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Sample records for cunninghamella elegans atcc36112

  1. Metabolism of methoxychlor by Cunninghamella elegans ATCC36112.

    Science.gov (United States)

    Keum, Young Soo; Lee, Youn Hyung; Kim, Jeong-Han

    2009-09-01

    Methoxychlor is considered as pro-estrogen, while some of its metabolites are more potent endocrine disruptors than the parent insecticide. Major activation of methoxychlor is through cytochrome P450-catalyzed demethylation to bisphenol A-like metabolites. Cunninghamella elegans is a well-known fungal species with its strong resemblance of the xenobiotic metabolism of the mammalian system. In this study, the metabolism of methoxychlor was investigated with the corresponding organism. Methoxychlor was rapidly transformed to approximately 11 metabolites in phase I metabolism, including oxidation, hydroxylation, and dechlorination. Concentrations of phase I metabolites reached a maximum at 4-6 days and gradually decreased until the end of the experiments. Most metabolites from the phase I reaction were further transformed to sugar conjugates. Approximately 11 or more glucose conjugates were found in culture supernatants and gradually increased, while no glucuronides were observed throughout the experiments. Piperonyl butoxide and chlorpyrifos strongly inhibit the degradation of methoxychlor and concomitant accumulation of metabolites, indicating cytochrome P450 mediated metabolism. Little or no glycosides were detected in chlorpyrifos- and piperonyl butoxide-treated cultures. From the results, Cunninghamella elegans has shown strong similarities of the phase I metabolism of methoxychlor, while the conjugation reaction is different from those of animal metabolism.

  2. Biotransformation of fluorene by the fungus Cunninghamella elegans

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    Pothuluri, J.V.; Freeman, J.P.; Evans, F.E.; Cerniglia, C.E. (Food and Drug Administration, Jefferson, AR (United States))

    1993-06-01

    Fluorene, a tricyclic aromatic hydrocarbon, is formed during the combustion of fossil fuels and is an important pollutant of aquatic ecosystems where it is highly toxic to fish and algae. Few studies on microbial biodegradation of fluorene have been reported. This investigation describes the metabolism of fluorene by the fungus Cunninghamella elegans ATCC 36112 and the identification of major metabolites. 26 refs., 2 figs., 1 tab.

  3. Fungal transformation of fluoranthene. [Cunninghamella elegans

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    Pothuluri, J.V.; Freeman, J.P.; Evans, F.E.; Cerniglia, C.E. (Food and Drug Administration, Jefferson, AR (USA))

    1990-10-01

    The fungus Cunninghamella elegans ATCC 36112 metabolized approximately 80% of the 3-{sup 14}C-labeled fluoranthene (FA) added within 72 h of incubation. C. elegans metabolized FA to trans-2,3-dihydroxy-2,3-dihydrofluoranthene (trans-2,3-dihydrodiol), 8- and 9-hydroxyfluoranthene trans-2,3-dihydrodiol, 3-fluoranthene-{beta}-glucopyranoside, and 3-(8-hydroxyflouranthene)-{beta}-glucopyranoside. These metabolites were separated by thin-layer and reversed-phase high-performance liquid chromatography and identified by {sup 1}H nuclear magnetic resonance, UV, and mass spectral techniques. The major pathway involved hydroxylation to form a glucoside conjugate of 3-hydroxyfluoranthene and a glucoside conjugate of 3,8-dihydroxyfluoranthene which together accounted for 52% of the total ethyl acetate-soluble metabolites. C. elegans initially metabolized FA in the 2,3 position to form fluoranthene trans-2,3-dihydrodiol, which has previously been shown to be a biologically active compound in mammalian and bacterial genotoxicity tests. However, C. elegans formed predominantly glucoside conjugates of the phenolic derivatives of FA, which suggests that this fungus has the potential to detoxify FA.

  4. Biotransformation of furanocoumarins by Cunninghamella elegans

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    Ghada Ismail El-shahat Ali Attia

    2015-06-01

    Full Text Available Biotransformation of Furanocoumarins; psoralen (1, bergapten (2, xanthotoxin (3 and imperatorin (4 was explored by Cunninghamella elegans NRRL 1392, revealing the metabolism of psoralen (1 and bergapten (2 into bergaptol (5, while xanthotoxin (3 and imperatorin (4 were converted into xanthotoxol (6. On the other hand unexpected conversion of xanthotoxin (3 into 3,4 dihydroxanthotoxin (7 occurred. The structure of the isolated pure metabolites was established using physical and spectroscopic techniques including, melting points, IR, 1H NMR, 13C NMR and mass spectroscopy.

  5. Biotransformation of amitriptyline by Cunninghamella elegans.

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    Zhang, D; Evans, F E; Freeman, J P; Duhart, B; Cerniglia, C E

    1995-12-01

    A fungal biotransformation system as an in vitro model for mammalian drug metabolism was investigated. Amitriptyline, a widely used antidepressant, was effectively biotransformed within 72 hr by the filamentous fungus, Cunninghamella elegans. Eight major metabolites in HPLC elution order (11-hydroxyamitriptyline N-oxide, 11-hydroxynortriptyline, 11-hydroxyamitriptyline, 10-hydroxyamitriptyline, 3-hydroxyamitriptyline, 2-hydroxyamitriptyline, nortriptyline, and amitriptyline N-oxide) were produced at estimated molar ratios of 2:1:10:0.6:0.1:1.2.5:0.5, respectively. These metabolites were isolated by HPLC and identified by UV/MS analyses, as well as NMR spectroscopic analysis for most of these metabolites. In some cases, they were also compared with authentic standards. Glucose, culture age, and substrate concentration significantly affected the extent of amitriptyline metabolism. Kinetic studies indicated that nortriptyline and 11-hydroxyamitriptyline were produced as initial major metabolites. The hydroxylated metabolite was excreted from mycelia, but amitriptyline and its N-demethylated metabolite, nortriptyline, were not. An 18O2 labeling experiment showed that the oxygen atoms in 11-hydroxyamitriptyline and 2-hydroxyamitriptyline were derived from molecular oxygen. The cytochrome P450 inhibitors SKF 525-A (1.5 mM), metyrapone (2.0 mM), and 1-aminobenzotriazole (1.0 mM) inhibited the biotransformations of amitriptyline by 50, 75, and 95%, respectively. A microsomal preparation was shown to catalyze the 11-hydroxylation of amitriptyline, which was inhibited by SKF 525-A and carbon monoxide. The similarities of amitriptyline metabolism in C. elegans and in humans and rats are discussed.

  6. One new bufadienolide biotransformed from cinobufagin by Cunninghamella elegans

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    Li Qiao; Yu Zhi Zhou; Huan Chen; Jia Qing Cao; Yue Hu Pei

    2008-01-01

    Cunninghamella elegans has been employed for the biotransformation of cinobufagin (1) to afford one metabolites. The structure of the transformation product has been characterized as 7p,12p-dihydroxylcinobufagin (2). Product 2 is a new compound. In vitro cytotoxic activities of the biotransformation product and the substrate-cinobufagin have been assayed against HeLa; they all showed cytotoxic activities.

  7. Copper influence on polyphosphate metabolism of Cunninghamella elegans Influência de cobre no metabolismo de polifosfato de Cunninghamella elegans

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    Patrícia Mendes de Souza

    2005-12-01

    Full Text Available The aim of this work was to evaluate the physiological aspects of polyphosphate metabolism of Cunninghamella elegans grown in presence of copper. The growth profile was obtained by means of biomass yields, orthophosphate consumption, polyphosphate accumulation and phosphatases activities. The results revealed the influence of copper on the growth, observed by biomass yields. Orthophosphate consumption was faster in cells grown in the presence of copper. The presence of copper in the culture medium induced polyphosphate accumulation. The polyphosphate level was almost constant in the beginning of control culture growth, and could be related to the exponential growth phase. On the other hand, the copper treated cultures exhibited a significant reduction in the polyphosphate levels, indicating an active metabolization of the polymer. Acid phosphatase activity was not detected in the conditions studied, but alkaline phosphatase activity was significantly lower in the treated cultures. The results suggest the potential use of Cunninghamella elegans isolate in bioremediation and biosorption applied to environments polluted by copper.O presente trabalho teve como finalidade avaliar os aspectos fisiológicos do metabolismo do polifosfato em Cunninghamella. elegans cultivada em meio contendo cobre. O perfil de crescimento foi estabelecido em função da produção de biomassa, consumo de ortofosfato, acumulação de polifosfato e atividade das fosfatases. Os resultados obtidos indicaram a influência do metal pesado sobre o crescimento, como observado pelo rendimento da biomassa. O consumo da fonte de fósforo durante as primeiras 24 horas de crescimento na cultura tratada com cobre foi maior que na cultura controle. A acumulação de polifosfato permitiu verificar comportamentos distintos na ausência e presença do metal. A análise do polifosfato celular revelou que, nas amostras tratadas, o polímero é significativamente metabolizado durante o in

  8. Fungal metabolism and detoxification of fluoranthene. [Cunninghamella elegans

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    Pothuluri, J.V.; Heflich, R.H.; Fu, P.P.; Cerniglia, C.E. (Food and Drug Administration, Jefferson, AR (United States))

    1992-03-01

    Five metabolites produced by Cunninghamella elegans from fluoranthene (FA) in biotransformation studies were investigated for mutagenic activity towards Salmonella typhimurium TA100 and TA104. Whereas FA displayed positive, dose-related mutagenic responses in both tester strains in the presence of a rat liver homogenate fraction, 3-FA-{beta}-glucopyranoside, 3-(8-hydroxy-FA)-{beta}-glucopyranoside, FA trans-2,3-dihydrodiol, and 8-hydroxy-FA trans-2,3-dihydrodiol were negative. 9-Hydroxy-FA trans-2,3-dihydrodiol showed a weak positive response in S. typhimurium TA100. Mutagenicity assays performed with samples extracted at 24-h intervals during incubation of C. elegans with FA for 120 h showed that mutagenic activity decreased with time. Comparative studies with rat liver microsomes indicated that FA trans-2,3-dihydrodiol, the previously identified proximal mutagenic metabolite of FA, was the major metabolite. The circular dichroism spectrum of the rat liver microsomal FA trans-2,3-dihydrodiol indicated that is was optically active. In contrast, the circular dichroism spectrum of the fungal FA trans-2,3-dihydrodiol showed no optical activity. These results indicate that C. elegans has the potential to detoxify FA and that the stereochemistry of its trans-2,3-dihydrodiol metabolite reduces its mutagenic potential.

  9. Effects of phosphorus on polyphosphate accumulation by Cunninghamella elegans Efeitos do fósforo sobre a acumulação de polifosfato em Cunninghamella elegans

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    Marcos Antonio Barbosa de Lima

    2003-12-01

    Full Text Available The content of inorganic polyphosphate and the polymeric degree of these compounds were evaluated during the growth of Cunninghamella elegans in medium containing varying orthophosphate (Pi concentrations. For this purpose, a combination of chemical methods for polyphosphate extraction and ultrastructural cytochemistry were used. The orthophosphate and glucose consumption was also determined during the fungal cultivation. At Pi concentrations of 0.5, 2.5 and 0.0 g/L, the maximum amounts of biomass were 3.18, 3.29 and 0.24 g/L, respectively. During growth the cells accumulated Pi from the medium. At three days of growth the biomass consumed up to 100 and 95% of Pi from the media at initial concentrations of 0.5 and 2.5 g/L, respectively. Polyphosphate was observed at different Pi concentrations in medium and at different stages of growth. Polyphosphate was assayed by the content of labile phosphorus in water, acid-insoluble and alkali-soluble fractions. The content of fractions changed according to phosphorus concentration in the media and growth phase. During growth on all three media used, the cytochecmical behavior of polyphosphate changed considerably. The results obtained in this study reveal a potential of Cunninghamella elegans in the polyphosphate accumulation, and suggest a future application in the biotechnological processes.O crescimento, consumo de fosfato e glicose, bem como o conteúdo de fósforo, a distribuição, estrutura e localização de polifosfato foram avaliados no micélio de Cunninghamella elegans cultivado em meios contendo diferentes concentrações de fosfato. Os resultados permitiram verificar a influência dessas concentrações de fosfato sobre o crescimento do fungo estudado. A maior concentração de fosfato proporcionou maior rendimento da biomassa ao longo do crescimento. Uma relação entre consumo de fosfato e glicose do meio foi observada em relação ao crescimento e a quantidade de polifosfato total nos

  10. Cadmium Tolerance and Removal from Cunninghamella elegans Related to the Polyphosphate Metabolism

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    Hercília M. L. Rolim

    2013-03-01

    Full Text Available The aim of the present work was to study the cadmium effects on growth, ultrastructure and polyphosphate metabolism, as well as to evaluate the metal removal and accumulation by Cunninghamella elegans (IFM 46109 growing in culture medium. The presence of cadmium reduced growth, and a longer lag phase was observed. However, the phosphate uptake from the culture medium increased 15% when compared to the control. Moreover, C. elegans removed 70%–81% of the cadmium added to the culture medium during its growth. The C. elegans mycelia showed a removal efficiency of 280 mg/g at a cadmium concentration of 22.10 mg/L, and the removal velocity of cadmium was 0.107 mg/h. Additionally, it was observed that cadmium induced vacuolization, the presence of electron dense deposits in vacuoles, cytoplasm and cell membranes, as well as the distinct behavior of polyphosphate fractions. The results obtained with C. elegans suggest that precipitation, vacuolization and polyphosphate fractions were associated to cadmium tolerance, and this species demonstrated a higher potential for bioremediation of heavy metals.

  11. Microbial biotransformation of cryptotanshinone by Cunninghamella elegans and its application for metabolite identification in rat bile.

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    Sun, Jiang-Hao; Yang, Min; Ma, Xiao-Chi; Kang, Jie; Han, Jian; Guo, De-An

    2009-06-01

    Cryptotanshinone (1) is one of the major bioactive constituents in Salvia miltiorrhiza Bunge. Preparative-scale biotransformation of cryptotanshinone by Cunninghamella elegans (AS 3.2082) produced three new products, which were identified as (3R,15R)-3-hydroxycryptotanshinone (2), (3S,15R)-3-hydroxycryptotanshinone (3), and (4S,15R)-18-hydroxycryptotanshinone (4), respectively. The structural elucidation was based primarily on 1D and 2D NMR and HR-ESI-MS analyses. The absolute configuration of these three products was confirmed by comparison of their circular dichroism spectra with those of the known compounds. These biotransformed metabolites were used as for the comparison of in vivo metabolites in rat bile sample after intravenous administration and they are identical to three of the minor hydroxylated metabolites in vivo, which suggested that microbial biotransformation model was a useful and feasible approach for the preparation of mammalian metabolites in trace.

  12. Tributyltin (TBT) induces oxidative stress and modifies lipid profile in the filamentous fungus Cunninghamella elegans.

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    Bernat, Przemysław; Gajewska, Ewa; Szewczyk, Rafał; Słaba, Mirosława; Długoński, Jerzy

    2014-03-01

    To investigate the response of the tributyltin-degrading fungal strain Cunninghamella elegans to the organotin, a comparative lipidomics strategy was employed using an LC/MS-MS technique. A total of 49 lipid species were identified. Individual phospholipids were then quantified using a multiple reaction monitoring method. Tributyltin (TBT) caused a decline in the amounts of many molecular species of phosphatidylethanolamine or phosphatidylserine and an increase in the levels of phosphatidic acid, phosphatidylinositol and phosphatidylcholine. In the presence of TBT, it was observed that overall unsaturation was lower than in the control. Lipidome data were analyzed using principal component analysis, which confirmed the compositional changes in membrane lipids in response to TBT. Additionally, treatment of fungal biomass with butyltin led to a significant increase in lipid peroxidation. It is suggested that modification of the phospholipids profile and lipids peroxidation may reflect damage to mycelium caused by TBT.

  13. [Makeup of free intracellular amino acids in Cunninghamella elegans growing on media with hydrocarbons].

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    Kazanskaia, T B; Lieh Ts'ui Lin; Bekhtereva, M N

    1975-01-01

    The rate of growth of Cunninghamella elegans (--) 1204 is higher on a mineral medium with glucose (6.56 g/litre) than on a mineral medium containing undecane, tridecane, and pentadecane (0.72--0.87 g/litre); all glutamic acid is consumed only from the medium with glucose. The cells contain 15--16 free amino acids and 1--2 amides, glutamic and aspartic acids and alanine prevailing. The culture grown on the medium with glucose contains asparagine, and the cells cultivated on the medium with alkanes contain histidine. Non-proteinogenous aminobutyric acids were found in the pool of the cells grown on all tested media with an exception of the medium containing undecane.

  14. Green Conversion of Agroindustrial Wastes into Chitin and Chitosan by Rhizopus arrhizus and Cunninghamella elegans Strains

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    Berger, Lúcia Raquel Ramos; Stamford, Thayza Christina Montenegro; Stamford-Arnaud, Thatiana Montenegro; de Alcântara, Sergio Roberto Cabral; da Silva, Antonio Cardoso; da Silva, Adamares Marques; do Nascimento, Aline Elesbão; de Campos-Takaki, Galba Maria

    2014-01-01

    This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 103 and 4.68 × 103 g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria. PMID:24853288

  15. The fungus Cunninghamella elegans can produce human and equine metabolites of selective androgen receptor modulators (SARMs).

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    Rydevik, Axel; Thevis, Mario; Krug, Oliver; Bondesson, Ulf; Hedeland, Mikael

    2013-05-01

    1. Selective androgen receptor modulators (SARMs) are a group of substances that have potential to be used as doping agents in sports. Being a relatively new group not available on the open market means that no reference materials are commercially available for the main metabolites. In the presented study, the in vitro metabolism of SARMs by the fungus Cunninghamella elegans has been investigated with the purpose of finding out if it can produce relevant human and equine metabolites. 2. Three different SARMs, S1, S4 and S24, were incubated for 5 days with C. elegans. The samples were analysed both with and without sample pretreatment using ultra performance liquid chromatography coupled to high resolution mass spectrometry. 3. All the important phase I and some phase II metabolites from human and horse were formed by the fungus. They were formed through reactions such as hydroxylation, deacetylation, O-dephenylation, nitro-reduction, acetylation and sulfonation. 4. The study showed that the fungus produced relevant metabolites of the SARMs and thus can be used to mimic mammalian metabolism. Furthermore, it has the potential to be used for future production of reference material.

  16. Green Conversion of Agroindustrial Wastes into Chitin and Chitosan by Rhizopus arrhizus and Cunninghamella elegans Strains

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    Lúcia Raquel Ramos Berger

    2014-05-01

    Full Text Available This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses. The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC and the minimum bactericidal concentrations (MBC. The highest production of biomass (24.60 g/L, chitin (83.20 mg/g and chitosan (49.31 mg/g was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 103 and 4.68 × 103 g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria.

  17. Heavy metal biosorption by chitin and chitosan isolated from Cunninghamella elegans (IFM 46109 Remoção de metais pesados por quitina e quitosana isoladas de Cunninghamella elegans (IFM 46109

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    Luciana de Oliveira Franco

    2004-09-01

    Full Text Available Chitin and chitosan were extracted from mycelial biomass of Cunninghamella elegans and the performance for copper, lead and iron biosorption in aqueous solution was evaluated. The growth curve of C. elegans was accomplished by determination of biomass, pH, glucose and nitrogen consumption. Chitin and chitosan were extracted by alkali-acid treatment and the yields were 23.8 and 7.8%, respectively. For the adsorption analysis, the process of heavy uptake metal sorption was evaluated using polysaccharides solutions (1% w/v. The rate of metallic biosorption was dependent upon the concentration and pH of metal solutions, and the best results were observed with pH 4.0. Chitosan showed the highest affinity for copper and chitin for iron adsorption. The results suggest that C. elegans (IFM 46109 is an attractive source of production of chitin and chitosan, with a great potential of heavy metals bioremediation in polluted environments.Quitina e quitosana foram extraídas a partir da massa micelial de Cunninghamella elegans (IFM 46109 e avaliou-se a aplicação destes polissacarídeos na remoção dos metais pesados cobre, chumbo e ferro preparados em solução aquosa. O crescimento de C. elegans foi acompanhado através da determinação de biomassa, pH, consumo de glicose e de nitrogênio. A extração de quitina e quitosana realizou-se através de tratamento álcali-ácido e a produção dos polissacarídeos foi de 23,8 e 7,8 %, respectivamente. A avaliação do processo de remoção dos metais pesados foi realizada utilizando-se os polissacarídeos em solução a 1% (p/v. Os níveis de biossorção de metais foram dependentes da concentração e do pH das soluções. Os melhores resultados foram obtidos em pH 4,0. A quitosana mostrou maior índice de biossorção para o íon cobre e a quitina para o ferro. Os resultados sugerem que C.elegans pode ser considerada uma fonte atrativa para a produção alternativa de quitina e quitosana, e que demonstra

  18. Action of tributyltin (TBT) on the lipid content and potassium retention in the organotins degradating fungus Cunninghamella elegans.

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    Bernat, Przemysław; Słaba, Mirosława; Długoński, Jerzy

    2009-09-01

    The purpose of the presented paper was to study the effect of high concentrations of tributyltin (TBT) on the potassium retention and fatty acid (FA) composition of the fungus Cunninghamella elegans recognized as a very efficient TBT degrader. An increase in TBT had a strong influence on the potassium concentration in the fungus. In growth medium without TBT, the potassium content of the fungal cells was 5.8 mg K(+) g dry weight(-1). The maximum concentration of K(+) was 15.06 mg g(-1) dry weight at 30 mg l(-1) of TBT. The major FAs that characterized the tested strain were C16:0, C18:1, C18:2, C18:3 and C18:0. TBT in the concentration range 5-30 mg l(-1) strongly influenced the FA composition. In the presence of the organotin, the degree of saturation increased. It suggests that the observed changes promote an increase in the lipid ordering of the membrane by reducing its permeability and inhibiting potassium ion efflux.

  19. Effect of Corn Steep Liquor (CSL and Cassava Wastewater (CW on Chitin and Chitosan Production by Cunninghamella elegans and Their Physicochemical Characteristics and Cytotoxicity

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    Lúcia Raquel Ramos Berger

    2014-02-01

    Full Text Available Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL and cassava wastewater (CW established using a 22 full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L was obtained in trial 3 (5% CW, 8% CSL, the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL. Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 103 Da. Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan.

  20. Organic matter inoculated with diazotrophic bacterium Beijerinckia indica and Cunninghamella elegans fungus containing chitosan on banana “Williams” in field

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    Newton Pereira Stamford

    2017-01-01

    Full Text Available The production of biofertilizers from rocks increases nutrients for plant nutrition without environmental pollution. The aim of this study was to evaluate the effectiveness of biofertilizers from phosphate and potassium rocks mixed with organic matter (earthworm compound inoculated with free living diazotrophic bacteria (NFB 10001 and Cunninghamella elegans (fungus with chitosan on yield, characteristics, and nutrient uptake of banana (cv. Williams, and attributes of a Red Yellow Argisoil of the rainforest Zone of Pernambuco, Brazil. The experimental design included two biofertilizers: (a PK rock biofertilizers plus organic matter (NPKB and (b bioprotector (NPKP applied at 50, 100 and 150% of the recommended rate for banana, which were compared with soluble mineral fertilizers (NPKF applied at the recommended rate, and earthworm compound (20 ton ha-1. The best results of the plant parameters were obtained with NPKB and NPKP applied at the highest rates (150% RR. A normal yield was produced when NPKB and NPKP were applied at the highest rates and NPKF at the recommended rate. The available P and K in the soil showed a significant fertilization effect, especially when NPKB and NPKP were applied at the highest rates. The biofertilizer and bioprotector may be alternatives to mineral soluble fertilizers.

  1. Carbazole hydroxylation by the filamentous fungi of the Cunninghamella species.

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    Zawadzka, K; Bernat, P; Felczak, A; Lisowska, K

    2015-12-01

    Nitrogen heterocyclic compounds, especially carbazole, quinolone, and pyridine are common types of environmental pollutants. Carbazole has a toxic influence on living organisms, and the knowledge of its persistence and bioconversion in ecosystems is still not complete. There is an increasing interest in detoxification of hazardous xenobiotics by microorganisms. In this study, the ability of three filamentous fungi of the Cunninghamella species to eliminate carbazole was evaluated. The Cunninghamella elegans IM 1785/21Gp and Cunninghamella echinulata IM 2611 strains efficiently removed carbazole. The IM 1785/21Gp and IM 2611 strains converted 93 and 82 % of the initial concentration of the xenobiotic (200 mg L(-1)) after 120 h incubation. 2-Hydroxycarbazole was for the first time identified as a carbazole metabolite formed by the filamentous fungi of the Cunninghamella species. There was no increase in the toxicity of the postculture extracts toward Artemia franciscana. Moreover, we showed an influence of carbazole on the phospholipid composition of the cells of the tested filamentous fungi, which indicated its harmful effect on the fungal cell membrane. The most significant modification of phospholipid levels after the cultivation of filamentous fungi with the addition of carbazole was showed for IM 1785/21Gp strain.

  2. Biotransformation of indomethacin by the fungus Cunninghamella blakesleeana

    Institute of Scientific and Technical Information of China (English)

    Peng ZHANG; Li-hong LIN; Hai-hua HUANG; Hai-yan XU; Da-fang ZHONG

    2006-01-01

    Aim: To investigate the biotransformation of indomethacin, the first of the newer nonsteroidal anti-inflammatory drugs, by filamentous fungus and to compare the similarities between microbial transformation and mammalian metabolism of indomethacin. Methods: Five strains of Cunninghamella (C elegans AS 3.156, C elegans AS 3.2028, C blakesleeana AS 3.153, C blakesleeana AS 3.910 and C echinulata AS 3.2004) were screened for their ability to catalyze the biotransformation of indomethacin. Indomethacin was partially metabolized by five strains of Cunninghamella, and C blakesleeana AS 3.910 was selected for further investigation. Three metabolites produced by C blakesleeana AS 3.910 were isolated using semi-preparative HPLC, and their structures were identified by a combination analysis of LC/MSn and NMR spectra. These three metabolites were separated and quantitatively assayed by liquid chromatography-ion trap mass spectrometry. Results: After 120 h of incubation with C blakesleeana AS 3.910, approximately 87.4% of indomethacin was metabolized to three metabolites: O-desmethylindomethacin (DMI, M1, 67.2%), Af-deschlorobenzoylindomethacin (DBI, M2,13.3%) and O-desmethyl-AT-deschlorobenzoylindomethacin (DMBI, M3, 6.9%). Three phase I metabolites of indomethacin produced by C blakesleeana AS 3.910 were identical to those obtained in humans. Conclusion: C blakesleeana could be a useful tool for generating the mammalian phase I metabolites of indomethacin.

  3. Biotransformation of metoprolol by the fungus Cunninghamella blakes-leeana

    Institute of Scientific and Technical Information of China (English)

    Bin MA; Hai-hua HUANG; Xiao-yan CHEN; Yu-ming SUN; Li-hong LIN; Da-fang ZHONG

    2007-01-01

    Aim: To investigate the biotransformation of metoprolol, a β1-cardioselective adrenoceptor antagonist, by filamentous fungus, and to compare the parallels between microbial transformation and mammalian metabolism. Methods: Five strains of Cunninghamella (C elegans AS 3.156, C elegans AS 3.2028, C echinulata AS 3.2004, C blakesleeana AS 3.153 and AS 3.910) were screened for the ability to transform metoprolol. The metabolites of metoprolol produced by C blakesleeana AS 3.153 were separated and assayed by liquid chromatography-tandem mass spectrometry (LC/MSn). The major metabolites were isolated by semipreparative HPLC and the structures were identified by a combination of LC/MSn and nuclear magnetic resonance analysis. Results: Metoprolol was transformed to 7 metabolites; 2 were identified as new metabolites and 5 were known metabolites in mammals. Conclusion: The microbial transformation of metoprolol was similar to the metabolism in mammals. The fungi belonging to Cunninghamella species could be used as complementary models for predicting in vivo metabolism and producing quantities of metabolite references for drugs like metoprolol.

  4. Propranolol metabolism by Cunninghamella bainieri.

    Science.gov (United States)

    Foster, B C; Buttar, H S; Qureshi, S A; McGilveray, I J

    1989-05-01

    1. Incubations of racemic propranolol alone or in the presence of either quinidine or sparteine were performed with Cunninghamella bainieri. 2. Five mammalian metabolites of propranolol (4-hydroxypropranolol, desisopropyl-propranolol, 1-naphthoxylactic acid, propranolol glycol and 1-naphthoxyacetic acid) were present in unhydrolysed extracts of the incubation medium according to h.p.l.c. and g.l.c. analyses. The relative proportion of 4-hydroxypropranolol increased after enzymic treatment. 3. Propranolol not only had a fungistatic effect, but also caused morphological changes in the organism, which were accompanied by decomposition of 4-hydroxypropranolol and formation of a greenish-brown colour in the incubation medium. 4. Drug interaction experiments yielded results which paralleled those reported in mammals. 5. The findings indicate that C. bainieri may be a useful microbial model for drug disposition and interaction studies.

  5. DNA barcoding of clinically relevant Cunninghamella species

    NARCIS (Netherlands)

    Yu, Jin; Walther, G; Van Diepeningen, A D; Gerrits Van Den Ende, A H G; Li, Ruo-Yu; Moussa, T A A; Almaghrabi, O A; De Hoog, G S

    2015-01-01

    Mucormycosis caused, in part, by representatives of the genus Cunninghamella is a severe infection with high mortality in patients with impaired immunity. Several species have been described in the literature as etiologic agents. A DNA barcoding study using ITS rDNA and tef-1α provided concordance o

  6. Cunninghamella echinulata causing fatally invasive fungal sinusitis.

    Science.gov (United States)

    LeBlanc, Robert E; Meriden, Zina; Sutton, Deanna A; Thompson, Elizabeth H; Neofytos, Dionissios; Zhang, Sean X

    2013-08-01

    We report a fatal case of invasive fungal sinusitis caused by Cunninghamella echinulata in a febrile, neutropenic 15-year-old male with relapsing acute leukemia. The isolate was recovered from a nasal biopsy from the right middle meatus, and microscopic examination of the tissue revealed angioinvasion and necrosis. Human infection caused by this organism has not been well documented; however, this report alerts us to its life-threatening potential.

  7. Biotransformation of protriptyline by filamentous fungi and yeasts.

    Science.gov (United States)

    Duhart, B T; Zhang, D; Deck, J; Freeman, J P; Cerniglia, C E

    1999-07-01

    1. The potential of various fungi to metabolize protriptyline (an extensively used antidepressant) was studied to investigate similarities between mammalian and microbial metabolism. 2. Metabolites produced by each organism were isolated by high-pressure liquid chromatography and identified by nuclear magnetic resonance and mass spectrometry. The metabolites identified in one or more fungi were 2-hydroxyprotriptyline, N-desmethylprotriptyline, N-acetylprotriptyline, N-acetoxyprotriptyline, 14-oxo-N-desmethylprotriptyline, 2-hydroxy-acetoxyprotriptyline and 3-(5-hydrodibenzo[bf][7]annulen-5-yl)propanoic acid. 3. Among 27 filamentous fungi and yeast species screened, Fusarium oxysporum f. sp. pini 2380 metabolized 97% of the protriptyline added. Several other fungi screened gave significant metabolism of protriptyline, including Cunninghamella echinulata ATCC 42616 (67%), C. elegans ATCC 9245 (17%), C. elegans ATCC 36112 (22%), C. phaeospora ATCC 22110 (50%), F. moniliforme MRC-826 (33%) and F. solani 3179 (12%). 4. F. oxysporum f. sp. pini produced phase I and phase II metabolites and thus is a suitable microbial model for protriptyline metabolism.

  8. Microbial transformation of oxandrolone with Macrophomina phaseolina and Cunninghamella blakesleeana.

    Science.gov (United States)

    Smith, Colin; Wahab, Atia-Tul-; Khan, Mahwish Shafi Ahmed; Ahmad, Malik Shoaib; Farran, Dina; Iqbal Choudhary, M; Baydoun, Elias

    2015-10-01

    Microbial transformation of oxandrolone (1) was carried out by using Cunninghamella blakesleeana and Macrophomina phaseolina. Biotransformation of 1 with M. phaseolina yielded four new metabolites, 11β,17β-dihydroxy-17α-(hydroxymethyl)-2-oxa-5α-androstan-3-one (2), 5α,11β,17β-trihydroxy-17α-methyl-2-oxa-androstan-3-one (3), 17β-hydroxy-17α-methyl-2-oxa-5α-androstan-3,11-dione (4), and 11β,17β-dihydroxy-17α-methyl-2-oxa-5α-androstan-3-one (5). Whereas a new metabolite, 12β,17β-dihydroxy-17α-methyl-2-oxa-5α-androstan-3-one (6), was obtained through the microbial transformation of oxandrolone (1) with C. blakesleeana. The structures of isolated metabolites were characterized on the basis of MS and NMR spectroscopic data. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Biotransformation of Meloxicam by Cunninghamella blakesleeana: Significance of Carbon and Nitrogen Source

    OpenAIRE

    Shyam Prasad, Gurram; Narasimha Rao, Kollu; Preethi, Rama; Girisham, Sivasri; S. M. Reddy

    2011-01-01

    Influence of carbon and nitrogen source, on biotransformation of meloxicam was studied by employing Cunninghamella blakesleeana NCIM 687 with an aim to achieve maximum transformation of meloxicam and in search of new metabolites. The transformation was confirmed by HPLC and based on LC–MS–MS data and previous reports the metabolites were predicted as 5-hydroxymethyl meloxicam, 5-carboxy meloxicam and a novel metabolite. The quantification of metabolites was performed using HPLC peak areas. Th...

  10. Bioremediation of PCP by Trichoderma and Cunninghamella Strains Isolated from Sawdust

    Directory of Open Access Journals (Sweden)

    Ngieng Ngui Sing

    2014-12-01

    Full Text Available Four fungal isolates, SD12, SD14, SD19 and SD20 isolated from the aged sawdust grew on agar plates supplemented with PCP up to a concentration of 100 mg L-1. At high PCP concentration, isolate SD12 showed the highest radial growth rate of 10 mm day-1, followed by SD14 and SD19 both with 4.5 mm day-1 and SD20 with 4.2 mm day-1. Ultrastructural study on the effect of PCP on the PCP tolerant fungi using scanning electron microscope showed that high concentration of PCP caused the collapse of both fungal hyphae and spores. Among the four PCP tolerant fungi examined, isolate SD12 showed the least structural damage at high PCP concentration of 100 mg L-1. This fungal isolate was further characterized and identified as Cunninghamella sp. UMAS SD12. Preliminary PCP biodegradation trial performed in liquid minimal medium supplemented with 20 mg L-1 of PCP using Cunninghamella sp. UMAS SD12 showed that the degradation up to 51.7% of PCP in 15 days under static growth condition.

  11. Pulmonary mucormycosis (Cunninghamella bertholletiae) with cavitation diagnosed using ultra-thin fibre-optic bronchoscopy.

    Science.gov (United States)

    Yagi, Shin-Ichi; Miyashita, Naoyuki; Fukuda, Minoru; Obase, Yasushi; Yoshida, Koichiro; Miyauchi, Ayaka; Kawasaki, Kouzou; Soda, Hiroshi; Oka, Mikio

    2008-03-01

    Recently, ultra-thin bronchoscopy has made it possible to observe smaller bronchi not visualized using standard techniques. We describe a case of pulmonary mucormycosis with cavitation, diagnosed using an ultra-thin bronchoscope. A 15-year-old girl with acute myeloid leukaemia had taken oral prednisolone, 60 mg/day, for graft versus host disease after haematopoietic stem cell transplantation. She was admitted to our hospital with fever and a large cavitary lesion in the right hilum. Using an ultra-thin bronchoscope, the interior of the cavity in the superior segment of the right lower lobe was observed. The bronchoscopic findings revealed debris adhering to the cavity wall with a small volume of effusion. Cunninghamella bertholletiae was isolated from the effusion specimen obtained using the bronchoscope. Pulmonary mucormycosis (C. bertholletiae) complicating an immunocompromised state was diagnosed. Ultra-thin bronchoscopy is useful to diagnose complex pulmonary infections and more research is needed to verify its clinical indications and utility.

  12. Cunninghamella bertholletiae exhibits increased resistance to human neutrophils with or without antifungal agents as compared to Rhizopus spp.

    Science.gov (United States)

    Simitsopoulou, Maria; Georgiadou, Elpiniki; Walsh, Thomas J; Roilides, Emmanuel

    2010-08-01

    Among Zygomycetes, Cunninghamella bertholletiae occurs less frequently as the etiologic agent of human disease but causes more aggressive, refractory, and fatal infections despite antifungal therapy. Little is known about the differential innate host response against Cunninghamella and other Zygomycetes in the presence of antifungal agents. We therefore studied the activity of human neutrophils (PMNs) alone or in combination with caspofungin, posaconazole (PSC), and voriconazole (VRC) against hyphae of Rhizopus oryzae, Rhizopus microsporus and C. bertholletiae. Hyphal damage was measured by XTT metabolic assay and release of IL-6, IL-8 and TNF-alpha from PMNs by ELISA. Cunninghamella bertholletiae was more resistant to PMN-induced hyphal damage than either Rhizopus spp. at effector:target (E:T) ratios of 1:1, 5:1 and 10:1 (P Rhizopus spp. (P < 0.01). No IL-6 was released from PMNs exposed to the three Zygomycetes. In comparison to R. oryzae and R. microsporus, C. bertholletiae is more resistant to PMN-induced hyphal damage with or without antifungal therapy and is more capable of suppressing release of IL-8.

  13. Effect of nitrogen sources on the activities of lipogenic enzymes in oleaginous fungus Cunninghamella echinulata.

    Science.gov (United States)

    Certik, Milan; Megova, Jana; Horenitzky, Robert

    1999-12-01

    Various inorganic and organic nitrogen sources were used to compare their effects on the lipogenesis and the activities of lipogenic enzymes (providing acetyl-CoA and donating NADPH) in gamma-linolenic acid-producing fungus Cunninghamella echinulata. Lipid accumulation was enhanced by organic nitrogen, among them the presence of corn-steep led to almost 40% oil in the biomass. While organic nitrogen increased activities of acetyl-CoA carboxylase (ACC) and malic enzyme (ME), ATP:citrate lyase (ACL) was rapidly enhanced by ammonium ion. The use of NaNO(3) resulted in high activities of glucose 6-phosphate dehydrogenase (GPD) and 6-phosphogluconate dehydrogenase (PGD). NADP-isocitrate dehydrogenase (NADP-ICD) was more active when the fungus utilized all inorganic N-compounds. The rise of nitrogen concentration in medium was accompanied with reduced lipid accumulation and a fall of ACL, ACC, and ME. In contrast, N-sufficient conditions favored biomass growth and elevated activities of GPD and PGD. Kinetic experiments also suggest that a significant portion of the required acetyl-CoA was being provided via ACL and ACC, and ME (probably coupled with GPD) channeled the NADPH into the fatty acid biosynthesis. The contribution of the lipogenic enzymes to metabolic pathways other than lipogenesis is also discussed.

  14. Biotransformation of androgenic steroid mesterolone with Cunninghamella blakesleeana and Macrophomina phaseolina.

    Science.gov (United States)

    Ahmad, Malik Shoaib; Zafar, Salman; Bibi, Marium; Bano, Saira; Atia-Tul-Wahab; Atta-Ur-Rahman; Iqbal Choudhary, M

    2014-04-01

    Fermentation of mesterolone (1) with Cunninghamella blakesleeana yielded four new metabolites, 1α-methyl-1β,11β,17β-trihydroxy-5α-androstan-3-one (2), 1α-methyl-7α,11β,17β-trihydroxy-5α-androstan-3-one (3), 1α-methyl-1β,6α,17β-trihydroxy-5α-androstan-3-one (4) and 1α-methyl-1β,11α,17β-trihydroxy-5α-androstan-3-one (5), along with three known metabolites, 1α-methyl-11α,17β-dihydroxy-5α-androstan-3-one (6), 1α-methyl-6α,17β-dihydroxy-5α-androstan-3-one (7) and 1α-methyl-7α,17β-dihydroxy-5α-androstan-3-one (8). Biotransformation of 1 with Macrophomina phaseolina also yielded a new metabolite, 1α-methyl, 17β-hydroxy-5α-androstan-3,6-dione (9). The isolated metabolites were subjected to various in vitro biological assays, such as anti-cancer, inhibition of α-glucosidase, and phosphodiesterase-5 enzymes and oxidative brust. However, no significant results were observed. This is the first report of biotransformation of 1 with C. blakesleeana and M. phaseolina. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Disseminated Cunninghamella bertholletiae infection with spinal epidural abscess in a kidney transplant patient: case report and literature review.

    Science.gov (United States)

    Navanukroh, O; Jitmuang, A; Chayakulkeeree, M; Ngamskulrungroj, P

    2014-08-01

    Cunninghamella bertholletiae is a rare cause of invasive mucormycosis. We report the case of a 42-year-old Thai woman who suffered from disseminated C. bertholletiae infection. The patient developed dry cough, sharp shooting pain in the left buttock referred to the left leg, and fever 1 month after undergoing deceased-donor kidney transplantation. Radiographic studies exhibited multiple pulmonary cavities, osteomyelitis of the sacral spine, epidural abscess along the lumbrosacral spine, and paravertebral soft tissue involvement. Surgical debridement of the epidural abscess concurrent with prolonged intravenous administration of amphotericin B resulted in a good outcome.

  16. Rapid Extracellular Biosynthesis of Silver Nanoparticles by Cunninghamella phaeospora Culture Supernatant

    Science.gov (United States)

    Ghareib, Mohamed; Tahon, Medhat Abu; Saif, Mona Mostafa; El-Sayed Abdallah, Wafaa

    2016-01-01

    The development of green approaches for the biosynthesis of silver nanoparticles (AgNPs) is of prime significance in the field of nanotechnology research. A fast and eco-friendly protocol for the biosynthesis of extracellular AgNPs using culture supernatant (CS) from the fungus Cunninghamella phaeospora was studied in this work. This CS was proved as a potential new source for the extracellular biosynthesis of AgNPs. The AgNPs were formed at 100 oC and pH 9 within four min of contact between CS and 1mM silver nitrate (AgNO3) solution. Nitrate reductase (NR) was confirmed to play a pivotal role in the biosynthesis of AgNPs. The enzyme expressed its highest activity at 80 oC and pH 9. At 100 oC the enzyme retained 70% of its original activity for one hour. The half-life (T1/2) of the enzyme activity was calculated to be 1.55 h confirming its thermostability. The produced AgNPs were characterized by UV-Vis spectroscopy, high resolution-transmission electron microscope (HR-TEM) and x-ray diffraction (XRD). These NPs showed an absorption peak at 415 nm in UV-Vis spectrum corresponding to the plasmon resonance of AgNPs. Transmission electron micrographs revealed the production of monodispersed spherical NPs with average particle size 14 nm. XRD spectrum of the NPs confirmed the formation of metallic crystalline silver. It was also suggested that the aromatic amino acids play a role in the biosynthesis process. The current research provided an insight on the green biosynthesis of AgNPs including some mechanistic aspects using a new mycogenic source.

  17. Medium Optimization for the Production of Lipidless Biomass By Cunninghamella sp. 2A1 Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Siti Aminah, S.

    2006-01-01

    Full Text Available A statistical design approach has been used to optimize the production of biomass by Cunninghamella sp. 2A1, evaluated based on lipidless biomass. A 2^3 full factorial central composite design (CCD was chosen to study the combined effects of three factors; ammonium tartrate, peptone and glucose concentrations. The p-value for each factor was <0.05 suggesting that these factors have significant effects on the production of lipidless biomass. The production is represented by a linear model with p-value <0.0001. The optimized medium consisting of 3.86g/L ammonium tartrate, 55.84g/L glucose and 7.73g/L peptone predicted a lipidless biomass of 16.83g/L. Results from four replications based on the optimized medium produced an average of 18.48g/L lipidless biomass, which is in close agreement with the predicted value. The coefficient for glucose was the highest indicating it to be the most significant factor affecting lipidless biomass production.

  18. Optimization of aeration and agitation rate for lipid and gamma linolenic acid production by Cunninghamella bainieri 2A1 in submerged fermentation using response surface methodology.

    Science.gov (United States)

    Saad, Normah; Abdeshahian, Peyman; Kalil, Mohd Sahaid; Yusoff, Wan Mohtar Wan; Hamid, Aidil Abdul

    2014-01-01

    The locally isolated filamentous fungus Cunninghamella bainieri 2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA). The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production. Process analysis showed that linear and quadratic effect of agitation intensity significantly influenced lipid production process (P production (P production of lipid in the bioreactor.

  19. Comparison of Methods for Isolating High Quality DNA and RNA from an Oleaginous Fungus Cunninghamella bainieri Strain 2a1

    Directory of Open Access Journals (Sweden)

    Noor Adila, A. K.

    2007-01-01

    Full Text Available A number of protocols have been reported for efficient fungal DNA and RNA isolation. However, many of these methods are often designed for certain groups or morphological forms of fungi and, in some cases, are species dependent. In this report, we compared four published protocols for DNA isolation from a locally isolated oleaginous fungus, Cunninghamella bainieri strain 2a1. These protocols either involved the use of polyvinyl pyrrolidone (PVP, hexacetyltrimethylammonium bromide (CTAB or without using PVB or CTAB. For RNA isolation, we tested two published protocols, one of which is based on TRI REAGENT (Molecular Research Center, USA and another is simple method employing phenol for RNA extraction and LiCl for precipitation. We found that the protocol involving the use of CTAB produced the highest genomic DNA yield with the best quality compared to other protocols. In the presence of CTAB, unwanted polysaccharides were removed and this method yielded an average amount of 816 ± 12.2 µg DNA/g mycelia with UV absorbance ratios A260/280 and A260/230 of 1.67 ± 0.64 and 1.97 ± 0.23, respectively. The genomic DNA isolated via this protocol is also suitable for PCR amplification and restriction enzyme digestion. As for RNA isolation, the method involving phenol extraction and LiCl precipitation produced the highest yield of RNA with an average amount of 372 ± 6.0 µg RNA/g mycelia. The RNA appears to be relatively pure since it has UV absorbance ratios A260/280 and A260/230 of 1.89 ± 2.00 and 1.99 ± 0.03, respectively. Finally, we have demonstrated that this method could produce RNA of sufficient quality for RT-PCR that amplified a 600 bp fragment of ∆12-fatty acid desaturase gene in C. bainieri.

  20. Biosurfactant-and-Bioemulsifier Produced by a Promising Cunninghamella echinulata Isolated from Caatinga Soil in the Northeast of Brazil

    Directory of Open Access Journals (Sweden)

    Nadielly R. Andrade Silva

    2014-09-01

    Full Text Available A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW and corn steep liquor (CSL as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E24 of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w, carbohydrates (35.2% w/w and protein (20.3% w/w. In addition, the biosurfactant solution (1% demonstrated its ability for an oil displacement area (ODA of 37.36 cm2, which is quite similar to that for Triton X-100 (38.46 cm2. The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v. The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.

  1. Biosurfactant-and-bioemulsifier produced by a promising Cunninghamella echinulata isolated from Caatinga soil in the northeast of Brazil.

    Science.gov (United States)

    Andrade Silva, Nadielly R; Luna, Marcos A C; Santiago, André L C M A; Franco, Luciana O; Silva, Grayce K B; de Souza, Patrícia M; Okada, Kaoru; Albuquerque, Clarissa D C; da Silva, Carlos A Alves; Campos-Takaki, Galba M

    2014-09-01

    A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E₂₄) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm², which is quite similar to that for Triton X-100 (38.46 cm²). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%-6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.

  2. Globins in Caenorhabditis elegans.

    Science.gov (United States)

    Tilleman, Lesley; Germani, Francesca; De Henau, Sasha; Geuens, Eva; Hoogewijs, David; Braeckman, Bart P; Vanfleteren, Jacques R; Moens, Luc; Dewilde, Sylvia

    2011-03-01

    Extensive in silico search of the genome of Caenorhabditis elegans revealed the presence of 33 genes coding for globins that are all transcribed. These globins are very diverse in gene and protein structure and are localized in a variety of cells, mostly neurons. The large number of C. elegans globin genes is assumed to be the result of multiple evolutionary duplication and radiation events. Processes of subfunctionalization and diversification probably led to their cell-specific expression patterns and fixation into the genome. To date, four globins (GLB-1, GLB-5, GLB-6, and GLB-26) have been partially characterized physicochemically, and the crystallographic structure of two of them (GLB-1 and GLB-6) was solved. In this article, a three-dimensional model was designed for the other two globins (GLB-5 and GLB-26), and overlays of the globins were constructed to highlight the structural diversity among them. It is clear that although they all share the globin fold, small variations in the three-dimensional structure have major implications on their ligand-binding properties and possibly their function. We also review here all the information available so far on the globin family of C. elegans and suggest potential functions. Copyright © 2011 Wiley Periodicals, Inc.

  3. C. elegans in Complex Media

    CERN Document Server

    Shen, X N; Arratia, P E

    2011-01-01

    We experimentally studied the locomotion of the nematode C. elegans in both fluidic and granular media. In this fluid dynamics video, we show the motility gaits of the nematode in these two environments. The motility of the nematode C. elegans is investigated using particle tracking methods. Experimental results show that different transport patterns emerge from the fluidic and granular media during the nematode locomotion.

  4. 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

  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. Intermediate Filaments in Caenorhabditis elegans.

    Science.gov (United States)

    Zuela, Noam; Gruenbaum, Yosef

    2016-01-01

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

  7. Toxicity testing using Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  8. Gustatory Behaviour in Caenorhabditis elegans

    NARCIS (Netherlands)

    R.K. Hukema (Renate)

    2006-01-01

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

  9. Gustatory Behaviour in Caenorhabditis elegans

    NARCIS (Netherlands)

    R.K. Hukema (Renate)

    2006-01-01

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

  10. Biolistic transformation of Caenorhabditis elegans

    NARCIS (Netherlands)

    Isik, M.; Berezikov, E.

    2013-01-01

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

  11. Metabolic inhibition of meloxicam by specific CYP2C9 inhibitors in Cunninghamella blakesleeana NCIM 687: in silico and in vitro studies.

    Science.gov (United States)

    Prasad, G Shyam; Srisailam, K; Sashidhar, R B

    2016-01-01

    Specific inhibitors of Cytochrome P4502C9 enzyme (CYP2C9) viz. clopidogrel, fenofibrate fluvoxamine and sertraline at concentration of 50, 100, 150 and 200 µM were employed to investigate the nature of enzyme involved in bioconversion of meloxicam to its main metabolite 5-OH methyl meloxicam by Cunninghamella blakesleeana. Virtual screening for interaction of specific CYP2C9 inhibitors with human CYP2C9 enzyme was performed by molecular docking using Auto dock vina 4.2 version. The in silico studies were further substantiated by in vitro studies, which indicated fenofibrate to be a potent inhibitor of CYP2C9 enzyme followed by sertraline, clopidogrel and fluvoxamine, respectively. Two-stage fermentation protocol was followed to study metabolism of meloxicam and its inhibition by different CYP2C9 inhibitors. Meloxicam metabolites were identified using HPLC, LC-MS analysis and based on previous reports, as 5-OH methyl meloxicam (M1), 5-carboxy meloxicam (M2) and an unidentified metabolite (M3). All the inhibitors tested in the study showed a clear concentration dependent inhibition of meloxicam metabolism. The results suggest that the enzymes involved in metabolism of meloxicam in C. blakesleeana are akin to mammalian metabolism. Hence, C. blakesleeana can be used as a model organism in studying drug interactions and also in predicting mammalian drug metabolism.

  12. Optimization of Aeration and Agitation Rate for Lipid and Gamma Linolenic Acid Production by Cunninghamella bainieri 2A1 in Submerged Fermentation Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Normah Saad

    2014-01-01

    Full Text Available The locally isolated filamentous fungus Cunninghamella bainieri 2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA. The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production. Process analysis showed that linear and quadratic effect of agitation intensity significantly influenced lipid production process (P<0.01. The quadratic model also indicated that the interaction between aeration rate and agitation speed had a highly significant effect on lipid production (P<0.01. Experimental results showed that a lipid content of 38.71% was produced in optimum conditions using an airflow rate and agitation speed of 0.32 vvm and 599 rpm, respectively. Similar results revealed that 0.058 (g/g gamma-linolenic acid was produced in optimum conditions where 1.0 vvm aeration rate and 441.45 rpm agitation rate were used. The regression model confirmed that aeration and agitation were of prime importance for optimum production of lipid in the bioreactor.

  13. The Nucleolus of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Li-Wei Lee

    2012-01-01

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

  14. Ascaroside signaling in C. elegans*

    OpenAIRE

    Ludewig, Andreas H; Schroeder, Frank C.

    2013-01-01

    Over the past 10 years, the relevance of small-molecule signaling for many aspects of C. elegans development and behavior has become apparent. One prominent group of small-molecule signals are the ascarosides, which control dauer entry and exit as well as a variety of sex-specific and social behaviors, including male attraction, hermaphrodite repulsion, olfactory plasticity, and aggregation. This wide range of biological functions is facilitated by a great diversity of ascaroside chemical str...

  15. Sensory Transduction in Caenorhabditis elegans

    Science.gov (United States)

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

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

  16. Antimicrobial peptides in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    A Bogaerts

    2010-01-01

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

  17. Biotransformation of anabolic compound methasterone with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini, and TNF-α inhibitory effect of transformed products.

    Science.gov (United States)

    Ahmad, Malik Shoaib; SammerYousuf; Atia-Tul-Wahab; Jabeen, Almas; Atta-Ur-Rahman; Choudhary, M Iqbal

    2017-04-09

    Microbial transformation of methasterone (1) was investigated with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini. Biotransformation of 1 with M. phaseolina yielded metabolite 2, while metabolites 3-7 were obtained from the incubation of 1 with C. blakesleeana. Metabolites 8-13 were obtained through biotransformation with F. lini. All metabolites, except 13, were found to be new. Methasterone (1) and its metabolites 2-6, 9, 10, and 13 were then evaluated for their immunomodulatory effects against TNF-α, NO , and ROS production. Among all tested compounds, metabolite 6 showed a potent inhibition of proinflammatory cytokine TNF-α (IC50 = 8.1 ± 0.9 µg/mL), as compared to pentoxifylline used as a standard (IC50 = 94.8± 2.1 µg/mL). All metabolites were also evaluated for the inhibition of NO production at concentration of 25 µg/mL. Metabolites 6 (86.7 ± 2.3%) and 13 (62.5 ± 1.5%) were found to be the most potent inhibitors of NO as compared to the standard N(G)-monomethyl-L-arginine acetate (65.6 ± 1.1%). All metabolites were found to be non-toxic against PC3, HeLa, and 3T3 cell lines. Observed inhibitory potential of metabolites 6 and 13 against pro-inflammatory cytokine TNF-α, as well as NO production makes them interesting leads for further studies. Copyright © 2017. Published by Elsevier Inc.

  18. 小克银汉霉属微生物模型在体外药物代谢研究中的应用%Application of Cunninghamella Matruchot microbial transformation model in drug metabolization in vitro

    Institute of Scientific and Technical Information of China (English)

    任丽艳; 关瑾; 陈星; 王慧泽

    2011-01-01

    药物代谢在药效和安全性评价中是非常重要的,而利用微生物转化为药物体外代谢模型则具有很多优势.小克银汉霉属的许多菌株具有与人体类似的Ⅰ相和Ⅱ相药物代谢酶,其微生物模型能对多种底物进行高效转化.本文对其在药物代谢方面的应用进行综述,并对其未来的发展进行了展望.%Drug metabolism constitutes an important step in the evaluation of drug efficacy and safety. Hiere are many advantages to using microbial transformation model in medicine metabolization in vitro. Many strains of cunning-hamella matruchot have a similar phase I and II enzymes to the human body. The Cunninghamella Matruchot fungus can carry out highly-efficient transformation on many compounds. In this paper, application of Cunningkammella matnichor fungus in vitro microbial models is reviewed and future development in the metabolism field is predicted.

  19. Ritmos circadianos en Caenorhabditis elegans

    OpenAIRE

    Migliori, María Laura

    2012-01-01

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

  20. Using C. elegans for antimicrobial drug discovery

    Science.gov (United States)

    Desalermos, Athanasios; Muhammed, Maged; Glavis-Bloom, Justin; Mylonakis, Eleftherios

    2011-01-01

    Introduction The number of microorganism strains with resistance to known antimicrobials is increasing. Therefore, there is a high demand for new, non-toxic and efficient antimicrobial agents. Research with the microscopic nematode Caenorhabditis elegans can address this high demand for the discovery of new antimicrobial compounds. In particular, C. elegans can be used as a model host for in vivo drug discovery through high-throughput screens of chemical libraries. Areas covered This review introduces the use of substitute model hosts and especially C. elegans in the study of microbial pathogenesis. The authors also highlight recently published literature on the role of C. elegans in drug discovery and outline its use as a promising host with unique advantages in the discovery of new antimicrobial drugs. Expert opinion C. elegans can be used, as a model host, to research many diseases, including fungal infections and Alzheimer’s disease. In addition, high-throughput techniques, for screening chemical libraries, can also be facilitated. Nevertheless, C. elegans and mammals have significant differences that both limit the use of the nematode in research and the degree by which results can be interpreted. That being said, the use of C. elegans in drug discovery still holds promise and the field continues to grow, with attempts to improve the methodology already underway. PMID:21686092

  1. Characterization of hydroxyurea resistance in C. elegans

    DEFF Research Database (Denmark)

    Brejning, Jeanette

    The soil nematode Caenorhabditis elegans has become a prominent model organism for studying aging and many age-related diseases. We use C. elegans to study the relationship between cancer and aging. To prevent cancer, cells are equipped with surveillance systems that detect damage and stop cells...... from dividing. These surveillance systems are collectively called cellular checkpoints. We have found that inactivation of certain checkpoint proteins, including p53, also cause resistance to the chemotherapeutic drug hydroxyurea (HU) that stalls replication. We have found that in C. elegans, HU...... inhibits ribonucleotide reductase (RNR). RNR is involved in synthesis of deoxyribonucleotide (dNTP) precursors for DNA replication and repair. Previously we have shown that inactivation of some checkpoint proteins can increase stress resistance and lifespan of C. elegans1. Interestingly, several genes...

  2. Scorpion antivenom effect of micropropagated Aristolochia elegans.

    Science.gov (United States)

    Izquierdo, Alejandro Mora; Zapata, Elsa Ventura; Jiménez-Ferrer, J Enrique; Muñoz, Crescencio Bazaldúa; Aparicio, Antonio Jiménez; Torres, Kalina Bermúdez; Torres, Lidia Osuna

    2010-08-01

    Aristolochia elegans Mast. (Aristolochiaceae) has been used to treat scorpion envenoming in Mexican traditional medicine. In vitro studies of the pharmacological activity of raw extracts from A. elegans roots have shown activity against scorpion bite. The aim of the present study was to determine for the first time the antagonistic effect of hexane and methanol extracts of the aerial parts and roots from micropropagated A. elegans plants in a model of isolated guinea-pig ileum contracted by scorpion bite. Results showed that the methanol extracts of aerial organs (74%) and roots (65%) of micropropagated plants have a similar antitoxin activity against scorpion poisoning to hexane extracts of wild plants (65%). These results suggest that using methanol extracts from the micropropagated plant material instead of wild plant root extracts from A. elegans is an alternative for treatment against scorpion bite symptoms, and will contribute to the conservation of this medicinal species.

  3. Toxicity of Naphthalene on Caenorhabditis elegans

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  4. Acute carbon dioxide avoidance in Caenorhabditis elegans

    OpenAIRE

    Hallem, Elissa A.; Sternberg, Paul W.

    2008-01-01

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

  5. A sleep state during C. elegans development

    OpenAIRE

    Nelson, Matthew D.; Raizen, David M.

    2013-01-01

    Caenorhabditis elegans is the simplest animal shown to sleep. It sleeps during lethargus, a larval transition stage. Behavior during lethargus has the sleep properties of a specific quiescent posture and elevated arousal threshold that are reversible to strong stimulation and of increased sleep drive following sleep deprivation. Genetic similarities between sleep regulation during C. elegans lethargus and sleep regulation in other animals point to a sleep state that was an evolutionarily ance...

  6. Locomotion of C. elegans in Structured Environments

    CERN Document Server

    Majmudar, Trushant S; Shelley, Mike; Zhang, Jun

    2010-01-01

    Undulatory locomotion of microorganisms like soil-dwelling worms and spermatozoa, in structured environments, is ubiquitous in nature. They navigate complex environments consisting of fluids and obstacles, negotiating hydrodynamic effects and geometrical constraints. Here, we show fluid dynamics videos of experiments and simulations of {\\textit {C. elegans}} moving in an array of micro-pillars. In addition, we show a video of transition from swimming to crawling in drop of {\\textit {C. elegans}}, where the fluid is wicking into agar.

  7. Cancer models in Caenorhabditis elegans.

    Science.gov (United States)

    Kirienko, Natalia V; Mani, Kumaran; Fay, David S

    2010-05-01

    Although now dogma, the idea that nonvertebrate organisms such as yeast, worms, and flies could inform, and in some cases even revolutionize, our understanding of oncogenesis in humans was not immediately obvious. Aided by the conservative nature of evolution and the persistence of a cohort of devoted researchers, the role of model organisms as a key tool in solving the cancer problem has, however, become widely accepted. In this review, we focus on the nematode Caenorhabditis elegans and its diverse and sometimes surprising contributions to our understanding of the tumorigenic process. Specifically, we discuss findings in the worm that address a well-defined set of processes known to be deregulated in cancer cells including cell cycle progression, growth factor signaling, terminal differentiation, apoptosis, the maintenance of genome stability, and developmental mechanisms relevant to invasion and metastasis. Copyright (c) 2010 Wiley-Liss, Inc.

  8. Biotransformation of a potent anabolic steroid, mibolerone, with Cunninghamella blakesleeana, C. echinulata, and Macrophomina phaseolina, and biological activity evaluation of its metabolites.

    Science.gov (United States)

    Siddiqui, Mahwish; Ahmad, Malik Shoaib; Wahab, Atia-Tul-; Yousuf, Sammer; Fatima, Narjis; Naveed Shaikh, Nimra; Rahman, Atta-Ur-; Choudhary, M Iqbal

    2017-01-01

    Seven metabolites were obtained from the microbial transformation of anabolic-androgenic steroid mibolerone (1) with Cunninghamella blakesleeana, C. echinulata, and Macrophomina phaseolina. Their structures were determined as 10β,17β-dihydroxy-7α,17α-dimethylestr-4-en-3-one (2), 6β,17β-dihydroxy-7α,17α-dimethylestr-4-en-3-one (3), 6β,10β,17β-trihydroxy-7α,17α-dimethylestr-4-en-3-one (4), 11β,17β-dihydroxy-(20-hydroxymethyl)-7α,17α-dimethylestr-4-en-3-one (5), 1α,17β-dihydroxy-7α,17α-dimethylestr-4-en-3-one (6), 1α,11β,17β-trihydroxy-7α,17α-dimethylestr-4-en-3-one (7), and 11β,17β-dihydroxy-7α,17α-dimethylestr-4-en-3-one (8), on the basis of spectroscopic studies. All metabolites, except 8, were identified as new compounds. This study indicates that C. blakesleeana, and C. echinulata are able to catalyze hydroxylation at allylic positions, while M. phaseolina can catalyze hydroxylation of CH2 and CH3 groups of substrate 1. Mibolerone (1) was found to be a moderate inhibitor of β-glucuronidase enzyme (IC50 = 42.98 ± 1.24 μM) during random biological screening, while its metabolites 2-4, and 8 were found to be inactive. Mibolerone (1) was also found to be significantly active against Leishmania major promastigotes (IC50 = 29.64 ± 0.88 μM). Its transformed products 3 (IC50 = 79.09 ± 0.06 μM), and 8 (IC50 = 70.09 ± 0.05 μM) showed a weak leishmanicidal activity, while 2 and 4 were found to be inactive. In addition, substrate 1 (IC50 = 35.7 ± 4.46 μM), and its metabolite 8 (IC50 = 34.16 ± 5.3 μM) exhibited potent cytotoxicity against HeLa cancer cell line (human cervical carcinoma). Metabolite 2 (IC50 = 46.5 ± 5.4 μM) also showed a significant cytotoxicity, while 3 (IC50 = 107.8 ± 4.0 μM) and 4 (IC50 = 152.5 ± 2.15 μM) showed weak cytotoxicity against HeLa cancer cell line. Compound 1 (IC50 = 46.3 ± 11.7 μM), and its transformed products 2 (IC50 = 43.3 ± 7.7 μM), 3 (IC50 = 65.6 ± 2.5 μM), and 4 (IC50 = 89.4 ± 2.7

  9. 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.

  10. 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.

  11. Phospholipase Cepsilon regulates ovulation in Caenorhabditis elegans.

    Science.gov (United States)

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

    2004-10-01

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

  12. A sleep state during C. elegans development.

    Science.gov (United States)

    Nelson, Matthew D; Raizen, David M

    2013-10-01

    Caenorhabditis elegans is the simplest animal shown to sleep. It sleeps during lethargus, a larval transition stage. Behavior during lethargus has the sleep properties of a specific quiescent posture and elevated arousal threshold that are reversible to strong stimulation and of increased sleep drive following sleep deprivation. Genetic similarities between sleep regulation during C. elegans lethargus and sleep regulation in other animals point to a sleep state that was an evolutionarily ancestor to sleep both in C. elegans and other animals. Recent publications have shed light on key questions in sleep biology: First, How is sleep regulated? Second, How is sensory information gated during sleep? Third, How is sleep homeostasis mediated? Fourth, What is the core function of sleep?

  13. Dopamine regulates body size in Caenorhabditis elegans.

    Science.gov (United States)

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

    2016-04-01

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

  14. Optogenetic mutagenesis in Caenorhabditis elegans

    Science.gov (United States)

    Noma, Kentaro; Jin, Yishi

    2015-01-01

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

  15. Ascaroside signaling in C. elegans.

    Science.gov (United States)

    Ludewig, Andreas H; Schroeder, Frank C

    2013-01-18

    Over the past 10 years, the relevance of small-molecule signaling for many aspects of C. elegans development and behavior has become apparent. One prominent group of small-molecule signals are the ascarosides, which control dauer entry and exit as well as a variety of sex-specific and social behaviors, including male attraction, hermaphrodite repulsion, olfactory plasticity, and aggregation. This wide range of biological functions is facilitated by a great diversity of ascaroside chemical structures. These are based on the sugar ascarylose, which is linked to fatty acid-like side chains of varying lengths and often decorated further with building blocks derived from amino acids, folate, and other primary metabolites. Different ascarosides or combinations of ascarosides mediate different phenotypes, and even small differences in chemical structures are often associated with strongly altered activity profiles. Additional complexity arises from concentration-dependent effects and synergism between different ascarosides. The ascarosides are sensed by several types of chemosensory head neurons, including the ASK, ASI, and ADL neurons as well as the male-specific CEM neurons. Ascaroside perception is mediated by diverse families of G-protein coupled membrane receptors that act upstream of conserved signal transduction pathways, including insulin/IGF-1 signaling and transforming growth factor beta (TGF-β) signaling. Biosynthesis of the ascarosides appears to integrate input from several primary metabolic pathways, including peroxisomal β-oxidation of long-chain fatty acids and amino acid catabolism. Life stage, sex, as well as food availability and other environmental factors affect ascaroside biosynthesis, suggesting that ascaroside signaling communicates detailed information about life history and metabolic state.

  16. Two New Oxoaporphine Alkaloids from Thalictrum elegans

    Institute of Scientific and Technical Information of China (English)

    梁志远; 杨小生; 汪冶; 郝小江

    2005-01-01

    Two new oxoaporphine alkaloids, 1,2,3,10-tetramethoxy-9-(2-hydroxy-4,5-dimethoxybenzyloxy)oxoaporphine (1) and 1,2,3,10-tetramethoxy-9-(4,5-dimethoxy-2-formylphenoxy)oxoaporphine (2), were isolated from Thalictrum elegans. Their structures were elucidated based on spectroscopic analysis including 1D, 2D NMR, IR and MS.

  17. The invertebrate Caenorhabditis elegans biosynthesizes ascorbate.

    Science.gov (United States)

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

    2015-03-01

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

  18. Guidelines for monitoring autophagy in Caenorhabditis elegans.

    Science.gov (United States)

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

    2015-01-01

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

  19. Characterization of the C. elegans erlin homologue

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    Hoegg Maja B

    2012-01-01

    Full Text Available Abstract Background Erlins are highly conserved proteins associated with lipid rafts within the endoplasmic reticulum (ER. Biochemical studies in mammalian cell lines have shown that erlins are required for ER associated protein degradation (ERAD of activated inositol-1,4,5-trisphosphate receptors (IP3Rs, implying that erlin proteins might negatively regulate IP3R signalling. In humans, loss of erlin function appears to cause progressive intellectual disability, motor dysfunction and joint contractures. However, it is unknown if defects in IP3R ERAD are the underlying cause of this disease phenotype, whether ERAD of activated IP3Rs is the only function of erlin proteins, and what role ERAD plays in regulating IP3R-dependent processes in the context of an intact animal or embryo. In this study, we characterize the erlin homologue of the nematode Caenorhabditis elegans and examine erlin function in vivo. We specifically set out to test whether C. elegans erlin modulates IP3R-dependent processes, such as egg laying, embryonic development and defecation rates. We also explore the possibility that erlin might play a more general role in the ERAD pathway of C. elegans. Results We first show that the C. elegans erlin homologue, ERL-1, is highly similar to mammalian erlins with respect to amino acid sequence, domain structure, biochemical properties and subcellular location. ERL-1 is present throughout the C. elegans embryo; in adult worms, ERL-1 appears restricted to the germline. The expression pattern of ERL-1 thus only partially overlaps with that of ITR-1, eliminating the possibility of ERL-1 being a ubiquitous and necessary regulator of ITR-1. We show that loss of ERL-1 does not affect overall phenotype, or alter brood size, embryonic development or defecation cycle length in either wild type or sensitized itr-1 mutant animals. Moreover we show that ERL-1 deficient worms respond normally to ER stress conditions, suggesting that ERL-1 is not an

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

    Science.gov (United States)

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

    2011-01-01

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

  1. Caenorhabditis elegans glia modulate neuronal activity and behavior

    OpenAIRE

    Randy F Stout; Alexei eVerkhratsky; Vladimir eParpura

    2014-01-01

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

  2. RNASeq in C. elegans Following Manganese Exposure.

    Science.gov (United States)

    Parmalee, Nancy L; Maqbool, Shahina B; Ye, Bin; Calder, Brent; Bowman, Aaron B; Aschner, Michael

    2015-08-06

    Manganese is a metal that is required for optimal biological functioning of organisms. Absorption, cellular import and export, and excretion of manganese are all tightly regulated. While some genes involved in regulation, such as DMT-1 and ferroportin, are known, it is presumed that many more are involved and as yet unknown. Excessive exposure to manganese, usually in industrial settings such as mining or welding, can lead to neurotoxicity and a condition known as manganism that closely resembles Parkinson's disease. Elucidating transcriptional changes following manganese exposure could lead to the development of biomarkers for exposure. This unit presents a protocol for RNA sequencing in the worm Caenorhabditis elegans to assay for transcriptional changes following exposure to manganese. This protocol is adaptable to any environmental exposure in C. elegans. The protocol results in counts of gene transcripts in control versus exposed conditions and a ranked list of differentially expressed genes for further study.

  3. Biosynthesis of the Caenorhabditis elegans dauer pheromone

    OpenAIRE

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

    2009-01-01

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

  4. The mevalonate pathway in C. Elegans

    Directory of Open Access Journals (Sweden)

    Rauthan Manish

    2011-12-01

    Full Text Available Abstract The mevalonate pathway in human is responsible for the synthesis of cholesterol and other important biomolecules such as coenzyme Q, dolichols and isoprenoids. These molecules are required in the cell for functions ranging from signaling to membrane integrity, protein prenylation and glycosylation, and energy homeostasis. The pathway consists of a main trunk followed by sub-branches that synthesize the different biomolecules. The majority of our knowledge about the mevalonate pathway is currently focused on the cholesterol synthesis branch, which is the target of the cholesterol-lowering statins; less is known about the function and regulation of the non-cholesterol-related branches. To study them, we need a biological system where it is possible to specifically modulate these metabolic branches individually or in groups. The nematode Caenorhabditis elegans (C. elegans is a promising model to study these non-cholesterol branches since its mevalonate pathway seems very well conserved with that in human except that it has no cholesterol synthesis branch. The simple genetic makeup and tractability of C. elegans makes it relatively easy to identify and manipulate key genetic components of the mevalonate pathway, and to evaluate the consequences of tampering with their activity. This general experimental approach should lead to new insights into the physiological roles of the non-cholesterol part of the mevalonate pathway. This review will focus on the current knowledge related to the mevalonate pathway in C. elegans and its possible applications as a model organism to study the non-cholesterol functions of this pathway.

  5. 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.

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

    Science.gov (United States)

    Petrushin, Alexey; Ferrara, Lorenzo; Blau, Axel

    2016-12-01

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

  7. Cyclin-dependent kinases in C. elegans

    Directory of Open Access Journals (Sweden)

    Boxem Mike

    2006-05-01

    Full Text Available Abstract Cell division is an inherent part of organismal development, and defects in this process can lead to developmental abnormalities as well as cancerous growth. In past decades, much of the basic cell-cycle machinery has been identified, and a major challenge in coming years will be to understand the complex interplay between cell division and multicellular development. Inevitably, this requires the use of more complex multicellular model systems. The small nematode Caenorhabditis elegans is an excellent model system to study the regulation of cell division in a multicellular organism, and is poised to make important contributions to this field. The past decade has already seen a surge in cell-cycle research in C. elegans, yielding information on the function of many basic cell-cycle regulators, and making inroads into the developmental control of cell division. This review focuses on the in vivo roles of cyclin-dependent kinases in C. elegans, and highlights novel findings implicating CDKs in coupling development to cell-cycle progression.

  8. 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.

  9. Acute carbon dioxide avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Hallem, Elissa A; Sternberg, Paul W

    2008-06-10

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

  10. Control of Neuronal Network in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Rahul Badhwar

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

  11. Toxicological Effects of Fullerenes on Caenorhabditis elegans

    Science.gov (United States)

    Schomaker, Justin; Snook, Renee; Howell, Carina

    2014-03-01

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

  12. Targeted genome engineering in Caenorhabditis elegans.

    Science.gov (United States)

    Chen, Xiangyang; Feng, Xuezhu; Guang, Shouhong

    2016-01-01

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

  13. Lectotypification of Salvia elegans (Lamiaceae) Lectotipificación de Salvia elegans (Lamiaceae)

    OpenAIRE

    Sabina I. Lara-Cabrera; María del Rosario García-Peña

    2008-01-01

    Salvia incarnata Cavanilles (1800) is an illegitimate name, for an earlier homonym by Etlinger (1777) already exists; it has therefore been substituted by Salvia elegans Vahl (1804). Both homotypic synonyms are herein lectotypified based on original material at MA collected by L. Née, and studied and annotated by A. J. CavanillesSalvia incarnata Cavanilles (1800) es un nombre ilegítimo, al preexistir un homónimo de Etlinger (1777); por ello, ha sido substituido por Salvia elegans Vahl (1804)....

  14. Stable nuclear transformation of Eudorina elegans

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    Lerche Kai

    2013-02-01

    Full Text Available Abstract Background A fundamental step in evolution was the transition from unicellular to differentiated, multicellular organisms. Volvocine algae have been used for several decades as a model lineage to investigate the evolutionary aspects of multicellularity and cellular differentiation. There are two well-studied volvocine species, a unicellular alga (Chlamydomonas reinhardtii and a multicellular alga with differentiated cell types (Volvox carteri. Species with intermediate characteristics also exist, which blur the boundaries between unicellularity and differentiated multicellularity. These species include the globular alga Eudorina elegans, which is composed of 16–32 cells. However, detailed molecular analyses of E. elegans require genetic manipulation. Unfortunately, genetic engineering has not yet been established for Eudorina, and only limited DNA and/or protein sequence information is available. Results Here, we describe the stable nuclear transformation of E. elegans by particle bombardment using both a chimeric selectable marker and reporter genes from different heterologous sources. Transgenic algae resistant to paromomycin were achieved using the aminoglycoside 3′-phosphotransferase VIII (aphVIII gene of Streptomyces rimosus, an actinobacterium, under the control of an artificial promoter consisting of two V. carteri promoters in tandem. Transformants exhibited an increase in resistance to paromomycin by up to 333-fold. Co-transformation with non-selectable plasmids was achieved with a rate of 50 - 100%. The luciferase (gluc gene from the marine copepod Gaussia princeps, which previously was engineered to match the codon usage of C. reinhardtii, was used as a reporter gene. The expression of gluc was mediated by promoters from C. reinhardtii and V. carteri. Heterologous heat shock promoters induced an increase in luciferase activity (up to 600-fold at elevated temperatures. Long-term stability and both constitutive and

  15. 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...

  16. 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

  17. Sensory processing by neural circuits in Caenorhabditis elegans.

    Science.gov (United States)

    Whittaker, Allyson J; Sternberg, Paul W

    2004-08-01

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

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

    Science.gov (United States)

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

    1992-01-01

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

  19. 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

  20. 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...

  1. 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.

  2. C. elegans locomotion analysis using algorithmic information theory.

    Science.gov (United States)

    Skandari, Roghieh; Le Bihan, Nicolas; Manton, Jonathan H

    2015-01-01

    This article investigates the use of algorithmic information theory to analyse C. elegans datasets. The ability of complexity measures to detect similarity in animals' behaviours is demonstrated and their strengths are compared to methods such as histograms. Introduced quantities are illustrated on a couple of real two-dimensional C. elegans datasets to investigate the thermotaxis and chemotaxis behaviours.

  3. C. elegans behavior of preference choice on bacterial food.

    Science.gov (United States)

    Abada, Emad Abd-elmoniem; Sung, Hyun; Dwivedi, Meenakshi; Park, Byung-Jae; Lee, Sun-Kyung; Ahnn, Joohong

    2009-09-01

    Caenorhabditis elegans is a free living soil nematode and thus in its natural habitat, C. elegans encounters many different species of soil bacteria. Although some soil bacteria may be excellent sources of nutrition for the worm, others may be pathogenic. Thus, we undertook a study to understand how C. elegans can identify their preferred food using a simple behavioral assay. We found that there are various species of soil bacteria that C. elegans prefers in comparison to the standard laboratory E. coli strain OP50. In particular, two bacterial strains, Bacillus mycoides and Bacillus soli, were preferred strains. Interestingly, the sole feeding of these bacteria to wild type animals results in extended lifespan through the activation of the autophagic process. Further studies will be required to understand the precise mechanism controlling the behavior of identification and selection of food in C. elegans.

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

    Science.gov (United States)

    Witting, Michael; Schmitt-Kopplin, Philippe

    2016-01-01

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

  5. [Non-alkaloid constituents of Gelsemium elegans].

    Science.gov (United States)

    Zhang, Binfeng; Chou, Guixin; Wang, Zhengtao

    2009-09-01

    To study the non-alkaloid chemical constituents of Gelsemium elegans. Compounds were isolated and purified by repeated column chromatography, and their structures were elucidated by spectroscopic methods. Ten compounds were isolated and their structures were identified as tamarixin (1), tamarixetin 3-O-beta-D-galactopyranoside (2), scopolin (3), scopoletin (4), uradine (5), caffeic acid (6), caffeic acid ethyl ester (7), ferulic acid ethyl ester (8), ethyl-alpha-D-fructofuranoside (9), and ethyl-beta-D-fructopyranoside (10). Compounds 1-3,5-10 are firstly isolated from this plant and compounds 1, 2, and 5-10 are isolated from the genus Gelsemium for the first time.

  6. CRISPR-Cas9-guided Genome Engineering in C. elegans

    Science.gov (United States)

    Kim, Hyun-Min; Colaiácovo, Monica P.

    2016-01-01

    The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system is successfully being used for efficient and targeted genome editing in various organisms including the nematode C. elegans. Recent studies developed various CRISPR-Cas9 approaches to enhance genome engineering via two major DNA double-strand break repair pathways: non-homologous end joining and homologous recombination. Here we describe a protocol for Cas9-mediated C. elegans genome editing together with single guide RNA (sgRNA) and repair template cloning and injection methods required for delivering Cas9, sgRNAs and repair template DNA into the C. elegans germline. PMID:27366893

  7. Alcohol disinhibition of behaviors in C. elegans.

    Directory of Open Access Journals (Sweden)

    Stephen M Topper

    Full Text Available Alcohol has a wide variety of effects on physiology and behavior. One of the most well-recognized behavioral effects is disinhibition, where behaviors that are normally suppressed are displayed following intoxication. A large body of evidence has shown that alcohol-induced disinhibition in humans affects attention, verbal, sexual, and locomotor behaviors. Similar behavioral disinhibition is also seen in many animal models of ethanol response, from invertebrates to mammals and primates. Here we describe several examples of disinhibition in the nematode C. elegans. The nematode displays distinct behavioral states associated with locomotion (crawling on land and swimming in water that are mediated by dopamine. On land, animals crawl and feed freely, but these behaviors are inhibited in water. We found that additional behaviors, including a variety of escape responses are also inhibited in water. Whereas alcohol non-specifically impaired locomotion, feeding, and escape responses in worms on land, alcohol specifically disinhibited these behaviors in worms immersed in water. Loss of dopamine signaling relieved disinhibition of feeding behavior, while loss of the D1-like dopamine receptor DOP-4 impaired the ethanol-induced disinhibition of crawling. The powerful genetics and simple nervous system of C. elegans may help uncover conserved molecular mechanisms that underlie alcohol-induced disinhibition of behaviors in higher animals.

  8. 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.

  9. Epigenetics in C. elegans: facts and challenges.

    Science.gov (United States)

    Wenzel, Dirk; Palladino, Francesca; Jedrusik-Bode, Monika

    2011-08-01

    Epigenetics is defined as the study of heritable changes in gene expression that are not accompanied by changes in the DNA sequence. Epigenetic mechanisms include histone post-translational modifications, histone variant incorporation, non-coding RNAs, and nucleosome remodeling and exchange. In addition, the functional compartmentalization of the nucleus also contributes to epigenetic regulation of gene expression. Studies on the molecular mechanisms underlying epigenetic phenomena and their biological function have relied on various model systems, including yeast, plants, flies, and cultured mammalian cells. Here we will expose the reader to the current understanding of epigenetic regulation in the roundworm C. elegans. We will review recent models of nuclear organization and its impact on gene expression, the biological role of enzymes modifying core histones, and the function of chromatin-associated factors, with special emphasis on Polycomb (PcG) and Trithorax (Trx-G) group proteins. We will discuss how the C. elegans model has provided novel insight into mechanisms of epigenetic regulation as well as suggest directions for future research.

  10. Lectotypification of Salvia elegans (Lamiaceae Lectotipificación de Salvia elegans (Lamiaceae

    Directory of Open Access Journals (Sweden)

    Sabina I. Lara-Cabrera

    2008-06-01

    Full Text Available Salvia incarnata Cavanilles (1800 is an illegitimate name, for an earlier homonym by Etlinger (1777 already exists; it has therefore been substituted by Salvia elegans Vahl (1804. Both homotypic synonyms are herein lectotypified based on original material at MA collected by L. Née, and studied and annotated by A. J. CavanillesSalvia incarnata Cavanilles (1800 es un nombre ilegítimo, al preexistir un homónimo de Etlinger (1777; por ello, ha sido substituido por Salvia elegans Vahl (1804. Se lectotipifican ambos sinónimos homotípicos con material original de L. Née, empleado por A. J. Cavanilles y que se conserva en MA.

  11. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    2013-01-01

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

  12. 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...

  13. Quantitative proteomics by amino acid labeling in C. elegans

    DEFF Research Database (Denmark)

    Fredens, Julius; Engholm-Keller, Kasper; Giessing, Anders;

    2011-01-01

    We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi-med......-mediated knockdown of the nuclear hormone receptor 49 in C. elegans. The combined use of quantitative proteomics and selective gene knockdown is a powerful tool for C. elegans biology.......We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi...

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

    Directory of Open Access Journals (Sweden)

    Avery Leon

    2010-06-01

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

  15. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

    2013-01-01

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

  16. Final Critical Habitat for the Bonytail Chub (Gila elegans)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — To provide the user with a general idea of areas where final critical habitat for Bonytail Chub (Gila elegans) occur based on the description provided in the Federal...

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

    Science.gov (United States)

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

    2009-08-01

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

  18. Transfer characteristics of a thermosensory synapse in Caenorhabditis elegans

    OpenAIRE

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

    2011-01-01

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

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

    Science.gov (United States)

    Lee, Raymond Y N; Sternberg, Paul W

    2003-01-01

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

  20. Genome-Wide Prediction of C. elegans Genetic Interactions

    OpenAIRE

    Zhong, Weiwei; Sternberg, Paul W.

    2006-01-01

    To obtain a global view of functional interactions among genes in a metazoan genome, we computationally integrated interactome data, gene expression data, phenotype data, and functional annotation data from three model organisms—Saccharomyces cerevisiae, Caenorhabditis elegans, and Drosophila melanogaster—and predicted genome-wide genetic interactions in C. elegans. The resulting genetic interaction network (consisting of 18,183 interactions) provides a framework for system-level understandin...

  1. 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...

  2. Genomic response of the nematode Caenorhabditis elegans to spaceflight

    Science.gov (United States)

    Selch, Florian; Higashibata, Akira; Imamizo-Sato, Mari; Higashitani, Atsushi; Ishioka, Noriaki; Szewczyk, Nathaniel J.; Conley, Catharine A.

    2008-01-01

    On Earth, it is common to employ laboratory animals such as the nematode Caenorhabditis elegans to help understand human health concerns. Similar studies in Earth orbit should help understand and address the concerns associated with spaceflight. The “International Caenorhabditis elegans Experiment FIRST” (ICE FIRST), was carried out onboard the Dutch Taxiflight in April of 2004 by an international collaboration of laboratories in France, Canada, Japan and the United States. With the exception of a slight movement defect upon return to Earth, the result of altered muscle development, no significant abnormalities were detected in spaceflown C. elegans. Work from Japan revealed apoptosis proceeds normally and work from Canada revealed no significant increase in the rate of mutation. These results suggest that C. elegans can be used to study non-lethal responses to spaceflight and can possibly be developed as a biological sensor. To further our understanding of C. elegans response to spaceflight, we examined the gene transcription response to the 10 days in space using a near full genome microarray analysis. The transcriptional response is consistent with the observed normal developmental timing, apoptosis, DNA repair, and altered muscle development. The genes identified as altered in response to spaceflight are enriched for genes known to be regulated, in C. elegans, in response to altered environmental conditions (Insulin and TGF-β regulated). These results demonstrate C. elegans can be used to study the effects of altered gravity and suggest that C. elegans responds to spaceflight by altering the expression of at least some of the same metabolic genes that are altered in response to differing terrestrial environments. PMID:18392117

  3. Characterisation of Caenorhabditis elegans sperm transcriptome and proteome

    OpenAIRE

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

    2014-01-01

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

  4. C. elegans in high-throughput drug discovery

    OpenAIRE

    O’Reilly, Linda P.; Cliff J Luke; Perlmutter, David H.; Silverman, Gary A.; Pak, Stephen C.

    2013-01-01

    C. elegans has proven to be a useful model organism for investigating molecular and cellular aspects of numerous human diseases. More recently, investigators have explored the use of this organism as a tool for drug discovery. Although earlier drug screens were labor-intensive and low in throughput, recent advances in high-throughput liquid workflows, imaging platforms and data analysis software have made C. elegans a viable option for automated high-throughput drug screens. This review will ...

  5. Microfluidic Approaches for Manipulating, Imaging, and Screening C. elegans

    Directory of Open Access Journals (Sweden)

    Bhagwati P. Gupta

    2016-07-01

    Full Text Available The nematode C. elegans (worm is a small invertebrate animal widely used in studies related to fundamental biological processes, disease modelling, and drug discovery. Due to their small size and transparent body, these worms are highly suitable for experimental manipulations. In recent years several microfluidic devices and platforms have been developed to accelerate worm handling, phenotypic studies and screens. Here we review major tools and briefly discuss their usage in C. elegans research.

  6. The C. elegans touch response facilitates escape from predacious fungi

    OpenAIRE

    Maguire, Sean M.; Clark, Christopher M.; Nunnari, John; Pirri, Jennifer K.; Alkema, Mark J.

    2011-01-01

    Predator-prey interactions are vital determinants in the natural selection of behavioral traits. However, we have few insights into both the neural mechanisms and the selective advantage of specific behavioral traits. Gentle touch to the anterior half of the body of Caenorhabditis elegans elicits an escape response in which the animal quickly reverses and suppresses exploratory head movements [1]. Even though the C. elegans touch response has provided one of the rare examples of how neural ne...

  7. 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

  8. Flow analysis of C. elegans swimming

    Science.gov (United States)

    Montenegro-Johnson, Thomas; Gagnon, David; Arratia, Paulo; Lauga, Eric

    2015-11-01

    Improved understanding of microscopic swimming has the potential to impact numerous biomedical and industrial processes. A crucial means of analyzing these systems is through experimental observation of flow fields, from which it is important to be able to accurately deduce swimmer physics such as power consumption, drag forces, and efficiency. We examine the swimming of the nematode worm C. elegans, a model system for undulatory micro-propulsion. Using experimental data of swimmer geometry and kinematics, we employ the regularized stokeslet boundary element method to simulate the swimming of this worm outside the regime of slender-body theory. Simulated flow fields are then compared with experimentally extracted values confined to the swimmer beat plane, demonstrating good agreement. We finally address the question of how to estimate three-dimensional flow information from two-dimensional measurements.

  9. Chemotaxis of crawling and swimming Caenorhabditis Elegans

    Science.gov (United States)

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

    2012-11-01

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

  10. Pattern formation during C. elegans vulval induction.

    Science.gov (United States)

    Wang, M; Sternberg, P W

    2001-01-01

    Studies of C. elegans vulval development provide insights into the process of pattern formation during animal development. The invariant pattern of vulval precursor cell fates is specified by the integration of at least two signaling systems. Recent findings suggest that multiple, partially redundant mechanisms are involved in patterning the vulval precursor cells. The inductive signal activates the LET-60/RAS signaling pathway and induces the 1 degree fate, whereas the lateral signal mediated by LIN-12/Notch is required for specification of the 2 degrees fate. Several regulatory pathways antagonize the RAS signaling pathway and specify the non-vulval 3 degrees fate in the absence of induction. The temporal and spatial regulation of VPC competence and production of the inductive and the lateral signal are precisely coordinated to ensure the wild-type vulval pattern.

  11. Transcriptional network underlying Caenorhabditis elegans vulval development.

    Science.gov (United States)

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

    2005-04-05

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

  12. Mainstreaming Caenorhabditis elegans in experimental evolution.

    Science.gov (United States)

    Gray, Jeremy C; Cutter, Asher D

    2014-03-01

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

  13. 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.

  14. Quantitative proteomics by amino acid labeling identifies novel NHR-49 regulated proteins in C. elegans

    DEFF Research Database (Denmark)

    Fredens, Julius; Færgeman, Nils J.

    2012-01-01

    in the nematode Caenorhabditis elegans. We have recently shown that C. elegans can be completely labeled with heavy-labeled lysine by feeding worms on prelabeled lysine auxotroph Escherichia coli for just one generation. We applied this methodology to examine the organismal response to functional loss or RNAi...... gene knockdown by RNAi provides a powerful tool with broad implications for C. elegans biology....

  15. The dynamics of the thermal memory of C. elegans

    Science.gov (United States)

    Ryu, William; Palanski, Konstantine; Bartumeus, Frederic; Nemenman, Ilya

    2014-03-01

    C. elegans has the capacity to learn associatively. For example, C. elegans associates temperature with food and performs thermotaxis towards this temperature when placed on a spatial thermal gradient. However, very little is understood how C. elegans acquires this thermal memory. We have developed a novel droplet-based microfluidic assay to measure the dynamics of the thermal memory of C. elegans. Individual animals are placed in an array of microdroplets on a slide, and a linear temperature gradient of 0.5 deg/cm is applied to the array. By measuring the swimming motions of C. elegans in the droplets, we show that they can perform thermotaxis. By calculating an index of this taxis behavior over time, we quantify the worm's thermal memory and measure its dynamics when the animals are exposed to different conditions of feeding and starvation. Over a time scale of hours, we find that the thermal preference of wild-type worms decays and will actually become inverted and that mutations in the insulin signaling pathway perturb the dynamics. This biphasic conditional association can be explained with a reinforcement learning model with independent reinforcement and avoidance pathways with distinct time scales. Human Frontier Science Program.

  16. Caenorhabditis elegans swimming in a saturated particulate system

    Science.gov (United States)

    Jung, Sunghwan

    2010-03-01

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

  17. 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.

  18. Radiation-induced genomic instability in Caenorhabditis elegans.

    Science.gov (United States)

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

    2012-10-01

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

  19. 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.

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

    Science.gov (United States)

    Holden-Dye, Lindy; Walker, Robert J

    2014-12-16

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

  1. A method for measuring fatty acid oxidation in C. elegans

    DEFF Research Database (Denmark)

    Elle, Ida Coordt; Rødkær, Steven Vestergaard; Fredens, Julius;

    2012-01-01

    The nematode C. elegans has during the past decade proven to be a valuable model organism to identify and examine molecular mechanisms regulating lipid storage and metabolism. While the primary approach has been to identify genes and pathways conferring alterations in lipid accumulation, only a few...... recent studies have recognized the central role of fatty acid degradation in cellular lipid homeostasis. In the present study, we show how complete oxidation of fatty acids can be determined in live C. elegans by examining oxidation of tritium-labeled fatty acids to tritiated H2O that can be measured......, the present methodology can be used to delineate the role of specific genes and pathways in the regulation of β-oxidation in C. elegans....

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

    Science.gov (United States)

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

    2011-06-07

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

  3. 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.

  4. CRISPR-Cas9-Guided Genome Engineering in C. elegans.

    Science.gov (United States)

    Kim, Hyun-Min; Colaiácovo, Monica P

    2016-07-01

    The CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system is successfully being used for efficient and targeted genome editing in various organisms, including the nematode C. elegans. Recent studies have developed various CRISPR-Cas9 approaches to enhance genome engineering via two major DNA double-strand break repair pathways: non-homologous end joining and homologous recombination. Here we describe a protocol for Cas9-mediated C. elegans genome editing together with single guide RNA (sgRNA) and repair template cloning, as well as injection methods required for delivering Cas9, sgRNAs, and repair template DNA into the C. elegans germline. © 2016 by John Wiley & Sons, Inc.

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

    Science.gov (United States)

    Powers, James A

    2010-06-01

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

  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. Proprioceptive coupling within motor neurons drives C. elegans forward locomotion

    Science.gov (United States)

    Wen, Quan; Po, Michelle; Hulme, Elizabeth; Chen, Sway; Liu, Xinyu; Kwok, Sen Wai; Gershow, Marc; Leifer, Andrew M; Butler, Victoria; Fang-Yen, Christopher; Kawano, Taizo; Schafer, William R; Whitesides, George

    2012-01-01

    Summary Locomotion requires coordinated motor activity throughout an animal’s body. In both vertebrates and invertebrates, chains of coupled Central Pattern Generators (CPGs) are commonly evoked to explain local rhythmic behaviors. In C. elegans, we report that proprioception within the motor circuit is responsible for propagating and coordinating rhythmic undulatory waves from head to tail during forward movement. Proprioceptive coupling between adjacent body regions transduces rhythmic movement initiated near the head into bending waves driven along the body by a chain of reflexes. Using optogenetics and calcium imaging to manipulate and monitor motor circuit activity of moving C. elegans held in microfluidic devices, we found that the B-type cholinergic motor neurons transduce the proprioceptive signal. In C. elegans, a sensorimotor feedback loop operating within a specific type of motor neuron both drives and organizes body movement. PMID:23177960

  8. High-throughput screening in the C. elegans nervous system.

    Science.gov (United States)

    Kinser, Holly E; Pincus, Zachary

    2016-06-03

    The nematode Caenorhabditis elegans is widely used as a model organism in the field of neurobiology. The wiring of the C. elegans nervous system has been entirely mapped, and the animal's optical transparency allows for in vivo observation of neuronal activity. The nematode is also small in size, self-fertilizing, and inexpensive to cultivate and maintain, greatly lending to its utility as a whole-animal model for high-throughput screening (HTS) in the nervous system. However, the use of this organism in large-scale screens presents unique technical challenges, including reversible immobilization of the animal, parallel single-animal culture and containment, automation of laser surgery, and high-throughput image acquisition and phenotyping. These obstacles require significant modification of existing techniques and the creation of new C. elegans-based HTS platforms. In this review, we outline these challenges in detail and survey the novel technologies and methods that have been developed to address them.

  9. Dynamical complexity in the C.elegans neural network

    Science.gov (United States)

    Antonopoulos, C. G.; Fokas, A. S.; Bountis, T. C.

    2016-09-01

    We model the neuronal circuit of the C.elegans soil worm in terms of a Hindmarsh-Rose system of ordinary differential equations, dividing its circuit into six communities which are determined via the Walktrap and Louvain methods. Using the numerical solution of these equations, we analyze important measures of dynamical complexity, namely synchronicity, the largest Lyapunov exponent, and the ΦAR auto-regressive integrated information theory measure. We show that ΦAR provides a useful measure of the information contained in the C.elegans brain dynamic network. Our analysis reveals that the C.elegans brain dynamic network generates more information than the sum of its constituent parts, and that attains higher levels of integrated information for couplings for which either all its communities are highly synchronized, or there is a mixed state of highly synchronized and desynchronized communities.

  10. Achieving immortality in the C. elegans germline.

    Science.gov (United States)

    Smelick, Chris; Ahmed, Shawn

    2005-01-01

    Germline immortality is a topic that has intrigued theoretical biologists interested in aging for over a century. The germ cell lineage can be passed from one generation to the next, indefinitely. In contrast, somatic cells are typically only needed for a single generation and are then discarded. Germ cells may, therefore, harbor rejuvenation mechanisms that enable them to proliferate for eons. Such processes are thought to be either absent from or down-regulated in somatic cells, although cell non-autonomous forms of rejuvenation are formally possible. A thorough description of mechanisms that foster eternal youth in germ cells is lacking. The mysteries of germline immortality are being addressed in the nematode Caenorhabditis elegans by studying mutants that reproduce normally for several generations but eventually become sterile. The mortal germline mutants probably become sterile as a consequence of accumulating various forms of heritable cellular damage. Such mutants are abundant, indicating that several different biochemical pathways are required to rejuvenate the germline. Thus, forward genetics should help to define mechanisms that enable the germline to achieve immortality.

  11. DNA methylation in tissues of Chamaedorea elegans

    Institute of Scientific and Technical Information of China (English)

    LU Yongquan; QING Jia; LI Haiying; TONG Zaikang

    2012-01-01

    DNA methylation plays a crucial role in regulating plant development and tissue differentiation.In this study,we compared the methylation levels in leaf,root,and stem in Chamaedorea elegans by using the technique of methylation-sensitive amplified fragment length polymorphism AFLP.Over 19% (42/220) bases were uniformly methylated in these tissues.The percentages of polymorphism resulting from varied methylation in mature leaf (L1),young leaf (L2),baby leaf (L3),stem (S),young root (R1) and lignified root (R2) were 29.5%,29.0%,27.1%,30.7%,63.0% and 28.3%,respectively.The numbers of polymorphic loci detected in the leaves of three developmental stages were similar,ranging from 20 to 30.In contrast,roots at the two developmental stages differed greatly,with 145 polymorphic loci detected in R1 and 27 in R2.Our results suggest that the methylation level in leaves slightly increases with aging,while that in roots decreases dramatically with aging.

  12. Caenorhabditis elegans vulval cell fate patterning

    Science.gov (United States)

    Félix, Marie-Anne

    2012-08-01

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

  13. Functional genomic analysis of C. elegans molting.

    Directory of Open Access Journals (Sweden)

    Alison R Frand

    2005-10-01

    Full Text Available Although the molting cycle is a hallmark of insects and nematodes, neither the endocrine control of molting via size, stage, and nutritional inputs nor the enzymatic mechanism for synthesis and release of the exoskeleton is well understood. Here, we identify endocrine and enzymatic regulators of molting in C. elegans through a genome-wide RNA-interference screen. Products of the 159 genes discovered include annotated transcription factors, secreted peptides, transmembrane proteins, and extracellular matrix enzymes essential for molting. Fusions between several genes and green fluorescent protein show a pulse of expression before each molt in epithelial cells that synthesize the exoskeleton, indicating that the corresponding proteins are made in the correct time and place to regulate molting. We show further that inactivation of particular genes abrogates expression of the green fluorescent protein reporter genes, revealing regulatory networks that might couple the expression of genes essential for molting to endocrine cues. Many molting genes are conserved in parasitic nematodes responsible for human disease, and thus represent attractive targets for pesticide and pharmaceutical development.

  14. ASI regulates satiety quiescence in C. elegans.

    Science.gov (United States)

    Gallagher, Thomas; Kim, Jeongho; Oldenbroek, Marieke; Kerr, Rex; You, Young-Jai

    2013-06-05

    In Caenorhabditis elegans, satiety quiescence mimics behavioral aspects of satiety and postprandial sleep in mammals. On the basis of calcium-imaging, genetics, and behavioral studies, here we report that a pair of amphid neurons, ASI, is activated by nutrition and regulates worms' behavioral states specifically promoting satiety quiescence; ASI inhibits the switch from quiescence to dwelling (a browsing state) and accelerates the switch from dwelling to quiescence. The canonical TGFβ pathway, whose ligand is released from ASI, regulates satiety quiescence. The mutants of a ligand, a receptor and SMADs in the TGFβ pathway all eat more and show less quiescence than wild-type. The TGFβ receptor in downstream neurons RIM and RIC is sufficient for worms to exhibit satiety quiescence, suggesting neuronal connection from ASI to RIM and RIC is essential for feeding regulation through the TGFβ pathway. ASI also regulates satiety quiescence partly through cGMP signaling; restoring cGMP signaling in ASI rescues the satiety quiescence defect of cGMP signaling mutants. From these results, we propose that TGFβ and cGMP pathways in ASI connect nutritional status to promotion of satiety quiescence, a sleep-like behavioral state.

  15. Acetylcholinesterase genes in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Combes, D; Fedon, Y; Toutant, J P; Arpagaus, M

    2001-01-01

    Acetylcholinesterase (AChE, EC 3.1.1.7) is responsible for the termination of cholinergic nerve transmission. It is the target of organophosphates and carbamates, two types of chemical pesticides being used extensively in agriculture and veterinary medicine against insects and nematodes. Whereas there is usually one single gene encoding AChE in insects, nematodes are one of the rare phyla where multiple ace genes have been unambiguously identified. We have taken advantage of the nematode Caenorhabditis elegans model to identify the four genes encoding AChE in this species. Two genes, ace-1 and ace-2, encode two major AChEs with different pharmacological properties and tissue repartition: ace-1 is expressed in muscle cells and a few neurons, whereas ace-2 is mainly expressed in motoneurons. ace-3 represents a minor proportion of the total AChE activity and is expressed only in a few cells, but it is able to sustain double null mutants ace-1; ace-2. It is resistant to usual cholinesterase inhibitors. ace-4 was transcribed but the corresponding enzyme was not detected in vivo.

  16. Locomotion of C elegans in structured environments

    Science.gov (United States)

    Majmudar, Trushant; Keaveny, Eric; Shelley, Michael; Zhang, Jun

    2010-11-01

    Undulatory locomotion of microorganisms like soil-dwelling worms and sperm, in structured environments, is ubiquitous in nature. They navigate complex environments consisting of fluids and obstacles, negotiating hydrodynamic effects and geometrical constraints. Here we report experimental observations on the locomotion of C elegans swimming in arrays of micro-pillars in square lattices, with different lattice spacing. We observe that the worm employs a number of different locomotion strategies depending on the lattice spacing. As observed previously in the literature, we uncover regimes of enhanced locomotion, where the velocity is much higher than the free-swimming velocity. In addition, we also observe changes in frequency, velocity, and the gait of the worm as a function of lattice spacing. We also track the worm over time and find that it exhibits super-diffusive behavior and covers a larger area by utilizing the obstacles. These results may have significant impact on the foraging behavior of the worm in its natural environment. Our experimental approach, in conjunction with modeling and simulations, allows us to disentangle the effects of structure and hydrodynamics for an undulating microorganism.

  17. Chromosome I duplications in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  18. Biosynthesis of the Caenorhabditis elegans dauer pheromone.

    Science.gov (United States)

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

    2009-02-10

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

  19. Malignant worms: what cancer research can learn from C. elegans.

    Science.gov (United States)

    Saito, R Mako; van den Heuvel, Sander

    2002-01-01

    Developmental processes in the nematode C. elegans are controlled by pathways of gene functions that are analogous to those used in mammals. Hence, genetic studies in C. elegans have helped build the frameworks for these regulatory pathways. Many homologs of human genes that are targets for mutation in cancer have been found to function at distinct steps within such genetic pathways. This way, studies in C. elegans have provided important clues about the functions of human oncogenes and tumor suppressors. Understanding how human cancer genes function and act in signaling cascades is of great importance. This information reveals what kind of molecular changes contribute to the process of cell transformation. Moreover, additional candidate oncogenes and tumor suppressors may be revealed by identifying the functional partners of genes with an established role in cancer. Furthermore, identifying a cascade of gene functions increases the number of potential targets for therapeutic intervention, as blocking either one of multiple genes may interfere with signal transduction through the pathway. Simultaneous approaches in a number of different model systems act synergistically in solving pathways of gene functions. By using multiple models, the field takes advantage of the strengths of each system and circumvents its limitations. As one of the most powerful genetic animal systems, C. elegans will continue to reveal new mammalian signaling components. In addition, now that the C. elegans genome sequence has been completed, an increasing number of researchers are likely to discover homologs of human disease genes in the nematode and to analyze gene function in the worm model. Combined with the great potential of this animal in drug screens, it is simple to predict that C. elegans will worm its way deeper and deeper into cancer research.

  20. 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.

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

    Science.gov (United States)

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

    2015-06-01

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

  2. Rhino-orbitocerebral mucormycosis caused by Apophysomyces elegans.

    Science.gov (United States)

    Liang, Kimberly P; Tleyjeh, Imad M; Wilson, Walter R; Roberts, Glenn D; Temesgen, Zelalem

    2006-03-01

    Rhino-orbitocerebral mucormycosis (ROCM) caused by more common zygomycetes (e.g., Mucor) is known to cause rapidly fatal infections in immunocompromised patients. Apophysomyces elegans is an emerging zygomycete that has been reported to cause invasive cutaneous and rhino-orbitocerebral infections in immunocompetent individuals. Limited data exist describing the syndrome of ROCM caused by A. elegans. We describe a recent case and performed a comprehensive literature review to delineate the clinical characteristics of ROCM caused by A. elegans. Our case is a 50-year-old man with diabetes mellitus who presented with facial pain and right eye proptosis. Endoscopic sinus sampling revealed A. elegans. He was treated with liposomal amphotericin B and multiple debridements, with no disease on 1.5-year follow-up examination. Seven cases were identified on literature review, including the present case. Most patients (86%) were male, with a mean age of 40 years. Most patients (71%) did not have predisposing medical conditions. Three patients had predisposing head trauma. All presented with facial and/or periorbital pain. All had magnetic resonance imaging or computed tomography of the head showing intraorbital and/or sinus inflammation. Diagnosis was confirmed by histopathology and deep tissue culture in all cases. All patients required eye exenteration and extensive surgical debridement, in addition to intravenous amphotericin B. Six of the seven patients (86%) recovered. ROCM caused by A. elegans is rarely reported in the literature. Most such infections occurred in immunocompetent patients, often after facial trauma. Survival in ROCM caused by A. elegans is favorable in reported cases, with prompt surgical debridement and antifungal therapy.

  3. Genome-wide prediction of C. elegans genetic interactions.

    Science.gov (United States)

    Zhong, Weiwei; Sternberg, Paul W

    2006-03-10

    To obtain a global view of functional interactions among genes in a metazoan genome, we computationally integrated interactome data, gene expression data, phenotype data, and functional annotation data from three model organisms-Saccharomyces cerevisiae, Caenorhabditis elegans, and Drosophila melanogaster-and predicted genome-wide genetic interactions in C. elegans. The resulting genetic interaction network (consisting of 18,183 interactions) provides a framework for system-level understanding of gene functions. We experimentally tested the predicted interactions for two human disease-related genes and identified 14 new modifiers.

  4. 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.

  5. C. elegans as a model system for Parkinson disease

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Parkinson disease( PD) is characterized by the selective loss of dopaminergic neurons in the substantia nigra.Although investigation in mammalian animal models of PD has enhanced our understanding of PD, the complexity of the mammalian nervous system and our inability to visualize DA neurons in vivo restricts the advances in elucidating the molecular mechanisms of PD. Conservation between C. elegans and mammals in genomic, biosynthetic and metabolic pathways as well as the advantages of observing DA neurons morphology in vivo and the ease of transgenic and genetic manipulation make C. elegans an excellent model organism for PD.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-10-01

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

  7. Searching for the elusive mitochondrial longevity signal in C. elegans.

    Science.gov (United States)

    Bennett, Christopher F; Choi, Haeri; Kaeberlein, Matt

    2014-01-01

    There is a growing list of examples where perturbed mitochondrial function is associated with increased longevity, yet the exact mechanisms have remained elusive. This phenomenon was first documented, and has been studied most extensively, in C. elegans. One prominent model proposed that lifespan extension resulting from electron transport chain inhibition is due to induction of the mitochondrial unfolded protein response. This model requires revision in light of recent data showing that the mitochondrial unfolded protein response, as defined by the field, is neither necessary nor sufficient for lifespan extension in C. elegans. Several additional factors have been proposed to underlie this lifespan extension, which is likely to be multifactorial and complex.

  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. Evolutionary innovation of the excretory system in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Xiaodong; Chamberlin, Helen M

    2004-03-01

    The evolution of complexity relies on changes that result in new gene functions. Here we show that the unique morphological and functional features of the excretory duct cell in C. elegans result from the gain of expression of a single gene. Our results show that innovation can be achieved by altered expression of a transcription factor without coevolution of all target genes.

  10. Two new benzofuran lignan glycosides from Gelsemium elegans

    Institute of Scientific and Technical Information of China (English)

    Wei Hua; Qing Chun Zhao; Jia Yang; Guo Bing Shi; Li Jun Wu; Tao Guo

    2008-01-01

    Two new benzofuran lignan glycosides,gelsemiunoside A and B,were isolated from the whole plant of Gelsemium elegans Benth.Their structures were elucidated on the basis of spectroscopic evidence.Furthermore,gelsemiunoside A and B were shown a potent cytotoxic activity by suppressing the proliferation of A375-S2 cells.

  11. Single-copy insertion of transgenes in Caenorhabditis elegans

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  12. Biophysical and biological meanings of healthspan from C. elegans cohort

    Energy Technology Data Exchange (ETDEWEB)

    Suda, Hitoshi, E-mail: suda@tsc.u-tokai.ac.jp

    2014-09-12

    Highlights: • We focus on a third factor, noise, as well as on genetic and environmental factors. • C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. • An amplification of ATP noise was clearly evident from around the onset of biodemographic aging. • The extension of timing of noise amplification may contribute to effectively extending the healthspan. • The same mechanism of the mean lifespan extension in C. elegans may be realized in humans. - Abstract: Lifespan among individuals ranges widely in organisms from yeast to mammals, even in an isogenic cohort born in a nearly uniform environment. Needless to say, genetic and environmental factors are essential for aging and lifespan, but in addition, a third factor or the existence of a stochastic element must be reflected in aging and lifespan. An essential point is that lifespan or aging is an unpredictable phenomenon. The present study focuses on elucidating the biophysical and biological meanings of healthspan that latently indwells a stochastic nature. To perform this purpose, the nematode Caenorhabditis elegans served as a model animal. C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. Then, utilizing this phenomenon, we clarified a mechanism of healthspan extension by measuring the single-worm ATP and estimating the ATP noise (or the variability of the ATP content) among individual worms and by quantitatively analyzing biodemographic data with the lifespan equation that was derived from a fluctuation theory.

  13. Cell fate determination in the Caenorhabditis elegans epidermal lineages

    NARCIS (Netherlands)

    Soete, G.A.J.

    2007-01-01

    The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly compl

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Science.gov (United States)

    Ardiel, Evan L.; Rankin, Catharine H.

    2010-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

  17. The C. elegans rab family: identification, classification and toolkit construction.

    Science.gov (United States)

    Gallegos, Maria E; Balakrishnan, Sanjeev; Chandramouli, Priya; Arora, Shaily; Azameera, Aruna; Babushekar, Anitha; Bargoma, Emilee; Bokhari, Abdulmalik; Chava, Siva Kumari; Das, Pranti; Desai, Meetali; Decena, Darlene; Saramma, Sonia Dev Devadas; Dey, Bodhidipra; Doss, Anna-Louise; Gor, Nilang; Gudiputi, Lakshmi; Guo, Chunyuan; Hande, Sonali; Jensen, Megan; Jones, Samantha; Jones, Norman; Jorgens, Danielle; Karamchedu, Padma; Kamrani, Kambiz; Kolora, Lakshmi Divya; Kristensen, Line; Kwan, Kelly; Lau, Henry; Maharaj, Pranesh; Mander, Navneet; Mangipudi, Kalyani; Menakuru, Himabindu; Mody, Vaishali; Mohanty, Sandeepa; Mukkamala, Sridevi; Mundra, Sheena A; Nagaraju, Sudharani; Narayanaswamy, Rajhalutshimi; Ndungu-Case, Catherine; Noorbakhsh, Mersedeh; Patel, Jigna; Patel, Puja; Pendem, Swetha Vandana; Ponakala, Anusha; Rath, Madhusikta; Robles, Michael C; Rokkam, Deepti; Roth, Caroline; Sasidharan, Preeti; Shah, Sapana; Tandon, Shweta; Suprai, Jagdip; Truong, Tina Quynh Nhu; Uthayaruban, Rubatharshini; Varma, Ajitha; Ved, Urvi; Wang, Zeran; Yu, Zhe

    2012-01-01

    Rab monomeric GTPases regulate specific aspects of vesicle transport in eukaryotes including coat recruitment, uncoating, fission, motility, target selection and fusion. Moreover, individual Rab proteins function at specific sites within the cell, for example the ER, golgi and early endosome. Importantly, the localization and function of individual Rab subfamily members are often conserved underscoring the significant contributions that model organisms such as Caenorhabditis elegans can make towards a better understanding of human disease caused by Rab and vesicle trafficking malfunction. With this in mind, a bioinformatics approach was first taken to identify and classify the complete C. elegans Rab family placing individual Rabs into specific subfamilies based on molecular phylogenetics. For genes that were difficult to classify by sequence similarity alone, we did a comparative analysis of intron position among specific subfamilies from yeast to humans. This two-pronged approach allowed the classification of 30 out of 31 C. elegans Rab proteins identified here including Rab31/Rab50, a likely member of the last eukaryotic common ancestor (LECA). Second, a molecular toolset was created to facilitate research on biological processes that involve Rab proteins. Specifically, we used Gateway-compatible C. elegans ORFeome clones as starting material to create 44 full-length, sequence-verified, dominant-negative (DN) and constitutive active (CA) rab open reading frames (ORFs). Development of this toolset provided independent research projects for students enrolled in a research-based molecular techniques course at California State University, East Bay (CSUEB).

  18. On the growth rate of the foliicolous lichen Strigula elegans

    NARCIS (Netherlands)

    Wilde-Duyfjes, de B.E.E.

    1967-01-01

    The diametral growth rate of the foliicolous lichen Strigula elegans (Fée) Müll. Arg., measured under natural conditions in the African tropical rainforest, has been established to amount to (0.7-)3-3-6(-8) mm annually. As compared to the diametral growth rate of lichens from temperate regions, whic

  19. 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.

  20. Molecular profiling of mitochondrial dysfunction in Caenorhabditis elegans.

    Science.gov (United States)

    Polyak, Erzsebet; Zhang, Zhe; Falk, Marni J

    2012-01-01

    Cellular effects of primary mitochondrial dysfunction, as well as potential mitochondrial disease therapies, can be modeled in living animals such as the microscopic nematode, Caenorhabditis elegans. In particular, molecular analyses can provide substantial insight into the mechanism by which genetic and/or pharmacologic manipulations alter mitochondrial function. The relative expression of individual genes across both nuclear and mitochondrial genomes, as well as relative quantitation of mitochondrial DNA content, can be readily performed by quantitative real-time PCR (qRT-PCR) analysis of C. elegans. Additionally, microarray expression profiling offers a powerful tool by which to survey the global genetic consequences of various causes of primary mitochondrial dysfunction and potential therapeutic interventions at both the single gene and integrated pathway level. Here, we describe detailed protocols for RNA and DNA isolation from whole animal populations in C. elegans, qRT-PCR analysis of both nuclear and mitochondrial genes, and global nuclear genome expression profiling using the Affymetrix GeneChip C. elegans Genome Array.

  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 compl

  2. Population dynamics of Lanyu Scops Owls (Otus elegans botelensis)

    Science.gov (United States)

    L. L. Severinghaus

    1997-01-01

    Monthly visits to Lanyu Island have been made to study Lanyu Scops Owls (Otus elegans botelensis) since 1986. This population has been surveyed by regular census and playback counts, by color banding, by monitoring the survival, reproduction and movements of individual owls, and by mapping and documenting the change in nest trees.

  3. Allyl isothiocyanate induced stress response in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Saini AkalRachna K

    2011-11-01

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

  4. 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

  5. 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.

  6. Lessons from bloodless worms: heme homeostasis in C. elegans.

    Science.gov (United States)

    Sinclair, Jason; Hamza, Iqbal

    2015-06-01

    Heme is an essential cofactor for proteins involved in diverse biological processes such as oxygen transport, electron transport, and microRNA processing. Free heme is hydrophobic and cytotoxic, implying that specific trafficking pathways must exist for the delivery of heme to target hemoproteins which reside in various subcellular locales. Although heme biosynthesis and catabolism have been well characterized, the pathways for trafficking heme within and between cells remain poorly understood. Caenorhabditis elegans serves as a unique animal model for uncovering these pathways because, unlike vertebrates, the worm lacks enzymes to synthesize heme and therefore is crucially dependent on dietary heme for sustenance. Using C. elegans as a genetic animal model, several novel heme trafficking molecules have been identified. Importantly, these proteins have corresponding homologs in vertebrates underscoring the power of using C. elegans, a bloodless worm, in elucidating pathways in heme homeostasis and hematology in humans. Since iron deficiency and anemia are often exacerbated by parasites such as helminths and protozoa which also rely on host heme for survival, C. elegans will be an ideal model to identify anti-parasitic drugs that target heme transport pathways unique to the parasite.

  7. Plant adaptogens increase lifespan and stress resistance in C. elegans

    NARCIS (Netherlands)

    Wiegant, F.A.C.; Surinova, S.; Ytsma, E.; Langelaar-Makkinje, M.; Wikman, G.; Post, J.A.

    2008-01-01

    Extracts of plant adaptogens such as Eleutherococcus senticosus (or Acanthopanax senticosus) and Rhodiola rosea can increase stress resistance in several model systems. We now show that both extracts also increase the mean lifespan of the nematode C. elegans in a dose-dependent way. In

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

    Science.gov (United States)

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

    2013-11-29

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

  9. Silicon-inducible defenses of Zinnia elegans against Myzus persicae

    Science.gov (United States)

    Several examples exist of silicon (Si) amendment inducing plant chemical defenses against plant pathogens, but few studies have focused on Si-induced defenses against phloem-feeding herbivores. The current study examined Si treatment of Zinnia elegans Jacq. cv. Oklahoma White (Compositae) on the pe...

  10. 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...

  11. The C. elegans touch response facilitates escape from predacious fungi.

    Science.gov (United States)

    Maguire, Sean M; Clark, Christopher M; Nunnari, John; Pirri, Jennifer K; Alkema, Mark J

    2011-08-09

    Predator-prey interactions are vital determinants in the natural selection of behavioral traits. Gentle touch to the anterior half of the body of Caenorhabditis elegans elicits an escape response in which the animal quickly reverses and suppresses exploratory head movements [1, 2]. Here, we investigate the ecological significance of the touch response in predator-prey interactions between C. elegans and predacious fungi that catch nematodes using constricting hyphal rings. We show that the constricting rings of Drechslerella doedycoides catch early larval stages with a diameter similar to the trap opening. There is a delay between the ring entry and ring closure, which allows the animal to withdraw from the trap before being caught. Mutants that fail to suppress head movements in response to touch are caught more efficiently than the wild-type. This demonstrates that the coordination of motor programs allows C. elegans to smoothly retract from a fungal noose and evade capture. Our results suggest that selective pressures imposed by predacious fungi have shaped the evolution of C. elegans escape behavior.

  12. Lipid droplets as ubiquitous fat storage organelles in C. elegans

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    Guo Fengli

    2010-12-01

    Full Text Available Abstract Background Lipid droplets are a class of eukaryotic cell organelles for storage of neutral fat such as triacylglycerol (TAG and cholesterol ester (CE. We and others have recently reported that lysosome-related organelles (LROs are not fat storage structures in the nematode C. elegans. We also reported the formation of enlarged lipid droplets in a class of peroxisomal fatty acid β-oxidation mutants. In the present study, we seek to provide further evidence on the organelle nature and biophysical properties of fat storage structures in wild-type and mutant C. elegans. Results In this study, we provide biochemical, histological and ultrastructural evidence of lipid droplets in wild-type and mutant C. elegans that lack lysosome related organelles (LROs. The formation of lipid droplets and the targeting of BODIPY fatty acid analogs to lipid droplets in live animals are not dependent on lysosomal trafficking or peroxisome dysfunction. However, the targeting of Nile Red to lipid droplets in live animals occurs only in mutants with defective peroxisomes. Nile Red labelled-lipid droplets are characterized by a fluorescence emission spectrum distinct from that of Nile Red labelled-LROs. Moreover, we show that the recently developed post-fix Nile Red staining method labels lipid droplets exclusively. Conclusions Our results demonstrate lipid droplets as ubiquitous fat storage organelles and provide a unified explanation for previous studies on fat labelling methods in C. elegans. These results have important applications to the studies of fat storage and lipid droplet regulation in the powerful genetic system, C. elegans.

  13. Mitochondrial stress extends lifespan in C. elegans through neuronal hormesis.

    Science.gov (United States)

    Maglioni, Silvia; Schiavi, Alfonso; Runci, Alessandra; Shaik, Anjumara; Ventura, Natascia

    2014-08-01

    Progressive neuronal deterioration accompanied by sensory functions decline is typically observed during aging. On the other hand, structural or functional alterations of specific sensory neurons extend lifespan in the nematode Caenorhabditis elegans. Hormesis is a phenomenon by which the body benefits from moderate stress of various kinds which at high doses are harmful. Several studies indicate that different stressors can hormetically extend lifespan in C. elegans and suggest that hormetic effects could be exploited as a strategy to slow down aging and the development of age-associated (neuronal) diseases in humans. Mitochondria play a central role in the aging process and hormetic-like bimodal dose-response effects on C. elegans lifespan have been observed following different levels of mitochondrial stress. Here we tested the hypothesis that mitochondrial stress may hormetically extend C. elegans lifespan through subtle neuronal alterations. In support of our hypothesis we find that life-lengthening dose of mitochondrial stress reduces the functionality of a subset of ciliated sensory neurons in young animals. Notably, the same pro-longevity mitochondrial treatments rescue the sensory deficits in old animals. We also show that mitochondrial stress extends C. elegans lifespan acting in part through genes required for the functionality of those neurons. To our knowledge this is the first study describing a direct causal connection between sensory neuron dysfunction and extended longevity following mitochondrial stress. Our work supports the potential anti-aging effect of neuronal hormesis and open interesting possibility for the development of therapeutic strategy for age-associated neurodegenerative disorders.

  14. A monoclonal antibody toolkit for C. elegans.

    Directory of Open Access Journals (Sweden)

    Gayla Hadwiger

    working in whole mount immunocytochemistry, most of these antibodies work on western blots and thus should be of use for biochemical fractionation studies. CONCLUSIONS/SIGNIFICANCE: We have produced a set of monoclonal antibodies to subcellular components of the nematode C. elegans for the research community. These reagents are being made available through the Developmental Studies Hybridoma Bank (DSHB.

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

    Science.gov (United States)

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

    2006-08-04

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

  16. Stimulation of Host Immune Defenses by a Small Molecule Protects C. elegans from Bacterial Infection

    OpenAIRE

    Read Pukkila-Worley; Rhonda Feinbaum; Kirienko, Natalia V; Jonah Larkins-Ford; Conery, Annie L.; Ausubel, Frederick M.

    2012-01-01

    The nematode Caenorhabditis elegans offers currently untapped potential for carrying out high-throughput, live-animal screens of low molecular weight compound libraries to identify molecules that target a variety of cellular processes. We previously used a bacterial infection assay in C. elegans to identify 119 compounds that affect host-microbe interactions among 37,214 tested. Here we show that one of these small molecules, RPW-24, protects C. elegans from bacterial infection by stimulating...

  17. The Developmental Intestinal Regulator ELT-2 Controls p38-Dependent Immune Responses in Adult C. elegans

    OpenAIRE

    Block, Dena H. S.; Kwame Twumasi-Boateng; Hae Sung Kang; Jolie A Carlisle; Alexandru Hanganu; Ty Yu-Jen Lai; Michael Shapira

    2015-01-01

    Author Summary C. elegans provides a tractable genetic model to study the regulation of the evolutionarily conserved innate immune system. One of the central signaling modules of innate immunity in all organisms is the p38 pathway, which has been studied extensively in C. elegans. Such studies identified the transcription factors ATF-7 and SKN-1 as proteins mediating downstream effects of the p38 pathway on immune and oxidative stress gene expression. Previous studies in C. elegans also ident...

  18. Consideraciones sobre la identidad de Onychochaeta elegans (Cognetti, 1905 (Oligochaeta, Glossoscolecidae

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    Rodríguez, C.

    2003-06-01

    Full Text Available Considerations on the identity of Onychochaeta elegans (Cognetti, 1905 (Oligochaeta, Glossoscolecidae Anatomical variability of Onychochaeta elegans in Cuban populations was studied. A comparison among these populations and O. elegans cubana Michaelsen, 1924 and O. cubana Zicsi, 1995 from Cuba, as well as the descriptions of the typical form of Cognetti (1905 from Panama and Colombian specimens (Righi, 1995 was made. Besides, new materials from Mexico and Panama were added. Variations in anatomical characters in Cuban populations included those present in continental forms, so, there were not any character that justifies the division of O. elegans nor subspecies neither in distinct insular and continental species.

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

    Science.gov (United States)

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

    2016-01-01

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

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

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    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.

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

    Science.gov (United States)

    Ulrich, Xialing

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

  2. 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

  3. Notes on Hydroides elegans (Haswell, 1883) and Mercierella enigmatica Fauvel, 1923, alien serpulid Polychaetes introduced into the Netherlands

    NARCIS (Netherlands)

    Hove, ten Harry A.

    1974-01-01

    The occurrence of Hydroides elegans in Dutch waters is observed for the first time. Differences with H. norvegica are discussed. Possible ways of introduction of H. elegans and Mercierella enigmatica are discussed.

  4. Running worms: C. elegans self-sorting by electrotaxis.

    Directory of Open Access Journals (Sweden)

    Xavier Manière

    Full Text Available The nematode C. elegans displays complex dynamical behaviors that are commonly used to identify relevant phenotypes. Although its maintenance is straightforward, sorting large populations of worms when looking for a behavioral phenotype is difficult, time consuming and hardly quantitative when done manually. Interestingly, when submitted to a moderate electric field, worms move steadily along straight trajectories. Here, we report an inexpensive method to measure worms crawling velocities and sort them within a few minutes by taking advantage of their electrotactic skills. This method allows to quantitatively measure the effect of mutations and aging on worm's crawling velocity. We also show that worms with different locomotory phenotypes can be spatially sorted, fast worms traveling away from slow ones. Group of nematodes with comparable locomotory fitness could then be isolated for further analysis. C. elegans is a growing model for neurodegenerative diseases and using electrotaxis for self-sorting can improve the high-throughput search of therapeutic bio-molecules.

  5. Dietary and microbiome factors determine longevity in Caenorhabditis elegans

    Science.gov (United States)

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

    2016-01-01

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

  6. Endogenous RNAi and adaptation to environment in C. elegans

    Science.gov (United States)

    Grishok, Alla

    2012-01-01

    The contributions of short RNAs to the control of repetitive elements are well documented in animals and plants. Here, the role of endogenous RNAi and AF10 homolog ZFP-1 in the adaptation of C. elegans to the environment is discussed. First, modulation of insulin signaling through regulation of transcription of the PDK-1 kinase (Mansisidor et al., PLoS Genetics, 2011) is reviewed. Second, an siRNA-based natural selection model is proposed in which variation in endogenous siRNA pools between individuals is subject to natural selection similarly to DNA-based genetic variation. The value of C. elegans for the research of siRNA-based epigenetic variation and adaptation is highlighted. PMID:24058837

  7. Undulatory locomotion of {\\it C. elegans} on wet surfaces

    CERN Document Server

    Shen, Xiao N; Krajacic, P; Lamitina, T; Arratia, P E

    2011-01-01

    The physical and bio-mechanical principles that govern undulatory movement on wet surfaces have important applications in physiology, physics, and engineering. The nematode {\\it C. 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 {\\it 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. We find that the normal and tangential surface drag force coefficients during crawling are approximately 220 and 22, respectively, and the drag coefficient ratio is approximately 10. During crawling, the calculated internal bending force is time-periodic and spatially complex, ...

  8. Salvia elegans: uma fonte natural de compostos antioxidantes

    OpenAIRE

    Pereira, Olívia R.; Afonso, Andrea F.; Silva, Joana A.; Batista, Ana Rita; Sobral, Abílio J.F.N.; Susana M Cardoso

    2014-01-01

    A espécie Salvia elegans é um arbusto que pertence ao género Salvia, família das Lamiaceae. Várias espécies do mesmo género têm vindo a ser cultivadas para uso na culinária e em medicina tradicional [1]. Devido ao seu cheiro característico, a S. elegans é vulgarmente conhecida por salva ananás e utilizada como condimento ou aromatizante em alimentos. No México esta espécie é popularmente conhecida como “mirto” e tem sido usada na medicina tradicional para tratar afeções do sistema nervoso cen...

  9. C. elegans as a model for membrane traffic.

    Science.gov (United States)

    Sato, Ken; Norris, Anne; Sato, Miyuki; Grant, Barth D

    2014-01-01

    The counterbalancing action of the endocytosis and secretory pathways maintains a dynamic equilibrium that regulates the composition of the plasma membrane, allowing it to maintain homeostasis and to change rapidly in response to alterations in the extracellular environment and/or intracellular metabolism. These pathways are intimately integrated with intercellular signaling systems and play critical roles in all cells. Studies in Caenorhabditis elegans have revealed diverse roles of membrane trafficking in physiology and development and have also provided molecular insight into the fundamental mechanisms that direct cargo sorting, vesicle budding, and membrane fisson and fusion. In this review, we summarize progress in understanding membrane trafficking mechanisms derived from work in C. elegans, focusing mainly on work done in non-neuronal cell-types, especially the germline, early embryo, coelomocytes, and intestine.

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

    Science.gov (United States)

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

    2015-11-13

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

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

    Science.gov (United States)

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

    2016-12-19

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

  12. Pharmacognostic Standardization Parameters of Roylea elegans Wall (Aerial Parts

    Directory of Open Access Journals (Sweden)

    Neeru

    2016-05-01

    Full Text Available To evaluate the pharmacognostical study of Roylea elegans (aerial parts. The qualitative and quantitative microscopy, physicochemical evaluation, phytochemical screening and fluorescence analysis of the plant were done by the standard procedure recommended in the WHO guidelines. Macroscopic study shows that leaves were dark green with lemon like odor and bitter taste, 2-8 cm length and 1-8 cm wide, shape: ovate, hairy upper and lower surface, apex: acute and having reticulate veination, Stems: were light green Microscopic evaluation of the leaves powder shows the presence of trichomes (unicellular covering and glandular, upper epidermis, vessels, xylem fibres, wavy trichomes. The transverse section of the leaf shows the presence of epidermis layer followed by cuticle layer, lignified vascular bundles, trichomes, collenchyma, and palisade cells. Various pharmacognostical parameters help to evaluate the identification and standardization of Roylea elegans (aerial part.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-11-01

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

  14. Magnetosensitive neurons mediate geomagnetic orientation in Caenorhabditis elegans.

    Science.gov (United States)

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

    2015-06-17

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

  15. Chaperone-interacting TPR proteins in Caenorhabditis elegans.

    Science.gov (United States)

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

    2013-08-23

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

  16. A soil bioassay using the nematode Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  17. Visualization of C. elegans transgenic arrays by GFP

    OpenAIRE

    Sternberg Paul W; Gonzalez-Serricchio Aidyl S

    2006-01-01

    Abstract Background Targeting the green fluorescent protein (GFP) via the E. coli lac repressor (LacI) to a specific DNA sequence, the lac operator (lacO), allows visualization of chromosomes in yeast and mammalian cells. In principle this method of visualization could be used for genetic mosaic analysis, which requires cell-autonomous markers that can be scored easily and at single cell resolution. The C. elegans lin-3 gene encodes an epidermal growth factor family (EGF) growth factor. lin-3...

  18. A mutational analysis of Caenorhabditis elegans in space

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-10

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

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

    Directory of Open Access Journals (Sweden)

    Gunnar Rätsch

    2007-02-01

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

  20. Spaceflight and ageing: reflecting on Caenorhabditis elegans in space.

    Science.gov (United States)

    Honda, Yoko; Honda, Shuji; Narici, Marco; Szewczyk, Nathaniel J

    2014-01-01

    The prospect of space travel continues to capture the imagination. Several competing companies are now promising flights for the general population. Previously, it was recognized that many of the physiological changes that occur with spaceflight are similar to those seen with normal ageing. This led to the notion that spaceflight can be used as a model of accelerated ageing and raised concerns about the safety of individuals engaging in space travel. Paradoxically, however, space travel has been recently shown to be beneficial to some aspects of muscle health in the tiny worm Caenorhabditis elegans. C. elegans is a commonly used laboratory animal for studying ageing. C. elegans displays age-related decline of some biological processes observed in ageing humans, and about 35% of C. elegans' genes have human homologs. Space flown worms were found to have decreased expression of a number of genes that increase lifespan when expressed at lower levels. These changes were accompanied by decreased accumulation of toxic protein aggregates in ageing worms' muscles. Thus, in addition to spaceflight producing physiological changes that are similar to accelerated ageing, it also appears to produce some changes similar to delayed ageing. Here, we put forward the hypothesis that in addition to the previously well-appreciated mechanotransduction changes, neural and endocrine signals are altered in response to spaceflight and that these may have both negative (e.g. less muscle protein) and some positive consequences (e.g. healthier muscles), at least for invertebrates, with respect to health in space. Given that changes in circulating hormones are well documented with age and in astronauts, our view is that further research into the relationship between metabolic control, ageing, and adaptation to the environment should be productive in advancing our understanding of the physiology of both spaceflight and ageing.

  1. Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning

    OpenAIRE

    Gallagher, Larry A.; Manoil, Colin

    2001-01-01

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

  2. Dietary Supplementation of Polyunsaturated Fatty Acids in Caenorhabditis elegans

    OpenAIRE

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

    2013-01-01

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

  3. Glia Are Essential for Sensory Organ Function in C. elegans

    OpenAIRE

    Bacaj, Taulant; Tevlin, Maya; Lu, Yun; Shaham, Shai

    2008-01-01

    Sensory organs are composed of neurons, which convert environmental stimuli to electrical signals, and glia-like cells, whose functions are not well-understood. To decipher glial roles in sensory organs, we ablated the sheath glial cell of the major sensory organ of Caenorhabditis elegans. We found that glia-ablated animals exhibit profound sensory deficits and that glia provide activities that affect neuronal morphology, behavior generation, and neuronal uptake of lipophilic dyes. To underst...

  4. Targeted gene deletions in C. elegans using transposon excision

    Science.gov (United States)

    Frøkjær-Jensen, Christian; Davis, M. Wayne; Hollopeter, Gunther; Taylor, Jon; Harris, Todd; Nix, Paola; Lofgren, Rachel; Prestgard-Duke, Michael; Bastiani, Michael; Moerman, Donald G.; Jorgensen, Erik M.

    2010-01-01

    We have developed a method, MosDel, to generate targeted knock-outs of genes in C. elegans. We make use of the Mos1 transposase to excise a Mos1 transposon adjacent to the region to be deleted. The double-strand break is repaired using injected DNA as a template. Repair can delete up to 25 kb of DNA and simultaneously insert a positive selection marker. PMID:20418868

  5. Serotonin regulates repolarization of the C. elegans pharyngeal muscle

    OpenAIRE

    Niacaris, Timothy; Avery, Leon

    2003-01-01

    Caenorhabditis elegans feeds by rhythmically contracting its pharynx to ingest bacteria. The rate of pharyngeal contraction is increased by serotonin and suppressed by octopamine. Using an electrophysiological assay, we show that serotonin and octopamine regulate two additional aspects of pharyngeal behavior. Serotonin decreases the duration of the pharyngeal action potential and enhances activity of the pharyngeal M3 motor neurons. Gramine, a competitive serotonin antagonist, and octopamine ...

  6. Programmed cell death in C. elegans, mammals and plants.

    Science.gov (United States)

    Lord, Christina E N; Gunawardena, Arunika H L A N

    2012-08-01

    Programmed cell death (PCD) is the regulated removal of cells within an organism and plays a fundamental role in growth and development in nearly all eukaryotes. In animals, the model organism Caenorhabditis elegans (C. elegans) has aided in elucidating many of the pathways involved in the cell death process. Various analogous PCD processes can also be found within mammalian PCD systems, including vertebrate limb development. Plants and animals also appear to share hallmarks of PCD, both on the cellular and molecular level. Cellular events visualized during plant PCD resemble those seen in animals including: nuclear condensation, DNA fragmentation, cytoplasmic condensation, and plasma membrane shrinkage. Recently the molecular mechanisms involved in plant PCD have begun to be elucidated. Although few regulatory proteins have been identified as conserved across all eukaryotes, molecular features such as the participation of caspase-like proteases, Bcl-2-like family members and mitochondrial proteins appear to be conserved between plant and animal systems. Transgenic expression of mammalian and C. elegans pro- and anti-apoptotic genes in plants has been observed to dramatically influence the regulatory pathways of plant PCD. Although these genes often show little to no sequence similarity they can frequently act as functional substitutes for one another, thus suggesting that action may be more important than sequence resemblance. Here we present a summary of these findings, focusing on the similarities, between mammals, C. elegans, and plants. An emphasis will be placed on the mitochondria and its role in the cell death pathway within each organism. Through the comparison of these systems on both a cellular and molecular level we can begin to better understand PCD in plant systems, and perhaps shed light on the pathways, which are controlling the process. This manuscript adds to the field of PCD in plant systems by profiling apoptotic factors, to scale on a protein

  7. Antifungal chemical compounds identified using a C. elegans pathogenicity assay.

    Directory of Open Access Journals (Sweden)

    Julia Breger

    2007-02-01

    Full Text Available There is an urgent need for the development of new antifungal agents. A facile in vivo model that evaluates libraries of chemical compounds could solve some of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida species, are ingested by Caenorhabditis elegans and establish a persistent lethal infection in the C. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament formation, are also involved in nematode killing. We devised a Candida-mediated C. elegans assay that allows high-throughput in vivo screening of chemical libraries for antifungal activities, while synchronously screening against toxic compounds. The assay is performed in liquid media using standard 96-well plate technology and allows the study of C. albicans in non-planktonic form. A screen of 1,266 compounds with known pharmaceutical activities identified 15 (approximately 1.2% that prolonged survival of C. albicans-infected nematodes and inhibited in vivo filamentation of C. albicans. Two compounds identified in the screen, caffeic acid phenethyl ester, a major active component of honeybee propolis, and the fluoroquinolone agent enoxacin exhibited antifungal activity in a murine model of candidiasis. The whole-animal C. elegans assay may help to study the molecular basis of C. albicans pathogenesis and identify antifungal compounds that most likely would not be identified by in vitro screens that target fungal growth. Compounds identified in the screen that affect the virulence of Candida in vivo can potentially be used as "probe compounds" and may have antifungal activity against other fungi.

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

    Directory of Open Access Journals (Sweden)

    Surasri N Sahu

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

  9. In vivo neuronal calcium imaging in C. elegans.

    Science.gov (United States)

    Chung, Samuel H; Sun, Lin; Gabel, Christopher V

    2013-04-10

    The nematode worm C. elegans is an ideal model organism for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, well-characterized nervous system allows identification and fluorescence imaging of any neuron within the intact animal. Simple immobilization techniques with minimal impact on the animal's physiology allow extended time-lapse imaging. The development of genetically-encoded calcium sensitive fluorophores such as cameleon and GCaMP allow in vivo imaging of neuronal calcium relating both cell physiology and neuronal activity. Numerous transgenic strains expressing these fluorophores in specific neurons are readily available or can be constructed using well-established techniques. Here, we describe detailed procedures for measuring calcium dynamics within a single neuron in vivo using both GCaMP and cameleon. We discuss advantages and disadvantages of both as well as various methods of sample preparation (animal immobilization) and image analysis. Finally, we present results from two experiments: 1) Using GCaMP to measure the sensory response of a specific neuron to an external electrical field and 2) Using cameleon to measure the physiological calcium response of a neuron to traumatic laser damage. Calcium imaging techniques such as these are used extensively in C. elegans and have been extended to measurements in freely moving animals, multiple neurons simultaneously and comparison across genetic backgrounds. C. elegans presents a robust and flexible system for in vivo neuronal imaging with advantages over other model systems in technical simplicity and cost.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Nicole Shangming Hou

    2012-05-01

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

  12. 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.

  13. Goalpha regulates volatile anesthetic action in Caenorhabditis elegans.

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

    2001-06-01

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

  14. Searching WormBase for information about Caenorhabditis elegans.

    Science.gov (United States)

    Schwarz, Erich M; Sternberg, Paul W

    2006-07-01

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

  15. Cell-specific proteomic analysis in Caenorhabditis elegans.

    Science.gov (United States)

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

    2015-03-03

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

  16. Pan-neuronal imaging in roaming Caenorhabditis elegans.

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

    2016-02-23

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

  17. Subcomplex Ilambda specifically controls integrated mitochondrial functions in Caenorhabditis elegans.

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    Marni J Falk

    Full Text Available Complex I dysfunction is a common, heterogeneous cause of human mitochondrial disease having poorly understood pathogenesis. The extensive conservation of complex I composition between humans and Caenorhabditis elegans permits analysis of individual subunit contribution to mitochondrial functions at both the whole animal and mitochondrial levels. We provide the first experimentally-verified compilation of complex I composition in C. elegans, demonstrating 84% conservation with human complex I. Individual subunit contribution to mitochondrial respiratory capacity, holocomplex I assembly, and animal anesthetic behavior was studied in C. elegans by RNA interference-generated knockdown of nuclear genes encoding 28 complex I structural subunits and 2 assembly factors. Not all complex I subunits directly impact respiratory capacity. Subcomplex Ilambda subunits along the electron transfer pathway specifically control whole animal anesthetic sensitivity and complex II upregulation, proportionate to their relative impairment of complex I-dependent oxidative capacity. Translational analysis of complex I dysfunction facilitates mechanistic understanding of individual gene contribution to mitochondrial disease. We demonstrate that functional consequences of complex I deficiency vary with the particular subunit that is defective.

  18. Antidepressant and anxiolytic effects of hydroalcoholic extract from Salvia elegans.

    Science.gov (United States)

    Herrera-Ruiz, Maribel; García-Beltrán, Yolanda; Mora, Sergio; Díaz-Véliz, Gabriela; Viana, Glauce S B; Tortoriello, Jaime; Ramírez, Guillermo

    2006-08-11

    Salvia elegans Vahl (Lamiaceae), popularly known as "mirto", is a shrub that has been widely used in Mexican traditional medicine for the treatment of different central nervous system (CNS) diseases, principally, anxiety. Nevertheless, the available scientific information about this species is scarce and there are no reports related to its possible effect on the CNS. In this work, the antidepressant and anxiolytic like effects of hydroalcoholic (60%) extract of Salvia elegans (leaves and flowers) were evaluated in mice. The extract, administered orally, was able to increase the percentage of time spent and the percentage of arm entries in the open arms of the elevated plus-maze, as well as to increase the time spent by mice in the illuminated side of the light-dark test, and to decrease the immobility time of mice subjected to the forced swimming test. The same extract was not able to modify the spontaneous locomotor activity measured in the open field test. These results provide support for the potential antidepressant and anxiolytic activity of Salvia elegans.

  19. Direct micro-mechanical measurements on C. elegans

    Science.gov (United States)

    Backholm, Matilda; Ryu, William S.; Dalnoki-Veress, Kari

    2013-03-01

    The millimeter-sized nematode Caenorhabditis elegans provides an excellent biophysical system for both static and dynamic biomechanical studies. The undulatory motion exhibited by this model organism as it crawls or swims through a medium is ubiquitous in nature at scales from microns to meters. A successful description of this form of locomotion requires knowledge of the material properties of the crawler, as well as its force output as it moves. Here we present an experimental technique with which the material properties and dynamics of C. elegans can be directly probed. By using the deflection of a flexible micropipette, the bending stiffness of C. elegans has been measured at all stages of its life cycle, as well as along the body of the adult worm. The mechanical properties of the worm are modelled as a viscoelastic material which provides new insights into its material properties. The forces exerted by the worm during undulatory motion are also discussed. Direct experimental characterization of this model organism provides guidance for theoretical treatments of undulatory locomotion in general.

  20. The Redox System in C. elegans, a Phylogenetic Approach

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    Andrew D. Johnston

    2012-01-01

    Full Text Available Oxidative stress is a toxic state caused by an imbalance between the production and elimination of reactive oxygen species (ROS. ROS cause oxidative damage to cellular components such as proteins, lipids, and nucleic acids. While the role of ROS in cellular damage is frequently all that is noted, ROS are also important in redox signalling. The “Redox Hypothesis" has been proposed to emphasize a dual role of ROS. This hypothesis suggests that the primary effect of changes to the redox state is modified cellular signalling rather than simply oxidative damage. In extreme cases, alteration of redox signalling can contribute to the toxicity of ROS, as well as to ageing and age-related diseases. The nematode species Caenorhabditis elegans provides an excellent model for the study of oxidative stress and redox signalling in animals. We use protein sequences from central redox systems in Homo sapiens, Drosophila melanogaster, and Saccharomyces cerevisiae to query Genbank for homologous proteins in C. elegans. We then use maximum likelihood phylogenetic analysis to compare protein families between C. elegans and the other organisms to facilitate future research into the genetics of redox biology.

  1. An Aversive Response to Osmotic Upshift in Caenorhabditis elegans.

    Science.gov (United States)

    Yu, Jingyi; Yang, Wenxing; Liu, He; Hao, Yingsong; Zhang, Yun

    2017-01-01

    Environmental osmolarity presents a common type of sensory stimulus to animals. While behavioral responses to osmotic changes are important for maintaining a stable intracellular osmolarity, the underlying mechanisms are not fully understood. In the natural habitat of Caenorhabditis elegans, changes in environmental osmolarity are commonplace. It is known that the nematode acutely avoids shocks of extremely high osmolarity. Here, we show that C. elegans also generates gradually increased aversion of mild upshifts in environmental osmolarity. Different from an acute avoidance of osmotic shocks that depends on the function of a transient receptor potential vanilloid channel, the slow aversion to osmotic upshifts requires the cGMP-gated sensory channel subunit TAX-2. TAX-2 acts in several sensory neurons that are exposed to body fluid to generate the aversive response through a motor network that underlies navigation. Osmotic upshifts activate the body cavity sensory neuron URX, which is known to induce aversion upon activation. Together, our results characterize the molecular and cellular mechanisms underlying a novel sensorimotor response to osmotic stimuli and reveal that C. elegans engages different behaviors and the underlying mechanisms to regulate responses to extracellular osmolarity.

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

    Science.gov (United States)

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

    2010-01-01

    To navigate different environments, an animal must be able to adapt its locomotory gait to its physical surroundings. The nematode Caenorhabditis elegans, between swimming in water and crawling on surfaces, adapts its locomotory gait to surroundings that impose approximately 10,000-fold differences in mechanical resistance. Here we investigate this feat by studying the undulatory movements of C. elegans in Newtonian fluids spanning nearly five orders of magnitude in viscosity. In these fluids, the worm undulatory gait varies continuously with changes in external load: As load increases, both wavelength and frequency of undulation decrease. We also quantify the internal viscoelastic properties of the worm’s body and their role in locomotory dynamics. We incorporate muscle activity, internal load, and external load into a biomechanical model of locomotion and show that (i) muscle power is nearly constant across changes in locomotory gait, and (ii) the onset of gait adaptation occurs as external load becomes comparable to internal load. During the swimming gait, which is evoked by small external loads, muscle power is primarily devoted to bending the worm’s elastic body. During the crawling gait, evoked by large external loads, comparable muscle power is used to drive the external load and the elastic body. Our results suggest that C. elegans locomotory gait continuously adapts to external mechanical load in order to maintain propulsive thrust. PMID:21048086

  3. Undulatory locomotion of Caenorhabditis elegans on wet surfaces.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2010-11-23

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

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

    Science.gov (United States)

    Hou, Nicole Shangming; Taubert, Stefan

    2012-01-01

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

  6. Caenorhabditis elegans is a useful model for anthelmintic discovery

    Science.gov (United States)

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

    2015-01-01

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

  7. Introduction to germ cell development in Caenorhabditis elegans.

    Science.gov (United States)

    Pazdernik, Nanette; Schedl, Tim

    2013-01-01

    A central feature of the continuum of life in sexually reproducing metazoans is the cycle of the germline from one generation to the next. This volume describes the cycle of the germline for Caenorhabditis elegans through chapters that are focused on distinct aspects or processes in germ cell development. Topics include sequential and dependent processes such as specification of germ cells as distinct from somatic cells, sex determination, stem cell proliferative fate versus meiotic development decision, recombination/progression through meiotic prophase, contemporaneous processes such as gametogenesis, meiotic development and apoptosis, and continuing the cycle into the next generation through fertilization and the oocyte-to-embryo transition. Throughout germ cell development, translational control and epigenetic mechanisms play prominent roles. These different aspects of germ cell development are seamlessly integrated under optimal conditions and are modified in the different reproductive strategies that are employed by C. elegans under harsh environmental conditions. In this chapter, we set the stage by providing a brief background on the C. elegans system and germ cell development, indicating processes in the cycle of the germline that are covered in each chapter.

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

    Science.gov (United States)

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

    2014-11-19

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

  9. A gene expression fingerprint of C. elegans embryonic motor neurons

    Directory of Open Access Journals (Sweden)

    Dupuy Denis

    2005-03-01

    Full Text Available Abstract Background Differential gene expression specifies the highly diverse cell types that constitute the nervous system. With its sequenced genome and simple, well-defined neuroanatomy, the nematode C. elegans is a useful model system in which to correlate gene expression with neuron identity. The UNC-4 transcription factor is expressed in thirteen embryonic motor neurons where it specifies axonal morphology and synaptic function. These cells can be marked with an unc-4::GFP reporter transgene. Here we describe a powerful strategy, Micro-Array Profiling of C. elegans cells (MAPCeL, and confirm that this approach provides a comprehensive gene expression profile of unc-4::GFP motor neurons in vivo. Results Fluorescence Activated Cell Sorting (FACS was used to isolate unc-4::GFP neurons from primary cultures of C. elegans embryonic cells. Microarray experiments detected 6,217 unique transcripts of which ~1,000 are enriched in unc-4::GFP neurons relative to the average nematode embryonic cell. The reliability of these data was validated by the detection of known cell-specific transcripts and by expression in UNC-4 motor neurons of GFP reporters derived from the enriched data set. In addition to genes involved in neurotransmitter packaging and release, the microarray data include transcripts for receptors to a remarkably wide variety of signaling molecules. The added presence of a robust array of G-protein pathway components is indicative of complex and highly integrated mechanisms for modulating motor neuron activity. Over half of the enriched genes (537 have human homologs, a finding that could reflect substantial overlap with the gene expression repertoire of mammalian motor neurons. Conclusion We have described a microarray-based method, MAPCeL, for profiling gene expression in specific C. elegans motor neurons and provide evidence that this approach can reveal candidate genes for key roles in the differentiation and function of these cells

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  11. The C. elegans Crumbs family contains a CRB3 homolog and is not essential for viability.

    NARCIS (Netherlands)

    Waaijers, S.; Ramalho, J.J.; Koorman, T.; Kruse, E.; Boxem, M.

    2015-01-01

    Crumbs proteins are important regulators of epithelial polarity. In C. elegans, no essential role for the two described Crumbs homologs has been uncovered. Here, we identify and characterize an additional Crumbs family member in C. elegans, which we termed CRB-3 based on its similarity in size and s

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

    Science.gov (United States)

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

    2001-01-01

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

  13. In vivo visualization and quantification of mitochondrial morphology in C. elegans

    NARCIS (Netherlands)

    Smith, R.L.; De Vos, W.H.; de Boer, R.; Manders, E.M.M.; van der Spek, H.; Weissig, V.; Edeas, M.

    2015-01-01

    Caenorhabditis elegans is a highly malleable model system, intensively used for functional, genetic, cytometric, and integrative studies. Due to its simplicity and large muscle cell number, C. elegans has frequently been used to study mitochondrial deficiencies caused by disease or drug toxicity. He

  14. On-Demand Isolation and Manipulation of C. elegans by In Vitro Maskless Photopatterning.

    Directory of Open Access Journals (Sweden)

    C Ryan Oliver

    Full Text Available Caenorhabditis elegans (C. elegans is a model organism for understanding aging and studying animal behavior. Microfluidic assay techniques have brought widespread advances in C. elegans research; however, traditional microfluidic assays such as those based on soft lithography require time-consuming design and fabrication cycles and offer limited flexibility in changing the geometric environment during experimentation. We present a technique for maskless photopatterning of a biocompatible hydrogel on an NGM (Agar substrate, enabling dynamic manipulation of the C. elegans culture environment in vitro. Maskless photopatterning is performed using a projector-based microscope system largely built from off-the-shelf components. We demonstrate the capabilities of this technique by building micropillar arrays during C. elegans observation, by fabricating free-floating mechanisms that can be actuated by C. elegans motion, by using freehand drawing to isolate individual C. elegans in real time, and by patterning arrays of mazes for isolation and fitness testing of C. elegans populations. In vitro photopatterning enables rapid and flexible design of experiment geometry as well as real-time interaction between the researcher and the assay such as by sequential isolation of individual organisms. Future adoption of image analysis and machine learning techniques could be used to acquire large datasets and automatically adapt the assay geometry.

  15. The C. elegans Crumbs family contains a CRB3 homolog and is not essential for viability.

    NARCIS (Netherlands)

    Waaijers, S.; Ramalho, J.J.; Koorman, T.; Kruse, E.; Boxem, M.

    2015-01-01

    Crumbs proteins are important regulators of epithelial polarity. In C. elegans, no essential role for the two described Crumbs homologs has been uncovered. Here, we identify and characterize an additional Crumbs family member in C. elegans, which we termed CRB-3 based on its similarity in size and s

  16. 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…

  17. NHS Mediated CdTe Quantum Dots/Albumin Conjugates and Labeling C. Elegans

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Luminescent quantum dots(QDs) are a promising alternative to organic dyes for biomedical assays and imaging.A new conjugation method, NHS mediated conjugating, for QDs and BSA was introduced. The QDs-BSA conjugates were confirmed, and their stability has been proved. Caenorhabditis elegans (C. elegans) were used as animal models, and the imaging of QDs in the organism was studied.

  18. 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…

  19. 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…

  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. Using RNAi in C. "elegans" to Demonstrate Gene Knockdown Phenotypes in the Undergraduate Biology Lab Setting

    Science.gov (United States)

    Roy, Nicole M.

    2013-01-01

    RNA interference (RNAi) is a powerful technology used to knock down genes in basic research and medicine. In 2006 RNAi technology using "Caenorhabditis elegans" ("C. elegans") was awarded the Nobel Prize in medicine and thus students graduating in the biological sciences should have experience with this technology. However,…

  2. 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 ...

  3. In vivo visualization and quantification of mitochondrial morphology in C. elegans

    NARCIS (Netherlands)

    Smith, R.L.; De Vos, W.H.; de Boer, R.; Manders, E.M.M.; van der Spek, H.; Weissig, V.; Edeas, M.

    2015-01-01

    Caenorhabditis elegans is a highly malleable model system, intensively used for functional, genetic, cytometric, and integrative studies. Due to its simplicity and large muscle cell number, C. elegans has frequently been used to study mitochondrial deficiencies caused by disease or drug toxicity.

  4. Genetic control of left/right asymmetry in C. elegans neuroblast migration

    NARCIS (Netherlands)

    Middelkoop, T.C.

    2014-01-01

    The migration of cells is crucial for proper animal development. In order to study cell migration in an in vivo context we used the small nematode C. elegans as a model organism. During C. elegans larval development two Q neuroblasts, initially positioned on equivalent left/right positions, migrate

  5. Influence of Silicon on Resistance of Zinnia Elegans to Myzus Persicae (Hemiptera: Aphididae)

    Science.gov (United States)

    Studies were conducted to examine the effect of treating Zinnia elegans Jacq. with soluble silicon on the performance of the green peach aphid, Myzus persicae (Sulzer). Zinnia elegans plants were irrigated every 2 days throughout the duration of the experiment with a nutrient solution amended with ...

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

    Science.gov (United States)

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

  7. Apophysomyces elegans: epidemiology, amplified fragment length polymorphism typing, and in vitro antifungal susceptibility pattern.

    NARCIS (Netherlands)

    Chakrabarti, A.; Shivaprakash, M.R.; Curfs-Breuker, I.; Baghela, A.; Klaassen, C.H.; Meis, J.F.G.M.

    2010-01-01

    Apophysomyces elegans is an emerging pathogen in India. We planned the present study to analyze the clinical pattern of the disease, to perform molecular strain typing, and to determine the in vitro activities of eight antifungal drugs against A. elegans. A total of 16 clinical and two environmental

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

    Directory of Open Access Journals (Sweden)

    Sabine P Schrimpf

    2009-03-01

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

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

    Science.gov (United States)

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

    2006-04-01

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

  10. A microfluidic device for the continuous culture and analysis of Caenorhabditis elegans in a toxic aqueous environment

    Science.gov (United States)

    Jung, Jaehoon; Nakajima, Masahiro; Tajima, Hirotaka; Huang, Qiang; Fukuda, Toshio

    2013-08-01

    The nematode Caenorhabditis elegans (C. elegans) receives attention as a bioindicator, and the C. elegans condition has been recently analyzed using microfluidic devices equipped with an imaging system. To establish a method without an imaging system, we have proposed a novel microfluidic device with which to analyze the condition of C. elegans from the capacitance change using a pair of micro-electrodes. The device was designed to culture C. elegans, to expose C. elegans to an external stimulus, such as a chemical or toxicant, and to measure the capacitance change which indicates the condition of C. elegans. In this study, to demonstrate the capability of our device in a toxic aqueous environment, the device was applied to examine the effect of cadmium on C. elegans. Thirty L4 larval stage C. elegans were divided into three groups. One group was a control group and the other groups were exposed to cadmium solutions with concentrations of 5% and 10% LC50 for 24 h. The capacitance change and the body volume of C. elegans as a reference were measured four times and we confirmed the correlation between them. It shows that our device can analyze the condition of C. elegans without an imaging system.

  11. C. elegans SMA-10 regulates BMP receptor trafficking.

    Science.gov (United States)

    Gleason, Ryan J; Vora, Mehul; Li, Ying; Kane, Nanci S; Liao, Kelvin; Padgett, Richard W

    2017-01-01

    Signal transduction of the conserved transforming growth factor-β (TGFβ) family signaling pathway functions through two distinct serine/threonine transmembrane receptors, the type I and type II receptors. Endocytosis orchestrates the assembly of signaling complexes by coordinating the entry of receptors with their downstream signaling mediators. Recently, we showed that the C. elegans type I bone morphogenetic protein (BMP) receptor SMA-6, part of the TGFβ family, is recycled through the retromer complex while the type II receptor, DAF-4 is recycled in a retromer-independent, ARF-6 dependent manner. From genetic screens in C. elegans aimed at identifying new modifiers of BMP signaling, we reported on SMA-10, a conserved LRIG (leucine-rich and immunoglobulin-like domains) transmembrane protein. It is a positive regulator of BMP signaling that binds to the SMA-6 receptor. Here we show that the loss of sma-10 leads to aberrant endocytic trafficking of SMA-6, resulting in its accumulation in distinct intracellular endosomes including the early endosome, multivesicular bodies (MVB), and the late endosome with a reduction in signaling strength. Our studies show that trafficking defects caused by the loss of sma-10 are not universal, but affect only a limited set of receptors. Likewise, in Drosophila, we find that the fly homolog of sma-10, lambik (lbk), reduces signaling strength of the BMP pathway, consistent with its function in C. elegans and suggesting evolutionary conservation of function. Loss of sma-10 results in reduced ubiquitination of the type I receptor SMA-6, suggesting a possible mechanism for its regulation of BMP signaling.

  12. Drug absorption efficiency in Caenorhbditis elegans delivered by different methods.

    Directory of Open Access Journals (Sweden)

    Shan-Qing Zheng

    Full Text Available BACKGROUND: Caenorhbditis elegans has being vigorously used as a model organism in many research fields and often accompanied by administrating with various drugs. The methods of delivering drugs to worms are varied from one study to another, which make difficult in comparing results between studies. METHODOLOGY/PRINCIPAL FINDINGS: We evaluated the drug absorption efficiency in C. elegans using five frequently used methods with resveratrol with low aqueous solubility and water-soluble 5-Fluoro-2'-deoxyuridine (FUDR as positive compounds. The drugs were either applied to the LB medium with bacteria OP50, before spreading onto Nematode Growth Medium (NGM plates (LB medium method, or to the NGM with live (NGM live method or dead bacteria (NGM dead method, or spotting the drug solution to the surface of plates directly (spot dead method, or growing the worms in liquid medium (liquid growing method. The concentration of resveratrol and FUDR increased gradually within C. elegans and reached the highest during 12 hours to one day and then decreased slowly. At the same time point, the higher the drug concentration, the higher the metabolism rate. The drug concentrations in worms fed with dead bacteria were higher than with live bacteria at the same time point. Consistently, the drug concentration in medium with live bacteria decreased much faster than in medium with dead bacteria, reach to about half of the original concentration within 12 hours. CONCLUSION: Resveratrol with low aqueous solubility and water-soluble FUDR have the same absorption and metabolism pattern. The drug metabolism rate in worms was both dosage and time dependent. NGM dead method and liquid growing method achieved the best absorption efficiency in worms. The drug concentration within worms was comparable with that in mice, providing a bridge for dose translation from worms to mammals.

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

    Science.gov (United States)

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

    2013-02-01

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

  14. 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.

  15. Structural properties of the Caenorhabditis elegans neuronal network.

    Science.gov (United States)

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

    2011-02-03

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

  16. Structural properties of the Caenorhabditis elegans neuronal network.

    Directory of Open Access Journals (Sweden)

    Lav R Varshney

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

  17. Polyamine-independent Expression of Caenorhabditis elegans Antizyme.

    Science.gov (United States)

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

    2015-07-17

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

  18. Optical silencing of C. elegans cells with arch proton pump.

    Directory of Open Access Journals (Sweden)

    Ayako Okazaki

    Full Text Available BACKGROUND: Optogenetic techniques using light-driven ion channels or ion pumps for controlling excitable cells have greatly facilitated the investigation of nervous systems in vivo. A model organism, C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. METHODOLOGY/PRINCIPAL FINDINGS: We describe the application of archaerhodopsin-3 (Arch, a recently reported optical neuronal silencer, to C. elegans. Arch::GFP expressed either in all neurons or body wall muscles of the entire body by means of transgenes were localized, at least partially, to the cell membrane without adverse effects, and caused locomotory paralysis of worms when illuminated by green light (550 nm. Pan-neuronal expression of Arch endowed worms with quick and sustained responsiveness to such light. Worms reliably responded to repeated periods of illumination and non-illumination, and remained paralyzed under continuous illumination for 30 seconds. Worms expressing Arch in different subsets of motor neurons exhibited distinct defects in the locomotory behavior under green light: selective silencing of A-type motor neurons affected backward movement while silencing of B-type motor neurons affected forward movement more severely. Our experiments using a heat-shock-mediated induction system also indicate that Arch becomes fully functional only 12 hours after induction and remains functional for more than 24 hour. CONCLUSIONS/SGNIFICANCE: Arch can be used for silencing neurons and muscles, and may be a useful alternative to currently widely used halorhodopsin (NpHR in optogenetic studies of C. elegans.

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

    Science.gov (United States)

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

    2013-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Rafael P Vázquez-Manrique

    2008-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Rafael P Vázquez-Manrique

    2008-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Schoofs Liliane

    2010-02-01

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

  3. Cell lineage and cell death: Caenorhabditis elegans and cancer research.

    Science.gov (United States)

    Potts, Malia B; Cameron, Scott

    2011-01-01

    Cancer is a complex disease in which cells have circumvented normal restraints on tissue growth and have acquired complex abnormalities in their genomes, posing a considerable challenge to identifying the pathways and mechanisms that drive fundamental aspects of the malignant phenotype. Genetic analyses of the normal development of the nematode Caenorhabditis elegans have revealed evolutionarily conserved mechanisms through which individual cells establish their fates, and how they make and execute the decision to survive or undergo programmed cell death. The pathways identified through these studies have mammalian counterparts that are co-opted by malignant cells. Effective cancer drugs now target some of these pathways, and more are likely to be discovered.

  4. Intracellular Assessment of ATP Levels in Caenorhabditis elegans

    Science.gov (United States)

    Palikaras, Konstantinos; Tavernarakis, Nektarios

    2017-01-01

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

  5. Google matrix analysis of C.elegans neural network

    CERN Document Server

    Kandiah, Vivek

    2013-01-01

    We study the structural properties of the neural network of the C.elegans (worm) from a directed graph point of view. The Google matrix analysis is used to characterize the neuron connectivity structure and node classifications are discussed and compared with physiological properties of the cells. Our results are obtained by a proper definition of neural directed network and subsequent eigenvector analysis which recovers some results of previous studies. Our analysis highlights particular sets of important neurons constituting the core of the neural system. The applications of PageRank, CheiRank and ImpactRank to characterization of interdependency of neurons are discussed.

  6. Visualization of C. elegans transgenic arrays by GFP

    Directory of Open Access Journals (Sweden)

    Sternberg Paul W

    2006-06-01

    Full Text Available Abstract Background Targeting the green fluorescent protein (GFP via the E. coli lac repressor (LacI to a specific DNA sequence, the lac operator (lacO, allows visualization of chromosomes in yeast and mammalian cells. In principle this method of visualization could be used for genetic mosaic analysis, which requires cell-autonomous markers that can be scored easily and at single cell resolution. The C. elegans lin-3 gene encodes an epidermal growth factor family (EGF growth factor. lin-3 is expressed in the gonadal anchor cell and acts through LET-23 (transmembrane protein tyrosine kinase and ortholog of EGF receptor to signal the vulval precursor cells to generate vulval tissue. lin-3 is expressed in the vulval cells later, and recent evidence raises the possibility that lin-3 acts in the vulval cells as a relay signal during vulval induction. It is thus of interest to test the site of action of lin-3 by mosaic analysis. Results We visualized transgenes in living C. elegans by targeting the green fluorescent protein (GFP via the E. coli lac repressor (LacI to a specific 256 sequence repeat of the lac operator (lacO incorporated into transgenes. We engineered animals to express a nuclear-localized GFP-LacI fusion protein. C. elegans cells having a lacO transgene result in nuclear-localized bright spots (i.e., GFP-LacI bound to lacO. Cells with diffuse nuclear fluorescence correspond to unbound nuclear localized GFP-LacI. We detected chromosomes in living animals by chromosomally integrating the array of the lacO repeat sequence and visualizing the integrated transgene with GFP-LacI. This detection system can be applied to determine polyploidy as well as investigating chromosome segregation. To assess the GFP-LacI•lacO system as a marker for mosaic analysis, we conducted genetic mosaic analysis of the epidermal growth factor lin-3, expressed in the anchor cell. We establish that lin-3 acts in the anchor cell to induce vulva development

  7. Cell fate patterning during C. elegans vulval development

    OpenAIRE

    Hill, Russell J.; Sternberg, Paul W.

    1993-01-01

    Precursor cells of the vulva of the C. elegans hermaphrodite choose between two vulval cell fates (1° and 2°) and a non-vulval epidermal fate (3°) in response to three intercellular signals. An inductive signal produced by the anchor cell induces the vulval precursors to assume the 1° and 2° vulval fates. This inductive signal is an EGF-like growth factor encoded by the gene lin-3. An inhibitory signal mediated by lin-15, and which may originate from the surrounding epidermis, prevents the vu...

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

    Science.gov (United States)

    Ardiel, Evan L; Rankin, Catharine H

    2010-04-01

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

  9. 4-Phenylcoumarins from Mesua elegans with acetylcholinesterase inhibitory activity.

    Science.gov (United States)

    Awang, Khalijah; Chan, Gomathi; Litaudon, Marc; Ismail, Nor Hadiani; Martin, Marie-Thérèse; Gueritte, Françoise

    2010-11-15

    A significant acetylcholinesterase (AChE) inhibitory activity was observed for the hexane extract from the bark of Mesua elegans (Clusiaceae). Thus, the hexane extract was subjected to chemical investigation, which led to the isolation of nine 4-phenylcoumarins, in which three are new; mesuagenin A (1), mesuagenin C (3), mesuagenin D (4) and one new natural product; mesuagenin B (2). The structures of the isolated compounds were characterized by spectroscopic data interpretation, especially 1D and 2D NMR. Four compounds showed significant AChE inhibitory activity, with mesuagenin B (2) being the most potent (IC(50)=0.7μM). Copyright © 2010. Published by Elsevier Ltd.

  10. Apophysomyces elegans causing acute otogenic cervicofacial zygomycosis involving salivary glands.

    Science.gov (United States)

    Goyal, Amit; Tyagi, Isha; Syal, Rajan; Marak, R S K; Singh, Jagdeep

    2007-08-01

    Zygomycosis is an invasive, life threatening fungal infection that usually affects immunocompromised hosts. In the head and neck region, rhino-orbito-cerebral zygomycosis is more common than the cervicofacial variety. We report the first case of otogenic cervicofacial zygomycosis caused by Apophysomyces elegans involving the salivary glands, an uncommon site of infection. The case began after a trivial trauma in a diabetic patient and despite surgical debridement and liposomal amphotericin B therapy, the patient died due to extensive involvement and metabolic/hemodynamic complications.

  11. Google matrix analysis of C.elegans neural network

    Energy Technology Data Exchange (ETDEWEB)

    Kandiah, V., E-mail: kandiah@irsamc.ups-tlse.fr; Shepelyansky, D.L., E-mail: dima@irsamc.ups-tlse.fr

    2014-05-01

    We study the structural properties of the neural network of the C.elegans (worm) from a directed graph point of view. The Google matrix analysis is used to characterize the neuron connectivity structure and node classifications are discussed and compared with physiological properties of the cells. Our results are obtained by a proper definition of neural directed network and subsequent eigenvector analysis which recovers some results of previous studies. Our analysis highlights particular sets of important neurons constituting the core of the neural system. The applications of PageRank, CheiRank and ImpactRank to characterization of interdependency of neurons are discussed.

  12. 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.

  13. Folate status of gut microbiome affects Caenorhabditis elegans lifespan

    Directory of Open Access Journals (Sweden)

    Nguyen Theresa PT

    2012-07-01

    Full Text Available Abstract In a paper in BMC Biology Virk et al. show that Caenorhabditis elegans lifespan is extended in response to a diet of folate-deficient Escherichia coli. The deficiencies in folate biosynthesis were due to an aroD mutation, or treatment of E. coli with sulfa drugs, which are mimics of the folate precursor para-aminobenzoic acid. This study suggests that pharmacological manipulation of the gut microbiome folate status may be a viable approach to slow animal aging, and raises questions about folate supplementation. See research article http://www.http://www.biomedcentral.com/1741-7007/10/67

  14. Four acetylcholinesterase genes in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Arpagaus, M; Combes, D; Culetto, E; Grauso, M; Fedon, Y; Romani, R; Toutant, J P

    1998-01-01

    Whereas a single gene encodes acetylcholinesterase (AChE) in vertebrates and most insect species, four distinct genes have been cloned and characterized in the nematode Caenorhabditis elegans. We found that ace-1 (mapped to chromosome X) is prominently expressed in muscle cells whereas ace-2 (located on chromosome I) is mainly expressed in neurons. Ace-x and ace-y genes are located in close proximity on chromosome II where they are separated by only a few hundred base pairs. The role of these two genes is still unknown.

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

    Science.gov (United States)

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

    2015-09-19

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

  16. Dialogue between E. coli free radical pathways and the mitochondria of C. elegans

    Science.gov (United States)

    Govindan, J. Amaranath; Jayamani, Elamparithi; Zhang, Xinrui; Mylonakis, Eleftherios; Ruvkun, Gary

    2015-01-01

    The microbial world presents a complex palette of opportunities and dangers to animals, which have developed surveillance and response strategies to hints of microbial intent. We show here that the mitochondrial homeostatic response pathway of the nematode Caenorhabditis elegans responds to Escherichia coli mutations that activate free radical detoxification pathways. Activation of C. elegans mitochondrial responses could be suppressed by additional mutations in E. coli, suggesting that C. elegans responds to products of E. coli to anticipate challenges to its mitochondrion. Out of 50 C. elegans gene inactivations known to mediate mitochondrial defense, we found that 7 genes were required for C. elegans response to a free radical producing E. coli mutant, including the bZip transcription factor atfs-1 (activating transcription factor associated with stress). An atfs-1 loss-of-function mutant was partially resistant to the effects of free radical-producing E. coli mutant, but a constitutively active atfs-1 mutant growing on wild-type E. coli inappropriately activated the pattern of mitochondrial responses normally induced by an E. coli free radical pathway mutant. Carbonylated proteins from free radical-producing E. coli mutant may directly activate the ATFS-1/bZIP transcription factor to induce mitochondrial stress response: feeding C. elegans with H2O2-treated E. coli induces the mitochondrial unfolded protein response, and inhibition of a gut peptide transporter partially suppressed C. elegans response to free radical damaged E. coli. PMID:26392561

  17. Dialogue between E. coli free radical pathways and the mitochondria of C. elegans.

    Science.gov (United States)

    Govindan, J Amaranath; Jayamani, Elamparithi; Zhang, Xinrui; Mylonakis, Eleftherios; Ruvkun, Gary

    2015-10-06

    The microbial world presents a complex palette of opportunities and dangers to animals, which have developed surveillance and response strategies to hints of microbial intent. We show here that the mitochondrial homeostatic response pathway of the nematode Caenorhabditis elegans responds to Escherichia coli mutations that activate free radical detoxification pathways. Activation of C. elegans mitochondrial responses could be suppressed by additional mutations in E. coli, suggesting that C. elegans responds to products of E. coli to anticipate challenges to its mitochondrion. Out of 50 C. elegans gene inactivations known to mediate mitochondrial defense, we found that 7 genes were required for C. elegans response to a free radical producing E. coli mutant, including the bZip transcription factor atfs-1 (activating transcription factor associated with stress). An atfs-1 loss-of-function mutant was partially resistant to the effects of free radical-producing E. coli mutant, but a constitutively active atfs-1 mutant growing on wild-type E. coli inappropriately activated the pattern of mitochondrial responses normally induced by an E. coli free radical pathway mutant. Carbonylated proteins from free radical-producing E. coli mutant may directly activate the ATFS-1/bZIP transcription factor to induce mitochondrial stress response: feeding C. elegans with H2O2-treated E. coli induces the mitochondrial unfolded protein response, and inhibition of a gut peptide transporter partially suppressed C. elegans response to free radical damaged E. coli.

  18. Caenorhabditis elegans as a model for studying Cronobacter sakazakii ATCC BAA-894 pathogenesis.

    Science.gov (United States)

    Sivamaruthi, Bhagavathi Sundaram; Ganguli, Abhijit; Kumar, Mukesh; Bhaviya, Sheker; Pandian, Shunmugiah Karutha; Balamurugan, Krishnaswamy

    2011-10-01

    Cronobacter sakazakii is occasionally associated with food-borne illness seen in neonates and infants with weakened immune system. It can cause meningitis, local necrotizing enterocolitis and systemic bacteremia leading to infant mortality rates upto 33-80%. With the aim of investigating whether C. sakazakii is also a pathogen of the model organism C. elegans, we have performed killing assays and monitored the mortality of host fed with pathogen. C. elegans fed with C. sakazakii die over the course of several days, as a consequence of an accumulation of bacteria in the host intestine. Further, the rate of C. sakazakii mediated infection in C. elegans depends on the accumulation of the bacterial load inside the host. C. sakazakii killed C. elegans with an LT(50) (time for half to die) of 134 ± 2.8 h in liquid assay conditions, whereas the mortality of C. elegans infected with C. sakazakii was less pronounced during solid assays. We found that 24 h of C. sakazakii infection is enough to cause gametogenesis defects and increased cell damage in intestinal tract of host. To monitor the immune regulations during C. sakazakii infection in C. elegans at molecular level, total RNA was isolated and few candidate genes (lys-7, clec-60 and clec-87) were kinetically analyzed by using the semi-quantitative RT-PCR. The level of expression of lys-7, clec-60 and clec-87 mRNAs isolated from C. elegans infected with C. sakazakii was significantly higher when compared to C. elegans exposed to E. coli OP50 control. This is the first report in which physiological changes and an induction of host immunity mediated antimicrobial genes by C. sakazakii are shown in C. elegans.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-12-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  1. Dissecting the C. elegans response during infection using quantitative proteomics

    DEFF Research Database (Denmark)

    Simonsen, Karina Trankjær; Møller-Jensen, Jakob; Kristensen, Anders Riis;

    the infection process is followed using GFP-expressing bacteria and persistence assays. A quantitative proteomic approach was used to follow the C. elegans host response during the infection process. C. elegans were metabolic labeled with the stable isotope 15N and samples from three different time points...... process. By analyzing the changes in the C. elegans proteome throughout infection we will be able to identify and follow pathways and effector proteins in the early, mid and late phase of the innate immune response towards this pathogenic E. coli.  ...

  2. Nocardia elegans infection: a case report and literature review

    Directory of Open Access Journals (Sweden)

    Itaru Nakamura

    2017-01-01

    Full Text Available A case of disseminated nocardiosis caused by Nocardia elegans in a 72-year-old man with rheumatoid arthritis, treated with tacrolimus and prednisolone, is reported herein. The patient had impaired vision and was diagnosed with endophthalmitis and an abdominal skin abscess. He was started on trimethoprim–sulfamethoxazole treatment, followed by cefepime. The patient was then switched to a combination of imipenem–cilastatin and minocycline. Although the patient survived as a result of surgery and prolonged antibiotic treatment, he eventually lost vision after the infection became resistant to antibiotic treatment. Molecular analysis of samples from the abscess and vitreous fluid confirmed the extremely rare pathogen N. elegans, which accounts for only 0.3–0.6% of infections caused by Nocardia species. This organism is almost always associated with pulmonary infection, and disseminated infections are rare. As with previously reported norcardial infections, the current case was treated successfully with trimethoprim–sulfamethoxazole, carbapenems, and aminoglycosides. However, the clinical characteristics of this organism remain unclear. Further studies are therefore required to develop more effective treatment protocols for disseminated nocardiosis caused by this problematic pathogen.

  3. Cell cycle controls stress response and longevity in C. elegans

    Science.gov (United States)

    Dottermusch, Matthias; Lakner, Theresa; Peyman, Tobias; Klein, Marinella; Walz, Gerd; Neumann-Haefelin, Elke

    2016-01-01

    Recent studies have revealed a variety of genes and mechanisms that influence the rate of aging progression. In this study, we identified cell cycle factors as potent regulators of health and longevity in C. elegans. Focusing on the cyclin-dependent kinase 2 (cdk-2) and cyclin E (cye-1), we show that inhibition of cell cycle genes leads to tolerance towards environmental stress and longevity. The reproductive system is known as a key regulator of longevity in C. elegans. We uncovered the gonad as the central organ mediating the effects of cell cycle inhibition on lifespan. In particular, the proliferating germ cells were essential for conferring longevity. Steroid hormone signaling and the FOXO transcription factor DAF-16 were required for longevity associated with cell cycle inhibition. Furthermore, we discovered that SKN-1 (ortholog of mammalian Nrf proteins) activates protective gene expression and induces longevity when cell cycle genes are inactivated. We conclude that both, germline absence and inhibition through impairment of cell cycle machinery results in longevity through similar pathways. In addition, our studies suggest further roles of cell cycle genes beyond cell cycle progression and support the recently described connection of SKN-1/Nrf to signals deriving from the germline. PMID:27668945

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

    Science.gov (United States)

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

    1999-01-01

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

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

    Science.gov (United States)

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

    2015-01-27

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

  6. A distributed chemosensory circuit for oxygen preference in C. elegans.

    Directory of Open Access Journals (Sweden)

    Andy J Chang

    2006-09-01

    Full Text Available The nematode Caenorhabditis elegans has complex, naturally variable behavioral responses to environmental oxygen, food, and other animals. C. elegans detects oxygen through soluble guanylate cyclase homologs (sGCs and responds to it differently depending on the activity of the neuropeptide receptor NPR-1: npr-1(lf and naturally isolated npr-1(215F animals avoid high oxygen and aggregate in the presence of food; npr-1(215V animals do not. We show here that hyperoxia avoidance integrates food with npr-1 activity through neuromodulation of a distributed oxygen-sensing network. Hyperoxia avoidance is stimulated by sGC-expressing oxygen-sensing neurons, nociceptive neurons, and ADF sensory neurons. In npr-1(215V animals, the switch from weak aerotaxis on food to strong aerotaxis in its absence requires close regulation of the neurotransmitter serotonin in the ADF neurons; high levels of ADF serotonin promote hyperoxia avoidance. In npr-1(lf animals, food regulation is masked by increased activity of the oxygen-sensing neurons. Hyperoxia avoidance is also regulated by the neuronal TGF-beta homolog DAF-7, a secreted mediator of crowding and stress responses. DAF-7 inhibits serotonin synthesis in ADF, suggesting that ADF serotonin is a convergence point for regulation of hyperoxia avoidance. Coalitions of neurons that promote and repress hyperoxia avoidance generate a subtle and flexible response to environmental oxygen.

  7. Do proximate, C. elegans swimmers synchronize their gait?

    Science.gov (United States)

    Yuan, Jinzhou; Raizen, David; Bau, Haim

    2012-11-01

    We imaged two C. elegans swimming, one after the other, in a tapered conduit. The conduit was subjected to a DC electric field, with the negative pole at the narrow end and applied flow directed from the narrow end. As a result of their attraction to the negative pole (electrotaxis), both animals swam upstream. As the conduit narrowed, the average adverse flow velocity increased and the swimming speed of the leading animal decreased faster than that of the trailing animal, allowing the latter to catch up with the former. We quantified synchronization by measuring the phase lag between the gait of one animal and the extended wave pattern of the other as a function of the distance between the two animals. Only when the distance between the two animals' body centers was nearly equal to or smaller than one body length were the animals' motions synchronized. When the nematodes were parallel to one another, synchronization was essential to prevent the animals from colliding. Direct numerical simulations indicate that when the trailing animal's head is immediately downstream of the leading animal's tail, the animals derive just a slight hydrodynamic advantage from their proximity compared to a single swimmer. We thank Kun He Lee from the University of Pennsylvania for preparing C. elegans.

  8. Male Sterile Lines of Zinnia elegans and Their Cytological Observations

    Institute of Scientific and Technical Information of China (English)

    YE Yao-mei; HU Qiu-shi; CHEN Tian-hua; BAO Man-zhu

    2008-01-01

    In order to find out a new pathway for utilizing heterosis of Zinnia elegans and accelerate breeding process, the mechanism of anther development of a male sterile line was explored. Backcross, sibmating, selfing of fertile plants and testcross with inbred lines were analyzed and identified in the field, and cytology was observed. Recessive nucleus male sterile line AH209AB capable of being a maintainer was obtained by successive backcrosses with male sterile plants and fertile F, plants as male parents. Cytological and anatomical studies indicated that: (1) The wall of normal anther was constituted of four layers of cells such as epidermis, powder chamber wall, middle level and tapetum cells. The process in meiosis of pollen mother cell in Zinnia elegans was normal and cytoplasm divided simultanously. Mature pollen grain was tricellular type. (2) The petal of male sterile plant degraded as a thread-like structure, the stamens were villiform in appearance and no pollens were formed. The result showed that the anther of male sterile plant no longer proceed to differentiate spore mother cell and the pollen sac after the formation of the tissue of sporogenous cells, there was no evident boundary between tapetum cell, middle lamella and inner wall of PMC, tapetal cells did not develop from the very beginning. So the abortion type was completely structural male sterility. The male sterile line belongs to non-sporange male sterile type and is of great use in F1 seeds production.

  9. Translational control in the Caenorhabditis elegans germ line.

    Science.gov (United States)

    Nousch, Marco; Eckmann, Christian R

    2013-01-01

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

  10. Magnetosensitive neurons mediate geomagnetic orientation in Caenorhabditis elegans

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  12. High Throughput Interrogation of Behavioral Transitions in C. elegans

    Science.gov (United States)

    Liu, Mochi; Shaevitz, Joshua; Leifer, Andrew

    We present a high-throughput method to probe transformations from neural activity to behavior in Caenorhabditis elegans to better understand how organisms change behavioral states. We optogenetically deliver white-noise stimuli to target sensory or inter neurons while simultaneously recording the movement of a population of worms. Using all the postural movement data collected, we computationally classify stereotyped behaviors in C. elegans by clustering based on the spectral properties of the instantaneous posture. (Berman et al., 2014) Transitions between these behavioral clusters indicate discrete behavioral changes. To study the neural correlates dictating these transitions, we perform model-driven experiments and employ Linear-Nonlinear-Poisson cascades that take the white-noise stimulus as the input. The parameters of these models are fitted by reverse-correlation from our measurements. The parameterized models of behavioral transitions predict the worm's response to novel stimuli and reveal the internal computations the animal makes before carrying out behavioral decisions. Preliminary results are shown that describe the neural-behavioral transformation between neural activity in mechanosensory neurons and reversal behavior.

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

    Science.gov (United States)

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

    2014-04-01

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

  14. Gait Modulation in C. elegans: An Integrated Neuromechanical Model.

    Science.gov (United States)

    Boyle, Jordan H; Berri, Stefano; Cohen, Netta

    2012-01-01

    Equipped with its 302-cell nervous system, the nematode Caenorhabditis elegans adapts its locomotion in different environments, exhibiting so-called swimming in liquids and crawling on dense gels. Recent experiments have demonstrated that the worm displays the full range of intermediate behaviors when placed in intermediate environments. The continuous nature of this transition strongly suggests that these behaviors all stem from modulation of a single underlying mechanism. We present a model of C. elegans forward locomotion that includes a neuromuscular control system that relies on a sensory feedback mechanism to generate undulations and is integrated with a physical model of the body and environment. We find that the model reproduces the entire swim-crawl transition, as well as locomotion in complex and heterogeneous environments. This is achieved with no modulatory mechanism, except via the proprioceptive response to the physical environment. Manipulations of the model are used to dissect the proposed pattern generation mechanism and its modulation. The model suggests a possible role for GABAergic D-class neurons in forward locomotion and makes a number of experimental predictions, in particular with respect to non-linearities in the model and to symmetry breaking between the neuromuscular systems on the ventral and dorsal sides of the body.

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

    Science.gov (United States)

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

    2016-08-01

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

  16. Manganese Disturbs Metal and Protein Homeostasis in Caenorhabditis elegans

    Science.gov (United States)

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

    2014-01-01

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

  17. Curcumin-mediated lifespan extension in Caenorhabditis elegans.

    Science.gov (United States)

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

    2011-10-01

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

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

    Science.gov (United States)

    Hashimoto, Yasufumi; Ookuma, Sadatsugu; Nishida, Eisuke

    2009-06-01

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

  19. A sexually conditioned switch of chemosensory behavior in C. elegans.

    Directory of Open Access Journals (Sweden)

    Naoko Sakai

    Full Text Available In sexually reproducing animals, mating is essential for transmitting genetic information to the next generation and therefore animals have evolved mechanisms for optimizing the chance of successful mate location. In the soil nematode C. elegans, males approach hermaphrodites via the ascaroside pheromones, recognize hermaphrodites when their tails contact the hermaphrodites' body, and eventually mate with them. These processes are mediated by sensory signals specialized for sexual communication, but other mechanisms may also be used to optimize mate location. Here we describe associative learning whereby males use sodium chloride as a cue for hermaphrodite location. Both males and hermaphrodites normally avoid sodium chloride after associative conditioning with salt and starvation. However, we found that males become attracted to sodium chloride after conditioning with salt and starvation if hermaphrodites are present during conditioning. For this conditioning, which we call sexual conditioning, hermaphrodites are detected by males through pheromonal signaling and additional cue(s. Sex transformation experiments suggest that neuronal sex of males is essential for sexual conditioning. Altogether, these results suggest that C. elegans males integrate environmental, internal and social signals to determine the optimal strategy for mate location.

  20. A sexually conditioned switch of chemosensory behavior in C. elegans.

    Science.gov (United States)

    Sakai, Naoko; Iwata, Ryo; Yokoi, Saori; Butcher, Rebecca A; Clardy, Jon; Tomioka, Masahiro; Iino, Yuichi

    2013-01-01

    In sexually reproducing animals, mating is essential for transmitting genetic information to the next generation and therefore animals have evolved mechanisms for optimizing the chance of successful mate location. In the soil nematode C. elegans, males approach hermaphrodites via the ascaroside pheromones, recognize hermaphrodites when their tails contact the hermaphrodites' body, and eventually mate with them. These processes are mediated by sensory signals specialized for sexual communication, but other mechanisms may also be used to optimize mate location. Here we describe associative learning whereby males use sodium chloride as a cue for hermaphrodite location. Both males and hermaphrodites normally avoid sodium chloride after associative conditioning with salt and starvation. However, we found that males become attracted to sodium chloride after conditioning with salt and starvation if hermaphrodites are present during conditioning. For this conditioning, which we call sexual conditioning, hermaphrodites are detected by males through pheromonal signaling and additional cue(s). Sex transformation experiments suggest that neuronal sex of males is essential for sexual conditioning. Altogether, these results suggest that C. elegans males integrate environmental, internal and social signals to determine the optimal strategy for mate location.

  1. Gait modulation in C. elegans: An integrated neuromechanical model

    Directory of Open Access Journals (Sweden)

    Jordan Hylke Boyle

    2012-03-01

    Full Text Available Equipped with its 302-cell nervous system, the nematode Caenorhabditis elegans adapts its locomotion in different environments, exhibiting so-called swimming in liquids and crawling on dense gels. Recent experiments have demonstrated that the worm displays the full range of intermediate behaviors when placed in intermediate environments. The continuous nature of this transition strongly suggests that these behaviors all stem from modulation of a single underlying mechanism. Wepresent a model of C. elegans forward locomotion that includes a neuromuscular control system that relies on a sensory feedback mechanism to generate undulations and is integrated with a physical model of the body and environment. We find that the model reproduces the entire swim-crawl transition, as well as locomotion in complex and heterogeneous environments. This is achieved with no modulatory mechanism, except via the proprioceptive response to the physical environment. Manipulations of the model are used to dissect the proposed pattern generation mechanism and its modulation. The model suggests a possible role for GABAergic D-class neurons in forward locomotion and makes a number of experimentalpredictions, in particular with respect to nonlinearities in the model and to symmetry breaking between the neuromuscular systems on the ventral and dorsal sides of the body.

  2. Systematic analysis of pleiotropy in C. elegans early embryogenesis.

    Directory of Open Access Journals (Sweden)

    Lihua Zou

    2008-02-01

    Full Text Available Pleiotropy refers to the phenomenon in which a single gene controls several distinct, and seemingly unrelated, phenotypic effects. We use C. elegans early embryogenesis as a model to conduct systematic studies of pleiotropy. We analyze high-throughput RNA interference (RNAi data from C. elegans and identify "phenotypic signatures", which are sets of cellular defects indicative of certain biological functions. By matching phenotypic profiles to our identified signatures, we assign genes with complex phenotypic profiles to multiple functional classes. Overall, we observe that pleiotropy occurs extensively among genes involved in early embryogenesis, and a small proportion of these genes are highly pleiotropic. We hypothesize that genes involved in early embryogenesis are organized into partially overlapping functional modules, and that pleiotropic genes represent "connectors" between these modules. In support of this hypothesis, we find that highly pleiotropic genes tend to reside in central positions in protein-protein interaction networks, suggesting that pleiotropic genes act as connecting points between different protein complexes or pathways.

  3. Plant adaptogens increase lifespan and stress resistance in C. elegans.

    Science.gov (United States)

    Wiegant, F A C; Surinova, S; Ytsma, E; Langelaar-Makkinje, M; Wikman, G; Post, J A

    2009-02-01

    Extracts of plant adaptogens such as Eleutherococcus senticosus (or Acanthopanax senticosus) and Rhodiola rosea can increase stress resistance in several model systems. We now show that both extracts also increase the mean lifespan of the nematode C. elegans in a dose-dependent way. In at least four independent experiments, 250 microg/ml Eleutherococcus (SHE-3) and 10-25 microg/ml Rhodiola (SHR-5) significantly increased life span between 10 and 20% (P adaptogen extracts were also able to increase stress resistance in C. elegans: against a relatively short heat shock (35 degrees C during 3 h) as well as chronic heat treatment at 26 degrees C. An increase against chronic oxidative stress conditions was observed in mev-1 mutants, and during exposure of the wild type nematode to paraquat (10 mM) or UV stress, be it less efficiently. Concerning the mode of action: both adaptogens induce translocation of the DAF-16 transcription factor from the cytoplasm into the nucleus, suggesting a reprogramming of transcriptional activities favoring the synthesis of proteins involved in stress resistance (such as the chaperone HSP-16) and longevity. Based on these observations, it is suggested that adaptogens are experienced as mild stressors at the lifespan-enhancing concentrations and thereby induce increased stress resistance and a longer lifespan.

  4. C. elegans as a model organism for in vivo screening in cancer: effects of human c-Met in lung cancer affect C. elegans vulva phenotypes.

    Science.gov (United States)

    Siddiqui, Shahid S; Loganathan, Sivakumar; Krishnaswamy, Soundararajan; Faoro, Leonardo; Jagadeeswaran, Ramasamy; Salgia, Ravi

    2008-06-01

    Cancers typically harbour several mutant forms of key cellular genes that contribute to its complex phenotype. Our lab has previously identified gain-of-function mutations in some of the receptor tyrosine kinases such as c-Met in lung cancer. In order to investigate the mutant gene in the context of a whole organism, the current choice of in vivo model is limited to the mouse. To rapidly screen the functional aspects of mutant forms of c-Met detected in lung cancer, we used the nematode C. elegans as the model organism. Transgenic worms were generated that harbour wild type or the frequently seen mutant forms of c-Met in lung cancer (c-MetR988C and c-MetT1010I). Expression of the mutant human c-Met forms in C. elegans consistently resulted in significantly low fecundity and abnormal vulval development characterized by hyperplasia. Interestingly, exposure of c-Met mutant transgenic worms to nicotine resulted in enhanced abnormal vulval development, fecundity and locomotion. Our studies provide first evidence that human c-Met mutations can be studied in C. elegans, and that carcinogens can enhance mutant c-Met function expressed in C. elegans transgenic animals. We therefore propose the use of C. elegans as a model to rapidly assess the role of cancer specific gene mutations in the context of a whole organism.

  5. Genetic control of programmed cell death in the nematode Caenorhabditis elegans

    National Research Council Canada - National Science Library

    Horvitz, H R

    1999-01-01

    Studies of the development of the nematode Caenorhabditis elegans established that programmed cell death involves specific genes and proteins and that those genes and proteins act within the cells that die...

  6. Illigera elegans (Hernandiaceae), a ner species from Christmas Island, Indian Ocean

    NARCIS (Netherlands)

    Duyfjes, B.E.E.

    1994-01-01

    Illigera elegans (Hernandiaceae) is described as a new species. The species is remarkable because it has uncleft staminal appendages, a condition up till now only found in two other species, from New Guinea and East Africa (Madagascar, Tanzania), respectively.

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

    Science.gov (United States)

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

    2014-12-16

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

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

    Science.gov (United States)

    Gupta, Bhagwati P; Sternberg, Paul W

    2003-01-01

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

  9. Characterization of the interaction between the human pathogen Listeria monocytogenes and the model host C. elegans

    DEFF Research Database (Denmark)

    Simonsen, Karina Trankjær; Nielsen, Jesper Sejrup; Thomsen, Line E.;

    . elegans. Finally, we have developed a liquid based killing assay which enables us to set up a high-throughput screening system for the identification of L. monocytogenes virulence genes required for host-pathogen interactions.     References:   [1]: Kurz, C. L., and Ewbank, J. J. (2007) Curr Opin....... In addition, C. elegans is a promising model for the identification of novel virulence factors in various pathogens. A large number of human, animal, plant and insect pathogens have been shown to kill the worm, when C. elegans was allowed to feed on pathogens in stead of its normal laboratory diet [1......, which has been shown to kill C. elegans through the production of a toxic secondary metabolite [3] and Staphylococcus aureus, which establishes a persistent infection in the gut of the worm, leading to its death [4].   Recently, the facultative intracellular human pathogen Listeria monocytogenes has...

  10. Dopamine receptor type 1 of Caenorhabditis elegans expressing in mechanosensory neurons

    Directory of Open Access Journals (Sweden)

    Bondarchuk T. I.

    2012-01-01

    Full Text Available Until now the results on profiling dopamine receptors in C. elegans have been incomplete and fragmentary. The aim of this study was to investigate the expression profile of dop-1 gene in C. elegans using 3 kb promoter with 3'-end locating before ATG of dop-1 gene. Methods. The strain of C. elegans with mutant unc-119 gene was used. To check a pattern of the dop-1 expression, the promoter of this gene was amplified using PCR. The animals were co-bombarded with plasmid pPD95.77 dop-1::GFP and reporter construct containing unc-119 gene. Results. Using GFP as a reporter protein, we built a whole picture of expression of dopamine receptor type 1 in C. elegans and found that this protein could be detected only in mechanosensory neurons such as PLM, PVQR, PVQL, ALNR, ALNL, DVAR, DVC.

  11. C. elegans major fats are stored in vesicles distinct from lysosome-related organelles.

    Science.gov (United States)

    O'Rourke, Eyleen J; Soukas, Alexander A; Carr, Christopher E; Ruvkun, Gary

    2009-11-01

    Genetic conservation allows ancient features of fat storage endocrine pathways to be explored in C. elegans. Multiple studies have used Nile red or BODIPY-labeled fatty acids to identify regulators of fat mass. When mixed with their food, E. coli bacteria, Nile red, and BODIPY-labeled fatty acids stain multiple spherical cellular structures in the C. elegans major fat storage organ, the intestine. However, here we demonstrate that, in the conditions previously reported, the lysosome-related organelles stained by Nile red and BODIPY-labeled fatty acids are not the C. elegans major fat storage compartment. We show that the major fat stores are contained in a distinct cellular compartment that is not stained by Nile red. Using biochemical assays, we validate oil red O staining as a method to assess major fat stores in C. elegans, allowing for efficient and accurate genetic and functional genomic screens for genes that control fat accumulation at the organismal level.

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

    Science.gov (United States)

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

    2014-08-01

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

  13. Acute behavioral responses to pheromones in C. elegans (adult behaviors: attraction, repulsion).

    Science.gov (United States)

    Jang, Heeun; Bargmann, Cornelia I

    2013-01-01

    The pheromone drop test is a simple and robust behavioral assay to quantify acute avoidance of pheromones in C. elegans, and the suppression of avoidance by attractive pheromones. In the pheromone drop test, water-soluble C. elegans pheromones are individually applied to animals that are freely moving on a large plate. Upon encountering a repellent, each C. elegans animal may or may not try to escape by making a long reversal. The fraction of animals that make a long reversal response indicates the repulsiveness of a given pheromone to a specific genotype/strain of C. elegans. Performing the drop test in the presence of bacterial food enhances the avoidance response to pheromones. Attraction to pheromones can be assayed by the suppression of reversals to repulsive pheromones or by the suppression of the basal reversal rate to buffer.

  14. Profiling the anaerobic response of C. elegans using GC-MS.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Butler

    Full Text Available The nematode Caenorhabditis elegans is a model organism that has seen extensive use over the last four decades in multiple areas of investigation. In this study we explore the response of the nematode Caenorhabditis elegans to acute anoxia using gas-chromatography mass-spectrometry (GC-MS. We focus on the readily-accessible worm exometabolome to show that C. elegans are mixed acid fermenters that utilize several metabolic pathways in unconventional ways to remove reducing equivalents - including partial reversal of branched-chain amino acid catabolism and a potentially novel use of the glyoxylate pathway. In doing so, we provide detailed methods for the collection and analysis of excreted metabolites that, with minimal adjustment, should be applicable to many other species. We also describe a procedure for collecting highly volatile compounds from C. elegans. We are distributing our mass spectral library in an effort to facilitate wider use of metabolomics.

  15. Shape memory alloy-based small crawling robots inspired by C. elegans

    Energy Technology Data Exchange (ETDEWEB)

    Yuk, Hyunwoo; Kim, Daeyeon; Shin, Jennifer H [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Lee, Honggu; Jo, Sungho, E-mail: shjo@kaist.ac.kr, E-mail: j_shin@kaist.ac.kr [Department of Computer Science, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of)

    2011-12-15

    Inspired by its simple musculature, actuation and motion mechanisms, we have developed a small crawling robot that closely mimics the model organism of our choice: Caenorhabditis elegans. A thermal shape memory alloy (SMA) was selected as an actuator due to the similarities of its properties to C. elegans muscles. Based on the anatomy of C. elegans, a 12-unit robot was designed to generate a sinusoidal undulating motion. Each body unit consisting of a pair of SMA actuators is serially connected by rigid links with an embedded motion control circuit. A simple binary operation-based motion control mechanism was implemented using a microcontroller. The assembled robot can execute C. elegans-like motion with a 0.17 Hz undulation frequency. Its motion is comparable to that of a real worm.

  16. Analyzing modifiers of protein aggregation in C. elegans by native agarose gel electrophoresis

    NARCIS (Netherlands)

    Holmberg, Mats; Nollen, Ellen A A; Hatters, Danny M.; Hannan, Anthony J.

    2013-01-01

    The accumulation of specific aggregation-prone proteins during aging is thought to be involved in several diseases, most notably Alzheimer's and Parkinson's disease as well as polyglutamine expansion disorders such as Huntington's disease. Caenorhabditis elegans disease models with transgenic

  17. Interaction of a Free-Living Soil Nematode, Caenorhabditis elegans, with Surrogates of Foodborne Pathogenic Bacteria

    National Research Council Canada - National Science Library

    Anderson G.L; Caldwell K.N; Beuchat L.R; Williams P.L

    2003-01-01

    .... In this study, we evaluated the associations between a free-living soil nematode, Caenorhabditis elegans, and Escherichia coli, an avirulent strain of Salmonella Typhimurium, Listeria welshimeri, and Bacillus cereus...

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  1. 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.

  2. Shape memory alloy-based small crawling robots inspired by C. elegans.

    Science.gov (United States)

    Yuk, Hyunwoo; Kim, Daeyeon; Lee, Honggu; Jo, Sungho; Shin, Jennifer H

    2011-12-01

    Inspired by its simple musculature, actuation and motion mechanisms, we have developed a small crawling robot that closely mimics the model organism of our choice: Caenorhabditis elegans. A thermal shape memory alloy (SMA) was selected as an actuator due to the similarities of its properties to C. elegans muscles. Based on the anatomy of C. elegans, a 12-unit robot was designed to generate a sinusoidal undulating motion. Each body unit consisting of a pair of SMA actuators is serially connected by rigid links with an embedded motion control circuit. A simple binary operation-based motion control mechanism was implemented using a microcontroller. The assembled robot can execute C. elegans-like motion with a 0.17 Hz undulation frequency. Its motion is comparable to that of a real worm.

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

    Science.gov (United States)

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

    2014-09-21

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

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

    Science.gov (United States)

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

    2008-05-16

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

  5. WormBase as an Integrated Platform for the C. elegans ORFeome

    OpenAIRE

    Chen, Nansheng; Lawson, Daniel; Bradnam, Keith; Harris, Todd W.; Stein, Lincoln D.

    2004-01-01

    The ORFeome project has validated and corrected a large number of predicted gene models in the nematode C. elegans, and has provided an enormous resource for proteome-scale studies. To make the resource useful to the research and teaching community, it needs to be integrated with other large-scale data sets, including the C. elegans genome, cell lineage, neurological wiring diagram, transcriptome, and gene expression map. This integration is also critical because the ORFeome data sets, like o...

  6. 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.

  7. Homologous and unique G protein alpha subunits in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Lochrie, M A; Mendel, J E; Sternberg, P W; Simon, M I

    1991-01-01

    A cDNA corresponding to a known G protein alpha subunit, the alpha subunit of Go (Go alpha), was isolated and sequenced. The predicted amino acid sequence of C. elegans Go alpha is 80-87% identical to other Go alpha sequences. An mRNA that hybridizes to the C. elegans Go alpha cDNA can be detected on Northern blots. A C. elegans protein that crossreacts with antibovine Go alpha antibody can be detected on immunoblots. A cosmid clone containing the C. elegans Go alpha gene (goa-1) was isolated and mapped to chromosome I. The genomic fragments of three other C. elegans G protein alpha subunit genes (gpa-1, gpa-2, and gpa-3) have been isolated using the polymerase chain reaction. The corresponding cosmid clones were isolated and mapped to disperse locations on chromosome V. The sequences of two of the genes, gpa-1 and gpa-3, were determined. The predicted amino acid sequences of gpa-1 and gpa-3 are only 48% identical to each other. Therefore, they are likely to have distinct functions. In addition they are not homologous enough to G protein alpha subunits in other organisms to be classified. Thus C. elegans has G proteins that are identifiable homologues of mammalian G proteins as well as G proteins that appear to be unique to C. elegans. Study of identifiable G proteins in C. elegans may result in a further understanding of their function in other organisms, whereas study of the novel G proteins may provide an understanding of unique aspects of nematode physiology. Images PMID:1907494

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

    OpenAIRE

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

    2014-01-01

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

  9. C. elegans Major Fats Are Stored in Vesicles Distinct from Lysosome-Related Organelles

    OpenAIRE

    O’Rourke, Eyleen J.; Soukas, Alexander A.; Carr, Christopher E.; Ruvkun, Gary

    2009-01-01

    Genetic conservation allows ancient features of fat storage endocrine pathways to be explored in C. elegans. Multiple studies have used Nile red or BODIPY-labeled fatty acids to identify regulators of fat mass. When mixed with their food, E. coli bacteria, Nile red, and BODIPY-labeled fatty acids stain multiple spherical cellular structures in the C. elegans major fat storage organ, the intestine. However, here we demonstrate that, in the conditions previously reported, the lysosome-related o...

  10. C. elegans as a virulence model for E. coli strain 042

    OpenAIRE

    Kjærbo, Rasmus E. R.; Godballe, Troels; Hansen, Klaus G.; Petersen, Pernille D.; Tikander, Emil

    2010-01-01

    During the last decade the nematode Caenorhabditis elegans has been used to model the pathogenesis of several bacterial species. The emerging pathogen enteroaggregative Escherichia coli (EAEC) is a considerable cause of both acute and persistent diarrhea worldwide. Travellers to developing countries, immunocompromised people and young children are high-risk groups prone to infection. Virulence models using C. elegans might provide valuable information about the host-pathogen interactions whic...

  11. Natural Polymorphisms in C. elegans HECW-1 E3 Ligase Affect Pathogen Avoidance Behaviour

    OpenAIRE

    Chang, Howard C.; Paek, Jennifer; Dennis H Kim

    2011-01-01

    Heritable variation in behavioural traits generally has a complex genetic basis 1 , and thus naturally occurring polymorphisms that influence behaviour have been defined in only rare instances 2,3 . The isolation of wild strains of Caenorhabditis elegans has facilitated the study of natural genetic variation in this species 4 and provided insights into its diverse microbial ecology 5 . C. elegans responds to bacterial infection with conserved innate immune responses 6-8 and, while lacking the...

  12. 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...

  13. Using Expression Profiles of Caenorhabditis elegans Neurons To Identify Genes That Mediate Synaptic Connectivity

    OpenAIRE

    Leehod Baruch; Shalev Itzkovitz; Michal Golan-Mashiach; Ehud Shapiro; Eran Segal

    2008-01-01

    Authors Summary Synaptic wiring in the nematode Caenorhabditis elegans is largely invariant between individuals, suggesting that this wiring is genetically encoded. This is in essence the chemoaffinity hypothesis suggested by Roger Sperry. However, proving this hypothesis in model organisms and detecting the identities of the genes that determine the presence or absence of synaptic connections is a major challenge. C. elegans provides a unique opportunity to examine this hypothesis due to the...

  14. Distinct Pathogenesis and Host Responses during Infection of C. elegans by P. aeruginosa and S. aureus

    Science.gov (United States)

    Irazoqui, Javier E.; Troemel, Emily R.; Feinbaum, Rhonda L.; Luhachack, Lyly G.; Cezairliyan, Brent O.; Ausubel, Frederick M.

    2010-01-01

    The genetically tractable model host Caenorhabditis elegans provides a valuable tool to dissect host-microbe interactions in vivo. Pseudomonas aeruginosa and Staphylococcus aureus utilize virulence factors involved in human disease to infect and kill C. elegans. Despite much progress, virtually nothing is known regarding the cytopathology of infection and the proximate causes of nematode death. Using light and electron microscopy, we found that P. aeruginosa infection entails intestinal distention, accumulation of an unidentified extracellular matrix and P. aeruginosa-synthesized outer membrane vesicles in the gut lumen and on the apical surface of intestinal cells, the appearance of abnormal autophagosomes inside intestinal cells, and P. aeruginosa intracellular invasion of C. elegans. Importantly, heat-killed P. aeruginosa fails to elicit a significant host response, suggesting that the C. elegans response to P. aeruginosa is activated either by heat-labile signals or pathogen-induced damage. In contrast, S. aureus infection causes enterocyte effacement, intestinal epithelium destruction, and complete degradation of internal organs. S. aureus activates a strong transcriptional response in C. elegans intestinal epithelial cells, which aids host survival during infection and shares elements with human innate responses. The C. elegans genes induced in response to S. aureus are mostly distinct from those induced by P. aeruginosa. In contrast to P. aeruginosa, heat-killed S. aureus activates a similar response as live S. aureus, which appears to be independent of the single C. elegans Toll-Like Receptor (TLR) protein. These data suggest that the host response to S. aureus is possibly mediated by pathogen-associated molecular patterns (PAMPs). Because our data suggest that neither the P. aeruginosa nor the S. aureus–triggered response requires canonical TLR signaling, they imply the existence of unidentified mechanisms for pathogen detection in C. elegans, with

  15. Diverse and potentially manipulative signalling with ascarosides in the model nematode C. elegans

    OpenAIRE

    Diaz, Sylvia Anaid; Brunet, Vincent; Lloyd-Jones, Guy C; Spinner, William; Wharam, Barney; Viney, Mark

    2014-01-01

    Background Animals use environmental information to make developmental decisions to maximise their fitness. The nematode Caenorhabditis elegans measures its environment to decide between arresting development as dauer larvae or continuing to grow and reproduce. Worms are thought to use ascarosides as signals of population density and this signalling is thought to be a species-wide honest signal. We compared recently wild C. elegans lines’ dauer larva arrest when presented with the same ascaro...

  16. Chemosensory Cue Conditioning with Stimulants in a Caenorhabditis elegans Animal Model of Addiction

    OpenAIRE

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

    2012-01-01

    The underlying molecular mechanisms of drug abuse and addiction behaviors are poorly understood. C. elegans provide a simple, whole animal model with conserved molecular pathways well suited for studying the foundations of complex diseases. Historically, chemotaxis has been a measure used to examine sensory approach and avoidance behavior in worms. Chemotaxis can be modulated by previous experience, and cue-dependent conditioned learning has been demonstrated in C. elegans, but such condition...

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

    Directory of Open Access Journals (Sweden)

    Zetka Monique C

    2006-10-01

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

  18. Ultrastructure of the spermatozoon of the digenean Plagiorchis elegans (Rudolphi, 1802) (Plagiorchioidea, Plagiorchiidae).

    Science.gov (United States)

    Ndiaye, Papa Ibnou; Quilichini, Yann; Tkach, Vasyl V; Greiman, Stephen E; Bâ, Cheikh Tidiane; Marchand, Bernard

    2013-09-01

    The ultrastructure of the mature spermatozoon of the type genus of the Plagiorchiidae Plagiorchis elegans (Rudolphi, 1802), a parasite of the Golden hamster, Mesocricetus auratus is described. This study is the first ultrastructural study of the spermatozoon of a Plagiorchis, the second of a plagiorchiid species and only the third in the Plagiorchioidea. Previously data on spermatozoon ultrastructure existed only for the plagiorchiid Enodiotrema reductum and the omphalometrid Rubenstrema exasperatum. The mature spermatozoon of P. elegans exhibited the general pattern described in most digenean species, namely two axonemes of the 9 + "1" Trepaxonemata pattern, nucleus, mitochondria, external ornamentation of the plasma membrane, spine-like bodies, and glycogen granules. However, the rather typical expansion of the plasma membrane is not found in P. elegans. Another peculiarity of the spermatozoon of P. elegans is the presence of a structure called thin cytoplasm termination. Spermatozoon ultrastructure of P. elegans is compared with that of E. reductum and R. exasperatum. Spermatozoon of P. elegans conforms to the general pattern described in E. reductum. Thus, this study further expands our knowledge on the spermatozoon ultrastructure among the members of the Plagiorchioidea, one of the most phylogenetically derived groups of the digenea.

  19. A C. elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue.

    Science.gov (United States)

    Li, Wei; Feng, Zhaoyang; Sternberg, Paul W; Xu, X Z Shawn

    2006-03-30

    The nematode Caenorhabditis elegans is commonly used as a genetic model organism for dissecting integration of the sensory and motor systems. Despite extensive genetic and behavioural analyses that have led to the identification of many genes and neural circuits involved in regulating C. elegans locomotion behaviour, it remains unclear whether and how somatosensory feedback modulates motor output during locomotion. In particular, no stretch receptors have been identified in C. elegans, raising the issue of whether stretch-receptor-mediated proprioception is used by C. elegans to regulate its locomotion behaviour. Here we have characterized TRP-4, the C. elegans homologue of the mechanosensitive TRPN channel. We show that trp-4 mutant worms bend their body abnormally, exhibiting a body posture distinct from that of wild-type worms during locomotion, suggesting that TRP-4 is involved in stretch-receptor-mediated proprioception. We show that TRP-4 acts in a single neuron, DVA, to mediate its function in proprioception, and that the activity of DVA can be stimulated by body stretch. DVA both positively and negatively modulates locomotion, providing a unique mechanism whereby a single neuron can fine-tune motor activity. Thus, DVA represents a stretch receptor neuron that regulates sensory-motor integration during C. elegans locomotion.

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

    Science.gov (United States)

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

    2016-07-01

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

  1. 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.

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

    Science.gov (United States)

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

    2010-11-01

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

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

    Science.gov (United States)

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

    2015-11-25

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

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

    Science.gov (United States)

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

    2002-11-26

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

  5. Excessive folate synthesis limits lifespan in the C. elegans: E. coli aging model

    Directory of Open Access Journals (Sweden)

    Virk Bhupinder

    2012-07-01

    Full Text Available Abstract Background Gut microbes influence animal health and thus, are potential targets for interventions that slow aging. Live E. coli provides the nematode worm Caenorhabditis elegans with vital micronutrients, such as folates that cannot be synthesized by animals. However, the microbe also limits C. elegans lifespan. Understanding these interactions may shed light on how intestinal microbes influence mammalian aging. Results Serendipitously, we isolated an E. coli mutant that slows C. elegans aging. We identified the disrupted gene to be aroD, which is required to synthesize aromatic compounds in the microbe. Adding back aromatic compounds to the media revealed that the increased C. elegans lifespan was caused by decreased availability of para-aminobenzoic acid, a precursor to folate. Consistent with this result, inhibition of folate synthesis by sulfamethoxazole, a sulfonamide, led to a dose-dependent increase in C. elegans lifespan. As expected, these treatments caused a decrease in bacterial and worm folate levels, as measured by mass spectrometry of intact folates. The folate cycle is essential for cellular biosynthesis. However, bacterial proliferation and C. elegans growth and reproduction were unaffected under the conditions that increased lifespan. Conclusions In this animal:microbe system, folates are in excess of that required for biosynthesis. This study suggests that microbial folate synthesis is a pharmacologically accessible target to slow animal aging without detrimental effects.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-01-01

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

  7. 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.

  8. Anti-aging effect of polysaccharide from Bletilla striata on nematode Caenorhabditis elegans.

    Science.gov (United States)

    Zhang, Yusi; Lv, Ting; Li, Min; Xue, Ting; Liu, Hui; Zhang, Weiming; Ding, Xiaoyu; Zhuang, Ziheng

    2015-01-01

    Polysaccharide isolated from Bletilla striata, a well-known traditional Chinese medicine (Bletilla striata polysaccharide [BSP]) has been found to play important roles in endothelial cells proliferation, inducible nitric oxide stimulation, wound healing acceleration and other processes. Recent studies found that B. striata has anti-oxidative properties, however, potential anti-aging effects of BSP in whole organisms has not been characterized. To investigate whether BSP has anti-aging effects on Caenorhabditis elegans. After treatment with BSP, the lifespan, locomotion ability, and stress resistance of C. elegans was determined. To provide insight into the underlying mechanism for the anti-aging effect of BSP, we measured its effect on bacterial growth, brood size of C. elegans, and the insulin/insulin-like growth factor (IGF) signaling pathway. After BSP treatment, the lifespan of C. elegans was extended, and its locomotion ability and stress resistance were increased. BSP was found to have no effect on bacterial growth or on reproduction of C. elegans, However, mRNA levels of age-1 and hcf-1 were reduced after BSP treatment. Additionally, we observed that BSP did not extend the lifespan of daf-16 mutant animals. BSP produces an anti-aging effect on C. elegans through the insulin/IGF signaling pathway and holds promise for future development as a functional food.

  9. 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.

  10. 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.

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Hidetoshi Komatsu

    2008-08-01

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

  13. The C. elegans Opa1 homologue EAT-3 is essential for resistance to free radicals.

    Science.gov (United States)

    Kanazawa, Takayuki; Zappaterra, Mauro D; Hasegawa, Ayako; Wright, Ashley P; Newman-Smith, Erin D; Buttle, Karolyn F; McDonald, Kent; Mannella, Carmen A; van der Bliek, Alexander M

    2008-02-29

    The C. elegans eat-3 gene encodes a mitochondrial dynamin family member homologous to Opa1 in humans and Mgm1 in yeast. We find that mutations in the C. elegans eat-3 locus cause mitochondria to fragment in agreement with the mutant phenotypes observed in yeast and mammalian cells. Electron microscopy shows that the matrices of fragmented mitochondria in eat-3 mutants are divided by inner membrane septae, suggestive of a specific defect in fusion of the mitochondrial inner membrane. In addition, we find that C. elegans eat-3 mutant animals are smaller, grow slower, and have smaller broodsizes than C. elegans mutants with defects in other mitochondrial fission and fusion proteins. Although mammalian Opa1 is antiapoptotic, mutations in the canonical C. elegans cell death genes ced-3 and ced-4 do not suppress the slow growth and small broodsize phenotypes of eat-3 mutants. Instead, the phenotypes of eat-3 mutants are consistent with defects in oxidative phosphorylation. Moreover, eat-3 mutants are hypersensitive to paraquat, which promotes damage by free radicals, and they are sensitive to loss of the mitochondrial superoxide dismutase sod-2. We conclude that free radicals contribute to the pathology of C. elegans eat-3 mutants.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Yeu-Ching Shi

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

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

  17. The Mediator complex of Caenorhabditis elegans: insights into the developmental and physiological roles of a conserved transcriptional coregulator

    National Research Council Canada - National Science Library

    Grants, Jennifer M; Goh, Grace Y S; Taubert, Stefan

    2015-01-01

    .... Here, we review the current knowledge of Mediator subunit function in the nematode Caenorhabditis elegans, a metazoan in which established and emerging genetic technologies facilitate the study...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  20. An engineering approach to extending lifespan in C. elegans.

    Directory of Open Access Journals (Sweden)

    Dror Sagi

    Full Text Available We have taken an engineering approach to extending the lifespan of Caenorhabditis elegans. Aging stands out as a complex trait, because events that occur in old animals are not under strong natural selection. As a result, lifespan can be lengthened rationally using bioengineering to modulate gene expression or to add exogenous components. Here, we engineered longer lifespan by expressing genes from zebrafish encoding molecular functions not normally present in worms. Additionally, we extended lifespan by increasing the activity of four endogenous worm aging pathways. Next, we used a modular approach to extend lifespan by combining components. Finally, we used cell- and worm-based assays to analyze changes in cell physiology and as a rapid means to evaluate whether multi-component transgenic lines were likely to have extended longevity. Using engineering to add novel functions and to tune endogenous functions provides a new framework for lifespan extension that goes beyond the constraints of the worm genome.

  1. Radiation-induced gene expression in the nematode caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, G.A.; Jones, T.A.; Chesnut, A.; Smith, A.L. [Loma Linda Univ., CA (United States)

    2002-12-01

    We used the nematode C. elegans to characterize the genotoxic and cytotoxic effects of ionizing radiation in a simple animal model emphasizing the unique effects of charged particle radiation. Here we demonstrate by reverse transcription polymerase chain reaction (RT-PCR) differential display and whole genome microarray hybridization experiments that gamma rays, accelerated protons and iron ions at the same physical dose lead to unique transcription profiles. 599 of 17871 genes analyzed (3.4%) showed differential expression 3 hrs after exposure to 3 Gy of radiation. 193 were up-regulated, 406 were down-regulated and 90% were affected only by a single species of radiation. A novel statistical clustering technique identified the regulatory relationships between the radiation-modulated genes and showed that genes affected by each radiation species were associated with unique regulatory clusters. This suggests that independent homeostatic mechanisms are activated in response to radiation exposure as a function of track structure or ionization density. (author)

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

    Science.gov (United States)

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

    2016-01-01

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

  3. Flow-Based Network Analysis of the Caenorhabditis elegans Connectome

    Science.gov (United States)

    Bacik, Karol A.; Schaub, Michael T.; Billeh, Yazan N.; Barahona, Mauricio

    2016-01-01

    We exploit flow propagation on the directed neuronal network of the nematode C. elegans to reveal dynamically relevant features of its connectome. We find flow-based groupings of neurons at different levels of granularity, which we relate to functional and anatomical constituents of its nervous system. A systematic in silico evaluation of the full set of single and double neuron ablations is used to identify deletions that induce the most severe disruptions of the multi-resolution flow structure. Such ablations are linked to functionally relevant neurons, and suggest potential candidates for further in vivo investigation. In addition, we use the directional patterns of incoming and outgoing network flows at all scales to identify flow profiles for the neurons in the connectome, without pre-imposing a priori categories. The four flow roles identified are linked to signal propagation motivated by biological input-response scenarios. PMID:27494178

  4. Radiosensitivity Parameters For Lethal Mutagenesis In Caenorhabditis Elegans

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-01

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

  5. Crossover suppressors and balanced recessive lethals in Caenorhabditis elegans. [Nematode

    Energy Technology Data Exchange (ETDEWEB)

    Herman, R.K.

    1978-01-01

    Two dominant suppressors of crossing over have been identified following x-ray treatment of the small nematode C. elegans. They suppress crossing over in linkage group II (LGII) about 100-fold and 50-fold and are both tightly linked to LGII markers. One, called C1, segregates independently of all other linkage groups and is homozygous fertile. The other is a translocation involving LGII and X. The translocation also suppresses crossing over along the right half of X and is homozygous lethal. C1 has been used as a balancer of LGII recessive lethal and sterile mutations induced by EMS. The frequencies of occurrence of lethals and steriles were approximately equal. Fourteen mutations were assigned to complementation groups and mapped. They tended to map in the same region where LGII visibles are clustered.

  6. Anchor cell invasion into the vulval epithelium in C. elegans.

    Science.gov (United States)

    Sherwood, David R; Sternberg, Paul W

    2003-07-01

    An understanding of cell-invasive behavior has been limited by the lack of in vivo models where this activity can be clearly visualized and manipulated. We show that a single cell in the Caenorhabditis elegans gonad, the anchor cell (AC), initiates uterine-vulval contact through a cell invasion event. Using genetic analysis, laser ablations, and cell-specific markers, we demonstrate that AC invasion is predominantly stimulated by the 1 degrees vulval lineage cells, which generate a diffusible signal that promotes AC invasive behavior toward these cells and further targets invasive processes between the two central 1 degrees vulval lineage cells. We also show that AC invasion is regulated by the AC response to this cue, as well as a vulval-independent mechanism that weakly drives invasion. These studies dissect the regulatory mechanisms that underlie a simple cell-invasive behavior in vivo, and introduce AC invasion as a model for understanding key checkpoints controlling cell invasion.

  7. The epidermal growth factor system in Caenorhabditis elegans.

    Science.gov (United States)

    Moghal, Nadeem; Sternberg, Paul W

    2003-03-10

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

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

    Science.gov (United States)

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

    2006-01-31

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

  9. Widespread genetic incompatibility in C. elegans maintained by balancing selection.

    Science.gov (United States)

    Seidel, Hannah S; Rockman, Matthew V; Kruglyak, Leonid

    2008-02-01

    Natural selection is expected to eliminate genetic incompatibilities from interbreeding populations. We have discovered a globally distributed incompatibility in the primarily selfing species Caenorhabditis elegans that has been maintained despite its negative consequences for fitness. Embryos homozygous for a naturally occurring deletion of the zygotically acting gene zeel-1 arrest if their sperm parent carries an incompatible allele of a second, paternal-effect locus, peel-1. The two interacting loci are tightly linked, with incompatible alleles occurring in linkage disequilibrium in two common haplotypes. These haplotypes exhibit elevated sequence divergence, and population genetic analyses of this region indicate that natural selection is preserving both haplotypes in the population. Our data suggest that long-term maintenance of a balanced polymorphism has permitted the incompatibility to persist despite gene flow across the rest of the genome.

  10. Primary cutaneous mucormycosis (zygomycosis caused by Apophysomyces elegans

    Directory of Open Access Journals (Sweden)

    Reddy I

    2008-01-01

    Full Text Available A 53 year-old male diabetic presented with a month-old, painful ulcer with necrotic margins over the right thigh. Wound debridement was done twice and the ulcer showed recurrent growth of a white, cottony filamentous structure. Cutaneous mucormycosis was suspected and confirmed by histopathology and a culture isolate of Apophysomyces elegans . The patient was treated with liposomal amphotericin-B and itraconazole followed by partial thickness skin grafting, and then discharged after being prescribed posaconazole syrup for three weeks. Regular follow-up was done and during the last visit after six months following discharge, the ulcer was found to have healed well with no recurrence of the fungus.

  11. High-throughput behavioral analysis in C. elegans.

    Science.gov (United States)

    Swierczek, Nicholas A; Giles, Andrew C; Rankin, Catharine H; Kerr, Rex A

    2011-06-05

    We designed a real-time computer vision system, the Multi-Worm Tracker (MWT), which can simultaneously quantify the behavior of dozens of Caenorhabditis elegans on a Petri plate at video rates. We examined three traditional behavioral paradigms using this system: spontaneous movement on food, where the behavior changes over tens of minutes; chemotaxis, where turning events must be detected accurately to determine strategy; and habituation of response to tap, where the response is stochastic and changes over time. In each case, manual analysis or automated single-worm tracking would be tedious and time-consuming, but the MWT system allowed rapid quantification of behavior with minimal human effort. Thus, this system will enable large-scale forward and reverse genetic screens for complex behaviors.

  12. In vitro biological screening of the stem of Desmodium elegans

    Institute of Scientific and Technical Information of China (English)

    Arshad Khan; Rabia Usman; Ming-Liang Wang; Abdur Rauf; Naveed Muhammad; Akhatar Aman; Taha Hussein Musa Tahir

    2013-01-01

    Objective:To explore the medicinal importance of the stem of Desmodium elegans, methanolic extract, and its different solvent fractions were evaluated for brine shrimp lethality, insecticidal and phytotoxicity, antifungal, and antibacterial activities. Methods:The methanolic extract and its solvent fractions were tested for cytotoxic, phytotoxic, insecticidal, antifungal, and antibacterial effects using our previous published protocols. Results:The methanolic, DCM, ethyl acetate and n-butanol fractions exhibited insecticidal effect against Callosobruchus analis and Rhyzopertha dominic. The methanolic extract, n-hexane, DCM ethyl acetate and n-butanol showed 75, 85, 85, 65 and 5%phytotoxicity at the tested concentration of 500μg/mL respectively. The solvent fractions (DCM and ethyl acetate) were effective against F. solani (10%and 20%inhibition respectively). All the tested samples were devoid of cytotoxic and antibacterial effects. Conclusions:It was concluded that this plant can be practiced for control of weeds and insects.

  13. Molecular biology of thermosensory transduction in C. elegans.

    Science.gov (United States)

    Aoki, Ichiro; Mori, Ikue

    2015-10-01

    As the environmental temperature prominently influences diverse biological aspects of the animals, thermosensation and the subsequent information processing in the nervous system has attracted much attention in biology. Thermotaxis in the nematode Caenorhabditis elegans is an ideal behavioral paradigm by which to address the molecular mechanism underlying thermosensory transduction. Molecular genetic analysis in combination with other physiological and behavioral studies revealed that sensation of ambient temperature is mediated mainly by cyclic guanosine monophosphate (cGMP) signaling in thermosensory neurons. The information of the previously perceived temperature is also stored within the thermosensory neurons, and the consequence of the comparison between the past and the present temperature is conveyed to the downstream interneurons to further regulate the motor-circuits that encode the locomotion.

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

    Science.gov (United States)

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

    2013-03-01

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

  15. 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.

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

    Science.gov (United States)

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

    2016-09-01

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

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

    Science.gov (United States)

    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.

  18. The epipharyngeal sensilla of the damselfly Ischnura elegans (Odonata, Coenagrionidae).

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    Rebora, Manuela; Gaino, Elda; Piersanti, Silvana

    2014-11-01

    The knowledge on Odonata adult mouthparts sensilla is scanty and, notwithstanding the epipharynx in the labrum is considered an organ of taste, no ultrastructural investigation has been performed so far on this structure in Odonata. The labrum of the adult of the damselfly Ischnura elegans (Odonata, Coenagrionidae) shows on its ventral side the epipharynx with sensilla represented by articulated hairs and by small pegs located at the apex of slightly raised domes. Under scanning and transmission electron microscope, the articulated hairs, with a well developed socket and tubular body, have the typical structure of bristles, the most common type of insect mechanoreceptors, usually responding to direct touch; the pegs, showing an apical pore together with a variable number of sensory neurons (from two to five), the outer dendritic segments of which show a dendrite sheath stopping along their length, have features typical of contact chemoreceptors.

  19. 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.

  20. IgCAMs redundantly control axon navigation in Caenorhabditis elegans

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    Voltmer-Irsch Susanne

    2009-04-01

    Full Text Available Abstract Background Cell adhesion molecules of the immunoglobulin superfamily (IgCAMs form one of the largest and most diverse families of adhesion molecules and receptors in the nervous system. Many members of this family mediate contact and communication among neurons during development. The Caenorhabditis elegans genome contains a comparatively small number of IgCAMs, most of which are evolutionarily conserved and found across all animal phyla. Only some of these have been functionally characterized so far. Results We systematically analyzed previously uncharacterized IgCAMs in C. elegans. Green fluorescent protein reporter constructs of 12 IgCAMs revealed that expression generally is not confined to a single tissue and that all tissues express at least one of the IgCAMs. Most IgCAMs were expressed in neurons. Within the nervous system significant overlap in expression was found in central components of the motor circuit, in particular the command interneurons, ventral cord motoneurons as well as motoneurons innervating head muscles. Sensory neurons are underrepresented among the cells expressing these IgCAMs. We isolated mutations for eight of the genes showing neuronal expression. Phenotypic analysis of single mutants revealed limited neuronal defects, in particular axon navigation defects in some of the mutants. Systematic genetic interaction studies uncovered two cases of functional overlap among three and four genes, respectively. A strain combining mutations in all eight genes is viable and shows no additional defects in the neurons that were analyzed, suggesting that genetic interactions among those genes are limited. Conclusion Genetic interactions involving multiple IgCAMs affecting axon outgrowth demonstrate functional overlap among IgCAMs during nervous system development.

  1. Malate and fumarate extend lifespan in Caenorhabditis elegans.

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    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.

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

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    Kumar, Sandeep; Dietrich, Nicholas; Kornfeld, Kerry

    2016-02-01

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

  3. 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

  4. The mystery of C. elegans aging: an emerging role for fat. Distant parallels between C. elegans aging and metabolic syndrome?

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    Ackerman, Daniel; Gems, David

    2012-06-01

    New C. elegans studies imply that lipases and lipid desaturases can mediate signaling effects on aging. But why might fat homeostasis be critical to aging? Could problems with fat handling compromise health in nematodes as they do in mammals? The study of signaling pathways that control longevity could provide the key to one of the great unsolved mysteries of biology: the mechanism of aging. But as our view of the regulatory pathways that control aging grows ever clearer, the nature of aging itself has, if anything, grown more obscure. In particular, focused investigations of the oxidative damage theory have raised questions about an old assumption: that a fundamental cause of aging is accumulation of molecular damage. Could fat dyshomeostasis instead be critical?

  5. Expression of mammalian GPCRs in C. elegans generates novel behavioural responses to human ligands

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    Jansen Gert

    2006-07-01

    Full Text Available Abstract Background G-protein-coupled receptors (GPCRs play a crucial role in many biological processes and represent a major class of drug targets. However, purification of GPCRs for biochemical study is difficult and current methods of studying receptor-ligand interactions involve in vitro systems. Caenorhabditis elegans is a soil-dwelling, bacteria-feeding nematode that uses GPCRs expressed in chemosensory neurons to detect bacteria and environmental compounds, making this an ideal system for studying in vivo GPCR-ligand interactions. We sought to test this by functionally expressing two medically important mammalian GPCRs, somatostatin receptor 2 (Sstr2 and chemokine receptor 5 (CCR5 in the gustatory neurons of C. elegans. Results Expression of Sstr2 and CCR5 in gustatory neurons allow C. elegans to specifically detect and respond to somatostatin and MIP-1α respectively in a robust avoidance assay. We demonstrate that mammalian heterologous GPCRs can signal via different endogenous Gα subunits in C. elegans, depending on which cells it is expressed in. Furthermore, pre-exposure of GPCR transgenic animals to its ligand leads to receptor desensitisation and behavioural adaptation to subsequent ligand exposure, providing further evidence of integration of the mammalian GPCRs into the C. elegans sensory signalling machinery. In structure-function studies using a panel of somatostatin-14 analogues, we identified key residues involved in the interaction of somatostatin-14 with Sstr2. Conclusion Our results illustrate a remarkable evolutionary plasticity in interactions between mammalian GPCRs and C. elegans signalling machinery, spanning 800 million years of evolution. This in vivo system, which imparts novel avoidance behaviour on C. elegans, thus provides a simple means of studying and screening interaction of GPCRs with extracellular agonists, antagonists and intracellular binding partners.

  6. 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

  7. OrthoList: A Compendium of C. elegans Genes with Human Orthologs

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    Shaye, Daniel D.; Greenwald, Iva

    2011-01-01

    Background C. elegans is an important model for genetic studies relevant to human biology and disease. We sought to assess the orthology between C. elegans and human genes to understand better the relationship between their genomes and to generate a compelling list of candidates to streamline RNAi-based screens in this model. Results We performed a meta-analysis of results from four orthology prediction programs and generated a compendium, “OrthoList”, containing 7,663 C. elegans protein-coding genes. Various assessments indicate that OrthoList has extensive coverage with low false-positive and false-negative rates. Part of this evaluation examined the conservation of components of the receptor tyrosine kinase, Notch, Wnt, TGF-ß and insulin signaling pathways, and led us to update compendia of conserved C. elegans kinases, nuclear hormone receptors, F-box proteins, and transcription factors. Comparison with two published genome-wide RNAi screens indicated that virtually all of the conserved hits would have been obtained had just the OrthoList set (∼38% of the genome) been targeted. We compiled Ortholist by InterPro domains and Gene Ontology annotation, making it easy to identify C. elegans orthologs of human disease genes for potential functional analysis. Conclusions We anticipate that OrthoList will be of considerable utility to C. elegans researchers for streamlining RNAi screens, by focusing on genes with apparent human orthologs, thus reducing screening effort by ∼60%. Moreover, we find that OrthoList provides a useful basis for annotating orthology and reveals more C. elegans orthologs of human genes in various functional groups, such as transcription factors, than previously described. PMID:21647448

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

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    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.

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

    Science.gov (United States)

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

    2005-08-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    Science.gov (United States)

    Hirotsu, Takaaki; Sonoda, Hideto; Uozumi, Takayuki; Shinden, Yoshiaki; Mimori, Koshi; Maehara, Yoshihiko; Ueda, Naoko; Hamakawa, Masayuki

    2015-01-01

    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.

  13. 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.

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

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    Juozaityte, Vaida; Pladevall-Morera, David; Podolska, Agnieszka; Nørgaard, Steffen; Pocock, Roger

    2017-01-01

    Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans. Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show that ETS-5 acts to promote roaming and inhibit quiescence by setting the internal “satiety quotient” through fat regulation. Acting from the ASG and BAG sensory neurons, we show that ETS-5 functions in a complex network with serotonergic and neuropeptide signaling pathways to control food-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms. PMID:28193866

  15. Splicing of a C. elegans myosin pre-mRNA in a human nuclear extract

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    Ogg, S.C.; Anderson, P.; Wickens, M.P. (Univ. of Wisconsin, Madison (USA))

    1990-01-11

    Splicing of mammalian introns requires that the intron possess at least 80 nucleotides. This length requirement presumably reflects the constraints of accommodating multiple snRNPs simultaneously in the same intro. In the free-living nematode, C. elegans, introns typically are 45 to 55 nucleotides in length. In this report, the authors determine whether C. elegans introns can obviate the mammalian length requirement by virtue of their structure or sequence. They demonstrate that a 53 nucleotide intron from the unc-54 gene of C. elegans does not undergo splicing in a mammalian (HeLa) nuclear extract. However, insertion of 31 nucleotides of foreign, prokaryotic sequence into the same intron results in efficient splicing. The observed splicing proceeds by the same two-step mechanism observed with mammalian introns, and exploits the same 3{prime} and 5{prime} sites as are used in C. elegans. The branch point used lies in the inserted sequences. They conclude that C. elegans splicing components are either fewer in number or smaller than their mammalian counterparts.

  16. A conserved upstream motif orchestrates autonomous, germline-enriched expression of Caenorhabditis elegans piRNAs.

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    Allison C Billi

    Full Text Available Piwi-interacting RNAs (piRNAs fulfill a critical, conserved role in defending the genome against foreign genetic elements. In many organisms, piRNAs appear to be derived from processing of a long, polycistronic RNA precursor. Here, we establish that each Caenorhabditis elegans piRNA represents a tiny, autonomous transcriptional unit. Remarkably, the minimal C. elegans piRNA cassette requires only a 21 nucleotide (nt piRNA sequence and an ∼50 nt upstream motif with limited genomic context for expression. Combining computational analyses with a novel, in vivo transgenic system, we demonstrate that this upstream motif is necessary for independent expression of a germline-enriched, Piwi-dependent piRNA. We further show that a single nucleotide position within this motif directs differential germline enrichment. Accordingly, over 70% of C. elegans piRNAs are selectively expressed in male or female germline, and comparison of the genes they target suggests that these two populations have evolved independently. Together, our results indicate that C. elegans piRNA upstream motifs act as independent promoters to specify which sequences are expressed as piRNAs, how abundantly they are expressed, and in what germline. As the genome encodes well over 15,000 unique piRNA sequences, our study reveals that the number of transcriptional units encoding piRNAs rivals the number of mRNA coding genes in the C. elegans genome.

  17. Deletion of thioredoxin reductase and effects of selenite and selenate toxicity in Caenorhabditis elegans.

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    Christopher J Boehler

    Full Text Available Thioredoxin reductase-1 (TRXR-1 is the sole selenoprotein in C. elegans, and selenite is a substrate for thioredoxin reductase, so TRXR-1 may play a role in metabolism of selenium (Se to toxic forms. To study the role of TRXR in Se toxicity, we cultured C. elegans with deletions of trxr-1, trxr-2, and both in axenic media with increasing concentrations of inorganic Se. Wild-type C. elegans cultured for 12 days in Se-deficient axenic media grow and reproduce equivalent to Se-supplemented media. Supplementation with 0-2 mM Se as selenite results in inverse, sigmoidal response curves with an LC50 of 0.20 mM Se, due to impaired growth rather than reproduction. Deletion of trxr-1, trxr-2 or both does not modulate growth or Se toxicity in C. elegans grown axenically, and (75Se labeling showed that TRXR-1 arises from the trxr-1 gene and not from bacterial genes. Se response curves for selenide (LC50 0.23 mM Se were identical to selenite, but selenate was 1/4(th as toxic (LC50 0.95 mM Se as selenite and not modulated by TRXR deletion. These nutritional and genetic studies in axenic media show that Se and TRXR are not essential for C. elegans, and that TRXR alone is not essential for metabolism of inorganic Se to toxic species.

  18. 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.

  19. A conserved function of C. elegans CASY-1 calsyntenin in associative learning.

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    Frédéric J Hoerndli

    Full Text Available BACKGROUND: Whole-genome association studies in humans have enabled the unbiased discovery of new genes associated with human memory performance. However, such studies do not allow for a functional or causal testing of newly identified candidate genes. Since polymorphisms in Calsyntenin 2 (CLSTN2 showed a significant association with episodic memory performance in humans, we tested the C. elegans CLSTN2 ortholog CASY-1 for possible functions in the associative behavior of C. elegans. METHODOLOGY/PRINCIPAL FINDINGS: Using three different associative learning paradigms and functional rescue experiments, we show that CASY-1 plays an important role during associative learning in C. elegans. Furthermore, neuronal expression of human CLSTN2 in C. elegans rescues the learning defects of casy-1 mutants. Finally, genetic interaction studies and neuron-specific expression experiments suggest that CASY-1 may regulate AMPA-like GLR-1 glutamate receptor signaling. CONCLUSION/SIGNIFICANCE: Our experiments demonstrate a remarkable conservation of the molecular function of Calsyntenins between nematodes and humans and point at a role of C. elegans casy-1 in regulating a glutamate receptor signaling pathway.

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

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    Park, Sojin; Choi, Seoyun; Ahn, Byungchan

    2016-03-01

    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.

  1. Advanced behavioral analyses show that the presence of food causes subtle changes in C. elegans movement

    Directory of Open Access Journals (Sweden)

    Nicholas eAngstman

    2016-03-01

    Full Text Available As a widely used and studied model organism, C. elegans worms offer the ability to investigate implications of behavioral change. Although investigation of C. elegans behavioral traits has been shown, analysis is often narrowed down to measurements based off a single point, and thus cannot pick up on subtle behavioral and morphological changes. In the present study videos were captured of four different C. elegans strains grown in liquid cultures and transferred to NGM-agar plates with an E. coli lawn or with no lawn. Using an advanced software, WormLab, the full skeleton and outline of worms were tracked to determine whether the presence of food affects behavioral traits. In all seven investigated parameters, statistically significant differences were found in worm behavior between those moving on NGM-agar plates with an E. coli lawn and NGM-agar plates with no lawn. Furthermore, multiple test groups showed differences in interaction between variables as the parameters that significantly correlated statistically with speed of locomotion varied. In the present study, we demonstrate the validity of a model to analyze C. elegans behavior beyond simple speed of locomotion. The need to account for a nested design while performing statistical analyses in similar studies is also demonstrated. With extended analyses, C. elegans behavioral change can be investigated with greater sensitivity, which could have wide utility in fields such as, but not limited to, toxicology, drug discovery, and RNAi screening.

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

    Science.gov (United States)

    Koopman, Mandy; Michels, Helen; Dancy, Beverley M; Kamble, Rashmi; Mouchiroud, Laurent; Auwerx, Johan; Nollen, Ellen A A; Houtkooper, Riekelt H

    2016-10-01

    Mitochondrial dysfunction is at the core of many diseases ranging from inherited metabolic diseases to common conditions that are associated with aging. Although associations between aging and mitochondrial function have been identified using mammalian models, much of the mechanistic insight has emerged from Caenorhabditis elegans. Mitochondrial respiration is recognized as an indicator of mitochondrial health. The Seahorse XF96 respirometer represents the state-of-the-art platform for assessing respiration in cells, and we adapted the technique for applications involving C. elegans. Here we provide a detailed protocol to optimize and measure respiration in C. elegans with the XF96 respirometer, including the interpretation of parameters and results. The protocol takes ∼2 d to complete, excluding the time spent culturing C. elegans, and it includes (i) the preparation of C. elegans samples, (ii) selection and loading of compounds to be injected, (iii) preparation and execution of a run with the XF96 respirometer and (iv) postexperimental data analysis, including normalization. In addition, we compare our XF96 application with other existing techniques, including the eight-well Seahorse XFp. The main benefits of the XF96 include the limited number of worms required and the high throughput capacity due to the 96-well format.

  3. Natural polymorphisms in C. elegans HECW-1 E3 ligase affect pathogen avoidance behaviour.

    Science.gov (United States)

    Chang, Howard C; Paek, Jennifer; Kim, Dennis H

    2011-11-16

    Heritable variation in behavioural traits generally has a complex genetic basis, and thus naturally occurring polymorphisms that influence behaviour have been defined only in rare instances. The isolation of wild strains of Caenorhabditis elegans has facilitated the study of natural genetic variation in this species and provided insights into its diverse microbial ecology. C. elegans responds to bacterial infection with conserved innate immune responses and, although lacking the immunological memory of vertebrate adaptive immunity, shows an aversive learning response to pathogenic bacteria. Here, we report the molecular characterization of naturally occurring coding polymorphisms in a C. elegans gene encoding a conserved HECT domain-containing E3 ubiquitin ligase, HECW-1. We show that two distinct polymorphisms in neighbouring residues of HECW-1 each affect C. elegans behavioural avoidance of a lawn of Pseudomonas aeruginosa. Neuron-specific rescue and ablation experiments and genetic interaction analysis indicate that HECW-1 functions in a pair of sensory neurons to inhibit P. aeruginosa lawn avoidance behaviour through inhibition of the neuropeptide receptor NPR-1 (ref. 10), which we have previously shown promotes P. aeruginosa lawn avoidance behaviour. Our data establish a molecular basis for natural variation in a C. elegans behaviour that may undergo adaptive changes in response to microbial pathogens.

  4. The phytochemical glaucarubinone promotes mitochondrial metabolism, reduces body fat, and extends lifespan of Caenorhabditis elegans.

    Science.gov (United States)

    Zarse, K; Bossecker, A; Müller-Kuhrt, L; Siems, K; Hernandez, M A; Berendsohn, W G; Birringer, M; Ristow, M

    2011-04-01

    Naturally occurring compounds that promote energy expenditure and delay aging in model organisms may be of significant interest, since these substances potentially provide pharmaceutical approaches to tackle obesity and promote healthy lifespan in humans. We aimed to test whether pharmaceutical concentrations of glaucarubinone, a cytotoxic and antimalarial quassinoid known from different species of the plant family Simaroubaceae, are capable of affecting metabolism and/or extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Adult C. elegans roundworms, maintained on agar plates, were fed with E. coli strain OP50 bacteria, and glaucarubinone was applied to the agar to test (i) whether it alters respiration rates and mitochondrial activity, (ii) whether it affects body fat content, and (iii) whether it may promote longevity by quantifying survival in the presence and absence of the compound. We have found that glaucarubinone induces oxygen consumption and reduces body fat content of C. elegans. Moreover and consistent with the concept of mitohormesis, glaucarubinone extends C. elegans lifespan when applied at a concentration of 1 or 10 nanomolar. Taken together, glaucarubinone is capable of reducing body fat and promoting longevity in C. elegans, tentatively suggesting that this compound may promote metabolic health and lifespan in mammals and possibly humans.

  5. Lipid-lowering fibrates extend C. elegans lifespan in a NHR-49/PPARalpha-dependent manner.

    Science.gov (United States)

    Brandstädt, Sven; Schmeisser, Kathrin; Zarse, Kim; Ristow, Michael

    2013-04-01

    Compounds that delay aging in model organisms may be of significant interest to anti-aging medicine, since these substances potentially provide pharmaceutical approaches to promote healthy lifespan in humans. We here aimed to test whether pharmaceutical concentrations of three fibrates, pharmacologically established serum lipid-lowering drugs and ligands of the nuclear receptor PPARalpha in mammals, are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Adult C. elegans (wild-type N2 as well as two nhr-49-deficient strains, RB1716 and VC870) were maintained on agar plates and were fed E. coli strain OP50 bacteria. Bezafibrate, clofibrate, and fenofibrate were applied to the agar, respectively, to test whether they may promote longevity by quantifying survival in the presence and absence of the respective compounds. All three fibrates extended C. elegans N2 lifespan when applied at a concentration of 10 micromolar. Bezafibrate additionally extended C. elegans N2 lifespan at concentrations of 1 micromolar and 0.1 micromolar. In strains deficient for nhr-49, a functional orthologue of the mammalian peroxisome proliferator-activated receptor alpha (PPARalpha), all three compounds were incapable of extending lifespan. Taken together, fibrates promote C. elegans longevity in an NHR-49-dependent manner possibly by promoting mitohormesis and suggesting that these compounds may promote lifespan also in mammals.

  6. Lactobacillus salivarius strain FDB89 induced longevity in Caenorhabditis elegans by dietary restriction.

    Science.gov (United States)

    Zhao, Yang; Zhao, Liang; Zheng, Xiaonan; Fu, Tianjiao; Guo, Huiyuan; Ren, Fazheng

    2013-04-01

    In this study, we utilized the nematode Caenorhabditis elegans to assess potential life-expanding effect of Lactobacillus salivarius strain FDB89 (FDB89) isolated from feces of centenarians in Bama County (Guangxi, China). This study showed that feeding FDB89 extended the mean life span in C. elegans by up to 11.9% compared to that of control nematodes. The reduced reproductive capacities, pharyngeal pumping rate, growth, and increased superoxide dismutase (SOD) activity and XTT reduction capacity were also observed in FDB89 feeding worms. To probe the anti-aging mechanism further, we incorporated a food gradient feeding assay and assayed the life span of eat-2 mutant. The results demonstrated that the maximal life span of C. elegans fed on FDB89 was achieved at the concentration of 1.0 mg bacterial cells/plate, which was 10-fold greater than that of C. elegans fed on E. coli OP50 (0.1 mg bacterial cells/plate). However, feeding FDB89 could not further extend the life span of eat-2 mutant. These results indicated that FDB89 modulated the longevity of C. elegans in a dietary restriction-dependent manner and expanded the understanding of anti-aging effect of probiotics.

  7. Characterization and expression of calmodulin gene during larval settlement and metamorphosis of the polychaete Hydroides elegans

    KAUST Repository

    Chen, Zhangfan

    2012-08-01

    The polychaete . Hydroides elegans (Serpulidae, Lophotrochozoa) is a problematic marine fouling organism in most tropical and subtropical coastal environment. Competent larvae of . H. elegans undergo the transition from the swimming larval stage to the sessile juvenile stage with substantial morphological, physiological, and behavior changes. This transition is often referred to as larval settlement and metamorphosis. In this study, we examined the possible involvement of calmodulin (CaM) - a multifunctional calcium metabolism regulator, in the larval settlement and metamorphosis of . H. elegans. A full-length . CaM cDNA was successfully cloned from . H. elegans (. He-CaM) and it contained an open reading frame of 450. bp, encoding 149 amino acid residues. It was highly expressed in 12. h post-metamorphic juveniles, and remained high in adults. . In situ hybridization conducted in competent larvae and juveniles revealed that . He-CaM gene was continuously expressed in the putative growth zones, branchial rudiments, and collar region, suggesting that . He-CaM might be involved in tissue differentiation and development. Our subsequent bioassay revealed that the CaM inhibitor W7 could effectively inhibit larval settlement and metamorphosis, and cause some morphological defects of unsettled larvae. In conclusion, our results revealed that CaM has important functions in the larval settlement and metamorphosis of . H. elegans. © 2012 Elsevier Inc..

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

    Science.gov (United States)

    Li, Yunhui; Zhang, Minhui; Chen, Pan; Liu, Ran; Liang, Geyu; Yin, Lihong; Pu, Yuepu

    2015-09-22

    Little is known about the effect on spermiogenesis induced by microcystin-leucine arginine (MC-LR), even though such data are very important to better elucidate reproductive health. In the current work, with the aid of nematode Caenorhabditis elegans (C. elegans) as an animal model, we investigated the defects on spermiogenesis induced by MC-LR. Our results showed that MC-LR exposure induced sperm morphology abnormality and caused severe defects of sperm activation, trans-activation, sperm behavior and competition. Additionally, the expression levels of spe-15 were significantly decreased in C. elegans exposed to MC-LR lower than 16.0 μg/L, while the expression levels of spe-10 and fer-1 could be significantly lowered in C. elegans even exposed to 1.0 μg/L of MC-LR. Therefore, the present study reveals that MC-LR can induce adverse effects on spermiogenesis, and those defects of sperm functions may be induced by the decreases of spe-10, spe-15 and fer-1 gene expressions in C. elegans.

  9. Advanced Behavioral Analyses Show that the Presence of Food Causes Subtle Changes in C. elegans Movement.

    Science.gov (United States)

    Angstman, Nicholas B; Frank, Hans-Georg; Schmitz, Christoph

    2016-01-01

    As a widely used and studied model organism, Caenorhabditis elegans worms offer the ability to investigate implications of behavioral change. Although, investigation of C. elegans behavioral traits has been shown, analysis is often narrowed down to measurements based off a single point, and thus cannot pick up on subtle behavioral and morphological changes. In the present study videos were captured of four different C. elegans strains grown in liquid cultures and transferred to NGM-agar plates with an E. coli lawn or with no lawn. Using an advanced software, WormLab, the full skeleton and outline of worms were tracked to determine whether the presence of food affects behavioral traits. In all seven investigated parameters, statistically significant differences were found in worm behavior between those moving on NGM-agar plates with an E. coli lawn and NGM-agar plates with no lawn. Furthermore, multiple test groups showed differences in interaction between variables as the parameters that significantly correlated statistically with speed of locomotion varied. In the present study, we demonstrate the validity of a model to analyze C. elegans behavior beyond simple speed of locomotion. The need to account for a nested design while performing statistical analyses in similar studies is also demonstrated. With extended analyses, C. elegans behavioral change can be investigated with greater sensitivity, which could have wide utility in fields such as, but not limited to, toxicology, drug discovery, and RNAi screening.

  10. Sinoorbital mucormycosis due to Apophysomyces elegans in immunocompetent individuals--an increasing trend.

    Science.gov (United States)

    Suryanarayan Rao, Sridhara; Panda, Naresh K; Pragache, Gilbert; Chakrabarti, Arunaloke; Saravanan, K

    2006-01-01

    Mucormycosis is a fatal infection of the immunocompromised individuals. Apophysomyces elegans is an unusual pathogen causing mucormycosis. It is unusual to affect the healthy individuals. We report 5 such cases of infection caused by A elegans in immunocompetent individuals. Retrospective case review conducted at a tertiary referral center. From 1999 to 2004, 5 cases of mucormycosis caused by A elegans were managed in otherwise healthy patients. All of them were treated with surgery. Clinical presentation, imaging studies, mycological findings, operative findings at surgery, and postoperative results were evaluated. A review of literature about mucormycosis caused by A elegans infecting otherwise healthy patients in orbit, nose, and paranasal sinuses has been done. All had no previous history of trauma or any invasive procedure. All of them underwent surgical treatment. Histopathological examination showed broad, sparsely aseptate, thin-walled hyphae and angioinvasion with thrombosis. Fungal culture revealed A elegans. Mucormycosis must be considered in the differential diagnosis of any severe acute headache, sinusitis, or orbital cellulites not only in the immunocompromised patients but also in the absence of any underlying disease. Successful treatment requires early debridement and systemic antifungal treatment with injection of amphotericin B.

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

    Directory of Open Access Journals (Sweden)

    Sihui Zhang

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  13. miR-124/ATF-6, a novel lifespan extension pathway of Astragalus polysaccharide in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Ning; Liu, Jing; Xie, Fang; Gao, Xu; Ye, Jian-Han; Sun, Lu-Yao; Wei, Ran; Ai, Jing

    2015-02-01

    MicroRNAs (miRNAs), especially evolutionarily conserved miRNAs play critical roles in regulating various biological process. However, the functions of conserved miRNAs in longevity are still largely unknown. Astragalus polysaccharide (APS) was recently shown to extend lifespan of Caenorhabditis elegans, but its molecular mechanisms have not been fully understood. In the present study, we characterize that microRNA mediated a novel longevity pathway of APS in C. elegans. We found that APS markedly extended the lifespan of C. elegans at the second and the fourth stages. A highly conserved miRNA miR-124 was significantly upregulated in APS-treated C. elegans. Overexpression miR-124 caused the lifespan extension of C. elegans and vice versa, indicating miR-124 regulates the longevity of C. elegans. Using luciferase assay, atf-6 was established as a target gene of miR-124 which acting on three binding sites at atf-6 3'UTR. Consistently, agomir-cel-miR-124 was also shown to inhibit ATF-6 expression in C. elegans. APS-treated C. elegans showed the down-regulation of atf-6 at protein level. Furthermore, the knockdown of atf-6 by RNAi extended the lifespan of C. elegans, indicating atf-6 regulated by miR-124 contributes to lifespan extension. Taken together, miR-124 regulating ATF-6 is a new potential longevity signal pathway, which underlies the lifespan-extending effects of APS in C. elegans. © 2014 Wiley Periodicals, Inc.

  14. The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length

    Science.gov (United States)

    Cook, Daniel E.; Zdraljevic, Stefan; Tanny, Robyn E.; Seo, Beomseok; Riccardi, David D.; Noble, Luke M.; Rockman, Matthew V.; Alkema, Mark J.; Braendle, Christian; Kammenga, Jan E.; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C.

    2016-01-01

    Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans. PMID:27449056

  15. Excision repair of UV radiation-induced DNA damage in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, P.S.; Hevelone, J.; Dwarakanath, V.; Mitchell, D.L. (Texas Christian Univ., Fort Worth (USA))

    1989-06-01

    Radioimmunoassays were used to monitor the removal of antibody-binding sites associated with the two major UV radiation-induced DNA photoproducts (cyclobutane dimers and (6-4) photoproducts). Unlike with cultured human cells, where (6-4) photoproducts are removed more rapidly than cyclobutane dimers, the kinetics of repair were similar for both lesions. Repair capacity in wild type diminished throughout development. The radioimmunoassays were also employed to confirm the absence of photoreactivation in C. elegans. In addition, three radiation-sensitive mutants (rad-1, rad-2, rad-7) displayed normal repair capacities. An excision defect was much more pronounced in larvae than embryos in the fourth mutant tested (rad-3). This correlates with the hypersensitivity pattern of this mutant and suggests that DNA repair may be developmentally regulated in C. elegans. The mechanism of DNA repair in C. elegans as well as the relationship between the repair of specific photoproducts and UV radiation sensitivity during development are discussed.

  16. The nephronophthisis-related gene ift-139 is required for ciliogenesis in Caenorhabditis elegans

    Science.gov (United States)

    Niwa, Shinsuke

    2016-01-01

    Defects in cilia cause a spectrum of diseases known as ciliopathies. Nephronophthisis, a ciliopathy, is the most common genetic cause of renal disease. Here, I cloned and analysed a nephronophthisis-related gene ift-139 in Caenorhabditis elegans. ift-139 was exclusively expressed in ciliated neurons in C. elegans. Genetic and cellular analyses suggest that ift-139 plays a role in retrograde intraflagellar transport and is required for cilia formation. A homologous point mutation that causes ciliopathy disrupted the function of ift-139 in C. elegans. ift-139 is an orthologue of human TTC21B, mutations in which are known to cause nephronophthisis 12 and short-rib thoracic dysplasia 4. These results suggest that ift-139 is evolutionarily conserved and fundamental to the formation of cilia. PMID:27515926

  17. Pharyngeal pumping continues after laser killing of the pharyngeal nervous system of C. elegans

    Energy Technology Data Exchange (ETDEWEB)

    Avery, L.; Horvitz, H.R. (Massachusetts Institute of Technology, Cambridge (USA))

    1989-10-01

    Using a laser microbeam to kill specific subsets of the pharyngeal nervous system of C. elegans, we found that feeding was accomplished by two separately controlled muscle motions, isthmus peristalsis and pumping. The single neuron M4 was necessary and sufficient for isthmus peristalsis. The MC neurons were necessary for normal stimulation of pumping in response to food, but pumping continued and was functional in MC- worms. The remaining 12 neuron types were also unnecessary for functional pumping. No operation we did, including destruction of the entire pharyngeal nervous system, abolished pumping altogether. When we killed all pharyngeal neurons except M4, the worms were viable and fertile, although retarded and starved. Since feeding is one of the few known essential actions controlled by the nervous system, we suggest that most of the C. elegans nervous system is dispensable in hermaphrodites under laboratory conditions. This may explain the ease with which nervous system mutants are isolated and handled in C. elegans.

  18. The Genetic Basis of Natural Variation in Caenorhabditis elegans Telomere Length.

    Science.gov (United States)

    Cook, Daniel E; Zdraljevic, Stefan; Tanny, Robyn E; Seo, Beomseok; Riccardi, David D; Noble, Luke M; Rockman, Matthew V; Alkema, Mark J; Braendle, Christian; Kammenga, Jan E; Wang, John; Kruglyak, Leonid; Félix, Marie-Anne; Lee, Junho; Andersen, Erik C

    2016-09-01

    Telomeres are involved in the maintenance of chromosomes and the prevention of genome instability. Despite this central importance, significant variation in telomere length has been observed in a variety of organisms. The genetic determinants of telomere-length variation and their effects on organismal fitness are largely unexplored. Here, we describe natural variation in telomere length across the Caenorhabditis elegans species. We identify a large-effect variant that contributes to differences in telomere length. The variant alters the conserved oligonucleotide/oligosaccharide-binding fold of protection of telomeres 2 (POT-2), a homolog of a human telomere-capping shelterin complex subunit. Mutations within this domain likely reduce the ability of POT-2 to bind telomeric DNA, thereby increasing telomere length. We find that telomere-length variation does not correlate with offspring production or longevity in C. elegans wild isolates, suggesting that naturally long telomeres play a limited role in modifying fitness phenotypes in C. elegans.

  19. The adiponectin receptor homologs in C. elegans promote energy utilization and homeostasis

    DEFF Research Database (Denmark)

    Svensson, Emma; Olsen, Louise Cathrine Braun; Mörck, Catarina;

    2011-01-01

    in the nematode C. elegans, named paqr-1, paqr-2 and paqr-3. These are differently expressed in the intestine (the main fat-storing tissue), hypodermis, muscles, neurons and secretory tissues, from which they could exert systemic effects. Analysis of mutants revealed that paqr-1 and -2 are novel metabolic...... regulators in C. elegans and that they act redundantly but independently from paqr-3. paqr-2 is the most important of the three paqr genes: mutants grow poorly, fail to adapt to growth at low temperature, and have a very high fat content with an abnormal enrichment in long (C20) poly-unsaturated fatty acids...... when combined with the paqr-1 mutation. paqr-2 mutants are also synthetic lethal with mutations in nhr-49, sbp-1 and fat-6, which are C. elegans homologs of nuclear hormone receptors, SREBP and FAT-6 (a Δ9 desaturase), respectively. Like paqr-2, paqr-1 is also synthetic lethal with sbp-1. Mutations...

  20. 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

    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...... alone resulted in a two- to threefold reduction in MRSA load. In conclusion, C. elegans can be used as a simple model to test synergy between DCX and TZ against MRSA. The previously demonstrated in vitro synergy can be reproduced in vivo....

  1. 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.

  2. 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

  3. Long-term imaging of Caenorhabditis elegans using nanoparticle-mediated immobilization.

    Directory of Open Access Journals (Sweden)

    Eric Kim

    Full Text Available One advantage of the nematode Caenorhabditis elegans as a model organism is its suitability for in vivo optical microscopy. Imaging C. elegans often requires animals to be immobilized to avoid movement-related artifacts. Immobilization has been performed by application of anesthetics or by introducing physical constraints using glue or specialized microfluidic devices. Here we present a method for immobilizing C. elegans using polystyrene nanoparticles and agarose pads. Our technique is technically simple, does not expose the worm to toxic substances, and allows recovery of animals. We evaluate the method and show that the polystyrene beads increase friction between the worm and agarose pad. We use our method to quantify calcium transients and long-term regrowth in single neurons following axotomy by a femtosecond laser.

  4. 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.

  5. In vitro variation in antibacterial activity plant extracts on Glaucium elegans and saffron (Crocus sativus

    Directory of Open Access Journals (Sweden)

    Ehsan Heidari Soureshjani

    2014-08-01

    Full Text Available The increase in antibiotic resistance has resulted in decreasing number active antimicrobial agents available to treat infections by multi-drug resistant (MDR bacteria. The aim of this study was to determine the antimicrobial activity of the extracts of Glaucium elegans and saffron (Crocus sativus onios plant species against Escherichia coli, Staphylococcus aureus, Salmonella enteritidis, Bacillus anthracis and Proteus by disc diffusion method. The methanol extract of G. elegans was found to have a significant antibacterial efficiency (p≤0.05 as compared to the methanol extract of onios plant. These finding pinpoint the efficiency of these extracts to inhibit microbial growth. The bactericidal activity described here represents an added safety value for G. elegans possesses the significant antibacterial activity.

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

    Science.gov (United States)

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

    2011-10-18

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

  7. Closing in on the C. elegans ORFeome by cloning TWINSCAN predictions

    DEFF Research Database (Denmark)

    Wei, Chaochun; Lamesch, Philippe; Arumugam, Manimozhiyan

    2005-01-01

    The genome of Caenorhabditis elegans was the first animal genome to be sequenced. Although considerable effort has been devoted to annotating it, the standard WormBase annotation contains thousands of predicted genes for which there is no cDNA or EST evidence. We hypothesized that a more complete...... experimental annotation could be obtained by creating a more accurate gene-prediction program and then amplifying and sequencing predicted genes. Our approach was to adapt the TWINSCAN gene prediction system to C. elegans and C. briggsae and to improve its splice site and intron-length models. The resulting...... be significantly increased by replacing its partially curated predicted genes with TWINSCAN predictions. The technology described in this study will continue to drive the C. elegans ORFeome toward completion and contribute to the annotation of the three Caenorhabditis species currently being sequenced. The results...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

  9. RNAi Interrogation of Dietary Modulation of Development, Metabolism, Behavior, and Aging in C. elegans.

    Science.gov (United States)

    Xiao, Rui; Chun, Lei; Ronan, Elizabeth A; Friedman, David I; Liu, Jianfeng; Xu, X Z Shawn

    2015-05-19

    Diet affects nearly every aspect of animal life such as development, metabolism, behavior, and aging, both directly by supplying nutrients and indirectly through gut microbiota. C. elegans feeds on bacteria, and like other animals, different bacterial diets induce distinct dietary responses in the worm. However, the lack of certain critical tools hampers the use of worms as a model for dietary signaling. Here, we genetically engineered the bacterial strain OP50, the standard laboratory diet for C. elegans, making it compatible for dsRNA production and delivery. Using this RNAi-compatible OP50 strain and the other bacterial strain HT115, we feed worms different diets while delivering RNAi to interrogate the genetic basis underlying diet-dependent differential modulation of development, metabolism, behavior, and aging. We show by RNAi that neuroendocrine and mTOR pathways are involved in mediating differential dietary responses. This genetic tool greatly facilitates the use of C. elegans as a model for dietary signaling.

  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. 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

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

    Science.gov (United States)

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

    2014-03-01

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

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

    Science.gov (United States)

    Hammell, Christopher M; Hannon, Gregory J

    2016-01-04

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

  14. Existence of four acetylcholinesterase genes in the nematodes Caenorhabditis elegans and Caenorhabditis briggsae.

    Science.gov (United States)

    Grauso, M; Culetto, E; Combes, D; Fedon, Y; Toutant, J P; Arpagaus, M

    1998-03-13

    Three genes, ace-1, ace-2 and ace-3, respectively located on chromosomes X, I and II, were reported to encode acetylcholinesterases (AChEs) of classes A, B and C in the nematode Caenorhabditis elegans. We have previously cloned and sequenced ace-1 in the two related species C. elegans and C. briggsae. We report here partial sequences of ace-2 (encoding class B) and of two other ace sequences located in close proximity on chromosome II in C. elegans and C. briggsae. These two sequences are provisionally named ace-x and ace-y, because it is not possible at the moment to establish which of these two genes corresponds to ace-3. Ace-x and ace-y are transcribed in vivo as shown by RT-PCR and they are likely to be included in a single operon.

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

    Directory of Open Access Journals (Sweden)

    Ebany J. Martinez-Finley

    2011-01-01

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

  16. The intersection of aging, longevity pathways, and learning & memory in C. elegans

    Directory of Open Access Journals (Sweden)

    Geneva Marie Stein

    2012-11-01

    Full Text Available Our understanding of the molecular and genetic regulation of aging and longevity has been greatly augmented through studies using the small model system, C. elegans. It is important to test whether mutations that result in a longer life span also extend the health span of the organism, rather than simply prolonging an aged state. C. elegans can learn and remember both associated and non-associated stimuli, and many of these learning and memory paradigms are subject to regulation by longevity pathways. One of the more distressing results of aging is cognitive decline, and while no gross physical defects in C. elegans sensory neurons have been identified, the organism does lose the ability to perform both simple and complex learned behaviors with age. Here we review what is known about the effects of longevity pathways and the decline of these complex learned behaviors with age, and we highlight outstanding questions in the field.

  17. Using C. elegans to screen for targets of ethanol and behavior-altering drugs

    Directory of Open Access Journals (Sweden)

    Davies Andrew G.

    2004-01-01

    Full Text Available Caenorhabditis elegans is an attractive model system for determining the targets of neuroactive compounds. Genetic screens in C. elegans provide a relatively unbiased approach to the identification of genes that are essential for behavioral effects of drugs and neuroactive compounds such as alcohol. Much work in vertebrate systems has identified multiple potential targets of ethanol but which, if any, of those candidates are responsible for the behavioral effects of alcohol is uncertain. Here we provide detailed methodology for a genetic screen for mutants of C. elegans that are resistant to the depressive effects of ethanol on locomotion and for the subsequent behavioral analysis of those mutants. The methods we describe should also be applicable for use in screening for mutants that are resistant or hypersensitive to many neuroactive compounds and for identifying the molecular targets or biochemical pathways mediating drug responses.

  18. 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...

  19. Baccoside A suppresses epileptic-like seizure/convulsion in Caenorhabditis elegans.

    Science.gov (United States)

    Pandey, Rakesh; Gupta, Shipra; Tandon, Sudeep; Wolkenhauer, Olaf; Vera, Julio; Gupta, Shailendra K

    2010-09-01

    The 1 mm long Caenorhabditis elegans is one of the prime research tools to study different human neurodegenerative diseases. We have considered the case in which increase in the surrounding temperature of this multicellular model leads to abnormal bursts of neuronal cells that can be linked to seizure or convulsion. The induction of such seizure/convulsion mechanism was done by gradually increasing the temperature with 1x buffer (100 mM NaCl, 50 mM MgCl(2)) in adult C. elegans. In the present experiment it is demonstrated that Baccoside A can significantly reduce the seizure/convulsion in C. elegans at higher temperatures (26-28+/-1 degrees C). Furthermore, in T-type Ca(2+) channel cca-1 mutant worms, no convulsion was recorded. Our experimental results suggest that plant molecules from Bacopa monnieri may be useful in suppressing the seizure/convulsion in worms.

  20. Resolving coiled shapes reveals new reorientation behaviors in C. elegans

    Science.gov (United States)

    Broekmans, Onno D; Rodgers, Jarlath B; Ryu, William S; Stephens, Greg J

    2016-01-01

    We exploit the reduced space of C. elegans postures to develop a novel tracking algorithm which captures both simple shapes and also self-occluding coils, an important, yet unexplored, component of 2D worm behavior. We apply our algorithm to show that visually complex, coiled sequences are a superposition of two simpler patterns: the body wave dynamics and a head-curvature pulse. We demonstrate the precise Ω-turn dynamics of an escape response and uncover a surprising new dichotomy in spontaneous, large-amplitude coils; deep reorientations occur not only through classical Ω-shaped postures but also through larger postural excitations which we label here as δ-turns. We find that omega and delta turns occur independently, suggesting a distinct triggering mechanism, and are the serpentine analog of a random left-right step. Finally, we show that omega and delta turns occur with approximately equal rates and adapt to food-free conditions on a similar timescale, a simple strategy to avoid navigational bias. DOI: http://dx.doi.org/10.7554/eLife.17227.001 PMID:27644113

  1. Dynamic range in the C. elegans brain network

    Science.gov (United States)

    Antonopoulos, Chris G.

    2016-01-01

    We study external electrical perturbations and their responses in the brain dynamic network of the Caenorhabditis elegans soil worm, given by the connectome of its large somatic nervous system. Our analysis is inspired by a realistic experiment where one stimulates externally specific parts of the brain and studies the persistent neural activity triggered in other cortical regions. In this work, we perturb groups of neurons that form communities, identified by the walktrap community detection method, by trains of stereotypical electrical Poissonian impulses and study the propagation of neural activity to other communities by measuring the corresponding dynamic ranges and Steven law exponents. We show that when one perturbs specific communities, keeping the rest unperturbed, the external stimulations are able to propagate to some of them but not to all. There are also perturbations that do not trigger any response. We found that this depends on the initially perturbed community. Finally, we relate our findings for the former cases with low neural synchronization, self-criticality, and large information flow capacity, and interpret them as the ability of the brain network to respond to external perturbations when it works at criticality and its information flow capacity becomes maximal.

  2. The assembly of C. elegans lamins into macroscopic fibers.

    Science.gov (United States)

    Zingerman-Koladko, Irena; Khayat, Maayan; Harapin, Jan; Shoseyov, Oded; Gruenbaum, Yosef; Salman, Ahmad; Medalia, Ohad; Ben-Harush, Kfir

    2016-10-01

    Intermediate filament (IF) proteins are known mainly by their propensity to form viscoelastic filamentous networks within cells. In addition, IF-proteins are essential parts of various biological materials, such as horn and hagfish slime threads, which exhibit a range of mechanical properties from hard to elastic. These properties and their self-assembly nature made IF-proteins attractive building blocks for biomimetic and biological materials in diverse applications. Here we show that a type V IF-protein, the Caenorhabditis elegans nuclear lamin (Ce-lamin), is a promising building block for protein-based fibers. Electron cryo-tomography of vitrified sections enabled us to depict the higher ordered assembly of the Ce-lamin into macroscopic fibers through the creation of paracrystalline fibers, which are prominent in vitro structures of lamins. The lamin fibers respond to tensile force as other IF-protein-based fibers, i.e., hagfish slime threads, and possess unique mechanical properties that may potentially be used in certain applications. The self-assembly nature of lamin proteins into a filamentous structure, which is further assembled into a complex network, can be easily modulated. This knowledge may lead to a better understanding of the relationship in IF-proteins-based fibers and materials, between their hierarchical structures and their mechanical properties.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-04-01

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

  4. Caenorhabditis elegans glutamylating enzymes function redundantly in male mating.

    Science.gov (United States)

    Chawla, Daniel G; Shah, Ruchi V; Barth, Zachary K; Lee, Jessica D; Badecker, Katherine E; Naik, Anar; Brewster, Megan M; Salmon, Timothy P; Peel, Nina

    2016-09-15

    Microtubule glutamylation is an important modulator of microtubule function and has been implicated in the regulation of centriole stability, neuronal outgrowth and cilia motility. Glutamylation of the microtubules is catalyzed by a family of tubulin tyrosine ligase-like (TTLL) enzymes. Analysis of individual TTLL enzymes has led to an understanding of their specific functions, but how activities of the TTLL enzymes are coordinated to spatially and temporally regulate glutamylation remains relatively unexplored. We have undertaken an analysis of the glutamylating TTLL enzymes in C. elegans We find that although all five TTLL enzymes are expressed in the embryo and adult worm, loss of individual enzymes does not perturb microtubule function in embryonic cell divisions. Moreover, normal dye-filling, osmotic avoidance and male mating behavior indicate the presence of functional amphid cilia and male-specific neurons. A ttll-4(tm3310); ttll-11(tm4059); ttll-5(tm3360) triple mutant, however, shows reduced male mating efficiency due to a defect in the response step, suggesting that these three enzymes function redundantly, and that glutamylation is required for proper function of the male-specific neurons.

  5. Radiation effects on life span in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-09-01

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

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

    Science.gov (United States)

    Van Buskirk, Cheryl; Sternberg, Paul W

    2007-10-01

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

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

    Science.gov (United States)

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

    2012-10-02

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

  8. Gene expression markers for Caenorhabditis elegans vulval cells.

    Science.gov (United States)

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

    2002-12-01

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

  9. Synaptic polarity of the interneuron circuit controlling C. elegans locomotion

    Directory of Open Access Journals (Sweden)

    Franciszek eRakowski

    2013-10-01

    Full Text Available C. elegans is the only animal for which a detailed neural connectivity diagram has been constructed. However, synaptic polarities in this diagram, and thus, circuit functions are largely unknown. Here, we deciphered the likely polarities of 7 pre-motor neurons implicated in the control of worm's locomotion, using a combination of experimental and computational tools. We performed single and multiple laser ablations in the locomotor interneuron circuit and recorded times the worms spent in forward and backward locomotion. We constructed a theoretical model of the locomotor circuit and searched its all possible synaptic polarity combinations and sensory input patterns in order to find the best match to the timing data. The optimal solution is when either all or most of the interneurons are inhibitory and forward interneurons receive the strongest input, which suggests that inhibition governs the dynamics of the locomotor interneuron circuit. From the five pre-motor interneurons, only AVB and AVD are equally likely to be excitatory, i.e. they have probably similar number of inhibitory and excitatory connections to distant targets. The method used here has a general character and thus can be also applied to other neural systems consisting of small functional networks.

  10. Synaptic polarity of the interneuron circuit controlling C. elegans locomotion.

    Science.gov (United States)

    Rakowski, Franciszek; Srinivasan, Jagan; Sternberg, Paul W; Karbowski, Jan

    2013-01-01

    Caenorhabditis elegans is the only animal for which a detailed neural connectivity diagram has been constructed. However, synaptic polarities in this diagram, and thus, circuit functions are largely unknown. Here, we deciphered the likely polarities of seven pre-motor neurons implicated in the control of worm's locomotion, using a combination of experimental and computational tools. We performed single and multiple laser ablations in the locomotor interneuron circuit and recorded times the worms spent in forward and backward locomotion. We constructed a theoretical model of the locomotor circuit and searched its all possible synaptic polarity combinations and sensory input patterns in order to find the best match to the timing data. The optimal solution is when either all or most of the interneurons are inhibitory and forward interneurons receive the strongest input, which suggests that inhibition governs the dynamics of the locomotor interneuron circuit. From the five pre-motor interneurons, only AVB and AVD are equally likely to be excitatory, i.e., they have probably similar number of inhibitory and excitatory connections to distant targets. The method used here has a general character and thus can be also applied to other neural systems consisting of small functional networks.

  11. Uncoupling of Longevity and Telomere Length in C. elegans.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available The nematode Caenorhabditis elegans, after completing its developmental stages and a brief reproductive period, spends the remainder of its adult life as an organism consisting exclusively of post-mitotic cells. Here we show that telomere length varies considerably in clonal populations of wild-type worms, and that these length differences are conserved over at least ten generations, suggesting a length regulation mechanism in cis. This observation is strengthened by the finding that the bulk telomere length in different worm strains varies considerably. Despite the close correlation of telomere length and clonal cellular senescence in mammalian cells, nematodes with long telomeres were neither long lived, nor did worm populations with comparably short telomeres exhibit a shorter life span. Conversely, long-lived daf-2 and short-lived daf-16 mutant animals can have either long or short telomeres. Telomere length of post-mitotic cells did not change during the aging process, and the response of animals to stress was found independent of telomere length. Collectively, our data indicate that telomere length and life span can be uncoupled in a post-mitotic setting, suggesting separate pathways for replication-dependent and -independent aging.

  12. Regulation of DAF-16-mediated Innate Immunity in Caenorhabditis elegans.

    Science.gov (United States)

    Singh, Varsha; Aballay, Alejandro

    2009-12-18

    Activation of the innate immune system results in a rapid microbicidal response against microorganisms, which needs to be fine-tuned because uncontrolled immune responses can lead to infection and cancer, as well as conditions such as Crohn disease, atherosclerosis, and Alzheimer disease. Here we report that excessive activity of the conserved FOXO transcription factor DAF-16 enhances susceptibility to bacterial infections in Caenorhabditis elegans. We found that increased temperature activates not only DAF-16 nuclear import but also a control mechanism involved in DAF-16 nuclear export. The nuclear export of DAF-16 requires heat shock transcription factor HSF-1 and Hsp70/HSP-1. Furthermore, we show that increased expression of the water channel Aquoporin-1 is responsible for the deleterious consequences of excessive DAF-16-mediated immune response. These studies reveal a stress-inducible mechanism involved in the regulation of DAF-16 and indicate that uncontrolled DAF-16 activity and water homeostasis are a cause of the deleterious effects of excessive immune responses.

  13. A remote control for the C. elegans nervous system

    Science.gov (United States)

    Leifer, Andrew M.; Fang-Yen, Christopher; Samuel, Aravinthan D. T.

    2010-03-01

    We demonstrate a closed-loop optogenetic illumination system to stimulate or inhibit arbitrary patterns of neurons and muscle in a freely roaming worm. Transgenic worms that express light-sensitive ion channels in neurons or muscle are used. A microscope with a video camera records the worm's posture and motion. As the worm moves unrestrained, custom real-time image processing software analyzes the worm's position and estimates the location of targeted muscle and neuron cells. For each frame captured by the camera, the software generates an illumination pattern and directs a digital mirror device to shine laser light onto the targeted cells. The system can illuminate an arbitrary spatial and temporal pattern and thus can selectively inhibit or stimulate different sets of cells during the course of a single experiment. The image processing software is very fast and analyzes a 1024 by 768 pixel image containing a worm in less than 10ms. The system has been tested using worms expressing Channelrhodopsin and Halorhodopsin in both neurons and muscle. Preliminary results from an investigation of the C. elegans motor circuit are shown.

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

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    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.

  15. 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.

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

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    Zuryn, Steven; Kuang, Jujiao; Ebert, Paul

    2008-03-01

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

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

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    Sara Andux

    2008-12-01

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

  18. Adaptive capacity to bacterial diet modulates aging in C. elegans.

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    Pang, Shanshan; Curran, Sean P

    2014-02-04

    Diet has a substantial impact on cellular metabolism and physiology. Animals must sense different food sources and utilize distinct strategies to adapt to diverse diets. Here we show that Caenorhabditis elegans lifespan is regulated by their adaptive capacity to different diets, which is controlled by alh-6, a conserved proline metabolism gene. alh-6 mutants age prematurely when fed an Escherichia coli OP50 but not HT115 diet. Remarkably, this diet-dependent aging phenotype is determined by exposure to food during development. Mechanistically, the alh-6 mutation triggers diet-induced mitochondrial defects and increased generation of ROS, likely due to accumulation of its substrate 1-pyrroline-5-carboxylate. We also identify that neuromedin U receptor signaling is essential for diet-induced mitochondrial changes and premature aging. Moreover, dietary restriction requires alh-6 to induce longevity. Collectively, our data reveal a homeostatic mechanism that animals employ to cope with potential dietary insults and uncover an example of lifespan regulation by dietary adaptation.

  19. Phosphoregulation of the C. elegans cadherin-catenin complex.

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    Callaci, Sandhya; Morrison, Kylee; Shao, Xiangqiang; Schuh, Amber L; Wang, Yueju; Yates, John R; Hardin, Jeff; Audhya, Anjon

    2015-12-15

    Adherens junctions play key roles in mediating cell-cell contacts during tissue development. In Caenorhabditis elegans embryos, the cadherin-catenin complex (CCC), composed of the classical cadherin HMR-1 and members of three catenin families, HMP-1, HMP-2 and JAC-1, is necessary for normal blastomere adhesion, gastrulation, ventral enclosure of the epidermis and embryo elongation. Disruption of CCC assembly or function results in embryonic lethality. Previous work suggests that components of the CCC are subject to phosphorylation. However, the identity of phosphorylated residues in CCC components and their contributions to CCC stability and function in a living organism remain speculative. Using mass spectrometry, we systematically identify phosphorylated residues in the essential CCC subunits HMR-1, HMP-1 and HMP-2 in vivo. We demonstrate that HMR-1/cadherin phosphorylation occurs on three sites within its β-catenin binding domain that each contributes to CCC assembly on lipid bilayers. In contrast, phosphorylation of HMP-2/β-catenin inhibits its association with HMR-1/cadherin in vitro, suggesting a role in CCC disassembly. Although HMP-1/α-catenin is also phosphorylated in vivo, phosphomimetic mutations do not affect its ability to associate with other CCC components or interact with actin in vitro. Collectively, our findings support a model in which distinct phosphorylation events contribute to rapid CCC assembly and disassembly, both of which are essential for morphogenetic rearrangements during development.

  20. Challenging muscle homeostasis uncovers novel chaperone interactions in Caenorhabditis elegans

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    Frumkin, Anna; Dror, Shiran; Pokrzywa, Wojciech; Bar-Lavan, Yael; Karady, Ido; Hoppe, Thorsten; Ben-Zvi, Anat

    2014-01-01

    Proteome stability is central to cellular function and the lifespan of an organism. This is apparent in muscle cells, where incorrect folding and assembly of the sarcomere contributes to disease and aging. Apart from the myosin-assembly factor UNC-45, the complete network of chaperones involved in assembly and maintenance of muscle tissue is currently unknown. To identify additional factors required for sarcomere quality control, we performed genetic screens based on suppressed or synthetic motility defects in Caenorhabditis elegans. In addition to ethyl methyl sulfonate-based mutagenesis, we employed RNAi-mediated knockdown of candidate chaperones in unc-45 temperature-sensitive mutants and screened for impaired movement at permissive conditions. This approach confirmed the cooperation between UNC-45 and Hsp90. Moreover, the screens identified three novel co-chaperones, CeHop (STI-1), CeAha1 (C01G10.8) and Cep23 (ZC395.10), required for muscle integrity. The specific identification of Hsp90 and Hsp90 co-chaperones highlights the physiological role of Hsp90 in myosin folding. Our work thus provides a clear example of how a combination of mild perturbations to the proteostasis network can uncover specific quality control modules. PMID:25988162

  1. 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.

  2. The forward undulatory locomotion of Ceanorhabditis elegans in viscoelastic fluids

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    Shen, Amy; Ulrich, Xialing

    2013-11-01

    Caenorhabditis elegans is a soil dwelling roundworm that has served as model organisms for studying a multitude of biological and engineering phenomena. We study the undulatory locomotion of nematode in viscoelastic fluids with zero-shear viscosity varying from 0.03-75 Pa .s and relaxation times ranging from 0-350 s. We observe that the averaged normalized wavelength of swimming worm is essentially the same as that in Newtonian fluids. The undulatory frequency f shows the same reduction rate with respect to zero-shear viscosity in viscoelastic fluids as that found in the Newtonian fluids, meaning that the undulatory frequency is mainly controlled by the fluid viscosity. However, the moving speed Vm of the worm shows more distinct dependence on the elasticity of the fluid and exhibits a 4% drop with each 10-fold increase of the Deborah number De, a dimensionless number characterizing the elasticity of a fluid. To estimate the swimming efficiency coefficient and the ratio K =CN /CL of resistive coefficients of the worm in various viscoelastic fluids, we show that whereas it would take the worm around 7 periods to move a body length in a Newtonian fluid, it would take 27 periods to move a body length in a highly viscoelastic fluid.

  3. Undulatory locomotion of finite filaments: lessons from C. elegans

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    Leshansky, Alexander; Kenneth, Oded; Berman, Rotem; Sznitman, Josue

    2013-11-01

    Undulatory swimming is a widespread propulsion strategy adopted by many small-scale organisms including various single-cell eukaryotes and nematodes. In this work, we report a comprehensive study of undulatory locomotion of a finite filament using an approximate resistive force theory (RFT) and particle-based numerical computations. Using the ubiquitous model of a propagating sinusoidal waveform, we identify the limit of applicability of the RFT and determine the optimal propulsion gait in terms of (i) swimming distance covered per period of undulation and (ii) hydrodynamic propulsion efficiency. To compare the model sine swimmer to biological undulatory swimmers, we apply the particle-based approach to study locomotion of the of the model organism nematode Caenorhabditis elegans using the swimming gait extracted from experiments. The analysis reveals that the nematode overperforms the model sine swimmer in terms of both displacement and efficiency. Further comparison with common undulatory microorganisms reveals that many adopt waveforms with characteristics similar to the most efficient sine swimmer, yet real swimmers still manage to beat the latter in terms of speed. Our results emphasize the importance of the waveform optimization.

  4. Gene pathways that delay Caenorhabditis elegans reproductive senescence.

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    Meng C Wang

    2014-12-01

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

  5. Whole-Genome Profiling of Mutagenesis in Caenorhabditis elegans

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    Flibotte, Stephane; Edgley, Mark L.; Chaudhry, Iasha; Taylor, Jon; Neil, Sarah E.; Rogula, Aleksandra; Zapf, Rick; Hirst, Martin; Butterfield, Yaron; Jones, Steven J.; Marra, Marco A.; Barstead, Robert J.; Moerman, Donald G.

    2010-01-01

    Deep sequencing offers an unprecedented view of an organism's genome. We describe the spectrum of mutations induced by three commonly used mutagens: ethyl methanesulfonate (EMS), N-ethyl-N-nitrosourea (ENU), and ultraviolet trimethylpsoralen (UV/TMP) in the nematode Caenorhabditis elegans. Our analysis confirms the strong GC to AT transition bias of EMS. We found that ENU mainly produces A to T and T to A transversions, but also all possible transitions. We found no bias for any specific transition or transversion in the spectrum of UV/TMP-induced mutations. In 10 mutagenized strains we identified 2723 variants, of which 508 are expected to alter or disrupt gene function, including 21 nonsense mutations and 10 mutations predicted to affect mRNA splicing. This translates to an average of 50 informative mutations per strain. We also present evidence of genetic drift among laboratory wild-type strains derived from the Bristol N2 strain. We make several suggestions for best practice using massively parallel short read sequencing to ensure mutation detection. PMID:20439774

  6. The supramolecular organization of the C. elegans nuclear lamin filament.

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    Ben-Harush, Kfir; Wiesel, Naama; Frenkiel-Krispin, Daphna; Moeller, Dorothee; Soreq, Eyal; Aebi, Ueli; Herrmann, Harald; Gruenbaum, Yosef; Medalia, Ohad

    2009-03-13

    Nuclear lamins are involved in most nuclear activities and are essential for retaining the mechano-elastic properties of the nucleus. They are nuclear intermediate filament (IF) proteins forming a distinct meshwork-like layer adhering to the inner nuclear membrane, called the nuclear lamina. Here, we present for the first time, the three-dimensional supramolecular organization of lamin 10 nm filaments and paracrystalline fibres. We show that Caenorhabditis elegans nuclear lamin forms 10 nm IF-like filaments, which are distinct from their cytoplasmic counterparts. The IF-like lamin filaments are composed of three and four tetrameric protofilaments, each of which contains two partially staggered anti-parallel head-to-tail polymers. The beaded appearance of the lamin filaments stems from paired globular tail domains, which are spaced regularly, alternating between 21 nm and 27 nm. A mutation in an evolutionarily conserved residue that causes Hutchison-Gilford progeria syndrome in humans alters the supramolecular structure of the lamin filaments. On the basis of our structural analysis, we propose an assembly pathway that yields the observed 10 nm IF-like lamin filaments and paracrystalline fibres. These results serve also as a platform for understanding the effect of laminopathic mutations on lamin supramolecular organization.

  7. Morphogenesis during asexual reproduction in Pygospio elegans Claparede (Annelida, Polychaeta).

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    Gibson, G D; Harvey, J M

    2000-08-01

    The spionid Pygospio elegans reproduces both asexually and sexually. Using scanning electron and bright field microscopy, we examined morphogenesis following asexual reproduction to determine how "lost" body regions were regenerated after a worm spontaneously divided. Asexual reproduction occurred through transverse fission and divided the parent worm into 2 to 6 fragments (architomy). All fragments retained their original anterior-posterior polarity. Regeneration in all fragments followed a specific series of events: wound healing (day 1); extension of the blastema to generate lost body regions-specifically, the head and thorax for posterior fragments and the tail and pygidium for anterior fragments (days 2-3); segmentation (days 3-6); and differentiation of segment- or region-specific structures (days 4-8). This pattern occurred regardless of where the original division took place. Subsequent growth occurred through addition of terminal setigers anterior to the pygidium followed by differentiation of tail setigers into abdominal setigers, leaving the tail region about 6 to 10 setigers in size. Division rates were compared in worms from three populations in Nova Scotia, Canada. Worms from two populations (Conrad's Beach, Starr's Point) divided more frequently (about 1.2 and 1.3 weeks between divisions, respectively) than worms from Bon Portage Island (3.5 weeks between divisions). Fragments containing the original head (original mouth intact, generally much larger fragment) had a higher survivorship than fragments containing the original tail.

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

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

    2014-12-15

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

  9. Sperm status regulates sexual attraction in Caenorhabditis elegans.

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

    2011-12-01

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

  10. 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

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

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    Shane L Rea

    2007-10-01

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

  12. Heterologous Expression in Remodeled C. elegans: A Platform for Monoaminergic Agonist Identification and Anthelmintic Screening.

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    Wenjing Law

    2015-04-01

    Full Text Available Monoamines, such as 5-HT and tyramine (TA, paralyze both free-living and parasitic nematodes when applied exogenously and serotonergic agonists have been used to clear Haemonchus contortus infections in vivo. Since nematode cell lines are not available and animal screening options are limited, we have developed a screening platform to identify monoamine receptor agonists. Key receptors were expressed heterologously in chimeric, genetically-engineered Caenorhabditis elegans, at sites likely to yield robust phenotypes upon agonist stimulation. This approach potentially preserves the unique pharmacologies of the receptors, while including nematode-specific accessory proteins and the nematode cuticle. Importantly, the sensitivity of monoamine-dependent paralysis could be increased dramatically by hypotonic incubation or the use of bus mutants with increased cuticular permeabilities. We have demonstrated that the monoamine-dependent inhibition of key interneurons, cholinergic motor neurons or body wall muscle inhibited locomotion and caused paralysis. Specifically, 5-HT paralyzed C. elegans 5-HT receptor null animals expressing either nematode, insect or human orthologues of a key Gαo-coupled 5-HT1-like receptor in the cholinergic motor neurons. Importantly, 8-OH-DPAT and PAPP, 5-HT receptor agonists, differentially paralyzed the transgenic animals, with 8-OH-DPAT paralyzing mutant animals expressing the human receptor at concentrations well below those affecting its C. elegans or insect orthologues. Similarly, 5-HT and TA paralyzed C. elegans 5-HT or TA receptor null animals, respectively, expressing either C. elegans or H. contortus 5-HT or TA-gated Cl- channels in either C. elegans cholinergic motor neurons or body wall muscles. Together, these data suggest that this heterologous, ectopic expression screening approach will be useful for the identification of agonists for key monoamine receptors from parasites and could have broad application for

  13. A modular library of small molecule signals regulates social behaviors in Caenorhabditis elegans.

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    Jagan Srinivasan

    2012-01-01

    Full Text Available The nematode C. elegans is an important model for the study of social behaviors. Recent investigations have shown that a family of small molecule signals, the ascarosides, controls population density sensing and mating behavior. However, despite extensive studies of C. elegans aggregation behaviors, no intraspecific signals promoting attraction or aggregation of wild-type hermaphrodites have been identified. Using comparative metabolomics, we show that the known ascarosides are accompanied by a series of derivatives featuring a tryptophan-derived indole moiety. Behavioral assays demonstrate that these indole ascarosides serve as potent intraspecific attraction and aggregation signals for hermaphrodites, in contrast to ascarosides lacking the indole group, which are repulsive. Hermaphrodite attraction to indole ascarosides depends on the ASK amphid sensory neurons. Downstream of the ASK sensory neuron, the interneuron AIA is required for mediating attraction to indole ascarosides instead of the RMG interneurons, which previous studies have shown to integrate attraction and aggregation signals from ASK and other sensory neurons. The role of the RMG interneuron in mediating aggregation and attraction is thought to depend on the neuropeptide Y-like receptor NPR-1, because solitary and social C. elegans strains are distinguished by different npr-1 variants. We show that indole ascarosides promote attraction and aggregation in both solitary and social C. elegans strains. The identification of indole ascarosides as aggregation signals reveals unexpected complexity of social signaling in C. elegans, which appears to be based on a modular library of ascarosides integrating building blocks derived from lipid β-oxidation and amino-acid metabolism. Variation of modules results in strongly altered signaling content, as addition of a tryptophan-derived indole unit to repellent ascarosides produces strongly attractive indole ascarosides. Our findings show

  14. Caenorhabditis elegans: A Model System for Anti-Cancer Drug Discovery and Therapeutic Target Identification

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    Kobet, Robert A.; Pan, Xiaoping; Zhang, Baohong; Pak, Stephen C.; Asch, Adam S.; Lee, Myon-Hee

    2014-01-01

    The nematode Caenorhabditis elegans (C. elegans) offers a unique opportunity for biological and basic medical researches due to its genetic tractability and well-defined developmental lineage. It also provides an exceptional model for genetic, molecular, and cellular analysis of human disease-related genes. Recently, C. elegans has been used as an ideal model for the identification and functional analysis of drugs (or small-molecules) in vivo. In this review, we describe conserved oncogenic signaling pathways (Wnt, Notch, and Ras) and their potential roles in the development of cancer stem cells. During C. elegans germline development, these signaling pathways regulate multiple cellular processes such as germline stem cell niche specification, germline stem cell maintenance, and germ cell fate specification. Therefore, the aberrant regulations of these signaling pathways can cause either loss of germline stem cells or overproliferation of a specific cell type, resulting in sterility. This sterility phenotype allows us to identify drugs that can modulate the oncogenic signaling pathways directly or indirectly through a high-throughput screening. Current in vivo or in vitro screening methods are largely focused on the specific core signaling components. However, this phenotype-based screening will identify drugs that possibly target upstream or downstream of core signaling pathways as well as exclude toxic effects. Although phenotype-based drug screening is ideal, the identification of drug targets is a major challenge. We here introduce a new technique, called Drug Affinity Responsive Target Stability (DARTS). This innovative method is able to identify the target of the identified drug. Importantly, signaling pathways and their regulators in C. elegans are highly conserved in most vertebrates, including humans. Therefore, C. elegans will provide a great opportunity to identify therapeutic drugs and their targets, as well as to understand mechanisms underlying the

  15. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

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    Glendinning, Susan K; Buckingham, Steven D; Sattelle, David B; Wonnacott, Susan; Wolstenholme, Adrian J

    2011-01-01

    Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl) gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316) under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in some assays. C

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Braeckman, Bart P; Smolders, Arne; Back, Patricia; De Henau, Sasha

    2016-10-01

    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. 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. 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. 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.

  18. A modular library of small molecule signals regulates social behaviors in Caenorhabditis elegans.

    Science.gov (United States)

    Srinivasan, Jagan; von Reuss, Stephan H; Bose, Neelanjan; Zaslaver, Alon; Mahanti, Parag; Ho, Margaret C; O'Doherty, Oran G; Edison, Arthur S; Sternberg, Paul W; Schroeder, Frank C

    2012-01-01

    The nematode C. elegans is an important model for the study of social behaviors. Recent investigations have shown that a family of small molecule signals, the ascarosides, controls population density sensing and mating behavior. However, despite extensive studies of C. elegans aggregation behaviors, no intraspecific signals promoting attraction or aggregation of wild-type hermaphrodites have been identified. Using comparative metabolomics, we show that the known ascarosides are accompanied by a series of derivatives featuring a tryptophan-derived indole moiety. Behavioral assays demonstrate that these indole ascarosides serve as potent intraspecific attraction and aggregation signals for hermaphrodites, in contrast to ascarosides lacking the indole group, which are repulsive. Hermaphrodite attraction to indole ascarosides depends on the ASK amphid sensory neurons. Downstream of the ASK sensory neuron, the interneuron AIA is required for mediating attraction to indole ascarosides instead of the RMG interneurons, which previous studies have shown to integrate attraction and aggregation signals from ASK and other sensory neurons. The role of the RMG interneuron in mediating aggregation and attraction is thought to depend on the neuropeptide Y-like receptor NPR-1, because solitary and social C. elegans strains are distinguished by different npr-1 variants. We show that indole ascarosides promote attraction and aggregation in both solitary and social C. elegans strains. The identification of indole ascarosides as aggregation signals reveals unexpected complexity of social signaling in C. elegans, which appears to be based on a modular library of ascarosides integrating building blocks derived from lipid β-oxidation and amino-acid metabolism. Variation of modules results in strongly altered signaling content, as addition of a tryptophan-derived indole unit to repellent ascarosides produces strongly attractive indole ascarosides. Our findings show that the library of

  19. Glutamate-gated chloride channels of Haemonchus contortus restore drug sensitivity to ivermectin resistant Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Susan K Glendinning

    Full Text Available Anthelmintic resistance is a major problem in livestock farming, especially of small ruminants, but our understanding of it has been limited by the difficulty in carrying out functional genetic studies on parasitic nematodes. An important nematode infecting sheep and goats is Haemonchus contortus; in many parts of the world this species is resistant to almost all the currently available drugs, including ivermectin. It is extremely polymorphic and to date it has proved impossible to relate any sequence polymorphisms to its ivermectin resistance status. Expression of candidate drug-resistance genes in Caenorhabditis elegans could provide a convenient means to study the effects of polymorphisms found in resistant parasites, but may be complicated by differences between the gene families of target and model organisms. We tested this using the glutamate-gated chloride channel (GluCl gene family, which forms the ivermectin drug target and are candidate resistance genes. We expressed GluCl subunits from C. elegans and H. contortus in a highly resistant triple mutant C. elegans strain (DA1316 under the control of the avr-14 promoter; expression of GFP behind this promoter recapitulated the pattern previously reported for avr-14. Expression of ivermectin-sensitive subunits from both species restored drug sensitivity to transgenic worms, though some quantitative differences were noted between lines. Expression of an ivermectin-insensitive subunit, Hco-GLC-2, had no effect on drug sensitivity. Expression of a previously uncharacterised parasite-specific subunit, Hco-GLC-6, caused the transgenic worms to become ivermectin sensitive, suggesting that this subunit also encodes a GluCl that responds to the drug. These results demonstrate that both orthologous and paralogous subunits from C. elegans and H. contortus are able to rescue the ivermectin sensitivity of mutant C. elegans, though some quantitative differences were observed between transgenic lines in

  20. Understanding the role of asymmetric cell division in cancer using C. elegans.

    Science.gov (United States)

    Hyenne, Vincent; Chartier, Nicolas T; Labbé, Jean-Claude

    2010-05-01

    Asymmetric cell division is an important process to generate cell diversity and maintain tissue homeostasis. Recent evidence suggests that this process may also be crucial to prevent tumor formation. In the past 30 years, the embryo of the nematode Caenorhabditis elegans has proven to be a very powerful model to study the molecular and cellular basis of asymmetric cell division. Understanding this process in Caenorhabditis elegans may thus lead to a better understanding of stem cell function and tumorigenesis in humans. Copyright (c) 2010 Wiley-Liss, Inc.