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Sample records for pseudemys scripta elegans

  1. Magnetic resonance imaging measurements of organs within the coelomic cavity of red-eared sliders (Trachemys scripta elegans), yellow-bellied sliders (Trachemys scripta scripta), Coastal plain cooters (Pseudemys concinna floridana), and hieroglyphic river cooters (Pseudemys concinna hieroglyphica).

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    Mathes, Karina A; Schnack, Marcus; Rohn, Karl; Fehr, Michael

    2017-12-01

    OBJECTIVE To determine anatomic reference points for 4 turtle species and to evaluate data on relative anatomic dimensions, signal intensities (SIs), and position of selected organs within the coelomic cavity by use of MRI. ANIMALS 3 turtle cadavers (1 red-eared slider [Trachemys scripta elegans], 1 yellow-bellied slider [Trachemys scripta scripta], and 1 Coastal plain cooter [Pseudemys concinna floridana]) and 63 live adult turtles (30 red-eared sliders, 20 yellow-bellied sliders, 5 Coastal plain cooters, and 8 hieroglyphic river cooters [Pseudemys concinna hieroglyphica]). PROCEDURES MRI and necropsy were performed on the 3 turtle cadavers. Physical examination, hematologic evaluation, and whole-body radiography were performed on the 63 live turtles. Turtles were sedated, and MRI in transverse, sagittal, and dorsal planes was used to measure organ dimensions, position within the coelomic cavity, and SIs. Body positioning after sedation was standardized with the head, neck, limbs, and tail positioned in maximum extension. RESULTS Measurements of the heart, liver, gallbladder, and kidneys in sagittal, transverse, and dorsal planes; relative position of those organs within the coelom; and SIs of the kidneys and liver were obtained with MRI and provided anatomic data for these 4 turtle species. CONCLUSIONS AND CLINICAL RELEVANCE MRI was a valuable tool for determining the position, dimensions, and SIs of selected organs. Measurement of organs in freshwater chelonians was achievable with MRI. Further studies are needed to establish reference values for anatomic structures in turtles. Results reported here may serve as guidelines and aid in clinical interpretation of MRI images for these 4 species.

  2. Trachemys scripta elegans

    Indian Academy of Sciences (India)

    Ten polymorphic microsatellites were isolated from the red-eared slider, Trachemys scripta elegans, with a partial genomic library enriched for tandem repeat sequences of. (CA)12 and (GA)12. For these markers polymorphism was investigated in 30 individuals collected from Yuehe pet mar- ket in Guangzhou, China.

  3. Circulatory mechanoreceptors in the pond turtle Pseudemys scripta.

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    Faraci, F M; Shirer, H W; Orr, J A; Trank, J W

    1982-03-01

    This study was undertaken to characterize cardiovascular receptors in the turtle, Pseudemys scripta, with particular attention being given to neural activity changes associated with alterations in blood pressure. Vagal afferent nerve traffic, synchronous with heart contractions, was recorded in anesthetized artificially ventilated turtles. Action potentials, from receptors that fired regularly during each heart cycle, occurred during ventricular systole. Mechanical probing and vascular occlusion indicated that these receptors were located in the proximal common pulmonary artery including the bulbus cordis region. Bolus injections of saline into the ventricle or the common pulmonary artery caused immediate but transient increases in cardiac synchronous traffic. Prolonged elevation of arterial and ventricular blood pressure, by either saline injection or arterial occlusion, caused increases in receptor discharge of the same duration as the pressure increases. Although these receptors could participate in the regulation of the systemic and the pulmonary circulation, the physiological role for them is presently unknown.

  4. Ultraestructura de la cáscara del huevo de la tortuga Pseudemys scripta (Testudines: Emnydidae).

    OpenAIRE

    Acuña-Mesén, Rafael Arturo

    2016-01-01

    La cáscara del huevo de Pseudemys scripta consta de una capa externa de sales de calcio y una membrana proteica. La primera está formada por unidades estructurales que tienen muy variadas formas y tamaños según su número de subunidades. Entre cada unidad estructural se localizan grietas que sustituyen en su función a los poros observados en huevos de otras especies y que facilitan la expansión del huevo cuando está turgente; superficial y radialmente, éstas están compuestas por series de lame...

  5. La reproducción de la "Icotea": (Pseudemys scripta callirostris, (Testudines Emydidae La reproducción de la "Icotea": (Pseudemys scripta callirostris, (Testudines Emydidae

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    Medem Federico

    1975-09-01

    Full Text Available 1. The first exact data about reproduction of the Colombian Painted Turtle, Pseudemys scripta callirostris, are presented, based on studies carried out on 75 adults, 89 hatchlings and 276 eggs.2. There exists a marked sexual dimorphism which comprises the size of the shell, length of tail, and shape of shell and head. The Carapace length, taken in straight line, is up to 300.0 mm in ♀♀ and 252.0 mm in ♂ ♂, but generally less.3. The mating season takes place between September and December.4. Copulation takes place in quiet but deep water and lasts for about 2-3 minutes.5. Only the hind legs are used to excavate the nest; the entire process (excavation, egg laying and covering of the hole lasts between one hour, twenty minutes and four hours, twenty five minutes aproximately. (Figs. 1-2.6. The flask-shaped nesting hole is up to 180.0 mm deep, 110.0 mm wide at the entrance and 130.0 mm wide at the bottom. (Table 1.7. There are from 9-30 eggs to be found in a single nest which are deposited in 2-3-4 layers; the first eggs (last layer are found in 67.0 mm-10.0mm depth. (Table 3.8. The oblong, soft-shelled eggs are pinkish-white when recently laid, they show, moreover, a shallow concavity about 19.0 mm-21.0 mm long. In contrast, those already containing embryos have a less flexible shell, no concavity and are white. (Fig. 3-4.9. The measurements and weight of 152 eggs comprises from 41.0:26.0 mm to 27.0:21.0 mm, and between 15 g, 670 mg and 5 g, 170 mg respectively. (Table 4.10. The egg-laying season takes place principally between late December and late April; according to information there is a second one in August but to a lesser degree; dissected ♀♀ contained both eggs and numerous ovules. (Table 2.11. The incubation period varies between 69 and 92 days. (Table 6.12. Hatchlings are born from late april to early June. 13. The Carapace length ranges from 39.0 mm to 29.5 mm, and the weight varies between 13 g, 300 mg and 7 g, 60 mg

  6. Long-term retention of visual tasks by two species of emydid turtles, Pseudemys nelsoni and Trachemys scripta.

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    Davis, Karen M; Burghardt, Gordon M

    2012-08-01

    Long-lived species are expected to have long-term memory capabilities. In this study we tested nine Florida Red-bellied Cooters (Pseudemys nelsoni) on their retention for both a procedural food acquisition task and visual discrimination task learned in a previous experiment. The turtles were tested and retrained after two months, after another 7.5 months, and finally after 36 months of no interaction with the test apparatus during the intervening periods. Turtles retained memory for the choice task and needed little retraining throughout. Furthermore, in a different visual discrimination task, both P. nelsoni and Trachemys scripta turtles showed 100% retention after 3.5 months of no testing. Odor-controlled tests confirmed that turtles were using visual cues to solve the task. Thus, in a laboratory context turtles demonstrate long-term memory of visual discrimination tasks, which relates to apparent abilities in natural environments. 2012 APA, all rights reserved

  7. Nitric oxide synthase in the brain of the turtle Pseudemys scripta elegans.

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    Brüning, G; Wiese, S; Mayer, B

    1994-10-08

    The distribution pattern of nitric oxide synthase (NOS) was investigated in the brain of the turtle by NADPH-diaphorase histochemistry. The specificity of the histochemical staining was tested by immunocytochemical colocalization with an antiserum specific for NOS. In the forebrain, neurons staining intensely for nitric oxide synthase were localized in the olfactory tubercle, the basal ganglia complex, the basal amygdaloid nucleus, suprapeduncular nucleus, and the posterior hypothalamic area. Many positive fibers course in a tract connecting the basal amygdaloid nucleus with the hypothalamus, corresponding to the stria terminalis. Bundles of nitroxergic fibers were seen to course at the ventromedial edge of the optic tract and to cross in the supraoptic decussation, apparently consisting of tectothalamic and thalamotectal fibers. In the midbrain, strongly NOS-positive neurons were present in the substantia nigra, the nucleus profundus mesencephali, the periventricular grey of the optic tectum, the laminar nucleus of the torus semicircularis, and the nucleus of the lateral lemniscus. The area of the locus coeruleus harbored an accumulation of intensely stained neurons, which, as in mammals, might represent a cholinergic cell group of the reptilian brainstem. In the cerebellum, strong staining was confined to bundles of afferent fibers running in the lower molecular and in the Purkinje cell layer. These axons appeared to include ascending projections from the dorsal funicular nucleus or the spinal cord. NOS-positive cells in the caudal brainstem were found in the cerebellar nuclei, in the superior vestibular nucleus, in the reticular nuclei, ventrolateral to the nucleus of the solitary tract, in the perihypoglossal, and in the dorsal funicular nucleus. Taken together, these results suggest that nitric oxide acts as a messenger molecule in different areas of the reptilian brain and spinal cord. In certain areas, the pattern of expression of NOS appears to have evolved before radiation of present mammalian, avian, and reptilian species.

  8. BIOINFORMATICS MODEL OF THE CARAPACE SCUTE PATTERN OF THE RED-EARED SLIDER TRACHEMYS SCRIPTA ELEGANS (WIED-NEUWIED, 1839

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    Andrey Kiladze

    2017-10-01

    Full Text Available The scutes located on the carapace of the red-eared slider Trachemys scripta elegans (Wied-Neuwied, 1839 have been modeled. Bioinformatics modeling of carapace’s scutes were carried out by utilizing the Voronoi decomposition and Delaunay triangulation method. These two geometric techniques allow the patterns of vertebral and costal scutes to be recreated. The proposed model may have a certain value for taxonomy as well as for estimating the symmetry of the morphological structures, which is important for the purposes of biomimetics.

  9. Decline of red-eared sliders (Trachemys scripta elegans) and Texas spiny softshells (Apalone spinifera emoryi) in the Lower Rio Grande Valley of Texas

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    Donald J. Brown; Amanda D. Schultz; James R. Dixon; Brian E. Dickerson; Michael R. J. Forstner

    2012-01-01

    In 2009, we repeated a freshwater turtle survey first conducted in 1976 in the Lower Rio Grande Valley (LRGV) of Texas to determine whether the abundance of freshwater turtles in the LRGV has changed over the past three decades. We captured significantly fewer red-eared sliders (Trachemys scripta elegans) and Texas spiny softshells (Apalone spinifera emoryi) in 2...

  10. Morphological and mechanical changes in juvenile red-eared slider turtle (Trachemys scripta elegans) shells during ontogeny.

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    Fish, Jennifer F; Stayton, Charles T

    2014-04-01

    Turtles experience numerous modifications in the morphological, physiological, and mechanical characteristics of their shells through ontogeny. Although a general picture is available of the nature of these modifications, few quantitative studies have been conducted on changes in turtle shell shape through ontogeny, and none on changes in strength or rigidity. This study investigates the morphological and mechanical changes that juvenile Trachemys scripta elegans undergo as they increase in size. Morphology and shell rigidity were quantified in a sample of 36 alcohol-preserved juvenile Trachemys scripta elegans. Morphometric information was used to create finite element models of all specimens. These models were used to assess the mechanical behavior of the shells under various loading conditions. Overall, we find that turtles experience complementary changes in size, shape, deformability, and relative strength as they grow. As turtles age their shells become larger, more elongate, relatively flatter, and more rigid. These changes are associated with decreases in relative (size independent) strength, even though the shells of larger turtles are stronger in an absolute sense. Decreased deformability is primarily due to changes in the size of the animals. Residual variation in deformability cannot be explained by changes in shell shape. This variation is more likely due to changes in the degree of connectedness of the skeletal elements in the turtle's shells, along with changes in the thickness and degree of mineralization of shell bone. We suggest that the mechanical implications of shell size, shape, and deformability may have a large impact on survivorship and development in members of this species as they mature. Copyright © 2013 Wiley Periodicals, Inc.

  11. Characterization of Fructose-1,6-Bisphosphate Aldolase during Anoxia in the Tolerant Turtle, Trachemys scripta elegans: An Assessment of Enzyme Activity, Expression and Structure

    OpenAIRE

    Neal J. Dawson; Biggar, Kyle K.; Storey, Kenneth B.

    2013-01-01

    One of the most adaptive facultative anaerobes among vertebrates is the freshwater turtle, Trachemys scripta elegans. Upon a decrease in oxygen supply and oxidative phosphorylation, these turtles are able to reduce their metabolic rate and recruit anaerobic glycolysis to meet newly established ATP demands. Within the glycolytic pathway, aldolase enzymes cleave fructose-1,6-bisphosphate to triose phosphates facilitating an increase in anaerobic production of ATP. Importantly, this enzyme exist...

  12. Comparison of Gastrografin to barium sulfate as a gastrointestinal contrast agent in red-eared slider turtles (Trachemys scripta elegans).

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    Long, Charles Tyler; Page, Richard B; Howard, Antwain M; McKeon, Gabriel P; Felt, Stephen A

    2010-01-01

    Red-eared slider turtles (Trachemys scripta elegans) commonly develop intestinal obstruction. The gastrointestinal transit time in turtles tends to be longer than in other animals, making a rapid diagnosis of obstruction difficult. Fifteen red-eared sliders were given either Gastrografin or 30% w/v barium sulfate orally to compare ease of administration, transit time, and image quality. Each contrast medium was easy to administer but barium sulfate had to be administered more slowly (mean = 40s) than Gastrografin (mean = 20s) to prevent regurgitation. The mean transit and emptying time of Gastrografin was at least 9 h faster than barium sulfate at all time points except gastric transit. Both contrast media had a smooth, uniform appearance that outlined the mucosa with well-defined margins within the stomach and proximal small intestine. Dilution of Gastrografin occurred as it progressed through the intestines, resulting in decreased opacity in the distal small intestine and colon. Pre-administration packed cell volume and total serum protein levels of four turtles receiving Gastrografin were compared with levels at 24-, 96-, and 168-hours postadministration as well as to four control turtles not receiving contrast medium. Packed cell volume and total serum protein levels did not significantly differ among the Gastrografin and control group. From a clinical perspective, administration of Gastrografin allows for quicker results with only minor hematologic changes in red-eared sliders, but visualization of this contrast medium in the lower gastrointestinal tract may be insufficient for an accurate diagnosis.

  13. Identification of a functionally distinct truncated BDNF mRNA splice variant and protein in Trachemys scripta elegans.

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    Ganesh Ambigapathy

    Full Text Available Brain-derived neurotrophic factor (BDNF has a diverse functional role and complex pattern of gene expression. Alternative splicing of mRNA transcripts leads to further diversity of mRNAs and protein isoforms. Here, we describe the regulation of BDNF mRNA transcripts in an in vitro model of eyeblink classical conditioning and a unique transcript that forms a functionally distinct truncated BDNF protein isoform. Nine different mRNA transcripts from the BDNF gene of the pond turtle Trachemys scripta elegans (tBDNF are selectively regulated during classical conditioning: exon I mRNA transcripts show no change, exon II transcripts are downregulated, while exon III transcripts are upregulated. One unique transcript that codes from exon II, tBDNF2a, contains a 40 base pair deletion in the protein coding exon that generates a truncated tBDNF protein. The truncated transcript and protein are expressed in the naïve untrained state and are fully repressed during conditioning when full-length mature tBDNF is expressed, thereby having an alternate pattern of expression in conditioning. Truncated BDNF is not restricted to turtles as a truncated mRNA splice variant has been described for the human BDNF gene. Further studies are required to determine the ubiquity of truncated BDNF alternative splice variants across species and the mechanisms of regulation and function of this newly recognized BDNF protein.

  14. Metal accumulation in eggs of the red-eared slider (Trachemys scripta elegans) in the Lower Illinois River.

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    Tryfonas, Anna E; Tucker, John K; Brunkow, Paul E; Johnson, Kevin A; Hussein, Hussein S; Lin, Zhi-Qing

    2006-03-01

    The Illinois River is a highly utilized navigable waterway in the US Midwest, and has historically been contaminated with metal toxicants from various industrial and municipal pollution sources. Little information on metal contamination is available in the Lower Illinois River, and in particular, in the habitat of the red-eared slider (Trachemys scripta elegans) at the southern end of the river near Grafton, IL. This study was conducted to determine current levels of metal contamination in water, sediment, soil, and plants in the habitat, as well as to reveal temporal and spatial variations of metal accumulation in eggs of the red-eared slider. Aluminum, Cd, Cr, Cu, Mn, Ni, Pb, V, Sn, and Zn were analyzed by inductively-coupled plasma spectroscopy. High concentrations of metals were observed in lake sediment, compared with the concentrations in water, soil, and plant tissues. Sediment Ni concentrations (mg kg(-1)) varied from 66 to 95 and Sn from 1100 to 1600. Five detectable metals in egg content were Zn (24.2 +/- 13), Al (2.2 +/- 1.2), Sn (1.8 +/- 1.1), Mn (1.1 +/- 0.6), and Cu (0.9 +/- 0.5); nine detectable metals in egg shell were Zn (6.8 +/- 3.9), Sn (3.7 +/- 3.1), Cu (1.9 +/- 1.3), Cr (1.6 +/- 1.5), V (1.6 +/- 1.4), Pb (1.3 +/- 0.7), Ni (1.3 +/- 0.9), Mn (1.0 +/- 0.8), and Cd (0.16 +/- 0.11). Zinc accumulation in egg content was significantly correlated with Zn in egg shell (r = 0.445, P < 0.002, n = 42). While significant spatial variation was observed in egg shell, metal accumulation in eggs (content and shell) collected from the same ground of turtles consecutively for 4 years did not show a significant temporal change.

  15. Topografia, morfologia e irrigação do Baço em Trachemys scripta elegans (WIED, 1838

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    Marcelo Domingues de Faria

    2007-06-01

    Full Text Available Utilizou-se vinte tartarugas da espécie Trachemys scripta elegans, sendo duas fêmeas jovens, quatro fêmeas adultas, oito machos jovens e seis machos adultos. Inicialmente, retirou-se o plastrão, isolando-se o coração e, já na aorta descendente, introduziu-se uma cânula antes da bifurcação da aorta para injeção de solução de látex corado com pigmento vermelho para identificarmos as artérias com maior precisão. Após a injeção, os animais foram colocados em solução aquosa de formaldeído 20% por período não inferior a 72 horas e, posteriormente, dissecamos as artérias responsáveis pela irrigação do baço. Observou-se em 30% dos casos, o baço posicionado caudalmente ao cólon transverso e, em 70%, cranialmente ao mesmo, mas sempre apoiado neste segmento intestinal. Com relação à irrigação do baço, observou-se que em 95% dos casos, o maior aporte sangüíneo era proveniente da artéria mesentérica cranial, onde apenas 30% dos animais apresentavam irrigação somente pela artéria lienal; já em 40% apresentavam irrigação pela artéria lienal e pequenos ramos da artéria cólica esquerda. Em 5% dos casos era irrigado pela artéria lienal e por um único ramo emitido por uma das artérias jejunais, 5% eram irrigados pela artéria lienal e por um ramo da artéria pancreaticaduodenal cranial e por uma artéria que tinha origem no tronco comum das artérias jejunais; 15% dos animais tinham seu baço irrigado pela artéria lienal e por ramos da artéria pancreaticaduodenal cranial. Em 5% dos animais observamos o baço sendo irrigado apenas por ramificações da artéria cólica esquerda.

  16. Effects of topical insulin on second-intention wound healing in the red-eared slider turtle (Trachemys scripta elegans) - a controlled study.

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    Negrini, Joao; Mozos, Elena; Escamilla, Alejandro; Pérez, José; Lucena, Rosario; Guerra, Rafael; Ginel, Pedro J

    2017-06-06

    Compared with mammals, wound healing in reptiles is characterized by reduced wound contraction and longer healing times. The aim of this study is to describe the clinical and histopathological effects of topical insulin on second-intention healing of experimentally induced wounds in skin without dermal bony plates of Trachemys scripta elegans exposed to daily variations in ambient temperature and in an aquatic environment. Forty-four healthy adult females were assigned to two groups: Group 1 (n = 24) was used to assess clinical features such as wound contraction; Group 2 (n = 20) was used for histological evaluation and morphometric analysis. Topical porcine insulin (5 IU/ml diluted in glycerol) was applied daily 1 week. For each control time (2, 7, 14, 21 and 28 days post-wounding), re-epithelisation and wound remodelling were evaluated histologically and the number of main inflammatory cells (heterophils, macrophages, lymphocytes and fibroblasts) was scored. Mean wound contraction was higher in the insulin-treated group at each time point and differences were significant at day 28 (P insulin-treated wounds had significantly higher mean counts of heterophils (day 7), macrophages (days 2, 7 and 14) and fibroblasts (days 14 and 21), whereas lymphocyte counts were significantly lower at day 21. These results demonstrate that topical insulin modifies the inflammatory response of turtle skin up-regulating inflammatory cells at early stages and promoting wound healing. Topical insulin is a potentially useful therapy in skin wounds of Trachemys scripta and should be evaluated in non-experimental wounds of turtles and other reptiles.

  17. Honest sexual signaling in turtles: experimental evidence of a trade-off between immune response and coloration in red-eared sliders Trachemys scripta elegans.

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    Ibáñez, Alejandro; Polo-Cavia, Nuria; López, Pilar; Martín, José

    2014-10-01

    Sexual signals can be evolutionarily stable if they are honest and condition dependent or costly to the signaler. One possible cost is the existence of a trade-off between maintaining the immune system and the elaboration of ornaments. This hypothesis has been experimentally tested in some groups of animals but not in others such as turtles. We experimentally challenged the immune system of female red-eared sliders Trachemys scripta elegans, with a bacterial antigen (lipopolysaccharide (LPS)) without pathogenic effects to explore whether the immune activation affected visual colorful ornaments of the head. The LPS injection altered the reflectance patterns of color ornaments. In comparison to the control animals, the yellow chin stripes of injected animals exhibited (1) reduced brightness, (2) lower long wavelength (>470 nm) reflectance, and (3) lower values for carotenoid chroma. The postorbital patches of injected individuals also showed reduced very long wavelength (>570 nm) reflectance but did not change in carotenoid chroma. Thus, experimental turtles showed darker and less "yellowish" chin stripes and less "reddish" postorbital patches at the end of the experiment, whereas control turtles did not change their coloration. This is the first experimental evidence supporting the existence of a trade-off between the immune system and the expression of visual ornaments in turtles. We suggest that this trade-off may allow turtles to honestly signal individual quality via characteristics of coloration, which may have an important role in intersexual selection processes.

  18. Clinical and histological findings of cutaneous wound healing in the red-eared slider turtle (Trachemys scripta elegans) housed in unheated outdoor enclosures.

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    Negrini, Joao; Ginel, Pedro J; Novales, Manuel; Guerra, Rafael; Mozos, Elena

    2016-10-01

    Cutaneous wounds are common in chelonians. The clinical and histological features of wound healing in these species are not well described and this prevents evaluation of new therapies. To describe clinical and histopathological features of cutaneous wound healing in the red-eared slider turtle (Trachemys scripta elegans). Twenty four healthy adult females housed in outdoor facilities with free access to water and exposed to daily variations in temperature. Full thickness 6 mm skin biopsy punch wounds were created in the rear limbs. The turtles were assigned to Group 1 (n = 12 for clinical evaluation) and Group 2 (n = 12 for microscopic study). Group 1 was photographed on Day 1 and weekly, until 28 days post wounding. Wound retraction was expressed as the percentage of perimeter reduction. For Group 2, three skin wounds were sampled at 2, 7, 14, 21, 28, 42, 60 and 135 days post wounding for histological study. The avidin-biotin-peroxidase (ABC) staining method was used to evaluate five commercial antibodies. Wound contraction was limited; crust persisted at least 28 days. Re-epithelialization was complete by Day 14 in many animals; active inflammation persisted until 28 days; connective tissue re-constitution and remodelling was achieved from 42 to 135 days. Antibodies AE1/AE3, Factor VIII, MAC 387, CD3 and NCL-MSA showed cross reactivity with the cell counterpart in turtle tissues. Second intention wound healing progressed slowly and with an indolent behaviour. Microscopically there was marked overlapping of the inflammatory and proliferative phases over a long time period. © 2016 ESVD and ACVD.

  19. Characterization of fructose-1,6-bisphosphate aldolase during anoxia in the tolerant turtle, Trachemys scripta elegans: an assessment of enzyme activity, expression and structure.

    Science.gov (United States)

    Dawson, Neal J; Biggar, Kyle K; Storey, Kenneth B

    2013-01-01

    One of the most adaptive facultative anaerobes among vertebrates is the freshwater turtle, Trachemys scripta elegans. Upon a decrease in oxygen supply and oxidative phosphorylation, these turtles are able to reduce their metabolic rate and recruit anaerobic glycolysis to meet newly established ATP demands. Within the glycolytic pathway, aldolase enzymes cleave fructose-1,6-bisphosphate to triose phosphates facilitating an increase in anaerobic production of ATP. Importantly, this enzyme exists primarily as tissue-specific homotetramers of aldolase A, B or C located in skeletal muscle, liver and brain tissue, respectively. The present study characterizes aldolase activity and structure in the liver tissue of a turtle whose survival greatly depends on increased glycolytic output during anoxia. Immunoblot and mass spectrometry analysis verified the presence of both aldolase A and B in turtle liver tissue, and results from co-immunoprecipitation experiments suggested that in the turtle aldolase proteins may exist as an uncommon heterotetramer. Expression levels of aldolase A protein increased significantly in liver tissue to 1.59±0.11-fold after 20 h anoxia, when compared to normoxic control values (Pfructose-1,6-bisphosphate as substrate, were similar to that of a previously studied aldolase A and aldolase B heterotetramer, with a Km of 240 and 180 nM (for normoxic and anoxic turtle liver, respectively). Ligand docking of fructose-1,6-bisphosphate to the active site of aldolase A and B demonstrated minor differences in both protein:ligand interactions compared to rabbit models. It is likely that the turtle is unique in its ability to regulate a heterotetramer of aldolase A and B, with a higher overall enzymatic activity, to achieve greater rates of glycolytic output and support anoxia survival.

  20. Characterization of fructose-1,6-bisphosphate aldolase during anoxia in the tolerant turtle, Trachemys scripta elegans: an assessment of enzyme activity, expression and structure.

    Directory of Open Access Journals (Sweden)

    Neal J Dawson

    Full Text Available One of the most adaptive facultative anaerobes among vertebrates is the freshwater turtle, Trachemys scripta elegans. Upon a decrease in oxygen supply and oxidative phosphorylation, these turtles are able to reduce their metabolic rate and recruit anaerobic glycolysis to meet newly established ATP demands. Within the glycolytic pathway, aldolase enzymes cleave fructose-1,6-bisphosphate to triose phosphates facilitating an increase in anaerobic production of ATP. Importantly, this enzyme exists primarily as tissue-specific homotetramers of aldolase A, B or C located in skeletal muscle, liver and brain tissue, respectively. The present study characterizes aldolase activity and structure in the liver tissue of a turtle whose survival greatly depends on increased glycolytic output during anoxia. Immunoblot and mass spectrometry analysis verified the presence of both aldolase A and B in turtle liver tissue, and results from co-immunoprecipitation experiments suggested that in the turtle aldolase proteins may exist as an uncommon heterotetramer. Expression levels of aldolase A protein increased significantly in liver tissue to 1.59±0.11-fold after 20 h anoxia, when compared to normoxic control values (P<0.05. A similar increase was seen for aldolase B expression. The overall kinetic properties of aldolase, when using fructose-1,6-bisphosphate as substrate, were similar to that of a previously studied aldolase A and aldolase B heterotetramer, with a Km of 240 and 180 nM (for normoxic and anoxic turtle liver, respectively. Ligand docking of fructose-1,6-bisphosphate to the active site of aldolase A and B demonstrated minor differences in both protein:ligand interactions compared to rabbit models. It is likely that the turtle is unique in its ability to regulate a heterotetramer of aldolase A and B, with a higher overall enzymatic activity, to achieve greater rates of glycolytic output and support anoxia survival.

  1. Efeito do sítio de venopunção nos parâmetros hematológicos em tigre-d'água-americano, Trachemys scripta elegans Effect of the blood collection site on the hematological parameters in red-eared slider, Trachemys scripta elegans

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    Nina C. Medeiros

    2012-12-01

    Full Text Available O objetivo do presente estudo foi realizar a comparação entre dois sítios de coleta sanguínea em 24 exemplares de tigre-d'água-americano (Trachemys scripta elegans oriundos de um criadouro comercial, localizado no município de Antonina, litoral do Paraná, Brasil. Os animais foram submetidos a contenção física e as venopunções foram realizadas no seio supraocciptal e na veia coccígea dorsal. As amostras heparinizadas foram identificadas e refrigeradas para posterior análise laboratorial. A contagem total de eritrócitos e leucócitos foi realizada pela técnica de hemocitometria. O hematócrito (Ht e a hemoglobina (Hb foram determinados pelo método de microhematócrito e cianometahemoglobina, respectivamente. A proteína plasmática total (PPT foi determinada por refratometria e a contagem diferencial de leucócitos foi realizada através da técnica de Shilling. Houve diferença significativa no número de leucócitos e no valor da proteína plasmática total, e em ambos os casos os valores encontrados nas amostras provenientes da veia coccígea dorsal foram inferiores. A diferença encontrada no número de leucócitos provavelmente foi devido à contaminação por linfa, que também justifica o menor valor na concentração da proteína plasmática total. Conclui-se que é mais indicada a venopunção no seio supraocciptal quando comparado a veia coccígea dorsal.The aim of the present study was to compare two different blood collection sites of 24 red-eared sliders (Trachemys scripta elegans from a commercial breeder, situated in Antonina, Paraná, Brasil. The animals were physically restrained and paired blood samples were collected from the dorsal coccygeal vein and the occipital sinus. The samples were collected in syringes containing heparin. After collection the samples were identified and refrigerated to posterior hematological analysis. Red blood cell and white blood count were performed using a hemocytometer. The packed

  2. Unusual population attributes of invasive red-eared slider turtles (Trachemys scripta elegans) in Japan: do they have a performance advantage?

    Science.gov (United States)

    Taniguchi, Mari; Lovich, Jeffrey E.; Mine, Kanako; Ueno, Shintaro; Kamezaki, Naoki

    2017-01-01

    The slider turtle (Trachemys scripta Thunberg in Schoepff, 1792) is native to the USA and Mexico. Due to the popularity of their colorful hatchlings as pets, they have been exported worldwide and are now present on all continents, except Antarctica. Slider turtles are well-established in Japan and occupy aquatic habitats in urban and agricultural areas, to the detriment of native turtles with which they compete. We asked the overall question, do slider turtles in Japan have a performance advantage because they are liberated from the numerous competing turtle species in their native range and released from many of their natural predators? Traits compared included various measures of adult body size (mean, maximum), female size at maturity as measured by size of gravid females, clutch size, population density and biomass, sex ratio, and sexual size dimorphism, the latter two a partial reflection of growth and maturity differences between the sexes. We sampled slider turtle populations in three habitats in Japan and compared population attributes with published data for the species from throughout its native range in the USA. Mean male body sizes were at the lower end of values from the USA suggesting that males in Japan may mature at smaller body sizes. The smallest gravid females in Japan mature at smaller body sizes but have mean clutch sizes larger than some populations in the USA. Compared to most populations in the USA, slider turtles achieve higher densities and biomasses in Japanese wetlands, especially the lotic system we sampled. Sex ratios were female-biased, the opposite of what is reported for many populations in protected areas of the USA. Sexual size dimorphism was enhanced relative to native populations with females as the larger sex. The enhanced dimorphism is likely a result of earlier size of maturity in Japanese males and the large size of mature (gravid) Japanese females. Slider turtles appear to have a performance advantage over native turtles in

  3. Rahvusvaheline "Scripta manent II" Tallinnas

    Index Scriptorium Estoniae

    2000-01-01

    Eduard Taska 110. sünniaastapäevale pühendatud rahvusvaheline köitekunsti- ja kalligraafianäitus "Scripta manent II" Tallinna Kunstihoones. Köitekunsti osas pälvis "kuldraamatu" Marielle Liivat, ergutusauhinnad: Marje Kask, Kadi Kiipus, Urve Kolde

  4. Male sex steroids and hormonal control of male courtship behavior in the yellow-bellied slider turtle, Trachemys scripta

    Science.gov (United States)

    Garstka, W.R.; Cooper, W.E.; Wasmund, K.W.; Lovich, J.E.

    1991-01-01

    Survey of androgens and estrogens in serum, liver and testes of male yellow-bellied slider turtles, Trachemys (= Pseudemys) scripta, a species exhibiting dissociated gametogenesis age-dependent melanism, revealed the presence of numerous androgen precursors, androgens, androgen metabolites, and estrogens in quantities varying with season, tissue, and male coloration.The most commonly found and abundant androgens in all males were dehydroepiandrosterone (DHEA) and androstenedione, which were present at significantly higher levels in testes than in serum or liver.Epitestosterone was found in the serum and liver of only melanistic males; testosterone was only rarely recovered.Behavioral testing of castrated male turtles implanted with various androgens, as well as intact and sham-operated controls, revealed that melanistic males courted more frequently than nonmelanistic males, and that exogenous testosterone was most effective in inducing courtship behavior in castrated males.

  5. La revista Scripta Nova en 2006

    OpenAIRE

    Casals Costa, Vicente, 1951-; Capel Sáez, Horacio, 1941-; Bouza Vila, Jerónimo

    2006-01-01

    Se efectúa un balance de tipo bibliométrico de los artículos publicados en Scripta Nova durante el año 2006. Se incluyen diversas evaluaciones sobre el papel desempañado por Scripta Nova dentro del conjunto de publicaciones de contenido geográfico de Cataluña, así como del impacto intelectual de la revista en los últimos años.

  6. TEMPERATURE SELECTION BY HATCHLING AND YEARLING FLORIDA RED-BELLIED TURTLES (PSEUDEMYS NELSONI) IN THERMAL GRADIENTS

    Science.gov (United States)

    We tested hatchling and yearling Florida red-bellied turtles (Pseudemys nelsoni) in laboratory thermal gradient chambers to determine if they would prefer particular temperatures. Most 1995 hatchlings selected the highest temperature zone of 27degrees C (Test 1) and 30 degrees ...

  7. EDITORIAL: 40 years of Physica Scripta 40 years of Physica Scripta

    Science.gov (United States)

    Wäppling, Roger

    2010-01-01

    Physica Scripta is an international journal published by the Royal Swedish Academy of Sciences since 1970. It covers all aspects of physics and is one of the few general (broadband) physics journals still around that publishes 'full-length' research papers. The involvement of the Royal Swedish Academy of Sciences in scientific publication began in 1903 with Arkiv för matematik, astronomi och fysik. This journal collected results in the fields of mathematics, astronomy and physics. In 1949 it was divided into four independent journals: Arkiv för astronomi, Arkiv för fysik, Arkiv för geofysik and Arkiv för matematik. Subsequently, a total of 40 volumes of Arkiv för fysik were published until its replacement by Physica Scripta in 1970. When Physica Scripta was started, the emphasis was on articles contributed from the Scandinavian countries, including Finland. These restrictions on submissions became further evident when other Nordic science academies and physical societies were invited to participate in the publication process. Nowadays, the main journal, published in 12 monthly issues, carries the subtitle 'An international journal for experimental and theoretical physics' and is a truly international journal both in terms of circulation and of submitted and published articles. The contributions from the Nordic countries are now only a small part of the total published material. An experiment in 1974, publishing the proceedings of a Nobel Physics Symposium, led to the formation of a semi-independent journal, Physica Scripta Topical Issues (PSTOP). To date, over 138 volumes of PSTOPs have been published, mostly containing conference proceedings covering a wide range of topics. The annual Nobel Physics Symposium is usually published as one of these volumes. Beginning in 2003, Physica Scripta introduced a new section, Comments on Atomic and Molecular Physics. This has since expanded to five distinct sections of Comments: atomic, molecular and optical physics

  8. A new polystomatid (Monogenea, Polystomatidae) from the mouth of the North American freshwater turtle Pseudemys nelsoni.

    Science.gov (United States)

    Du Preez, Louis H; Van Rooyen, Michelle

    2015-01-01

    Based on material collected from Pseudemys nelsoni (Reptilia: Chelonia: Emydidae) during a parasite survey of the herpetofauna around Gainesville, Florida, USA, Polystomoides nelsoni sp. n. is described as a new polystome species. This parasite was found in the oral and pharyngeal region of the host. In a sample of nine Pseudemys nelsoni, three specimens were found to release polystome eggs. One turtle was euthanized and dissected and found to be infected in the oral region with 19 specimens belonging to an as-yet-unknown Polystomoides. This is only the fifth Polystomoides recorded from the Nearctic realm. This species is distinguished from known species by a combination of characteristics including marginal hooklet morphology, body length and haptor dimensions.

  9. Pharmacokinetic profiles of meloxicam in turtles (Trachemys scripta scripta) after single oral, intracoelomic and intramuscular administrations.

    Science.gov (United States)

    Di Salvo, A; Giorgi, M; Catanzaro, A; Deli, G; della Rocca, G

    2016-02-01

    Meloxicam is an anti-inflammatory and analgesic drug used to treat many pathological conditions in turtles. With the aim to fill the lack of data about its pharmacokinetic in this species, eighteen turtles (Trachemys scripta scripta) were divided in three groups and treated with a single dose of meloxicam (0.2 mg/kg) by intramuscular, intracoelomic and oral route, respectively. At scheduled time points, blood samples were collected and meloxicam concentrations were determined by HPLC. Pharmacokinetic parameters were calculated from the obtained concentration-time curves. After intramuscular treatment, a plasma peak of meloxicam equal to 1590.03 ± 1845.32 ng/mL (mean ± SD) and a Tmax of 1.17 ± 0.45 h were reached, indicating a quick absorption of the drug. The intracoelomic administration brought to the largest AUC (12621.04 ± 6203.79 h*ng/mL) and to a Cmax and a Tmax equal to 1154.52 ± 662.78 ng/mL and 2.82 ± 1.39 h, respectively. Following oral treatment, the plasma concentrations of meloxicam were very low indicating a scarce absorption. Further studies are warranted to determine the effective plasma concentration of meloxicam in turtles and, consequently, the dosage regimen. © 2015 John Wiley & Sons Ltd.

  10. "Scripta" üldpilt on muljetavaldav / Tiina Kolk

    Index Scriptorium Estoniae

    Kolk, Tiina

    2005-01-01

    Rahvusvahelisest köitenäitusest "Scripta manet III" Eesti Tarbekunsti- ja Disainimuuseumis. Osaleb 130 kunstnikku 17 riigist. Näitusega kaasneval konkursil pälvisid Kuldraamatu auhinna eesti kunstnikud Külli Grünbach-Sein, Kaire Olt ja Jaana Päeva

  11. Ecomorphological variation in shell shape of the freshwater turtle Pseudemys concinna inhabiting different aquatic flow regimes.

    Science.gov (United States)

    Rivera, Gabriel

    2008-12-01

    Populations of species that inhabit a range of environments frequently display divergent morphologies that correlate with differences in ecological parameters. The velocity of water flow (i.e., flow velocity) is a critical feature of aquatic environments that has been shown to influence morphology in a broad range of taxa. The focus of this study was to evaluate the relationship between flow velocity and shell morphology for males and females of the semi-aquatic freshwater turtle Pseudemys concinna. For both sexes, the carapace and plastron show significant morphological differences between habitats characterized by slow-flowing (i.e., lentic) and fast-flowing (i.e., lotic) water. In general, the most prominent pattern for both sexes is that the shells of individuals from lotic habitats are more streamlined (small height-to-length ratio) than the shells of individuals from lentic habitats. Of the two shell components (carapace and plastron), the carapace shows greater divergence between habitats, particularly for males. These results are consistent with adaptations to flow velocity, and suggest that variation in shape may be more constrained in females. I also provide empirical evidence for an adaptive benefit of the observed shape change (i.e., drag reduction) and a brief comment on the relative roles of genetic divergence and phenotypic plasticity in generating shape differences observed in this species.

  12. Evaluation of rebound tonometry in red-eared slider turtles (Trachemys scripta elegans).

    Science.gov (United States)

    Delgado, Cherlene; Mans, Christoph; McLellan, Gillian J; Bentley, Ellison; Sladky, Kurt K; Miller, Paul E

    2014-07-01

    To evaluate feasibility and accuracy of intraocular pressure (IOP) measurement by rebound tonometry in adult red-eared slider turtles and determine the effects of manual and chemical restraint on IOP. Seventeen adult red-eared slider turtles. Intraocular pressure was measured with TonoLab® and TonoVet® tonometers in conscious, unrestrained turtles. To evaluate the effects of manual restraint, turtles were restrained by digital pressure on the rostral head or proximal neck. The effect of two chemical restraint protocols (dexmedetomidine, ketamine, midazolam [DKM] and dexmedetomidine, ketamine [DK] subcutaneously) on IOP was evaluated. Triplicate TonoLab® and TonoVet® readings were compared with direct manometry in three ex vivo turtle eyes. TonoLab® correlated better with manometry at IOPs turtles was significantly lower (P turtles. Chemical and manual neck restraint affected IOP. Rostral head restraint had no significant effect on IOP and is, therefore, recommended as the appropriate restraint technique in red-eared slider turtles. TonoLab® measurements estimated actual IOP more accurately, within physiologic range, than measurements obtained using the TonoVet®. © 2013 American College of Veterinary Ophthalmologists.

  13. Information analysis of posterior canal afferents in the turtle, Trachemys scripta elegans.

    Science.gov (United States)

    Rowe, Michael H; Neiman, Alexander B

    2012-01-24

    We have used sinusoidal and band-limited Gaussian noise stimuli along with information measures to characterize the linear and non-linear responses of morpho-physiologically identified posterior canal (PC) afferents and to examine the relationship between mutual information rate and other physiological parameters. Our major findings are: 1) spike generation in most PC afferents is effectively a stochastic renewal process, and spontaneous discharges are fully characterized by their first order statistics; 2) a regular discharge, as measured by normalized coefficient of variation (cv*), reduces intrinsic noise in afferent discharges at frequencies below the mean firing rate; 3) coherence and mutual information rates, calculated from responses to band-limited Gaussian noise, are jointly determined by gain and intrinsic noise (discharge regularity), the two major determinants of signal to noise ratio in the afferent response; 4) measures of optimal non-linear encoding were only moderately greater than optimal linear encoding, indicating that linear stimulus encoding is limited primarily by internal noise rather than by non-linearities; and 5) a leaky integrate and fire model reproduces these results and supports the suggestion that the combination of high discharge regularity and high discharge rates serves to extend the linear encoding range of afferents to higher frequencies. These results provide a framework for future assessments of afferent encoding of signals generated during natural head movements and for comparison with coding strategies used by other sensory systems. This article is part of a Special Issue entitled: Neural Coding. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Specialization for underwater hearing by the tympanic middle ear of the turtle, Trachemys scripta elegans

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J.; Brandt, Christian; Willis, K. L.

    2012-01-01

    Turtles, like other amphibious animals, face a trade-off between terrestrial and aquatic hearing. We used laser vibrometry and auditory brainstem responses to measure their sensitivity to vibration stimuli and to airborne versus underwater sound. Turtles are most sensitive to sound underwater...

  15. RESPONSE OF HATCHLING AND YEARLING TURTLES TO THERMAL GRADIENTS: COMPARISON OF CHELYDRA SERPENTINA AND TRACHEMYS SCRIPTA

    Science.gov (United States)

    In laboratory test, young Chelydra serpentina and Trachemys scripta altered their distribution in the presence of a temperature gradient. Selection of temperatures in the gradient for hatchlings and yearlings showed that body temperature (Tbs) of C. serpentina were lower tha...

  16. Accumulation of coal combustion residues and their immunological effects in the yellow-bellied slider (Trachemys scripta scripta).

    Science.gov (United States)

    Haskins, David L; Hamilton, Matthew T; Jones, Amanda L; Finger, John W; Bringolf, Robert B; Tuberville, Tracey D

    2017-05-01

    Anthropogenic activities such as industrial processes often produce copious amounts of contaminants that have the potential to negatively impact growth, survival, and reproduction of exposed wildlife. Coal combustion residues (CCRs) represent a major source of pollutants globally, resulting in the release of potentially harmful trace elements such as arsenic (As), cadmium (Cd), and selenium (Se) into the environment. In the United States, CCRs are typically stored in aquatic settling basins that may become attractive nuisances to wildlife. Trace element contaminants, such as CCRs, may pose a threat to biota yet little is known about their sublethal effects on reptiles. To assess the effects of CCR exposure in turtles, we sampled 81 yellow-bellied sliders (Trachemys scripta scripta) in 2014-2015 from CCR-contaminated and uncontaminated reference wetlands located on the Savannah River Site (Aiken, SC, USA). Specific aims were to (1) compare the accumulation of trace elements in T. s. scripta claw and blood samples between reference and CCR-contaminated site types, (2) evaluate potential immunological effects of CCRs via bacterial killing assays and phytohaemagglutinin (PHA) assays, and (3) quantify differences in hemogregarine parasite loads between site types. Claw As, Cd, copper (Cu), and Se (all p ≤ 0.001) and blood As, Cu, Se, and strontium (Sr; p ≤ 0.015) were significantly elevated in turtles from CCR-contaminated wetlands compared to turtles from reference wetlands. Turtles from reference wetlands exhibited lower bacterial killing (p = 0.015) abilities than individuals from contaminated sites but neither PHA responses (p = 0.566) nor parasite loads (p = 0.980) differed by site type. Despite relatively high CCR body burdens, sliders did not exhibit apparent impairment of immunological response or parasite load. In addition, the high correlation between claw and blood concentrations within individuals suggests that nonlethal tissue sampling may be

  17. Training and long-term memory of a novel food acquisition task in a turtle (Pseudemys nelsoni).

    Science.gov (United States)

    Davis, Karen M; Burghardt, Gordon M

    2007-06-01

    We developed a shaping procedure for training Florida red-bellied cooters, Pseudemys nelsoni, to dislodge clear plastic bottles to obtain food pellets. The animals were then trained in a 2-choice problem to choose only the bottle containing pellets. All nine turtles learned the task of knocking over bottles for food. For the discrimination task, turtles chose the correct bottle 71% on average. After 2 months (82-84 days), and again after another 7.5 months (228 days) of no interaction with the bottles, turtles were retested and many retained both the response and the discrimination (mean success rates 77-81%), with significant savings in retraining all turtles. The turtles showed two basic response strategies, which changed across time for some individuals. This study demonstrates that turtles can learn and retain a novel skill in a laboratory context.

  18. Histologie comparée des fosses nasales de quelques Tortues marines (Dermochelys coriacea et Chelonia mydas) et d’eaux douces (Emys orbicularis et Pseudemys scripta) (Reptilia, Dermochelyidae, Cheloniidae, Emydidae)

    NARCIS (Netherlands)

    Saint-Girons, H.

    1991-01-01

    Comparative histological studies carried out on the nasal cavity of four species of turtles showed that the sea turtles have a more or less regressed olfactive epithelium compared to that of the Emydidae but that their vomeronasal epithelium is more developed. The location of the vomeronasal

  19. The bionomics of the cottonwood leaf beetle, Chrysomela scripta Fab., on tissue culture hybrid poplars

    Science.gov (United States)

    T.R. Burkot; D.M. Benjamin

    1977-01-01

    Tissue culture methods are applied to poplars of the Aigeiros group in attempts to overcome premature decline thought to be associated with viral infections. Hybrid selections from such cultures outplanted in 1975 at the F. G. Wilson Nursery in Boscobel, Wisconsin subsequently were severely infested by the Cottonwood Leaf Beetle, Chrysomela scripta Fab. Beetle...

  20. [O rzeczach minionych, scripta rerum historicarum annae rutkowska-plachcińska oblata] / Risto Pullat

    Index Scriptorium Estoniae

    Pullat, Raimo, 1935-

    2011-01-01

    Arvustus: O rzeczach minionych, scripta rerum historicarum annae rutkowska-plachcińska oblata. (Pod redakeja Marty Mlynarskiej-Kaletynowej i Jerzego Kruppe. Studia i materaly z historii kultury materialney pod redakeja Jerzego Kruppe). Warszawa, 2006. Sisukast ja mitmekülgsest Anna Rutkowska-Plachcinska juubelikogumikust

  1. Energy budgets and a climate space diagram for the turtle, Chrysemys scripta

    Energy Technology Data Exchange (ETDEWEB)

    Foley, R. E.

    1976-01-01

    Heat energy budgets were computed and a steady state climate space was generated for a 1000 g red-eared turtle (Chrysemys scripta). Evaporative water loss (EWL) was measured from C. scripta at three wind speeds (10-400 cm sec/sup -1/) and at four air temperatures (5 to 35/sup 0/C) in a wind tunnel. EWL increased as air temperature and wind speed increased. Smaller turtles dehydrated at a faster rate than large turtles. Heat transfer by convection was measured from aluminum castings of C. scripta at three temperature differences between casting and air (..delta..T 15/sup 0/, 10/sup 0/ and 5/sup 0/C) for three windspeeds (10 to 400 cm sec/sup -1/). Convective heat transfer coefficients increased as wind speed and ..delta..T increased. Wind speed has a large effect on the shape of the climate space. At high wind speeds, heat loss by evaporation and convection are greatly increased. In still air (10 cm sec/sup -1/), a turtle cannot remain exposed to full sunlight when air temperatures exceed 19/sup 0/C. When wind speed increases to 400 cm sec/sup -1/, the turtle can bask for long periods of time at temperatures as high as 32/sup 0/C. Basking patterns of C. scripta probably shift from a unimodal pattern in the spring to a bimodal pattern in summer and return to a unimodal pattern in fall. Terrestrial activity may be extensive in the spring and fall but is limited during the hot summer months to periods of rainfall. Nesting activities cannot occur around solar noon because increased metabolic heat loading and high solar radiation intensity could cause death.

  2. The Embryonic Transcriptome of the Red-Eared Slider Turtle (Trachemys scripta.

    Directory of Open Access Journals (Sweden)

    Nicholas J Kaplinsky

    Full Text Available The bony shell of the turtle is an evolutionary novelty not found in any other group of animals, however, research into its formation has suggested that it has evolved through modification of conserved developmental mechanisms. Although these mechanisms have been extensively characterized in model organisms, the tools for characterizing them in non-model organisms such as turtles have been limited by a lack of genomic resources. We have used a next generation sequencing approach to generate and assemble a transcriptome from stage 14 and 17 Trachemys scripta embryos, stages during which important events in shell development are known to take place. The transcriptome consists of 231,876 sequences with an N50 of 1,166 bp. GO terms and EC codes were assigned to the 61,643 unique predicted proteins identified in the transcriptome sequences. All major GO categories and metabolic pathways are represented in the transcriptome. Transcriptome sequences were used to amplify several cDNA fragments designed for use as RNA in situ probes. One of these, BMP5, was hybridized to a T. scripta embryo and exhibits both conserved and novel expression patterns. The transcriptome sequences should be of broad use for understanding the evolution and development of the turtle shell and for annotating any future T. scripta genome sequences.

  3. Melanin deposition ruled out as cause of color changes in the red-eared sliders (Trachemys scripta elegans).

    Science.gov (United States)

    Cao, Dainan; Gong, Shiping; Yang, Jiangbo; Li, Weiye; Ge, Yan; Wei, Yufeng

    2018-03-01

    Animal coloration primarily depends on the presence of pigments and the mixing ratio of eumelanin and pheomelanin. The color of red-eared slider's carapace varies with age, from an olive green to a yellow green, and then to a yellow brown in juveniles, generally. The purpose of the present study was to investigate whether this color change is related to the difference in melanin expression. Melanin deposition levels were examined in the carapace, skin, eye and muscle of the three color-types using hematoxylin and eosin staining. Moreover, the full-length coding sequence (CDS) of red-eared slider turtle melanin biosynthesis regulatory genes TYR, TYRP1, MITF and SLC24A5 were cloned, sequenced and quantitatively analyzed. Both histological view of melanin deposition and quantitative real-time PCR test of melanin-regulated gene expressions showed that there are significant differences among different tissues of red-eared slider, but no significant difference among different color-types, indicating that melanin deposition is not associated with ontogenetic color change in the carapace of red-eared slider. This study initially explore the melanin deposition and the mRNA expression of melanin biosynthesis regulatory genes in red-eared slider, which serve as a foundation for further insight into the pigmentation patterns and the mechanism of body color change in turtles. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Pancreatitis associated with the helminth Serpinema microcephalus (Nematoda: Camallanidae) in exotic Red-Eared Slider Turtles (Trachemys scripta elegans)

    Czech Academy of Sciences Publication Activity Database

    Hidalgo-Vila, J.; Martínez-Silvestre, A.; Ribas, Alexis; Casanova, J. C.; Pérez-Santigosa, N.; Díaz-Paniagua, C.

    2011-01-01

    Roč. 47, č. 1 (2011), s. 201-205 ISSN 0090-3558 Institutional research plan: CEZ:AV0Z60930519 Keywords : helminth * invasive exotic turtles * pancreatitis * reptiles Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 1.079, year: 2011 http://www.jwildlifedis.org/cgi/reprint/47/1/201

  5. [Tropical turtles chromosomes: Kinosternon leucostomum, Trachemys scripta and Staurotypus triporcatus (Testudines: Kinosternidae/Emydidae)].

    Science.gov (United States)

    Hernández-Guzmán, Javier; Indy, Jeane Rimber; Yasui, George Shigueki; Arias-Rodriguez, Lenin

    2014-06-01

    Mexico is a biodiverse country in several taxa as reptiles, that include several species of freshwater and marine turtles. Eventhough most of this group species are under protection, Tabasco State has nine native freshwater turtles, like Kinosternon leucostomum, Trachemys scripta and Staurotypus triporcatus that are very important in traditional dishes. This has resulted in a critical level of their populations, together with little biological knowledge for their conservation. Therefore, this study was dedicated to turtle cytogenetics. The study was conducted using the conventional methods for cytogenetics. The results showed the modal diploid and haploid number for K. leucostomum of 2n = 56 (2n = 56+3 microchromosomes "B") and 1n = 28 chromosomes in mitosis and meiosis, respectively. In T. scripta 2n = 50 chromosomes (2n = 50+2 microchromosomes "B") and 1n = 25 chromosomes were also characterized. Whereas in S. triporcatus we only report the 2 = 54 chromosomes (2n = 54+2 microchromosomes "B"). The karyological formula for K. leucostomum was integrated by 12 metacentric-submetacentric chromosomes "msm"/"A"+22 subtelocentric-telocentric chromosomes "stt"/"B"+22 telocentric chromosomes "T"/"C" with fundamental number (FN) of 90 chromosome arms. While T. scripta karyotype was integrated by 32 "msm/"A"+10 "stt"/"B"+8"T/"C" chromosomes, with FN of 92 arms. S. triporcatus karyotype formula was built up by 20 chromosomes "msm"/"A"+34 chromosomes "T"/"C" with FN of 74. The variation in chromosome classification, the fundamental number and the presence of supernumerary microchromosomes "B" in the studied species, were evidence of a particular chromosome cytotypes in Tabasco. We considered that the presence of microchromosomes "B" probably has different origins, and they may be very important as a pattern for the formation or separation of new species. This study also showed the absence of heterologous chromosomes between the females and males karyotypes from the studied

  6. C. elegans chemotaxis assay

    National Research Council Canada - National Science Library

    Margie, Olivia; Palmer, Chris; Chin-Sang, Ian

    2013-01-01

    .... Caenorhabditis elegans has impressive chemotaxis behavior. The premise behind testing the response of the worms to an odorant is to place them in an area and observe the movement evoked in response to an odorant...

  7. Scripta manent?

    Directory of Open Access Journals (Sweden)

    Vallori Rasini

    2014-12-01

    Full Text Available Word belongs to human being; it is a monopoly of his nature. Verbal word contains deep meanings, has symbolic value and makes possible the domain of the world. It is also fluid, transient and frequently allusive. Writing stops the word, makes it durable and sometimes changes it in a rule. Printing press supported writing and his diffusion increases human progress. Digital writing is the contemporary evolution of written communication by computer and cell phone. It is not so permanent as traditional written. Can it preserves historical memory and humanities of man?

  8. Adenosinergic regulation of the cardiovascular system in the red-eared slider Trachemys scripta.

    Science.gov (United States)

    Joyce, William; Wang, Tobias

    2014-08-01

    Few studies have investigated adenosinergic regulation of the cardiovascular system in reptiles. The haemodynamic effect of a bolus intra-arterial adenosine injection (2.5 μM kg⁻¹) was investigated in nine anaesthetised red-eared sliders (Trachemys scripta). Adenosine caused a transient bradycardia, which was accompanied by systemic vasodilatation as evidenced by an increase in systemic flow and a decrease in systemic pressure. Meanwhile, pulmonary flow fell significantly. Both the bradycardia and increase in systemic conductance were significantly attenuated by theophylline (4 mg kg⁻¹), demonstrating an involvement of P₁ receptors. These results suggest that adenosine is likely to play a significant role in reptile cardiovascular physiology. In turtles specifically, adenosinergic regulation may be particularly relevant during periods of apnoea. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Malondialdehyde suppresses cerebral function by breaking homeostasis between excitation and inhibition in turtle Trachemys scripta.

    Directory of Open Access Journals (Sweden)

    Fangxu Li

    Full Text Available The levels of malondialdehyde (MDA are high in the brain during carbonyl stress, such as following daily activities and sleep deprivation. To examine our hypothesis that MDA is one of the major substances in the brain leading to fatigue, the influences of MDA on brain functions and neuronal encodings in red-eared turtle (Trachemys scripta were studied. The intrathecal injections of MDA brought about sleep-like EEG and fatigue-like behaviors in a dose-dependent manner. These changes were found associated with the deterioration of encoding action potentials in cortical neurons. In addition, MDA increased the ratio of γ-aminobutyric acid to glutamate in turtle's brain, as well as the sensitivity of GABAergic neurons to inputs compared to excitatory neurons. Therefore, MDA, as a metabolic product in the brain, may weaken cerebral function during carbonyl stress through breaking the homeostasis between excitatory and inhibitory neurons.

  10. Survival assays using Caenorhabditis elegans.

    Science.gov (United States)

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

    2017-02-01

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

  11. Vasoactivity of hydrogen sulfide in normoxic and anoxic turtles (Trachemys scripta)

    DEFF Research Database (Denmark)

    Stecyk, Jonathan A.W.; Jensen, Nini Skovgaard; Nilsson, Göran E.

    2010-01-01

    , contributes to the increased Rsys of anoxic red-eared slider turtles (Trachemys scripta). Vascular infusion of the H2S donor NaHS in anesthetized turtles at 21°C and fully recovered normoxic turtles at 5°C and 21°C revealed H2S to be a potent vasoconstrictor of the systemic circulation. Likewise, wire...... myography of isolated turtle mesenteric and pulmonary arteries demonstrated H2S to mediate an anoxia-induced constriction. Intriguingly, however, NaHS did not exert vasoconstrictory effects during anoxia (6 h at 21°C; 14 days at 5°C) when plasma H2S concentration, estimated from the colorimetric measurement...... of plasma acid-labile sulfide concentration, likely increased by 3- and 4-fold during anoxia at 21°C, and 5°C, respectively. Yet, blockade of endogenous H2S production by DL-propargylglycine or hydroxylamine (0.44 mmol/kg) partially reversed the decreased systemic conductance (Gsys) exhibited by 5°C anoxic...

  12. 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

  13. Effects of deslorelin acetate on plasma testosterone concentrations in captive yellow-bellied sliders (Trachemys scripta sp.).

    Science.gov (United States)

    Potier, Romain; Monge, Emma; Loucachevsky, Tatiana; Hermes, Robert; Göritz, Frank; Rochel, Daphné; Risi, Emmanuel

    2017-09-01

    In Europe, the yellow-bellied slider (Trachemys scripta sp.) is a non-native species in competition with native freshwater turtles. Research on contraception could be useful to control the captive population. Identifying a method of contraception in chelonians would potentially help to control aggression in other chelonian species. The objective of the current study was to evaluate the effects of a single 4.7-mg deslorelin acetate implant on plasma testosterone concentrations in yellow-bellied sliders (Trachemys scripta sp.). Eleven adult male yellow-bellied sliders were used for the study. Males from the treatment group (n = 6) received a 4.7-mg deslorelin acetate implant, whereas males from the control group (n = 5) did not receive any treatment. All individuals were housed under the same environmental conditions. Testosterone plasma concentrations of the control group and the treatment group were measured at six time points (T0-T6) between April and September. No difference between the control group and the deslorelin treatment group was observed at T0, T2, T3, T4, T5 or T6. However, mean plasma testosterone concentration was significantly higher in the treatment group than in the control group at T1. This suggests that treatment with a 4.7-mg deslorelin acetate implant has a transient stimulatory effect on the anterior pituitary in yellowbellied sliders without a negative feedback on testosterone production. Further studies with a higher dosage of deslorelin acetate are needed to draw conclusions on its contraceptive effect.

  14. Road density not a major driver of Red-eared slider (Trachemys scripta elegans) population demographics in the Lower Rio Grande Valley of Texas

    Science.gov (United States)

    Ivana Mali; Brian E. Dickerson; Donald J. Brown; James R. Dixon; Michael R. J. Forstner

    2013-01-01

    In recent years there have been concerns over the conservation and management of freshwater turtle populations in the state of Texas. In 2008 and 2009, we completed several investigations addressing anthropogenic impacts on freshwater turtles in the Lower Rio Grande Valley (LRGV) of Texas. Here, we use a model selection approach within an information-theoretic...

  15. Role of the trochlear nerve in eye abduction and frontal vision of the red-eared slider turtle (Trachemys scripta elegans).

    Science.gov (United States)

    Dearworth, J R; Ashworth, A L; Kaye, J M; Bednarz, D T; Blaum, J F; Vacca, J M; McNeish, J E; Higgins, K A; Michael, C L; Skrobola, M G; Jones, M S; Ariel, M

    2013-10-15

    Horizontal head rotation evokes significant responses from trochlear motoneurons of turtle that suggests they have a functional role in abduction of the eyes like that in frontal-eyed mammals. The finding is unexpected given that the turtle is generally considered lateral-eyed and assumed to have eye movements instead like that of lateral-eyed mammals, in which innervation of the superior oblique muscle by the trochlear nerve (nIV) produces intorsion, elevation, and adduction (not abduction). Using an isolated turtle head preparation with the brain removed, glass suction electrodes were used to stimulate nIV with trains of current pulses. Eyes were monitored via an infrared camera with the head placed in a gimble to quantify eye rotations and their directions. Stimulations of nIV evoked intorsion, elevation, and abduction. Dissection of the superior oblique muscle identified lines of action and a location of insertion on the eye, which supported kinematics evoked by nIV stimulation. Eye positions in alert behaving turtles with their head extended were compared with that when their heads were retracted in the carapace. When the head was retracted, there was a reduction in interpupillary distance and an increase in binocular overlap. Occlusion of peripheral fields by the carapace forces the turtle to a more frontal-eyed state, perhaps the reason for the action of abduction by the superior oblique muscle. These findings support why trochlear motoneurons in turtle respond in the same way as abducens motoneurons to horizontal rotations, an unusual characteristic of vestibulo-ocular physiology in comparison with other mammalian lateral-eyed species. Copyright © 2013 Wiley Periodicals, Inc.

  16. Cytological evaluation of spermatogenesis and organization of the germinal epithelium in the male slider turtle, Trachemys scripta.

    Science.gov (United States)

    Gribbins, Kevin M; Gist, Daniel H; Congdon, Justin D

    2003-03-01

    The germ cell development in the slider turtle (Trachemys scripta) testis was investigated by viewing the histology of the seminiferous epithelium in plastic sections with a light microscope. Germ cell morphologies in the slider turtle testis were similar to the morphologies of other vertebrate germ cell types. However, the slider turtle seminiferous epithelium contained germ cells that progress through spermatogenesis in a temporal rather than a spatial pattern, resulting in a single spermatogenic event that climaxed with one massive sperm release in November. Mature sperm then are stored within the epididymis until breeding commences in the following spring. The germ cell development strategy in the slider turtle is different from that of other amniotes and is more reminiscent of the developmental strategy found in the anamniotic testis. This temporal progression of germ cells through spermatogenesis within a tubular testis represents a transitional model that may be evolutionarily significant. Copyright 2003 Wiley-Liss, Inc.

  17. Circulating nitric oxide metabolites and cardiovascular changes in the turtle Trachemys scripta during normoxia, anoxia and reoxygenation

    DEFF Research Database (Denmark)

    Jacobsen, Søren B.; Hansen, Marie Niemann; Jensen, Frank Bo

    2012-01-01

    Turtles of the genus Trachemys show a remarkable ability to survive prolonged anoxia. This is achieved by a strong metabolic depression, redistribution of blood flow and high levels of antioxidant defence. To understand whether nitric oxide (NO), a major regulator of vasodilatation and oxygen...... consumption, may be involved in the adaptive response of Trachemys to anoxia, we measured NO metabolites (nitrite, S-nitroso, Fe-nitrosyl and N-nitroso compounds) in the plasma and red blood cells of venous and arterial blood of Trachemys scripta turtles during normoxia and after anoxia (3 h......-nitroso compounds were present at high micromolar levels under normoxia and increased further after anoxia and reoxygenation, suggesting NO generation from nitrite catalysed by deoxygenated haemoglobin, which in turtle had a higher nitrite reductase activity than in hypoxia-intolerant species. Taken together...

  18. The C. elegans eggshell

    Science.gov (United States)

    Stein, Kathryn K.; Golden, Andy

    2017-01-01

    In all animals, oocytes are surrounded by an extracellular matrix upon fertilization. This matrix serves similar purposes in each animal. It functions to mediate sperm binding, to prevent polyspermy, to control the chemical environment of the embryo, and to provide physical protection to the embryo as it developes. The synthesis of the C. elegans matrix, or eggshell, begins when the oocyte enters the spermatheca and is fertilized by a single sperm. The process of eggshell synthesis is thought to take place during the completion of the maternal meiotic divisions such that the multi-layered eggshell is completed by anaphase II. The synthesis of the eggshell occurs in a hierarchical pattern such that the outermost layers are synthesized first in order to capture and retain the innermost layers as they form. Recent studies have revealed that the lipid-rich permeability barrier is distinct from the outer trilaminar eggshell. These new findings alter our previous understanding of the eggshell. This chapter aims to define each of the eggshell layers and the molecules that are known to play significant roles in their formation. PMID:26715360

  19. The glia of Caenorhabditis elegans.

    Science.gov (United States)

    Oikonomou, Grigorios; Shaham, Shai

    2011-09-01

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

  20. Proteomic analysis of Caenorhabditis elegans

    Science.gov (United States)

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

  1. 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

  2. Imaging metals in Caenorhabditis elegans.

    Science.gov (United States)

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

    2017-04-19

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

  3. 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

  4. "Scripta manent" on meie regioonis ainulaadne üritus / Sirje Kriisa, Lennart Mänd, Rene Haljasmäe...[jt.] ; üles kirjutanud Reet Varblane

    Index Scriptorium Estoniae

    2005-01-01

    Kuni 2. X Eesti Tarbekunsti- ja Disainimuuseumis avatud rahvusvahelisest köitekunstinäitusest "Scripta manent III. Maailma parim asi". Köitekunstist kõnelesid näituse korralduskomitee liikmed. Žürii koosseis. Kuldraamatud pälvisid Külli Grünbach-Sein, Kaire Olt ja Jaana Päeva. Näituse korralduskomitees ka Tulvi-Hanneli Turo ja Rene Haljasmäe TLÜARist

  5. Potential Pathogens in the Environment: Isolation, Enumeration, and Identification of Seven Genera of Intestinal Bacteria Associated with Small Green Pet Turtles1

    Science.gov (United States)

    McCoy, R. H.; Seidler, Ramon J.

    1973-01-01

    Bacteriological analyses were performed on fecal swabs and the aquarium water of 27 individually purchased specimens of the small green pet turtle, Pseudemys scripta elegans. Representatives of Aeromonas, Citrobacter, Enterobacter, Klebsiella, Proteus, Salmonella, and Serratia were isolated. Enterobacter, Klebsiella, and Salmonella were encountered in 20% or more of the specimens, whereas Aeromonas was isolated from 63%. Klebsiella pneumoniae counts ranged from 103 to 104 per milliliter of aquarium water, whereas Aeromonas routinely exceeded 104 per milliliter. Aeromonas cultures from turtles were identical to 7 human isolates in some 29 biochemical tests. On the basis of our findings, we question whether the Salmonella-free certification program alone is sufficient to render these reptiles as safe pets. PMID:4572984

  6. Los cromosomas de las tortugas tropicales: Kinosternon leucostomum, Trachemys scripta y Staurotypus triporcatus (Testudines: Kinosternidae/Emydidae

    Directory of Open Access Journals (Sweden)

    Javier Hernández-Guzmán

    2014-08-01

    Full Text Available México es un país biodiverso en varios grupos taxonómicos incluyendo a los reptiles, por ello en el país existen varias especies de tortugas dulceacuícolas y marinas. Las especies que integran dicho grupo se encuentran dentro del listado de especies sujetas a protección. El estado de Tabasco cuenta con nueve especies de tortugas de agua dulce, de las cuales Kinosternon leucostomum, Trachemys scripta y Staurotypus triporcatus son de las más importantes dentro de la tradición culinaria, hecho que las ha llevado a niveles críticos en sus poblaciones; aunado al poco conocimiento biológico que sobre dichas especies existe para conservarlas. Por lo anterior, el presente estudio de citogenética es el primero en tortugas de agua dulce en la región. El estudio se realizó, empleando el método convencional de citogenética. Los resultados muestran, el número modal diploide y haploide de K. leucostomum de 2n=56 (2n=56+3 microcromosomas “B” y 1n=28 cromosomas 686 en mitosis y meiosis, respectivamente. En T. scripta de 2n=50 cromosomas (2n=50+2 microcromosomas “B” y 1n=25 cromosomas. Mientras que en S. triporcatus solo se reporta el 2n=54 cromosomas (2n=54+2 microcromosomas “B”. La fórmula cromosómica en K. leucostomum, fue de 12 cromosomas metacéntricos submetacéntricos “msm”/“A”+22 cromosomas subtelocéntricos-telocéntricos “stt”/“B”+22 cromosomas telocéntricos “T”/“C”, con número fundamental (NF de 90 brazos cromosómicos. En T. scripta fue de 32 cromosomas “msm”/“A”+10 cromosomas “stt”/“B”+8 cromosomas “T”/“C”, con NF de 92 y en S. triporcatus 20 cromosomas “msm”/“A”+34 cromosomas “T”/“C” con NF de 74. La variación en la clasificación cromosómica, el número fundamental y la presencia de microcromosomas “B” supernumerarios en las tres especies, son evidencia de citotipos cromosómicos particulares de las tortugas de Tabasco. Se argumenta que la

  7. Western Blot Analysis of C. elegans Proteins.

    Science.gov (United States)

    Jeong, Dae-Eun; Lee, Yujin; Lee, Seung-Jae V

    2018-01-01

    C. elegans has been widely used as a model organism for basic biological research and is particularly amenable for molecular genetic studies using a broad repertoire of techniques. Biochemical approaches, including Western blot analysis, have emerged as a powerful tool in C. elegans biology for understanding molecular mechanisms that link genotypes to phenotypes. Here, we provide a protocol for Western blot analysis using protein extracts obtained from C. elegans samples.

  8. Melanoblast development coincides with the late emerging cells from the dorsal neural tube in turtle Trachemys scripta.

    Science.gov (United States)

    Rice, Ritva; Cebra-Thomas, Judith; Haugas, Maarja; Partanen, Juha; Rice, David P C; Gilbert, Scott F

    2017-09-21

    Ectothermal reptiles have internal pigmentation, which is not seen in endothermal birds and mammals. Here we show that the development of the dorsal neural tube-derived melanoblasts in turtle Trachemys scripta is regulated by similar mechanisms as in other amniotes, but significantly later in development, during the second phase of turtle trunk neural crest emigration. The development of melanoblasts coincided with a morphological change in the dorsal neural tube between stages mature G15 and G16. The melanoblasts delaminated and gathered in the carapacial staging area above the neural tube at G16, and differentiated into pigment-forming melanocytes during in vitro culture. The Mitf-positive melanoblasts were not restricted to the dorsolateral pathway as in birds and mammals but were also present medially through the somites similarly to ectothermal anamniotes. This matched a lack of environmental barrier dorsal and lateral to neural tube and the somites that is normally formed by PNA-binding proteins that block entry to medial pathways. PNA-binding proteins may also participate in the patterning of the carapacial pigmentation as both the migratory neural crest cells and pigment localized only to PNA-free areas.

  9. Infection status of the estuarine turtles Kinosternon integrum and Trachemys scripta with Gnathostoma binucleatum in Sinaloa, Mexico Estado de la infección con Gnathostoma binucleatum de las tortugas estuarinas Kinosternon integrum y Trachemys scripta en Sinaloa, México

    Directory of Open Access Journals (Sweden)

    Sylvia Páz Díaz-Camacho

    2010-08-01

    Full Text Available Human gnathostomosis, a serious public health issue in Mexico, is endemic to Sinaloa. The disease is mainly caused by consumption of the raw meat of freshwater or estuarine fishes infected with the advanced third stage larvae (AL3 of Gnathostoma binucleatum. In the present study, we examined estuarine turtles with a sample consisting of 23 Trachemys scripta and 5 Kinosternon integrum from Sinaloa, Mexico for the presence of Gnathostoma larvae; such examination was made by the pressing method of skeletal muscles between 2 glass plates. The results showed that both turtles harbored G. binucleatum AL3; identification was achieved by morphology and also by PCR/sequencing of the ITS2 region of ribosomal DNA of the larvae. Infection prevalence was higher for K. integrum (80% than for T. scripta (69.6%, but heavy infection (> 10 AL3/turtle was observed in the larger sized individuals of T. scripta. Consumption of the raw meat of these turtles represents a risk to acquire the disease.La gnathostomosis humana, un serio problema de salud pública en México, es endémica de Sinaloa. La enfermedad es principalmente ocasionada por el consumo de carne cruda de pescado de agua dulce o salobre infectado con larvas del tercer estadio avanzado (AL3 de Gnathostoma binucleatum. En la presente investigación, se examinaron tortugas estuarinas, 23 Trachemys scripta y 5 Kinosternon integrum, de Sinaloa, México para identificar la presencia de larvas de Gnathostoma; para ello se utilizó el método de compresión del tejido muscular entre 2 placas de vidrio. Los resultados mostraron que ambas especies de tortugas son hospederas de larvas AL3 de G. binucleatum; la identificación específica se basó en la morfología y composición molecular (por PCR/secuenciación de la región ribosomal ITS2 del DNA de las larvas. La prevalencia de la infección fue mayor en K. integrum (80% que en T. scripta (69.6%, pero la intensidad fue más alta (> 10 AL3/tortuga en las

  10. The C. elegans model in toxicity testing.

    Science.gov (United States)

    Hunt, Piper Reid

    2017-01-01

    Caenorhabditis elegans is a small nematode that can be maintained at low cost and handled using standard in vitro techniques. Unlike toxicity testing using cell cultures, C. elegans toxicity assays provide data from a whole animal with intact and metabolically active digestive, reproductive, endocrine, sensory and neuromuscular systems. Toxicity ranking screens in C. elegans have repeatedly been shown to be as predictive of rat LD50 ranking as mouse LD50 ranking. Additionally, many instances of conservation of mode of toxic action have been noted between C. elegans and mammals. These consistent correlations make the case for inclusion of C. elegans assays in early safety testing and as one component in tiered or integrated toxicity testing strategies, but do not indicate that nematodes alone can replace data from mammals for hazard evaluation. As with cell cultures, good C. elegans culture practice (GCeCP) is essential for reliable results. This article reviews C. elegans use in various toxicity assays, the C. elegans model's strengths and limitations for use in predictive toxicology, and GCeCP. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Journal of Applied Toxicology published by John Wiley & Sons Ltd. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Journal of Applied Toxicology published by John Wiley & Sons Ltd.

  11. Forelimb kinematics and motor patterns of the slider turtle (Trachemys scripta) during swimming and walking: shared and novel strategies for meeting locomotor demands of water and land.

    Science.gov (United States)

    Rivera, Angela R V; Blob, Richard W

    2010-10-15

    Turtles use their limbs during both aquatic and terrestrial locomotion, but water and land impose dramatically different physical requirements. How must musculoskeletal function be adjusted to produce locomotion through such physically disparate habitats? We addressed this question by quantifying forelimb kinematics and muscle activity during aquatic and terrestrial locomotion in a generalized freshwater turtle, the red-eared slider (Trachemys scripta), using digital high-speed video and electromyography (EMG). Comparisons of our forelimb data to previously collected data from the slider hindlimb allow us to test whether limb muscles with similar functional roles show qualitatively similar modulations of activity across habitats. The different functional demands of water and air lead to a prediction that muscle activity for limb protractors (e.g. latissimus dorsi and deltoid for the forelimb) should be greater during swimming than during walking, and activity in retractors (e.g. coracobrachialis and pectoralis for the forelimb) should be greater during walking than during swimming. Differences between aquatic and terrestrial forelimb movements are reflected in temporal modulation of muscle activity bursts between environments, and in some cases the number of EMG bursts as well. Although patterns of modulation between water and land are similar between the fore- and hindlimb in T. scripta for propulsive phase muscles (retractors), we did not find support for the predicted pattern of intensity modulation, suggesting that the functional demands of the locomotor medium alone do not dictate differences in intensity of muscle activity across habitats.

  12. C. elegans outside the Petri dish

    Science.gov (United States)

    Frézal, Lise; Félix, Marie-Anne

    2015-01-01

    The roundworm Caenorhabditis elegans has risen to the status of a top model organism for biological research in the last fifty years. Among laboratory animals, this tiny nematode is one of the simplest and easiest organisms to handle. And its life outside the laboratory is beginning to be unveiled. Like other model organisms, C. elegans has a boom-and-bust lifestyle. It feasts on ephemeral bacterial blooms in decomposing fruits and stems. After resource depletion, its young larvae enter a migratory diapause stage, called the dauer. Organisms known to be associated with C. elegans include migration vectors (such as snails, slugs and isopods) and pathogens (such as microsporidia, fungi, bacteria and viruses). By deepening our understanding of the natural history of C. elegans, we establish a broader context and improved tools for studying its biology. DOI: http://dx.doi.org/10.7554/eLife.05849.001 PMID:25822066

  13. 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...

  14. Molecular mechanisms of Caenorhabditis elegans - Bacillus interactions

    OpenAIRE

    Iatsenko, Igor

    2014-01-01

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

  15. Dietary choice behavior in Caenorhabditis elegans

    OpenAIRE

    Shtonda, Boris Borisovich; Avery, Leon

    2006-01-01

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

  16. Forward and reverse mutagenesis in C. elegans.

    Science.gov (United States)

    Kutscher, Lena M; Shaham, Shai

    2014-01-17

    Mutagenesis drives natural selection. In the lab, mutations allow gene function to be deciphered. C. elegans is highly amendable to functional genetics because of its short generation time, ease of use, and wealth of available gene-alteration techniques. Here we provide an overview of historical and contemporary methods for mutagenesis in C. elegans, and discuss principles and strategies for forward (genome-wide mutagenesis) and reverse (target-selected and gene-specific mutagenesis) genetic studies in this animal.

  17. Characterization of brevetoxin (PbTx-3) exposure in neurons of the anoxia-tolerant freshwater turtle (Trachemys scripta).

    Science.gov (United States)

    Cocilova, Courtney C; Milton, Sarah L

    2016-11-01

    Harmful algal blooms are increasing in frequency and extent worldwide and occur nearly annually off the west coast of Florida where they affect both humans and wildlife. The dinoflagellate Karenia brevis is a key organism in Florida red tides that produces a suite of potent neurotoxins collectively referred to as the brevetoxins (PbTx). Brevetoxins bind to and open voltage gated sodium channels (VGSC), increasing cell permeability in excitable cells and depolarizing nerve and muscle tissue. Exposed animals may thus show muscular and neurological symptoms including head bobbing, muscle twitching, paralysis, and coma; large HABs can result in significant morbidity and mortality of marine life, including fish, birds, marine mammals, and sea turtles. Brevetoxicosis however is difficult to treat in endangered sea turtles as the physiological impacts have not been investigated and the magnitude and duration of brevetoxin exposure are generally unknown. In this study we used the freshwater turtle Trachemys scripta as a model organism to investigate the effects of the specific brevetoxin PbTx-3 in the turtle brain. Primary turtle neuronal cell cultures were exposed to a range of PbTx-3 concentrations to determine excitotoxicity. Agonists and antagonists of voltage-gated sodium channels and downstream targets were utilized to confirm the toxin's mode of action. We found that turtle neurons are highly resistant to PbTx-3; while cell viability decreased in a dose dependent manner across PbTx-3 concentrations of 100-2000nM, the EC50 was significantly higher than has been reported in mammalian neurons. PbTx-3 exposure resulted in significant Ca2+ influx, which could be fully abrogated by the VGSC antagonist tetrodotoxin, NMDA receptor blocker MK-801, and tetanus toxin, indicating that the mode of action in turtle neurons is the same as in mammalian cells. As both turtle and mammalian VGSCs have a high affinity for PbTx-3, we suggest that the high resistance of the turtle neuron

  18. Cancer models in C. elegans

    Science.gov (United States)

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

    2013-01-01

    Although now dogma, the idea that non-vertebrate 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. PMID:20175192

  19. pHj, contractility and Ca-balance under hypercapnic acidosis in the myocardium of different vertebrate species

    DEFF Research Database (Denmark)

    Gesser, H; Bonefeld-Jørgensen, Eva Cecilie

    1982-01-01

    The influence of hypercapnic acidosis upon the heart was examined in four vertebrate species. The CO2 in the tissue bath was increased from 2.7 to 15% at 12 degrees C for flounder (Platichthys flesus) and cod (Gadus morhua) and from 3 to 13% at 22 degrees C for turtle (Pseudemys scripta) and rain......The influence of hypercapnic acidosis upon the heart was examined in four vertebrate species. The CO2 in the tissue bath was increased from 2.7 to 15% at 12 degrees C for flounder (Platichthys flesus) and cod (Gadus morhua) and from 3 to 13% at 22 degrees C for turtle (Pseudemys scripta...

  20. Feed transition in larval rearing of bocudo, Steindachneridion scripta (Pisces, Pimelodidae, using Artemia spp. nauplii and artificial diet Transição alimentar na larvicultura do bocudo, Steindachneridion scripta (Pisces, Pimelodidae, com o uso de náuplios de Artemia spp. e dieta artificial

    Directory of Open Access Journals (Sweden)

    W.B. Adamante

    2007-10-01

    Full Text Available Feed transition of Steindachneridion scripta larvae was investigated using seven treatments in which the reference diet, Artemia spp. nauplii, was totally substituted for a 56% crude protein artificial diet in two-day intervals. Initially, all treatments were fed with Artemia spp. nauplii and, subsequently, during the transition period, feed was equally composed by Artemia sp. nauplii and artificial diet. Everyday, one of the treatments began the feed transition, which was implemented between the second and the eighth days of culturing. Two treatments were used as control: one exclusively fed Artemia spp. nauplii and another only with artificial diet. Total weight, total length, and survival rate were not influenced by the day in which feed transition was implemented (P>0.05, and their mean values (± SD were 31.1±25.0mg, 13.3±1.5mm and 58.8±12.0%, respectively. This suggests that Steindachneridion scripta larvae adapted well the transition to artificial diet.A transição alimentar de larvas de Steindachneridion scripta foi investigada utilizando-se sete tratamentos, nos quais a dieta básica, composta por náuplios de Artemia spp., foi integralmente substituída, em intervalo de dois dias, por uma dieta artificial contendo 56% de proteína bruta. Inicialmente, todos os tratamentos receberam náuplios de Artemia spp. No período de transição alimentar, metade da alimentação foi formada por náuplios de Artemia spp. e metade por dieta artificial. A cada dia, um dos tratamentos entrou na fase de transição, que foi implementada entre o segundo e o oitavo dia de cultivo. Utilizaram-se dois tratamentos como controle; em um as larvas foram alimentadas, exclusivamente, com náuplios de Artemia spp. e em outro, somente, com dieta artificial. Peso total, comprimento total e sobrevivência não foram influenciados pelo dia de implantação da transição alimentar (P>0,05 e, apresentaram valores médios iguais a (± desvio padrão 31,1±25,0mg

  1. 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.

  2. Screening for bioactivity of Mutinus elegans extracts

    Science.gov (United States)

    Gajendiran, A.; Cyriac, RE; Abraham, J.

    2017-11-01

    Mutinus elegans is a species of fungi that is commonly called as Elegant Stinkhorn. The aim of this study was to screen the crude extracts of the fungus for phytochemical analysis, antimicrobial activity, antioxidant assay and anticancer activity. Extraction of the fungal sample in Soxhlet apparatus was done with n-hexane and methanol as the solvent. Stock solutions of the crude methanol extract were prepared and used for microbiological assay. Thin layer chromatography was performed in order to determine the number of active components in n-hexane, and methanol solvent system for the fungus Mutinus elegans. Further, antioxidant assay was performed using DPPH radical scavenging assay. The fungal sample was then tested for cytotoxicity assay against MG63 osteosarcoma cell lines. The antimicrobial assay of Mutinus elegans extract exhibited activity against five pathogens. The zone of inhibition was measured with respect to standard antibiotics. Gas chromatography and Mass spectrometry (GC/MS analysis), revealed the presence of dibromo-tetradecan-1-ol-acetate, 2-myristynoyl-glycinamide, fumaric acid, and cyclohexylmethyldecyl ester compounds were presented in methanol and n-hexane extract of Mutinus elegans. The present study concludes the presence of bioactive compound in the extract which exhibited antimicrobial and antioxidant activity in Mutinus elegans.

  3. Cell Death in C. elegans Development.

    Science.gov (United States)

    Malin, Jennifer Zuckerman; Shaham, Shai

    2015-01-01

    Cell death is a common and important feature of animal development, and cell death defects underlie many human disease states. The nematode Caenorhabditis elegans has proven fertile ground for uncovering molecular and cellular processes controlling programmed cell death. A core pathway consisting of the conserved proteins EGL-1/BH3-only, CED-9/BCL2, CED-4/APAF1, and CED-3/caspase promotes most cell death in the nematode, and a conserved set of proteins ensures the engulfment and degradation of dying cells. Multiple regulatory pathways control cell death onset in C. elegans, and many reveal similarities with tumor formation pathways in mammals, supporting the idea that cell death plays key roles in malignant progression. Nonetheless, a number of observations suggest that our understanding of developmental cell death in C. elegans is incomplete. The interaction between dying and engulfing cells seems to be more complex than originally appreciated, and it appears that key aspects of cell death initiation are not fully understood. It has also become apparent that the conserved apoptotic pathway is dispensable for the demise of the C. elegans linker cell, leading to the discovery of a previously unexplored gene program promoting cell death. Here, we review studies that formed the foundation of cell death research in C. elegans and describe new observations that expand, and in some cases remodel, this edifice. We raise the possibility that, in some cells, more than one death program may be needed to ensure cell death fidelity. © 2015 Elsevier Inc. All rights reserved.

  4. Cell Biology of the Caenorhabditis elegans Nucleus.

    Science.gov (United States)

    Cohen-Fix, Orna; Askjaer, Peter

    2017-01-01

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

  5. 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.

  6. Hemoglobin polymerization via disulfide bond formation in the hypoxia-tolerant turtle Trachemys scripta: implications for antioxidant defense and O2 transport

    DEFF Research Database (Denmark)

    Petersen, Asbjørn Graver; Petersen, Steen Vang; Frische, Sebastian

    2018-01-01

    The ability of many reptilian hemoglobins (Hbs) to form high-molecular weight polymers, albeit known for decades, has not been investigated in detail. Given that turtle Hbs often contain a high number of cysteine (Cys), potentially contributing to the red blood cell defense against reactive oxygen...... species, we have examined whether polymerization of Hb could occur via intermolecular disulfide bonds in red blood cells of freshwater turtle Trachemys scripta, a species that is highly tolerant of hypoxia and oxidative stress. We find that one of the two Hb isoforms of the hemolysate, HbA, is prone......A of HbA is a key element of the antioxidant capacity of turtle red blood cells....

  7. Metabolism of naphthalene by Cunninghamella elegans.

    Science.gov (United States)

    Cerniglia, C E; Gibson, D T

    1977-01-01

    Cunninghamella elegans grown on Sabouraud dextrose broth in the presence of naphthalene produced six metabolites. Each product was isolated and identified by conventional chemical techniques. The major metabolites were 1-naphthol (67.9%) and 4-hydroxy-1-tetralone (16.7%). Minor products isolated were 1,4-naphthoquinone (2.8%), 1,2-naphthoquinone (0.2%), 2-naphthol (6.3%), and trans-1,2-dihydroxy-1,2-dihydronaphthalene (5.3%). C. elegans oxidized both 1-naphthol and 1,4-naphthoquinone to 4-hydroxy-1-tetralone. The results suggest that C. elegans oxidizes naphthalene by a sequence of reactions similar to those reported for the mammalian metabolism of this hydrocarbon. PMID:921262

  8. Biotransformation of fluorobiphenyl by Cunninghamella elegans.

    Science.gov (United States)

    Amadio, Jessica; Murphy, Cormac D

    2010-03-01

    The fungus Cunninghamella elegans is a useful model of human catabolism of xenobiotics. In this paper, the biotransformation of fluorinated biphenyls by C. elegans was investigated by analysis of the culture supernatants with a variety of analytical techniques. 4-Fluorobiphenyl was principally transformed to 4-fluoro-4'-hydroxybiphenyl, but other mono- and dihydroxylated compounds were detected in organic extracts by gas chromatography-mass spectrometry. Additionally, fluorinated water-soluble products were detected by (19)F NMR and were identified as sulphate and beta-glucuronide conjugates. Other fluorobiphenyls (2-fluoro-, 4,4'-difluoro- and 2,3,4,5,6-pentafluoro-biphenyl) were catabolised by C. elegans, yielding mono- and dihydroxylated products, but phase II metabolites were detected from 4,4'-difluorobiphenyl only.

  9. Biotransformation of mirtazapine by Cunninghamella elegans.

    Science.gov (United States)

    Moody, Joanna D; Freeman, James P; Fu, Peter P; Cerniglia, Carl E

    2002-11-01

    The fungus Cunninghamella elegans was used as a microbial model of mammalian metabolism to biotransform the tetracyclic antidepressant drug mirtazapine, which is manufactured as a racemic mixture of R(-)- and S(+)-enantiomers. In 168 h, C. elegans transformed 91% of the drug into the following seven metabolites: 8-hydroxymirtazapine, N-desmethyl-8-hydroxymirtazapine, N-desmethylmirtazapine, 13-hydroxymirtazapine, mirtazapine N-oxide, 12-hydroxymirtazapine, and N-desmethyl-13-hydroxymirtazapine. Circular dichroism spectral analysis of unused mirtazapine indicated that it was slightly enriched with the R(-)-enantiomer. When the fungus was treated with the optically pure forms of the drug, the S(+)-enantiomer produced all seven metabolites whereas the R(-)-enantiomer produced only 8-hydroxymirtazapine, N-desmethyl-8-hydroxymirtazapine, N-desmethylmirtazapine, and mirtazapine N-oxide. C. elegans produced five mammalian and two novel metabolites and is therefore a suitable microbial model for mirtazapine metabolism.

  10. Metabolism of naphthalene by Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    Cerniglia, C.E.; Gibson, D.T.

    1977-10-01

    Cunninghamella elegans grown on Sabouraud dextrose broth in the presence of naphthalene produced six metabolites. Each product was isolated and identified by conventional chemical technique. The major metabolites were 1-naphthol (67.9 percent) and 4-hydroxy-1-tetralone (16.7 percent). Minor products isolated were 1,4-naphthoquinone (2.8 percent), 1,2-naphthoquinone (0.2 percent), 2-naphthol (6.3 percent), and trans-1,2-dihydroxy-1,2-dihydronaphthalene (5.3 percent). C. elegans oxidized both 1-naphthol and 1,4-naphthoquinone to 4-hydroxy-1-tetralone. The results suggest that C. elegans oxidizes naphthalene by a sequence of reactions similar to those reported for the mammalian metabolism of this hydrocarbon.

  11. The mevalonate pathway in C. elegans.

    Science.gov (United States)

    Rauthan, Manish; Pilon, Marc

    2011-12-28

    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.

  12. Microbial transformation of mestranol by Cunninghamella elegans.

    Science.gov (United States)

    Choudhary, Muhammad Iqbal; Musharraf, Syed Ghulam; Siddiqui, Zafar Ali; Khan, Naik Tameen; Ali, Rahat Azhar; Ur-Rahman, Atta

    2005-08-01

    The microbial transformation of an oral contraceptive, mestranol (1) by Cunninghamella elegans yielded two hydroxylated metabolites, 6beta-hydroxymestranol (2) and 6beta,12beta-dihydroxymestranol (3). Metabolite 3 was found to be a new compound. These metabolites were structurally characterized on the basis of spectroscopic techniques.

  13. Sulfation of naringenin by Cunninghamella elegans.

    Science.gov (United States)

    Ibrahim, A R

    2000-01-01

    A new flavonoid sulfate, naringenin-7-sulfate, was obtained by fermentation of naringenin using the fungus Cunninghamella elegans NRRL 1392 in 23% yield. Structural elucidation of the metabolite was achieved using EIMS, UV, IR, 1D and 2D NMR spectroscopy beside acid and enzyme hydrolyses.

  14. Fungal transformation of fluoranthene. [Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Characterization of the C. elegans erlin homologue

    Directory of Open Access Journals (Sweden)

    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

  16. 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......-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....

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

    Science.gov (United States)

    Ganner, Athina; Neumann-Haefelin, Elke

    2017-07-01

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

  18. Sampling and Isolation of C. elegans from the Natural Habitat.

    Science.gov (United States)

    Poullet, Nausicaa; Braendle, Christian

    2015-01-01

    Wild populations of the model organism C. elegans allow characterization of natural genetic variation underlying diverse phenotypic traits. Here we provide a simple protocol on how to sample and rapidly identify C. elegans wild isolates. We outline how to find suitable habitats and organic substrates, followed by describing isolation and identification of C. elegans live cultures based on easily recognizable morphological characteristics, molecular barcodes and/or mating tests. This protocol uses standard laboratory equipment and requires no prior knowledge of C. elegans biology.

  19. Structural properties of the Caenorhabditis elegans neuronal network

    National Research Council Canada - National Science Library

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

    2011-01-01

    .... Even for Caenorhabditis elegans, whose neuronal network is relatively small and stereotypical from animal to animal, published wiring diagrams are neither accurate nor complete and self-consistent...

  20. 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. Copyright © 2015 John Wiley & Sons, Inc.

  1. 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.

  2. Biotransformation of furanocoumarins by Cunninghamella elegans

    OpenAIRE

    Attia, Ghada Ismail El-shahat Ali; Kamillia A. Abou-El-seoud; Ibrahim, Abdel-Rahim Sayed

    2015-01-01

    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 spe...

  3. Microbial transformation of dehydroandrographolide by Cunninghamella elegans.

    Science.gov (United States)

    Xin, Xiu-Lan; Ma, Xiao-Chi; Zhang, Bao-Jing; Su, Dong-Hai; Wu, Zhi-Ming; Wang, Xiao-Jie; Li, Xiao-Yan; Yuan, Qi-Peng

    2009-01-01

    The biotransformation of dehydroandrographolide (1) by Cunninghamella elegans was performed and four transformed products were obtained. Based on their extensive spectral data, the structures of these metabolites were identified as 3-oxo-dehydroandrographolide (2), 3-oxo-2beta-hydroxy-dehydroandrographolide (3), 3-oxo-8beta,17alpha-epoxydehydroandrographolide (4), 3,19-dihydroxy-7,11,13-ent-labdatrien-15,16-olide (5), respectively. Among them, products 3-5 are new compounds.

  4. Biotransformation of cinobufagin by Cunninghamella elegans.

    Science.gov (United States)

    Qiao, Li; Zhou, Yu-Zhi; Qi, Xiu-Lan; Lin, Li-Hong; Chen, Huan; Pang, Li-Yan; Pei, Yue-Hu

    2007-04-01

    Cunninghamella elegans has been employed for the biotransformation of cinobufagin to afford 5 metabolites. The structures of the transformation products have been characterized as 12alpha-hydroxybufagin, 11alpha-hydroxybufagin, 12beta-hydroxy-desacetylcinobufagin, 3-oxo-12alpha-hydroxybufagin and 12beta-hydroxybufagin. Products 12alpha-hydroxybufagin and 11alpha-hydroxybufagin are new compounds. In vitro both the biotransformation products and cinobufagin all showed cytotoxic activities against HeLa cells.

  5. Transformation of Amoxapine by Cunninghamella elegans

    OpenAIRE

    Moody, Joanna D.; Zhang, Donglu; Heinze, Thomas M.; Cerniglia, Carl E.

    2000-01-01

    We examined Cunninghamella elegans to determine its ability to transform amoxapine, a tricyclic antidepressant belonging to the dibenzoxazepine class of drugs. Approximately 57% of the exogenous amoxapine was metabolized to three metabolites that were isolated by high-performance liquid chromatography and were identified by nuclear magnetic resonance and mass spectrometry as 7-hydroxyamoxapine (48%), N-formyl-7-hydroxyamoxapine (31%), and N-formylamoxapine (21%). 7-Hydroxyamoxapine, a mammali...

  6. 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.

  7. The Natural Biotic Environment of Caenorhabditis elegans

    Science.gov (United States)

    Schulenburg, Hinrich; Félix, Marie-Anne

    2017-01-01

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

  8. 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

  9. Programmed Cell Death During Caenorhabditis elegans Development

    Science.gov (United States)

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

    2016-01-01

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

  10. Programmed Cell Death During Caenorhabditis elegans Development.

    Science.gov (United States)

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

    2016-08-01

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

  11. Nucleotide Excision Repair in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Hannes Lans

    2011-01-01

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

  12. 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

  13. 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.

  14. Pacific capsular Myrtaceae 5. The Metrosideros Complex: M. elegans Group

    NARCIS (Netherlands)

    Dawson, J.W.

    1972-01-01

    The species at present known as Metrosideros elegans was the basis for Ballardia Montr., Mem. Acad. Lyon 10 (1860) 204. The later described species of the M. elegans group were placed in Metrosideros Banks ex Gaertn., Fruct. I (1788) 170, t. 34, and Beauvisage (1901) finally sank Ballardia in

  15. 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

  16. 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.

  17. 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...

  18. 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...

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

    Science.gov (United States)

    Niwa, Shinsuke

    2017-10-18

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

  20. Effect of electromagnetic nanopulses on C. elegans fertility.

    Science.gov (United States)

    Bojjawar, Tripura; Jalari, Madan; Aamodt, Eric; Ware, Matthew F; Haynie, Donald T

    2006-10-01

    Electromagnetic nanopulse exposure results in decreased fertility of C. elegans, a well studied, multicellar organism. Experiments indicate that this effect is unlikely to be due to heating. Instead, nanopulses interfere with fertilization or development by an as yet undetermined mechanism. Study of nanopulse exposure of C. elegans could help to understand more generally how living organisms interact with electromagnetic fields.

  1. Biotransformation of furanocoumarins by Cunninghamella elegans

    Directory of Open Access Journals (Sweden)

    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.

  2. Axon regeneration in C.elegans

    OpenAIRE

    Radvilas, Vaclovas

    2012-01-01

    [ANGLÈS] There exist many illnesses like Alzheimer's disease and stroke or brain injuries that due to degeneration of the nervous system people can not have normal life anymore. This is a consequence of neuron damage which can not recover or regenerate after being severed in adult mammalian brain and spinal cord. On the other hand, there are examples in nature like Caenorhabditis elegans round worm, zebrafish or even mice that their nervous system can recuperate. The aim of this thesis is to ...

  3. Transformation of amoxapine by Cunninghamella elegans.

    Science.gov (United States)

    Moody, J D; Zhang, D; Heinze, T M; Cerniglia, C E

    2000-08-01

    We examined Cunninghamella elegans to determine its ability to transform amoxapine, a tricyclic antidepressant belonging to the dibenzoxazepine class of drugs. Approximately 57% of the exogenous amoxapine was metabolized to three metabolites that were isolated by high-performance liquid chromatography and were identified by nuclear magnetic resonance and mass spectrometry as 7-hydroxyamoxapine (48%), N-formyl-7-hydroxyamoxapine (31%), and N-formylamoxapine (21%). 7-Hydroxyamoxapine, a mammalian metabolite with biological activity, now can be produced in milligram quantities for toxicological evaluation.

  4. Hydroxylation of 10-deoxoartemisinin by Cunninghamella elegans.

    Science.gov (United States)

    Parshikov, Igor A; Muraleedharan, Kannoth M; Miriyala, Bruhaspathy; Avery, Mitchell A; Williamson, John S

    2004-09-01

    The microbial metabolism of 10-deoxoartemisinin (1), a derivative of the antimalarial drug artemisinin, was investigated. Various strains of fungi were investigated for their ability to transform 1. Of these microorganisms, only Cunninghamella elegans was capable of transforming 1 to 5beta-hydroxy-10-deoxoartemisinin (2), 4alpha-hydroxy-1,10-deoxoartemisinin (3), and 7beta-hydroxy-10-deoxoartemisinin (4). The metabolites 2 and 4 retained an intact peroxide group and are therefore useful scaffolds for synthetic modification in the search for new antimalarial agents.

  5. Longevity and stress in Caenorhabditis elegans

    Science.gov (United States)

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

    2011-01-01

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

  6. TGF-β signaling in C. elegans.

    Science.gov (United States)

    Gumienny, Tina L; Savage-Dunn, Cathy

    2013-07-10

    Transforming Growth Factor-β (TGF-β) superfamily ligands regulate many aspects of cell identity, function, and survival in multicellular animals. Genes encoding five TGF-β family members are present in the genome of C. elegans. Two of the ligands, DBL-1 and DAF-7, signal through a canonical receptor-Smad signaling pathway; while a third ligand, UNC-129, interacts with a noncanonical signaling pathway. No function has yet been associated with the remaining two ligands. Here we summarize these signaling pathways and their biological functions.

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

    Science.gov (United States)

    Morcos, Michael; Hutter, Harald

    2009-01-01

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

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

    Science.gov (United States)

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

    2008-12-09

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

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

    Directory of Open Access Journals (Sweden)

    Emily R Troemel

    2008-12-01

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

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

    Science.gov (United States)

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

    2017-10-25

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

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

    Science.gov (United States)

    Powell, Jennifer R; Ausubel, Frederick M

    2008-01-01

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

  12. Biotransformation of fluorene by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Pothuluri, J V; Freeman, J P; Evans, F E; Cerniglia, C E

    1993-01-01

    The metabolism of fluorene, a tricyclic aromatic hydrocarbon, by Cunninghamella elegans ATCC 36112 was investigated. Approximately 69% of the [9-14C]fluorene added to cultures was metabolized within 120 h. The major ethyl acetate-soluble metabolites were 9-fluorenone (62%), 9-fluorenol, and 2-hydroxy-9-fluorenone (together, 7.0%). Similarly to bacteria, C. elegans oxidized fluorene at the C-9 position of the five-member ring to form an alcohol and the corresponding ketone. In addition, C. elegans produced the novel metabolite 2-hydroxy-9-fluorenone. PMID:8328814

  13. 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

  14. 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.

  15. Approaches for Studying Autophagy in Caenorhabditis elegans

    Science.gov (United States)

    Chen, Yanfang; Scarcelli, Vincent; Legouis, Renaud

    2017-01-01

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

  16. 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.

  17. Precision Electrophile Tagging in Caenorhabditis elegans.

    Science.gov (United States)

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

    2018-01-16

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

  18. Biotransformation of doxepin by Cunninghamella elegans.

    Science.gov (United States)

    Moody, J D; Freeman, J P; Cerniglia, C E

    1999-10-01

    A filamentous fungus, Cunninghamella elegans ATCC 9245, was used as a microbial model of mammalian metabolism to biotransform doxepin, a tricyclic antidepressant drug. Doxepin is produced as an 85:15% mixture of the trans- (E) and cis- (Z) forms. After 96 h of incubation in Sabouraud dextrose broth, 28% of the drug was metabolized to 16 metabolites. No change in the trans- (E) and cis- (Z) ratio of doxepin was observed. Metabolites were isolated by reversed phase HPLC and identified by (1)H NMR and mass spectroscopic analysis. The major metabolites were (E)-2-hydroxydoxepin, (E)-3-hydroxydoxepin, (Z)-8-hydroxydoxepin, (E)-2-hydroxy-N-desmethyldoxepin, (E)-3-hydroxy-N-desmethyldoxepin, (E)-4-hydroxy-N-desmethyldoxepin, (Z)- and (E)-8-hydroxy-N-desmethyldoxepin, (E)-N-acetyl-N-desmethyldoxepin, (E)-N-desmethyl-N-formyldoxepin, (E)-N-acetyldidesmethyldoxepin, (E)-and (Z)-doxepin-N-oxide, and (E)- and (Z)-N-desmethyldoxepin. Six of the metabolites produced by C. elegans were essentially similar to those obtained in human metabolism studies, although nine novel metabolites were identified.

  19. Monitoring Autophagic Responses in Caenorhabditis elegans.

    Science.gov (United States)

    Papandreou, M E; Tavernarakis, N

    2017-01-01

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

  20. The RNAi Inheritance Machinery of Caenorhabditis elegans.

    Science.gov (United States)

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

    2017-07-01

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

  1. 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.

  2. Caenorhabditis elegans reveals novel Pseudomonas aeruginosa virulence mechanism

    NARCIS (Netherlands)

    Utari, Putri Dwi; Quax, Wim J.

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

  3. 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...

  4. Pseudomonas aeruginosa PA14 pathogenesis in Caenorhabditis elegans.

    Science.gov (United States)

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

    2014-01-01

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

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

    Indian Academy of Sciences (India)

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

  6. 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...

  7. Microfluidics as a tool for C. elegans research.

    Science.gov (United States)

    San-Miguel, Adriana; Lu, Hang

    2013-01-01

    Microfluidics has emerged as a set of powerful tools that have greatly advanced some areas of biological research, including research using C. elegans. The use of microfluidics has enabled many experiments that are otherwise impossible with conventional methods. Today there are many examples that demonstrate the main advantages of using microfluidics for C. elegans research, achieving precise environmental conditions and facilitating worm handling. Examples range from behavioral analysis under precise chemical or odor stimulation, locomotion studies in well-defined structural surroundings, and even long-term culture on chip. Moreover, microfluidics has enabled coupling worm handling and imaging thus facilitating genetic screens, optogenetic studies, and laser ablation experiments. In this article, we review some of the applications of microfluidics for C. elegans research and provide guides for the design, fabrication, and use of microfluidic devices for C. elegans research studies. PMID:24065448

  8. 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...

  9. Tissue uptake, distribution and excretion of brevetoxin-3 after oral and intratracheal exposure in the freshwater turtle Trachemys scripta and the diamondback terrapin Malaclemys terrapin.

    Science.gov (United States)

    Cocilova, Courtney C; Flewelling, Leanne J; Bossart, Gregory D; Granholm, April A; Milton, Sarah L

    2017-06-01

    Harmful algal blooms (HABs) occur nearly annually off the west coast of Florida and can impact both humans and wildlife, resulting in morbidity and increased mortality of marine animals including sea turtles. The key organism in Florida red tides is the dinoflagellate Karenia brevis that produces a suite of potent neurotoxins referred to as the brevetoxins (PbTx). Despite recent mortality events and rehabilitation efforts, still little is known about how the toxin directly impacts sea turtles, as they are not amenable to experimentation and what is known about toxin levels and distribution comes primarily from post-mortem data. In this study, we utilized the freshwater turtle Trachemys scripta and the diamondback terrapin, Malaclemys terrapin as model organisms to determine the distribution, clearance, and routes of excretion of the most common form of the toxin, brevetoxin-3, in turtles. Turtles were administered toxin via esophageal tube to mimic ingestion (33.48μg/kg PbTx-3, 3×/week for two weeks for a total of 7 doses) or by intratracheal instillation (10.53μg/kg, 3×/week for four weeks for a total of 12 doses) to mimic inhalation. Both oral and intratracheal administration of the toxin produced a suite of behavioral responses symptomatic of brevetoxicosis. The toxin distributed to all organ systems within 1h of administration but was rapidly cleared out over 24-48h, corresponding to a decline in clinical symptoms. Excretion appears to be primarily through conjugation to bile salts. Histopathological study revealed that the frequency of lesions varied within experimental groups with some turtles having no significant lesions at all, while similar lesions were found in a low number of control turtles suggesting another common factor(s) could be responsible. The overall goal of this research is better understand the impacts of brevetoxin on turtles in order to develop better treatment protocols for sea turtles exposed to HABs. Copyright © 2017 Elsevier B

  10. In Vivo Inhibition of Lipid Accumulation in Caenorhabditis elegans

    Science.gov (United States)

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

    2017-03-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  14. 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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    The adherent invasive E. coli isolated from patients with Crohn’s disease in humans is pathogenic for C. elegans. We show here that when C. elegans feeds on the pathogenic E. coli, the life span is shortened significantly compared to the normal laboratory food, the OP50 E. coli. In this study the...... 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.  ...... 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......, many of which also have been found in studies using other pathogens. So far, large-scale investigations of the C. elegans immune response have been performed using micro-arrays. This study is the first to make use of quantitative proteomics to directly follow the protein dynamics during the infection...

  16. Mainstreaming Caenorhabditis elegans in experimental evolution.

    Science.gov (United States)

    Gray, Jeremy C; Cutter, Asher D

    2014-03-07

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

  17. 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.

  18. Transformation of artemisinin by Cunninghamella elegans.

    Science.gov (United States)

    Parshikov, I A; Muraleedharan, K M; Avery, M A; Williamson, J S

    2004-06-01

    Semi-synthetic derivatives of the anti-malarial drug artemisinin hold great promise in the search for an effective and economical treatment of chloroquine-resistant forms of malaria. Unfortunately, synthetic functionalization of the artemisinin skeleton is often tedious and/or impractical. We seek to utilize 7beta-hydroxyartemisinin, obtained from microbial transformation, as a semi-synthetic precursor for the synthesis of novel 7beta-substituted artemisinin anti-malarial agents. Here we employ liquid cultures of Cunninghamella elegans as a means for the rational and economical bioconversion of artemisinin to 7beta-hydroxyartemisinin in 78.6% yield. In addition, there were three other bioconversion products: 7beta-hydroxy-9alpha-artemisinin (6.0%), 4alpha-hydroxy-1-deoxoartemisinin (5.4%), and 6beta-hydroxyartemisinin (6.5%).

  19. Mainstreaming Caenorhabditis elegans in experimental evolution

    Science.gov (United States)

    Gray, Jeremy C.; Cutter, Asher D.

    2014-01-01

    Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host–pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery. PMID:24430852

  20. Big Data in Caenorhabditis elegans: quo vadis?

    Science.gov (United States)

    Hutter, Harald; Moerman, Donald

    2015-11-05

    A clear definition of what constitutes "Big Data" is difficult to identify, but we find it most useful to define Big Data as a data collection that is complete. By this criterion, researchers on Caenorhabditis elegans have a long history of collecting Big Data, since the organism was selected with the idea of obtaining a complete biological description and understanding of development. The complete wiring diagram of the nervous system, the complete cell lineage, and the complete genome sequence provide a framework to phrase and test hypotheses. Given this history, it might be surprising that the number of "complete" data sets for this organism is actually rather small--not because of lack of effort, but because most types of biological experiments are not currently amenable to complete large-scale data collection. Many are also not inherently limited, so that it becomes difficult to even define completeness. At present, we only have partial data on mutated genes and their phenotypes, gene expression, and protein-protein interaction--important data for many biological questions. Big Data can point toward unexpected correlations, and these unexpected correlations can lead to novel investigations; however, Big Data cannot establish causation. As a result, there is much excitement about Big Data, but there is also a discussion on just what Big Data contributes to solving a biological problem. Because of its relative simplicity, C. elegans is an ideal test bed to explore this issue and at the same time determine what is necessary to build a multicellular organism from a single cell. © 2015 Hutter and Moerman. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

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

    Science.gov (United States)

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

  2. Fast estimation of motion from selected populations of retinal ganglion cells.

    Science.gov (United States)

    Cerquera, Alexander; Freund, Jan

    2011-02-01

    We explore how the reconstruction efficiency of fast spike population codes varies with population size, population composition and code complexity. Our study is based on experiments with moving light patterns which are projected onto the isolated retina of a turtle Pseudemys scripta elegans. The stimulus features to reconstruct are sequences of velocities kept constant throughout segments of 500 ms. The reconstruction is based on the spikes of a retinal ganglion cell (RGC) population recorded extracellularly via a multielectrode array. Subsequent spike sorting yields the parallel spike trains of 107 RGCs as input to the reconstruction method, here a discriminant analysis trained and tested in jack-knife fashion. Motivated by behavioral response times, we concentrate on fast reconstruction, i.e., within 150 ms following a trigger event defined via significant changes of the population spike rate. Therefore, valid codes involve only few (≤3) spikes per cell. Using only the latency t(1) of each cell (with reference to the trigger event) corresponds to the most parsimonious population code considered. We evaluate the gain in reconstruction efficiency when supplementing t(1) by spike times t(2) and t(3). Furthermore, we investigate whether sub-populations of smaller size benefit significantly from a selection process or whether random compilations are equally efficient. As selection criteria we try different concepts (directionality, reliability, and discriminability). Finally, we discuss the implications of a selection process and its inter-relation with code complexity for optimized reconstruction.

  3. Removal of nonnative slider turtles (Trachemys scripta) and effects on native Sonora mud turtles (Kinosternon sonoriense) at Montezuma Well, Yavapai County, Arizona

    Science.gov (United States)

    Drost, Charles A.; Lovich, Jeffrey E.; Madrak, Sheila V.; Monatesti, A.J.

    2011-01-01

    The National Park Service (NPS) estimates that 234 national parks contain nonnative, invasive animal species that are of management concern (National Park Service, 2004). Understanding and controlling invasive species is thus an important priority within the NPS (National Park Service, 1996). The slider turtle (Trachemys scripta) is one such invasive species. Native to the Southeastern United States (Ernst and Lovich, 2009), as well as Mexico, Central America, and portions of South America (Ernst and Barbour, 1989), the slider turtle has become established throughout the continental United States and in other locations around the world (Burke and others, 2000). Slider turtle introductions have been suspected to be a threat to native turtles (Holland 1994; da Silva and Blasco, 1995), however, there has not been serious study of their effects until recently. Cadi and Joly (2003) found that slider turtles outcompeted European pond turtles (Emys orbicularis) for preferred basking sites under controlled experimental conditions, demonstrating for the first time direct competition for resources between a native and an exotic turtle species. Similarly, Spinks and others (2003) suggested that competition for basking sites between slider turtles and Pacific pond turtles (Actinemys marmorata) was partly responsible for the decline of Pacific pond turtles observed at their study site in California. They concluded that the impact of introduced slider turtles was 'almost certainly negative' for the western pond turtle. In the most recent critical study to assess the effects of introduced slider turtles on native turtles, Cadi and Joly (2004) demonstrated that European pond turtles that were kept under experimentally controlled conditions with slider turtles lost body weight and exhibited higher rates of mortality than in control groups of turtles comprised of the same species, demonstrating potential population-level effects on native species. Slider turtles are not native to

  4. Worms on the spectrum - C. elegans models in autism research.

    Science.gov (United States)

    Schmeisser, Kathrin; Parker, J Alex

    2017-04-20

    The small non-parasitic nematode Caenorhabditis elegans is widely used in neuroscience thanks to its well-understood development and lineage of the nervous system. Furthermore, C. elegans has been used to model many human developmental and neurological conditions to better understand disease mechanisms and identify potential therapeutic strategies. Autism spectrum disorder (ASD) is the most prevalent of all neurodevelopmental disorders, and the C. elegans system may provide opportunities to learn more about this complex disorder. Since basic cell biology and biochemistry of the C. elegans nervous system is generally very similar to mammals, cellular or molecular phenotypes can be investigated, along with a repertoire of behaviours. For instance, worms have contributed greatly to the understanding of mechanisms underlying mutations in genes coding for synaptic proteins such as neuroligin and neurexin. Using worms to model neurodevelopmental disorders like ASD is an emerging topic that harbours great, untapped potential. This review summarizes the numerous contributions of C. elegans to the field of neurodevelopment and introduces the nematode system as a potential research tool to study essential roles of genes associated with ASD. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Fungal metabolism of acenaphthene by Cunninghamella elegans.

    Science.gov (United States)

    Pothuluri, J V; Freeman, J P; Evans, F E; Cerniglia, C E

    1992-01-01

    The filamentous fungus Cunninghamella elegans ATCC 36112 metabolized within 72 h of incubation approximately 64% of the [1,8-14C]acenaphthene added. The radioactive metabolites were extracted with ethyl acetate and separated by thin-layer chromatography and reversed-phase high-performance liquid chromatography. Seven metabolites were identified by 1H nuclear magnetic resonance, UV, and mass spectral techniques as 6-hydroxyacenaphthenone (24.8%), 1,2-acenaphthenedione (19.9%), trans-1,2-dihydroxyacenaphthene (10.3%), 1,5-dihydroxyacenaphthene (2.7%), 1-acenaphthenol (2.4%), 1-acenaphthenone (2.1%), and cis-1,2-dihydroxyacenaphthene (1.8%). Parallel experiments with rat liver microsomes indicated that the major metabolite formed from acenaphthene by rat liver microsomes was 1-acenaphthenone. The fungal metabolism of acenaphthene was similar to bacterial and mammalian metabolism, since the primary site of enzymatic attack was on the two carbons of the five-member ring. PMID:1482186

  10. 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.

  11. 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. Copyright © 2016 John Wiley & Sons, Inc.

  12. 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.

  13. Complete mitochondrial genome of Eumeces elegans (Squamata: Scincidae).

    Science.gov (United States)

    Song, Tao; Zhang, Chenling; Huang, Xin; Zhang, Baowei

    2016-01-01

    Eumeces elegans is a kind of blue-tailed lizard in the genus Eumeces, and widely distributed in southern provinces of China. We sequenced and characterized the complete mitochondrial genome of Eumeces elegans. The total length of the complete mitochondrial genome was 17,304 bp with 13 protein-coding genes, 22 tRNAs, two rRNAs and a control regions. The overall base composition of Eumeces elegans was 31.0% A, 15.0% G, 29.8% C, and 24.2% T. ND6 subunit gene and eight tRNA genes were encoded on the L-stand, and other genes were distributed on the H-strand.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Y.-L. Zhao

    2012-01-01

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

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

    Science.gov (United States)

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

    2017-08-20

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

  17. 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.

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

    Science.gov (United States)

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

    2018-02-02

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

  19. 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.

  20. 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.

  1. 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.

  2. 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…

  3. Elytron length and sexual dimorphism in Zonocerus elegans (Thunb ...

    African Journals Online (AJOL)

    Adults of the African pyrgomorphid grasshopper, Zonocerus elegans Thunberg, exhibit strong alar polymorphism, especially in the male sex, with wings either vestigial or fully developed. Analysis of body and elytron lengths of about 400 insects revealed sexual dimorphism, females being larger than males, and showed a ...

  4. 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...

  5. 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

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

    Science.gov (United States)

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

    2013-01-01

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

  7. Osmotic potential of Zinnia elegans plant material affects the yield ...

    African Journals Online (AJOL)

    Jane

    2010-12-20

    Dec 20, 2010 ... eso ph yll cell lenght (µ m. ) Figure 3. Effect of different light intensities on the leaf mesophyll size (A, length; B, area) and LO (C) in two cvs of Z. elegans seedlings at Ht. Different letters indicate statistically significant differences. Bar = SEM, N = 8 for LO measurements;. N = 30 for mesophyll cell size ...

  8. 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.

  9. Phomalactone from a phytopathogenic fungus infecting Zinnia elegans (Asteraceae) leaves

    Science.gov (United States)

    Zinnia elegans plants are infected by a fungus that causes necrosis with dark red spots particularly in late spring to the middle of summer in the Mid-South part of the United States. This fungal disease when untreated causes the leaves to wilt and eventually kills the plant. The fungus was isolated...

  10. 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

  11. Antagonistic sensory cues generate gustatory plasticity in Caenorhabditis elegans

    NARCIS (Netherlands)

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

    2006-01-01

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

  12. Metabolism of an Insecticide Fenitrothion by Cunninghamella elegans ATCC36112.

    Science.gov (United States)

    Zhu, Yong-Zhe; Fu, Min; Jeong, In-Hong; Kim, Jeong-Han; Zhang, Chuan-Jie

    2017-11-16

    In this study, the detailed metabolic pathways of fenitrothion (FNT), an organophosphorus insecticide by Cunninghamella elegans was investigated. Approximately 81% of FNT was degraded within 5 d after treatment with concomitant accumulation of four metabolites (M1-M4). The four metabolites were separated by HPLC and their structures were identified by MS and/or NMR. M3 is confirmed to be an initial precursor of others and identified as fenitrothion-oxon (FNTO). On the basis of their metabolic profiling, the possible metabolic pathways involved in phase I and II metabolism of FNT by C. elegans was proposed. We also found C. elegans was able to efficiently and rapidly degrade other organophosphorus pesticides (OPs). Thus, these results will provide an insight into understanding of the fungal degradation of FNT and the potential application for bioremediation of OPs. Furthermore, the ability of C. elegans to mimic mammalian metabolism would help us elucidate the metabolic fates of organic compounds occurring in mammalian liver cells and evaluate their toxicity and potential adverse effects.

  13. Microbial transformation of 6-nitrobenzo(a)pyrene. [Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    Millner, G.C.; Fu, P.P.; Cerniglia, C.E.

    1986-01-01

    The fungal metabolism of the potent mutagenic and carcinogenic nitropolycyclic aromatic hydrocarbon (nitro-PAH) 6-nitrobenzo(a)pyrene (6-NO/sub 2/-BaP) was investigated. Cunninghamella elegans was incubated with 6-NO/sub 2/-BaP for periods ranging between 1 and 7 d, and the metabolites formed were separated by high-performance liquid chromatography and identified by their UV-visible absorption, mass, and /sup 1/H nuclear magnetic resonance spectra. The results of the study indicate that C. elegans metabolized 6-NO/sub 2/-BaP to glucoside and sulfate conjugates of 1- and 3-hydroxy 6-NO/sub 2/-BaP and suggests that glycosylation and sulfation reactions may represent detoxification pathways in the fungal metabolism of nitro-PAHs. Experiments using (G-/sup 3/H)-6-NO/sub 2/-BaP indicated that C. elegans metabolized 62% of 6-NO/sub 2/-BaP with 168 h. The data also indicated that the nitro group at the C-6 position of benzo(a)pyrene blocked metabolism at the regions peri to the nitro substituent (C-7, C-8 positions) and enhanced metabolism at the C-1 and C-3 positions. The ability of the fungus C. elegans to metabolize 6-NO/sub 2/-BaP to biologically inactive compounds may have practical applications in the detoxification of nitro-PAH-contaminated wastes.

  14. 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

  15. 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...

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

    Directory of Open Access Journals (Sweden)

    Brent Cezairliyan

    2013-01-01

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

  17. Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

    Science.gov (United States)

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

    2013-01-01

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

  18. 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.

  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. A description of the life stages of Echinoparyphium elegans ...

    African Journals Online (AJOL)

    The life cycle of Echinoparyphium elegans Looss 1899 is described from the Free State, South Africa.The freshwater snail Bulinus tropicus (Krauss 1848), the intermediate host of Calicophorort microbothrium (Paramphistomum microbothrium Fischoeder, 1901) in this area, serves as first intermediate host. The same snail ...

  1. Sorbus alnifolia protects dopaminergic neurodegeneration in Caenorhabditis elegans.

    Science.gov (United States)

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

    2017-12-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. An atlas of Caenorhabditis elegans chemoreceptor expression

    Science.gov (United States)

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

    2018-01-01

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

  5. Axon regeneration in C. elegans: Worming our way to mechanisms of axon regeneration.

    Science.gov (United States)

    Byrne, Alexandra B; Hammarlund, Marc

    2017-01-01

    How axons repair themselves after injury is a fundamental question in neurobiology. With its conserved genome, relatively simple nervous system, and transparent body, C. elegans has recently emerged as a productive model to uncover the cellular mechanisms that regulate and execute axon regeneration. In this review, we discuss the strengths and weaknesses of the C. elegans model of regeneration. We explore the technical advances that enable the use of C. elegans for in vivo regeneration studies, review findings in C. elegans that have contributed to our understanding of the regeneration response across species, discuss the potential of C. elegans research to provide insight into mechanisms that function in the injured mammalian nervous system, and present potential future directions of axon regeneration research using C. elegans. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced ......-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms....

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

    OpenAIRE

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

    2013-01-01

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

  8. 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

  9. Regulatory elements of Caenorhabditis elegans ribosomal protein genes

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    Palm Megan

    2005-01-01

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

  11. C. elegans flavin-containing monooxygenase-4 is essential for osmoregulation in hypotonic stress

    National Research Council Canada - National Science Library

    Hirani, Nisha; Westenberg, Marcel; Seed, Paul T; Petalcorin, Mark I R; Dolphin, Colin T

    2016-01-01

    Studies in Caenorhabditis elegans have revealed osmoregulatory systems engaged when worms experience hypertonic conditions, but less is known about measures employed when faced with hypotonic stress...

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

    Directory of Open Access Journals (Sweden)

    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.

  13. The C. elegans neural editome reveals an ADAR target mRNA required for proper chemotaxis

    National Research Council Canada - National Science Library

    Deffit Sarah N; Yee Brian A; Manning Aidan C; Rajendren Suba; Vadlamani Pranathi; Wheeler Emily C; Domissy Alain; Washburn Michael C; Yeo Gene W; Hundley Heather A

    2017-01-01

    .... Loss of ADARs affects neuronal function in all animals studied to date. Caenorhabditis elegans lacking ADARs exhibit reduced chemotaxis, but the targets responsible for this phenotype remain unknown...

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

    Directory of Open Access Journals (Sweden)

    Sakiko Honjoh

    2017-12-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

  16. 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...

  17. Noncanonical cell death in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Kinet, Maxime J; Shaham, Shai

    2014-01-01

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

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

    Science.gov (United States)

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

    2005-11-10

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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

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

    OpenAIRE

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

    2015-01-01

    Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons....

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

    Directory of Open Access Journals (Sweden)

    Guillermina Hernando

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

  5. Metabolism of quercetin by Cunninghamella elegans ATCC 9245.

    Science.gov (United States)

    Zi, Jiachen; Valiente, Jonathan; Zeng, Jia; Zhan, Jixun

    2011-10-01

    Incubation of quercetin with Cunninghamella elegans ATCC 9245 yielded three metabolites, including quercetin 3-O-β-D-glucopyranoside, kaempferol 3-O-β-D-glucopyranoside and isorhamnetin 3-O-β-D-glucopyranoside. Glucosylation, O-methylation and dehydroxylation were involved in the process, among which dehydroxylation has never been found in Cunninghamella. Quercetin was completely metabolized in 72 h. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  6. Fungal biotransformation of the antihistamine azatadine by Cunninghamella elegans.

    Science.gov (United States)

    Zhang, D; Hansen, E B; Deck, J; Heinze, T M; Sutherland, J B; Cerniglia, C E

    1996-01-01

    The metabolism of the antihistamine azatadine by the zygomycete fungus Cunninghamella elegans ATCC 9245 was investigated. Within 72 h from the addition of the drug to 48-h-old cultures grown in Sabouraud dextrose broth, 95% of azatadine was biotransformed. Two major metabolites, 7-hydroxyazatadine (25%) and 8-hydroxyazatadine (50%), and two minor metabolites, N-desmethylazatadine and 9-hydroxyazatadine, were isolated by high-performance liquid chromatography and characterized by mass spectrometric and proton nuclear magnetic resonance spectroscopic analyses. PMID:8795241

  7. Fungal biotransformation of the antihistamine azatadine by Cunninghamella elegans.

    OpenAIRE

    Zhang, D.; Hansen, E B; Deck, J; Heinze, T M; Sutherland, J B; Cerniglia, C E

    1996-01-01

    The metabolism of the antihistamine azatadine by the zygomycete fungus Cunninghamella elegans ATCC 9245 was investigated. Within 72 h from the addition of the drug to 48-h-old cultures grown in Sabouraud dextrose broth, 95% of azatadine was biotransformed. Two major metabolites, 7-hydroxyazatadine (25%) and 8-hydroxyazatadine (50%), and two minor metabolites, N-desmethylazatadine and 9-hydroxyazatadine, were isolated by high-performance liquid chromatography and characterized by mass spectrom...

  8. Biotransformation of adrenosterone by filamentous fungus, Cunninghamella elegans.

    Science.gov (United States)

    Choudhary, Muhammad Iqbal; Khan, Naik T; Musharraf, Syed G; Anjum, Shazia; Atta-Ur-Rahman

    2007-12-01

    Microbial transformation of adrenosterone (1) by suspended-cell cultures of the filamentous fungus Cunninghamella elegans resulted in the production of five metabolites 2-6, which were identified as 9alpha-hydroxyadrenosterone (2), 11-ketotestosterone (3), 6beta-hydroxyadrenosterone (4), 9alpha-hydroxy-11-ketotestosterone (5), and 6beta-hydroxy-11-ketotestosterone (6). Structures of new metabolites 2, 5, and 6 were established by single-crystal X-ray diffraction analysis.

  9. Biotransformation of malachite green by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Cha, C J; Doerge, D R; Cerniglia, C E

    2001-09-01

    The filamentous fungus Cunninghamella elegans ATCC 36112 metabolized the triphenylmethane dye malachite green with a first-order rate constant of 0.029 micromol x h(-1) (mg of cells)(-1). Malachite green was enzymatically reduced to leucomalachite green and also converted to N-demethylated and N-oxidized metabolites, including primary and secondary arylamines. Inhibition studies suggested that the cytochrome P450 system mediated both the reduction and the N-demethylation reactions.

  10. Biotransformation of Malachite Green by the Fungus Cunninghamella elegans

    OpenAIRE

    Cha, Chang-Jun; Doerge, Daniel R.; Cerniglia, Carl E.

    2001-01-01

    The filamentous fungus Cunninghamella elegans ATCC 36112 metabolized the triphenylmethane dye malachite green with a first-order rate constant of 0.029 μmol h−1 (mg of cells)−1. Malachite green was enzymatically reduced to leucomalachite green and also converted to N-demethylated and N-oxidized metabolites, including primary and secondary arylamines. Inhibition studies suggested that the cytochrome P450 system mediated both the reduction and the N-demethylation reactions.

  11. Effects of phosphorus on polyphosphate accumulation by Cunninghamella elegans

    OpenAIRE

    Marcos Antonio Barbosa de Lima; Aline Elesbão do Nascimento; Wanderley de Souza; Kazutaka Fukushima; Galba Maria Campos-Takaki

    2003-01-01

    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 b...

  12. Biotransformation of chrysin and apigenin by Cunninghamella elegans.

    Science.gov (United States)

    Ibrahim, Abdel-Rahim Sayed

    2005-06-01

    Biotransformation of chrysin by Cunninghamella elegans NRRL 1392 produced apigenin, apigenin 7-sulfate, apigenin 7,4'-disulfate, and a new metabolite identified as chrysin 7-sulfate. On the other hand, fermentation of apigenin, using the same microorganism, yielded apigenin 7-sulfate and apigenin 7,4'-disulfate. The structures of the metabolites were established by spectral analysis, and acid and enzyme hydrolyses in addition to comparison with reference samples.

  13. Biotransformation of fluorene by the fungus Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    Yinxia Li

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

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

    Science.gov (United States)

    Reinke, Valerie; Cutter, Asher D

    2009-04-01

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

  16. A global analysis of C. elegans trans-splicing

    Science.gov (United States)

    Allen, Mary Ann; Hillier, LaDeana W.; Waterston, Robert H.; Blumenthal, Thomas

    2011-01-01

    Trans-splicing of one of two short leader RNAs, SL1 or SL2, occurs at the 5′ ends of pre-mRNAs of many C. elegans genes. We have exploited RNA-sequencing data from the modENCODE project to analyze the transcriptome of C. elegans for patterns of trans-splicing. Transcripts of ∼70% of genes are trans-spliced, similar to earlier estimates based on analysis of far fewer genes. The mRNAs of most trans-spliced genes are spliced to either SL1 or SL2, but most genes are not trans-spliced to both, indicating that SL1 and SL2 trans-splicing use different underlying mechanisms. SL2 trans-splicing occurs in order to separate the products of genes in operons genome wide. Shorter intercistronic distance is associated with greater use of SL2. Finally, increased use of SL1 trans-splicing to downstream operon genes can indicate the presence of an extra promoter in the intercistronic region, creating what has been termed a “hybrid” operon. Within hybrid operons the presence of the two promoters results in the use of the two SL classes: Transcription that originates at the promoter upstream of another gene creates a polycistronic pre-mRNA that receives SL2, whereas transcription that originates at the internal promoter creates transcripts that receive SL1. Overall, our data demonstrate that >17% of all C. elegans genes are in operons. PMID:21177958

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

    Science.gov (United States)

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

    2007-10-01

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

  18. DNA Methylation and Potential for Epigenetic Regulation in Pygospio elegans

    Science.gov (United States)

    Kesäniemi, Jenni E.; Heikkinen, Liisa; Knott, K. Emily

    2016-01-01

    Transitions in developmental mode are common evolutionarily, but how and why they occur is not understood. Developmental mode describes larval phenotypes, including morphology, ecology and behavior of larvae, which typically are generalized across different species. The polychaete worm Pygospio elegans is one of few species polymorphic in developmental mode, with multiple larval phenotypes, providing a possibility to examine the potential mechanisms allowing transitions in developmental mode. We investigated the presence of DNA methylation in P. elegans, and, since maternal provisioning is a key factor determining eventual larval phenotype, we compared patterns of DNA methylation in females during oogenesis in this species. We demonstrate that intragenic CpG site DNA methylation and many relevant genes necessary for DNA methylation occur in P. elegans. Methylation-sensitive AFLP analysis showed that gravid females with offspring differing in larval developmental mode have significantly different methylation profiles and that the females with benthic larvae and non-reproductive females from the same location also differ in their epigenetic profiles. Analysis of CpG sites in transcriptome data supported our findings of DNA methylation in this species and showed that CpG observed/expected ratios differ among females gravid with embryos destined to different developmental modes. The differences in CpG site DNA methylation patterns seen among the samples suggest a potential for epigenetic regulation of gene expression (through DNA methylation) in this species. PMID:27008314

  19. Metabolism of metolachlor by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Pothuluri, J V; Evans, F E; Doerge, D R; Churchwell, M I; Cerniglia, C E

    1997-02-01

    The metabolism of metolachlor[2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-met hyl ethyl)acetamide]by the fungus Cunninghamella elegans ATCC 36112 was determined. Thesix metabolites identified comprised 81% of the total[14C]-metolachlor metabolized by C. elegans. Thesemetabolites were separated by reversed-phase high-performance liquidchromatography and identified by 1H nuclear magnetic resonance, UV, and atmospheric pressure chemical ionization (APCI) mass spectraltechniques. Metabolites I and II were identified as stereoismers of2-chloro-N-[2-ethyl-6-hydroxymethylphenyl)]-N-(2-hydroxy-1-me thylet hyl)acetamide. Metabolites III and IV have been tentatively identified as stereoismers of2-chloro-N-[2-(1-hydroxyethyl)-6-methylphenyl]-N-(2-methoxy-1-++ +methy lethyl)acetamide. Metabolites V and VI were identified as stereoismers of2-chloro-N-(2-ethyl-6-hydroxy-methylphenyl)-N-(2-methoxy-1-me thylet hyl)acetamideand 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-hydroxy-1-methylethyl)acetam ide, respectively. The fungus Cunninghamellaelegans was able to biotransform metolachlor. Multiple site oxidation ofmetolachlor by C. elegans occurred predominantly byO-demethylation of the N-alkyl side chain and benzylichydroxylation of the arylalkyl side chain.

  20. Biotransformation of chlorpromazine and methdilazine by Cunninghamella elegans.

    Science.gov (United States)

    Zhang, D; Freeman, J P; Sutherland, J B; Walker, A E; Yang, Y; Cerniglia, C E

    1996-01-01

    When tested as a microbial model for mammalian drug metabolism, the filamentous fungus Cunninghamella elegans metabolized chlorpromazine and methdilazine within 72 h. The metabolites were extracted by chloroform, separated by high-performance liquid chromatography, and characterized by proton nuclear magnetic resonance, mass, and UV spectroscopic analyses. The major metabolites of chlorpromazine were chlorpromazine sulfoxide (36%), N-desmethylchlorpromazine (11%), N-desmethyl-7-hydroxychlorpromazine (6%), 7-hydroxychlorpromazine sulfoxide (36%), N-hydroxychlorpromazine (11%), 7-hydroxychlorpromazine sulfoxide (5%), and chlorpromazine N-oxide (2%), all of which have been found in animal studies. The major metabolites of methdilazine were 3-hydroxymethdilazine (3%). (18)O(2) labeling experiments indicated that the oxygen atoms in methdilazine sulfoxide, methdilazine N-oxide, and 3-hydroxymethdilazine were all derived from molecular oxygen. The production of methdilazine sulfoxide and 3-hydroxymethdilazine was inhibited by the cytochrome P-450 inhibitors metyrapone and proadifen. An enzyme activity for the sulfoxidation of methdilazine was found in microsomal preparations of C. elegans. These experiments suggest that the sulfoxidation and hydroxylation of methdilazine and chlorpromazine by C. elegans are catalyzed by cytochrome P-450. PMID:8975609

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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.

  3. Tomosyn inhibits synaptic vesicle priming in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Elena O Gracheva

    2006-07-01

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

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

    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.

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

    Directory of Open Access Journals (Sweden)

    Jin-ling CAI

    2012-09-01

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

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

    Science.gov (United States)

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

    2013-12-17

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

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

    Science.gov (United States)

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

  8. A sensitive mass spectrometry platform identifies metabolic changes of life history traits in C-elegans

    NARCIS (Netherlands)

    Gao, Arwen W.; Chatzispyrou, Iliana A.; Kamble, Rashmi; Liu, Yasmine J.; Herzog, Katharina; Smith, Reuben L.; van Lenthe, Henk; Vervaart, Martin A. T.; van Cruchten, Arno; Luyf, Angela C.; van Kampen, Antoine; Pras-Raves, Mia L.; Vaz, Frédéric M.; Houtkooper, Riekelt H.

    2017-01-01

    Abnormal nutrient metabolism is a hallmark of aging, and the underlying genetic and nutritional framework is rapidly being uncovered, particularly using C. elegans as a model. However, the direct metabolic consequences of perturbations in life history of C. elegans remain to be clarified. Based on

  9. Blue native electrophoresis to study mitochondrial complex I in C. elegans.

    NARCIS (Netherlands)

    Ecker, D. van den; Brand, M.A.M. van den; Bossinger, O.; Mayatepek, E.; Nijtmans, L.G.J.; Distelmaier, F.

    2010-01-01

    Blue native polyacrylamide gel electrophoresis (BN-PAGE) is an essential tool for investigating mitochondrial respiratory chain complexes. However, with current BN-PAGE protocols for Caenorhabditis elegans (C. elegans), large worm amounts and high quantities of mitochondrial protein are required to

  10. 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 ...

  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

  12. 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,…

  13. 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.

  14. Regiospecific synthesis of isoapocodeine from 10,11-dimethoxyaporphine by using Cunninghamella elegans.

    Science.gov (United States)

    Smith, R V; Davis, P J

    1978-01-01

    A preparative-scale regiospecific conversion of 10,11-dimethoxyaporphine to isoapocodeine was conducted with Cunninghamella elegans ATCC 9245. This biotransformation proceeded quantitatively in suspensions and was pH dependent. The influence of antioxidants on the conversion was studied. Attempts to preserve the activity of isolated C. elegans cells by a number of methods were unsuccessful. PMID:25623

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-09-25

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

  17. 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...

  18. 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…

  19. 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...

  20. Signaling proteins that regulate NaCl [corrected] chemotaxis responses modulate longevity in C. elegans

    NARCIS (Netherlands)

    H. Lans (Hannes); M.P.J. Dekkers (Martijn); R.K. Hukema (Renate); N.J. Bialas (Nathan); M.R. Leroux (Michel); G. Jansen (Gert)

    2009-01-01

    textabstractThe lifespan of the nematode Caenorhabditis elegans is regulated by sensory signals detected by the amphid neurons. In these neurons, C. elegans expresses at least 14 Galpha subunits and a Ggamma subunit. We have identified seven sensory Galpha subunits that modulate lifespan. Genetic

  1. 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.

  2. 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…

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

    Science.gov (United States)

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    -induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show......Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety......-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms....

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

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    Schoofs Liliane

    2010-02-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  7. Cas9 Variants Expand the Target Repertoire in Caenorhabditis elegans

    Science.gov (United States)

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

    2016-01-01

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

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

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

    2017-06-01

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

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

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    Adam L Nekimken

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

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

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

    2017-09-13

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

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

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    Jeon, Hoon; Cha, Dong Seok

    2016-05-01

    The present study investigated the effects and underlying mechanism of ethylacetate fraction of Ribes fasciculatum (ERF) on the lifespan and stress tolerance using a Caenorhabditis elegans model. The longevity activity of ERF was determined by lifespan assay under normal culture condition. The survival rate of nematodes under various stress conditions was assessed to validate the effects of ERF on the stress tolerance. To determine the antioxidant potential of ERF, the superoxide dismutase (SOD) activities and intracellular reactive oxygen species (ROS) levels were investigated. The ERF-mediated change in SOD-3 expression was examined using GFP-expressing transgenic strain. The effects of ERF on the aging-related factors were investigated by reproduction assay and pharyngeal pumping assay. The intestinal lipofuscin levels of aged nematodes were also measured. The mechanistic studies were performed using selected mutant strains. Our results indicated that ERF showed potent lifespan extension effects on the wild-type nematode under both normal and various stress conditions. The ERF treatment also enhanced the activity and expression of superoxide dismutase (SOD) and attenuated the intracellular ROS levels. Moreover, ERF-fed nematodes showed decreased lipofuscin accumulation, indicating ERF might affect age-associated changes in C. elegans. The results of mechanistic studies indicated that there was no significant lifespan extension in ERF-treated daf-2, age-1, sir-2.1, and daf-16 null mutants, suggesting that they were involved in ERF-mediated lifespan regulation. In conclusion, R. fasciculatum confers increased longevity and stress resistance in C. elegans via SIR-2.1-mediated DAF-16 activation, dependent on the insulin/IGF signaling pathway. Copyright © 2016 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  12. Antimicrobial Susceptibilities of Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans.

    Science.gov (United States)

    Alberti, Michael O; Hindler, Janet A; Humphries, Romney M

    2015-12-14

    Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans. NVS are an important cause of bacteremia and infective endocarditis (IE) associated with significant morbidity and mortality. Antimicrobial susceptibility testing (AST) was performed for 14 antimicrobials using the broth microdilution MIC method described in the Clinical and Laboratory Standards Institute (CLSI) M45 guideline. A total of 132 clinical NVS blood isolates collected from 2008 to 2014 were tested. Species level identification of NVS isolates was achieved by 16S rRNA gene sequencing and/or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Ninety isolates were identified as G. adiacens, 37 as A. defectiva, and 5 as G. elegans. All isolates were susceptible to vancomycin (MIC90 = 1 μg/ml), and none displayed high-level resistance to aminoglycosides. G. adiacens was considerably more susceptible to penicillin than A. defectiva (38.9% versus 10.8% of isolates susceptible) but was less susceptible to cephalosporins than was A. defectiva (43.3% versus 100% of isolates susceptible to ceftriaxone). Several isolates were resistant to levofloxacin (6%), erythromycin (51%), and clindamycin (10%). The MIC90 for daptomycin was ≥ 4 μg/ml for G. adiacens and A. defectiva. G. elegans isolates were 100% susceptible to all antimicrobials tested, with the exception of erythromycin, to which only 20% were susceptible. This study provides antimicrobial susceptibility data for a recent collection of NVS and demonstrates important NVS species-related differences with respect to susceptibility to penicillin, cephalosporins, carbapenems, and daptomycin. Species-level identification of NVS organisms when susceptibility testing is not readily available may aid in treatment decisions. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

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

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    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.

  14. 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.

  15. A Caenorhabditis elegans Mass Spectrometric Resource for Neuropeptidomics

    Science.gov (United States)

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

    2018-01-01

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

  16. Structural properties of the Caenorhabditis elegans neuronal network.

    Directory of Open Access Journals (Sweden)

    Lav R Varshney

    2011-02-01

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

  17. Google matrix analysis of C.elegans neural network

    Science.gov (United States)

    Kandiah, V.; Shepelyansky, D. L.

    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.

  18. 5'-AMP-Activated Protein Kinase Signaling in Caenorhabditis elegans.

    Science.gov (United States)

    Ahmadi, Moloud; Roy, Richard

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

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

    Science.gov (United States)

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

    2014-09-01

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

  20. 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.

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

    Science.gov (United States)

    Pukkila-Worley, Read; Ausubel, Frederick M

    2012-02-01

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

  2. Oxidation of lynestrenol by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Iqbal Choudhary, M; Atif, M; Ur-Rahman, Atta

    2010-01-01

    Transformation of lynestrenol (19-nor-17alpha-pregn-4-en-20-yn-17beta-ol) (1) was carried out by incubation with Cunninghamella elegans to obtain 19-nor-17alpha-pregn-4-en-20-yn-3-one-10beta,17beta-diol (2), 19-nor-17alpha-pregn-4-en-20-yn-3-one-6beta,17beta-diol (3), and 19-nor-17alpha-pregn-4-en-20-yn-3beta,6beta,17beta-triol (4). Metabolite 4 was identified as a new compound. These metabolites were structurally characterised on the basis of spectroscopic techniques.

  3. Biotransformation of patchoulol by Cunninghamella echinulata var. elegans.

    Science.gov (United States)

    Xu, Fangfang; Liao, Kangsheng; Liu, Yuhong; Zhang, Zhenbiao; Guo, Dean; Su, Ziren; Liu, Bo

    2016-03-01

    Biocatalysis of patchoulol (PA) was performed by the fungus Cunninghamella echinulata var. elegans. Eight metabolites (1-8) including four new compounds were obtained, and their structures were elucidated as (5R,8S)-5,8 dihydroxypatchoulol (1), (5R*,9R*)-5,9 dihydroxypatchoulol (2), (6S*, 9S*)-6,9 dihydroxypatchoulol (3), and (4R*)-4 hydroxypatchoulol (4) by spectroscopic analysis. The absolute configuration of 1 was determined by single crystal X-ray diffraction. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    1994-02-01

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

  5. Biomass of freshwater turtles: a geographic comparison

    Energy Technology Data Exchange (ETDEWEB)

    Congdon, J.D.; Greene, J.L.; Gibbons, J.W.

    1986-01-01

    Standing crop biomass of freshwater turtles and minimum annual biomass of egg production were calculated for marsh and farm pond habitats in South Caroling and in Michigan. The species in South Carolina included Chelydra serpentina, Deirochelys reticularia, Kinosternon subrubrum, Pseudemys floridana, P. scripta and Sternotherus odoratus. The species in Michigan were Chelydra serpentina, Chrysemys picta and Emydoidea blandingi. Biomass was also determined for a single species population of P. scripta on a barrier island near Charleston, South Carolina. Population density and biomass of Pseudemys scripta in Green Pond on Capers Island were higher than densities and biomass of the entire six-species community studied on the mainland. In both the farm pond and marsh habitat in South Carolina P. scripta was the numerically dominant species and had the highest biomass. In Michigan, Chrysemys picta was the numerically dominant species; however, the biomass of Chelydra serpentina was higher. The three-species community in Michigan in two marshes (58 kg ha/sup -1/ and 46 kg ha/sup -1/) and farm ponds (23 kg ha/sup -1/) had lower biomasses than did the six-species community in a South Carolina marsh (73 kg/sup -1/). Minimum annual egg production by all species in South Carolina averaged 1.93 kg ha/sup -1/ and in Michigan averaged 2.89 kg ha/sup -1/ of marsh.

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

    Science.gov (United States)

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

    2016-01-01

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

  7. 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

  8. Isolation of specific neurons from C. elegans larvae for gene expression profiling.

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    W Clay Spencer

    Full Text Available The simple and well-described structure of the C. elegans nervous system offers an unprecedented opportunity to identify the genetic programs that define the connectivity and function of individual neurons and their circuits. A correspondingly precise gene expression map of C. elegans neurons would facilitate the application of genetic methods toward this goal. Here we describe a powerful new approach, SeqCeL (RNA-Seq of C. elegans cells for producing gene expression profiles of specific larval C. elegans neurons.We have exploited available GFP reporter lines for FACS isolation of specific larval C. elegans neurons for RNA-Seq analysis. Our analysis showed that diverse classes of neurons are accessible to this approach. To demonstrate the applicability of this strategy to rare neuron types, we generated RNA-Seq profiles of the NSM serotonergic neurons that occur as a single bilateral pair of cells in the C. elegans pharynx. These data detected >1,000 NSM enriched transcripts, including the majority of previously known NSM-expressed genes.This work offers a simple and robust protocol for expression profiling studies of post-embryonic C. elegans neurons and thus provides an important new method for identifying candidate genes for key roles in neuron-specific development and function.

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

    Science.gov (United States)

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

    2017-09-22

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

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

    Science.gov (United States)

    2012-01-01

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

  11. 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

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

    Science.gov (United States)

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

    2010-01-01

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

  13. Evolution of host innate defence: insights from C. elegans and primitive invertebrates

    Science.gov (United States)

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

    2010-01-01

    Preface The genetically tractable model organism Caenorhabditis elegans was first used to model bacterial virulence in vivo a decade ago. Since then, great strides have been made in the identification of host response pathways that are involved in the defence against infection. Strikingly, C. elegans seems to detect and respond to infection without the involvement of its Toll-like receptor homologue, in contrast to the well-established role for these proteins in innate immunity in mammals. What, therefore, do we know about host defence mechanisms in C. elegans, and what can they tell us about innate immunity in higher organisms? PMID:20029447

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

    Science.gov (United States)

    Hulme, S Elizabeth; Whitesides, George M

    2011-05-16

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

  15. 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.

    . 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...

  16. 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.

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Naama Feldman

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

  19. Spatiotemporal regulation of autophagy during Caenorhabditis elegans aging

    Science.gov (United States)

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

    2017-01-01

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

  20. Microvalve-based microfluidic device for C. elegans manipulation

    Science.gov (United States)

    Johari, S.; Nock, V.; Alkaisi, M. M.; Wang, W.

    2017-09-01

    In this paper, we report on the integration of a force measurement application capable of continuously measuring the forces generated by C. elegans in motion with a series of controllable microvalves which have an additional ability to increase control over worm selection and manipulation. The three-layer device consists of a pneumatic layer at the top, and a fluidic layer at the bottom with a thin PDMS membrane which functions as a microvalve sandwiched in between. The pneumatic layer functions as valves, whose operation is controlled pneumatically. The fluidic layer contains of PDMS micropillars for resolving the worm force from the deflection of the cantilever-like pillars. The measured force is horizontal and equivalent to a point force acting at half of the pillar height. By carefully controlling the incorporated microvalves, the proposed device is able to select and direct worm movement and at the same time increase the number of force measurement results collected. The integration of the microvalve with the PDMS micropillar-based on chip system can be easily combined with existing screening and imaging systems and also has the capability to facilitate high-throughput screening of force patterns in C. elegans locomotion behaviour.

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

    Science.gov (United States)

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

    2017-02-28

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

  2. 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.

  3. Concurrent corticosteroid and phenanthrene transformation by filamentous fungus Cunninghamella elegans.

    Science.gov (United States)

    Lisowska, Katarzyna; Długoński, Jerzy

    2003-05-01

    A filamentous fungus Cunninghamella elegans IM 1785/21Gp which displays ability of 17alpha,21-dihydroxy-4-pregnene-3,20-dione (cortexolone) 11-hydroxylation (yielding epihydrocortisone (eF) and hydrocortisone (F)) and polycyclic aromatic hydrocarbons (PAHs) degradation, was used as a microbial eucaryotic model to study the relationships between mammalian steroid hydroxylation and PAHs metabolization. The obtained results showed faster transformation of phenanthrene in Sabouraud medium supplemented with steroid substrate (cortexolone). Simultaneously phenanthrene stimulated epihydrocortisone production from cortexolone. In phenanthrene presence the ratio between cortexolone hydroxylation products (hydrocortisone and epihydrocortisone) was changed from 1:5.1-6.2 to 1:7.6-8.4 in the culture without phenanthrene. Cytochrome P-450 content significantly increased after the culture supplementation by the second substrate, phenanthrene or cortexolone, adequately. To confirm the involvement of cytochrome P-450 in phenanthrene metabolism, the inhibition studies were performed. The cytochrome P-450 inhibitors SKF 525-A (1.5mM) and 2-methyl-1,2-di-3-pyridyl-1-propanone (metyrapone) (2mM) inhibited phenanthrene transformation by 80 and 62%, respectively. 1-aminobenzotriazole (1mM) completely blocked phenanthrene metabolism. The obtained results suggest a presence of connections between steroid hydroxylases and enzymes involved in PAH degradation in C. elegans.

  4. Oxidation of phenothiazine and phenoxazine by Cunninghamella elegans.

    Science.gov (United States)

    Sutherland, J B; Freeman, J P; Heinze, T M; Moody, J D; Parshikov, I A; Williams, A J; Zhang, D

    2001-11-01

    1. To determine the ability of fungi to metabolize sulphur- and oxygen-containing azaarenes, Cunninghamella elegans ATCC 9245 was grown in 125-ml flasks containing fluid Sabouraud medium. The cultures and controls were incubated at 28 degrees C with shaking and dosed with 16.7 mM phenothiazine or phenoxazine. After incubation for 72h, the mycelia and filtrates were extracted with ethyl acetate and the combined residues analysed by high-performance liquid chromatography. Residual phenothiazine and phenoxazine were 21 and 22%, respectively, of the total UV absorbance at 254 nm. 2. The metabolites were identified by mass spectrometry and proton nuclear magnetic resonance spectroscopy. The fungus oxidized phenothiazine to phenothiazine sulphoxide, 3-hydroxyphenothiazine sulphoxide, phenothiazin-3-one, and 3-hydroxyphenothiazine and oxidized phenoxazine to phenoxazin-3-one. 3. Three of the four compounds produced by C. elegans from phenothiazine were identical to those produced by mammals, supporting the use of the fungus as a microbial model for drug metabolism.

  5. Transformation of 1- and 2-methylnaphthalene by Cunninghamella elegans.

    Science.gov (United States)

    Cerniglia, C E; Lambert, K J; Miller, D W; Freeman, J P

    1984-01-01

    Cunninghamella elegans metabolized 1- and 2-methylnaphthalene primarily at the methyl group to form 1- and 2-hydroxymethylnaphthalene, respectively. Other compounds isolated and identified were 1- and 2-naphthoic acids, 5-hydroxy-1-naphthoic acid, 5-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, and phenolic derivatives of 1- and 2-methylnaphthalene. The metabolites were isolated by thin-layer and reverse-phase high-pressure liquid chromatography and characterized by the application of UV-visible absorption, 1H nuclear magnetic resonance, and mass spectral techniques. Experiments with [8-14C]2-methylnaphthalene indicated that over a 72-h period, 9.8% of 2-methylnaphthalene was oxidized to metabolic products. The ratio of organic-soluble in water-soluble metabolites at 2 h was 92:8, and at 72 h it was 41:59. Enzymatic treatment of the 48-h aqueous phase with either beta-glucuronidase or arylsulfatase released 60% of the metabolites of 2-methylnaphthalene that were extractable with ethyl acetate. In both cases, the major conjugates released were 5-hydroxy-2-naphthoic acid and 6-hydroxy-2-naphthoic acid. The ratio of the water-soluble glucuronide conjugates to sulfate conjugates was 1:1. Incubation of C. elegans with 2-methylnaphthalene under an 18O2 atmosphere and subsequent mass spectral analysis of 2-hydroxymethylnaphthalene indicated that hydroxylation of the methyl group is catalyzed by a monooxygenase. PMID:6696408

  6. Metabolism of methoxychlor by Cunninghamella elegans ATCC36112.

    Science.gov (United States)

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

    2009-09-09

    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.

  7. Transformation of 1- and 2-methylnaphthalene by Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    Cerniglia, C.E.; Lambert, K.J.; Miller, D.W.; Freeman, J.P.

    1984-01-01

    Cunninghamella elegans metabolized 1- and 2-methylnaphthalene primarily at the methyl group to form 1- and 2-hydroxymethylnaphthalene, respectively. Other compounds isolated and identified were 1- and 2-naphthoic acids, 5-hydroxy-1-naphthoic acid, 5-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, and phenolic derivatives of 1- and 2-methylnaphthalene. The metabolites were isolated by thin-layer and reverse-phase high-presure liquid chromatography and characterized by the application of UV-visible absorption, /sup 1/H nuclear magnetic resonance, and mass spectral techniques. Experiments with (8-/sup 14/C)2-methylnaphthalene indicated that over a 72-h period, 9.8% of 2-methylnaphthalene was oxidized to metabolic products. The ratio of organic-soluble to water-soluble metabolites at 2 h was 92:8, and at 72 h it was 41:59. Enzymatic treatment of the 48-h aqueous phase with either ..beta..-glucuronidase or arylsufatase released 60% of the metabolites of 2-methylnaphthalene that were extractable with ethyl acetate. In both cases, the major conjugates released were 5-hydroxy-2-naphthoic acid and 6-hydroxy-2-naphthoic acid. The ratio of the water-soluble glucuronide conjugates to sulfate conjugates was 1:1. Incubation of C. elegans with 2-methylnaphthalene under an /sup 18/O/sub 2/ atmosphere and subsequent mass spectral analysis of 2-hydroxymethylnaphthalene indicated that hydroxylation of the methyl group is catalyzed by a monooxygenase. 23 references.

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

    Science.gov (United States)

    Shaham, Shai

    2007-11-07

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

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

    Directory of Open Access Journals (Sweden)

    Shai Shaham

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

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

    Science.gov (United States)

    Papaevgeniou, Nikoletta; Chondrogianni, Niki

    2014-01-01

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

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

    Science.gov (United States)

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

    2017-02-01

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

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

    Science.gov (United States)

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

    2012-10-01

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

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

    Science.gov (United States)

    Nakamura, Itaru; Nagakura, Tomoki; Fujita, Hiroaki; Fukusima, Shinji; Gonoi, Tohru

    2017-01-01

    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. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. The rich club of the C. elegans neuronal connectome.

    Science.gov (United States)

    Towlson, Emma K; Vértes, Petra E; Ahnert, Sebastian E; Schafer, William R; Bullmore, Edward T

    2013-04-10

    There is increasing interest in topological analysis of brain networks as complex systems, with researchers often using neuroimaging to represent the large-scale organization of nervous systems without precise cellular resolution. Here we used graph theory to investigate the neuronal connectome of the nematode worm Caenorhabditis elegans, which is defined anatomically at a cellular scale as 2287 synaptic connections between 279 neurons. We identified a small number of highly connected neurons as a rich club (N = 11) interconnected with high efficiency and high connection distance. Rich club neurons comprise almost exclusively the interneurons of the locomotor circuits, with known functional importance for coordinated movement. The rich club neurons are connector hubs, with high betweenness centrality, and many intermodular connections to nodes in different modules. On identifying the shortest topological paths (motifs) between pairs of peripheral neurons, the motifs that are found most frequently traverse the rich club. The rich club neurons are born early in development, before visible movement of the animal and before the main phase of developmental elongation of its body. We conclude that the high wiring cost of the globally integrative rich club of neurons in the C. elegans connectome is justified by the adaptive value of coordinated movement of the animal. The economical trade-off between physical cost and behavioral value of rich club organization in a cellular connectome confirms theoretical expectations and recapitulates comparable results from human neuroimaging on much larger scale networks, suggesting that this may be a general and scale-invariant principle of brain network organization.

  15. 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.

  16. 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.

  17. 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.

  18. 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

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

    Science.gov (United States)

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

    2011-05-01

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

  20. 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.

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

    Science.gov (United States)

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

    2016-10-01

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

  2. Autophagy Genes Are Essential for Dauer Development and Life-Span Extension in C. elegans

    National Research Council Canada - National Science Library

    Alicia Meléndez; Zsolt Tallóczy; Matthew Seaman; Eeva-Liisa Eskelinen; David H. Hall; Beth Levine

    2003-01-01

    Both dauer formation (a stage of developmental arrest) and adult life-span in Caenorhabditis elegans are negatively regulated by insulin-like signaling, but little is known about cellular pathways that mediate these processes...

  3. Widespread Proteome Remodeling and Aggregation in Aging C. elegans

    National Research Council Canada - National Science Library

    Walther, Dirk M; Kasturi, Prasad; Zheng, Min; Pinkert, Stefan; Vecchi, Giulia; Ciryam, Prajwal; Morimoto, Richard I; Dobson, Christopher M; Vendruscolo, Michele; Mann, Matthias; Hartl, F. Ulrich

    2015-01-01

    .... Here, we profiled more than 5,000 proteins along the lifespan of the nematode C. elegans. We find that one-third of proteins change in abundance at least 2-fold during aging, resulting in a severe proteome imbalance...

  4. Cadmium tolerance and removal from Cunninghamella elegans related to the polyphosphate metabolism

    National Research Council Canada - National Science Library

    de Lima, Marcos A B; Franco, Luciana de O; de Souza, Patrícia M; do Nascimento, Aline E; da Silva, Carlos A A; Maia, Rita de C C; Rolim, Hercília M L; Takaki, Galba M C

    2013-01-01

    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...

  5. Biotransformation of bromhexine by Cunninghamella elegans, C. echinulata and C. blakesleeana

    National Research Council Canada - National Science Library

    Dube, Aman K; Kumar, Maushmi S

    ... in in vitro condition. We aim to screen the most efficient strain of Cunninghamella sp. among C. elegans, C. echinulata and C. blakesleeana for bromhexine metabolites production. We character- ized th...

  6. 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.

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

    Science.gov (United States)

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

    2011-01-01

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

  8. 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.

  9. Phosphorus speciation by {sup 31}P NMR spectroscopy in bracken (Pteridium aquilinum (L.) Kuhn) and bluebell (Hyacinthoides non-scripta (L.) Chouard ex Rothm.) dominated semi-natural upland soil

    Energy Technology Data Exchange (ETDEWEB)

    Ebuele, Victor O.; Santoro, Anna; Thoss, Vera, E-mail: v.thoss@bangor.ac.uk

    2016-10-01

    (Hyacinthoides non-scripta) dominated soil • The main P species detected in bluebell bulbs was myo-IP{sub 6} • Below-ground shedding of old bulb creates accessible P store in soil • Bracken bluebell dominance in the field were determined by their phenology and P speciation.

  10. Molecular Analysis of Tube Cement of the Biofouling Tubeworm Hydroides elegans

    Science.gov (United States)

    2016-03-08

    combination of advanced microscopy, transcriptomics, and molecular biology we will describe: (1) the major molecular components of the compounds...encoding for marine cements in other invertebrates are expressed in tissues of H. elegans. Because the cements of H. elegans show no homology to any...Hadfield, M.G. and B. T, Nedved. (2016). The bacterial basis of larval settlement. Abstract for Society for Integrative and Comparative Biology , Jan

  11. Distinct pathogenesis and host responses during infection of C. elegans by P. aeruginosa and S. aureus.

    Directory of Open Access Journals (Sweden)

    Javier E Irazoqui

    2010-07-01

    Full Text Available 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

  12. An image analysis toolbox for high-throughput C. elegans assays.

    Science.gov (United States)

    Wählby, Carolina; Kamentsky, Lee; Liu, Zihan H; Riklin-Raviv, Tammy; Conery, Annie L; O'Rourke, Eyleen J; Sokolnicki, Katherine L; Visvikis, Orane; Ljosa, Vebjorn; Irazoqui, Javier E; Golland, Polina; Ruvkun, Gary; Ausubel, Frederick M; Carpenter, Anne E

    2012-04-22

    We present a toolbox for high-throughput screening of image-based Caenorhabditis elegans phenotypes. The image analysis algorithms measure morphological phenotypes in individual worms and are effective for a variety of assays and imaging systems. This WormToolbox is available through the open-source CellProfiler project and enables objective scoring of whole-worm high-throughput image-based assays of C. elegans for the study of diverse biological pathways that are relevant to human disease.

  13. 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

    2010-07-01

    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

  14. Selective visualization of fluorescent sterols in Caenorhabditis elegans by bleach-rate-based image segmentation

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Landt Larsen, Ane; Færgeman, Nils J.

    2010-01-01

    The nematode Caenorhabditis elegans is a genetically tractable model organism to investigate sterol transport. In vivo imaging of the fluorescent sterol, dehydroergosterol (DHE), is challenged by C. elegans' high autofluorescence in the same spectral region as emission of DHE. We present a method...... homologues of Niemann-Pick C disease proteins. Our approach is generally useful for identifying fluorescent probes in the presence of high cellular autofluorescence....

  15. 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.

  16. Cloning, sequencing, and expression in Escherichia coli of a cytochrome P450 gene from Cunninghamella elegans.

    Science.gov (United States)

    Wang, R F; Cao, W W; Khan, A A; Cerniglia, C E

    2000-07-01

    A polyclonal antibody against microsomes of a fungus, Cunninghamella elegans, was used to screen a C. elegans cDNA library. A cDNA clone, containing an open reading frame (ORF) encoding a protein of 389 amino acids (aa), was obtained. GenBank comparison (BLAST) showed that the protein was closely related to P450 because a heme-binding region, which is highly conserved in all P450 sequences, was found in the ORF protein. Using an oligo probe designed from this C. elegans heme-binding region to rescreen the cDNA library, we obtained three new clones. Sequence comparison showed that the three clones, with different length cDNA inserts, were from the same mRNA of the C. elegans P450 gene. One clone had the full C. elegans P450 gene, encoding 473 aa with a molecular mass of 54958.60, whereas the 389 was a part of the 473 aa without the N-terminal. The entire C. elegans P450 gene was successfully subcloned and overexpressed in a plasmid-Escherichia coli system (pQE30). Immunostaining with three antibodies (CYP1A1, CYP2E1, and CYP3A1) against mammalian P450 enzymes and benzidine staining for hemoproteins showed positive results for the recombinant protein expressed in E. coli. A phylogenetic tree was constructed by comparison of other fungal P450s to the C. elegans sequence. The C. elegans P450 clustered close to the cyp51 family and was named cyp509A1 by the International Committee on the Nomenclature for Cytochrome P450 Enzymes.

  17. O-demethylation and sulfation of 7-methoxylated flavanones by Cunninghamella elegans.

    Science.gov (United States)

    Ibrahim, Abdel-Rahim Sayed; Galal, Ahmed Mohamed; Ahmed, Mohammed Shamim; Mossa, Gabir Salem

    2003-02-01

    Metabolism of 7-O-methylnaringenin (sakuranetin) by Cunninghamella elegans NRRL 1392 yielded naringenin and naringenin-4'-sulfate. C. elegans also converted 5, 3', 4'-trihydroxy-7-methoxyflavanone into eriodictyol-4'-sulfate. Furthermore, incubation of 5, 4'-dihydroxy-7, 3'-dimethoxyflavanone with the same fungus gave homoeriodictyol (5, 7, 4'-trihydroxy-3'-methoxyflavanone) and homoeriodicytol-7-sulfate. The structures of the new metabolites were established by spectral analysis including 2D-NMR, HR-ESI-FT-MS beside hydrolysis by acid.

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

    OpenAIRE

    Hercília M. L. Rolim; Rita C.C. Maia; da Silva, Carlos A. A.; do Nascimento, Aline E.; de Souza, Patrícia M.; Franco, Luciana O.; Marcos A. B. de Lima; Takaki, Galba M. C.

    2013-01-01

    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 du...

  19. Screening lifespan-extending drugs in Caenorhabditis elegans via label propagation on drug-protein networks.

    Science.gov (United States)

    Liu, Hui; Guo, Mengmeng; Xue, Ting; Guan, Jihong; Luo, Libo; Zhuang, Ziheng

    2016-12-23

    One of the most challenging tasks in the exploration of anti-aging is to discover drugs that can promote longevity and delay the incidence of age-associated diseases of human. Up to date, a number of drugs, including some antioxidants, metabolites and synthetic compounds, have been found to effectively delay the aging of nematodes and insects. We proposed a label propagation algorithm on drug-protein network to infer drugs that can extend the lifespan of C. elegans. We collected a set of drugs of which functions on lifespan extension of C. elegans have been reliably determined, and then built a large-scale drug-protein network by collecting a set of high-confidence drugprotein interactions. A label propagation algorithm was run on the drug-protein bipartite network to predict new drugs with lifespan-extending effect on C. elegans. We calibrated the performance of the proposed method by conducting performance comparison with two classical models, kNN and SVM. We also showed that the screened drugs significantly mediate in the aging-related pathways, and have higher chemical similarities to the effective drugs than ineffective drugs in promoting longevity of C. elegans. Moreover, we carried out wet-lab experiments to verify a screened drugs, 2- Bromo-4'-nitroacetophenone, and found that it can effectively extend the lifespan of C. elegans. These results showed that our method is effective in screening lifespanextending drugs in C. elegans. In this paper, we proposed a semi-supervised algorithm to predict drugs with lifespan-extending effects on C. elegans. In silico empirical evaluations and in vivo experiments in C. elegans have demonstrated that our method can effectively narrow down the scope of candidate drugs needed to be verified by wet lab experiments.

  20. Records of Narcissus Elegans (fam. Amaryllidaceae) and notes on the wild Narcissus in the Maltese Islands

    OpenAIRE

    Mifsud, Stephen; Caruana, Emanuel

    2010-01-01

    Substantiated records of Narcissus elegans are reported from Malta and for the first time in Gozo. Habitat and ecological analysis of the three different populations and a distribution map is given. Morphological characters between the populations are compared between each other and the described taxa. Also discussed and illustrated are the intermediate range of specimens found in Malta between N. serotinus, N. elegans and N. tazetta.

  1. 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...

  2. History of research on C. elegans and other free-living nematodes as model organisms.

    Science.gov (United States)

    Nigon, Victor Marc; Félix, Marie-Anne

    2017-01-01

    The nematode Caenorhabditis elegans is now a major model organism in biology. The choice of Sydney Brenner to adopt this species in the mid-1960s and the success of his team in raising it to a model organism status have been told (http://www.wormbook.org/toc_wormhistory.html; Brenner, 2001; Ankeny, 2001). Here we review the pre-Brenner history of the use of free-living nematodes as models for general questions in biology. We focus on the period that started in 1899 with the first publication of Emile Maupas mentioning Rhabditis elegans and ended in 1974 with the first publications by Brenner. A common thread in this period, aided by the variety in modes of reproduction of different nematode species, is found in studies of meiosis, fertilization, heredity, and sex determination. Maupas in his 1900 opus on reproduction had already chosen C. elegans as the species of reference. Hikokura Honda determined its hermaphrodite chromosomal content in 1925. C. elegans was again isolated and chosen as a main subject by Victor Nigon in the 1940-50s. Nigon mastered crosses between C. elegans hermaphrodites and males, described the meiotic behavior of chromosomes in XX hermaphrodites and X0 males and, using tetraploids, correctly inferred that sex was determined by X chromosome to autosome dosage. With Ellsworth Dougherty, Nigon isolated and studied a C. briggsae body size mutant and a C. elegans slow growth mutant. Dougherty and his team devoted most of their work to finding a defined culture medium to screen for physiological mutants, focusing on C. briggsae. With Helene Fatt, Dougherty also performed the first genetic study of natural variation in C. elegans, concerning the difference in heat resistance of the Bergerac and Bristol strains. Jean Brun, a student of Nigon, performed a long and remarkable experiment in acclimatization of C. elegans Bergerac to higher temperatures, the significance of which remains to be clarified. PMID:28326696

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

    Science.gov (United States)

    Barr, Maureen M

    2005-02-01

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

  4. The control structure of the nematode Caenorhabditis elegans: neuro-sensory integration and propioceptive feedback

    OpenAIRE

    Fieseler, Charles; Kunert-Graf, James; Kutz, J. Nathan

    2017-01-01

    We develop a biophysically realistic model of the nematode C. elegans that includes: (i) its muscle structure and activation, (ii) key connectomic activation circuitry, and (iii) a weighted and time-dynamic propioception. In combination, we show that these model components can reproduce the complex waveforms exhibited in C. elegans locomotive behaviors, such as omega turns. We show that weighted, time-dependent synaptic dynamics are necessary for this complex behavior, ultimately revealing ke...

  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. Pheromone modulates two phenotypically plastic traits - adult reproduction and larval diapause - in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Wharam, Barney; Weldon, Laura; Viney, Mark

    2017-08-22

    Animals use information from their environment to make decisions, ultimately to maximize their fitness. The nematode C. elegans has a pheromone signalling system, which hitherto has principally been thought to be used by worms in deciding whether or not to arrest their development as larvae. Recent studies have suggested that this pheromone can have other roles in the C. elegans life cycle. Here we demonstrate a new role for the C. elegans pheromone, showing that it accelerates hermaphrodites' reproductive rate, a phenomenon which we call pheromone-dependent reproductive plasticity (PDRP). We also find that pheromone accelerates larval growth rates, but this depends on a live bacterial food source, while PDRP does not. Different C. elegans strains all show PDRP, though the magnitude of these effects differ among the strains, which is analogous to the diversity of arrested larval phenotypes that this pheromone also induces. Using a selection experiment we also show that selection for PDRP or for larval arrest affects both the target and the non-target trait, suggesting that there is cross-talk between these two pheromone-dependent traits. Together, these results show that C. elegans' pheromone is a signal that acts at two key life cycle points, controlling alternative larval fates and affecting adult hermaphrodites' reproduction. More broadly, these results suggest that to properly understand and interpret the biology of pheromone signalling in C. elegans and other nematodes, the life-history biology of these organisms in their natural environment needs to be considered.

  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. Stimulation of host immune defenses by a small molecule protects C. elegans from bacterial infection.

    Directory of Open Access Journals (Sweden)

    Read Pukkila-Worley

    Full Text Available 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 the host immune response of the nematode. Using transcriptome profiling, epistasis pathway analyses with C. elegans mutants, and an RNAi screen, we show that RPW-24 promotes resistance to Pseudomonas aeruginosa infection by inducing the transcription of a remarkably small number of C. elegans genes (∼1.3% of all genes in a manner that partially depends on the evolutionarily-conserved p38 MAP kinase pathway and the transcription factor ATF-7. These data show that the immunostimulatory activity of RPW-24 is required for its efficacy and define a novel C. elegans-based strategy to identify compounds with activity against antibiotic-resistant bacterial pathogens.

  9. Stimulation of host immune defenses by a small molecule protects C. elegans from bacterial infection.

    Science.gov (United States)

    Pukkila-Worley, Read; Feinbaum, Rhonda; Kirienko, Natalia V; Larkins-Ford, Jonah; 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 the host immune response of the nematode. Using transcriptome profiling, epistasis pathway analyses with C. elegans mutants, and an RNAi screen, we show that RPW-24 promotes resistance to Pseudomonas aeruginosa infection by inducing the transcription of a remarkably small number of C. elegans genes (∼1.3% of all genes) in a manner that partially depends on the evolutionarily-conserved p38 MAP kinase pathway and the transcription factor ATF-7. These data show that the immunostimulatory activity of RPW-24 is required for its efficacy and define a novel C. elegans-based strategy to identify compounds with activity against antibiotic-resistant bacterial pathogens.

  10. 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.

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

    Science.gov (United States)

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

    2016-03-01

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

  12. Stereoselective metabolism of anthracene and phenanthrene by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Cerniglia, C E; Yang, S K

    1984-01-01

    The fungus Cunninghamella elegans oxidized anthracene and phenanthrene to form predominately trans-dihydrodiols. The metabolites were isolated by reversed-phase high-pressure liquid chromatography for structural and conformational analyses. Comparison of the circular dichroism spectrum of the fungal trans-1,2-dihydroxy-1,2-dihydroanthracene to that formed by rat liver microsomes indicated that the major enantiomer of the trans-1,2-dihydroxy-1,2-dihydroanthracene formed by C. elegans had an S,S absolute stereochemistry, which is opposite to the predominately 1R,2R dihydrodiol formed by rat liver microsomes. C. elegans oxidized phenanthrene primarily in the 1,2-positions to form trans-1,2-dihydroxy-1,2-dihydrophenanthrene. In addition, a minor amount of trans-3,4-dihydroxy-3,4-dihydrophenanthrene was detected. Metabolism at the K-region (9,10-positions) of phenanthrene was not detected. Comparison of the circular dichroism spectra of the phenanthrene trans-1,2- and trans-3,4-dihydrodiols formed by C. elegans to those formed by mammalian enzymes indicated that each of the dihydrodiols formed by C. elegans had an S,S absolute configuration. The results indicate that there are differences in both the regio- and stereoselective metabolism of anthracene and phenanthrene between the fungus C. elegans and rat liver microsomes. PMID:6696409

  13. Locomotion and Body Shape Changes of Metabolically Different C.elegans in Fluids with Varying Viscosities

    Science.gov (United States)

    Wong, Rachel; Brenowitz, Noah; Shen, Amy

    2010-11-01

    Caenorhabditis elegans (C.elegans) are soil dwelling roundworms that have served as model organisms for studying a multitude of biological and engineering phenomena. On agar, the locomotion of the worm is sinusoidal, while in water, the swimming motion of the worm appears more episodic. The efficiency of the worm locomotion is tested by placing the worm in four fluids with varying viscosities. We quantify the locomotion pattern variations by categorizing the swimming kinematics and shapes of the C.elegans. The locomotion of two mutants C.elegans and a control C.elegans was tested: daf2, nhr49, and N2 Wildtype. The metabolic effects of the worms are evaluated by focusing on the forward swimming velocity, wavelength, amplitude and swimming frequency were compared. Using these measured values, we were able to quantify the efficiency, the speed of propagation of the wave along the body resulting in forward movement (wave velocity), and transverse velocity, defined as the amplitude times the frequency, of the worm locomotion. It was shown that C.elegans has a preferential swimming shape that adapts as the environment changes regardless of its efficiency.

  14. Stereoselective metabolism of anthracene and phenanthrene by the fungus Cunninghamella elegans

    Energy Technology Data Exchange (ETDEWEB)

    Cerniglia, C.E.; Yang, S.K.

    1984-01-01

    The fungus Cunninghamella elegans oxidized anthracene and phenanthrene to form predominately transdihydrodiols. The metabolites were isolated by reversed-phase high-pressure liquid chromatography for structural and conformational analyses. Comparison of the circular dichroism spectrum of the fungal trans-1,2-dihydroxy-1,2-dihydroanthracene to that formed by rat liver microsomes indicated that the major enantiomer of the trans-1,2-dihydroxy-1,2-dihydroanthracene formed by C. elegans had an S,S absolute stereochemistry, which is opposite to the predominately 1R,2R dihydrodiol formed by rat liver microsomes. C. elegans oxidized phenanthrene primarily in the 1,2-positions to form trans-1,2-dihydroxy-1,2-dihydrophenanthrene. In addition, a minor amount of trans-3,4-dihydroxy-3,4-dihydrophenanthrene was detected. Metabolism at the K-region (9,10-positions) of phenanthrene was not detected. Comparison of the circular dichroism spectra of the phenanthrene trans-1,2- and trans-3,4-dihydrodiols formed by C. elegans to those formed by mammalian enzymes indicated that each of the dihydrodiols formed by C. elegans had an S,S absolute configuration. The results indicate that there are differences in both the regio- and stereoselective metabolism of anthracene and phenanthrene between the fungus C. elegans and rat liver microsomes. 26 references.

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

    Science.gov (United States)

    Okkema, P G

    2017-01-01

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

  16. 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.

  17. Realgar bioleaching solution suppress ras excessive activation by increasing ROS in Caenorhabditis elegans.

    Science.gov (United States)

    Zhi, De Juan; Feng, Na; Liu, Dong Ling; Hou, Rong Li; Wang, Mei Zu; Ding, Xiao Xia; Li, Hong Yu

    2014-03-01

    Although realgar bioleaching solution (RBS) has been proved to be a potential candidate for cancer therapy, the mechanisms of RBS anticancer are still far from being completely understood. Dosed with RBS in C. elegans, the multivulva phenotype resulting from oncogenic ras gain-of-function was inhibited in a dose dependent manner. It could be abrogated by concurrent treatment C. elegans with RBS and the radical scavenger DMSO. However, RBS could not induce DAF-16 nuclear translocation in TJ356 or the increase of HSP 16.2 expression in CL2070, which both could be aroused visible GFP fluorescent variation to represent for oxidative stress generation. Treatment C. elegans with superoxide anion generator paraquat, similar results were also obtained. Our results indicated that RBS suppress excessive activated ras by increasing reactive oxygen species (ROS) in C. elegans. Secondly, ROS induced by RBS significantly accumulated on a higher level in C. elegans with a mutational ras than that with wild ras, thus leading to oxidative stress on ras gain-of-function background rather than on normal ras context. Our results firstly demonstrated that using C. elegans as a model organism for evaluating prooxidant drug candidates for cancer therapy.

  18. 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.

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

    Science.gov (United States)

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

    2010-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

  1. Microtubule-dependent ribosome localization in C. elegans neurons

    Science.gov (United States)

    Noma, Kentaro; Goncharov, Alexandr; Ellisman, Mark H

    2017-01-01

    Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons. PMID:28767038

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. A quantifiably complete repertoire of C. elegans locomotion

    Science.gov (United States)

    Brown, Andre; Schwarz, Roland; Branicky, Robyn; Schafer, William

    2014-03-01

    Visible phenotypes have played a critical role in understanding the molecular basis of behaviour in model organisms. However, most current descriptions of behaviour are based on manually identified events or a limited set of quantitative parameters. Here we report an extension of the concept of behavioural motifs to exhaustively catalogue C. elegans locomotion and derive a repertoire that is quantifiably complete. A repertoire learned for spontaneous behaviour in wild-type worms can be used to fit data from mutants or worms in different environmental conditions and provides a sensitive measure of phenotypic similarity. Repertoire comparison can also be used to assess inter-individual variation and the compositionality of behaviour, that is, the extent to which behavioural adaptation involves the creation of novel repertoire elements or the reuse of existing elements in novel sequences. Repertoire derivation is general, so that given a representation of posture, our approach will apply to other organisms.

  4. 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.

  5. Tyrosylprotein sulfotransferase regulates collagen secretion in Caenorhabditis elegans.

    Science.gov (United States)

    Kim, Tai Hoon; Kim, Do Hyun; Nam, Hyung Wook; Park, Sang Yoon; Shim, Jaegal; Cho, Jin Won

    2010-04-01

    The sulfation of tyrosine residues is an important post-translational modification involved in the regulation of protein function. We examined the activity of worm tyrosylprotein sulfotransferase (TPST-1) on a typical cuticle collagen, ROL-6, in C. elegans. We verified that TPST-1 sulfates three tyrosine residues of ROL-6 in vitro. We found that these tyrosine residues are important for the secretion of ROL-6::GFP. Mutant ROL-6::GFP proteins that contain more than two substitutions of the target tyrosine residues are severely deficient in cuticle localization. Consistently, knock down of tpst-1 blocked the cuticle localization of ROL-6::GFP. Therefore, the sulfation of ROL-6 by TPST-1 is critical for the proper localization of ROL-6. We also confirmed that worm TPST-1 is localized to the trans-Golgi network (TGN). Our results indicate that TPST-1 regulates cuticle organization by promoting the transport of ROL-6 from the TGN to the cuticle.

  6. A factorial design analysis of chitin production by Cunninghamella elegans.

    Science.gov (United States)

    Andrade, V S; Neto, B B; Souza, W; Campos-Takaki, G M

    2000-11-01

    Chitin production by Cunninghamella elegans (IFM 46109) was studied with a two-level full factorial design, varying time of cultivation and the concentration of D-glucose, L-asparagine, and thiamine in the culture medium. The material extracted was characterized by infrared and NMR spectroscopy. The highest chitin yield, 28.8%, was comparable with the highest in the literature and was obtained with a medium containing 60 g.L-1 of glucose, 3 g.L-1 of asparagine, and 0.008 mg.L-1 of thiamine. Increasing the time of cultivation from 24 h to 72 h did not affect chitin production. The three factors showed significant positive effects on chitin production, without interactions between them.

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

    Science.gov (United States)

    Waaijers, Selma; Boxem, Mike

    2014-08-01

    The development in early 2013 of CRISPR/Cas9-based genome engineering promises to dramatically advance our ability to alter the genomes of model systems at will. A single, easily produced targeting RNA guides the Cas9 endonuclease to a specific DNA sequence where it creates a double strand break. Imprecise repair of the break can yield mutations, while homologous recombination with a repair template can be used to effect specific changes to the genome. The tremendous potential of this system led several groups to independently adapt it for use in Caenorhabditiselegans, where it was successfully used to generate mutations and to create tailored genome changes through homologous recombination. Here, we review the different approaches taken to adapt CRISPR/Cas9 for C. elegans, and provide practical guidelines for CRISPR/Cas9-based genome engineering. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2009-01-01

    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 understand the molecular bases of these activities, we identified 298 genes whose mRNAs are glia-enriched. One gene, fig-1, encodes a labile protein with conserved thrombospondin TSP1 domains. FIG-1 protein functions extracellularly, is essential for neuronal dye uptake, and also affects behavior. Our results suggest that glia are required for multiple aspects of sensory organ function. PMID:18974354

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

    Science.gov (United States)

    Gjorgjieva, Julijana; Biron, David; Haspel, Gal

    2014-01-01

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

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Read Pukkila-Worley

    2011-06-01

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

  12. Sequence signatures of nucleosome positioning in Caenorhabditis elegans.

    Science.gov (United States)

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

    2010-06-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  14. Malate and fumarate extend lifespan in Caenorhabditis elegans.

    Science.gov (United States)

    Edwards, Clare B; Copes, Neil; Brito, Andres G; Canfield, John; Bradshaw, Patrick C

    2013-01-01

    Malate, the tricarboxylic acid (TCA) cycle metabolite, increased lifespan and thermotolerance in the nematode C. elegans. Malate can be synthesized from fumarate by the enzyme fumarase and further oxidized to oxaloacetate by malate dehydrogenase with the accompanying reduction of NAD. Addition of fumarate also extended lifespan, but succinate addition did not, although all three intermediates activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced oxidative stress. The glyoxylate shunt, an anabolic pathway linked to lifespan extension in C. elegans, reversibly converts isocitrate and acetyl-CoA to succinate, malate, and CoA. The increased longevity provided by malate addition did not occur in fumarase (fum-1), glyoxylate shunt (gei-7), succinate dehydrogenase flavoprotein (sdha-2), or soluble fumarate reductase F48E8.3 RNAi knockdown worms. Therefore, to increase lifespan, malate must be first converted to fumarate, then fumarate must be reduced to succinate by soluble fumarate reductase and the mitochondrial electron transport chain complex II. Reduction of fumarate to succinate is coupled with the oxidation of FADH2 to FAD. Lifespan extension induced by malate depended upon the longevity regulators DAF-16 and SIR-2.1. Malate supplementation did not extend the lifespan of long-lived eat-2 mutant worms, a model of dietary restriction. Malate and fumarate addition increased oxygen consumption, but decreased ATP levels and mitochondrial membrane potential suggesting a mild uncoupling of oxidative phosphorylation. Malate also increased NADPH, NAD, and the NAD/NADH ratio. Fumarate reduction, glyoxylate shunt activity, and mild mitochondrial uncoupling likely contribute to the lifespan extension induced by malate and fumarate by increasing the amount of oxidized NAD and FAD cofactors.

  15. Metabolome and proteome changes with aging in Caenorhabditis elegans

    Science.gov (United States)

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

    2015-01-01

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

  16. A transcribed polyketide synthase gene from Xanthoria elegans.

    Science.gov (United States)

    Brunauer, Georg; Muggia, Lucia; Stocker-Wörgötter, Elfie; Grube, Martin

    2009-01-01

    We characterize the transcript of a polyketide synthase gene (PKS) from the cultured mycobiont of Xanthoria elegans (XePKS1) using SMART-rapid amplification of cDNA ends (RACE) cDNA synthesis. Sequence analysis of the cloned cDNA reveals an open reading frame of 2144 amino acid residues. It contains features of a non-reducing fungal type I PKS with an N-terminal starter unit: acyl carrier protein (ACP) transacetylase domain, ketosynthase, acyltransferase, two acyl carrier protein domains, and a thioesterase domain. XePKS1 was the only paralogue detected in the cDNA and the genomic DNA of the cultured X. elegans mycobiont by using a degenerate PCR approach targeted at the conserved regions of non-reducing type I PKS genes. The hypothetical protein is phylogenetically related to genes that are basal to a clade of dihydroxynaphthalene synthases (non-reducing clade II) and anthraquinone type synthases of non-lichenized fungi (non-reducing clade I). According to hplc and tlc analyses, the cultured mycobiont exclusively produced anthraquinones and its precursors. Therefore, we discuss whether the characterized paralogue is involved in anthraquinone production, which raises the possibility of a paraphyletic origin of lichen anthraquinone biosynthesis. The cDNA of XePKS1 was the first full-length coding sequence of a lichen PKS to be published. This proves SMART RACE to be a suitable tool for obtaining full-length coding sequences of genes from environmental samples and organisms, which are hardly amenable to standard molecular approaches or genomic sequencing.

  17. Malate and fumarate extend lifespan in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Clare B Edwards

    Full Text Available Malate, the tricarboxylic acid (TCA cycle metabolite, increased lifespan and thermotolerance in the nematode C. elegans. Malate can be synthesized from fumarate by the enzyme fumarase and further oxidized to oxaloacetate by malate dehydrogenase with the accompanying reduction of NAD. Addition of fumarate also extended lifespan, but succinate addition did not, although all three intermediates activated nuclear translocation of the cytoprotective DAF-16/FOXO transcription factor and protected from paraquat-induced oxidative stress. The glyoxylate shunt, an anabolic pathway linked to lifespan extension in C. elegans, reversibly converts isocitrate and acetyl-CoA to succinate, malate, and CoA. The increased longevity provided by malate addition did not occur in fumarase (fum-1, glyoxylate shunt (gei-7, succinate dehydrogenase flavoprotein (sdha-2, or soluble fumarate reductase F48E8.3 RNAi knockdown worms. Therefore, to increase lifespan, malate must be first converted to fumarate, then fumarate must be reduced to succinate by soluble fumarate reductase and the mitochondrial electron transport chain complex II. Reduction of fumarate to succinate is coupled with the oxidation of FADH2 to FAD. Lifespan extension induced by malate depended upon the longevity regulators DAF-16 and SIR-2.1. Malate supplementation did not extend the lifespan of long-lived eat-2 mutant worms, a model of dietary restriction. Malate and fumarate addition increased oxygen consumption, but decreased ATP levels and mitochondrial membrane potential suggesting a mild uncoupling of oxidative phosphorylation. Malate also increased NADPH, NAD, and the NAD/NADH ratio. Fumarate reduction, glyoxylate shunt activity, and mild mitochondrial uncoupling likely contribute to the lifespan extension induced by malate and fumarate by increasing the amount of oxidized NAD and FAD cofactors.

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Yin Changxin

    2009-05-01

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

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

    Science.gov (United States)

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

    2009-05-20

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-25

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

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Verba volant, scripta manent / Milvi Tedremaa

    Index Scriptorium Estoniae

    Tedremaa, Milvi, 1937-2012

    1999-01-01

    Rets. rmt.: Meie õppisime raamatukogundust Tartu Ülikoolis / koost. Maare Kümnik, Kaja Noodla. Tartu, 1998. Vastukaja: Peep, Laine. Mitte ainult Milvi Tedremaale // Raamatukogu (1999) nr. 4, lk. 44

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

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    Sgro Jean-Yves

    2006-11-01

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

  7. Trans-splicing and operons in C. elegans.

    Science.gov (United States)

    Blumenthal, Thomas

    2012-11-20

    About 70% of C. elegans mRNAs are trans-spliced to one of two 22 nucleotide spliced leaders. SL1 is used to trim off the 5' ends of pre-mRNAs and replace them with the SL1 sequence. This processing event is very closely related to cis-splicing, or intron removal. The SL1 sequence is donated by a 100 nt small nuclear ribonucleoprotein particle (snRNP), the SL1 snRNP. This snRNP is structurally and functionally similar to the U snRNAs (U1, U2, U4, U5 and U6) that play key roles in intron removal and trans-splicing, except that the SL1 snRNP is consumed in the process. More than half of C. elegans pre-mRNAs are subject to SL1 trans-splicing, whereas ~30% are not trans-spliced. The remaining genes are trans-spliced by SL2, which is donated by a similar snRNP, the SL2 snRNP. SL2 recipients are all downstream genes in closely spaced gene clusters similar to bacterial operons. They are transcribed from a promoter at the 5' end of the cluster of between 2 and 8 genes. This transcription makes a polycistronic pre-mRNA that is co-transcriptionally processed by cleavage and polyadenylation at the 3' end of each gene, and this event is closely coupled to the SL2 trans-splicing event that occurs only ~100 nt further downstream. SL2 trans-splicing requires a sequence between the genes, the Ur element, that likely base pairs with the 5' splice site on the SL2 snRNP, in a manner analogous to the interaction between the 5' splice site in cis-splicing with the U1 snRNP. The key difference is that in trans-splicing, the snRNP contains the 5' splice site, whereas in cis-splicing the pre-mRNA does. Some operons, termed "hybrid operons", contain an additional promoter between two genes that can express the downstream gene or genes with a developmental profile that is different from that of the entire operon. The operons contain primarily genes required for rapid growth, including genes whose products are needed for mitochondrial function and the basic machinery of gene expression

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

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    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.

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

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    Sandeep Kumar

    2016-02-01

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

  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

  11. A Conserved Function of C. elegans CASY-1 Calsyntenin in Associative Learning

    Science.gov (United States)

    Hoerndli, Frédéric J.; Walser, Michael; Fröhli Hoier, Erika; de Quervain, Dominique; Papassotiropoulos, Andreas; Hajnal, Alex

    2009-01-01

    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. PMID:19287492

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

    Science.gov (United States)

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

    2012-05-01

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

  13. A conserved function of C. elegans CASY-1 calsyntenin in associative learning.

    Directory of Open Access Journals (Sweden)

    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.

  14. 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.

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

    Science.gov (United States)

    Park, Sojin; Choi, Seoyun; Ahn, Byungchan

    2016-01-01

    DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents. PMID:26903030

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

    Science.gov (United States)

    Park, Sojin; Choi, Seoyun; Ahn, Byungchan

    2016-03-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  19. 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.

  20. 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.

  1. 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.

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

    Science.gov (United States)

    Shaham, Shai

    2015-01-08

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

  3. 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.

  4. 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..

  5. 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.

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

    Science.gov (United States)

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

    2017-02-02

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

  7. Syndecan regulates cell migration and axon guidance in C. elegans.

    Science.gov (United States)

    Rhiner, Christa; Gysi, Stephan; Fröhli, Erika; Hengartner, Michael O; Hajnal, Alex

    2005-10-01

    During nervous system development, axons that grow out simultaneously in the same extracellular environment are often sorted to different target destinations. As there is only a restricted set of guidance cues known, regulatory mechanisms are likely to play a crucial role in controlling cell migration and axonal pathfinding. Heparan sulfate proteoglycans (HSPGs) carry long chains of differentially modified sugar residues that have been proposed to encode specific information for nervous system development. Here, we show that the cell surface proteoglycan syndecan SDN-1 functions autonomously in neurons to control the neural migration and guidance choices of outgrowing axons. Epistasis analysis suggests that heparan sulfate (HS) attached to SDN-1 can regulate guidance signaling by the Slit/Robo pathway. Furthermore, SDN-1 acts in parallel with other HSPG core proteins whose HS side chains are modified by the C5-epimerase HSE-5, and/or the 2O-sulfotransferase HST-2, depending on the cellular context. Taken together, our experiments show that distinct HS modification patterns on SDN-1 are involved in regulating axon guidance and cell migration in C. elegans.

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

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    Henrique Teotonio

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

  9. Determining the biomechanics of touch sensation in C. elegans.

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    Elmi, Muna; Pawar, Vijay M; Shaw, Michael; Wong, David; Zhan, Haoyun; Srinivasan, Mandayam A

    2017-09-26

    The sense of touch is a fundamental mechanism that nearly all organisms use to interact with their surroundings. However, the process of mechanotransduction whereby a mechanical stimulus gives rise to a neuronal response is not well understood. In this paper we present an investigation of the biomechanics of touch using the model organism C. elegans. By developing a custom micromanipulation and force sensing system around a high resolution optical microscope, we measured the spatial deformation of the organism's cuticle and force response to controlled uniaxial indentations. We combined these experimental results with anatomical data to create a multilayer computational biomechanical model of the organism and accurately derive its material properties such as the elastic modulus and poisson's ratio. We demonstrate the utility of this model by combining it with previously published electrophysiological data to provide quantitative insights into different biomechanical states for mechanotransduction, including the first estimate of the sensitivity of an individual mechanoreceptor to an applied stimulus (parameterised as strain energy density). We also interpret empirical behavioural data to estimate the minimum number of mechanoreceptors which must be activated to elicit a behavioural response.

  10. Quantification of Nociceptive Escape Response in C.elegans

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    Leung, Kawai; Mohammadi, Aylia; Ryu, William; Nemenman, Ilya

    2013-03-01

    Animals cannot rank and communicate their pain consciously. Thus in pain studies on animal models, one must infer the pain level from high precision experimental characterization of behavior. This is not trivial since behaviors are very complex and multidimensional. Here we explore the feasibility of C.elegans as a model for pain transduction. The nematode has a robust neurally mediated noxious escape response, which we show to be partially decoupled from other sensory behaviors. We develop a nociceptive behavioral response assay that allows us to apply controlled levels of pain by locally heating worms with an IR laser. The worms' motions are captured by machine vision programming with high spatiotemporal resolution. The resulting behavioral quantification allows us to build a statistical model for inference of the experienced pain level from the behavioral response. Based on the measured nociceptive escape of over 400 worms, we conclude that none of the simple characteristics of the response are reliable indicators of the laser pulse strength. Nonetheless, a more reliable statistical inference of the pain stimulus level from the measured behavior is possible based on a complexity-controlled regression model that takes into account the entire worm behavioral output. This work was partially supported by NSF grant No. IOS/1208126 and HFSP grant No. RGY0084/2011.

  11. 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.

  12. Flow analysis of the low Reynolds number swimmer C. elegans

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    Montenegro-Johnson, Thomas D.; Gagnon, David A.; Arratia, Paulo E.; Lauga, Eric

    2016-09-01

    Swimming cells and microorganisms are a critical component of many biological processes. In order to better interpret experimental studies of low Reynolds number swimming, we combine experimental and numerical methods to perform an analysis of the flow field around the swimming nematode Caenorhabditis elegans. We first use image processing and particle tracking velocimetry to extract the body shape, kinematics, and flow fields around the nematode. We then construct a three-dimensional model using the experimental swimming kinematics and employ a boundary element method to simulate flow fields, obtaining very good quantitative agreement with experiment. We use this numerical model to show that calculation of flow shear rates using purely planar data results in significant underestimates of the true three-dimensional value. Applying symmetry arguments, validated against numerics, we demonstrate that the out-of-plane contribution can be accounted for via incompressibility and therefore simply calculated from particle tracking velocimetry. Our results show how fundamental fluid mechanics considerations may be used to improve the accuracy of measurements in biofluiddynamics.

  13. Dynamic range in the C. elegans brain network

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    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.

  14. Deep SAGE analysis of the Caenorhabditis elegans transcriptome.

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    Ruzanov, Peter; Riddle, Donald L

    2010-06-01

    We employed the Tag-seq technique to generate global transcription profiles for different strains and life stages of the nematode C. elegans. Tag-seq generates cDNA tags as does Serial Analysis of Gene Expression (SAGE), but the method yields a much larger number of tags, generating much larger data sets than SAGE. We examined differences in the performance of SAGE and Tag-seq by comparing gene expression data for 13 pairs of libraries. We identified genes for which expression was consistently changed in long-lived worms. Additional genes emerged in the deeper Tag-seq profiles, including several 'signature' genes found among those zup-regulated in long-lived dauer larvae (cki-1, aak-2 and daf-16). Fifty to sixty percent of the genes differentially expressed in daf-2(-) versus daf-2(+) adults had fragmentary or no functional annotation, suggesting the involvement of as yet unstudied pathways in aging. We were able to distinguish between changes in gene expression associated with altered genotype or altered growth conditions. We found 62 cases of possible mRNA isoform switching in the 13 Tag-seq libraries, whereas the 13 SAGE libraries allowed detection of only 15 such occurrences. We observed strong expression of anti-sense transcripts for several mitochondrial genes, but nuclear anti-sense transcripts were neither abundant nor consistently expressed among the libraries.

  15. Essential roles of snap-29 in C. elegans

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    Kang, Junsu; Bai, Zhiyong; Zegarek, Matthew H.; Grant, Barth D.; Lee, Junho

    2011-01-01

    SNARE domain proteins are key molecules mediating intracellular fusion events. SNAP25 family proteins are unique target-SNAREs possessing two SNARE domains. Here we report the genetic, molecular, and cell biological characterization of C. elegans SNAP-29. We found that snap-29 is an essential gene required throughout the life-cycle. Depletion of snap-29 by RNAi in adults results in sterility associated with endomitotic oocytes and pre-meiotic maturation of the oocytes. Many of the embryos that are produced are multinucleated, indicating a defect in embryonic cytokinesis. A profound defect in secretion by oocytes and early embryos in animals lacking SNAP-29 appears to be the underlying defect connecting these phenotypes. Further analysis revealed defects in basolateral and apical secretion by intestinal epithelial cells in animals lacking SNAP-29, indicating a broad requirement for this protein in the secretory pathway. A SNAP-29-GFP fusion protein was enriched on recycling endosomes, and loss of SNAP-29 disrupted recycling endosome morphology. Taken together these results suggest a requirement for SNAP-29 in the fusion of post-Golgi vesicles with the recycling endosome for cargo to reach the cell surface. PMID:21545795

  16. Caenorhabditis elegans glutamylating enzymes function redundantly in male mating

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    Daniel G. Chawla

    2016-09-01

    Full Text Available Microtubule glutamylation is an important modulator of microtubule function and has been implicated in the regulation of centriole stability, neuronal outgrowth and cilia motility. Glutamylation of the microtubules is catalyzed by a family of tubulin tyrosine ligase-like (TTLL enzymes. Analysis of individual TTLL enzymes has led to an understanding of their specific functions, but how activities of the TTLL enzymes are coordinated to spatially and temporally regulate glutamylation remains relatively unexplored. We have undertaken an analysis of the glutamylating TTLL enzymes in C. elegans. We find that although all five TTLL enzymes are expressed in the embryo and adult worm, loss of individual enzymes does not perturb microtubule function in embryonic cell divisions. Moreover, normal dye-filling, osmotic avoidance and male mating behavior indicate the presence of functional amphid cilia and male-specific neurons. A ttll-4(tm3310; ttll-11(tm4059; ttll-5(tm3360 triple mutant, however, shows reduced male mating efficiency due to a defect in the response step, suggesting that these three enzymes function redundantly, and that glutamylation is required for proper function of the male-specific neurons.

  17. More Sex-Determination Mutants of CAENORHABDITIS ELEGANS

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    Hodgkin, Jonathan

    1980-01-01

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

  18. Metabolic rate regulates L1 longevity in C. elegans.

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    Inhwan Lee

    Full Text Available Animals have to cope with starvation. The molecular mechanisms by which animals survive long-term starvation, however, are not clearly understood. When they hatch without food, C. elegans arrests development at the first larval stage (L1 and survives more than two weeks. Here we show that the survival span of arrested L1s, which we call L1 longevity, is a starvation response regulated by metabolic rate during starvation. A high rate of metabolism shortens the L1 survival span, whereas a low rate of metabolism lengthens it. The longer worms are starved, the slower they grow once they are fed, suggesting that L1 arrest has metabolic costs. Furthermore, mutants of genes that regulate metabolism show altered L1 longevity. Among them, we found that AMP-dependent protein kinase (AMPK, as a key energy sensor, regulates L1 longevity by regulating this metabolic arrest. Our results suggest that L1 longevity is determined by metabolic rate and that AMPK as a master regulator of metabolism controls this arrest so that the animals survive long-term starvation.

  19. Dopamine negatively modulates the NCA ion channels in C. elegans.

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    Topalidou, Irini; Cooper, Kirsten; Pereira, Laura; Ailion, Michael

    2017-10-01

    The NALCN/NCA ion channel is a cation channel related to voltage-gated sodium and calcium channels. NALCN has been reported to be a sodium leak channel with a conserved role in establishing neuronal resting membrane potential, but its precise cellular role and regulation are unclear. The Caenorhabditis elegans orthologs of NALCN, NCA-1 and NCA-2, act in premotor interneurons to regulate motor circuit activity that sustains locomotion. Recently we found that NCA-1 and NCA-2 are activated by a signal transduction pathway acting downstream of the heterotrimeric G protein Gq and the small GTPase Rho. Through a forward genetic screen, here we identify the GPCR kinase GRK-2 as a new player affecting signaling through the Gq-Rho-NCA pathway. Using structure-function analysis, we find that the GPCR phosphorylation and membrane association domains of GRK-2 are required for its function. Genetic epistasis experiments suggest that GRK-2 acts on the D2-like dopamine receptor DOP-3 to inhibit Go signaling and positively modulate NCA-1 and NCA-2 activity. Through cell-specific rescuing experiments, we find that GRK-2 and DOP-3 act in premotor interneurons to modulate NCA channel function. Finally, we demonstrate that dopamine, through DOP-3, negatively regulates NCA activity. Thus, this study identifies a pathway by which dopamine modulates the activity of the NCA channels.

  20. Biotransformation of vinclozolin by the fungus Cunninghamella elegans.

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    Pothuluri, J V; Freeman, J P; Heinze, T M; Beger, R D; Cerniglia, C E

    2000-12-01

    This study investigated the biotransformation of the dicarboximide fungicide vinclozolin [3-(3,5-dichlorophenyl)-5-methyl-5-vinyl-1,3-oxazolidine-2,4-dione] by the fungus Cunninghamella elegans. Experiments with phenyl-[U-ring-14C]vinclozolin showed that after 96 h incubation, 93% had been transformed to four major metabolites. Metabolites were separated by HPLC and characterized by mass and NMR spectroscopy. Biotransformation occurred predominantly on the oxazolidine-2,4-dione portion of vinclozolin. The metabolites were identified as the 3R- and 3S- isomers of 3',5'-dichloro-2,3,4-trihydroxy-2-methylbutyranilide, N-(2-hydroxy-2-methyl-1-oxobuten-3-yl)-3,5-dichlorophenyl-1-carbamic acid, and 3',5'-dichloro-2-hydroxy-2-methylbut-3-enanilide. The enanilide compound has been reported previously as a plant and mammalian metabolite and is implicated to contain antiandrogenic activity. The 3R- and 3S- isomers of 3',5'-dichloro-2,3,4-trihydroxy-2-methylbutyranilide are novel metabolites.

  1. Biotransformation of drospirenone, a contraceptive drug, with Cunninghamella elegans.

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    Baydoun, Elias; Atia-Tul-Wahab; Iqbal, Sheeza; Smith, Colin; Choudhary, M Iqbal

    2017-10-01

    Biotransformation of an orally active contraceptive drug, drospirenone (1), by Cunninghamella elegans ATCC 36114 yielded four new metabolites, 6β,7β,15β,16β-dimethylene-3-oxo-14α-hydroxy-17α-pregn-4-ene-21,17-carbolactone (2), 6β,7β,15β,16β-dimethylene-3,11-dioxo-17α-pregn-4-ene-21,17-carbolactone (3), 6β,7β,15β,16β-dimethylene-3,12-dioxo-17α-pregn-4-ene-21,17-carbolactone (4), and 6β,7β,15β,16β-dimethylene-3-oxo-11β,14α-dihydroxy-17α-pregn-4-ene-21,17-carbolactone (5), along with a known metabolite, 6β,7β,15β,16β-dimethylene-3-oxo-11α-dihydroxy-17α-pregn-4-ene-21,17-carbolactone (6). This study provides not only new analogues of orally active contraceptive drug, drospirenone, but also help in understanding the metabolism of this important drug. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. 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.

  3. 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.

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

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    Demoinet, Emilie; Li, Shaolin; Roy, Richard

    2017-01-01

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

  5. Arbutin increases Caenorhabditis elegans longevity and stress resistance

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    Lin Zhou

    2017-12-01

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

  6. Characterization of the astacin family of metalloproteases in C. elegans

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    Zapf Richard

    2010-01-01

    Full Text Available Abstract Background Astacins are a large family of zinc metalloproteases found in bacteria and animals. They have diverse roles ranging from digestion of food to processing of extracellular matrix components. The C. elegans genome contains an unusually large number of astacins, of which the majority have not been functionally characterized yet. Results We analyzed the expression pattern of previously uncharacterized members of the astacin family to try and obtain clues to potential functions. Prominent sites of expression for many members of this family are the hypodermis, the alimentary system and several specialized cells including sensory sheath and sockets cells, which are located at openings in the body wall. We isolated mutants affecting representative members of the various subfamilies. Mutants in nas-5, nas-21 and nas-39 (the BMP-1/Tolloid homologue are viable and have no apparent phenotypic defects. Mutants in nas-6 and nas-6; nas-7 double mutants are slow growing and have defects in the grinder of the pharynx, a cuticular structure important for food processing. Conclusions Expression data and phenotypic characterization of selected family members suggest a diversity of functions for members of the astacin family in nematodes. In part this might be due to extracellular structures unique to nematodes.

  7. Antibody staining in C. elegans using "freeze-cracking".

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    Duerr, Janet S

    2013-10-14

    To stain C. elegans with antibodies, the relatively impermeable cuticle must be bypassed by chemical or mechanical methods. "Freeze-cracking" is one method used to physically pull the cuticle from nematodes by compressing nematodes between two adherent slides, freezing them, and pulling the slides apart. Freeze-cracking provides a simple and rapid way to gain access to the tissues without chemical treatment and can be used with a variety of fixatives. However, it leads to the loss of many of the specimens and the required compression mechanically distorts the sample. Practice is required to maximize recovery of samples with good morphology. Freeze-cracking can be optimized for specific fixation conditions, recovery of samples, or low non-specific staining, but not for all parameters at once. For antibodies that require very hard fixation conditions and tolerate the chemical treatments needed to chemically permeabilize the cuticle, treatment of intact nematodes in solution may be preferred. If the antibody requires a lighter fix or if the optimum fixation conditions are unknown, freeze-cracking provides a very useful way to rapidly assay the antibody and can yield specific subcellular and cellular localization information for the antigen of interest.

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

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

    2017-05-16

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

  9. A metabolic signature of long life in Caenorhabditis elegans

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    Viney Jonathan M

    2010-02-01

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

  10. 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.

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

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

    2016-06-29

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

  12. 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.

  13. Fourier transform infrared microspectroscopy for the analysis of the biochemical composition of C. elegans worms.

    Science.gov (United States)

    Sheng, Ming; Gorzsás, András; Tuck, Simon

    2016-01-01

    Changes in intermediary metabolism have profound effects on many aspects of C. elegans biology including growth, development and behavior. However, many traditional biochemical techniques for analyzing chemical composition require relatively large amounts of starting material precluding the analysis of mutants that cannot be grown in large amounts as homozygotes. Here we describe a technique for detecting changes in the chemical compositions of C. elegans worms by Fourier transform infrared microspectroscopy. We demonstrate that the technique can be used to detect changes in the relative levels of carbohydrates, proteins and lipids in one and the same worm. We suggest that Fourier transform infrared microspectroscopy represents a useful addition to the arsenal of techniques for metabolic studies of C. elegans worms.

  14. 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

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

    Science.gov (United States)

    Nechipurenko, Inna V; Sengupta, Piali

    2017-01-01

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

  16. 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...

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Eric A Miska

    2007-12-01

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

  19. 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.

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

    Science.gov (United States)

    Prasad, Kedar N; Bondy, Stephen C

    2013-12-01

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

  1. Biodegradation of bisphenol A and its halogenated analogues by Cunninghamella elegans ATCC36112.

    Science.gov (United States)

    Keum, Young Soo; Lee, Hye Ri; Park, Hee Won; Kim, Jeong-Han

    2010-11-01

    Bisphenol A and its halogenated analogues are commonly used industrial chemicals with strong toxicological effects over many organisms. In this study, metabolic fate of bisphenol A and its halogenated analogues were evaluated with Cunninghamella elegans ATCC36112. Bisphenol A and related analogues were rapidly transformed into several metabolites by C. elegans within 2-4 days. Detailed analysis of metabolites reveals that both phase I and II metabolism occurred in C. elegans. Cytochrome P450-dependent hydroxylation was observed in BPA. However, major reaction with bisphenol A and analogues with 1-2 halogen atoms were the formation of glucose-conjugate, not being inhibited by cytochrome P450 inhibitor. Overall metabolic rates decreased with increasing number of substitution at 2- and 6-position of BPA structures, which may be consequences of limited bioavailability or steric hindrance to conjugate-forming reaction. Information from the current study will provide detailed insights over the fungal metabolism of BPA and analogues.

  2. A Collagenolytic Fungus, Cunninghamella elegans, for Biological Control of Plant-parasitic Nematodes

    Science.gov (United States)

    Galper, S.; Cohn, E.; Spiegel, Y.; Chet, I.

    1991-01-01

    The root-galling index of tomatoes inoculated with Meloidogyne javanica was decreased 70% when collagen was used as a soil amendment (0.1% w/w) and 90% when the amendment was supplemented with the collagenolytic fungus Cunninghamella elegans. The root-galling index was reduced 80% when the fungus was homogenized in collagen culture medium and added to soil without collagen supplement. Culture filtrates of the fungus C. elegans, grown on collagen as a single source of carbon and nitrogen, immobilized M. javanica second-stage juveniles and inhibited egg hatch. Root galling was reduced when tomato plants were inoculated with filtrate-treated juveniles. Culture filtrates reduced the motility of Rotylenchulus reniformis and Xiphinema index, but they had less effect on Anguina tritici and almost no effect on Ditylenchus dipsaci. Cunninghamella elegans had collagenolytic, elastolytic, keratinolytic, and nonspecific proteolytic activities when grown on collagen media, but only chitinolytic activity when grown on chitin media. PMID:19283126

  3. Quinoline biodegradation by filamentous fungus Cunninghamella elegans and adaptive modifications of the fungal membrane composition.

    Science.gov (United States)

    Felczak, Aleksandra; Bernat, Przemysław; Różalska, Sylwia; Lisowska, Katarzyna

    2016-05-01

    Quinoline, which belongs to N-heterocyclic compounds, occurs naturally in the environment and is used in numerous industrial processes. The structures of various chemicals, such as dyes and medicines, are based on this compound. Due to that fact, quinoline and its derivatives are widely distributed in environment and can exert toxic effects on organisms from different trophic levels. The ability of the filamentous fungus Cunninghamella elegans IM 1785/21Gp to degrade quinoline and modulate the membrane composition in response to the pollutant was studied. C. elegans IM 1785/21Gp removes quinoline with high efficiency and transforms the pollutant into two novel hydroxylated derivatives, 2-hydroxyquinoline and 3-hydroxyquinoline. Moreover, due to the disruption in the membrane stability by quinoline, C. elegans IM 1785/21Gp modulates the fatty acid composition and phospholipid profile.

  4. 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.

  5. microRNA regulation of the embryonic hypoxic response in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Kagias, Konstantinos; Pocock, Roger

    2015-01-01

    Layered strategies to combat hypoxia provide flexibility in dynamic oxygen environments. Here we show that multiple miRNAs are required for hypoxic survival responses during C. elegans embryogenesis. Certain miRNAs promote while others antagonize the hypoxic survival response. We found that expre......Layered strategies to combat hypoxia provide flexibility in dynamic oxygen environments. Here we show that multiple miRNAs are required for hypoxic survival responses during C. elegans embryogenesis. Certain miRNAs promote while others antagonize the hypoxic survival response. We found...... of the full mRNA target repertoire of these miRNAs will reveal the miRNA-regulated network of hypoxic survival mechanisms in C. elegans....

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  7. 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.

  8. 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

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

  10. Creating defined gaseous environments to study the effects of hypoxia on C. elegans.

    Science.gov (United States)

    Fawcett, Emily M; Horsman, Joseph W; Miller, Dana L

    2012-07-20

    Oxygen is essential for all metazoans to survive, with one known exception. Decreased O(2) availability (hypoxia) can arise during states of disease, normal development or changes in environmental conditions. Understanding the cellular signaling pathways that are involved in the response to hypoxia could provide new insight into treatment strategies for diverse human pathologies, from stroke to cancer. This goal has been impeded, at least in part, by technical difficulties associated with controlled hypoxic exposure in genetically amenable model organisms. The nematode Caenorhabditis elegans is ideally suited as a model organism for the study of hypoxic response, as it is easy to culture and genetically manipulate. Moreover, it is possible to study cellular responses to specific hypoxic O(2) concentrations without confounding effects since C. elegans obtain O(2) (and other gasses) by diffusion, as opposed to a facilitated respiratory system. Factors known to be involved in the response to hypoxia are conserved in C. elegans. The actual response to hypoxia depends on the specific concentration of O(2) that is available. In C. elegans, exposure to moderate hypoxia elicits a transcriptional response mediated largely by hif-1, the highly-conserved hypoxia-inducible transcription factor. C .elegans embryos require hif-1 to survive in 5,000-20,000 ppm O(2). Hypoxia is a general term for "less than normal O(2)". Normoxia (normal O(2)) can also be difficult to define. We generally consider room air, which is 210,000 ppm O(2) to be normoxia. However, it has been shown that C. elegans has a behavioral preference for O(2) concentrations from 5-12% (50,000-120,000 ppm O(2)). In larvae and adults, hif-1 acts to prevent hypoxia-induced diapause in 5,000 ppm O(2). However, hif-1 does not play a role in the response to lower concentrations of O(2) (anoxia, operational definition gasses.

  11. Beyond Traditional Antimicrobials: A Caenorhabditis elegans Model for Discovery of Novel Anti-infectives

    Science.gov (United States)

    Kong, Cin; Eng, Su-Anne; Lim, Mei-Perng; Nathan, Sheila

    2016-01-01

    The spread of antibiotic resistance amongst bacterial pathogens has led to an urgent need for new antimicrobial compounds with novel modes of action that minimize the potential for drug resistance. To date, the development of new antimicrobial drugs is still lagging far behind the rising demand, partly owing to the absence of an effective screening platform. Over the last decade, the nematode Caenorhabditis elegans has been incorporated as a whole animal screening platform for antimicrobials. This development is taking advantage of the vast knowledge on worm physiology and how it interacts with bacterial and fungal pathogens. In addition to allowing for in vivo selection of compounds with promising anti-microbial properties, the whole animal C. elegans screening system has also permitted the discovery of novel compounds targeting infection processes that only manifest during the course of pathogen infection of the host. Another advantage of using C. elegans in the search for new antimicrobials is that the worm itself is a source of potential antimicrobial effectors which constitute part of its immune defense response to thwart infections. This has led to the evaluation of effector molecules, particularly antimicrobial proteins and peptides (APPs), as candidates for further development as therapeutic agents. In this review, we provide an overview on use of the C. elegans model for identification of novel anti-infectives. We highlight some highly potential lead compounds obtained from C. elegans-based screens, particularly those that target bacterial virulence or host defense to eradicate infections, a mechanism distinct from the action of conventional antibiotics. We also review the prospect of using C. elegans APPs as an antimicrobial strategy to treat infections. PMID:27994583

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

    Directory of Open Access Journals (Sweden)

    Shane L Rea

    2007-10-01

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

  13. Heterologous Expression in Remodeled C. elegans: A Platform for Monoaminergic Agonist Identification and Anthelmintic Screening.

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2007-02-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Inhibition of HMG-CoA reductase induces the UPR pathway in C. elegans

    DEFF Research Database (Denmark)

    Olsen, Louise Cathrine Braun; Hansen, Nadia Jin Storm; Pilon, Marc

    -requiring enzyme-1 (IRE-1), and activating transcription factor-6 (ATF-6). Using a transgenic GFP reporter strain of the model organism C. elegans, we have recently identified that inhibition of the enzyme HMG-CoA reductase (HMG-CoAR) with Fluvastatin and knock down of HMG-CoAR using RNA interference (RNAi) both...... including farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) which are necessary for posttranslational prenylation of several small G proteins. C. elegans are cholesterol auxotrophs, which enable us to investigate the isoprenoid branch and its role in UPR induction. We found...

  18. Serotonin regulates C. elegans fat and feeding through independent molecular mechanisms

    DEFF Research Database (Denmark)

    Srinivasan, Supriya; Sadegh, Leila; Elle, Ida C

    2008-01-01

    We investigated serotonin signaling in C. elegans as a paradigm for neural regulation of energy balance and found that serotonergic regulation of fat is molecularly distinct from feeding regulation. Serotonergic feeding regulation is mediated by receptors whose functions are not required for fat...... feeding behavior. These findings suggest that, as in mammals, C. elegans feeding behavior is regulated by extrinsic and intrinsic cues. Moreover, obesity and thinness are not solely determined by feeding behavior. Rather, feeding behavior and fat metabolism are coordinated but independent responses...

  19. High-throughput screening for novel anti-infectives using a C. elegans pathogenesis model.

    Science.gov (United States)

    Conery, Annie L; Larkins-Ford, Jonah; Ausubel, Frederick M; Kirienko, Natalia V

    2014-03-14

    In recent history, the nematode Caenorhabditis elegans has provided a compelling platform for the discovery of novel antimicrobial drugs. In this protocol, we present an automated, high-throughput C. elegans pathogenesis assay, which can be used to screen for anti-infective compounds that prevent nematodes from dying due to Pseudomonas aeruginosa. New antibiotics identified from such screens would be promising candidates for treatment of human infections, and also can be used as probe compounds to identify novel targets in microbial pathogenesis or host immunity. Copyright © 2014 John Wiley & Sons, Inc.

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

    OpenAIRE

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

    2002-01-01

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

  1. Identification of a novel metabolite in phenanthrene metabolism by the fungus Cunninghamella elegans.

    Science.gov (United States)

    Cerniglia, C E; Campbell, W L; Freeman, J P; Evans, F E

    1989-01-01

    The metabolism of phenanthrene by the fungus Cunninghamella elegans was investigated. Kinetic experiments using [9-14C]phenanthrene showed that after 72 h, 53% of the total radioactivity was associated with a glucoside conjugate of 1-hydroxyphenanthrene (phenanthrene 1-O-beta-glucose). This metabolite was isolated by reversed-phase high-performance liquid chromatography and characterized by the application of UV absorption, 1H nuclear magnetic resonance, and mass spectral techniques. The results show that aromatic ring oxidation followed by glucosylation is a predominant pathway in the metabolism of the polycyclic aromatic hydrocarbon phenanthrene by C. elegans. PMID:2802607

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  3. Proteomic profiling during the pre-competent to competent transition of the biofouling polychaete Hydroides elegans

    KAUST Repository

    Zhang, Yu

    2014-08-22

    The polychaete, Hydroides elegans, is a tube-building worm that is widely distributed in tropical and subtropical seas. It is a dominant fouling species and thus a major target organism in antifouling research. Here, the first high-throughput proteomic profiling of pre-competent and competent larvae of H. elegans is reported with the identification of 1,519 and 1,322 proteins, respectively. These proteins were associated with a variety of biological processes. However, a large proportion was involved in energy metabolism, redox homeostasis, and microtubule-based processes. A comparative analysis revealed 21 proteins that were differentially regulated in larvae approaching competency.

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

    Science.gov (United States)

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

    2013-01-01

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

  5. Predictive modeling of signaling crosstalk during C. elegans vulval development.

    Directory of Open Access Journals (Sweden)

    Jasmin Fisher

    2007-05-01

    Full Text Available Caenorhabditis elegans vulval development provides an important paradigm for studying the process of cell fate determination and pattern formation during animal development. Although many genes controlling vulval cell fate specification have been identified, how they orchestrate themselves to generate a robust and invariant pattern of cell fates is not yet completely understood. Here, we have developed a dynamic computational model incorporating the current mechanistic understanding of gene interactions during this patterning process. A key feature of our model is the inclusion of multiple modes of crosstalk between the epidermal growth factor receptor (EGFR and LIN-12/Notch signaling pathways, which together determine the fates of the six vulval precursor cells (VPCs. Computational analysis, using the model-checking technique, provides new biological insights into the regulatory network governing VPC fate specification and predicts novel negative feedback loops. In addition, our analysis shows that most mutations affecting vulval development lead to stable fate patterns in spite of variations in synchronicity between VPCs. Computational searches for the basis of this robustness show that a sequential activation of the EGFR-mediated inductive signaling and LIN-12 / Notch-mediated lateral signaling pathways is key to achieve a stable cell fate pattern. We demonstrate experimentally a time-delay between the activation of the inductive and lateral signaling pathways in wild-type animals and the loss of sequential signaling in mutants showing unstable fate patterns; thus, validating two key predictions provided by our modeling work. The insights gained by our modeling study further substantiate the usefulness of executing and analyzing mechanistic models to investigate complex biological behaviors.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Raj Kumar Pan

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

  8. The oogenic germline starvation response in C. elegans.

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    Hannah S Seidel

    Full Text Available Many animals alter their reproductive strategies in response to environmental stress. Here we have investigated how L4 hermaphrodites of Caenorhabditis elegans respond to starvation. To induce starvation, we removed food at 2 h intervals from very early- to very late-stage L4 animals. The starved L4s molted into adulthood, initiated oogenesis, and began producing embryos; however, all three processes were severely delayed, and embryo viability was reduced. Most animals died via 'bagging,' because egg-laying was inhibited, and embryos hatched in utero, consuming their parent hermaphrodites from within. Some animals, however, avoided bagging and survived long term. Long-term survival did not rely on embryonic arrest but instead upon the failure of some animals to produce viable progeny during starvation. Regardless of the bagging fate, starved animals showed two major changes in germline morphology: All oogenic germlines were dramatically reduced in size, and these germlines formed only a single oocyte at a time, separated from the remainder of the germline by a tight constriction. Both changes in germline morphology were reversible: Upon re-feeding, the shrunken germlines regenerated, and multiple oocytes formed concurrently. The capacity for germline regeneration upon re-feeding was not limited to the small subset of animals that normally survive starvation: When bagging was prevented ectopically by par-2 RNAi, virtually all germlines still regenerated. In addition, germline shrinkage strongly correlated with oogenesis, suggesting that during starvation, germline shrinkage may provide material for oocyte production. Finally, germline shrinkage and regeneration did not depend upon crowding. Our study confirms previous findings that starvation uncouples germ cell proliferation from germline stem cell maintenance. Our study also suggests that when nutrients are limited, hermaphrodites scavenge material from their germlines to reproduce. We discuss

  9. MicroRNA predictors of longevity in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Zachary Pincus

    2011-09-01

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

  10. Tertiary siRNAs mediate paramutation in C. elegans.

    Science.gov (United States)

    Sapetschnig, Alexandra; Sarkies, Peter; Lehrbach, Nicolas J; Miska, Eric A

    2015-03-01

    In the nematode Caenorhabditis elegans, different small RNA-dependent gene silencing mechanisms act in the germline to initiate transgenerational gene silencing. Piwi-interacting RNAs (piRNAs) can initiate transposon and gene silencing by acting upstream of endogenous short interfering RNAs (siRNAs), which engage a nuclear RNA interference (RNAi) pathway to trigger transcriptional gene silencing. Once gene silencing has been established, it can be stably maintained over multiple generations without the requirement of the initial trigger and is also referred to as RNAe or paramutation. This heritable silencing depends on the integrity of the nuclear RNAi pathway. However, the exact mechanism by which silencing is maintained across generations is not understood. Here we demonstrate that silencing of piRNA targets involves the production of two distinct classes of small RNAs with different genetic requirements. The first class, secondary siRNAs, are localized close to the direct target site for piRNAs. Nuclear import of the secondary siRNAs by the Argonaute HRDE-1 leads to the production of a distinct class of small RNAs that map throughout the transcript, which we term tertiary siRNAs. Both classes of small RNAs are necessary for full repression of the target gene and can be maintained independently of the initial piRNA trigger. Consistently, we observed a form of paramutation associated with tertiary siRNAs. Once paramutated, a tertiary siRNA generating allele confers dominant silencing in the progeny regardless of its own transmission, suggesting germline-transmitted siRNAs are sufficient for multigenerational silencing. This work uncovers a multi-step siRNA amplification pathway that promotes germline integrity via epigenetic silencing of endogenous and invading genetic elements. In addition, the same pathway can be engaged in environmentally induced heritable gene silencing and could therefore promote the inheritance of acquired traits.

  11. D-beta-hydroxybutyrate extends lifespan in C. elegans.

    Science.gov (United States)

    Edwards, Clare; Canfield, John; Copes, Neil; Rehan, Muhammad; Lipps, David; Bradshaw, Patrick C

    2014-08-01

    The ketone body beta-hydroxybutyrate (βHB) is a histone deacetylase (HDAC) inhibitor and has been shown to be protective in many disease models, but its effects on aging are not well studied. Therefore we determined the effect of βHB supplementation on the lifespan ofC. elegans nematodes. βHB supplementation extended mean lifespan by approximately 20%. RNAi knockdown of HDACs hda-2 or hda-3 also increased lifespan and further prevented βHB-mediated lifespan extension. βHB-mediated lifespan extension required the DAF-16/FOXO and SKN-1/Nrf longevity pathways, the sirtuin SIR-2.1, and the AMP kinase subunit AAK-2. βHB did not extend lifespan in a genetic model of dietary restriction indicating that βHB is likely functioning through a similar mechanism. βHB addition also upregulated ΒHB dehydrogenase activity and increased oxygen consumption in the worms. RNAi knockdown of F55E10.6, a short chain dehydrogenase and SKN-1 target gene, prevented the increased lifespan and βHB dehydrogenase activity induced by βHB addition, suggesting that F55E10.6 functions as an inducible βHB dehydrogenase. Furthermore, βHB supplementation increased worm thermotolerance and partially prevented glucose toxicity. It also delayed Alzheimer's amyloid-beta toxicity and decreased Parkinson's alpha-synuclein aggregation. The results indicate that D-βHB extends lifespan through inhibiting HDACs and through the activation of conserved stress response pathways.

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

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    Timothy Truong

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

  13. Identifying novel genes in C. elegans using SAGE tags

    Directory of Open Access Journals (Sweden)

    Chen Nansheng

    2010-12-01

    Full Text Available Abstract Background Despite extensive efforts devoted to predicting protein-coding genes in genome sequences, many bona fide genes have not been found and many existing gene models are not accurate in all sequenced eukaryote genomes. This situation is partly explained by the fact that gene prediction programs have been developed based on our incomplete understanding of gene feature information such as splicing and promoter characteristics. Additionally, full-length cDNAs of many genes and their isoforms are hard to obtain due to their low level or rare expression. In order to obtain full-length sequences of all protein-coding genes, alternative approaches are required. Results In this project, we have developed a method of reconstructing full-length cDNA sequences based on short expressed sequence tags which is called sequence tag-based amplification of cDNA ends (STACE. Expressed tags are used as anchors for retrieving full-length transcripts in two rounds of PCR amplification. We have demonstrated the application of STACE in reconstructing full-length cDNA sequences using expressed tags mined in an array of serial analysis of gene expression (SAGE of C. elegans cDNA libraries. We have successfully applied STACE to recover sequence information for 12 genes, for two of which we found isoforms. STACE was used to successfully recover full-length cDNA sequences for seven of these genes. Conclusions The STACE method can be used to effectively reconstruct full-length cDNA sequences of genes that are under-represented in cDNA sequencing projects and have been missed by existing gene prediction methods, but their existence has been suggested by short sequence tags such as SAGE tags.

  14. New role for DCR-1/dicer in Caenorhabditis elegans innate immunity against the highly virulent bacterium Bacillus thuringiensis DB27.

    Science.gov (United States)

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

    2013-10-01

    Bacillus thuringiensis produces toxins that target invertebrates, including Caenorhabditis elegans. Virulence of Bacillus strains is often highly specific, such that B. thuringiensis strain DB27 is highly pathogenic to C. elegans but shows no virulence for another model nematode, Pristionchus pacificus. To uncover the underlying mechanisms of the differential responses of the two nematodes to B. thuringiensis DB27 and to reveal the C. elegans defense mechanisms against this pathogen, we conducted a genetic screen for C. elegans mutants resistant to B. thuringiensis DB27. Here, we describe a B. thuringiensis DB27-resistant C. elegans mutant that is identical to nasp-1, which encodes the C. elegans homolog of the nuclear-autoantigenic-sperm protein. Gene expression analysis indicated a substantial overlap between the genes downregulated in the nasp-1 mutant and targets of C. elegans dcr-1/Dicer, suggesting that dcr-1 is repressed in nasp-1 mutants, which was confirmed by quantitative PCR. Consistent with this, the nasp-1 mutant exhibits RNA interference (RNAi) deficiency and reduced longevity similar to those of a dcr-1 mutant. Building on these surprising findings, we further explored a potential role for dcr-1 in C. elegans innate immunity. We show that dcr-1 mutant alleles deficient in microRNA (miRNA) processing, but not those deficient only in RNAi, are resistant to B. thuringiensis DB27. Furthermore, dcr-1 overexpression rescues the nasp-1 mutant's resistance, suggesting that repression of dcr-1 determines the nasp-1 mutant's resistance. Additionally, we identified the collagen-encoding gene col-92 as one of the downstream effectors of nasp-1 that play an important role in resistance to DB27. Taken together, these results uncover a previously unknown role for DCR-1/Dicer in C. elegans antibacterial immunity that is largely associated with miRNA processing.

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

    Science.gov (United States)

    Iatsenko, Igor; Sinha, Amit; Rödelsperger, Christian

    2013-01-01

    Bacillus thuringiensis produces toxins that target invertebrates, including Caenorhabditis elegans. Virulence of Bacillus strains is often highly specific, such that B. thuringiensis strain DB27 is highly pathogenic to C. elegans but shows no virulence for another model nematode, Pristionchus pacificus. To uncover the underlying mechanisms of the differential responses of the two nematodes to B. thuringiensis DB27 and to reveal the C. elegans defense mechanisms against this pathogen, we conducted a genetic screen for C. elegans mutants resistant to B. thuringiensis DB27. Here, we describe a B. thuringiensis DB27-resistant C. elegans mutant that is identical to nasp-1, which encodes the C. elegans homolog of the nuclear-autoantigenic-sperm protein. Gene expression analysis indicated a substantial overlap between the genes downregulated in the nasp-1 mutant and targets of C. elegans dcr-1/Dicer, suggesting that dcr-1 is repressed in nasp-1 mutants, which was confirmed by quantitative PCR. Consistent with this, the nasp-1 mutant exhibits RNA interference (RNAi) deficiency and reduced longevity similar to those of a dcr-1 mutant. Building on these surprising findings, we further explored a potential role for dcr-1 in C. elegans innate immunity. We show that dcr-1 mutant alleles deficient in microRNA (miRNA) processing, but not those deficient only in RNAi, are resistant to B. thuringiensis DB27. Furthermore, dcr-1 overexpression rescues the nasp-1 mutant's resistance, suggesting that repression of dcr-1 determines the nasp-1 mutant's resistance. Additionally, we identified the collagen-encoding gene col-92 as one of the downstream effectors of nasp-1 that play an important role in resistance to DB27. Taken together, these results uncover a previously unknown role for DCR-1/Dicer in C. elegans antibacterial immunity that is largely associated with miRNA processing. PMID:23918784

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

    Science.gov (United States)

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

    2017-02-06

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

  17. Genomic analysis of immune response against Vibrio cholerae hemolysin in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Surasri N Sahu

    Full Text Available Vibrio cholerae cytolysin (VCC is among the accessory V. cholerae virulence factors that may contribute to disease pathogenesis in humans. VCC, encoded by hlyA gene, belongs to the most common class of bacterial toxins, known as pore-forming toxins (PFTs. V. cholerae infects and kills Caenorhabditis elegans via cholerae toxin independent manner. VCC is required for the lethality, growth retardation and intestinal cell vacuolation during the infection. However, little is known about the host gene expression responses against VCC. To address this question we performed a microarray study in C. elegans exposed to V. cholerae strains with intact and deleted hlyA genes.Many of the VCC regulated genes identified, including C-type lectins, Prion-like (glutamine [Q]/asparagine [N]-rich-domain containing genes, genes regulated by insulin/IGF-1-mediated signaling (IIS pathway, were previously reported as mediators of innate immune response against other bacteria in C. elegans. Protective function of the subset of the genes up-regulated by VCC was confirmed using RNAi. By means of a machine learning algorithm called FastMEDUSA, we identified several putative VCC induced immune regulatory transcriptional factors and transcription factor binding motifs. Our results suggest that VCC is a major virulence factor, which induces a wide variety of immune response- related genes during V. cholerae infection in C. elegans.

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

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    Bhagavathi Sundaram Sivamaruthi

    2012-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Katie Nicoll Baines

    2017-05-01

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

  20. Tracking C. elegans and its neuromuscular activity using NemaFlex

    Science.gov (United States)

    van Bussel, Frank; Rahman, Mizanur; Hewitt, Jennifer; Blawzdziewicz, Jerzy; Driscoll, Monica; Szewczyk, Nathaniel; Vanapalli, Siva

    Recently, a novel platform has been developed for studying the behavior and physical characteristics of the nematode C. elegans. This is NemaFlex, developed by the Vanapalli group at Texas Tech University to analyze movement and muscular strength of crawling C. elegans. NemaFlex is a microfluidic device consisting of an array of deformable PDMS pillars, with which the C. elegans interacts in the course of moving through the system. Deflection measurements then allow us to calculate the force exerted by the worm via Euler-Bernoulli beam theory. For the procedure to be fully automated a fairly sophisticated software analysis has to be developed in tandem with the physical device. In particular, the usefulness of the force calculations is highly dependent on the accuracy and volume of the deflection measurements, which would be prohibitively time-consuming if carried out by hand/eye. In order to correlate the force results with muscle activations the C. elegans itself has to be tracked simultaneously, and pillar deflections precisely associated with mechanical-contact on the worm's body. Here we will outline the data processing and analysis routines that have been implemented in order to automate the calculation of these forces and muscular activations.

  1. Toxicity of simple mixtures to the nematode Caenhorhabditis elegans in relation to soil sorption

    NARCIS (Netherlands)

    Jonker, M.J.; Sweijen, R.A.J.C.; Kammenga, J.E.

    2004-01-01

    Single and combined toxicity of copper-zinc, copper-cadmium, cadmium-lead, copper-carbendazim, and copper-carbendazimiprodione to the nematode Caenorhabditis elegans in soil was studied. The one-week population increase was estimated as the toxicity endpoint. The aim was to study the relationship

  2. Identification of lipid droplet structure-like/resident proteins in Caenorhabditis elegans.

    Science.gov (United States)

    Na, Huimin; Zhang, Peng; Chen, Yong; Zhu, Xiaotong; Liu, Yi; Liu, Yangli; Xie, Kang; Xu, Ningyi; Yang, Fuquan; Yu, Yong; Cichello, Simon; Mak, Ho Yi; Wang, Meng C; Zhang, Hong; Liu, Pingsheng

    2015-10-01

    The lipid droplet (LD) is a cellular organelle that stores neutral lipids in cells and has been linked with metabolic disorders. Caenorhabditis elegans has many characteristics which make it an excellent animal model for studying LDs. However, unlike in mammalian cells, no LD structure-like/resident proteins have been identified in C. elegans, which has limited the utility of this model for the study of lipid storage and metabolism. Herein based on three lines of evidence, we identified that MDT-28 and DHS-3 previously identified in C. elegans LD proteome were two LD structure-like/resident proteins. First, MDT-28 and DHS-3 were found to be the two most abundant LD proteins in the worm. Second, the proteins were specifically localized to LDs and we identified the domains responsible for this targeting in both proteins. Third and most importantly, the depletion of MDT-28 induced LD clustering while DHS-3 deletion reduced triacylglycerol content (TAG). We further characterized the proteins finding that MDT-28 was ubiquitously expressed in the intestine, muscle, hypodermis, and embryos, whereas DHS-3 was expressed mainly in intestinal cells. Together, these two LD structure-like/resident proteins provide a basis for future mechanistic studies into the dynamics and functions of LDs in C. elegans. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2014-07-02

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

  4. EGF Signal Propagation during C. elegans Vulval Development Mediated by ROM-1 Rhomboid: e334

    National Research Council Canada - National Science Library

    Amit Dutt; Stefano Canevascini; Erika Froehli-Hoier; Alex Hajnal

    2004-01-01

    ...). The inductive AC signal specifies the vulval fates of the three proximal VPCs P5.p, P6.p, and P7.p. The C. elegans Rhomboid homolog ROM-1 increases the range of EGF, allowing the inductive signal to reach the distal VPCs P3...

  5. EGF signal propagation during C. elegans vulval development mediated by ROM-1 rhomboid

    National Research Council Canada - National Science Library

    Dutt, Amit; Canevascini, Stefano; Froehli-Hoier, Erika; Hajnal, Alex

    2004-01-01

    ...). The inductive AC signal specifies the vulval fates of the three proximal VPCs P5.p, P6.p, and P7.p. The C. elegans Rhomboid homolog ROM-1 increases the range of EGF, allowing the inductive signal to reach the distal VPCs P3...

  6. Efficient target-selected mutagenesis in Caenorhabditis elegans : toward a knockout for every gene

    NARCIS (Netherlands)

    Cuppen, Edwin; Gort, Eelke; Hazendonk, Esther; Mudde, Josine; van de Belt, José; Nijman, Isaäc J; Guryev, Victor; Plasterk, Ronald H A

    Reverse genetic or gene-driven knockout approaches have contributed significantly to the success of model organisms for fundamental and biomedical research. Although various technologies are available for C. elegans, none of them scale very well for genome-wide application. To address this, we

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

    NARCIS (Netherlands)

    J.A. Burghoorn (Jan)

    2006-01-01

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

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

    Science.gov (United States)

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

    2011-07-01

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

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

    NARCIS (Netherlands)

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

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

  10. Antimicrobial effectors in the nematode Caenorhabditis elegans: an outgroup to the Arthropoda.

    Science.gov (United States)

    Dierking, Katja; Yang, Wentao; Schulenburg, Hinrich

    2016-05-26

    Nematodes and arthropods likely form the taxon Ecdysozoa. Information on antimicrobial effectors from the model nematode Caenorhabditis elegans may thus shed light on the evolutionary origin of these defences in arthropods. This nematode species possesses an extensive armory of putative antimicrobial effector proteins, such as lysozymes, caenopores (or saposin-like proteins), defensin-like peptides, caenacins and neuropeptide-like proteins, in addition to the production of reactive oxygen species and autophagy. As C. elegans is a bacterivore that lives in microbe-rich environments, some of its effector peptides and proteins likely function in both digestion of bacterial food and pathogen elimination. In this review, we provide an overview of C. elegans immune effector proteins and mechanisms. We summarize the experimental evidence of their antimicrobial function and involvement in the response to pathogen infection. We further evaluate the microbe-induced expression of effector genes using WormExp, a recently established database for C. elegans gene expression analysis. We emphasize the need for further analysis at the protein level to demonstrate an antimicrobial activity of these molecules both in vitro and in vivoThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Author(s).

  11. Growth and nutrition of two cultivars of zinnia elegans under saline conditions

    Science.gov (United States)

    Zinnia elegans, because of its economic value and the hardiness of its wild relatives, was selected for its potential as a salt-tolerant cut flower crop to grow in greenhouse systems using recycled agricultural wastewater. Using recycled wastewater for irrigation of cut flowers provides an alternat...

  12. Catalytic-independent roles of UTX-1 in C. elegans development

    DEFF Research Database (Denmark)

    Vandamme, Julien; Salcini, Anna Elisabetta

    2013-01-01

    We recently analyzed the functional roles of UTX-1 during development. utx-1 is an essential gene required for the correct embryonic and post-embryonic development of C. elegans, and it displays an H3K27me3 demethylase activity. Rescue experiments demonstrated that the enzymatic activity of UTX-1...

  13. Alternative polymerases in the maintenance of genome stability in C. elegans

    NARCIS (Netherlands)

    Roerink, Sophie Frederique

    2014-01-01

    In this thesis I describe the developmental role of the Y-family polymerases Pol Eta, Pol Kappa and Rev1 in protection against exogenous and endogenous damage in C. elegans. Furthermore I identify a new role for the A-family Polymerase Pol Theta in repair of replication-associated breaks.

  14. Long-Term High-Resolution Imaging of Developing C. elegans Larvae with Microfluidics.

    Science.gov (United States)

    Keil, Wolfgang; Kutscher, Lena M; Shaham, Shai; Siggia, Eric D

    2017-01-23

    Long-term studies of Caenorhabditis elegans larval development traditionally require tedious manual observations because larvae must move to develop, and existing immobilization techniques either perturb development or are unsuited for young larvae. Here, we present a simple microfluidic device to simultaneously follow development of ten C. elegans larvae at high spatiotemporal resolution from hatching to adulthood (∼3 days). Animals grown in microchambers are periodically immobilized by compression to allow high-quality imaging of even weak fluorescence signals. Using the device, we obtain cell-cycle statistics for C. elegans vulval development, a paradigm for organogenesis. We combine Nomarski and multichannel fluorescence microscopy to study processes such as cell-fate specification, cell death, and transdifferentiation throughout post-embryonic development. Finally, we generate time-lapse movies of complex neural arborization through automated image registration. Our technique opens the door to quantitative analysis of time-dependent phenomena governing cellular behavior during C. elegans larval development. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Serotonin Mediates a Learned Increase in Attraction to High Concentrations of Benzaldehyde in Aged "C. elegans"

    Science.gov (United States)

    Tsui, David; van der Kooy, Derek

    2008-01-01

    We utilized olfactory-mediated chemotaxis in "Caenorhabditis elegans" to examine the effect of aging on information processing and animal behavior. Wild-type (N2) young adults (day 4) initially approach and eventually avoid a point source of benzaldehyde. Aged adult animals (day 7) showed a stronger initial approach and a delayed avoidance to…

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

    Directory of Open Access Journals (Sweden)

    Selma Waaijers

    2015-02-01

    Full Text Available 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 sequence to mammalian CRB3. We visualized CRB-3 subcellular localization by expressing a translational GFP fusion. CRB-3::GFP was expressed in several polarized tissues in the embryo and larval stages, and showed apical localization in the intestine and pharynx. To identify the function of the Crumbs family in C. elegans development, we generated a triple Crumbs deletion mutant by sequentially removing the entire coding sequence for each crumbs homolog using a CRISPR/Cas9-based approach. Remarkably, animals lacking all three Crumbs homologs are viable and show normal epithelial polarity. Thus, the three C. elegans Crumbs family members do not appear to play an essential role in epithelial polarity establishment.

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

    Science.gov (United States)

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

    2014-08-01

    Genome editing based on CRISPR (clustered regularly interspaced short palindromic repeats)-associated nuclease (Cas9) has been successfully applied in dozens of diverse plant and animal species, including the nematode Caenorhabditis elegans. The rapid life cycle and easy access to the ovary by micro-injection make C. elegans an ideal organism both for applying CRISPR-Cas9 genome editing technology and for optimizing genome-editing protocols. Here we report efficient and straightforward CRISPR-Cas9 genome-editing methods for C. elegans, including a Co-CRISPR strategy that facilitates detection of genome-editing events. We describe methods for detecting homologous recombination (HR) events, including direct screening methods as well as new selection/counterselection strategies. Our findings reveal a surprisingly high frequency of HR-mediated gene conversion, making it possible to rapidly and precisely edit the C. elegans genome both with and without the use of co-inserted marker genes. Copyright © 2014 by the Genetics Society of America.

  18. Behavioural and genetic evidence for C. elegans' ability to detect volatile chemicals associated with explosives.

    Science.gov (United States)

    Liao, Chunyan; Gock, Andrew; Michie, Michelle; Morton, Bethany; Anderson, Alisha; Trowell, Stephen

    2010-09-07

    Automated standoff detection and classification of explosives based on their characteristic vapours would be highly desirable. Biologically derived odorant receptors have potential as the explosive recognition element in novel biosensors. Caenorhabditis elegans' genome contains over 1,000 uncharacterised candidate chemosensory receptors. It was not known whether any of these respond to volatile chemicals derived from or associated with explosives. We assayed C. elegans for chemotactic responses to chemical vapours of explosives and compounds associated with explosives. C. elegans failed to respond to many of the explosive materials themselves but showed strong chemotaxis with a number of compounds associated with commercial or homemade explosives. Genetic mutant strains were used to identify the likely neuronal location of a putative receptor responding to cyclohexanone, which is a contaminant of some compounded explosives, and to identify the specific transduction pathway involved. Upper limits on the sensitivity of the nematode were calculated. A sensory adaptation protocol was used to estimate the receptive range of the receptor. The results suggest that C. elegans may be a convenient source of highly sensitive, narrowly tuned receptors to detect a range of explosive-associated volatiles.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    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.