WorldWideScience

Sample records for caenorhabditis elegans studied

  1. Approaches for Studying Autophagy in Caenorhabditis elegans

    Science.gov (United States)

    Chen, Yanfang; Scarcelli, Vincent; Legouis, Renaud

    2017-01-01

    Macroautophagy (hereafter referred to as autophagy) is an intracellular degradative process, well conserved among eukaryotes. By engulfing cytoplasmic constituents into the autophagosome for degradation, this process is involved in the maintenance of cellular homeostasis. Autophagy induction triggers the formation of a cup-shaped double membrane structure, the phagophore, which progressively elongates and encloses materials to be removed. This double membrane vesicle, which is called an autophagosome, fuses with lysosome and forms the autolysosome. The inner membrane of the autophagosome, along with engulfed compounds, are degraded by lysosomal enzymes, which enables the recycling of carbohydrates, amino acids, nucleotides, and lipids. In response to various factors, autophagy can be induced for non-selective degradation of bulk cytoplasm. Autophagy is also able to selectively target cargoes and organelles such as mitochondria or peroxisome, functioning as a quality control system. The modification of autophagy flux is involved in developmental processes such as resistance to stress conditions, aging, cell death, and multiple pathologies. So, the use of animal models is essential for understanding these processes in the context of different cell types throughout the entire lifespan. For almost 15 years, the nematode Caenorhabditis elegans has emerged as a powerful model to analyze autophagy in physiological or pathological contexts. This review presents a rapid overview of physiological processes involving autophagy in Caenorhabditis elegans, the different assays used to monitor autophagy, their drawbacks, and specific tools for the analyses of selective autophagy. PMID:28867808

  2. Approaches for Studying Autophagy in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Yanfang Chen

    2017-08-01

    Full Text Available Macroautophagy (hereafter referred to as autophagy is an intracellular degradative process, well conserved among eukaryotes. By engulfing cytoplasmic constituents into the autophagosome for degradation, this process is involved in the maintenance of cellular homeostasis. Autophagy induction triggers the formation of a cup-shaped double membrane structure, the phagophore, which progressively elongates and encloses materials to be removed. This double membrane vesicle, which is called an autophagosome, fuses with lysosome and forms the autolysosome. The inner membrane of the autophagosome, along with engulfed compounds, are degraded by lysosomal enzymes, which enables the recycling of carbohydrates, amino acids, nucleotides, and lipids. In response to various factors, autophagy can be induced for non-selective degradation of bulk cytoplasm. Autophagy is also able to selectively target cargoes and organelles such as mitochondria or peroxisome, functioning as a quality control system. The modification of autophagy flux is involved in developmental processes such as resistance to stress conditions, aging, cell death, and multiple pathologies. So, the use of animal models is essential for understanding these processes in the context of different cell types throughout the entire lifespan. For almost 15 years, the nematode Caenorhabditis elegans has emerged as a powerful model to analyze autophagy in physiological or pathological contexts. This review presents a rapid overview of physiological processes involving autophagy in Caenorhabditis elegans, the different assays used to monitor autophagy, their drawbacks, and specific tools for the analyses of selective autophagy.

  3. Japanese studies on neural circuits and behavior of Caenorhabditis elegans

    Science.gov (United States)

    Sasakura, Hiroyuki; Tsukada, Yuki; Takagi, Shin; Mori, Ikue

    2013-01-01

    The nematode Caenorhabditis elegans is an ideal organism for studying neural plasticity and animal behaviors. A total of 302 neurons of a C. elegans hermaphrodite have been classified into 118 neuronal groups. This simple neural circuit provides a solid basis for understanding the mechanisms of the brains of higher animals, including humans. Recent studies that employ modern imaging and manipulation techniques enable researchers to study the dynamic properties of nervous systems with great precision. Behavioral and molecular genetic analyses of this tiny animal have contributed greatly to the advancement of neural circuit research. Here, we will review the recent studies on the neural circuits of C. elegans that have been conducted in Japan. Several laboratories have established unique and clever methods to study the underlying neuronal substrates of behavioral regulation in C. elegans. The technological advances applied to studies of C. elegans have allowed new approaches for the studies of complex neural systems. Through reviewing the studies on the neuronal circuits of C. elegans in Japan, we will analyze and discuss the directions of neural circuit studies. PMID:24348340

  4. 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.

  5. Survival assays using Caenorhabditis elegans.

    Science.gov (United States)

    Park, Hae-Eun H; Jung, Yoonji; Lee, Seung-Jae V

    2017-02-01

    Caenorhabditis elegans is an important model organism with many useful features, including rapid development and aging, easy cultivation, and genetic tractability. Survival assays using C. elegans are powerful methods for studying physiological processes. In this review, we describe diverse types of C. elegans survival assays and discuss the aims, uses, and advantages of specific assays. C. elegans survival assays have played key roles in identifying novel genetic factors that regulate many aspects of animal physiology, such as aging and lifespan, stress response, and immunity against pathogens. Because many genetic factors discovered using C. elegans are evolutionarily conserved, survival assays can provide insights into mechanisms underlying physiological processes in mammals, including humans.

  6. Proteomic analysis of Caenorhabditis elegans

    Science.gov (United States)

    Proteomic studies of the free-living nematode Caenorhabditis elegans have recently received great attention because this animal is a useful model platform for the in vivo study of various biological problems relevant to human disease. In general, proteomic analysis is performed in order to address a...

  7. 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

  8. 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.

  9. Caenorhabditis elegans as a model to study renal development and disease: sexy cilia.

    Science.gov (United States)

    Barr, Maureen M

    2005-02-01

    The nematode Caenorhabditis elegans has no kidney per se, yet "the worm" has proved to be an excellent model to study renal-related issues, including tubulogenesis of the excretory canal, membrane transport and ion channel function, and human genetic diseases including autosomal dominant polycystic kidney disease (ADPKD). The goal of this review is to explain how C. elegans has provided insight into cilia development, cilia function, and human cystic kidney diseases.

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

    Science.gov (United States)

    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…

  11. The glia of Caenorhabditis elegans.

    Science.gov (United States)

    Oikonomou, Grigorios; Shaham, Shai

    2011-09-01

    Glia have been, in many ways, the proverbial elephant in the room. Although glia are as numerous as neurons in vertebrate nervous systems, technical and other concerns had left research on these cells languishing, whereas research on neurons marched on. Importantly, model systems to study glia had lagged considerably behind. A concerted effort in recent years to develop the canonical invertebrate model animals, Drosophila melanogaster and Caenorhabditis elegans, as settings to understand glial roles in nervous system development and function has begun to bear fruit. In this review, we summarize our current understanding of glia and their roles in the nervous system of the nematode C. elegans. The recent studies we describe highlight the similarities and differences between C. elegans and vertebrate glia, and focus on novel insights that are likely to have general relevance to all nervous systems. Copyright © 2010 Wiley-Liss, Inc.

  12. Comparative genomics and functional study of lipid metabolic genes in Caenorhabditis elegans

    Science.gov (United States)

    2013-01-01

    Background Animal models are indispensable to understand the lipid metabolism and lipid metabolic diseases. Over the last decade, the nematode Caenorhabditis elegans has become a popular animal model for exploring the regulation of lipid metabolism, obesity, and obese-related diseases. However, the genomic and functional conservation of lipid metabolism from C. elegans to humans remains unknown. In the present study, we systematically analyzed genes involved in lipid metabolism in the C. elegans genome using comparative genomics. Results We built a database containing 471 lipid genes from the C. elegans genome, and then assigned most of lipid genes into 16 different lipid metabolic pathways that were integrated into a network. Over 70% of C. elegans lipid genes have human orthologs, with 237 of 471 C. elegans lipid genes being conserved in humans, mice, rats, and Drosophila, of which 71 genes are specifically related to human metabolic diseases. Moreover, RNA-mediated interference (RNAi) was used to disrupt the expression of 356 of 471 lipid genes with available RNAi clones. We found that 21 genes strongly affect fat storage, development, reproduction, and other visible phenotypes, 6 of which have not previously been implicated in the regulation of fat metabolism and other phenotypes. Conclusions This study provides the first systematic genomic insight into lipid metabolism in C. elegans, supporting the use of C. elegans as an increasingly prominent model in the study of metabolic diseases. PMID:23496871

  13. Imaging metals in Caenorhabditis elegans.

    Science.gov (United States)

    Aschner, M; Palinski, C; Sperling, M; Karst, U; Schwerdtle, T; Bornhorst, J

    2017-04-19

    Systemic trafficking and storage of essential metal ions play fundamental roles in living organisms by serving as essential cofactors in various cellular processes. Thereby metal quantification and localization are critical steps in understanding metal homeostasis, and how their dyshomeostasis might contribute to disease etiology and the ensuing pathologies. Furthermore, the amount and distribution of metals in organisms can provide insight into their underlying mechanisms of toxicity and toxicokinetics. While in vivo studies on metal imaging in mammalian experimental animals are complex, time- and resource-consuming, the nematode Caenorhabditis elegans (C. elegans) provides a suitable comparative and complementary model system. Expressing homologous genes to those inherent to mammals, including those that regulate metal homeostasis and transport, C. elegans has become a powerful tool to study metal homeostasis and toxicity. A number of recent technical advances have been made in the development and application of analytical methods to visualize metal ions in C. elegans. Here, we briefly summarize key findings and challenges of the three main techniques and their application to the nematode, namely sensing fluorophores, microbeam synchrotron radiation X-ray fluorescence as well as laser ablation (LA) coupled to inductively coupled plasma-mass spectrometry (ICP-MS).

  14. Molecular mechanisms of Caenorhabditis elegans - Bacillus interactions

    OpenAIRE

    Iatsenko, Igor

    2014-01-01

    Pathogens represent strong evolutionary forces driving the complexity of the host defense system. The nematode Caenorhabditis elegans has been widely used as a genetically amenable invertebrate for studying host-pathogen interactions. While the C. elegans model provided invaluable insights into innate defense pathways against infections, it remains to be discovered what the role of these pathways is in other nematodes and how they shape the evolution of bacterial pathogenicity. The nematode P...

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

    Science.gov (United States)

    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

  16. Riboflavin transporter-2 (rft-2) of Caenorhabditis elegans: Adaptive ...

    Indian Academy of Sciences (India)

    -3 (hR VFT-3), are identified and characterized in Caenorhabditis elegans. However, studies pertaining to functional contribution of rft-2 in maintaining body homeostatic riboflavin levels and its regulation are very limited. In this study, the ...

  17. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    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

  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. Mainstreaming Caenorhabditis elegans in experimental evolution.

    Science.gov (United States)

    Gray, Jeremy C; Cutter, Asher D

    2014-03-07

    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.

  20. Mainstreaming Caenorhabditis elegans in experimental evolution

    Science.gov (United States)

    Gray, Jeremy C.; Cutter, Asher D.

    2014-01-01

    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. PMID:24430852

  1. Comparative active-site mutation study of human and Caenorhabditis elegans thymidine kinase 1

    DEFF Research Database (Denmark)

    Skovgaard, Tine; Uhlin, Ulla; Munch-Petersen, Birgitte

    2012-01-01

    The first step for the intracellular retention of several anticancer or antiviral nucleoside analogues is the addition of a phosphate group catalysed by a deoxyribonucleoside kinase such as thymidine kinase 1 (TK1). Recently, human TK1 (HuTK1) has been crystallized and characterized using different...... ligands. To improve our understanding of TK1 substrate specificity, we performed a detailed, mutation-based comparative structure-function study of the active sites of two thymidine kinases: HuTK1 and Caenorhabditis elegans TK1 (CeTK1). Specifically, mutations were introduced into the hydrophobic pocket...... surrounding the substrate base. In CeTK1, some of these mutations led to increased activity with deoxycytidine and deoxyguanosine, two unusual substrates for TK1-like kinases. In HuTK1, mutation of T163 to S resulted in a kinase with a 140-fold lower K(m) for the antiviral nucleoside analogue 3'-azido-3...

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

    Directory of Open Access Journals (Sweden)

    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.

  3. The development of sexual dimorphism: studies of the Caenorhabditis elegans male.

    Science.gov (United States)

    Emmons, Scott W

    2014-01-01

    Studies of the development of the Caenorhabditis elegans male have been carried out with the aim of understanding the basis of sexual dimorphism. Postembryonic development of the two C. elegans sexes differs extensively. Development along either the hermaphrodite or male pathway is specified initially by the X to autosome ratio. The regulatory events initiated by this ratio include a male-determining paracrine intercellular signal. Expression of this signal leads to different consequences in three regions of the body: the nongonadal soma, the somatic parts of the gonad, and the germ line. In the nongonadal soma, activity of the key Zn-finger transcription factor TRA-1 determines hermaphrodite development; in its absence, the male pathway is followed. Only a few genes directly regulated by TRA-1 are currently known, including members of the evolutionarily conserved, male-determining DM domain Zn-finger transcription factors. In the somatic parts of the gonad and germ line, absence of TRA-1 activity is not sufficient for full expression of the male pathway. Several additional transcription factors involved have been identified. In the germ line, regulatory genes for sperm development that act at the level of RNA in the cytoplasm play a prominent role. © 2014 Wiley Periodicals, Inc.

  4. 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.

  5. Cell Biology of the Caenorhabditis elegans Nucleus.

    Science.gov (United States)

    Cohen-Fix, Orna; Askjaer, Peter

    2017-01-01

    Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology. Copyright © 2017 by the Genetics Society of America.

  6. 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)

  7. Use of Caenorhabditis elegans as a model to study Alzheimer’s disease and other neurodegenerative diseases

    Science.gov (United States)

    Alexander, Adanna G.; Marfil, Vanessa; Li, Chris

    2014-01-01

    Advances in research and technology has increased our quality of life, allowed us to combat diseases, and achieve increased longevity. Unfortunately, increased longevity is accompanied by a rise in the incidences of age-related diseases such as Alzheimer’s disease (AD). AD is the sixth leading cause of death, and one of the leading causes of dementia amongst the aged population in the USA. It is a progressive neurodegenerative disorder, characterized by the prevalence of extracellular Aβ plaques and intracellular neurofibrillary tangles, derived from the proteolysis of the amyloid precursor protein (APP) and the hyperphosphorylation of microtubule-associated protein tau, respectively. Despite years of extensive research, the molecular mechanisms that underlie the pathology of AD remain unclear. Model organisms, such as the nematode, Caenorhabditis elegans, present a complementary approach to addressing these questions. C. elegans has many advantages as a model system to study AD and other neurodegenerative diseases. Like their mammalian counterparts, they have complex biochemical pathways, most of which are conserved. Genes in which mutations are correlated with AD have counterparts in C. elegans, including an APP-related gene, apl-1, a tau homolog, ptl-1, and presenilin homologs, such as sel-12 and hop-1. Since the neuronal connectivity in C. elegans has already been established, C. elegans is also advantageous in modeling learning and memory impairments seen during AD. This article addresses the insights C. elegans provide in studying AD and other neurodegenerative diseases. Additionally, we explore the advantages and drawbacks associated with using this model. PMID:25250042

  8. Caenorhabditis elegans as a platform to study the mechanism of action of synthetic antitumor lipids

    Science.gov (United States)

    Sánchez-Blanco, Adolfo; Rodríguez-Matellán, Alberto G; Reis-Sobreiro, Mariana; Sáenz-Narciso, Beatriz; Cabello, Juan; Mohler, William A; Mollinedo, Faustino

    2014-01-01

    Drugs capable of specifically recognizing and killing cancer cells while sparing healthy cells are of great interest in anti-cancer therapy. An example of such a drug is edelfosine, the prototype molecule of a family of synthetic lipids collectively known as antitumor lipids (ATLs). A better understanding of the selectivity and the mechanism of action of these compounds would lead to better anticancer treatments. Using Caenorhabditis elegans, we modeled key features of the ATL selectivity against cancer cells. Edelfosine induced a selective and direct killing action on C. elegans embryos, which was dependent on cholesterol, without affecting adult worms and larvae. Distinct ATLs ranked differently in their embryonic lethal effect with edelfosine > perifosine > erucylphosphocholine >> miltefosine. Following a biased screening of 57 C. elegans mutants we found that inactivation of components of the insulin/IGF-1 signaling pathway led to resistance against the ATL edelfosine in both C. elegans and human tumor cells. This paper shows that C. elegans can be used as a rapid platform to facilitate ATL research and to further understand the mechanism of action of edelfosine and other synthetic ATLs. PMID:25485582

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

    Science.gov (United States)

    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 the organism level, our automated system analyzes hundreds of individual animals for body length, locomotion speed, and lifespan. To demonstrate the utility of our system, we applied this technology to test the toxicity of 20 nanomaterials under four concentrations. Only fullerene nanoparticles (nC60), fullerol, TiO2, and CeO2 showed little or no toxicity. Various degrees of toxicity were detected from different forms of carbon nanotubes, graphene, carbon black, Ag, and fumed SiO2 nanoparticles. Aminofullerene and UV irradiated nC60 also showed small but significant toxicity. We further investigated the effects of nanomaterial size, shape, surface chemistry, and exposure conditions on toxicity. Our data are publicly available at the open-access nanotoxicity database www.QuantWorm.org/nano. PMID:25611253

  10. Combining Human Epigenetics and Sleep Studies in Caenorhabditis elegans: A Cross-Species Approach for Finding Conserved Genes Regulating Sleep.

    Science.gov (United States)

    Huang, Huiyan; Zhu, Yong; Eliot, Melissa N; Knopik, Valerie S; McGeary, John E; Carskadon, Mary A; Hart, Anne C

    2017-06-01

    We aimed to test a combined approach to identify conserved genes regulating sleep and to explore the association between DNA methylation and sleep length. We identified candidate genes associated with shorter versus longer sleep duration in college students based on DNA methylation using Illumina Infinium HumanMethylation450 BeadChip arrays. Orthologous genes in Caenorhabditis elegans were identified, and we examined whether their loss of function affected C. elegans sleep. For genes whose perturbation affected C. elegans sleep, we subsequently undertook a small pilot study to re-examine DNA methylation in an independent set of human participants with shorter versus longer sleep durations. Eighty-seven out of 485,577 CpG sites had significant differential methylation in young adults with shorter versus longer sleep duration, corresponding to 52 candidate genes. We identified 34 C. elegans orthologs, including NPY/flp-18 and flp-21, which are known to affect sleep. Loss of five additional genes alters developmentally timed C. elegans sleep (B4GALT6/bre-4, DOCK180/ced-5, GNB2L1/rack-1, PTPRN2/ida-1, ZFYVE28/lst-2). For one of these genes, ZFYVE28 (also known as hLst2), the pilot replication study again found decreased DNA methylation associated with shorter sleep duration at the same two CpG sites in the first intron of ZFYVE28. Using an approach that combines human epigenetics and C. elegans sleep studies, we identified five genes that play previously unidentified roles in C. elegans sleep. We suggest sleep duration in humans may be associated with differential DNA methylation at specific sites and that the conserved genes identified here likely play roles in C. elegans sleep and in other species.

  11. 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

  12. Programmed Cell Death During Caenorhabditis elegans Development

    Science.gov (United States)

    Conradt, Barbara; Wu, Yi-Chun; Xue, Ding

    2016-01-01

    Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of dying cells. Molecular, cell biological, and biochemical studies have revealed the underlying mechanisms that control these three phases of programmed cell death. In particular, the interplay of transcriptional regulatory cascades and networks involving multiple transcriptional regulators is crucial in activating the expression of the key death-inducing gene egl-1 and, in some cases, the ced-3 gene in cells destined to die. A protein interaction cascade involving EGL-1, CED-9, CED-4, and CED-3 results in the activation of the key cell death protease CED-3, which is tightly controlled by multiple positive and negative regulators. The activation of the CED-3 caspase then initiates the cell disassembly process by cleaving and activating or inactivating crucial CED-3 substrates; leading to activation of multiple cell death execution events, including nuclear DNA fragmentation, mitochondrial elimination, phosphatidylserine externalization, inactivation of survival signals, and clearance of apoptotic cells. Further studies of programmed cell death in C. elegans will continue to advance our understanding of how programmed cell death is regulated, activated, and executed in general. PMID:27516615

  13. Programmed Cell Death During Caenorhabditis elegans Development.

    Science.gov (United States)

    Conradt, Barbara; Wu, Yi-Chun; Xue, Ding

    2016-08-01

    Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of dying cells. Molecular, cell biological, and biochemical studies have revealed the underlying mechanisms that control these three phases of programmed cell death. In particular, the interplay of transcriptional regulatory cascades and networks involving multiple transcriptional regulators is crucial in activating the expression of the key death-inducing gene egl-1 and, in some cases, the ced-3 gene in cells destined to die. A protein interaction cascade involving EGL-1, CED-9, CED-4, and CED-3 results in the activation of the key cell death protease CED-3, which is tightly controlled by multiple positive and negative regulators. The activation of the CED-3 caspase then initiates the cell disassembly process by cleaving and activating or inactivating crucial CED-3 substrates; leading to activation of multiple cell death execution events, including nuclear DNA fragmentation, mitochondrial elimination, phosphatidylserine externalization, inactivation of survival signals, and clearance of apoptotic cells. Further studies of programmed cell death in C. elegans will continue to advance our understanding of how programmed cell death is regulated, activated, and executed in general. Copyright © 2016 by the Genetics Society of America.

  14. Dietary choice behavior in Caenorhabditis elegans

    OpenAIRE

    Shtonda, Boris Borisovich; Avery, Leon

    2006-01-01

    Animals have evolved diverse behaviors that serve the purpose of finding food in the environment. We investigated the food seeking strategy of the soil bacteria-eating nematode Caenorhabditis elegans. C. elegans bacterial food varies in quality: some species are easy to eat and support worm growth well, while others do not. We show that worms exhibit dietary choice: they hunt for high quality food and leave hard-to-eat bacteria. This food seeking behavior is enhanced in animals that have alre...

  15. 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.

  16. Molecular control of memory in nematode Caenorhabditis elegans

    OpenAIRE

    Ye, Hua-Yue; Ye, Bo-Ping; Wang, Da-Yong

    2008-01-01

    Model invertebrate organism Caenorhabditis elegans has become an ideal model to unravel the complex processes of memory. C. elegans has three simple forms of memory: memory for thermosensation, memory for chemosensation, and memory for mechanosensation. In the form of memory for mechanosensation, short-term memory, intermediate-term memory, and long-term memory have been extensively studied. The short-term memory and intermediate-term memory may occur in the presynaptic sensory neurons, where...

  17. The Natural Biotic Environment of Caenorhabditis elegans.

    Science.gov (United States)

    Schulenburg, Hinrich; Félix, Marie-Anne

    2017-05-01

    Organisms evolve in response to their natural environment. Consideration of natural ecological parameters are thus of key importance for our understanding of an organism's biology. Curiously, the natural ecology of the model species Caenorhabditis elegans has long been neglected, even though this nematode has become one of the most intensively studied models in biological research. This lack of interest changed ∼10 yr ago. Since then, an increasing number of studies have focused on the nematode's natural ecology. Yet many unknowns still remain. Here, we provide an overview of the currently available information on the natural environment of C. elegans We focus on the biotic environment, which is usually less predictable and thus can create high selective constraints that are likely to have had a strong impact on C. elegans evolution. This nematode is particularly abundant in microbe-rich environments, especially rotting plant matter such as decomposing fruits and stems. In this environment, it is part of a complex interaction network, which is particularly shaped by a species-rich microbial community. These microbes can be food, part of a beneficial gut microbiome, parasites and pathogens, and possibly competitors. C. elegans is additionally confronted with predators; it interacts with vector organisms that facilitate dispersal to new habitats, and also with competitors for similar food environments, including competitors from congeneric and also the same species. Full appreciation of this nematode's biology warrants further exploration of its natural environment and subsequent integration of this information into the well-established laboratory-based research approaches. Copyright © 2017 by the Genetics Society of America.

  18. The Natural Biotic Environment of Caenorhabditis elegans

    Science.gov (United States)

    Schulenburg, Hinrich; Félix, Marie-Anne

    2017-01-01

    Organisms evolve in response to their natural environment. Consideration of natural ecological parameters are thus of key importance for our understanding of an organism’s biology. Curiously, the natural ecology of the model species Caenorhabditis elegans has long been neglected, even though this nematode has become one of the most intensively studied models in biological research. This lack of interest changed ∼10 yr ago. Since then, an increasing number of studies have focused on the nematode’s natural ecology. Yet many unknowns still remain. Here, we provide an overview of the currently available information on the natural environment of C. elegans. We focus on the biotic environment, which is usually less predictable and thus can create high selective constraints that are likely to have had a strong impact on C. elegans evolution. This nematode is particularly abundant in microbe-rich environments, especially rotting plant matter such as decomposing fruits and stems. In this environment, it is part of a complex interaction network, which is particularly shaped by a species-rich microbial community. These microbes can be food, part of a beneficial gut microbiome, parasites and pathogens, and possibly competitors. C. elegans is additionally confronted with predators; it interacts with vector organisms that facilitate dispersal to new habitats, and also with competitors for similar food environments, including competitors from congeneric and also the same species. Full appreciation of this nematode’s biology warrants further exploration of its natural environment and subsequent integration of this information into the well-established laboratory-based research approaches. PMID:28476862

  19. Caenorhabditis elegans as a model system for studying non-cell-autonomous mechanisms in protein-misfolding diseases

    Directory of Open Access Journals (Sweden)

    Carmen I. Nussbaum-Krammer

    2014-01-01

    Full Text Available Caenorhabditis elegans has a number of distinct advantages that are useful for understanding the basis for cellular and organismal dysfunction underlying age-associated diseases of protein misfolding. Although protein aggregation, a key feature of human neurodegenerative diseases, has been typically explored in vivo at the single-cell level using cells in culture, there is now increasing evidence that proteotoxicity has a non-cell-autonomous component and is communicated between cells and tissues in a multicellular organism. These discoveries have opened up new avenues for the use of C. elegans as an ideal animal model system to study non-cell-autonomous proteotoxicity, prion-like propagation of aggregation-prone proteins, and the organismal regulation of stress responses and proteostasis. This Review focuses on recent evidence that C. elegans has mechanisms to transmit certain classes of toxic proteins between tissues and a complex stress response that integrates and coordinates signals from single cells and tissues across the organism. These findings emphasize the potential of C. elegans to provide insights into non-cell-autonomous proteotoxic mechanisms underlying age-related protein-misfolding diseases.

  20. Models of Caenorhabditis elegans infection by bacterial and fungal pathogens.

    Science.gov (United States)

    Powell, Jennifer R; Ausubel, Frederick M

    2008-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the relationship between the animal innate immune system and a variety of bacterial and fungal pathogens. Extensive genetic and molecular tools are available in C. elegans, facilitating an in-depth analysis of host defense factors and pathogen virulence factors. Many of these factors are conserved in insects and mammals, indicating the relevance of the nematode model to the vertebrate innate immune response. Here, we describe pathogen assays for a selection of the most commonly studied bacterial and fungal pathogens using the C. elegans model system.

  1. Radiobiological studies with the nematode Caenorhabditis elegans. Genetic and developmental effects of high LET radiation

    Science.gov (United States)

    Nelson, G. A.; Schubert, W. W.; Marshall, T. M.

    1992-01-01

    The biological effects of heavy charged particle (HZE) radiation are of particular interest to travellers and planners for long-duration space flights where exposure levels represent a potential health hazard. The unique feature of HZE radiation is the structured pattern of its energy deposition in targets. There are many consequences of this feature to biological endpoints when compared with effects of ionizing photons. Dose vs response and dose-rate kinetics may be modified, DNA and cellular repair systems may be altered in their abilities to cope with damage, and the qualitative features of damage may be unique for different ions. The nematode Caenorhabditis elegans is being used to address these and related questions associated with exposure to radiation. HZE-induced mutation, chromosome aberration, cell inactivation and altered organogenesis are discussed along with plans for radiobiological experiments in space.

  2. Antagonistic sensory cues generate gustatory plasticity in Caenorhabditis elegans

    NARCIS (Netherlands)

    R.K. Hukema (Renate); S. Rademakers (Suzanne); M.P.J. Dekkers (Martijn); J.A. Burghoorn (Jan); G. Jansen (Gert)

    2006-01-01

    textabstractCaenorhabditis elegans shows chemoattraction to 0.1-200 mM NaCl, avoidance of higher NaCl concentrations, and avoidance of otherwise attractive NaCl concentrations after prolonged exposure to NaCl (gustatory plasticity). Previous studies have shown that the ASE and ASH sensory neurons

  3. The many glia of a tiny nematode: studying glial diversity using Caenorhabditis elegans.

    Science.gov (United States)

    Mizeracka, Karolina; Heiman, Maxwell G

    2015-01-01

    Glia constitute a major, understudied population of cells in the nervous system. Currently, it is appreciated that these cells exhibit vast morphological, functional, and molecular diversity, but our understanding of glial biology is limited. Some key unanswered questions include how glial diversity is generated during development and what functions distinct glial subtypes serve in the mature nervous system. The nematode Caenorhabditis elegans contains a defined set of glia, which have clear morphological and molecular differences, and thus provides a simplified model for understanding glial diversity. In addition, recent experiments suggest that the molecular mechanisms underlying the generation of glial diversity in C. elegans are conserved with those in mammals. In this review, we summarize the surprising diversity of glial subtypes present in this simple organism, and highlight current thinking about what roles they perform in the nervous system. We emphasize how genetic approaches may be used to identify the mechanistic origins of glial diversity, which is key to understanding how glia function in health and disease. For further resources related to this article, please visit the WIREs website. The authors have declared no conflicts of interest for this article. © 2015 Wiley Periodicals, Inc.

  4. Monitoring Autophagic Responses in Caenorhabditis elegans.

    Science.gov (United States)

    Papandreou, M E; Tavernarakis, N

    2017-01-01

    Autophagy, from the Greek auto (self) and phagy (eating), is a self-degradative process critical for eukaryotic cell homeostasis. Its rapidly responsive, highly dynamic nature renders this process essential for adapting to and offsetting acute/harsh conditions such as starvation, organelle dysfunction, and deoxyribonucleic acid (DNA) damage. Autophagy involves an intricate network of interacting factors with multiple levels of control. Importantly, dysregulation of autophagy has been linked to numerous debilitating pathologies, including cancer and neurodegenerative conditions in humans. Methods to monitor and quantify autophagic activity reliably are essential both for studying the basic mechanisms of autophagy and for dissecting its involvement in disease. The nematode Caenorhabditis elegans is a particularly suitable model organism to effectively visualize and study autophagy, in vivo, in a physiological and pathological context due to its optical transparency, experimental malleability, and precise developmental and anatomical characterization. Here, we outline the main tools and approaches to monitor and measure autophagic responses in C. elegans. © 2017 Elsevier Inc. All rights reserved.

  5. 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

  6. Using a health-rating system to evaluate the usefulness of Caenorhabditis elegans as a model for anthelmintic study.

    Directory of Open Access Journals (Sweden)

    Kathryn J Weaver

    Full Text Available Soil-transmitted helminths (STHs are intestinal parasitic nematodes that infect humans, and are transmitted through contaminated soil. These nematodes include the large roundworm (Ascaris lumbricoides, whipworm (Trichuris trichiura, and hookworm (Ancylostoma ceylanicum, Ancylostoma duodenale, and Necator americanus. Nearly 1.5 billion people (~24% of the population worldwide are infected with at least one species of these parasites, burdening the poor, in particular, children and pregnant women. To combat these diseases, the WHO only recognizes four anthelmintic drugs, including the preferred drug, albendazole, for mass drug administration (MDA. These four drugs have a total of two different mechanisms of action, and, as expected, resistance has been observed. This problem calls for new drugs with different mechanisms of action. Although there is precedence for the use of Caenorhabditis elegans (C. elegans, a free-living nematode, as a model for drug screening and anthelmintic testing, their usefulness for such anthelmintic study is not clear as past research has shown that C. elegans did not show a strong response to albendazole, the MDA drug of choice, in comparison with various STHs under similar treatment. To further examine if C. elegans has the potential to be a good model organism for anthelmintic drug study, we employed a health rating scale in order to tease out potential effects of albendazole, and other anthelmintics, that may have been missed using a binary, dead/alive scale. Using the health-rating scale we found that although the worms may have not been dying, they were sick, showing dose responses to anthelmintic drugs, including albendazole, reinforcing C. elegans as a useful model for anthelmintic study.

  7. Precision Electrophile Tagging in Caenorhabditis elegans.

    Science.gov (United States)

    Long, Marcus J C; Urul, Daniel A; Chawla, Shivansh; Lin, Hong-Yu; Zhao, Yi; Haegele, Joseph A; Wang, Yiran; Aye, Yimon

    2018-01-16

    Adduction of an electrophile to privileged sensor proteins and the resulting phenotypically dominant responses are increasingly appreciated as being essential for metazoan health. Functional similarities between the biological electrophiles and electrophilic pharmacophores commonly found in covalent drugs further fortify the translational relevance of these small-molecule signals. Genetically encodable or small-molecule-based fluorescent reporters and redox proteomics have revolutionized the observation and profiling of cellular redox states and electrophile-sensor proteins, respectively. However, precision mapping between specific redox-modified targets and specific responses has only recently begun to be addressed, and systems tractable to both genetic manipulation and on-target redox signaling in vivo remain largely limited. Here we engineer transgenic Caenorhabditis elegans expressing functional HaloTagged fusion proteins and use this system to develop a generalizable light-controlled approach to tagging a prototypical electrophile-sensor protein with native electrophiles in vivo. The method circumvents issues associated with low uptake/distribution and toxicity/promiscuity. Given the validated success of C. elegans in aging studies, this optimized platform offers a new lens with which to scrutinize how on-target electrophile signaling influences redox-dependent life span regulation.

  8. Structural properties of the Caenorhabditis elegans neuronal network

    National Research Council Canada - National Science Library

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

    2011-01-01

    .... 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...

  9. Genetic kidney diseases: Caenorhabditis elegans as model system.

    Science.gov (United States)

    Ganner, Athina; Neumann-Haefelin, Elke

    2017-07-01

    Despite its apparent simplicity, the nematode Caenorhabditis elegans has a high rating as a model in molecular and developmental biology and biomedical research. C. elegans has no excretory system comparable with the mammalian kidney but many of the genes and molecular pathways involved in human kidney diseases are conserved in C. elegans. The plethora of genetic, molecular and imaging tools available in C. elegans has enabled major discoveries in renal research and advanced our understanding of the pathogenesis of genetic kidney diseases. In particular, studies in C. elegans have pioneered the fundamental role of cilia for cystic kidney diseases. In addition, proteins of the glomerular filtration barrier and podocytes are critical for cell recognition, assembly of functional neuronal circuits, mechanosensation and signal transduction in C. elegans. C. elegans has also proved tremendously valuable for aging research and the Von Hippel-Lindau tumor suppressor gene has been shown to modulate lifespan in the nematode. Further, studies of the excretory canal, membrane transport and ion channel function in C. elegans have provided insights into mechanisms of tubulogenesis and cellular homeostasis. This review recounts the way that C. elegans can be used to investigate various aspects of genetic and molecular nephrology. This model system opens up an exciting and new area of study of renal development and diseases.

  10. A comparative study of fat storage quantitation in nematode Caenorhabditis elegans using label and label-free methods.

    Directory of Open Access Journals (Sweden)

    Kelvin Yen

    Full Text Available The nematode Caenorhabditis elegans has been employed as a model organism to study human obesity due to the conservation of the pathways that regulate energy metabolism. To assay for fat storage in C. elegans, a number of fat-soluble dyes have been employed including BODIPY, Nile Red, Oil Red O, and Sudan Black. However, dye-labeled assays produce results that often do not correlate with fat stores in C. elegans. An alternative label-free approach to analyze fat storage in C. elegans has recently been described with coherent anti-Stokes Raman scattering (CARS microscopy. Here, we compare the performance of CARS microscopy with standard dye-labeled techniques and biochemical quantification to analyze fat storage in wild type C. elegans and with genetic mutations in the insulin/IGF-1 signaling pathway including the genes daf-2 (insulin/IGF-1 receptor, rict-1 (rictor and sgk-1 (serum glucocorticoid kinase. CARS imaging provides a direct measure of fat storage with unprecedented details including total fat stores as well as the size, number, and lipid-chain unsaturation of individual lipid droplets. In addition, CARS/TPEF imaging reveals a neutral lipid species that resides in both the hypodermis and the intestinal cells and an autofluorescent organelle that resides exclusively in the intestinal cells. Importantly, coherent addition of the CARS fields from the C-H abundant neutral lipid permits selective CARS imaging of the fat store, and further coupling of spontaneous Raman analysis provides unprecedented details including lipid-chain unsaturation of individual lipid droplets. We observe that although daf-2, rict-1, and sgk-1 mutants affect insulin/IGF-1 signaling, they exhibit vastly different phenotypes in terms of neutral lipid and autofluorescent species. We find that CARS imaging gives quantification similar to standard biochemical triglyceride quantification. Further, we independently confirm that feeding worms with vital dyes does not lead

  11. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Troemel, Emily R; Félix, Marie-Anne; Whiteman, Noah K; Barrière, Antoine; Ausubel, Frederick M

    2008-12-09

    For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF) signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes.

  12. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Emily R Troemel

    2008-12-01

    Full Text Available For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes.

  13. 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.

  14. Immobilization of Caenorhabditis elegans to Analyze Intracellular Transport in Neurons.

    Science.gov (United States)

    Niwa, Shinsuke

    2017-10-18

    Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein are molecular motors that regulate anterograde and retrograde transport, respectively. These motors use microtubule networks as rails. Caenorhabditis elegans (C. elegans) is a powerful model organism to study axonal transport and IFT in vivo. Here, I describe a protocol to observe axonal transport and IFT in living C. elegans. Transported cargo can be visualized by tagging cargo proteins using fluorescent proteins such as green fluorescent protein (GFP). C. elegans is transparent and GFP-tagged cargo proteins can be expressed in specific cells under cell-specific promoters. Living worms can be fixed by microbeads on 10% agarose gel without killing or anesthetizing the worms. Under these conditions, cargo movement can be directly observed in the axons and cilia of living C. elegans without dissection. This method can be applied to the observation of any cargo molecule in any cells by modifying the target proteins and/or the cells they are expressed in. Most basic proteins such as molecular motors and adaptor proteins that are involved in axonal transport and IFT are conserved in C. elegans. Compared to other model organisms, mutants can be obtained and maintained more easily in C. elegans. Combining this method with various C. elegans mutants can clarify the molecular mechanisms of axonal transport and IFT.

  15. Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

    Science.gov (United States)

    Kirienko, Natalia V; Cezairliyan, Brent O; Ausubel, Frederick M; Powell, Jennifer R

    2014-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the interaction between bacterial pathogens such as Pseudomonas aeruginosa and the metazoan innate immune system. Powerful genetic and molecular tools in both C. elegans and P. aeruginosa facilitate the identification and analysis of bacterial virulence factors as well as host defense factors. Here we describe three different assays that use the C. elegans-P. aeruginosa strain PA14 host-pathogen system. Fast Killing is a toxin-mediated death that depends on a diffusible toxin produced by PA14 but not on live bacteria. Slow Killing is due to an active infection in which bacteria colonize the C. elegans intestinal lumen. Liquid Killing is designed for high-throughput screening of chemical libraries for anti-infective compounds. Each assay has unique features and, interestingly, the PA14 virulence factors involved in killing are different in each assay.

  16. Study on screening of anti-predator rhizosphere bacterium against Caenorhabditis elegans and its anti predation mechanism

    Directory of Open Access Journals (Sweden)

    HE Qingling

    2016-08-01

    Full Text Available Althoughmicrobial fertilizer is multi-effect,environmental friendly and long-term efficient,its practical application effect is but decreased for being prey by the other creators living in soil frequently.Many bacterium have developed their mechanisms that expel or kill worms to defend themselves from predators.Screening of anti-predator rhizosphere bacterium helps us to find out competitive plant growth promoting rhizobacteria(PGPR.Using Caenorhabditis elegans as sample,this study roughly observed two strains of biocontrol:Pseudomonas aurantiaca JD37 and Pseudomonas fluorescens P13.Using Escherichia coli OP50 as control group,we find the preference order of worms,from highest to lowest,is P13,OP50 and JD37.In slow killing assay,the death rate of worms for JD37 and P13 are 26.12% and 18.66% respectively.The activity and reproduction rate of C.elegans decrease when it is fed on JD37.The results of chemical and micro-biological study show that JD37 cannot produce any currently studied second metabolites which kill worms,while P13 can produce Hydrogen cyanide (HCN.All these results show that JD37 has the ability of anti-predator,and is more competitive under predation pressure,which suggests its broad application prospect as microbial fertilizer.

  17. Energy-based modelling to assess effects of chemicals on Caenorhabditis elegans: a case study on uranium.

    Science.gov (United States)

    Goussen, Benoit; Beaudouin, Rémy; Dutilleul, Morgan; Buisset-Goussen, Adeline; Bonzom, Jean-Marc; Péry, Alexandre R R

    2015-02-01

    The ubiquitous free-living nematode Caenorhabditis elegans is a powerful animal model for measuring the evolutionary effects of pollutants which is increasingly used in (eco) toxicological studies. Indeed, toxicity tests with this nematode can provide in a few days data on the whole life cycle. These data can be analysed with mathematical tools such as toxicokinetic-toxicodynamic modelling approaches. In this study, we assessed how a chronic exposure to a radioactive heavy metal (uranium) affects the life-cycle of C. elegans using a mechanistic model. In order to achieve this, we exposed individuals to a range of seven concentrations of uranium. Growth and reproduction were followed daily. These data were analysed with a model for nematodes based on the Dynamic Energy Budget theory, able to handle a wide range of plausible biological parameters values. Parameter estimations were performed using a Bayesian framework. Our results showed that uranium affects the assimilation of energy from food with a no-effect concentration (NEC) of 0.42 mM U which would be the threshold for effects on both growth and reproduction. The sensitivity analysis showed that the main contributors to the model output were parameters linked to the feeding processes and the actual exposure concentration. This confirms that the real exposure concentration should be measured accurately and that the feeding parameters should not be fixed, but need to be reestimated during the parameter estimation process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Gene expression profiling to characterize sediment toxicity – a pilot study using Caenorhabditis elegans whole genome microarrays

    Directory of Open Access Journals (Sweden)

    Reifferscheid Georg

    2009-04-01

    Full Text Available Abstract Background Traditionally, toxicity of river sediments is assessed using whole sediment tests with benthic organisms. The challenge, however, is the differentiation between multiple effects caused by complex contaminant mixtures and the unspecific toxicity endpoints such as survival, growth or reproduction. The use of gene expression profiling facilitates the identification of transcriptional changes at the molecular level that are specific to the bio-available fraction of pollutants. Results In this pilot study, we exposed the nematode Caenorhabditis elegans to three sediments of German rivers with varying (low, medium and high levels of heavy metal and organic contamination. Beside chemical analysis, three standard bioassays were performed: reproduction of C. elegans, genotoxicity (Comet assay and endocrine disruption (YES test. Gene expression was profiled using a whole genome DNA-microarray approach to identify overrepresented functional gene categories and derived cellular processes. Disaccharide and glycogen metabolism were found to be affected, whereas further functional pathways, such as oxidative phosphorylation, ribosome biogenesis, metabolism of xenobiotics, aging and several developmental processes were found to be differentially regulated only in response to the most contaminated sediment. Conclusion This study demonstrates how ecotoxicogenomics can identify transcriptional responses in complex mixture scenarios to distinguish different samples of river sediments.

  19. Caenorhabditis elegans as a model to study the impact of exposure to light emitting diode (LED) domestic lighting.

    Science.gov (United States)

    Abdel-Rahman, Fawzia; Okeremgbo, Bethel; Alhamadah, Fatimah; Jamadar, Sakha; Anthony, Kevin; Saleh, Mahmoud A

    2017-04-16

    This study aimed to investigate the biological impact of exposure on domestic light emitting diodes (LED) lighting using the free-living nematode Caenorhabditis elegans as a model. Nematodes were separately exposed to white LED light covering the range of 380-750 nm, blue light at 450 nm and black light at 380-420 nm for one life cycle (egg to adult) with dark exposure as the control. Each light range induced stress to the nematode C. elegans such as reducing the number of the hatched eggs and/or delayed the maturation of the hatched eggs to the adult stage. In addition, it lowered or prevented the ability of adults to lay eggs and impaired the locomotion in the exposed worms. The observed type of biological stress was also associated with the production of reactive oxygen species (ROS) as compared to nematodes grown in the dark. It is concluded that the blue light component of white LED light may cause health problems, and further investigation is required to test commercial brands of white LEDs that emit different amounts of blue light.

  20. The model Caenorhabditis elegans in diabetes mellitus and Alzheimer's disease.

    Science.gov (United States)

    Morcos, Michael; Hutter, Harald

    2009-01-01

    Diabetes mellitus, with its complications, and Alzheimer's disease (AD) share many similarities. Both are age-related and associated with enhanced formation of advanced glycation endproducts (AGEs) and oxidative stress, factors that can be observed during the normal aging process as well. AGE deposits can be found in areas of atherosclerotic lesions in diabetes and in senile plaques and neurofibrillary tangles in AD. A classical model organism in aging research is the nematode Caenorhabditis elegans (C. elegans). Though C. elegans lacks a vascular system, it has been introduced in diabetes and AD research since it shares many similarities at the molecular level to pathological processes found in humans. AGEs accumulate in C. elegans, and increased AGE-formation and mitochondrial AGE-modification are responsible for increased oxidative stress and limiting life span. Moreover, C. elegans has an accessible and well characterized nervous system and features several genes homologous to human genes implicated in AD like amyloid-beta protein precursor, presenilins and tau. In addition, human genes linked to AD, such as amyloid-beta or tau, can be expressed and studied in C. elegans. So far, C. elegans research has contributed to a better understanding of the function of AD-related genes and the development of this disease.

  1. Longevity and stress in Caenorhabditis elegans

    Science.gov (United States)

    Zhou, Katherine I.; Pincus, Zachary; Slack, Frank J.

    2011-01-01

    It has long been understood that many of the same manipulations that increase longevity in Caenorhabditis elegans also increase resistance to various acute stressors, and vice-versa; moreover these findings hold in more complex organisms as well. Nevertheless, the mechanistic relationship between these phenotypes remains unclear, and in many cases the overlap between stress resistance and longevity is inexact. Here we review the known connections between stress resistance and longevity, discuss instances in which these connections are absent, and summarize the theoretical explanations that have been posited for these phenomena. PMID:21937765

  2. 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.

  3. A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

    Science.gov (United States)

    Corsi, Ann K; Wightman, Bruce; Chalfie, Martin

    2015-06-01

    A little over 50 years ago, Sydney Brenner had the foresight to develop the nematode (round worm) Caenorhabditis elegans as a genetic model for understanding questions of developmental biology and neurobiology. Over time, research on C. elegans has expanded to explore a wealth of diverse areas in modern biology including studies of the basic functions and interactions of eukaryotic cells, host-parasite interactions, and evolution. C. elegans has also become an important organism in which to study processes that go awry in human diseases. This primer introduces the organism and the many features that make it an outstanding experimental system, including its small size, rapid life cycle, transparency, and well-annotated genome. We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research. Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell. These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues. Copyright © 2015 Corsi, Wightman, and Chalfie.

  4. A Transparent Window into Biology: A Primer on Caenorhabditis elegans

    Science.gov (United States)

    Corsi, Ann K.; Wightman, Bruce; Chalfie, Martin

    2015-01-01

    A little over 50 years ago, Sydney Brenner had the foresight to develop the nematode (round worm) Caenorhabditis elegans as a genetic model for understanding questions of developmental biology and neurobiology. Over time, research on C. elegans has expanded to explore a wealth of diverse areas in modern biology including studies of the basic functions and interactions of eukaryotic cells, host–parasite interactions, and evolution. C. elegans has also become an important organism in which to study processes that go awry in human diseases. This primer introduces the organism and the many features that make it an outstanding experimental system, including its small size, rapid life cycle, transparency, and well-annotated genome. We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research. Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell. These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues. PMID:26088431

  5. 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

  6. Caenorhabditis elegans: A Genetic Guide to Parasitic Nematode Biology.

    Science.gov (United States)

    Bird, D M; Opperman, C H

    1998-09-01

    The advent of parasite genome sequencing projects, as well as an increase in biology-directed gene discovery, promises to reveal genes encoding many of the key molecules required for nematode-host interactions. However, distinguishing parasitism genes from those merely required for nematode viability remains a substantial challenge. Although this will ultimately require a functional test in the host or parasite, the free-living nematode Caenorhabditis elegans can be exploited as a heterologous system to determine function of candidate parasitism genes. Studies of C. elegans also have revealed genetic networks, such as the dauer pathway, that may also be important adaptations for parasitism. As a more directed means of identifying parasitism traits, we developed classical genetics for Heterodera glycines and have used this approach to map genes conferring host resistance-breaking phenotypes. It is likely that the C. elegans and H. glycines genomes will be at least partially syntenic, thus permitting predictive physical mapping of H. glycines genes of interest.

  7. Utilization of Caenorhabditis elegans in laboratory teaching of genetics.

    Science.gov (United States)

    Ma, Xiao-Ying; Zhao, Ying-Lan; Jia, Fang-Xing; Song, Ya-Kun; Xie, Yu-Cong

    2017-08-20

    Caenorhabditis elegans is one of the most important model organisms in the study of biology. It is ideal for laboratory teaching due to its short life cycle and low cost. It enriches the teaching content and can motivate students' interest of learning. In this article, we have shown cased C. elegans for the observation of life cycle and mating, as well as the investigation of single nucleotide polymorphism (SNP) and RNA interfere. In addition, we also discuss the details of the experimental design, basic requirement, preparations and related information. We conclude that C. elegans can be used as the experimental materials for teaching college laboratory courses, such as genetic, cell biology, model biology and developmental biology.

  8. 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.

  9. 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…

  10. 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.

  11. 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

  12. Caenorhabditis elegans intersectin: a synaptic protein regulating neurotransmission

    DEFF Research Database (Denmark)

    Rose, Simon; Malabarba, Maria Grazia; Krag, Claudia

    2007-01-01

    the characterization of intersectin function in Caenorhabditis elegans. Nematode intersectin (ITSN-1) is expressed in the nervous system, and it is enriched in presynaptic regions. The C. elegans intersectin gene (itsn-1) is nonessential for viability. In addition, itsn-1-null worms do not display any evident...

  13. 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...

  14. The RNAi Inheritance Machinery of Caenorhabditis elegans.

    Science.gov (United States)

    Spracklin, George; Fields, Brandon; Wan, Gang; Becker, Diveena; Wallig, Ashley; Shukla, Aditi; Kennedy, Scott

    2017-07-01

    Gene silencing mediated by dsRNA (RNAi) can persist for multiple generations in Caenorhabditis elegans (termed RNAi inheritance). Here we describe the results of a forward genetic screen in C. elegans that has identified six factors required for RNAi inheritance: GLH-1/VASA, PUP-1/CDE-1, MORC-1, SET-32, and two novel nematode-specific factors that we term here (heritable RNAi defective) HRDE-2 and HRDE-4 The new RNAi inheritance factors exhibit mortal germline (Mrt) phenotypes, which we show is likely caused by epigenetic deregulation in germ cells. We also show that HRDE-2 contributes to RNAi inheritance by facilitating the binding of small RNAs to the inheritance Argonaute (Ago) HRDE-1 Together, our results identify additional components of the RNAi inheritance machinery whose conservation provides insights into the molecular mechanism of RNAi inheritance, further our understanding of how the RNAi inheritance machinery promotes germline immortality, and show that HRDE-2 couples the inheritance Ago HRDE-1 with the small RNAs it needs to direct RNAi inheritance and germline immortality. Copyright © 2017 by the Genetics Society of America.

  15. Fucoxanthin increases lifespan of Drosophila melanogaster and Caenorhabditis elegans.

    Science.gov (United States)

    Lashmanova, Ekaterina; Proshkina, Ekaterina; Zhikrivetskaya, Svetlana; Shevchenko, Oksana; Marusich, Elena; Leonov, Sergey; Melerzanov, Alex; Zhavoronkov, Alex; Moskalev, Alexey

    2015-10-01

    The pharmacological activation of stress-defense mechanisms is one of the perspective ways to increase human lifespan. The goal of the present study was to study the effects on lifespan of Drosophila melanogaster and Caenorhabditis elegans of two carotenoids: ß-carotene and fucoxanthin, which are bioactive natural substances in human diet. In addition, the effects of carotenoids on the flies survival were studied under stress conditions, including starvation, thermal stress (35°C), oxidative stress (20 mM paraquat), as well as locomotor activity, fecundity, and genes expression level. Our results demonstrated lifespan extension of flies by both carotenoids. However, the positive effects on the lifespan of C. elegans were revealed only for fucoxanthin. In presence of carotenoids decreased flies' fecundity, increased spontaneous locomotor activity and resistance to oxidative stress were detected. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. The Sexual Dimorphism of Dietary Restriction Responsiveness in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Sakiko Honjoh

    2017-12-01

    Full Text Available Organismal lifespan is highly plastic in response to environmental cues, and dietary restriction (DR is the most robust way to extend lifespan in various species. Recent studies have shown that sex also is an important factor for lifespan regulation; however, it remains largely unclear how these two factors, food and sex, interact in lifespan regulation. The nematode Caenorhabditis elegans has two sexes, hermaphrodite and male, and only the hermaphrodites are essential for the short-term succession of the species. Here, we report an extreme sexual dimorphism in the responsiveness to DR in C. elegans; the essential hermaphrodites show marked longevity responses to various forms of DR, but the males show few longevity responses and sustain reproductive ability. Our analysis reveals that the sex determination pathway and the steroid hormone receptor DAF-12 regulate the sex-specific DR responsiveness, integrating sex and environmental cues to determine organismal lifespan.

  17. Noncanonical cell death in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Kinet, Maxime J; Shaham, Shai

    2014-01-01

    The nematode Caenorhabditis elegans has served as a fruitful setting for cell death research for over three decades. A conserved pathway of four genes, egl-1/BH3-only, ced-9/Bcl-2, ced-4/Apaf-1, and ced-3/caspase, coordinates most developmental cell deaths in C. elegans. However, other cell death forms, programmed and pathological, have also been described in this animal. Some of these share morphological and/or molecular similarities with the canonical apoptotic pathway, while others do not. Indeed, recent studies suggest the existence of an entirely novel mode of programmed developmental cell destruction that may also be conserved beyond nematodes. Here, we review evidence for these noncanonical pathways. We propose that different cell death modalities can function as backup mechanisms for apoptosis, or as tailor-made programs that allow specific dying cells to be efficiently cleared from the animal. © 2014 Elsevier Inc. All rights reserved.

  18. 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.

  19. Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

    Science.gov (United States)

    Cezairliyan, Brent; Vinayavekhin, Nawaporn; Grenfell-Lee, Daniel; Yuen, Grace J; Saghatelian, Alan; Ausubel, Frederick M

    2013-01-01

    Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches.

  20. 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. PMID:22966416

  1. Identification of Pseudomonas aeruginosa phenazines that kill Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Brent Cezairliyan

    2013-01-01

    Full Text Available Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches.

  2. Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

    Science.gov (United States)

    Cezairliyan, Brent; Vinayavekhin, Nawaporn; Grenfell-Lee, Daniel; Yuen, Grace J.; Saghatelian, Alan; Ausubel, Frederick M.

    2013-01-01

    Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches. PMID:23300454

  3. ROS in Aging Caenorhabditis elegans: Damage or Signaling?

    Directory of Open Access Journals (Sweden)

    Patricia Back

    2012-01-01

    Full Text Available 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.

  4. 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. © 2015 Hutter and Moerman. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  5. An imaging and analysis toolset for the study of Caenorhabditis elegans neurodevelopment

    Science.gov (United States)

    Christensen, Ryan; Bokinsky, Alexandra; Santella, Anthony; Wu, Yicong; Marquina, Javier; Kovacevic, Ismar; Kumar, Abhishek; Winter, Peter; McCreedy, Evan; Mohler, William; Bao, Zhirong; Colón-Ramos, Daniel; Shroff, Hari

    2015-03-01

    How an entire nervous system develops remains mysterious. We have developed a light-sheet microscope system to examine neurodevelopment in C. elegans embryos. Our system creates overlapping light sheets from two orthogonally positioned objectives, enabling imaging from the first cell division to hatching (~14 hours) with 350 nm isotropic resolution. We have also developed computer algorithms to computationally straighten nematode embryos, facilitating data comparison and combination from multiple animals. We plan to use these tools to create an atlas showing the position and morphology of all neurons in the developing embryo.

  6. Inhibition of quorum-sensing-controlled virulence factors of Pseudomonas aeruginosa by Murraya koenigii essential oil: a study in a Caenorhabditis elegans infectious model.

    Science.gov (United States)

    Ganesh, P Sankar; Rai, Ravishankar Vittal

    2016-12-01

    The global emergence of antibiotic-resistant strains of Pseudomonas aeruginosa poses a major threat in both hospital environments and the community. P. aeruginosa is an opportunistic human pathogen, and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation, which are crucial for establishment of the infection. Expression of many virulence factors such as pyocyanin and proteases in P. aeruginosa is under the control of the QS system, and are mediated by small molecules such as acyl homoserine lactones. Thus, interfering with the QS system would provide alternative ways of controlling the pathogenicity. Murraya koenigii is a medicinal plant widely used in India. The present study investigated the in vivo inhibitory activity of M. koenigii essential oil (EO) on QS-controlled virulence factors of P. aeruginosa PAO1 using C. elegans. M. koenigii EO significantly inhibited the pyocyanin production and staphylolytic LasA activity of P. aeruginosa PAO1. As compared to the control group with 100 % killing of C. elegans, M. koenigii EO was able to rescue an average of 60 % of C. elegans from death due to the toxic effect of P. aeruginosa. Thus, the present study suggests the anti-QS potential of M. koenigii EO which therefore can be considered as a future therapeutic agent for management of P. aeruginosa-mediated infections.

  7. Sorbus alnifolia protects dopaminergic neurodegeneration in Caenorhabditis elegans.

    Science.gov (United States)

    Cheon, Se-Myeong; Jang, Insoo; Lee, Myon-Hee; Kim, Dae Keun; Jeon, Hoon; Cha, Dong Seok

    2017-12-01

    The twigs of Sorbus alnifolia (Sieb. et Zucc.) K. Koch (Rosaceae) have been used to treat neurological disorders as a traditional medicine in Korea. However, there are limited data describing the efficacy of S. alnifolia in Parkinson's disease (PD). This study was conducted to identify the protective effects of the methanol extracts of S. alnifolia (MESA) on the dopaminergic (DA) neurodegeneration in Caenorhabditis elegans. To test the neuroprotective action of MESA, viability assay was performed after 48 h exposure to 1-methyl-4-phenylpyridine (MMP+) in PC12 cells and C. elegans (400 μM and 2 mM of MMP+, respectively). Fluorescence intensity was quantified using transgenic mutants such as BZ555 (Pdat-1::GFP) and and UA57 (Pdat-1::GFP and Pdat-1::CAT-2) to determine MESA's effects on DA neurodegeneration in C. elegans. Aggregation of α-synuclein was observed using NL5901 strain (unc-54p::α-synuclein::YFP). MESA's protective effects on the DA neuronal functions were examined by food-sensing assay. Lifespan assay was conducted to test the effects of MESA on the longevity. MESA restored MPP+-induced loss of viability in both PC12 cells and C. elegans (85.8% and 54.9%, respectively). In C. elegans, MESA provided protection against chemically and genetically-induced DA neurodegeneration, respectively. Moreover, food-sensing functions were increased 58.4% by MESA in the DA neuron degraded worms. MESA also prolonged the average lifespan by 25.6%. However, MESA failed to alter α-synuclein aggregation. These results revealed that MESA protects DA neurodegeneration and recovers diminished DA neuronal functions, thereby can be a valuable candidate for the treatment of PD.

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

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    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.

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

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    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.

  10. 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...

  11. Identification and analysis of internal promoters in Caenorhabditis elegans operons.

    Science.gov (United States)

    Huang, Peiming; Pleasance, Erin D; Maydan, Jason S; Hunt-Newbury, Rebecca; O'Neil, Nigel J; Mah, Allan; Baillie, David L; Marra, Marco A; Moerman, Donald G; Jones, Steven J M

    2007-10-01

    The current Caenorhabditis elegans genomic annotation has many genes organized in operons. Using directionally stitched promoterGFP methodology, we have conducted the largest survey to date on the regulatory regions of annotated C. elegans operons and identified 65, over 25% of those studied, with internal promoters. We have termed these operons "hybrid operons." GFP expression patterns driven from internal promoters differ in tissue specificity from expression of operon promoters, and serial analysis of gene expression data reveals that there is a lack of expression correlation between genes in many hybrid operons. The average length of intergenic regions with putative promoter activity in hybrid operons is larger than previous estimates for operons as a whole. Genes with internal promoters are more commonly involved in gene duplications and have a significantly lower incidence of alternative splicing than genes without internal promoters, although we have observed almost all trans-splicing patterns in these two distinct groups. Finally, internal promoter constructs are able to rescue lethal knockout phenotypes, demonstrating their necessity in gene regulation and survival. Our work suggests that hybrid operons are common in the C. elegans genome and that internal promoters influence not only gene organization and expression but also operon evolution.

  12. Nucleotide Excision Repair in Caenorhabditis elegans

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    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.

  13. [CRISPR-Cas9 mediated genome editing in Caenorhabditis elegans].

    Science.gov (United States)

    Meng, Xi'nan; Zhou, Hengda; Xu, Suhong

    2017-10-25

    The development of genome editing techniques based on CRISPR (Clustered regularly interspaced short palindromic repeats)-Cas9 system has revolutionized biomedical researches. It can be utilized to edit genome sequence in almost any organisms including Caenorhabditis elegans, one of the most convenient and classic genetic model animals. The application of CRISPR-Cas9 mediated genome editing in C. elegans promotes the functional analysis of gene and proteins under many physiological conditions. In this mini-review, we summarized the development of CRISPR-Cas9-based genome editing in C. elegans.

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

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    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.

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

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    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…

  16. 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...

  17. Caenorhabditis elegans neuromuscular junction: GABA receptors and ivermectin action.

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    Guillermina Hernando

    Full Text Available The prevalence of human and animal helminth infections remains staggeringly high, thus urging the need for concerted efforts towards this area of research. GABA receptors, encoded by the unc-49 gene, mediate body muscle inhibition in Caenorhabditis elegans and parasitic nematodes and are targets of anthelmintic drugs. Thus, the characterization of nematode GABA receptors provides a foundation for rational anti-parasitic drug design. We therefore explored UNC-49 channels from C. elegans muscle cultured cells of the first larval stage at the electrophysiological and behavioral levels. Whole-cell recordings reveal that GABA, muscimol and the anthelmintic piperazine elicit macroscopic currents from UNC-49 receptors that decay in their sustained presence, indicating full desensitization. Single-channel recordings show that all drugs elicit openings of ∼2.5 pA (+100 mV, which appear either as brief isolated events or in short bursts. The comparison of the lowest concentration required for detectable channel opening, the frequency of openings and the amplitude of macroscopic currents suggest that piperazine is the least efficacious of the three drugs. Macroscopic and single-channel GABA-activated currents are profoundly and apparently irreversibly inhibited by ivermectin. To gain further insight into ivermectin action at C. elegans muscle, we analyzed its effect on single-channel activity of the levamisol-sensitive nicotinic receptor (L-AChR, the excitatory receptor involved in neuromuscular transmission. Ivermectin produces a profound inhibition of the frequency of channel opening without significant changes in channel properties. By revealing that ivermectin inhibits C. elegans muscle GABA and L-AChR receptors, our study adds two receptors to the already known ivermectin targets, thus contributing to the elucidation of its pleiotropic effects. Behavioral assays in worms show that ivermectin potentiates piperazine-induced paralysis, thus suggesting

  18. Chemistry and the worm: Caenorhabditis elegans as a platform for integrating chemical and biological research.

    Science.gov (United States)

    Hulme, S Elizabeth; Whitesides, George M

    2011-05-16

    This Review discusses the potential usefulness of the worm Caenorhabditis elegans as a model organism for chemists interested in studying living systems. C. elegans, a 1 mm long roundworm, is a popular model organism in almost all areas of modern biology. The worm has several features that make it attractive for biology: it is small (biology, the Review provides examples of current research with C. elegans that is chemically relevant. It also describes tools-biological, chemical, and physical-that are available to researchers studying the worm. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Neurobiology of Caenorhabditis elegans Locomotion: Where Do We Stand?

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    Gjorgjieva, Julijana; Biron, David; Haspel, Gal

    2014-01-01

    Animals use a nervous system for locomotion in some stage of their life cycle. The nematode Caenorhabditis elegans, a major animal model for almost all fields of experimental biology, has long been used for detailed studies of genetic and physiological locomotion mechanisms. Of its 959 somatic cells, 302 are neurons that are identifiable by lineage, location, morphology, and neurochemistry in every adult hermaphrodite. Of those, 75 motoneurons innervate body wall muscles that provide the thrust during locomotion. In this Overview, we concentrate on the generation of either forward- or backward-directed motion during crawling and swimming. We describe locomotion behavior, the parts constituting the locomotion system, and the relevant neuronal connectivity. Because it is not yet fully understood how these components combine to generate locomotion, we discuss competing hypotheses and models. PMID:26955070

  20. Forward and reverse genetics approaches to uncover metabolic aging pathways in Caenorhabditis elegans

    NARCIS (Netherlands)

    Gao, Arwen W.; Bos, uit de Jelmi; Sterken, Mark G.; Kammenga, Jan E.; Smith, Reuben L.; Houtkooper, Riekelt H.

    2017-01-01

    The biological mechanisms of aging have been studied in depth and prominent findings in this field promote the development of new therapies for age-associated disorders. Various model organisms are used for research on aging; among these, the nematode Caenorhabditis elegans has been widely used and

  1. Cerium oxide nanoparticle aggregates affect stress response and function in Caenorhabditis elegans

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    Steven Rogers

    2015-03-01

    Full Text Available Objective: The continual increase in production and disposal of nanomaterials raises concerns regarding the safety of nanoparticles on the environmental and human health. Recent studies suggest that cerium oxide (CeO2 nanoparticles may possess both harmful and beneficial effects on biological processes. The primary objective of this study is to evaluate how exposure to different concentrations (0.17–17.21 µg/mL of aggregated CeO2 nanoparticles affects indices of whole animal stress and survivability in Caenorhabditis elegans. Methods: Caenorhabditis elegans were exposed to different concentrations of CeO2 nanoparticles and evaluated. Results: Our findings demonstrate that chronic exposure of CeO2 nanoparticle aggregates is associated with increased levels of reactive oxygen species and heat shock stress response (HSP-4 in Caenorhabditis elegans, but not mortality. Conversely, CeO2 aggregates promoted strain-dependent decreases in animal fertility, a decline in stress resistance as measured by thermotolerance, and shortened worm length. Conclusion: The data obtained from this study reveal the sublethal toxic effects of CeO2 nanoparticle aggregates in Caenorhabditis elegans and contribute to our understanding of how exposure to CeO2 may affect the environment.

  2. Evaluation of pesticide toxicities with differing mechanisms using Caenorhabditis elegans.

    Science.gov (United States)

    Ruan, Qin-Li; Ju, Jing-Juan; Li, Yun-Hui; Liu, Ran; Pu, Yue-Pu; Yin, Li-Hong; Wang, Da-Yong

    2009-01-01

    The aim of this study was to (1) determine whether model organism Caenorhabditis elegans was sensitive to pesticides at the maximum concentration limits regulated by national agency standards, and (2) examine the multi-biological toxicities occurring as a result of exposure to pesticides. Five pesticides, namely, chlorpyrifos, imibacloprid, buprofezin, cyhalothrin, and glyphosate, with four different mechanisms of action were selected for the investigation. In accordance with national agency requirements, 4 exposed groups were used for each tested pesticide with the concentration scales ranging from 1.0 x 10(-3) to 1 mg/L. L4 larvae were exposed for 24 and 72 h, respectively. Endpoints of locomotion, propagation, and development were selected for the assay as parameters of toxicity. After exposure for 24 h, both the body bend frequency and head thrash frequency of nematodes exposed to chlorpyrifos, imibacloprid, and cyhalothrin decreased in a concentration-dependent manner, and there were significant differences between exposed groups at maximum concentration level (MCL) compared to control. The generation time of nematodes exposed to buprofezin 24 h significantly increased in a concentration-dependent manner in the highest exposed group. When exposed for 72 h, the body bend frequency and head thrash frequency of nematodes exposed to cyhalothrin markedly decreased at MCL. The generation time and brood size of nematodes exposed to buprofezin were reduced in a concentration-dependent manner. The behavior of nematodes was sensitive to pesticides with neurotoxic properties, while pesticides affecting insect growth modified the reproductive system. The effects of pesticides on nematodes exposed for 24 h appeared more sensitive than with exposure for 72 h. Caenorhabditis elegans may thus be used for assessing the adverse effects of pesticide residues in aquatic environment.

  3. Benzofuran-chalcone hybrids as potential multifunctional agents against Alzheimer's disease: synthesis and in vivo studies with transgenic Caenorhabditis elegans.

    Science.gov (United States)

    Sashidhara, Koneni V; Modukuri, Ram K; Jadiya, Pooja; Dodda, Ranga Prasad; Kumar, Manoj; Sridhar, Balasubramaniam; Kumar, Vikash; Haque, Rizwanul; Siddiqi, Mohammad Imran; Nazir, Aamir

    2014-12-01

    In the search for effective multifunctional agents for the treatment of Alzheimer's disease (AD), a series of novel hybrids incorporating benzofuran and chalcone fragments were designed and synthesized. These hybrids were screened by using a transgenic Caenorhabditis elegans model that expresses the human β-amyloid (Aβ) peptide. Among the hybrids investigated, (E)-3-(7-methyl-2-(4-methylbenzoyl)benzofuran-5-yl)-1-phenylprop-2-en-1-one (4 f), (E)-3-(2-benzoyl-7-methylbenzofuran-5-yl)-1-phenylprop-2-en-1-one (4 i), and (E)-3-(2-benzoyl-7-methylbenzofuran-5-yl)-1-(thiophen-2-yl)prop-2-en-1-one (4 m) significantly decreased Aβ aggregation and increased acetylcholine (ACh) levels along with the overall availability of ACh at the synaptic junction. These compounds were also found to decrease acetylcholinesterase (AChE) levels, reduce oxidative stress in the worms, lower lipid content, and to provide protection against chemically induced cholinergic neurodegeneration. Overall, the multifunctional effects of these hybrids qualify them as potential drug leads for further development in AD therapy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. 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.

  5. The ubiquitin proteasome system in Caenorhabditis elegans and its regulation☆

    Science.gov (United States)

    Papaevgeniou, Nikoletta; Chondrogianni, Niki

    2014-01-01

    Protein degradation constitutes a major cellular function that is responsible for maintenance of the normal cellular physiology either through the degradation of normal proteins or through the elimination of damaged proteins. The Ubiquitin–Proteasome System (UPS)1 is one of the main proteolytic systems that orchestrate protein degradation. Given that up- and down- regulation of the UPS system has been shown to occur in various normal (such as ageing) and pathological (such as neurodegenerative diseases) processes, the exogenous modulation of the UPS function and activity holds promise of (a) developing new therapeutic interventions against various diseases and (b) establishing strategies to maintain cellular homeostasis. Since the proteasome genes are evolutionarily conserved, their role can be dissected in simple model organisms, such as the nematode, Caenorhabditis elegans. In this review, we survey findings on the redox regulation of the UPS in C. elegans showing that the nematode is an instrumental tool in the identification of major players in the UPS pathway. Moreover, we specifically discuss UPS-related genes that have been modulated in the nematode and in human cells and have resulted in similar effects thus further exhibiting the value of this model in the study of the UPS. PMID:24563851

  6. PRMT-5 converts monomethylarginines into symmetrical dimethylarginines in Caenorhabditis elegans.

    Science.gov (United States)

    Kanou, Akihiko; Kako, Koichiro; Hirota, Keiko; Fukamizu, Akiyoshi

    2017-02-01

    The transmethylation to arginine residues of proteins is catalyzed by protein arginine methyltransferases (PRMTs) that form monomethylarginine (MMA), asymmetric (ADMA) and symmetric dimethylarginines (SDMA). Although we previously demonstrated that the generation of ADMA residues in whole proteins is driven by PRMT-1 in Caenorhabditis elegans, much less is known about MMA and SDMA in vivo. In this study, we measured the amounts of different methylarginines in whole protein extracts made from wild-type (N2) C. elegans and from prmt-1 and prmt-5 null mutants using liquid chromatography-tandem mass spectrometry. Interestingly, we found that the amounts of MMA and SDMA are about fourfold higher than those of ADMA in N2 protein lysates using acid hydrolysis. We were unable to detect SDMA residues in the prmt-5 null mutant. In comparison with N2, an increase in SDMA and decrease in MMA were observed in prmt-1 mutant worms with no ADMA, but ADMA and MMA levels were unchanged in prmt-5 mutant worms. These results suggest that PRMT-1 contributes, at least in part, to MMA production, but that PRMT-5 catalyzes the symmetric dimethylation of substrates containing MMA residues in vivo.

  7. Selenium induces cholinergic motor neuron degeneration in Caenorhabditis elegans.

    Science.gov (United States)

    Estevez, Annette O; Mueller, Catherine L; Morgan, Kathleen L; Szewczyk, Nathaniel J; Teece, Luke; Miranda-Vizuete, Antonio; Estevez, Miguel

    2012-10-01

    Selenium is an essential micronutrient required for cellular antioxidant systems, yet at higher doses it induces oxidative stress. Additionally, in vertebrates environmental exposures to toxic levels of selenium can cause paralysis and death. Here we show that selenium-induced oxidative stress leads to decreased cholinergic signaling and degeneration of cholinergic neurons required for movement and egg-laying in Caenorhabditis elegans. Exposure to high levels of selenium leads to proteolysis of a soluble muscle protein through mechanisms suppressible by two pharmacological agents, levamisole and aldicarb which enhance cholinergic signaling in muscle. In addition, animals with reduction-of-function mutations in genes encoding post-synaptic levamisole-sensitive acetylcholine receptor subunits or the vesicular acetylcholine transporter developed impaired forward movement faster during selenium-exposure than normal animals, again confirming that selenium reduces cholinergic signaling. Finally, the antioxidant reduced glutathione, inhibits selenium-induced reductions in egg-laying through a cellular protective mechanism dependent on the C. elegans glutaredoxin, GLRX-21. These studies provide evidence that the environmental toxicant selenium induces neurodegeneration of cholinergic neurons through depletion of glutathione, a mechanism linked to the neuropathology of Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. 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. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

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

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    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.

  10. Effects of sterols on the development and aging of caenorhabditis elegans

    Science.gov (United States)

    Because Caenorhabditis elegans lacks several components of the de novo sterol biosynthesis pathway, it requires sterols as essential nutrients. Supplemented cholesterol undergoes extensive enzymatic modification in C. elegans to form other sterols of unknown function. Because sterol metabolism in ...

  11. Cas9 Variants Expand the Target Repertoire in Caenorhabditis elegans.

    Science.gov (United States)

    Bell, Ryan T; Fu, Becky X H; Fire, Andrew Z

    2016-02-01

    The proliferation of CRISPR/Cas9-based methods in Caenorhabditis elegans has enabled efficient genome editing and precise genomic tethering of Cas9 fusion proteins. Experimental designs using CRISPR/Cas9 are currently limited by the need for a protospacer adjacent motif (PAM) in the target with the sequence NGG. Here we report the characterization of two modified Cas9 proteins in C. elegans that recognize NGA and NGCG PAMs. We found that each variant could stimulate homologous recombination with a donor template at multiple loci and that PAM specificity was comparable to that of wild-type Cas9. To directly compare effectiveness, we used CRISPR/Cas9 genome editing to generate a set of assay strains with a common single-guide RNA (sgRNA) target sequence, but that differ in the juxtaposed PAM (NGG, NGA, or NGCG). In this controlled setting, we determined that the NGA PAM Cas9 variant can be as effective as wild-type Cas9. We similarly edited a genomic target to study the influence of the base following the NGA PAM. Using four strains with four NGAN PAMs differing only at the fourth position and adjacent to the same sgRNA target, we observed that efficient homologous replacement was attainable with any base in the fourth position, with an NGAG PAM being the most effective. In addition to demonstrating the utility of two Cas9 mutants in C. elegans and providing reagents that permit CRISPR/Cas9 experiments with fewer restrictions on potential targets, we established a means to benchmark the efficiency of different Cas9::PAM combinations that avoids variations owing to differences in the sgRNA sequence. Copyright © 2016 by the Genetics Society of America.

  12. Cas9 Variants Expand the Target Repertoire in Caenorhabditis elegans

    Science.gov (United States)

    Bell, Ryan T.; Fu, Becky X. H.; Fire, Andrew Z.

    2016-01-01

    The proliferation of CRISPR/Cas9-based methods in Caenorhabditis elegans has enabled efficient genome editing and precise genomic tethering of Cas9 fusion proteins. Experimental designs using CRISPR/Cas9 are currently limited by the need for a protospacer adjacent motif (PAM) in the target with the sequence NGG. Here we report the characterization of two modified Cas9 proteins in C. elegans that recognize NGA and NGCG PAMs. We found that each variant could stimulate homologous recombination with a donor template at multiple loci and that PAM specificity was comparable to that of wild-type Cas9. To directly compare effectiveness, we used CRISPR/Cas9 genome editing to generate a set of assay strains with a common single-guide RNA (sgRNA) target sequence, but that differ in the juxtaposed PAM (NGG, NGA, or NGCG). In this controlled setting, we determined that the NGA PAM Cas9 variant can be as effective as wild-type Cas9. We similarly edited a genomic target to study the influence of the base following the NGA PAM. Using four strains with four NGAN PAMs differing only at the fourth position and adjacent to the same sgRNA target, we observed that efficient homologous replacement was attainable with any base in the fourth position, with an NGAG PAM being the most effective. In addition to demonstrating the utility of two Cas9 mutants in C. elegans and providing reagents that permit CRISPR/Cas9 experiments with fewer restrictions on potential targets, we established a means to benchmark the efficiency of different Cas9::PAM combinations that avoids variations owing to differences in the sgRNA sequence. PMID:26680661

  13. Forces applied during classical touch assays for Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Adam L Nekimken

    Full Text Available For decades, Caenorhabditis elegans roundworms have been used to study the sense of touch, and this work has been facilitated by a simple behavioral assay for touch sensation. To perform this classical assay, an experimenter uses an eyebrow hair to gently touch a moving worm and observes whether or not the worm reverses direction. We used two experimental approaches to determine the manner and moment of contact between the eyebrow hair tool and freely moving animals and the forces delivered by the classical assay. Using high-speed video (2500 frames/second, we found that typical stimulus delivery events include a brief moment when the hair is contact with the worm's body and not the agar substrate. To measure the applied forces, we measured forces generated by volunteers mimicking the classical touch assay by touching a calibrated microcantilever. The mean (61 μN and median forces (26 μN were more than ten times higher than the 2-μN force known to saturate the probability of evoking a reversal in adult C. elegans. We also considered the eyebrow hairs as an additional source of variation. The stiffness of the sampled eyebrow hairs varied between 0.07 and 0.41 N/m and was correlated with the free length of hair. Collectively, this work establishes that the classical touch assay applies enough force to saturate the probability of evoking reversals in adult C. elegans in spite of its variability among trials and experimenters and that increasing the free length of the hair can decrease the applied force.

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

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    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.

  15. A Caenorhabditis elegans Mass Spectrometric Resource for Neuropeptidomics

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    Van Bael, Sven; Zels, Sven; Boonen, Kurt; Beets, Isabel; Schoofs, Liliane; Temmerman, Liesbet

    2018-01-01

    Neuropeptides are important signaling molecules used by nervous systems to mediate and fine-tune neuronal communication. They can function as neurotransmitters or neuromodulators in neural circuits, or they can be released as neurohormones to target distant cells and tissues. Neuropeptides are typically cleaved from larger precursor proteins by the action of proteases and can be the subject of post-translational modifications. The short, mature neuropeptide sequences often entail the only evolutionarily reasonably conserved regions in these precursor proteins. Therefore, it is particularly challenging to predict all putative bioactive peptides through in silico mining of neuropeptide precursor sequences. Peptidomics is an approach that allows de novo characterization of peptides extracted from body fluids, cells, tissues, organs, or whole-body preparations. Mass spectrometry, often combined with on-line liquid chromatography, is a hallmark technique used in peptidomics research. Here, we used an acidified methanol extraction procedure and a quadrupole-Orbitrap LC-MS/MS pipeline to analyze the neuropeptidome of Caenorhabditis elegans. We identified an unprecedented number of 203 mature neuropeptides from C. elegans whole-body extracts, including 35 peptides from known, hypothetical, as well as from completely novel neuropeptide precursor proteins that have not been predicted in silico. This set of biochemically verified peptide sequences provides the most elaborate C. elegans reference neurpeptidome so far. To exploit this resource to the fullest, we make our in-house database of known and predicted neuropeptides available to the community as a valuable resource. We are providing these collective data to help the community progress, amongst others, by supporting future differential and/or functional studies.

  16. 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.

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

    OpenAIRE

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

    2015-01-01

    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....

  18. Oleanolic acid activates daf-16 to increase lifespan in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaolong; Lu, Lulu; Zhou, Lijun, E-mail: lijunzhou@tju.edu.cn

    2015-12-25

    Oleanolic acid (OA) is an active ingredient in natural plants. It has been reported to possess a variety of pharmacological activities, but very little is known about its effects of anti-aging. We investigate here whether OA has an impact on longevity in vivo, and more specifically, we have examined effects of OA on the lifespan and stress tolerance in Caenorhabditis elegans (C. elegans). Our results showed that OA could extend the lifespan, increase its stress resistance and reduce the intracellular reactive oxygen species (ROS) in wild-type worms. Moreover, we have found that OA-induced longevity may not be associated with the calorie restriction (CR) mechanism. Our mechanistic studies using daf-16 loss-of-function mutant strains (GR1307) indicated that the extension of lifespan by OA requires daf-16. In addition, OA treatment could also modulate the nuclear localization, and the quantitative real-time PCR results revealed that up-regulation of daf-16 target genes such as sod-3, hsp-16.2 and ctl-1 could prolong lifespan and increase stress response in C. elegans. This study overall uncovers the longevity effect of OA and its underpinning mechanisms. - Graphical abstract: Oleanolic acid modulates the activity of DAF-16 to promote longevity and increase stress resistance in Caenorhabditis elegans. - Highlights: • OA extends the lifespan of wild-type Caenorhabditis elegans. • OA improves the stress resistance and reduces the intracellular ROS level in C. elegans. • OA induces lifespan extension may not proceed through the CR mechanism. • OA extends the lifespan in C. elegans is modulated by daf-16.

  19. 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.

  20. Mating behavior, male sensory cilia, and polycystins in Caenorhabditis elegans.

    Science.gov (United States)

    O'Hagan, Robert; Wang, Juan; Barr, Maureen M

    2014-09-01

    The investigation of Caenorhabditis elegans males and the male-specific sensory neurons required for mating behaviors has provided insight into the molecular function of polycystins and mechanisms that are needed for polycystin ciliary localization. In humans, polycystin 1 and polycystin 2 are needed for kidney function; loss of polycystin function leads to autosomal dominant polycystic kidney disease (ADPKD). Polycystins localize to cilia in C. elegans and mammals, a finding that has guided research into ADPKD. The discovery that the polycystins form ciliary receptors in male-specific neurons needed for mating behaviors has also helped to unlock insights into two additional exciting new areas: the secretion of extracellular vesicles; and mechanisms of ciliary specialization. First, we will summarize the studies done in C. elegans regarding the expression, localization, and function of the polycystin 1 and 2 homologs, LOV-1 and PKD-2, and discuss insights gained from this basic research. Molecules that are co-expressed with the polycystins in the male-specific neurons may identify evolutionarily conserved molecular mechanisms for polycystin function and localization. We will discuss the finding that polycystins are secreted in extracellular vesicles that evoke behavioral change in males, suggesting that such vesicles provide a novel form of communication to conspecifics in the environment. In humans, polycystin-containing extracellular vesicles are secreted in urine and can be taken up by cilia, and quickly internalized. Therefore, communication by polycystin-containing extracellular vesicles may also use mechanisms that are evolutionarily conserved from nematode to human. Lastly, different cilia display structural and functional differences that specialize them for particular tasks, despite the fact that virtually all cilia are built by a conserved intraflagellar transport (IFT) mechanism and share some basic structural features. Comparative analysis of the male

  1. In Vivo Inhibition of Lipid Accumulation in Caenorhabditis elegans

    Science.gov (United States)

    Sulistiyani; Purwakusumah, E. P.; Andrianto, D.

    2017-03-01

    This is a preliminary research report on the use of Caenorhabditis elegans as a model to establish anti-obesity screening assay of the natural plant resources. Nematode C. elegans has been used as experimental animal model for understanding lipid accumulation. The objective of this research was to investigate the effect of selected plant extracts on lipid accumulation in C. elegans. Currently no report could be found regarding lipid accumulation in C.elegans treated with ethanolic leaf extracts of jabon merah (Anthocephalus macrophyllus), jati belanda (Guazuma ulmifolia), and Mindi (Melia Azedarach) plants. Lipid accumulation was determined qualitatively using lipid staining method and quantitatively by colorimetry using sulpho-phospho-vanillin reagent. Data showed that lipid accumulation was inhibited up to 72% by extract of M. azedarach, about 35% by both of A. macrophyllus and G. ulmifolia extracts, and up to 25% by orlistat (a synthetic slimming drug). Ethanolic extract of A. macrophyllus, G. ulmifolia, and M. azedarach leaves were shown to inhibit lipid accumulation in C. elegans and M. azedarach leaves extracts was the most effective inhibitor. C.elegans were shown to be an effective model for in vivo lipid accumulation mechanism and potential to be used as a rapid screening assay for bioactive compounds with lipid accumulation inhibitory activity.

  2. Formation and Regulation of Adaptive Response in Nematode Caenorhabditis elegans

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    Y.-L. Zhao

    2012-01-01

    Full Text Available All organisms respond to environmental stresses (e.g., heavy metal, heat, UV irradiation, hyperoxia, food limitation, etc. with coordinated adjustments in order to deal with the consequences and/or injuries caused by the severe stress. The nematode Caenorhabditis elegans often exerts adaptive responses if preconditioned with low concentrations of agents or stressor. In C. elegans, three types of adaptive responses can be formed: hormesis, cross-adaptation, and dietary restriction. Several factors influence the formation of adaptive responses in nematodes, and some mechanisms can explain their response formation. In particular, antioxidation system, heat-shock proteins, metallothioneins, glutathione, signaling transduction, and metabolic signals may play important roles in regulating the formation of adaptive responses. In this paper, we summarize the published evidence demonstrating that several types of adaptive responses have converged in C. elegans and discussed some possible alternative theories explaining the adaptive response control.

  3. A Caenorhabditis elegans Glycolipid-binding Galectin Functions in Host Defense against Bacterial Infection*

    Science.gov (United States)

    Ideo, Hiroko; Fukushima, Keiko; Gengyo-Ando, Keiko; Mitani, Shohei; Dejima, Katsufumi; Nomura, Kazuya; Yamashita, Katsuko

    2009-01-01

    Galectins are a family of β-galactoside-binding proteins that are widely found among animal species and that regulate diverse biological phenomena. To study the biological function of glycolipid-binding galectins, we purified recombinant Caenorhabditis elegans galectins (LEC-1–11) and studied their binding to C. elegans glycolipids. We found that LEC-8 binds to glycolipids in C. elegans through carbohydrate recognition. It has been reported that Cry5B-producing Bacillus thuringiensis strains can infect C. elegans and that the C. elegans Cry5B receptor molecules are glycolipids. We found that Cry5B and LEC-8 bound to C. elegans glycolipid-coated plates in a dose-dependent manner and that Cry5B binding to glycolipids was inhibited by the addition of LEC-8. LEC-8 is usually expressed strongly in the pharyngeal-intestinal valve and intestinal-rectal valve and is expressed weakly in intestine. However, when C. elegans were fed Escherichia coli expressing Cry5B, intestinal LEC-8::EGFP protein levels increased markedly. In contrast, LEC-8::EGFP expression triggered by Cry5B was reduced in toxin-resistant C. elegans mutants, which had mutations in genes involved in biosynthesis of glycolipids. Moreover, the LEC-8-deficient mutant was more susceptible to Cry5B than wild-type worms. These results suggest that the glycolipid-binding lectin LEC-8 contributes to host defense against bacterial infection by competitive binding to target glycolipid molecules. PMID:19635802

  4. A Caenorhabditis elegans glycolipid-binding galectin functions in host defense against bacterial infection.

    Science.gov (United States)

    Ideo, Hiroko; Fukushima, Keiko; Gengyo-Ando, Keiko; Mitani, Shohei; Dejima, Katsufumi; Nomura, Kazuya; Yamashita, Katsuko

    2009-09-25

    Galectins are a family of beta-galactoside-binding proteins that are widely found among animal species and that regulate diverse biological phenomena. To study the biological function of glycolipid-binding galectins, we purified recombinant Caenorhabditis elegans galectins (LEC-1-11) and studied their binding to C. elegans glycolipids. We found that LEC-8 binds to glycolipids in C. elegans through carbohydrate recognition. It has been reported that Cry5B-producing Bacillus thuringiensis strains can infect C. elegans and that the C. elegans Cry5B receptor molecules are glycolipids. We found that Cry5B and LEC-8 bound to C. elegans glycolipid-coated plates in a dose-dependent manner and that Cry5B binding to glycolipids was inhibited by the addition of LEC-8. LEC-8 is usually expressed strongly in the pharyngeal-intestinal valve and intestinal-rectal valve and is expressed weakly in intestine. However, when C. elegans were fed Escherichia coli expressing Cry5B, intestinal LEC-8::EGFP protein levels increased markedly. In contrast, LEC-8::EGFP expression triggered by Cry5B was reduced in toxin-resistant C. elegans mutants, which had mutations in genes involved in biosynthesis of glycolipids. Moreover, the LEC-8-deficient mutant was more susceptible to Cry5B than wild-type worms. These results suggest that the glycolipid-binding lectin LEC-8 contributes to host defense against bacterial infection by competitive binding to target glycolipid molecules.

  5. Mode of bacterial pathogenesis determines phenotype in elt-2 and elt-7 RNAi Caenorhabditis elegans.

    Science.gov (United States)

    Elliott, Samantha L; Sturgeon, Craig R; Travers, Deborah M; Montgomery, Madeline C

    2011-05-01

    Caenorhabditis elegans has become a useful model for studying innate immunity. ELT-2, which is homologous to human GATA-4, -5 and -6, is considered the primary GATA transcription factor controlling intestinal immunity in C. elegans. In this study, we characterize the timeline of intestinal distension in nematodes where ELT-2 and another intestinal GATA transcription factor, ELT-7, are abrogated by RNAi using two different models: colonization and toxin-based infections by Pseudomonas aeruginosa. We show that both ELT-2 and ELT-7 are important for survival of C. elegans exposed to P. aeruginosa. Intestinal distension is accelerated in elt-2 RNAi nematodes, and is observed in colonization but not toxin-based Pseudomonas infection. Upon onset of intestinal distension, nematodes die within 24 h, regardless of experimental treatment. These data provide new insight into the role of ELT-2 and ELT-7 in protecting C. elegans against P. aeruginosa infection. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Brief Communication: SIR-2.1-dependent lifespan extension of Caenorhabditis elegans by oxyresveratrol and resveratrol.

    Science.gov (United States)

    Lee, Jiyun; Kwon, Gayeung; Park, Jieun; Kim, Jeong-Keun; Lim, Young-Hee

    2016-10-01

    Resveratrol (RES) has been studied for its effects on the lifespan extension of Caenorhabditis elegans, but controversy still remains on its mechanism related with SIR-2. In this study, longevity assay was performed to confirm SIR-2-dependent lifespan extension of C. elgeans with RES and oxyresveratrol (OXY), an isomer of hydroxylated RES using loss-of-function mutants of C. elegans including sir-2.1 mutant. The results showed that OXY and RES significantly (P elegans compared with the control. OXY and RES also significantly (P elegans by overexpression of SIR-2.1, which is related to lifespan extension through calorie restriction and the AMP-activated protein kinase (AMPK) pathway, although this process is independent of the FOXO/DAF-16 pathway. © 2016 by the Society for Experimental Biology and Medicine.

  7. The neural circuits and sensory channels mediating harsh touch sensation in Caenorhabditis elegans.

    Science.gov (United States)

    Li, Wei; Kang, Lijun; Piggott, Beverly J; Feng, Zhaoyang; Xu, X Z Shawn

    2011-01-01

    Most animals can distinguish two distinct types of touch stimuli: gentle (innocuous) and harsh (noxious/painful) touch, however, the underlying mechanisms are not well understood. Caenorhabditis elegans is a useful model for the study of gentle touch sensation. However, little is known about harsh touch sensation in this organism. Here we characterize harsh touch sensation in C. elegans. We show that C. elegans exhibits differential behavioural responses to harsh touch and gentle touch. Laser ablations identify distinct sets of sensory neurons and interneurons required for harsh touch sensation at different body segments. Optogenetic stimulation of the circuitry can drive behaviour. Patch-clamp recordings reveal that TRP family and amiloride-sensitive Na(+) channels mediate touch-evoked currents in different sensory neurons. Our work identifies the neural circuits and characterizes the sensory channels mediating harsh touch sensation in C. elegans, establishing it as a genetic model for studying this sensory modality.

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

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    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

  9. 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...

  10. An atlas of Caenorhabditis elegans chemoreceptor expression

    Science.gov (United States)

    Vidal, Berta; Aghayeva, Ulkar; Sun, Haosheng; Wang, Chen; Glenwinkel, Lori; Bayer, Emily A.

    2018-01-01

    One goal of modern day neuroscience is the establishment of molecular maps that assign unique features to individual neuron types. Such maps provide important starting points for neuron classification, for functional analysis, and for developmental studies aimed at defining the molecular mechanisms of neuron identity acquisition and neuron identity diversification. In this resource paper, we describe a nervous system-wide map of the potential expression sites of 244 members of the largest gene family in the C. elegans genome, rhodopsin-like (class A) G-protein-coupled receptor (GPCR) chemoreceptors, using classic gfp reporter gene technology. We cover representatives of all sequence families of chemoreceptor GPCRs, some of which were previously entirely uncharacterized. Most reporters are expressed in a very restricted number of cells, often just in single cells. We assign GPCR reporter expression to all but two of the 37 sensory neuron classes of the sex-shared, core nervous system. Some sensory neurons express a very small number of receptors, while others, particularly nociceptive neurons, coexpress several dozen GPCR reporter genes. GPCR reporters are also expressed in a wide range of inter- and motorneurons, as well as non-neuronal cells, suggesting that GPCRs may constitute receptors not just for environmental signals, but also for internal cues. We observe only one notable, frequent association of coexpression patterns, namely in one nociceptive amphid (ASH) and two nociceptive phasmid sensory neurons (PHA, PHB). We identified GPCRs with sexually dimorphic expression and several GPCR reporters that are expressed in a left/right asymmetric manner. We identified a substantial degree of GPCR expression plasticity; particularly in the context of the environmentally-induced dauer diapause stage when one third of all tested GPCRs alter the cellular specificity of their expression within and outside the nervous system. Intriguingly, in a number of cases, the dauer

  11. Evolution of outcrossing in experimental populations of Caenorhabditis elegans.

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    Henrique Teotonio

    Full Text Available Caenorhabditis elegans can reproduce exclusively by self-fertilization. Yet, males can be maintained in laboratory populations, a phenomenon that continues to puzzle biologists. In this study we evaluated the role of males in facilitating adaptation to novel environments. For this, we contrasted the evolution of a fitness component exclusive to outcrossing in experimental populations of different mating systems. We introgressed a modifier of outcrossing into a hybrid population derived from several wild isolates to transform the wild-type androdioecious mating system into a dioecious mating system. By genotyping 375 single-nucleotide polymorphisms we show that the two populations had similar standing genetic diversity available for adaptation, despite the occurrence of selection during their derivation. We then performed replicated experimental evolution under the two mating systems from starting conditions of either high or low levels of diversity, under defined environmental conditions of discrete non-overlapping generations, constant density at high population sizes (N = 10(4, no obvious spatial structure and abundant food resources. During 100 generations measurements of sex ratios and male competitive performance showed: 1 adaptation to the novel environment; 2 directional selection on male frequency under androdioecy; 3 optimal outcrossing rates of 0.5 under androdioecy; 4 the existence of initial inbreeding depression; and finally 5 that the strength of directional selection on male competitive performance does not depend on male frequencies. Taken together, these results suggest that androdioecious males are maintained at intermediate frequencies because outcrossing is adaptive.

  12. AMPK blocks starvation-inducible transgenerational defects in Caenorhabditis elegans

    Science.gov (United States)

    Demoinet, Emilie; Li, Shaolin; Roy, Richard

    2017-01-01

    Life history events, such as traumatic stress, illness, or starvation, can influence us through molecular changes that are recorded in a pattern of characteristic chromatin modifications. These modifications are often associated with adaptive adjustments in gene expression that can persist throughout the lifetime of the organism, or even span multiple generations. Although these adaptations may confer some selective advantage, if they are not appropriately regulated they can also be maladaptive in a context-dependent manner. We show here that during periods of acute starvation in Caenorhabditis elegans larvae, the master metabolic regulator AMP-activated protein kinase (AMPK) plays a critical role in blocking modifications to the chromatin landscape. This ensures that gene expression remains inactive in the germ-line precursors during adverse conditions. In its absence, critical chromatin modifications occur in the primordial germ cells (PGCs) of emergent starved L1 larvae that correlate with compromised reproductive fitness of the generation that experienced the stress, but also in the subsequent generations that never experienced the initial event. Our findings suggest that AMPK regulates the activity of the chromatin modifying COMPASS complex (complex proteins associated with Set1) to ensure that chromatin marks are not established until nutrient/energy contingencies are satisfied. Our study provides molecular insight that links metabolic adaptation to transgenerational epigenetic modification in response to acute periods of starvation. PMID:28289190

  13. Arbutin increases Caenorhabditis elegans longevity and stress resistance

    Directory of Open Access Journals (Sweden)

    Lin Zhou

    2017-12-01

    Full Text Available Arbutin (p-hydroxyphenyl-β-D-glucopyranoside, a well-known tyrosinase inhibitor, has been widely used as a cosmetic whitening agent. Although its natural role is to scavenge free radicals within cells, it has also exhibited useful activities for the treatment of diuresis, bacterial infections and cancer, as well as anti-inflammatory and anti-tussive activities. Because function of free radical scavenging is also related to antioxidant and the effects of arbutin on longevity and stress resistance in animals have not yet been confirmed, here the effects of arbutin on Caenorhabditis elegans were investigated. The results demonstrated that optimal concentrations of arbutin could extend lifespan and enhance resistance to oxidative stress. The underlying molecular mechanism for these effects involves decreased levels of reactive oxygen species (ROS, improvement of daf-16 nuclear localization, and up-regulated expression of daf-16 and its downstream targets, including sod-3 and hsp16.2. In this work the roles of arbutin in lifespan and health are studied and the results support that arbutin is an antioxidant for maintaining overall health.

  14. Evolutionarily conserved TRH neuropeptide pathway regulates growth in Caenorhabditis elegans.

    Science.gov (United States)

    Van Sinay, Elien; Mirabeau, Olivier; Depuydt, Geert; Van Hiel, Matthias Boris; Peymen, Katleen; Watteyne, Jan; Zels, Sven; Schoofs, Liliane; Beets, Isabel

    2017-05-16

    In vertebrates thyrotropin-releasing hormone (TRH) is a highly conserved neuropeptide that exerts the hormonal control of thyroid-stimulating hormone (TSH) levels as well as neuromodulatory functions. However, a functional equivalent in protostomian animals remains unknown, although TRH receptors are conserved in proto- and deuterostomians. Here we identify a TRH-like neuropeptide precursor in Caenorhabditis elegans that belongs to a bilaterian family of TRH precursors. Using CRISPR/Cas9 and RNAi reverse genetics, we show that TRH-like neuropeptides, through the activation of their receptor TRHR-1, promote growth in Celegans TRH-like peptides from pharyngeal motor neurons are required for normal body size, and knockdown of their receptor in pharyngeal muscle cells reduces growth. Mutants deficient for TRH signaling have no defects in pharyngeal pumping or isthmus peristalsis rates, but their growth defect depends on the bacterial diet. In addition to the decrease in growth, trh-1 mutants have a reduced number of offspring. Our study suggests that TRH is an evolutionarily ancient neuropeptide, having its origin before the divergence of protostomes and deuterostomes, and may ancestrally have been involved in the control of postembryonic growth and reproduction.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Gene pathways that delay Caenorhabditis elegans reproductive senescence.

    Directory of Open Access Journals (Sweden)

    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.

  17. A Disease Model of Muscle Necrosis Caused by Aeromonas dhakensis Infection in Caenorhabditis elegans.

    Science.gov (United States)

    Chen, Po-Lin; Chen, Yi-Wei; Ou, Chun-Chun; Lee, Tzer-Min; Wu, Chi-Jung; Ko, Wen-Chien; Chen, Chang-Shi

    2016-01-01

    A variety of bacterial infections cause muscle necrosis in humans. Caenorhabditis elegans has epidermis and bands of muscle that resemble soft-tissue structures in mammals and humans. Here, we developed a muscle necrosis model caused by Aeromonas dhakensis infection in C. elegans. Our data showed that A. dhakensis infected and killed C. elegans rapidly. Characteristic muscle damage in C. elegans induced by A. dhakensis was demonstrated in vivo. Relative expression levels of host necrosis-associated genes, asp-3, asp-4, and crt-1 increased significantly after A. dhakensis infection. The RNAi sensitive NL2099 rrf-3 (pk1426) worms with knockdown of necrosis genes of crt-1 and asp-4 by RNAi showed prolonged survival after A. dhakensis infection. Specifically knockdown of crt-1 and asp-4 by RNAi in WM118 worms, which restricted RNAi only to the muscle cells, conferred significant resistance to A. dhakensis infection. In contrast, the severity of muscle damage and toxicity produced by the A. dhakensis hemolysin-deletion mutant is attenuated. In another example, shiga-like toxin-producing enterohemorrhagic E. coli (EHEC) known to elicit toxicity to C. elegans with concomitant enteropathogenicty, did not cause muscle necrosis as A. dhakensis did. Taken together, these results show that Aeromonas infection induces muscle necrosis and rapid death of infected C. elegans, which are similar to muscle necrosis in humans, and then validate the value of the C. elegans model with A. dhakensis infection in studying Aeromonas pathogenicity.

  18. The Energy Metabolism in Caenorhabditis elegans under The Extremely Low-Frequency Electromagnetic Field Exposure

    OpenAIRE

    Shi, Zhenhua; Yu, Hui; Sun, Yongyan; Yang, Chuanjun; Lian, Huiyong; Cai, Peng

    2015-01-01

    A literal mountain of documentation generated in the past five decades showing unmistakable health hazards associated with extremely low-frequency electromagnetic fields (ELF-EMFs) exposure. However, the relation between energy mechanism and ELF-EMF exposure is poorly understood. In this study, Caenorhabditis elegans was exposed to 50?Hz ELF-EMF at intensities of 0.5, 1, 2, and 3?mT, respectively. Their metabolite variations were analyzed by GC-TOF/MS-based metabolomics. Although minimal meta...

  19. 5'-AMP-Activated Protein Kinase Signaling in Caenorhabditis elegans.

    Science.gov (United States)

    Ahmadi, Moloud; Roy, Richard

    AMP-activated protein kinase (AMPK) is one of the central regulators of cellular and organismal metabolism in eukaryotes. Once activated by decreased energy levels, it induces ATP production by promoting catabolic pathways while conserving ATP by inhibiting anabolic pathways. AMPK plays a crucial role in various aspects of cellular function such as regulating growth, reprogramming metabolism, autophagy, and cell polarity. In this chapter, we focus on how recent breakthroughs made using the model organism Caenorhabditis elegans have contributed to our understanding of AMPK function and how it can be utilized in the future to elucidate hitherto unknown aspects of AMPK signaling.

  20. Mortality Rates in a Genetically Heterogeneous Population of Caenorhabditis elegans

    Science.gov (United States)

    Brooks, Anne; Lithgow, Gordon J.; Johnson, Thomas E.

    1994-02-01

    Age-specific mortality rates in isogenic populations of the nematode Caenorhabditis elegans increase exponentially throughout life. In genetically heterogeneous populations, age-specific mortality increases exponentially until about 17 days and then remains constant until the last death occurs at about 60 days. This period of constant age-specific mortality results from genetic heterogeneity. Subpopulations differ in mean life-span, but they all exhibit near exponential, albeit different, rates of increase in age-specific mortality. Thus, much of the observed heterogeneity in mortality rates later in life could result from genetic heterogeneity and not from an inherent effect of aging.

  1. Pathogenic bacteria induce aversive olfactory learning in Caenorhabditis elegans.

    Science.gov (United States)

    Zhang, Yun; Lu, Hang; Bargmann, Cornelia I

    2005-11-10

    Food can be hazardous, either through toxicity or through bacterial infections that follow the ingestion of a tainted food source. Because learning about food quality enhances survival, one of the most robust forms of olfactory learning is conditioned avoidance of tastes associated with visceral malaise. The nematode Caenorhabditis elegans feeds on bacteria but is susceptible to infection by pathogenic bacteria in its natural environment. Here we show that C. elegans modifies its olfactory preferences after exposure to pathogenic bacteria, avoiding odours from the pathogen and increasing its attraction to odours from familiar nonpathogenic bacteria. Particular bacteria elicit specific changes in olfactory preferences that are suggestive of associative learning. Exposure to pathogenic bacteria increases serotonin in ADF chemosensory neurons by transcriptional and post-transcriptional mechanisms. Serotonin functions through MOD-1, a serotonin-gated chloride channel expressed in sensory interneurons, to promote aversive learning. An increase in serotonin may represent the negative reinforcing stimulus in pathogenic infection.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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...... relatively easily be performed in a genome-wide fashion. In this chapter we give a protocol for using genome-wide RNAi screening to identify genes involved with the response to genotoxic stress...

  4. 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.

  5. 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

  6. 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...

  7. l-Arginine Enhances Resistance against Oxidative Stress and Heat Stress in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    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.

  8. Most Caenorhabditis elegans microRNAs are individually not essential for development or viability.

    Directory of Open Access Journals (Sweden)

    Eric A Miska

    2007-12-01

    Full Text Available MicroRNAs (miRNAs, a large class of short noncoding RNAs found in many plants and animals, often act to post-transcriptionally inhibit gene expression. We report the generation of deletion mutations in 87 miRNA genes in Caenorhabditis elegans, expanding the number of mutated miRNA genes to 95, or 83% of known C. elegans miRNAs. We find that the majority of miRNAs are not essential for the viability or development of C. elegans, and mutations in most miRNA genes do not result in grossly abnormal phenotypes. These observations are consistent with the hypothesis that there is significant functional redundancy among miRNAs or among gene pathways regulated by miRNAs. This study represents the first comprehensive genetic analysis of miRNA function in any organism and provides a unique, permanent resource for the systematic study of miRNAs.

  9. Evaluation of role of oxidative stress on aging in Caenorhabditis elegans: a brief review.

    Science.gov (United States)

    Prasad, Kedar N; Bondy, Stephen C

    2013-12-01

    Recently the relationship between oxidative stress and aging has been brought into question. It has been suggested that while oxidative events may play a role in the progression of age-related pathologies, it is not relevant to aging processes not involving specific diseases associated with senescence. The evidence in support of this concept is largely based on studies with the roundworm, Caenorhabditis elegans (C. elegans) that has been extensively used as a model system to study aging. This commentary evaluates data derived from C. elegans and documents that the preponderance of evidence from this species supports the role of pro-oxidant events as being a significant contributor to normal aging. Possible reasons for some anomalous findings conflicting with this concept, are discussed.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria

    Science.gov (United States)

    Portal-Celhay, Cynthia; Nehrke, Keith; Blaser, Martin J.

    2013-01-01

    Horizontal gene transfer (HGT) between bacteria occurs in the intestinal tract of their animal hosts and facilitates both virulence and antibiotic resistance. A model in which both the pathogen and the host are genetically tractable facilitates developing insight into mechanistic processes enabling or restricting the transfer of antibiotic resistance genes. Here we develop an in vivo experimental system to study HGT in bacteria using Caenorhabditis elegans as a model host. Using a thermosensitive conjugative system, we provide evidence that conjugation between two Escherichia coli strains can take place in the intestinal lumen of N2 wild-type worms at a rate of 10−3 and 10−2 per donor. We also show that C. elegans age and genotype are important determinants of the frequency of conjugation. Whereas ∼1 transconjugant for every 100 donor cells could be recovered from the intestine of N2 C. elegans, for the age-1 and tol-1 mutants, the detected rate of transconjugation (10−3 and 10−4 per donor cell, respectively) was significantly lower. This work demonstrates that increased recombination among lumenal microbial populations is a phenotype associated with host aging, and the model provides a framework to study the dynamics of bacterial horizontal gene transfer within the intestinal environment.—Portal-Celhay, C., Nehrke, K., Blaser, M. J. Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria. PMID:23085995

  12. Untangling Longevity, Dauer, and Healthspan in Caenorhabditis elegans Insulin/IGF-1-Signalling.

    Science.gov (United States)

    Ewald, Collin Yvès; Castillo-Quan, Jorge Iván; Blackwell, T Keith

    2017-09-22

    The groundbreaking discovery that lower levels of insulin/IGF-1 signaling (IIS) can induce lifespan extension was reported 24 years ago in the nematode Caenorhabditis elegans. In this organism, mutations in the insulin/IGF-1 receptor gene daf-2 or other genes in this pathway can double lifespan. Subsequent work has revealed that reduced IIS (rIIS) extends lifespan across diverse species, possibly including humans. In C. elegans, IIS also regulates development into the diapause state known as dauer, a quiescent larval form that enables C. elegans to endure harsh environments through morphological adaptation, improved cellular repair, and slowed metabolism. Considerable progress has been made uncovering mechanisms that are affected by C. elegans rIIS. However, from the beginning it has remained unclear to what extent rIIS extends C. elegans lifespan by mobilizing dauer-associated mechanisms in adults. As we discuss, recent work has shed light on this question by determining that rIIS can extend C. elegans lifespan comparably through downstream processes that are either dauer-related or -independent. Importantly, these two lifespan extension programs can be distinguished genetically. It will now be critical to tease apart these programs, because each may involve different longevity-promoting mechanisms that may be relevant to higher organisms. A recent analysis of organismal "healthspan" has questioned the value of C. elegans rIIS as a paradigm for understanding healthy aging, as opposed to simply extending life. We discuss other work that argues strongly that C. elegans rIIS is indeed an invaluable model and consider the likely possibility that dauer-related processes affect parameters associated with health under rIIS conditions. Together, these studies indicate that C. elegans and analyses of rIIS in this organism will continue to provide unexpected and exciting results, and new paradigms that will be valuable for understanding healthy aging in humans. © 2017 S

  13. 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

  14. The rise and fall of basal bodies in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Nechipurenko, Inna V; Sengupta, Piali

    2017-01-01

    The free-living nematode, Caenorhabditis elegans, is a widely used genetic model organism for investigations into centriole and cilia biology. Only sensory neurons are ciliated in C. elegans; morphologically diverse cilia in these neurons are nucleated by basal bodies located at the dendritic endings. C. elegans centrioles comprise a central tube with a symmetric array of nine singlet microtubules. These singlet microtubules remodel in a subset of sensory neurons to form the doublet microtubules of the basal bodies. Following initiation of ciliogenesis, the central tube, but not the outer centriole wall, of the basal body degenerates. Recent ultrastructural characterization of basal body architecture and remodeling have laid the foundation for future studies into mechanisms underlying different aspects of basal body genesis, remodeling, and intracellular positioning.

  15. Combination therapy with thioridazine and dicloxacillin combats methicillin-resistant Staphylococcus aureus infection in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Poulsen, Marianne Østergaard; Schøler, Lone; Nielsen, Anette

    2014-01-01

    , but experiments in simple animal models have not been performed. In the present study, we introduced Caenorhabditis elegans infected by S. aureus as an in vivo model to test the effect of TZ as a helper drug in combination with DCX. Because TZ is an anthelmintic, initial experiments were carried out to define...... the thresholds of toxicity, determined by larval development, and induction of stress-response markers. No measurable effects were seen at concentrations of less than 64 mg TZ l(-1). Seven different MRSA strains were tested for pathogenicity against C. elegans, and the most virulent strain (ATCC 33591......) was selected for further analyses. In a final experiment, full-grown C. elegans were exposed to the test strain for 3 days and subsequently treated with 8 mg DCX l(-1) and 8 mg TZ l(-1) for 2 days. This resulted in a 14-fold reduction in the intestinal MRSA load as compared with untreated controls. Each drug...

  16. 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.

  17. 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.

  18. Radiation biology of Caenorhabditis elegans: germ cell response, aging and behavior.

    Science.gov (United States)

    Sakashita, Tetsuya; Takanami, Takako; Yanase, Sumino; Hamada, Nobuyuki; Suzuki, Michiyo; Kimura, Takafumi; Kobayashi, Yasuhiko; Ishii, Naoaki; Higashitani, Atsushi

    2010-01-01

    The study of radiation effect in Caenorhabditis (C.) elegans has been carried out over three decades and now allow for understanding at the molecular, cellular and individual levels. This review describes the current knowledge of the biological effects of ionizing irradiation with a scope of the germ line, aging and behavior. In germ cells, ionizing radiation induces apoptosis, cell cycle arrest and DNA repair. Lots of molecules involved in these responses and functions have been identified in C. elegans, which are highly conserved throughout eukaryotes. Radiosensitivity and the effect of heavy-ion microbeam irradiation on germ cells with relationship between initiation of meiotic recombination and DNA lesions are discussed. In addition to DNA damage, ionizing radiation produces free radicals, and the free radical theory is the most popular aging theory. A first signal transduction pathway of aging has been discovered in C. elegans, and radiation-induced metabolic oxidative stress is recently noted for an inducible factor of hormetic response and genetic instability. The hormetic response in C. elegans exposed to oxidative stress is discussed with genetic pathways of aging. Moreover, C. elegans is well known as a model organism for behavior. The recent work reported the radiation effects via specific neurons on learning behavior, and radiation and hydrogen peroxide affect the locomotory rate similarly. These findings are discussed in relation to the evidence obtained with other organisms. Altogether, C. elegans may be a good "in vivo" model system in the field of radiation biology.

  19. Giardia duodenalis-induced alterations of commensal bacteria kill Caenorhabditis elegans: a new model to study microbial-microbial interactions in the gut

    Science.gov (United States)

    Gerbaba, Teklu K.; Gupta, Pratyush; Rioux, Kevin; Hansen, Dave

    2015-01-01

    Giardia duodenalis is the most common cause of parasitic diarrhea worldwide and a well-established risk factor for postinfectious irritable bowel syndrome. We hypothesized that Giardia-induced disruptions in host-microbiota interactions may play a role in the pathogenesis of giardiasis and in postgiardiasis disease. Functional changes induced by Giardia in commensal bacteria and the resulting effects on Caenorhabditis elegans were determined. Although Giardia or bacteria alone did not affect worm viability, combining commensal Escherichia coli bacteria with Giardia became lethal to C. elegans. Giardia also induced killing of C. elegans with attenuated Citrobacter rodentium espF and map mutant strains, human microbiota from a healthy donor, and microbiota from inflamed colonic sites of ulcerative colitis patient. In contrast, combinations of Giardia with microbiota from noninflamed sites of the same patient allowed for worm survival. The synergistic lethal effects of Giardia and E. coli required the presence of live bacteria and were associated with the facilitation of bacterial colonization in the C. elegans intestine. Exposure to C. elegans and/or Giardia altered the expression of 172 genes in E. coli. The genes affected by Giardia included hydrogen sulfide biosynthesis (HSB) genes, and deletion of a positive regulator of HSB genes, cysB, was sufficient to kill C. elegans even in the absence of Giardia. Our findings indicate that Giardia induces functional changes in commensal bacteria, possibly making them opportunistic pathogens, and alters host-microbe homeostatic interactions. This report describes the use of a novel in vivo model to assess the toxicity of human microbiota. PMID:25573177

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

    Directory of Open Access Journals (Sweden)

    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

  1. Germline expression influences operon organization in the Caenorhabditis elegans genome.

    Science.gov (United States)

    Reinke, Valerie; Cutter, Asher D

    2009-04-01

    Operons are found across multiple kingdoms and phyla, from prokaryotes to chordates. In the nematode Caenorhabditis elegans, the genome contains >1000 operons that compose approximately 15% of the protein-coding genes. However, determination of the force(s) promoting the origin and maintenance of operons in C. elegans has proved elusive. Compared to bacterial operons, genes within a C. elegans operon often show poor coexpression and only sometimes encode proteins with related functions. Using analysis of microarray and large-scale in situ hybridization data, we demonstrate that almost all operon-encoded genes are expressed in germline tissue. However, genes expressed during spermatogenesis are excluded from operons. Operons group together along chromosomes in local clusters that also contain monocistronic germline-expressed genes. Additionally, germline expression of genes in operons is largely independent of the molecular function of the encoded proteins. These analyses demonstrate that mechanisms governing germline gene expression influence operon origination and/or maintenance. Thus, gene expression in a specific tissue can have profound effects on the evolution of genome organization.

  2. Undulatory locomotion of Caenorhabditis elegans on wet surfaces.

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    Shen, X N; Sznitman, J; Krajacic, P; Lamitina, T; Arratia, P E

    2012-06-20

    The physical and biomechanical principles that govern undulatory movement on wet surfaces have important applications in physiology, physics, and engineering. The nematode Caenorhabditis elegans, with its highly stereotypical and functionally distinct sinusoidal locomotory gaits, is an excellent system in which to dissect these properties. Measurements of the main forces governing the C. elegans crawling gait on lubricated surfaces have been scarce, primarily due to difficulties in estimating the physical features at the nematode-gel interface. Using kinematic data and a hydrodynamic model based on lubrication theory, we calculate both the surface drag forces and the nematode's bending force while crawling on the surface of agar gels within a preexisting groove. We find that the normal and tangential surface drag coefficients during crawling are ∼222 and 22, respectively, and the drag coefficient ratio is ∼10. During crawling, the calculated internal bending force is time-periodic and spatially complex, exhibiting a phase lag with respect to the nematode's body bending curvature. This phase lag is largely due to viscous drag forces, which are higher during crawling as compared to swimming in an aqueous buffer solution. The spatial patterns of bending force generated during either swimming or crawling correlate well with previously described gait-specific features of calcium signals in muscle. Further, our analysis indicates that one may be able to control the motility gait of C. elegans by judiciously adjusting the magnitude of the surface drag coefficients. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Tomosyn inhibits synaptic vesicle priming in Caenorhabditis elegans.

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    Elena O Gracheva

    2006-07-01

    Full Text Available Caenorhabditis elegans TOM-1 is orthologous to vertebrate tomosyn, a cytosolic syntaxin-binding protein implicated in the modulation of both constitutive and regulated exocytosis. To investigate how TOM-1 regulates exocytosis of synaptic vesicles in vivo, we analyzed C. elegans tom-1 mutants. Our electrophysiological analysis indicates that evoked postsynaptic responses at tom-1 mutant synapses are prolonged leading to a two-fold increase in total charge transfer. The enhanced response in tom-1 mutants is not associated with any detectable changes in postsynaptic response kinetics, neuronal outgrowth, or synaptogenesis. However, at the ultrastructural level, we observe a concomitant increase in the number of plasma membrane-contacting vesicles in tom-1 mutant synapses, a phenotype reversed by neuronal expression of TOM-1. Priming defective unc-13 mutants show a dramatic reduction in plasma membrane-contacting vesicles, suggesting these vesicles largely represent the primed vesicle pool at the C. elegans neuromuscular junction. Consistent with this conclusion, hyperosmotic responses in tom-1 mutants are enhanced, indicating the primed vesicle pool is enhanced. Furthermore, the synaptic defects of unc-13 mutants are partially suppressed in tom-1 unc-13 double mutants. These data indicate that in the intact nervous system, TOM-1 negatively regulates synaptic vesicle priming.

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

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    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.

  5. Isotopic ratio outlier analysis global metabolomics of Caenorhabditis elegans.

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    Stupp, Gregory S; Clendinen, Chaevien S; Ajredini, Ramadan; Szewc, Mark A; Garrett, Timothy; Menger, Robert F; Yost, Richard A; Beecher, Chris; Edison, Arthur S

    2013-12-17

    We demonstrate the global metabolic analysis of Caenorhabditis elegans stress responses using a mass-spectrometry-based technique called isotopic ratio outlier analysis (IROA). In an IROA protocol, control and experimental samples are isotopically labeled with 95 and 5% (13)C, and the two sample populations are mixed together for uniform extraction, sample preparation, and LC-MS analysis. This labeling strategy provides several advantages over conventional approaches: (1) compounds arising from biosynthesis are easily distinguished from artifacts, (2) errors from sample extraction and preparation are minimized because the control and experiment are combined into a single sample, (3) measurement of both the molecular weight and the exact number of carbon atoms in each molecule provides extremely accurate molecular formulas, and (4) relative concentrations of all metabolites are easily determined. A heat-shock perturbation was conducted on C. elegans to demonstrate this approach. We identified many compounds that significantly changed upon heat shock, including several from the purine metabolism pathway. The metabolomic response information by IROA may be interpreted in the context of a wealth of genetic and proteomic information available for C. elegans . Furthermore, the IROA protocol can be applied to any organism that can be isotopically labeled, making it a powerful new tool in a global metabolomics pipeline.

  6. Effects of ginsenosides, the active ingredients of Panax ginseng, on development, growth, and life span of Caenorhabditis elegans

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    Ginsenosides, the active ingredients of Panax ginseng, are saponins derived from sterols. The free-living nematode Caenorhabditis elegans is a well-established model for biochemical and genetic studies in animals. Although cholesterol is an essential requirement for the growth and development of C. ...

  7. A Caenorhabditis elegans Host Model Correlates with Invasive Disease Caused by Staphylococcus aureus Recovered during an Outbreak in Neonatal Intensive Care

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    Kaiyu Wu

    2012-01-01

    Full Text Available BACKGROUND: Caenorhabditis elegans has previously been used as a host model to determine the virulence of clinical methicillin-resistant Staphylococcus aureus isolates. In the present study, methicillin-susceptible S aureus (MSSA strains associated with an outbreak in a neonatal intensive care unit (NICU were investigated using the C elegans model.

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

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    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.

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

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    Park, Sojin; Choi, Seoyun; Ahn, Byungchan

    2016-01-01

    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. PMID:26903030

  10. 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.

  11. A highly accurate inclusive cancer screening test using Caenorhabditis elegans scent detection.

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    Takaaki Hirotsu

    Full Text Available Early detection and treatment are of vital importance to the successful eradication of various cancers, and development of economical and non-invasive novel cancer screening systems is critical. Previous reports using canine scent detection demonstrated the existence of cancer-specific odours. However, it is difficult to introduce canine scent recognition into clinical practice because of the need to maintain accuracy. In this study, we developed a Nematode Scent Detection Test (NSDT using Caenorhabditis elegans to provide a novel highly accurate cancer detection system that is economical, painless, rapid and convenient. We demonstrated wild-type C. elegans displayed attractive chemotaxis towards human cancer cell secretions, cancer tissues and urine from cancer patients but avoided control urine; in parallel, the response of the olfactory neurons of C. elegans to the urine from cancer patients was significantly stronger than to control urine. In contrast, G protein α mutants and olfactory neurons-ablated animals were not attracted to cancer patient urine, suggesting that C. elegans senses odours in urine. We tested 242 samples to measure the performance of the NSDT, and found the sensitivity was 95.8%; this is markedly higher than that of other existing tumour markers. Furthermore, the specificity was 95.0%. Importantly, this test was able to diagnose various cancer types tested at the early stage (stage 0 or 1. To conclude, C. elegans scent-based analyses might provide a new strategy to detect and study disease-associated scents.

  12. Systems biology approach to late-onset Alzheimer's disease genome-wide association study identifies novel candidate genes validated using brain expression data and Caenorhabditis elegans experiments.

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    Mukherjee, Shubhabrata; Russell, Joshua C; Carr, Daniel T; Burgess, Jeremy D; Allen, Mariet; Serie, Daniel J; Boehme, Kevin L; Kauwe, John S K; Naj, Adam C; Fardo, David W; Dickson, Dennis W; Montine, Thomas J; Ertekin-Taner, Nilufer; Kaeberlein, Matt R; Crane, Paul K

    2017-10-01

    We sought to determine whether a systems biology approach may identify novel late-onset Alzheimer's disease (LOAD) loci. We performed gene-wide association analyses and integrated results with human protein-protein interaction data using network analyses. We performed functional validation on novel genes using a transgenic Caenorhabditis elegans Aβ proteotoxicity model and evaluated novel genes using brain expression data from people with LOAD and other neurodegenerative conditions. We identified 13 novel candidate LOAD genes outside chromosome 19. Of those, RNA interference knockdowns of the C. elegans orthologs of UBC, NDUFS3, EGR1, and ATP5H were associated with Aβ toxicity, and NDUFS3, SLC25A11, ATP5H, and APP were differentially expressed in the temporal cortex. Network analyses identified novel LOAD candidate genes. We demonstrated a functional role for four of these in a C. elegans model and found enrichment of differentially expressed genes in the temporal cortex. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  13. Potential Nematode Alarm Pheromone Induces Acute Avoidance in Caenorhabditis elegans.

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    Zhou, Ying; Loeza-Cabrera, Mario; Liu, Zheng; Aleman-Meza, Boanerges; Nguyen, Julie K; Jung, Sang-Kyu; Choi, Yuna; Shou, Qingyao; Butcher, Rebecca A; Zhong, Weiwei

    2017-07-01

    It is crucial for animal survival to detect dangers such as predators. A good indicator of dangers is injury of conspecifics. Here we show that fluids released from injured conspecifics invoke acute avoidance in both free-living and parasitic nematodes. Caenorhabditis elegans avoids extracts from closely related nematode species but not fruit fly larvae. The worm extracts have no impact on animal lifespan, suggesting that the worm extract may function as an alarm instead of inflicting physical harm. Avoidance of the worm extract requires the function of a cGMP signaling pathway that includes the cGMP-gated channel TAX-2/TAX-4 in the amphid sensory neurons ASI and ASK. Genetic evidence indicates that the avoidance behavior is modulated by the neurotransmitters GABA and serotonin, two common targets of anxiolytic drugs. Together, these data support a model that nematodes use a nematode-specific alarm pheromone to detect conspecific injury. Copyright © 2017 by the Genetics Society of America.

  14. Effects of Microcystin-LR Exposure on Spermiogenesis in Nematode Caenorhabditis elegans.

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    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.

  15. Glial development and function in the nervous system of Caenorhabditis elegans.

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    Shaham, Shai

    2015-01-08

    The nematode, Caenorhabditis elegans, has served as a fruitful setting for understanding conserved biological processes. The past decade has seen the rise of this model organism as an important tool for uncovering the mysteries of the glial cell, which partners with neurons to generate a functioning nervous system in all animals. C. elegans affords unparalleled single-cell resolution in vivo in examining glia-neuron interactions, and similarities between C. elegans and vertebrate glia suggest that lessons learned from this nematode are likely to have general implications. Here, I summarize what has been gleaned over the past decade since C. elegans glia research became a concerted area of focus. Studies have revealed that glia are essential elements of a functioning C. elegans nervous system and play key roles in its development. Importantly, glial influence on neuronal function appears to be dynamic. Key questions for the field to address in the near- and long-term have emerged, and these are discussed within. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

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

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    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

  17. Joint toxic effects on Caenorhabditis elegans

    NARCIS (Netherlands)

    Jonker, M.J.

    2003-01-01

    In polluted areas organisms are generally exposed to mixtures of toxic chemicals rather than a single toxicant only. Since the number of mixture toxicity studies with regard to soil systems is limited, the research in this thesis was focused on investigating ecotoxicological consequences of combined

  18. FMRFamide related peptide ligands activate the Caenorhabditis elegans orphan GPCR Y59H11AL.1

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    G-protein coupled receptors (GPCRs) are ancient molecules that sense environmental and physiological signals. Currently, the majority of the predicted Caenorhabditis elegans GPCRs are orphan. Here, we describe the characterization of such an orphan C. elegans GPCR, which is categorized in the tachyk...

  19. 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.

  20. 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...

  1. 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…

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

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    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...

  3. Appetitive Olfactory Learning and Long-Term Associative Memory in Caenorhabditis elegans

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    Ichiro N. Maruyama

    2017-05-01

    Full Text Available Because of the relative simplicity of its nervous system, Caenorhabditis elegans is a useful model organism to study learning and memory at cellular and molecular levels. For appetitive conditioning in C. elegans, food has exclusively been used as an unconditioned stimulus (US. It may be difficult to analyze neuronal circuits for associative memory since food is a multimodal combination of olfactory, gustatory, and mechanical stimuli. Here, we report classical appetitive conditioning and associative memory in C. elegans, using 1-nonanol as a conditioned stimulus (CS, and potassium chloride (KCl as a US. Before conditioning, C. elegans innately avoided 1-nonanol, an aversive olfactory stimulus, and was attracted by KCl, an appetitive gustatory stimulus, on assay agar plates. Both massed training without an intertrial interval (ITI and spaced training with a 10-min ITI induced significant levels of memory of association regarding the two chemicals. Memory induced by massed training decayed within 6 h, while that induced by spaced training was retained for more than 6 h. Animals treated with inhibitors of transcription or translation formed the memory induced by spaced training less efficiently than untreated animals, whereas the memory induced by massed training was not significantly affected by such treatments. By definition, therefore, memories induced by massed training and spaced training are classified as short-term memory (STM and long-term memory (LTM, respectively. When animals conditioned by spaced training were exposed to 1-nonanol alone, their learning index was lower than that of untreated animals, suggesting that extinction learning occurs in C. elegans. In support of these results, C. elegans mutants defective in nmr-1, encoding an NMDA receptor subunit, formed both STM and LTM less efficiently than wild-type animals, while mutations in crh-1, encoding a ubiquitous transcription factor CREB required for memory consolidation, affected

  4. Fluorodeoxyuridine improves Caenorhabditis elegans proteostasis independent of reproduction onset.

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    Naama Feldman

    Full Text Available Protein homeostasis (proteostasis networks are dynamic throughout the lifespan of an organism. During Caenorhabditis elegans adulthood, the maintenance of metastable proteins and the activation of stress responses are inversely associated with germline stem cell proliferation. Here, we employed the thymidylate synthase inhibitor 5-fluoro-2'-deoxyuridine (FUdR to chemically inhibit reproduction, thus allowing for examination of the interplay between reproduction and somatic proteostasis. We found that treatment with FUdR modulates proteostasis decline both before and after reproduction onset, such that effective induction of the heat shock response was maintained during adulthood and that metastable temperature-sensitive mutant phenotypes were rescued under restrictive conditions. However, FUdR treatment also improved the folding capacity of germline- and gonadogenesis-defective mutants, suggesting that proteostasis modulation by FUdR is independent of germline stem cell proliferation or inhibition of reproduction. Our data, therefore, indicate that FUdR converges on alternative regulatory signals that modulate C. elegans proteostasis capacity during development and adulthood.

  5. Spatiotemporal regulation of autophagy during Caenorhabditis elegans aging

    Science.gov (United States)

    Chang, Jessica T; Kumsta, Caroline; Hellman, Andrew B; Adams, Linnea M; Hansen, Malene

    2017-01-01

    Autophagy has been linked to longevity in many species, but the underlying mechanisms are unclear. Using a GFP-tagged and a new tandem-tagged Atg8/LGG-1 reporter, we quantified autophagic vesicles and performed autophagic flux assays in multiple tissues of wild-type Caenorhabditis elegans and long-lived daf-2/insulin/IGF-1 and glp-1/Notch mutants throughout adulthood. Our data are consistent with an age-related decline in autophagic activity in the intestine, body-wall muscle, pharynx, and neurons of wild-type animals. In contrast, daf-2 and glp-1 mutants displayed unique age- and tissue-specific changes in autophagic activity, indicating that the two longevity paradigms have distinct effects on autophagy during aging. Although autophagy appeared active in the intestine of both long-lived mutants, inhibition of intestinal autophagy significantly abrogated lifespan extension only in glp-1 mutants. Collectively, our data suggest that autophagic activity normally decreases with age in C. elegans, whereas daf-2 and glp-1 long-lived mutants regulate autophagy in distinct spatiotemporal-specific manners to extend lifespan. DOI: http://dx.doi.org/10.7554/eLife.18459.001 PMID:28675140

  6. Farming and public goods production in Caenorhabditis elegans populations.

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    Thutupalli, Shashi; Uppaluri, Sravanti; Constable, George W A; Levin, Simon A; Stone, Howard A; Tarnita, Corina E; Brangwynne, Clifford P

    2017-02-28

    The ecological and evolutionary dynamics of populations are shaped by the strategies they use to produce and use resources. However, our understanding of the interplay between the genetic, behavioral, and environmental factors driving these strategies is limited. Here, we report on a Caenorhabditis elegans-Escherichia coli (worm-bacteria) experimental system in which the worm-foraging behavior leads to a redistribution of the bacterial food source, resulting in a growth advantage for both organisms, similar to that achieved via farming. We show experimentally and theoretically that the increased resource growth represents a public good that can benefit all other consumers, regardless of whether or not they are producers. Mutant worms that cannot farm bacteria benefit from farming by other worms in direct proportion to the fraction of farmers in the worm population. The farming behavior can therefore be exploited if it is associated with either energetic or survival costs. However, when the individuals compete for resources with their own type, these costs can result in an increased population density. Altogether, our findings reveal a previously unrecognized mechanism of public good production resulting from the foraging behavior of C. elegans, which has important population-level consequences. This powerful system may provide broad insight into exploration-exploitation tradeoffs, the resultant ecoevolutionary dynamics, and the underlying genetic and neurobehavioral driving forces of multispecies interactions.

  7. Counting mutagenized genomes and optimizing genetic screens in Caenorhabditis elegans.

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    Shaham, Shai

    2007-11-07

    In genetic screens, the number of mutagenized gametes examined is an important parameter for evaluating screen progress, the number of genes of a given mutable phenotype, gene size, cost, and labor. Since genetic screens often entail examination of thousands or tens of thousands of animals, strategies for optimizing genetics screens are important for minimizing effort while maximizing the number of mutagenized gametes examined. To date, such strategies have not been described for genetic screens in the nematode Caenorhabditis elegans. Here we review general principles of genetic screens in C. elegans, and use a modified binomial strategy to obtain a general expression for the number of mutagenized gametes examined in a genetic screen. We use this expression to calculate optimal screening parameters for a large range of genetic screen types. In addition, we developed a simple online genetic-screen-optimization tool that can be used independently of this paper. Our results demonstrate that choosing the optimal F2-to-F1 screening ratio can significantly improve screen efficiency.

  8. Counting mutagenized genomes and optimizing genetic screens in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Shai Shaham

    Full Text Available In genetic screens, the number of mutagenized gametes examined is an important parameter for evaluating screen progress, the number of genes of a given mutable phenotype, gene size, cost, and labor. Since genetic screens often entail examination of thousands or tens of thousands of animals, strategies for optimizing genetics screens are important for minimizing effort while maximizing the number of mutagenized gametes examined. To date, such strategies have not been described for genetic screens in the nematode Caenorhabditis elegans. Here we review general principles of genetic screens in C. elegans, and use a modified binomial strategy to obtain a general expression for the number of mutagenized gametes examined in a genetic screen. We use this expression to calculate optimal screening parameters for a large range of genetic screen types. In addition, we developed a simple online genetic-screen-optimization tool that can be used independently of this paper. Our results demonstrate that choosing the optimal F2-to-F1 screening ratio can significantly improve screen efficiency.

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

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    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.

  10. A Genetic Analysis of the Caenorhabditis elegans Detoxification Response.

    Science.gov (United States)

    Fukushige, Tetsunari; Smith, Harold E; Miwa, Johji; Krause, Michael W; Hanover, John A

    2017-06-01

    Oxidative damage contributes to human diseases of aging including diabetes, cancer, and cardiovascular disorders. Reactive oxygen species resulting from xenobiotic and endogenous metabolites are sensed by a poorly understood process, triggering a cascade of regulatory factors and leading to the activation of the transcription factor Nrf2 (Nuclear factor-erythroid-related factor 2, SKN-1 in Caenorhabditis elegans). Nrf2/SKN-1 activation promotes the induction of the phase II detoxification system that serves to limit oxidative stress. We have extended a previous C. elegans genetic approach to explore the mechanisms by which a phase II enzyme is induced by endogenous and exogenous oxidants. The xrep (xenobiotics response pathway) mutants were isolated as defective in their ability to properly regulate the induction of a glutathione S-transferase (GST) reporter. The xrep-1 gene was previously identified as wdr-23, which encodes a C. elegans homolog of the mammalian β-propeller repeat-containing protein WDR-23 Here, we identify and confirm the mutations in xrep-2, xrep-3, and xrep-4 The xrep-2 gene is alh-6, an ortholog of a human gene mutated in familial hyperprolinemia. The xrep-3 mutation is a gain-of-function allele of skn-1 The xrep-4 gene is F46F11.6, which encodes a F-box-containing protein. We demonstrate that xrep-4 alters the stability of WDR-23 (xrep-1), a key regulator of SKN-1 (xrep-3). Epistatic relationships among the xrep mutants and their interacting partners allow us to propose an ordered genetic pathway by which endogenous and exogenous stressors induce the phase II detoxification response. Copyright © 2017 by the Genetics Society of America.

  11. Structural properties of the Caenorhabditis elegans neuronal network.

    Directory of Open Access Journals (Sweden)

    Lav R Varshney

    2011-02-01

    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.

  12. The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety

    DEFF Research Database (Denmark)

    Juozaityte, Vaida; Pladevall-Morera, David; Podolska, Agnieszka

    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 ......-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....

  13. Shifts in the Distribution of Mass Densities Is a Signature of Caloric Restriction in Caenorhabditis elegans

    OpenAIRE

    Alfonso Reina; Anand Bala Subramaniam; Anna Laromaine; Aravinthan D T Samuel; Whitesides, George M.

    2013-01-01

    Although the starvation response of the model multicellular organism Caenorhabditis elegans is a subject of much research, there is no convenient phenotypic readout of caloric restriction that can be applicable to large numbers of worms. This paper describes the distribution of mass densities of populations of C. elegans, from larval stages up to day one of adulthood, using isopycnic centrifugation, and finds that density is a convenient, if complex, phenotypic readout in C. elegans. The dens...

  14. Chlorophyll enhances oxidative stress tolerance in Caenorhabditis elegans and extends its lifespan

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    Erjia Wang

    2016-04-01

    Full Text Available 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.

  15. Combination therapy with thioridazine and dicloxacillin combats meticillin-resistant Staphylococcus aureus infection in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Poulsen, Marianne Ø; Schøler, Lone; Nielsen, Anette

    2014-01-01

    The shortage of drugs active against meticillin-resistant Staphylococcus aureus (MRSA) is a growing clinical problem. In vitro studies indicate that the phenothiazine thioridazine (TZ) might enhance the activity of the β-lactam antibiotic dicloxacillin (DCX) to a level where MRSA is killed......, but experiments in simple animal models have not been performed. In the present study, we introduced Caenorhabditis elegans infected by S. aureus as an in vivo model to test the effect of TZ as a helper drug in combination with DCX. Because TZ is an anthelmintic, initial experiments were carried out to define...... the thresholds of toxicity, determined by larval development, and induction of stress-response markers. No measurable effects were seen at concentrations of less than 64 mg TZ l(-1). Seven different MRSA strains were tested for pathogenicity against C. elegans, and the most virulent strain (ATCC 33591...

  16. 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.

  17. Caenorhabditis elegans, a model organism for kidney research: from cilia to mechanosensation and longevity.

    Science.gov (United States)

    Müller, Roman-Ulrich; Zank, Sibylle; Fabretti, Francesca; Benzing, Thomas

    2011-07-01

    The introduction of Caenorhabditis elegans by Sydney Brenner to study 'how genes might specify the complex structures found in higher organisms' revolutionized molecular and developmental biology and pioneered a new research area to study organ development and cellular differentiation with this model organism. Here, we review the role of the nematode in renal research and discuss future perspectives for its use in molecular nephrology. Although C. elegans does not possess an excretory system comparable with the mammalian kidney, various studies have demonstrated the conserved functional role of kidney disease genes in C. elegans. The finding that cystic kidney diseases can be considered ciliopathies is based to a great extent on research studying their homologues in the nematode's ciliated neurons. Moreover, proteins of the kidney filtration barrier play important roles in both correct synapse formation, mechanosensation and signal transduction in the nematode. Intriguingly, the renal cell carcinoma disease gene product von-Hippel-Lindau protein was shown to regulate lifespan in the nematode. Last but not least, the worm's excretory system itself expresses genes involved in electrolyte and osmotic homeostasis and may serve as a valuable tool to study these processes on a molecular level. C. elegans has proven to be an incredibly powerful tool in studying various aspects of renal function, development and disease and will certainly continue to do so in the future.

  18. Longitudinal imaging of Caenorhabditis elegans in a microfabricated device reveals variation in behavioral decline during aging

    OpenAIRE

    Churgin, Matthew A.; Jung, Sang-Kyu; Yu, Chih-Chieh; Chen, Xiangmei; Raizen, David M.; Fang-Yen, Christopher

    2017-01-01

    eLife digest Aging affects almost all living things, yet little is known about the biological changes that occur as we get older. Scientists often study aging in the microscopic roundworm Caenorhabditis elegans because it reproduces quickly and its lifespan is short (about 2?3 weeks on average). To date, investigations have helped to reveal genes that affect overall lifespan. However, it is not known how much these genes also affect the animal?s healthy lifespan or ?healthspan?, that is to sa...

  19. Induction of germline cell cycle arrest and apoptosis by sodium arsenite in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Shunchang; Zhao, Ye; Wu, Lijun; Tang, Mingli; Su, Caixing; Hei, Tom K; Yu, Zengliang

    2007-02-01

    The nematode Caenorhabditis elegans has been shown to be a model organism in studying aquatic toxicity. Although epidemiological studies have shown that arsenic is teratogenic and carcinogenic to humans, the lethality assay indicated that C. elegans is less sensitive to inorganic arsenic than any other organisms that have been tested thus far. In the present study, we used the more malleable germline of C. elegans as an in vivo system to investigate the genotoxic effects of arsenite. After animals were exposed to sodium arsenite at concentrations ranging from 1 microM to 0.5 mM, mitotic germ cells and germline apoptosis were scored after DAPI staining and acridine orange vital staining, respectively. DMSO rescue experiments were performed by exposing C. elegans to 0.01 mM arsenite in the presence of DMSO (0.1%) for 24 h, and reactive oxygen species (ROS) were semiquantified by CM-H(2)DCFDA vital staining. The results indicated that arsenic exposure reduced the brood size of C. elegans and caused mitotic cell cycle arrest and germline apoptosis, which, to some extent, exhibited a concentration- and time-dependent manner. The addition of 0.1% DMSO completely rescued arsenic-induced cell cycle arrest and partially suppressed germline apoptosis. Furthermore, treatment of animals with arsenite at a dose of 0.01 mM significantly increased ROS production in the intestine, which could be reduced by DMSO treatment. The present study also indicated that C. elegans might be used as an in vivo model system to study the mechanisms of arsenic-induced genotoxic effects.

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

    Science.gov (United States)

    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.

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

  2. Essential oil alloaromadendrene from mixed-type Cinnamomum osmophloeum leaves prolongs the lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Yu, Chan-Wei; Li, Wen-Hsuan; Hsu, Fu-Lan; Yen, Pei-Ling; Chang, Shang-Tzen; Liao, Vivian Hsiu-Chuan

    2014-07-02

    Cinnamomum osmophloeum Kaneh. is an indigenous tree species in Taiwan. The present study investigates phytochemical characteristics, antioxidant activities, and longevity of the essential oils from the leaves of the mixed-type C. osmophloeum tree. We demonstrate that the essential oils from leaves of mixed-type C. osmophloeum exerted in vivo antioxidant activities on Caenorhabditis elegans. In addition, minor (alloaromadendrene, 5.0%) but not major chemical components from the leaves of mixed-type C. osmophloeum have a key role against juglone-induced oxidative stress in C. elegans. Additionally, alloaromadendrene not only acts protective against oxidative stress but also prolongs the lifespan of C. elegans. Moreover, mechanistic studies show that DAF-16 is required for alloaromadendrene-mediated oxidative stress resistance and longevity in C. elegans. The results in the present study indicate that the leaves of mixed-type C. osmophloeum and essential oil alloaromadendrene have the potential for use as a source for antioxidants or treatments to delay aging.

  3. Heat-killed Lactobacillus spp. cells enhance survivals of Caenorhabditis elegans against Salmonella and Yersinia infections.

    Science.gov (United States)

    Lee, J; Choe, J; Kim, J; Oh, S; Park, S; Kim, S; Kim, Y

    2015-12-01

    This study examined the effect of feeding heat-killed Lactobacillus cells on the survival of Caenorhabditis elegans nematodes after Salmonella Typhimurium and Yersinia enterocolitica infection. The feeding of heat-killed Lactobacillus plantarum 133 (LP133) and Lactobacillus fermentum 21 (LP21) cells to nematodes was shown to significantly increase the survival rate as well as stimulate the expression of pmk-1 gene that key factor for C. elegans immunity upon infection compared with control nematodes that were only fed Escherichia coli OP50 (OP50) cells. These results suggest that heat-killed LP133 and LF21 cells exert preventive or protective effects against the Gram-negative bacteria Salm. Typhimurium and Y. enterocolitica. To better understand the mechanisms underlying the LF21-mediated and LP133-mediated protection against bacterial infection in nematodes, transcriptional profiling was performed for each experimental group. These experiments showed that genes related to energy generation and ageing, regulators of insulin/IGF-1-like signalling, DAF genes, oxidation and reduction processes, the defence response and/or the innate immune response, and neurological processes were upregulated in nematodes that had been fed heat-killed Lactobacillus cells compared with nematodes that had been fed E. coli cells. In this study, the feeding of heat-killed Lactobacillus bacteria to Caenorhabditis elegans nematodes was shown to decrease infection by Gram-negative bacteria and increase the host lifespan. C. elegans has a small, well-organized genome and is an excellent in vivo model organism; thus, these results will potentially shed light on important Lactobacillus-host interactions. © 2015 The Society for Applied Microbiology.

  4. IMPACT OF FOOD AND FOLATE SUPPLEMENTATION DURING Salmonella TYPHI INFECTION IN Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Bhagavathi Sundaram Sivamaruthi

    2012-06-01

    Full Text Available Caenorhabditis elegans is an instructive and suitable model for studying pathogenesis of almost all human pathogens. Salmonella Typhi is gram-negative facultative intracellular anaerobe that causes several pathetic infections. Necessary enriched nutrient ingestion during pathological conditions may reduce the harshness of the infection. We investigated the impact of folate and food supplementation during S. Typhi infection on the model system, C. elegans. Our data indicated that folate supplementation (10 µg increases the lifespan of S. Typhi infected C. elegans up to 20%. In combination with laboratory food source E. coli OP50, folate increases the infected the worm’s lifespan to 40%. The wild type C. elegans infected by S. Typhi died with the LT50 of 60 ± 12 h. The LT50 of S. Typhi infected folt-1 mutant strain VC959 was 96 ± 6 h. However, the folate supplemented mutant worms exhibited an extended life with LT50 of 120 ± 6 h. The short time exposure and pharyngeal pumping studies confirmed that folt-1 mutant worm exhibited increased survival rate during pathogenic course at significant level when compared to wild-type. Our data revealed that folt-1 plays a significant role in host defense system against S. Typhi infection and the folate supplementation in combination with food increases the host survival during S. Typhi infection.

  5. Description of International Caenorhabditis elegans Experiment first flight (ICE-FIRST)

    Science.gov (United States)

    Szewczyk, N. J.; Tillman, J.; Conley, C. A.; Granger, L.; Segalat, L.; Higashitani, A.; Honda, S.; Honda, Y.; Kagawa, H.; Adachi, R.; Higashibata, A.; Fujimoto, N.; Kuriyama, K.; Ishioka, N.; Fukui, K.; Baillie, D.; Rose, A.; Gasset, G.; Eche, B.; Chaput, D.; Viso, M.

    2008-09-01

    Traveling, living and working in space is now a reality. The number of people and length of time in space is increasing. With new horizons for exploration it becomes more important to fully understand and provide countermeasures to the effects of the space environment on the human body. In addition, space provides a unique laboratory to study how life and physiologic functions adapt from the cellular level to that of the entire organism. Caenorhabditis elegans is a genetic model organism used to study physiology on Earth. Here we provide a description of the rationale, design, methods, and space culture validation of the ICE-FIRST payload, which engaged C. elegans researchers from four nations. Here we also show C. elegans growth and development proceeds essentially normally in a chemically defined liquid medium on board the International Space Station (10.9 day round trip). By setting flight constraints first and bringing together established C. elegans researchers second, we were able to use minimal stowage space to successfully return a total of 53 independent samples, each containing more than a hundred individual animals, to investigators within one year of experiment concept. We believe that in the future, bringing together individuals with knowledge of flight experiment operations, flight hardware, space biology, and genetic model organisms should yield similarly successful payloads.

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

    Directory of Open Access Journals (Sweden)

    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

  7. In Vivo Detection of Reactive Oxygen Species and Redox Status in Caenorhabditis elegans

    Science.gov (United States)

    Smolders, Arne; Back, Patricia; De Henau, Sasha

    2016-01-01

    Abstract Significance: Due to its large families of redox-active enzymes, genetic amenability, and complete transparency, the nematode Caenorhabditis elegans has the potential to become an important model for the in vivo study of redox biology. Recent Advances: The recent development of several genetically encoded ratiometric reactive oxygen species (ROS) and redox sensors has revolutionized the quantification and precise localization of ROS and redox signals in living organisms. Only few exploratory studies have applied these sensors in C. elegans and undoubtedly much remains to be discovered in this model. As a follow-up to our recent findings that the C. elegans somatic gonad uses superoxide and hydrogen peroxide (H2O2) signals to communicate with the germline, we here analyze the patterns of H2O2 inside the C. elegans germline. Critical Issues: Despite the advantages of genetically encoded ROS and redox sensors over classic chemical sensors, still several general as well as C. elegans-specific issues need to be addressed. The major concerns for the application of these sensors in C. elegans are (i) decreased vitality of some reporter strains, (ii) interference of autofluorescent compartments with the sensor signal, and (iii) the use of immobilization methods that do not influence the worm's redox physiology. Future Directions: We propose that several of the current issues may be solved by designing reporter strains carrying single copies of codon-optimized sensors. Preferably, these sensors should have their emission wavelengths in the red region, where autofluorescence is absent. Worm analysis could be optimized using four-dimensional ratiometric fluorescence microscopy of worms immobilized in microfluidic chips. Antioxid. Redox Signal. 25, 577–592. PMID:27306519

  8. Metabolomic signature associated with reproduction-regulated aging in Caenorhabditis elegans.

    Science.gov (United States)

    Wan, Qin-Li; Shi, Xiaohuo; Liu, Jiangxin; Ding, Ai-Jun; Pu, Yuan-Zhu; Li, Zhigang; Wu, Gui-Sheng; Luo, Huai-Rong

    2017-02-06

    In Caenorhabditis elegans (C. elegans), ablation of germline stem cells (GSCs) leads to infertility, which extends lifespan. It has been reported that aging and reproduction are both inextricably associated with metabolism. However, few studies have investigated the roles of polar small molecules metabolism in regulating longevity by reproduction. In this work, we combined the nuclear magnetic resonance (NMR) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to profile the water-soluble metabolome in C. elegans. Comparing the metabolic fingerprint between two physiological ages among different mutants, our results demonstrate that aging is characterized by metabolome remodeling and metabolic decline. In addition, by analyzing the metabolic profiles of long-lived germline-less glp-1 mutants, we discovered that glp-1 mutants regulate the levels of many age-variant metabolites to attenuate aging, including elevated concentrations of the pyrimidine and purine metabolism intermediates and decreased concentrations of the citric acid cycle intermediates. Interestingly, by analyzing the metabolome of daf-16;glp-1 double mutants, our results revealed that some metabolic exchange contributing to germline-mediated longevity was mediated by transcription factor FOXO/DAF-16, including pyrimidine metabolism and the TCA cycle. Based on a comprehensive metabolic analysis, we provide novel insight into the relationship between longevity and metabolism regulated by germline signals in C. elegans.

  9. 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.

  10. Aging Effects of Caenorhabditis elegans Ryanodine Receptor Variants Corresponding to Human Myopathic Mutations

    Directory of Open Access Journals (Sweden)

    Katie Nicoll Baines

    2017-05-01

    Full Text Available Delaying the decline in skeletal muscle function will be critical to better maintenance of an active lifestyle in old age. The skeletal muscle ryanodine receptor, the major intracellular membrane channel through which calcium ions pass to elicit muscle contraction, is central to calcium ion balance and is hypothesized to be a significant factor for age-related decline in muscle function. The nematode Caenorhabditis elegans is a key model system for the study of human aging, and strains were generated with modified C. elegans ryanodine receptors corresponding to human myopathic variants linked with malignant hyperthermia and related conditions. The altered response of these strains to pharmacological agents reflected results of human diagnostic tests for individuals with these pathogenic variants. Involvement of nerve cells in the C. elegans responses may relate to rare medical symptoms concerning the central nervous system that have been associated with ryanodine receptor variants. These single amino acid modifications in C. elegans also conferred a reduction in lifespan and an accelerated decline in muscle integrity with age, supporting the significance of ryanodine receptor function for human aging.

  11. An Evolutionarily Conserved Pathway Essential for Orsay Virus Infection of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Hongbing Jiang

    2017-09-01

    Full Text Available Many fundamental biological discoveries have been made in Caenorhabditis elegans. The discovery of Orsay virus has enabled studies of host-virus interactions in this model organism. To identify host factors critical for Orsay virus infection, we designed a forward genetic screen that utilizes a virally induced green fluorescent protein (GFP reporter. Following chemical mutagenesis, two Viro (virus induced reporter off mutants that failed to express GFP were mapped to sid-3, a nonreceptor tyrosine kinase, and B0280.13 (renamed viro-2, an ortholog of human Wiskott-Aldrich syndrome protein (WASP. Both mutants yielded Orsay virus RNA levels comparable to that of the residual input virus, suggesting that they are not permissive for Orsay virus replication. In addition, we demonstrated that both genes affect an early prereplication stage of Orsay virus infection. Furthermore, it is known that the human ortholog of SID-3, activated CDC42-associated kinase (ACK1/TNK2, is capable of phosphorylating human WASP, suggesting that VIRO-2 may be a substrate for SID-3 in C. elegans. A targeted RNA interference (RNAi knockdown screen further identified the C. elegans gene nck-1, which has a human ortholog that interacts with TNK2 and WASP, as required for Orsay virus infection. Thus, genetic screening in C. elegans identified critical roles in virus infection for evolutionarily conserved genes in a known human pathway.

  12. Metabolomic signature associated with reproduction-regulated aging in Caenorhabditis elegans

    Science.gov (United States)

    Wan, Qin-Li; Shi, Xiaohuo; Liu, Jiangxin; Ding, Ai-Jun; Pu, Yuan-Zhu; Li, Zhigang; Wu, Gui-Sheng; Luo, Huai-Rong

    2017-01-01

    In Caenorhabditis elegans (C. elegans), ablation of germline stem cells (GSCs) leads to infertility, which extends lifespan. It has been reported that aging and reproduction are both inextricably associated with metabolism. However, few studies have investigated the roles of polar small molecules metabolism in regulating longevity by reproduction. In this work, we combined the nuclear magnetic resonance (NMR) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to profile the water-soluble metabolome in C. elegans. Comparing the metabolic fingerprint between two physiological ages among different mutants, our results demonstrate that aging is characterized by metabolome remodeling and metabolic decline. In addition, by analyzing the metabolic profiles of long-lived germline-less glp-1 mutants, we discovered that glp-1 mutants regulate the levels of many age-variant metabolites to attenuate aging, including elevated concentrations of the pyrimidine and purine metabolism intermediates and decreased concentrations of the citric acid cycle intermediates. Interestingly, by analyzing the metabolome of daf-16;glp-1 double mutants, our results revealed that some metabolic exchange contributing to germline-mediated longevity was mediated by transcription factor FOXO/DAF-16, including pyrimidine metabolism and the TCA cycle. Based on a comprehensive metabolic analysis, we provide novel insight into the relationship between longevity and metabolism regulated by germline signals in C. elegans PMID:28177875

  13. Analysis of the Caenorhabditis elegans innate immune response to Coxiella burnetii.

    Science.gov (United States)

    Battisti, James M; Watson, Lance A; Naung, Myo T; Drobish, Adam M; Voronina, Ekaterina; Minnick, Michael F

    2017-02-01

    The nematode Caenorhabditis elegans is well established as a system for characterization and discovery of molecular mechanisms mediating microbe-specific inducible innate immune responses to human pathogens. Coxiella burnetii is an obligate intracellular bacterium that causes a flu-like syndrome in humans (Q fever), as well as abortions in domesticated livestock, worldwide. Initially, when wild type C. elegans (N2 strain) was exposed to mCherry-expressing C. burnetii (CCB) a number of overt pathological manifestations resulted, including intestinal distension, deformed anal region and a decreased lifespan. However, nematodes fed autoclave-killed CCB did not exhibit these symptoms. Although vertebrates detect C. burnetii via TLRs, pathologies in tol-1(-) mutant nematodes were indistinguishable from N2, and indicate nematodes do not employ this orthologue for detection of C. burnetii. sek-1(-) MAP kinase mutant nematodes succumbed to infection faster, suggesting that this signaling pathway plays a role in immune activation, as previously shown for orthologues in vertebrates during a C. burnetii infection. C. elegans daf-2(-) mutants are hyper-immune and exhibited significantly reduced pathological consequences during challenge. Collectively, these results demonstrate the utility of C. elegans for studying the innate immune response against C. burnetii and could lead to discovery of novel methods for prevention and treatment of disease in humans and livestock.

  14. 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. Copyright © 2016 by the Genetics Society of America.

  15. Identification of a gonadotropin-releasing hormone receptor orthologue in Caenorhabditis elegans

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    Sgro Jean-Yves

    2006-11-01

    Full Text Available Abstract Background The Caenorhabditis elegans genome is known to code for at least 1149 G protein-coupled receptors (GPCRs, but the GPCR(s critical to the regulation of reproduction in this nematode are not yet known. This study examined whether GPCRs orthologous to human gonadotropin-releasing hormone receptor (GnRHR exist in C. elegans. Results Our sequence analyses indicated the presence of two proteins in C. elegans, one of 401 amino acids [GenBank: NP_491453; WormBase: F54D7.3] and another of 379 amino acids [GenBank: NP_506566; WormBase: C15H11.2] with 46.9% and 44.7% nucleotide similarity to human GnRHR1 and GnRHR2, respectively. Like human GnRHR1, structural analysis of the C. elegans GnRHR1 orthologue (Ce-GnRHR predicted a rhodopsin family member with 7 transmembrane domains, G protein coupling sites and phosphorylation sites for protein kinase C. Of the functionally important amino acids in human GnRHR1, 56% were conserved in the C. elegans orthologue. Ce-GnRHR was actively transcribed in adult worms and immunoanalyses using antibodies generated against both human and C. elegans GnRHR indicated the presence of a 46-kDa protein, the calculated molecular mass of the immature Ce-GnRHR. Ce-GnRHR staining was specifically localized to the germline, intestine and pharynx. In the germline and intestine, Ce-GnRHR was localized specifically to nuclei as revealed by colocalization with a DNA nuclear stain. However in the pharynx, Ce-GnRHR was localized to the myofilament lattice of the pharyngeal musculature, suggesting a functional role for Ce-GnRHR signaling in the coupling of food intake with reproduction. Phylogenetic analyses support an early evolutionary origin of GnRH-like receptors, as evidenced by the hypothesized grouping of Ce-GnRHR, vertebrate GnRHRs, a molluscan GnRHR, and the adipokinetic hormone receptors (AKHRs and corazonin receptors of arthropods. Conclusion This is the first report of a GnRHR orthologue in C. elegans, which

  16. Sequence signatures of nucleosome positioning in Caenorhabditis elegans.

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    Chen, Kaifu; Wang, Lei; Yang, Meng; Liu, Jiucheng; Xin, Chengqi; Hu, Songnian; Yu, Jun

    2010-06-01

    Our recent investigation in the protist Trichomonas vaginalis suggested a DNA sequence periodicity with a unit length of 120.9 nt, which represents a sequence signature for nucleosome positioning. We now extended our observation in higher eukaryotes and identified a similar periodicity of 175 nt in length in Caenorhabditis elegans. In the process of defining the sequence compositional characteristics, we found that the 10.5-nt periodicity, the sequence signature of DNA double helix, may not be sufficient for cross-nucleosome positioning but provides essential guiding rails to facilitate positioning. We further dissected nucleosome-protected sequences and identified a strong positive purine (AG) gradient from the 5'-end to the 3'-end, and also learnt that the nucleosome-enriched regions are GC-rich as compared to the nucleosome-free sequences as purine content is positively correlated with GC content. Sequence characterization allowed us to develop a hidden Markov model (HMM) algorithm for decoding nucleosome positioning computationally, and based on a set of training data from the fifth chromosome of C. elegans, our algorithm predicted 60%-70% of the well-positioned nucleosomes, which is 15%-20% higher than random positioning. We concluded that nucleosomes are not randomly positioned on DNA sequences and yet bind to different genome regions with variable stability, well-positioned nucleosomes leave sequence signatures on DNA, and statistical positioning of nucleosomes across genome can be decoded computationally based on these sequence signatures. Copyright 2010 Beijing Genomics Institute. Published by Elsevier Ltd. All rights reserved.

  17. Metabolome and proteome changes with aging in Caenorhabditis elegans

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    Copes, Neil; Edwards, Clare; Chaput, Dale; Saifee, Mariam; Barjuca, Iosif; Nelson, Daniel; Paraggio, Alyssa; Saad, Patrick; Lipps, David; Stevens, Stanley M.; Bradshaw, Patrick C.

    2015-01-01

    To expand the understanding of aging in the model organism Caenorhabditis elegans, global quantification of metabolite and protein levels in young and aged nematodes was performed using mass spectrometry. With age there was a decreased abundance of proteins functioning in transcription termination, mRNA degradation, mRNA stability, protein synthesis, and proteasomal function. Furthermore there was altered S-adenosyl methionine metabolism as well as a decreased abundance of the S-adenosyl methionine synthetase (SAMS-1) protein. Other aging-related changes included alterations in free fatty acid levels and composition, decreased levels of ribosomal proteins, decreased levels of NADP-dependent isocitrate dehydrogenase (IDH1), a shift in the cellular redox state, an increase in sorbitol content, alterations in free amino acid levels, and indications of altered muscle function and sarcoplasmic reticulum Ca2+ homeostasis. There were also decreases in pyrimidine and purine metabolite levels, most markedly nitrogenous bases. Supplementing the culture medium with cytidine (a pyrimidine nucleoside) or hypoxanthine (a purine base) increased lifespan slightly, suggesting that aging-induced alterations in ribonucleotide metabolism affect lifespan. An age-related increase in body size, lipotoxicity from ectopic yolk lipoprotein accumulation, a decline in NAD+ levels, and mitochondrial electron transport chain dysfunction may explain many of these changes. In addition, dietary restriction in aged worms resulting from sarcopenia of the pharyngeal pump likely decreases the abundance of SAMS-1, possibly leading to decreased phosphatidylcholine levels, larger lipid droplets, and ER and mitochondrial stress. The complementary use of proteomics and metabolomics yielded unique insights into the molecular processes altered with age in C. elegans. PMID:26390854

  18. Metabolome and proteome changes with aging in Caenorhabditis elegans.

    Science.gov (United States)

    Copes, Neil; Edwards, Clare; Chaput, Dale; Saifee, Mariam; Barjuca, Iosif; Nelson, Daniel; Paraggio, Alyssa; Saad, Patrick; Lipps, David; Stevens, Stanley M; Bradshaw, Patrick C

    2015-12-01

    To expand the understanding of aging in the model organism Caenorhabditis elegans, global quantification of metabolite and protein levels in young and aged nematodes was performed using mass spectrometry. With age, there was a decreased abundance of proteins functioning in transcription termination, mRNA degradation, mRNA stability, protein synthesis, and proteasomal function. Furthermore, there was altered S-adenosyl methionine metabolism as well as a decreased abundance of the S-adenosyl methionine synthetase (SAMS-1) protein. Other aging-related changes included alterations in free fatty acid levels and composition, decreased levels of ribosomal proteins, decreased levels of NADP-dependent isocitrate dehydrogenase (IDH1), a shift in the cellular redox state, an increase in sorbitol content, alterations in free amino acid levels, and indications of altered muscle function and sarcoplasmic reticulum Ca(2+) homeostasis. There were also decreases in pyrimidine and purine metabolite levels, most markedly nitrogenous bases. Supplementing the culture medium with cytidine (a pyrimidine nucleoside) or hypoxanthine (a purine base) increased lifespan slightly, suggesting that aging-induced alterations in ribonucleotide metabolism affect lifespan. An age-related increase in body size, lipotoxicity from ectopic yolk lipoprotein accumulation, a decline in NAD(+) levels, and mitochondrial electron transport chain dysfunction may explain many of these changes. In addition, dietary restriction in aged worms resulting from sarcopenia of the pharyngeal pump likely decreases the abundance of SAMS-1, possibly leading to decreased phosphatidylcholine levels, larger lipid droplets, and ER and mitochondrial stress. The complementary use of proteomics and metabolomics yielded unique insights into the molecular processes altered with age in C. elegans. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Growth of Caenorhabditis elegans in Defined Media Is Dependent on Presence of Particulate Matter.

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    Flavel, Matthew R; Mechler, Adam; Shahmiri, Mahdi; Mathews, Elizabeth R; Franks, Ashley E; Chen, Weisan; Zanker, Damien; Xian, Bo; Gao, Shan; Luo, Jing; Tegegne, Surafel; Doneski, Christian; Jois, Markandeya

    2018-02-02

    Caenorhabditis elegans are typically cultured in a monoxenic medium consisting of live bacteria. However, this introduces a secondary organism to experiments, and restricts the manipulation of the nutritional environment. Due to the intricate link between genes and environment, greater control and understanding of nutritional factors are required to push the C. elegans field into new areas. For decades, attempts to develop a chemically defined, axenic medium as an alternative for culturing C. elegans have been made. However, the mechanism by which the filter feeder C. elegans obtains nutrients from these liquid media is not known. Using a fluorescence-activated cell sorting based approach, we demonstrate growth in all past axenic C. elegans media to be dependent on the presence of previously unknown particles. This particle requirement of C. elegans led to development of liposome-based, nanoparticle culturing that allows full control of nutrients delivered to C. elegans. Copyright © 2018 Flavel et al.

  20. Distinct molecular targets including SLO-1 and gap junctions are engaged across a continuum of ethanol concentrations in Caenorhabditis elegans

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    Dillon, James; Andrianakis, Ioannis; Mould, Richard; Ient, Ben; Liu, Wei; James, Christopher; O'Connor, Vincent; Holden-Dye, Lindy

    2013-01-01

    Ethanol (alcohol) interacts with diverse molecular effectors across a range of concentrations in the brain, eliciting intoxication through to sedation. Invertebrate models including the nematode worm Caenorhabditis elegans have been deployed for molecular genetic studies to inform on key components of these alcohol signaling pathways. C. elegans studies have typically employed external dosing with high (>250 mM) ethanol concentrations: A careful analysis of responses to low concentrations is lacking. Using the C. elegans pharyngeal system as a paradigm, we report a previously uncharacterized continuum of cellular and behavioral responses to ethanol from low (10 mM) to high (300 mM) concentrations. The complexity of these responses indicates that the pleiotropic action of ethanol observed in mammalian brain is conserved in this invertebrate model. We investigated two candidate ethanol effectors, the calcium-activated K+ channel SLO-1 and gap junctions, and show that they contribute to, but are not sole determinants of, the low- and high-concentration effects, respectively. Notably, this study shows cellular and whole organismal behavioral responses to ethanol in C. elegans that directly equate to intoxicating through to supralethal blood alcohol concentrations in humans and provides an important benchmark for interpretation of paradigms that seek to inform on human alcohol use disorders.—Dillon, J., Andrianakis, I., Mould, R., Ient, B., Liu, W., James, C., O'Connor, V., Holden-Dye, L. Distinct molecular targets including SLO-1 and gap junctions are engaged across a continuum of ethanol concentrations in Caenorhabditis elegans. PMID:23882127

  1. 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

  2. The nematode Caenorhabditis elegans survives subfreezing temperatures in an isochoric system

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    Mikus, Hannah; Miller, Alexander [Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States); Nastase, Gabriel, E-mail: traznasa@gmail.com [Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States); Department of Building Services, Transilvania University of Brasov, Brasov, 500036 (Romania); Serban, Alexandru [Department of Building Services, Transilvania University of Brasov, Brasov, 500036 (Romania); Shapira, Michael [Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720 (United States); Rubinsky, Boris, E-mail: rubinsky@berkeley.edu [Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States)

    2016-08-26

    This study is the first experimental evidence showing that a living multicellular organism, the nematode Caenorhabditis elegans, can survive subfreezing temperatures in an isochoric (constant volume) thermodynamic system, while immersed in a simple isotonic solution, without the addition of cryoprotectants. Some of the test conditions were more extreme than those found at the ice/water interface of the Antarctic subglacial Vostok lake. On earth, life takes place in an isobaric (constant pressure) environment. In isobaric systems, subfreezing temperature survival of organisms in nature and subfreezing temperature preservation of living material for biotechnology and medicine, is made possible by use of cryoprotective chemicals additives. Our theoretical thermodynamic studies suggested that in an isochoric system, living biological material could survive subfreezing temperatures, without any cryoprotective chemicals. By confirming the theoretical predictions, this paper suggests a new technology for subfreezing preservation of cells, organs and organisms of possible value for biotechnology and medicine as well as new possible mechanisms of living organism survival in nature. - Highlights: • Preservation of biological materials at, subfreezing temperatures, in an isochoric system, is demonstrated. • Experiments were performed with Caenorhabditis elegans to pressures of 65 MPa and temperatures of −6 °C. • Isochoric subfreezing temperature is a new preservation method that does not require the use of cryoprotectants.

  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. IL-17 is a neuromodulator of Caenorhabditis elegans sensory responses.

    Science.gov (United States)

    Chen, Changchun; Itakura, Eisuke; Nelson, Geoffrey M; Sheng, Ming; Laurent, Patrick; Fenk, Lorenz A; Butcher, Rebecca A; Hegde, Ramanujan S; de Bono, Mario

    2017-02-02

    Interleukin-17 (IL-17) is a major pro-inflammatory cytokine: it mediates responses to pathogens or tissue damage, and drives autoimmune diseases. Little is known about its role in the nervous system. Here we show that IL-17 has neuromodulator-like properties in Caenorhabditis elegans. IL-17 can act directly on neurons to alter their response properties and contribution to behaviour. Using unbiased genetic screens, we delineate an IL-17 signalling pathway and show that it acts in the RMG hub interneurons. Disrupting IL-17 signalling reduces RMG responsiveness to input from oxygen sensors, and renders sustained escape from 21% oxygen transient and contingent on additional stimuli. Over-activating IL-17 receptors abnormally heightens responses to 21% oxygen in RMG neurons and whole animals. IL-17 deficiency can be bypassed by optogenetic stimulation of RMG. Inducing IL-17 expression in adults can rescue mutant defects within 6 h. These findings reveal a non-immunological role of IL-17 modulating circuit function and behaviour.

  5. 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.

  6. More Sex-Determination Mutants of CAENORHABDITIS ELEGANS

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    Hodgkin, Jonathan

    1980-01-01

    Sex determination in Caenorhabditis elegans is controlled by the X chromosome: autosome ratio, i.e. 2A;XX animals are hermaphrodite, and 2A;XO animals are male. A procedure for isolating 2A;XO animals that are transformed into hermaphrodites has been developed. Nine mutations causing this transformation have been obtained: eight are recessive, and all of these fall into a new autosomal complementation group, her-1 V. The remaining mutation (her-2) is dominant and has a genetic map location similar to that of tra-1 III. Recessive mutations of tra-1 cause the reverse transformation, transforming 2A;XX animals into males. Therefore, the her-2 mutation may result in constitutive expression of tra-1. Mutations in her-1 are without effect on XX animals, but the her-2 mutation prevents sperm production in both XX and XO animals, in addition to its effect on the sexual phenotype of XO animals. The epistatic relationships between tra and her genes are used to deduce a model for the action of these genes in controlling sex determination. PMID:7262542

  7. Calcineurin Antagonizes AMPK to Regulate Lipolysis in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Yanli; Xie, Cangsang; Diao, Zhiqing; Liang, Bin

    2017-06-26

    Calcineurin is a calcium- and calmodulin-dependent serine/threonine protein phosphatase, and the target of immunosuppressive agent tacrolimus (TAC). The dysfunction of calcineurin, or clinical applications of tacrolimus, have been reported to be associated with dyslipidemia. The underlying mechanisms of calcineurin and tacrolimus in lipid metabolism are largely unknown. Here, we showed that mutations of tax-6 and cnb-1, which respectively encode the catalytic subunit and the regulatory subunit of calcineurin, together with tacrolimus treatment, consistently led to decreased fat accumulation and delayed growth in the nematode Caenorhabditis elegans. In contrast, disruption of the AMP-activated protein kinase (AMPK) encoded by aak-1 and aak-2 reversed the above effects in worms. Moreover, calcineurin deficiency and tacrolimus treatment consistently activated the transcriptional expression of the lipolytic gene atgl-1, encoding triglyceride lipase. Furthermore, RNAi knockdown of atgl-1 recovered the decreased fat accumulation in both calcineurin deficient and tacrolimus treated worms. Collectively, our results reveal that immunosuppressive agent tacrolimus and their target calcineurin may antagonize AMPK to regulate ATGL and lipolysis, thereby providing potential therapy for the application of immunosuppressive agents.

  8. Calcineurin Antagonizes AMPK to Regulate Lipolysis in Caenorhabditis elegans

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    Yanli Wang

    2017-06-01

    Full Text Available Calcineurin is a calcium- and calmodulin-dependent serine/threonine protein phosphatase, and the target of immunosuppressive agent tacrolimus (TAC. The dysfunction of calcineurin, or clinical applications of tacrolimus, have been reported to be associated with dyslipidemia. The underlying mechanisms of calcineurin and tacrolimus in lipid metabolism are largely unknown. Here, we showed that mutations of tax-6 and cnb-1, which respectively encode the catalytic subunit and the regulatory subunit of calcineurin, together with tacrolimus treatment, consistently led to decreased fat accumulation and delayed growth in the nematode Caenorhabditis elegans. In contrast, disruption of the AMP-activated protein kinase (AMPK encoded by aak-1 and aak-2 reversed the above effects in worms. Moreover, calcineurin deficiency and tacrolimus treatment consistently activated the transcriptional expression of the lipolytic gene atgl-1, encoding triglyceride lipase. Furthermore, RNAi knockdown of atgl-1 recovered the decreased fat accumulation in both calcineurin deficient and tacrolimus treated worms. Collectively, our results reveal that immunosuppressive agent tacrolimus and their target calcineurin may antagonize AMPK to regulate ATGL and lipolysis, thereby providing potential therapy for the application of immunosuppressive agents.

  9. 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

  10. Antiviral RNA Interference against Orsay Virus Is neither Systemic nor Transgenerational in Caenorhabditis elegans.

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    Ashe, Alyson; Sarkies, Peter; Le Pen, Jérémie; Tanguy, Mélanie; Miska, Eric A

    2015-12-01

    Antiviral RNA-mediated silencing (RNA interference [RNAi]) acts as a powerful innate immunity defense in plants, invertebrates, and mammals. In Caenorhabditis elegans, RNAi is systemic; i.e., RNAi silencing signals can move between cells and tissues. Furthermore, RNAi effects can be inherited transgenerationally and may last for many generations. Neither the biological relevance of systemic RNAi nor transgenerational RNAi is currently understood. Here we examined the role of both pathways in the protection of C. elegans from viral infection. We studied the Orsay virus, a positive-strand RNA virus related to Nodaviridae and the first and only virus known to infect C. elegans. Immunity to Orsay virus infection requires the RNAi pathway. Surprisingly, we found that genes required for systemic or transgenerational RNAi did not have a role in antiviral defense. Furthermore, we found that Orsay virus infection did not elicit a systemic RNAi response even when a target for RNAi was provided by using transgenes. Finally, we show that viral siRNAs, the effectors of RNAi, are not inherited to a level that provides any significant resistance to viral infection in the next generation. We conclude that systemic or transgenerational RNAi does not play a role in the defense against natural Orsay virus infection. Furthermore, our data suggest that there is a qualitative difference between experimental RNAi and antiviral RNAi. Our data are consistent with a model of systemic and transgenerational RNAi that requires a nuclear or germ line component that is lacking in almost all RNA virus infections. Since its discovery in Caenorhabditis elegans, RNAi has proven a valuable scientific tool in many organisms. In C. elegans, exogenous RNAi spreads throughout the organism and can be passed between generations; however, there has been controversy as to the endogenous role(s) that the RNAi pathway plays. One endogenous role for which spreading both within the infected organism and between

  11. 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.

  12. 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. Copyright © 2015 John Wiley & Sons, Ltd.

  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. Shigella flexneri Infection in Caenorhabditis elegans: Cytopathological Examination and Identification of Host Responses

    Science.gov (United States)

    George, Divya T.; Behm, Carolyn A.; Hall, David H.; Mathesius, Ulrike; Rug, Melanie; Nguyen, Ken C. Q.; Verma, Naresh K.

    2014-01-01

    The Gram-negative bacterium Shigella flexneri is the causative agent of shigellosis, a diarrhoeal disease also known as bacillary dysentery. S. flexneri infects the colonic and rectal epithelia of its primate host and induces a cascade of inflammatory responses that culminates in the destruction of the host intestinal lining. Molecular characterization of host-pathogen interactions in this infection has been challenging due to the host specificity of S. flexneri strains, as it strictly infects humans and non-human primates. Recent studies have shown that S. flexneri infects the soil dwelling nematode Caenorhabditis elegans, however, the interactions between S. flexneri and C. elegans at the cellular level and the cause of nematode death are unknown. Here we attempt to gain insight into the complex host-pathogen interactions between S. flexneri and C. elegans. Using transmission electron microscopy, we show that live S. flexneri cells accumulate in the nematode intestinal lumen, produce outer membrane vesicles and invade nematode intestinal cells. Using two-dimensional differential in-gel electrophoresis we identified host proteins that are differentially expressed in response to S. flexneri infection. Four of the identified genes, aco-1, cct-2, daf-19 and hsp-60, were knocked down using RNAi and ACO-1, CCT-2 and DAF-19, which were identified as up-regulated in response to S. flexneri infection, were found to be involved in the infection process. aco-1 RNAi worms were more resistant to S. flexneri infection, suggesting S. flexneri-mediated disruption of host iron homeostasis. cct-2 and daf-19 RNAi worms were more susceptible to infection, suggesting that these genes are induced as a protective mechanism by C. elegans. These observations further our understanding of the processes involved in S. flexneri infection of C. elegans, which is immensely beneficial to the routine use of this new in vivo model to study S. flexneri pathogenesis. PMID:25187942

  15. 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.

  16. Glucose 6-phosphate dehydrogenase deficiency enhances germ cell apoptosis and causes defective embryogenesis in Caenorhabditis elegans

    Science.gov (United States)

    Yang, H-C; Chen, T-L; Wu, Y-H; Cheng, K-P; Lin, Y-H; Cheng, M-L; Ho, H-Y; Lo, S J; Chiu, D T-Y

    2013-01-01

    Glucose 6-phosphate dehydrogenase (G6PD) deficiency, known as favism, is classically manifested by hemolytic anemia in human. More recently, it has been shown that mild G6PD deficiency moderately affects cardiac function, whereas severe G6PD deficiency leads to embryonic lethality in mice. How G6PD deficiency affects organisms has not been fully elucidated due to the lack of a suitable animal model. In this study, G6PD-deficient Caenorhabditis elegans was established by RNA interference (RNAi) knockdown to delineate the role of G6PD in animal physiology. Upon G6PD RNAi knockdown, G6PD activity was significantly hampered in C. elegans in parallel with increased oxidative stress and DNA oxidative damage. Phenotypically, G6PD-knockdown enhanced germ cell apoptosis (2-fold increase), reduced egg production (65% of mock), and hatching (10% of mock). To determine whether oxidative stress is associated with G6PD knockdown-induced reproduction defects, C. elegans was challenged with a short-term hydrogen peroxide (H2O2). The early phase egg production of both mock and G6PD-knockdown C. elegans were significantly affected by H2O2. However, H2O2-induced germ cell apoptosis was more dramatic in mock than that in G6PD-deficient C. elegans. To investigate the signaling pathways involved in defective oogenesis and embryogenesis caused by G6PD knockdown, mutants of p53 and mitogen-activated protein kinase (MAPK) pathways were examined. Despite the upregulation of CEP-1 (p53), cep-1 mutation did not affect egg production and hatching in G6PD-deficient C. elegans. Neither pmk-1 nor mek-1 mutation significantly affected egg production, whereas sek-1 mutation further decreased egg production in G6PD-deficient C. elegans. Intriguingly, loss of function of sek-1 or mek-1 dramatically rescued defective hatching (8.3- and 9.6-fold increase, respectively) induced by G6PD knockdown. Taken together, these findings show that G6PD knockdown reduces egg production and hatching in C. elegans

  17. Deltamethrin increases the fat accumulation in 3T3-L1 adipocytes and Caenorhabditis elegans.

    Science.gov (United States)

    Shen, Peiyi; Hsieh, Tsung-Hsiu; Yue, Yiren; Sun, Quancai; Clark, John M; Park, Yeonhwa

    2017-03-01

    Research has shown that permethrin, a Type-I pyrethroid, increases triglyceride (fat) accumulation in adipocytes. Little is known, however, about any similar effect of deltamethrin, a Type-II pyrethroid, which produces a distinct syndrome of poisoning in mammals compared with permethrin. This study was therefore aimed to explore the role of deltamethrin on fat accumulation in 3T3-L1 adipocytes and Caenorhabditis elegans. Deltamethrin (10 μM) significantly increased the fat accumulation in 3T3-L1 adipocytes and wild type C. elegans compared to respective controls. Deltamethrin decreased the ratio of phosphorylated AMP-activated kinase (pAMPKα) over AMPKα and phosphorylated acetyl-CoA carboxylase (ACC) over ACC, while it increased expression of CCAAT/enhancer-binding protein (C/EBPα) and peroxisome proliferator-activated receptor-γ (PPARγ) in 3T3-L1 adipocytes. Similarly, deltamethrin potentiated fat accumulation in C. elegans without affecting growth or pharyngeal pumping rate. Moreover, deltamethrin significantly reduced the total progeny number and locomotive activities in C. elegans in a dose-dependent manner. Deltamethrin increased fat accumulation via aak-2 (an ortholog of AMPKα) and nhr-49 (a homolog of peroxisome proliferator-activated receptor-α and also downstream target of aak-2) mediated mechanisms. The current work is the first report of the effects of deltamethrin on increased fat storage by 3T3- L1 adipocytes and C. elegans via aak-2 (AMPKα ortholog)-mediated mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Longevity effect of a polysaccharide from Chlorophytum borivilianum on Caenorhabditis elegans and Saccharomyces cerevisiae

    Science.gov (United States)

    Pannakal, Steve Thomas; Jäger, Sibylle; Duranton, Albert; Tewari, Amit; Saha, Subarna; Radhakrishnan, Aneesha; Roy, Nita; Kuntz, Jean François; Fermas, Soraya; Mellor, Jane; Breton, Lionel

    2017-01-01

    The traditional Indian medicine, Ayurveda, provides insights and practical solutions towards a healthy life style. Rasayana is a branch of Ayurveda known for preserving and promoting health, enhancing the quality of life and delaying the aging process. In the traditional knowledge, the Rasayana herb, Chlorophytum borivilianum (C. borivilanum) is regarded as a general health promoting tonic that delays aging and increases lifespan, cognitive function and physical strength. Aging is a complex and multifactorial physiological phenomenon that manifests itself over a wide range of biological systems, tissues, and functions. Longevity is an obvious marker of physiological aging. Simple model systems such as the single-cell budding yeast Saccharomyces cerevisiae (S. cerevisiae) and the nematode, Caenorhabditis elegans (C. elegans) are widely used to study the aging process and longevity. Here, we show that a polysaccharide fraction obtained from C. borivilianum increases the lifespan of S. cerevisiae and C. elegans, using an automated screening platform (ChronoscreenTM). Chemical analysis of this extract revealed a low molecular weight polysaccharide of 1000 Da, predominantly comprising Glu1→6Glu linkage. This polysaccharide showed significant dose-dependent extension of the median lifespan of S. cerevisiae by up to 41% and of the median lifespan of C. elegans by up to 10%. Taking cue from these results and the traditionally described benefits of Rasayanas on skin rejuvenation, we tested in vitro the polysaccharide for potential skin benefits. In a keratinocyte culture, we observed that this polysaccharide increased cell proliferation significantly, and induced synthesis of hyaluronic acid (HA), a well-known extracellular matrix component. Furthermore, when added to culture medium of human reconstructed epidermis, we observed an enhanced production of epidermal markers, e.g. CD44 and HA that are otherwise diminished in aged skin. Together, these results suggest that in

  19. Longevity effect of a polysaccharide from Chlorophytum borivilianum on Caenorhabditis elegans and Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Steve Thomas Pannakal

    Full Text Available The traditional Indian medicine, Ayurveda, provides insights and practical solutions towards a healthy life style. Rasayana is a branch of Ayurveda known for preserving and promoting health, enhancing the quality of life and delaying the aging process. In the traditional knowledge, the Rasayana herb, Chlorophytum borivilianum (C. borivilanum is regarded as a general health promoting tonic that delays aging and increases lifespan, cognitive function and physical strength. Aging is a complex and multifactorial physiological phenomenon that manifests itself over a wide range of biological systems, tissues, and functions. Longevity is an obvious marker of physiological aging. Simple model systems such as the single-cell budding yeast Saccharomyces cerevisiae (S. cerevisiae and the nematode, Caenorhabditis elegans (C. elegans are widely used to study the aging process and longevity. Here, we show that a polysaccharide fraction obtained from C. borivilianum increases the lifespan of S. cerevisiae and C. elegans, using an automated screening platform (ChronoscreenTM. Chemical analysis of this extract revealed a low molecular weight polysaccharide of 1000 Da, predominantly comprising Glu1→6Glu linkage. This polysaccharide showed significant dose-dependent extension of the median lifespan of S. cerevisiae by up to 41% and of the median lifespan of C. elegans by up to 10%. Taking cue from these results and the traditionally described benefits of Rasayanas on skin rejuvenation, we tested in vitro the polysaccharide for potential skin benefits. In a keratinocyte culture, we observed that this polysaccharide increased cell proliferation significantly, and induced synthesis of hyaluronic acid (HA, a well-known extracellular matrix component. Furthermore, when added to culture medium of human reconstructed epidermis, we observed an enhanced production of epidermal markers, e.g. CD44 and HA that are otherwise diminished in aged skin. Together, these results

  20. Longevity effect of a polysaccharide from Chlorophytum borivilianum on Caenorhabditis elegans and Saccharomyces cerevisiae.

    Science.gov (United States)

    Pannakal, Steve Thomas; Jäger, Sibylle; Duranton, Albert; Tewari, Amit; Saha, Subarna; Radhakrishnan, Aneesha; Roy, Nita; Kuntz, Jean François; Fermas, Soraya; James, Darryl; Mellor, Jane; Misra, Namita; Breton, Lionel

    2017-01-01

    The traditional Indian medicine, Ayurveda, provides insights and practical solutions towards a healthy life style. Rasayana is a branch of Ayurveda known for preserving and promoting health, enhancing the quality of life and delaying the aging process. In the traditional knowledge, the Rasayana herb, Chlorophytum borivilianum (C. borivilanum) is regarded as a general health promoting tonic that delays aging and increases lifespan, cognitive function and physical strength. Aging is a complex and multifactorial physiological phenomenon that manifests itself over a wide range of biological systems, tissues, and functions. Longevity is an obvious marker of physiological aging. Simple model systems such as the single-cell budding yeast Saccharomyces cerevisiae (S. cerevisiae) and the nematode, Caenorhabditis elegans (C. elegans) are widely used to study the aging process and longevity. Here, we show that a polysaccharide fraction obtained from C. borivilianum increases the lifespan of S. cerevisiae and C. elegans, using an automated screening platform (ChronoscreenTM). Chemical analysis of this extract revealed a low molecular weight polysaccharide of 1000 Da, predominantly comprising Glu1→6Glu linkage. This polysaccharide showed significant dose-dependent extension of the median lifespan of S. cerevisiae by up to 41% and of the median lifespan of C. elegans by up to 10%. Taking cue from these results and the traditionally described benefits of Rasayanas on skin rejuvenation, we tested in vitro the polysaccharide for potential skin benefits. In a keratinocyte culture, we observed that this polysaccharide increased cell proliferation significantly, and induced synthesis of hyaluronic acid (HA), a well-known extracellular matrix component. Furthermore, when added to culture medium of human reconstructed epidermis, we observed an enhanced production of epidermal markers, e.g. CD44 and HA that are otherwise diminished in aged skin. Together, these results suggest that in

  1. Insight into transcription factor gene duplication from Caenorhabditis elegans Promoterome-driven expression patterns

    Directory of Open Access Journals (Sweden)

    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.

  2. Impact of cigarette smoke exposure on innate immunity: a Caenorhabditis elegans model.

    Directory of Open Access Journals (Sweden)

    Rebecca M Green

    Full Text Available BACKGROUND: Cigarette smoking is the major cause of chronic obstructive pulmonary disease (COPD and lung cancer. Respiratory bacterial infections have been shown to be involved in the development of COPD along with impaired airway innate immunity. METHODOLOGY/PRINCIPAL FINDINGS: To address the in vivo impact of cigarette smoke (CS exclusively on host innate defense mechanisms, we took advantage of Caenorhabditis elegans (C. elegans, which has an innate immune system but lacks adaptive immune function. Pseudomonas aeruginosa (PA clearance from intestines of C. elegans was dampened by CS. Microarray analysis identified 6 candidate genes with a 2-fold or greater reduction after CS exposure, that have a human orthologue, and that may participate in innate immunity. To confirm a role of CS-down-regulated genes in the innate immune response to PA, RNA interference (RNAi by feeding was carried out in C. elegans to inhibit the gene of interest, followed by PA infection to determine if the gene affected innate immunity. Inhibition of lbp-7, which encodes a lipid binding protein, resulted in increased levels of intestinal PA. Primary human bronchial epithelial cells were shown to express mRNA of human Fatty Acid Binding Protein 5 (FABP-5, the human orthologue of lpb-7. Interestingly, FABP-5 mRNA levels from human smokers with COPD were significantly lower (p = 0.036 than those from smokers without COPD. Furthermore, FABP-5 mRNA levels were up-regulated (7-fold after bacterial (i.e., Mycoplasma pneumoniae infection in primary human bronchial epithelial cell culture (air-liquid interface culture. CONCLUSIONS: Our results suggest that the C. elegans model offers a novel in vivo approach to specifically study innate immune deficiencies resulting from exposure to cigarette smoke, and that results from the nematode may provide insight into human airway epithelial cell biology and cigarette smoke exposure.

  3. Impact of cigarette smoke exposure on innate immunity: a Caenorhabditis elegans model.

    Science.gov (United States)

    Green, Rebecca M; Gally, Fabienne; Keeney, Jonathon G; Alper, Scott; Gao, Bifeng; Han, Min; Martin, Richard J; Weinberger, Andrew R; Case, Stephanie R; Minor, Maisha N; Chu, Hong Wei

    2009-08-31

    Cigarette smoking is the major cause of chronic obstructive pulmonary disease (COPD) and lung cancer. Respiratory bacterial infections have been shown to be involved in the development of COPD along with impaired airway innate immunity. To address the in vivo impact of cigarette smoke (CS) exclusively on host innate defense mechanisms, we took advantage of Caenorhabditis elegans (C. elegans), which has an innate immune system but lacks adaptive immune function. Pseudomonas aeruginosa (PA) clearance from intestines of C. elegans was dampened by CS. Microarray analysis identified 6 candidate genes with a 2-fold or greater reduction after CS exposure, that have a human orthologue, and that may participate in innate immunity. To confirm a role of CS-down-regulated genes in the innate immune response to PA, RNA interference (RNAi) by feeding was carried out in C. elegans to inhibit the gene of interest, followed by PA infection to determine if the gene affected innate immunity. Inhibition of lbp-7, which encodes a lipid binding protein, resulted in increased levels of intestinal PA. Primary human bronchial epithelial cells were shown to express mRNA of human Fatty Acid Binding Protein 5 (FABP-5), the human orthologue of lpb-7. Interestingly, FABP-5 mRNA levels from human smokers with COPD were significantly lower (p = 0.036) than those from smokers without COPD. Furthermore, FABP-5 mRNA levels were up-regulated (7-fold) after bacterial (i.e., Mycoplasma pneumoniae) infection in primary human bronchial epithelial cell culture (air-liquid interface culture). Our results suggest that the C. elegans model offers a novel in vivo approach to specifically study innate immune deficiencies resulting from exposure to cigarette smoke, and that results from the nematode may provide insight into human airway epithelial cell biology and cigarette smoke exposure.

  4. New Haystacks Reveal New Needles: Using Caenorhabditis elegans to Identify Novel Targets for Ameliorating Body Composition Changes during Human Aging

    OpenAIRE

    Wolkow, Catherine A.

    2010-01-01

    Dramatic changes in body composition accompany aging in humans, particularly with respect to adiposity and the musculature. People accumulate fat as they age and lose muscle mass and strength. Caenorhabditis elegans nematodes are small, hermaphroditic soil nematodes that offer a flexible model for studying genetic pathways regulating body composition in humans. While there are significant physiological differences between worms and people, many of the genetic pathways relevant to human lipid ...

  5. Virulence variations in Shigella and enteroinvasive Escherichia coli using the Caenorhabditis elegans model.

    Science.gov (United States)

    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. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

    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 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. PMID:26848697

  7. Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans

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    Portal-Celhay Cynthia

    2012-03-01

    Full Text Available Abstract Background A powerful approach to understanding complex processes such as aging is to use model organisms amenable to genetic manipulation, and to seek relevant phenotypes to measure. Caenorhabditis elegans is particularly suited to studies of aging, since numerous single-gene mutations have been identified that affect its lifespan; it possesses an innate immune system employing evolutionarily conserved signaling pathways affecting longevity. As worms age, bacteria accumulate in the intestinal tract. However, quantitative relationships between worm genotype, lifespan, and intestinal lumen bacterial load have not been examined. We hypothesized that gut immunity is less efficient in older animals, leading to enhanced bacterial accumulation, reducing longevity. To address this question, we evaluated the ability of worms to control bacterial accumulation as a functional marker of intestinal immunity. Results We show that as adult worms age, several C. elegans genotypes show diminished capacity to control intestinal bacterial accumulation. We provide evidence that intestinal bacterial load, regulated by gut immunity, is an important causative factor of lifespan determination; the effects are specified by bacterial strain, worm genotype, and biologic age, all acting in concert. Conclusions In total, these studies focus attention on the worm intestine as a locus that influences longevity in the presence of an accumulating bacterial population. Further studies defining the interplay between bacterial species and host immunity in C. elegans may provide insights into the general mechanisms of aging and age-related diseases.

  8. Multi-environment model estimation for motility analysis of Caenorhabditis elegans.

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    Raphael Sznitman

    Full Text Available 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 used to accurately segment a target nematode. Our method is designed to simplify the burden often imposed on users; here, only a single image which includes a nematode in its environment must be provided for model learning. In addition, our platform enables the extraction of nematode 'skeletons' for straightforward motility quantification. We test our algorithm on various locomotive environments and compare performances with an intensity-based thresholding method. Overall, MEME outperforms the threshold-based approach for the overwhelming majority of cases examined. Ultimately, MEME provides researchers with an attractive platform for C. elegans' segmentation and 'skeletonizing' across a wide range of motility assays.

  9. The prevalence of Caenorhabditis elegans across 1.5 years in selected North German locations: the importance of substrate type, abiotic parameters, and Caenorhabditis competitors

    Science.gov (United States)

    2014-01-01

    Background Although the nematode Caenorhabditis elegans is a major model organism in diverse biological areas and well studied under laboratory conditions, little is known about its ecology. Therefore, characterization of the species’ natural habitats should provide a new perspective on its otherwise well-studied biology. The currently best characterized populations are in France, demonstrating that C. elegans prefers nutrient- and microorganism-rich substrates such as rotting fruits and decomposing plant matter. In order to extend these findings, we sampled C. elegans continuously across 1.5 years from rotting apples and compost heaps in three North German locations. Results C. elegans was found throughout summer and autumn in both years. It shares its habitat with the related nematode species C. remanei, which could thus represent an important competitor for a similar ecological niche. The two species were isolated from the same site, but rarely the same substrate sample. In fact, C. elegans was mainly found on compost and C. remanei on rotten apples, possibly suggesting niche separation. The occurrence of C. elegans itself was related to environmental humidity and rain, although the correlation was significant for only one sampling site each. Additional associations between nematode prevalence and abiotic parameters could not be established. Conclusions Taken together, our findings vary from the previous results for French C. elegans populations in that the considered German populations always coexisted with the congeneric species C. remanei (rather than C. briggsae as in France) and that C. elegans prevalence can associate with humidity and rain (rather than temperature, as suggested for French populations). Consideration of additional locations and time points is thus essential for full appreciation of the nematode's natural ecology. PMID:24502455

  10. 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...... homologues of Niemann-Pick C disease proteins. Our approach is generally useful for identifying fluorescent probes in the presence of high cellular autofluorescence....

  11. A conserved checkpoint monitors meiotic chromosome synapsis inCaenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria.

    Science.gov (United States)

    Portal-Celhay, Cynthia; Nehrke, Keith; Blaser, Martin J

    2013-02-01

    Horizontal gene transfer (HGT) between bacteria occurs in the intestinal tract of their animal hosts and facilitates both virulence and antibiotic resistance. A model in which both the pathogen and the host are genetically tractable facilitates developing insight into mechanistic processes enabling or restricting the transfer of antibiotic resistance genes. Here we develop an in vivo experimental system to study HGT in bacteria using Caenorhabditis elegans as a model host. Using a thermosensitive conjugative system, we provide evidence that conjugation between two Escherichia coli strains can take place in the intestinal lumen of N2 wild-type worms at a rate of 10(-3) and 10(-2) per donor. We also show that C. elegans age and genotype are important determinants of the frequency of conjugation. Whereas ∼1 transconjugant for every 100 donor cells could be recovered from the intestine of N2 C. elegans, for the age-1 and tol-1 mutants, the detected rate of transconjugation (10(-3) and 10(-4) per donor cell, respectively) was significantly lower. This work demonstrates that increased recombination among lumenal microbial populations is a phenotype associated with host aging, and the model provides a framework to study the dynamics of bacterial horizontal gene transfer within the intestinal environment.

  13. Novel and conserved protein macoilin is required for diverse neuronal functions in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Akiko Miyara

    2011-05-01

    Full Text Available Neural signals are processed in nervous systems of animals responding to variable environmental stimuli. This study shows that a novel and highly conserved protein, macoilin (MACO-1, plays an essential role in diverse neural functions in Caenorhabditis elegans. maco-1 mutants showed abnormal behaviors, including defective locomotion, thermotaxis, and chemotaxis. Expression of human macoilin in the C. elegans nervous system weakly rescued the abnormal thermotactic phenotype of the maco-1 mutants, suggesting that macoilin is functionally conserved across species. Abnormal thermotaxis may have been caused by impaired locomotion of maco-1 mutants. However, calcium imaging of AFD thermosensory neurons and AIY postsynaptic interneurons of maco-1 mutants suggest that macoilin is required for appropriate responses of AFD and AIY neurons to thermal stimuli. Studies on localization of MACO-1 showed that C. elegans and human macoilins are localized mainly to the rough endoplasmic reticulum. Our results suggest that macoilin is required for various neural events, such as the regulation of neuronal activity.

  14. Identification of vacuoles containing extraintestinal differentiated forms of Legionella pneumophila in colonized Caenorhabditis elegans soil nematodes

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    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

    2015-01-01

    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. PMID:26131925

  15. Neural Circuitry That Mediates Behavior Governing the Tradeoffs Between Survival and Reproduction in Caenorhabditis elegans.

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    Emmons, Scott W

    2017-12-01

    In all outcrossing sexual species there is a mechanism that brings two parents together. For animals, this reproductive requirement may at times conflict with other needs, such as foraging for food. This tension has been studied using the tiny (1 mm) nematode worm, Caenorhabditis elegans. In a trade off between certainty of survival and possibility of reproduction, the C. elegans male will abandon a food patch lacking mates and explore its environment to find one where mates are present. A quantitative behavioral assay has been used to study the behavioral mechanism of mate searching and nutritional, sexual, and neurohormonal pathways that influence the underlying drive state. Taking advantage of the known connectivity of the C. elegans nervous system, neural pathways have been identified that influence the male's behavior in the presence of food with and without mates. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

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

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    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

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

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    Sandeep Kumar

    2016-02-01

    Full Text Available 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

  18. Regulatory elements of Caenorhabditis elegans ribosomal protein genes

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    Sleumer Monica C

    2012-08-01

    Full Text Available Abstract Background Ribosomal protein genes (RPGs are essential, tightly regulated, and highly expressed during embryonic development and cell growth. Even though their protein sequences are strongly conserved, their mechanism of regulation is not conserved across yeast, Drosophila, and vertebrates. A recent investigation of genomic sequences conserved across both nematode species and associated with different gene groups indicated the existence of several elements in the upstream regions of C. elegans RPGs, providing a new insight regarding the regulation of these genes in C. elegans. Results In this study, we performed an in-depth examination of C. elegans RPG regulation and found nine highly conserved motifs in the upstream regions of C. elegans RPGs using the motif discovery algorithm DME. Four motifs were partially similar to transcription factor binding sites from C. elegans, Drosophila, yeast, and human. One pair of these motifs was found to co-occur in the upstream regions of 250 transcripts including 22 RPGs. The distance between the two motifs displayed a complex frequency pattern that was related to their relative orientation. We tested the impact of three of these motifs on the expression of rpl-2 using a series of reporter gene constructs and showed that all three motifs are necessary to maintain the high natural expression level of this gene. One of the motifs was similar to the binding site of an orthologue of POP-1, and we showed that RNAi knockdown of pop-1 impacts the expression of rpl-2. We further determined the transcription start site of rpl-2 by 5’ RACE and found that the motifs lie 40–90 bases upstream of the start site. We also found evidence that a noncoding RNA, contained within the outron of rpl-2, is co-transcribed with rpl-2 and cleaved during trans-splicing. Conclusions Our results indicate that C. elegans RPGs are regulated by a complex novel series of regulatory elements that is evolutionarily distinct from

  19. Linking Subcellular Disturbance to Physiological Behavior and Toxicity Induced by Quantum Dots in Caenorhabditis elegans.

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    Wang, Qin; Zhou, Yanfeng; Song, Bin; Zhong, Yiling; Wu, Sicong; Cui, Rongrong; Cong, Haixia; Su, Yuanyuan; Zhang, Huimin; He, Yao

    2016-06-01

    The wide-ranging applications of fluorescent semiconductor quantum dots (QDs) have triggered increasing concerns about their biosafety. Most QD-related toxicity studies focus on the subcellular processes in cultured cells or global physiological effects on whole animals. However, it is unclear how QDs affect subcellular processes in living organisms, or how the subcellular disturbance contributes to the overall toxicity. Here the behavior and toxicity of QDs of three different sizes in Caenorhabditis elegans (C. elegans) are systematically investigated at both the systemic and the subcellular level. Specifically, clear size-dependent distribution and toxicity of the QDs in the digestive tract are observed. Short-term exposure of QDs leads to acute toxicity on C. elegans, yet incurring no lasting, irreversible damage. In contrast, chronic exposure of QDs severely inhibits development and shortens lifespan. Subcellular analysis reveals that endocytosis and nutrition storage are disrupted by QDs, which likely accounts for the severe deterioration in growth and longevity. This work reveals that QDs invasion disrupts key subcellular processes in living organisms, and may cause permanent damage to the tissues and organs over long-term retention. The findings provide invaluable information for safety evaluations of QD-based applications and offer new opportunities for design of novel nontoxic nanoprobes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Spermatogenesis-specific features of the meiotic program in Caenorhabditis elegans.

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    Diane C Shakes

    2009-08-01

    Full Text Available In most sexually reproducing organisms, the fundamental process of meiosis is implemented concurrently with two differentiation programs that occur at different rates and generate distinct cell types, sperm and oocytes. However, little is known about how the meiotic program is influenced by such contrasting developmental programs. Here we present a detailed timeline of late meiotic prophase during spermatogenesis in Caenorhabditis elegans using cytological and molecular landmarks to interrelate changes in chromosome dynamics with germ cell cellularization, spindle formation, and cell cycle transitions. This analysis expands our understanding C. elegans spermatogenesis, as it identifies multiple spermatogenesis-specific features of the meiotic program and provides a framework for comparative studies. Post-pachytene chromatin of spermatocytes is distinct from that of oocytes in both composition and morphology. Strikingly, C. elegans spermatogenesis includes a previously undescribed karyosome stage, a common but poorly understood feature of meiosis in many organisms. We find that karyosome formation, in which chromosomes form a constricted mass within an intact nuclear envelope, follows desynapsis, involves a global down-regulation of transcription, and may support the sequential activation of multiple kinases that prepare spermatocytes for meiotic divisions. In spermatocytes, the presence of centrioles alters both the relative timing of meiotic spindle assembly and its ultimate structure. These microtubule differences are accompanied by differences in kinetochores, which connect microtubules to chromosomes. The sperm-specific features of meiosis revealed here illuminate how the underlying molecular machinery required for meiosis is differentially regulated in each sex.

  1. Pseudomonas aeruginosa disrupts Caenorhabditis elegans iron homeostasis, causing a hypoxic response and death.

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    Kirienko, Natalia V; Kirienko, Daniel R; Larkins-Ford, Jonah; Wählby, Carolina; Ruvkun, Gary; Ausubel, Frederick M

    2013-04-17

    The opportunistic pathogen Pseudomonas aeruginosa causes serious human infections, but effective treatments and the mechanisms mediating pathogenesis remain elusive. Caenorhabditis elegans shares innate immune pathways with humans, making it invaluable to investigate infection. To determine how P. aeruginosa disrupts host biology, we studied how P. aeruginosa kills C. elegans in a liquid-based pathogenesis model. We found that P. aeruginosa-mediated killing does not require quorum-sensing pathways or host colonization. A chemical genetic screen revealed that iron chelators alleviate P. aeruginosa-mediated killing. Consistent with a role for iron in P. aeruginosa pathogenesis, the bacterial siderophore pyoverdin was required for virulence and was sufficient to induce a hypoxic response and death in the absence of bacteria. Loss of the C. elegans hypoxia-inducing factor HIF-1, which regulates iron homeostasis, exacerbated P. aeruginosa pathogenesis, further linking hypoxia and killing. As pyoverdin is indispensable for virulence in mice, pyoverdin-mediated hypoxia is likely to be relevant in human pathogenesis. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Residual ground-water levels of the neonicotinoid thiacloprid perturb chemosensing of Caenorhabditis elegans.

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    Hopewell, Hannah; Floyd, Kieran G; Burnell, Daniel; Hancock, John T; Allainguillaume, Joel; Ladomery, Michael R; Wilson, Ian D

    2017-09-01

    This study investigated the neurological effects of residual ground-water levels of thiacloprid on the non-target organism Caenorhabditis elegans. Nematodes treated with thiacloprid showed a dose-dependent and significantly increased twitch response at concentrations above 50 ng mL -1 that disabled their forward locomotion in liquid culture. In comparison with untreated controls, 10 ng mL -1 thiacloprid perturbed the chemosensory ability of C. elegans such that the nematodes no longer demonstrated positive chemotaxis towards a NaCl chemo-attractant, reducing their chemotaxis index from +0.48 to near to zero. Nematodes also exhibited a locomotion characteristic of those devoid of chemo-attraction, making significantly more pirouetting turns of ≥90° than the untreated controls. Compared to the untreated controls, expression of the endocytosis-associated gene, Rab-10, was also increased in C. elegans that had developed to adulthood in the presence of 10 ng mL -1 thiacloprid, suggesting their active engagement in increased recycling of affected cellular components, such as their nAChRs. Thus, even residual, low levels of this less potent neonicotinoid that may be found in field ground-water had measurable effects on a beneficial soil organism which may have environmental and ecological implications that are currently poorly understood.

  3. Aversive olfactory learning and associative long-term memory in Caenorhabditis elegans.

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    Amano, Hisayuki; Maruyama, Ichiro N

    2011-10-01

    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 4.0), as an unconditioned stimulus (US). Before the conditioning, worms were attracted to 1-propanol and avoided HCl in chemotaxis assay. In contrast, after massed or spaced training, worms were either not attracted at all to or repelled from 1-propanol on the assay plate. The memory after the spaced training was retained for 24 h, while the memory after the massed training was no longer observable within 3 h. Worms pretreated with transcription and translation inhibitors failed to form the memory by the spaced training, whereas the memory after the massed training was not significantly affected by the inhibitors and was sensitive to cold-shock anesthesia. Therefore, the memories after the spaced and massed trainings can be classified as long-term memory (LTM) and short-term/middle-term memory (STM/MTM), respectively. Consistently, like other organisms including Aplysia, Drosophila, and mice, C. elegans mutants defective in nmr-1 encoding an NMDA receptor subunit failed to form both LTM and STM/MTM, while mutations in crh-1 encoding the CREB transcription factor affected only the LTM.

  4. Biosafety assessment of Gd@C82(OH)22 nanoparticles on Caenorhabditis elegans

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    Zhang, Wendi; Sun, Baoyun; Zhang, Longze; Zhao, Baolu; Nie, Guangjun; Zhao, Yuliang

    2011-06-01

    Gd@C82(OH)22, a water-soluble endohedral metallofullerene derivative, has been proven to possess significant antineoplastic activity in mice. Toxicity studies of the nanoparticle have shown some evidence of low or non toxicity in mice and cell models. Here we employed Caenorhabditis elegans (C. elegans) as a model organism to further evaluate the short- and long-term toxicity of Gd@C82(OH)22 and possible behavior changes under normal and stress culture conditions. With treatment of Gd@C82(OH)22 at 0.01, 0.1, 1.0 and 10 μg ml-1 within one generation (short-term), C. elegans showed no significant decrease in longevity or thermotolerance compared to the controls. Furthermore, when Gd@C82(OH)22 treatment was extended up to six generations (long-term), non-toxic effects to the nematodes were found. In addition, data from body length measurement, feeding rate and egg-laying assays with short-term treatment demonstrated that the nanoparticles have no significant impact on the individual growth, feeding behavior and reproductive ability, respectively. In summary, this work has shown that Gd@C82(OH)22 is tolerated well by worms and it has no apparent toxic effects on longevity, stress resistance, growth and behaviors that were observed in both adult and young worms. Our work lays the foundations for further developments of this anti-neoplastic agent for clinical applications.

  5. Cyanobacterial Xenobiotics as Evaluated by a Caenorhabditis elegans Neurotoxicity Screening Test

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    Jingjuan Ju

    2014-04-01

    Full Text Available In fresh waters cyanobacterial blooms can produce a variety of toxins, such as microcystin variants (MCs and anatoxin-a (ANA. ANA is a well-known neurotoxin, whereas MCs are hepatotoxic and, to a lesser degree, also neurotoxic. Neurotoxicity applies especially to invertebrates lacking livers. Current standardized neurotoxicity screening methods use rats or mice. However, in order to minimize vertebrate animal experiments as well as experimental time and effort, many investigators have proposed the nematode Caenorhabditis elegans as an appropriate invertebrate model. Therefore, four known neurotoxic compounds (positive compounds: chlorpyrifos, abamectin, atropine, and acrylamide were chosen to verify the expected impacts on autonomic (locomotion, feeding, defecation and sensory (thermal, chemical, and mechanical sensory perception functions in C. elegans. This study is another step towards successfully establishing C. elegans as an alternative neurotoxicity model. By using this protocol, anatoxin-a adversely affected locomotive behavior and pharyngeal pumping frequency and, most strongly, chemotactic and thermotactic behavior, whereas MC-LR impacted locomotion, pumping, and mechanical behavior, but not chemical sensory behavior. Environmental samples can also be screened in this simple and fast way for neurotoxic characteristics. The filtrate of a Microcystis aeruginosa culture, known for its hepatotoxicity, also displayed mild neurotoxicity (modulated short-term thermotaxis. These results show the suitability of this assay for environmental cyanotoxin-containing samples.

  6. Tenebrio molitor Extracts Modulate the Response to Environmental Stressors and Extend Lifespan in Caenorhabditis elegans.

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    Won, Seong-Min; Cha, Hye-Uk; Yi, Sun Shin; Kim, Sung-Jo; Park, Sang-Kyu

    2016-09-08

    Tenebrio molitor are large insects and their larvae are consumed as food in many countries. The nutritional composition of T. molitor has been studied and contains high amounts of proteins, unsaturated fatty acids, and valuable minerals. However, the bioactivity of T. molitor has not been fully understood. We examined the effects of T. molitor extracts on resistance to oxidative stress and organism's lifespan using Caenorhabditis elegans as a model system. The response to heat shock and ultraviolet (UV) irradiation was monitored in vivo. The extracts from T. molitor showed significant effects on resistance to oxidative stress and UV irradiation and extend both mean and maximum lifespan of C. elegans. The number of progeny produced significantly increased in animals supplemented with T. molitor extracts. In addition, the expression of hsp-16.2 and sod-3 was markedly upregulated by supplementation with T. molitor extracts. These findings suggest that T. molitor extracts can increase response to stressors and extend lifespan by the induction of longevity assurance genes in C. elegans.

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

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    Puckett Robinson, Carmie; Schwarz, Erich M; Sternberg, Paul W

    2013-01-01

    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. 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. 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-species phylogenetic comparisons.

  8. MicroRNA predictors of longevity in Caenorhabditis elegans.

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    Zachary Pincus

    2011-09-01

    Full Text Available Neither genetic nor environmental factors fully account for variability in individual longevity: genetically identical invertebrates in homogenous environments often experience no less variability in lifespan than outbred human populations. Such variability is often assumed to result from stochasticity in damage accumulation over time; however, the identification of early-life gene expression states that predict future longevity would suggest that lifespan is least in part epigenetically determined. Such "biomarkers of aging," genetic or otherwise, nevertheless remain rare. In this work, we sought early-life differences in organismal robustness in unperturbed individuals and examined the utility of microRNAs, known regulators of lifespan, development, and robustness, as aging biomarkers. We quantitatively examined Caenorhabditis elegans reared individually in a novel apparatus and observed throughout their lives. Early-to-mid-adulthood measures of homeostatic ability jointly predict 62% of longevity variability. Though correlated, markers of growth/muscle maintenance and of metabolic by-products ("age pigments" report independently on lifespan, suggesting that graceful aging is not a single process. We further identified three microRNAs in which early-adulthood expression patterns individually predict up to 47% of lifespan differences. Though expression of each increases throughout this time, mir-71 and mir-246 correlate with lifespan, while mir-239 anti-correlates. Two of these three microRNA "biomarkers of aging" act upstream in insulin/IGF-1-like signaling (IIS and other known longevity pathways, thus we infer that these microRNAs not only report on but also likely determine longevity. Thus, fluctuations in early-life IIS, due to variation in these microRNAs and from other causes, may determine individual lifespan.

  9. 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.

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

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    Windy A Boyd

    2009-09-01

    Full Text Available 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.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.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 affects C. elegans development in a concentration dependent

  11. Application of a Mathematical Model to Describe the Effects of Chlorpyrifos on Caenorhabditis elegans Development

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    Boyd, Windy A.; Smith, Marjolein V.; Kissling, Grace E.; Rice, Julie R.; Snyder, Daniel W.; Portier, Christopher J.; Freedman, Jonathan H.

    2009-01-01

    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 µM) 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 affects C

  12. Evolution of host innate defence: insights from Caenorhabditis elegans and primitive invertebrates.

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    Irazoqui, Javier E; Urbach, Jonathan M; Ausubel, Frederick M

    2010-01-01

    The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in identifying the host response pathways that are involved in its defence against infection. Strikingly, C. elegans seems to detect, and respond to, infection without the involvement of its homologue of Toll-like receptors, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans and what can they tell us about innate immunity in higher organisms?

  13. A review of transgenerational epigenetics for RNAi, longevity, germline maintenance and olfactory imprinting in Caenorhabditis elegans.

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    Rankin, Catharine H

    2015-01-01

    Inheritance of acquired characteristics without changes in DNA sequence has been called transgenerational epigenetics. This review looks at studies that used the model system Caenorhabditis elegans to uncover mechanisms of transgenerational epigenetics in studies of RNA interference, studies of longevity, studies of germline continuity and a study on olfactory imprinting. In each case, researchers have uncovered critical roles for small RNAs and for Argonaute proteins. They have revealed several different genetic pathways that mediate RNA silencing of foreign RNA for a few or for many generations, as well as identifying a related pathway responsible for recognized self-generated RNAs. Together, these studies have greatly advanced our understanding of trangenerational epigenetics. © 2015. Published by The Company of Biologists Ltd.

  14. Arsenite exposure accelerates aging process regulated by the transcription factor DAF-16/FOXO in Caenorhabditis elegans.

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    Yu, Chan-Wei; How, Chun Ming; Liao, Vivian Hsiu-Chuan

    2016-05-01

    Arsenic is a known human carcinogen and high levels of arsenic contamination in food, soils, water, and air are of toxicology concerns. Nowadays, arsenic is still a contaminant of emerging interest, yet the effects of arsenic on aging process have received little attention. In this study, we investigated the effects and the underlying mechanisms of chronic arsenite exposure on the aging process in Caenorhabditis elegans. The results showed that prolonged arsenite exposure caused significantly decreased lifespan compared to non-exposed ones. In addition, arsenite exposure (100 μM) caused significant changes of age-dependent biomarkers, including a decrease of defecation frequency, accumulations of intestinal lipofuscin and lipid peroxidation in an age-dependent manner in C. elegans. Further evidence revealed that intracellular reactive oxygen species (ROS) level was significantly increased in an age-dependent manner upon 100 μM arsenite exposure. Moreover, the mRNA levels of transcriptional makers of aging (hsp-16.1, hsp-16.49, and hsp-70) were increased in aged worms under arsenite exposure (100 μM). Finally, we showed that daf-16 mutant worms were more sensitive to arsenite exposure (100 μM) on lifespan and failed to induce the expression of its target gene sod-3 in aged daf-16 mutant under arsenite exposure (100 μM). Our study demonstrated that chronic arsenite exposure resulted in accelerated aging process in C. elegans. The overproduction of intracellular ROS and the transcription factor DAF-16/FOXO play roles in mediating the accelerated aging process by arsenite exposure in C. elegans. This study implicates a potential ecotoxicological and health risk of arsenic in the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Regulation of Intraflagellar Transport in the sensory cilia of Caenorhabditis Elegans

    NARCIS (Netherlands)

    J.A. Burghoorn (Jan)

    2006-01-01

    textabstractCilia zijn kleine uitstulpingen op het celoppervlakte. Ze zijn belangrijk bij de beweging van cellen, zoals bijvoorbeeld bij sperma cellen, maar hebben daarnaast ook een sensorische functie. Wij hebben voor ons cilia onderzoek gekozen voor het model organisme Caenorhabditis elegans,

  18. Characterization of the Caenorhabditis elegans Tc1 transposase in vivo and in vitro

    NARCIS (Netherlands)

    Vos, J C; van Luenen, H.G.A.M.; Plasterk, R.H.A.

    We have investigated the function of the Tc1A gene of the mobile element Tc1 of Caenorhabditis elegans. Tc1 is a member of a family of transposons found in several animal phyla, such as nematodes, insects, and vertebrates. Two lines of evidence show that Tc1A encodes the transposase of Tc1. First,

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

    Science.gov (United States)

    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...

  20. Specific RNA Interference in Caenorhabditis elegans by Ingested dsRNA Expressed in Bacillus subtilis

    NARCIS (Netherlands)

    Lezzerini, M.; van de Ven, K.; Veerman, M.; Brul, S.; Budovskaya, Y.V.

    2015-01-01

    In nematodes, genome-wide RNAi-screening has been widely used as a rapid and efficient method to identify genes involved in the aging processes. By far the easiest way of inducing RNA interference (RNAi) in Caenorhabditis elegans is by feeding Escherichia coli that expresses specific double stranded

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    In many organisms, population density sensing and sexual attraction rely on small molecule-based signaling systems. In the nematode Caenorhabditis elegans, population density is monitored via specific glycosides of the dideoxysugar ascarylose that promote entry into an alternate larval stage, the no...

  3. Biological activity of Bacillus thuringiensis (Bacillales: Bacillaceae) chitinase against Caenorhabditis elegans (Rhabditida: Rhabditidae)

    Czech Academy of Sciences Publication Activity Database

    Zhang, L.; Yu, J.; Xie, Y.; Lin, H.; Huang, Z.; Xu, L.; Gelbič, Ivan; Guan, X.

    2014-01-01

    Roč. 107, č. 2 (2014), s. 551-558 ISSN 0022-0493 Institutional support: RVO:60077344 Keywords : Bacillus thuringiensis * Caenorhabditis elegans * chitinase Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 1.506, year: 2014 http://www.bioone.org/doi/pdf/10.1603/EC13201

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

    Science.gov (United States)

    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…

  5. Specific microRNAs Regulate Heat Stress Responses in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Nehammer, Camilla; Podolska, Agnieszka; Mackowiak, Sebastian D

    2015-01-01

    to heat stress in Caenorhabditis elegans and show that a discrete subset of miRNAs is thermoregulated. Using in-depth phenotypic analyses of miRNA deletion mutant strains we reveal multiple developmental and post-developmental survival and behavioral functions for specific miRNAs during heat stress. We...

  6. DHS-21, a dicarbonyl/L-xylulose reductase (DCXR) ortholog, regulates longevity and reproduction in Caenorhabditis elegans.

    Science.gov (United States)

    Son, Le Tho; Ko, Kyung-Min; Cho, Jeong Hoon; Singaravelu, Gunasekaran; Chatterjee, Indrani; Choi, Tae-Woo; Song, Hyun-Ok; Yu, Jae-Ran; Park, Byung-Jae; Lee, Sun-Kyung; Ahnn, Joohong

    2011-05-06

    Dicarbonyl/L-xylulose reductase (DCXR) converts l-xylulose into xylitol, and reduces various α-dicarbonyl compounds, thus performing a dual role in carbohydrate metabolism and detoxification. In this study, we identified DHS-21 as the only DCXR ortholog in Caenorhabditis elegans. The dhs-21 gene is expressed in various tissues including the intestine, gonadal sheath cells, uterine seam (utse) cells, the spermathecal-uterus (sp-ut) valve and on the plasma membrane of spermatids. Recombinant DHS-21 was shown to convert L-xylulose to xylitol using NADPH as a cofactor. Dhs-21 null mutants of C. elegans show defects in longevity, reproduction and egg-laying. Knock-down of daf-16 and elt-2 transcription factors affected dhs-21 expression. These results suggest that DHS-21 is a bona fide DCXR of C. elegans, essential for normal life span and reproduction. Copyright © 2011. Published by Elsevier B.V.

  7. 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

    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......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...... stages (L1 to L4), dauer and L1/L4 post dauer. Histones were analyzed by our optimized middle-down protein sequencing platform using high mass accuracy tandem mass spectrometry. This allows quantification of intact histone tails and detailed characterization of distinct histone tails carrying co...

  8. Statins inhibit protein lipidation and induce the unfolded protein response in the non-sterol producing nematode Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Mörck, Catarina; Olsen, Louise Cathrine Braun; Kurth, Caroline

    2009-01-01

    of lipid moieties for protein prenylation. The nematode Caenorhabditis elegans possesses a mevalonate pathway that lacks the branch leading to cholesterol synthesis, and thus represents an ideal organism to specifically study the noncholesterol roles of the pathway. Inhibiting HMG-CoA reductase in C....... elegans using statins or RNAi leads to developmental arrest and loss of membrane association of a GFP-based prenylation reporter. The unfolded protein response (UPR) is also strongly activated, suggesting that impaired prenylation of small GTPases leads to the accumulation of unfolded proteins and ER....... elegans. These results provide a mechanism for the pleiotropic effects of statins and suggest that statins could be used clinically where UPR activation may be of therapeutic benefit....

  9. A rolling circle replication mechanism produces multimeric lariats of mitochondrial DNA in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Samantha C Lewis

    2015-02-01

    Full Text Available Mitochondrial DNA (mtDNA encodes respiratory complex subunits essential to almost all eukaryotes; hence respiratory competence requires faithful duplication of this molecule. However, the mechanism(s of its synthesis remain hotly debated. Here we have developed Caenorhabditis elegans as a convenient animal model for the study of metazoan mtDNA synthesis. We demonstrate that C. elegans mtDNA replicates exclusively by a phage-like mechanism, in which multimeric molecules are synthesized from a circular template. In contrast to previous mammalian studies, we found that mtDNA synthesis in the C. elegans gonad produces branched-circular lariat structures with multimeric DNA tails; we were able to detect multimers up to four mtDNA genome unit lengths. Further, we did not detect elongation from a displacement-loop or analogue of 7S DNA, suggesting a clear difference from human mtDNA in regard to the site(s of replication initiation. We also identified cruciform mtDNA species that are sensitive to cleavage by the resolvase RusA; we suggest these four-way junctions may have a role in concatemer-to-monomer resolution. Overall these results indicate that mtDNA synthesis in C. elegans does not conform to any previously documented metazoan mtDNA replication mechanism, but instead are strongly suggestive of rolling circle replication, as employed by bacteriophages. As several components of the metazoan mitochondrial DNA replisome are likely phage-derived, these findings raise the possibility that the rolling circle mtDNA replication mechanism may be ancestral among metazoans.

  10. Bacillus licheniformis Isolated from Traditional Korean Food Resources Enhances the Longevity of Caenorhabditis elegans through Serotonin Signaling.

    Science.gov (United States)

    Park, Mi Ri; Oh, Sangnam; Son, Seok Jun; Park, Dong-June; Oh, Sejong; Kim, Sae Hun; Jeong, Do-Youn; Oh, Nam Su; Lee, Youngbok; Song, Minho; Kim, Younghoon

    2015-12-02

    In this study, we investigated potentially probiotic Bacillus licheniformis strains isolated from traditional Korean food sources for ability to enhance longevity using the nematode Caenorhabditis elegans as a simple in vivo animal model. We first investigated whether B. licheniformis strains were capable of modulating the lifespan of C. elegans. Among the tested strains, preconditioning with four B. licheniformis strains significantly enhanced the longevity of C. elegans. Unexpectedly, plate counting and transmission electron microscopy (TEM) results indicated that B. licheniformis strains were not more highly attached to the C. elegans intestine compared with Escherichia coli OP50 or Lactobacillus rhamnosus GG controls. In addition, qRT-PCR and an aging assay with mutant worms showed that the conditioning of B. licheniformis strain 141 directly influenced genes associated with serotonin signaling in nematodes, including tph-1 (tryptophan hydroxylase), bas-1 (serotonin- and dopamine-synthetic aromatic amino acid decarboxylase), mod-1 (serotonin-gated chloride channel), ser-1, and ser-7 (serotonin receptors) during C. elegans aging. Our findings suggest that B. licheniformis strain 141, which is isolated from traditional Korean foods, is a probiotic generally recognized as safe (GRAS) strain that enhances the lifespan of C. elegans via host serotonin signaling.

  11. The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety

    DEFF Research Database (Denmark)

    Juozaityte, Vaida; Pladevall-Morera, David; Podolska, Agnieszka

    2017-01-01

    -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......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......-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....

  12. Deep Conservation of Genes Required for Both Drosophila melanogaster and Caenorhabditis elegans Sleep Includes a Role for Dopaminergic Signaling

    Science.gov (United States)

    Singh, Komudi; Ju, Jennifer Y.; Walsh, Melissa B.; DiIorio, Michael A.; Hart, Anne C.

    2014-01-01

    Objectives: Cross-species conservation of sleep-like behaviors predicts the presence of conserved molecular mechanisms underlying sleep. However, limited experimental evidence of conservation exists. Here, this prediction is tested directly. Measurements and Results: During lethargus, Caenorhabditis elegans spontaneously sleep in short bouts that are interspersed with bouts of spontaneous locomotion. We identified 26 genes required for Drosophila melanogaster sleep. Twenty orthologous C. elegans genes were selected based on similarity. Their effect on C. elegans sleep and arousal during the last larval lethargus was assessed. The 20 most similar genes altered both the quantity of sleep and arousal thresholds. In 18 cases, the direction of change was concordant with Drosophila studies published previously. Additionally, we delineated a conserved genetic pathway by which dopamine regulates sleep and arousal. In C. elegans neurons, G-alpha S, adenylyl cyclase, and protein kinase A act downstream of D1 dopamine receptors to regulate these behaviors. Finally, a quantitative analysis of genes examined herein revealed that C. elegans arousal thresholds were directly correlated with amount of sleep during lethargus. However, bout duration varies little and was not correlated with arousal thresholds. Conclusions: The comprehensive analysis presented here suggests that conserved genes and pathways are required for sleep in invertebrates and, likely, across the entire animal kingdom. The genetic pathway delineated in this study implicates G-alpha S and previously known genes downstream of dopamine signaling in sleep. Quantitative analysis of various components of quiescence suggests that interdependent or identical cellular and molecular mechanisms are likely to regulate both arousal and sleep entry. Citation: Singh K, Ju JY, Walsh MB, Dilorio MA, Hart AC. Deep conservation of genes required for both Drosophila melanogaster and Caenorhabditis elegans sleep includes a role for

  13. Microfluidic devices for analysis of spatial orientation behaviors in semi-restrained Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Kathryn E McCormick

    Full Text Available This article describes the fabrication and use of microfluidic devices for investigating spatial orientation behaviors in nematode worms (Caenorhabditis elegans. Until now, spatial orientation has been studied in freely moving nematodes in which the frequency and nature of encounters with the gradient are uncontrolled experimental variables. In the new devices, the nematode is held in place by a restraint that aligns the longitudinal axis of the body with the border between two laminar fluid streams, leaving the animal's head and tail free to move. The content of the fluid streams can be manipulated to deliver step gradients in space or time. We demonstrate the utility of the device by identifying previously uncharacterized aspects of the behavioral mechanisms underlying chemotaxis, osmotic avoidance, and thermotaxis in this organism. The new devices are readily adaptable to behavioral and imaging studies involving fluid borne stimuli in a wide range of sensory modalities.

  14. Immune defense mechanisms in the Caenorhabditis elegans intestinal epithelium.

    Science.gov (United States)

    Pukkila-Worley, Read; Ausubel, Frederick M

    2012-02-01

    Intestinal epithelial cells provide an essential line of defense for Caernohabditis elegans against ingested pathogens. Because nematodes consume microorganisms as their food source, there has presumably been selection pressure to evolve and maintain immune defense mechanisms within the intestinal epithelium. Here we review recent advances that further define the immune signaling network within these cells and suggest mechanisms used by the nematode to monitor for infection. In reviewing studies of pathogenesis that use this simple model system, we hope to illustrate some of the basic principles of epithelial immunity that may also be of relevance in higher order hosts. Copyright © 2012. Published by Elsevier Ltd.

  15. Genetics, life span, health span, and the aging process in Caenorhabditis elegans.

    Science.gov (United States)

    Tissenbaum, Heidi A

    2012-05-01

    As a tool for measuring the aging process, life span has been invaluable in dissecting the genes that modulate longevity. Studies over the past few decades have identified several hundred genes that can modify life span in model organisms such as yeast, worms, and flies. Yet, despite this vast amount of research, we still do not fully understand how the genes that affect life span influence how an organism ages. How does modulation of the genes that affect life span contribute to the aging process? Does life-span extension result in extension of healthy aging? Here, we will focus primarily on the insulin/IGF-1 signaling pathway in Caenorhabditis elegans because members of this pathway have been shown to be associated with extended life span across phylogeny, from worms to humans. I discuss how this connects to the aging process, age-associated disease, and the potential to increase healthy aging in addition to lengthening life span.

  16. Lysosome biogenesis mediated by vps-18 affects apoptotic cell degradation in Caenorhabditis elegans.

    Science.gov (United States)

    Xiao, Hui; Chen, Didi; Fang, Zhou; Xu, Jing; Sun, Xiaojuan; Song, Song; Liu, Jiajia; Yang, Chonglin

    2009-01-01

    Appropriate clearance of apoptotic cells (cell corpses) is an important step of programmed cell death. Although genetic and biochemical studies have identified several genes that regulate the engulfment of cell corpses, how these are degraded after being internalized in engulfing cell remains elusive. Here, we show that VPS-18, the Caenorhabditis elegans homologue of yeast Vps18p, is critical to cell corpse degradation. VPS-18 is expressed and functions in engulfing cells. Deletion of vps-18 leads to significant accumulation of cell corpses that are not degraded properly. Furthermore, vps-18 mutation causes strong defects in the biogenesis of endosomes and lysosomes, thus affecting endosomal/lysosomal protein degradation. Importantly, we demonstrate that phagosomes containing internalized cell corpses are unable to fuse with lysosomes in vps-18 mutants. Our findings thus provide direct evidence for the important role of endosomal/lysosomal degradation in proper clearance of apoptotic cells during programmed cell death.

  17. Transgenerational effects of proton beam irradiation on Caenorhabditis elegans germline apoptosis.

    Science.gov (United States)

    Min, Hyemin; Sung, Minhee; Son, Miseol; Kawasaki, Ichiro; Shim, Yhong-Hee

    2017-08-26

    When treating cancer using radiation therapy, it is critical to increase patient survival rates and to reduce side effects. In this respect, proton beam radiation treatment performs better than other radiation treatments because of its high target specificity. However, complications still remain after proton beam radiation treatment. Among them, the risk to progeny after irradiation of their parents is a major concern. In this study, we analyzed the transgenerational effects of proton beam irradiation using the model organism Caenorhabditis. elegans. We found that germline apoptosis increased after proton beam irradiation and its effects were sustained transgenerationally. Moreover, we identified that a germline-specific histone methyltransferase component, SET-2, has a critical role in transmitting the transgenerational effect on germline apoptosis to the next generation after proton beam irradiation. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Facilitation of Endosomal Recycling by an IRG Protein Homolog Maintains Apical Tubule Structure in Caenorhabditis elegans

    Science.gov (United States)

    Grussendorf, Kelly A.; Trezza, Christopher J.; Salem, Alexander T.; Al-Hashimi, Hikmat; Mattingly, Brendan C.; Kampmeyer, Drew E.; Khan, Liakot A.; Hall, David H.; Göbel, Verena; Ackley, Brian D.; Buechner, Matthew

    2016-01-01

    Determination of luminal diameter is critical to the function of small single-celled tubes. A series of EXC proteins, including EXC-1, prevent swelling of the tubular excretory canals in Caenorhabditis elegans. In this study, cloning of exc-1 reveals it to encode a homolog of mammalian IRG proteins, which play roles in immune response and autophagy and are associated with Crohn’s disease. Mutants in exc-1 accumulate early endosomes, lack recycling endosomes, and exhibit abnormal apical cytoskeletal structure in regions of enlarged tubules. EXC-1 interacts genetically with two other EXC proteins that also affect endosomal trafficking. In yeast two-hybrid assays, wild-type and putative constitutively active EXC-1 binds to the LIM-domain protein EXC-9, whose homolog, cysteine-rich intestinal protein, is enriched in mammalian intestine. These results suggest a model for IRG function in forming and maintaining apical tubule structure via regulation of endosomal recycling. PMID:27334269

  19. RNAi targeting Caenorhabditis elegans α-arrestins has small or no effects on lifespan [version 2; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Sangsoon Park

    2017-10-01

    Full Text Available Background: α-arrestins are a family of proteins that are implicated in multiple biological processes, including metabolism and receptor desensitization. Methods: Here, we sought to examine the roles of α-arrestins in the longevity of Caenorhabditis elegans through an RNA interference screen. Results: We found that knocking down each of 24 out of total 29 C. elegans α-arrestins had small or no effects on lifespan. Thus, individual C. elegans α-arrestins may have minor effects on longevity. Conclusions: This study will provide useful information for future research on the functional role of α-arrestins in aging and longevity.

  20. Gene-environment and protein degradation signatures characterize genomic and phenotypic diversity in wild Caenorhabditis elegans populations

    NARCIS (Netherlands)

    Volkers, J.M.; Snoek, L.B.; Hellenberg Hubar, van C.J.; Coopman, R.; Chen, W.; Yang, Wentao; Sterken, M.G.; Schulenburg, H.; Braeckman, B.; Kammenga, J.E.

    2013-01-01

    Background: Analyzing and understanding the relationship between genotypes and phenotypes is at the heart of genetics. Research on the nematode Caenorhabditis elegans has been instrumental for unraveling genotype-phenotype relations, and has important implications for understanding the biology of

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Population dynamics and habitat sharing of natural populations of Caenorhabditis elegans and C. briggsae

    Science.gov (United States)

    2012-01-01

    Background The nematode Caenorhabditis elegans is a major model organism in laboratory biology. Very little is known, however, about its ecology, including where it proliferates. In the past, C. elegans was mainly isolated from human-made compost heaps, where it was overwhelmingly found in the non-feeding dauer diapause stage. Results C. elegans and C. briggsae were found in large, proliferating populations in rotting plant material (fruits and stems) in several locations in mainland France. Both species were found to co-occur in samples isolated from a given plant species. Population counts spanned a range from one to more than 10,000 Caenorhabditis individuals on a single fruit or stem. Some populations with an intermediate census size (10 to 1,000) contained no dauer larvae at all, whereas larger populations always included some larvae in the pre-dauer or dauer stages. We report on associated micro-organisms, including pathogens. We systematically sampled a spatio-temporally structured set of rotting apples in an apple orchard in Orsay over four years. C. elegans and C. briggsae were abundantly found every year, but their temporal distributions did not coincide. C. briggsae was found alone in summer, whereas both species co-occurred in early fall and C. elegans was found alone in late fall. Competition experiments in the laboratory at different temperatures show that C. briggsae out-competes C. elegans at high temperatures, whereas C. elegans out-competes C. briggsae at lower temperatures. Conclusions C. elegans and C. briggsae proliferate in the same rotting vegetal substrates. In contrast to previous surveys of populations in compost heaps, we found fully proliferating populations with no dauer larvae. The temporal sharing of the habitat by the two species coincides with their temperature preference in the laboratory, with C. briggsae populations growing faster than C. elegans at higher temperatures, and vice at lower temperatures. PMID:22731941

  3. New haystacks reveal new needles: using Caenorhabditis elegans to identify novel targets for ameliorating body composition changes during human aging.

    Science.gov (United States)

    Wolkow, Catherine A

    2010-01-01

    Dramatic changes in body composition accompany aging in humans, particularly with respect to adiposity and the musculature. People accumulate fat as they age and lose muscle mass and strength. Caenorhabditis elegans nematodes are small, hermaphroditic soil nematodes that offer a flexible model for studying genetic pathways regulating body composition in humans. While there are significant physiological differences between worms and people, many of the genetic pathways relevant to human lipid and muscle homeostasis are present in worms. Initial studies indicate that adiposity increases in C. elegans during aging, as occurs in humans. Furthermore, substantial evidence demonstrates age-related loss of muscle mass in worms. Possible mechanisms for these changes in C. elegans are presented. Recent studies have highlighted neuroendocrine and environmental signals regulating C. elegans fat metabolism. Potential dysfunction of these pathways during aging could affect overall fat accumulation. By contrast, muscle decline in aging worms results from accumulated damage and 'wear-and-tear' over life span. However, neuroendocrine pathways also regulate muscle mass in response to food availability. Such pathways might provide useful therapeutic approaches for combating muscle loss during aging. From this chapter, readers will develop a deeper understanding of the ways that C.elegans can be used for mechanistic gerontological studies. Copyright © 2010 S. Karger AG, Basel.

  4. The TRA-1 transcription factor binds TRA-2 to regulate sexual fates in Caenorhabditis elegans

    Science.gov (United States)

    Wang, Shanping; Kimble, Judith

    2001-01-01

    The tra-1 and tra-2 sex-determining genes promote female fates in Caenorhabditis elegans. Classical genetic studies placed tra-1 as the terminal regulator of the pathway with tra-2 acting upstream as a regulator of regulators of tra-1. Here we report the surprising result that the TRA-1 transcription factor binds the intracellular domain of the TRA-2 membrane protein. This binding is dependent on the MX regulatory domain, a region of the TRA-2 intracellular domain shown previously to be critical for the onset of hermaphrodite spermatogenesis. The functional importance of the TRA-1–TRA-2 physical interaction is supported by genetic interactions between tra-1(0) and tra-2(mx) mutations: a reduction of tra-1 gene dose from two copies to one copy enhances the tra-2(mx) feminization phenotype, but has no apparent somatic effect. In Caenorhabditis briggsae, we also find an MX-dependent interaction between Cb-TRA-1 and Cb-TRA-2, but intriguingly, no cross-species interactions are seen. The conservation of the TRA-1– TRA-2 interaction underscores its importance in sex determination. PMID:11250902

  5. Sensory organ remodeling in Caenorhabditis elegans requires the zinc-finger protein ZTF-16.

    Science.gov (United States)

    Procko, Carl; Lu, Yun; Shaham, Shai

    2012-04-01

    Neurons and glia display remarkable morphological plasticity, and remodeling of glia may facilitate neuronal shape changes. The molecular basis and control of glial shape changes is not well understood. In response to environmental stress, the nematode Caenorhabditis elegans enters an alternative developmental state, called dauer, in which glia and neurons of the amphid sensory organ remodel. Here, we describe a genetic screen aimed at identifying genes required for amphid glia remodeling. We previously demonstrated that remodeling requires the Otx-type transcription factor TTX-1 and its direct target, the receptor tyrosine kinase gene ver-1. We now find that the hunchback/Ikaros-like C2H2 zinc-finger factor ztf-16 is also required. We show that ztf-16 mutants exhibit pronounced remodeling defects, which are explained, at least in part, by defects in the expression of ver-1. Expression and cell-specific rescue studies suggest that ztf-16, like ttx-1, functions within glia; however, promoter deletion studies show that ztf-16 acts through a site on the ver-1 promoter that is independent of ttx-1. Our studies identify an important component of glia remodeling and suggest that transcriptional changes may underlie glial morphological plasticity in the sensory organs of C. elegans.

  6. Dopamine modulates acetylcholine release via octopamine and CREB signaling in Caenorhabditis elegans.

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    Satoshi Suo

    Full Text Available Animals change their behavior and metabolism in response to external stimuli. cAMP response element binding protein (CREB is a signal-activated transcription factor that enables the coupling of extracellular signals and gene expression to induce adaptive changes. Biogenic amine neurotransmitters regulate CREB and such regulation is important for long-term changes in various nervous system functions, including learning and drug addiction. In Caenorhabditis elegans, the amine neurotransmitter octopamine activates a CREB homolog, CRH-1, in cholinergic SIA neurons, whereas dopamine suppresses CREB activation by inhibiting octopamine signaling in response to food stimuli. However, the physiological role of this activation is unknown. In this study, the effect of dopamine, octopamine, and CREB on acetylcholine signaling was analyzed using the acetylcholinesterase inhibitor aldicarb. Mutants with decreased dopamine signaling exhibited reduced acetylcholine signaling, and octopamine and CREB functioned downstream of dopamine in this regulation. This study demonstrates that the regulation of CREB by amine neurotransmitters modulates acetylcholine release from the neurons of C. elegans.

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

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    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.

  8. Spatiotemporal localization of D-amino acid oxidase and D-aspartate oxidases during development in Caenorhabditis elegans.

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    Saitoh, Yasuaki; Katane, Masumi; Kawata, Tomonori; Maeda, Kazuhiro; Sekine, Masae; Furuchi, Takemitsu; Kobuna, Hiroyuki; Sakamoto, Taro; Inoue, Takao; Arai, Hiroyuki; Nakagawa, Yasuhito; Homma, Hiroshi

    2012-05-01

    Recent investigations have shown that a variety of D-amino acids are present in living organisms and that they possibly play important roles in physiological functions in the body. D-Amino acid oxidase (DAO) and D-aspartate oxidase (DDO) are degradative enzymes stereospecific for D-amino acids. They have been identified in various organisms, including mammals and the nematode Caenorhabditis elegans, although the significance of these enzymes and the relevant functions of D-amino acids remain to be elucidated. In this study, we investigated the spatiotemporal localization of C. elegans DAO and DDOs (DDO-1, DDO-2, and DDO-3) and measured the levels of several D- and L-amino acids in wild-type C. elegans and four mutants in which each gene for DAO and the DDOs was partially deleted and thereby inactivated. Furthermore, several phenotypes of these mutant strains were characterized. The results reported in this study indicate that C. elegans DAO and DDOs are involved in egg-laying events and the early development of C. elegans. In particular, DDOs appear to play important roles in the development and maturation of germ cells. This work provides novel and useful insights into the physiological functions of these enzymes and D-amino acids in multicellular organisms.

  9. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

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    Qiangqiang Wang

    2016-01-01

    Full Text Available Since excessive reactive oxygen species (ROS is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps, which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction.

  10. Adverse effects from clenbuterol and ractopamine on nematode Caenorhabditis elegans and the underlying mechanism.

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    Ziheng Zhuang

    Full Text Available In the present study, we used Caenorhabditis elegans assay system to investigate in vivo toxicity from clentuberol and ractopamine and the possible underlying mechanism. Both acute and prolonged exposures to clentuberol or ractopamine decreased brood size and locomotion behavior, and induced intestinal autofluorescence and reactive oxygen species (ROS production. Although acute exposure to the examined concentrations of clentuberol or ractopamine did not induce lethality, prolonged exposure to 10 µg/L of clentuberol and ractopamine reduced lifespan. At relatively high concentrations, ractopamine exhibited more severe toxicity than clentuberol on nematodes. Overexpression of sod-2 gene encoding a Mn-SOD to prevent induction of oxidative stress effectively inhibited toxicity from clentuberol or ractopamine. Besides oxidative stress, we found that clentuberol might reduce lifespan through influencing insulin/IGF signaling pathway; however, ractopamine might reduce lifespan through affecting both insulin/IGF signaling pathway and TOR signaling pathway. Ractopamine more severely decreased expression levels of daf-16, sgk-1, skn-1, and aak-2 genes than clentuberol, and increased expression levels of daf-2 and age-1 genes at the examined concentration. Therefore, the C. elegans assay system may be useful for assessing the possible toxicity from weight loss agents, and clentuberol and ractopamine may induce toxicity through different molecular mechanisms.

  11. Pollution breaks down the genetic architecture of life history traits in Caenorhabditis elegans.

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    Morgan Dutilleul

    Full Text Available When pollution occurs in an environment, populations present suffer numerous negative and immediate effects on their life history traits. Their evolutionary potential to live in a highly stressful environment will depend on the selection pressure strengths and on the genetic structure, the trait heritability, and the genetic correlations between them. If expression of this structure changes in a stressful environment, it becomes necessary to quantify these changes to estimate the evolutionary potential of the population in this new environment. We studied the genetic structure for survival, fecundity, and early and late growth in isogenic lines of a Caenorhabditis elegans population subject to three different environments: a control environment, an environment polluted with uranium, and a high salt concentration environment. We found a heritability decrease in the polluted environments for fecundity and early growth, two traits that were the most heritable in the control environment. The genetic structure of the traits was particularly affected in the uranium polluted environment, probably due to generally low heritability in this environment. This could prevent selection from acting on traits despite the strong selection pressures exerted on them. Moreover, phenotypic traits were more strongly affected in the salt than in the uranium environment and the heritabilities were also lower in the latter environment. Consequently the decrease in heritability was not proportional to the population fitness reduction in the polluted environments. Our results suggest that pollution can alter the genetic structure of a C. elegans population, and thus modify its evolutionary potential.

  12. Postcopulatory sexual selection reduces genetic diversity in experimental populations of Caenorhabditis elegans.

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    LaMunyon, Craig W; Bouban, Oussama; Cutter, Asher D

    2007-01-01

    Postcopulatory sexual selection affects the evolution of numerous features ranging from mating behavior to seminal fluid toxicity to the size of gametes. In an earlier study of the effect of sperm competition risk on sperm size evolution, experimental populations of the nematode Caenorhabditis elegans were maintained either by outcrossing (sperm competition present) or by selfing (no sperm competition), and after 60 generations, significantly larger sperm had evolved in the outcrossing populations. To determine the effects of this selection on population genetic variation, we assessed genetic diversity in a large number of loci using random amplification of polymorphic DNA-PCR. Nearly 80% of the alleles present in parental strain populations persisted in the 6 experimental populations after the 60 generations and, despite a 2.2-fold difference in expected heterozygosity, the resulting levels of genetic variation were equivalent between the outcrossing and selfing experimental populations. By inference, we conclude that genetic hitchhiking due to sexual selection in the experimental populations dramatically reduced genetic diversity. We use the levels of variation in the selfing populations as a control for the effects of drift, and estimate the strength of sexual selection to be strong in obligatorily outcrossing populations. Although sequential hermaphrodites like C. elegans probably experience little sexual selection in nature, these data suggest that sexual selection can profoundly affect diversity in outcrossing taxa.

  13. Computational and experimental identification of mirtrons in Drosophila melanogaster and Caenorhabditis elegans

    Science.gov (United States)

    Chung, Wei-Jen; Agius, Phaedra; Westholm, Jakub O.; Chen, Michael; Okamura, Katsutomo; Robine, Nicolas; Leslie, Christina S.; Lai, Eric C.

    2011-01-01

    Mirtrons are intronic hairpin substrates of the dicing machinery that generate functional microRNAs. In this study, we describe experimental assays that defined the essential requirements for entry of introns into the mirtron pathway. These data informed a bioinformatic screen that effectively identified functional mirtrons from the Drosophila melanogaster transcriptome. These included 17 known and six confident novel mirtrons among the top 51 candidates, and additional candidates had limited read evidence in available small RNA data. Our computational model also proved effective on Caenorhabditis elegans, for which the identification of 14 cloned mirtrons among the top 22 candidates more than tripled the number of validated mirtrons in this species. A few low-scoring introns generated mirtron-like read patterns from atypical RNA structures, but their paucity suggests that relatively few such loci were not captured by our model. Unexpectedly, we uncovered examples of clustered mirtrons in both fly and worm genomes, including a <8-kb region in C. elegans harboring eight distinct mirtrons. Altogether, we demonstrate that discovery of functional mirtrons, unlike canonical miRNAs, is amenable to computational methods independent of evolutionary constraint. PMID:21177960

  14. Astragalus Polysaccharide Suppresses 6-Hydroxydopamine-Induced Neurotoxicity in Caenorhabditis elegans

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    Haifeng Li

    2016-01-01

    Full Text Available Astragalus membranaceus is a medicinal plant traditionally used in China for a variety of conditions, including inflammatory and neural diseases. Astragalus polysaccharides are shown to reduce the adverse effect of levodopa which is used to treat Parkinson’s disease (PD. However, the neuroprotective effect of Astragalus polysaccharides per se in PD is lacking. Using Caenorhabditis elegans models, we investigated the protective effect of astragalan, an acidic polysaccharide isolated from A. membranaceus, against the neurotoxicity of 6-hydroxydopamine (6-OHDA, a neurotoxin that can induce parkinsonism. We show that 6-OHDA is able to degenerate dopaminergic neurons and lead to the deficiency of food-sensing behavior and a shorter lifespan in C. elegans. Interestingly, these degenerative symptoms can be attenuated by astragalan treatment. Astragalan is also shown to alleviate oxidative stress through reducing reactive oxygen species level and malondialdehyde content and increasing superoxide dismutase and glutathione peroxidase activities and reduce the expression of proapoptotic gene egl-1 in 6-OHDA-intoxicated nematodes. Further studies reveal that astragalan is capable of elevating the decreased acetylcholinesterase activity induced by 6-OHDA. Together, our results demonstrate that the protective effect of astragalan against 6-OHDA neurotoxicity is likely due to the alleviation of oxidative stress and regulation of apoptosis pathway and cholinergic system and thus provide an important insight into the therapeutic potential of Astragalus polysaccharide in neurodegeneration.

  15. Ras/MAPK Modifier Loci Revealed by eQTL in Caenorhabditis elegans

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    Mark G. Sterken

    2017-09-01

    Full Text Available The oncogenic Ras/MAPK pathway is evolutionarily conserved across metazoans. Yet, almost all our knowledge on this pathway comes from studies using single genetic backgrounds, whereas mutational effects can be highly background dependent. Therefore, we lack insight in the interplay between genetic backgrounds and the Ras/MAPK-signaling pathway. Here, we used a Caenorhabditis elegans RIL population containing a gain-of-function mutation in the Ras/MAPK-pathway gene let-60 and measured how gene expression regulation is affected by this mutation. We mapped eQTL and found that the majority (∼73% of the 1516 detected cis-eQTL were not specific for the let-60 mutation, whereas most (∼76% of the 898 detected trans-eQTL were associated with the let-60 mutation. We detected six eQTL trans-bands specific for the interaction between the genetic background and the mutation, one of which colocalized with the polymorphic Ras/MAPK modifier amx-2. Comparison between transgenic lines expressing allelic variants of amx-2 showed the involvement of amx-2 in 79% of the trans-eQTL for genes mapping to this trans-band. Together, our results have revealed hidden loci affecting Ras/MAPK signaling using sensitized backgrounds in C. elegans. These loci harbor putative polymorphic modifier genes that would not have been detected using mutant screens in single genetic backgrounds.

  16. UGT-29 protein expression and localization during bacterial infection in Caenorhabditis elegans

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    Wong, Rui-Rui; Lee, Song-Hua; Nathan, Sheila

    2014-09-01

    The nematode Caenorhabditis elegans is routinely used as an animal model to delineate complex molecular mechanisms involved in the host response to pathogen infection. Following up on an earlier study on host-pathogen interaction, we constructed a ugt-29::GFP transcriptional fusion transgenic worm strain to examine UGT-29 protein expression and localization upon bacterial infection. UGT-29 orthologs can be found in higher organisms including humans and is proposed as a member of the UDP-Glucoronosyl Transferase family of proteins which are involved in phase II detoxification of compounds detrimental to the host organism. Under uninfected conditions, UGT-29::GFP fusion protein was highly expressed in the C. elegans anterior pharynx and intestine, two major organs involved in detoxification. We further evaluated the localization of the enzyme in worms infected with the bacterial pathogen, Burkholderia pseudomallei. The infected ugt-29::GFP transgenic strain exhibited increased fluorescence in the pharynx and intestine with pronounced fluorescence also extending to body wall muscle. This transcriptional fusion GFP transgenic worm is a convenient and direct tool to provide information on UGT detoxification enzyme gene expression and could be a useful tool for a number of diverse applications.

  17. Astragalus Polysaccharide Suppresses 6-Hydroxydopamine-Induced Neurotoxicity in Caenorhabditis elegans

    Science.gov (United States)

    Li, Haifeng; Ding, Fei; Wang, Hongyu; Han, Wenjing; Ma, Fangli; Hu, Minghua; Ma, Chung Wah

    2016-01-01

    Astragalus membranaceus is a medicinal plant traditionally used in China for a variety of conditions, including inflammatory and neural diseases. Astragalus polysaccharides are shown to reduce the adverse effect of levodopa which is used to treat Parkinson's disease (PD). However, the neuroprotective effect of Astragalus polysaccharides per se in PD is lacking. Using Caenorhabditis elegans models, we investigated the protective effect of astragalan, an acidic polysaccharide isolated from A. membranaceus, against the neurotoxicity of 6-hydroxydopamine (6-OHDA), a neurotoxin that can induce parkinsonism. We show that 6-OHDA is able to degenerate dopaminergic neurons and lead to the deficiency of food-sensing behavior and a shorter lifespan in C. elegans. Interestingly, these degenerative symptoms can be attenuated by astragalan treatment. Astragalan is also shown to alleviate oxidative stress through reducing reactive oxygen species level and malondialdehyde content and increasing superoxide dismutase and glutathione peroxidase activities and reduce the expression of proapoptotic gene egl-1 in 6-OHDA-intoxicated nematodes. Further studies reveal that astragalan is capable of elevating the decreased acetylcholinesterase activity induced by 6-OHDA. Together, our results demonstrate that the protective effect of astragalan against 6-OHDA neurotoxicity is likely due to the alleviation of oxidative stress and regulation of apoptosis pathway and cholinergic system and thus provide an important insight into the therapeutic potential of Astragalus polysaccharide in neurodegeneration. PMID:27885333

  18. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

    Science.gov (United States)

    Wang, Qiangqiang; Huang, Yunxuan; Qin, Chuixin; Liang, Ming; Mao, Xinliang; Li, Shuiming; Zou, Yongdong; Jia, Weizhang; Li, Haifeng; Ma, Chung Wah; Huang, Zebo

    2016-01-01

    Since excessive reactive oxygen species (ROS) is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa) was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps), which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps) are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction. PMID:26941890

  19. A new Caenorhabditis elegans model of human huntingtin 513 aggregation and toxicity in body wall muscles.

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    Amy L Lee

    Full Text Available Expanded polyglutamine repeats in different proteins are the known determinants of at least nine progressive neurodegenerative disorders whose symptoms include cognitive and motor impairment that worsen as patients age. One such disorder is Huntington's Disease (HD that is caused by a polyglutamine expansion in the human huntingtin protein (htt. The polyglutamine expansion destabilizes htt leading to protein misfolding, which in turn triggers neurodegeneration and the disruption of energy metabolism in muscle cells. However, the molecular mechanisms that underlie htt proteotoxicity have been somewhat elusive, and the muscle phenotypes have not been well studied. To generate tools to elucidate the basis for muscle dysfunction, we engineered Caenorhabditis elegans to express a disease-associated 513 amino acid fragment of human htt in body wall muscle cells. We show that this htt fragment aggregates in C. elegans in a polyglutamine length-dependent manner and is toxic. Toxicity manifests as motor impairment and a shortened lifespan. Compared to previous models, the data suggest that the protein context in which a polyglutamine tract is embedded alters aggregation propensity and toxicity, likely by affecting interactions with the muscle cell environment.

  20. Behavior of Caenorhabditis elegans in a nicotine gradient modulated by food.

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    Sobkowiak, Robert; Kaczmarek, Piotr; Kowalski, Mateusz; Kabaciński, Rafał; Lesicki, Andrzej

    2017-12-04

    Nicotine decreases food intake, and smokers often report that they smoke to control their weight. To see whether similar phenomena could be observed in the model organism Caenorhabditis elegans, we challenged drug-naïve nematodes with a chronic low (0.01 mM) and high (1 mM) nicotine concentration for 55 h (from hatching to adulthood). After that, we recorded changes in their behavior in a nicotine gradient, where they could choose a desired nicotine concentration. By using a combination of behavioral and morphometric methods, we found that both nicotine and food modulate worm behavior. In the presence of food (E. coli OP50) the nematodes adapted to the low nicotine concentration, when placed in the gradient, chose a similar nicotine concentration like C. elegans adapted to the high nicotine concentration. However, in the absence of food, the nematodes adapted to the low nicotine concentration, when placed in the gradient of this alkaloid, chose a similar nicotine concentration like naïve worms. The nematodes growing up in the presence of high concentrations of nicotine had a statistically smaller body size, compared to the control condition, and the presence of food did not cause any enhanced slowing movement. These results provide a platform for more detailed molecular and cellular studies of nicotine addiction and food intake in this model organism.

  1. The Energy Metabolism in Caenorhabditis elegans under The Extremely Low-Frequency Electromagnetic Field Exposure

    Science.gov (United States)

    Shi, Zhenhua; Yu, Hui; Sun, Yongyan; Yang, Chuanjun; Lian, Huiyong; Cai, Peng

    2015-02-01

    A literal mountain of documentation generated in the past five decades showing unmistakable health hazards associated with extremely low-frequency electromagnetic fields (ELF-EMFs) exposure. However, the relation between energy mechanism and ELF-EMF exposure is poorly understood. In this study, Caenorhabditis elegans was exposed to 50 Hz ELF-EMF at intensities of 0.5, 1, 2, and 3 mT, respectively. Their metabolite variations were analyzed by GC-TOF/MS-based metabolomics. Although minimal metabolic variations and no regular pattern were observed, the contents of energy metabolism-related metabolites such as pyruvic acid, fumaric acid, and L-malic acid were elevated in all the treatments. The expressions of nineteen related genes that encode glycolytic enzymes were analyzed by using quantitative real-time PCR. Only genes encoding GAPDH were significantly upregulated (P worms exposed to ELF-EMF exhibited less food consumption compared with that of the control (P < 0.01). In conclusion, C. elegans exposed to ELF-EMF have enhanced energy metabolism and restricted dietary, which might contribute to the resistance against exogenous ELF-EMF stress.

  2. Comparative Lipidomics of Caenorhabditis elegans Metabolic Disease Models by SWATH Non-Targeted Tandem Mass Spectrometry

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    Jeevan K. Prasain

    2015-11-01

    Full Text Available Tandem mass spectrometry (MS/MS with Sequential Window Acquisition of all Theoretical (SWATH mass spectra generates a comprehensive archive of lipid species within an extract for retrospective, quantitative MS/MS analysis. Here we apply this new technology in Caenorhabditis elegans (C. elegans to identify potential lipid mediators and pathways. The DAF-1 type I TGF-β and DAF-2 insulin receptors transmit endocrine signals that couple metabolic status to fertility and lifespan. Mutations in daf-1 and daf-2 reduce prostaglandin-endoperoxide synthase (i.e., Cox-independent prostaglandin synthesis, increase triacylglyceride storage, and alter transcription of numerous lipid metabolism genes. However, the extent to which DAF-1 and DAF-2 signaling modulate lipid metabolism and the underlying mechanisms are not well understood. MS/MSALL with SWATH analysis across the groups identified significant changes in numerous lipids, including specific triacylglycerols, diacylglycerols, and phosphatidylinositols. Examples are provided, using retrospective neutral loss and precursor ion scans as well as MS/MS spectra, to help identify annotated lipids and search libraries for lipids of interest. As proof of principle, we used comparative lipidomics to investigate the prostaglandin metabolism pathway. SWATH data support an unanticipated model: Cox-independent prostaglandin synthesis may involve lysophosphatidylcholine and other lyso glycerophospholipids. This study showcases the power of comprehensive, retrospectively searchable lipid archives as a systems approach for biological discovery in genetic animal models.

  3. Sorbitol treatment extends lifespan and induces the osmotic stress response in Caenorhabditis elegans

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    Devon eChandler-Brown

    2015-10-01

    Full Text Available The response to osmotic stress is a highly conserved process for adapting to changing environmental conditions. Prior studies have shown that hyperosmolarity by addition of sorbitol to the growth medium is sufficient to increase both chronological and replicative lifespan in the budding yeast, Saccharomyces cerevisiae. Here we report a similar phenomenon in the nematode Caenorhabditis elegans. Addition of sorbitol to the nematode growth medium induces an adaptive osmotic response and increases C. elegans lifespan by about 35%. Lifespan extension from 5% sorbitol behaves similarly to dietary restriction in a variety of genetic backgrounds, increasing lifespan additively with mutation of daf-2(e1370 and independently of daf-16(mu86, sir-2.1(ok434, aak-2(ok524, and hif-1(ia04. Dietary restriction by bacterial deprivation or mutation of eat-2(ad1113 fails to further extend lifespan in the presence of 5% sorbitol. Two mutants with constitutive activation of the osmotic response, osm-5(p813 and osm-7(n1515, were found to be long-lived, and lifespan extension from sorbitol required the glycerol biosynthetic enzymes GPDH-1 and GPDH-2. Taken together, these observations demonstrate that exposure to sorbitol at levels sufficient to induce an adaptive osmotic response extends lifespan in worms and define the osmotic stress response pathway as a longevity pathway conserved between yeast and nematodes.

  4. Network control principles predict neuron function in the Caenorhabditis elegans connectome

    Science.gov (United States)

    Yan, Gang; Vértes, Petra E.; Towlson, Emma K.; Chew, Yee Lian; Walker, Denise S.; Schafer, William R.; Barabási, Albert-László

    2017-10-01

    Recent studies on the controllability of complex systems offer a powerful mathematical framework to systematically explore the structure–function relationship in biological, social, and technological networks. Despite theoretical advances, we lack direct experimental proof of the validity of these widely used control principles. Here we fill this gap by applying a control framework to the connectome of the nematode Caenorhabditis elegans, allowing us to predict the involvement of each C. elegans neuron in locomotor behaviours. We predict that control of the muscles or motor neurons requires 12 neuronal classes, which include neuronal groups previously implicated in locomotion by laser ablation, as well as one previously uncharacterized neuron, PDB. We validate this prediction experimentally, finding that the ablation of PDB leads to a significant loss of dorsoventral polarity in large body bends. Importantly, control principles also allow us to investigate the involvement of individual neurons within each neuronal class. For example, we predict that, within the class of DD motor neurons, only three (DD04, DD05, or DD06) should affect locomotion when ablated individually. This prediction is also confirmed; single cell ablations of DD04 or DD05 specifically affect posterior body movements, whereas ablations of DD02 or DD03 do not. Our predictions are robust to deletions of weak connections, missing connections, and rewired connections in the current connectome, indicating the potential applicability of this analytical framework to larger and less well-characterized connectomes.

  5. Heat shock factor 1 prevents the reduction in thrashing due to heat shock in Caenorhabditis elegans.

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    Furuhashi, Tsubasa; Sakamoto, Kazuichi

    2015-07-03

    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. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Regulator of Calcineurin (RCAN-1) Regulates Thermotaxis Behavior in Caenorhabditis elegans.

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    Li, Weixun; Bell, Harold W; Ahnn, Joohong; Lee, Sun-Kyung

    2015-11-06

    Regulator of calcineurin (RCAN) is a calcineurin-interacting protein that inhibits calcineurin phosphatase when overexpressed, often upregulated under neuropathological conditions with impaired learning and memory processes, such as Down syndrome or Alzheimer's disease. Thermotactic behavior in the nematode Caenorhabditis elegans is a form of memory in which calcineurin signaling plays a pivotal role in the thermosensation of AFD neurons. In this study, we found that rcan-1 deletion mutants exhibited cryophilic behavior dependent on tax-6, which was rescued by expressing rcan-1 in AFD neurons. Interaction between RCAN-1 and TAX-6 requires the conserved PxIxIT motif of RCAN-1, without which thermotactic behavior could not be fully rescued. In addition, the loss of crh-1/CREB suppressed the thermotaxis phenotypes of rcan-1 and tax-6 mutants, indicating that crh-1 is crucial in thermotaxis memory in these mutants. Taken together, our results suggest that rcan-1 is an inhibitory regulator of tax-6 and that it acts in the formation of thermosensory behavioral memory in C. elegans. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Endogenous RNAi Pathways Are Required in Neurons for Dauer Formation in Caenorhabditis elegans.

    Science.gov (United States)

    Bharadwaj, Pallavi S; Hall, Sarah E

    2017-04-01

    Animals can adapt to unfavorable environments through changes in physiology or behavior. In the nematode, Caenorhabditis elegans, environmental conditions perceived early in development determine whether the animal enters either the reproductive cycle, or enters into an alternative diapause stage named dauer. Here, we show that endogenous RNAi pathways play a role in dauer formation in crowding (high pheromone), starvation, and high temperature conditions. Disruption of the Mutator proteins or the nuclear Argonaute CSR-1 result in differential dauer-deficient phenotypes that are dependent upon the experienced environmental stress. We provide evidence that the RNAi pathways function in chemosensory neurons for dauer formation, upstream of the TGF-β and insulin signaling pathways. In addition, we show that Mutator MUT-16 expression in a subset of individual pheromone-sensing neurons is sufficient for dauer formation in high pheromone conditions, but not in starvation or high temperature conditions. Furthermore, we also show that MUT-16 and CSR-1 are required for expression of a subset of G proteins with functions in the detection of pheromone components. Together, our data suggest a model where Mutator-amplified siRNAs that associate with the CSR-1 pathway promote expression of genes required for the detection and signaling of environmental conditions to regulate development and behavior in C. elegans This study highlights a mechanism whereby RNAi pathways mediate the link between environmental stress and adaptive phenotypic plasticity in animals. Copyright © 2017 by the Genetics Society of America.

  8. In vitro and in vivo reconstitution of the cadherin–catenin–actin complex from Caenorhabditis elegans

    Science.gov (United States)

    Kwiatkowski, Adam V.; Maiden, Stephanie L.; Pokutta, Sabine; Choi, Hee-Jung; Benjamin, Jacqueline M.; Lynch, Allison M.; Nelson, W. James; Weis, William I.; Hardin, Jeff

    2010-01-01

    The ternary complex of cadherin, β-catenin, and α-catenin regulates actin-dependent cell–cell adhesion. α-Catenin can bind β-catenin and F-actin, but in mammals α-catenin either binds β-catenin as a monomer or F-actin as a homodimer. It is not known if this conformational regulation of α-catenin is evolutionarily conserved. The Caenorhabditis elegans α-catenin homolog HMP-1 is essential for actin-dependent epidermal enclosure and embryo elongation. Here we show that HMP-1 is a monomer with a functional C-terminal F-actin binding domain. However, neither full-length HMP-1 nor a ternary complex of HMP-1–HMP-2(β-catenin)–HMR-1(cadherin) bind F-actin in vitro, suggesting that HMP-1 is auto-inhibited. Truncation of either the F-actin or HMP-2 binding domain of HMP-1 disrupts C. elegans development, indicating that HMP-1 must be able to bind F-actin and HMP-2 to function in vivo. Our study defines evolutionarily conserved properties of α-catenin and suggests that multiple mechanisms regulate α-catenin binding to F-actin. PMID:20689042

  9. In vitro and in vivo reconstitution of the cadherin-catenin-actin complex from Caenorhabditis elegans.

    Science.gov (United States)

    Kwiatkowski, Adam V; Maiden, Stephanie L; Pokutta, Sabine; Choi, Hee-Jung; Benjamin, Jacqueline M; Lynch, Allison M; Nelson, W James; Weis, William I; Hardin, Jeff

    2010-08-17

    The ternary complex of cadherin, beta-catenin, and alpha-catenin regulates actin-dependent cell-cell adhesion. alpha-Catenin can bind beta-catenin and F-actin, but in mammals alpha-catenin either binds beta-catenin as a monomer or F-actin as a homodimer. It is not known if this conformational regulation of alpha-catenin is evolutionarily conserved. The Caenorhabditis elegans alpha-catenin homolog HMP-1 is essential for actin-dependent epidermal enclosure and embryo elongation. Here we show that HMP-1 is a monomer with a functional C-terminal F-actin binding domain. However, neither full-length HMP-1 nor a ternary complex of HMP-1-HMP-2(beta-catenin)-HMR-1(cadherin) bind F-actin in vitro, suggesting that HMP-1 is auto-inhibited. Truncation of either the F-actin or HMP-2 binding domain of HMP-1 disrupts C. elegans development, indicating that HMP-1 must be able to bind F-actin and HMP-2 to function in vivo. Our study defines evolutionarily conserved properties of alpha-catenin and suggests that multiple mechanisms regulate alpha-catenin binding to F-actin.

  10. Pollution breaks down the genetic architecture of life history traits in Caenorhabditis elegans.

    Science.gov (United States)

    Dutilleul, Morgan; Goussen, Benoit; Bonzom, Jean-Marc; Galas, Simon; Réale, Denis

    2015-01-01

    When pollution occurs in an environment, populations present suffer numerous negative and immediate effects on their life history traits. Their evolutionary potential to live in a highly stressful environment will depend on the selection pressure strengths and on the genetic structure, the trait heritability, and the genetic correlations between them. If expression of this structure changes in a stressful environment, it becomes necessary to quantify these changes to estimate the evolutionary potential of the population in this new environment. We studied the genetic structure for survival, fecundity, and early and late growth in isogenic lines of a Caenorhabditis elegans population subject to three different environments: a control environment, an environment polluted with uranium, and a high salt concentration environment. We found a heritability decrease in the polluted environments for fecundity and early growth, two traits that were the most heritable in the control environment. The genetic structure of the traits was particularly affected in the uranium polluted environment, probably due to generally low heritability in this environment. This could prevent selection from acting on traits despite the strong selection pressures exerted on them. Moreover, phenotypic traits were more strongly affected in the salt than in the uranium environment and the heritabilities were also lower in the latter environment. Consequently the decrease in heritability was not proportional to the population fitness reduction in the polluted environments. Our results suggest that pollution can alter the genetic structure of a C. elegans population, and thus modify its evolutionary potential.

  11. The Evaluation of Geroprotective Effects of Selected Flavonoids in Drosophila melanogaster and Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Ekaterina Lashmanova

    2017-12-01

    Full Text Available Flavonoids is an intensively studied group of natural compounds with antioxidant, antineoplastic, antihyperglycemic, cardioprotective, and neuroprotective properties. The present study intends to investigate the geroprotective action of three selected flavonoids (naringin, luteolin, chrysin in two model organisms, Caenorhabditis elegans and Drosophila melanogaster. Luteolin and chrysin were shown to improve lifespan parameters when administered to both model organisms. The observed positive effects of these flavonoids in D. melanogaster were limited to females and were not associated with reduced fecundity or locomotor impairment. The life-extending effects of flavonoids were observed in N2 wild-type worms but absent in aak-2(gt33 mutants implying that these effects can be associated with AMP-activated protein kinase activity. Naringin improved lifespan parameters of C. elegans, but had no effect on D. melanogaster females; in some cases, naringin was found to decrease the lifespan of males. Compared to chrysin and luteolin, however, naringin more effectively activates Nrf2 target genes (particularly, GstD1 under oxidative stress. Then we compared molecular mechanisms of studied compounds and a well-known geroprotector rapamycin, using software tool GeroScope. There are no transcriptomic data on luteolin or chrysin provided by LINCS Project database. The bioinformatics comparison of transcriptomics data for A549 and MCF7 human cell lines treated with rapamycin or naringin revealed that these compounds share just a few common signaling pathways and quite distinct in their geroprotective action. Thus, based on C. elegans effects of naringin, luteolin, chrysin on lifespan we have revealed new potential geroprotectors.

  12. Legionella-protozoa-nematode interactions in aquatic biofilms and influence of Mip on Caenorhabditis elegans colonization.

    Science.gov (United States)

    Rasch, Janine; Krüger, Stefanie; Fontvieille, Dominique; Ünal, Can M; Michel, Rolf; Labrosse, Aurélie; Steinert, Michael

    2016-09-01

    Legionella pneumophila, the causative agent of Legionnaireś disease, is naturally found in aquatic habitats. The intracellular life cycle within protozoa pre-adapted the "accidental" human pathogen to also infect human professional phagocytes like alveolar macrophages. Previous studies employing the model organism Caenorhabditis elegans suggest that also nematodes might serve as a natural host for L. pneumophila. Here, we report for the first time from a natural co-habitation of L. pneumophila and environmental nematode species within biofilms of a warm water spring. In addition, we identified the protozoan species Oxytricha bifaria, Stylonychia mytilus, Ciliophrya sp. which have never been described as potential interaction partners of L. pneumophila before. Modeling and dissection of the Legionella-protozoa-nematode interaction revealed that C. elegans ruptures Legionella-infected amoebal cells and by this means incorporate the pathogen. Further infection studies revealed that the macrophage infectivity potentiator (Mip) protein of L. pneumophila, which is known to bind collagen IV during human lung infection, promotes the colonization of the intestinal tract of L4 larvae of C. elegans and negatively influences the life span of the worms. The Mip-negative L. pneumophila mutant exhibited a 32-fold reduced colonization rate of the nematodes after 48h when compared to the wild-type strain. Taken together, these studies suggest that nematodes may serve as natural hosts for L. pneumophila, promote their persistence and dissemination in the environment, and co-evolutionarily pre-adapt the pathogen for interactions with extracellular constituents of human lung tissue. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Characterization of microsporidia-induced developmental arrest and a transmembrane leucine-rich repeat protein in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Robert J Luallen

    Full Text Available Microsporidia comprise a highly diverged phylum of intracellular, eukaryotic pathogens, with some species able to cause life-threatening illnesses in immunocompromised patients. To better understand microsporidian infection in animals, we study infection of the genetic model organism Caenorhabditis elegans and a species of microsporidia, Nematocida parisii, which infects Caenorhabditis nematodes in the wild. We conducted a targeted RNAi screen for host C. elegans genes important for infection and growth of N. parisii, using nematode larval arrest as an assay for infection. Here, we present the results of this RNAi screen, and our analyses on one of the RNAi hits from the screen that was ultimately not corroborated by loss of function mutants. This hit was an RNAi clone against F56A8.3, a conserved gene that encodes a transmembrane protein containing leucine-rich repeats (LRRs, a domain found in numerous pathogen receptors from other systems. This RNAi clone caused C. elegans to be resistant to infection by N. parisii, leading to reduced larval arrest and lower pathogen load. Characterization of the endogenous F56A8.3 protein revealed that it is expressed in the intestine, localized to the membrane around lysosome-related organelles (LROs, and exists in two different protein isoforms in C. elegans. We used the CRISPR-Cas9 system to edit the F56A8.3 locus and created both a frameshift mutant resulting in a truncated protein and a complete knockout mutant. Neither of these mutants was able to recapitulate the infection phenotypes of the RNAi clone, indicating that the RNAi-mediated phenotypes are due to an off-target effect of the RNAi clone. Nevertheless, this study describes microsporidia-induced developmental arrest in C. elegans, presents results from an RNAi screen for host genes important for microsporidian infection, and characterizes aspects of the conserved F56A8.3 gene and its protein product.

  14. Oxidation resistance 1 is essential for protection against oxidative stress and participates in the regulation of aging in Caenorhabditis elegans.

    Science.gov (United States)

    Sanada, Y; Asai, S; Ikemoto, A; Moriwaki, T; Nakamura, N; Miyaji, M; Zhang-Akiyama, Q-M

    2014-08-01

    Human oxidation resistance 1 (OXR1) functions in protection against oxidative damage and its homologs are highly conserved in eukaryotes examined so far, but its function still remains uncertain. In this study, we identified a homolog (LMD-3) of human OXR1 in the nematode Caenorhabditis elegans (C. elegans). The expressed LMD-3 was able to suppress the mutator phenotypes of E. coli mutMmutY and mutT mutants. Purified LMD-3 did not have enzymatic activity against 8-oxoG, superoxide dismutase (SOD), or catalase activities. Interestingly, the expression of LMD-3 was able to suppress the methyl viologen or menadione sodium bisulfite-induced expression of soxS and sodA genes in E. coli. The sensitivity of the C. elegans lmd-3 mutant to oxidative and heat stress was markedly higher than that of the wild-type strain N2. These results suggest that LMD-3 protects cells against oxidative stress. Furthermore, we found that the lifespan of the C. elegans lmd-3 mutant was significantly reduced compared with that of the N2, which was resulted from the acceleration of aging. We further examined the effects of deletions in other oxidative defense genes on the properties of the lmd-3 mutant. The deletion of sod-2 and sod-3, which are mitochondrial SODs, extended the lifespan of the lmd-3 mutant. These results indicate that, in cooperation with mitochondrial SODs, LMD-3 contributes to the protection against oxidative stress and aging in C. elegans.

  15. Age-Dependent Neuroendocrine Signaling from Sensory Neurons Modulates the Effect of Dietary Restriction on Longevity of Caenorhabditis elegans.

    Science.gov (United States)

    Fletcher, Marissa; Kim, Dennis H

    2017-01-01

    Dietary restriction extends lifespan in evolutionarily diverse animals. A role for the sensory nervous system in dietary restriction has been established in Drosophila and Caenorhabditis elegans, but little is known about how neuroendocrine signals influence the effects of dietary restriction on longevity. Here, we show that DAF-7/TGFβ, which is secreted from the C. elegans amphid, promotes lifespan extension in response to dietary restriction in C. elegans. DAF-7 produced by the ASI pair of sensory neurons acts on DAF-1/TGFβ receptors expressed on interneurons to inhibit the co-SMAD DAF-3. We find that increased activity of DAF-3 in the presence of diminished or deleted DAF-7 activity abrogates lifespan extension conferred by dietary restriction. We also observe that DAF-7 expression is dynamic during the lifespan of C. elegans, with a marked decrease in DAF-7 levels as animals age during adulthood. We show that this age-dependent diminished expression contributes to the reduced sensitivity of aging animals to the effects of dietary restriction. DAF-7 signaling is a pivotal regulator of metabolism and food-dependent behavior, and our studies establish a molecular link between the neuroendocrine physiology of C. elegans and the process by which dietary restriction can extend lifespan.

  16. The Intestinal Copper Exporter CUA-1 Is Required for Systemic Copper Homeostasis in Caenorhabditis elegans.

    Science.gov (United States)

    Chun, Haarin; Sharma, Anuj Kumar; Lee, Jaekwon; Chan, Jefferson; Jia, Shang; Kim, Byung-Eun

    2017-01-06

    Copper plays key catalytic and regulatory roles in biochemical processes essential for normal growth, development, and health. Defects in copper metabolism cause Menkes and Wilson's disease, myeloneuropathy, and cardiovascular disease and are associated with other pathophysiological states. Consequently, it is critical to understand the mechanisms by which organisms control the acquisition, distribution, and utilization of copper. The intestinal enterocyte is a key regulatory point for copper absorption into the body; however, the mechanisms by which intestinal cells transport copper to maintain organismal copper homeostasis are poorly understood. Here, we identify a mechanism by which organismal copper homeostasis is maintained by intestinal copper exporter trafficking that is coordinated with extraintestinal copper levels in Caenorhabditis elegans Specifically, we show that CUA-1, the C. elegans homolog of ATP7A/B, localizes to lysosome-like organelles (gut granules) in the intestine under copper overload conditions for copper detoxification, whereas copper deficiency results in a redistribution of CUA-1 to basolateral membranes for copper efflux to peripheral tissues. Worms defective in gut granule biogenesis exhibit defects in copper sequestration and increased susceptibility to toxic copper levels. Interestingly, however, a splice isoform CUA-1.2 that lacks a portion of the N-terminal domain is targeted constitutively to the basolateral membrane irrespective of dietary copper concentration. Our studies establish that CUA-1 is a key intestinal copper exporter and that its trafficking is regulated to maintain systemic copper homeostasis. C. elegans could therefore be exploited as a whole-animal model system to study regulation of intra- and intercellular copper trafficking pathways. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Dynamic energy-based modeling of uranium and cadmium joint toxicity to Caenorhabditis elegans.

    Science.gov (United States)

    Margerit, Adrien; Gomez, Elena; Gilbin, Rodolphe

    2016-03-01

    Toxicokinetic - toxicodynamic energy-based models offer new alternatives to the commonly used approaches for the analysis of mixture toxicity data. Based on the Dynamic Energy Budget theory, DEBtox models enable the description of several endpoints over time simultaneously under the same framework. However, such model still has to be faced with experimental data in a multi-contamination context. In this study, the predictive capacities of a DEBtox model to describe the uranium and cadmium joint toxicity over the entire growth and reproduction period of the soil nematode Caenorhabditis elegans was examined. The two reference additivity approaches, Concentration Addition and Response addition, implemented in the DEBtox model were tested. Assuming no interaction between the two toxicants through Response addition, the DEBtox model allowed a rather accurate fit of the U and Cd joint effects on the growth and reproduction of C. elegans: an interaction between the two metals at the toxicokinetic or toxicodynamic level seems thus unlikely or has only minor consequences. Interestingly, this study underlines that even if the compounds of a mixture share the same DEBtox physiological mode of action (in this case a decrease in assimilation), the Response addition approach may provide a better fit of joint toxicity data than the Concentration addition approach. Moreover, the present work highlighted limitations in the model predictions which are related to the simplifications of the DEBtox framework and its adaptations to the physiology of C. elegans and which lead to an overestimation of the U and Cd joint toxicity in some cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Alternative Polyadenylation Directs Tissue-Specific miRNA Targeting in Caenorhabditis elegans Somatic Tissues.

    Science.gov (United States)

    Blazie, Stephen M; Geissel, Heather C; Wilky, Henry; Joshi, Rajan; Newbern, Jason; Mangone, Marco

    2017-06-01

    mRNA expression dynamics promote and maintain the identity of somatic tissues in living organisms; however, their impact in post-transcriptional gene regulation in these processes is not fully understood. Here, we applied the PAT-Seq approach to systematically isolate, sequence, and map tissue-specific mRNA from five highly studied Caenorhabditis elegans somatic tissues: GABAergic and NMDA neurons, arcade and intestinal valve cells, seam cells, and hypodermal tissues, and studied their mRNA expression dynamics. The integration of these datasets with previously profiled transcriptomes of intestine, pharynx, and body muscle tissues, precisely assigns tissue-specific expression dynamics for 60% of all annotated C. elegans protein-coding genes, providing an important resource for the scientific community. The mapping of 15,956 unique high-quality tissue-specific polyA sites in all eight somatic tissues reveals extensive tissue-specific 3'untranslated region (3'UTR) isoform switching through alternative polyadenylation (APA) . Almost all ubiquitously transcribed genes use APA and harbor miRNA targets in their 3'UTRs, which are commonly lost in a tissue-specific manner, suggesting widespread usage of post-transcriptional gene regulation modulated through APA to fine tune tissue-specific protein expression. Within this pool, the human disease gene C. elegans orthologs rack-1 and tct-1 use APA to switch to shorter 3'UTR isoforms in order to evade miRNA regulation in the body muscle tissue, resulting in increased protein expression needed for proper body muscle function. Our results highlight a major positive regulatory role for APA, allowing genes to counteract miRNA regulation on a tissue-specific basis. Copyright © 2017 Blazie et al.

  19. An antidiabetic polyherbal phytomedicine confers stress resistance and extends lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Rathor, Laxmi; Pant, Aakanksha; Awasthi, Harshika; Mani, Dayanandan; Pandey, Rakesh

    2017-02-01

    An Ayurvedic polyherbal extract (PHE) comprising six herbs viz. Berberis aristata, Cyperus rotundus, Cedrus deodara, Emblica officinalis, Terminalia chebula and Terminalia bellirica is mentioned as an effective anti-hyperglycemic agent in 'Charaka Samhita', the classical text of Ayurveda. Previously, antidiabetic drug metformin was found to elicit antiaging effects and PHE was also found to exhibit antidiabetic effects in humans. Therefore, we screened it for its in vivo antioxidant antiaging effect on stress and lifespan using human homologous Caenorhabditis elegans model system. The effect on aging is evaluated by studying effect of PHE on mean survival in worms. The stress modulatory potential was assessed by quantification of intracellular ROS level, autofluorescent age pigment lipofuscin, oxidative and thermal stress assays. Additionally, stress response was quantified using gene reporter assays. The 0.01 µg/ml dose of PHE was able to enhance mean lifespan by 16.09% (P elegans. Furthermore, PHE treated worms demonstrated oxidative stress resistance in both wild type and stress hypersensitive mev-1 mutant along with upregulation of stress response genes sod-3 and gst-4. The delayed aging under stress can be attributed to its direct reactive oxygen species-scavenging activity and regulation of some age associated genes like daf-2, daf-16, skn-1, sod-3 and gst-4 in wild-type worms. Additonally, PHE delayed age related paralysis phenotype in CL4176 transgenic worms. Altogether, our results suggest PHE significantly improves the oxidative stress and life span in C. elegans. Overall the present study suggests this polyherbal formulation might play important role in regultaing aging and related complications like diabetes.

  20. A Marine Actinomycete Rescues Caenorhabditis elegans from Pseudomonas aeruginosa Infection through Restitution of Lysozyme 7

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    Siti N. Fatin

    2017-11-01

    Full Text Available The resistance of Pseudomonas aeruginosa to conventional antimicrobial treatment is a major scourge in healthcare. Therefore, it is crucial that novel potent anti-infectives are discovered. The aim of the present study is to screen marine actinomycetes for chemical entities capable of overcoming P. aeruginosa infection through mechanisms involving anti-virulence or host immunity activities. A total of 18 actinomycetes isolates were sampled from marine sediment of Songsong Island, Kedah, Malaysia. Upon confirming that the methanolic crude extract of these isolates do not display direct bactericidal activities, they were tested for capacity to rescue Caenorhabditis elegans infected with P. aeruginosa strain PA14. A hexane partition of the extract from one isolate, designated as Streptomyces sp. CCB-PSK207, could promote the survival of PA14 infected worms by more than 60%. Partial 16S sequence analysis on this isolate showed identity of 99.79% with Streptomyces sundarbansensis. This partition did not impair feeding behavior of C. elegans worms. Tested on PA14, the partition also did not affect bacterial growth or its ability to colonize host gut. The production of biofilm, protease, and pyocyanin in PA14 were uninterrupted, although there was an increase in elastase production. In lys-7::GFP worms, this partition was shown to induce the expression of lysozyme 7, an important innate immunity defense molecule that was repressed during PA14 infection. GC-MS analysis of the bioactive fraction of Streptomyces sp. CCB-PSK207 revealed the presence of methyl esters of branched saturated fatty acids. In conclusion, this is the first report of a marine actinomycete producing metabolites capable of rescuing C. elegans from PA14 through a lys-7 mediated activity.

  1. The Substrates of Nonsense-Mediated mRNA Decay in Caenorhabditis elegans

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    Virginia S. Muir

    2018-01-01

    Full Text Available Nonsense-mediated mRNA decay (NMD is a conserved pathway that strongly influences eukaryotic gene expression. Inactivating or inhibiting NMD affects the abundance of a substantial fraction of the transcriptome in numerous species. Transcripts whose abundance is altered in NMD-deficient cells may represent either direct substrates of NMD or indirect effects of inhibiting NMD. We present a genome-wide investigation of the direct substrates of NMD in Caenorhabditis elegans. Our goals were (i to identify mRNA substrates of NMD and (ii to distinguish those mRNAs from others whose abundance is indirectly influenced by the absence of NMD. We previously demonstrated that Upf1p/SMG-2, the central effector of NMD in all studied eukaryotes, preferentially associates with mRNAs that contain premature translation termination codons. We used this preferential association to distinguish direct from indirect effects by coupling immunopurification of Upf1/SMG-2 with high-throughput mRNA sequencing of NMD-deficient mutants and NMD-proficient controls. We identify 680 substrates of NMD, 171 of which contain novel spliced forms that (i include sequences of annotated introns and (ii have not been previously documented in the C. elegans transcriptome. NMD degrades unproductively spliced mRNAs with sufficient efficiency in NMD-proficient strains that such mRNAs were not previously known. Two classes of genes are enriched among the identified NMD substrates: (i mRNAs of expressed pseudogenes and (ii mRNAs of gene families whose gene number has recently expanded in the C. elegans genome. Our results identify novel NMD substrates and provide a context for understanding NMD’s role in normal gene expression and genome evolution.

  2. 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

  3. Effect of Bisphenol A on the Feeding Behavior of Caenorhabditis elegans

    OpenAIRE

    Kohra, Shinya; Kuwahara, Kazuko; Takao, Yuji; Ishibashi, Yasuhiro; Lee, Ho Chul; Arizono, Koji; Tominaga, Nobuaki

    2002-01-01

    We observed and evaluated the feeding behavior of the free-living nematode Caenorhabditis elegans (C. elegans) after exposure to bisphenol A (BPA) and nonylphenol (NP). Exposed organisms were transferred to chemical-free culture medium and their attainment levels (the number of worms reaching the food source divided by the total number of worms on the Petri plate) were recorded after 2, 4, 6, 8, and 24 hr. Results showed a significant decrease in the attainment level of worms exposed to 10 μM...

  4. 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

    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...... 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....

  5. The Effects of Erzincan Grape (Vitis vinifera spp., Cimin) and Benzothiazol on a Caenorhabditis elegans Organism Model.

    Science.gov (United States)

    Ozpinar, Hulya; Ozpinar, Necati; Karakus, Savas

    2017-07-01

    Grapes and their products are known to have been used for the treatment of diseases throughout history. It was aimed to investigate the effects of Erzincan Cimin grapes on an organism model of Caenorhabditis elegans N2 wild type and C. elegans BS913 strains with gonad cancer. The effects of methanol extracts of the skin and seeds of Erzincan Cimin grapes were examined separately on C. elegans N2 wild type and an effect was determined on lifespan. By applying GS-MS analysis, a potential agent substance was determined in the skin and seed methanol extracts. This substance was purchased and the effects of this substance were investigated on lifespan and fertility in C. elegans BS913 strains with gonad cancer. In addition, the effects on young subjects exposed to this agent substance in L1 form were investigated. Grape seed and skin methanol extract was observed to prolong the lifespan most at a dose of 10 mg/100 mL. Lifespan was determined to be at a maximum in a gonad cancer organism model with benzothiazol at a dose of 50 ppm. At the same dose, positive effects were determined on the fertility of strains with cancer. When the effects of benzothiazol were examined on young L1 forms, an evident retardation of growth was determined at doses of 10, 50, and 100 ppm. Owing to anti-carcinogenic effects of benzothiazol and benzothiazol-derived substances, they can be considered as agent substances in academic studies related to cancer. The effects of methanol extracts of the skin and seeds of Erzincan Cimin grapes were examined on C. elegans N2 wild type and an effect was determined on lifespanThrough GS-MS analysis, benzothiazol was determined in the skin methanol extractsBenzothiazol was purchased and the effects of this substance were investigated on lifespan and fertility in C. elegans BS913 strains with gonad cancerThe effects on young subjects exposed to benzothiazol in L1 formGrape seed, skin methanol extract, and benzothiazol was observed to prolong the lifespan

  6. The pore-forming protein Cry5B elicits the pathogenicity of Bacillus sp. against Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Melanie F Kho

    Full Text Available The soil bacterium Bacillus thuringiensis is a pathogen of insects and nematodes and is very closely related to, if not the same species as, Bacillus cereus and Bacillus anthracis. The defining characteristic of B. thuringiensis that sets it apart from B. cereus and B. anthracis is the production of crystal (Cry proteins, which are pore-forming toxins or pore-forming proteins (PFPs. Although it is known that PFPs are important virulence factors since their elimination results in reduced virulence of many pathogenic bacteria, the functions by which PFPs promote virulence are incompletely understood. Here we study the effect of Cry proteins in B. thuringiensis pathogenesis of the nematode Caenorhabditis elegans. We find that whereas B. thuringiensis on its own is not able to infect C. elegans, the addition of the PFP Cry protein, Cry5B, results in a robust lethal infection that consumes the nematode host in 1-2 days, leading to a "Bob" or bag-of-bacteria phenotype. Unlike other infections of C. elegans characterized to date, the infection by B. thuringiensis shows dose-dependency based on bacterial inoculum size and based on PFP concentration. Although the infection process takes 1-2 days, the PFP-instigated infection process is irreversibly established within 15 minutes of initial exposure. Remarkably, treatment of C. elegans with Cry5B PFP is able to instigate many other Bacillus species, including B. anthracis and even "non-pathogenic" Bacillus subtilis, to become lethal and infectious agents to C. elegans. Co-culturing of Cry5B-expressing B. thuringiensis with B. anthracis can result in lethal infection of C. elegans by B. anthracis. Our data demonstrate that one potential property of PFPs is to sensitize the host to bacterial infection and further that C. elegans and probably other roundworms can be common hosts for B. cereus-group bacteria, findings with important ecological and research implications.

  7. New Role for DCR-1/Dicer in Caenorhabditis elegans Innate Immunity against the Highly Virulent Bacterium Bacillus thuringiensis DB27

    OpenAIRE

    Iatsenko, Igor; Sinha, Amit; Rödelsperger, Christian; Sommer, Ralf J.

    2013-01-01

    Bacillus thuringiensis produces toxins that target invertebrates, including Caenorhabditis elegans. Virulence of Bacillus strains is often highly specific, such that B. thuringiensis strain DB27 is highly pathogenic to C. elegans but shows no virulence for another model nematode, Pristionchus pacificus. To uncover the underlying mechanisms of the differential responses of the two nematodes to B. thuringiensis DB27 and to reveal the C. elegans defense mechanisms against this pathogen, we condu...

  8. Contrasting responses within a single neuron class enable sex-specific attraction in Caenorhabditis elegans

    OpenAIRE

    Narayan, Anusha; Venkatachalam, Vivek; Durak, Omer; Reilly, Douglas K.; Bose, Neelanjan; Schroeder, Frank C.; Samuel, Aravinthan DT; Srinivasan, Jagan; Sternberg, Paul W.

    2016-01-01

    Animals find mates and food, and avoid predators, by navigating to regions within a favorable range of available sensory cues. How are these ranges set and recognized? Here we show that male Caenorhabditis elegans exhibit strong concentration preferences for sex-specific small molecule cues secreted by hermaphrodites, and that these preferences emerge from the collective dynamics of a single male-specific class of neurons, the cephalic sensory neurons (CEMs). Within a single worm, CEM respons...

  9. A Novel Dominant Transformer Allele of the Sex-Determining Gene Her-1 of Caenorhabditis Elegans

    OpenAIRE

    Trent, C.; Wood, W. B.; Horvitz, H. R.

    1988-01-01

    We have characterized a novel dominant allele of the sex-determining gene her-1 of Caenorhabditis elegans. This allele, called n695, results in the incomplete transformation of XX animals into phenotypic males. Previously characterized recessive her-1 alleles transform XO animals into phenotypic hermaphrodites. We have identified five new recessive her-1 mutations as intragenic suppressors of n695. Three of these suppressors are weak, temperature-sensitive alleles. We show that the recessive ...

  10. 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 ...... data suggest that DPY-18 regulates ephrin expression to direct axon guidance, a role for P4Hs that may be conserved in higher organisms....

  11. 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.

  12. Homologs of genes expressed in Caenorhabditis elegans GABAergic neurons are also found in the developing mouse forebrain

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    Earls Laurie R

    2010-12-01

    Full Text Available Abstract Background In an effort to identify genes that specify the mammalian forebrain, we used a comparative approach to identify mouse homologs of transcription factors expressed in developing Caenorhabditis elegans GABAergic neurons. A cell-specific microarray profiling study revealed a set of transcription factors that are highly expressed in embryonic C. elegans GABAergic neurons. Results Bioinformatic analyses identified mouse protein homologs of these selected transcripts and their expression pattern was mapped in the mouse embryonic forebrain by in situ hybridization. A review of human homologs indicates several of these genes are potential candidates in neurodevelopmental disorders. Conclusions Our comparative approach has revealed several novel candidates that may serve as future targets for studies of mammalian forebrain development.

  13. 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...

  14. A map of terminal regulators of neuronal identity in Caenorhabditis elegans

    Science.gov (United States)

    2016-01-01

    Our present day understanding of nervous system development is an amalgam of insights gained from studying different aspects and stages of nervous system development in a variety of invertebrate and vertebrate model systems, with each model system making its own distinctive set of contributions. One aspect of nervous system development that has been among the most extensively studied in the nematode Caenorhabditis elegans is the nature of the gene regulatory programs that specify hardwired, terminal cellular identities. I first summarize a number of maps (anatomical, functional, and molecular) that describe the terminal identity of individual neurons in the C. elegans nervous system. I then provide a comprehensive summary of regulatory factors that specify terminal identities in the nervous system, synthesizing these past studies into a regulatory map of cellular identities in the C. elegans nervous system. This map shows that for three quarters of all neurons in the C. elegans nervous system, regulatory factors that control terminal identity features are known. In‐depth studies of specific neuron types have revealed that regulatory factors rarely act alone, but rather act cooperatively in neuron‐type specific combinations. In most cases examined so far, distinct, biochemically unlinked terminal identity features are coregulated via cooperatively acting transcription factors, termed terminal selectors, but there are also cases in which distinct identity features are controlled in a piecemeal fashion by independent regulatory inputs. The regulatory map also illustrates that identity‐defining transcription factors are reemployed in distinct combinations in different neuron types. However, the same transcription factor can drive terminal differentiation in neurons that are unrelated by lineage, unrelated by function, connectivity and neurotransmitter deployment. Lastly, the regulatory map illustrates the preponderance of homeodomain transcription factors in the

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

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    Fatma Kaplan

    2011-03-01

    Full Text Available 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.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.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 pathways that control ascaroside biosynthesis. In conjunction with findings

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

    Science.gov (United States)

    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.

  17. Comparative Analysis of Stress Induced Gene Expression in Caenorhabditis elegans following Exposure to Environmental and Lab Reconstituted Complex Metal Mixture.

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    Ranjeet Kumar

    Full Text Available Metals are essential for many physiological processes and are ubiquitously present in the environment. However, high metal concentrations can be harmful to organisms and lead to physiological stress and diseases. The accumulation of transition metals in the environment due to either natural processes or anthropogenic activities such as mining results in the contamination of water and soil environments. The present study used Caenorhabditis elegans to evaluate gene expression as an indicator of physiological response, following exposure to water collected from three different locations downstream of a Swedish mining site and a lab reconstituted metal mixture. Our results indicated that the reconstituted metal mixture exerted a direct stress response in C. elegans whereas the environmental waters elicited either a diminished or abrogated response. This suggests that it is not sufficient to use the biological effects observed from laboratory mixtures to extrapolate the effects observed in complex aquatic environments and apply this to risk assessment and intervention.

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

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    Yoko Honda

    Full Text Available 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.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.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 species and may lead to the development of nutraceutical

  19. Phase-dependent preference of thermosensation and chemosensation during simultaneous presentation assay in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Shingai Ryuzo

    2008-11-01

    Full Text Available Abstract Background Multi-sensory integration is necessary for organisms to discriminate different environmental stimuli and thus determine behavior. Caenorhabditis elegans has 12 pairs of amphid sensory neurons, which are involved in generating behaviors such as thermotaxis toward cultivation temperature, and chemotaxis toward chemical stimuli. This arrangement of known sensory neurons and measurable behavioral output makes C. elegans suitable for addressing questions of multi-sensory integration in the nervous system. Previous studies have suggested that C. elegans can process different chemoattractants simultaneously. However, little is known about how these organisms can integrate information from stimuli of different modality, such as thermal and chemical stimuli. Results We studied the behavior of a population of C. elegans during simultaneous presentation of thermal and chemical stimuli. First, we examined thermotaxis within the radial temperature gradient produced by a feedback-controlled thermoregulator. Separately, we examined chemotaxis toward sodium chloride or isoamyl alcohol. Then, assays for simultaneous presentations of 15°C (colder temperature than 20°C room temperature and chemoattractant were performed with 15°C-cultivated wild-type worms. Unlike the sum of behavioral indices for each separate behavior, simultaneous presentation resulted in a biased migration to cold regions in the first 10 min of the assay, and sodium chloride-regions in the last 40 min. However, when sodium chloride was replaced with isoamyl alcohol in the simultaneous presentation, the behavioral index was very similar to the sum of separate single presentation indices. We then recorded tracks of single worms and analyzed their behavior. For behavior toward sodium chloride, frequencies of forward and backward movements in simultaneous presentation were significantly different from those in single presentation. Also, migration toward 15°C in simultaneous

  20. Inhibition of Fat Accumulation by Hesperidin in Caenorhabditis elegans.

    Science.gov (United States)

    Peng, Huimin; Wei, Zhaohan; Luo, Hujie; Yang, Yiting; Wu, Zhengxing; Gan, Lu; Yang, Xiangliang

    2016-06-29

    Hesperidin, abundant in citrus fruits, has a wide range of pharmacological effects, including anticarcinogenic, anti-inflammatory, antioxidative, radioprotective, and antiviral activities. However, relatively few studies on the effects of hesperidin on lipid metabolism have been reported. Here, using Caenorhaditis elegans as a model animal, we found that 100 μM hesperidin significantly decreased fat accumulation in both high-fat worms cultured in nematode growth medium containing 10 mM glucose (83.5 ± 1.2% versus control by Sudan Black B staining and 87.6 ± 2.0% versus control by Oil Red O staining; p hesperidin decreased the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) (p hesperidin on fat accumulation. Hesperidin significantly downregulated the expression of stearoyl-CoA desaturase, fat-6, and fat-7 (p hesperidin. In addition, hesperidin decreased the expression of other genes involved in lipid metabolism, including pod-2, mdt-15, acs-2, and kat-1 (p hesperidin reduced fat accumulation by affecting several lipid metabolism pathways, such as fat-6 and fat-7. This study provided new insights into elucidating the mechanism underlying the regulation of lipid metabolism by hesperidin.

  1. Optogenetics and computer vision for Caenorhabditis elegans neuroscience and other biophysical applications

    Science.gov (United States)

    Leifer, Andrew Michael

    2011-07-01

    This work presents optogenetics and real-time computer vision techniques to non-invasively manipulate and monitor neural activity with high spatiotemporal resolution in awake behaving Caenorhabditis elegans. These methods were employed to dissect the nematode's mechanosensory and motor circuits and to elucidate the neural control of wave propagation during forward locomotion. Additionally, similar computer vision methods were used to automatically detect and decode fluorescing DNA origami nanobarcodes, a new class of fluorescent reporter constructs. An optogenetic instrument capable of real-time light delivery with high spatiotemporal resolution to specified targets in freely moving C. elegans, the first such instrument of its kind, was developed. The instrument was used to probe the nematode's mechanosensory circuit, demonstrating that stimulation of a single mechanosensory neuron suffices to induce reversals. The instrument was also used to probe the motor circuit, demonstrating that inhibition of regions of cholinergic motor neurons blocks undulatory wave propagation and that muscle contractions can persist even without inputs from the motor neurons. The motor circuit was further probed using optogenetics and microfluidic techniques. Undulatory wave propagation during forward locomotion was observed to depend on stretch-sensitive signaling mediated by cholinergic motor neurons. Specifically, posterior body segments are compelled, through stretch-sensitive feedback, to bend in the same direction as anterior segments. This is the first explicit demonstration of such feedback and serves as a foundation for understanding motor circuits in other organisms. A real-time tracking system was developed to record intracellular calcium transients in single neurons while simultaneously monitoring macroscopic behavior of freely moving C. elegans. This was used to study the worm's stereotyped reversal behavior, the omega turn. Calcium transients corresponding to temporal

  2. 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.

  3. The Remarkably Diverse Family of T-Box Factors in Caenorhabditis elegans.

    Science.gov (United States)

    Okkema, P G

    2017-01-01

    The nematode Caenorhabditis elegans is a simple metazoan animal that is widely used as a model to understand the genetic control of development. The completely sequenced C. elegans genome contains 22 T-box genes, and they encode factors that show remarkable diversity in sequence, DNA-binding specificity, and function. Only three of the C. elegans T-box factors can be grouped into the conserved subfamilies found in other organisms, while the remaining factors are significantly diverged and unlike those in most other animals. While some of the C. elegans factors can bind canonical T-box binding elements, others bind and regulate target gene expression through distinct sequences. The nine genetically characterized T-box factors have varied functions in development and morphogenesis of muscle, hypodermal tissues, and neurons, as well as in early blastomere fate specification, cell migration, apoptosis, and sex determination, but the functions of most of the C. elegans T-box factors have not yet been extensively characterized. Like T-box factors in other animals, interaction with a Groucho-family corepressor and posttranslational SUMOylation have been shown to affect C. elegans T-box factor activity, and it is likely that additional mechanisms affecting T-box factor activity will be discovered using the effective genetic approaches in this organism. © 2017 Elsevier Inc. All rights reserved.

  4. Topological cluster analysis reveals the systemic organization of the Caenorhabditis elegans connectome.

    Directory of Open Access Journals (Sweden)

    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.

  5. 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

  6. Anti-Parkinsonian effects of β-amyrin are regulated via LGG-1 involved autophagy pathway in Caenorhabditis elegans.

    Science.gov (United States)

    Wei, Chia-Cheng; Chang, Chun-Han; Liao, Vivian Hsiu-Chuan

    2017-12-01

    Parkinson's disease (PD) is a neurodegenerative disease that is associated with aging and is characterized as a movement disorder. Currently, there is still no complete therapy for PD. In recent years, the identification and characterization of medicinal plants to cure or treat PD has gained increasing scientific interest. In this study, we investigated a pentacyclic triterpenoid compound, β-amyrin, which is found in many medicinal plants for its anti-Parkinsonian effects, using Caenorhabditis elegans (C. elegans) disease models and their underlying mechanisms. C. elegans treated or untreated with β-amyrin were investigated for oxidative stress resistance, neurodegeneration, and α-synuclein aggregation assays. The C. elegans ortholog of Atg8/LC3, LGG-1 that is involved in the autophagy pathway was also evaluated by quantitative RT-PCR and transgenic strain experiments. β-Amyrin exerted excellent antioxidant activity and reduced intracellular oxygen species in C. elegans. Using the transgenic strain BZ555, β-amyrin showed a protective effect on dopaminergic neurons reducing cell damage induced by 6-hydroxydopamine (6-OHDA). In addition, β-amyrin significantly reduced the α-synuclein aggregation in the transgenic strain NL5901. Moreover, β-amyrin up-regulated LGG-1 mRNA expression and increased the number of localized LGG-1 puncta in the transgenic strain DA2123. The results from this study suggest that the anti-Parkinsonian effects of β-amyrin might be regulated via LGG-1 involved autophagy pathway in C. elegans. Therefore, β-amyrin may be useful for therapeutic applications or supplements to treat or slow the progression of PD. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. A Large Collection of Novel Nematode-Infecting Microsporidia and Their Diverse Interactions with Caenorhabditis elegans and Other Related Nematodes

    Science.gov (United States)

    Zhang, Gaotian; Sachse, Martin; Prevost, Marie-Christine; Troemel, Emily R.; Félix, Marie-Anne

    2016-01-01

    Microsporidia are fungi-related intracellular pathogens that may infect virtually all animals, but are poorly understood. The nematode Caenorhabditis elegans has recently become a model host for studying microsporidia through the identification of its natural microsporidian pathogen Nematocida parisii. However, it was unclear how widespread and diverse microsporidia infections are in C. elegans or other related nematodes in the wild. Here we describe the isolation and culture of 47 nematodes with microsporidian infections. N. parisii is found to be the most common microsporidia infecting C. elegans in the wild. In addition, we further describe and name six new species in the Nematocida genus. Our sampling and phylogenetic analysis further identify two subclades that are genetically distinct from Nematocida, and we name them Enteropsectra and Pancytospora. Interestingly, unlike Nematocida, these two genera belong to the main clade of microsporidia that includes human pathogens. All of these microsporidia are horizontally transmitted and most specifically infect intestinal cells, except Pancytospora epiphaga that replicates mostly in the epidermis of its Caenorhabditis host. At the subcellular level in the infected host cell, spores of the novel genus Enteropsectra show a characteristic apical distribution and exit via budding off of the plasma membrane, instead of exiting via exocytosis as spores of Nematocida. Host specificity is broad for some microsporidia, narrow for others: indeed, some microsporidia can infect Oscheius tipulae but not its sister species Oscheius sp. 3, and conversely some microsporidia found infecting Oscheius sp. 3 do not infect O. tipulae. We also show that N. ausubeli fails to strongly induce in C. elegans the transcription of genes that are induced by other Nematocida species, suggesting it has evolved mechanisms to prevent induction of this host response. Altogether, these newly isolated species illustrate the diversity and ubiquity of

  8. The nematode Caenorhabditis elegans, stress and aging: Identifying the complex interplay of genetic pathways following the treatment with humic substances

    Directory of Open Access Journals (Sweden)

    Ralph eMenzel

    2012-04-01

    Full Text Available Low concentrations of the dissolved leonardite humic acid HuminFeed® (HF prolonged the lifespan and enhanced the thermal stress resistance of the model organism Caenorhabditis elegans. However, growth was impaired and reproduction delayed, effects which have also been identified in response to other polyphenolic monomers, including Tannic acid, Rosmarinic acid, and Caffeic acid. Moreover, a chemical modification of HF, which increases its phenolic/quinonoid moieties, magnified the biological impact on C. elegans. To gain a deep insight into the molecular basis of these effects, we performed global transcriptomics on young adult (3 d and old adult (11 d nematodes exposed to two different concentrations of HF. We also studied several C. elegans mutant strains in respect to HF derived longevity and compared all results with data obtained for the chemically modified HF. The gene expression pattern of young HF treated nematodes displayed a significant overlap to other conditions known to provoke longevity, including various plant polyphenol monomers. Besides the regulation of parts of the metabolism, TGF- signaling and Insulin-like signaling, lysosomal activities seem to contribute most to HF’s and modified HF’s lifespan prolonging action. These results support the notion that the phenolic/quinonoid moieties of humic substances are major building blocks that drive the physiological effects observed in C. elegans.

  9. Peptides from sesame cake extend healthspan of Caenorhabditis elegans via upregulation of skn-1 and inhibition of intracellular ROS levels.

    Science.gov (United States)

    Wang, Zhuanhua; Ma, Xiaoli; Li, Jiao; Cui, Xiaodong

    2016-09-01

    The peptides from sesame cake (PSC) which are the main by-product of agricultural processing of sesame were prepared. To evaluate benefits of PSC for health and longevity, antioxidant activity and anti-aging effects were studied in vitro and in a Caenorhabditis elegans (C. elegans) model system. PSC exhibited antioxidant activity in vitro, and induced beneficial effects on lifespan and several health parameters of C.elegans, including pharyngeal pumping rate, locomotion and lipofuscin accumulation. In a mev-1 mutant, PSC increased lifespan, and it enhanced oxidative stress tolerance in wild-type nematodes. After treatment with PSC, SOD activity, GSH content, and GSH/GSSG ratio were increased, leading to low intracellular ROS levels in C. elegans. PSC up-regulated skn-1 mRNA, and its target gene gcs-1, and abolished the extension of lifespan in skn-1 mutant, indicating that PSC-mediated longevity is dependent on activation of the skn-1/Nrf-2 transcription factor. Current results warrant research into the use of PSC as nutraceuticals for overall health improvement. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Putative calcium-binding domains of the Caenorhabditis elegans BK channel are dispensable for intoxication and ethanol activation

    Science.gov (United States)

    Davis, S. J.; Scott, L. L.; Ordemann, G.; Philpo, A.; Cohn, J.; Pierce-Shimomura, J. T.

    2016-01-01

    Alcohol modulates the highly conserved, voltage- and calcium-activated potassium (BK) channel, which contributes to alcohol-mediated behaviors in species from worms to humans. Previous studies have shown that the calcium-sensitive domains, RCK1 and the Ca2+ bowl, are required for ethanol activation of the mammalian BK channel in vitro. In the nematode Caenorhabditis elegans, ethanol activates the BK channel in vivo, and deletion of the worm BK channel, SLO-1, confers strong resistance to intoxication. To determine if the conserved RCK1 and calcium bowl domains were also critical for intoxication and basal BK channel-dependent behaviors in C. elegans, we generated transgenic worms that express mutated SLO-1 channels predicted to have the RCK1, Ca2+ bowl or both domains rendered insensitive to calcium. As expected, mutating these domains inhibited basal function of SLO-1 in vivo as neck and body curvature of these mutants mimicked that of the BK null mutant. Unexpectedly, however, mutating these domains singly or together in SLO-1 had no effect on intoxication in C. elegans. Consistent with these behavioral results, we found that ethanol activated the SLO-1 channel in vitro with or without these domains. By contrast, in agreement with previous in vitro findings, C. elegans harboring a human BK channel with mutated calcium-sensing domains displayed resistance to intoxication. Thus, for the worm SLO-1 channel, the putative calcium-sensitive domains are critical for basal in vivo function but unnecessary for in vivo ethanol action. PMID:26113050

  11. Caenorhabditis elegans syndecan (SDN-1) is required for normal egg laying and associates with the nervous system and the vulva.

    Science.gov (United States)

    Minniti, Alicia N; Labarca, Mariana; Hurtado, Claudia; Brandan, Enrique

    2004-10-01

    In Caenorhabditis elegans, the identification of many enzymes involved in the synthesis and modification of glycosaminoglycans (GAGs), essential components of proteoglycans, has attained special attention in recent years. Mutations in all the genes that encode for GAG biosynthetic enzymes show defects in the development of the vulva, specifically in the invagination of the vulval epithelium. Mutants for certain heparan sulfate modifying enzymes present axonal and cellular guidance defects in specific neuronal classes. Although most of the enzymes involved in the biosynthesis and modification of heparan sulfate have been characterized in C. elegans, little is known regarding the core proteins to which these GAGs covalently bind in proteoglycans. A single syndecan homologue (sdn-1) has been identified in the C. elegans genome through sequence analysis. In the present study, we show that C. elegans synthesizes sulfated proteoglycans, seen as three distinct species in western blot analysis. In the sdn-1 (ok449) deletion mutant allele we observed the lack of one species, which corresponds to a 50 kDa product after heparitinase treatment. The expression of sdn-1 mRNA and sequencing revealed that sdn-1 (ok449) deletion mutants lack two glycosylation sites. Hence, the missing protein in the western blot analysis probably corresponds to SDN-1. In addition, we show that SDN-1 localizes to the C. elegans nerve ring, nerve cords and to the vulva. SDN-1 is found specifically phosphorylated in nerve ring neurons and in the vulva, in both wild-type worms and sdn-1 (ok449) deletion mutants. These mutants show a defective egg-laying phenotype. Our results show for the first time, the identification, localization and some functional aspects of syndecan in the nematode C. elegans.

  12. Glucose-rich diet aggravates monocrotophos-induced dopaminergic neuronal dysfunction in Caenorhabditis elegans.

    Science.gov (United States)

    Salim, Chinnu; Rajini, P S

    2017-06-01

    The present study aimed to obtain insights into the mechanism(s) by which glucose-rich diet aggravates monocrotophos (MCP)-induced dopaminergic neuronal dysfunction in Caenorhabditis elegans. In this study, we exposed three different strains of worms (wild-type N2, CB1112 (cat-2(e1112)II, tyrosine hydroxylase-deficient mutant, catecholamine absent) and the transgenic BZ555 (egls1-dat-1p::green fluorescent protein [GFP]) (in which bright GFP is tagged to the dopamine neuronal soma and processes) grown and maintained in normal nematode growth medium or 2% glucose enriched-nematode growth medium to MCP (0.75 mm) for 48 h. After the exposure, dopamine-mediated behaviors such as repulsion to nonanone, chemotaxis index and basal slowing response were determined in worms. Dopamine, 3,4-dihydroxy phenyl acetic acid and homovanillic acid content were quantified in N2 worms. The extent of neurodegeneration was visualized and quantified in dat-1::GFP worms. Basal slowing response study clearly indicated that cat-2 worms exposed to MCP and glucose were less affected compared to N2 of the same treatment. Learning and memory were affected by MCP and glucose. While MCP-treated worms showed lesser repulsion to nonanone compared to control worms, MCP-treated, glucose-fed worms showed a greater reduction in repulsion to nonanone. Further, MCP-treated, glucose-fed worms exhibited a marked reduction in dopamine content and an increase in 3,4-dihydroxy phenyl acetic acid and homovanillic acid levels compared to that in control. Dat-1::GFP showed a significant degeneration of dopaminergic neurons when exposed to glucose and MCP. Thus, our results clearly demonstrate that glucose-rich diet aggravates the dopaminergic neuronal dysfunction induced by MCP in C. elegans. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Bisphenol A exposure accelerated the aging process in the nematode Caenorhabditis elegans.

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    Tan, Ling; Wang, Shunchang; Wang, Yun; He, Mei; Liu, Dahai

    2015-06-01

    Bisphenol A (BPA) is a well-known environmental estrogenic disruptor that causes adverse effects. Recent studies have found that chronic exposure to BPA is associated with a high incidence of several age-related diseases. Aging is characterized by progressive function decline, which affects quality of life. However, the effects of BPA on the aging process are largely unknown. In the present study, by using the nematode Caenorhabditis elegans as a model, we investigated the influence of BPA exposure on the aging process. The decrease in body length, fecundity, and population size and the increased egg laying defection suggested that BPA exposure resulted in fitness loss and reproduction aging in this animal. Lifetime exposure of worms to BPA shortened the lifespan in a dose-dependant manner. Moreover, prolonged BPA exposure resulted in age-related behavior degeneration and the accumulation of lipofuscin and lipid peroxide products. The expression of mitochondria-specific HSP-6 and endoplasmic reticulum (ER)-related HSP-70 exhibited hormetic decrease. The expression of ER-related HSP-4 decreased significantly while HSP-16.2 showed a dose-dependent increase. The decreased expression of GCS-1 and GST-4 implicated the reduced antioxidant ability under BPA exposure, and the increase in SOD-3 expression might be caused by elevated levels of reactive oxygen species (ROS) production. Finally, BPA exposure increased the generation of hydrogen peroxide-related ROS and superoxide anions. Our results suggest that BPA exposure resulted in an accelerated aging process in C. elegans mediated by the induction of oxidative stress. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Antagonistic Serotonergic and Octopaminergic Neural Circuits Mediate Food-Dependent Locomotory Behavior in Caenorhabditis elegans.

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    Churgin, Matthew A; McCloskey, Richard J; Peters, Emily; Fang-Yen, Christopher

    2017-08-16

    Biogenic amines are conserved signaling molecules that link food cues to behavior and metabolism in a wide variety of organisms. In the nematode Caenorhabditis elegans, the biogenic amines serotonin (5-HT) and octopamine regulate a number of food-related behaviors. Using a novel method for long-term quantitative behavioral imaging, we show that 5-HT and octopamine jointly influence locomotor activity and quiescence in feeding and fasting hermaphrodites, and we define the neural circuits through which this modulation occurs. We show that 5-HT produced by the ADF neurons acts via the SER-5 receptor in muscles and neurons to suppress quiescent behavior and promote roaming in fasting worms, whereas 5-HT produced by the NSM neurons acts on the MOD-1 receptor in AIY neurons to promote low-amplitude locomotor behavior characteristic of well fed animals. Octopamine, produced by the RIC neurons, acts via SER-3 and SER-6 receptors in SIA neurons to promote roaming behaviors characteristic of fasting animals. We find that 5-HT signaling is required for animals to assume food-appropriate behavior, whereas octopamine signaling is required for animals to assume fasting-appropriate behavior. The requirement for both neurotransmitters in both the feeding and fasting states enables increased behavioral adaptability. Our results define the molecular and neural pathways through which parallel biogenic amine signaling tunes behavior appropriately to nutrient conditions.SIGNIFICANCE STATEMENT Animals adjust behavior in response to environmental changes, such as fluctuations in food abundance, to maximize survival and reproduction. Biogenic amines, such as like serotonin, are conserved neurotransmitters that regulate behavior and metabolism in relation to energy status. Disruptions of biogenic amine signaling contribute to human neurological diseases of mood, appetite, and movement. In this study, we investigated the roles of the biogenic amines serotonin and octopamine in regulating

  15. Compartmentalized cGMP Responses of Olfactory Sensory Neurons inCaenorhabditis elegans.

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    Shidara, Hisashi; Hotta, Kohji; Oka, Kotaro

    2017-04-05

    Cyclic guanosine monophosphate (cGMP) plays a crucial role as a second messenger in the regulation of sensory signal transduction in many organisms. In AWC olfactory sensory neurons of Caenorhabditis elegans , cGMP also has essential and distinctive functions in olfactory sensation and adaptation. According to molecular genetic studies, when nematodes are exposed to odorants, a decrease in cGMP regulates cGMP-gated channels for olfactory sensation. Conversely, for olfactory adaptation, an increase in cGMP activates protein kinase G to modulate cellular physiological functions. Although these opposing cGMP responses in single neurons may occur at the same time, it is unclear how cGMP actually behaves in AWC sensory neurons. A hypothetical explanation for opposing cGMP responses is region-specific behaviors in AWC: for odor sensation, cGMP levels in cilia could decrease, whereas odor adaptation is mediated by increased cGMP levels in soma. Therefore, we visualized intracellular cGMP in AWC with a genetically encoded cGMP indicator, cGi500, and examined spatiotemporal cGMP responses in AWC neurons. The cGMP imaging showed that, after odor exposure, cGMP levels in AWC cilia decreased transiently, whereas levels in dendrites and soma gradually increased. These region-specific responses indicated that the cGMP responses in AWC neurons are explicitly compartmentalized. In addition, we performed Ca 2+ imaging to examine the relationship between cGMP and Ca 2+ These results suggested that AWC sensory neurons are in fact analogous to vertebrate photoreceptor neurons. SIGNIFICANCE STATEMENT Cyclic guanosine monophosphate (cGMP) plays crucial roles in the regulation of sensory signal transduction in many animals. In AWC olfactory sensory neurons of Caenorhabditis elegans , cGMP also has essential and distinctive functions involving olfactory sensation and adaptation. Here, we visualized intracellular cGMP in AWC neurons with a genetically encoded cGMP indicator and examined

  16. UNC-18 and Tomosyn Antagonistically Control Synaptic Vesicle Priming Downstream of UNC-13 in Caenorhabditis elegans.

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    Park, Seungmee; Bin, Na-Ryum; Yu, Bin; Wong, Raymond; Sitarska, Ewa; Sugita, Kyoko; Ma, Ke; Xu, Junjie; Tien, Chi-Wei; Algouneh, Arash; Turlova, Ekaterina; Wang, Siyan; Siriya, Pranay; Shahid, Waleed; Kalia, Lorraine; Feng, Zhong-Ping; Monnier, Philippe P; Sun, Hong-Shuo; Zhen, Mei; Gao, Shangbang; Rizo, Josep; Sugita, Shuzo

    2017-09-06

    Munc18-1/UNC-18 is believed to prime SNARE-mediated membrane fusion, yet the underlying mechanisms remain enigmatic. Here, we examine how potential gain-of-function mutations of Munc18-1/UNC-18 affect locomotory behavior and synaptic transmission, and how Munc18-1-mediated priming is related to Munc13-1/UNC-13 and Tomosyn/TOM-1, positive and negative SNARE regulators, respectively. We show that a Munc18-1(P335A)/UNC-18(P334A) mutation leads to significantly increased locomotory activity and acetylcholine release in Caenorhabditis elegans, as well as enhanced synaptic neurotransmission in cultured mammalian neurons. Importantly, similar to tom-1 null mutants, unc-18(P334A) mutants partially bypass the requirement of UNC-13. Moreover, unc-18(P334A) and tom-1 null mutations confer a strong synergy in suppressing the phenotypes of unc-13 mutants. Through biochemical experiments, we demonstrate that Munc18-1(P335A) exhibits enhanced activity in SNARE complex formation as well as in binding to the preformed SNARE complex, and partially bypasses the Munc13-1 requirement in liposome fusion assays. Our results indicate that Munc18-1/UNC-18 primes vesicle fusion downstream of Munc13-1/UNC-13 by templating SNARE complex assembly and acts antagonistically with Tomosyn/TOM-1.SIGNIFICANCE STATEMENT At presynaptic sites, SNARE-mediated membrane fusion is tightly regulated by several key proteins including Munc18/UNC-18, Munc13/UNC-13, and Tomosyn/TOM-1. However, how these proteins interact with each other to achieve the precise regulation of neurotransmitter release remains largely unclear. Using Caenorhabditis elegans as an in vivo model, we found that a gain-of-function mutant of UNC-18 increases locomotory activity and synaptic acetylcholine release, that it partially bypasses the requirement of UNC-13 for release, and that this bypass is synergistically augmented by the lack of TOM-1. We also elucidated the biochemical basis for the gain-of-function caused by this mutation

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

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    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.

  18. Involvement of heat shock proteins on Mn-induced toxicity in Caenorhabditis elegans.

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    Avila, Daiana Silva; Benedetto, Alexandre; Au, Catherine; Bornhorst, Julia; Aschner, Michael

    2016-11-02

    All living cells display a rapid molecular response to adverse environmental conditions, and the heat shock protein family reflects one such example. Hence, failing to activate heat shock proteins can impair the cellular response. In the present study, we evaluated whether the loss of different isoforms of heat shock protein (hsp) genes in Caenorhabditis elegans would affect their vulnerability to Manganese (Mn) toxicity. We exposed wild type and selected hsp mutant worms to Mn (30 min) and next evaluated further the most susceptible strains. We analyzed survival, protein carbonylation (as a marker of oxidative stress) and Parkinson's disease related gene expression immediately after Mn exposure. Lastly, we observed dopaminergic neurons in wild type worms and in hsp-70 mutants following Mn treatment. Analysis of the data was performed by one-way or two way ANOVA, depending on the case, followed by post-hoc Bonferroni test if the overall p value was less than 0.05. We verified that the loss of hsp-70, hsp-3 and chn-1 increased the vulnerability to Mn, as exposed mutant worms showed lower survival rate and increased protein oxidation. The importance of hsp-70 against Mn toxicity was then corroborated in dopaminergic neurons, where Mn neurotoxicity was aggravated. The lack of hsp-70 also blocked the transcriptional upregulation of pink1, a gene that has been linked to Parkinson's disease. Taken together, our data suggest that Mn exposure modulates heat shock protein expression, particularly HSP-70, in C. elegans. Furthermore, loss of hsp-70 increases protein oxidation and dopaminergic neuronal degeneration following manganese exposure, which is associated with the inhibition of pink1 increased expression, thus potentially exacerbating the vulnerability to this metal.

  19. Evaluation of head movement periodicity and irregularity during locomotion of Caenorhabditis elegans

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    Ryuzo eShingai

    2013-03-01

    Full Text Available Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx or 50% (the mid-body point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.

  20. Filamin and phospholipase C-ε are required for calcium signaling in the Caenorhabditis elegans spermatheca.

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    Ismar Kovacevic

    2013-05-01

    Full Text Available The Caenorhabditis elegans spermatheca is a myoepithelial tube that stores sperm and undergoes cycles of stretching and constriction as oocytes enter, are fertilized, and exit into the uterus. FLN-1/filamin, a stretch-sensitive structural and signaling scaffold, and PLC-1/phospholipase C-ε, an enzyme that generates the second messenger IP3, are required for embryos to exit normally after fertilization. Using GCaMP, a genetically encoded calcium indicator, we show that entry of an oocyte into the spermatheca initiates a distinctive series of IP3-dependent calcium oscillations that propagate across the tissue via gap junctions and lead to constriction of the spermatheca. PLC-1 is required for the calcium release mechanism triggered by oocyte entry, and FLN-1 is required for timely initiation of the calcium oscillations. INX-12, a gap junction subunit, coordinates propagation of the calcium transients across the spermatheca. Gain-of-function mutations in ITR-1/IP3R, an IP3-dependent calcium channel, and loss-of-function mutations in LFE-2, a negative regulator of IP3 signaling, increase calcium release and suppress the exit defect in filamin-deficient animals. We further demonstrate that a regulatory cassette consisting of MEL-11/myosin phosphatase and NMY-1/non-muscle myosin is required for coordinated contraction of the spermatheca. In summary, this study answers long-standing questions concerning calcium signaling dynamics in the C. elegans spermatheca and suggests FLN-1 is needed in response to oocyte entry to trigger calcium release and coordinated contraction of the spermathecal tissue.

  1. Comparative toxicity of silver nanoparticles on oxidative stress and DNA damage in the nematode, Caenorhabditis elegans.

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    Ahn, Jeong-Min; Eom, Hyun-Jeong; Yang, Xinyu; Meyer, Joel N; Choi, Jinhee

    2014-08-01

    This study examined the effects of polyvinylpyrrolidone (PVP) surface coating and size on the organismal and molecular toxicity of silver nanoparticles (AgNPs) on the nematode, Caenorhabditis elegans. The toxicity of bare AgNPs and 8 and 38 nm PVP-coated AgNPs (PVP8-AgNPs, PVP38-AgNPs) were compared. The toxicity of AgNO3 was also tested because ion dissolution and particle-specific effects are often important characteristics determining Ag nanotoxicity. Comparative toxicity across AgNO3 and the three different types of AgNPs was first evaluated using a C. elegans mortality test by a direct comparison of the LC50 values. Subsequently, mutant screening followed by oxidative stress, mitochondrial toxicity and DNA damage assays were carried out at equitoxic (LC10 and LC50) concentrations to further assess the toxicity mechanism of AgNO3 and AgNPs. AgNO3 and bare AgNPs had similar toxicities, whereas PVP coating reduced the toxicity of the AgNPs significantly. Of the PVP-AgNPs, the smaller NPs were more toxic. Different groups of mutants responded differently to AgNO3 and AgNPs, which indicates that their toxicity mechanism might be different. AgNO3 and bare AgNPs induced mitochondrial membrane damage. None of the silver materials tested caused detectable polymerase-inhibiting DNA lesions in either the nucleus or mitochondria as measured by a quantitative PCR assay, but AgNO3, bare AgNPs and PVP8-AgNPs induced oxidative DNA damage. These results show that coatings on the AgNPs surface and the particle size make a clear contribution to the toxicity of the AgNPs, and oxidative stress-related mitochondrial and DNA damage appear to be potential mechanisms of toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Chlorpyrifos exposure reduces reproductive capacity owing to a damaging effect on gametogenesis in the nematode Caenorhabditis elegans.

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    Ruan, Qin-Li; Ju, Jing-Juan; Li, Yun-Hui; Li, Xiao-Bo; Liu, Ran; Liang, Ge-Yu; Zhang, Juan; Pu, Yue-Pu; Wang, Da-Yong; Yin, Li-Hong

    2012-07-01

    Previous studies have revealed that chlorpyrifos exposure adversely affects the reproductive capacity of male rodents. The present study investigated the reproductive toxicity of chlorpyrifos exposure and possible related mechanisms using the nematode Caenorhabditis elegans. L4 nematode larvae were exposed to chlorpyrifos at concentrations of 0.003, 0.03, 0.3 and 3.0 mg l(-1) for different durations. In addition to decreased brood size, reduced spermatid size, increased percentage of abnormal spermatids, suppressed spermatid activation and motility of sperm, damaged oocyte morphology, increased numbers of apoptotic cells and unfertilized oocytes were observed in nematodes exposed to various concentrations of chlorpyrifos. Moreover, expression patterns of the genes spe-10, spe-15, fer-1, prg-1, glp-1, mlh-1, cyb-3, ced-3, ced-4 and ced-9 (which are associated with spermatid size, spermatid activation and morphology, oocyte morphology, oocyte function, and apoptosis) were altered after chlorpyrifos exposure. Therefore, chlorpyrifos exposure may adversely affect fertility in nematodes by influencing both spermatogenesis and oogenesis. Alterations in the expression patterns of genes involved in gametogenesis may explain the corresponding changes in gametogenesis in nematodes exposed to chlorpyrifos. Hence, the model organism Caenorhabditis elegans is recommended for assessment of reproductive toxicity relating to gametogenesis. Copyright © 2011 John Wiley & Sons, Ltd.

  3. Immunofluorescent localization of thymidylate synthase in the development of Trichinella spiralis and Caenorhabditis elegans.

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    Gołos, Barbara; Dąbrowska, Magdalena; Wałajtys-Rode, Elżbieta; Zieliński, Zbigniew; Wińska, Patrycja; Cieśla, Joanna; Jagielska, Elżbieta; Moczoń, Tadeusz; Rode, Wojciech

    2012-05-01

    Localization of thymidylate synthase protein in Trichinella spiralis and Caenorhabditis elegans development was followed with the use of confocal microscopy, revealing similar expression patterns in both nematode species. In T. spiralis premature muscle larvae and C. elegans dauer, L3 and L4 larvae, thymidylate synthase was detected in the nerve ring and gonad primordia, as well as T. spiralis stichosome and C. elegans pharyngeal glandular cells. In developmentally arrested T. spiralis muscle larvae, the enzyme was found localized to the gonad primordia and stichosome. High enzyme level was also observed in the embryos developing in uteri of T. spiralis female adult and C. elegans hermaphrodite forms. In the case of T. spiralis adult forms, thymidylate synthase was detected in stichosome, along esophagus wall, as well as in egg and sperm cells. While the enzyme protein present in the embryos remains in accord with its known association with proliferating systems, thymidylate synthase presence in the nerve ring, and reproductive and secretory (T. spiralis stichosomal and C. elegans pharyngeal glandular cells) systems, points to a state of cell cycle-arrest, also known to preserve the enzyme protein. Copyright © 2012 Elsevier B.V. All rights reserved.

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

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    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.

  5. Inducible and titratable silencing of Caenorhabditis elegans neurons in vivo with histamine-gated chloride channels

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    Pokala, Navin; Liu, Qiang; Gordus, Andrew; Bargmann, Cornelia I.

    2014-01-01

    Recent progress in neuroscience has been facilitated by tools for neuronal activation and inactivation that are orthogonal to endogenous signaling systems. We describe here a chemical-genetic approach for inducible silencing of Caenorhabditis elegans neurons in intact animals, using the histamine-gated chloride channel HisCl1 from Drosophila and exogenous histamine. Administering histamine to freely moving C. elegans that express HisCl1 transgenes in neurons leads to rapid and potent inhibition of neural activity within minutes, as assessed by behavior, functional calcium imaging, and electrophysiology of neurons expressing HisCl1. C. elegans does not use histamine as an endogenous neurotransmitter, and exogenous histamine has little apparent effect on wild-type C. elegans behavior. HisCl1-histamine silencing of sensory neurons, interneurons, and motor neurons leads to behavioral effects matching their known functions. In addition, the HisCl1-histamine system can be used to titrate the level of neural activity, revealing quantitative relationships between neural activity and behavioral output. We use these methods to dissect escape circuits, define interneurons that regulate locomotion speed (AVA, AIB) and escape-related omega turns (AIB), and demonstrate graded control of reversal length by AVA interneurons and DA/VA motor neurons. The histamine-HisCl1 system is effective, robust, compatible with standard behavioral assays, and easily combined with optogenetic tools, properties that should make it a useful addition to C. elegans neurotechnology. PMID:24550306

  6. A screening-based platform for the assessment of cellular respiration in Caenorhabditis elegans.

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    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.

  7. Caenorhabditis elegans NONO-1: Insights into DBHS protein structure, architecture, and function.

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    Knott, Gavin J; Lee, Mihwa; Passon, Daniel M; Fox, Archa H; Bond, Charles S

    2015-12-01

    Members of the Drosophila behavior/human splicing (DBHS) protein family have been characterized in the vertebrates Homo sapiens and Mus musculus, and the invertebrates Drosophila melanogaster and Chironomus tentans. Collectively, both vertebrate and invertebrate DBHS proteins function throughout gene regulation, largely but not always, within the nucleus. In this study, we report a structural and bioinformatic analysis of the DBHS protein family to guide future studies into DBHS protein function. To explore the structural plasticity of the family, we describe the 2.4 Å crystal structure of Caenorhabditis elegans non-POU domain-containing octamer-binding protein 1 (NONO-1). The structure is dimeric, with a domain arrangement consistent with mammalian DBHS proteins. Comparison with the DBHS structures available from H. sapiens reveals that there is inherent domain flexibility within the homologous DBHS region. Mapping amino acid similarity within the family to the NONO-1 dimer highlights the dimer interface, coiled-coil oligomerization motif, and putative RNA binding surfaces. Surprisingly, the interior surface of RNA recognition motif 2 (RRM2) that faces a large internal void is highly variable, but the external β2-β3 loops of RRM2 show remarkable preservation. Overall, the DBHS region is under strong purifying selection, whereas the sequences N- and C-terminal to the DBHS region are less constrained. The findings described in this study provide a molecular basis for further investigation into the mechanistic function of the DBHS protein family in biology. © 2015 The Protein Society.

  8. The nematode Caenorhabditis elegans displays a chemotaxis behavior to tuberculosis-specific odorants

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    Mário F. Neto

    2016-08-01

    Full Text Available A simple, affordable diagnostic test for pulmonary tuberculosis (TB is urgently needed to improve detection of active Mycobacterium tuberculosis. Recently, it has been suggested that animal behavior can be used as a biosensor to signal the presence of human disease. For example, the giant African pouched rats can detect tuberculosis by sniffing sputum specimens while trained honeybees respond to three of the volatile organic compounds (VOCs detected in the breath of TB positive patients by proboscis extension. However, both rats and honeybees require animal housing facilities and professional trainers, which are outside the scope of most disease testing facilities. Here, we report that the innate olfactory behavioral response of the roundworm nematode Caenorhabditis elegans can be used to detect the TB-specific VOCs methyl p-anisate, methyl nicotinate, methyl phenylacetate and o-phenylanisole, in chemotaxis assays. Dauer larvae, a long-lived stress resistant alternative development state of C. elegans in which the animals can survive for extended periods of time in dry conditions with no food, were also demonstrated to detect the VOCs. We propose that exposing naive dauer larvae to TB-related VOCs and recording their response in this behavioral assay could lead to the development of a new method for TB diagnostics using breath as the sample type. Keywords: Tuberculosis, Caenorhabditis elegans, Chemotaxis, Volatile organic compounds, Diagnostics, Odorants

  9. Loss of Acetylcholine Signaling Reduces Cell Clearance Deficiencies in Caenorhabditis elegans.

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    Sérgio M Pinto

    Full Text Available The ability to eliminate undesired cells by apoptosis is a key mechanism to maintain organismal health and homeostasis. Failure to clear apoptotic cells efficiently can cause autoimmune diseases in mammals. Genetic studies in Caenorhabditis elegans have greatly helped to decipher the regulation of apoptotic cell clearance. In this study, we show that the loss of levamisole-sensitive acetylcholine receptor, but not of a typical neuronal acetylcholine receptor causes a reduction in the number of persistent cell corpses in worms suffering from an engulfment deficiency. This reduction is not caused by impaired or delayed cell death but rather by a partial restoration of the cell clearance capacity. Mutants in acetylcholine turn-over elicit a similar phenotype, implying that acetylcholine signaling is the process responsible for these observations. Surprisingly, tissue specific RNAi suggests that UNC-38, a major component of the levamisole-sensitive receptor, functions in the dying germ cell to influence engulfment efficiency. Animals with loss of acetylcholine receptor exhibit a higher fraction of cell corpses positive for the "eat-me" signal phosphatidylserine. Our results suggest that modulation by ion channels of ion flow across plasma membrane in dying cells can influence the dynamics of phosphatidylserine exposure and thus clearance efficiency.

  10. Long astral microtubules and RACK-1 stabilize polarity domains during maintenance phase in Caenorhabditis elegans embryos.

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    Erkang Ai

    2011-04-01

    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.

  11. Trans-generational influences of sulfamethoxazole on lifespan, reproduction and population growth of Caenorhabditis elegans.

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    Yu, Zhenyang; Sun, Guohua; Liu, Yanjun; Yin, Daqiang; Zhang, Jing

    2017-01-01

    Trans-generational effects are increasingly used to indicate long-term influences of environmental pollutants. However, such studies can be complex and yield inconclusive results. In this study, the trans-generational effects of sulfamethoxazole (SMX) on Caenorhabditis elegans on lifespan, reproduction and population growth were tested for 7 consecutive generations, which included gestating generation (F0), embryo-exposed generation (F1), germline-exposed generation (F2), the first non-exposed generation (F3) and the three following generations (F4-F6). Results showed that lifespan was significantly affected by embryo exposure (F1) at 400µm SMX with a value as low as 47% of the control. The reproduction (a total brood size as 49% of the control) and population growth (81% of the control) were significantly affected in germline exposure (F2). Lifespan and reproduction were severely inhibited in non-exposed generations, confirming the real trans-generational effects. Notably, initial reproduction and reproduction duration showed opposite generation-related changes, indicating their interplay in the overall brood size. The population growth rate was well correlated with median lethal time, brood size and initial reproduction, which indicated that the population would increase when the nematodes lived longer and reproduced more offspring within shorter duration. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Virulence of Klebsiella pneumoniae isolates harboring bla KPC-2 carbapenemase gene in a Caenorhabditis elegans model.

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    Jean-Philippe Lavigne

    Full Text Available Klebsiella pneumoniae carbapenemase (KPC is a carbapenemase increasingly reported worldwide in Enterobacteriaceae. The aim of this study was to analyze the virulence of several KPC-2-producing K. pneumoniae isolates. The studied strains were (i five KPC-2 clinical strains from different geographical origins, belonging to different ST-types and possessing plasmids of different incompatibility groups; (ii seven transformants obtained after electroporation of either these natural KPC plasmids or a recombinant plasmid harboring only the bla KPC-2 gene into reference strains K. pneumoniae ATCC10031/CIP53153; and (iii five clinical strains cured of plasmids. The virulence of K. pneumoniae isolates was evaluated in the Caenorhabditis elegans model. The clinical KPC producers and transformants were significantly less virulent (LT50: 5.5 days than K. pneumoniae reference strain (LT50: 4.3 days (p<0.01. However, the worldwide spread KPC-2 positive K. pneumoniae ST258 strains and reference strains containing plasmids extracted from K. pneumoniae ST258 strains had a higher virulence than KPC-2 strains belonging to other ST types (LT50: 5 days vs. 6 days, p<0.01. The increased virulence observed in cured strains confirmed this trend. The bla KPC-2 gene itself was not associated to increased virulence.

  13. P granules phase transition induced by cytoplasmic streaming in Caenorhabditis elegans embryo

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    Wang, Hang; Hu, GuoHui

    2017-01-01

    P granules are germ granules contained in Caenorhabditis elegans germ cells. The first germ cell is specified by the one-cell embryo in which P granules localize to the posterior. Previous studies suggested that the mechanism of the localization phenomena is induced by liquid-liquid phase transition (LLPT), in which the polarity proteins control the saturation point of P granules. In the present study, we propose that the P granules phase transition can be triggered by the cytoplasmic streaming. A two-phase flow model is employed to simulate the localization of P granules, i.e., the cytoplasm is considered as a liquid phase, and the droplet-like P granules are another liquid phase. With the presence of the cytoplasmic streaming, P granules, initially distributing uniformly in the entire one-cell embryo, eventually condense/dissolve in the cytoplasm phase, regulated by difference between the saturation pressure and the hydrodynamic pressure. The numerical results reveal that the cytoplasmic streaming has significant effects on the localization of P granules, as well as the embryo division.

  14. A multilayer protein-protein interaction network analysis of different life stages in Caenorhabditis elegans

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    Shinde, Pramod; Jalan, Sarika

    2015-12-01

    Molecular networks act as the backbone of cellular activities, providing an excellent opportunity to understand the developmental changes in an organism. While network data usually constitute only stationary network graphs, constructing a multilayer PPI network may provide clues to the particular developmental role at each stage of life and may unravel the importance of these developmental changes. The developmental biology model of Caenorhabditis elegans analyzed here provides a ripe platform to understand the patterns of evolution during the life stages of an organism. In the present study, the widely studied network properties exhibit overall similar statistics for all the PPI layers. Further, the analysis of the degree-degree correlation and spectral properties not only reveals crucial differences in each PPI layer but also indicates the presence of the varying complexity among them. The PPI layer of the nematode life stage exhibits various network properties different to the rest of the PPI layers, indicating the specific role of cellular diversity and developmental transitions at this stage. The framework presented here provides a direction to explore and understand the developmental changes occurring in the different life stages of an organism.

  15. Expression of Caenorhabditis elegans antimicrobial peptide NLP-31 in Escherichia coli

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    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.

  16. Systematic Functional Characterization of Human 21st Chromosome Orthologs in Caenorhabditis elegans.

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    Nordquist, Sarah K; Smith, Sofia R; Pierce, Jonathan T

    2018-01-24

    Individuals with Down syndrome have neurological and muscle impairments due to an additional copy of the human 21st chromosome (HSA21). Only a few of ~200 HSA21 genes encoding protein have been linked to specific Down syndrome phenotypes, while the remainder are understudied. To identify poorly characterized HSA21 genes required for nervous system function, we studied behavioral phenotypes caused by loss-of-function mutations in conserved HSA21 orthologs in the nematode Caenorhabditis elegans We identified ten HSA21 orthologs that are required for neuromuscular behaviors: cle-1 (COL18A1), cysl-2 (CBS), dnsn-1 (DONSON), eva-1 (EVA1C), mtq-2 (N6ATM1), ncam-1 (NCAM2), pad-2 (POFUT2), pdxk-1 (PDXK), rnt-1 (RUNX1), and unc-26 (SYNJ1).  We also found that three of these genes are required for normal release of the neurotransmitter acetylcholine. This includes a known synaptic gene unc-26 (SYNJ1), as well as uncharacterized genes pdxk-1 (PDXK) and mtq-2 (N6ATM1). As the first systematic functional analysis of HSA21 orthologs, this study may serve as a platform to understand genes that underlie phenotypes associated with Down syndrome. Copyright © 2018, G3: Genes, Genomes, Genetics.

  17. Drug-dependent behaviors and nicotinic acetylcholine receptor expressions in Caenorhabditis elegans following chronic nicotine exposure.

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    Polli, Joseph R; Dobbins, Dorothy L; Kobet, Robert A; Farwell, Mary A; Zhang, Baohong; Lee, Myon-Hee; Pan, Xiaoping

    2015-03-01

    Nicotine, the major psychoactive compound in tobacco, targets nicotinic acetylcholine receptors (nAChRs) and results in drug dependence. The nematode Caenorhabditis elegans' (C. elegans) genome encodes conserved and extensive nicotinic receptor subunits, representing a useful system to investigate nicotine-induced nAChR expressions in the context of drug dependence. However, the in vivo expression pattern of nAChR genes under chronic nicotine exposure has not been fully investigated. To define the role of nAChR genes involved in nicotine-induced locomotion changes and the development of tolerance to these effects, we characterized the locomotion behavior combining the use of two systems: the Worm Tracker hardware and the WormLab software. Our results indicate that the combined system is an advantageous alternative to define drug-dependent locomotion behavior in C. elegans. Chronic (24-h dosing) nicotine exposure at 6.17 and 61.7μM induced nicotine-dependent behaviors, including drug stimulation, tolerance/adaption, and withdrawal responses. Specifically, the movement speed of naïve worms on nicotine-containing environments was significantly higher than on nicotine-free environments, suggesting locomotion stimulation by nicotine. In contrast, the 24-h 6.17μM nicotine-treated worms exhibited significantly higher speeds on nicotine-free plates than on nicotine-containing plates. Furthermore significantly increased locomotion behavior during nicotine cessation was observed in worms treated with a higher nicotine concentration of 61.7μM. The relatively low locomotion speed of nicotine-treated worms on nicotine-containing environments also indicates adaption/tolerance of worms to nicotine following chronic nicotine exposure. In addition, this study provides useful information regarding the comprehensive in vivo expression profile of the 28 "core" nAChRs following different dosages of chronic nicotine treatments. Eleven genes (lev-1, acr-6, acr-7, acr-11, lev-8, acr

  18. Protective effects of novel organic selenium compounds against oxidative stress in the nematode Caenorhabditis elegans

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    Sílvio Terra Stefanello

    2015-01-01

    Full Text Available Organic selenium compounds possess numerous biological properties, including antioxidant activity. Yet, the high toxicity of some of them, such as diphenyl diselenide (DPDS, is a limiting factor in their current usage. Accordingly, we tested four novel organic selenium compounds in the non-parasite nematode Caenorhabditis elegans and compared their efficacy to DPDS. The novel organic selenium compounds are β-selenoamines 1-phenyl-3-(p-tolylselanylpropan-2-amine (C1 and 1-(2-methoxyphenylselanyl-3-phenylpropan-2-amine (C2 and analogs of DPDS 1,2-bis(2-methoxyphenyldiselenide (C3 and 1,2-bisp-tolyldiselenide (C4. Synchronized worms at the L4 larval stage were exposed for one hour in M9 buffer to these compounds. Oxidative stress conditions were induced by juglone (200 μM and heat shock (35 °C. Moreover, we evaluated C. elegans behavior, GST-4::GFP (glutathione S-transferase expression and the activity of acetylcholinesterase (AChE. All tested compounds efficiently restored viability in juglone stressed worms. However, DPDS, C2, C3 and C4 significantly decreased the defecation cycle time. Juglone-induced GST-4::GFP expression was not attenuated in worms pretreated with the novel compounds, except with C2. Finally, AChE activity was reduced by DPDS, C2, C3 and C4. To our knowledge, this is study firstly showed the effects of C1, C2, C3 and C4 selenium-derived compounds in C. elegans. Low toxic effects were noted, except for reduction in the defecation cycle, which is likely associated with AChE inhibition. The juglone-induced stress (reduced viability was fully reversed by compounds to control animal levels. C2 was also efficient in reducing the juglone-induced GST-4::GFP expression, suggesting the latter may mediate the stress induced by this compound. Future studies could be profitably directed at addressing additional molecular mechanisms that mediate the protective effects of these novel organic selenium compounds.

  19. Generation of an external guide sequence library for a reverse genetic screen in Caenorhabditis elegans

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    Yin Changxin

    2009-05-01

    Full Text Available Abstract Background A method for inhibiting the expression of particular genes using external guide sequences (EGSs has been developed in bacteria, mammalian cells and maize cells. Results To examine whether EGS technology can be used to down-regulate gene expression in Caenorhabditis elegans (C. elegans, we generated EGS-Ngfp-lacZ and EGS-Mtgfp that are targeted against Ngfp-lacZ and Mtgfp mRNA, respectively. These EGSs were introduced, both separately and together, into the C. elegans strain PD4251, which contains Ngfp-lacZ and Mtgfp. Consequently, the expression levels of Ngfp-lacZ and Mtgfp were affected by EGS-Ngfp-lacZ and EGS-Mtgfp, respectively. We further generated an EGS library that contains a randomized antisense domain of tRNA-derived EGS ("3/4 EGS". Examination of the composition of the EGS library showed that there was no obvious bias in the cloning of certain EGSs. A subset of EGSs was randomly chosen for screening in the C. elegans strain N2. About 6% of these EGSs induced abnormal phenotypes such as P0 slow postembryonic growth, P0 larval arrest, P0 larval lethality and P0 sterility. Of these, EGS-35 and EGS-83 caused the greatest phenotype changes, and their target mRNAs were identified as ZK858.7 mRNA and Lin-13 mRNA, respectively. Conclusion EGS technology can be used to down-regulate gene expression in C. elegans. The EGS library is a research tool for reverse genetic screening in C. elegans. These observations are potentially of great importance to further our understanding and use of C. elegans genomics.

  20. Generation of an external guide sequence library for a reverse genetic screen in Caenorhabditis elegans.

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    Yan, Qitao; Zhao, Rui; Zheng, Wenlin; Yin, Changxin; Zhang, Bao; Ma, Wenli

    2009-05-20

    A method for inhibiting the expression of particular genes using external guide sequences (EGSs) has been developed in bacteria, mammalian cells and maize cells. To examine whether EGS technology can be used to down-regulate gene expression in Caenorhabditis elegans (C. elegans), we generated EGS-Ngfp-lacZ and EGS-Mtgfp that are targeted against Ngfp-lacZ and Mtgfp mRNA, respectively. These EGSs were introduced, both separately and together, into the C. elegans strain PD4251, which contains Ngfp-lacZ and Mtgfp. Consequently, the expression levels of Ngfp-lacZ and Mtgfp were affected by EGS-Ngfp-lacZ and EGS-Mtgfp, respectively. We further generated an EGS library that contains a randomized antisense domain of tRNA-derived EGS ("3/4 EGS"). Examination of the composition of the EGS library showed that there was no obvious bias in the cloning of certain EGSs. A subset of EGSs was randomly chosen for screening in the C. elegans strain N2. About 6% of these EGSs induced abnormal phenotypes such as P0 slow postembryonic growth, P0 larval arrest, P0 larval lethality and P0 sterility. Of these, EGS-35 and EGS-83 caused the greatest phenotype changes, and their target mRNAs were identified as ZK858.7 mRNA and Lin-13 mRNA, respectively. EGS technology can be used to down-regulate gene expression in C. elegans. The EGS library is a research tool for reverse genetic screening in C. elegans. These observations are potentially of great importance to further our understanding and use of C. elegans genomics.

  1. Editor's Highlight: Comparative Toxicity of Organophosphate Flame Retardants and Polybrominated Diphenyl Ethers to Caenorhabditis elegans.

    Science.gov (United States)

    Behl, Mamta; Rice, Julie R; Smith, Marjo V; Co, Caroll A; Bridge, Matthew F; Hsieh, Jui-Hua; Freedman, Jonathan H; Boyd, Windy A

    2016-12-01

    With the phasing-out of the polybrominated diphenyl ether (PBDE) flame retardants due to concerns regarding their potential developmental toxicity, the use of replacement compounds such as organophosphate flame retardants (OPFRs) has increased. Limited toxicity data are currently available to estimate the potential adverse health effects of the OPFRs. The toxicological effects of 4 brominated flame retardants, including 3 PBDEs and 3,3',5,5'-tetrabromobisphenol A, were compared with 6 aromatic OPFRs and 2 aliphatic OPFRs. The effects of these chemicals were determined using 3 biological endpoints in the nematode Caenorhabditis elegans (feeding, larval development, and reproduction). Because C. elegans development was previously reported to be sensitive to mitochondrial function, results were compared with those from an in vitro mitochondrial membrane permeabilization (MMP) assay. Overall 11 of the 12 flame retardants were active in 1 or more C. elegans biological endpoints, with only tris(2-chloroethyl) phosphate inactive across all endpoints including the in vitro MMP assay. For 2 of the C. elegans endpoints, at least 1 OPFR had similar toxicity to the PBDEs: triphenyl phosphate (TPHP) inhibited larval development at levels comparable to the 3 PBDEs; whereas TPHP and isopropylated phenol phosphate (IPP) affected C. elegans reproduction at levels similar to the PBDE commercial mixture, DE-71. The PBDEs reduced C. elegans feeding at lower concentrations than any OPFR. In addition, 9 of the 11 chemicals that inhibited C. elegans larval development also caused significant mitochondrial toxicity. These results suggest that some of the replacement aromatic OPFRs may have levels of toxicity comparable to PBDEs. Published by Oxford University Press on behalf of the Society of Toxicology 2016. This work is written by US Government employees and is in the public domain in the US.

  2. 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.

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

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    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.

  4. Cell-Autonomous Gβ Signaling Defines Neuron-Specific Steady State Serotonin Synthesis in Caenorhabditis elegans.

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    Xu, Lu; Choi, Sunju; Xie, Yusu; Sze, Ji Ying

    2015-09-01

    Heterotrimeric G proteins regulate a vast array of cellular functions via specific intracellular effectors. Accumulating pharmacological and biochemical studies implicate Gβ subunits as signaling molecules interacting directly with a wide range of effectors to modulate downstream cellular responses, in addition to their role in regulating Gα subunit activities. However, the native biological roles of Gβ-mediated signaling pathways in vivo have been characterized only in a few cases. Here, we identified a Gβ GPB-1 signaling pathway operating in specific serotonergic neurons to the define steady state serotonin (5-HT) synthesis, through a genetic screen for 5-HT synthesis mutants in Caenorhabditis elegans. We found that signaling through cell autonomous GPB-1 to the OCR-2 TRPV channel defines the baseline expression of 5-HT synthesis enzyme tryptophan hydroxylase tph-1 in ADF chemosensory neurons. This Gβ signaling pathway is not essential for establishing the serotonergic cell fates and is mechanistically separated from stress-induced tph-1 upregulation. We identified that ADF-produced 5-HT controls specific innate rhythmic behaviors. These results revealed a Gβ-mediated signaling operating in differentiated cells to specify intrinsic functional properties, and indicate that baseline TPH expression is not a default generic serotonergic fate, but is programmed in a cell-specific manner in the mature nervous system. Cell-specific regulation of TPH expression could be a general principle for tailored steady state 5-HT synthesis in functionally distinct neurons and their regulation of innate behavior.

  5. Cell-Autonomous Gβ Signaling Defines Neuron-Specific Steady State Serotonin Synthesis in Caenorhabditis elegans.

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    Lu Xu

    2015-09-01

    Full Text Available Heterotrimeric G proteins regulate a vast array of cellular functions via specific intracellular effectors. Accumulating pharmacological and biochemical studies implicate Gβ subunits as signaling molecules interacting directly with a wide range of effectors to modulate downstream cellular responses, in addition to their role in regulating Gα subunit activities. However, the native biological roles of Gβ-mediated signaling pathways in vivo have been characterized only in a few cases. Here, we identified a Gβ GPB-1 signaling pathway operating in specific serotonergic neurons to the define steady state serotonin (5-HT synthesis, through a genetic screen for 5-HT synthesis mutants in Caenorhabditis elegans. We found that signaling through cell autonomous GPB-1 to the OCR-2 TRPV channel defines the baseline expression of 5-HT synthesis enzyme tryptophan hydroxylase tph-1 in ADF chemosensory neurons. This Gβ signaling pathway is not essential for establishing the serotonergic cell fates and is mechanistically separated from stress-induced tph-1 upregulation. We identified that ADF-produced 5-HT controls specific innate rhythmic behaviors. These results revealed a Gβ-mediated signaling operating in differentiated cells to specify intrinsic functional properties, and indicate that baseline TPH expression is not a default generic serotonergic fate, but is programmed in a cell-specific manner in the mature nervous system. Cell-specific regulation of TPH expression could be a general principle for tailored steady state 5-HT synthesis in functionally distinct neurons and their regulation of innate behavior.

  6. Toxicity evaluation of prodigiosin from Serratia marcescens in a Caenorhabditis elegans model

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    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.

  7. STEM Analysis of Caenorhabditis elegans muscle thick filaments: evidence for microdifferentiated substructures

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    Muller, S. A.; Haner, M.; Ortiz, I.; Aebi, U.; Epstein, H. F.

    2001-01-01

    In the thick filaments of body muscle in Caenorhabditis elegans, myosin A and myosin B isoforms and a subpopulation of paramyosin, a homologue of myosin heavy chain rods, are organized about a tubular core. As determined by scanning transmission electron microscopy, the thick filaments show a continuous decrease in mass-per-length (MPL) from their central zones to their polar regions. This is consistent with previously reported morphological studies and suggests that both their content and structural organization are microdifferentiated as a function of position. The cores are composed of a second distinct subpopulation of paramyosin in association with the alpha, beta, and gamma-filagenins. MPL measurements suggest that cores are formed from seven subfilaments containing four strands of paramyosin molecules, rather than the two originally proposed. The periodic locations of the filagenins within different regions and the presence of a central zone where myosin A is located, implies that the cores are also microdifferentiated with respect to molecular content and structure. This differentiation may result from a novel "induced strain" assembly mechanism based upon the interaction of the filagenins, paramyosin and myosin A. The cores may then serve as "differentiated templates" for the assembly of myosin B and paramyosin in the tapering, microdifferentiated polar regions of the thick filaments.

  8. RbAp46/48LIN-53 Is Required for Holocentromere Assembly in Caenorhabditis elegans

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    Bernard Chi Hang Lee

    2016-03-01

    Full Text Available Centromeres, the specialized chromosomal regions for recruiting kinetochores and directing chromosome segregation, are epigenetically marked by a centromeric histone H3 variant, CENP-A. To maintain centromere identity through cell cycles, CENP-A diluted during DNA replication is replenished. The licensing factor M18BP1KNL-2 is known to recruit CENP-A to holocentromeres. Here, we show that RbAp46/48LIN-53, a conserved histone chaperone, is required for CENP-AHCP-3 localization in holocentric Caenorhabditis elegans. Indeed, RbAp46/48LIN-53 and CENP-AHCP-3 localizations are interdependent. RbAp46/48LIN-53 localizes to the centromere during metaphase in a CENP-AHCP-3- and M18BP1KNL-2-dependent manner, suggesting CENP-AHCP-3 loading may occur before anaphase. RbAp46/48LIN-53 does not function at the centromere through histone acetylation, H3K27 trimethylation, or its known chromatin-modifying complexes. RbAp46/48LIN-53 may function independently to escort CENP-AHCP-3 for holocentromere assembly but is dispensable for other kinetochore protein recruitment. Nonetheless, depletion of RbAp46/48LIN-53 leads to anaphase bridges and chromosome missegregation. This study unravels the holocentromere assembly hierarchy and its conservation with monocentromeres.

  9. The fog-3 gene and regulation of cell fate in the germ line of Caenorhabditis elegans

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    Ellis, R.; Kimble, J. [Univ. of Wisconsin, Madison, WI (United States)

    1995-02-01

    In the nematode Caenorhabditis elegans, germ cells normally adopt one of three fates: mitosis, spermatogenesis or oogenesis. We have identified and characterized the gene fog-3, which is required for germ cells to differentiate as sperm rather than as oocytes. Analysis of double mutants suggests that fog-3 is absolutely required for spermatogenesis and acts at the end of the regulatory hierarchy controlling sex determination for the germ line. By contrast, mutations in fog-3 do not alter the sexual identity of other tissues. We also have characterized the null phenotype of fog-1, another gene required for spermatogenesis; we demonstrate that it too controls the sexual identity of germ cells but not of other tissues. Finally, we have studied the same interaction of these two fog genes with gld-1, a gene required for germ cells to undergo oogenesis rather than mitosis. On the basis of these results, we propose that germ-cell fate might be controlled by a set of inhibitory interactions among genes that specify one of three fates: mitosis, spermatogenesis or oogenesis. Such a regulatory network would link the adoption of one germ-cell fate to the suppression of the other two. 68 refs., 7 figs., 6 tabs.

  10. The E2F-DP1 Transcription Factor Complex Regulates Centriole Duplication in Caenorhabditis elegans

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    Jacqueline G. Miller

    2016-03-01

    Full Text Available Centrioles play critical roles in the organization of microtubule-based structures, from the mitotic spindle to cilia and flagella. In order to properly execute their various functions, centrioles are subjected to stringent copy number control. Central to this control mechanism is a precise duplication event that takes place during S phase of the cell cycle and involves the assembly of a single daughter centriole in association with each mother centriole . Recent studies have revealed that posttranslational control of the master regulator Plk4/ZYG-1 kinase and its downstream effector SAS-6 is key to ensuring production of a single daughter centriole. In contrast, relatively little is known about how centriole duplication is regulated at a transcriptional level. Here we show that the transcription factor complex EFL-1-DPL-1 both positively and negatively controls centriole duplication in the Caenorhabditis elegans embryo. Specifically, we find that down regulation of EFL-1-DPL-1 can restore centriole duplication in a zyg-1 hypomorphic mutant and that suppression of the zyg-1 mutant phenotype is accompanied by an increase in SAS-6 protein levels. Further, we find evidence that EFL-1-DPL-1 promotes the transcription of zyg-1 and other centriole duplication genes. Our results provide evidence that in a single tissue type, EFL-1-DPL-1 sets the balance between positive and negative regulators of centriole assembly and thus may be part of a homeostatic mechanism that governs centriole assembly.

  11. A Wnt-Frz/Ror-Dsh pathway regulates neurite outgrowth in Caenorhabditis elegans.

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    Song Song

    2010-08-01

    Full Text Available One of the challenges to understand the organization of the nervous system has been to determine how axon guidance molecules govern axon outgrowth. Through an unbiased genetic screen, we identified a conserved Wnt pathway which is crucial for anterior-posterior (A/P outgrowth of neurites from RME head motor neurons in Caenorhabditis elegans. The pathway is composed of the Wnt ligand CWN-2, the Frizzled receptors CFZ-2 and MIG-1, the co-receptor CAM-1/Ror, and the downstream component Dishevelled/DSH-1. Among these, CWN-2 acts as a local attractive cue for neurite outgrowth, and its activity can be partially substituted with other Wnts, suggesting that spatial distribution plays a role in the functional specificity of Wnts. As a co-receptor, CAM-1 functions cell-autonomously in neurons and, together with CFZ-2 and MIG-1, transmits the Wnt signal to downstream effectors. Yeast two-hybrid screening identified DSH-1 as a binding partner for CAM-1, indicating that CAM-1 could facilitate CWN-2/Wnt signaling by its physical association with DSH-1. Our study reveals an important role of a Wnt-Frz/Ror-Dsh pathway in regulating neurite A/P outgrowth.

  12. The Caenorhabditis elegans presenilin sel-12 is required for mesodermal patterning and muscle function.

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    Eimer, Stefan; Donhauser, Roland; Baumeister, Ralf

    2002-11-01

    Mutations in presenilin genes impair Notch signalling and, in humans, have been implicated in the development of familial Alzheimer's disease. We show here that a reduction of the activity of the Caenorhabditis elegans presenilin sel-12 results in a late defect during sex muscle development. The morphological abnormalities and functional deficits in the sex muscles contribute to the egg-laying defects seen in sel-12 hermaphrodites and to the severely reduced mating efficiency of sel-12 males. Both defects can be rescued by expressing sel-12 from the hlh-8 promoter that is active during the development of the sex muscle-specific M lineage, but not by expressing sel-12 from late muscle-specific promoters. Both weak and strong sel-12 mutations cause defects in the sex muscles that resemble the defects we found in lin-12 hypomorphic alleles, suggesting a previously uncharacterised LIN-12 signalling event late in postembryonic mesoderm development. Together with a previous study indicating a role of lin-12 and sel-12 during the specification of the pi cell lineage required for proper vulva-uterine connection, our data suggest that the failure of sel-12 animals to lay eggs properly is caused by defects in at least two independent signalling events in different tissues during development.

  13. The role of the presenilin-1 homologue gene sel-12 of Caenorhabditis elegans in apoptotic activities.

    Science.gov (United States)

    Kitagawa, Naoyuki; Shimohama, Shun; Oeda, Tomoko; Uemura, Kengo; Kohno, Ryuichi; Kuzuya, Akira; Shibasaki, Hiroshi; Ishii, Naoaki

    2003-04-04

    Many cases of autosomal dominant early onset familial Alzheimer's disease result from mutations in presenilin-1 (PS1). In this study, we examined the role of the PS1 homologue gene sel-12 of Caenorhabditis elegans under oxidative stress and clarified the sel-12-induced apoptosis. A genetic null allele mutant, sel-12(ar171), showed resistance to oxidative stress and prevented mitochondrial dysfunction-induced apoptosis. On the other hand, another allele mutant, sel-12(ar131), that carries a missense mutation showed a proapoptotic activity, which may be the result of a gain of function property. Also, sel-12(ar131)-induced apoptosis was ced-3- and ced-4-dependent. Dantrolene, which specifically inhibits Ca(2+) release from endoplasmic reticulum stores, prevents sel-12(ar131)-induced apoptosis. SEL-12, which is localized in the endoplasmic reticulum, may induce apoptosis through abnormal calcium release from the endoplasmic reticulum. Together, with the previous finding that human PS1 could substitute for SEL-12, these results suggest the similar involvement of PS1-inducing apoptosis under oxidative stress and mitochondrial dysfunction in the Alzheimer's Disease brain.

  14. Uncovering the mechanisms of Caenorhabditis elegans ageing from global quantification of the underlying landscape.

    Science.gov (United States)

    Zhao, Lei; Wang, Jin

    2016-11-01

    Recent studies on Caenorhabditis elegans reveal that gene manipulations can extend its lifespan several fold. However, how the genes work together to determine longevity is still an open question. Here we construct a gene regulatory network for worm ageing and quantify its underlying potential and flux landscape. We found ageing and rejuvenation states can emerge as basins of attraction at certain gene expression levels. The system state can switch from one attractor to another driven by the intrinsic or external perturbations through genetics or the environment. Furthermore, we simulated gene silencing experiments and found that the silencing of longevity-promoting or lifespan-limiting genes leads to ageing or rejuvenation domination, respectively. This indicates that the difference in depths between ageing and the rejuvenation attractor is highly correlated with worm longevity. We further uncovered some key genes and regulations which have a strong influence on landscape basin stability. A dynamic landscape model is proposed to describe the whole process of ageing: the ageing attractor dominates when senescence progresses. We also uncovered the oscillation dynamics, and a similar behaviour was observed in the long-lived creature Turritopsis dohrnii Our landscape theory provides a global and physical approach to explore the underlying mechanisms of ageing. © 2016 The Author(s).

  15. The anti-aging and anti-oxidation effects of tea water extract in Caenorhabditis elegans.

    Science.gov (United States)

    Fei, Tianyi; Fei, Jian; Huang, Fang; Xie, Tianpei; Xu, Jifeng; Zhou, Yi; Yang, Ping

    2017-10-15

    Tea includes puer tea, black tea, green tea and many others. By using model organism Caenorhabditis elegans, the anti-aging and anti-oxidation effects of tea water extract were systemically examined in this study. We found that water extract of puer tea, black tea and green tea all increased the lifespan of worms, postponed Aβ-induced progressive paralysis in Alzheimer's disease transgenic worms, and improved the tolerance of worms to the oxidative stress induced by heavy metal Cr6+. Moreover, the anti-oxidation effects of tea water extract at low concentration were different among 4 kinds of brands of green tea. The underlying mechanisms were further explored using genetically manipulated-mutant worms. The anti-oxidative stress effects of green tea water extract depend on the dietary restriction and germline signaling pathways, but not the FOXO and mitochondrial respiratory chain signals. Therefore, tea water extract provides benefits of anti-aging, anti-AD and anti-oxidation. Copyright © 2017. Published by Elsevier Inc.

  16. 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.

  17. Behavioral deficits and neural damage of Caenorhabditis elegans induced by three rare earth elements.

    Science.gov (United States)

    Xu, Tiantian; Zhang, Manke; Hu, Jiani; Li, Zihan; Wu, Taipu; Bao, Jianing; Wu, Siyu; Lei, Lili; He, Defu

    2017-08-01

    Rare earth elements (REEs) are widely used in industry, agriculture, medicine and daily life in recent years. However, environmental and health risks of REEs are still poorly understood. In this study, neurotoxicity of trichloride neodymium, praseodymium and scandium were evaluated using nematode Caenorhabditis elegans as the assay system. Median lethal concentrations (48 h) were 99.9, 157.2 and 106.4 mg/L for NdCl3, PrCl3 and ScCl3, respectively. Sublethal dose (10-30 mg/L) of these trichloride salts significantly inhibited body length of nematodes. Three REEs resulted in significant declines in locomotor frequency of body bending, head thrashing and pharyngeal pumping. In addition, mean speed and wavelength of crawling movement were significantly reduced after chronic exposure. Using transgenic nematodes, we found NdCl3, PrCl3 and ScCl3 resulted in loss of dendrite and soma of neurons, and induced down-expression of dat-1::GFP and unc-47::GFP. It indicates that REEs can lead to damage of dopaminergic and GABAergic neurons. Our data suggest that exposure to REEs may cause neurotoxicity of inducing behavioral deficits and neural damage. These findings provide useful information for understanding health risk of REE materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Wnt Ligands Differentially Regulate Toxicity and Translocation of Graphene Oxide through Different Mechanisms in Caenorhabditis elegans

    Science.gov (United States)

    Zhi, Lingtong; Ren, Mingxia; Qu, Man; Zhang, Hanyu; Wang, Dayong

    2016-12-01

    In this study, we investigated the possible involvement of Wnt signals in the control of graphene oxide (GO) toxicity using the in vivo assay system of Caenorhabditis elegans. In nematodes, the Wnt ligands, CWN-1, CWN-2, and LIN-44, were found to be involved in the control of GO toxicity. Mutation of cwn-1 or lin-44 gene induced a resistant property to GO toxicity and resulted in the decreased accumulation of GO in the body of nematodes, whereas mutation of cwn-2 gene induces a susceptible property to GO toxicity and an enhanced accumulation of GO in the body of nematodes. Genetic interaction assays demonstrated that mutation of cwn-1 or lin-44 was able to suppress the susceptibility to GO toxicity shown in the cwn-2 mutants. Loss-of-function mutations in all three of these Wnt ligand genes resulted in the resistance of nematodes to GO toxicity. Moreover, the Wnt ligands might differentially regulate the toxicity and translocation of GO through different mechanisms. These findings could be important in understanding the function of Wnt signals in the regulation of toxicity from environmental nanomaterials.

  19. Neuronal ERK signaling in response to graphene oxide in nematode Caenorhabditis elegans.

    Science.gov (United States)

    Qu, Man; Li, Yunhui; Wu, Qiuli; Xia, Yankai; Wang, Dayong

    2017-05-01

    ERK signaling is one of the important mitogen-activated protein kinases (MAPKs). However, the role of ERK signaling in the regulation of response to engineered nanomaterial exposure is still largely unclear. In this study, using in vivo assay system of Caenorhabditis elegans, we investigated the function of ERK signaling in response to graphene oxide (GO) exposure and the underlying molecular mechanism. GO exposure increased the expression of MEK-2/MEK and MPK-1/ERK in the ERK signaling pathway. Mutation of mek-2 or mpk-1 resulted in a susceptibility to GO toxicity. Both the MEK-2 and the MPK-1 acted in neurons to regulate the response to GO exposure, and the neuronal expression of MEK-2 or MPK-1 caused a resistance to GO toxicity. In the neurons, SKN-1b/Nrf acted downstream of the MPK-1, and AEX-3, a guanine exchange factor for GTPase, further acted downstream of the SKN-1b to regulate the response to GO exposure. Therefore, a signaling cascade of MEK-2-MPK-1-SKN-1b/-AEX-3 was identified in the neurons required for the regulation of response to GO exposure. Moreover, genetic interaction assay demonstrated that the neuronal ERK signaling-mediated signaling pathway and the intestinal p38 MAPK-mediated signaling pathway functioned synergistically in the regulation of response to GO exposure. Our results highlight the crucial function of the neuronal ERK signaling in the regulation of response to nanomaterial exposure in organisms.

  20. Functional and Genetic Analysis of VAB-10 Spectraplakin in Caenorhabditis elegans.

    Science.gov (United States)

    Gally, Christelle; Zhang, Huimin; Labouesse, Michel

    2016-01-01

    Intermediate filaments (IFs) are involved in multiple cellular processes that are essential for the maintenance of cell and tissue integrity. To achieve this crucial function, IFs have to be organized as long and resistant filaments across the cells and to be tightly anchored at the cell periphery. This anchoring takes place at the level desmosomes and hemidesmosomes through proteins belonging to the spectraplakin family. Here, we focus on the sole nematode Caenorhabditis elegans spectraplakin locus vab-10 that is essential to connect the epidermis to the cuticle apically and to the muscles basally. After briefly reviewing the structure of the gene, we first present the genetic tools available to study this gene as well as the reagents to examine the distribution of its translation products. We discuss the functional assays that enable examining their function. Finally, we detail a genetic method to identify spectraplakin functional partners through RNAi screens, and a biochemical method to examine the phosphorylation status of IFs. © 2016 Elsevier Inc. All rights reserved.

  1. Germ Granules Prevent Accumulation of Somatic Transcripts in the Adult Caenorhabditis elegans Germline.

    Science.gov (United States)

    Knutson, Andrew Kekūpa'a; Egelhofer, Thea; Rechtsteiner, Andreas; Strome, Susan

    2017-05-01

    The germ cells of multicellular organisms protect their developmental potential through specialized mechanisms. A shared feature of germ cells from worms to humans is the presence of nonmembrane-bound, ribonucleoprotein organelles called germ granules. Depletion of germ granules in Caenorhabditis elegans (i.e., P granules) leads to sterility and, in some germlines, expression of the neuronal transgene unc-119::gfp and the muscle myosin MYO-3 Thus, P granules are hypothesized to maintain germ cell totipotency by preventing somatic development, although the mechanism by which P granules carry out this function is unknown. In this study, we performed transcriptome and single molecule RNA-FISH analyses of dissected P granule-depleted gonads at different developmental stages. Our results demonstrate that P granules are necessary for adult germ cells to downregulate spermatogenesis RNAs and to prevent the accumulation of numerous soma-specific RNAs. P granule-depleted gonads that express the unc-119::gfp transgene also express many other genes involved in neuronal development and concomitantly lose expression of germ cell fate markers. Finally, we show that removal of either of two critical P-granule components, PGL-1 or GLH-1, is sufficient to cause germ cells to express UNC-119::GFP and MYO-3 and to display RNA accumulation defects similar to those observed after depletion of P granules. Our data identify P granules as critical modulators of the germline transcriptome and guardians of germ cell fate. Copyright © 2017 by the Genetics Society of America.

  2. The R148.3 Gene Modulates Caenorhabditis elegans Lifespan and Fat Metabolism

    Directory of Open Access Journals (Sweden)

    Catherine Roy-Bellavance

    2017-08-01

    Full Text Available Despite many advances, the molecular links between energy metabolism and longevity are not well understood. Here, we have used the nematode model Caenorhabditis elegans to study the role of the yet-uncharacterized gene R148.3 in fat accumulation and lifespan. In wild-type worms, a R148.3p::GFP reporter showed enhanced expression throughout life in the pharynx, in neurons, and in muscles. Functionally, a protein fusing a predicted 22 amino acid N-terminal signal sequence (SS of R148.3 to mCherry displayed robust accumulation in coelomyocytes, indicating that R148.3 is a secreted protein. Systematic depletion of R148.3 by RNA interference (RNAi at L1 but not at young-adult stage enhanced triglyceride accumulation, which was associated with increased food uptake and lower expression of genes involved in lipid oxidation. However, RNAi of R148.3 at both L1 and young-adult stages robustly diminished mean and maximal lifespan of wild-type worms, and also abolished the long-lived phenotypes of eat-2 and daf-2/InsR mutants. Based on these data, we propose that R148.3 is an SS that modulates fat mass and longevity in an independent manner.

  3. The R148.3 Gene Modulates Caenorhabditis elegans Lifespan and Fat Metabolism.

    Science.gov (United States)

    Roy-Bellavance, Catherine; Grants, Jennifer M; Miard, Stéphanie; Lee, Kayoung; Rondeau, Évelyne; Guillemette, Chantal; Simard, Martin J; Taubert, Stefan; Picard, Frédéric

    2017-08-07

    Despite many advances, the molecular links between energy metabolism and longevity are not well understood. Here, we have used the nematode model Caenorhabditis elegans to study the role of the yet-uncharacterized gene R148.3 in fat accumulation and lifespan. In wild-type worms, a R148.3p::GFP reporter showed enhanced expression throughout life in the pharynx, in neurons, and in muscles. Functionally, a protein fusing a predicted 22 amino acid N-terminal signal sequence (SS) of R148.3 to mCherry displayed robust accumulation in coelomyocytes, indicating that R148.3 is a secreted protein. Systematic depletion of R148.3 by RNA interference (RNAi) at L1 but not at young-adult stage enhanced triglyceride accumulation, which was associated with increased food uptake and lower expression of genes involved in lipid oxidation. However, RNAi of R148.3 at both L1 and young-adult stages robustly diminished mean and maximal lifespan of wild-type worms, and also abolished the long-lived phenotypes of eat-2 and daf-2/InsR mutants. Based on these data, we propose that R148.3 is an SS that modulates fat mass and longevity in an independent manner. Copyright © 2017 Roy-Bellavance et al.

  4. Lactobacillus casei stimulates phase-II detoxification system and rescues malathion-induced physiological impairments in Caenorhabditis elegans.

    Science.gov (United States)

    Kamaladevi, Arumugam; Ganguli, Abhijit; Balamurugan, Krishnaswamy

    2016-01-01

    Malathion, an organophosphorus insecticide, is renowned for its inhibitory action on acetylcholinesterase (AChE) enzyme that eventually leads to widespread disturbance in the normal physiological and behavioral activities of any organism. Lactic acid bacteria (LAB) are still an underexploited and inexhaustible source of significant pharmaceutical thrust. In the present study, Caenorhabditis elegans was employed to identify and characterize the indigenous LAB isolated from different traditional food against malathion-induced toxicity. The results demonstrated that malathion at its LD50 concentration decreased various C. elegans physiological parameters such as survival, feeding, and locomotion. Among the screened isolates, L. casei exhibited an excellent protective efficacy against malathion-induced toxicity by increasing the level of AChE and thereby rescued all physiological parameters of C. elegans. In addition, short-term exposure and food choice assay divulged that L. casei could serve as a better food to protect C. elegans from noxious environment. The expression analysis unveiled that L. casei gavage upregulated the phase-II detoxification enzymes coding genes metallothioneins (mtl-1 and mtl-2) and glutathione-S-transferase (gst-8) and thereby eliminated malathion from the host system. Furthermore, the upregulation of ace-3 along with down-regulation of cyp35a in the nematodes supplemented with L. casei could be attributed to attenuate the malathion-induced physiological defects in C. elegans. Thus, the present study reports that an indigenous LAB-L. casei could serve as a promising protective agent against the harmful effects of pesticide. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. GATA transcription factor as a likely key regulator of the Caenorhabditis elegans innate immune response against gut pathogens.

    Science.gov (United States)

    Yang, Wentao; Dierking, Katja; Rosenstiel, Philip C; Schulenburg, Hinrich

    2016-08-01

    Invertebrate defence against pathogens exclusively relies on components of the innate immune system. Comprehensive information has been collected over the last years on the molecular components of invertebrate immunity and the involved signalling processes, especially for the main invertebrate model species, the fruitfly Drosophila melanogaster and the nematode Caenorhabditis elegans. Yet, the exact regulation of general and specific defences is still not well understood. In the current study, we take advantage of a recently established database, WormExp, which combines all available gene expression studies for C. elegans, in order to explore commonalities and differences in the regulation of nematode immune defence against a large variety of pathogens versus food microbes. We identified significant overlaps in the transcriptional response towards microbes, especially pathogenic bacteria. We also found that the GATA motif is overrepresented in many microbe-induced gene sets and in targets of other previously identified regulators of worm immunity. Moreover, the activated targets of one of the known C. elegans GATA transcription factors, ELT-2, are significantly enriched in the gene sets, which are differentially regulated by gut-infecting pathogens. These findings strongly suggest that GATA transcription factors and particularly ELT-2 play a central role in regulating the C. elegans immune response against gut pathogens. More specific responses to distinct pathogens may be mediated by additional transcription factors, either acting alone or jointly with GATA transcription factors. Taken together, our analysis of the worm's transcriptional response to microbes provides a new perspective on the C. elegans immune system, which we propose to be coordinated by GATA transcription factor ELT-2 in the gut. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  6. Fourier-Based Diffraction Analysis of Live Caenorhabditis elegans.

    Science.gov (United States)

    Magnes, Jenny; Hastings, Harold M; Raley-Susman, Kathleen M; Alivisatos, Clara; Warner, Adam; Hulsey-Vincent, Miranda

    2017-09-13

    This manuscript describes how to classify nematodes using temporal far-field diffraction signatures. A single C. elegans is suspended in a water column inside an optical cuvette. A 632 nm continuous wave HeNe laser is directed through the cuvette using front surface mirrors. A significant distance of at least 20-30 cm traveled after the light passes through the cuvette ensures a useful far-field (Fraunhofer) diffraction pattern. The diffraction pattern changes in real time as the nematode swims within the laser beam. The photodiode is placed off-center in the diffraction pattern. The voltage signal from the photodiode is observed in real time and recorded using a digital oscilloscope. This process is repeated for 139 wild type and 108 "roller" C. elegans. Wild type worms exhibit a rapid oscillation pattern in solution. The "roller" worms have a mutation in a key component of the cuticle that interferes with smooth locomotion. Time intervals that are not free of saturation and inactivity are discarded. It is practical to divide each average by its maximum to compare relative intensities. The signal for each worm is Fourier transformed so that the frequency pattern for each worm emerges. The signal for each type of worm is averaged. The averaged Fourier spectra for the wild type and the "roller" C. elegans are distinctly different and reveal that the dynamic worm shapes of the two different worm strains can be distinguished using Fourier analysis. The Fourier spectra of each worm strain match an approximate model using two different binary worm shapes that correspond to locomotory moments. The envelope of the averaged frequency distribution for actual and modeled worms confirms the model matches the data. This method can serve as a baseline for Fourier analysis for many microscopic species, as every microorganism will have its unique Fourier spectrum.

  7. Comparative characterization of three D-aspartate oxidases and one D-amino acid oxidase from Caenorhabditis elegans.

    Science.gov (United States)

    Katane, Masumi; Saitoh, Yasuaki; Seida, Yousuke; Sekine, Masae; Furuchi, Takemitsu; Homma, Hiroshi

    2010-06-01

    Previously, we cloned cDNAs for four Caenorhabditis elegans genes (F20 Hp, C47Ap, F18Ep, and Y69Ap genes) that were annotated in the database as encoding D-amino acid oxidase (DAO) or D-aspartate oxidase (DDO) proteins. These genes were expressed in Escherichia coli, and the recombinant C47Ap and F18Ep were shown to have functional DDO activities, while Y69Ap had functional DAO activity. In this study, we improved the E. coli culture conditions for the production of recombinant F20 Hp and, following purification of the protein, revealed that it has functional DDO activity. The kinetic properties of recombinant C47Ap (DDO-1), F18Ep (DDO-2), F20 Hp (DDO-3), and Y69Ap (DAO) were also determined and compared with recombinant human DDO and DAO. In contrast to the low catalytic efficiency of human DDO for D-Glu, all three C. elegans DDOs showed higher catalytic efficiencies for D-Glu than D-Asp or N-methyl-D-Asp. The catalytic efficiency of C. elegans DAO for D-Ser was substantially lower than that of human DAO, while the C. elegans DAO was more efficient at deamination of basic D-amino acids (D-Arg and D-His) than human DAO. Collectively, our results indicate that C. elegans contains at least three genes that encode functional DDOs, and one gene encoding a functional DAO, and that these enzymes have different and distinctive properties.

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

    Science.gov (United States)

    Sidoli, Simone; Vandamme, Julien; Salcini, Anna Elisabetta; Jensen, Ole N

    2016-02-01

    We applied a middle-down proteomics strategy for large-scale protein analysis during in vivo development of Caenorhabditis elegans. We characterized PTMs on histone H3 N-terminal tails at eight time points during the C. elegans lifecycle, including embryo, larval stages (L1-L4), dauer, and L1/L4 postdauer. Histones were analyzed by our optimized middle-down protein sequencing platform using high mass accuracy MS/MS. This allows quantification of intact histone tails and detailed characterization of distinct histone tails carrying cooccurring PTMs. We measured temporally distinct combinatorial PTM profiles during C. elegans development. We show that the doubly modified form H3K23me3K27me3, which is rare or nonexistent in mammals, is the most abundant PTM in all stages of C. elegans lifecycle. The abundance of H3K23me3 increased during development and it was mutually exclusive of the active marks H3K18ac, R26me1, and R40me1, suggesting a role for H3K23me3 in silent chromatin. We observed distinct PTM profiles for normal L1 larvae and for L1-postdauer larvae, or L4 and L4 postdauer, suggesting that histone PTMs mediate an epigenetic memory 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. All MS data have been deposited in the ProteomeXchange with identifier PXD002525 (http://proteomecentral.proteomexchange.org/dataset/PXD002525). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effects of space radiation and microgravity on miRNA expression profile in Caenorhabditis elegans

    Science.gov (United States)

    Xu, Dan; Sun, Yeqing; Lei, Huang; Gao, Ying

    2012-07-01

    Living organisms experience a shock and subsequent adaption when they are subjected to space radiation and microgravity during spaceflight. Such changes have been already documented for some biological consequences including skeletal muscle alterations, reduced immune function and bone loss. Recent advancement in the field of molecular biology has demonstrated that small non-coding microRNA (miRNA) can have a broad effect on gene expression networks, and play a key role in cellular response to environmental stresses. However, little is known about how radiation exposure and altered gravity affect miRNA expression. In the present study, we explored the changes in expression of miRNA and related genes from Caenorhabditis elegans (C.elegans) flown on spaceflight. We used wild-type (N2) and dys-1 mutant (deletion of dys-1) stains of C.elegans, which were cultured to Dauer stage and transferred to special SIMbox in the experiment container. These worms taken by Shenzhou VIII spacecraft experienced the 16.5-day shuttle spaceflight. During spaceflight, they suffered space radiation and underwent static zero gravity (microgravity) or imitated earth gravity (1g) in the rotating condition. In contrast, these worms live under static earth gravity (1g) in ground-based controls. To evaluate the effects of space radiation and microgravity on miRNA expression profile, we performed miRNA microarray expression analysis and found that a set of miRNAs in N2 groups were significantly upregulated or downregualted in radiation and microgravity conditions. Among these altered miRNAs, there are two up-regulated and four down-regulated miRNAs in space radiation conditions; one down-regulated miRNAs in microgravity condition. Expression of several miRNAs in N2 groups was only changed significantly in the imitated earth gravity (1g) conditions, presenting these altered miRNAs were affected by radiation exposure alone. Notably, dys-1 mutant is not sensitive to altered gravity due to muscle

  10. Three distinct amine receptors operating at different levels within the locomotory circuit are each essential for the serotonergic modulation of chemosensation in Caenorhabditis elegans

    OpenAIRE

    Harris, Gareth P.; Hapiak, Vera M.; Wragg, Rachel T.; Miller, Sarah B.; Hughes, Lindsay J.; Hobson, Robert J.; Steven, Robert; Bamber, Bruce; Komuniecki, Richard W.

    2009-01-01

    Serotonin modulates behavioral plasticity in both vertebrates and invertebrates and in Caenorhabditis elegans regulates key behaviors, including locomotion, aversive learning and olfaction through at least four different 5-HT receptors. In the present study, we examined the serotonergic stimulation of aversive responses to dilute octanol in animals containing null alleles of these 5-HT receptors. Both ser-1 and mod-1 null animals failed to increase sensitivity to dilute octanol on food/5-HT, ...

  11. Application of reinforced frontal affinity chromatography and advanced processing procedure to the study of the binding property of a Caenorhabditis elegans galectin.

    Science.gov (United States)

    Arata, Y; Hirabayashi, J; Kasai, K I

    2001-01-05

    Frontal affinity chromatography is a very useful and simple method to analyze molecular interactions between an analyte and an immobilized ligand by calculating the extent of "retardation" of the elution front. We developed a very simple and efficient data-processing procedure that enables the measurement of very small differences in retardation with precision. This procedure was successfully applied to comparison of the binding properties of recombinant C. elegans galectins for their ligand.

  12. The Caenorhabditis elegans rsd-2 and rsd-6 Genes Are Required for Chromosome Functions During Exposure to Unfavorable Environments

    OpenAIRE

    Han, Wang; Sundaram, Prema; Kenjale, Himanshu; Grantham, James; Timmons, Lisa

    2008-01-01

    In Caenorhabditis elegans, exogenous dsRNA can elicit systemic RNAi, a process that requires the function of many genes. Considering that the activities of many of these genes are also required for normal development, it is surprising that exposure to high concentrations of dsRNA does not elicit adverse consequences to animals. Here, we report inducible phenotypes in attenuated C. elegans strains reared in environments that include nonspecific dsRNA and elevated temperature. Under these condi...

  13. Caenorhabditis elegans mutants having altered preference of chemotaxis behavior during simultaneous presentation of two chemoattractants.

    Science.gov (United States)

    Lin, Lin; Wakabayashi, Tokumitsu; Oikawa, Tomohiro; Sato, Tsutomu; Ogurusu, Tarou; Shingai, Ryuzo

    2006-11-01

    Upon presentation of two distinct chemoattractants such as sodium acetate and diacetyl simultaneously, the nematode Caenorhabditis elegans was preferentially attracted by one of these chemoattractants. We isolated two mutants having altered preference of chemotaxis behavior toward simultaneous presentation of sodium acetate and diacetyl. The chep-1(qr1) (CHEmosensory Preference) mutant preferred sodium acetate to diacetyl, while the chep-2(qr2) mutant preferred diacetyl to sodium acetate in simultaneous presentation of these chemoattractants. The chemotaxis behavior of chep-2(qr2) mutant in simultaneous presentation suggests a function of chep-2 gene products within the chemosensory informational integration pathway as well as in the chemosensory pathway.

  14. Computer assisted assembly of connectomes from electron micrographs: application to Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Meng Xu

    Full Text Available A rate-limiting step in determining a connectome, the set of all synaptic connections in a nervous system, is extraction of the relevant information from serial electron micrographs. Here we introduce a software application, Elegance, that speeds acquisition of the minimal dataset necessary, allowing the discovery of new connectomes. We have used Elegance to obtain new connectivity data in the nematode worm Caenorhabditis elegans. We analyze the accuracy that can be obtained, which is limited by unresolvable ambiguities at some locations in electron microscopic images. Elegance is useful for reconstructing connectivity in any region of neuropil of sufficiently small size.

  15. 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.

  16. Reduction in chromosome mobility accompanies nuclear organization during early embryogenesis in Caenorhabditis elegans.

    Science.gov (United States)

    Arai, Ritsuko; Sugawara, Takeshi; Sato, Yuko; Minakuchi, Yohei; Toyoda, Atsushi; Nabeshima, Kentaro; Kimura, Hiroshi; Kimura, Akatsuki

    2017-06-16

    In differentiated cells, chromosomes are packed inside the cell nucleus in an organised fashion. In contrast, little is known about how chromosomes are packed in undifferentiated cells and how nuclear organization changes during development. To assess changes in nuclear organization during the earliest stages of development, we quantified the mobility of a pair of homologous chromosomal loci in the interphase nuclei of Caenorhabditis elegans embryos. The distribution of distances between homologous loci was consistent with a random distribution up to the 8-cell stage but not at later stages. The mobility of the loci was significantly reduced from the 2-cell to the 48-cell stage. Nuclear foci corresponding to epigenetic marks as well as heterochromatin and the nucleolus also appeared around the 8-cell stage. We propose that the earliest global transformation in nuclear organization occurs at the 8-cell stage during C. elegans embryogenesis.

  17. Nanoscale imaging and characterization of Caenorhabditis elegans epicuticle using atomic force microscopy.

    Science.gov (United States)

    Fakhrullina, Gölnur; Akhatova, Farida; Kibardina, Maria; Fokin, Denis; Fakhrullin, Rawil

    2017-02-01

    Here we introduce PeakForce Tapping non-resonance atomic force microscopy for imaging and nanomechanical mapping of Caenorhabditis elegans nematodes. The animals were imaged both in air and water at nanoscale resolution. Layer-by-layer glass surface modification was employed to secure the worms for imaging in water. Microtopography of head region, annuli, furrows, lateral alae and tail region was visualized. Analysis of nanoscale surface features obtained during AFM imaging of three larval and adult hermaphrodite nematodes in natural environment allowed for numerical evaluation of annuli periodicity, furrows depth and annuli roughness. Nanomechanical mapping of surface deformation, Young modulus and adhesion confirms that the mechanical properties of the nematode cuticle are non-uniform. Overall, PeakForce Tapping AFM is a robust and simple approach applicable for nanoscale three-dimensional imaging and characterization of C. elegans nematodes. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. A novel dominant transformer allele of the sex-determining gene her-1 of Caenorhabditis elegans.

    Science.gov (United States)

    Trent, C; Wood, W B; Horvitz, H R

    1988-09-01

    We have characterized a novel dominant allele of the sex-determining gene her-1 of Caenorhabditis elegans. This allele, called n695, results in the incomplete transformation of XX animals into phenotypic males. Previously characterized recessive her-1 alleles transform XO animals into phenotypic hermaphrodites. We have identified five new recessive her-1 mutations as intragenic suppressors of n695. Three of these suppressors are weak, temperature-sensitive alleles. We show that the recessive her-1 mutations are loss-of-function alleles, and that the her-1(n695) mutation results in a gain-of-function at the her-1 locus. The existence of dominant and recessive alleles that cause opposite phenotypic transformations demonstrates that the her-1 gene acts to control sexual identity in C. elegans.

  19. Nano-silver induces dose-response effects on the nematode Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Ellegaard-Jensen, Lea; Alstrup Jensen, Keld; Johansen, Anders

    2012-01-01

    Toxicity of nano-formulated silver to eukaryotes was assessed by exposing nematodes (Caenorhabditis elegans) to two types of silver nanoparticles (AgNPs): with average primary particle diameters of 1 nm (AgNP1) and 28 nm (AgNP28, PVP coated), respectively. Tests were performed with and without...... adverse dose-response effects and mortality on C. elegans. LC50 for AgNP28 was lower than for AgNP1 and, hence, at the present test conditions the PVP-coated AgNP28 was more toxic than AgNP1. Including E. coil in the test medium as a food source increased AgNPs toxicity towards nematodes compared to when...

  20. OpenWorm: an open-science approach to modelling Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Balazs eSzigeti

    2014-11-01

    Full Text Available OpenWorm is an international collaboration with the aim of understanding how the behaviour of Caenorhabditis elegans (C. elegans emerges through the underlying biophysical processes. The project has developed a modular simulation engine to create computational models of the worm. The modularity of the engine makes it possible to easily modify the model, incorporate new experimental data and test hypotheses. The modelling framework incorporates both biophysical neuronal simulations and a novel fluid-dynamics-based soft-tissue simulation for physical environment-body interactions. The project's open-science approach is aimed at overcoming the difficulties of integrative modelling within a traditional academic environment. In this article the rationale is presented for creating the OpenWorm collaboration, the tools and resources developed thus far are outlined and the unique challenges associated with the project are discussed.

  1. Control of neuropeptide expression by parallel activity-dependent pathways in caenorhabditis elegans

    DEFF Research Database (Denmark)

    Rojo Romanos, Teresa; Petersen, Jakob Gramstrup; Pocock, Roger

    2017-01-01

    GMP regulation by GCY-9 and the PDE-1 phosphodiesterase controls BAG expression of a FMRFamide-related neuropeptide FLP-19 reporter (flp-19::GFP). This regulation is specific for CO 2 -sensing function of the BAG neurons, as loss of oxygen sensing function does not affect flp-19::GFP expression. We also found...... that expression of flp-19::GFP is controlled in parallel to GCY-9 by the activity-dependent transcription factor CREB (CRH-1) and the cAMP-dependent protein kinase (KIN-2) signaling pathway. We therefore show that two parallel pathways regulate neuropeptide gene expression in the BAG sensory neurons: the ability......Monitoring of neuronal activity within circuits facilitates integrated responses and rapid changes in behavior. We have identified a system in Caenorhabditis elegans where neuropeptide expression is dependent on the ability of the BAG neurons to sense carbon dioxide. In C. Elegans, CO 2 sensing...

  2. 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.

  3. Tyrosylprotein sulfotransferase regulates collagen secretion in Caenorhabditis elegans.

    Science.gov (United States)

    Kim, Tai Hoon; Kim, Do Hyun; Nam, Hyung Wook; Park, Sang Yoon; Shim, Jaegal; Cho, Jin Won

    2010-04-01

    The sulfation of tyrosine residues is an important post-translational modification involved in the regulation of protein function. We examined the activity of worm tyrosylprotein sulfotransferase (TPST-1) on a typical cuticle collagen, ROL-6, in C. elegans. We verified that TPST-1 sulfates three tyrosine residues of ROL-6 in vitro. We found that these tyrosine residues are important for the secretion of ROL-6::GFP. Mutant ROL-6::GFP proteins that contain more than two substitutions of the target tyrosine residues are severely deficient in cuticle localization. Consistently, knock down of tpst-1 blocked the cuticle localization of ROL-6::GFP. Therefore, the sulfation of ROL-6 by TPST-1 is critical for the proper localization of ROL-6. We also confirmed that worm TPST-1 is localized to the trans-Golgi network (TGN). Our results indicate that TPST-1 regulates cuticle organization by promoting the transport of ROL-6 from the TGN to the cuticle.

  4. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Malate and fumarate extend lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Edwards, Clare B; Copes, Neil; Brito, Andres G; Canfield, John; Bradshaw, Patrick C

    2013-01-01

    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.

  6. 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.

  7. Beyond Traditional Antimicrobials: A Caenorhabditis elegans Model for Discovery of Novel Anti-infectives

    Science.gov (United States)

    Kong, Cin; Eng, Su-Anne; Lim, Mei-Perng; Nathan, Sheila

    2016-01-01

    The spread of antibiotic resistance amongst bacterial pathogens has led to an urgent need for new antimicrobial compounds with novel modes of action that minimize the potential for drug resistance. To date, the development of new antimicrobial drugs is still lagging far behind the rising demand, partly owing to the absence of an effective screening platform. Over the last decade, the nematode Caenorhabditis elegans has been incorporated as a whole animal screening platform for antimicrobials. This development is taking advantage of the vast knowledge on worm physiology and how it interacts with bacterial and fungal pathogens. In addition to allowing for in vivo selection of compounds with promising anti-microbial properties, the whole animal C. elegans screening system has also permitted the discovery of novel compounds targeting infection processes that only manifest during the course of pathogen infection of the host. Another advantage of using C. elegans in the search for new antimicrobials is that the worm itself is a source of potential antimicrobial effectors which constitute part of its immune defense response to thwart infections. This has led to the evaluation of effector molecules, particularly antimicrobial proteins and peptides (APPs), as candidates for further development as therapeutic agents. In this review, we provide an overview on use of the C. elegans model for identification of novel anti-infectives. We highlight some highly potential lead compounds obtained from C. elegans-based screens, particularly those that target bacterial virulence or host defense to eradicate infections, a mechanism distinct from the action of conventional antibiotics. We also review the prospect of using C. elegans APPs as an antimicrobial strategy to treat infections. PMID:27994583

  8. Evaluation of the antioxidant property and effects in Caenorhabditis elegans of Xiangxi flavor vinegar, a Hunan local traditional vinegar.

    Science.gov (United States)

    Huang, Run-Ting; Huang, Qing; Wu, Gen-Liang; Chen, Chun-Guang; Li, Zong-Jun

    Xiangxi flavor vinegar (XV) is one of Hunan Province's traditional fermented vinegars. It is produced from herb, rice, and spring water with spontaneous liquid-state fermentation techniques. In this study, we investigated the antioxidant property of XV by analyzing its antioxidant compounds, its free radical scavenging property in vitro and in vivo, and its effects on antioxidant enzyme activity and apoptosis in Caenorhabditis elegans. The results showed that XV is rich in antioxidants. In particular, ligustrazine reached 6.431 μg/ml. The in vitro 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH(•)), hydroxyl radical ((•)OH), and superoxide anion radical (O2(•-)) scavenging rates of XV were 95.85%, 97.22%, and 63.33%, respectively. The reactive oxygen species (ROS) content in XV-treated C. elegans decreased significantly (Pantioxidants and scavenges radicals in vitro efficiently. XV inhibits apoptosis in C. elegans probably by scavenging ROS and increasing the activities of its antioxidant enzymes.

  9. 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'. © 2016 The Author(s).

  10. 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. Copyright © 2014 by the Genetics Society of America.

  11. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Humidity sensation requires both mechanosensory and thermosensory pathways in Caenorhabditis elegans.

    Science.gov (United States)

    Russell, Joshua; Vidal-Gadea, Andrés G; Makay, Alex; Lanam, Carolyn; Pierce-Shimomura, Jonathan T

    2014-06-03

    All terrestrial animals must find a proper level of moisture to ensure their health and survival. The cellular-molecular basis for sensing humidity is unknown in most animals, however. We used the model nematode Caenorhabditis elegans to uncover a mechanism for sensing humidity. We found that whereas C. elegans showed no obvious preference for humidity levels under standard culture conditions, worms displayed a strong preference after pairing starvation with different humidity levels, orienting to gradients as shallow as 0.03% relative humidity per millimeter. Cell-specific ablation and rescue experiments demonstrate that orientation to humidity in C. elegans requires the obligatory combination of distinct mechanosensitive and thermosensitive pathways. The mechanosensitive pathway requires a conserved DEG/ENaC/ASIC mechanoreceptor complex in the FLP neuron pair. Because humidity levels influence the hydration of the worm's cuticle, our results suggest that FLP may convey humidity information by reporting the degree that subcuticular dendritic sensory branches of FLP neurons are stretched by hydration. The thermosensitive pathway requires cGMP-gated channels in the AFD neuron pair. Because humidity levels affect evaporative cooling, AFD may convey humidity information by reporting thermal flux. Thus, humidity sensation arises as a metamodality in C. elegans that requires the integration of parallel mechanosensory and thermosensory pathways. This hygrosensation strategy, first proposed by Thunberg more than 100 y ago, may be conserved because the underlying pathways have cellular and molecular equivalents across a wide range of species, including insects and humans.

  13. Specific alpha- and beta-tubulin isotypes optimize the functions of sensory Cilia in Caenorhabditis elegans.

    Science.gov (United States)

    Hurd, Daryl D; Miller, Renee M; Núñez, Lizbeth; Portman, Douglas S

    2010-07-01

    Primary cilia have essential roles in transducing signals in eukaryotes. At their core is the ciliary axoneme, a microtubule-based structure that defines cilium morphology and provides a substrate for intraflagellar transport. However, the extent to which axonemal microtubules are specialized for sensory cilium function is unknown. In the nematode Caenorhabditis elegans, primary cilia are present at the dendritic ends of most sensory neurons, where they provide a specialized environment for the transduction of particular stimuli. Here, we find that three tubulin isotypes--the alpha-tubulins TBA-6 and TBA-9 and the beta-tubulin TBB-4--are specifically expressed in overlapping sets of C. elegans sensory neurons and localize to the sensory cilia of these cells. Although cilia still form in mutants lacking tba-6, tba-9, and tbb-4, ciliary function is often compromised: these mutants exhibit a variety of sensory deficits as well as the mislocalization of signaling components. In at least one case, that of the CEM cephalic sensory neurons, cilium architecture is disrupted in mutants lacking specific ciliary tubulins. While there is likely to be some functional redundancy among C. elegans tubulin genes, our results indicate that specific tubulins optimize the functional properties of C. elegans sensory cilia.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Antioxidative Activities of Both Oleic Acid and Camellia tenuifolia Seed Oil Are Regulated by the Transcription Factor DAF-16/FOXO in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Chia-Cheng Wei

    Full Text Available Tea seed oil is a high quality edible oil, yet lacking sufficient scientific evidences to support the nutritional and medical purposes. We identified major and minor components in Camellia tenuifolia seed oil and investigated the antioxidative activity and its underlying mechanisms in Caenorhabditis elegans.The results showed that the major constitutes in C. tenuifolia seed oil were unsaturated fatty acids (~78.4%. Moreover, two minor compounds, β-amyrin and β-sitosterol, were identified and their antioxidative activity was examined. We found that oleic acid was the major constitute in C. tenuifolia seed oil and plays a key role in the antioxidative activity of C. tenuifolia seed oil in C. elegans.This study found evidences that the transcription factor DAF-16/FOXO was involved in both oleic acid- and C. tenuifolia seed oil-mediated oxidative stress resistance in C. elegans. This study suggests the potential of C. tenuifolia seed oil as nutrient or functional foods.

  16. Deep SAGE analysis of the Caenorhabditis elegans transcriptome.

    Science.gov (United States)

    Ruzanov, Peter; Riddle, Donald L

    2010-06-01

    We employed the Tag-seq technique to generate global transcription profiles for different strains and life stages of the nematode C. elegans. Tag-seq generates cDNA tags as does Serial Analysis of Gene Expression (SAGE), but the method yields a much larger number of tags, generating much larger data sets than SAGE. We examined differences in the performance of SAGE and Tag-seq by comparing gene expression data for 13 pairs of libraries. We identified genes for which expression was consistently changed in long-lived worms. Additional genes emerged in the deeper Tag-seq profiles, including several 'signature' genes found among those zup-regulated in long-lived dauer larvae (cki-1, aak-2 and daf-16). Fifty to sixty percent of the genes differentially expressed in daf-2(-) versus daf-2(+) adults had fragmentary or no functional annotation, suggesting the involvement of as yet unstudied pathways in aging. We were able to distinguish between changes in gene expression associated with altered genotype or altered growth conditions. We found 62 cases of possible mRNA isoform switching in the 13 Tag-seq libraries, whereas the 13 SAGE libraries allowed detection of only 15 such occurrences. We observed strong expression of anti-sense transcripts for several mitochondrial genes, but nuclear anti-sense transcripts were neither abundant nor consistently expressed among the libraries.

  17. Caenorhabditis elegans glutamylating enzymes function redundantly in male mating

    Directory of Open Access Journals (Sweden)

    Daniel G. Chawla

    2016-09-01

    Full Text Available 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.

  18. Physiological response of the nematode Caenorhabditis elegans exposed to binary mixture of uranium and cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Margerit, A.; Gilbin, R. [French Institute for Radiological Protection and Nuclear Safety - IRSN (France); Gomez, E. [Universite Montpellier 1 (France)

    2014-07-01

    Both uranium (U) and cadmium (Cd) are natural ubiquitous substances whose occurrence may be magnified in the vicinity of some Nuclear Fuel Cycle Facility (NFCF) (e.g. uranium mining area) or intensive farming areas. Natural U is a mainly chemo-toxic radioelement, with a slight radio-toxic activity, while Cd is a fully chemo-toxic trace metal. Due to their possible co-occurrence, the study of their combined effects on ecosystems may be of interest in a risk assessment perspective. MixTox tool is a simple descriptive model commonly used to study the effects of chemical mixtures. It relies on dose response, concentration addition and response addition concepts to describe combined toxicant effects and identify possible Synergistic/Antagonistic - Constant/Dose-level/Dose ratio dependent - interactions. In the present study, toxicity of binary mixture of U and Cd was assessed on physiological parameters, maximal length and brood size, in the soil nematode Caenorhabditis elegans. A 49 condition fractional factorial design was used with U and Cd concentrations ranging from 0.95 to 1.3 mM and 0.006 to 0.04 mM, respectively. Dose response curves obtained for U and Cd on maximal length and brood size were consistent with published data. Using MixTox tool, the best description of these endpoints was met with the response addition concept and the dose-ratio dependent interaction model. A significant antagonism was identified when Cd toxicity is preponderant in the mixture and was confirmed with experimental observations. On the other hand, no significant interaction could be identified when U toxicity was preponderant in the mixture. Interaction between the two chemicals may occur during the exposure, the toxicokinetics and/or during the toxico-dynamic phases. Based on the results of this study, a probable hypothesis would be that U, whose toxicity is in the mM range, reduces bioaccumulation of Cd, whose toxicity is in the range of 10 μM. A bioaccumulation assay of U and Cd

  19. 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…

  20. The general control nonderepressible-2 kinase mediates stress response and longevity induced by target of rapamycin inactivation in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Rousakis, Aris; Vlassis, Arsenios; Vlanti, Anna

    2013-01-01

    The general control nonderepressible 2 (GCN2) kinase is a nutrient-sensing pathway that responds to amino acids deficiency and induces a genetic program to effectively maintain cellular homeostasis. Here we established the conserved role of Caenorhabditis elegans GCN-2 under amino acid limitation...

  1. 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

  2. Rosmarinus officinalis L. increases Caenorhabditis elegans stress resistance and longevity in a DAF-16, HSF-1 and SKN-1-dependent manner.

    Science.gov (United States)

    Zamberlan, D C; Amaral, G P; Arantes, L P; Machado, M L; Mizdal, C R; Campos, M M A; Soares, F A A

    2016-08-01

    Improving overall health and quality of life, preventing diseases and increasing life expectancy are key concerns in the field of public health. The search for antioxidants that can inhibit oxidative damage in cells has received a lot of attention. Rosmarinus officinalis L. represents an exceptionally rich source of bioactive compounds with pharmacological properties. In the present study, we explored the effects of the ethanolic extract of R. officinalis (eeRo) on stress resistance and longevity using the non-parasitic nematode Caenorhabditis elegans as a model. We report for the first time that eeRo increased resistance against oxidative and thermal stress and extended C. elegans longevity in an insulin/IGF signaling pathway-dependent manner. These data emphasize the eeRo beneficial effects on C. elegans under stress.

  3. Triclosan (TCS) and triclocarban (TCC) induce systemic toxic effects in a model organism the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Lenz, Katrina A; Pattison, Claire; Ma, Hongbo

    2017-12-01

    The broad application of triclosan (TCS) and triclocarban (TCC) as antimicrobials in household and personal care products has led to the concerns regarding their human health risk and environmental impact. Although many studies have examined the toxicological effects of these compounds to a wide range of aquatic organisms from algae to fish, their potential toxicity to an important model organism the nematode Caenorhabditis elegans has never been systematically investigated. Here we assessed the toxicological effects of TCS and TCC in C. elegans using endpoints from organismal to molecular levels, including lethality, reproduction, lifespan, hatching, germline toxicity, and oxidative stress. L4 stage or young adult worms were exposed to TCS or TCC and examined using above-mentioned endpoints. Both TCS and TCC showed acute toxicity to C. elegans, with 24-h LC50s of 3.65 (95% CI: 3.15, 4.3) mg/L and 0.91 (95% CI: 0.47, 1.53) mg/L, respectively. TCS at 0.1-2 mg/L and TCC at 0.01-0.5 mg/L, respectively, induced concentration dependent reduction in the worm's reproduction, lifespan, and delay in hatching. Using a DAF-16:GFP transgenic strain, we found both compounds induced oxidative stress in the worm, indicated by the relocalization of DAF-16:GFP from cytoplasm to the nucleus upon exposure. Germline toxicity of the two compounds was also demonstrated using a xol-1:GFP transgenic strain. These findings suggest that TCS and TCC induce systemic toxic effects in C. elegans. Further studies are needed to elucidate the potential mechanisms of toxicity of these antimicrobials in the model organism, especially their potential endocrine disruption effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. 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

  5. elt-2, a second GATA factor from the nematode Caenorhabditis elegans.

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    Hawkins, M G; McGhee, J D

    1995-06-16

    We have previously shown that a tandem pair of (A/T)GATA(A/G) sequences in the promoter region of the Caenorhabditis elegans gut esterase gene (ges-1) controls the tissue specificity of ges-1 expression in vivo. The ges-1 GATA region was used as a probe to screen a C. elegans cDNA expression library, and a gene for a new C. elegans GATA-factor (named elt-2) was isolated. The longest open reading frame in the elt-2 cDNA codes for a protein of M(r) 47,000 with a single zinc finger domain, similar (approximately 75% amino acid identity) to the C-terminal fingers of all other two-fingered GATA factors isolated to date. A similar degree of relatedness is found with the single-finger DNA binding domains of GATA factors identified in invertebrates. An upstream region in the ELT-2 protein with the sequence C-X2-C-X16-C-X2-C has some of the characteristics of a zinc finger domain but is highly diverged from the zinc finger domains of other GATA factors. The elt-2 gene is expressed as an SL1 trans-spliced message, which can be detected at all stages of development except oocytes; however, elt-2 message levels are 5-10-fold higher in embryos than in other stages. The genomic clone for elt-2 has been characterized and mapped near the center of the C. elegans X chromosome, ELT-2 protein, produced by in vitro transcription-translation, binds to ges-1 GATA-containing oligonucleotides similar to a factor previously identified in C. elegans embryo extracts, both as assayed by electrophoretic migration and by competition with wild type and mutant oligonucleotides. However, there is as yet no direct evidence that elt-2 does or does not control ges-1.

  6. Molecular signals regulating translocation and toxicity of graphene oxide in the nematode Caenorhabditis elegans

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    Wu, Qiuli; Zhao, Yunli; Li, Yiping; Wang, Dayong

    2014-09-01

    Both in vitro and in vivo studies have demonstrated the toxic effects of graphene oxide (GO). However, the molecular basis for the translocation and toxicity of GO is still largely unclear. In the present study, we employed an in vivo Caenorhabditis elegans assay system to identify molecular signals involved in the control of the translocation and toxicity of GO. We identified 7 genes whose mutations altered both the translocation and toxicity of GO. Mutations of the hsp-16.48, gas-1, sod-2, sod-3, and aak-2 genes caused greater GO translocation into the body and toxic effects on both primary and secondary targeted organs compared with wild type; however, mutations of the isp-1 and clk-1 genes resulted in significantly decreased GO translocation into the body and toxicity on both primary and secondary targeted organs compared with wild-type. Moreover, mutations of the hsp-16.48, gas-1, sod-2, sod-3, and aak-2 genes caused increased intestinal permeability and prolonged mean defecation cycle length in GO-exposed nematodes, whereas mutations of the isp-1 and clk-1 genes resulted in decreased intestinal permeability in GO-exposed nematodes. Therefore, for the underlying mechanism, we hypothesize that both intestinal permeability and defecation behavior may have crucial roles in controlling the functions of the identified molecular signals. The molecular signals may further contribute to the control of transgenerational toxic effects of GO. Our results provide an important insight into understanding the molecular basis for the in vivo translocation and toxicity of GO.Both in vitro and in vivo studies have demonstrated the toxic effects of graphene oxide (GO). However, the molecular basis for the translocation and toxicity of GO is still largely unclear. In the present study, we employed an in vivo Caenorhabditis elegans assay system to identify molecular signals involved in the control of the translocation and toxicity of GO. We identified 7 genes whose mutations

  7. Putative calcium-binding domains of the Caenorhabditis elegans BK channel are dispensable for intoxication and ethanol activation.

    Science.gov (United States)

    Davis, S J; Scott, L L; Ordemann, G; Philpo, A; Cohn, J; Pierce-Shimomura, J T

    2015-07-01

    Alcohol modulates the highly conserved, voltage- and calcium-activated potassium (BK) channel, which contributes to alcohol-mediated behaviors in species from worms to humans. Previous studies have shown that the calcium-sensitive domains, RCK1 and the Ca(2+) bowl, are required for ethanol activation of the mammalian BK channel in vitro. In the nematode Caenorhabditis elegans, ethanol activates the BK channel in vivo, and deletion of the worm BK channel, SLO-1, confers strong resistance to intoxication. To determine if the conserved RCK1 and calcium bowl domains were also critical for intoxication and basal BK channel-dependent behaviors in C. elegans, we generated transgenic worms that express mutated SLO-1 channels predicted to have the RCK1, Ca(2+) bowl or both domains rendered insensitive to calcium. As expected, mutating these domains inhibited basal function of SLO-1 in vivo as neck and body curvature of these mutants mimicked that of the BK null mutant. Unexpectedly, however, mutating these domains singly or together in SLO-1 had no effect on intoxication in C. elegans. Consistent with these behavioral results, we found that ethanol activated the SLO-1 channel in vitro with or without these domains. By contrast, in agreement with previous in vitro findings, C. elegans harboring a human BK channel with mutated calcium-sensing domains displayed resistance to intoxication. Thus, for the worm SLO-1 channel, the putative calcium-sensitive domains are critical for basal in vivo function but unnecessary for in vivo ethanol action. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  8. Anti-inflammatory Lactobacillus rhamnosus CNCM I-3690 strain protects against oxidative stress and increases lifespan in Caenorhabditis elegans.

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    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.

  9. Novel Mutations in Synaptic Transmission Genes Suppress Neuronal Hyperexcitation in Caenorhabditis elegans

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    Katherine A. McCulloch

    2017-07-01

    Full Text Available Acetylcholine (ACh receptors (AChR regulate neural circuit activity in multiple contexts. In humans, mutations in ionotropic acetylcholine receptor (iAChR genes can cause neurological disorders, including myasthenia gravis and epilepsy. In Caenorhabditis elegans, iAChRs play multiple roles in the locomotor circuit. The cholinergic motor neurons express an ACR-2-containing pentameric AChR (ACR-2R comprised of ACR-2, ACR-3, ACR-12, UNC-38, and UNC-63 subunits. A gain-of-function mutation in the non-α subunit gene acr-2 [acr-2(gf] causes defective locomotion as well as spontaneous convulsions. Previous studies of genetic suppressors of acr-2(gf have provided insights into ACR-2R composition and assembly. Here, to further understand how the ACR-2R regulates neuronal activity, we expanded the suppressor screen for acr-2(gf-induced convulsions. The majority of these suppressor mutations affect genes that play critical roles in synaptic transmission, including two novel mutations in the vesicular ACh transporter unc-17. In addition, we identified a role for a conserved major facilitator superfamily domain (MFSD protein, mfsd-6, in regulating neural circuit activity. We further defined a role for the sphingosine (SPH kinase (Sphk sphk-1 in cholinergic neuron activity, independent of previously known signaling pathways. Overall, the genes identified in our study suggest that optimal modulation of synaptic activity is balanced by the differential activities of multiple pathways, and the novel alleles provide valuable reagents to further dissect neuronal mechanisms regulating the locomotor circuit.

  10. In silico analysis of the binding of anthelmintics to Caenorhabditis elegans P-glycoprotein 1

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    Marion A. David

    2016-12-01

    Full Text Available Macrocyclic lactones (ML are important anthelmintics used in animals and humans against parasite nematodes, but their therapeutic success is compromised by the spread of ML resistance. Some ABC transporters, such as p-glycoproteins (Pgps, are selected and overexpressed in ML-resistant nematodes, supporting a role for some drug efflux proteins in ML resistance. However, the role of such proteins in ML transport remains to be clarified at the molecular level. Recently, Caenorhabditis elegans Pgp-1 (Cel-Pgp-1 has been crystallized, and its drug-modulated ATPase function characterized in vitro revealed Cel-Pgp-1 as a multidrug transporter. Using this crystal structure, we have developed an in silico drug docking model in order to study the binding of ML and other anthelmintic drugs to Cel-Pgp-1. All tested ML bound with high affinity in a unique site, within the inner chamber of the protein, supporting that ML may be transported by Cel-Pgp-1. Interestingly, interacting residues delineate a ML specific fingerprint involving H-bonds, including T1028. In particular, benzofurane and spiroketal moieties bound to specific sub-sites. When compared with the aglycone ML, such as moxidectin and ivermectin aglycone, avermectin anthelmintics have significant higher affinity for Cel-Pgp-1, likely due to the sugar substituent(s that bind to a specific area involving H-bonds at Y771. Triclabendazole, closantel and emodepside bound with good affinities to different sub-sites in the inner chamber, partially overlapping with the ML binding site, suggesting that they could compete for Cel-Pgp-1-mediated ML transport. In conclusion, this work provides novel information on the role of nematode Pgps in transporting anthelmintics, and a valuable tool to predict drug-drug interactions and to rationally design new competitive inhibitors of clinically-relevant nematode Pgps, to improve anthelmintic therapeutics.

  11. Dynamically-expressed prion-like proteins form a cuticle in the pharynx of Caenorhabditis elegans

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    Julia B. George-Raizen

    2014-10-01

    Full Text Available In molting animals, a cuticular extracellular matrix forms the first barrier to infection and other environmental insults. In the nematode Caenorhabditis elegans there are two types of cuticle: a well-studied collagenous cuticle lines the body, and a poorly-understood chitinous cuticle lines the pharynx. In the posterior end of the pharynx is the grinder, a tooth-like cuticular specialization that crushes food prior to transport to the intestine for digestion. We here show that the grinder increases in size only during the molt. To gain molecular insight into the structure of the grinder and pharyngeal cuticle, we performed a microarray analysis to identify mRNAs increased during the molt. We found strong transcriptional induction during the molt of 12 of 15 previously identified abu genes encoding Prion-like (P glutamine (Q and asparagine (N rich PQN proteins, as well as 15 additional genes encoding closely related PQN proteins. abu/pqn genes, which we name the abu/pqn paralog group (APPG genes, were expressed in pharyngeal cells and the proteins encoded by two APPG genes we tested localized to the pharyngeal cuticle. Deleting the APPG gene abu-14 caused abnormal pharyngeal cuticular structures and knocking down other APPG genes resulted in abnormal cuticular function. We propose that APPG proteins promote the assembly and function of a unique cuticular structure. The strong developmental regulation of the APPG genes raises the possibility that such genes would be identified in transcriptional profiling experiments in which the animals' developmental stage is not precisely staged.

  12. Mechanism of silver nanoparticle toxicity is dependent on dissolved silver and surface coating in Caenorhabditis elegans.

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    Yang, Xinyu; Gondikas, Andreas P; Marinakos, Stella M; Auffan, Melanie; Liu, Jie; Hsu-Kim, Heileen; Meyer, Joel N

    2012-01-17

    The rapidly increasing use of silver nanoparticles (Ag NPs) in consumer products and medical applications has raised ecological and human health concerns. A key question for addressing these concerns is whether Ag NP toxicity is mechanistically unique to nanoparticulate silver, or if it is a result of the release of silver ions. Furthermore, since Ag NPs are produced in a large variety of monomer sizes and coatings, and since their physicochemical behavior depends on the media composition, it is important to understand how these variables modulate toxicity. We found that a lower ionic strength medium resulted in greater toxicity (measured as growth inhibition) of all tested Ag NPs to Caenorhabditis elegans and that both dissolved silver and coating influenced Ag NP toxicity. We found a linear correlation between Ag NP toxicity and dissolved silver, but no correlation between size and toxicity. We used three independent and complementary approaches to investigate the mechanisms of toxicity of differentially coated and sized Ag NPs: pharmacological (rescue with trolox and N-acetylcysteine), genetic (analysis of metal-sensitive and oxidative stress-sensitive mutants), and physicochemical (including analysis of dissolution of Ag NPs). Oxidative dissolution was limited in our experimental conditions (maximally 15% in 24 h) yet was key to the toxicity of most Ag NPs, highlighting a critical role for dissolved silver complexed with thiols in the toxicity of all tested Ag NPs. Some Ag NPs (typically less soluble due to size or coating) also acted via oxidative stress, an effect specific to nanoparticulate silver. However, in no case studied here was the toxicity of a Ag NP greater than would be predicted by complete dissolution of the same mass of silver as silver ions.

  13. The role of phospholipid headgroup composition and trehalose in the desiccation tolerance of Caenorhabditis elegans.

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    Abusharkh, Sawsan E; Erkut, Cihan; Oertel, Jana; Kurzchalia, Teymuras V; Fahmy, Karim

    2014-11-04

    Anhydrobiotic organisms have the remarkable ability to lose extensive amounts of body water and survive in an ametabolic state. Distributed to various taxa of life, these organisms have developed strategies to efficiently protect their cell membranes and proteins against extreme water loss. Recently, we showed that the dauer larva of the nematode Caenorhabditis elegans is anhydrobiotic and accumulates high amounts of trehalose during preparation to harsh desiccation (preconditioning). Here, we have used this genetic model to study the biophysical manifestations of anhydrobiosis and show that, in addition to trehalose accumulation, dauer larvae dramatically reduce their phosphatidylcholine (PC) content. The chemical composition of the phospholipids (PLs) has key consequences not only for their interaction with