxic peroxisomal fatty acids for cellular homoeostasis

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    Caenorhabditis elegans secretes a dauer pheromone or daumone composed of ascarylose and a fatty acid side chain, perception of which enables worms to gauge depletion of food or a high worm population density. As a result, worms enter the dauer state, a specific developmental stage capable of surviv...

  7. Studying Human Disease Genes in "Caenorhabditis Elegans": A Molecular Genetics Laboratory Project

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    Cox-Paulson, Elisabeth A.; Grana, Theresa M.; Harris, Michelle A.; Batzli, Janet M.

    2012-01-01

    Scientists routinely integrate information from various channels to explore topics under study. We designed a 4-wk undergraduate laboratory module that used a multifaceted approach to study a question in molecular genetics. Specifically, students investigated whether "Caenorhabditis elegans" can be a useful model system for studying genes…

  8. Comparative functional analysis of the Caenorhabditis elegans and Drosophila melanogaster proteomes.

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    Sabine P Schrimpf

    2009-03-01

    Full Text Available The nematode Caenorhabditis elegans is a popular model system in genetics, not least because a majority of human disease genes are conserved in C. elegans. To generate a comprehensive inventory of its expressed proteome, we performed extensive shotgun proteomics and identified more than half of all predicted C. elegans proteins. This allowed us to confirm and extend genome annotations, characterize the role of operons in C. elegans, and semiquantitatively infer abundance levels for thousands of proteins. Furthermore, for the first time to our knowledge, we were able to compare two animal proteomes (C. elegans and Drosophila melanogaster. We found that the abundances of orthologous proteins in metazoans correlate remarkably well, better than protein abundance versus transcript abundance within each organism or transcript abundances across organisms; this suggests that changes in transcript abundance may have been partially offset during evolution by opposing changes in protein abundance.

  9. Caenorhabditis elegans as a Model System for Studying Drug Induced Mitochondrial Toxicity.

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    Richard de Boer

    Full Text Available Today HIV-1 infection is recognized as a chronic disease with obligatory lifelong treatment to keep viral titers below detectable levels. The continuous intake of antiretroviral drugs however, leads to severe and even life-threatening side effects, supposedly by the deleterious impact of nucleoside-analogue type compounds on the functioning of the mitochondrial DNA polymerase. For detailed investigation of the yet partially understood underlying mechanisms, the availability of a versatile model system is crucial. We therefore set out to develop the use of Caenorhabditis elegans to study drug induced mitochondrial toxicity. Using a combination of molecular-biological and functional assays, combined with a quantitative analysis of mitochondrial network morphology, we conclude that anti-retroviral drugs with similar working mechanisms can be classified into distinct groups based on their effects on mitochondrial morphology and biochemistry. Additionally we show that mitochondrial toxicity of antiretroviral drugs cannot be exclusively attributed to interference with the mitochondrial DNA polymerase.

  10. Asymmetric enrichment of PIE-1 in the Caenorhabditis elegans zygote mediated by binary counterdiffusion.

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    Daniels, Brian R; Perkins, Edward M; Dobrowsky, Terrence M; Sun, Sean X; Wirtz, Denis

    2009-02-23

    To generate cellular diversity in developing organisms while simultaneously maintaining the developmental potential of the germline, germ cells must be able to preferentially endow germline daughter cells with a cytoplasmic portion containing specialized cell fate determinants not inherited by somatic cells. In Caenorhabditis elegans, germline inheritance of the protein PIE-1 is accomplished by first asymmetrically localizing the protein to the germplasm before cleavage and subsequently degrading residual levels of the protein in the somatic cytoplasm after cleavage. Despite its critical involvement in cell fate determination, the enrichment of germline determinants remains poorly understood. Here, combining live-cell fluorescence methods and kinetic modeling, we demonstrate that the enrichment process does not involve protein immobilization, intracellular compartmentalization, or localized protein degradation. Instead, our results support a heterogeneous reaction/diffusion model for PIE-1 enrichment in which the diffusion coefficient of PIE-1 is reversibly reduced in the posterior, resulting in a stable protein gradient across the zygote at steady state.

  11. Identification of potential anti-infectives against Staphylococcus aureus using a Caenorhabditis elegans infection model

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    Kong, Cin; Rahman, Noorsaadah Abd; Nathan, Sheila

    2014-09-01

    The alarming increase of antibiotic-resistant Staphylococcus aureus and a delay in antibiotics development point to the need for novel therapeutic approaches to combat infection. To discover novel anti-infective agents, we screened a number of synthetic compounds comprising mainly of chalcone derivatives to explore their potential in promoting the survival of the nematode Caenorhabditis elegans upon infection by S. aureus. Screening of seven chalcone derivatives using both agar- and liquid-based assays revealed three positive hits that significantly prolonged the survival of S. aureus-infected nematodes. All the hits did not interfere with bacterial growth in vitro, proposing that the three compounds identified most probably act through mechanisms distinct from conventional antibiotics that target bacterial replication.

  12. WormClassroom.org: An Inquiry-rich Educational Web Portal for Research Resources of Caenorhabditis elegans

    Science.gov (United States)

    Lu, Fong-Mei; Stewart, James; White, John G.

    2007-01-01

    The utilization of biology research resources, coupled with a “learning by inquiry” approach, has great potential to aid students in gaining an understanding of fundamental biological principles. To help realize this potential, we have developed a Web portal for undergraduate biology education, WormClassroom.org, based on current research resources of a model research organism, Caenorhabditis elegans. This portal is intended to serve as a resource gateway for students to learn biological concepts using C. elegans research material. The driving forces behind the WormClassroom website were the strengths of C. elegans as a teaching organism, getting researchers and educators to work together to develop instructional materials, and the 3 P's (problem posing, problem solving, and peer persuasion) approach for inquiry learning. Iterative assessment is an important aspect of the WormClassroom site development because it not only ensures that content is up-to-date and accurate, but also verifies that it does, in fact, aid student learning. A primary assessment was performed to refine the WormClassroom website utilizing undergraduate biology students and nonstudent experts such as C. elegans researchers; results and comments were used for site improvement. We are actively encouraging continued resource contributions from the C. elegans research and education community for the further development of WormClassroom. PMID:17548872

  13. Effects of gravity on meiosis, fertilization and early embryogenesis in Caenorhabditis elegans

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    Sasagawa, Y.; Saito, Y.; Shimizu, M.; Ishioka, N.; Yamashita, M.; Takahashi, H.; Higashitani, A.

    The embryonic development of the nematode Caenorhabditis elegans was examined under different gravitational conditions. The first cleavage plane in the 1-cell embryo was slid to some extent by re-orientation of liquid culture vessel, but the pattern and timing of cleavages were not affected. Under 100G of hypergravity condition with swing-centrifuge, the number of eggs laid from an adult hermaphrodite decreased and their hatching rate was drastically reduced. On the other hand, the embryonic development after fertilization normally occurred and grew to adulthood at more than 100G of hypergravity. When the adult hermaphrodites cultured under 100G of hypergravity transferred to a ground condition (1G), the newly fertilized embryos normally developed and their hatching rate was fully recovered. These results indicated that the reproductive process except spermatogenesis, oogenesis and embryogenesis after fertilization is impaired under 100G of hypergravity condition, and the effect is transient. Namely, the fertilization process including meiotic divisions I and II is sensitive to hypergravity in the nematode C. elegans.

  14. Full toxicity assessment of Genkwa Flos and the underlying mechanism in nematode Caenorhabditis elegans.

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    Yan Qiao

    Full Text Available Genkwa Flos (GF, the dried flower bud from Daphne genkwa Sieb. et Zucc. (Thymelaeaceae, is a well-known and widely used traditional Chinese medicine. However, we know little about the in vivo mechanism of GF toxicity. Nematode Caenorhabditis elegans has been considered as a useful toxicity assay system by offering a system best suited for asking the in vivo questions. In the present study, we employed the prolonged exposure assay system of C. elegans to perform the full in vivo toxicity assessment of raw-processed GF. Our data show that GF exposure could induce the toxicity on lifespan, development, reproduction, and locomotion behavior. GF exposure not only decreased body length but also induced the formation of abnormal vulva. The decrease in brood size in GF exposed nematodes appeared mainly at day-1 during the development of adult nematodes. The decrease of locomotion behavior in GF exposed nematodes might be due to the damage on development of D-type GABAergic motor neurons. Moreover, we observed the induction of intestinal reactive oxygen species (ROS production and alteration of expression patterns of genes required for development of apical domain, microvilli, and apical junction of intestine in GF exposed nematodes, implying the possible dysfunction of the primary targeted organ. In addition, GF exposure induced increase in defecation cycle length and deficits in development of AVL and DVB neurons controlling the defecation behavior. Therefore, our study implies the usefulness of C. elegans assay system for toxicity assessment from a certain Chinese medicine or plant extract. The observed toxicity of GF might be the combinational effects of oxidative stress, dysfunction of intestine, and altered defecation behavior in nematodes.

  15. AceTree: a tool for visual analysis of Caenorhabditis elegans embryogenesis

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    Araya Carlos L

    2006-06-01

    Full Text Available Abstract Background The invariant lineage of the nematode Caenorhabditis elegans has potential as a powerful tool for the description of mutant phenotypes and gene expression patterns. We previously described procedures for the imaging and automatic extraction of the cell lineage from C. elegans embryos. That method uses time-lapse confocal imaging of a strain expressing histone-GFP fusions and a software package, StarryNite, processes the thousands of images and produces output files that describe the location and lineage relationship of each nucleus at each time point. Results We have developed a companion software package, AceTree, which links the images and the annotations using tree representations of the lineage. This facilitates curation and editing of the lineage. AceTree also contains powerful visualization and interpretive tools, such as space filling models and tree-based expression patterning, that can be used to extract biological significance from the data. Conclusion By pairing a fast lineaging program written in C with a user interface program written in Java we have produced a powerful software suite for exploring embryonic development.

  16. Royalactin extends lifespan of Caenorhabditis elegans through epidermal growth factor signaling.

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    Detienne, Giel; De Haes, Wouter; Ernst, Ulrich R; Schoofs, Liliane; Temmerman, Liesbet

    2014-12-01

    Royalactin is a glycoprotein essential for the development of long-lived queen honeybees. Only larvae fed with royal jelly, containing royalactin, develop into queens. Royalactin plays a central role in this process by switching on the epidermal growth factor (EGF) receptor signaling pathway which ultimately leads to epigenetic changes and a long-lived queen phenotype. Recently it was shown that royalactin by itself also extends lifespan in Drosophila melanogaster. Yet, the mechanism by which royalactin promotes longevity remains largely unknown. We set out to characterize the effects of royalactin on Caenorhabditis elegans lifespan, and clarify the possible involvement of EGF signaling in this process. We demonstrate that royalactin extends lifespan of this nematode and that both EGF (LIN-3) and its receptor (LET-23) are essential to this process. To our knowledge, this is the first report of royalactin-mediated lifespan extension in a non-insect species. Additionally, we show that royalactin enhances locomotion in adult nematodes, implying that royalactin also influences healthspan. Our results suggest that royalactin is an important lifespan-extending factor in royal jelly and acts by promoting EGF signaling in C. elegans. Further work will now be needed to clarify which (secondary) signaling pathways are activated by royalactin, and how this ultimately translates into an extended health- and lifespan.

  17. Solution structure of CEH-37 homeodomain of the nematode Caenorhabditis elegans

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    Moon, Sunjin [Structural Biochemistry and Molecular Biophysics Lab, Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Yong Woo; Kim, Woo Taek [Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Weontae, E-mail: wlee@spin.yonsei.ac.kr [Structural Biochemistry and Molecular Biophysics Lab, Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2014-01-10

    Highlights: •We have determined solution structures of CEH-37 homedomain. •CEH-37 HD has a compact α-helical structure with HTH DNA binding motif. •Solution structure of CEH-37 HD shares its molecular topology with that of the homeodomain proteins. •Residues in the N-terminal region and HTH motif are important in binding to Caenorhabditis elegans telomeric DNA. •CEH-37 could play an important role in telomere function via DNA binding. -- Abstract: The nematode Caenorhabditis elegans protein CEH-37 belongs to the paired OTD/OTX family of homeobox-containing homeodomain proteins. CEH-37 shares sequence similarity with homeodomain proteins, although it specifically binds to double-stranded C. elegans telomeric DNA, which is unusual to homeodomain proteins. Here, we report the solution structure of CEH-37 homeodomain and molecular interaction with double-stranded C. elegans telomeric DNA using nuclear magnetic resonance (NMR) spectroscopy. NMR structure shows that CEH-37 homeodomain is composed of a flexible N-terminal region and three α-helices with a helix-turn-helix (HTH) DNA binding motif. Data from size-exclusion chromatography and fluorescence spectroscopy reveal that CEH-37 homeodomain interacts strongly with double-stranded C. elegans telomeric DNA. NMR titration experiments identified residues responsible for specific binding to nematode double-stranded telomeric DNA. These results suggest that C. elegans homeodomain protein, CEH-37 could play an important role in telomere function via DNA binding.

  18. Nematodes join the family of chondroitin sulfate-synthesizing organisms: Identification of an active chondroitin sulfotransferase in Caenorhabditis elegans

    Science.gov (United States)

    Dierker, Tabea; Shao, Chun; Haitina, Tatjana; Zaia, Joseph; Hinas, Andrea; Kjellén, Lena

    2016-01-01

    Proteoglycans are proteins that carry sulfated glycosaminoglycans (GAGs). They help form and maintain morphogen gradients, guiding cell migration and differentiation during animal development. While no sulfated GAGs have been found in marine sponges, chondroitin sulfate (CS) and heparan sulfate (HS) have been identified in Cnidarians, Lophotrocozoans and Ecdysozoans. The general view that nematodes such as Caenorhabditis elegans, which belong to Ecdysozoa, produce HS but only chondroitin without sulfation has therefore been puzzling. We have analyzed GAGs in C. elegans using reversed-phase ion-pairing HPLC, mass spectrometry and immunohistochemistry. Our analyses included wild type C. elegans but also a mutant lacking two HS sulfotransferases (hst-6 hst-2), as we suspected that the altered HS structure could boost CS sulfation. We could indeed detect sulfated CS in both wild type and mutant nematodes. While 4-O-sulfation of galactosamine dominated, we also detected 6-O-sulfated galactosamine residues. Finally, we identified the product of the gene C41C4.1 as a C. elegans CS-sulfotransferase and renamed it chst-1 (CarboHydrate SulfoTransferase) based on loss of CS-4-O-sulfation in a C41C4.1 mutant and in vitro sulfotransferase activity of recombinant C41C4.1 protein. We conclude that C. elegans indeed manufactures CS, making this widely used nematode an interesting model for developmental studies involving CS. PMID:27703236

  19. Winter Aconite (Eranthis hyemalis Lectin as a cytotoxic effector in the lifecycle of Caenorhabditis elegans

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    Marie-Therese McConnell

    2015-08-01

    Full Text Available The lectin found in the tubers of the Winter Aconite (Eranthis hyemalis plant is an N-acetyl-D-galactosamine specific Type II Ribosome Inactivating Protein (RIP; Type II RIPs have shown anti-cancer properties, and hence have potential as therapeutic agents. Here we present a modified protocol for the extraction and purification of the E. hyemalis lectin (EHL using affinity chromatography. De novo amino acid sequencing of EHL confirms its classification as a Type II Ribosome Inactivating Protein. The biocidal properties of EHL have been investigated against the nematode Caenorhabditis elegans. Arrested first stage larvae treated with EHL have shown some direct mortality, with surviving larvae subsequently showing a range of phenotypes including food avoidance, reduced fecundity, developmental delay and constitutive dauer larvae formation. Both inappropriate dauer larvae development and failure to locate to bacterial food source are consistent with the disruption of chemosensory function and the ablation of amphid neurons. Further investigation indicates that mutations that disrupt normal amphid formation can block the EHL-induced dauer larvae formation. In combination, these phenotypes indicate that EHL is cytotoxic and suggest a cell specific activity against the amphid neurons of C. elegans.

  20. DNA methylation modulates Salmonella enterica serovar Typhimurium virulence in Caenorhabditis elegans.

    Science.gov (United States)

    Oza, Javin P; Yeh, Jimmy B; Reich, Norbert O

    2005-04-01

    Salmonella enterica serovar Typhimurium was previously shown to be virulent in Caenorhabditis elegans. Here we demonstrate that DNA adenine methyltransferase (DAM) modulates Salmonella virulence in the nematode, as it does in mice. After 5 days of continual exposure to bacteria, twice as many worms died when exposed to the wild-type than the dam-mutant strain of Salmonella. Similar trends in virulence were observed when worms were exposed to Salmonella strains for 5 h and transferred to the avirulent Escherichia coli OP50. While a 10-fold attenuation was observed in the absence of DAM, the dam-strain was still able to infect and persist in the host worm. Our results further support the use of C. elegans as an accessible and readily studied animal model of bacterial pathogenesis. However, our results suggest that crucial host responses differ between the murine and nematode models. Additionally, we carried out preliminary liquid culture based experiments with the long term goal of developing high throughput animal based screens of DAM inhibitors.

  1. Characterization of the crawling activity of Caenorhabditis elegans using a Hidden Markov model.

    Science.gov (United States)

    Lee, Sang-Hee; Kang, Seung-Ho

    2015-12-01

    The locomotion behavior of Caenorhabditis elegans has been studied extensively to understand the respective roles of neural control and biomechanics as well as the interaction between them. Constructing a mathematical model is helpful to understand the locomotion behavior in various surrounding conditions that are difficult to realize in experiments. In this study, we built three hidden Markov models (HMMs) for the crawling behavior of C. elegans in a controlled environment with no chemical treatment and in a formaldehyde-treated environment (0.1 and 0.5 ppm). The organism's crawling activity was recorded using a digital camcorder for 20 min at a rate of 24 frames per second. All shape patterns were quantified by branch length similarity (BLS) entropy and classified into four groups using the self-organizing map (SOM). Comparison of the simulated behavior generated by HMMs and the actual crawling behavior demonstrated that the HMM coupled with the SOM was successful in characterizing the crawling behavior. In addition, we briefly discussed the possibility of using the HMM together with BLS entropy to develop bio-monitoring systems to determine water quality.

  2. Susceptibility of Caenorhabditis elegans to Burkholderia infection depends on prior diet and secreted bacterial attractants.

    Directory of Open Access Journals (Sweden)

    Vaughn S Cooper

    Full Text Available The nematode Caenorhabditis elegans may be killed by certain pathogenic bacteria and thus is a model organism for studying interactions between bacteria and animal hosts. However, growing nematodes on prey bacteria may influence their susceptibility to potential pathogens. A method of axenic nematode culture was developed to isolate and quantify interactions between C. elegans and potentially pathogenic strains of the Burkholderia cepacia complex. Studying these dynamics in liquid solution rather than on agar surfaces minimized nematode avoidance behavior and resolved more differences among isolates. Most isolates of B. cenocepacia, B. ambifaria and B. cepacia caused 60-80% mortality of nematodes after 7 days, whereas isolates of B. multivorans caused less mortality (<25% and supported nematode reproduction. However, some B. cenocepacia isolates recovered from chronic infections were much less virulent (5-28% mortality. As predicted, prior diet altered the outcome of interactions between nematodes and bacteria. When given the choice between Burkholderia and E. coli as prey on agar, axenically raised nematodes initially preferred most lethal Burkholderia isolates to E. coli as a food source, but this was not the case for nematodes fed E. coli, which avoided toxic Burkholderia. This food preference was associated with the cell-free supernatant and thus secreted compounds likely mediated bacterial-nematode interactions. This model, which isolates interactions between bacteria and nematodes from the effects of prior feeding, demonstrates that bacteria can influence nematode behavior and their susceptibility to pathogens.

  3. Worming forward: amyotrophic lateral sclerosis toxicity mechanisms and genetic interactions in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Martine eTherrien

    2014-04-01

    Full Text Available Neurodegenerative diseases share pathogenic mechanisms at the cellular level including protein misfolding, excitotoxicity and altered RNA homeostasis among others. Recent advances have shown that the genetic causes underlying these pathologies overlap, hinting at the existence of a genetic network for neurodegeneration. This is perhaps best illustrated by the recent discoveries of causative mutations for amyotrophic lateral sclerosis (ALS and frontotemporal degeneration (FTD. Once thought to be distinct entities, it is now recognized that these diseases exist along a genetic spectrum. With this wealth of discoveries comes the need to develop new genetic models of ALS and FTD to investigate not only pathogenic mechanisms linked to causative mutations, but to uncover potential genetic interactions that may point to new therapeutic targets. Given the conservation of many disease genes across evolution, Caenorhabditis elegans is an ideal system to investigate genetic interactions amongst these genes. Here we review the use of C. elegans to model ALS and investigate a putative genetic network for ALS/FTD that may extend to other neurological disorders.

  4. Ultraviolet-A triggers photoaging in model nematode Caenorhabditis elegans in a DAF-16 dependent pathway.

    Science.gov (United States)

    Prasanth, Mani Iyer; Santoshram, Gunasekaran Santhi; Bhaskar, James Prabhanand; Balamurugan, Krishnaswamy

    2016-02-01

    Ultraviolet radiations (UV) are the primary causative agent for skin aging (photoaging) and cancer, especially UV-A. The mode of action and the molecular mechanism behind the damages caused by UV-A is not well studied, in vivo. The current study was employed to investigate the impact of UV-A exposure using the model organism, Caenorhabditis elegans. Analysis of lifespan, healthspan, and other cognitive behaviors were done which was supported by the molecular mechanism. UV-A exposure on collagen damages the synthesis and functioning which has been monitored kinetically using engineered strain, col-19:: GFP. The study results suggested that UV-A accelerated the aging process in an insulin-like signaling pathway dependent manner. Mutant (daf-2)-based analysis concrete the observations of the current study. The UV-A exposure affected the usual behavior of the worms like pharyngeal movements and brood size. Quantitative PCR profile of the candidate genes during UV-A exposure suggested that continuous exposure has damaged the neural network of the worms, but the mitochondrial signaling and dietary restriction pathway remain unaffected. Western blot analysis of HSF-1 evidenced the alteration in protein homeostasis in UV-A exposed worms. Outcome of the current study supports our view that C. elegans can be used as a model to study photoaging, and the mode of action of UV-A-mediated damages can be elucidated which will pave the way for drug developments against photoaging.

  5. Differential assembly of alpha- and gamma-filagenins into thick filaments in Caenorhabditis elegans

    Science.gov (United States)

    Liu, F.; Ortiz, I.; Hutagalung, A.; Bauer, C. C.; Cook, R. G.; Epstein, H. F.

    2000-01-01

    Muscle thick filaments are highly organized supramolecular assemblies of myosin and associated proteins with lengths, diameters and flexural rigidities characteristic of their source. The cores of body wall muscle thick filaments of the nematode Caenorhabditis elegans are tubular structures of paramyosin sub-filaments coupled by filagenins and have been proposed to serve as templates for the assembly of native thick filaments. We have characterized alpha- and gamma-filagenins, two novel proteins of the cores with calculated molecular masses of 30,043 and 19,601 and isoelectric points of 10.52 and 11.49, respectively. Western blot and immunoelectron microscopy using affinity-purified antibodies confirmed that the two proteins are core components. Immunoelectron microscopy of the cores revealed that they assemble with different periodicities. Immunofluorescence microscopy showed that alpha-filagenin is localized in the medial regions of the A-bands of body wall muscle cells whereas gamma-filagenin is localized in the flanking regions, and that alpha-filagenin is expressed in 1.5-twofold embryos while gamma-filagenin becomes detectable only in late vermiform embryos. The expression of both proteins continues throughout later stages of development. C. elegans body wall muscle thick filaments of these developmental stages have distinct lengths. Our results suggest that the differential assembly of alpha- and gamma-filagenins into thick filaments of distinct lengths may be developmentally regulated.

  6. Characterization of Caenorhabditis elegans behavior in response to chemical stress by using hidden Markov model

    Science.gov (United States)

    Choi, Yeontaek; Sim, Seungwoo; Lee, Sang-Hee

    2014-06-01

    The locomotion behavior of Caenorhabditis elegans has been extensively studied to understand the relationship between the changes in the organism's neural activity and the biomechanics. However, so far, we have not yet achieved the understanding. This is because the worm complicatedly responds to the environmental factors, especially chemical stress. Constructing a mathematical model is helpful for the understanding the locomotion behavior in various surrounding conditions. In the present study, we built three hidden Markov models for the crawling behavior of C. elegans in a controlled environment with no chemical treatment and in a polluted environment by formaldehyde, toluene, and benzene (0.1 ppm and 0.5 ppm for each case). The organism's crawling activity was recorded using a digital camcorder for 20 min at a rate of 24 frames per second. All shape patterns were quantified by branch length similarity entropy and classified into five groups by using the self-organizing map. To evaluate and establish the hidden Markov models, we compared correlation coefficients between the simulated behavior (i.e. temporal pattern sequence) generated by the models and the actual crawling behavior. The comparison showed that the hidden Markov models are successful to characterize the crawling behavior. In addition, we briefly discussed the possibility of using the models together with the entropy to develop bio-monitoring systems for determining water quality.

  7. Establishment of quality assurance procedures for aquatic toxicity testing with the nematode Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, M.N.; Marse, T.J.; Williams, P.L. [Univ. of Georgia, Athens, GA (United States). Environmental Health Science Program

    1998-12-31

    In this study initial data were generated to develop laboratory control charts for aquatic toxicity testing using the nematode Caenorhabditis elegans. Tests were performed using two reference toxicants: CdCl{sub 2} and CuCl{sub 2}. All tests were performed for 24 h without a food source and of 48 h with a food source in a commonly used nematode aquatic medium. Each test was replicated 6 times with each replicate having 6 wells per concentration with 10 {+-} 1 worms per well. Probit analysis was used to estimate LC{sub 50} values for each test. The data were used to construct a mean ({bar x}) laboratory control chart for each reference toxicant. The coefficient of variation (CV) for three of the four reference toxicant tests was less than 20%, which demonstrates an excellent degree of reproducibility. These CV values are well within suggested standards for determination of organism sensitivity and overall test system credibility. A standardized procedure for performing 24 h and 48 h aquatic toxicity studies with C. elegans is proposed.

  8. Protein kinase VRK-1 regulates cell invasion and EGL-17/FGF signaling in Caenorhabditis elegans.

    Science.gov (United States)

    Klerkx, Elke P F; Alarcón, Pilar; Waters, Katherine; Reinke, Valerie; Sternberg, Paul W; Askjaer, Peter

    2009-11-01

    The vaccinia-related kinases (VRKs) are highly conserved throughout the animal kingdom and phosphorylate several chromatin proteins and transcription factors. In early Caenorhabditis elegans embryos, VRK-1 is required for proper nuclear envelope formation. In this work, we present the first investigation of the developmental role of VRKs by means of a novel C. elegans vrk-1 mutant allele. We found that VRK-1 is essential in hermaphrodites for formation of the vulva, uterus, and utse and for development and maintenance of the somatic gonad and thus the germ line. VRK-1 regulates anchor cell polarity and the timing of anchor cell invasion through the basement membranes separating vulval and somatic gonadal cells during the L3 larval stage. VRK-1 is also required for proper specification and proliferation of uterine cells and sex myoblasts. Expression of the fibroblast growth factor-like protein EGL-17 and its receptor EGL-15 is reduced in vrk-1 mutants, suggesting that VRK-1 might act at least partially through activation of FGF signaling. Expression of a translational VRK-1Colon, two colonsGFP fusion protein in the ventral nerve cord and vulva precursor cells restores vulva and uterus formation, suggesting both cell autonomous and non-autonomous roles of VRK-1.

  9. A novel high-throughput nematicidal assay using embryo cells and larvae of Caenorhabditis elegans.

    Science.gov (United States)

    Lai, Yiling; Xiang, Meichun; Liu, Shuchun; Li, Erwei; Che, Yongsheng; Liu, Xingzhong

    2014-04-01

    Human health safety and environmental concerns have resulted in the widespread deregistration of several agronomic important nematicides. New and safer nematicides are urgently needed. However, a high-throughput bioassay for screening potential nematicides has not been established. We developed a two-step high-throughput nematicidal screening method to combine a cell-based MTS colorimetric assay with Caenorhabditis elegans embryo cells for preliminary cytotoxicity screening (step 1) followed by in vitro larval assay for nematicidal activity (step 2). Based on three conventional nematicides' test, high correlations were obtained between cell viability and larval viability and "r" values were 0.78 for Avermectin, 0.95 for Fosthiazate, and 0.65 for Formaldehyde solution. Further assays with 60 fungal secondary metabolites (extracts, fractions and pure compounds) also demonstrated the high correlation between cell viability and larval viability (r=0.60) and between the C. elegans cell viability and the juvenile viability of soybean cyst nematode Heterodera glycines (r=0.48) and pine wood nematode Bursaphelenchus xylophilus (r=0.56). Six metabolites with high cytotoxicity have performed high larval mortality with a LC50 range of 6.8-500μg/ml. These results indicate that the proposed two-step screening assay represents an efficient and labor-saving method for screening natural nematicidal products.

  10. Chromosome-biased binding and gene regulation by the Caenorhabditis elegans DRM complex.

    Directory of Open Access Journals (Sweden)

    Tomoko M Tabuchi

    2011-05-01

    Full Text Available DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we describe new aspects of DRM binding and function revealed through genome-wide analyses of the Caenorhabditis elegans DRM subunit LIN-54. We show that LIN-54 DNA-binding activity recruits DRM to promoters enriched for adjacent putative E2F/DP and LIN-54 binding sites, suggesting that these two DNA-binding moieties together direct DRM to its target genes. Chromatin immunoprecipitation and gene expression profiling reveals conserved roles for DRM in regulating genes involved in cell division, development, and reproduction. We find that LIN-54 promotes expression of reproduction genes in the germline, but prevents ectopic activation of germline-specific genes in embryonic soma. Strikingly, C. elegans DRM does not act uniformly throughout the genome: the DRM recruitment motif, DRM binding, and DRM-regulated embryonic genes are all under-represented on the X chromosome. However, germline genes down-regulated in lin-54 mutants are over-represented on the X chromosome. We discuss models for how loss of autosome-bound DRM may enhance germline X chromosome silencing. We propose that autosome-enriched binding of DRM arose in C. elegans as a consequence of germline X chromosome silencing and the evolutionary redistribution of germline-expressed and essential target genes to autosomes. Sex chromosome gene regulation may thus have profound evolutionary effects on genome organization and transcriptional regulatory networks.

  11. Intestinal autophagy activity is essential for host defense against Salmonella typhimurium infection in Caenorhabditis elegans.

    Science.gov (United States)

    Curt, Alexander; Zhang, Jiuli; Minnerly, Justin; Jia, Kailiang

    2014-08-01

    Salmonella typhimurium infects both intestinal epithelial cells and macrophages. Autophagy is a lysosomal degradation pathway that is present in all eukaryotes. Autophagy has been reported to limit the Salmonella replication in Caenorhabditis elegans and in mammals. However, it is unknown whether intestinal autophagy activity plays a role in host defense against Salmonella infection in C. elegans. In this study, we inhibited the autophagy gene bec-1 in different C. elegans tissues and examined the survival of these animals following Salmonella infection. Here we show that inhibition of the bec-1 gene in the intestine but not in other tissues confers susceptibility to Salmonella infection, which is consistent with recent studies in mice showing that autophagy is involved in clearance of Salmonella in the intestinal epithelial cells. Therefore, the intestinal autophagy activity is essential for host defense against Salmonella infection from C. elegans to mice, perhaps also in humans.

  12. A co-CRISPR strategy for efficient genome editing in Caenorhabditis elegans.

    Science.gov (United States)

    Kim, Heesun; Ishidate, Takao; Ghanta, Krishna S; Seth, Meetu; Conte, Darryl; Shirayama, Masaki; Mello, Craig C

    2014-08-01

    Genome editing based on CRISPR (clustered regularly interspaced short palindromic repeats)-associated nuclease (Cas9) has been successfully applied in dozens of diverse plant and animal species, including the nematode Caenorhabditis elegans. The rapid life cycle and easy access to the ovary by micro-injection make C. elegans an ideal organism both for applying CRISPR-Cas9 genome editing technology and for optimizing genome-editing protocols. Here we report efficient and straightforward CRISPR-Cas9 genome-editing methods for C. elegans, including a Co-CRISPR strategy that facilitates detection of genome-editing events. We describe methods for detecting homologous recombination (HR) events, including direct screening methods as well as new selection/counterselection strategies. Our findings reveal a surprisingly high frequency of HR-mediated gene conversion, making it possible to rapidly and precisely edit the C. elegans genome both with and without the use of co-inserted marker genes.

  13. Lipid signalling couples translational surveillance to systemic detoxification in Caenorhabditis elegans.

    Science.gov (United States)

    Govindan, J Amaranath; Jayamani, Elamparithi; Zhang, Xinrui; Breen, Peter; Larkins-Ford, Jonah; Mylonakis, Eleftherios; Ruvkun, Gary

    2015-10-01

    Translation in eukaryotes is followed to detect toxins and virulence factors and coupled to the induction of defence pathways. Caenorhabditis elegans germline-specific mutations in translation components are detected by this system to induce detoxification and immune responses in distinct somatic cells. An RNA interference screen revealed gene inactivations that act at multiple steps in lipid biosynthetic and kinase pathways upstream of MAP kinase to mediate the systemic communication of translation defects to induce detoxification genes. Mammalian bile acids can rescue the defect in detoxification gene induction caused by C. elegans lipid biosynthetic gene inactivations. Extracts prepared from C. elegans with translation deficits but not from the wild type can also rescue detoxification gene induction in lipid-biosynthesis-defective strains. These eukaryotic antibacterial countermeasures are not ignored by bacteria: particular bacterial species suppress normal C. elegans detoxification responses to mutations in translation factors.

  14. Thermal stress resistance and aging effects of Panax notoginseng polysaccharides on Caenorhabditis elegans.

    Science.gov (United States)

    Feng, Shiling; Cheng, Haoran; Xu, Zhou; Shen, Shian; Yuan, Ming; Liu, Jing; Ding, Chunbang

    2015-11-01

    Panax notoginseng attract public attention due to their potential biomedical properties and corresponding health benefits. The present study investigated the anti-aging and thermal stress resistance effects of polysaccharides from P. notoginseng on Caenorhabditis elegans. Results showed polysaccharides had little scavenging ability of reactive oxygen species (ROS) in vitro, but significantly extended lifespan of C. elegans, especially the main root polysaccharide (MRP) which prolongs the mean lifespan of wild type worms by 21%. Further study demonstrated that the heat stress resistance effect of polysaccharides on C. elegans might be attributed to the elevation of antioxidant enzyme activities (both superoxide dismutase (SOD) and catalase (CAT)) and the reduction lipid peroxidation of malondialdehyde (MDA) level. Taken together, the results provided a scientific basis for the further exploitation of the mechanism of longer lifespan controlled by P. notoginseng polysaccharides on C. elegans. The P. notoginseng polysaccharides might be considered as a potential source to delay aging.

  15. Insulin signaling genes modulate nicotine-induced behavioral responses in Caenorhabditis elegans.

    Science.gov (United States)

    Wescott, Seth A; Ronan, Elizabeth A; Xu, X Z Shawn

    2016-02-01

    Insulin signaling has been suggested to modulate nicotine dependence, but the underlying genetic evidence has been lacking. Here, we used the nematode, Caenorhabditis elegans, to investigate whether genetic alterations in the insulin signaling pathway affect behavioral responses to nicotine. For this, we challenged drug-naive C. elegans with an acute dose of nicotine (100 μmol/l) while recording changes in their locomotion speed. Although nicotine treatment stimulated locomotion speed in wild-type C. elegans, the same treatment reduced locomotion speed in mutants defective in insulin signaling. This phenotype could be suppressed by mutations in daf-16, a gene encoding a FOXO transcription factor that acts downstream of insulin signaling. Our data suggest that insulin signaling genes, daf-2, age-1, pdk-1, akt-1, and akt-2, modulate behavioral responses to nicotine in C. elegans, indicating a genetic link between nicotine behavior and insulin signaling.

  16. Communication between oocytes and somatic cells regulates volatile pheromone production in Caenorhabditis elegans.

    Science.gov (United States)

    Leighton, Daniel H W; Choe, Andrea; Wu, Shannon Y; Sternberg, Paul W

    2014-12-16

    Males of the androdioecious species Caenorhabditis elegans are more likely to attempt to mate with and successfully inseminate C. elegans hermaphrodites that do not concurrently harbor sperm. Although a small number of genes have been implicated in this effect, the mechanism by which it arises remains unknown. In the context of the battle of the sexes, it is also unknown whether this effect is to the benefit of the male, the hermaphrodite, or both. We report that successful contact between mature sperm and oocyte in the C. elegans gonad at the start of fertilization causes the oocyte to release a signal that is transmitted to somatic cells in its mother, with the ultimate effect of reducing her attractiveness to males. Changes in hermaphrodite attractiveness are tied to the production of a volatile pheromone, the first such pheromone described in C. elegans.

  17. Katz model prediction of Caenorhabditis elegans mutagenesis on STS-42

    Science.gov (United States)

    Cucinotta, Francis A.; Wilson, John W.; Katz, Robert; Badhwar, Gautam D.

    1992-01-01

    Response parameters that describe the production of recessive lethal mutations in C. elegans from ionizing radiation are obtained with the Katz track structure model. The authors used models of the space radiation environment and radiation transport to predict and discuss mutation rates for C. elegans on the IML-1 experiment aboard STS-42.

  18. Engineering the Caenorhabditis elegans genome with CRISPR/Cas9.

    Science.gov (United States)

    Waaijers, Selma; Boxem, Mike

    2014-08-01

    The development in early 2013 of CRISPR/Cas9-based genome engineering promises to dramatically advance our ability to alter the genomes of model systems at will. A single, easily produced targeting RNA guides the Cas9 endonuclease to a specific DNA sequence where it creates a double strand break. Imprecise repair of the break can yield mutations, while homologous recombination with a repair template can be used to effect specific changes to the genome. The tremendous potential of this system led several groups to independently adapt it for use in Caenorhabditiselegans, where it was successfully used to generate mutations and to create tailored genome changes through homologous recombination. Here, we review the different approaches taken to adapt CRISPR/Cas9 for C. elegans, and provide practical guidelines for CRISPR/Cas9-based genome engineering.

  19. The Caenorhabditis elegans RDE-10/RDE-11 complex regulates RNAi by promoting secondary siRNA amplification

    NARCIS (Netherlands)

    Zhang, Chi; Montgomery, Taiowa A; Fischer, Sylvia E J; Garcia, Susana M D A; Riedel, Christian G; Fahlgren, Noah; Sullivan, Christopher M; Carrington, James C; Ruvkun, Gary

    2012-01-01

    BACKGROUND: In nematodes, plants, and fungi, RNAi is remarkably potent and persistent due to the amplification of initial silencing signals by RNA-dependent RNA polymerases (RdRPs). In Caenorhabditis elegans (C. elegans), the interaction between the RNA-induced silencing complex (RISC) loaded with p

  20. The evolutionary duplication and probable demise of an endodermal GATA factor in Caenorhabditis elegans.

    OpenAIRE

    Fukushige, Tetsunari; Goszczynski, Barbara; Tian, Helen; McGhee, James D

    2003-01-01

    We describe the elt-4 gene from the nematode Caenorhabditis elegans. elt-4 is predicted to encode a very small (72 residues, 8.1 kD) GATA-type zinc finger transcription factor. The elt-4 gene is located approximately 5 kb upstream of the C. elegans elt-2 gene, which also encodes a GATA-type transcription factor; the zinc finger DNA-binding domains are highly conserved (24/25 residues) between the two proteins. The elt-2 gene is expressed only in the intestine and is essential for normal intes...

  1. Identification of novel protein functions and signaling mechanisms by genetics and quantitative phosphoproteomics in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Fredens, Julius; Engholm-Keller, Kasper; Møller-Jensen, Jakob;

    2014-01-01

    knockdown by feeding the nematode on pre-labeled lysine auxotroph Escherichia coli. In this chapter, we describe in details the generation of the E. coli strain, incorporation of heavy isotope-labeled lysine in C. elegans, and the procedure for a comprehensive global phosphoproteomic experiment.......Stable isotope labeling by amino acids combined with mass spectrometry is a widely used methodology for measuring relative changes in protein and phosphorylation levels at a global level. We have applied this method to the model organism Caenorhabditis elegans in combination with RNAi-mediated gene...

  2. H3K23me2 is a new heterochromatic mark in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Vandamme, Julien; Sidoli, Simone; Mariani, Luca;

    2015-01-01

    described in this organism. We used mass spectrometry based middle-down proteomics to analyze histone H3 N-terminal tails from C. elegans embryos for the presence, the relative abundance and the potential cross-talk of co-existing PTMs. This analysis highlighted that the lysine 23 of histone H3 (H3K23......Genome-wide analyses in Caenorhabditis elegans show that post-translational modifications (PTMs) of histones are evolutionary conserved and distributed along functionally distinct genomic domains. However, a global profile of PTMs and their co-occurrence on the same histone tail has not been...

  3. Influence of Lactic Acid Bacteria on Longevity of Caenorhabditis elegans and Host Defense against Salmonella enterica Serovar Enteritidis▿

    OpenAIRE

    Ikeda, Takanori; Yasui, Chikako; Hoshino, Kaori; Arikawa, Kentaro; Nishikawa, Yoshikazu

    2007-01-01

    This study aimed to develop a convenient model to investigate the senescence of host defenses and the influence of food and nutrition. A small soil nematode, Caenorhabditis elegans, was grown for 3 days from hatching on a lawn of Escherichia coli OP50 as the normal food source, and subsequently some of the nematodes were fed lactic acid bacteria (LAB). The life spans of worms fed LAB were significantly longer than the life spans of those fed OP50. To investigate the effect of age on host defe...

  4. Advances in the Caenorhabditis elegans genome project%线虫(Caenorhabditis elegans)基因组的研究进展

    Institute of Scientific and Technical Information of China (English)

    李菁菁; 刘良式

    2000-01-01

    线虫(Caenorhabditis elegans)是重要的模式生物,其基因组序列分析工作于1998年底基本完成,已有19000多个基因被鉴定.本文概述线虫基因组研究中遗传图谱、物理图谱、序列测定和基因识别等方面的研究成果,以及线虫基因组计划将对生命科学研究产生的影响.

  5. Shedding of foodborne pathogens by Caenorhabditis elegans in compost-amended and unamended soil.

    Science.gov (United States)

    Anderson, Gary L; Kenney, Stephen J; Millner, Patricia D; Beuchat, Larry R; Williams, Phillip L

    2006-04-01

    A study was done to characterize the shedding of foodborne pathogenic bacteria by Caenorhabditis elegans, evaluate the persistence of worm populations cocultured with foodborne pathogens, and determine if C. elegans disperses ingested pathogens in soil as a result of shedding. Escherichia. coli O157:H7, Salmonella enterica serotype Poona, and Listeria monocytogenes, as well as E. coli OP50, a non-pathogenic strain, were studied. Synchronous populations of C. elegans were fed for 24 h on confluent lawns of nalidixic acid-adapted bacteria. C. elegans shed viable cells of ingested bacteria on tryptic soy agar supplemented with nalidixic acid (50 microg ml(-1)) (TSAN) throughout a 5-h post-feeding period. C. elegans persisted for up to 10 days by feeding on bacteria that had been shed and grew on TSAN. Eggs harvested from C. elegans cultured on shed foodborne pathogens had the same level of viability as those collected from C. elegans grown on shed E. coli OP50. After 6-7 days, 78%, 64%, 64%, and 76% of eggs laid by C. elegans that had fed on E. coli O157:H7, S. Poona, L. monocytogenes, and E. coli OP50, respectively, were viable. Worms fed on E. coli O157:H7 were inoculated into soil and soil amended with turkey manure compost. Populations of C. elegans persisted in compost-amended soil for at least 7 days but declined in unamended soil. E. coli O157:H7 was detected at 4 and 6 days post inoculation in compost-amended and unamended soil, and in unamended soil inoculated with E. coli OP50. Populations of E. coli O157:H7 in soil amended with turkey manure compost were significantly(alpha = 0.05) higher than those in unamended soil. Results indicate that C. elegans can act as a vector to disperse foodborne pathogens in soil, potentially resulting in increased risk of contaminating the surface of pre-harvest fruits and vegetables.

  6. Effects of Lactobacillus salivarius, Lactobacillus reuteri, and Pediococcus acidilactici on the nematode Caenorhabditis elegans include possible antitumor activity.

    Science.gov (United States)

    Fasseas, Michael K; Fasseas, Costas; Mountzouris, Konstantinos C; Syntichaki, Popi

    2013-03-01

    This study examined the effects of three lactic acid bacteria (LAB) strains on the nematode Caenorhabditis elegans. Lactobacillus salivarius, Lactobacillus reuteri, and Pediococcus acidilactici were found to inhibit the development and growth of the worm. Compared to Escherichia coli used as the control, L. reuteri and P. acidilactici reduced the lifespan of wild-type and short-lived daf-16 worms. On the contrary, L. salivarius extended the lifespan of daf-16 worms when used live, but reduced it as UV-killed bacteria. The three LAB induced the expression of genes involved in pathogen response and inhibited the growth of tumor-like germ cells, without affecting DAF16 localization or increasing corpse cells. Our results suggest the possible use of C. elegans as a model for studying the antitumor attributes of LAB. The negative effects of these LAB strains on the nematode also indicate their potential use against parasitic nematodes.

  7. Caenorhabditis elegans as a model for the screening of anthelminthic compounds: ultrastructural study of the effects of albendazole.

    Science.gov (United States)

    Sant'anna, Viviane; Vommaro, Rossiane C; de Souza, Wanderley

    2013-09-01

    This study investigated the effects of albendazole on the viability, morphology and ultrastructure of different life stages of Caenorhabditis elegans. The albendazole EC50 value after seven days of treatment was 18.43 μM. This concentration was very efficient against all the stages. Light and electron microscopy analysis showed damage to the body wall of the adults and larvae. An intense desquamation of the cuticle of larvae and of the surface of the eggs was observed, preventing their hatching and development. The main ultrastructural damage detected was the degeneration of the mitochondria in the noncontractile muscle of the body wall, which appeared as large vacuoles. This study reaffirmed the use of C. elegans as a screening system for compounds with potential anthelmintic activity and showed the effects of albendazole on the different life stages of these worms.

  8. Mutations in a guanylate cyclase GCY-35/GCY-36 modify Bardet-Biedl syndrome-associated phenotypes in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Calvin A Mok

    2011-10-01

    Full Text Available Ciliopathies are pleiotropic and genetically heterogeneous disorders caused by defective development and function of the primary cilium. Bardet-Biedl syndrome (BBS proteins localize to the base of cilia and undergo intraflagellar transport, and the loss of their functions leads to a multisystemic ciliopathy. Here we report the identification of mutations in guanylate cyclases (GCYs as modifiers of Caenorhabditis elegans bbs endophenotypes. The loss of GCY-35 or GCY-36 results in suppression of the small body size, developmental delay, and exploration defects exhibited by multiple bbs mutants. Moreover, an effector of cGMP signalling, a cGMP-dependent protein kinase, EGL-4, also modifies bbs mutant defects. We propose that a misregulation of cGMP signalling, which underlies developmental and some behavioural defects of C. elegans bbs mutants, may also contribute to some BBS features in other organisms.

  9. Caenorhabditis elegans maintains highly compartmentalized cellular distribution of metals and steep concentration gradients of manganese.

    Directory of Open Access Journals (Sweden)

    Gawain McColl

    Full Text Available Bioinorganic chemistry is critical to cellular function. Homeostasis of manganese (Mn, for example, is essential for life. A lack of methods for direct in situ visualization of Mn and other biological metals within intact multicellular eukaryotes limits our understanding of management of these metals. We provide the first quantitative subcellular visualization of endogenous Mn concentrations (spanning two orders of magnitude associated with individual cells of the nematode, Caenorhabditis elegans.

  10. A multi-endpoint, high-throughput study of nanomaterial toxicity in Caenorhabditis elegans

    OpenAIRE

    Jung, Sang-Kyu; Qu, Xiaolei; Aleman-Meza, Boanerges; Wang, Tianxiao; Riepe, Celeste; Liu, Zheng; Li, Qilin; Zhong, Weiwei

    2015-01-01

    The booming nanotech industry has raised public concerns about the environmental health and safety impact of engineered nanomaterials (ENMs). High-throughput assays are needed to obtain toxicity data for the rapidly increasing number of ENMs. Here we present a suite of high-throughput methods to study nanotoxicity in intact animals using Caenorhabditis elegans as a model. At the population level, our system measures food consumption of thousands of animals to evaluate population fitness. At t...

  11. Toward a physical map of the genome of the nematode Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Coulson, A.; Sulston, J.; Brenner, S.; Karn, J.

    1986-10-01

    A technique for digital characterization and comparison of DNA fragments, using restriction enzymes, is described. The technique is being applied to fragments from the nematode Caenorhabditis elegans (i) to facilitate cross-indexing of clones emanating from different laboratories and (ii) to construct a physical map of the genome. Eight hundred sixty clusters of clones, from 35 to 350 kilobases long and totaling about 60% of the genome, have been characterized.

  12. Transcriptomic and proteomic analysis of anhydrobiosis in Panagrolaimus superbus and Caenorhabditis elegans dauer larvae

    OpenAIRE

    Mulvihill, Eoin

    2014-01-01

    Many organisms are able to survive the loss of up to 95% of their cellular fluid by entering a state of suspended animation known as anhydrobiosis. The mechanisms which allow these organisms to survive desiccation are poorly understood. The nematodes Panagrolaimus superbus and Caenorhabditis elegans are able to survive extreme desiccation. These nematodes have contrasting strategies for surviving desiccation perhaps defined by the habitats in which they evolved. P. superbus was...

  13. Dissection of Cell Division Processes in the One Cell Stage Caenorhabditis elegans Embryo by Mutational Analysis

    OpenAIRE

    Gönczy, Pierre; Schnabel, Heinke; Kaletta, Titus; Amores, Ana Duran; Hyman, Tony; Schnabel, Ralf

    1999-01-01

    To identify novel components required for cell division processes in complex eukaryotes, we have undertaken an extensive mutational analysis in the one cell stage Caenorhabditis elegans embryo. The large size and optical properties of this cell permit observation of cell division processes with great detail in live specimens by simple differential interference contrast (DIC) microscopy. We have screened an extensive collection of maternal-effect embryonic lethal mutations on chromosome III wi...

  14. A Tissue-Specific Approach to the Analysis of Metabolic Changes in Caenorhabditis elegans

    OpenAIRE

    Jürgen Hench; Ivana Bratić Hench; Claire Pujol; Sabine Ipsen; Susanne Brodesser; Arnaud Mourier; Markus Tolnay; Stephan Frank; Aleksandra Trifunović

    2011-01-01

    The majority of metabolic principles are evolutionarily conserved from nematodes to humans. Caenorhabditis elegans has widely accelerated the discovery of new genes important to maintain organismic metabolic homeostasis. Various methods exist to assess the metabolic state in worms, yet they often require large animal numbers and tend to be performed as bulk analyses of whole worm homogenates, thereby largely precluding a detailed studies of metabolic changes in specific worm tissues. Here, we...

  15. Ascaroside Expression in Caenorhabditis elegans Is Strongly Dependent on Diet and Developmental Stage

    OpenAIRE

    Fatma Kaplan; Jagan Srinivasan; Parag Mahanti; Ramadan Ajredini; Omer Durak; Rathika Nimalendran; Paul W. Sternberg; Teal, Peter E. A.; Schroeder, Frank C.; EDISON, ARTHUR S.; Alborn, Hans T.

    2011-01-01

    Background: The ascarosides form a family of small molecules that have been isolated from cultures of the nematode Caenorhabditis elegans. They are often referred to as “dauer pheromones” because most of them induce formation of long-lived and highly stress resistant dauer larvae. More recent studies have shown that ascarosides serve additional functions as social signals and mating pheromones. Thus, ascarosides have multiple functions. Until now, it has been generally assumed that ascaros...

  16. Ascaroside activity in Caenorhabditis elegans is highly dependent on chemical structure

    OpenAIRE

    Hollister, Kyle A.; Conner, Elizabeth S.; Zhang, Xinxing; Spell, Mark; Bernard, Gary M.; Patel, Pratik; de Carvalho, Ana Carolina G.V.; Butcher, Rebecca A.; Ragains, Justin R.

    2013-01-01

    The nematode Caenorhabditis elegans secretes ascarosides, structurally diverse derivatives of the 3,6-dideoxysugar ascarylose, and uses them in chemical communication. At high population densities, specific ascarosides, which are together known as the dauer pheromone, trigger entry into the stress-resistant dauer larval stage. In order to study the structure-activity relationships for the ascarosides, we synthesized a panel of ascarosides and tested them for dauer-inducing activity. This pane...

  17. Ascaroside expression in Caenorhabditis elegans is strongly dependent on diet and developmental stage.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available BACKGROUND: The ascarosides form a family of small molecules that have been isolated from cultures of the nematode Caenorhabditis elegans. They are often referred to as "dauer pheromones" because most of them induce formation of long-lived and highly stress resistant dauer larvae. More recent studies have shown that ascarosides serve additional functions as social signals and mating pheromones. Thus, ascarosides have multiple functions. Until now, it has been generally assumed that ascarosides are constitutively expressed during nematode development. METHODOLOGY/PRINCIPAL FINDINGS: Cultures of C. elegans were developmentally synchronized on controlled diets. Ascarosides released into the media, as well as stored internally, were quantified by LC/MS. We found that ascaroside biosynthesis and release were strongly dependent on developmental stage and diet. The male attracting pheromone was verified to be a blend of at least four ascarosides, and peak production of the two most potent mating pheromone components, ascr#3 and asc#8 immediately preceded or coincided with the temporal window for mating. The concentration of ascr#2 increased under starvation conditions and peaked during dauer formation, strongly supporting ascr#2 as the main population density signal (dauer pheromone. After dauer formation, ascaroside production largely ceased and dauer larvae did not release any ascarosides. These findings show that both total ascaroside production and the relative proportions of individual ascarosides strongly correlate with these compounds' stage-specific biological functions. CONCLUSIONS/SIGNIFICANCE: Ascaroside expression changes with development and environmental conditions. This is consistent with multiple functions of these signaling molecules. Knowledge of such differential regulation will make it possible to associate ascaroside production to gene expression profiles (transcript, protein or enzyme activity and help to determine genetic

  18. Phenotypic and Behavioral Defects Induced by Iron Exposure Can Be Transferred to Progeny in Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

    YA-OU HU; YANG WANG; BO-PING YE; DA-YONG WANG

    2008-01-01

    Previous work has showed that excess iron accumulation is harmful to reproduction and even promotes death;however,whether the multiple biological toxicity of iron (Fe) exposure could be transferred to progeny remains unknown.The present study used Caenorhabditis elegans to analyze the multiple toxicities of iron exposure and their possible transferable properties.Methods Three concentrations of iron sulfate solution (2.5μmol/L,75μmol/L,and 200 lamol/L) were used.The endpoints of lifespan,body size,generation time,brood size,head thrash and body bend frequencies,and chemotaxis plasticity were selected to investigate Fe toxicity and its effect on progeny in Caenorhabditis elegans.Results The Fe toxicity could cause multiple biological defects in a dose-dependent manner by affecting different endpoints in nematodes.Most of the multiple biological defects and behavior toxicities could be transferred from Fe-exposed Caenorhabditis elegans to their progeny.Compared to the parents,no recovery phenotypes were observed for some of the defects in the progeny,such as body bend frequency and life span.We further summarized the defects caused by Fe exposure into 2 groups according to their transferable properties.Conclusion Our results suggest that Fe exposure could cause multiple biological defects,and most of these severe defects could be transferred from Fe exposed nematodes to their progeny.

  19. The neuropeptide NLP-22 regulates a sleep-like state in Caenorhabditis elegans.

    Science.gov (United States)

    Nelson, M D; Trojanowski, N F; George-Raizen, J B; Smith, C J; Yu, C-C; Fang-Yen, C; Raizen, D M

    2013-01-01

    Neuropeptides have central roles in the regulation of homoeostatic behaviours such as sleep and feeding. Caenorhabditis elegans displays sleep-like quiescence of locomotion and feeding during a larval transition stage called lethargus and feeds during active larval and adult stages. Here we show that the neuropeptide NLP-22 is a regulator of Caenorhabditis elegans sleep-like quiescence observed during lethargus. nlp-22 shows cyclical mRNA expression in synchrony with lethargus; it is regulated by LIN-42, an orthologue of the core circadian protein PERIOD; and it is expressed solely in the two RIA interneurons. nlp-22 and the RIA interneurons are required for normal lethargus quiescence, and forced expression of nlp-22 during active stages causes anachronistic locomotion and feeding quiescence. Optogenetic stimulation of the RIA interneurons has a movement-promoting effect, demonstrating functional complexity in a single-neuron type. Our work defines a quiescence-regulating role for NLP-22 and expands our knowledge of the neural circuitry controlling Caenorhabditis elegans behavioural quiescence.

  20. Genome-wide identification of lineage-specific genes within Caenorhabditis elegans.

    Science.gov (United States)

    Zhou, Kun; Huang, Beibei; Zou, Ming; Lu, Dandan; He, Shunping; Wang, Guoxiu

    2015-10-01

    With the rapid growth of sequencing technology, a number of genomes and transcriptomes of various species have been sequenced, contributing to the study of lineage-specific genes (LSGs). We identified two sets of LSGs using BLAST: one included Caenorhabditis elegans species-specific genes (1423, SSGs), and the other consisted of Caenorhabditis genus-specific genes (4539, GSGs). The subsequent characterization and analysis of the SSGs and GSGs showed that they have significant differences in evolution and that most LSGs were generated by gene duplication and integration of transposable elements (TEs). We then performed temporal expression profiling and protein function prediction and observed that many SSGs and GSGs are expressed and that genes involved with sex determination, specific stress, immune response, and morphogenesis are over-represented, suggesting that these specific genes may be related to the Caenorhabditis nematodes' special ability to survive in severe and extreme environments.

  1. Data in support of genome-wide identification of lineage-specific genes within Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Kun Zhou

    2015-09-01

    Full Text Available Two sets of LSGs were identified using BLAST: Caenorhabditis elegans species-specific genes (SSGs, 1423, and Caenorhabditis genus-specific genes (GSGs, 4539. The data contained in this article show SSGs and GSGs have significant differences in evolution and that most of them were formed by gene duplication and integration of transposable elements (TEs. Subsequent observation of temporal expression and protein function presents that many SSGs and GSGs are expressed and that genes involved with sex determination, specific stress, immune response, and morphogenesis are most represented. The data are related to research article “Genome-wide identification of lineage-specific genes within Caenorhabditis elegans” in Journal of Genomics [1].

  2. Neurons refine the Caenorhabditis elegans body plan by directing axial patterning by Wnts.

    Directory of Open Access Journals (Sweden)

    Katarzyna Modzelewska

    Full Text Available Metazoans display remarkable conservation of gene families, including growth factors, yet somehow these genes are used in different ways to generate tremendous morphological diversity. While variations in the magnitude and spatio-temporal aspects of signaling by a growth factor can generate different body patterns, how these signaling variations are organized and coordinated during development is unclear. Basic body plans are organized by the end of gastrulation and are refined as limbs, organs, and nervous systems co-develop. Despite their proximity to developing tissues, neurons are primarily thought to act after development, on behavior. Here, we show that in Caenorhabditis elegans, the axonal projections of neurons regulate tissue progenitor responses to Wnts so that certain organs develop with the correct morphology at the right axial positions. We find that foreshortening of the posteriorly directed axons of the two canal-associated neurons (CANs disrupts mid-body vulval morphology, and produces ectopic vulval tissue in the posterior epidermis, in a Wnt-dependent manner. We also provide evidence that suggests that the posterior CAN axons modulate the location and strength of Wnt signaling along the anterior-posterior axis by employing a Ror family Wnt receptor to bind posteriorly derived Wnts, and hence, refine their distributions. Surprisingly, despite high levels of Ror expression in many other cells, these cells cannot substitute for the CAN axons in patterning the epidermis, nor can cells expressing a secreted Wnt inhibitor, SFRP-1. Thus, unmyelinated axon tracts are critical for patterning the C. elegans body. Our findings suggest that the evolution of neurons not only improved metazoans by increasing behavioral complexity, but also by expanding the diversity of developmental patterns generated by growth factors such as Wnts.

  3. Lifespan-extending effects of royal jelly and its related substances on the nematode Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Yoko Honda

    Full Text Available BACKGROUND: One of the most important challenges in the study of aging is to discover compounds with longevity-promoting activities and to unravel their underlying mechanisms. Royal jelly (RJ has been reported to possess diverse beneficial properties. Furthermore, protease-treated RJ (pRJ has additional pharmacological activities. Exactly how RJ and pRJ exert these effects and which of their components are responsible for these effects are largely unknown. The evolutionarily conserved mechanisms that control longevity have been indicated. The purpose of the present study was to determine whether RJ and its related substances exert a lifespan-extending function in the nematode Caenorhabditis elegans and to gain insights into the active agents in RJ and their mechanism of action. PRINCIPAL FINDINGS: We found that both RJ and pRJ extended the lifespan of C. elegans. The lifespan-extending activity of pRJ was enhanced by Octadecyl-silica column chromatography (pRJ-Fraction 5. pRJ-Fr.5 increased the animals' lifespan in part by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS. pRJ-Fr.5 reduced the expression of ins-9, one of the insulin-like peptide genes. Moreover, pRJ-Fr.5 and reduced IIS shared some common features in terms of their effects on gene expression, such as the up-regulation of dod-3 and the down-regulation of dod-19, dao-4 and fkb-4. 10-Hydroxy-2-decenoic acid (10-HDA, which was present at high concentrations in pRJ-Fr.5, increased lifespan independently of DAF-16 activity. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that RJ and its related substances extend lifespan in C. elegans, suggesting that RJ may contain longevity-promoting factors. Further analysis and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network involved in longevity regulation in diverse

  4. Mutations in the clk-1 gene of Caenorhabditis elegans affect developmental and behavioral timing

    Energy Technology Data Exchange (ETDEWEB)

    Wong, A.; Boutis, P.; Hekimi, S. [McGill Univ., Quebec (Canada)

    1995-03-01

    We have identified three allelic, maternal-effect mutations that affect developmental and behavioral timing in Caenorhabditis elegans. They result in a mean lengthening of embryonic and postembryonic development, the cell cycle period and life span, as well as the periods of the defecation, swimming and pumping cycles. These mutants also display a number of additional phenotypes related to timing. For example, the variability in the length of embryonic development is several times larger in the mutants than in the wild type, resulting in the occasional production of mutant embryos developing more rapidly than the most rapidly developing wild-type embryos. In addition, the duration of embryonic development of the mutants, but not of the wild type, depends on the temperature at which their parents were raised. Finally, individual variations in the severity of distinct mutant phenotypes are correlated in a counterintuitive way. For example, the animals with the shortest embryonic development have the longest defecation cycle and those with the longest embryonic development have the shortest defecation cycle. Most of the features affected by these mutations are believed to be controlled by biological clocks, and we therefore call the gene defined by these mutations clk-1, for {open_quotes}abnormal function of biological clocks.{close_quotes} 52 refs., 5 figs., 4 tabs.

  5. Effects of genetic mutations and chemical exposures on Caenorhabditis elegans feeding: evaluation of a novel, high-throughput screening assay.

    Directory of Open Access Journals (Sweden)

    Windy A Boyd

    Full Text Available BACKGROUND: Government agencies have defined a need to reduce, refine or replace current mammalian-based bioassays with testing methods that use alternative species. Invertebrate species, such as Caenorhabditis elegans, provide an attractive option because of their short life cycles, inexpensive maintenance, and high degree of evolutionary conservation with higher eukaryotes. The C. elegans pharynx is a favorable model for studying neuromuscular function, and the effects of chemicals on neuromuscular activity, i.e., feeding. Current feeding methodologies, however, are labor intensive and only semi-quantitative. METHODOLOGY/PRINCIPAL FINDINGS: Here a high-throughput assay is described that uses flow cytometry to measure C. elegans feeding by determining the size and intestinal fluorescence of hundreds of nematodes after exposure to fluorescent-labeled microspheres. This assay was validated by quantifying fluorescence in feeding-defective C. elegans (eat mutants, and by exposing wild-type nematodes to the neuroactive compounds, serotonin and arecoline. The eat mutations previously determined to cause slow pumping rates exhibited the lowest feeding levels with our assay. Concentration-dependent increases in feeding levels after serotonin exposures were dependent on food availability, while feeding levels decreased in arecoline-exposed nematodes regardless of the presence of food. The effects of the environmental contaminants, cadmium chloride and chlorpyrifos, on wild-type C. elegans feeding were then used to demonstrate an application of the feeding assay. Cadmium exposures above 200 microM led to a sharp drop in feeding levels. Feeding of chlorpyrifos-exposed nematodes decreased in a concentration-dependent fashion with an EC(50 of 2 microM. CONCLUSIONS/SIGNIFICANCE: The C. elegans fluorescence microsphere feeding assay is a rapid, reliable method for the assessment of neurotoxic effects of pharmaceutical drugs, industrial chemicals or

  6. Levamisole resistance resolved at the single-channel level in Caenorhabditis elegans

    Science.gov (United States)

    Qian, Hai; Robertson, Alan P.; Powell-Coffman, Jo Anne; Martin, Richard J.

    2008-01-01

    Sydney Brenner promoted Caenorhabditis elegans as a model organism, and subsequent investigations pursued resistance to the nicotinic anthelmintic drug levamisole in C. elegans at a genetic level. These studies have advanced our understanding of genes associated with neuromuscular transmission and resistance to the antinematodal drug. In lev-8 and lev-1 mutant C. elegans, levamisole resistance is associated with reductions in levamisole-activated whole muscle cell currents. Although lev-8 and lev-1 are known to code for nicotinic acetylcholine receptor (nAChR) subunits, an explanation for why these currents get smaller is not available. In wild-type adults, nAChRs aggregate at neuromuscular junctions and are not accessible for single-channel recording. Here we describe a use of LEV-10 knockouts, in which aggregation is lost, to make in situ recordings of nAChR channel currents. Our observations provide an explanation for levamisole resistance produced by LEV-8 and LEV-1 mutants at the single-channel level.—Qian, H., Robertson, A. P., Powell-Coffman, J. A., and Martin, R. J. Levamisole resistance resolved at the single-channel level in Caenorhabditis elegans. PMID:18519804

  7. Insights into the Ecotoxicity of Silver Nanoparticles Transferred from Escherichia coli to Caenorhabditis elegans

    Science.gov (United States)

    Luo, Xun; Xu, Shengmin; Yang, Yaning; Li, Luzhi; Chen, Shaopeng; Xu, An; Wu, Lijun

    2016-11-01

    Previous studies have indicated that engineered nanomaterials can be transferred through the food chain. However, their potential ecotoxicity to the environment is not fully understood. Here, we systematically evaluated the physiological behavior and toxicity of polyvinylpyrrolidone (PVP)-coated silver nanoparticles (AgNPs) using a food chain model from Escherichia coli (E. coli) to Caenorhabditis elegans (C. elegans). Our results demonstrated that AgNPs accumulated in E. coli could be transferred to the C. elegans, and AgNPs were clearly distributed in the gut lumen, subcutaneous tissue and gonad. After being transferred to C. elegans through the food chain, the accumulated AgNPs caused serious toxicity to the higher trophic level (C. elegans), including effects on germ cell death, reproductive integrity and life span. Relative to larger particles (75 nm), small AgNPs (25 nm) more easily accumulated in the food chain and exhibited a stronger toxicity to the higher trophic level. More importantly, both the AgNPs that had accumulated in C. elegans through the food chain and the resulting impairment of germ cells could be transferred to the next generation, indicating that AgNP can cause genetic damage across generations. Our findings highlight that nanomaterials pose potential ecotoxicity to ecosystems via transport through the food chain.

  8. Differential effects of resveratrol and SRT1720 on lifespan of adult Caenorhabditis elegans.

    Science.gov (United States)

    Zarse, K; Schmeisser, S; Birringer, M; Falk, E; Schmoll, D; Ristow, M

    2010-11-01

    Resveratrol and SRT1720 have been shown to act as sirtuin activators that may ameliorate type 2 diabetes and metabolic diseases in mice. Moreover, resveratrol extends lifespan in model organisms like C. elegans, N. FURZERI, and possibly D. melanogaster. The aim of the study was to test whether pharmacological concentrations of resveratrol and SRT1720 are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Several hundreds of adult C. ELEGANS roundworms were maintained on agar plates and fed E. COLI strain OP50 bacteria. Resveratrol (5 micromolar, 500 nanomolar) or SRT1720 (1 micromolar, 100 nanomolar) was applied to the agar to test whether they may promote longevity by quantifying survival in the presence and absence of the respective compounds. At a dose of 5 micromolar, which is pharmacologically relevant and 20 times lower than previously published concentrations, resveratrol significantly extends C. elegans lifespan by 3.6% (mean lifespan) and 3.4% (maximum lifespan). By unexpected contrast, SRT1720, which was previously proposed to be several hundred times more active than resveratrol, did not extend lifespan at none of the concentrations tested. Thus, in the model organisms C. elegans, resveratrol is capable of promoting longevity at a concentration that pharmacologically relevant and 20 times lower than previously published doses. The sirtuin activator SRT1720 did not extend lifespan, suggesting that in C. elegans, some relevant effects of resveratrol cannot be mimicked by SRT1720.

  9. Elucidating the Mechanism of Weissella-dependent Lifespan Extension in Caenorhabditis elegans.

    Science.gov (United States)

    Lee, Jiyun; Kwon, Gayeung; Lim, Young-Hee

    2015-11-25

    The mechanism whereby lactic acid bacteria extend the lifespan of Caenorhabditis elegans has previously been elucidated. However, the role of Weissella species has yet not been studied. We show that Weissella koreensis and Weissella cibaria significantly (p OP50 and induce the expression of several genes related to lifespan extension (daf-16, aak-2, jnk-1, sod-3 and hif-1). Oral administration of Weissella altered reactive oxygen species (ROS) production and lowered the accumulation of lipofuscin and increased locomotor activity (which translates to a delay in ageing). Moreover, Weissella-fed C. elegans had decreased body sizes, brood sizes, ATP levels and pharyngeal pumping rates compared with E. coli OP50-fed worms. Furthermore, mutations in sod-3, hif-1 or skn-1 did not alter lifespan extension compared with wild-type C. elegans. However, C. elegans failed to display lifespan extension in loss-of-function mutants of daf-16, aak-2 and jnk-1, which highlights the potential role of these genes in Weissella-induced longevity in C. elegans. Weissella species extend C. elegans lifespan by activating DAF-16 via the c-Jun N-terminal kinase (JNK) pathway, which is related to stress response, and the AMP-activated protein kinase (AMPK)-pathway that is activated by dietary restriction.

  10. Killing of Caenorhabditis elegans by Cryptococcus neoformans as a model of yeast pathogenesis.

    Science.gov (United States)

    Mylonakis, Eleftherios; Ausubel, Frederick M; Perfect, John R; Heitman, Joseph; Calderwood, Stephen B

    2002-11-26

    We found that the well-studied nematode Caenorhabditis elegans can use various yeasts, including Cryptococcus laurentii and Cryptococcus kuetzingii, as a sole source of food, producing similar brood sizes compared with growth on its usual laboratory food source Escherichia coli OP50. C. elegans grown on these yeasts had a life span similar to (C. laurentii) or longer than (C. kuetzingii) those fed on E. coli. However, the human pathogenic yeast Cryptococcus neoformans killed C. elegans, and the C. neoformans polysaccharide capsule as well as several C. neoformans genes previously shown to be involved in mammalian virulence were also shown to play a role in C. elegans killing. These included genes associated with signal transduction pathways (GPA1, PKA1, PKR1, and RAS1), laccase production (LAC1), and the alpha mating type. C. neoformans adenine auxotrophs, which are less virulent in mammals, were also less virulent in C. elegans. These results support the model that mammalian pathogenesis of C. neoformans may be a consequence of adaptations that have evolved during the interaction of C. neoformans with environmental predators such as free-living nematodes and amoebae and suggest that C. elegans can be used as a simple model host in which C. neoformans pathogenesis can be readily studied.

  11. A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Choi, Jae Im; Yoon, Kyoung-Hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin

    2016-03-01

    Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator-prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds.

  12. The nematode Caenorhabditis elegans as an integrated toxicological tool to assess water quality and pollution.

    Science.gov (United States)

    Clavijo, Araceli; Kronberg, María Florencia; Rossen, Ariana; Moya, Aldana; Calvo, Daniel; Salatino, Santa Esmeralda; Pagano, Eduardo Antonio; Morábito, José Antonio; Munarriz, Eliana Rosa

    2016-11-01

    Determination of water quality status in rivers is critical to establish a sustainable water management policy. For this reason, over the last decades it has been recommended to perform integrated water assessments that include water quantities and physicochemical, ecological and toxicological tests. However, sometimes resources are limited and it is not possible to perform large-scale chemical determinations of pollutants or conduct numerous ecotoxicological tests. To overcome this problem we use and measure the growth, as a response parameter, of the soil nematode Caenorhabditis elegans to assess water quality in rivers. The C. elegans is a ubiquitous organism that has emerged as an important model organism in aquatic and soil toxicology research. The Tunuyán River Basin (Province of Mendoza, Argentina) has been selected as a representative traditional water monitoring system to test the applicability of the C. elegans toxicological bioassay to generate an integrated water quality evaluation. Jointly with the C. elegans toxic assays, physicochemical and bacteriological parameters were determined for each monitoring site. C. elegans bioassays help to identify different water qualities in the river basin. Multivariate statistical analysis (PCA and linear regression models) has allowed us to confirm that traditional water quality studies do not predict potential toxic effects on living organisms. On the contrary, physicochemical and bacteriological analyzes explain water quality threats. Our results confirm that the C. elegans bioassay is a sensible and suitable tool to assess toxicity and should be implemented in routine water quality monitoring.

  13. Physiological and Immunological Regulations in Caenorhabditis elegans Infected with Salmonella enterica serovar Typhi.

    Science.gov (United States)

    Sivamaruthi, Bhagavathi Sundaram; Balamurugan, Krishnaswamy

    2014-03-01

    Studies pertaining to Salmonella enterica serovar Typhimurium infection by utilizing model systems failed to mimic the essential aspects of immunity induced by Salmonella enterica serovar Typhi, as the determinants of innate immunity are distinct. The present study investigated the physiological and innate immune responses of S. Typhi infected Caenorhabditis elegans and also explored the Ty21a mediated immune enhancement in C. elegans. Ty21a is a known live vaccine for typhoidal infection in human beings. Physiological responses of C. elegans infected with S. Typhi assessed by survival and behavioral assays revealed that S. Typhi caused host mortality by persistent infection. However, Ty21a exposure to C. elegans was not harmful. Ty21a pre-exposed C. elegans, exhibited significant resistance against S. Typhi infection. Elevated accumulation of S. Typhi inside the infected host was observed when compared to Ty21a exposures. Transcript analysis of candidate innate immune gene (clec-60, clec-87, lys-7, ilys-3, scl-2, cpr-2, F08G5.6, atf-7, age-1, bec-1 and daf-16) regulations in the host during S. Typhi infection have been assessed through qPCR analysis to understand the activation of immune signaling pathways during S. Typhi infections. Gene silencing approaches confirmed that clec-60 and clec-87 has a major role in the defense system of C. elegans during S. Typhi infection. In conclusion, the study revealed that preconditioning of host with Ty21a protects against subsequent S. Typhi infection.

  14. Identification of gamma-aminobutyric acid and its binding sites in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Schaeffer, J.M.; Bergstrom, A.R.

    1988-01-01

    Gamma-aminobutyric acid (GABA), glutamate decarboxylase and GABA-transaminase were identified in the nematode Caenorhabditis elegans. The concentration of GABA in C. elegans is approximately 10-fold lower than the concentration of GABA in rat brain. Glutamate decarboxylase and GABA-transaminase, the GABA anabolic and catabolic enzymes, are also present in C. elegans. Crude membrane fractions were prepared from C. elegans and used to study specific (/sup 3/H) GABA binding sites. GABA binds to C. elegans membranes with high affinity and low capacity. Muscimol is a competitive inhibitor of specific GABA binding with a K/sub I/ value of 120 nM. None of the other GABA agonists or antagonists inhibited greater than 40% of the specific GABA binding at concentrations up to 10/sup -4/M. Thirteen spider venoms were examined as possible GABA agonists or antagonists, the venom from Calilena agelenidae inhibits specific GABA binding with a K/sub I/ value of 6 nl/ml. These results suggest that GABA has a physiological role as a neurotransmitter in C. elegans.

  15. Monascus-fermented dioscorea enhances oxidative stress resistance via DAF-16/FOXO in Caenorhabditis elegans.

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    Yeu-Ching Shi

    Full Text Available BACKGROUND: Monascus-fermented products are mentioned in an ancient Chinese pharmacopoeia of medicinal food and herbs. Monascus-fermented products offer valuable therapeutic benefits and have been extensively used in East Asia for several centuries. Several biological activities of Monascus-fermented products were recently described, and the extract of Monascus-fermented products showed strong antioxidant activity of scavenging DPPH radicals. To evaluate whether Monascus-fermented dioscorea products have potential as nutritional supplements, Monascus-fermented dioscorea's modulation of oxidative-stress resistance and associated regulatory mechanisms in Caenorhabditis elegans were investigated. PRINCIPAL FINDINGS: We examined oxidative stress resistance of the ethanol extract of red mold dioscorea (RMDE in C. elegans, and found that RMDE-treated wild-type C. elegans showed an increased survival during juglone-induced oxidative stress compared to untreated controls, whereas the antioxidant phenotype was absent from a daf-16 mutant. In addition, the RMDE reduced the level of intracellular reactive oxygen species in C. elegans. Finally, the RMDE affected the subcellular distribution of the FOXO transcription factor, DAF-16, in C. elegans and induced the expression of the sod-3 antioxidative gene. CONCLUSIONS: These findings suggest that the RMDE acts as an antioxidative stress agent and thus may have potential as a nutritional supplement. Further studies in C. elegans suggest that the antioxidant effect of RMDE is mediated via regulation of the DAF-16/FOXO-dependent pathway.

  16. Revelations from the Nematode Caenorhabditis elegans on the Complex Interplay of Metal Toxicological Mechanisms

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    Ebany J. Martinez-Finley

    2011-01-01

    Full Text Available Metals have been definitively linked to a number of disease states. Due to the widespread existence of metals in our environment from both natural and anthropogenic sources, understanding the mechanisms of their cellular detoxification is of upmost importance. Organisms have evolved cellular detoxification systems including glutathione, metallothioneins, pumps and transporters, and heat shock proteins to regulate intracellular metal levels. The model organism, Caenorhabditis elegans (C. elegans, contains these systems and provides several advantages for deciphering the mechanisms of metal detoxification. This review provides a brief summary of contemporary literature on the various mechanisms involved in the cellular detoxification of metals, specifically, antimony, arsenic, cadmium, copper, manganese, mercury, and depleted uranium using the C. elegans model system for investigation and analysis.

  17. Reference toxicants for toxicity testing using Caenorhabditis elegans in aquatic media

    Energy Technology Data Exchange (ETDEWEB)

    Cressman, C.P. III; Williams, P.L. [Univ. of Georgia, Athens, GA (United States)

    1997-09-01

    Caenorhabditis elegans aquatic toxicity assays were standardized with five common reference toxicants: CdCl{sub 2}, NaCl, KCl, sodium lauryl sulfate (SLS), and sodium pentachlorophenate (PCP). Aquatic toxicity testing was conducted in 3 media: a standard C. elegans medium; EPA moderately hard reconstituted water; and EPA moderately hard mineral water. Test duration in each medium was 24h without a food source, and 24h and 48h with Escherichia coli strain OP50 as a food source. Each test was replicated three times with each replicate having 6 wells per concentration, 10 worms per well. LC{sub 50} values were calculated using probit analysis. The average LC{sub 50}s for each set of replications were compared to assess sensitivity and reproducibility of the data, identifying expected variation between replicate tests. These reference toxicants increase the database for C. elegans and provide a benchmark for further application.

  18. Caenorhabditis elegans selects distinct crawling and swimming gaits via dopamine and serotonin.

    Science.gov (United States)

    Vidal-Gadea, Andrés; Topper, Stephen; Young, Layla; Crisp, Ashley; Kressin, Leah; Elbel, Erin; Maples, Thomas; Brauner, Martin; Erbguth, Karen; Axelrod, Abram; Gottschalk, Alexander; Siegel, Dionicio; Pierce-Shimomura, Jonathan T

    2011-10-18

    Many animals, including humans, select alternate forms of motion (gaits) to move efficiently in different environments. However, it is unclear whether primitive animals, such as nematodes, also use this strategy. We used a multifaceted approach to study how the nematode Caenorhabditis elegans freely moves into and out of water. We demonstrate that C. elegans uses biogenic amines to switch between distinct crawling and swimming gaits. Dopamine is necessary and sufficient to initiate and maintain crawling after swimming. Serotonin is necessary and sufficient to transition from crawling to swimming and to inhibit a set of crawl-specific behaviors. Further study of locomotory switching in C. elegans and its dependence on biogenic amines may provide insight into how gait transitions are performed in other animals.

  19. Inducing RNAi in Caenorhabditis elegans by Injection of dsRNA.

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    Hammell, Christopher M; Hannon, Gregory J

    2016-01-04

    In Caenorhabditis elegans, long double-stranded RNAs (dsRNAs) are overwhelmingly the trigger of choice for inducing RNA interference (RNAi). Although injection of dsRNA into the somatic or germline tissues of animals requires both specific equipment and technical skills, the ability of C. elegans to amplify the initial dsRNA trigger and to transmit the RNAi activity to other somatic tissues and to the progeny of injected animals is one of the main advantages of using C. elegans as a model system. The direct injection of dsRNA into parental animals is the most reliable method for RNAi and also presents the least experiment-to-experiment and animal-to-animal variability.

  20. Scorpion Venom Heat-Resistant Peptide Protects Transgenic Caenorhabditis elegans from β- Amyloid Toxicity

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    Xiao-Gang Zhang

    2016-07-01

    Full Text Available Scorpion venom heat-resistant peptide (SVHRP is a component purified from Buthus martensii Karsch scorpion venom. Our previous studies found SVHRP could enhance neurogenesis and inhibit microglia-mediated neuroinflammation in vivo. Here, we use the transgenic CL4176, CL2006 and CL2355 strains of Caenorhabditis elegans which express the human Aβ1–42 to investigate the effects and the possible mechanisms of SVHRP mediated protection against Aβ toxicity in vivo. The results showed that SVHRP-fed worms displayed remarkably decreased paralysis, less abundant toxic Aβ oligomers, reduced Aβ plaque deposition with respect to untreated animals. SVHRP also suppressed neuronal Aβ expression-induced defects in chemotaxis behavior and attenuated levels of ROS in the transgenic C. elegans. Taken together, these results suggest SVHRP could protect against Aβ-induced toxicity in C. elegans. Further studies need to be conducted in murine models and humans to analyze the effectiveness of the peptide.

  1. Scorpion Venom Heat-Resistant Peptide Protects Transgenic Caenorhabditis elegans from β-Amyloid Toxicity

    Science.gov (United States)

    Zhang, Xiao-Gang; Wang, Xi; Zhou, Ting-Ting; Wu, Xue-Fei; Peng, Yan; Zhang, Wan-Qin; Li, Shao; Zhao, Jie

    2016-01-01

    Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Our previous studies found SVHRP could enhance neurogenesis and inhibit microglia-mediated neuroinflammation in vivo. Here, we use the transgenic CL4176, CL2006, and CL2355 strains of Caenorhabditis elegans which express the human Aβ1-42 to investigate the effects and the possible mechanisms of SVHRP mediated protection against Aβ toxicity in vivo. The results showed that SVHRP-fed worms displayed remarkably decreased paralysis, less abundant toxic Aβ oligomers, reduced Aβ plaque deposition with respect to untreated animals. SVHRP also suppressed neuronal Aβ expression-induced defects in chemotaxis behavior and attenuated levels of ROS in the transgenic C. elegans. Taken together, these results suggest SVHRP could protect against Aβ-induced toxicity in C. elegans. Further studies need to be conducted in murine models and humans to analyze the effectiveness of the peptide. PMID:27507947

  2. The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length

    Science.gov (United States)

    Cook, Daniel E.; Zdraljevic, Stefan; Tanny, Robyn E.; Seo, Beomseok; Riccardi, David D.; Noble, Luke M.; Rockman, Matthew V.; Alkema, Mark J.; Braendle, Christian; Kammenga, Jan E.; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C.

    2016-01-01

    Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. PMID:27449056

  3. The nephronophthisis-related gene ift-139 is required for ciliogenesis in Caenorhabditis elegans

    Science.gov (United States)

    Niwa, Shinsuke

    2016-01-01

    Defects in cilia cause a spectrum of diseases known as ciliopathies. Nephronophthisis, a ciliopathy, is the most common genetic cause of renal disease. Here, I cloned and analysed a nephronophthisis-related gene ift-139 in Caenorhabditis elegans. ift-139 was exclusively expressed in ciliated neurons in C. elegans. Genetic and cellular analyses suggest that ift-139 plays a role in retrograde intraflagellar transport and is required for cilia formation. A homologous point mutation that causes ciliopathy disrupted the function of ift-139 in C. elegans. ift-139 is an orthologue of human TTC21B, mutations in which are known to cause nephronophthisis 12 and short-rib thoracic dysplasia 4. These results suggest that ift-139 is evolutionarily conserved and fundamental to the formation of cilia. PMID:27515926

  4. The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length.

    Science.gov (United States)

    Cook, Daniel E; Zdraljevic, Stefan; Tanny, Robyn E; Seo, Beomseok; Riccardi, David D; Noble, Luke M; Rockman, Matthew V; Alkema, Mark J; Braendle, Christian; Kammenga, Jan E; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C

    2016-09-01

    Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans.

  5. l-Arginine Enhances Resistance against Oxidative Stress and Heat Stress in Caenorhabditis elegans

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    Heran Ma

    2016-09-01

    Full Text Available The antioxidant properties of l-arginine (l-Arg in vivo, and its effect on enhancing resistance to oxidative stress and heat stress in Caenorhabditis elegans were investigated. C. elegans, a worm model popularly used in molecular and developmental biology, was used in the present study. Here, we report that l-Arg, at a concentration of 1 mM, prolonged C. elegans life by 26.98% and 37.02% under oxidative and heat stress, respectively. Further experiments indicated that the longevity-extending effects of l-Arg may be exerted by its free radical scavenging capacity and the upregulation of aging-associated gene expression in worms. This work is important in the context of numerous recent studies that concluded that environment stresses are associated with an increased population death rate.

  6. Bacillus subtilis biofilm extends Caenorhabditis elegans longevity through downregulation of the insulin-like signalling pathway

    Science.gov (United States)

    Donato, Verónica; Ayala, Facundo Rodríguez; Cogliati, Sebastián; Bauman, Carlos; Costa, Juan Gabriel; Leñini, Cecilia; Grau, Roberto

    2017-01-01

    Beneficial bacteria have been shown to affect host longevity, but the molecular mechanisms mediating such effects remain largely unclear. Here we show that formation of Bacillus subtilis biofilms increases Caenorhabditis elegans lifespan. Biofilm-proficient B. subtilis colonizes the C. elegans gut and extends worm lifespan more than biofilm-deficient isogenic strains. Two molecules produced by B. subtilis — the quorum-sensing pentapeptide CSF and nitric oxide (NO) — are sufficient to extend C. elegans longevity. When B. subtilis is cultured under biofilm-supporting conditions, the synthesis of NO and CSF is increased in comparison with their production under planktonic growth conditions. We further show that the prolongevity effect of B. subtilis biofilms depends on the DAF-2/DAF-16/HSF-1 signalling axis and the downregulation of the insulin-like signalling (ILS) pathway. PMID:28134244

  7. Topological cluster analysis reveals the systemic organization of the Caenorhabditis elegans connectome.

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    Yunkyu Sohn

    2011-05-01

    Full Text Available The modular organization of networks of individual neurons interwoven through synapses has not been fully explored due to the incredible complexity of the connectivity architecture. Here we use the modularity-based community detection method for directed, weighted networks to examine hierarchically organized modules in the complete wiring diagram (connectome of Caenorhabditis elegans (C. elegans and to investigate their topological properties. Incorporating bilateral symmetry of the network as an important cue for proper cluster assignment, we identified anatomical clusters in the C. elegans connectome, including a body-spanning cluster, which correspond to experimentally identified functional circuits. Moreover, the hierarchical organization of the five clusters explains the systemic cooperation (e.g., mechanosensation, chemosensation, and navigation that occurs among the structurally segregated biological circuits to produce higher-order complex behaviors.

  8. Baccoside A suppresses epileptic-like seizure/convulsion in Caenorhabditis elegans.

    Science.gov (United States)

    Pandey, Rakesh; Gupta, Shipra; Tandon, Sudeep; Wolkenhauer, Olaf; Vera, Julio; Gupta, Shailendra K

    2010-09-01

    The 1 mm long Caenorhabditis elegans is one of the prime research tools to study different human neurodegenerative diseases. We have considered the case in which increase in the surrounding temperature of this multicellular model leads to abnormal bursts of neuronal cells that can be linked to seizure or convulsion. The induction of such seizure/convulsion mechanism was done by gradually increasing the temperature with 1x buffer (100 mM NaCl, 50 mM MgCl(2)) in adult C. elegans. In the present experiment it is demonstrated that Baccoside A can significantly reduce the seizure/convulsion in C. elegans at higher temperatures (26-28+/-1 degrees C). Furthermore, in T-type Ca(2+) channel cca-1 mutant worms, no convulsion was recorded. Our experimental results suggest that plant molecules from Bacopa monnieri may be useful in suppressing the seizure/convulsion in worms.

  9. Calpains mediate integrin attachment complex maintenance of adult muscle in Caenorhabditis elegans.

    Science.gov (United States)

    Etheridge, Timothy; Oczypok, Elizabeth A; Lehmann, Susann; Fields, Brandon D; Shephard, Freya; Jacobson, Lewis A; Szewczyk, Nathaniel J

    2012-01-01

    Two components of integrin containing attachment complexes, UNC-97/PINCH and UNC-112/MIG-2/Kindlin-2, were recently identified as negative regulators of muscle protein degradation and as having decreased mRNA levels in response to spaceflight. Integrin complexes transmit force between the inside and outside of muscle cells and signal changes in muscle size in response to force and, perhaps, disuse. We therefore investigated the effects of acute decreases in expression of the genes encoding these multi-protein complexes. We find that in fully developed adult Caenorhabditis elegans muscle, RNAi against genes encoding core, and peripheral, members of these complexes induces protein degradation, myofibrillar and mitochondrial dystrophies, and a movement defect. Genetic disruption of Z-line- or M-line-specific complex members is sufficient to induce these defects. We confirmed that defects occur in temperature-sensitive mutants for two of the genes: unc-52, which encodes the extra-cellular ligand Perlecan, and unc-112, which encodes the intracellular component Kindlin-2. These results demonstrate that integrin containing attachment complexes, as a whole, are required for proper maintenance of adult muscle. These defects, and collapse of arrayed attachment complexes into ball like structures, are blocked when DIM-1 levels are reduced. Degradation is also blocked by RNAi or drugs targeting calpains, implying that disruption of integrin containing complexes results in calpain activation. In wild-type animals, either during development or in adults, RNAi against calpain genes results in integrin muscle attachment disruptions and consequent sub-cellular defects. These results demonstrate that calpains are required for proper assembly and maintenance of integrin attachment complexes. Taken together our data provide in vivo evidence that a calpain-based molecular repair mechanism exists for dealing with attachment complex disruption in adult muscle. Since C. elegans lacks

  10. Calpains mediate integrin attachment complex maintenance of adult muscle in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Timothy Etheridge

    2012-01-01

    Full Text Available Two components of integrin containing attachment complexes, UNC-97/PINCH and UNC-112/MIG-2/Kindlin-2, were recently identified as negative regulators of muscle protein degradation and as having decreased mRNA levels in response to spaceflight. Integrin complexes transmit force between the inside and outside of muscle cells and signal changes in muscle size in response to force and, perhaps, disuse. We therefore investigated the effects of acute decreases in expression of the genes encoding these multi-protein complexes. We find that in fully developed adult Caenorhabditis elegans muscle, RNAi against genes encoding core, and peripheral, members of these complexes induces protein degradation, myofibrillar and mitochondrial dystrophies, and a movement defect. Genetic disruption of Z-line- or M-line-specific complex members is sufficient to induce these defects. We confirmed that defects occur in temperature-sensitive mutants for two of the genes: unc-52, which encodes the extra-cellular ligand Perlecan, and unc-112, which encodes the intracellular component Kindlin-2. These results demonstrate that integrin containing attachment complexes, as a whole, are required for proper maintenance of adult muscle. These defects, and collapse of arrayed attachment complexes into ball like structures, are blocked when DIM-1 levels are reduced. Degradation is also blocked by RNAi or drugs targeting calpains, implying that disruption of integrin containing complexes results in calpain activation. In wild-type animals, either during development or in adults, RNAi against calpain genes results in integrin muscle attachment disruptions and consequent sub-cellular defects. These results demonstrate that calpains are required for proper assembly and maintenance of integrin attachment complexes. Taken together our data provide in vivo evidence that a calpain-based molecular repair mechanism exists for dealing with attachment complex disruption in adult muscle. Since C

  11. Effects of ced-9 dsRNA on Caenorhabditis elegans and Meloidogyne incognita

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    Robert T. Gaeta

    2011-01-01

    Full Text Available Problem Statement: In metazoans Programmed Cell Death (PCD is essential for proper development. Suppression of PCD is needed to guarantee cell survival and in the nematode Caenorhabditis elegans the regulation of PCD is accomplished by the function of the ced-9 gene. Approach: In this work the use of double stranded RNA (dsRNA to knock-down ced-9 gene function was tested as means to induce PCD. Results: Our results indicate that dsRNA targeting the cell death protection gene ced-9 is effective at decreasing the fecundity of C. elegans by up to 21%. The decreased fecundity correlated with an increased presence of cell corpses in developing embryos. Endogenous ced-9 transcript levels were reduced in progeny of ced-3 mutant nematodes fed bacteria expressing ced-9 dsRNA. These data suggest that nematode fecundity can be reduced by ingestion and exposure to dsRNAs targeting regulation of the cell death pathway. In an attempt to determine if plant parasitic nematodes are susceptible to the targeting of the PCD regulatory pathway we exposed Meloidogyne incognita, a plant parasitic nematode, to ced-9 dsRNA; here we show that this exposure results in decreased gall formation in the tobacco plants. Conclusion/Recommendations: Our results provide the first steps toward using RNAi technologies to attempt nematode control by targeting cell death pathways. Ongoing research with transgenic plants designed to express dsRNA for ced-9-like sequences will further test the feasibility of generating plants with RNAi-based resistance to parasitic nematodes.

  12. An HMG1-like protein facilitates Wnt signaling in Caenorhabditis elegans

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    Jiang, Lily I.; Sternberg, Paul W.

    1999-01-01

    We show that during Caenorhabditis elegans male spicule development, the specification of a glial versus neuronal cell fate in a canonical neurogenic sublineage is dependent on Wnt signaling. Inactivation of a Wnt signaling pathway mediated by the Wnt receptor LIN-17 transforms the SPD sheath cell into its sister, the SPD neuron. We discovered a new mutant, son-1, that displays this same cell fate transformation. The son-1 mutation enhances the phenotypes of reduction-of-function lin-17 mutants in several developmental processes, including vulva development, somatic gonad development, and male tail patterning. son-1 encodes an HMG1/2-like DNA-binding protein and is localized in all cell nuclei through development as revealed by a GFP reporter construct. Disruption of son-1 function by RNA-mediated interference results in the same spicule defect as caused by overexpression of POP-1, a TCF/LEF class HMG protein known to act downstream of the Wnt signaling pathway. Our results provide in vivo evidence for the functional involvement of an HMG1/2-like protein, SON-1, in Wnt signaling. The sequence nonspecific HMG protein SON-1 and the sequence specific HMG protein POP-1 might both act in the Wnt responding cells to regulate gene transcription in opposite directions. PMID:10197987

  13. Evolutionary innovation of the excretory system in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Xiaodong; Chamberlin, Helen M

    2004-03-01

    The evolution of complexity relies on changes that result in new gene functions. Here we show that the unique morphological and functional features of the excretory duct cell in C. elegans result from the gain of expression of a single gene. Our results show that innovation can be achieved by altered expression of a transcription factor without coevolution of all target genes.

  14. Cell fate determination in the Caenorhabditis elegans epidermal lineages

    NARCIS (Netherlands)

    Soete, G.A.J.

    2007-01-01

    The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly compl

  15. Kinesin-1 Acts with Netrin and DCC to Maintain Sensory Neuron Position in Caenorhabditis elegans

    Science.gov (United States)

    Barsi-Rhyne, Benjamin J.; Miller, Kristine M.; Vargas, Christopher T.; Thomas, Anthony B.; Park, Joori; Bremer, Martina; Jarecki, Jessica L.; VanHoven, Miri K.

    2013-01-01

    The organization of neurons and the maintenance of that arrangement are critical to brain function. Failure of these processes in humans can lead to severe birth defects, mental retardation, and epilepsy. Several kinesins have been shown to play important roles in cell migration in vertebrate systems, but few upstream and downstream pathway members have been identified. Here, we utilize the genetic model organism Caenorhabditis elegans to elucidate the pathway by which the C. elegans Kinesin-1 Heavy Chain (KHC)/KIF5 ortholog UNC-116 functions to maintain neuronal cell body position in the PHB sensory neurons. We find that UNC-116/KHC acts in part with the cell and axon migration molecules UNC-6/Netrin and UNC-40/DCC in this process, but in parallel to SAX-3/Robo. We have also identified several potential adaptor, cargo, and regulatory proteins that may provide insight into the mechanism of UNC-116/KHC’s function in this process. These include the cargo receptor UNC-33/CRMP2, the cargo adaptor protein UNC-76/FEZ and its regulator UNC-51/ULK, the cargo molecule UNC-69/SCOCO, and the actin regulators UNC-44/Ankyrin and UNC-34/Enabled. These genes also act in cell migration and axon outgrowth; however, many proteins that function in these processes do not affect PHB position. Our findings suggest an active posterior cell migration mediated by UNC-116/KHC occurs throughout development to maintain proper PHB cell body position and define a new pathway that mediates maintenance of neuronal cell body position. PMID:23475988

  16. QuantWorm: a comprehensive software package for Caenorhabditis elegans phenotypic assays.

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    Sang-Kyu Jung

    Full Text Available Phenotypic assays are crucial in genetics; however, traditional methods that rely on human observation are unsuitable for quantitative, large-scale experiments. Furthermore, there is an increasing need for comprehensive analyses of multiple phenotypes to provide multidimensional information. Here we developed an automated, high-throughput computer imaging system for quantifying multiple Caenorhabditis elegans phenotypes. Our imaging system is composed of a microscope equipped with a digital camera and a motorized stage connected to a computer running the QuantWorm software package. Currently, the software package contains one data acquisition module and four image analysis programs: WormLifespan, WormLocomotion, WormLength, and WormEgg. The data acquisition module collects images and videos. The WormLifespan software counts the number of moving worms by using two time-lapse images; the WormLocomotion software computes the velocity of moving worms; the WormLength software measures worm body size; and the WormEgg software counts the number of eggs. To evaluate the performance of our software, we compared the results of our software with manual measurements. We then demonstrated the application of the QuantWorm software in a drug assay and a genetic assay. Overall, the QuantWorm software provided accurate measurements at a high speed. Software source code, executable programs, and sample images are available at www.quantworm.org. Our software package has several advantages over current imaging systems for C. elegans. It is an all-in-one package for quantifying multiple phenotypes. The QuantWorm software is written in Java and its source code is freely available, so it does not require use of commercial software or libraries. It can be run on multiple platforms and easily customized to cope with new methods and requirements.

  17. Deletion of the mitochondrial superoxide dismutase sod-2 extends lifespan in Caenorhabditis elegans.

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    Jeremy M Van Raamsdonk

    2009-02-01

    Full Text Available The oxidative stress theory of aging postulates that aging results from the accumulation of molecular damage caused by reactive oxygen species (ROS generated during normal metabolism. Superoxide dismutases (SODs counteract this process by detoxifying superoxide. It has previously been shown that elimination of either cytoplasmic or mitochondrial SOD in yeast, flies, and mice results in decreased lifespan. In this experiment, we examine the effect of eliminating each of the five individual sod genes present in Caenorhabditis elegans. In contrast to what is observed in other model organisms, none of the sod deletion mutants shows decreased lifespan compared to wild-type worms, despite a clear increase in sensitivity to paraquat- and juglone-induced oxidative stress. In fact, even mutants lacking combinations of two or three sod genes survive at least as long as wild-type worms. Examination of gene expression in these mutants reveals mild compensatory up-regulation of other sod genes. Interestingly, we find that sod-2 mutants are long-lived despite a significant increase in oxidatively damaged proteins. Testing the effect of sod-2 deletion on known pathways of lifespan extension reveals a clear interaction with genes that affect mitochondrial function: sod-2 deletion markedly increases lifespan in clk-1 worms while clearly decreasing the lifespan of isp-1 worms. Combined with the mitochondrial localization of SOD-2 and the fact that sod-2 mutant worms exhibit phenotypes that are characteristic of long-lived mitochondrial mutants-including slow development, low brood size, and slow defecation-this suggests that deletion of sod-2 extends lifespan through a similar mechanism. This conclusion is supported by our demonstration of decreased oxygen consumption in sod-2 mutant worms. Overall, we show that increased oxidative stress caused by deletion of sod genes does not result in decreased lifespan in C. elegans and that deletion of sod-2 extends worm

  18. RNAi Screen Identifies Novel Regulators of RNP Granules in the Caenorhabditis elegans Germ Line

    Science.gov (United States)

    Wood, Megan P.; Hollis, Angela; Severance, Ashley L.; Karrick, Megan L.; Schisa, Jennifer A.

    2016-01-01

    Complexes of RNA and RNA binding proteins form large-scale supramolecular structures under many cellular contexts. In Caenorhabditis elegans, small germ granules are present in the germ line that share characteristics with liquid droplets that undergo phase transitions. In meiotically-arrested oocytes of middle-aged hermaphrodites, the germ granules appear to aggregate or condense into large assemblies of RNA-binding proteins and maternal mRNAs. Prior characterization of the assembly of large-scale RNP structures via candidate approaches has identified a small number of regulators of phase transitions in the C. elegans germ line; however, the assembly, function, and regulation of these large RNP assemblies remain incompletely understood. To identify genes that promote remodeling and assembly of large RNP granules in meiotically-arrested oocytes, we performed a targeted, functional RNAi screen and identified over 300 genes that regulate the assembly of the RNA-binding protein MEX-3 into large granules. Among the most common GO classes are several categories related to RNA biology, as well as novel categories such as cell cortex, ER, and chromosome segregation. We found that arrested oocytes that fail to localize MEX-3 into cortical granules display reduced oocyte quality, consistent with the idea that the larger RNP assemblies promote oocyte quality when fertilization is delayed. Interestingly, a relatively small number of genes overlap with the regulators of germ granule assembly during normal development, or with the regulators of solid RNP granules in cgh-1 oocytes, suggesting fundamental differences in the regulation of RNP granule phase transitions during meiotic arrest. PMID:27317775

  19. Sensitive and precise quantification of insulin-like mRNA expression in Caenorhabditis elegans.

    Science.gov (United States)

    Baugh, L Ryan; Kurhanewicz, Nicole; Sternberg, Paul W

    2011-03-22

    Insulin-like signaling regulates developmental arrest, stress resistance and lifespan in the nematode Caenorhabditis elegans. However, the genome encodes 40 insulin-like peptides, and the regulation and function of individual peptides is largely uncharacterized. We used the nCounter platform to measure mRNA expression of all 40 insulin-like peptides as well as the insulin-like receptor daf-2, its transcriptional effector daf-16, and the daf-16 target gene sod-3. We validated the platform using 53 RNA samples previously characterized by high density oligonucleotide microarray analysis. For this set of genes and the standard nCounter protocol, sensitivity and precision were comparable between the two platforms. We optimized conditions of the nCounter assay by varying the mass of total RNA used for hybridization, thereby increasing sensitivity up to 50-fold and reducing the median coefficient of variation as much as 4-fold. We used deletion mutants to demonstrate specificity of the assay, and we used optimized conditions to assay insulin-like gene expression throughout the C. elegans life cycle. We detected expression for nearly all insulin-like genes and find that they are expressed in a variety of distinct patterns suggesting complexity of regulation and specificity of function. We identified insulin-like genes that are specifically expressed during developmental arrest, larval development, adulthood and embryogenesis. These results demonstrate that the nCounter platform provides a powerful approach to analyzing insulin-like gene expression dynamics, and they suggest hypotheses about the function of individual insulin-like genes.

  20. Sensitive and precise quantification of insulin-like mRNA expression in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    L Ryan Baugh

    Full Text Available Insulin-like signaling regulates developmental arrest, stress resistance and lifespan in the nematode Caenorhabditis elegans. However, the genome encodes 40 insulin-like peptides, and the regulation and function of individual peptides is largely uncharacterized. We used the nCounter platform to measure mRNA expression of all 40 insulin-like peptides as well as the insulin-like receptor daf-2, its transcriptional effector daf-16, and the daf-16 target gene sod-3. We validated the platform using 53 RNA samples previously characterized by high density oligonucleotide microarray analysis. For this set of genes and the standard nCounter protocol, sensitivity and precision were comparable between the two platforms. We optimized conditions of the nCounter assay by varying the mass of total RNA used for hybridization, thereby increasing sensitivity up to 50-fold and reducing the median coefficient of variation as much as 4-fold. We used deletion mutants to demonstrate specificity of the assay, and we used optimized conditions to assay insulin-like gene expression throughout the C. elegans life cycle. We detected expression for nearly all insulin-like genes and find that they are expressed in a variety of distinct patterns suggesting complexity of regulation and specificity of function. We identified insulin-like genes that are specifically expressed during developmental arrest, larval development, adulthood and embryogenesis. These results demonstrate that the nCounter platform provides a powerful approach to analyzing insulin-like gene expression dynamics, and they suggest hypotheses about the function of individual insulin-like genes.

  1. Acyl-CoA oxidase complexes control the chemical message produced by Caenorhabditis elegans.

    Science.gov (United States)

    Zhang, Xinxing; Feng, Likui; Chinta, Satya; Singh, Prashant; Wang, Yuting; Nunnery, Joshawna K; Butcher, Rebecca A

    2015-03-31

    Caenorhabditis elegans uses ascaroside pheromones to induce development of the stress-resistant dauer larval stage and to coordinate various behaviors. Peroxisomal β-oxidation cycles are required for the biosynthesis of the fatty acid-derived side chains of the ascarosides. Here we show that three acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, form different protein homo- and heterodimers with distinct substrate preferences. Mutations in the acyl-CoA oxidase genes acox-1, -2, and -3 led to specific defects in ascaroside production. When the acyl-CoA oxidases were expressed alone or in pairs and purified, the resulting acyl-CoA oxidase homo- and heterodimers displayed different side-chain length preferences in an in vitro activity assay. Specifically, an ACOX-1 homodimer controls the production of ascarosides with side chains with nine or fewer carbons, an ACOX-1/ACOX-3 heterodimer controls the production of those with side chains with seven or fewer carbons, and an ACOX-2 homodimer controls the production of those with ω-side chains with less than five carbons. Our results support a biosynthetic model in which β-oxidation enzymes act directly on the CoA-thioesters of ascaroside biosynthetic precursors. Furthermore, we identify environmental conditions, including high temperature and low food availability, that induce the expression of acox-2 and/or acox-3 and lead to corresponding changes in ascaroside production. Thus, our work uncovers an important mechanism by which C. elegans increases the production of the most potent dauer pheromones, those with the shortest side chains, under specific environmental conditions.

  2. Administration with Bushenkangshuai Tang alleviates UV irradiation- and oxidative stress-induced lifespan defects in nematode Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

    Qi RUI; Qin LU; Dayong WANG

    2009-01-01

    During normal metabolism, oxidative bypro-ducts will inevitably generate and damage molecules thereby impairing their biological functions, including the is a traditional Chinese medicine widely used for clini-cally treating premature ovarian failure. In the present study, BT administration at high concentrations signifi-cantly increased lifespan, slowed aging-related decline, and delayed accumulation of aging-related cellular damage in wild-type Caenorhabditis elegans. BT admin-istration could further largely alleviate the aging defects induced by UV and oxidative stresses, and BT administra-tion at different concentrations could largely rescue the aging defects in mev-1 mutant animals. The protective effects of BT administration on aging process were at least partially dependent on the Ins/IGF-like signaling pathway. Moreover, BT administration at different concentrations obviously altered the expression patterns of antioxidant genes and suppressed the severe stress responses induced by UV and oxidative stresses, suggesting that BT-induced tolerance to UV or oxidative stress might result from reactive oxygen species scavenging. BT administration during development was not necessarily a requirement for UV and oxidative stress resistance, and the concentrations of administrated BT examined were not toxic for nematodes. Therefore, BT administration could effectively retrieve the aging defects induced by UV irradiation and oxidative stress in Caenorhabditis elegans.

  3. Caenorhabditis elegans battling starvation stress: low levels of ethanol prolong lifespan in L1 larvae.

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    Paola V Castro

    Full Text Available The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%; higher concentrations to 68 mM (0.4% did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response.

  4. Toxicity evaluation of prodigiosin from Serratia marcescens in a Caenorhabditis elegans model

    Science.gov (United States)

    Seah, Siew-Wei; Nathan, Sheila; Wan, Kiew-Lian

    2016-11-01

    Serratia marcescens produces several secondary metabolites, including a red antimicrobial pigment, prodigiosin. There is considerable interest in prodigiosin and its derivatives due to their anticancer and immunosuppressive properties. Prodigiosin has also become the main choice of red dye in textiles. As prodigiosin has potentially high commercial value, there is a demand to develop high-throughput and cost-effective bioprocesses for prodigiosin production. However little is still known about its toxicity. This study was carried out to investigate the toxicity effect of prodigiosin. To determine if prodigiosin was potentially toxic to eukaryotic systems, the S. marcescens ATCC 274 wild type (Sma 274) and the non-prodigiosin producer S. marcescens Bizio WF mutant ATCC 29635 (WF mutant) were grown under the optimised conditions for prodigiosin production and fed to the nematode Caenorhabditis elegans. The mean time to death (TDmean) for Sma 274-infected worms assayed on agar was 112.6 hours while the WF mutant culture had a TDmean of 104.4 hours. However, the nematode killing kinetics were not significantly different between the prodigiosin-producing and non-producing S. marcescens strains (p>0.05). In lieu of its non-toxic property, prodigiosin has the potential to be developed for safe therapeutic applications and as a safe environmental friendly bio-dye.

  5. Mitochondrial superoxide increase is essential for Caenorhabditis elegans against Enterococcus faecalis infection

    Directory of Open Access Journals (Sweden)

    N Feng1

    2015-12-01

    Full Text Available Enterococcus faecalis infection can cause serious diseases including cancer development. Recently it has been reported that mitochondrial reactive oxygen species (mROS are required for host immune defenses against bacteria and many mutations in mitochondrial electron transport chain (mETC genes have an effect on mROS production. To identify the exact role of mROS during E. faecalis infection, we thus decide to knockdown the expression of mev-1 and isp-1 in Caenorhabditis elegans using RNAi. The knockdown of mev-1 and isp-1 causes increased susceptibility and increased resistance to E. faecalis infection, respectively. The mev-1(RNAi can also down-regulate antimicrobial genes (C17H12.8, mtl-1 and bli-3, whereas these antimicrobial genes are up-regulated in isp-1(RNAi animals after bacterial infection. Further, significant increase of mitochondrial superoxide and mitochondrial sod expressions have been observed in isp-1(RNAi animals. Conversely, the mev-1(RNAi worms show a decrease of mitochondrial superoxide and mitochondrial sod expressions. Prooxidant paraquat, which is a mitochondrial superoxide generator, can increase survival rate of mev-1(RNAi animals after E. faecalis infection. All together, the enhancement of mitochondrial superoxide contributes to anti-bacterial immunity and a better knowledge of them should open new avenues for preventive strategies against bacterial infection and also limiting the development of infection-associated cancer.

  6. Effects of developmental stage, salts, and food presence on aquatic toxicological endpoints using Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Donkin, S.G.; Williams, P.L. [Univ. of Georgia, Athens, GA (United States). Environmental Health Science

    1995-12-31

    The objective of this study was to standardize the testing protocol for aquatic toxicity tests with the nematode Caenorhabditis elegans. Several variables which may be important in determining the test outcome were investigated in a randomized block design. Concentration-response data were obtained on nematodes of various developmental stages exposed to four metals (Cd, Pb, Cu, and Hg) and a water-soluble organic toxicant, sodium Pentachlorophenate (PCP), under conditions of varied solvent medium (with or without salts and with or without a bacterial food source). The endpoints measured were 24 and 96-h mortality, as well as development of larval stages to adulthood and evidence of reproduction. The results suggest that nematodes of various ages respond similarly to a given toxicant for all endpoints measured, although adults cultured from eggs appeared more sensitive than adults cultured from dauer larvae. The most important environmental variable in determining toxicity was the medium in which the tests were conducted. The presence of potassium and sodium salts in the medium significantly (p<0.05) reduced the toxicity of many test samples. The presence of bacteria had little effect on 24-h tests with salts, but was important in 96-h survival and development. Based on sensitivity and ease of handling, adults cultured from eggs are recommended in both 24-h and 96-h mortality (LC50 value) tests, as well as 96-h reproduction tests.

  7. Small RNA in situ hybridization in Caenorhabditis elegans, combined with RNA-seq, identifies germline-enriched microRNAs.

    Science.gov (United States)

    McEwen, Tamara J; Yao, Qiuming; Yun, Sijung; Lee, Chin-Yung; Bennett, Karen L

    2016-10-15

    Over four hundred different microRNAs (miRNAs) have been identified in the genome of the model organism the nematode Caenorhabditis elegans. As the germline is dedicated to the preservation of each species, and almost half of all the cells in an adult nematode are germline, it is likely that regulatory miRNAs are important for germline development and maintenance. In C. elegans the miR35 family has strong maternal effects, contributing to normal embryogenesis and to adult fecundity. To determine whether any particular miRNAs are greatly enriched in the C. elegans germline we used RNA-seq to compare the miRNA populations in several germline-defective strains of adult C. elegans worms, including glp-4(germline proliferation-4), glh-1(germline helicase-1) and dcr-1(dicer-1). Statistical analyses of RNA-seq comparisons identified 13 miRNAs that are germline-enriched, including seven members of the well-studied miR35 family that were reduced as much as 1000-fold in TaqMan qRT PCR miRNA assays. Along with the miR35s, six others: miR-56 (a member of the miR51 family),-70, -244, -260 , -788 and -4813, none of which previously considered as such, were also identified by RNA-seq as germline-enriched candidates. We went on to develop a successful miRNA in situ hybridization protocol for C. elegans, revealing miR35s specifically concentrate during oogenesis in the pachytene region of the gonad, and persist throughout early embryogenesis, while in adult animals neither let-7 nor miR-228 has a germline-bias.

  8. The phytochemical glaucarubinone promotes mitochondrial metabolism, reduces body fat, and extends lifespan of Caenorhabditis elegans.

    Science.gov (United States)

    Zarse, K; Bossecker, A; Müller-Kuhrt, L; Siems, K; Hernandez, M A; Berendsohn, W G; Birringer, M; Ristow, M

    2011-04-01

    Naturally occurring compounds that promote energy expenditure and delay aging in model organisms may be of significant interest, since these substances potentially provide pharmaceutical approaches to tackle obesity and promote healthy lifespan in humans. We aimed to test whether pharmaceutical concentrations of glaucarubinone, a cytotoxic and antimalarial quassinoid known from different species of the plant family Simaroubaceae, are capable of affecting metabolism and/or extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Adult C. elegans roundworms, maintained on agar plates, were fed with E. coli strain OP50 bacteria, and glaucarubinone was applied to the agar to test (i) whether it alters respiration rates and mitochondrial activity, (ii) whether it affects body fat content, and (iii) whether it may promote longevity by quantifying survival in the presence and absence of the compound. We have found that glaucarubinone induces oxygen consumption and reduces body fat content of C. elegans. Moreover and consistent with the concept of mitohormesis, glaucarubinone extends C. elegans lifespan when applied at a concentration of 1 or 10 nanomolar. Taken together, glaucarubinone is capable of reducing body fat and promoting longevity in C. elegans, tentatively suggesting that this compound may promote metabolic health and lifespan in mammals and possibly humans.

  9. Lactobacillus salivarius strain FDB89 induced longevity in Caenorhabditis elegans by dietary restriction.

    Science.gov (United States)

    Zhao, Yang; Zhao, Liang; Zheng, Xiaonan; Fu, Tianjiao; Guo, Huiyuan; Ren, Fazheng

    2013-04-01

    In this study, we utilized the nematode Caenorhabditis elegans to assess potential life-expanding effect of Lactobacillus salivarius strain FDB89 (FDB89) isolated from feces of centenarians in Bama County (Guangxi, China). This study showed that feeding FDB89 extended the mean life span in C. elegans by up to 11.9% compared to that of control nematodes. The reduced reproductive capacities, pharyngeal pumping rate, growth, and increased superoxide dismutase (SOD) activity and XTT reduction capacity were also observed in FDB89 feeding worms. To probe the anti-aging mechanism further, we incorporated a food gradient feeding assay and assayed the life span of eat-2 mutant. The results demonstrated that the maximal life span of C. elegans fed on FDB89 was achieved at the concentration of 1.0 mg bacterial cells/plate, which was 10-fold greater than that of C. elegans fed on E. coli OP50 (0.1 mg bacterial cells/plate). However, feeding FDB89 could not further extend the life span of eat-2 mutant. These results indicated that FDB89 modulated the longevity of C. elegans in a dietary restriction-dependent manner and expanded the understanding of anti-aging effect of probiotics.

  10. The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety

    Science.gov (United States)

    Juozaityte, Vaida; Pladevall-Morera, David; Podolska, Agnieszka; Nørgaard, Steffen; Pocock, Roger

    2017-01-01

    Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans. Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show that ETS-5 acts to promote roaming and inhibit quiescence by setting the internal “satiety quotient” through fat regulation. Acting from the ASG and BAG sensory neurons, we show that ETS-5 functions in a complex network with serotonergic and neuropeptide signaling pathways to control food-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms. PMID:28193866

  11. Effects of Microcystin-LR Exposure on Spermiogenesis in Nematode Caenorhabditis elegans.

    Science.gov (United States)

    Li, Yunhui; Zhang, Minhui; Chen, Pan; Liu, Ran; Liang, Geyu; Yin, Lihong; Pu, Yuepu

    2015-09-22

    Little is known about the effect on spermiogenesis induced by microcystin-leucine arginine (MC-LR), even though such data are very important to better elucidate reproductive health. In the current work, with the aid of nematode Caenorhabditis elegans (C. elegans) as an animal model, we investigated the defects on spermiogenesis induced by MC-LR. Our results showed that MC-LR exposure induced sperm morphology abnormality and caused severe defects of sperm activation, trans-activation, sperm behavior and competition. Additionally, the expression levels of spe-15 were significantly decreased in C. elegans exposed to MC-LR lower than 16.0 μg/L, while the expression levels of spe-10 and fer-1 could be significantly lowered in C. elegans even exposed to 1.0 μg/L of MC-LR. Therefore, the present study reveals that MC-LR can induce adverse effects on spermiogenesis, and those defects of sperm functions may be induced by the decreases of spe-10, spe-15 and fer-1 gene expressions in C. elegans.

  12. A conserved upstream motif orchestrates autonomous, germline-enriched expression of Caenorhabditis elegans piRNAs.

    Directory of Open Access Journals (Sweden)

    Allison C Billi

    Full Text Available Piwi-interacting RNAs (piRNAs fulfill a critical, conserved role in defending the genome against foreign genetic elements. In many organisms, piRNAs appear to be derived from processing of a long, polycistronic RNA precursor. Here, we establish that each Caenorhabditis elegans piRNA represents a tiny, autonomous transcriptional unit. Remarkably, the minimal C. elegans piRNA cassette requires only a 21 nucleotide (nt piRNA sequence and an ∼50 nt upstream motif with limited genomic context for expression. Combining computational analyses with a novel, in vivo transgenic system, we demonstrate that this upstream motif is necessary for independent expression of a germline-enriched, Piwi-dependent piRNA. We further show that a single nucleotide position within this motif directs differential germline enrichment. Accordingly, over 70% of C. elegans piRNAs are selectively expressed in male or female germline, and comparison of the genes they target suggests that these two populations have evolved independently. Together, our results indicate that C. elegans piRNA upstream motifs act as independent promoters to specify which sequences are expressed as piRNAs, how abundantly they are expressed, and in what germline. As the genome encodes well over 15,000 unique piRNA sequences, our study reveals that the number of transcriptional units encoding piRNAs rivals the number of mRNA coding genes in the C. elegans genome.

  13. A screening-based platform for the assessment of cellular respiration in Caenorhabditis elegans.

    Science.gov (United States)

    Koopman, Mandy; Michels, Helen; Dancy, Beverley M; Kamble, Rashmi; Mouchiroud, Laurent; Auwerx, Johan; Nollen, Ellen A A; Houtkooper, Riekelt H

    2016-10-01

    Mitochondrial dysfunction is at the core of many diseases ranging from inherited metabolic diseases to common conditions that are associated with aging. Although associations between aging and mitochondrial function have been identified using mammalian models, much of the mechanistic insight has emerged from Caenorhabditis elegans. Mitochondrial respiration is recognized as an indicator of mitochondrial health. The Seahorse XF96 respirometer represents the state-of-the-art platform for assessing respiration in cells, and we adapted the technique for applications involving C. elegans. Here we provide a detailed protocol to optimize and measure respiration in C. elegans with the XF96 respirometer, including the interpretation of parameters and results. The protocol takes ∼2 d to complete, excluding the time spent culturing C. elegans, and it includes (i) the preparation of C. elegans samples, (ii) selection and loading of compounds to be injected, (iii) preparation and execution of a run with the XF96 respirometer and (iv) postexperimental data analysis, including normalization. In addition, we compare our XF96 application with other existing techniques, including the eight-well Seahorse XFp. The main benefits of the XF96 include the limited number of worms required and the high throughput capacity due to the 96-well format.

  14. A new role for laminins as modulators of protein toxicity in Caenorhabditis elegans.

    Science.gov (United States)

    Jensen, Louise T; Møller, Tine H; Larsen, Simon A; Jakobsen, Helle; Olsen, Anders

    2012-02-01

    Protein misfolding is a common theme in aging and several age-related diseases such as Alzheimer's and Parkinson's disease. The processes involved in the development of these diseases are many and complex. Here, we show that components of the basement membrane (BM), particularly laminin, affect protein integrity of the muscle cells they support. We knocked down gene expression of epi-1, a laminin α-chain, and found that this resulted in increased proteotoxicity in different Caenorhabditis elegans transgenic models, expressing aggregating proteins in the body wall muscle. The effect could partially be rescued by decreased insulin-like signaling, known to slow the aging process and the onset of various age-related diseases. Our data points to an underlying molecular mechanism involving proteasomal degradation and HSP-16 chaperone activity. Furthermore, epi-1-depleted animals had altered synaptic function and displayed hypersensitivity to both levamisole and aldicarb, an acetylcholine receptor agonist and an acetylcholinesterase inhibitor, respectively. Our results implicate the BM as an extracellular modulator of protein homeostasis in the adjacent muscle cells. This is in agreement with previous research showing that imbalance in neuromuscular signaling disturbs protein homeostasis in the postsynaptic cell. In our study, proteotoxicity may indeed be mediated by the neuromuscular junction which is part of the BM, where laminins are present in high concentration, ensuring the proper microenvironment for neuromuscular signaling. Laminins are evolutionarily conserved, and thus the BM may play a much more causal role in protein misfolding diseases than currently recognized.

  15. Molecular strategies of the Caenorhabditis elegans dauer larva to survive extreme desiccation.

    Science.gov (United States)

    Erkut, Cihan; Vasilj, Andrej; Boland, Sebastian; Habermann, Bianca; Shevchenko, Andrej; Kurzchalia, Teymuras V

    2013-01-01

    Massive water loss is a serious challenge for terrestrial animals, which usually has fatal consequences. However, some organisms have developed means to survive this stress by entering an ametabolic state called anhydrobiosis. The molecular and cellular mechanisms underlying this phenomenon are poorly understood. We recently showed that Caenorhabditis elegans dauer larva, an arrested stage specialized for survival in adverse conditions, is resistant to severe desiccation. However, this requires a preconditioning step at a mild desiccative environment to prepare the organism for harsher desiccation conditions. A systems approach was used to identify factors that are activated during this preconditioning. Using microarray analysis, proteomics, and bioinformatics, genes, proteins, and biochemical pathways that are upregulated during this process were identified. These pathways were validated via reverse genetics by testing the desiccation tolerances of mutants. These data show that the desiccation response is activated by hygrosensation (sensing the desiccative environment) via head neurons. This leads to elimination of reactive oxygen species and xenobiotics, expression of heat shock and intrinsically disordered proteins, polyamine utilization, and induction of fatty acid desaturation pathway. Remarkably, this response is specific and involves a small number of functional pathways, which represent the generic toolkit for anhydrobiosis in plants and animals.

  16. A fluorogenic aryl fluorosulfate for intraorganellar transthyretin imaging in living cells and in Caenorhabditis elegans.

    Science.gov (United States)

    Baranczak, Aleksandra; Liu, Yu; Connelly, Stephen; Du, Wen-Ge Han; Greiner, Erin R; Genereux, Joseph C; Wiseman, R Luke; Eisele, Yvonne S; Bradbury, Nadine C; Dong, Jiajia; Noodleman, Louis; Sharpless, K Barry; Wilson, Ian A; Encalada, Sandra E; Kelly, Jeffery W

    2015-06-17

    Fluorogenic probes, due to their often greater spatial and temporal sensitivity in comparison to permanently fluorescent small molecules, represent powerful tools to study protein localization and function in the context of living systems. Herein, we report fluorogenic probe 4, a 1,3,4-oxadiazole designed to bind selectively to transthyretin (TTR). Probe 4 comprises a fluorosulfate group not previously used in an environment-sensitive fluorophore. The fluorosulfate functional group does not react covalently with TTR on the time scale required for cellular imaging, but does red shift the emission maximum of probe 4 in comparison to its nonfluorosulfated analogue. We demonstrate that probe 4 is dark in aqueous buffers, whereas the TTR·4 complex exhibits a fluorescence emission maximum at 481 nm. The addition of probe 4 to living HEK293T cells allows efficient binding to and imaging of exogenous TTR within intracellular organelles, including the mitochondria and the endoplasmic reticulum. Furthermore, live Caenorhabditis elegans expressing human TTR transgenically and treated with probe 4 display TTR·4 fluorescence in macrophage-like coelomocytes. An analogue of fluorosulfate probe 4 does react selectively with TTR without labeling the remainder of the cellular proteome. Studies on this analogue suggest that certain aryl fluorosulfates, due to their cell and organelle permeability and activatable reactivity, could be considered for the development of protein-selective covalent probes.

  17. Automatic segmentation and 3D feature extraction of protein aggregates in Caenorhabditis elegans

    Science.gov (United States)

    Rodrigues, Pedro L.; Moreira, António H. J.; Teixeira-Castro, Andreia; Oliveira, João; Dias, Nuno; Rodrigues, Nuno F.; Vilaça, João L.

    2012-03-01

    In the last years, it has become increasingly clear that neurodegenerative diseases involve protein aggregation, a process often used as disease progression readout and to develop therapeutic strategies. This work presents an image processing tool to automatic segment, classify and quantify these aggregates and the whole 3D body of the nematode Caenorhabditis Elegans. A total of 150 data set images, containing different slices, were captured with a confocal microscope from animals of distinct genetic conditions. Because of the animals' transparency, most of the slices pixels appeared dark, hampering their body volume direct reconstruction. Therefore, for each data set, all slices were stacked in one single 2D image in order to determine a volume approximation. The gradient of this image was input to an anisotropic diffusion algorithm that uses the Tukey's biweight as edge-stopping function. The image histogram median of this outcome was used to dynamically determine a thresholding level, which allows the determination of a smoothed exterior contour of the worm and the medial axis of the worm body from thinning its skeleton. Based on this exterior contour diameter and the medial animal axis, random 3D points were then calculated to produce a volume mesh approximation. The protein aggregations were subsequently segmented based on an iso-value and blended with the resulting volume mesh. The results obtained were consistent with qualitative observations in literature, allowing non-biased, reliable and high throughput protein aggregates quantification. This may lead to a significant improvement on neurodegenerative diseases treatment planning and interventions prevention.

  18. Behavioral analysis of the huntingtin-associated protein 1 ortholog trak-1 in Caenorhabditis elegans.

    Science.gov (United States)

    Norflus, Fran; Bu, Jingnan; Guyton, Evon; Gutekunst, Claire-Anne

    2016-09-01

    The precise role of huntingtin-associated protein 1 (HAP1) is not known, but studies have shown that it is important for early development and survival. A Caenorhabditis elegans ortholog of HAP1, T27A3.1 (also called trak-1), has been found and is expressed in a subset of neurons. Potential behavioral functions of three knockout lines of T27A3.1 were examined. From its suspected role in mice we hypothesize that T27A3.1 might be involved in egg hatching and early growth, mechanosensation, chemosensation, sensitivity to osmolarity, and synaptic transmission. Our studies show that the knockout worms are significantly different from the wild-type (WT) worms only in the synaptic transmission test, which was measured by adding aldicarb, an acetylcholinesterase inhibitor. The change in function was determined by measuring the number of worms paralyzed. However, when the T27A3.1 worms were tested for egg hatching and early growth, mechanosensation, chemosensation, and sensitivity to osmolarity, there were no significant differences between the knockout and WT worms. © 2016 Wiley Periodicals, Inc.

  19. Bayesian Inference of Forces Causing Cytoplasmic Streaming in Caenorhabditis elegans Embryos and Mouse Oocytes.

    Science.gov (United States)

    Niwayama, Ritsuya; Nagao, Hiromichi; Kitajima, Tomoya S; Hufnagel, Lars; Shinohara, Kyosuke; Higuchi, Tomoyuki; Ishikawa, Takuji; Kimura, Akatsuki

    2016-01-01

    Cellular structures are hydrodynamically interconnected, such that force generation in one location can move distal structures. One example of this phenomenon is cytoplasmic streaming, whereby active forces at the cell cortex induce streaming of the entire cytoplasm. However, it is not known how the spatial distribution and magnitude of these forces move distant objects within the cell. To address this issue, we developed a computational method that used cytoplasm hydrodynamics to infer the spatial distribution of shear stress at the cell cortex induced by active force generators from experimentally obtained flow field of cytoplasmic streaming. By applying this method, we determined the shear-stress distribution that quantitatively reproduces in vivo flow fields in Caenorhabditis elegans embryos and mouse oocytes during meiosis II. Shear stress in mouse oocytes were predicted to localize to a narrower cortical region than that with a high cortical flow velocity and corresponded with the localization of the cortical actin cap. The predicted patterns of pressure gradient in both species were consistent with species-specific cytoplasmic streaming functions. The shear-stress distribution inferred by our method can contribute to the characterization of active force generation driving biological streaming.

  20. The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity.

    Science.gov (United States)

    Sundaram, Meera V; Buechner, Matthew

    2016-05-01

    The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal's life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes.

  1. Dissection of neuronal gap junction circuits that regulate social behavior in Caenorhabditis elegans

    Science.gov (United States)

    Jang, Heeun; Levy, Sagi; Flavell, Steven W.; Mende, Fanny; Latham, Richard; Zimmer, Manuel; Bargmann, Cornelia I.

    2017-01-01

    A hub-and-spoke circuit of neurons connected by gap junctions controls aggregation behavior and related behavioral responses to oxygen, pheromones, and food in Caenorhabditis elegans. The molecular composition of the gap junctions connecting RMG hub neurons with sensory spoke neurons is unknown. We show here that the innexin gene unc-9 is required in RMG hub neurons to drive aggregation and related behaviors, indicating that UNC-9–containing gap junctions mediate RMG signaling. To dissect the circuit in detail, we developed methods to inhibit unc-9–based gap junctions with dominant-negative unc-1 transgenes. unc-1(dn) alters a stomatin-like protein that regulates unc-9 electrical signaling; its disruptive effects can be rescued by a constitutively active UNC-9::GFP protein, demonstrating specificity. Expression of unc-1(dn) in RMG hub neurons, ADL or ASK pheromone-sensing neurons, or URX oxygen-sensing neurons disrupts specific elements of aggregation-related behaviors. In ADL, unc-1(dn) has effects opposite to those of tetanus toxin light chain, separating the roles of ADL electrical and chemical synapses. These results reveal roles of gap junctions in a complex behavior at cellular resolution and provide a tool for similar exploration of other gap junction circuits. PMID:28143932

  2. On the morphogenesis of glial compartments in the sensory organs of Caenorhabditis elegans.

    Science.gov (United States)

    Oikonomou, Grigorios; Shaham, Shai

    2012-01-01

    Glial cells surround neuronal endings and isolate them within specialized compartments. This architecture is found at synapses in the central nervous system, as well as at receptive endings of sensory neurons. Recent studies are beginning to uncover the contributions of glial compartments to the functions of the ensheathed neurons. However, the cellular and molecular processes that guide compartment morphogenesis remain unknown. The main sensory organ of Caenorhabditis elegans, the amphid, provides an experimentally tractable setting in which to address the mechanisms underlying glial compartment formation. Amphid development is stereotyped and amphid structure is easily assayed. We recently uncovered a molecular tug of war that regulates the size of the amphid sensory compartment. The Nemo-like kinase LIT-1 interacts with the glial cytoskeleton to promote compartment growth, a process that also involves components of the retromer complex, while the Patched-related transmembrane protein DAF-6 keeps this expansion in check. Here we discuss how regulation of secretion by the cytoskeleton could guide the sculpting of glial compartments.

  3. Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans

    Science.gov (United States)

    Nguyen, Jeffrey; Shipley, Frederick; Linder, Ashley; Plummer, George; Liu, Mochi; Setru, Sagar; Shaevitz, Joshua; Leifer, Andrew

    The ability to acquire large-scale recordings of neuronal activity in awake and unrestrained animals is needed to provide new insights into how populations of neurons generate animal behavior. Acquiring this data, however, is challenging because it is difficult to track and image individual neurons as an animal deforms its posture and moves many body lengths. Here, we present an instrument capable of recording intracellular calcium transients from the majority of neurons in the head of a freely behaving Caenorhabditis elegans with cellular resolution while simultaneously recording the animal's position, posture, and locomotion. 3D volumetric fluorescent images of neurons expressing the calcium indicator GCaMP6s are recorded at 6 head-volumes/s using spinning disk confocal microscopy. At the same time, we record low magnification images of the animal to measure the animals behavior and track its head as it moves. We develop a time independent neuronal matching algorithm that uses non-rigid point set registration and machine learning to correctly match neurons across time. Using this method, we are able to observe calcium transients from up to 90 neurons for over 4 min and correlate the neural activity with the animal's behavior.

  4. Extracellular dopamine and alterations on dopamine transporter are related to reserpine toxicity in Caenorhabditis elegans.

    Science.gov (United States)

    Reckziegel, Patrícia; Chen, Pan; Caito, Sam; Gubert, Priscila; Soares, Félix Alexandre Antunes; Fachinetto, Roselei; Aschner, Michael

    2016-03-01

    Reserpine is used as an animal model of parkinsonism. We hypothesized that the involuntary movements induced by reserpine in rodents are induced by dopaminergic toxicity caused by extracellular dopamine accumulation. The present study tested the effects of reserpine on the dopaminergic system in Caenorhabditis elegans. Reserpine was toxic to worms (decreased the survival, food intake, development and changed egg laying and defecation cycles). In addition, reserpine increased the worms' locomotor rate on food and decreased dopamine levels. Morphological evaluations of dopaminergic CEP neurons confirmed neurodegeneration characterized by decreased fluorescence intensity and the number of worms with intact CEP neurons, and increased number of shrunken somas per worm. These effects were unrelated to reserpine's effect on decreased expression of the dopamine transporter, dat-1. Interestingly, the locomotor rate on food and the neurodegenerative parameters fully recovered to basal conditions upon reserpine withdrawal. Furthermore, reserpine decreased survival in vesicular monoamine transporter and dat-1 loss-of-function mutant worms. In addition, worms pre-exposed to dopamine followed by exposure to reserpine had decreased survival. Reserpine activated gst-4, which controls a phase II detoxification enzymes downstream of nuclear factor (erythroid-derived-2)-like 2. Our findings establish that the dopamine transporter, dat-1, plays an important role in reserpine toxicity, likely by increasing extracellular dopamine concentrations.

  5. Centripetal flow of pseudopodial surface components could propel the amoeboid movement of Caenorhabditis elegans spermatozoa.

    Science.gov (United States)

    Roberts, T M; Ward, S

    1982-01-01

    Latex beads and wheat germ agglutinin (WGA) were used to examine the movement of membrane components on amoeboid spermatozoa of Caenorhabditis elegans. The behavior of beads attached to the cell revealed continuous, directed movement from the tip of the pseudopod to its base, but no movement on the cell body. Lectin receptors are also cleared from the pseudopod (4). Blocking preexisting lectin receptors with unlabeled WGA followed by pulse-labeling wih fluorescent WGA showed that new lectin receptors are continuously inserted at the tip of the pseudopod. Like latex beads, these new lectin receptors move continuously over the pseudopod surface to the cell body-pseudopod junction where they are probably internalized. Mutants altering the rate of membrane flow, and eliminating its topographical asymmetry, have been identified. Together with the observation that fluorescent phospholipids are cleared from the pseudopod of developing spermatozoa at the same rate as lectin receptors (25), these results show that there is bulk membrane flow over the pseudopod with assembly at the tip and apparent disassembly at the base. There are no vesicles visible at either the pseudopodial tip or base, so these spermatozoa must have a novel mechanism for insertion and uptake of membrane components. This membrane flow could provide the forward propulsion of spermatozoa attached to a substrate by their pseudopods.

  6. Bayesian Inference of Forces Causing Cytoplasmic Streaming in Caenorhabditis elegans Embryos and Mouse Oocytes

    Science.gov (United States)

    Niwayama, Ritsuya; Nagao, Hiromichi; Kitajima, Tomoya S.; Hufnagel, Lars; Shinohara, Kyosuke; Higuchi, Tomoyuki; Ishikawa, Takuji

    2016-01-01

    Cellular structures are hydrodynamically interconnected, such that force generation in one location can move distal structures. One example of this phenomenon is cytoplasmic streaming, whereby active forces at the cell cortex induce streaming of the entire cytoplasm. However, it is not known how the spatial distribution and magnitude of these forces move distant objects within the cell. To address this issue, we developed a computational method that used cytoplasm hydrodynamics to infer the spatial distribution of shear stress at the cell cortex induced by active force generators from experimentally obtained flow field of cytoplasmic streaming. By applying this method, we determined the shear-stress distribution that quantitatively reproduces in vivo flow fields in Caenorhabditis elegans embryos and mouse oocytes during meiosis II. Shear stress in mouse oocytes were predicted to localize to a narrower cortical region than that with a high cortical flow velocity and corresponded with the localization of the cortical actin cap. The predicted patterns of pressure gradient in both species were consistent with species-specific cytoplasmic streaming functions. The shear-stress distribution inferred by our method can contribute to the characterization of active force generation driving biological streaming. PMID:27472658

  7. Organ Length Control by an ADAMTS Extracellular Protease in Caenorhabditis elegans

    Science.gov (United States)

    Shibata, Yukimasa; Kawakado, Yuri; Hori, Noriyoshi; Tanaka, Kota; Inoue, Ryo; Takano, Tomomi; Kubota, Yukihiko; Nishiwaki, Kiyoji

    2016-01-01

    MIG-17, a secreted protease of the ADAMTS family, acts in the directed migration of gonadal distal tip cells (DTCs) through regulation of the gonadal basement membrane in Caenorhabditis elegans. Here, we show that MIG-17 is also required for the control of pharynx elongation during animal growth. We found that the pharynx was elongated in mig-17 mutants compared with wild type. MIG-17 localized to the pharyngeal basement membrane as well as to the gonadal basement membrane. The number of nuclei in the pharynx, and the pumping rate of the pharynx, were not affected in mig-17 mutants, suggesting that cells constituting the pharynx are elongated, although the pharynx functions normally in these mutants. In contrast to the control of DTC migration, MIG-18, a secreted cofactor of MIG-17, was not essential for pharynx length regulation. In addition, the downstream pathways of MIG-17 involving LET-2/type IV collagen, FBL-1/fibulin-1, and NID-1/nidogen, partly diverged from those in gonad development. These results indicate that basement membrane remodeling is important for organ length regulation, and suggest that MIG-17/ADAMTS functions in similar but distinct molecular machineries in pharyngeal and gonadal basement membranes. PMID:26994289

  8. A Forward Genetic Screen for Molecules Involved in Pheromone-Induced Dauer Formation in Caenorhabditis elegans

    Science.gov (United States)

    Neal, Scott J.; Park, JiSoo; DiTirro, Danielle; Yoon, Jason; Shibuya, Mayumi; Choi, Woochan; Schroeder, Frank C.; Butcher, Rebecca A.; Kim, Kyuhyung; Sengupta, Piali

    2016-01-01

    Animals must constantly assess their surroundings and integrate sensory cues to make appropriate behavioral and developmental decisions. Pheromones produced by conspecific individuals provide critical information regarding environmental conditions. Ascaroside pheromone concentration and composition are instructive in the decision of Caenorhabditis elegans to either develop into a reproductive adult or enter into the stress-resistant alternate dauer developmental stage. Pheromones are sensed by a small set of sensory neurons, and integrated with additional environmental cues, to regulate neuroendocrine signaling and dauer formation. To identify molecules required for pheromone-induced dauer formation, we performed an unbiased forward genetic screen and identified phd (pheromone response-defective dauer) mutants. Here, we describe new roles in dauer formation for previously identified neuronal molecules such as the WD40 domain protein QUI-1 and MACO-1 Macoilin, report new roles for nociceptive neurons in modulating pheromone-induced dauer formation, and identify tau tubulin kinases as new genes involved in dauer formation. Thus, phd mutants define loci required for the detection, transmission, or integration of pheromone signals in the regulation of dauer formation. PMID:26976437

  9. Long astral microtubules and RACK-1 stabilize polarity domains during maintenance phase in Caenorhabditis elegans embryos.

    Directory of Open Access Journals (Sweden)

    Erkang Ai

    Full Text Available Cell polarity is a very well conserved process important for cell differentiation, cell migration, and embryonic development. After the establishment of distinct cortical domains, polarity cues have to be stabilized and maintained within a fluid and dynamic membrane to achieve proper cell asymmetry. Microtubules have long been thought to deliver the signals required to polarize a cell. While previous studies suggest that microtubules play a key role in the establishment of polarity, the requirement of microtubules during maintenance phase remains unclear. In this study, we show that depletion of Caenorhabditis elegans RACK-1, which leads to short astral microtubules during prometaphase, specifically affects maintenance of cortical PAR domains and Dynamin localization. We then investigated the consequence of knocking down other factors that also abolish astral microtubule elongation during polarity maintenance phase. We found a correlation between short astral microtubules and the instability of PAR-6 and PAR-2 domains during maintenance phase. Our data support a necessary role for astral microtubules in the maintenance phase of cell polarity.

  10. Expression of Caenorhabditis elegans antimicrobial peptide NLP-31 in Escherichia coli

    Science.gov (United States)

    Lim, Mei-Perng; Nathan, Sheila

    2014-09-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a fulminant disease endemic in Southeast Asia and Northern Australia. The standardized form of therapy is antibiotics treatment; however, the bacterium has become increasingly resistant to these antibiotics. This has spurred the need to search for alternative therapeutic agents. Antimicrobial peptides (AMPs) are small proteins that possess broad-spectrum antimicrobial activity. In a previous study, the nematode Caenorhabditis elegans was infected by B. pseudomallei and a whole animal transcriptome analysis identified a number of AMP-encoded genes which were induced significantly in the infected worms. One of the AMPs identified is NLP-31 and to date, there are no reports of anti-B. pseudomallei activity demonstrated by NLP-31. To produce NLP-31 protein for future studies, the gene encoding for NLP-31 was cloned into the pET32b expression vector and transformed into Escherichia coli BL21(DE3). Protein expression was induced with 1 mM IPTG for 20 hours at 20°C and recombinant NLP-31 was detected in the soluble fraction. Taken together, a simple optimized heterologous production of AMPs in an E. coli expression system has been successfully developed.

  11. Multiple Functions of Let-23, a Caenorhabditis Elegans Receptor Tyrosine Kinase Gene Required for Vulval Induction

    Science.gov (United States)

    Aroian, R. V.; Sternberg, P. W.

    1991-01-01

    The let-23 gene, which encodes a putative tyrosine kinase of the epidermal growth factor (EGF) receptor subfamily, has multiple functions during Caenorhabditis elegans development. We show that let-23 function is required for vulval precursor cells (VPCs) to respond to the signal that induces vulval differentiation: a complete loss of let-23 function results in no induction. However, some let-23 mutations that genetically reduce but do not eliminate let-23 function result in VPCs apparently hypersensitive to inductive signal: as many as five of six VPCs can adopt vulval fates, in contrast to the three that normally do. These results suggest that the let-23 receptor tyrosine kinase controls two opposing pathways, one that stimulates vulval differentiation and another that negatively regulates vulval differentiation. Furthermore, analysis of 16 new let-23 mutations indicates that the let-23 kinase functions in at least five tissues. Since various let-23 mutant phenotypes can be obtained independently, the let-23 gene is likely to have tissue-specific functions. PMID:2071015

  12. Extracellular domain determinants of LET-23 (EGF) receptor tyrosine kinase activity in Caenorhabditis elegans.

    Science.gov (United States)

    Moghal, Nadeem; Sternberg, Paul W

    2003-08-21

    Negative regulation of ErbB/EGFR signalling pathways is important for normal development and the prevention of cancer. In a genetic screen to uncover mechanisms that negatively regulate ErbB signalling in Caenorhabditis elegans, we isolated a second-site mutation (sy621) that promotes the activity of a gain-of-function allele (sa62gf) of the let-23 (EGF) receptor tyrosine kinase. We show that activation by the sa62 mutation (C359Y) likely results from a break in the conserved disulphide-bonded eighth module at the junction of CR1 and L2. The sy621 mutation causes a G270E change in the third disulphide-bonded module of CR1, and causes no phenotype on its own, but cooperates with the sa62 mutation to promote receptor activity. Although both sa62 single- and double-mutant receptors can function in the absence of ligand, they can be further activated by ligand. Our results support the current model for ligand-induced dimerization based on the recent crystal structures of HER3 and the EGFR, and provide more evidence for the generation of distinctly activated ErbB family members through mutation.

  13. VANG-1 and PRKL-1 cooperate to negatively regulate neurite formation in Caenorhabditis elegans.

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    Leticia Sanchez-Alvarez

    2011-09-01

    Full Text Available Neuritogenesis is a critical early step in the development and maturation of neurons and neuronal circuits. While extracellular directional cues are known to specify the site and orientation of nascent neurite formation in vivo, little is known about the genetic pathways that block inappropriate neurite emergence in order to maintain proper neuronal polarity. Here we report that the Caenorhabditis elegans orthologues of Van Gogh (vang-1, Prickle (prkl-1, and Dishevelled (dsh-1, core components of planar cell polarity (PCP signaling, are required in a subset of peripheral motor neurons to restrict neurite emergence to a specific organ axis. In loss-of-function mutants, neurons display supernumerary neurites that extend inappropriately along the orthogonal anteroposterior (A/P body axis. We show that autonomous and non-autonomous gene activities are required early and persistently to inhibit the formation or consolidation of growth cone protrusions directed away from organ precursor cells. Furthermore, prkl-1 overexpression is sufficient to suppress neurite formation and reorient neuronal polarity in a vang-1- and dsh-1-dependent manner. Our findings suggest a novel role for a PCP-like pathway in maintaining polarized neuronal morphology by inhibiting neuronal responses to extrinsic or intrinsic cues that would otherwise promote extraneous neurite formation.

  14. Succinylated Octopamine Ascarosides and a New Pathway of Biogenic Amine Metabolism in Caenorhabditis elegans*

    Science.gov (United States)

    Artyukhin, Alexander B.; Yim, Joshua J.; Srinivasan, Jagan; Izrayelit, Yevgeniy; Bose, Neelanjan; von Reuss, Stephan H.; Jo, Yeara; Jordan, James M.; Baugh, L. Ryan; Cheong, Micheong; Sternberg, Paul W.; Avery, Leon; Schroeder, Frank C.

    2013-01-01

    The ascarosides, small-molecule signals derived from combinatorial assembly of primary metabolism-derived building blocks, play a central role in Caenorhabditis elegans biology and regulate many aspects of development and behavior in this model organism as well as in other nematodes. Using HPLC-MS/MS-based targeted metabolomics, we identified novel ascarosides incorporating a side chain derived from succinylation of the neurotransmitter octopamine. These compounds, named osas#2, osas#9, and osas#10, are produced predominantly by L1 larvae, where they serve as part of a dispersal signal, whereas these ascarosides are largely absent from the metabolomes of other life stages. Investigating the biogenesis of these octopamine-derived ascarosides, we found that succinylation represents a previously unrecognized pathway of biogenic amine metabolism. At physiological concentrations, the neurotransmitters serotonin, dopamine, and octopamine are converted to a large extent into the corresponding succinates, in addition to the previously described acetates. Chemically, bimodal deactivation of biogenic amines via acetylation and succinylation parallels posttranslational modification of proteins via acetylation and succinylation of l-lysine. Our results reveal a small-molecule connection between neurotransmitter signaling and interorganismal regulation of behavior and suggest that ascaroside biosynthesis is based in part on co-option of degradative biochemical pathways. PMID:23689506

  15. A Forward Genetic Screen for Molecules Involved in Pheromone-Induced Dauer Formation in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Scott J. Neal

    2016-05-01

    Full Text Available Animals must constantly assess their surroundings and integrate sensory cues to make appropriate behavioral and developmental decisions. Pheromones produced by conspecific individuals provide critical information regarding environmental conditions. Ascaroside pheromone concentration and composition are instructive in the decision of Caenorhabditis elegans to either develop into a reproductive adult or enter into the stress-resistant alternate dauer developmental stage. Pheromones are sensed by a small set of sensory neurons, and integrated with additional environmental cues, to regulate neuroendocrine signaling and dauer formation. To identify molecules required for pheromone-induced dauer formation, we performed an unbiased forward genetic screen and identified phd (pheromone response-defective dauer mutants. Here, we describe new roles in dauer formation for previously identified neuronal molecules such as the WD40 domain protein QUI-1 and MACO-1 Macoilin, report new roles for nociceptive neurons in modulating pheromone-induced dauer formation, and identify tau tubulin kinases as new genes involved in dauer formation. Thus, phd mutants define loci required for the detection, transmission, or integration of pheromone signals in the regulation of dauer formation.

  16. Targeted metabolomics reveals a male pheromone and sex-specific ascaroside biosynthesis in Caenorhabditis elegans.

    Science.gov (United States)

    Izrayelit, Yevgeniy; Srinivasan, Jagan; Campbell, Sydney L; Jo, Yeara; von Reuss, Stephan H; Genoff, Margaux C; Sternberg, Paul W; Schroeder, Frank C

    2012-08-17

    In the model organism Caenorhabditis elegans, a class of small molecule signals called ascarosides regulate development, mating, and social behaviors. Ascaroside production has been studied in the predominant sex, the hermaphrodite, but not in males, which account for less than 1% of wild-type worms grown under typical laboratory conditions. Using HPLC-MS-based targeted metabolomics, we show that males also produce ascarosides and that their ascaroside profile differs markedly from that of hermaphrodites. Whereas hermaphrodite ascaroside profiles are dominated by ascr#3, containing an α,β-unsaturated fatty acid, males predominantly produce the corresponding dihydro-derivative ascr#10. This small structural modification profoundly affects signaling properties: hermaphrodites are retained by attomole-amounts of male-produced ascr#10, whereas hermaphrodite-produced ascr#3 repels hermaphrodites and attracts males. Male production of ascr#10 is population density-dependent, indicating sensory regulation of ascaroside biosynthesis. Analysis of gene expression data supports a model in which sex-specific regulation of peroxisomal β-oxidation produces functionally different ascaroside profiles.

  17. Succinylated octopamine ascarosides and a new pathway of biogenic amine metabolism in Caenorhabditis elegans.

    Science.gov (United States)

    Artyukhin, Alexander B; Yim, Joshua J; Srinivasan, Jagan; Izrayelit, Yevgeniy; Bose, Neelanjan; von Reuss, Stephan H; Jo, Yeara; Jordan, James M; Baugh, L Ryan; Cheong, Micheong; Sternberg, Paul W; Avery, Leon; Schroeder, Frank C

    2013-06-28

    The ascarosides, small-molecule signals derived from combinatorial assembly of primary metabolism-derived building blocks, play a central role in Caenorhabditis elegans biology and regulate many aspects of development and behavior in this model organism as well as in other nematodes. Using HPLC-MS/MS-based targeted metabolomics, we identified novel ascarosides incorporating a side chain derived from succinylation of the neurotransmitter octopamine. These compounds, named osas#2, osas#9, and osas#10, are produced predominantly by L1 larvae, where they serve as part of a dispersal signal, whereas these ascarosides are largely absent from the metabolomes of other life stages. Investigating the biogenesis of these octopamine-derived ascarosides, we found that succinylation represents a previously unrecognized pathway of biogenic amine metabolism. At physiological concentrations, the neurotransmitters serotonin, dopamine, and octopamine are converted to a large extent into the corresponding succinates, in addition to the previously described acetates. Chemically, bimodal deactivation of biogenic amines via acetylation and succinylation parallels posttranslational modification of proteins via acetylation and succinylation of L-lysine. Our results reveal a small-molecule connection between neurotransmitter signaling and interorganismal regulation of behavior and suggest that ascaroside biosynthesis is based in part on co-option of degradative biochemical pathways.

  18. A Forward Genetic Screen for Molecules Involved in Pheromone-Induced Dauer Formation in Caenorhabditis elegans.

    Science.gov (United States)

    Neal, Scott J; Park, JiSoo; DiTirro, Danielle; Yoon, Jason; Shibuya, Mayumi; Choi, Woochan; Schroeder, Frank C; Butcher, Rebecca A; Kim, Kyuhyung; Sengupta, Piali

    2016-05-03

    Animals must constantly assess their surroundings and integrate sensory cues to make appropriate behavioral and developmental decisions. Pheromones produced by conspecific individuals provide critical information regarding environmental conditions. Ascaroside pheromone concentration and composition are instructive in the decision of Caenorhabditis elegans to either develop into a reproductive adult or enter into the stress-resistant alternate dauer developmental stage. Pheromones are sensed by a small set of sensory neurons, and integrated with additional environmental cues, to regulate neuroendocrine signaling and dauer formation. To identify molecules required for pheromone-induced dauer formation, we performed an unbiased forward genetic screen and identified phd (pheromone response-defective dauer) mutants. Here, we describe new roles in dauer formation for previously identified neuronal molecules such as the WD40 domain protein QUI-1 and MACO-1 Macoilin, report new roles for nociceptive neurons in modulating pheromone-induced dauer formation, and identify tau tubulin kinases as new genes involved in dauer formation. Thus, phd mutants define loci required for the detection, transmission, or integration of pheromone signals in the regulation of dauer formation.

  19. Expression of hepatitis B virus surface antigens induces defective gonad phenotypes in Caenorhabditis elegans

    Science.gov (United States)

    Chen, Yi-Yin; Lee, Li-Wei; Hong, Wei-Ning; Lo, Szecheng J

    2017-01-01

    AIM To test whether a simple animal, Caenorhabditis elegans (C. elegans), can be used as an alternative model to study the interaction between hepatitis B virus antigens (HBsAg) and host factors. METHODS Three plasmids that were able to express the large, middle and small forms of HBsAgs (LHBsAg, MHBsAg, and SHBsAg, respectively) driven by a ubiquitous promoter (fib-1) and three that were able to express SHBsAg driven by different tissue-specific promoters were constructed and microinjected into worms. The brood size, egg-laying rate, and gonad development of transgenic worms were analyzed using microscopy. Levels of mRNA related to endoplasmic reticulum stress, enpl-1, hsp-4, pdi-3 and xbp-1, were determined using reverse transcription polymerase reaction (RT-PCRs) in three lines of transgenic worms and dithiothreitol (DTT)-treated wild-type worms. RESULTS Severe defects in egg-laying, decreases in brood size, and gonad retardation were observed in transgenic worms expressing SHBsAg whereas moderate defects were observed in transgenic worms expressing LHBsAg and MHBsAg. RT-PCR analysis revealed that enpl-1, hsp-4 and pdi-3 transcripts were significantly elevated in worms expressing LHBsAg and MHBsAg and in wild-type worms pretreated with DTT. By contrast, only pdi-3 was increased in worms expressing SHBsAg. To further determine which tissue expressing SHBsAg could induce gonad retardation, we substituted the fib-1 promoter with three tissue-specific promoters (myo-2 for the pharynx, est-1 for the intestines and mec-7 for the neurons) and generated corresponding transgenic animals. Moderate defective phenotypes were observed in worms expressing SHBsAg in the pharynx and intestines but not in worms expressing SHBsAg in the neurons, suggesting that the secreted SHBsAg may trigger a cross-talk signal between the digestive track and the gonad resulting in defective phenotypes. CONCLUSION Ectopic expression of three forms of HBsAg that causes recognizable phenotypes in

  20. Comparative Study of Several Behaviors in Caenorhabditis Elegans Following High-Let Radiation Exposure

    Science.gov (United States)

    Sakashita, Tetsuya

    Learning and behavioral impairments following ionizing radiation exposure are an important potential risk in manned space missions. We previously reported the effects of γ-ray exposure on olfactory adaptation [1], salt chemotaxis learning [2], and locomotion - learning behavior relationship [3] in Caenorhabditis elegans. However, little is known about the effects of high linear energy transfer (LET) radiation. We investigated various behavioral responses of wellfed adult Caenorhabditis elegans exposed to accelerated carbon ions (1 2C, 18.3M eV /u, LET = 113.3keV /µm). Following carbon-ion irradiation, locomotion, basal slowing response and salt chemotaxis learning were not significantly affected, whereas chemosensation to NaCl of animals during learning was altered. These results suggest that sensitivity of the C. elegans nervous system to high-LET heavy ions differs with the types of behaviors. References: [1] Sakashita et al., Biol. Sci. Space 21, 117-20 (2007), [2] Sakashita et al., FASEB J 22, 713-20 (2008), [3] Sakashita et al., J. Radiat. Res. 49, in press (2008).

  1. cis-Regulatory control of three cell fate-specific genes in vulval organogenesis of Caenorhabditis elegans and C. briggsae.

    Science.gov (United States)

    Kirouac, Martha; Sternberg, Paul W

    2003-05-01

    The great-grandprogeny of the Caenorhabditis elegans vulval precursor cells (VPCs) adopt one of the final vulA, B1, B2, C, D, E, and F cell fates in a precise spatial pattern. This pattern of vulval cell types is likely to depend on the cis-regulatory regions of the transcriptional targets of intercellular signals in vulval development. egl-17, zmp-1, and cdh-3 are expressed differentially in the developing vulva cells, providing a potential readout for different signaling pathways. To understand how such pathways interact to specify unique vulval cell types in a precise pattern, we have identified cis-regulatory regions sufficient to confer vulval cell type-specific regulation when fused in cis to the basal pes-10 promoter. We have identified the C. briggsae homologs of these three genes, with their corresponding control regions, and tested these regions in both C. elegans and C. briggsae. These regions of similarity in C. elegans and C. briggsae upstream of egl-17, zmp-1, and cdh-3 promote expression in vulval cells and the anchor cell (AC). By using the cis-regulatory analysis and phylogenetic footprinting, we have identified overrepresented sequences involved in conferring vulval and AC expression.

  2. 线虫脂肪模型研究%Research on Caenorhabditis elegans as model for obesity

    Institute of Scientific and Technical Information of China (English)

    徐蔓玲; 赵阳; 贾熙华; 季宇彬

    2014-01-01

    Obesity is a kind of chronic disease with the fatty acid accumulation increased . Studying on the model of organism can discover the obesity disease -causing genes or related pathogenic factors , and find potential drug targets .The progress of research on Caenorhabdi-tis elegans as a model for fatty was summarized in this paper .The key genes and core path-ways in fatty acid metabolism was involved .The data obtained in Caenorhabditis elegans on fatty storage control will contribute largely to the study on metabolism related diseases , such as obesity in human beings .C.elegans may be invaluable in the development of reducing fat and body weightdrugs in the future .%肥胖是一种脂肪酸积累增加的慢性疾病,采用研究模式生物的方法可以有助于探明肥胖产生的致病基因或致病相关因子,进而寻找可能的药物靶点。综述了国内外对线虫脂肪模型的研究进展,分析了线虫体内脂肪酸代谢途径的关键基因和核心通路。线虫脂肪代谢调节研究工作对人类肥胖症等代谢疾病的研究具有重要的提示作用,利用线虫脂肪模型研究降脂减肥药物具有广阔的应用前景。

  3. Using the nematode Caenorhabditis elegans as a model animal for assessing the toxicity induced by microcystin-LR

    Institute of Scientific and Technical Information of China (English)

    LI Yunhui; WANG Yang; YIN Lihong; PU Yuepu; WANG Dayong

    2009-01-01

    Among more than 75 variants of microcystin (MC), microcystin-LR (MC-LR) is one of the most common toxins. In this study, the feasibility of using Caenorhabditis elegans to evaluate MC-LR toxicity was studied. C. elegans was treated with MC-LR at different concentrations ranging from 0.1 to 80 μg/L. The results showed that MC-LR could reduce lifespan, delay development, lengthen generation times, decrease brood sizes, suppress locomotion behaviors, and decreases hsp-16-2-gfp expression. The endpoints of generation time, brood size, and percentage of the population expressing hsp16-2-gfp were very sensitive to 1.0 μg/L of MC-LR, and would be more useful for the evaluation of MC-LR toxicity. Furthermore, the tissue-specific hsp16-2-gfp expressions were investigated in MC-LR-exposed animals, and the nervous system and intestine were primarily effected by MC-LR. Therefore, the generation time, brood size, and hsp16-2-gfp expression in C. elegans can be explored to serve as valuable endpoints for evaluating the potential toxicity from MC-LR exposure.

  4. A microfluidic device for the continuous culture and analysis of Caenorhabditis elegans in a toxic aqueous environment

    Science.gov (United States)

    Jung, Jaehoon; Nakajima, Masahiro; Tajima, Hirotaka; Huang, Qiang; Fukuda, Toshio

    2013-08-01

    The nematode Caenorhabditis elegans (C. elegans) receives attention as a bioindicator, and the C. elegans condition has been recently analyzed using microfluidic devices equipped with an imaging system. To establish a method without an imaging system, we have proposed a novel microfluidic device with which to analyze the condition of C. elegans from the capacitance change using a pair of micro-electrodes. The device was designed to culture C. elegans, to expose C. elegans to an external stimulus, such as a chemical or toxicant, and to measure the capacitance change which indicates the condition of C. elegans. In this study, to demonstrate the capability of our device in a toxic aqueous environment, the device was applied to examine the effect of cadmium on C. elegans. Thirty L4 larval stage C. elegans were divided into three groups. One group was a control group and the other groups were exposed to cadmium solutions with concentrations of 5% and 10% LC50 for 24 h. The capacitance change and the body volume of C. elegans as a reference were measured four times and we confirmed the correlation between them. It shows that our device can analyze the condition of C. elegans without an imaging system.

  5. Oxaloacetate supplementation increases lifespan in Caenorhabditis elegans through an AMPK/FOXO-dependent pathway.

    Science.gov (United States)

    Williams, David S; Cash, Alan; Hamadani, Lara; Diemer, Tanja

    2009-12-01

    Reduced dietary intake increases lifespan in a wide variety of organisms. It also retards disease progression. We tested whether dietary supplementation of citric acid cycle metabolites could mimic this lifespan effect. We report that oxaloacetate supplementation increased lifespan in Caenorhabditis elegans. The increase was dependent on the transcription factor, FOXO/DAF-16, and the energy sensor, AMP-activated protein kinase, indicating involvement of a pathway that is also required for lifespan extension through dietary restriction. These results demonstrate that supplementation of the citric acid cycle metabolite, oxaloacetate, influences a longevity pathway, and suggest a tractable means of introducing the health-related benefits of dietary restriction.

  6. Developmental defects in a Caenorhabditis elegans model for type III galactosemia.

    Science.gov (United States)

    Brokate-Llanos, Ana M; Monje, José M; Murdoch, Piedad Del Socorro; Muñoz, Manuel J

    2014-12-01

    Type III galactosemia is a metabolic disorder caused by reduced activity of UDP-galactose-4-epimerase, which participates in galactose metabolism and the generation of various UDP-sugar species. We characterized gale-1 in Caenorhabditis elegans and found that a complete loss-of-function mutation is lethal, as has been hypothesized for humans, whereas a nonlethal partial loss-of-function allele causes a variety of developmental abnormalities, likely resulting from the impairment of the glycosylation process. We also observed that gale-1 mutants are hypersensitive to galactose as well as to infections. Interestingly, we found interactions between gale-1 and the unfolded protein response.

  7. Centrosome movement in the early divisions of Caenorhabditis elegans: A cortical site determining centrosome position

    Energy Technology Data Exchange (ETDEWEB)

    Hyman, A.A. (Medical Research Council, Cambridge (England))

    1989-09-01

    In Caenorhabditis elegans embryos, early blastomeres of the P cell lineage divide successively on the same axis. This axis is a consequence of the specific rotational movement of the pair of centrosomes and nucleus. A laser has been used to perturb the centrosome movements that determine the pattern of early embryonic divisions. The results support a previously proposed model in which a centrosome rotates towards its correct position by shortening of connections, possibly microtubules, between a centrosome and a defined site on the cortex of the embryo.

  8. Selective visualization of fluorescent sterols in Caenorhabditis elegans by bleach-rate-based image segmentation

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Landt Larsen, Ane; Færgeman, Nils J.

    2010-01-01

    The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method...... to detect DHE selectively, based on its rapid bleaching kinetics compared to cellular autofluorescence. Worms were repeatedly imaged on an ultraviolet-sensitive wide field (UV-WF) microscope, and bleaching kinetics of DHE were fitted on a pixel-basis to mathematical models describing the intensity decay...... autofluorescence and compare our method with three-photon excitation microscopy of sterol in selected tissues. Bleach-rate-based UV-WF imaging is a useful tool for genetic screening experiments on sterol transport, as exemplified by RNA interference against the rme-2 gene coding for the yolk receptor and for worm...

  9. Genes required for the common miracle of fertilization in Caenorhabditis elegans.

    Science.gov (United States)

    Singson, Andrew; Hang, Julie S; Parry, Jean M

    2008-01-01

    Fertilization involves multiple layers of sperm-egg interactions that lead to gamete fusion and egg activation. There must be specific molecules required for these interactions. The challenge is to determine the identity of the genes encoding these molecules and how their protein products function. The nematode worm Caenorhabditis elegans has emerged as an efficient model system for gene discovery and understanding the molecular mechanisms of fertilization. The primary advantage of the C. elegans system is the ability to isolate and maintain mutants that affect sperm or eggs and no other cells. In this review we describe progress and challenges in the analysis of genes required for gamete interactions and egg activation in the worm.

  10. Escherichia coli carbon source metabolism affects longevity of its predator Caenorhabditis elegans.

    Science.gov (United States)

    Brokate-Llanos, Ana María; Garzón, Andrés; Muñoz, Manuel J

    2014-01-01

    Nutrition is probably the most determinant factor affecting aging. Microorganisms of the intestinal flora lay in the interface between available nutrients and nutrients that are finally absorbed by multicellular organisms. They participate in the processing and transformation of these nutrients in a symbiotic or commensalistic relationship. In addition, they can also be pathogens. Alive Escherichia coli OP50 are usually used to culture the bacteriovorus nematode Caenorhabditis elegans. Here, we report a beneficial effect of low concentration of saccharides on the longevity of C. elegans. This effect is only observed when the bacterium can metabolize the sugar, suggesting that physiological changes in the bacterium feeding on the saccharides are the cause of this beneficial effect.

  11. The impact of bacterial diet on the migration and navigation of Caenorhabditis elegans.

    Science.gov (United States)

    Rodger, S; Griffiths, B S; McNicol, J W; Wheatley, R W; Young, I M

    2004-10-01

    Can diet have a significant impact on the ability of organisms to sense and locate food? Focusing on the bacterial feeder Caenorhabditis elegans, we investigated what effect preconditioning on a range of bacterial substrates had on the subsequent chemotaxis process involved in the nematode locating other bacterial populations. Remarkably, we found that C. elegans, initially fed on a diet of Escherichia coli OP50, was significantly impaired in finding E. coli OP50 populations, compared to other available bacterial populations (P <0.001). We found similar results for another bacterial feeding nematode species, suggesting that a general "substrate legacy" may operate across a wide range of organisms. We discuss this important finding with respect to the variation in response exhibited within a given nematode population, and the impact nematode migration has on bacterial dispersal in the environment.

  12. crm-1 facilitates BMP signaling to control body size in Caenorhabditis elegans.

    Science.gov (United States)

    Fung, Wong Yan; Fat, Ko Frankie Chi; Eng, Cheah Kathryn Song; Lau, Chow King

    2007-11-01

    We have identified in Caenorhabditis elegans a homologue of the vertebrate Crim1, crm-1, which encodes a putative transmembrane protein with multiple cysteine-rich (CR) domains known to have bone morphogenetic proteins (BMPs) binding activity. Using the body morphology of C. elegans as an indicator, we showed that attenuation of crm-1 activity leads to a small body phenotype reminiscent of that of BMP pathway mutants. We showed that the crm-1 loss-of-function phenotype can be rescued by constitutive supply of sma-4 activity. crm-1 can enhance BMP signaling and this activity is dependent on the presence of the DBL-1 ligand and its receptors. crm-1 is expressed in neurons at the ventral nerve cord, where the DBL-1 ligand is produced. However, ectopic expression experiments reveal that crm-1 gene products act outside the DBL-1 producing cells and function non-autonomously to facilitate dbl/sma pathway signaling to control body size.

  13. Multi-Toxic Endpoints of the Foodborne Mycotoxins in Nematode Caenorhabditis elegans.

    Science.gov (United States)

    Yang, Zhendong; Xue, Kathy S; Sun, Xiulan; Tang, Lili; Wang, Jia-Sheng

    2015-12-02

    Aflatoxins B₁ (AFB₁), deoxynivalenol (DON), fumonisin B₁ (FB₁), T-2 toxin (T-2), and zearalenone (ZEA) are the major foodborne mycotoxins of public health concerns. In the present study, the multiple toxic endpoints of these naturally-occurring mycotoxins were evaluated in Caenorhabditis elegans model for their lethality, toxic effects on growth and reproduction, as well as influence on lifespan. We found that the lethality endpoint was more sensitive for T-2 toxicity with the EC50 at 1.38 mg/L, the growth endpoint was relatively sensitive for AFB₁ toxic effects, and the reproduction endpoint was more sensitive for toxicities of AFB₁, FB₁, and ZEA. Moreover, the lifespan endpoint was sensitive to toxic effects of all five tested mycotoxins. Data obtained from this study may serve as an important contribution to knowledge on assessment of mycotoxin toxic effects, especially for assessing developmental and reproductive toxic effects, using the C. elegans model.

  14. Heat shock factor 1 prevents the reduction in thrashing due to heat shock in Caenorhabditis elegans.

    Science.gov (United States)

    Furuhashi, Tsubasa; Sakamoto, Kazuichi

    2015-07-01

    Heat shock factor 1 (HSF-1) is activated by heat stress and induces the expression of heat shock proteins. However, the role of HSF-1 in thermotolerance remains unclear. We previously reported that heat stress reversibly reduces thrashing movement in Caenorhabditis elegans. In this study, we analyzed the function of HSF-1 on thermotolerance by monitoring thrashing movement. hsf-1 RNAi suppressed the restoration of thrashing reduced by heat stress. In contrast, hsf-1 knockdown cancelled prevention of movement reduction in insulin/IGF-1-like growth factor 1 receptor (daf-2) mutant, but didn't suppress thrashing restoration in daf-2 mutant. In addition, hsf-1 RNAi accelerated the reduction of thrashing in heat-shocked wild-type C. elegans. And, daf-16 KO didn't accelerate the reduction of thrashing by heat stress. Taken together, these results suggest that HSF-1 prevents the reduction of thrashing caused by heat shock.

  15. Multi-environment model estimation for motility analysis of Caenorhabditis Elegans

    CERN Document Server

    Sznitman, Raphael; Hager, Gregory D; Arratia, Paulo E; Sznitman, Josue

    2010-01-01

    The nematode Caenorhabditis elegans is a well-known model organism used to investigate fundamental questions in biology. Motility assays of this small roundworm are designed to study the relationships between genes and behavior. Commonly, motility analysis is used to classify nematode movements and characterize them quantitatively. Over the past years, C. elegans' motility has been studied across a wide range of environments, including crawling on substrates, swimming in fluids, and locomoting through microfluidic substrates. However, each environment often requires customized image processing tools relying on heuristic parameter tuning. In the present study, we propose a novel Multi-Environment Model Estimation (MEME) framework for automated image segmentation that is versatile across various environments. The MEME platform is constructed around the concept of Mixture of Gaussian (MOG) models, where statistical models for both the background environment and the nematode appearance are explicitly learned and ...

  16. Chlorophyll enhances oxidative stress tolerance in Caenorhabditis elegans and extends its lifespan

    Science.gov (United States)

    Wang, Erjia

    2016-01-01

    Green vegetables are thought to be responsible for several beneficial properties such as antioxidant, anti-mutagenic, and detoxification activities. It is not known whether these effects are due to chlorophyll which exists in large amounts in many foods or result from other secondary metabolites. In this study, we used the model system Caenorhabditis elegans to investigate the anti-oxidative and anti-aging effects of chlorophyll in vivo. We found that chlorophyll significantly improves resistance to oxidative stress. It also enhances the lifespan of C. elegans by up to 25% via activation of the DAF-16/FOXO-dependent pathway. The results indicate that chlorophyll is absorbed by the worms and is thus bioavailable, constituting an important prerequisite for antioxidant and longevity-promoting activities inside the body. Our study thereby supports the view that green vegetables may also be beneficial for humans. PMID:27077003

  17. PUF-8, a Pumilio homolog, inhibits the proliferative fate in the Caenorhabditis elegans germline.

    Science.gov (United States)

    Racher, Hilary; Hansen, Dave

    2012-10-01

    Stem cell populations are maintained by keeping a balance between self-renewal (proliferation) and differentiation of dividing stem cells. Within the Caenorhabditis elegans germline, the key regulator maintaining this balance is the canonical Notch signaling pathway, with GLP-1/Notch activity promoting the proliferative fate. We identified the Pumilio homolog, PUF-8, as an inhibitor of the proliferative fate of stem cells in the C. elegans germline. puf-8(0) strongly enhances overproliferation of glp-1(gf) mutants and partially suppresses underproliferation of a weak glp-1(lf) mutant. The germline tumor that is formed in a puf-8(0); glp-1(gf) double mutant is due to a failure of germ cells to enter meiotic prophase. puf-8 likely inhibits the proliferative fate through negatively regulating GLP-1/Notch signaling or by functioning parallel to it.

  18. Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension

    Directory of Open Access Journals (Sweden)

    Ueno Kazuko

    2009-04-01

    Full Text Available Abstract Background Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher et al. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in C. elegans and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze in silico models incorporating the use of model checking approach. Results A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules – Rule I and Rule II – to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from in silico and in vivo experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in

  19. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Susan K Glendinning

    Full Text Available Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316 under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in

  20. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

    Science.gov (United States)

    Glendinning, Susan K; Buckingham, Steven D; Sattelle, David B; Wonnacott, Susan; Wolstenholme, Adrian J

    2011-01-01

    Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl) gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316) under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in some assays. C

  1. Meeting report: 2012 Caenorhabditis elegans Neurobiology meeting, EMBL Advanced Training Centre, Germany.

    Science.gov (United States)

    Kearn, James; Dallière, Nicolas; Dillon, James

    2013-06-01

    Some of the finest minds in the field of Caenorhabditis elegans neurobiology were brought together from 14 June to 17 June 2012 in the small, quaint and picturesque German city of Heidelberg for the biannual C. elegans neurobiology conference. Held at the EMBL Advanced Training Centre and wonderfully organised by Diah Yulianti, Jean-Louis Bessereau, Gert Jansen and William Schafer, the meeting contained 62 verbal presentations and hundreds of posters that were displayed around the double-helical walkways that looped throughout the conference centre. Presentations on recent advances in microfluidics, cell ablation and targeted gene expression exemplified the strengths of C. elegans as a model organism, with these advances allowing detailed high-throughput analysis and study. Interesting behaviours that were previously poorly characterised were widely discussed, as were the advantages of C. elegans as a model for neurodevelopment and neurodegeneration and the investigation of neuropeptide function. The examples discussed in this meeting report seek to illustrate the breadth and depth of presentations given on these recurring topics.

  2. Dairy Propionibacterium extends the mean lifespan of Caenorhabditis elegans via activation of the innate immune system.

    Science.gov (United States)

    Kwon, Gayeung; Lee, Jiyun; Lim, Young-Hee

    2016-08-17

    Dairy Propionibacterium freudenreichii is a candidate non-lactic acid probiotic. However, little information is available on the effect of P. freudenreichii on lifespan extension in humans. The aim of this study was to evaluate the effects of P. freudenreichii on lifespan extension and to elucidate the mechanism of P. freudenreichii-dependent lifespan extension in Caenorhabditis elegans. The results showed that P. freudenreichii significantly (p OP50, a standard food for the worm. Analysis of age-related biomarkers showed that P. freudenreichii retards ageing. Moreover, P. freudenreichii increased resistance against a human pathogen, Salmonella typhimurium, through the activation of skn-1, which is involved in pathogen resistance in C. elegans. Furthermore, P. freudenreichii-fed daf-16, jnk-1, skn-1 or daf-7 loss-of-function mutants showed an extended mean lifespan compared with E. coli OP50-fed worms. However, the increase in lifespan was not observed in pmk-1, sek-1, mek-1, dbl-1, daf-12 or daf-2 mutants, which suggests potential roles for these genes in P. freudenreichii-induced longevity in C. elegans. In conclusion, P. freudenreichii extends the lifespan of C. elegans via the p38 MAPK pathway involved in stress response and the TGF-β pathways associated with anti-inflammation processes in the immune system.

  3. Modulation of Caenorhabditis elegans immune response and modification of Shigella endotoxin upon interaction.

    Science.gov (United States)

    Kesika, Periyanaina; Prasanth, Mani Iyer; Balamurugan, Krishnaswamy

    2015-04-01

    To analyze the pathogenesis at both physiological and molecular level using the model organism, Caenorhabditis elegans at different developmental stages in response to Shigella spp. and its pathogen associated molecular patterns such as lipopolysaccharide. The solid plate and liquid culture-based infection assays revealed that Shigella spp. infects C. elegans and had an impact on the brood size and pharyngeal pumping rate. LPS of Shigella spp. was toxic to C. elegans. qPCR analysis revealed that host innate immune genes have been modulated upon Shigella spp. infections and its LPS challenges. Non-destructive analysis was performed to kinetically assess the alterations in LPS during interaction of Shigella spp. with C. elegans. The modulation of innate immune genes attributed the surrendering of host immune system to Shigella spp. by favoring the infection. LPS appeared to have a major role in Shigella-mediated pathogenesis and Shigella employs a tactic behavior of modifying its LPS content to escape from the recognition of host immune system.

  4. Genomic analysis of immune response against Vibrio cholerae hemolysin in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Surasri N Sahu

    Full Text Available Vibrio cholerae cytolysin (VCC is among the accessory V. cholerae virulence factors that may contribute to disease pathogenesis in humans. VCC, encoded by hlyA gene, belongs to the most common class of bacterial toxins, known as pore-forming toxins (PFTs. V. cholerae infects and kills Caenorhabditis elegans via cholerae toxin independent manner. VCC is required for the lethality, growth retardation and intestinal cell vacuolation during the infection. However, little is known about the host gene expression responses against VCC. To address this question we performed a microarray study in C. elegans exposed to V. cholerae strains with intact and deleted hlyA genes.Many of the VCC regulated genes identified, including C-type lectins, Prion-like (glutamine [Q]/asparagine [N]-rich-domain containing genes, genes regulated by insulin/IGF-1-mediated signaling (IIS pathway, were previously reported as mediators of innate immune response against other bacteria in C. elegans. Protective function of the subset of the genes up-regulated by VCC was confirmed using RNAi. By means of a machine learning algorithm called FastMEDUSA, we identified several putative VCC induced immune regulatory transcriptional factors and transcription factor binding motifs. Our results suggest that VCC is a major virulence factor, which induces a wide variety of immune response- related genes during V. cholerae infection in C. elegans.

  5. Multigenic natural variation underlies Caenorhabditis elegans olfactory preference for the bacterial pathogen Serratia marcescens.

    Science.gov (United States)

    Glater, Elizabeth E; Rockman, Matthew V; Bargmann, Cornelia I

    2014-02-19

    The nematode Caenorhabditis elegans can use olfaction to discriminate among different kinds of bacteria, its major food source. We asked how natural genetic variation contributes to choice behavior, focusing on differences in olfactory preference behavior between two wild-type C. elegans strains. The laboratory strain N2 strongly prefers the odor of Serratia marcescens, a soil bacterium that is pathogenic to C. elegans, to the odor of Escherichia coli, a commonly used laboratory food source. The divergent Hawaiian strain CB4856 has a weaker attraction to Serratia than the N2 strain, and this behavioral difference has a complex genetic basis. At least three quantitative trait loci (QTLs) from the CB4856 Hawaii strain (HW) with large effect sizes lead to reduced Serratia preference when introgressed into an N2 genetic background. These loci interact and have epistatic interactions with at least two antagonistic QTLs from HW that increase Serratia preference. The complex genetic architecture of this C. elegans trait is reminiscent of the architecture of mammalian metabolic and behavioral traits.

  6. Antimicrobial effectors in the nematode Caenorhabditis elegans: an outgroup to the Arthropoda.

    Science.gov (United States)

    Dierking, Katja; Yang, Wentao; Schulenburg, Hinrich

    2016-05-26

    Nematodes and arthropods likely form the taxon Ecdysozoa. Information on antimicrobial effectors from the model nematode Caenorhabditis elegans may thus shed light on the evolutionary origin of these defences in arthropods. This nematode species possesses an extensive armory of putative antimicrobial effector proteins, such as lysozymes, caenopores (or saposin-like proteins), defensin-like peptides, caenacins and neuropeptide-like proteins, in addition to the production of reactive oxygen species and autophagy. As C. elegans is a bacterivore that lives in microbe-rich environments, some of its effector peptides and proteins likely function in both digestion of bacterial food and pathogen elimination. In this review, we provide an overview of C. elegans immune effector proteins and mechanisms. We summarize the experimental evidence of their antimicrobial function and involvement in the response to pathogen infection. We further evaluate the microbe-induced expression of effector genes using WormExp, a recently established database for C. elegans gene expression analysis. We emphasize the need for further analysis at the protein level to demonstrate an antimicrobial activity of these molecules both in vitro and in vivoThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.

  7. Antioxidant and neuroprotective potential of chitooligomers in Caenorhabditis elegans exposed to Monocrotophos.

    Science.gov (United States)

    Nidheesh, T; Salim, Chinnu; Rajini, P S; Suresh, P V

    2016-01-01

    The objectives of this investigation were to establish the propensity of the chitooligomers (COS) to ameliorate neurodegeneration and oxidative stress in Caenorhabditis elegans induced by an organophosphorus insecticide, Monocrotophos (MCP). COS was prepared from α-chitosan by the enzymatic method using chitosanase and characterized by HPLC and electron spray ionization-TOF-(ESI-TOF)-MS. We exposed age synchronized L4 C. elegans worms (both wild type N2 and transgenic strain BZ555 (Pdat-1:GFP) to sublethal concentration of MCP (0.75mM) for 24h in the presence or absence of COS (0.2mM). The neuroprotective effect of COS was examined in N2 worms in terms of brood size, lifespan, egg laying, dopamine content, acetylcholinesterase and carboxylesterase activity and by direct visualization and quantification of degeneration of dopaminergic neurons in BZ555. Exposure to COS extended lifespan, normalized egg laying, increased brood size, decreased the dopaminergic neurodegeneration, increased the dopamine content and increased AChE and carboxylesterase activity in C. elegans treated with MCP. COS induced a significant decrease in reactive oxygen species and increased the reduced glutathione level as well as increased superoxide dismutase and catalase activity. Our findings demonstrate that COS significantly inhibits the dopaminergic neurodegeneration and associated physiological alterations induced by MCP in C. elegans by attenuating the oxidative stress as well.

  8. Expression of nicotinic acetylcholine receptor subunits from parasitic nematodes in Caenorhabditis elegans.

    Science.gov (United States)

    Sloan, Megan A; Reaves, Barbara J; Maclean, Mary J; Storey, Bob E; Wolstenholme, Adrian J

    2015-11-01

    The levamisole-sensitive nicotinic acetylcholine receptor present at nematode neuromuscular junctions is composed of multiple different subunits, with the exact composition varying between species. We tested the ability of two well-conserved nicotinic receptor subunits, UNC-38 and UNC-29, from Haemonchus contortus and Ascaris suum to rescue the levamisole-resistance and locomotion defects of Caenorhabditis elegans strains with null deletion mutations in the unc-38 and unc-29 genes. The parasite cDNAs were cloned downstream of the relevant C. elegans promoters and introduced into the mutant strains via biolistic transformation. The UNC-38 subunit of H. contortus was able to completely rescue both the locomotion defects and levamisole resistance of the null deletion mutant VC2937 (ok2896), but no C. elegans expressing the A. suum UNC-38 could be detected. The H. contortus UNC-29.1 subunit partially rescued the levamisole resistance of a C. elegans null mutation in unc-29 VC1944 (ok2450), but did cause increased motility in a thrashing assay. In contrast, only a single line of worms containing the A. suum UNC-29 subunit showed a partial rescue of levamisole resistance, with no effect on thrashing.

  9. Identification of lipid droplet structure-like/resident proteins in Caenorhabditis elegans.

    Science.gov (United States)

    Na, Huimin; Zhang, Peng; Chen, Yong; Zhu, Xiaotong; Liu, Yi; Liu, Yangli; Xie, Kang; Xu, Ningyi; Yang, Fuquan; Yu, Yong; Cichello, Simon; Mak, Ho Yi; Wang, Meng C; Zhang, Hong; Liu, Pingsheng

    2015-10-01

    The lipid droplet (LD) is a cellular organelle that stores neutral lipids in cells and has been linked with metabolic disorders. Caenorhabditis elegans has many characteristics which make it an excellent animal model for studying LDs. However, unlike in mammalian cells, no LD structure-like/resident proteins have been identified in C. elegans, which has limited the utility of this model for the study of lipid storage and metabolism. Herein based on three lines of evidence, we identified that MDT-28 and DHS-3 previously identified in C. elegans LD proteome were two LD structure-like/resident proteins. First, MDT-28 and DHS-3 were found to be the two most abundant LD proteins in the worm. Second, the proteins were specifically localized to LDs and we identified the domains responsible for this targeting in both proteins. Third and most importantly, the depletion of MDT-28 induced LD clustering while DHS-3 deletion reduced triacylglycerol content (TAG). We further characterized the proteins finding that MDT-28 was ubiquitously expressed in the intestine, muscle, hypodermis, and embryos, whereas DHS-3 was expressed mainly in intestinal cells. Together, these two LD structure-like/resident proteins provide a basis for future mechanistic studies into the dynamics and functions of LDs in C. elegans.

  10. Exercise in an electrotactic flow chamber ameliorates age-related degeneration in Caenorhabditis elegans

    Science.gov (United States)

    Chuang, Han-Sheng; Kuo, Wan-Jung; Lee, Chia-Lin; Chu, I-Hua; Chen, Chang-Shi

    2016-01-01

    Degeneration is a senescence process that occurs in all living organisms. Although tremendous efforts have been exerted to alleviate this degenerative tendency, minimal progress has been achieved to date. The nematode, Caenorhabditis elegans (C. elegans), which shares over 60% genetic similarities with humans, is a model animal that is commonly used in studies on genetics, neuroscience, and molecular gerontology. However, studying the effect of exercise on C. elegans is difficult because of its small size unlike larger animals. To this end, we fabricated a flow chamber, called “worm treadmill,” to drive worms to exercise through swimming. In the device, the worms were oriented by electrotaxis on demand. After the exercise treatment, the lifespan, lipofuscin, reproductive capacity, and locomotive power of the worms were analyzed. The wild-type and the Alzheimer’s disease model strains were utilized in the assessment. Although degeneration remained irreversible, both exercise-treated strains indicated an improved tendency compared with their control counterparts. Furthermore, low oxidative stress and lipofuscin accumulation were also observed among the exercise-treated worms. We conjecture that escalated antioxidant enzymes imparted the worms with an extra capacity to scavenge excessive oxidative stress from their bodies, which alleviated the adverse effects of degeneration. Our study highlights the significance of exercise in degeneration from the perspective of the simple life form, C. elegans. PMID:27305857

  11. Material properties of of Caenorhabditis elegans swimming at low Reynolds number

    CERN Document Server

    Sznitman, Josue; Krajacic, Predrag; Lamitina, Todd; Arratia, Paulo E

    2009-01-01

    Undulatory locomotion, as seen in the nematode \\emph{Caenorhabditis elegans}, is a common swimming gait of organisms in the low Reynolds number regime, where viscous forces are dominant. While the nematode's motility is expected to be a strong function of its material properties, measurements remain scarce. Here, the swimming behavior of \\emph{C.} \\emph{elegans} are investigated in experiments and in a simple model. Experiments reveal that nematodes swim in a periodic fashion and generate traveling waves which decay from head to tail. The model is able to capture the experiments' main features and is used to estimate the nematode's Young's modulus $E$ and tissue viscosity $\\eta$. For wild-type \\emph{C. elegans}, we find $E\\approx 3.77$ kPa and $\\eta \\approx-860$ Pa$\\cdot$s; values of $\\eta$ for live \\emph{C. elegans} are negative because the tissue is generating rather than dissipating energy. Results show that material properties are sensitive to changes in muscle functional properties, and are useful quanti...

  12. Pseudomonas aeruginosa killing of Caenorhabditis elegans used to identify P. aeruginosa virulence factors

    Science.gov (United States)

    Tan, Man-Wah; Rahme, Laurence G.; Sternberg, Jeffrey A.; Tompkins, Ronald G.; Ausubel, Frederick M.

    1999-01-01

    We reported recently that the human opportunistic pathogen Pseudomonas aeruginosa strain PA14 kills Caenorhabditis elegans and that many P. aeruginosa virulence factors (genes) required for maximum virulence in mouse pathogenicity are also required for maximum killing of C. elegans. Here we report that among eight P. aeruginosa PA14 TnphoA mutants isolated that exhibited reduced killing of C. elegans, at least five also exhibited reduced virulence in mice. Three of the TnphoA mutants corresponded to the known virulence-related genes lasR, gacA, and lemA. Three of the mutants corresponded to known genes (aefA from Escherichia coli, pstP from Azotobacter vinelandii, and mtrR from Neisseria gonorrhoeae) that had not been shown previously to play a role in pathogenesis, and two of the mutants contained TnphoA inserted into novel sequences. These data indicate that the killing of C. elegans by P. aeruginosa can be exploited to identify novel P. aeruginosa virulence factors important for mammalian pathogenesis. PMID:10051655

  13. Caenorhabditis elegans recognizes a bacterial quorum-sensing signal molecule through the AWCON neuron.

    Science.gov (United States)

    Werner, Kristen M; Perez, Lark J; Ghosh, Rajarshi; Semmelhack, Martin F; Bassler, Bonnie L

    2014-09-19

    In a process known as quorum sensing, bacteria use chemicals called autoinducers for cell-cell communication. Population-wide detection of autoinducers enables bacteria to orchestrate collective behaviors. In the animal kingdom detection of chemicals is vital for success in locating food, finding hosts, and avoiding predators. This behavior, termed chemotaxis, is especially well studied in the nematode Caenorhabditis elegans. Here we demonstrate that the Vibrio cholerae autoinducer (S)-3-hydroxytridecan-4-one, termed CAI-1, influences chemotaxis in C. elegans. C. elegans prefers V. cholerae that produces CAI-1 over a V. cholerae mutant defective for CAI-1 production. The position of the CAI-1 ketone moiety is the key feature driving CAI-1-directed nematode behavior. CAI-1 is detected by the C. elegans amphid sensory neuron AWC(ON). Laser ablation of the AWC(ON) cell, but not other amphid sensory neurons, abolished chemoattraction to CAI-1. These analyses define the structural features of a bacterial-produced signal and the nematode chemosensory neuron that permit cross-kingdom interaction.

  14. NeuCode Labeling in Nematodes: Proteomic and Phosphoproteomic Impact of Ascaroside Treatment in Caenorhabditis elegans*

    Science.gov (United States)

    Rhoads, Timothy W.; Prasad, Aman; Kwiecien, Nicholas W.; Merrill, Anna E.; Zawack, Kelson; Westphall, Michael S.; Schroeder, Frank C.; Kimble, Judith; Coon, Joshua J.

    2015-01-01

    The nematode Caenorhabditis elegans is an important model organism for biomedical research. We previously described NeuCode stable isotope labeling by amino acids in cell culture (SILAC), a method for accurate proteome quantification with potential for multiplexing beyond the limits of traditional stable isotope labeling by amino acids in cell culture. Here we apply NeuCode SILAC to profile the proteomic and phosphoproteomic response of C. elegans to two potent members of the ascaroside family of nematode pheromones. By consuming labeled E. coli as part of their diet, C. elegans nematodes quickly and easily incorporate the NeuCode heavy lysine isotopologues by the young adult stage. Using this approach, we report, at high confidence, one of the largest proteomic and phosphoproteomic data sets to date in C. elegans: 6596 proteins at a false discovery rate ≤ 1% and 6620 phosphorylation isoforms with localization probability ≥75%. Our data reveal a post-translational signature of pheromone sensing that includes many conserved proteins implicated in longevity and response to stress. PMID:26392051

  15. Analysis of Ascarosides from Caenorhabditis elegans Using Mass Spectrometry and NMR Spectroscopy

    Science.gov (United States)

    Zhang, Xinxing; Noguez, Jaime H.; Zhou, Yue; Butcher, Rebecca A.

    2014-01-01

    The nematode Caenorhabditis elegans secretes a family of water-soluble small molecules, known as the ascarosides, into its environment and uses these ascarosides in chemical communication. The ascarosides are derivatives of the 3,6-dideoxysugar ascarylose, modified with different fatty acid-derived side chains. C. elegans uses specific ascarosides, which are together known as the dauer pheromone, to trigger entry into the stress-resistant dauer larval stage. In addition, C. elegans uses specific ascarosides to control certain behaviors, including mating attraction, aggregation, and avoidance. Although in general the concentration of the ascarosides in the environment increases with population density, C. elegans can vary the types and amounts of ascarosides that it secretes depending on the culture conditions under which it has been grown and its developmental history. Here, we describe how to grow high-density worm cultures and the bacterial food for those cultures, as well as how to extract the culture medium to generate a crude pheromone extract. Then, we discuss how to analyze the types and amounts of ascarosides in that extract using mass spectrometry and NMR spectroscopy. PMID:24014355

  16. NeuCode Labeling in Nematodes: Proteomic and Phosphoproteomic Impact of Ascaroside Treatment in Caenorhabditis elegans.

    Science.gov (United States)

    Rhoads, Timothy W; Prasad, Aman; Kwiecien, Nicholas W; Merrill, Anna E; Zawack, Kelson; Westphall, Michael S; Schroeder, Frank C; Kimble, Judith; Coon, Joshua J

    2015-11-01

    The nematode Caenorhabditis elegans is an important model organism for biomedical research. We previously described NeuCode stable isotope labeling by amino acids in cell culture (SILAC), a method for accurate proteome quantification with potential for multiplexing beyond the limits of traditional stable isotope labeling by amino acids in cell culture. Here we apply NeuCode SILAC to profile the proteomic and phosphoproteomic response of C. elegans to two potent members of the ascaroside family of nematode pheromones. By consuming labeled E. coli as part of their diet, C. elegans nematodes quickly and easily incorporate the NeuCode heavy lysine isotopologues by the young adult stage. Using this approach, we report, at high confidence, one of the largest proteomic and phosphoproteomic data sets to date in C. elegans: 6596 proteins at a false discovery rate ≤ 1% and 6620 phosphorylation isoforms with localization probability ≥75%. Our data reveal a post-translational signature of pheromone sensing that includes many conserved proteins implicated in longevity and response to stress.

  17. Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria.

    Science.gov (United States)

    Antunes, Camila Azevedo; Clark, Laura; Wanuske, Marie-Therès; Hacker, Elena; Ott, Lisa; Simpson-Louredo, Liliane; de Luna, Maria das Gracas; Hirata, Raphael; Mattos-Guaraldi, Ana Luíza; Hodgkin, Jonathan; Burkovski, Andreas

    2016-01-01

    Caenorhabditis elegans is one of the major model systems in biology based on advantageous properties such as short life span, transparency, genetic tractability and ease of culture using an Escherichia coli diet. In its natural habitat, compost and rotting plant material, this nematode lives on bacteria. However, C. elegans is a predator of bacteria, but can also be infected by nematopathogenic coryneform bacteria such Microbacterium and Leucobacter species, which display intriguing and diverse modes of pathogenicity. Depending on the nematode pathogen, aggregates of worms, termed worm-stars, can be formed, or severe rectal swelling, so-called Dar formation, can be induced. Using the human and animal pathogens Corynebacterium diphtheriae and Corynebacterium ulcerans as well as the non-pathogenic species Corynebacterium glutamicum, we show that these coryneform bacteria can also induce star formation slowly in worms, as well as a severe tail-swelling phenotype. While C. glutamicum had a significant, but minor influence on survival of C. elegans, nematodes were killed after infection with C. diphtheriae and C. ulcerans. The two pathogenic species were avoided by the nematodes and induced aversive learning in C. elegans.

  18. Radiation-induced gene expression in the nematode Caenorhabditis elegans

    Science.gov (United States)

    Nelson, Gregory A.; Jones, Tamako A.; Chesnut, Aaron; Smith, Anna L.

    2002-01-01

    We used the nematode C. elegans to characterize the genotoxic and cytotoxic effects of ionizing radiation in a simple animal model emphasizing the unique effects of charged particle radiation. Here we demonstrate by RT-PCR differential display and whole genome microarray hybridization experiments that gamma rays, accelerated protons and iron ions at the same physical dose lead to unique transcription profiles. 599 of 17871 genes analyzed (3.4%) showed differential expression 3 hrs after exposure to 3 Gy of radiation. 193 were up-regulated, 406 were down-regulated and 90% were affected only by a single species of radiation. A novel statistical clustering technique identified the regulatory relationships between the radiation-modulated genes and showed that genes affected by each radiation species were associated with unique regulatory clusters. This suggests that independent homeostatic mechanisms are activated in response to radiation exposure as a function of track structure or ionization density.

  19. Radiation-induced gene expression in the nematode caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, G.A.; Jones, T.A.; Chesnut, A.; Smith, A.L. [Loma Linda Univ., CA (United States)

    2002-12-01

    We used the nematode C. elegans to characterize the genotoxic and cytotoxic effects of ionizing radiation in a simple animal model emphasizing the unique effects of charged particle radiation. Here we demonstrate by reverse transcription polymerase chain reaction (RT-PCR) differential display and whole genome microarray hybridization experiments that gamma rays, accelerated protons and iron ions at the same physical dose lead to unique transcription profiles. 599 of 17871 genes analyzed (3.4%) showed differential expression 3 hrs after exposure to 3 Gy of radiation. 193 were up-regulated, 406 were down-regulated and 90% were affected only by a single species of radiation. A novel statistical clustering technique identified the regulatory relationships between the radiation-modulated genes and showed that genes affected by each radiation species were associated with unique regulatory clusters. This suggests that independent homeostatic mechanisms are activated in response to radiation exposure as a function of track structure or ionization density. (author)

  20. Flow-Based Network Analysis of the Caenorhabditis elegans Connectome

    Science.gov (United States)

    Bacik, Karol A.; Schaub, Michael T.; Billeh, Yazan N.; Barahona, Mauricio

    2016-01-01

    We exploit flow propagation on the directed neuronal network of the nematode C. elegans to reveal dynamically relevant features of its connectome. We find flow-based groupings of neurons at different levels of granularity, which we relate to functional and anatomical constituents of its nervous system. A systematic in silico evaluation of the full set of single and double neuron ablations is used to identify deletions that induce the most severe disruptions of the multi-resolution flow structure. Such ablations are linked to functionally relevant neurons, and suggest potential candidates for further in vivo investigation. In addition, we use the directional patterns of incoming and outgoing network flows at all scales to identify flow profiles for the neurons in the connectome, without pre-imposing a priori categories. The four flow roles identified are linked to signal propagation motivated by biological input-response scenarios. PMID:27494178

  1. Crossover suppressors and balanced recessive lethals in Caenorhabditis elegans. [Nematode

    Energy Technology Data Exchange (ETDEWEB)

    Herman, R.K.

    1978-01-01

    Two dominant suppressors of crossing over have been identified following x-ray treatment of the small nematode C. elegans. They suppress crossing over in linkage group II (LGII) about 100-fold and 50-fold and are both tightly linked to LGII markers. One, called C1, segregates independently of all other linkage groups and is homozygous fertile. The other is a translocation involving LGII and X. The translocation also suppresses crossing over along the right half of X and is homozygous lethal. C1 has been used as a balancer of LGII recessive lethal and sterile mutations induced by EMS. The frequencies of occurrence of lethals and steriles were approximately equal. Fourteen mutations were assigned to complementation groups and mapped. They tended to map in the same region where LGII visibles are clustered.

  2. Malate and fumarate extend lifespan in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Clare B Edwards

    Full Text Available Malate, the tricarboxylic acid (TCA cycle metabolite, increased lifespan and thermotolerance in the nematode C. elegans. Malate can be synthesized from fumarate by the enzyme fumarase and further oxidized to oxaloacetate by malate dehydrogenase with the accompanying reduction of NAD. Addition of fumarate also extended lifespan, but succinate addition did not, although all three intermediates activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced oxidative stress. The glyoxylate shunt, an anabolic pathway linked to lifespan extension in C. elegans, reversibly converts isocitrate and acetyl-CoA to succinate, malate, and CoA. The increased longevity provided by malate addition did not occur in fumarase (fum-1, glyoxylate shunt (gei-7, succinate dehydrogenase flavoprotein (sdha-2, or soluble fumarate reductase F48E8.3 RNAi knockdown worms. Therefore, to increase lifespan, malate must be first converted to fumarate, then fumarate must be reduced to succinate by soluble fumarate reductase and the mitochondrial electron transport chain complex II. Reduction of fumarate to succinate is coupled with the oxidation of FADH2 to FAD. Lifespan extension induced by malate depended upon the longevity regulators DAF-16 and SIR-2.1. Malate supplementation did not extend the lifespan of long-lived eat-2 mutant worms, a model of dietary restriction. Malate and fumarate addition increased oxygen consumption, but decreased ATP levels and mitochondrial membrane potential suggesting a mild uncoupling of oxidative phosphorylation. Malate also increased NADPH, NAD, and the NAD/NADH ratio. Fumarate reduction, glyoxylate shunt activity, and mild mitochondrial uncoupling likely contribute to the lifespan extension induced by malate and fumarate by increasing the amount of oxidized NAD and FAD cofactors.

  3. The TRIM-NHL protein LIN-41 controls the onset of developmental plasticity in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Cristina Tocchini

    2014-08-01

    Full Text Available The mechanisms controlling cell fate determination and reprogramming are fundamental for development. A profound reprogramming, allowing the production of pluripotent cells in early embryos, takes place during the oocyte-to-embryo transition. To understand how the oocyte reprogramming potential is controlled, we sought Caenorhabditis elegans mutants in which embryonic transcription is initiated precociously in germ cells. This screen identified LIN-41, a TRIM-NHL protein and a component of the somatic heterochronic pathway, as a temporal regulator of pluripotency in the germline. We found that LIN-41 is expressed in the cytoplasm of developing oocytes, which, in lin-41 mutants, acquire pluripotent characteristics of embryonic cells and form teratomas. To understand LIN-41 function in the germline, we conducted structure-function studies. In contrast to other TRIM-NHL proteins, we found that LIN-41 is unlikely to function as an E3 ubiquitin ligase. Similar to other TRIM-NHL proteins, the somatic function of LIN-41 is thought to involve mRNA regulation. Surprisingly, we found that mutations predicted to disrupt the association of LIN-41 with mRNA, which otherwise compromise LIN-41 function in the heterochronic pathway in the soma, have only minor effects in the germline. Similarly, LIN-41-mediated repression of a key somatic mRNA target is dispensable for the germline function. Thus, LIN-41 appears to function in the germline and the soma via different molecular mechanisms. These studies provide the first insight into the mechanism inhibiting the onset of embryonic differentiation in developing oocytes, which is required to ensure a successful transition between generations.

  4. Context Specificity of Stress-activated Mitogen-activated Protein (MAP) Kinase Signaling: The Story as Told by Caenorhabditis elegans.

    Science.gov (United States)

    Andrusiak, Matthew G; Jin, Yishi

    2016-04-01

    Stress-associated p38 and JNK mitogen-activated protein (MAP) kinase signaling cascades trigger specific cellular responses and are involved in multiple disease states. At the root of MAP kinase signaling complexity is the differential use of common components on a context-specific basis. The roundwormCaenorhabditis eleganswas developed as a system to study genes required for development and nervous system function. The powerful genetics ofC. elegansin combination with molecular and cellular dissections has led to a greater understanding of how p38 and JNK signaling affects many biological processes under normal and stress conditions. This review focuses on the studies revealing context specificity of different stress-activated MAPK components inC. elegans.

  5. The interplay between protein L-isoaspartyl methyltransferase activity and insulin-like signaling to extend lifespan in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Shilpi Khare

    Full Text Available The protein L-isoaspartyl-O-methyltransferase functions to initiate the repair of isomerized aspartyl and asparaginyl residues that spontaneously accumulate with age in a variety of organisms. Caenorhabditis elegans nematodes lacking the pcm-1 gene encoding this enzyme display a normal lifespan and phenotype under standard laboratory growth conditions. However, significant defects in development, egg laying, dauer survival, and autophagy have been observed in pcm-1 mutant nematodes when deprived of food and when exposed to oxidative stress. Interestingly, overexpression of this repair enzyme in both Drosophila and C. elegans extends adult lifespan under thermal stress. In this work, we show the involvement of the insulin/insulin-like growth factor-1 signaling (IIS pathway in PCM-1-dependent lifespan extension in C. elegans. We demonstrate that reducing the levels of the DAF-16 downstream transcriptional effector of the IIS pathway by RNA interference reduces the lifespan extension resulting from PCM-1 overexpression. Using quantitative real-time PCR analysis, we show the up-regulation of DAF-16-dependent stress response genes in the PCM-1 overexpressor animals compared to wild-type and pcm-1 mutant nematodes under mild thermal stress conditions. Additionally, similar to other long-lived C. elegans mutants in the IIS pathway, including daf-2 and age-1 mutants, PCM-1 overexpressor adult animals display increased resistance to severe thermal stress, whereas pcm-1 mutant animals survive less long under these conditions. Although we observe a higher accumulation of damaged proteins in pcm-1 mutant nematodes, the basal level of isoaspartyl residues detected in wild-type animals was not reduced by PCM-1 overexpression. Our results support a signaling role for the protein L-isoaspartyl methyltransferase in lifespan extension that involves the IIS pathway, but that may be independent of its function in overall protein repair.

  6. Anti-inflammatory Lactobacillus rhamnosus CNCM I-3690 strain protects against oxidative stress and increases lifespan in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Gianfranco Grompone

    Full Text Available Numerous studies have shown that resistance to oxidative stress is crucial to stay healthy and to reduce the adverse effects of aging. Accordingly, nutritional interventions using antioxidant food-grade compounds or food products are currently an interesting option to help improve health and quality of life in the elderly. Live lactic acid bacteria (LAB administered in food, such as probiotics, may be good antioxidant candidates. Nevertheless, information about LAB-induced oxidative stress protection is scarce. To identify and characterize new potential antioxidant probiotic strains, we have developed a new functional screening method using the nematode Caenorhabditis elegans as host. C. elegans were fed on different LAB strains (78 in total and nematode viability was assessed after oxidative stress (3 mM and 5 mM H(2O(2. One strain, identified as Lactobacillus rhamnosus CNCM I-3690, protected worms by increasing their viability by 30% and, also, increased average worm lifespan by 20%. Moreover, transcriptomic analysis of C. elegans fed with this strain showed that increased lifespan is correlated with differential expression of the DAF-16/insulin-like pathway, which is highly conserved in humans. This strain also had a clear anti-inflammatory profile when co-cultured with HT-29 cells, stimulated by pro-inflammatory cytokines, and co-culture systems with HT-29 cells and DC in the presence of LPS. Finally, this Lactobacillus strain reduced inflammation in a murine model of colitis. This work suggests that C. elegans is a fast, predictive and convenient screening tool to identify new potential antioxidant probiotic strains for subsequent use in humans.

  7. The alkaloid compound harmane increases the lifespan of Caenorhabditis elegans during bacterial infection, by modulating the nematode's innate immune response

    DEFF Research Database (Denmark)

    Jakobsen, Henrik; Bojer, Martin Saxtorph; Marinus, Martin G.

    2013-01-01

    The nematode Caenorhabditis elegans has in recent years been proven to be a powerful in vivo model for testing antimicrobial compounds. We report here that the alkaloid compound Harmane (2-methyl-β-carboline) increases the lifespan of nematodes infected with a human pathogen, the Shiga toxin...

  8. Identifying Novel Helix-Loop-Helix Genes in "Caenorhabditis elegans" through a Classroom Demonstration of Functional Genomics

    Science.gov (United States)

    Griffin, Vernetta; McMiller, Tracee; Jones, Erika; Johnson, Casonya M.

    2003-01-01

    A 14-week, undergraduate-level Genetics and Population Biology course at Morgan State University was modified to include a demonstration of functional genomics in the research laboratory. Students performed a rudimentary sequence analysis of the "Caenorhabditis elegans" genome and further characterized three sequences that were predicted to encode…

  9. Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin

    Science.gov (United States)

    Henze, Andrea; Homann, Thomas; Rohn, Isabelle; Aschner, Michael; Link, Christopher D.; Kleuser, Burkhard; Schweigert, Florian J.; Schwerdtle, Tanja; Bornhorst, Julia

    2016-11-01

    The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization – time of flight – mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.

  10. Spatiotemporal Feedback and Network Structure Drive and Encode Caenorhabditis elegans Locomotion

    Science.gov (United States)

    Kunert, James M.; Proctor, Joshua L.; Kutz, J. Nathan

    2017-01-01

    Using a computational model of the Caenorhabditis elegans connectome dynamics, we show that proprioceptive feedback is necessary for sustained dynamic responses to external input. This is consistent with the lack of biophysical evidence for a central pattern generator, and recent experimental evidence that proprioception drives locomotion. The low-dimensional functional response of the Caenorhabditis elegans network of neurons to proprioception-like feedback is optimized by input of specific spatial wavelengths which correspond to the spatial scale of real body shape dynamics. Furthermore, we find that the motor subcircuit of the network is responsible for regulating this response, in agreement with experimental expectations. To explore how the connectomic dynamics produces the observed two-mode, oscillatory limit cycle behavior from a static fixed point, we probe the fixed point’s low-dimensional structure using Dynamic Mode Decomposition. This reveals that the nonlinear network dynamics encode six clusters of dynamic modes, with timescales spanning three orders of magnitude. Two of these six dynamic mode clusters correspond to previously-discovered behavioral modes related to locomotion. These dynamic modes and their timescales are encoded by the network’s degree distribution and specific connectivity. This suggests that behavioral dynamics are partially encoded within the connectome itself, the connectivity of which facilitates proprioceptive control. PMID:28076347

  11. microRNAs control of in vivo toxicity from graphene oxide in Caenorhabditis elegans.

    Science.gov (United States)

    Wu, Qiuli; Zhao, Yunli; Zhao, Gui; Wang, Dayong

    2014-10-01

    The molecular basis for in vivo graphene oxide (GO) toxicity is still largely unclear. We here used Caenorhabditis elegans to investigate the microRNAs (miRNAs) control of GO toxicity. With the aid of SOLiD sequencing, we identified 23 up-regulated and 8 down-regulated miRNAs in GO-exposed nematodes. Gene ontology and KEGG pathway database analysis implied that these identified miRNAs might be involved in control of many biological processes, and some of them suggest the possible new functions of GO. Functions of the identified miRNAs in regulating the GO toxicity on lifespan were confirmed in the available miRNAs mutants. Moreover, we provide the evidence to raise a hypothesis that GO may reduce lifespan through influencing the functions of insulin/IGF signaling, TOR signaling, and germline signaling pathways controlled by miRNAs. Our results will be helpful for understanding the molecular basis for GO toxicity, and finding clues for useful surface modifications to reduce GO toxicity. From the clinical editor: In this study, toxicity of graphene oxide is studied in a Caenorhabditis elegans model via microRNA analysis. The authors report that multiple important pathways are influenced by GO and raise a hypothesis that GO may reduce lifespan through influencing the functions of insulin/IGF signaling, TOR signaling, and germline signaling pathways.

  12. Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories

    Directory of Open Access Journals (Sweden)

    Liberta Nika

    2016-07-01

    Full Text Available Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection.

  13. Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories.

    Science.gov (United States)

    Nika, Liberta; Gibson, Taylor; Konkus, Rebecca; Karp, Xantha

    2016-07-07

    Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection.

  14. Fluorescent Beads Are a Versatile Tool for Staging Caenorhabditis elegans in Different Life Histories

    Science.gov (United States)

    Nika, Liberta; Gibson, Taylor; Konkus, Rebecca; Karp, Xantha

    2016-01-01

    Precise staging of Caenorhabditis elegans is essential for developmental studies in different environmental conditions. In favorable conditions, larvae develop continuously through four larval stages separated by molting periods. Distinguishing molting from intermolt larvae has been achieved using transgenes with molting reporters, therefore requiring strain constructions, or careful observation of individuals for pharyngeal pumping or behavioral quiescence. In unfavorable conditions, larvae can enter the stress-resistant and developmentally arrested dauer larva stage. Identifying dauer larvae has been based on their ability to withstand detergent selection, precluding identification of recovering animals or of mutants with defects in dauer morphogenesis. Here, we describe a simple method to distinguish molting larvae or dauer larvae from intermolt larvae that bypasses the limitations of current methods. Fluorescent latex beads are mixed with the bacterial food source and ingested by intermolt larvae and adults. Molting and dauer larvae do not feed, and therefore lack beads in their digestive tract. The presence of beads can be determined using a dissecting microscope at magnifications as low as 100 ×, or by using a wormsorter for high-throughput experiments. We find that continuously developing bead-lacking larvae display hallmarks of molting, including expression of the mlt-10::gfp molting marker and a lack of pharyngeal pumping. Furthermore, wild-type and mutant dauer larvae produced by any of three common methods are accurately identified by a lack of beads. Importantly, this method is effective in SDS-sensitive mutant backgrounds and can identify recovering dauer larvae, a stage for which there is no other method of positive selection. PMID:27172224

  15. The Application of Image Processing in the Experiment of Caenorhabditis Elegans%图像处理在线虫实验中的应用

    Institute of Scientific and Technical Information of China (English)

    陈维洋; 李伟伟; 裴佳伦

    2016-01-01

    在科学实验中,秀丽隐杆线虫是一种广泛使用的模式生物。随着生物图像处理技术的发展,在以线虫为模式生物的研究中图像处理的应用越来越多。图像处理用于从实验过程中拍摄得到的图像或视频中自动识别出线虫,并自动定量线虫的大小、形状等表型。有的实验中还通过图像处理技术对实验视频中的线虫进行动态跟踪,进而分析线虫在各种刺激下的应激反应。一些研究中还通过图像处理技术来测量荧光表达模式以及构建高分辨率的线虫细胞三维数字图谱等。对使用线虫作为模式生物的实验中图像处理技术的应用作了综述。%Caenorhabditis elegans is a widely used model organism.With the development of bio-image processing,the number of application of processing images of Caenorhabditis elegans is becoming more and more.The applications range from automatically detecting the position of worms and quantifying the phenotypes( such as body size and shape) to the analysis of behavioral phenotypes of Caenorhabditis elegans.Some studies also quantified the gene expression profiles by detecting the fluorescent signal from experimental images and built 3D digital nuclear atlas of Caenorhabditis elegans at single-cell resolution. Finally,major applications of image processing in the experiment of Caenorhabditis elegans are reviewed.

  16. Absorption and Biodistribution of Nanoparticles in Mouse, Caenorhabditis elegans, Arabidopsis thaliana and Nicotina bethamiana

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    Al Awwad, Nasir

    Nanotechnology is the arrangement of materials, and devices which permit technology to operate in nanometer-sized objects. Some of the potential applications of these nanomaterials include light harvesting for solar cells, light emitting enhancer for LEDs, cosmetics, and nanocarriers for pesticide applications and drug delivery. The impact of nanomaterials on the environment is a concern. The Lam laboratory has developed a novel nanocarrier system for the delivery of hydrophobic drugs or imaging agents against tumors. This nanocarriers are based on polyethylene glycol-cholic acid cluster telodendrimers which can self-assemble to form micellar structure. Here we report on the ability of these nanocarriers to cross the blood brain barrier (BBB) in murine model, and the GI absorption of the nanocarrier in Caenorhabditis elegans models. In addition, we also studied the uptake of the nanocarriers by Arabidopsis Thaliana seedlings and Nicotina bethamiana leaves, Application of three different biological organisms were used, one mammalian, one invertebrate, and one plant. Drug delivery to the central nervous system is not easy as compared to other body organs due to the presence of the BBB. It is essential that any delivery system to the central nervous system (CNS) needs to be efficient and non-toxic. Adenosine receptor agonists have been reported to be able to modulate the permeability of the BBB to macromolecules. Here, we studied the effect of 5'-(NEthylcarboxamido) (NECA), an adenosine receptor agonist, on the penetration of both non-crosslinked micelle (NCM) and disulfide cross-linked micelle (DCM) through the blood brain barrier into the brain parenchyma. We found that NECA given at 5.3 mg/kg intravenously, was able to facilitate the delivery of fluorescentlabeled NCM, DCM and polyvinyl alcohol (PVA) based nanocarriers to organs or blood vessels expressing adenosine receptors, which also include the brain. After ingestion, both DCM and NCM were localized inside the

  17. Examining mechanism of toxicity of copper oxide nanoparticles to Saccharomyces cerevisiae and Caenorhabditis elegans

    Science.gov (United States)

    Mashock, Michael J.

    Copper oxide nanoparticles (CuO NPs) are an up and coming technology increasingly being used in industrial and consumer applications and thus may pose risk to humans and the environment. In the present study, the toxic effects of CuO NPs were studied with two model organisms Saccharomyces cerevisiae and Caenorhabditis elegans. The role of released Cu ions during dissolution of CuO NPs in growth media were studied with freshly suspended, aged NPs, and the released Cu 2+ fraction. Exposures to the different Cu treatments showed significant inhibition of S. cerevisiae cellular metabolic activity. Inhibition from the NPs was inversely proportional to size and was not fully explained by the released Cu ions. S. cerevisiae cultures grown under respiring conditions demonstrated greater metabolic sensitivity when exposed to CuO NPs compared to cultures undergoing fermentation. The cellular response to both CuO NPs and released Cu ions on gene expression was analyzed via microarray analysis after an acute exposure. It was observed that both copper exposures resulted in an increase in carbohydrate storage, a decrease in protein production, protein misfolding, increased membrane permeability, and cell cycle arrest. Cells exposed to NPs up-regulated genes related to oxidative phosphorylation but also may be inducing cell cycle arrest by a different mechanism than that observed with released Cu ions. The effect of CuO NPs on C. elegans was examined by using several toxicological endpoints. The CuO NPs displayed a more inhibitory effect, compared to copper sulfate, on nematode reproduction, feeding, and development. We investigated the effects of copper oxide nanoparticles and copper sulfate on neuronal health, a known tissue vulnerable to heavy metal toxicity. In transgenic C. eleganswith neurons expressing a green fluorescent protein reporter, neuronal degeneration was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, nematode

  18. Caenorhabditis elegans glutamylating enzymes function redundantly in male mating.

    Science.gov (United States)

    Chawla, Daniel G; Shah, Ruchi V; Barth, Zachary K; Lee, Jessica D; Badecker, Katherine E; Naik, Anar; Brewster, Megan M; Salmon, Timothy P; Peel, Nina

    2016-09-15

    Microtubule glutamylation is an important modulator of microtubule function and has been implicated in the regulation of centriole stability, neuronal outgrowth and cilia motility. Glutamylation of the microtubules is catalyzed by a family of tubulin tyrosine ligase-like (TTLL) enzymes. Analysis of individual TTLL enzymes has led to an understanding of their specific functions, but how activities of the TTLL enzymes are coordinated to spatially and temporally regulate glutamylation remains relatively unexplored. We have undertaken an analysis of the glutamylating TTLL enzymes in C. elegans We find that although all five TTLL enzymes are expressed in the embryo and adult worm, loss of individual enzymes does not perturb microtubule function in embryonic cell divisions. Moreover, normal dye-filling, osmotic avoidance and male mating behavior indicate the presence of functional amphid cilia and male-specific neurons. A ttll-4(tm3310); ttll-11(tm4059); ttll-5(tm3360) triple mutant, however, shows reduced male mating efficiency due to a defect in the response step, suggesting that these three enzymes function redundantly, and that glutamylation is required for proper function of the male-specific neurons.

  19. A point mutation in the extracellular domain activates LET-23, the Caenorhabditis elegans epidermal growth factor receptor homolog.

    Science.gov (United States)

    Katz, W S; Lesa, G M; Yannoukakos, D; Clandinin, T R; Schlessinger, J; Sternberg, P W

    1996-01-01

    The let-23 gene encodes a Caenorhabditis elegans homolog of the epidermal growth factor receptor (EGFR) necessary for vulval development. We have characterized a mutation of let-23 that activates the receptor and downstream signal transduction, leading to excess vulval differentiation. This mutation alters a conserved cysteine residue in the extracellular domain and is the first such point mutation in the EGFR subfamily of tyrosine kinases. Mutation of a different cysteine in the same subdomain causes a strong loss-of-function phenotype, suggesting that cysteines in this region are important for function and nonequivalent. Vulval precursor cells can generate either of two subsets of vulval cells (distinct fates) in response to sa62 activity. The fates produced depended on the copy number of the mutation, suggesting that quantitative differences in receptor activity influence the decision between these two fates. PMID:8552080

  20. PUF-8 Functions Redundantly with GLD-1 to Promote the Meiotic Progression of Spermatocytes in Caenorhabditis elegans.

    Science.gov (United States)

    Priti, Agarwal; Subramaniam, Kuppuswamy

    2015-06-10

    Successful meiotic progression of germ cells is crucial for gametogenesis. Defects in this process affect proper genetic transmission and sometimes lead to tumor formation in the germline. In Caenorhabditis elegans, the RNA-binding protein GLD-1 is essential for the meiotic development of oocytes. However, its role during spermatogenesis has not been understood. Here, we show that GLD-1 functions redundantly with the PUF family protein PUF-8 to ensure proper meiotic development of spermatocytes. When grown at 20°-the standard laboratory temperature for C. elegans growth-primary spermatocytes in both gld-1 and puf-8 single-mutant males and hermaphrodites complete the meiotic divisions normally. By contrast, some of the gld-1; puf-8 double-mutant spermatocytes exit meiosis and form germ cell tumors in both sexes. During larval development, gld-1; puf-8 double-mutant germ cells begin to express the meiotic marker HIM-3, lose P granules, and form the sperm-specific membranous organelle, which are characteristics of developing spermatocytes. However, some of these cells quickly lose HIM-3 and form germ cell tumors that lack membranous organelle but contain P granules. Mutations that block meiotic progression at late pachytene or diakinetic stage fail to arrest the tumorigenesis, suggesting that the gld-1; puf-8 double-mutant spermatocytes exit meiosis prior to the completion of pachytene. Together, results presented here uncover a novel function for gld-1 in the meiotic development of spermatocytes in both hermaphrodites and males.

  1. The atypical calpains: evolutionary analyses and roles in Caenorhabditis elegans cellular degeneration.

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    Peter I Joyce

    Full Text Available The calpains are physiologically important Ca(2+-activated regulatory proteases, which are divided into typical or atypical sub-families based on constituent domains. Both sub-families are present in mammals, but our understanding of calpain function is based primarily on typical sub-family members. Here, we take advantage of the model organism Caenorhabditis elegans, which expresses only atypical calpains, to extend our knowledge of the phylogenetic evolution and function of calpains. We provide evidence that a typical human calpain protein with a penta EF hand, detected using custom profile hidden Markov models, is conserved in ancient metazoans and a divergent clade. These analyses also provide evidence for the lineage-specific loss of typical calpain genes in C. elegans and Ciona, and they reveal that many calpain-like genes lack an intact catalytic triad. Given the association between the dysregulation of typical calpains and human degenerative pathologies, we explored the phenotypes, expression profiles, and consequences of inappropriate reduction or activation of C. elegans atypical calpains. These studies show that the atypical calpain gene, clp-1, contributes to muscle degeneration and reveal that clp-1 activity is sensitive to genetic manipulation of [Ca(2+](i. We show that CLP-1 localizes to sarcomeric sub-structures, but is excluded from dense bodies (Z-disks. We find that the muscle degeneration observed in a C. elegans model of dystrophin-based muscular dystrophy can be suppressed by clp-1 inactivation and that nemadipine-A inhibition of the EGL-19 calcium channel reveals that Ca(2+ dysfunction underlies the C. elegans MyoD model of myopathy. Taken together, our analyses highlight the roles of calcium dysregulation and CLP-1 in muscle myopathies and suggest that the atypical calpains could retain conserved roles in myofilament turnover.

  2. The atypical calpains: evolutionary analyses and roles in Caenorhabditis elegans cellular degeneration.

    Science.gov (United States)

    Joyce, Peter I; Satija, Rahul; Chen, Maozi; Kuwabara, Patricia E

    2012-01-01

    The calpains are physiologically important Ca(2+)-activated regulatory proteases, which are divided into typical or atypical sub-families based on constituent domains. Both sub-families are present in mammals, but our understanding of calpain function is based primarily on typical sub-family members. Here, we take advantage of the model organism Caenorhabditis elegans, which expresses only atypical calpains, to extend our knowledge of the phylogenetic evolution and function of calpains. We provide evidence that a typical human calpain protein with a penta EF hand, detected using custom profile hidden Markov models, is conserved in ancient metazoans and a divergent clade. These analyses also provide evidence for the lineage-specific loss of typical calpain genes in C. elegans and Ciona, and they reveal that many calpain-like genes lack an intact catalytic triad. Given the association between the dysregulation of typical calpains and human degenerative pathologies, we explored the phenotypes, expression profiles, and consequences of inappropriate reduction or activation of C. elegans atypical calpains. These studies show that the atypical calpain gene, clp-1, contributes to muscle degeneration and reveal that clp-1 activity is sensitive to genetic manipulation of [Ca(2+)](i). We show that CLP-1 localizes to sarcomeric sub-structures, but is excluded from dense bodies (Z-disks). We find that the muscle degeneration observed in a C. elegans model of dystrophin-based muscular dystrophy can be suppressed by clp-1 inactivation and that nemadipine-A inhibition of the EGL-19 calcium channel reveals that Ca(2+) dysfunction underlies the C. elegans MyoD model of myopathy. Taken together, our analyses highlight the roles of calcium dysregulation and CLP-1 in muscle myopathies and suggest that the atypical calpains could retain conserved roles in myofilament turnover.

  3. Trans-cellular introduction of HIV-1 protein Nef induces pathogenic response in Caenorhabditis elegans.

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    Aamir Nazir

    Full Text Available BACKGROUND: Caenorhabditis elegans has emerged as a very powerful model for studying the host pathogen interactions. Despite the absence of a naturally occurring viral infection for C. elegans, the model is now being exploited experimentally to study the basic aspects of virus-host interplay. The data generated from recent studies suggests that the virus that infects mammalian cells does infect, replicate and accumulate in C. elegans. METHODOLOGY/PRINCIPAL FINDINGS: We took advantage of the easy-to-achieve protein introduction in C. elegans and employing the methodology, we administered HIV-1 protein Nef into live worms. Nef is known to be an important protein for exacerbating HIV-1 pathogenesis in host by enhancing viral replication. The deletion of nef from the viral genome has been reported to inhibit its replication in the host, thereby leading to delayed pathogenesis. Our studies, employing Nef introduction into C. elegans, led to creation of an in-vivo model that allowed us to study, whether or not, the protein induces effect in the whole organism. We observed a marked lipodystrophy, effect on neuromuscular function, impaired fertility and reduced longevity in the worms exposed to Nef. The observed effects resemble to those observed in Nef transgenic mice and most interestingly the effects also relate to some of the pathogenic aspects exhibited by human AIDS patients. CONCLUSIONS/SIGNIFICANCE: Our studies underline the importance of this in vivo model for studying the interactions of Nef with host proteins, which could further be used for identifying possible inhibitors of such interactions.

  4. Caenorhabditis elegans glutamate transporters influence synaptic function and behavior at sites distant from the synapse.

    Science.gov (United States)

    Mano, Itzhak; Straud, Sarah; Driscoll, Monica

    2007-11-23

    To ensure precise neurotransmission and prevent neurotoxic accumulation, l-glutamate (Glu), the major excitatory neurotransmitter in the brain, is cleared from the synapse by glutamate transporters (GluTs). The molecular components of Glu synapses are highly conserved between Caenorhabditis elegans and mammals, yet the absence of synaptic insulation in C. elegans raises fundamental questions about Glu clearance strategies in the nematode nervous system. To gain insight into how Glu clearance is accomplished and how GluTs impact neurotransmission, we probed expression and function of all 6 GluTs found in the C. elegans genome. Disruption of each GluT impacts multiple Glu-dependent behaviors, with GluT combinations commonly increasing the severity of behavioral deficits. Interestingly, the sole GluT that we find expressed in neurons is localized predominantly in presynaptic neurons, in contrast to the postsynaptic concentration of neuronal GluTs typical in mammals. Moreover, 3 of the 6 GluT genes appear strongly expressed on the capillary excretory canal cell, where they affect Glu-dependent behaviors from positions distal to glutamatergic circuits. Indeed, our focused study of GLT-3, one of the distally expressed GluTs, shows that despite this distance, GLT-3 function can balance the activity mediated by synaptic release and synaptic receptors. The effects of distal GluTs on glutamatergic circuits support that Glu diffusion outside the vicinity of the synapse is a critical factor in C. elegans neurotransmission. Together with the presynaptic localization of neuronal GluTs, these observations suggest an unusual strategy for Glu clearance in C. elegans.

  5. A proteomic view of Caenorhabditis elegans caused by short-term hypoxic stress

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    Wu Yonghong

    2010-09-01

    Full Text Available Abstract Background The nematode Caenorhabditis elegans is both sensitive and tolerant to hypoxic stress, particularly when the evolutionarily conserved hypoxia response pathway HIF-1/EGL-9/VHL is involved. Hypoxia-induced changes in the expression of a number of genes have been analyzed using whole genome microarrays in C. elegans, but the changes at the protein level in response to hypoxic stress still remain unclear. Results Here, we utilized a quantitative proteomic approach to evaluate changes in the expression patterns of proteins during the early response to hypoxia in C. elegans. Two-dimensional difference gel electrophoresis (2D-DIGE was used to compare the proteomic maps of wild type C. elegans strain N2 under a 4-h hypoxia treatment (0.2% oxygen and under normoxia (control. A subsequent analysis by MALDI-TOF-TOF-MS revealed nineteen protein spots that were differentially expressed. Nine of the protein spots were significantly upregulated, and ten were downregulated upon hypoxic stress. Three of the upregulated proteins were involved in cytoskeletal function (LEV-11, MLC-1, ACT-4, while another three upregulated (ATP-2, ATP-5, VHA-8 were ATP synthases functionally related to energy metabolism. Four ribosomal proteins (RPL-7, RPL-8, RPL-21, RPS-8 were downregulated, indicating a decrease in the level of protein translation upon hypoxic stress. The overexpression of tropomyosin (LEV-11 was further validated by Western blot. In addition, the mutant strain of lev-11(x12 also showed a hypoxia-sensitive phenotype in subsequent analyses, confirming the proteomic findings. Conclusions Taken together, our data suggest that altered protein expression, structural protein remodeling, and the reduction of translation might play important roles in the early response to oxygen deprivation in C. elegans, and this information will help broaden our knowledge on the mechanism of hypoxia response.

  6. Insight into transcription factor gene duplication from Caenorhabditis elegans Promoterome-driven expression patterns

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    Vidal Marc

    2007-01-01

    Full Text Available Abstract Background The C. elegans Promoterome is a powerful resource for revealing the regulatory mechanisms by which transcription is controlled pan-genomically. Transcription factors will form the core of any systems biology model of genome control and therefore the promoter activity of Promoterome inserts for C. elegans transcription factor genes was examined, in vivo, with a reporter gene approach. Results Transgenic C. elegans strains were generated for 366 transcription factor promoter/gfp reporter gene fusions. GFP distributions were determined, and then summarized with reference to developmental stage and cell type. Reliability of these data was demonstrated by comparison to previously described gene product distributions. A detailed consideration of the results for one C. elegans transcription factor gene family, the Six family, comprising ceh-32, ceh-33, ceh-34 and unc-39 illustrates the value of these analyses. The high proportion of Promoterome reporter fusions that drove GFP expression, compared to previous studies, led to the hypothesis that transcription factor genes might be involved in local gene duplication events less frequently than other genes. Comparison of transcription factor genes of C. elegans and Caenorhabditis briggsae was therefore carried out and revealed very few examples of functional gene duplication since the divergence of these species for most, but not all, transcription factor gene families. Conclusion Examining reporter expression patterns for hundreds of promoters informs, and thereby improves, interpretation of this data type. Genes encoding transcription factors involved in intrinsic developmental control processes appear acutely sensitive to changes in gene dosage through local gene duplication, on an evolutionary time scale.

  7. Association with Soil Bacteria Enhances p38-Dependent Infection Resistance in Caenorhabditis elegans

    Science.gov (United States)

    Montalvo-Katz, Sirena; Huang, Hao; Appel, Michael David; Berg, Maureen

    2013-01-01

    The importance of our inner microbial communities for proper immune responses against invading pathogens is now well accepted, but the mechanisms underlying this protection are largely unknown. In this study, we used Caenorhabditis elegans to investigate such mechanisms. Since very little is known about the microbes interacting with C. elegans in its natural environment, we began by taking the first steps to characterize the C. elegans microbiota. We established a natural-like environment in which initially germfree, wild-type larvae were grown on enriched soil. Bacterial members of the adult C. elegans microbiota were isolated by culture and identified using 16S rRNA gene sequencing. Using pure cultures of bacterial isolates as food, we identified two, Bacillus megaterium and Pseudomonas mendocina, that enhanced resistance to a subsequent infection with the Gram-negative pathogen Pseudomonas aeruginosa. Whereas protection by B. megaterium was linked to impaired egg laying, corresponding to a known trade-off between fecundity and resistance, the mechanism underlying protection conferred by P. mendocina depended on weak induction of immune genes regulated by the p38 MAPK pathway. Disruption of the p38 ortholog, pmk-1, abolished protection. P. mendocina enhanced resistance to P. aeruginosa but not to the Gram-positive pathogen Enterococcus faecalis. Furthermore, protection from P. aeruginosa was similarly induced by a P. aeruginosa gacA mutant with attenuated virulence but not by a different C. elegans-associated Pseudomonas sp. isolate. Our results support a pivotal role for the conserved p38 pathway in microbiota-initiated immune protection and suggest that similarity between microbiota members and pathogens may play a role in such protection. PMID:23230286

  8. Effects of lithium on growth, maturation, reproduction and gene expression in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Inokuchi, Ayako; Yamamoto, Ryoko; Morita, Fumiyo; Takumi, Shota; Matsusaki, Hiromi; Ishibashi, Hiroshi; Tominaga, Nobuaki; Arizono, Koji

    2015-09-01

    Lithium (Li) has been widely used to treat bipolar disorder, and industrial use of Li has been increasing; thus, environmental pollution and ecological impacts of Li have become a concern. This study was conducted to clarify the potential biological effects of LiCl and Li(2)CO(3) on a nematode, Caenorhabditis elegans as a model system for evaluating soil contaminated with Li. Exposure of C. elegans to LiCl and Li(2)CO(3) decreased growth/maturation and reproduction. The lowest observed effect concentrations for growth, maturation and reproduction were 1250, 313 and 10 000 µm, respectively, for LiCl and 750, 750 and 3000 µm, respectively, for Li(2)CO(3). We also investigated the physiological function of LiCl and LiCO(3) in C. elegans using DNA microarray analysis as an eco-toxicogenomic approach. Among approximately 300 unique genes, including metabolic genes, the exposure to 78 µm LiCl downregulated the expression of 36 cytochrome P450, 16 ABC transporter, 10 glutathione S-transferase, 16 lipid metabolism and two vitellogenin genes. On the other hand, exposure to 375 µm Li(2)CO(3) downregulated the expression of 11 cytochrome P450, 13 ABC transporter, 13 lipid metabolism and one vitellogenin genes. No gene was upregulated by LiCl or Li(2)CO(3). These results suggest that LiCl and Li(2)CO(3) potentially affect the biological and physiological function in C. elegans associated with alteration of the gene expression such as metabolic genes. Our data also provide experimental support for the utility of toxicogenomics by integrating gene expression profiling into a toxicological study of an environmentally important organism such as C. elegans.

  9. TRY-5 is a sperm-activating protease in Caenorhabditis elegans seminal fluid.

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    Joseph R Smith

    2011-11-01

    Full Text Available Seminal fluid proteins have been shown to play important roles in male reproductive success, but the mechanisms for this regulation remain largely unknown. In Caenorhabditis elegans, sperm differentiate from immature spermatids into mature, motile spermatozoa during a process termed sperm activation. For C. elegans males, sperm activation occurs during insemination of the hermaphrodite and is thought to be mediated by seminal fluid, but the molecular nature of this activity has not been previously identified. Here we show that TRY-5 is a seminal fluid protease that is required in C. elegans for male-mediated sperm activation. We observed that TRY-5::GFP is expressed in the male somatic gonad and is transferred along with sperm to hermaphrodites during mating. In the absence of TRY-5, male seminal fluid loses its potency to transactivate hermaphrodite sperm. However, TRY-5 is not required for either hermaphrodite or male fertility, suggesting that hermaphrodite sperm are normally activated by a distinct hermaphrodite-specific activator to which male sperm are also competent to respond. Within males, TRY-5::GFP localization within the seminal vesicle is antagonized by the protease inhibitor SWM-1. Together, these data suggest that TRY-5 functions as an extracellular activator of C. elegans sperm. The presence of TRY-5 within the seminal fluid couples the timing of sperm activation to that of transfer of sperm into the hermaphrodite uterus, where motility must be rapidly acquired. Our results provide insight into how C. elegans has adopted sex-specific regulation of sperm motility to accommodate its male-hermaphrodite mode of reproduction.

  10. Effects of reduced mitochondrial DNA content on secondary mitochondrial toxicant exposure in Caenorhabditis elegans.

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    Luz, Anthony L; Meyer, Joel N

    2016-09-01

    The mitochondrial genome (mtDNA) is intimately linked to cellular and organismal health, as demonstrated by the fact that mutations in and depletion of mtDNA result in severe mitochondrial disease in humans. However, cells contain hundreds to thousands of copies of mtDNA, which provides genetic redundancy, and creates a threshold effect in which a large percentage of mtDNA must be lost prior to clinical pathogenesis. As certain pharmaceuticals and genetic mutations can result in depletion of mtDNA, and as many environmental toxicants target mitochondria, it is important to understand whether reduced mtDNA will sensitize an individual to toxicant exposure. Here, using ethidium bromide (EtBr), which preferentially inhibits mtDNA replication, we reduced mtDNA 35-55% in the in vivo model organism Caenorhabditis elegans. Chronic, lifelong, low-dose EtBr exposure did not disrupt nematode development or lifespan, and induced only mild alterations in mitochondrial respiration, while having no effect on steady-state ATP levels. Next, we exposed nematodes with reduced mtDNA to the known and suspected mitochondrial toxicants aflatoxin B1, arsenite, paraquat, rotenone or ultraviolet C radiation (UVC). EtBr pre-exposure resulted in mild sensitization of nematodes to UVC and arsenite, had no effect on AfB1 and paraquat, and provided some protection from rotenone toxicity. These mixed results provide a first line of evidence suggesting that reduced mtDNA content may sensitize an individual to certain environmental exposures.

  11. Metalloproteins and phytochelatin synthase may confer protection against zinc oxide nanoparticle induced toxicity in Caenorhabditis elegans.

    Science.gov (United States)

    Polak, Natasa; Read, Daniel S; Jurkschat, Kerstin; Matzke, Marianne; Kelly, Frank J; Spurgeon, David J; Stürzenbaum, Stephen R

    2014-03-01

    Zinc oxide nanoparticles (ZnONPs) are used in large quantities by the cosmetic, food and textile industries. Here we exposed Caenorhabditis elegans wild-type and a metal sensitive triple knockout mutant (mtl-1;mtl-2;pcs-1) to ZnONPs (0-50mg/L) to study strain and exposure specific effects on transcription, reactive oxygen species generation, the biomolecular phenotype (measured by Raman microspectroscopy) and key endpoints of the nematode life cycle (growth, reproduction and lifespan). A significant dissolution effect was observed, where dissolved ZnO constituted over 50% of total Zn within a two day exposure to the test medium, suggesting that the nominal exposure to pure ZnONPs represents in vivo, at best, a mixture exposure of ionic zinc and nanoparticles. Nevertheless, the analyses provided evidence that the metallothioneins (mtl-1 and mtl-2), the phytochelatin synthase (pcs-1) and an apoptotic marker (cep-1) were transcriptionally activated. In addition, the DCFH-DA assay provided in vitro evidence of the oxidative potential of ZnONPs in the metal exposure sensitive triple mutant. Raman spectroscopy highlighted that the biomolecular phenotype changes significantly in the mtl-1;mtl-2;pcs-1 triple knockout worm upon ZnONP exposure, suggesting that these metalloproteins are instrumental in the protection against cytotoxic damage. Finally, ZnONP exposure was shown to decrease growth and development, reproductive capacity and lifespan, effects which were amplified in the triple knockout. By combining diverse toxicological strategies, we identified that individuals (genotypes) housing mutations in key metalloproteins and phytochelatin synthase are more susceptible to ZnONP exposure, which underlines their importance to minimize ZnONP induced toxicity.

  12. A Genome-Wide RNAi Screen for Factors Involved in Neuronal Specification in Caenorhabditis elegans.

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    Richard J Poole

    2011-06-01

    Full Text Available One of the central goals of developmental neurobiology is to describe and understand the multi-tiered molecular events that control the progression of a fertilized egg to a terminally differentiated neuron. In the nematode Caenorhabditis elegans, the progression from egg to terminally differentiated neuron has been visually traced by lineage analysis. For example, the two gustatory neurons ASEL and ASER, a bilaterally symmetric neuron pair that is functionally lateralized, are generated from a fertilized egg through an invariant sequence of 11 cellular cleavages that occur stereotypically along specific cleavage planes. Molecular events that occur along this developmental pathway are only superficially understood. We take here an unbiased, genome-wide approach to identify genes that may act at any stage to ensure the correct differentiation of ASEL. Screening a genome-wide RNAi library that knocks-down 18,179 genes (94% of the genome, we identified 245 genes that affect the development of the ASEL neuron, such that the neuron is either not generated, its fate is converted to that of another cell, or cells from other lineage branches now adopt ASEL fate. We analyze in detail two factors that we identify from this screen: (1 the proneural gene hlh-14, which we find to be bilaterally expressed in the ASEL/R lineages despite their asymmetric lineage origins and which we find is required to generate neurons from several lineage branches including the ASE neurons, and (2 the COMPASS histone methyltransferase complex, which we find to be a critical embryonic inducer of ASEL/R asymmetry, acting upstream of the previously identified miRNA lsy-6. Our study represents the first comprehensive, genome-wide analysis of a single neuronal cell fate decision. The results of this analysis provide a starting point for future studies that will eventually lead to a more complete understanding of how individual neuronal cell types are generated from a single

  13. Fine structure of the Caenorhabditis elegans secretory-excretory system.

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    Nelson, F K; Albert, P S; Riddle, D L

    1983-02-01

    The secretory-excretory system of C. elegans, reconstructed from serial-section electron micrographs of larvae, is composed of four cells, the nuclei of which are located on the ventral side of the pharynx and adjacent intestine. (1) The pore cell encloses the terminal one-third of the excretory duct which leads to an excretory pore at the ventral midline. (2) The duct cell surrounds the excretory duct with a lamellar membrane from the origin of the duct at the excretory sinus to the pore cell boundary. (3) A large H-shaped excretory cell extends bilateral canals anteriorly and posteriorly nearly the entire length of the worm. The excretory sinus within the cell body joins the lumena of the canals with the origin of the duct. (4) A binucleate, A-shaped gland cell extends bilateral processes anteriorly from cell bodies located just behind the pharynx. These processes are fused at the anterior tip of the cell, where the cell enters the circumpharyngeal nerve ring. The processes are also joined at the anterior edge of the excretory cell body, where the excretory cell and gland are joined to the duct cell at the origin of the duct. Secretory granules may be concentrated in the gland near this secretory-excretory junction. Although the gland cells of all growing developmental stages stain positively with paraldehyde-fuchsin, the gland of the dauer larva stage (a developmentally arrested third-stage larva) does not stain, nor do glands of starved worms of other stages. Dauer larvae uniquely lack secretory granules, and the gland cytoplasm is displaced by a labyrinth of large, transparent spaces. Exit from the dauer stage results in the return of active secretory morphology in fourth-stage larvae.

  14. All eggs are not equal: the maternal environment affects progeny reproduction and developmental fate in Caenorhabditis elegans.

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    Simon C Harvey

    Full Text Available BACKGROUND: Maternal effects on progeny traits are common and these can profoundly alter progeny life history. Maternal effects can be adaptive, representing attempts to appropriately match offspring phenotype to the expected environment and are often mediated via trade-offs between progeny number and quality. Here we have investigated the effect of maternal food availability on progeny life history in the free-living nematode Caenorhabditis elegans. METHODOLOGY/PRINCIPAL FINDINGS: The maternal environment affects both reproductive traits and progeny development. Comparisons of the progeny of worms from high and low maternal food environments indicates that low maternal food availability reduces progeny reproduction in good environments, increases progeny reproduction in poor environments and decreases the likelihood that progeny will develop as dauer larvae. These analyses also indicate that the effects on progeny are not a simple consequence of changes in maternal body size, but are associated with an increase in the size of eggs produced by worms at low maternal food availabilities. CONCLUSIONS/SIGNIFICANCE: These results indicate that the maternal environment affects both progeny reproduction and development in C. elegans and therefore that all progeny are not equal. The observed effects are consistent with changes to egg provisioning, which are beneficial in harsh environments, and of changes to progeny development, which are beneficial in harsh environments and detrimental in benign environments. These changes in progeny life history suggest that mothers in poor quality environments may be producing larger eggs that are better suited to poor conditions.

  15. Virulence variations in Shigella and enteroinvasive Escherichia coli using the Caenorhabditis elegans model.

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    Fung, Crystal Ching; Octavia, Sophie; Mooney, Anne-Marie; Lan, Ruiting

    2015-01-01

    Shigella species and enteroinvasive Escherichia coli (EIEC) belong to the same species genetically, with remarkable phenotypic and genomic similarities. Shigella is the main cause of bacillary dysentery with around 160 million annual cases, while EIEC generally induces a milder disease compared to Shigella. This study aimed to determine virulence variations between Shigella and EIEC using the nematode Caenorhabditis elegans as a model host. Caenorhabditis elegans killing- and bacterial colonization assays were performed to examine the potential difference in virulence between Shigella and EIEC strains. Statistically significant difference in the survival rates of nematodes was demonstrated, with Shigella causing death at 88.24 ± 1.20% and EIEC at 94.37 ± 0.70%. The intestinal load of bacteria in the nematodes was found to be 7.65 × 10(4) ± 8.83 × 10(3) and 2.92 × 10(4) ± 6.26 × 10(3) CFU ml(-1) per nematode for Shigella and EIEC, respectively. Shigella dysenteriae serotype 1 which carries the Shiga toxin showed the lowest nematode survival rate at 82.6 ± 3.97% and highest bacterial colonization of 1.75 × 10(5) ± 8.17 × 10(4) CFU ml(-1), whereas a virulence plasmid-negative Shigella strain demonstrated 100 ± 0% nematode survival and lowest bacterial accumulation of 1.02 × 10(4) ± 7.23 × 10(2) CFU ml(-1). This study demonstrates C. elegans as an effective model for examining and comparing Shigella and EIEC virulence variation.

  16. Vulnerability-Based Critical Neurons, Synapses, and Pathways in the Caenorhabditis elegans Connectome

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    Kim, Seongkyun; Kim, Hyoungkyu; Kralik, Jerald D.; Jeong, Jaeseung

    2016-01-01

    Determining the fundamental architectural design of complex nervous systems will lead to significant medical and technological advances. Yet it remains unclear how nervous systems evolved highly efficient networks with near optimal sharing of pathways that yet produce multiple distinct behaviors to reach the organism’s goals. To determine this, the nematode roundworm Caenorhabditis elegans is an attractive model system. Progress has been made in delineating the behavioral circuits of the C. elegans, however, many details are unclear, including the specific functions of every neuron and synapse, as well as the extent the behavioral circuits are separate and parallel versus integrative and serial. Network analysis provides a normative approach to help specify the network design. We investigated the vulnerability of the Caenorhabditis elegans connectome by performing computational experiments that (a) “attacked” 279 individual neurons and 2,990 weighted synaptic connections (composed of 6,393 chemical synapses and 890 electrical junctions) and (b) quantified the effects of each removal on global network properties that influence information processing. The analysis identified 12 critical neurons and 29 critical synapses for establishing fundamental network properties. These critical constituents were found to be control elements—i.e., those with the most influence over multiple underlying pathways. Additionally, the critical synapses formed into circuit-level pathways. These emergent pathways provide evidence for (a) the importance of backward locomotion, avoidance behavior, and social feeding behavior to the organism; (b) the potential roles of specific neurons whose functions have been unclear; and (c) both parallel and serial design elements in the connectome—i.e., specific evidence for a mixed architectural design. PMID:27540747

  17. 秀丽线虫的蛋白质组学研究%Proteomic Research of Caenorhabditis Elegans

    Institute of Scientific and Technical Information of China (English)

    李华玲; 陈文飞; 高玉晓; 王凯; 秦燕; 刘丹丹; 张成岗

    2012-01-01

    The nematode Caenorhabditis elegans_ (C. elegans) has been used in many researches on biological processes. Although mostly known for its research value on modern developmental biology, behavior and neurobiology, genomics, powerful forward and reverse genetics, this model organism has developed into a respectable system for proteomics studies as well and used to complement genetic and RNA interference-based studies of gene function. A number of focused comparative studies contributed to a better understanding of differential gene expression under different temperatures and during development stages, revealed the mechanism of Parkinson, Alzheimer, aging and longevity, insulin signaling related to the human neuro-disease. In addition, C.elegans subproteomes and posttranslational modifications like glycosylation and phosphorylation have been identified and the database are endlessly consummate. Here we describe the history of C.elegans proteomics, especially in neuroscience, and the status of establishment of post-translation modification. Therefore, C.elegans proteomics, in combination of other molecular, biological and genetic techniques, would provide a versatile new tool box for the systematic analysis of gene functions. These studies suggest that C.elegans will be a rich trove for "worm proteomicists".%作为模式生物,秀丽线虫(Caenorhabditis elegans)已经成功地用于许多生命过程的研究,尤其被广泛应用于现代发育生物学、行为与神经生物学、基因组学、正向和反向的遗传学研究中,近年来,秀丽线虫更成为了一个进行蛋白质组学研究的优良体系,诠释了基于基因组学和RNA干涉研究中的基因功能.许多比较蛋白质组学表达谱的建立可以更好地理解线虫在不同发育阶段、不同温度下基因的表达,在与人类神经疾病相关的疾病研究中,线虫对帕金森疾病、阿尔茨海默症、衰老与寿命、胰岛素通路都有所揭示.另外,线虫的亚

  18. cdc-25.4, a Caenorhabditis elegans Ortholog of cdc25, Is Required for Male Mating Behavior

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    Sangmi Oh

    2016-12-01

    Full Text Available Cell division cycle 25 (cdc25 is an evolutionarily conserved phosphatase that promotes cell cycle progression. Among the four cdc25 orthologs in Caenorhabditis elegans, we found that cdc-25.4 mutant males failed to produce outcrossed progeny. This was not caused by defects in sperm development, but by defects in male mating behavior. The cdc-25.4 mutant males showed various defects during male mating, including contact response, backing, turning, and vulva location. Aberrant turning behavior was the most prominent defect in the cdc-25.4 mutant males. We also found that cdc-25.4 is expressed in many neuronal cells throughout development. The turning defect in cdc-25.4 mutant males was recovered by cdc-25.4 transgenic expression in neuronal cells, suggesting that cdc-25.4 functions in neurons for male mating. However, the neuronal morphology of cdc-25.4 mutant males appeared to be normal, as examined with several neuronal markers. Also, RNAi depletion of wee-1.3, a C. elegans ortholog of Wee1/Myt1 kinase, failed to suppress the mating defects of cdc-25.4 mutant males. These findings suggest that, for successful male mating, cdc-25.4 does not target cell cycles that are required for neuronal differentiation and development. Rather, cdc-25.4 likely regulates noncanonical substrates in neuronal cells.

  19. Using Caenorhabditis elegans to Uncover Conserved Functions of Omega-3 and Omega-6 Fatty Acids.

    Science.gov (United States)

    Watts, Jennifer L

    2016-02-02

    The nematode Caenorhabditis elegans is a powerful model organism to study functions of polyunsaturated fatty acids. The ability to alter fatty acid composition with genetic manipulation and dietary supplementation permits the dissection of the roles of omega-3 and omega-6 fatty acids in many biological process including reproduction, aging and neurobiology. Studies in C. elegans to date have mostly identified overlapping functions of 20-carbon omega-6 and omega-3 fatty acids in reproduction and in neurons, however, specific roles for either omega-3 or omega-6 fatty acids are beginning to emerge. Recent findings with importance to human health include the identification of a conserved Cox-independent prostaglandin synthesis pathway, critical functions for cytochrome P450 derivatives of polyunsaturated fatty acids, the requirements for omega-6 and omega-3 fatty acids in sensory neurons, and the importance of fatty acid desaturation for long lifespan. Furthermore, the ability of C. elegans to interconvert omega-6 to omega-3 fatty acids using the FAT-1 omega-3 desaturase has been exploited in mammalian studies and biotechnology approaches to generate mammals capable of exogenous generation of omega-3 fatty acids.

  20. The 3-ureidopropionase of Caenorhabditis elegans, an enzyme involved in pyrimidine degradation.

    Science.gov (United States)

    Janowitz, Tim; Ajonina, Irene; Perbandt, Markus; Woltersdorf, Christian; Hertel, Patrick; Liebau, Eva; Gigengack, Ulrike

    2010-10-01

    Pyrimidines are important metabolites in all cells. Levels of cellular pyrimidines are controlled by multiple mechanisms, with one of these comprising the reductive degradation pathway. In the model invertebrate Caenorhabditis elegans, two of the three enzymes of reductive pyrimidine degradation have previously been characterized. The enzyme catalysing the final step of pyrimidine breakdown, 3-ureidopropionase (β-alanine synthase), had only been identified based on homology. We therefore cloned and functionally expressed the 3-ureidopropionase of C. elegans as hexahistidine fusion protein. The purified recombinant enzyme readily converted the two pyrimidine degradation products: 3-ureidopropionate and 2-methyl-3-ureidopropionate. The enzyme showed a broad pH optimum between pH 7.0 and 8.0. Activity was highest at approximately 40 °C, although the half-life of activity was only 65 s at that temperature. The enzyme showed clear Michaelis-Menten kinetics, with a K(m) of 147 ± 26 μM and a V(max) of 1.1 ± 0.1 U·mg protein(-1). The quaternary structure of the recombinant enzyme was shown to correspond to a dodecamer by 'blue native' gel electrophoresis and gel filtration. The organ specific and subcellular localization of the enzyme was determined using a translational fusion to green fluorescent protein and high expression was observed in striated muscle cells. With the characterization of the 3-ureidopropionase, the reductive pyrimidine degradation pathway in C. elegans has been functionally characterized.

  1. Fatty acids composition of Caenorhabditis elegans using accurate mass GCMS-QTOF.

    Science.gov (United States)

    Henry, Parise; Owopetu, Olufunmilayo; Adisa, Demilade; Nguyen, Thao; Anthony, Kevin; Ijoni-Animadu, David; Jamadar, Sakha; Abdel-Rahman, Fawzia; Saleh, Mahmoud A

    2016-08-02

    The free living nematode Caenorhabditis elegans is a proven model organism for lipid metabolism research. Total lipids of C. elegans were extracted using chloroform and methanol in 2:1 ratio (v/v). Fatty acids composition of the extracted total lipids was converted to their corresponding fatty acids methyl esters (FAMEs) and analyzed by gas chromatography/accurate mass quadrupole time of flight mass spectrometry using both electron ionization and chemical ionization techniques. Twenty-eight fatty acids consisting of 12 to 22 carbon atoms were identified, 65% of them were unsaturated. Fatty acids containing 12 to17 carbons were mostly saturated with stearic acid (18:0) as the major constituent. Several branched-chain fatty acids were identified. Methyl-14-methylhexadecanoate (iso- 17:0) was the major identified branched fatty acid. This is the first report to detect the intact molecular parent ions of the identified fatty acids in C. elegans using chemical ionization compared to electron ionization which produced fragmentations of the FAMEs.

  2. Carqueja (Baccharis trimera Protects against Oxidative Stress and β-Amyloid-Induced Toxicity in Caenorhabditis elegans

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    Franciny Aparecida Paiva

    2015-01-01

    Full Text Available Carqueja (Baccharis trimera is a native plant found throughout South America. Several studies have shown that Carqueja has antioxidant activity in vitro, as well as anti-inflammatory, antidiabetic, analgesic, antihepatotoxic, and antimutagenic properties. However, studies regarding its antioxidant potential in vivo are limited. In this study, we used Caenorhabditis elegans as a model to examine the antioxidant effects of a Carqueja hydroalcoholic extract (CHE on stress resistance and lifespan and to investigate whether CHE has a protective effect in a C. elegans model for Alzheimer's disease. Here, we show for the first time, using in vivo assays, that CHE treatment improved oxidative stress resistance by increasing survival rate and by reducing ROS levels under oxidative stress conditions independently of the stress-related signaling pathways (p38, JNK, and ERK and transcription factors (SKN-1/Nrf and DAF-16/Foxo tested here. CHE treatment also increased the defenses against β-amyloid toxicity in C. elegans, in part by increasing proteasome activity and the expression of two heat shock protein genes. Our findings suggest a potential neuroprotective use for Carqueja, supporting the idea that dietary antioxidants are a promising approach to boost the defensive systems against stress and neurodegeneration.

  3. Mechanism of Different Stereoisomeric Astaxanthin in Resistance to Oxidative Stress in Caenorhabditis elegans.

    Science.gov (United States)

    Liu, Xiaojuan; Luo, Qingxin; Cao, Yong; Goulette, Timothy; Liu, Xin; Xiao, Hang

    2016-09-01

    As a potent antioxidant in human diet, astaxanthin (AST) may play important roles in alleviating oxidative stress-driven adverse physiological effects. This study examined the effects of different stereoisomers of AST in protecting Caenorhabditis elegans from chemically induced oxidative stress. Three stereoisomers of AST investigated herein included 3S,3´S (S) AST, 3R,3´R (R) AST, and a statistical mixture (S: meso: R = 1:2:1) (M) AST. Under paraquat-induced oxidative conditions, all three types of AST significantly enhanced survival rate of C. elegans. The accumulation levels of ROS in the worms were reduced by 40.12%, 30.05%, and 22.04% by S, R, and M AST, respectively (P < 0.05). Compared with R and M AST, S significantly enhanced the expression levels of SOD-3. The results of RNA-Seq analysis demonstrated that AST protected C. elegans from oxidative damage potentially by modulating genes involved in the insulin/insulin-like growth factor (IGF) signaling (IIS) pathway and the oxidoreductase system. It is noteworthy that different stereoisomers of AST showed different effects on the expression levels of various genes related with oxidative stress. This study revealed important information on the in vivo antioxidative effects of AST stereoisomers, which might provide useful information for better utilization of AST.

  4. Identification of vacuoles containing extraintestinal differentiated forms of Legionella pneumophila in colonized Caenorhabditis elegans soil nematodes.

    Science.gov (United States)

    Hellinga, Jacqueline R; Garduño, Rafael A; Kormish, Jay D; Tanner, Jennifer R; Khan, Deirdre; Buchko, Kristyn; Jimenez, Celine; Pinette, Mathieu M; Brassinga, Ann Karen C

    2015-08-01

    Legionella pneumophila, a causative agent of Legionnaires' disease, is a facultative intracellular parasite of freshwater protozoa. Legionella pneumophila features a unique developmental network that involves several developmental forms including the infectious cyst forms. Reservoirs of L. pneumophila include natural and man-made freshwater systems; however, recent studies have shown that isolates of L. pneumophila can also be obtained directly from garden potting soil suggesting the presence of an additional reservoir. A previous study employing the metazoan Caenorhabditis elegans, a member of the Rhabditidae family of free-living soil nematodes, demonstrated that the intestinal lumen can be colonized with L. pneumophila. While both replicative forms and differentiated forms were observed in C. elegans, these morphologically distinct forms were initially observed to be restricted to the intestinal lumen. Using live DIC imaging coupled with focused transmission electron microscopy analyses, we report here that L. pneumophila is able to invade and establish Legionella-containing vacuoles (LCVs) in the intestinal cells. In addition, LCVs containing replicative and differentiated cyst forms were observed in the pseudocoelomic cavity and gonadal tissue of nematodes colonized with L. pneumophila. Furthermore, establishment of LCVs in the gonadal tissue was Dot/Icm dependent and required the presence of the endocytic factor RME-1 to gain access to maturing oocytes. Our findings are novel as this is the first report, to our knowledge, of extraintestinal LCVs containing L. pneumophila cyst forms in C. elegans tissues, highlighting the potential of soil-dwelling nematodes as an alternate environmental reservoir for L. pneumophila.

  5. Caenorhabditis elegans diet significantly affects metabolic profile, mitochondrial DNA levels, lifespan and brood size.

    Science.gov (United States)

    Reinke, S N; Hu, X; Sykes, B D; Lemire, B D

    2010-07-01

    Diet can have profound effects on an organism's health. Metabolic studies offer an effective way to measure and understand the physiological effects of diet or disease. The metabolome is very sensitive to dietary, lifestyle and genetic changes. Caenorhabditis elegans, a soil nematode, is an attractive model organism for metabolic studies because of the ease with which genetic and environmental factors can be controlled. In this work, we report significant effects of diet, mutation and RNA interference on the C.elegans metabolome. Two strains of Escherichia coli, OP50 and HT115 are commonly employed as food sources for maintaining and culturing the nematode. We studied the metabolic and phenotypic effects of culturing wild-type and mutant worms on these two strains of E. coli. We report significant effects of diet on metabolic profile, on mitochondrial DNA copy number and on phenotype. The dietary effects we report are similar in magnitude to the effects of mutations or RNA interference-mediated gene suppression. This is the first critical evaluation of the physiological and metabolic effects on C.elegans of two commonly used culture conditions.

  6. Pathogen-nematode interaction: Nitrogen supply of Listeria monocytogenes during growth in Caenorhabditis elegans.

    Science.gov (United States)

    Kern, Tanja; Kutzner, Erika; Eisenreich, Wolfgang; Fuchs, Thilo M

    2016-02-01

    Listeria monocytogenes is a Gram-positive facultatively intracellular human pathogen. Due to its saprophytic lifestyle, L. monocytogenes is assumed to infect and proliferate within soil organisms such as Caenorhabditis elegans. However, little is known about the nutrient usages and metabolite fluxes in this bacterium-nematode interaction. Here, we established a nematode colonization model for L. monocytogenes and a method for the efficient separation of the pathogen from the nematodal gut. Following (15)N labelling of C. elegans and gas chromatography-mass spectrometry-based (15)N isotopologue analysis, we detected a high basal metabolic rate of the nematode, and observed a significant metabolic flux from nitrogenous compounds of the nematode to listerial proteins during proliferation of the pathogen in the worm's intestine. For comparison, we also measured the N fluxes from the gut content into listerial proteins using completely (15)N-labelled Escherichia coli OP50 as food for C. elegans. In both settings, L. monocytogenes prefers the direct incorporation of histidine, arginine and lysine over their de novo biosynthesis. Our data suggest that colonization of nematodes is a strategy of L. monocytogenes to increase its access to N-rich nutrients.

  7. Establishing Caenorhabditis elegans as a model for Mycobacterium avium subspecies hominissuis infection and intestinal colonization.

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    Everman, Jamie L; Ziaie, Navid R; Bechler, Jessica; Bermudez, Luiz E

    2015-09-24

    The nematode Caenorhabditis elegans has become a model system for studying the disease interaction between pathogens and the host. To determine whether the transparent nematode could serve as a useful model for Mycobacterium avium subspecies hominissuis (MAH) infection of the intestinal tract, worms were fed MAH and assayed for the effects of the bacterial infection on the worm. It was observed during feeding that viable MAH increases in the intestinal lumen in a time dependent manner. Ingestion of MAH was deemed non-toxic to worms as MAH-fed populations have similar survival curves to those fed E. coli strain OP50. Pulse-chase analysis using E. coli strain OP50 revealed that MAH colonize the intestinal tract, as viable MAH remain within the intestine after the assay. Visualization of intestinal MAH using histology and transmission electron microscopy demonstrates that MAH localizes to the intestinal lumen, as well as establishes direct contact with intestinal epithelium. Bacterial colonization appears to have a detrimental effect on the microvilli of the intestinal epithelial cells. The MAH ΔGPL/4B2 strain with a mutation in glycopeptidolipid production is deficient in binding to human epithelial cells (HEp-2), as well as deficient in its ability to bind to and colonize the intestinal tract of C. elegans as efficiently as wild-type MAH. These data indicate the C. elegan