These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Fatal Actinomucor elegans var. kuwaitiensis Infection following Combat Trauma?  

PubMed Central

We report the first case of invasive mucormycosis secondary to Actinomucor elegans infection. A severely injured soldier with a fatal A. elegans var. kuwaitiensis infection is described. The identification of this fungus was performed by classical and molecular methods, and this report documents the pathogenicity of the recently described variety Actinomucor elegans var. kuwaitiensis. PMID:19675213

Tully, Charla C.; Romanelli, Anna M.; Sutton, Deanna A.; Wickes, Brian L.; Hospenthal, Duane R.

2009-01-01

2

Enhanced Glucosamine Production with Actinomucor elegans Based on Stimulating Factor of Methanol.  

PubMed

Glucosamine (GlcN) is a major and valuable component in the cell wall of fungi. In this study, the cell wall was treated via a two-stage alkali and acid process, and chitin and chitosan were fully deacetylated, partially depolymerized, and converted to GlcN oligosaccharides. Then, the oligosaccharides were analyzed by high performance liquid chromatography. The influences of Actinomucor elegans on GlcN production in a flask culture were investigated to achieve an optimum yield of GlcN. The experimental result showed that cultivation in condition of pH 6.0, 100 mL working volume (500 mL flask), 10 % (v/v) inoculum concentration, at 28 °C and 200 rpm for 6 days yielded highest dry cell weight (DCW) which was 23.43 g L(-1), with a GlcN concentration of 5.12 g L(-1). Methanol as stimulating factor was found to exert the best effect in concentration of 1.5 % (v/v). With addition of methanol into medium, the DCW increased from 23.69 to 32.42 g L(-1), leading to maximum GlcN concentration of 6.85 g L(-1) obtained. Here, the methanol addition may be useful for industrial production of GlcN, and may also be meaningful for the production of other fine chemicals by filamentous fungi. PMID:25320446

Wang, Sheng; Li, Piwu; Su, Jing; Liang, Rongrong; Wu, Xiangkun

2014-12-01

3

Antioxidant activity and protective effect of Turnera ulmifolia Linn. var. elegans against carbon tetrachloride-induced oxidative damage in rats.  

PubMed

The present study aimed to determine whether the leaves of Turnera ulmifolia Linn. var. elegans extract exert significant antioxidant activity. The antioxidant activity of its hydroethanolic extract (HEETU) was evaluated by assessing (a) its radical scavenging ability in vitro, and (b) its in vivo effect on lipid peroxidation and antioxidant enzyme activities. The in vitro antioxidant assay (DPPH) clearly supported HEETU free radical scavenging potential. Moreover, glutathione content and antioxidant enzyme activities (glutathione peroxidase, superoxide dismutase and catalase) were significantly enhanced in CCl(4)-treated rats due to oral HEETU-treatment (500 mg/kgb.w.) over 7 and 21 days. In addition, an improvement was observed in lipid peroxidation and serum biochemical parameters (aspartate aminotransferase and alanine aminotransferase), indicating a protective effect against CCl(4)-induced liver injuries, confirmed by histopathological studies. The HEETU effect was comparable to the standard drug Legalon® (50 mg/kgb.w.) under the same experimental condition. Quantitative analysis of the HPLC extract revealed the presence of flavonoids, wich mediate the effects of antioxidant and oxidative stress. In conclusion, extract components exhibit antioxidant and hepatoprotective activities in vitro and in vivo. PMID:22940430

Brito, Naira J N; López, Jorge A; do Nascimento, Maria Aparecida; Macêdo, José B M; Silva, Gabriel Araujo; Oliveira, Cláudia N; de Rezende, Adriana Augusto; Brandão-Neto, José; Schwarz, Aline; Almeida, Maria das Graças

2012-12-01

4

Caenorhabditis elegans Radiation Responses  

Microsoft Academic Search

\\u000a Over the past 10 years a number of laboratories have started to focus on Caenorhabditis elegans radiation responses, taking advantage of a multi-cellular experimental model system that enables studying DNA damage responses\\u000a at the organismal level. Here we provide a comprehensive review of C. elegans DNA damage responses, largely focusing on recombinational repair, DNA damage signalling and DNA damage-induced apoptosis

Aymeric Bailly; Anton Gartner

5

Neural Regeneration in Caenorhabditis elegans  

PubMed Central

Axon regeneration is a medically relevant process that can repair damaged neurons. This review describes current progress in understanding axon regeneration in the model organism Caenorhabditis elegans. Factors that regulate axon regeneration in C. elegans have broadly similar roles in vertebrate neurons. This means that using C. elegans as a tool to leverage discovery is a legitimate strategy for identifying conserved mechanisms of axon regeneration. PMID:22974301

El Bejjani, Rachid; Hammarlund, Marc

2013-01-01

6

Toxicity testing using Caenorhabditis elegans  

SciTech Connect

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

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

1995-12-31

7

Aggregation Pheromone of Pityokteines elegans  

Microsoft Academic Search

In laboratory bioassay experiments, the beetles Pityokteines elegans were attracted to volatiles captured from bolts of grand fir, Abies grandis, colonized by P. elegans males. Male-specific volatiles detected by coupled gas chromatographic–electroantennographic detection (GC-EAD) analysis and by GC–mass spectrometry employing a chiral column were: (S)-(-)-ipsenol, (+)- and (-)-ipsdienol, and ipsenone. Field experiments demonstrated that 1:1 combinations of (-)-ipsenol and (±)-ipsdienol

J. E. Macías-Sámano; J. H. Borden; R. Gries; G. Gries

1997-01-01

8

Caenorhabditis elegans as an Experimental Organism  

E-print Network

of an organism.) Life Cycle C. elegans is a nonparasitic terrestrial nematode that normally inhabits soil in the small nematode worm Caenorhabditis elegans has elucidated the mechanisms of many basic biological processes. Introduction The nematode worm Caenorhabditis elegans has been the subject of intensive molecular

Chisholm, Andrew

9

The glia of Caenorhabditis elegans  

PubMed Central

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, while 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. PMID:21732423

Oikonomou, Grigorios; Shaham, Shai

2010-01-01

10

Meiotic Development in Caenorhabditis elegans  

PubMed Central

Caenorhabditis elegans has become a powerful experimental organism with which to study meiotic processes that promote the accurate segregation of chromosomes during the generation of haploid gametes. Haploid reproductive cells are produced through one round of chromosome replication followed by two successive cell divisions. Characteristic meiotic chromosome structure and dynamics are largely conserved in C. elegans. Chromosomes adopt a meiosis-specific structure by loading cohesin proteins, assembling axial elements, and acquiring chromatin marks. Homologous chromosomes pair and form physical connections though synapsis and recombination. Synaptonemal complex and crossover formation allow for the homologs to stably associate prior to remodeling that facilitates their segregation. This chapter will cover conserved meiotic processes as well as highlight aspects of meiosis that are unique to C. elegans. PMID:22872477

Lui, Doris Y.

2013-01-01

11

Economics of static VAR compensation  

SciTech Connect

This project was initiated in anticipation of widened use of static VAR (volt-ampere-reactive) compensation on US bulk-power transmission systems to increase levels of secure power transfer. Project objectives were to deten-nine power system cost savings and reliability benefits resulting from such use. System operating cost and stability probabilities were compared with and without static VAR compensation, applying simulation techniques. For the particular system model studied, there was a 21.4 percent reduction in operating costs taking into account losses added by the static VAR compensator. A procedure was developed to compare instability probabilities for various loadings and static VAR compensator sizes on a power system. For the particular system model studied, the static VAR compensator provided a significant increase in stability but over a narrow range of loading. Static VAR compensation is one of a number of promising FACTS (Flexible AC Transmission System) technologies for handling the demands of increased power transfers on power systems where transmission lines cannot be built or as a short-term altemative to building additional lines.

Alvarado, F.L.; DeMarco, C.; Jung, T.H. (Wisconsin Univ., Madison, WI (United States). Dept. of Electrical and Computer Engineering)

1992-09-01

12

Antimicrobial peptides in Caenorhabditis elegans  

Microsoft Academic Search

The nematode Caenorhabditis elegans is one of the most successful model species for experimental research because of its sequenced genome, the versatile genetic toolkit and the straightforward breeding among others. In natural conditions however, this tiny worm is constantly surrounded by micro-organisms, simultaneously a source of indispensable nutrition and inevitable pathogens. Lacking an adaptive immune system, the worm solely relies

A Bogaerts; I Beets; L Schoofs; P Verleyen

2010-01-01

13

Variable Declaration var x: T P  

E-print Network

Variable Declaration var x: T· P 1/80 #12;Variable Declaration var x: T· P declare local state variable x with type T and scope P 2/80 #12;Variable Declaration var x: T· P declare local state variable x with type T and scope P = x, x: T· P 3/80 #12;Variable Declaration var x: T· P declare local state variable

Hehner, Eric C.R.

14

The elegans of spindle assembly  

PubMed Central

The Caenorhabditis elegans one-cell embryo is a powerful system in which to study microtubule organization because this large cell assembles both meiotic and mitotic spindles within the same cytoplasm over the course of 1 h in a stereotypical manner. The fertilized oocyte assembles two consecutive acentrosomal meiotic spindles that function to reduce the replicated maternal diploid set of chromosomes to a single-copy haploid set. The resulting maternal DNA then unites with the paternal DNA to form a zygotic diploid complement, around which a centrosome-based mitotic spindle forms. The early C. elegans embryo is amenable to live-cell imaging and electron tomography, permitting a detailed structural comparison of the meiotic and mitotic modes of spindle assembly. PMID:20339898

Greenan, Garrett; O'Toole, Eileen

2010-01-01

15

Zygomycosis caused by Apophysomyces elegans.  

PubMed

A case of zygomycosis caused by Apophysomyces elegans in a diabetic, obese female is described. The fungus gained entry into the body through injury to the skin, penetrating the keratin, epidermis, and dermis. Hyphal angioinvasion was observed. Fungal elements invaded the subcutaneous fat, skeletal muscle fibers, nerves, and large blood vessels, resulting in the spread of the infection. The rapidity with which A. elegans invaded the blood vessels left no choice except amputation of the leg to stop the spread of the infection. This zygomycetous fungus closely resembles Absidia corymbifera. It is distinguished by its prominent campanulate apophyses. In its gross colony characteristics and failure to sporulate on routinely used media it resembles Saksenaea vasiformis. PMID:4077963

Wieden, M A; Steinbronn, K K; Padhye, A A; Ajello, L; Chandler, F W

1985-10-01

16

Apophysomyces elegans: an Emerging Zygomycete in India  

Microsoft Academic Search

Apophysomyces elegans was considered a rare but medically important zygomycete. We analyzed the clinical records of eight patients from a single center in whom zygomycosis due to A. elegans was diagnosed over a span of 25 months. We also attempted a DNA-based method for rapid identification of the fungi and looked for interstrain polymorphism using microsattelite primers. Three patients had

A. Chakrabarti; A. Ghosh; G. S. Prasad; J. K. David; S. Gupta; A. Das; V. Sakhuja; N. K. Panda; S. K. Singh; S. Das; T. Chakrabarti

2003-01-01

17

Establishing in vitro Zinnia elegans cell suspension culture with high tracheary element differentiation.  

PubMed

The Zinnia elegans mesophyll cell culture is a useful system for xylogenesis studies. The system is associated with highly synchronous tracheary element (TE) differentiation, making it more suitable for molecular studies requiring larger amounts of molecular isolates, such as mRNA and proteins and for studying cellulose synthesis. There is, however, the problem of non-uniformity and significant variations in the yields of TEs (%TE). One possible cause for this variability in the %TE could be the lack of a standardized experimental protocol in various research laboratories for establishing the Zinnia culture. Mesophyll cells isolated from the first true leaves of Z. elegans var Envy seedlings of approximately 14 days old were cultured in vitro and differentiated into TEs. The xylogenic culture medium was supplied with 1mg/l each of benzylaminopurine (BA) and alpha-naphthalene acetic acid (NAA). Application of this improved culture method resulted in stable and reproducible amounts of TE as high as 76% in the Zinnia culture. The increase was mainly due to conditioning of the mesophyll cell culture and adjustments of the phytohormonal balance in the cultures. Also, certain biochemical and cytological methods have been shown to reliably monitor progress of TE differentiation. We conclude that, with the adoption of current improvement in the xylogenic Z. elegans culture, higher amounts of tracheary elements can be produced. This successful outcome raises the potential of the Zinnia system as a suitable model for cellulose and xylogenesis research. PMID:19232395

Twumasi, Peter; Schel, Jan H N; van Ieperen, Wim; Woltering, Ernst; Van Kooten, Olaf; Emons, Anne Mie C

2009-04-01

18

ACeKit: A Caenorhabditis elegans Survival Kit  

NSDL National Science Digital Library

Developed by elegans_Net, this metasite on _Caenorhabditis elegans provides everything you ever wanted to know about the model organism, including commentary by experts; the value of C. elegans to biology, biotechnology, and medicine; and links to major functional genomics and bioinformatics resources. Also at the site are links to text and images on the dynamics of C. elegans development, C. elegans anatomy, and other miscellany.

19

Electrical sorting of Caenorhabditis elegans.  

PubMed

The nematode (worm) C. elegans is one of the widely studied animal model organisms in biology. It develops through 4 larval stages (L1-L4) in 2 to 3 days before becoming a young adult. Biological assays involving C. elegans frequently require a large number of animals that are appropriately staged and exhibit a similar behaviour. We have developed a new method to synchronize animals that relies on the electrotactic response (electric field-induced motion) of C. elegans to sort them in parallel based on their age, size and phenotype. By using local electric field traps in a microfluidic device, we can efficiently sort worms from a mixed culture in a semi-continuous flow manner (with a minimum throughput of 78 worms per minute per load-run) and obtain synchronized populations of animals. In addition to sorting larvae, our device can also distinguish between young and old adults efficiently. Unlike fluorescent based sorting systems that use active imaging based feedback, this method is passive and automatic and uses the innate behaviour of the worm. Considering that the entire procedure takes only a few minutes to run and is cost-effective, it promises to simplify and accelerate experiments requiring homogeneous cultures of worms as well as to facilitate isolation of mutants that have abnormal electrotaxis. More importantly, our method of isolating and separating worms using locomotion as a defining characteristic promises development of advanced microfluidics-based systems to study the neuronal basis of movement-related defects in worms and facilitate high-throughput chemical screening and drug discovery. PMID:22460920

Rezai, Pouya; Salam, Sangeena; Selvaganapathy, Ponnambalam Ravi; Gupta, Bhagwati P

2012-04-24

20

Axon regeneration mechanisms: insights from C. elegans  

PubMed Central

Understanding the mechanisms of axon regeneration is of great importance to develop therapeutic treatments for spinal cord injury or stroke. Axon regeneration has long been studied in various vertebrate and invertebrate models, but until recently had not been analyzed in the genetically tractable model organism Caenorhabditis elegans. The small size, simple neuroanatomy, and transparency of C. elegans allows single fluorescently labeled axons to be severed in live animals using laser microsurgery. Many neurons in C. elegans are capable of regenerative regrowth, and can in some cases re-establish functional connections. Large-scale genetic screens have begun to elucidate the genetic basis of axon regrowth. PMID:21907582

Chen, Lizhen; Chisholm, Andrew D.

2011-01-01

21

Gait synchronization in Caenorhabditis elegans.  

PubMed

Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

Yuan, Jinzhou; Raizen, David M; Bau, Haim H

2014-05-13

22

Biotoxic activity in the Mucorales  

Microsoft Academic Search

The toxigenicity of representatives of 15 species of Mucorales (Absidia glauca, Actinomucor elegans, Cunninghamella elegans, Helicostylum piriforme, Mortierella isabellina, Mortierella (Mucor) rammaniana, Mucor hiemalis, Mucor mucedo, Mucor spinosus, Phycomyces blakesleeanus, Rhizopus oligosporus, Rhizopus stolonifer, Syncephalastrum racemosum, Thamnidium elegans, Zygorhynchus moelleri) towards the larvae of brine shrimp (Artemia salina) and the growth of pea seedlings (Pisum sativum) and tobacco plants (Nicotiana

J. Reiss

1993-01-01

23

The behavioral genetics of Caenorhabditis elegans  

Microsoft Academic Search

Caenorhabditis elegans, a small free-living soil nematode, is an ideal organism for the genetic dissection of simple behaviors. Over 150 genes required for normal behavior have been identified. We review here the neural and genetic pathways underlying four of the best-studiedC. elegans behaviors: locomotion, response to gentle touch, egg-laying, and chemotaxis. Mutations affecting these behaviors have identified genes which specify

Eve Wolinsky

1990-01-01

24

Biomechanical Profiling of Caenorhabditis elegans Motility  

PubMed Central

Caenorhabditis elegans locomotion is a stereotyped behavior that is ideal for genetic analysis. We integrated video microscopy, image analysis algorithms, and fluid mechanics principles to describe the C. elegans swim gait. Quantification of body shapes and external hydrodynamics and model-based estimates of biomechanics reveal that mutants affecting similar biological processes exhibit related patterns of biomechanical differences. Therefore, biomechanical profiling could be useful for predicting the function of previously unstudied motility genes. PMID:22554893

Krajacic, Predrag; Shen, Xiaoning; Purohit, Prashant K.; Arratia, Paulo; Lamitina, Todd

2012-01-01

25

Craniofacial zygomycosis caused by Apophysomyces elegans.  

PubMed

A fatal case of craniofacial zygomycosis caused by Apophysomyces elegans in a 52-year-old man was diagnosed by the presence of broad aseptate, branched hyaline hyphae in tissue from paranasal sinuses and surrounding areas, and isolation of the fungus from the same tissue. The patient suffered from idiopathic myelofibrosis as underlying disease, he was thrombocytopenic and was mildly hyperglycaemic. The infection represents the second case of craniofacial zygomycosis due to A. elegans. PMID:9470406

Chakrabarti, A; Panda, N; Varma, S C; Singh, K; Das, A; Sharma, S C; Padhye, A A

1997-12-01

26

The proximate determinants of sex ratio in C. elegans populations  

E-print Network

85721, USA (Received 20 August 2002 and in revised form 5 November 2002) Summary The soil nematode The bacteriophagous soil nematode Caenorhabditis elegans exhibits an androdioecious mode of repro- duction: C. elegans

Avilés, Leticia

27

An Automated Micropositioning System for Investigating C. elegans  

E-print Network

elegans online at a full 30 Hz. The employment of Gaussian Pyramid Level-2 images significantly reduces receptor that regulates so- cial behavior and food response in C. elegans. Pierce-Shimomura et al.5 used changes. Keywords: C. elegans tracking, Gaussian Pyramid images, visual feature extraction, cubic spline

Sun, Yu

28

Chemically defined medium and Caenorhabditis elegans  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

29

"Var Teatre"--A Pioneer Turns 40.  

ERIC Educational Resources Information Center

Describes the Stockholm Municipal Youth and Children's theatre ("Var Teatre"), an institution of 14 theatres and attendant professional staff devoted exclusively to drama activities for children and teenagers. (PD)

Jones, Pamela L.

1984-01-01

30

Rhinocerebral mucormycosis caused by Apophysomyces elegans.  

PubMed

Mucormycosis is an uncommon fungal disease and one of the most fulminant infections known. This is the second report of rhinocerebral mucormycosis caused by Apophysomyces elegans, a newly recognized genus and species classified in the family Mucoraceae. The patient was a 54-year-old man being treated for a severe sinus infection with antibiotics and oral steroids. Recovery occurred in our patient after prompt surgical debridement and drainage of his maxillary sinuses. This case fits the reported characteristics of other A. elegans infections including warm climate, intimate contact with the soil, and an incubation period measured in days. Several reported cases indicate A. elegans can cause mucormycosis in immunocompetent individuals with no underlying medical problems. PMID:9740925

Brown, S R; Shah, I A; Grinstead, M

1998-01-01

31

Neurotransmitter release mechanisms studied in Caenorhabditis elegans.  

PubMed

The process of regulated exocytosis has received considerable interest as a key component of synaptic transmission. Fusion of presynaptic vesicles and the subsequent release of their neurotransmitter contents is driven by a series of interactions between evolutionarily conserved proteins. Key insights into the molecular mechanisms of vesicle fusion have come from research using genetic model systems such as the nematode worm Caenorhabditis elegans. We review here the current knowledge regarding regulated exocytosis at the C. elegans synapse and future research directions involving this model organism. PMID:22521667

Barclay, Jeff W; Morgan, Alan; Burgoyne, Robert D

2012-01-01

32

Ascaroside signaling in C. elegans*  

PubMed Central

Over the past 10 years, the relevance of small-molecule signaling for many aspects of C. elegans development and behavior has become apparent. One prominent group of small-molecule signals are the ascarosides, which control dauer entry and exit as well as a variety of sex-specific and social behaviors, including male attraction, hermaphrodite repulsion, olfactory plasticity, and aggregation. This wide range of biological functions is facilitated by a great diversity of ascaroside chemical structures. These are based on the sugar ascarylose, which is linked to fatty acid-like side chains of varying lengths and often decorated further with building blocks derived from amino acids, folate, and other primary metabolites. Different ascarosides or combinations of ascarosides mediate different phenotypes, and even small differences in chemical structures are often associated with strongly altered activity profiles. Additional complexity arises from concentration-dependent effects and synergism between different ascarosides. The ascarosides are sensed by several types of chemosensory head neurons, including the ASK, ASI, and ADL neurons as well as the male-specific CEM neurons. Ascaroside perception is mediated by diverse families of G-protein coupled membrane receptors that act upstream of conserved signal transduction pathways, including insulin/IGF-1 signaling and transforming growth factor beta (TGF-?) signaling. Biosynthesis of the ascarosides appears to integrate input from several primary metabolic pathways, including peroxisomal ?-oxidation of long-chain fatty acids and amino acid catabolism. Life stage, sex, as well as food availability and other environmental factors affect ascaroside biosynthesis, suggesting that ascaroside signaling communicates detailed information about life history and metabolic state. PMID:23355522

Ludewig, Andreas H.; Schroeder, Frank C.

2013-01-01

33

Absence of Strong Heterosis for Life Span and Other Life History Traits in Caenorhabditis Elegans  

PubMed Central

We have examined crosses between wild-type strains of Caenorhabditis elegans for heterosis effects on life span and other life history traits. Hermaphrodites of all wild strains had similar life expectancies but males of two strains had shorter life spans than hermaphrodites while males of two other strains lived longer than hermaphrodites. F(1) hermaphrodite progeny showed no heterosis while some heterosis for longer life span was detected in F(1) males. F(1) hybrids of crosses between two widely studied wild-type strains, N2 (var. Bristol) and Berg BO (var. Bergerac), were examined for rate of development, hermaphrodite fertility, and behavior; there was no heterosis for these life history traits. Both controlled variation of temperature and uncontrolled environmental variation affected the length of life of all genotypes. Significant G X E effects on life span were observed in comparisons of N2 and Berg BO hermaphrodites, or N2 hermaphrodites and males, or N2 and a Ts mutant strain (DH26). Nevertheless, within an experiment, environmental variation was minimal and life spans were quite replicable. PMID:8325483

Johnson, T. E.; Hutchinson, E. W.

1993-01-01

34

Systematic functional analysis of the Caenorhabditis elegans  

E-print Network

, because more than half of the genes in C. elegans have a human homologue, this kind of functional analysis in the worm should provide insights into human gene function. Analysis of gene functions by RNAi Loss hermaphrodites to identify genes for which RNAi reproducibly results in sterility, embryonic or larval lethality

Ahringe, Julie

35

Immunoglobulin superfamily proteins in Caenorhabditis elegans1  

Microsoft Academic Search

The predicted proteins of the genome of Caenorhabditis elegans were ana- lysed by various sequence comparison methods to identify the repertoire of proteins that are members of the immunoglobulin superfamily (IgSF). The IgSF is one of the largest families of protein domain in this genome and likely to be one of the major families in other multicellular eukar- yotes too.

Sarah A. Teichmann; Cyrus Chothia

2000-01-01

36

Staphylococcal Biofilm Exopolysaccharide Protects against Caenorhabditis elegans  

E-print Network

Staphylococcal Biofilm Exopolysaccharide Protects against Caenorhabditis elegans Immune Defenses of staphylococci to produce biofilm is an important virulence mechanism that allows bacteria both to adhere that the icaADBC locus, which synthesizes the biofilm-associated polysaccharide intercellular adhesin (PIA

Ausubel, Frederick M.

37

Heterochronic Mutants of the Nematode Caenorhabditis elegans  

Microsoft Academic Search

Mutations in the Caenorhabditis elegans genes lin-14, lin-28, and lin-29 cause heterochronic developmental defects: the timing of specific developmental events in several tissues is altered relative to the timing of events in other tissues. These defects result from temporal transformations in the fates of specific cells, that is, certain cells express fates normally expressed by cells generated at other developmental

Victor Ambros; H. Robert Horvitz

1984-01-01

38

Movie of normal C. elegans development  

NSDL National Science Digital Library

C. elegans develops from a single cell, the fertilized egg, to a 558-celled worm in about 14 hours. The worm that crawls out of its eggshell has a functioning feeding apparatus, gut, nervous system and muscles. This movie shows that in time lapse.

PhD Bob Goldstein (UNC Chapel Hill Biology Dept,)

2006-07-19

39

Apophysomyces elegans: an Emerging Zygomycete in India  

PubMed Central

Apophysomyces elegans was considered a rare but medically important zygomycete. We analyzed the clinical records of eight patients from a single center in whom zygomycosis due to A. elegans was diagnosed over a span of 25 months. We also attempted a DNA-based method for rapid identification of the fungi and looked for interstrain polymorphism using microsattelite primers. Three patients had cutaneous and subcutaneous infections, three had isolated renal involvement, one had rhino-orbital tissue infection, and the final patient had a disseminated infection involving the spleen and kidney. Underlying illnesses were found in two patients, one with diabetes mellitus and the other with chronic alcoholism. A history of traumatic implantation was available for three patients. All except two of the patients responded to surgical and/or medical therapy; the diagnosis for the two exceptions was made at the terminal stage of infection. Restriction enzyme (MboI, MspI, HinfI) digestion of the PCR-amplified internal transcribed spacer region helped with the rapid and specific identification of A. elegans. The strains could be divided into two groups according to their patterns, with clustering into one pattern obtained by using microsatellite [(GTG)5 and (GAC)5] PCR fingerprinting. The study highlights the epidemiology, clinical spectrum, and diagnosis of emerging A. elegans infections. PMID:12574283

Chakrabarti, A.; Ghosh, A.; Prasad, G. S.; David, J. K.; Gupta, S.; Das, A.; Sakhuja, V.; Panda, N. K.; Singh, S. K.; Das, S.; Chakrabarti, T.

2003-01-01

40

Burn wound zygomycosis caused by Apophysomyces elegans.  

PubMed

A case of zygomycosis caused by Apophysomyces elegans in a patient having 25% full-thickness burns is described. Amputation of the leg was necessary to control rapid tissue invasion. The fungus was isolated from soil in the burn environment. PMID:2229400

Cooter, R D; Lim, I S; Ellis, D H; Leitch, I O

1990-09-01

41

Apophysomyces elegans: an emerging zygomycete in India.  

PubMed

Apophysomyces elegans was considered a rare but medically important zygomycete. We analyzed the clinical records of eight patients from a single center in whom zygomycosis due to A. elegans was diagnosed over a span of 25 months. We also attempted a DNA-based method for rapid identification of the fungi and looked for interstrain polymorphism using microsattelite primers. Three patients had cutaneous and subcutaneous infections, three had isolated renal involvement, one had rhino-orbital tissue infection, and the final patient had a disseminated infection involving the spleen and kidney. Underlying illnesses were found in two patients, one with diabetes mellitus and the other with chronic alcoholism. A history of traumatic implantation was available for three patients. All except two of the patients responded to surgical and/or medical therapy; the diagnosis for the two exceptions was made at the terminal stage of infection. Restriction enzyme (MboI, MspI, HinfI) digestion of the PCR-amplified internal transcribed spacer region helped with the rapid and specific identification of A. elegans. The strains could be divided into two groups according to their patterns, with clustering into one pattern obtained by using microsatellite [(GTG)(5) and (GAC)(5)] PCR fingerprinting. The study highlights the epidemiology, clinical spectrum, and diagnosis of emerging A. elegans infections. PMID:12574283

Chakrabarti, A; Ghosh, A; Prasad, G S; David, J K; Gupta, S; Das, A; Sakhuja, V; Panda, N K; Singh, S K; Das, S; Chakrabarti, T

2003-02-01

42

Comparative Toxicology of Mercurials in Caenorhabditis elegans  

PubMed Central

Mercury is a toxic metal that can exist in multiple chemical species. Humans are commonly exposed to methylmercury and mercury vapor, which is converted to mercuric mercury in the body. Despite years of research, there is a paucity of information on the similarity and differences in the mechanisms of mercury toxicity. The relative toxicity of mercuric chloride (HgCl2) and methylmercury chloride (MeHgCl) in C. elegans was determined using assays that measured growth, feeding, reproduction, and locomotion. The effect of HgCl2 and MeHgCl on the expression of several archetypal stress-response genes was also determined. There was no significant difference between the EC50s of the two mercurials on C. elegans growth. However, MeHgCl was more toxic to C. elegans than HgCl2 when assessing feeding, movement and reproduction, all of which require proper neuromuscular activity. Methylmercury chloride exposure resulted in increased steady-state levels of the stress response genes at lower concentrations than HgCl2. In general, MeHgCl was more toxic to C. elegans than HgCl2, particularly when assaying behaviors that require neuromuscular function. PMID:21692103

McElwee, Matthew K.; Freedman, Jonathan H.

2011-01-01

43

Characterization of the C. elegans erlin homologue  

PubMed Central

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 essential component of the general ERAD pathway. Conclusions Although loss of erlin function apparently causes a strong phenotype in humans, no such effect is seen in C. elegans. C. elegans erlin does not appear to be a ubiquitous major modulator of IP3 receptor activity nor does erlin appear to play a major role in ERAD. PMID:22269071

2012-01-01

44

Volatiles of Chrysanthemum zawadskii var. latilobum K.  

PubMed

The volatile aroma constituents of Chrysanthemum zawadskii var. latilobum K. were separated by hydro distillation extraction (HDE) method using a Clevenger-type apparatus, and analyzed by gas chromatography-mass spectrometry (GC/MS). The yield of C. zawadskii var. latilobum K. flower essential oil (FEO) was 0.12% (w/w) and the color was light green. Fifty-five volatile chemical components, which make up 88.38% of the total aroma composition, were tentatively characterized. C. zawadskii var. latilobum K. FEOs contained 27 hydrocarbons, 12 alcohols, 7 ketones, 4 esters, 1 aldehyde, 1 amine, and 3 miscellaneous components. The major functional groups were terpene alcohol and ketone. Borneol (12.96), (±)-7-epi-amiteol (12.60), and camphor (10.54%) were the predominant volatiles. These compounds can be used in food and pharmaceutical industries due to their active bio-functional properties. PMID:24471090

Chang, Kyung-Mi; Kim, Gun-Hee

2012-09-01

45

Why are there males in the hermaphroditic species Caenorhabditis elegans?  

PubMed Central

The free-living nematode worm Caenorhabditis elegans reproduces primarily as a self-fertilizing hermaphrodite, yet males are maintained in wild-type populations at low frequency. To determine the role of males in C. elegans, we develop a mathematical model for the genetic system of hermaphrodites that can either self-fertilize or be fertilized by males and we perform laboratory observations and experiments on both C. elegans and a related dioecious species C. remanei. We show that the mating efficiency of C. elegans is poor compared to a dioecious species and that C. elegans males are more attracted to C. remanei females than they are to their conspecific hermaphrodites. We postulate that a genetic mutation occurred during the evolution of C. elegans hermaphrodites, resulting in the loss of an attracting sex pheromone present in the ancestor of both C. elegans and C. remanei. Our findings suggest that males are maintained in C. elegans because of the particular genetic system inherited from its dioecious ancestor and because of nonadaptive spontaneous nondisjunction of sex chromosomes, which occurs during meiosis in the hermaphrodite. A theoretical argument shows that the low frequency of male mating observed in C. elegans can support male-specific genes against mutational degeneration. This results in the continuing presence of functional males in a 99.9% hermaphroditic species in which outcrossing is disadvantageous to hermaphrodites. PMID:11901116

Chasnov, J R; Chow, King L

2002-01-01

46

Bacteria and the Aging and Longevity of Caenorhabditis elegans  

E-print Network

The molecular genetic analysis of longevity of Caenorhabditis elegans has yielded fundamental insights into evolutionarily conserved pathways and processes governing the physiology of aging. Recent studies suggest that ...

Kim, Dennis H.

47

Power electronics in electric utilities: Static var compensators  

Microsoft Academic Search

This paper deals with dynamic var compensation of electric power systems, applying power electronics for reactive power generation and control. After an overview of the emergence and status of modern, solid-state var compensators in utility and industrial applications, the first part of the paper explains how dynamic var compensation increases transmittable power by providing voltage support, transient stability improvement, and

L. Gyugyi

1988-01-01

48

Evaluation of the hepatoprotective and antioxidant activity of Boehmeria nivea var. nivea and B. nivea var. tenacissima  

Microsoft Academic Search

In this study, the relationship between liver protective effects and antioxidant activity of Boehmeria nivea var. nivea (=B. nivea) and B. nivea var. tenacissima (=B. frutescens) was investigated. The water extracts of both plants exhibited a hepatoprotective activity against CCl4-induced liver injury. B. nivea var. nivea and B. nivea var. tenacissima, also showed anti-oxidant effects in FeCl2-ascorbate induced lipid peroxidation

Chun-Ching Lin; Ming-Hong Yen; Tsae-shiuan Lo; Jer-Min Lin

1998-01-01

49

DEVELOPING IMPROVED METHODS OF PROCESSING AND UTILIZATION OF KERNELS OF IRVINGIA GABONENSIS (VAR. GABONENSIS AND VAR. EXCELSA)  

Microsoft Academic Search

Kernels of two varieties of an economic farm tree Irvingia gabonensis, namely, var. gabonensis (ugiri) and var. excelsa (ogbono), were processed into flour after defatting. The kernels are the source of an important soup condiment and the fruit pulp of var. gabonensis is eaten when ripe. Samples were analysed for moisture and nutrient contents before and after 9 months shelf-life

M. A. N. EJIOFOR; S. N. ONWUBUKE; J. C. OKAFOR

1987-01-01

50

Caenorhabditis Elegans--Applications to Nematode Genomics  

PubMed Central

The complete genome sequence of the free-living nematode Caenorhabditis elegans was published 4 years ago. Since then, we have seen great strides in technologies that seek to exploit this data. Here we describe the application of some of these techniques and other advances that are helping us to understand about not only the biology of this important model organism but also the entire phylum Nematoda. PMID:18629128

Parkinson, John

2003-01-01

51

Circadian stress tolerance in adult Caenorhabditis elegans  

Microsoft Academic Search

Circadian rhythms control several behaviors through neural networks, hormones and gene expression. One of these outputs in\\u000a invertebrates, vertebrates and plants is the stress resistance behavior. In this work, we studied the circadian variation\\u000a in abiotic stress resistance of adult C. elegans as well as the genetic mechanisms that underlie such behavior. Measuring the stress resistance by tap response behavior

Sergio H. Simonetta; Andrés Romanowski; Alicia N. Minniti; Nibaldo C. Inestrosa; Diego A. Golombek

2008-01-01

52

Benzophenone O-glycosides from Hypericum elegans  

Microsoft Academic Search

Elegaphenonoside, a new benzophenone O-rhamnoside, together with two known benzophenone O-glycosides, namely hypericophenonoside and neoannulatophenonoside, were isolated from the aerial parts of Hypericum elegans Stephan ex Willd. The structure of the new compound was established as 3?,5?,6-trihydroxy-4-methoxybenzophenone-2-O-?-L-rhamnopyranoside by means of chemical and physical evidence. In addition, the presence of kaempferol, quercetin, isoquercitrin, norathyriol, I-3,II-8-biapigenin, quercitrin, hyperoside and rutin were established

Paraskev T. Nedialkov; Dimitrina Zheleva-Dimitrova; Ulrich Girreser; Gerassim M. Kitanov

2009-01-01

53

A database of C. elegans behavioral phenotypes  

PubMed Central

Using low-cost automated tracking microscopes, we have generated a behavioral database for 305 C. elegans strains, including 76 mutants with no previously described phenotype. The database consists of 9,203 short videos segmented to extract behavior and morphology features that are available online for further analysis. The database also includes summary statistics for 702 measures with statistical comparisons to wild-type controls so that phenotypes can be identified and understood by users. PMID:23852451

Yemini, Eviatar; Jucikas, Tadas; Grundy, Laura J.; Brown, Andre E.X.; Schafer, William R.

2014-01-01

54

Modeling neurodegenerative diseases in Caenorhabditis elegans.  

PubMed

Neurodegenerative diseases which include Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington disease (HD), and others are becoming an increasing threat to human health worldwide. The degeneration and death of certain specific groups of neurons are the hallmarks of these diseases. Despite the research progress in identification of several disease-related genes, the mechanisms underlying the neurodegeneration in these diseases remain unclear. Given the molecular conservation in neuronal signaling between Caenorhabditis elegans and vertebrates, an increasing number of research scientists have used the nematode to study this group of diseases. This review paper will focus on the model system that has been established in C. elegans to investigate the pathogenetic roles of those reported disease-related genes in AD, PD, ALS, HD and others. The progress in C. elegans provides useful information of the genetic interactions and molecular pathways that are critical in the disease process, and may help better our understanding of the disease mechanisms and search for new therapeutics for these devastating diseases. PMID:24095843

Li, Jia; Le, Weidong

2013-12-01

55

In vivo imaging of C. elegans endocytosis.  

PubMed

Over the past decade, the early Caenorhabditis elegans embryo has proven to be a useful animal model to study a variety of membrane trafficking events, at least in part due to its large size, optical transparency, and ease of manipulation. Importantly, the stereotypic nature of membrane remodeling that occurs during early embryogenesis has enabled quantitative measurement of endocytic flux. In the absence of exogenous stimulation, resumption of the cell cycle triggered by fertilization is coupled to a dramatic redistribution of plasma membrane content. Numerous proteins are rapidly internalized via clathrin-mediated endocytosis, and the fate of these cargoes can be followed precisely using live imaging in utero. Key to these studies is the maintenance of animal health and their immobilization, which can become technically challenging during extended imaging sessions. Here we highlight recent advances in live imaging techniques that have facilitated the interrogation of endocytic transport in live animals. We focus on the use of transgenic C. elegans strains that stably express fluorescently-tagged proteins, including components of the endosomal system and cargo molecules that traverse this network of membranes. Our findings demonstrate the utility of the C. elegans embryo in defining regulatory mechanisms that control the numerous steps of endocytic trafficking. PMID:24704355

Wang, Lei; Audhya, Anjon

2014-08-01

56

Chemical mating cues in C. elegans.  

PubMed

In the natural environment it is vital that organisms are capable of locating mates to reproduce and, consequently, increase the diversity of their gene pool. Many species make use of audio and visual communication for mate location. However, the more ancient form of chemical communication is used by all forms of life, from bacteria to mammals. In the past decade, much information has been discovered regarding pheromones in the nematode Caenorhabditis elegans. In this review, chemical signals that govern mating behavior in C. elegans will be discussed, from the existence and identification of mating cues, to the neurons involved in the behavioral response. Specifically, mate attraction is dictated by specific glycosides and side chains of the dideoxysugar ascarylose, a class of molecules known as ascarosides. Intriguingly, modifications of the ascarosides can dictate different behaviors such as male attraction, hermaphrodite attraction, and dauer formation. In general, interactions between core sensory neurons such as ASK and sex-specific neurons like CEM are critical for detecting these small molecules. These data reveal the existence of a complex, synergistic, chemical mating cue system between males and hermaphrodites in C. elegans, thereby highlighting the importance of mate attraction in a primarily hermaphroditic population. PMID:24977334

Chute, Christopher D; Srinivasan, Jagan

2014-09-01

57

Stable nuclear transformation of Eudorina elegans  

PubMed Central

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 inducible expression of the co-bombarded gluc gene was demonstrated by transcription analysis and bioluminescence assays. Conclusions Heterologous flanking sequences, including promoters, work in E. elegans and permit both constitutive and inducible expression of heterologous genes. Stable nuclear transformation of E. elegans is now routine. Thus, we show that genetic engineering of a species is possible even without the resources of endogenous genes and promoters. PMID:23402598

2013-01-01

58

C. elegans as a model organism Jonathan Hodgkin  

E-print Network

elegans: A tiny nematode or roundworm; lives in garden soil, feeding on bacteria #12;Biological and economic importance of nematodes C. elegans is a harmless free-living species, but: · Related nematodes are major parasites · At least 30% of the world's population carry nematode infections · Human diseases

Goldschmidt, Christina

59

INNATE IMMUNITY IN C. ELEGANS Ilka Engelmann and Nathalie Pujol*  

E-print Network

immune response of the C. elegans epidermis. INTRODUCTION C. elegans is a freeliving soil nematode and effector molecules involved in the nematode immune response, with a particular focus on the antifungal hemocytes, which engulf invading microbes, the only cells in the nematode body cavity, the 6 coelomocytes

Ewbank, Jonathan

60

Formation of Phosphoglycosides in Caenorhabditis elegans: A Novel Biotransformation Pathway  

PubMed Central

Background Caenorhabditis elegans (C. elegans) has become a widely used model to explore the effect of food constituents on health as well as on life-span extension. The results imply that besides essential nutrients several flavonoids are able to impact the aging process. What is less investigated is the bioavailability and biotransformation of these compounds in C. elegans. In the present study, we focused on the soy isoflavone genistein and its metabolism in the nematode as a basis for assessing whether this model system mimics the mammalian condition. Principal Findings C. elegans was exposed to 100 µM genistein for 48 hours. The worm homogenate was extracted and analyzed by liquid chromatography (LC). 11 metabolites of genistein were detected and characterized using LC electrospray ionization mass spectrometry. All genistein metabolites formed by C. elegans were found to be sugar conjugates, primarily genistein-O-glucosides. The dominant metabolite was identified as genistein-7-O-phosphoglucoside. Further interesting metabolites include two genistein-di-O-glycosides, a genistein-O-disaccharide as well as a genistein-O-phosphodisaccharide. Conclusions/Significance Our study provides evidence for a novel biotransformation pathway in C. elegans leading to conjugative metabolites which are not known for mammals. The metabolism of genistein in mammals and in C. elegans differs widely which may greatly impact the bioactivity. These differences need to be appropriately taken into consideration when C. elegans is used as a model to assess possible health or aging effects. PMID:23082135

Grunz, Gregor; Bunzel, Diana; Daniel, Hannelore; Kulling, Sabine E.

2012-01-01

61

Decline of nucleotide excision repair capacity in aging Caenorhabditis elegans  

Microsoft Academic Search

BACKGROUND: Caenorhabditis elegans is an important model for the study of DNA damage and repair related processes such as aging, neurodegeneration, and carcinogenesis. However, DNA repair is poorly characterized in this organism. We adapted a quantitative polymerase chain reaction assay to characterize repair of DNA damage induced by ultraviolet type C (UVC) radiation in C. elegans, and then tested whether

Joel N Meyer; Windy A Boyd; Gregory A Azzam; Astrid C Haugen; Jonathan H Freedman; Bennett Van Houten

2007-01-01

62

Tackling both sides of the hostpathogen equation with Caenorhabditis elegans  

E-print Network

that exist between host and pathogen, the nematode worm Caenorhabditis elegans is perhaps not the first model animal Caenorhabditis elegans is a free-living (as opposed to parasitic) hermaphroditic nematode, which if the temperature is lower. Worms can be vortexed, centrifuged, and frozen. They can also be grown in liquid culture

Ewbank, Jonathan

63

Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen*  

E-print Network

CHAPTER 6 Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen* , Christopher V. Identifying Cells in C. elegans III. Laser Ablation Theory and Apparatus A. Tissue Damage by Nanosecond and Femtosecond Lasers B. The Laser Apparatus IV. Laser Killing of Cells A. Procedures B. Experimental Design

Fang-Yen, Christopher

64

Membrane Topology of the C. elegans SEL-12 Presenilin  

Microsoft Academic Search

Mutant presenilins cause Alzheimer's disease. Presenilins have multiple hydrophobic regions that could theoretically span a membrane, and a knowledge of the membrane topology is crucial for deducing the mechanism of presenilin function. By analyzing the activity of ?-galactosidase hybrid proteins expressed in C. elegans, we show that the C. elegans SEL-12 presenilin has eight transmembrane domains and that there is

Xiajun Li; Iva Greenwald

1996-01-01

65

trt-1 Is the Caenorhabditis elegans Catalytic Subunit of Telomerase  

E-print Network

is exacerbated in patients with Werner's progeria (a segmental aging syndrome), and the in vitro premature a variety of premature aging phenotypes in only a few generations [9,10]. These results provide compelling postmitotic aging in C. elegans. These findings illustrate effects of telomere dysfunction in C. elegans

Gartner, Anton

66

Glianeuron interactions in the nervous system of Caenorhabditis elegans  

E-print Network

Author's personal copy Glia­neuron interactions in the nervous system of Caenorhabditis elegans their intricate and important roles in nervous system development and function. Recent studies in the nematode, functional and molecular features of the nervous systems between C. elegans and vertebrates, these recent

Shaham, Shai

67

Selection against males in Caenorhabditis elegans under two mutational treatments  

E-print Network

Selection against males in Caenorhabditis elegans under two mutational treatments Diogo Manoel1 such as severe inbreeding depression is present. In this study, we consider the relationship between elegans. This species is characterized by an androdioecious breeding system composed of males at low

Phillips, Patrick

68

nhl-2 Modulates MicroRNA Activity in Caenorhabditis elegans  

E-print Network

nhl-2 Modulates MicroRNA Activity in Caenorhabditis elegans Christopher M. Hammell,1 Isabella Lubin, Australia *Correspondence: victor.ambros@umassmed.edu DOI 10.1016/j.cell.2009.01.053 SUMMARY TRIM-NHL that a C. elegans TRIM- NHL protein, NHL-2, functions as a cofactor for the microRNA-induced silencing

Blackwell, Keith

69

RNAi As a Tool for Understanding Germline Development in Caenorhabditis elegans  

E-print Network

development in the nematode, Caenorhabditis elegans, and discusses the uses and limitations of RNAi a specific context: the study of germline development in the soil nematode, Caenorhabdi- tis elegans culture, the homologous C. elegans enzymes will no doubt be analyzed soon. In C. elegans, RNAi experiments

Maine, Eleanor

70

Caenorhabditis elegans as a model in developmental toxicology.  

PubMed

A number of practical advantages have made the nematode Caenorhabditis elegans a useful model for genetic and developmental biological research. These same advantages, along with conservation of disease and stress response pathways, availability of mutant and transgenic strains, and wealth of biological information, have led to the increased use of C. elegans in toxicological studies. Although the potential to study the mechanisms of developmental toxicology in C. elegans is promising, embryonic and larval growth tests to identify compounds that affect the nematode have remained the primary use of C. elegans in developmental toxicology. Here, we describe a C. elegans larval growth and development assay for medium- and high-throughput screening using the COPAS Biosort flow cytometer and provide descriptions of the data and subsequent analysis. PMID:22669657

Boyd, Windy A; Smith, Marjolein V; Freedman, Jonathan H

2012-01-01

71

C. elegans behavior of preference choice on bacterial food.  

PubMed

Caenorhabditis elegans is a free living soil nematode and thus in its natural habitat, C. elegans encounters many different species of soil bacteria. Although some soil bacteria may be excellent sources of nutrition for the worm, others may be pathogenic. Thus, we undertook a study to understand how C. elegans can identify their preferred food using a simple behavioral assay. We found that there are various species of soil bacteria that C. elegans prefers in comparison to the standard laboratory E. coli strain OP50. In particular, two bacterial strains, Bacillus mycoides and Bacillus soli, were preferred strains. Interestingly, the sole feeding of these bacteria to wild type animals results in extended lifespan through the activation of the autophagic process. Further studies will be required to understand the precise mechanism controlling the behavior of identification and selection of food in C. elegans. PMID:19756391

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

2009-09-01

72

Bioactive constituents of Cirsium japonicum var. australe.  

PubMed

Cirsium japonicum var. australe, used as a folk medicine in Taiwan, has been employed traditionally in the treatment of diabetes and inflammatory symptoms. Bioactivity-guided fractionation of its ethanolic extract, utilizing centrifugal partition chromatography monitored by DPPH-TLC analysis, led to the isolation of three new acetylenic phenylacrylic acid esters (1-3) and two new polyacetylenes (4 and 5), together with seven known compounds (6-12). The structures of 1-5 were elucidated by spectroscopic methods including 1D and 2D NMR techniques. The absolute configurations of 4 and 7 were determined utilizing Mosher's method and ECD/CD experiments. The DPPH scavenging activity of the constituents isolated from the C. japonicum var. australe ethanolic extract was evaluated. The potential antidiabetic activity of some of the isolates was evaluated using in vitro cellular glucose uptake and oil red staining assays. PMID:25025240

Lai, Wan-Chun; Wu, Yang-Chang; Dankó, Balázs; Cheng, Yuan-Bin; Hsieh, Tusty-Jiuan; Hsieh, Chi-Ting; Tsai, Yu-Chi; El-Shazly, Mohamed; Martins, Ana; Hohmann, Judit; Hunyadi, Attila; Chang, Fang-Rong

2014-07-25

73

Methoxylation enhances stilbene bioactivity in Caenorhabditis elegans  

PubMed Central

Background Stilbenes are 1,2-diphenylethylene congeners produced by plants in response to stress. Many stilbenes also exhibit xenobiotic activities in animal cells, such as inhibition of cancer cell growth, neuroprotection, and immune modulation. In vivo, hydroxylated stilbenes are metabolized by glucuronidation to facilitate excretion. Methoxylated stilbenes are metabolized more slowly, which may have a positive effect on in vivo bioactivity. Here, we have directly compared in vivo bioactivities of methoxylated and hydroxylated stilbenes in a whole organism using the roundworm Caenorhabditis elegans, an advantageous experimental system for such studies due to its rapid lifecycle, genetic amenability and relatively low-cost. Results Toxicity towards C. elegans adults was observed for trimethoxylated and dimethoxylated stilbenes, as well as the monomethoxylated stilbene desoxyrhapontigenin. Toxicity was not observed for the monomethoxylated stilbene, pinostilbene, nor for hydroxylated stilbenes. The methoxylated stilbenes that exhibited toxicity also showed stronger inhibitory effects than the hydroxylated stilbenes on germline tumor growth in gld-1(q485) adults. However, steady-state levels of three inhibitory methoxylated stilbenes did not directly correlate to their relative bioactivities. Conclusion These findings demonstrate that, for the group of stilbenes investigated, methoxylation generally increased bioactivity in vivo in a whole organism, with the exception of pinostilbene. Differences in bioactivity in C. elegans adults did not appear to correlate with differential uptake. Rather, we speculate that methoxylated stilbenes may have increased interactions with biological targets in vivo or may interact with specific targets unaffected by hydroxylated stilbenes. The potent activities of methoxylated stilbenes provide a basis for further investigations to identify in vivo targets for these compounds. PMID:18700960

Wilson, Mark A; Rimando, Agnes M; Wolkow, Catherine A

2008-01-01

74

Zygomycotic necrotizing fasciitis caused by Apophysomyces elegans.  

PubMed Central

A case of necrotizing fasciitis of the anterior abdominal wall caused by the zygomycete Apophysomyces elegans in a healthy male following inguinal herniorrhaphy is reported. The portal of entry of the fungus into the incised skin and subcutaneous tissues was probably through either contaminated surgical sutures or postoperative surgical dressings. Broad, aseptate fungal hyphae were seen in the necrosed tissues with an associated necrotizing vasculitis. Extensive tissue debridements and a low dose of amphotericin B were not successful in controlling the rapid invasion of the tissues by the fungus. Images PMID:8501244

Lakshmi, V; Rani, T S; Sharma, S; Mohan, V S; Sundaram, C; Rao, R R; Satyanarayana, G

1993-01-01

75

Systemic zygomycosis caused by Apophysomyces elegans.  

PubMed

A case of systemic zygomycosis caused by Apophysomyces elegans in a 56-year-old man is described. The left kidney and the bladder showed presence of broad, nonseptate-to-infrequently septate hyphae in both the bladder lesion and in the septic kidney. Surgical debridement and treatment with amphotericin B cured the infection. No underlying immune defect was ever demonstrated, and the patient was not hyperglycemic or acidotic at any time. This zygomycetous fungus closely resembles Absidia corymbifera, but is distinguished by its distinctive morphological features. PMID:3701543

Lawrence, R M; Snodgrass, W T; Reichel, G W; Padhye, A A; Ajello, L; Chandler, F W

1986-02-01

76

Fatal cellulitis caused by Apophysomyces elegans.  

PubMed

A case of cellulitis of the left lateral side of the face caused by the zygomycete Apophysomyces elegans in a healthy male following a road traffic accident is reported. The contaminated soil was the source of fungus. Broad aseptate fungal hyphae were seen in the necrosed tissues. Extensive tissue debridement and treatment with amphotericin B were not successful in controlling the rapid invasion of the tissues by the fungus. Patient developed angioinvasion, severe cellulitis and finally succumbed to the infection three weeks after admission. PMID:17901654

Kindo, A J; Shams, N R; Kumar, K; Kannan, S; Vidya, S; Kumar, A R; Kalyani, J

2007-07-01

77

Zygomycotic necrotizing fasciitis caused by Apophysomyces elegans.  

PubMed

A case of necrotizing fasciitis of the anterior abdominal wall caused by the zygomycete Apophysomyces elegans in a healthy male following inguinal herniorrhaphy is reported. The portal of entry of the fungus into the incised skin and subcutaneous tissues was probably through either contaminated surgical sutures or postoperative surgical dressings. Broad, aseptate fungal hyphae were seen in the necrosed tissues with an associated necrotizing vasculitis. Extensive tissue debridements and a low dose of amphotericin B were not successful in controlling the rapid invasion of the tissues by the fungus. PMID:8501244

Lakshmi, V; Rani, T S; Sharma, S; Mohan, V S; Sundaram, C; Rao, R R; Satyanarayana, G

1993-05-01

78

Characterization of the effects of methylmercury on Caenorhabditis elegans  

SciTech Connect

The rising prevalence of methylmercury (MeHg) in seafood and in the global environment provides an impetus for delineating the mechanism of the toxicity of MeHg. Deleterious effects of MeHg have been widely observed in humans and in other mammals, the most striking of which occur in the nervous system. Here we test the model organism, Caenorhabditis elegans (C. elegans), for MeHg toxicity. The simple, well-defined anatomy of the C. elegans nervous system and its ready visualization with green fluorescent protein (GFP) markers facilitated our study of the effects of methylmercuric chloride (MeHgCl) on neural development. Although MeHgCl was lethal to C. elegans, induced a developmental delay, and decreased pharyngeal pumping, other traits including lifespan, brood size, swimming rate, and nervous system morphology were not obviously perturbed in animals that survived MeHgCl exposure. Despite the limited effects of MeHgCl on C. elegans development and behavior, intracellular mercury (Hg) concentrations ({<=} 3 ng Hg/mg protein) in MeHgCl-treated nematodes approached levels that are highly toxic to mammals. If MeHgCl reaches these concentrations throughout the animal, this finding indicates that C. elegans cells, particularly neurons, may be less sensitive to MeHgCl toxicity than mammalian cells. We propose, therefore, that C. elegans should be a useful model for discovering intrinsic mechanisms that confer resistance to MeHgCl exposure.

Helmcke, Kirsten J. [Pharmacology Department, Vanderbilt University Medical Center, Nashville, TN (United States); Syversen, Tore [Department of Neuromedicine, Norwegian University of Science and Technology, Trondheim (Norway); Miller, David M. [Department of Cell and Developmental Biology and Program in Neuroscience, Vanderbilt University Medical Center, Nashville, TN (United States); Aschner, Michael [Pharmacology Department, Vanderbilt University Medical Center, Nashville, TN (United States); Pediatrics Department, Vanderbilt University Medical Center, Nashville, TN (United States)], E-mail: Michael.Aschner@vanderbilt.edu

2009-10-15

79

Microsporidia Are Natural Intracellular Parasites of the Nematode Caenorhabditis elegans  

PubMed Central

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. PMID:19071962

Troemel, Emily R; Felix, Marie-Anne; Whiteman, Noah K; Barriere, Antoine; Ausubel, Frederick M

2008-01-01

80

Apophysomyces elegans infection in a renal transplant recipient.  

PubMed

A 50-year-old cadaveric renal transplant recipient on immunosuppressive therapy is described with post-traumatic cutaneous infection caused by Apophysomyces elegans. He showed no evidence of hematogenous dissemination and recovered fully after therapy with extensive local debridement and amphotericin B lipid complex. An apparent drug-drug interaction between amphotericin B lipid complex and cyclosporine was encountered. The course of A elegans infection in transplant recipients may be similar to that described in immunocompetent hosts. A elegans infection should be considered in evaluation of post-traumatic cutaneous infection not readily responsive to antibacterial therapy. PMID:7645546

Naguib, M T; Huycke, M M; Pederson, J A; Pennington, L R; Burton, M E; Greenfield, R A

1995-08-01

81

Widespread Genomic Incompatibilities in Caenorhabditis elegans  

PubMed Central

In the Bateson-Dobzhansky-Muller (BDM) model of speciation, incompatibilities emerge from the deleterious interactions between alleles that are neutral or advantageous in the original genetic backgrounds, i.e., negative epistatic effects. Within species such interactions are responsible for outbreeding depression and F2 (hybrid) breakdown. We sought to identify BDM incompatibilities in the nematode Caenorhabditis elegans by looking for genomic regions that disrupt egg laying; a complex, highly regulated, and coordinated phenotype. Investigation of introgression lines and recombinant inbred lines derived from the isolates CB4856 and N2 uncovered multiple incompatibility quantitative trait loci (QTL). These QTL produce a synthetic egg-laying defective phenotype not seen in CB4856 and N2 nor in other wild isolates. For two of the QTL regions, results are inconsistent with a model of pairwise interaction between two loci, suggesting that the incompatibilities are a consequence of complex interactions between multiple loci. Analysis of additional life history traits indicates that the QTL regions identified in these screens are associated with effects on other traits such as lifespan and reproduction, suggesting that the incompatibilities are likely to be deleterious. Taken together, these results indicate that numerous BDM incompatibilities that could contribute to reproductive isolation can be detected and mapped within C. elegans. PMID:25128438

Snoek, L. Basten; Orbidans, Helen E.; Stastna, Jana J.; Aartse, Aafke; Rodriguez, Miriam; Riksen, Joost A.G.; Kammenga, Jan E.; Harvey, Simon C.

2014-01-01

82

C. elegans Tracking and Behavioral Measurement  

PubMed Central

We have developed instrumentation, image processing, and data analysis techniques to quantify the locomotory behavior of C. elegans as it crawls on the surface of an agar plate. For the study of the genetic, biochemical, and neuronal basis of behavior, C. elegans is an ideal organism because it is genetically tractable, amenable to microscopy, and shows a number of complex behaviors, including taxis, learning, and social interaction1,2. Behavioral analysis based on tracking the movements of worms as they crawl on agar plates have been particularly useful in the study of sensory behavior3, locomotion4, and general mutational phenotyping5. Our system works by moving the camera and illumination system as the worms crawls on a stationary agar plate, which ensures no mechanical stimulus is transmitted to the worm. Our tracking system is easy to use and includes a semi-automatic calibration feature. A challenge of all video tracking systems is that it generates an enormous amount of data that is intrinsically high dimensional. Our image processing and data analysis programs deal with this challenge by reducing the worms shape into a set of independent components, which comprehensively reconstruct the worms behavior as a function of only 3-4 dimensions6,7. As an example of the process we show that the worm enters and exits its reversal state in a phase specific manner. PMID:23183548

Likitlersuang, Jirapat; Stephens, Greg; Palanski, Konstantine; Ryu, William S.

2012-01-01

83

Alcohol Disinhibition of Behaviors in C. elegans  

PubMed Central

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. PMID:24681782

Topper, Stephen M.; Aguilar, Sara C.; Topper, Viktoria Y.; Elbel, Erin; Pierce-Shimomura, Jonathan T.

2014-01-01

84

Morphogenesis of the C. elegans vulva  

PubMed Central

Understanding how cells move, change shape, and alter cellular behaviors to form organs, a process termed morphogenesis, is one of the great challenges of developmental biology. Formation of the C. elegans vulva is a powerful, simple, and experimentally accessible model for elucidating how morphogenetic processes produce an organ. In the first step of vulval development, three epithelial precursor cells divide and differentiate to generate 22 cells of seven different vulval subtypes. The 22 vulval cells then rearrange from a linear array into a tube, with each of the seven cell types undergoing characteristic morphogenetic behaviours that construct the vulva. Vulval morphogenesis entails many of the same cellular activities that underlie organogenesis and tissue formation across species, including invagination, lumen formation, oriented cell divisions, cell-cell adhesion, cell migration, cell fusion, extracellular matrix remodelling and cell invasion. Studies of vulval development have led to pioneering discoveries in a number of these processes and are beginning to bridge the gap between the pathways that specify cells and their connections to morphogenetic behaviors. The simplicity of the vulva and the experimental tools available in C. elegans will continue to make vulval morphogenesis a powerful paradigm to further our understanding of the largely mysterious mechanisms that build tissues and organs. PMID:23418408

Schindler, Adam J

2012-01-01

85

Macrorestriction Analysis of Caenorhabditis Elegans Genomic DNA  

PubMed Central

The usefulness of genomic physical maps is greatly enhanced by linkage of the physical map with the genetic map. We describe a ``macrorestriction mapping'' procedure for Caenorhabditis elegans that we have applied to this endeavor. High molecular weight, genomic DNA is digested with infrequently cutting restriction enzymes and size-fractionated by pulsed field gel electrophoresis. Southern blots of the gels are probed with clones from the C. elegans physical map. This procedure allows the construction of restriction maps covering several hundred kilobases and the detection of polymorphic restriction fragments using probes that map several hundred kilobases away. We describe several applications of this technique. (1) We determined that the amount of DNA in a previously uncloned region is <220 kb. (2) We mapped the mes-1 gene to a cosmid, by detecting polymorphic restriction fragments associated with a deletion allele of the gene. The 25-kb deletion was initially detected using as a probe sequences located ~400 kb away from the gene. (3) We mapped the molecular endpoint of the deficiency hDf6, and determined that three spontaneously derived duplications in the unc-38-dpy-5 region have very complex molecular structures, containing internal rearrangements and deletions. PMID:8889524

Browning, H.; Berkowitz, L.; Madej, C.; Paulsen, J. E.; Zolan, M. E.; Strome, S.

1996-01-01

86

The twisted pharynx phenotype in C. elegans  

PubMed Central

Background The pharynx of C. elegans is an epithelial tube whose development has been compared to that of the embryonic heart and the kidney and hence serves as an interesting model for organ development. Several C. elegans mutants have been reported to exhibit a twisted pharynx phenotype but no careful studies have been made to directly address this phenomenon. In this study, the twisting mutants dig-1, mig-4, mnm-4 and unc-61 are examined in detail and the nature of the twist is investigated. Results We find that the twisting phenotype worsens throughout larval development, that in most mutants the pharynx retains its twist when dissected away from the worm body, and that double mutants between mnm-4 and mutants with thickened pharyngeal domains (pha-2 and sma-1) have less twisting in these regions. We also describe the ultrastructure of pharyngeal tendinous organs that connect the pharyngeal basal lamina to that of the body wall, and show that these are pulled into a spiral orientation by twisted pharynges. Within twisted pharynges, actin filaments also show twisting and are longer than in controls. In a mini screen of adhesionmolecule mutants, we also identified one more twisting pharynx mutant, sax-7. Conclusion Defects in pharyngeal cytoskeleton length or its anchor points to the extracellular matrix are proposed as the actual source of the twisting force. The twisted pharynx is a useful and easy-to-score phenotype for genes required in extracellular adhesion or organ attachment, and perhaps forgenes required for cytoskeleton regulation. PMID:17540043

Axäng, Claes; Rauthan, Manish; Hall, David H; Pilon, Marc

2007-01-01

87

Deciphering the Neural and Molecular Mechanisms of C. elegans Behavior  

E-print Network

for evaluating function in an intact, living animal, and in some cases have served as models for human disease [7 level. An adult C. elegans hermaphrodite contains exactly 302 neurons, comprising about a third

Schafer, William R.

88

Small RNA-mediated gene silencing pathways in C. elegans.  

PubMed

Small RNA pathways, including the RNA interference (RNAi) pathway and the microRNA (miRNA) pathway, regulate gene expression, defend against transposable elements and viruses, and, in some organisms, guide genome rearrangements. The nematode Caenorhabditis elegans (C. elegans) has been at the forefront of small RNA research; not only were the first miRNAs and their function as regulators of gene expression discovered in C. elegans, but also double-stranded RNA-induced gene silencing by RNAi was discovered in this model organism. Since then, genetic and RNAi-mediated screens, candidate gene approaches, and biochemical studies have uncovered numerous factors in the small RNA pathways and painted a rich palette of interacting pathways. Here we review the different small RNAs that have been discovered in C. elegans and discuss our understanding of their biogenesis pathways and mechanisms of action. PMID:20227516

Fischer, Sylvia E J

2010-08-01

89

Formation, regulation and evolution of Caenorhabditis elegans 3'UTRs  

E-print Network

Post-transcriptional gene regulation frequently occurs through elements in mRNA 3? untranslated regions (UTRs)1, 2. Although crucial roles for 3?UTR-mediated gene regulation have been found in Caenorhabditis elegans3, 4, ...

Jan, Calvin H.

90

A uniform genetic nomenclature for the nematode Caenorhabditis elegans  

Microsoft Academic Search

A uniform system of genetic nomenclature for the nematode Caenorhabditis elegans is described. Convenient ways are specified to designate genes, mutations and strains, and to attempt to avoid name duplications.

H. Robert Horvitz; Sydney Brenner; Jonathan Hodgkin; Robert K. Herman

1979-01-01

91

Genetic Analysis of the Vulval Cell Lineages of 'Caenorhabditis elegans'.  

National Technical Information Service (NTIS)

The cell lineages of the nematode Caenorhabditis elegans are essentially invariant among individuals. Researchers have begun an attempt to understand the genetic specification of one particular cell lineage, that of the hermaphrodite vulva. During vulval ...

E. L. Ferguson

1985-01-01

92

BACTERIAL ATTRACTION AND QUORUM SENSING INHIBITION IN CAENORHABDITIS ELEGANS EXUDATES  

PubMed Central

Caenorhabditis elegans, a bacterivorous nematode, lives in complex rotting fruit, soil, and compost environments, and chemical interactions are required for mating, monitoring population density, recognition of food, avoidance of pathogenic microbes, and other essential ecological functions. Despite being one of the best-studied model organisms in biology, relatively little is known about the signals that C. elegans uses to chemically interact with its environment or as defense. C. elegans exudates were analyzed using several analytical methods and found to contain 36 common metabolites including organic acids, amino acids and sugars, all in relatively high abundance. Furthermore, the concentrations of amino acids in the exudates were dependent on developmental stage. The C. elegans exudates were tested for bacterial chemotaxis using Pseudomonas putida (KT2440), a plant growth promoting rhizobacterium, Pseudomonas aeruginosa (PAO1), a soil bacterium pathogenic to C. elegans, and E. coli (OP50), a non-motile bacterium tested as a control. The C. elegans exudates attracted the two Psuedomonas species, but had no detectable antibacterial activity against P. aeruginosa. To our surprise, the exudates of young adult and adult life stages of C. elegans exudates inhibited quorum sensing in the reporter system based on the LuxR bacterial quorum sensing (QS) system, which regulates bacterial virulence and other factors in Vibrio fischeri. We were able to fractionate the QS inhibition and bacterial chemotaxis activities, demonstrating that these activities are chemically distinct. Our results demonstrate that C. elegans can attract its bacterial food and has the potential of partially regulating the virulence of bacterial pathogens by inhibiting specific QS systems. PMID:19649780

KAPLAN, FATMA; BADRI, DAYAKAR V.; ZACHARIAH, CHERIAN; AJREDINI, RAMADAN; SANDOVAL, FRANCISCO J; ROJE, SANJA; LEVINE, LANFANG H.; ZHANG, FENGLI; ROBINETTE, STEVEN L.; ALBORN, HANS T.; ZHAO, WEI; STADLER, MICHAEL; NIMALENDRAN, RATHIKA; DOSSEY, AARON T.; BRUSCHWEILER, RAFAEL; VIVANCO, JORGE M.; EDISON, ARTHUR S.

2014-01-01

93

Primary cutaneous zygomycosis due to Saksenaea vasiformis and Apophysomyces elegans.  

PubMed

We report three cases of primary cutaneous zygomycosis due to either Saksenaea vasiformis (two patients) or Apophysomyces elegans (one patient). Extensive surgical debridement helped two patients recover from their infections. The underlying disease in the one patient who died was diabetes mellitus. We reviewed the literature on primary cutaneous zygomycosis and found that S. vasiformis and A. elegans were the etiologic agents in 16 and 13 earlier cases, respectively. PMID:9145731

Chakrabarti, A; Kumar, P; Padhye, A A; Chatha, L; Singh, S K; Das, A; Wig, J D; Kataria, R N

1997-04-01

94

Rhino-Orbitocerebral Mucormycosis Caused by Apophysomyces elegans  

Microsoft Academic Search

Rhino-orbitocerebral mucormycosis (ROCM) caused by more common zygomycetes (e.g., Mucor) is known to cause rapidly fatal infections in immunocompromised patients. Apophysomyces elegans is an emerging zygomycete that has been reported to cause invasive cutaneous and rhino-orbitocerebral infections in immuno- competent individuals. Limited data exist describing the syndrome of ROCM caused by A. elegans. We describe a recent case and performed

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

2006-01-01

95

Apophysomyces elegans infection in a renal transplant recipient  

Microsoft Academic Search

A 50-year-old cadaveric renal transplant recipient on immunosuppressive therapy is described with post-traumatic cutaneous infection caused by Apophysomyces elegans. He showed no evidence of hematogenous dissemination and recovered fully after therapy with extensive local debridement and amphotericin B lipid complex. An apparent drug-drug interaction between amphotericin B lipid complex and cyclosporine was encountered. The course of A elegans infection in

M. Tarek Naguib; Mark M. Huycke; James A. Pederson; Larry R. Pennington; Michael E. Burton; Ronald A. Greenfield

1995-01-01

96

Identification of an estrogenic hormone receptor in Caenorhabditis elegans  

Microsoft Academic Search

Changes in both behavior and gene expression occur in Caenorhabditis elegans following exposure to sex hormones such as estrogen and progesterone, and to bisphenol A (BPA), an estrogenic endocrine-disrupting compound. However, only one steroid hormone receptor has been identified. Of the 284 known nuclear hormone receptors (NHRs) in C. elegans, we selected nhr-14, nhr-69, and nhr-121 for analysis as potential

Ai Mimoto; Madoka Fujii; Makoto Usami; Maki Shimamura; Naoko Hirabayashi; Takako Kaneko; Noboru Sasagawa; Shoichi Ishiura

2007-01-01

97

Contingency Constrained VAr Planning Using Penalty Successive Conic Programming  

Microsoft Academic Search

This paper presents a new method for VAr planning under multiple operating scenarios, optimizing sizes and locations of new reactive compensation equipment to ensure that both the system voltage profile and voltage stability requirements are met. The approach is based on ${\\\\mbi L}_{1}$-norm regularization for finding a solution with minimum VAr installation sites and on the ${\\\\mbi L}_{2}$-norm penalty function

Rabih A. Jabr; Nelson Martins; Bikash C. Pal; Sami Karaki

2012-01-01

98

The robustness of identified VAR conclusions about money  

Microsoft Academic Search

This paper presents a new way to assess robustness of claims from identified VAR work. All possible identifications are checked for the one that is worst for the claim, subject to the restriction that the VAR produce reasonable impulse responses to shocks. The statistic on which the claim is based need not be identified; thus, one can assess claims in

Jon Faust

1998-01-01

99

The nematode Caenorhabditis elegans as a model to study viruses.  

PubMed

Caenorhabditis elegans is a worm that has been extensively studied, and it is today an accepted model in many different biological fields. C. elegans is cheap to maintain, it is transparent, allowing easy localization studies, and it develops from egg to adult in around 4 days. Many mutants, available to the scientific community, have been developed. This has facilitated the study of the role of particular genes in many cellular pathways, which are highly conserved when compared with higher eukaryotes. This review describes the advantages of C. elegans as a laboratory model and the known mechanisms utilized by this worm to fight pathogens. In particular, we describe the strong C. elegans RNAi machinery, which plays an important role in the antiviral response. This has been shown in vitro (C. elegans cell cultures) as well as in vivo (RNAi-deficient strains) utilizing recently described viruses that have the worm as a host. Infections with mammalian viruses have also been achieved using chemical treatment. The role of viral genes involved in pathogenesis has been addressed by evaluating the phenotypes of transgenic strains of C. elegans expressing those genes. Very simple approaches such as feeding the worm with bacteria transformed with viral genes have also been utilized. The advantages and limitations of different approaches are discussed. PMID:25000902

Diogo, Jesica; Bratanich, Ana

2014-11-01

100

Japanese studies on neural circuits and behavior of Caenorhabditis elegans  

PubMed Central

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

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

2013-01-01

101

Oxidative stress and ageing in Caenorhabditis elegans.  

PubMed Central

Mutations in the age-1 gene double both the mean and maximum life span of Caenorhabditis elegans. They also result in an age-specific increase of catalase and Cu/Zn superoxide dismutase activity levels. The higher superoxide dismutase activity levels in age-1 mutants confer hyperresistance to the superoxide-anion-generating drug paraquat. The rate of superoxide anion production by microsome fractions declines linearly with age in age-1(+) worms, but, after an initial decline, is stabilized at a higher level in senescent age-1 mutant nematodes. These results clearly show that oxidative stress resistance and potential life span are correlated in this organism, and they suggest that the natural product of age-1 either directly or indirectly downregulates the activities of several other genes as a function of age. PMID:8389142

Vanfleteren, J R

1993-01-01

102

Ultrafast endocytosis at Caenorhabditis elegans neuromuscular junctions  

PubMed Central

Synaptic vesicles can be released at extremely high rates, which places an extraordinary demand on the recycling machinery. Previous ultrastructural studies of vesicle recycling were conducted in dissected preparations using an intense stimulation to maximize the probability of release. Here, a single light stimulus was applied to motor neurons in intact Caenorhabditis elegans nematodes expressing channelrhodopsin, and the animals rapidly frozen. We found that docked vesicles fuse along a broad active zone in response to a single stimulus, and are replenished with a time constant of about 2 s. Endocytosis occurs within 50 ms adjacent to the dense projection and after 1 s adjacent to adherens junctions. These studies suggest that synaptic vesicle endocytosis may occur on a millisecond time scale following a single physiological stimulus in the intact nervous system and is unlikely to conform to current models of endocytosis. DOI: http://dx.doi.org/10.7554/eLife.00723.001 PMID:24015355

Watanabe, Shigeki; Liu, Qiang; Davis, M Wayne; Hollopeter, Gunther; Thomas, Nikita; Jorgensen, Nels B; Jorgensen, Erik M

2013-01-01

103

Caenorhabditis elegans NPR-1–mediated behaviors are suppressed in the presence of mucoid bacteria  

E-print Network

Caenorhabditis elegans exhibits a diverse range of behaviors in response to bacteria. The presence of bacterial food influences C. elegans aerotaxis, aggregation, locomotion, and pathogen avoidance behaviors through the ...

Reddy, Kirthi C.

104

Dynamic patterning of maternal mRNAs in the Early C. elegans embryo  

E-print Network

Asymmetric segregation of maternally-encoded proteins is essential to cell fate determination during early cell divisions of the Caenorhabditis elegans (C. elegans) embryo, but little is known about the patterning of ...

Li, Jialing, Ph. D. Massachusetts Institute of Technology

2012-01-01

105

Agrobacterium tumefaciens -mediated transformation of broccoli ( Brassica oleracea var. italica ) and cabbage ( B. oleracea var. capitata )  

Microsoft Academic Search

Transgenic broccoli (Brassica oleracea var. italica) was produced by two Agrobacterium tumefaciens-mediated transformation methods. One used flowering stalk explants from mature plants; the other used hypocotyl and petiole explants from in vitro-grown seedlings. Several hundred transformants containing a Bacillus thuringiensis ?-endotoxin gene (CryIA(c)-type) and the neomycin phosphotransferase gene were recovered. Rooted transformants were obtained in as little as 3 months

Timothy D. Metz; Ram Dixit; Elizabeth D. Earle

1995-01-01

106

1D-VAR Retrieval Using Superchannels  

NASA Technical Reports Server (NTRS)

Since modern ultra-spectral remote sensors have thousands of channels, it is difficult to include all of them in a 1D-var retrieval system. We will describe a physical inversion algorithm, which includes all available channels for the atmospheric temperature, moisture, cloud, and surface parameter retrievals. Both the forward model and the inversion algorithm compress the channel radiances into super channels. These super channels are obtained by projecting the radiance spectra onto a set of pre-calculated eigenvectors. The forward model provides both super channel properties and jacobian in EOF space directly. For ultra-spectral sensors such as Infrared Atmospheric Sounding Interferometer (IASI) and the NPOESS Airborne Sounder Testbed Interferometer (NAST), a compression ratio of more than 80 can be achieved, leading to a significant reduction in computations involved in an inversion process. Results will be shown applying the algorithm to real IASI and NAST data.

Liu, Xu; Zhou, Daniel; Larar, Allen; Smith, William L.; Schluessel, Peter; Mango, Stephen; SaintGermain, Karen

2008-01-01

107

The hermaphrodite sperm oocyte switch requires the Caenorhabditis elegans homologs of PRP2 and PRP22  

E-print Network

The hermaphrodite sperm oocyte switch requires the Caenorhabditis elegans homologs of PRP2 and PRP determination in the hermaphrodite germ line of Caenorhab- ditis elegans is controlled posttranscriptionally. In Caenorhabditis elegans, the hermaphrodite produces sperm during the fourth larval stage and oocytes in the adult

Kimble, Judith

108

Cytochrome b Phylogeny Does Not Match Subspecific Classification in the Western Terrestrial Garter Snake, Thamnophis elegans  

Microsoft Academic Search

We sequenced a 307-bp fragment of the mitochondrial cytochrome b gene from 42 individuals representing 14 populations of the western terrestrial garter snake, Thamnophis elegans. Current taxonomy recognizes either five or six subspecies of T. elegans based on color and scale morphology, but all agree on three major geograph- ic races (T. e. elegans, terrestris, and vagrans). Although the cytochrome

Anne M. Bronikowski; Stevan J. Arnold; J. D. McEachran

2001-01-01

109

A genome-wide view of Caenorhabditis elegans base-substitution mutation processes  

E-print Network

nucleotides in C. elegans natural populations. A strong mutational bias from G/C to A/T nucleotides. elegans. The observed mutational bias also suggests that the C. elegans nuclear genome cannot mutation processes. high-throughput DNA sequencing mutation accumulation Mutation is the fuel for evolution

Dean, Matthew D.

110

Phytologia (December 2009) 91(3) 361 JUNIPERUS RECURVA VAR. UNCINATA, THE HOOKED  

E-print Network

Phytologia (December 2009) 91(3) 361 JUNIPERUS RECURVA VAR. UNCINATA, THE HOOKED BRANCHLET JUNIPER of sequence data from nrDNA and cpDNA (petN-psbM) of Juniperus indica, J. i. var. caespitosa, J. i. var hybridization. Phytologia 91(3): 361-382 (December, 2009). KEY WORDS: Juniperus indica, J. i. var. caespitosa, J

Adams, Robert P.

111

Caenorhabditis elegans: A Simple Nematode Infection Model for Penicillium marneffei  

PubMed Central

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. PMID:25268236

Huang, Xiaowen; Li, Dedong; Xi, Liyan; Mylonakis, Eleftherios

2014-01-01

112

Nuclear RNAi maintains heritable gene silencing in Caenorhabditis elegans  

PubMed Central

RNA interference (RNAi) is heritable in Caenorhabditis elegans; the progeny of C. elegans exposed to dsRNA inherit the ability to silence genes that were targeted by RNAi in the previous generation. Here we investigate the mechanism of RNAi inheritance in C. elegans. We show that exposure of animals to dsRNA results in the heritable expression of siRNAs and the heritable deposition of histone 3 lysine 9 methylation (H3K9me) marks in progeny. siRNAs are detectable before the appearance of H3K9me marks, suggesting that chromatin marks are not directly inherited but, rather, reestablished in inheriting progeny. Interestingly, H3K9me marks appear more prominently in inheriting progeny than in animals directly exposed to dsRNA, suggesting that germ-line transmission of silencing signals may enhance the efficiency of siRNA-directed H3K9me. Finally, we show that the nuclear RNAi (Nrde) pathway maintains heritable RNAi silencing in C. elegans. The Argonaute (Ago) NRDE-3 associates with heritable siRNAs and, acting in conjunction with the nuclear RNAi factors NRDE-1, NRDE-2, and NRDE-4, promotes siRNA expression in inheriting progeny. These results demonstrate that siRNA expression is heritable in C. elegans and define an RNAi pathway that promotes the maintenance of RNAi silencing and siRNA expression in the progeny of animals exposed to dsRNA. PMID:22106253

Burton, Nick O.; Burkhart, Kirk B.; Kennedy, Scott

2011-01-01

113

Chemically Defined Medium and Caenorhabditis elegans: A Powerful Approach  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

114

Radiation-induced genomic instability in Caenorhabditis elegans.  

PubMed

Radiation-induced genomic instability has been well documented, particularly in vitro. However, the understanding of its mechanisms and their consequences in vivo is still limited. In this study, Caenorhabditis elegans (C. elegans; strain CB665) nematodes were exposed to X-rays at doses of 0.1, 1, 3 or 10Gy. The endpoints were measured several generations after exposure and included mutations in the movement-related gene unc-58, alterations in gene expression analysed with oligoarrays containing the entire C. elegans genome, and micro-satellite mutations measured by capillary electrophoresis. The progeny of the irradiated nematodes showed an increased mutation frequency in the unc-58 gene, with a maximum response observed at 1Gy. Significant differences were also found in gene expression between the irradiated (1Gy) and non-irradiated nematode lines. Differences in gene expression did not show clear clustering into certain gene categories, suggesting that the instability might be a chaotic process rather than a result of changes in the function of few specific genes such as, e.g., those responsible for DNA repair. Increased heterogeneity in gene expression, which has previously been described in irradiated cultured human lymphocytes, was also observed in the present study in C. elegans, the coefficient of variation of gene expression being higher in the progeny of irradiated nematodes than in control nematodes. To the best of our knowledge, this is the first publication reporting radiation-induced genomic instability in C. elegans. PMID:22796420

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

2012-10-01

115

Overview of gene structure in C. elegans.  

PubMed

In the early stage of the C. elegans sequencing project, the ab initio gene prediction program Genefinder was used to find protein-coding genes. Subsequently, protein-coding genes structures have been actively curated by WormBase using evidence from all available data sources. Most coding loci were identified by the Genefinder program, but the process of gene curation results in a continual refinement of the details of gene structure, involving the correction and confirmation of intron splice sites, the addition of alternate splicing forms, the merging and splitting of incorrect predictions, and the creation and extension of 5' and 3' ends. The development of new technologies results in the availability of further data sources, and these are incorporated into the evidence used to support the curated structures. Non-coding genes are more difficult to curate using this methodology, and so the structures for most of these have been imported from the literature or from specialist databases of ncRNA data. This article describes the structure and curation of transcribed regions of genes. PMID:25368915

Spieth, John; Lawson, Daniel; Davis, Paul; Williams, Gary; Howe, Kevin

2014-01-01

116

Locomotion of C elegans in structured environments  

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

117

Long noncoding RNAs in C. elegans  

PubMed Central

Thousands of long noncoding RNAs (lncRNAs) have been found in vertebrate animals, a few of which have known biological roles. To better understand the genomics and features of lncRNAs in invertebrates, we used available RNA-seq, poly(A)-site, and ribosome-mapping data to identify lncRNAs of Caenorhabditis elegans. We found 170 long intervening ncRNAs (lincRNAs), which had single- or multiexonic structures that did not overlap protein-coding transcripts, and about sixty antisense lncRNAs (ancRNAs), which were complementary to protein-coding transcripts. Compared to protein-coding genes, the lncRNA genes tended to be expressed in a stage-dependent manner. Approximately 25% of the newly identified lincRNAs showed little signal for sequence conservation and mapped antisense to clusters of endogenous siRNAs, as would be expected if they serve as templates and targets for these siRNAs. The other 75% tended to be more conserved and included lincRNAs with intriguing expression and sequence features associating them with processes such as dauer formation, male identity, sperm formation, and interaction with sperm-specific mRNAs. Our study provides a glimpse into the lncRNA content of a nonvertebrate animal and a resource for future studies of lncRNA function. PMID:22707570

Nam, Jin-Wu; Bartel, David P.

2012-01-01

118

ASI regulates satiety quiescence in C. elegans  

PubMed Central

In C. elegans, satiety quiescence mimics behavioral aspects of satiety and post-prandial 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 TGF? pathway, whose ligand is released from ASI, regulates satiety quiescence. The mutants of a ligand, a receptor and SMADs in the TGF? pathway all eat more and show less quiescence than wild type. The TGF? 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 TGF? 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 TGF? and cGMP pathways in ASI connect nutritional status to promotion of satiety quiescence, a sleep-like behavioral state. PMID:23739968

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

2013-01-01

119

New phenylpropanoid glycosides from Juniperus communis var. depressa.  

PubMed

Two new phenylpropanoid glycosides were isolated from the leaves and stems of Juniperus communis var. depressa (Cupressaceae) along with 14 known compounds. Their structures were determined by spectral analyses, in particular by 2D-NMR spectral evidence. PMID:20460808

Iida, Naoki; Inatomi, Yuka; Murata, Hiroko; Murata, Jin; Lang, Frank A; Tanaka, Toshiyuki; Nakanishi, Tsutomu; Inada, Akira

2010-05-01

120

Coordination of behavioral hierarchies during environmental transitions in Caenorhabditis elegans  

PubMed Central

For animals inhabiting multiple environments, the ability to select appropriate behaviors is crucial as their adaptability is often context dependent. Caenorhabditis elegans uses distinct gaits to move on land and in water. Gait transitions can potentially coordinate behaviors associated with distinct environments. We investigated whether land and water differentially affect the behavioral repertoire of C. elegans. Swimming worms interrupted foraging, feeding, egg-laying and defecation. Exogenous dopamine induced bouts of these land-associated behaviors in water. Our finding that worms do not drink fluid while immersed may explain why higher drug doses are required in water than on land to elicit the same effects. C. elegans is a valid model to study behavioral hierarchies and how environmental pressures alter their balance. PMID:23525841

Vidal-Gadea, Andres G.; Davis, Scott; Becker, Lindsay; Pierce-Shimomura, Jonathan T.

2012-01-01

121

Catabolic pathways of glucose in Bacillus circulans var. alkalophilus  

Microsoft Academic Search

Enzymes and the metabolic pathways of glucose catabolism of Bacillus circulans var. alkalophilus were studied. The metabolism of the microbe was mixed acid fermentative yielding mainly acetic and formic acids as end products\\u000a from glucose. It was estimated that B. circulans var. alkalophilus partitions 90%–93% of the carbon from glucose into the Embden-Meyerhof-Parnas (EMP) pathway and 7%–10% into the hexose

Sari Paavilainen; Soili Oinonen; Timo Korpela

1999-01-01

122

Phycoerythrin extends life span and health span of Caenorhabditis elegans.  

PubMed

In the present study, we tested the antioxidant activity of phycoerythrin (PE, an oligomeric light harvesting protein isolated from Lyngbya sp. A09DM) to curtail aging effects in Caenorhabditis elegans. Purified PE (100 ?g/ml) dietary supplement was given to C. elegans and investigated for its anti-aging potential. PE treatment improved the mean life span of wild type (N2)-animals from 15?±?0.1 to 19.9?±?0.3 days. PE treatment also moderated the decline in aging-associated physiological functions like pharyngeal pumping and locomotion with increasing age of N2 worms. Moreover, PE treatment also enhanced the stress tolerance in 5-day-aged adults with increase in mean survival rate from 22.2?±?2.5 to 41.6?±?2.5 % under thermo stress and from 30.1?±?3.2 to 63.1?±?6.4 % under oxidative (hydrogen peroxide)-stress. PE treatment was also noted to moderate the heat-induced expression of human amyloid-beta(A?1-42) peptide and associated paralysis in the muscle tissues of transgenic C. elegans CL4176 (Alzheimer's disease model). Effectiveness of PE in expanding the life span of mutant C. elegans, knockout for some up (daf-2 and age-1)- and down (daf-16)-stream regulators of insulin/IGF-1 signaling (IIS), shows the independency of PE effect from DAF-2-AGE-1-DAF-16 signaling pathway. Moreover, the inability of PE in expanding the life span of hsf-1 knockout C. elegans(sy441) suggests the dependency of PE effect on heat shock transcription factor (HSF-1) controlling stress-induced gene expression. In conclusion, our results demonstrated a novel anti-aging activity of PE which conferred increased resistance to cellular stress resulting in improved life span and health span of C. elegans. PMID:25304463

Sonani, Ravi Raghav; Singh, Niraj Kumar; Awasthi, Anjali; Prasad, Birendra; Kumar, Jitendra; Madamwar, Datta

2014-10-01

123

Rhino-Orbitocerebral Mucormycosis Caused by Apophysomyces elegans  

PubMed Central

Rhino-orbitocerebral mucormycosis (ROCM) caused by more common zygomycetes (e.g., Mucor) is known to cause rapidly fatal infections in immunocompromised patients. Apophysomyces elegans is an emerging zygomycete that has been reported to cause invasive cutaneous and rhino-orbitocerebral infections in immunocompetent individuals. Limited data exist describing the syndrome of ROCM caused by A. elegans. We describe a recent case and performed a comprehensive literature review to delineate the clinical characteristics of ROCM caused by A. elegans. Our case is a 50-year-old man with diabetes mellitus who presented with facial pain and right eye proptosis. Endoscopic sinus sampling revealed A. elegans. He was treated with liposomal amphotericin B and multiple debridements, with no disease on 1.5-year follow-up examination. Seven cases were identified on literature review, including the present case. Most patients (86%) were male, with a mean age of 40 years. Most patients (71%) did not have predisposing medical conditions. Three patients had predisposing head trauma. All presented with facial and/or periorbital pain. All had magnetic resonance imaging or computed tomography of the head showing intraorbital and/or sinus inflammation. Diagnosis was confirmed by histopathology and deep tissue culture in all cases. All patients required eye exenteration and extensive surgical debridement, in addition to intravenous amphotericin B. Six of the seven patients (86%) recovered. ROCM caused by A. elegans is rarely reported in the literature. Most such infections occurred in immunocompetent patients, often after facial trauma. Survival in ROCM caused by A. elegans is favorable in reported cases, with prompt surgical debridement and antifungal therapy. PMID:16517873

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

2006-01-01

124

Rhino-orbitocerebral mucormycosis caused by Apophysomyces elegans.  

PubMed

Rhino-orbitocerebral mucormycosis (ROCM) caused by more common zygomycetes (e.g., Mucor) is known to cause rapidly fatal infections in immunocompromised patients. Apophysomyces elegans is an emerging zygomycete that has been reported to cause invasive cutaneous and rhino-orbitocerebral infections in immunocompetent individuals. Limited data exist describing the syndrome of ROCM caused by A. elegans. We describe a recent case and performed a comprehensive literature review to delineate the clinical characteristics of ROCM caused by A. elegans. Our case is a 50-year-old man with diabetes mellitus who presented with facial pain and right eye proptosis. Endoscopic sinus sampling revealed A. elegans. He was treated with liposomal amphotericin B and multiple debridements, with no disease on 1.5-year follow-up examination. Seven cases were identified on literature review, including the present case. Most patients (86%) were male, with a mean age of 40 years. Most patients (71%) did not have predisposing medical conditions. Three patients had predisposing head trauma. All presented with facial and/or periorbital pain. All had magnetic resonance imaging or computed tomography of the head showing intraorbital and/or sinus inflammation. Diagnosis was confirmed by histopathology and deep tissue culture in all cases. All patients required eye exenteration and extensive surgical debridement, in addition to intravenous amphotericin B. Six of the seven patients (86%) recovered. ROCM caused by A. elegans is rarely reported in the literature. Most such infections occurred in immunocompetent patients, often after facial trauma. Survival in ROCM caused by A. elegans is favorable in reported cases, with prompt surgical debridement and antifungal therapy. PMID:16517873

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

2006-03-01

125

Plasmodium falciparum: epigenetic control of var gene regulation and disease.  

PubMed

Plasmodium falciparum, one of the deadliest parasites on earth causes human malaria resulting one million deaths annually. Central to the parasite pathogenicity and morbidity is the switching of parasite virulence (var) gene expression causing host immune evasion. The regulation of Plasmodium var gene expression is poorly understood. The complex life cycle of Plasmodium and mutually exclusive expression pattern of var genes make this disease difficult to control. Recent studies have demonstrated the pivotal role of epigenetic mechanism for control of coordinated expression of var genes, important for various clinical manifestations of malaria. In this review, we discuss about different Plasmodium histones and their various modifications important for gene expression and gene repression.Contribution of epigenetic mechanism to understand the var gene expression is also highlighted. We also describe in details P. falciparum nuclear architecture including heterochromatin, euchromatin and telomeric regions and their importance in subtelomeric and centrally located var gene expression. Finally, we explore the possibility of using Histone Acetyl Transferase (HAT) and Histone Deacetylase (HDAC)inhibitors against multi-drug resistance malaria parasites to provide another line of treatment for malaria. PMID:23150271

Deshmukh, Abhijit S; Srivastava, Sandeep; Dhar, Suman Kumar

2013-01-01

126

Proteomic Study and Marker Protein Identification of Caenorhabditis elegans Lipid Droplets*  

PubMed Central

Lipid droplets (LDs) are a neutral lipid storage organelle that is conserved across almost all species. Many metabolic syndromes are directly linked to the over-storage of neutral lipids in LDs. The study of LDs in Caenorhabditis elegans (C. elegans) has been difficult because of the lack of specific LD marker proteins. Here we report the purification and proteomic analysis of C. elegans lipid droplets for the first time. We identified 306 proteins, 63% of these proteins were previously known to be LD-proteins, suggesting a similarity between mammalian and C. elegans LDs. Using morphological and biochemical analyses, we show that short-chain dehydrogenase, DHS-3 is almost exclusively localized on C. elegans LDs, indicating that it can be used as a LD marker protein in C. elegans. These results will facilitate further mechanistic studies of LDs in this powerful genetic system, C. elegans. PMID:22493183

Zhang, Peng; Na, Huimin; Liu, Zhenglong; Zhang, Shuyan; Xue, Peng; Chen, Yong; Pu, Jing; Peng, Gong; Huang, Xun; Yang, Fuquan; Xie, Zhensheng; Xu, Tao; Xu, Pingyong; Ou, Guangshuo; Zhang, Shaobing O.; Liu, Pingsheng

2012-01-01

127

An integrated theory of ageing in the nematode Caenorhabditis elegans  

PubMed Central

Numerous theories of ageing have been proposed, and many have been tested experimentally, particularly using nematode models such as Caenorhabditis elegans. By combining those theories of ageing that remain plausible with recent findings from studies of C. elegans life span mutants, an integrated theory of ageing has been devised. This is formed from 3 interconnected elements: the evolutionary theory of ageing, the oxidative damage theory of ageing, and a nonadaptive programmed ageing theory. This tripartite theory of ageing gives rise to a number of predictions that may be tested experimentally. PMID:11197524

GEMS, DAVID

2000-01-01

128

Mechanism and regulation of translation in C. elegans.  

PubMed

C. elegans represents a favorable system to study the extraordinarily complicated process of eukaryotic protein synthesis, which involves over 100 RNAs and over 200 polypeptides just for the core machinery. Initial research in protein synthesis relied on fractionated mammalian and plant systems, but in the mid-1970s, the powerful genetics of Saccharomyces cerevisiae began to yield new insights for translation in all eukaryotes. C. elegans has many features of higher eukaryotes that are not shared by yeast. This allows protein synthesis researchers to combine biochemistry, cell biology, developmental biology, genetics, and genomics to study regulation of gene expression at the translational level. Most components of the core translational machinery have been identified in C. elegans, including rRNAs, 5S RNA, tRNAs, ribosomal proteins, and aminoacyl tRNA synthetases. C. elegans has amino acid sequence homologs for 56 of the known initiation, elongation, and release factor polypeptides, but few of these have been isolated, functionally identified, or studied at the biochemical level. Similarly, C. elegans has homologs for 22 components of the major signal transduction pathways implicated in control of protein synthesis. The translational efficiency of individual mRNAs relies on cis-regulatory elements that include either a 7-methylguanosine- or 2,2,7-trimethylguanosine-containing cap, the 5'-terminal spliced leader, sequence elements in the 3'-untranslated regions, and the 3'-terminal poly(A) tract. Several key developmental pathways in C. elegans are predominantly governed by translational mechanisms. Some evidence has been presented that well described regulatory mechanisms in other organisms, including covalent modification of translation factors, sequestration of translation factors, and mRNA-specific changes in poly(A) length, also occur in C. elegans. The most interesting unexplored questions may involve changes in the translation of individual mRNAs during development, in response to physiological changes, or after genetic manipulations. Given the highly developed state of C. elegans genomics, it can be expected that future application of computational tools, including data visualization, will help detect new instances of translational control. PMID:18050488

Rhoads, Robert E; Dinkova, Tzvetanka D; Korneeva, Nadejda L

2006-01-01

129

Imaging Lipid Metabolism in Live Caenorhabditis elegans Using Fingerprint Vibrations.  

PubMed

Quantitation of lipid storage, unsaturation, and oxidation in live C.?elegans has been a long-standing obstacle. The combination of hyperspectral stimulated Raman scattering imaging and multivariate analysis in the fingerprint vibration region represents a platform that allows the quantitative mapping of fat distribution, degree of fat unsaturation, lipid oxidation, and cholesterol storage in?vivo in the whole worm. Our results reveal for the first time that lysosome-related organelles in intestinal cells are sites for storage of cholesterol in C.?elegans. PMID:25195517

Wang, Ping; Liu, Bin; Zhang, Delong; Belew, Micah Y; Tissenbaum, Heidi A; Cheng, Ji-Xin

2014-10-27

130

Sperm and Oocyte Communication Mechanisms Controlling C. elegans Fertility  

PubMed Central

During sexual reproduction in many species, sperm and oocyte secrete diffusible signaling molecules to help orchestrate the biological symphony of fertilization. In the Caenorhabditis elegans gonad, bidirectional signaling between sperm and oocyte is important for guiding sperm to the fertilization site and inducing oocyte maturation. The molecular mechanisms that regulate sperm guidance and oocyte maturation are being delineated. Unexpectedly, these mechanisms are providing insight into human diseases, such as amyotrophic lateral sclerosis, spinal muscular atrophy, and cancer. Here we review sperm and oocyte communication in C. elegans and discuss relationships to human disorders. PMID:20034089

Han, Sung Min; Cottee, Pauline A.; Miller, Michael A.

2010-01-01

131

Systemic Apophysomyces elegans after trauma: case report and literature review.  

PubMed

We present a case of systemic fungal infection caused by Apophysomyces elegans in a 50-year-old patient who developed a progressive skin lesion after a motor vehicle crash. Histopathological and mycological examination of the surgical sample showed non-septated hyphae characteristic of mucoraceous fungi. Despite extensive surgical debridement, and parenteral administration of amphotericin B, the patient died of multi-organ failure. Autopsy findings suggested systemic involvement. The fungi recovered from culture had non-apophyseal and globose sporangi, and branched sporaniophores and was identified as Apophysomyces elegans. PMID:12542929

Wang, Jue; Harvey, Charles M; Calhoun, Jason H; Yin, Li-Yan; Mader, Jon T

2002-01-01

132

Invasive infection due to Apophysomyces elegans in immunocompetent hosts.  

PubMed

A previously well 59-year-old man developed necrotizing, invasive cellulitis and subsequent osteomyelitis at what was judged to be the site of a bite or sting. The pathogen isolated was Apophysomyces elegans. Eventually, in addition to treatment with intravenous amphotericin B, en bloc resection was required for cure. Only six previous cases of A. elegans infection have been reported in the literature. The lack of underlying disease in six of the total of seven cases contrasts with the usual findings for other zygomycoses. This article describes all seven reported cases as well as the characteristics of this unique fungal pathogen. PMID:8286630

Weinberg, W G; Wade, B H; Cierny, G; Stacy, D; Rinaldi, M G

1993-11-01

133

The role of Erwinia carotovora in the epidemiology of potato blackleg I. Relationship of E. carotorora var. carotovora and E. carotovora var. atroseptica to potato blackleg in Colorado  

Microsoft Academic Search

Isolations from 315 blackleg infected potato stems collected over a two year period in Colorado, demonstrated that both varieties\\u000a ofErwinia carotovora, E. carotovora var.carotovora andE. carotovora var.atroseptica, are involved in stem infections under field conditions.E. carotovora var.atroseptica was the predominant organism associated with stem infections in all areas sampled.E. carotovora var.carotovora was isolated, with few exceptions, only from plants collected

J. J. Molina; M. D. Harrison

1977-01-01

134

Comparative Developmental Expression Profiling of Two C. elegans Isolates  

Microsoft Academic Search

Gene expression is known to change during development and to vary among genetically diverse strains. Previous studies of temporal patterns of gene expression during C. elegans development were incomplete, and little is known about how these patterns change as a function of genetic background. We used microarrays that comprehensively cover known and predicted worm genes to compare the landscape of

Emily J. Capra; Sonja M. Skrovanek; Leonid Kruglyak; Xiaolin Wu

2008-01-01

135

FROM GENES TO FUNCTION : THE C. ELEGANS GENETIC TOOLBOX  

PubMed Central

This review aims to provide an overview of the technologies which make the nematode Caenorhabditis elegans an attractive genetic model system. We describe transgenesis techniques and forward and reverse genetic approaches to isolate mutants and clone genes. In addition, we discuss the new possibilities offered by genome engineering strategies and next generation genome analysis tools. PMID:23801671

BOULIN, Thomas; HOBERT, Oliver

2013-01-01

136

Analysis of Wnt Signaling During Caenorhabditis elegans Postembryonic Development  

E-print Network

," allowing -catenin to translocate to the nucleus where it complexes with TCF/LEF family members to activate rather easy. In order to design a genetic screen to isolate genetic mutations that affect a specific. elegans screens begin with a population of wild-type hermaphrodites exposed to ethyl methane sulphonate

Kaufman, Glennis A.

137

Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans  

PubMed Central

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

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

2013-01-01

138

Real-time Embryogenesis in Live Caenorhabditis elegans Worms  

NSDL National Science Digital Library

This is a lab exercise geared toward first-year undergraduate biology majors, where they get to view early embryogenesis in a live animal. In this exercise students will prepare slides if live C. elegans embryos, find one- or two-cell stage embryos, and observe cleavage stage of embryogenesis over the course of 30 minutes.

Dr. Anita G Fernandez (Fairfield University Biology); Ian Chin-Sing (Queens University)

2011-11-21

139

Toxicological Effects of Cerium Oxide Nanoparticle Aggregates on Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

Assessing the toxicity and unique reactivity of nanoparticles in biological systems has become an relevant and quickly growing area of environmental toxicology research. The broad use of nanoparticles in industrial and commercial commodities results in exposure of these nano-compounds to the environment, the ecosystems, and humans. While previous data has suggested that cerium oxide (CeO 2) nanoparticles are relatively safe to cultured cells much less is known about the potential toxicity of these materials at the organismal level. In this study we employed transgenic Caenorhabditis elegans (C. elegans) strains to assess the toxicity of CeO2 nanoparticles under "real-world" conditions. Our findings indicate that while exposure to aggregated CeO2 in C. elegans has no effect on average life span, it is associated with decreases in nematode body length, progeny count, and increased organismal stress. These findings demonstrate that exposure to aggregated CeO2 particles (0-17.21 ug/mL) may be associated with diminished organismal fitness in C. elegans..

Rebola, Alejandro Federico

140

THE GENETICS OF LEVAMISOLE RESISTANCE IN THE NEMATODE CAENORHABDITIS ELEGANS  

Microsoft Academic Search

We have characterized a small group of genes (13 loci) in the nematode Caenorhabditis elegans that, when mutated, confer resistance to the potent anthelmintic levamisole. Mutants at the 7 loci conferring the most extreme resistance generally possess almost identical visible and pharmacological phenotypes: uncoordinated motor behavior, most severe in early larval life, extreme resistance to cholinergic agonists and sensitivity to

JAMES A. LEWIS; C.-H. WU; HOWARD BERG; JOSEPH H. LEVINE

1980-01-01

141

A method for culturing embryonic C. elegans cells.  

PubMed

C. elegans is a powerful model system, in which genetic and molecular techniques are easily applicable. Until recently though, techniques that require direct access to cells and isolation of specific cell types, could not be applied in C. elegans. This limitation was due to the fact that tissues are confined within a pressurized cuticle which is not easily digested by treatment with enzymes and/or detergents. Based on early pioneer work by Laird Bloom, Christensen and colleagues developed a robust method for culturing C. elegans embryonic cells in large scale. Eggs are isolated from gravid adults by treatment with bleach/NaOH and subsequently treated with chitinase to remove the eggshells. Embryonic cells are then dissociated by manual pipetting and plated onto substrate-covered glass in serum-enriched media. Within 24 hr of isolation cells begin to differentiate by changing morphology and by expressing cell specific markers. C. elegans cells cultured using this method survive for up 2 weeks in vitro and have been used for electrophysiological, immunochemical, and imaging analyses as well as they have been sorted and used for microarray profiling. PMID:24084243

Sangaletti, Rachele; Bianchi, Laura

2013-01-01

142

Involvement of AAT transporters in methylmercury toxicity in Caenorhabditis elegans  

PubMed Central

Methylmercury (MeHg) is a potent neurotoxin that enters mammalian cells as a conjugate with L-cysteine through L-type large neutral amino acid transporter, LAT1, by a molecular mimicry mechanism by structurally resembling L-methionine. Caenorhabditis elegans (C. elegans) has been increasingly used to study the neurotoxic effects of MeHg, but little is known about uptake and transport of MeHg in the worm. This study examined whether MeHg uptake through LAT1 is evolutionarily conserved in nematodes. MeHg toxicity in C. elegans was blocked by pre-treatment of worms with L-methionine, suggesting a role for amino acid transporters in MeHg transport. Knockdown of aat-1, aat-2, and aat-3, worm homologues to LAT1, increased the survival of C. elegans following MeHg treatment and significantly attenuated MeHg content following exposure. These results indicate that MeHg is transported in the worm by a conserved mechanism dependent on functioning amino acid transporters. PMID:23669041

Caito, Samuel W.; Zhang, Yaofang; Aschner, Michael

2013-01-01

143

Cell Host & Microbe Antifungal Innate Immunity in C. elegans  

E-print Network

pathogen is nlp-29, encoding an antimicrobial peptide. In a screen for mutants that fail to express nlp-29 pathway to regulate nlp-29. This involves G protein signaling and specific C-type phospholi- pases acting, but another C. elegans PKC gene, pkc-3, functions nonredundantly with tpa-1 to control nlp-29 expression

Ewbank, Jonathan

144

Noncanonical cell death programs in the nematode Caenorhabditis elegans  

E-print Network

Review Noncanonical cell death programs in the nematode Caenorhabditis elegans ES Blum1 , M (caspase), which function in a linear pathway to promote developmental cell death in this organism. While this core pathway functions in many cells, recent studies suggest that additional regulators, acting

Shaham, Shai

145

Uncoupling of Longevity and Telomere Length in C. elegans  

Microsoft Academic Search

The nematode Caenorhabditis elegans, after completing its developmental stages and a brief reproductive period, spends the remainder of its adult life as an organism consisting exclusively of post-mitotic cells. Here we show that telomere length varies considerably in clonal populations of wild-type worms, and that these length differences are conserved over at least ten generations, suggesting a length regulation mechanism

Marcela Raices; Hugo Maruyama; Andrew Dillin; Jan Karlseder

2005-01-01

146

C. elegans as a premier longevity and aging model  

E-print Network

the worm a model for late-onset diseases such as Alzheimer's disease and Huntington's dis- ease (Link, 1995-wide changes associ- ated with disease. By contrast, C. elegans lives for only 2-3 weeks and is easily prop pathways and age-related diseases in mammals. Insulin/IGF-1 signaling Over 20 years ago it was discovered

Murphy, Coleen

147

Standard Osmium/Gluteraldehyde fixationa for C. elegans  

E-print Network

Standard Osmium/Gluteraldehyde fixationa for C. elegans Sandhya Koushika and Michael Nonet b in the osmium waste container in the hood. 5. Transfer the worms to an iced glass dissecting platform.4). Filter. Fix A: 0.67% gluteraldehyde/0.67% Osmium in 10mM HEPES (53.6 µl 25% Gluteraldehyde

Bridgman, Paul C.

148

Pharmacology of delayed aging and extended lifespan of Caenorhabditis elegans  

E-print Network

; accepted 12 June 2006 Available online 26 July 2006 Abstract The identification and analysis of compounds Caenorhabditis elegans to identify and characterize compounds that delay aging and extend lifespan. These studies compounds with antioxidant activities including vitamin E, tocotrienols, coenzyme Q, and Eukarion-8/134. (2

Kornfeld, S. Kerry

149

Metabolism of quercetin by Cunninghamella elegans ATCC 9245.  

PubMed

Incubation of quercetin with Cunninghamella elegans ATCC 9245 yielded three metabolites, including quercetin 3-O-?-D-glucopyranoside, kaempferol 3-O-?-D-glucopyranoside and isorhamnetin 3-O-?-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. PMID:21742550

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

2011-10-01

150

Caenorhabditis elegans: An Emerging Model in Biomedical and Environmental Toxicology  

Microsoft Academic Search

The nematode Caenorhabditis elegans has emerged as an important animal model in various fields including neurobiology, developmental biology, and genetics. Characteristics of this animal model that have contributed to its success include its genetic manipulability, invariant and fully described developmen- tal program, well-characterized genome, ease of maintenance, short and prolific life cycle, and small body size. These same features have

Maxwell C. K. Leung; Phillip L. Williams; Alexandre Benedetto; Catherine Au; Kirsten J. Helmcke; Michael Aschner; Joel N. Meyer

2008-01-01

151

Caenorhabditis elegans pathways that surveil and defend mitochondria  

PubMed Central

Mitochondrial function is challenged by toxic byproducts of metabolism as well as by pathogen attack1,2. Caenorhabditis elegans normally responds to mitochondrial dysfunction with activation of mitochondrial repair, drug detoxification, and pathogen-response pathways1–7. From a genome-wide RNAi screen, we identified 45 C. elegans genes that are required to upregulate detoxification, pathogen-response, and mitochondrial repair pathways after inhibition of mitochondrial function by drugs or genetic disruption. Animals defective in ceramide biosynthesis are deficient in mitochondrial surveillance, and addition of particular ceramides can rescue the surveillance defects. Ceramide can also rescue the mitochondrial surveillance defects of other gene inactivations, mapping these gene activities upstream of ceramide. Inhibition of the mevalonate pathway, either by RNAi or statin drugs also disrupts mitochondrial surveillance. Growth of C. elegans with a significant fraction of bacterial species from their natural habitat causes mitochondrial dysfunction. Other bacterial species inhibit C. elegans defense responses to a mitochondrial toxin, revealing bacterial countermeasures to animal defense. PMID:24695221

Liu, Ying; Samuel, Buck S.; Breen, Peter C.; Ruvkun, Gary

2014-01-01

152

Automated microfluidic compact disc (CD) cultivation system of Caenorhabditis elegans  

Microsoft Academic Search

Microfabricated platforms for automated cultivation and behavioral observation of animals would be a valuable tool in physiological and genetic studies. We report an automated microfluidic compact disc (CD) system specialized for cultivating and monitoring Caenorhabditis elegans, proficient in automated feeding, waste removal and live-animal microscopy. The automated CD cultivation platform contains cultivation, nutrient, and waste chamber, channels connecting the chambers,

Nahui Kim; Catherine M. Dempsey; Jim V. Zoval; Ji-Ying Sze; Marc J. Madou

2007-01-01

153

Osteomyelitis of the sternum caused by Apophysomyces elegans.  

PubMed

Apophysomyces elegans, a member of the family Mucoraceae, was found to infect the chest wall and sternum of an immunocompetent man following minor trauma. As in previous cases, amphotericin B therapy alone was inadequate. Extensive surgical debridement was required in order to eradicate the infection. PMID:7852578

Eaton, M E; Padhye, A A; Schwartz, D A; Steinberg, J P

1994-11-01

154

Emerging zygomycoses of humans: Saksenaea vasiformis and Apophysomyces elegans.  

PubMed

Since the first isolation of Saksenaea vasiformis and Apophysomyces elegans from soil specimens in 1953 and 1979, respectively, more than 30 human infections have occurred with these organisms. This paper will review the laboratory diagnosis and clinical manifestations of infections with these emerging zygomycetes. PMID:9504064

Holland, J

1997-12-01

155

Osteomyelitis of the sternum caused by Apophysomyces elegans.  

PubMed Central

Apophysomyces elegans, a member of the family Mucoraceae, was found to infect the chest wall and sternum of an immunocompetent man following minor trauma. As in previous cases, amphotericin B therapy alone was inadequate. Extensive surgical debridement was required in order to eradicate the infection. Images PMID:7852578

Eaton, M E; Padhye, A A; Schwartz, D A; Steinberg, J P

1994-01-01

156

The Perfect C. elegans Project: An Initial Report Hiroaki Kitano  

E-print Network

identification of cell lineage of the worm [Sulston and Horvitz, 77, Kimble and Hirsh, 79, Sulston et al., 83 of the components and their isolated functions do not lead to an understanding of the dynamics behind the global on earth. It has a life span of about 3 days and feeds on bacteria. C. elegans has no female sex (only

Luke, Sean

157

Whole-genome sequencing and variant discovery in C. elegans  

Microsoft Academic Search

Massively parallel sequencing instruments enable rapid and inexpensive DNA sequence data production. Because these instruments are new, their data require characterization with respect to accuracy and utility. To address this, we sequenced a Caernohabditis elegans N2 Bristol strain isolate using the Solexa Sequence Analyzer, and compared the reads to the reference genome to characterize the data and to evaluate coverage

LaDeana W Hillier; Gabor T Marth; Aaron R Quinlan; David Dooling; Ginger Fewell; Derek Barnett; Paul Fox; Jarret I Glasscock; Matthew Hickenbotham; Weichun Huang; Vincent J Magrini; Ryan J Richt; Sacha N Sander; Donald A Stewart; Michael Stromberg; Eric F Tsung; Todd Wylie; Tim Schedl; Richard K Wilson; Elaine R Mardis

2008-01-01

158

Antifungal Chemical Compounds Identified Using a C. elegans Pathogenicity Assay  

E-print Network

of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida of the main obstacles in current antifungal discovery. Here, we show that Candida albicans, as well as other. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament

Ausubel, Frederick M.

159

The C. elegans Rab Family: Identification, Classification and Toolkit Construction  

PubMed Central

Rab monomeric GTPases regulate specific aspects of vesicle transport in eukaryotes including coat recruitment, uncoating, fission, motility, target selection and fusion. Moreover, individual Rab proteins function at specific sites within the cell, for example the ER, golgi and early endosome. Importantly, the localization and function of individual Rab subfamily members are often conserved underscoring the significant contributions that model organisms such as Caenorhabditis elegans can make towards a better understanding of human disease caused by Rab and vesicle trafficking malfunction. With this in mind, a bioinformatics approach was first taken to identify and classify the complete C. elegans Rab family placing individual Rabs into specific subfamilies based on molecular phylogenetics. For genes that were difficult to classify by sequence similarity alone, we did a comparative analysis of intron position among specific subfamilies from yeast to humans. This two-pronged approach allowed the classification of 30 out of 31 C. elegans Rab proteins identified here including Rab31/Rab50, a likely member of the last eukaryotic common ancestor (LECA). Second, a molecular toolset was created to facilitate research on biological processes that involve Rab proteins. Specifically, we used Gateway-compatible C. elegans ORFeome clones as starting material to create 44 full-length, sequence-verified, dominant-negative (DN) and constitutive active (CA) rab open reading frames (ORFs). Development of this toolset provided independent research projects for students enrolled in a research-based molecular techniques course at California State University, East Bay (CSUEB). PMID:23185324

Gallegos, Maria E.; Balakrishnan, Sanjeev; Chandramouli, Priya

2012-01-01

160

TILLING is an effective reverse genetics technique for Caenorhabditis elegans  

Microsoft Academic Search

BACKGROUND: TILLING (Targeting Induced Local Lesions in Genomes) is a reverse genetic technique based on the use of a mismatch-specific enzyme that identifies mutations in a target gene through heteroduplex analysis. We tested this technique in Caenorhabditis elegans, a model organism in which genomics tools have been well developed, but limitations in reverse genetics have restricted the number of heritable

Erin J Gilchrist; Nigel J O'Neil; Ann M Rose; Monique C Zetka; George W Haughn

2006-01-01

161

Histidine Protects Against Zinc and Nickel Toxicity in Caenorhabditis elegans  

PubMed Central

Zinc is an essential trace element involved in a wide range of biological processes and human diseases. Zinc excess is deleterious, and animals require mechanisms to protect against zinc toxicity. To identify genes that modulate zinc tolerance, we performed a forward genetic screen for Caenorhabditis elegans mutants that were resistant to zinc toxicity. Here we demonstrate that mutations of the C. elegans histidine ammonia lyase (haly-1) gene promote zinc tolerance. C. elegans haly-1 encodes a protein that is homologous to vertebrate HAL, an enzyme that converts histidine to urocanic acid. haly-1 mutant animals displayed elevated levels of histidine, indicating that C. elegans HALY-1 protein is an enzyme involved in histidine catabolism. These results suggest the model that elevated histidine chelates zinc and thereby reduces zinc toxicity. Supporting this hypothesis, we demonstrated that dietary histidine promotes zinc tolerance. Nickel is another metal that binds histidine with high affinity. We demonstrated that haly-1 mutant animals are resistant to nickel toxicity and dietary histidine promotes nickel tolerance in wild-type animals. These studies identify a novel role for haly-1 and histidine in zinc metabolism and may be relevant for other animals. PMID:21455490

Murphy, John T.; Bruinsma, Janelle J.; Schneider, Daniel L.; Collier, Sara; Guthrie, James; Chinwalla, Asif; Robertson, J. David; Mardis, Elaine R.; Kornfeld, Kerry

2011-01-01

162

Timing of Locomotor Activity Circadian Rhythms in Caenorhabditis elegans  

PubMed Central

Circadian rhythms are driven by endogenous biological clocks and are synchronized to environmental cues. The chronobiological study of Caenorhabditis elegans, an extensively used animal model for developmental and genetic research, might provide fundamental information about the basis of circadian rhythmicity in eukaryotes, due to its ease of use and manipulations, as well as availability of genetic data and mutant strains. The aim of this study is to fully characterize the circadian rhythm of locomotor activity in C. elegans, as well as a means for genetic screening in this nematode and the identification of circadian mutants. We have developed an infrared method to measure locomotor activity in C. elegans and found that, under constant conditions, although inter-individual variability is present, circadian periodicity shows a population distribution of periods centered at 23.9±0.4 h and is temperature-compensated. Locomotor activity is entrainable by light-dark cycles and by low-amplitude temperature cycles, peaking around the night-day transition and day, respectively. In addition, lin-42(mg152) or lin-42(n1089) mutants (bearing a mutation in the lin-42 gene, homolog to the per gene) exhibit a significantly longer circadian period of 25.2±0.4 h or 25.6±0.5 h, respectively. Our results represent a complete description of the locomotor activity rhythm in C. elegans, with a methodology that allowed us to uncover three of the key features of circadian systems: entrainment, free-running and temperature compensation. In addition, abnormal circadian periods in clock mutants suggest a common molecular machinery responsible for circadian rhythmicity. Our analysis of circadian rhythmicity in C. elegans opens the possibility for further screening for circadian mutations in this species. PMID:19859568

Simonetta, Sergio H.; Migliori, Maria Laura; Romanowski, Andres; Golombek, Diego A.

2009-01-01

163

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

PubMed

Progressive neuronal deterioration accompanied by sensory functions decline is typically observed during aging. On the other hand, structural or functional alterations of specific sensory neurons extend lifespan in the nematode Caenorhabditis elegans. Hormesis is a phenomenon by which the body benefits from moderate stress of various kinds which at high doses are harmful. Several studies indicate that different stressors can hormetically extend lifespan in C. elegans and suggest that hormetic effects could be exploited as a strategy to slow down aging and the development of age-associated (neuronal) diseases in humans. Mitochondria play a central role in the aging process and hormetic-like bimodal dose-response effects on C. elegans lifespan have been observed following different levels of mitochondrial stress. Here we tested the hypothesis that mitochondrial stress may hormetically extend C. elegans lifespan through subtle neuronal alterations. In support of our hypothesis we find that life-lengthening dose of mitochondrial stress reduces the functionality of a subset of ciliated sensory neurons in young animals. Notably, the same pro-longevity mitochondrial treatments rescue the sensory deficits in old animals. We also show that mitochondrial stress extends C. elegans lifespan acting in part through genes required for the functionality of those neurons. To our knowledge this is the first study describing a direct causal connection between sensory neuron dysfunction and extended longevity following mitochondrial stress. Our work supports the potential anti-aging effect of neuronal hormesis and open interesting possibility for the development of therapeutic strategy for age-associated neurodegenerative disorders. PMID:24709340

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

2014-08-01

164

40 CFR 180.1243 - Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement of a...  

Code of Federal Regulations, 2010 CFR

... false Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the...1243 Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from...of the Bacillus subtilis var. amyloliquefaciens strain FZB24 in or on all...

2010-07-01

165

40 CFR 180.1243 - Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement of a...  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Bacillus subtilis var. amyloliquefaciens strain...Tolerances § 180.1243 Bacillus subtilis var. amyloliquefaciens ...tolerance for residues of the Bacillus subtilis var....

2012-07-01

166

40 CFR 180.1243 - Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement of a...  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Bacillus subtilis var. amyloliquefaciens strain...Tolerances § 180.1243 Bacillus subtilis var. amyloliquefaciens ...tolerance for residues of the Bacillus subtilis var....

2011-07-01

167

40 CFR 180.1243 - Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement of a...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Bacillus subtilis var. amyloliquefaciens strain...Tolerances § 180.1243 Bacillus subtilis var. amyloliquefaciens ...tolerance for residues of the Bacillus subtilis var....

2013-07-01

168

Propulsion by sinusoidal locomotion: A motion inspired by Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

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 shed vorticity effects, the propulsive force would be zero at z = 0.569 and z = 1.3 for all k, and for a fixed k the wing would gain the optimal propulsive force when z = 0.82. With the effects of shed vorticity, the propulsive efficiency decreases from 1.0 to 0.5 as k goes to infinity, and the propulsive efficiency increases almost in a linear relationship with k0.

Ulrich, Xialing

169

ccsd00001214 VAR AND ES FOR LINEAR PORTFOLIOS WITH MIXTURE OF  

E-print Network

ccsd­00001214 (version 1) : 27 Feb 2004 VAR AND ES FOR LINEAR PORTFOLIOS WITH MIXTURE OF ELLIPTIC. In this paper, following the generalization of Delta Normal VaR to Delta Mixture Elliptic VaR in Sadefo with the mixture of t-Student distributions. In particular, we give rise to Delta-Mixture-Student VaR and the Delta-Mixture

170

Supplemental Material An MLL/COMPASS subunit functions in the C. elegans dosage compensation complex to  

E-print Network

Supplemental Material An MLL/COMPASS subunit functions in the C. elegans dosage compensation Supplemental Figure 1 ....................................................................................................................1 DPY-30 and ASH-2 antibody specificity. Supplemental Figure 2

Meyer, Barbara

171

Optimal Inverter VAR Control in Distribution Systems with High PV Penetration  

E-print Network

1 Optimal Inverter VAR Control in Distribution Systems with High PV Penetration Masoud Farivar is to demonstrate the benefits of inverter var control on a fast timescale to mitigate rapid and large voltage to the radial OPF problem is presented and used to study the structure of optimal inverter var injection

Low, Steven H.

172

Coordinated Static VAR Compensators and Power System Stabilizers for Damping Power System Oscillations  

Microsoft Academic Search

Technical advantages of coordinating static VAr compensators and power system stabilizers for damping inertial and torsional modes of steam turbine generators are demonstrated. A new control concept for Static VAr Compensators based on using modal speeds as feedback signals, is presented. The concept enables a static VAr compensator to damp all the oscillatory modes as well as controlling the system

R. M. Hamouda; M. R. Iravani; R. Hackam

1987-01-01

173

Capacitor Voltage Control in a Cascaded Multilevel Inverter as a Static Var Generator  

E-print Network

1 Capacitor Voltage Control in a Cascaded Multilevel Inverter as a Static Var Generator M. Li, J. N for a cascaded multilevel inverter to be used for static var compensation. Index Terms-- Multilevel Inverter, Static Var Generator (SVG), Cascade inverter. I. INTRODUCTION Multilevel inverters have gained much

Tolbert, Leon M.

174

Population Genomics of the Immune Evasion (var) Genes of Plasmodium falciparum  

Microsoft Academic Search

Var genes encode the major surface antigen (PfEMP1) of the blood stages of the human malaria parasite Plasmodium falciparum. Differential expression of up to 60 diverse var genes in each parasite genome underlies immune evasion. We compared the diversity of the DBL? domain of var genes sampled from 30 parasite isolates from a malaria endemic area of Papua New Guinea

Alyssa E Barry; Aleksandra Leliwa-Sytek; Livingston Tavul; Heather Imrie; Florence Migot-Nabias; Stuart M Brown; Gilean A. V McVean; Karen P Day

2007-01-01

175

EXC-5 Controls Intracellular Trafficking in Order to Maintain the Apical Structure of the C. elegans Excretory Canal  

E-print Network

The goal of this work is to understand how cells form and maintain tubular shapes. The protein EXC-5 is necessary for a small tubular structure in Caenorhabditis elegans to maintain its shape. C. elegans is a small, easily ...

Mattingly, Brendan Christopher

2011-04-26

176

The effects of maternal corticosterone levels on offspring behavior in fast-and slow-growth garter snakes (Thamnophis elegans)  

E-print Network

snakes (Thamnophis elegans) Kylie A. Robert 1 , Carol Vleck, Anne M. Bronikowski Department of Ecology of the resulting offspring. We treated pregnant female garter snakes (Thamnophis elegans) with low levels

Bronikowski, Anne

177

Biology and Mechanisms of Short RNAs in Caenorhabditis elegans.  

PubMed

The significance of noncoding RNAs in animal biology is being increasingly recognized. The nematode Caenorhabditis elegans has an extensive system of short RNAs that includes microRNAs, piRNAs, and endogenous siRNAs, which regulate development, control life span, provide resistance to viruses and transposons, and monitor gene duplications. Progress in our understanding of short RNAs was stimulated by the discovery of RNA interference, a phenomenon of sequence-specific gene silencing induced by exogenous double-stranded RNA, at the turn of the twenty-first century. This chapter provides a broad overview of the exogenous and endogenous RNAi processes in C. elegans and describes recent advances in genetic, genomic, and molecular analyses of nematode's short RNAs and proteins involved in the RNAi-related pathways. PMID:23890211

Grishok, Alla

2013-01-01

178

C. elegans epigenetic regulation in development and aging  

PubMed Central

The precise developmental map of the Caenorhabditis elegans cell lineage, as well as a complete genome sequence and feasibility of genetic manipulation make this nematode species highly attractive to study the role of epigenetics during development. Genetic dissection of phenotypical traits, such as formation of egg-laying organs or starvation-resistant dauer larvae, has illustrated how chromatin modifiers may regulate specific cell-fate decisions and behavioral programs. Moreover, the transparent body of C. elegans facilitates non-invasive microscopy to study tissue-specific accumulation of heterochromatin at the nuclear periphery. We also review here recent findings on how small RNA molecules contribute to epigenetic control of gene expression that can be propagated for several generations and eventually determine longevity. PMID:24326118

Gonzalez-Aguilera, Cristina; Palladino, Francesca

2014-01-01

179

Transcriptional Regulation of Gene Expression in C. elegans  

PubMed Central

Protein coding gene sequences are converted to mRNA by the highly regulated process of transcription. The precise temporal and spatial control of transcription for many genes is an essential part of development in metazoans. Thus, understanding the molecular mechanisms underlying transcriptional control is essential to understanding cell fate determination during embryogenesis, post-embryonic development, many environmental interactions, and disease-related processes. Studies of transcriptional regulation in C. elegans exploit its genomic simplicity and physical characteristics to define regulatory events with single cell and minute time scale resolution. When combined with the genetics of the system, C. elegans offers a unique and powerful vantage point from which to study how chromatin-associated protein and their modifications interact with transcription factors and their binding sites to yield precise control of gene expression through transcriptional regulation. PMID:23801596

Reinke, Valerie; Krause, Michael; Okkema, Peter

2013-01-01

180

Measuring the effects of high CO? levels in Caenorhabditis elegans.  

PubMed

Carbon dioxide (CO2) is an important molecule in cell metabolism. It is also a byproduct of many physiological processes. In humans, impaired lung function and lung diseases disrupt the body's ability to dispose of CO2 and elevate its levels in the body (hypercapnia). Animal models allow further understanding of how CO2 is sensed in the body and what are the physiological responses to high CO2 levels. This information can provide new strategies in the battle against the detrimental effects of CO2 accumulation in lung diseases. The nematode Caenorhabditis elegans provides us with such a model animal due to its natural ability to sense and navigate through varying concentrations of CO2, as well as the fact that it can be genetically manipulated with ease. Here we describe the different methods used to measure the effects elevated levels of CO2 have on the molecular sensing mechanism and physiology of C. elegans. PMID:24650565

Zuela, Noam; Friedman, Nurit; Zaslaver, Alon; Gruenbaum, Yosef

2014-08-01

181

High-throughput imaging of neuronal activity in Caenorhabditis elegans  

PubMed Central

Neuronal responses to sensory inputs can vary based on genotype, development, experience, or stochastic factors. Existing neuronal recording techniques examine a single animal at a time, limiting understanding of the variability and range of potential responses. To scale up neuronal recordings, we here describe a system for simultaneous wide-field imaging of neuronal calcium activity from at least 20 Caenorhabditis elegans animals under precise microfluidic chemical stimulation. This increased experimental throughput was used to perform a systematic characterization of chemosensory neuron responses to multiple odors, odor concentrations, and temporal patterns, as well as responses to pharmacological manipulation. The system allowed recordings from sensory neurons and interneurons in freely moving animals, whose neuronal responses could be correlated with behavior. Wide-field imaging provides a tool for comprehensive circuit analysis with elevated throughput in C. elegans. PMID:24145415

Larsch, Johannes; Ventimiglia, Donovan; Bargmann, Cornelia I.; Albrecht, Dirk R.

2013-01-01

182

In vitro culture of C. elegans somatic cells.  

PubMed

Because of technical hurdles, large-scale cell culture methods have not been widely exploited until recently for the study of Caenorhabditis elegans. Culturing differentiated cells from larvae and adult worms is probably not technically feasible because of difficulties in removing the animal's cuticle and dissociating cells. In contrast, large numbers of developing embryo cells can be isolated relatively easily. When placed in culture, embryo cells undergo terminal differentiation within 24 h. Cultured embryo cells have been used recently to characterize ion channel function and regulation and to determine cell specific gene expression patterns. This chapter will provide a detailed description of the methods for isolating and culturing C. elegans embryo cells. PMID:16988440

Strange, Kevin; Morrison, Rebecca

2006-01-01

183

Immunofluorscent localization of proteins in C. elegans muscle  

PubMed Central

Summary C. elegans is a premier model genetic system for discovering new information about the assembly and maintenance of striated muscle. The localization of a protein within a nematode muscle cell can reveal important clues to its function. In C. elegans, proteins can be localized by two different methods at the light microscopy level: GFP tagged proteins and indirect immunofluorescence. Although there are advantages and disadvantages of each method, antibodies can be used to localize proteins expressed at endogenous levels and without tags that might interfere with function. Immunolocalization requires efficient and effective methods of fixation. Here, we describe in detail two different methods for fixation of adult worms, the Nonet method and the Constant Spring method. We also discuss the advantages and disadvantages of each, and how to choose between them. These methods are also useful for localizing proteins expressed in other cell types. PMID:22130837

Wilson, Kristy J.; Qadota, Hiroshi; Benian, Guy M.

2013-01-01

184

Aging in the nervous system of Caenorhabditis elegans  

PubMed Central

It has recently been described that aging in C. elegans is accompanied by the progressive development of morphological changes in the nervous system. These include novel outgrowths from the cell body or axonal process, as well as blebbing and beading along the length of the axon. The formation of these structures is regulated by numerous molecular players including members of the well-conserved insulin/insulin growth factor-like (IGF)-1 signaling and mitogen-activated protein (MAP) kinase pathways. This review summarizes the recent literature on neuronal aging in C. elegans, including our own findings, which indicate a role for protein with tau-like repeats (PTL-1), the homolog of mammalian tau and MAP2/4, in maintaining neuronal integrity during aging. PMID:24255742

Chew, Yee Lian; Fan, Xiaochen; Götz, Jürgen; Nicholas, Hannah R.

2013-01-01

185

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

PubMed

The nematode C. elegans displays complex dynamical behaviors that are commonly used to identify relevant phenotypes. Although its maintenance is straightforward, sorting large populations of worms when looking for a behavioral phenotype is difficult, time consuming and hardly quantitative when done manually. Interestingly, when submitted to a moderate electric field, worms move steadily along straight trajectories. Here, we report an inexpensive method to measure worms crawling velocities and sort them within a few minutes by taking advantage of their electrotactic skills. This method allows to quantitatively measure the effect of mutations and aging on worm's crawling velocity. We also show that worms with different locomotory phenotypes can be spatially sorted, fast worms traveling away from slow ones. Group of nematodes with comparable locomotory fitness could then be isolated for further analysis. C. elegans is a growing model for neurodegenerative diseases and using electrotaxis for self-sorting can improve the high-throughput search of therapeutic bio-molecules. PMID:21326598

Manière, Xavier; Lebois, Félix; Matic, Ivan; Ladoux, Benoit; Di Meglio, Jean-Marc; Hersen, Pascal

2011-01-01

186

SKIP is an indispensable factor for Caenorhabditis elegans development.  

PubMed

SKI-binding protein (SKIP) is a transcription cofactor present in all eukaryotes. Here we show that SKIP is a unique protein that is required for Caenorhabditis elegans viability and development. Expression of CeSKIP (skp-1) assayed by RT-PCR and by GFP fluorescence in transgenic lines starts in embryos and continues to adulthood. Loss of CeSKIP activity by RNA-mediated inhibition results in early embryonic arrest similar to that seen following inhibition of RNA polymerase II. RNA polymerase II phosphorylation appears normal early in CeSKIP RNA-mediated inhibition treated embryos although the expression of several embryonic GFP reporter genes is severely restricted or absent. Our data suggest that CeSKIP is an essential component of many RNA polymerase II transcription complexes and is indispensable for C. elegans development. PMID:12084813

Kostrouchova, Marta; Housa, Daniel; Kostrouch, Zdenek; Saudek, Vladimir; Rall, Joseph Edward

2002-07-01

187

SKIP is an indispensable factor for Caenorhabditis elegans development  

PubMed Central

SKI-binding protein (SKIP) is a transcription cofactor present in all eukaryotes. Here we show that SKIP is a unique protein that is required for Caenorhabditis elegans viability and development. Expression of CeSKIP(skp-1) assayed by RT-PCR and by GFP fluorescence in transgenic lines starts in embryos and continues to adulthood. Loss of CeSKIP activity by RNA-mediated inhibition results in early embryonic arrest similar to that seen following inhibition of RNA polymerase II. RNA polymerase II phosphorylation appears normal early in CeSKIP RNA-mediated inhibition treated embryos although the expression of several embryonic GFP reporter genes is severely restricted or absent. Our data suggest that CeSKIP is an essential component of many RNA polymerase II transcription complexes and is indispensable for C. elegans development. PMID:12084813

Kostrouchova, Marta; Housa, Daniel; Kostrouch, Zdenek; Saudek, Vladimir; Rall, Joseph Edward

2002-01-01

188

C. elegans as a model for membrane traffic  

PubMed Central

The counterbalancing action of the endocytosis and secretory pathways maintains a dynamic equilibrium that regulates the composition of the plasma membrane, allowing it to maintain homeostasis and to change rapidly in response to changes in the extracellular environment and/or intracellular metabolism. These pathways are intimately integrated with intercellular signaling systems and play critical roles in all cells. Studies in Caenorhabditis elegans have revealed diverse roles of membrane trafficking in physiology and development and have also provided molecular insight into the fundamental mechanisms that direct cargo sorting, vesicle budding, and membrane fisson and fusion. In this review, we summarize progress in understanding membrane trafficking mechanisms derived from work in C. elegans, focusing mainly on work done in non-neuronal cell-types, especially the germline, early embryo, coelomocytes, and intestine. PMID:24778088

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

2014-01-01

189

Running Worms: C. elegans Self-Sorting by Electrotaxis  

PubMed Central

The nematode C. elegans displays complex dynamical behaviors that are commonly used to identify relevant phenotypes. Although its maintenance is straightforward, sorting large populations of worms when looking for a behavioral phenotype is difficult, time consuming and hardly quantitative when done manually. Interestingly, when submitted to a moderate electric field, worms move steadily along straight trajectories. Here, we report an inexpensive method to measure worms crawling velocities and sort them within a few minutes by taking advantage of their electrotactic skills. This method allows to quantitatively measure the effect of mutations and aging on worm's crawling velocity. We also show that worms with different locomotory phenotypes can be spatially sorted, fast worms traveling away from slow ones. Group of nematodes with comparable locomotory fitness could then be isolated for further analysis. C. elegans is a growing model for neurodegenerative diseases and using electrotaxis for self-sorting can improve the high-throughput search of therapeutic bio-molecules. PMID:21326598

Manière, Xavier; Lebois, Félix; Matic, Ivan; Ladoux, Benoit; Di Meglio, Jean-Marc; Hersen, Pascal

2011-01-01

190

The genetics of ivermectin resistance in Caenorhabditis elegans  

PubMed Central

The ability of organisms to evolve resistance threatens the effectiveness of every antibiotic drug. We show that in the nematode Caenorhabditis elegans, simultaneous mutation of three genes, avr-14, avr-15, and glc-1, encoding glutamate-gated chloride channel (GluCl) ?-type subunits confers high-level resistance to the antiparasitic drug ivermectin. In contrast, mutating any two channel genes confers modest or no resistance. We propose a model in which ivermectin sensitivity in C. elegans is mediated by genes affecting parallel genetic pathways defined by the family of GluCl genes. The sensitivity of these pathways is further modulated by unc-7, unc-9, and the Dyf (dye filling defective) genes, which alter the structure of the nervous system. Our results suggest that the evolution of drug resistance can be slowed by targeting antibiotic drugs to several members of a multigene family. PMID:10716995

Dent, Joseph A.; Smith, McHardy M.; Vassilatis, Demetrios K.; Avery, Leon

2000-01-01

191

Cytotoxic constituents from Solidago virga-aurea var. gigantea MIQ.  

PubMed

Activity-guided fractionation of the whole plant of Solidago virga-aurea var. gigantea M(IQ). (Compositae) has led to the isolation of three cytotoxic compounds, erythrodiol-3-acetate (1), alpha-tocopherol-quinone (2), and trans-phytol (3) from the hexane soluble fraction. It is the first report of those compounds from the genus. PMID:10615872

Sung, J H; Lee, J O; Son, J K; Park, N S; Kim, M R; Kim, J G; Moon, D C

1999-12-01

192

Cytotoxic constituents from Solidago virga-aurea var. gigantea MIQ  

Microsoft Academic Search

Activity-guided fractionation of the whole plant ofSolidago virga-aurea var.gigantea MIQ. (Compositae) has led to the isolation of three cytotoxic compounds, erythrodiol-3-acetate (1), ?-tocopherol-quinone (2), and trans-phytol (3) from the hexane soluble fraction. It is the first report of those compounds from the genus.

Jong Hoon Sung; Jung Ock Lee; Jong Kun Son; No Sang Park; Mi Ran Kim; Jae Gil Kim; Dong Cheul Moon

1999-01-01

193

Starch-metabolic growth characteristics of Humicola grisea var. thermoidea  

Microsoft Academic Search

Very low extracellular amylase levels measured during the growth of Humicola grisea var. thermoidea in starch-yeast medium appeared to be sufficient to metabolize the starch relatively rapidly. A maximum mycelial dry weight of about 65 mg was measure after six days of incubation.

P. R. Adams

1985-01-01

194

New Static Var Control Using Force-Commutated Inverters  

Microsoft Academic Search

This paper describes the system outline and the operating results of a new type of 20MVA Static VAR Generator (SVG), which is already in operation in electric power field since January of 1980. This SVG consists of force-commutated inverters of the voltage source and can be operated in both, inductive and capacitive modes, by simple control of the output voltage

Yoshihiko Sumi; Yoshinobu Harumoto; Taizo Hasegawa; Masao Yano; Kazuo Ikeda; Toshiaki Matsuura

1981-01-01

195

Comparison of multilevel inverters for static VAr compensation  

Microsoft Academic Search

Inverter-based static VAr compensators (SVCs) can benefit from the use of a multilevel invertor structure which allows the elimination of the step-up transformer. The inherent high quality of the multistep waveform allows operation without PWM, thus high switching losses are avoided. This paper discusses the issues affecting the application of multilevel invertor structures as reactive power compensators and compares the

CLARK HOCHGRAF; ROBERT LASSETER; DEEPAK DIVAN; T.A. Lipo

1994-01-01

196

Firm growth and productivity growth: evidence from a panel VAR  

Microsoft Academic Search

This article offers new insights into the processes of firm growth by applying a reduced-form Vector Autoregression (VAR) model to longitudinal panel data on French manufacturing firms. We observe the co-evolution of key variables such as growth of employment, sales and gross operating surplus, as well as growth of multifactor productivity. It seems that employment growth is negatively associated with

Alex Coad; Tom Broekel

2011-01-01

197

Neolignan and flavonoid glycosides in Juniperus communis var. depressa  

Microsoft Academic Search

Two neolignan glycosides (junipercomnosides A and B) were isolated from aerial parts of Juniperus communis var. depressa along with two known neolignan glycosides and seven flavonoid glycosides. The structures of the isolated compounds were determined by spectral analysis, in particular by 2D-NMR analysis. The significance of distribution of flavonoids in the chemotaxonomy of genus Juniperus was also discussed.

Tsutomu Nakanishi; Naoki Iida; Yuka Inatomi; Hiroko Murata; Akira Inada; Jin Murata; Frank A. Lang; Munekazu Iinuma; Toshiyuki Tanaka

2004-01-01

198

Neolignan and flavonoid glycosides in Juniperus communis var. depressa.  

PubMed

Two neolignan glycosides (junipercomnosides A and B) were isolated from aerial parts of Juniperus communis var. depressa along with two known neolignan glycosides and seven flavonoid glycosides. The structures of the isolated compounds were determined by spectral analysis, in particular by 2D-NMR analysis. The significance of distribution of flavonoids in the chemotaxonomy of genus Juniperus was also discussed. PMID:14732280

Nakanishi, Tsutomu; Iida, Naoki; Inatomi, Yuka; Murata, Hiroko; Inada, Akira; Murata, Jin; Lang, Frank A; Iinuma, Munekazu; Tanaka, Toshiyuki

2004-01-01

199

Immunomodulatory Activity of Xanthones from Calophyllum teysmannii var. inuphylloide.  

PubMed

Nine xanthones, including 3-(4-hydroxy-3-metnylbutyl)-4,8-dihydroxyxanthone, were isolated from the wood of a Thai collection of CALOPHYLLUM TEYSMANNII Miq. var. INUPHYLLOIDE (King) P. Stephen. Immunomodulatory activities of eight of these have been investigated. PMID:17260263

Gonzalez, M J; Nascimento, M S; Cidade, H M; Pinto, M M; Kijjoa, A; Anantachoke, C; Silva, A M; Herz, W

1999-05-01

200

A Preliminary Study of Acarospora smaragdula var. lesdainii in California  

Microsoft Academic Search

1 ABSTRACT. - The current state of Acarospora studies is discussed. Acarospora hassei Herre and Acarospora particularis H. Magnusson are placed in synonymy with Acarospora smaragdula var. lesdainii (Harmand in A.L. Smith) H. Magnusson. A lectotype is selected for A. hassei Herre.

KERRY KNUDSEN

201

Equine ringworm due to Trichophyton mentagrophytes var. quinckeanum  

Microsoft Academic Search

Summary T. mentagrophytes var.quinckeanum was isolated from a case of equine tinea and this finding is thought to be unique. Although it is considered that the fungus is closely related toT. mentagrophytes, the small differences in the relative pathogenicity for animals and man, the unusual clinical pattern which can be seen, and the downy nature of primary isolates on Sabouraud's

Geraldine W. Brown; G. F. Donald

1964-01-01

202

Genomic Analysis of Stress Response against Arsenic in Caenorhabditis elegans  

PubMed Central

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. PMID:23894281

Sahu, Surasri N.; Lewis, Jada; Patel, Isha; Bozdag, Serdar; Lee, Jeong H.; Sprando, Robert; Cinar, Hediye Nese

2013-01-01

203

Biotransformation of adrenosterone by filamentous fungus, Cunninghamella elegans.  

PubMed

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. PMID:17889091

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

2007-12-01

204

Lettuce black root rot — a disease caused by Chalara elegans  

Microsoft Academic Search

Lettuce plants in several fields in south-eastern Queensland were affected by a black root rot resulting in slow growth, small\\u000a head size and harvest reductions. Isolation and pathogenicity tests showed Chalara elegans was the causal fungus. The host range included bean and cucurbits but not capsicum, celery, cotton, eggplant, parsley,\\u000a radish or tomato. The weed Sonchus oleraceus was a natural

R G. O’Brien

1994-01-01

205

OSMOTIC AVOIDANCE DEFECTIVE MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS  

Microsoft Academic Search

A wild-type strain of the nematode Caenorhabditis elegans has been shown to avoid high concentrations of a number of sugars and salts. Individual and population assays for this response were developed and mutants were selected for their inability to avoid high concentrations of fructose or NaC1. Seven nonavoiding mutants representing six complementation groups were isolated and characterized. Genetic studies indicate

JOSEPH G. CULOTTI; RICHARD L. RUSSELL

1978-01-01

206

A soil bioassay using the nematode Caenorhabditis elegans  

SciTech Connect

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

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

1999-07-01

207

Noncanonical cell death programs in the nematode Caenorhabditis elegans  

Microsoft Academic Search

Genetic studies of the nematode Caenorhabditis elegans have uncovered four genes, egl-1 (BH3 only), ced-9 (Bcl-2 related), ced-4 (apoptosis protease activating factor-1), and ced-3 (caspase), which function in a linear pathway to promote developmental cell death in this organism. While this core pathway functions in many cells, recent studies suggest that additional regulators, acting on or in lieu of these

E S Blum; M Driscoll; S Shaham

2008-01-01

208

trt-1 Is the Caenorhabditis elegans Catalytic Subunit of Telomerase  

Microsoft Academic Search

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

Bettina Meier; Iuval Clejan; Yan Liu; Mia Lowden; Anton Gartner; Jonathan Hodgkin; Shawn Ahmed

2006-01-01

209

Tomosyn Inhibits Synaptic Vesicle Priming in Caenorhabditis elegans  

E-print Network

microscopy; GFP, green fluorescent protein; NMJ, neuromuscular junction; RNAi, RNA interference; SNARE, soluble NSF attachment protein receptors; TOM-1Ct, C-terminal coiled-coil motif of TOM-1; WT, wild type * To whom correspondence should be addressed. E... directly assayed the physiological phenotype of tomosyn loss-of-function mutants at the Caenorhabditis elegans neuromuscular junction (NMJ). Our results indicate that tomosyn inhibits synaptic transmission through actions that regulate the size...

Gracheva, Elena O.; Burdina, Anna O.; Holgado, Andrea M.; Berthelot-Grosjean, Martine; Ackley, Brian D.; Hadwiger, Gayla; Nonet, Michael L.; Weimer, Robby M.; Richmond, Janet E.

2006-07-25

210

Spaceflight and ageing: reflecting on Caenorhabditis elegans in space.  

PubMed

The prospect of space travel continues to capture the imagination. Several competing companies are now promising flights for the general population. Previously, it was recognized that many of the physiological changes that occur with spaceflight are similar to those seen with normal ageing. This led to the notion that spaceflight can be used as a model of accelerated ageing and raised concerns about the safety of individuals engaging in space travel. Paradoxically, however, space travel has been recently shown to be beneficial to some aspects of muscle health in the tiny worm Caenorhabditis elegans. C. elegans is a commonly used laboratory animal for studying ageing. C. elegans displays age-related decline of some biological processes observed in ageing humans, and about 35% of C. elegans' genes have human homologs. Space flown worms were found to have decreased expression of a number of genes that increase lifespan when expressed at lower levels. These changes were accompanied by decreased accumulation of toxic protein aggregates in ageing worms' muscles. Thus, in addition to spaceflight producing physiological changes that are similar to accelerated ageing, it also appears to produce some changes similar to delayed ageing. Here, we put forward the hypothesis that in addition to the previously well-appreciated mechanotransduction changes, neural and endocrine signals are altered in response to spaceflight and that these may have both negative (e.g. less muscle protein) and some positive consequences (e.g. healthier muscles), at least for invertebrates, with respect to health in space. Given that changes in circulating hormones are well documented with age and in astronauts, our view is that further research into the relationship between metabolic control, ageing, and adaptation to the environment should be productive in advancing our understanding of the physiology of both spaceflight and ageing. PMID:24217152

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

2014-01-01

211

Analysis of Intraflagellar Transport in C. elegans Sensory Cilia  

Microsoft Academic Search

Cilia are assembled and maintained by intraflagellar transport (IFT), the motor-dependent, bidirectional movement of multiprotein complexes, called IFT particles, along the axoneme. The sensory cilia of Caenorhabditis elegans represent very useful objects for studying IFT because of the availability of in vivo time-lapse fluorescence microscopy assays of IFT and multiple ciliary mutants. In this system there are 60sensory neurons, each

Limin Hao; Seyda Acar; James Evans; Guangshuo Ou; Jonathan M. Scholey

2009-01-01

212

Caenorhabditis elegans Neuromuscular Junction: GABA Receptors and Ivermectin Action  

PubMed Central

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 that their combination is a good strategy to overcome the increasing resistance of parasites, an issue of global concern for human and animal health. PMID:24743647

Hernando, Guillermina; Bouzat, Cecilia

2014-01-01

213

nhl-2 Modulates MicroRNA Activity in Caenorhabditis elegans  

Microsoft Academic Search

SUMMARY TRIM-NHL proteins represent a large class of metazoan proteins implicated in development and disease. We demonstrate that a C. elegans TRIM- NHL protein, NHL-2, functions as a cofactor for the microRNA-induced silencing complex (miRISC) and thereby enhances the posttranscriptional repression of several genetically verified microRNA targets, including hbl-1 and let-60\\/Ras (by the let-7 family of microRNAs) and cog-1 (by

Christopher M. Hammell; Isabella Lubin; Peter R. Boag; T. Keith Blackwell; Victor R. Ambros

2009-01-01

214

Direct micro-mechanical measurements on C. elegans  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

215

Tat-mediated protein delivery in living Caenorhabditis elegans  

SciTech Connect

The Tat protein from HIV-1 fused with heterologous proteins traverses biological membranes in a transcellular process called: protein transduction. This has already been successfully exploited in various biological models, but never in the nematode worm Caenorhabditis elegans. TAT-eGFP or GST-eGFP proteins were fed to C. elegans worms, which resulted in the specific localization of Tat-eGFP to epithelial intestinal cells. This system represents an efficient tool for transcellular transduction in C. elegans intestinal cells. Indeed, this approach avoids the use of tedious purification steps to purify the TAT fusion proteins and allows for rapid analyses of the transduced proteins. In addition, it may represent an efficient tool to functionally analyze the mechanisms of protein transduction as well as to complement RNAi/KO in the epithelial intestinal system. To sum up, the advantage of this technology is to combine the potential of bacterial expression system and the Tat-mediated transduction technique in living worm.

Delom, Frederic [Department of Surgery, McGill University, Montreal, Que. (Canada); Fessart, Delphine [Department of Medicine, McGill University, Montreal, Que. (Canada); Caruso, Marie-Elaine [Department of Surgery, McGill University, Montreal, Que. (Canada); Chevet, Eric [Department of Surgery, McGill University, Montreal, Que. (Canada) and Department of Medicine, McGill University, Montreal, Que. (Canada) and Department of Anatomy and Cell Biology, McGill University, Montreal, Que. (Canada) and INSERM, E362, Universite Bordeaux 2, Bordeaux (France)]. E-mail: eric.chevet@mcgill.ca

2007-01-19

216

Optical reversal of halothane-induced immobility in C. elegans.  

PubMed

Volatile anesthetics (VAs) cause profound neurological effects, including reversible loss of consciousness and immobility. Despite their widespread use, the mechanism of action of VAs remains one of the unsolved puzzles of neuroscience [1, 2]. Genetic studies in Caenorhabditis elegans [3, 4], Drosophila [3, 5], and mice [6-9] indicate that ion channels controlling the neuronal resting membrane potential (RMP) also control anesthetic sensitivity. Leak channels selective for K(+) [10-13] or permeable to Na(+) [14] are critical for establishing RMP. We hypothesized that halothane, a VA, caused immobility by altering the neuronal RMP. In C. elegans, halothane-induced immobility is acutely and completely reversed by channelrhodopsin-2 based depolarization of the RMP when expressed specifically in cholinergic neurons. Furthermore, hyperpolarizing cholinergic neurons via halorhodopsin activation increases sensitivity to halothane. The sensitivity of C. elegans to halothane can be altered by 25-fold by either manipulation of membrane conductance with optogenetic methods or generation of mutations in leak channels that set the RMP. Immobility induced by another VA, isoflurane, is not affected by these treatments, thereby excluding the possibility of nonspecific hyperactivity. The sum of our data indicates that leak channels and the RMP are important determinants of halothane-induced general anesthesia. PMID:22137475

Singaram, Vinod K; Somerlot, Benjamin H; Falk, Scott A; Falk, Marni J; Sedensky, Margaret M; Morgan, Philip G

2011-12-20

217

The Redox System in C. elegans, a Phylogenetic Approach  

PubMed Central

Oxidative stress is a toxic state caused by an imbalance between the production and elimination of reactive oxygen species (ROS). ROS cause oxidative damage to cellular components such as proteins, lipids, and nucleic acids. While the role of ROS in cellular damage is frequently all that is noted, ROS are also important in redox signalling. The “Redox Hypothesis" has been proposed to emphasize a dual role of ROS. This hypothesis suggests that the primary effect of changes to the redox state is modified cellular signalling rather than simply oxidative damage. In extreme cases, alteration of redox signalling can contribute to the toxicity of ROS, as well as to ageing and age-related diseases. The nematode species Caenorhabditis elegans provides an excellent model for the study of oxidative stress and redox signalling in animals. We use protein sequences from central redox systems in Homo sapiens, Drosophila melanogaster, and Saccharomyces cerevisiae to query Genbank for homologous proteins in C. elegans. We then use maximum likelihood phylogenetic analysis to compare protein families between C. elegans and the other organisms to facilitate future research into the genetics of redox biology. PMID:22899914

Johnston, Andrew D.; Ebert, Paul R.

2012-01-01

218

Mechanosensitive unpaired innexin channels in C. elegans touch neurons.  

PubMed

Invertebrate innexin proteins share sequence homology with vertebrate pannexins and general membrane topology with both pannexins and connexins. While connexins form gap junctions that mediate intercellular communication, pannexins are thought to function exclusively as plasma membrane channels permeable to both ions and small molecules. Undoubtedly, certain innexins function as gap junction proteins. However, due to sequence similarity to pannexins, it was postulated that innexins also function as plasma membrane channels. Indeed, some of the leech innexins were found to mediate ATP release as unpaired membrane channels with shared pharmacology to pannexin channels. We show here that Caenorhabditis elegans touch-sensing neurons express a mechanically gated innexin channel with a conductance of ?1 nS and voltage-dependent and K(+)-selective subconductance state. We also show that C. elegans touch neurons take up ethidium bromide through a mechanism that is activated and blocked by innexin activating stimuli and inhibitors, respectively. Finally, we present evidence that touch neurons' innexins are required for cell death induced by chemical ischemia. Our work demonstrates that innexins function as plasma membrane channels in native C. elegans neurons, where they may play a role in pathological cell death. PMID:25252948

Sangaletti, Rachele; Dahl, Gerhard; Bianchi, Laura

2014-11-15

219

Two-color GFP expression system for C. elegans.  

PubMed

We describe the use of modified versions of the Aequora victoria green fluorescent protein (GFP) to simultaneously follow the expression and distribution of two different proteins in the nematode, Caenorhabditis elegans. A cyan-colored GFP derivative, designated CFP, contains amino acid (aa) substitutions Y66W, N146I, M153T and V163A relative to the original GFP sequence and is similar to the previously reported "W7" form. A yellow-shifted GFP derivative, designated YFP, contains aa substitutions S65G, V68A, S72A and T203Y and is similar to the previously described "I0C" variant. Coding regions for CFP and YFP were constructed in the context of a high-activity C. elegans expression system. Previously characterized promoters and localization signals have been used to express CFP and YFP in C. elegans. Filter sets designed to distinguish YFP and CFP fluorescence spectra allowed visualization of the two distinct forms of GFP in neurons and in muscle cells. A series of expression vectors carrying CFP and YFP have been constructed and are being made available to the scientific community. PMID:10337485

Miller, D M; Desai, N S; Hardin, D C; Piston, D W; Patterson, G H; Fleenor, J; Xu, S; Fire, A

1999-05-01

220

Amanitin and phallotoxin concentration in Amanita phalloides var. alba mushroom.  

PubMed

Although rarely seen, Amanita phalloides var. alba, a variety of A. phalloides type mushrooms, causes mushroom poisoning resulting in death. Since it is frequently confused with some edible mushrooms due to its white colored cap and macroscopic appearance, it becomes important in toxicological terms. Knowledge of the toxin amount contained in this mushroom type is invaluable in the treatment of cases involving poisoning. In this study, we examined the toxin levels of various parts of the A. phalloides var. alba mushroom growing Duzce region of Turkey. Toxin analyses were carried out for A. phalloides var. alba, which were collected from the forests Duzce region of Turkey in 2011, as a whole and also separately in its spore, pileus, gills, stipe and volva parts. The alpha amanitin, beta amanitin, gamma amanitin, phalloidin and phallacidine analyses of the mushrooms were carried out using the RP-HPLC method. A genetic analysis of the mushroom showed that it had similar genetic characteristics as A. phalloides and was a variety of it. The lowest toxins quantity was detected in spores, volva and stipe among all parts of the mushroom. The maximum amount of amatoxins was measured in the gills. The pileus also contained a high amount of amatoxins. Generally, amatoxins and phallotoxin concentrations were lower as compared to A. phalloides, but interestingly all toxins other than gamma toxin were higher in the spores of A. phalloides var. alba. The amount of toxin in all of its parts had sufficient concentrations to cause death. With this study, the amatoxin and phallotoxin concentrations in A. phalloides var. alba mushroom and in its parts have been revealed in detail for the first time. PMID:24139877

Kaya, Ertugrul; Yilmaz, Ismail; Sinirlioglu, Zeynep Aydin; Karahan, Selim; Bayram, Recep; Yaykasli, Kursat Oguz; Colakoglu, Serdar; Saritas, Ayhan; Severoglu, Zeki

2013-12-15

221

Chemopreventive and Anticancer Activities of Allium victorialis var. platyphyllum Extracts  

PubMed Central

Background: Allium victorialis var. platyphyllum is an edible perennial herb and has been used as a vegetable or as a Korean traditional medicine. Allium species have received much attention owing to their diverse pharmacological properties, including antioxidative, anti-inflammatory, and anticancer activities. However, A. victorialis var. platyphyllum needs more study. Methods: The chemopreventive potential of A. victorialis var. platyphyllum methanol extracts was examined by measuring 12-O-tetra-decanoylphorbol 13-acetate (TPA)-induced superoxide anion production in the differentiated HL-60 cells, TPA-induced mouse ear edema, and Ames/Salmonella mutagenicity. The apoptosis-inducing capabilities of the extracts were evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, 4’,6-diamidino-2-phenylindole staining, and the DNA fragmentation assay in human colon cancer HT-29 cells. Antimetastatic activities of the extracts were also investigated in an experimental mouse lung metastasis model. Results: The methanol extracts of A. victorialis var. platyphyllum rhizome (AVP-R) and A. victorialis var. platyphyllum stem (AVP-S) dose-dependently inhibited the TPA-induced generation of superoxide anion in HL-60 cells and TPA-induced ear edema in mice, as well as 7,12-dimethylbenz[a]anthracene (DMBA) and tert-butyl hydroperoxide (t-BOOH) -induced bacterial mutagenesis. AVP-R and AVP-S reduced cell viability in a dose-related manner and induced apoptotic morphological changes and internucleosomal DNA fragmentation in HT-29 cells. In the experimental mouse lung metastasis model, the formation of tumor nodules in lung tissue was significantly inhibited by the treatment of the extracts. Conclusions: AVP-R and AVP-S possess antioxidative, anti-inflammatory, antimutagenic, proapoptotic, and antimetastatic activities. Therefore, these extracts can serve as a beneficial supplement for the prevention and treatment of cancer. PMID:25337587

Kim, Hyun-Jeong; Park, Min Jeong; Park, Hee-Juhn; Chung, Won-Yoon; Kim, Ki-Rim; Park, Kwang-Kyun

2014-01-01

222

The thrombospondin repeat containing protein MIG-21 controls a leftright asymmetric Wnt signaling response in migrating C. elegans neuroblasts  

E-print Network

response in migrating C. elegans neuroblasts Teije C. Middelkoop a , Lisa Williams b , Pei-Tzu Yang Keywords: C. elegans Wnt Cell migration Signal transduction Cell polarity Wnt proteins are secreted migration of the C. elegans Q neuroblasts as a model to study how two initially equiva- lent cells

van Oudenaarden, Alexander

223

Caenorhabditis elegans (Nematoda) and Hypoaspis aculeifer (Acari) as new ecotoxicological tools for the assessment of organic materials used in  

E-print Network

terrestrial and aquatic bio-assays. In addition, two new model organisms (the nematode Caenorhabditis elegans. In this work, the possibility of including two new model organisms (the nematode Caenorhabditis elegans. elegans, which is a well-known organism and easy to culture, was selected due to the possibility

Paris-Sud XI, Université de

224

Adaptive divergence within and between ecotypes of the terrestrial garter snake, Thamnophis elegans, assessed with FST-QST  

E-print Network

Adaptive divergence within and between ecotypes of the terrestrial garter snake, Thamnophis elegans study system, populations of the terrestrial garter snake (Thamnophis elegans) in the Eagle Lake basin-statistics; scalation. Abstract Populations of the terrestrial garter snake (Thamnophis elegans) around Eagle Lake

Palumbi, Stephen

225

Evidence for Selection on Thermoregulation: Effects of Temperature on Embryo Mortality in the Garter Snake Thamnophis elegans  

E-print Network

in the Garter Snake Thamnophis elegans RYAN P. O'DONNELL AND STEVAN J. ARNOLD Despite widespread belief-four female Thamnophis elegans were maintained at one of nine constant temperatures during pregnancy (21­33 C snake Thamnophis elegans. Two studies found evidence for the effects of thermoregulation on fitness

Arnold, Stevan J.

226

ccsd-00001214(version1):27Feb2004 VAR AND ES FOR LINEAR PORTFOLIOS WITH MIXTURE OF  

E-print Network

ccsd-00001214(version1):27Feb2004 VAR AND ES FOR LINEAR PORTFOLIOS WITH MIXTURE OF ELLIPTIC, following the generalization of Delta Normal VaR to Delta Mixture Elliptic VaR in Sadefo-Kamdem [3], we give and explicit formula to estimate linear VaR and ES when the risk factors changes with the mixture of t

Paris-Sud XI, Université de

227

Genetic control of programmed cell death in the Caenorhabditis elegans hermaphrodite germline  

Microsoft Academic Search

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same

Tina L. Gumienny; Eric Lambie; Erika Hartwieg; H. Robert Horvitz; Michael O. Hengartner

1999-01-01

228

Redundant control of the Caenorhabditis elegans sperm oocyte switch by PUF-8 and FBF-1,  

E-print Network

is also critical for the hermaphrodite sperm oocyte switch. Most puf-8 mutant hermaphrodites make both-1 puf-8 double mutants fail in the hermaphrodite sperm oocyte switch. Therefore, puf-8 and fbf-1 act- rhabditis elegans sperm oocyte switch. C. elegans can exist as either a self-fertile hermaphrodite or a male

Kimble, Judith

229

Identification of ciliary and ciliopathy genes in Caenorhabditis elegans through comparative genomics  

Microsoft Academic Search

Background: The recent availability of genome sequences of multiple related Caenorhabditis species has made it possible to identify, using comparative genomics, similarly transcribed genes in Caenorhabditis elegans and its sister species. Taking this approach, we have identified numerous novel ciliary genes in C. elegans, some of which may be orthologs of unidentified human ciliopathy genes. Results: By screening for genes

Nansheng Chen; Allan Mah; Oliver E Blacque; Jeffrey Chu; Kiran Phgora; Mathieu W Bakhoum; C Rebecca; Hunt Newbury; Jaswinder Khattra; Susanna Chan; Anne Go; Evgeni Efimenko; Robert Johnsen; Prasad Phirke; Peter Swoboda; Marco Marra; Donald G Moerman; Michel R Leroux; David L Baillie; Lincoln D Stein; West Mall

2006-01-01

230

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

ERIC Educational Resources Information Center

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…

Myers, Edith M.

2014-01-01

231

Voltage-Gated Calcium Channels Direct Neuronal Migration in Caenorhabditis elegans  

E-print Network

Voltage-Gated Calcium Channels Direct Neuronal Migration in Caenorhabditis elegans Tobey Tam for regulating the guidance of migrating neurons, yet the molecular mechanisms underlying this process for the accurate guidance of postembryonic neuronal migrations in the nematode Caenorhabditis elegans. In mutants

Schafer, William R.

232

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

PubMed Central

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

2013-01-01

233

Titin\\/connectin-related proteins in C. elegans : a review and new findings  

Microsoft Academic Search

Much is still unknown about mechanisms by which myofibrils assemble from their components, and how these precise structures are maintained in the face of repeated muscle activity. A number of labs, including ours, are exploiting the ability to analyze mutants in the nematode C. elegans to obtain insights into these questions. C. elegans is a particularly attractive organism in which

Tracey M. Ferrara; Denise B. Flaherty; Guy M. Benian

2005-01-01

234

Caenorhabditis elegans Aurora A kinase AIR-1 Is Required for Postembryonic Cell Divisions and Germline  

E-print Network

LETTER Caenorhabditis elegans Aurora A kinase AIR-1 Is Required for Postembryonic Cell Divisions the eukaryotic cell cycle. The Aurora kinases comprise a highly conserved family of serine/threonine kinases a sterile Caenorhabditis elegans mutant in which the majority of the locus encoding the Aurora A kinase air

Baillie, David

235

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

PubMed Central

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

Smith, R V; Davis, P J

1978-01-01

236

Neural Development Features: Spatio-Temporal Development of the Caenorhabditis elegans Neuronal Network  

Microsoft Academic Search

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.

Sreedevi Varier; Marcus Kaiser; Karl J. Friston

2011-01-01

237

Hybridization between Ischnura graellsii (Vander Linder) and I. elegans (Rambur) (Odonata: Coenagrionidae): are they different species?  

Microsoft Academic Search

Two closely related damselflies, Ischnura graellsii and I. elegans, were analysed for morphological differences and reproductive isolation in the north coast of Galicia (NW Spain). We compared animals from sympatric and allopatric localities, including I. elegans from Belgium and I. graellsii from southern Spain as pure allopatric populations. A set of morphometric characters were studied by means of multivariate discriminant

LILIANA MONETTI; ROSA ANA SANCHEZ-GUILLEN; ADOLFO CORDERO RIVERA

2002-01-01

238

Genetic analysis of sexual reproduction in the dendrophylliid coral Balanophyllia elegans  

Microsoft Academic Search

The ahermatypic scleractinian Balanophyllia elegans has served as a model of limited larval dispersal in an aclonal species. However, other species from the same family (Dendrophylliidae) produce larvae asexually, and closely connected polyps of B. elegans, potentially the result of asexual reproduction, are commonly observed in the field. Here, we use a combination of laboratory experiments, controlled crosses, and genetic

M. E. Hellberg; M. S. Taylor

2002-01-01

239

LETTER TO THE EDITOR Oligonucleotide-based targeted gene editing in C. elegans  

E-print Network

LETTER TO THE EDITOR Oligonucleotide-based targeted gene editing in C. elegans via the CRISPR/Cas9 Repeats (CRISPR)/ CRISPR-associated (Cas) system has emerged as a new powerful tool for genome [6], C. elegans [7-12], and plants [13]. In the widely used CRISPR/Cas9 system [2-4], the Cas9

Xue, Ding

240

First Descriptions of Immature Stages of the Weevils Bagous elegans, B. aliciae, and B. lutulosus.  

PubMed

Last-instar larvae of Bagous elegans (F.), Bagous aliciae Cmoluch, and Bagous lutulosus (Gyllenhal), and the pupa of B. elegans, are described and illustrated for the first time. Biology of these species is analyzed in association with larval morphology and feeding habits. Overall larval and pupal morphological diagnoses of the genus Bagous are updated. PMID:25347832

Gosik, Rafa?; Wanat, Marek

2014-01-01

241

Quantifying the Accuracy of C. elegans Image Analysis Jacob Graves and Roger Mailler  

E-print Network

- tis elegans; Simulation I. INTRODUCTION The nematode Caenorhabditis elegans is an important model values. To test our method, we took a popular analysis pipeline and varied the thinning algorithm it uses is in identifying different strains of worm based on their motion patterns over time. Since a complete neurological

Mailler, Roger

242

A Comparative Study of Fat Storage Quantitation in Nematode Caenorhabditis elegans Using Label and  

E-print Network

A Comparative Study of Fat Storage Quantitation in Nematode Caenorhabditis elegans Using Label of Massachusetts Medical School, Worcester, Massachusetts, United States of America Abstract The nematode) A Comparative Study of Fat Storage Quantitation in Nematode Caenorhabditis elegans Using Label and Label

Cheng, Ji-Xin

243

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

ERIC Educational Resources Information Center

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…

Amano, Hisayuki; Maruyama, Ichiro N.

2011-01-01

244

Title : Liquid C. elegans culture for the study of Burkholderia pathogenesis Authors : Vaughn Cooper1  

E-print Network

Title : Liquid C. elegans culture for the study of Burkholderia pathogenesis Authors : Vaughn Email: vaughn.cooper@unh.edu Abstract : The nematode C. elegans has been adopted as a key model system for the study of bacterial pathogenesis. The practical benefits of this system are notable: ease of culture

245

A Primary Culture System for Functional Analysis of C. elegans Neurons and Muscle Cells  

Microsoft Academic Search

C. elegans has provided important insights into neuromuscular system function and development. However, the animal's small size limits access to individual neurons and muscle cells for physiological, biochemical, and molecular study. We describe here primary culture methods that allow C. elegans embryonic cells to differentiate into neurons and muscle cells in vitro. Morphological, electrophysiological, and GFP reporter studies demonstrate that

Michael Christensen; Ana Estevez; Xiaoyan Yin; Rebecca Fox; Rebecca Morrison; Maureen McDonnell; Christina Gleason; David M. Miller III; Kevin Strange

2002-01-01

246

Dietary Restriction of Caenorhabditis elegans by Axenic Culture Reflects Nutritional Requirement for  

E-print Network

, are not limiting for life span. However, adding growth-arrested Escherichia coli as an additional food source--Caenorhabditis elegans--Escherichia coli--Aging--Axenic culture. DIETARY restriction (DR), the controlled reduction to subject C. elegans to DR. These include dilution of the Escherichia coli bacterial food source (8), use

Gems, David

247

Resistance to Bacillus thuringiensis Toxin in Caenorhabditis elegans from Loss of Fucose*  

E-print Network

Resistance to Bacillus thuringiensis Toxin in Caenorhabditis elegans from Loss of Fucose* Received elegans bre-1 gene was iso- lated in a screen for Bacillus thuringiensis toxin-resistant (bre) mutants by Bacillus thuringiensis are naturally occurring agents that are used for the control of insects that eat

Aroian, Raffi V.

248

Closing in on the C. elegans ORFeome by cloning TWINSCAN predictions  

E-print Network

Closing in on the C. elegans ORFeome by cloning TWINSCAN predictions Chaochun Wei,1 Philippe elegans was the first animal genome to be sequenced. Although considerable effort has been devoted of any multicellular organism. We then attempted to amplify, clone, and sequence 265 TWINSCAN

249

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

Microsoft Academic Search

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

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

2010-01-01

250

3-Ketoacyl thiolase delays aging of Caenorhabditis elegans and is required for lifespan extension  

E-print Network

about genes that normally act to delay aging and that when mutated cause premature aging (progeria). To seek such genes, we performed a genetic screen for C. elegans mutants that age prematurely. We found abnormalities characteristic of premature aging. These findings suggest that kat-1 acts to delay C. elegans

Horvitz, H. Robert

251

The Oogenic Germline Starvation Response in C. elegans Hannah S. Seidel1  

E-print Network

The Oogenic Germline Starvation Response in C. elegans Hannah S. Seidel1 *, Judith Kimble1,2 * 1 of Caenorhabditis elegans respond to starvation. To induce starvation, we removed food at 2 h intervals from very to produce viable progeny during starvation. Regardless of the bagging fate, starved animals showed two major

Sheridan, Jennifer

252

Ancestral roles of glia suggested by the nervous system of Caenorhabditis elegans  

E-print Network

Ancestral roles of glia suggested by the nervous system of Caenorhabditis elegans maxwell g. heiman and shai shaham The nematode Caenorhabditis elegans has a simple nervous system with glia restricted some glial activities may be fundamentally required for nervous system function. A priori, one might

Shaham, Shai

253

Successful reproduction of the introduced slider turtle(Trachemys scripta elegans) in the South of France  

Microsoft Academic Search

Massive importation of slider turtles (Trachemys scripta elegans) as a pet in France over the past few decades has been followed by the release of many of these turtles into natural environments. T. scripta elegans is now widely distributed in France. 2. This paper reports on the successful reproduction of this species in France, with confirmed production of both sexes

Antoine Cadi; Virginie Delmas; Anne-Caroline Prévot-Julliard; Pierre Joly; Claude Pieau; Marc Girondot

2004-01-01

254

Locally invasive cutaneous Apophysomyces elegans infection acquired from snapdragon patch test.  

PubMed

Apophysomyces elegans is an environmental fungus related to other well-known agents of zygomycosis. We report a case of locally invasive A elegans soft tissue infection resulting from the application of a skin patch to test for snapdragon sensitivity. The infection was limited to skin and soft tissue, and treatment consisted of local debridement and liposomal amphotericin B. Outcome was successful. PMID:12108611

Blair, Janis E; Fredrikson, Lorna J; Pockaj, Barbara A; Lucaire, Christina S

2002-07-01

255

Sinoorbital mucormycosis due to Apophysomyces elegans in immunocompetent individuals—an increasing trend  

Microsoft Academic Search

ObjectiveMucormycosis is a fatal infection of the immunocompromised individuals. Apophysomyces elegans is an unusual pathogen causing mucormycosis. It is unusual to affect the healthy individuals. We report 5 such cases of infection caused by A elegans in immunocompetent individuals.

Sridhara Suryanarayan Rao; Naresh K. Panda; Gilbert Pragache; Arunaloke Chakrabarti; K. Saravanan

2006-01-01

256

Programmed cell death in C. elegans: the genetic framework , Yi-Chun Wu2  

E-print Network

and molecular studies in C. elegans have led to the identification of many genes that function in different death C. elegans is a free living worm that feeds on bacteria and can be easily maintained perturbation in the cell death program can be identified and isolated. Genetic and phenotypic analyses

Xue, Ding

257

1722 Brief Communication The C. elegans homolog of the p53 tumor suppressor is required  

E-print Network

that the completion death. The DNA binding domain of CEP-1 is related of the C. elegans genomic sequence failed¨r Biochemie, Department of Cell C. elegans genome for distant p53 family members, weBiology, Am Klopferspitz, Boston, mouse, hamster, chicken, Xenopus, trout, squid, and mus- Massachusetts 02115, USA. sel, as well

Gartner, Anton

258

Automated analysis of embryonic gene expression with cellular resolution in C. elegans  

E-print Network

activity of each cell throughout development. A major goal of current biological research is to understand we had previously developed methods that allow automated computational tracing of the C. elegansAutomated analysis of embryonic gene expression with cellular resolution in C. elegans John Isaac

Cai, Long

259

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

ERIC Educational Resources Information Center

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,…

Roy, Nicole M.

2013-01-01

260

AI approach to optimal var control with fuzzy reactive loads  

SciTech Connect

This paper presents an artificial intelligence (AI) approach to the optimal reactive power (var) control problem. The method incorporates the reactive load uncertainty in optimizing the overall system performance. The artificial neural network (ANN) enhanced by fuzzy sets is used to determine the memberships of control variables corresponding to the given load values. A power flow solution will determine the corresponding state of the system. Since the resulting system state may not be feasible in real-time, a heuristic method based on the application of sensitivities in expert system is employed to refine the solution with minimum adjustments of control variables. Test cases and numerical results demonstrate the applicability of the proposed approach. Simplicity, processing speed and ability to model load uncertainties make this approach a viable option for on-line var control.

Abdul-Rahman, K.H.; Shahidehpour, S.M. [Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Electrical and Computer Engineering] [Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Electrical and Computer Engineering; Daneshdoost, M. [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Electrical and Computer Engineering] [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Electrical and Computer Engineering

1995-02-01

261

A genetic linkage map for watermelon derived from a testcross population: ( Citrullus lanatus var. citroides × C. lanatus var. lanatus ) × Citrullus colocynthis  

Microsoft Academic Search

A genetic linkage map was constructed for watermelon using a testcross population [Plant Accession Griffin 14113 (Citrullus lanatus var. citroides) 2 New Hampshire Midget (NHM; C. lanatus var. lanatus)] 2 U.S. Plant Introduction (PI) 386015 (Citrullus colocynthis). The map contains 141 randomly amplified polymorphic DNA (RAPD) markers produced by 78 primers, 27 inter-simple sequence repeat (ISSR) markers produced by 17

A. Levi; C. Thomas; T. Joobeur; X. Zhang; A. Davis

2002-01-01

262

Cylindrocarpon destructans VAR. destructans AND Neonectria discophora VAR. rubi ASSOCIATED WITH BLACK FOOT ROT ON BLACKBERRY (Rubus glaucus BENTH.) IN MÉRIDA, VENEZUELA  

Microsoft Academic Search

SUMMARY In a commercial blackberry (Rubus glaucus Benth.) field located at El Valle, Municipality Libertador, Mérida State, Venezuela, a black foot rot disease was detected in 1999. The causal agent was identified as Cylindrocarpon destructans var. destructans (teleo- morph=Neonectria radicicola var. radicicola). This pathogen attacks the roots and the crown, inducing die-back in canes. Symptoms simi- lar to those observed

Luis Cedeño; Chrystian Carrero; Kleyra Quintero; Henry Pino; Wilmer Espinoza

2004-01-01

263

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

264

Composition of the essential oil of Pogostemon travancoricus var. travancoricus.  

PubMed

The essential oil of Pogostemon travancoricus Bedd. var. travancoricus collected from the Agasthyamalai region of Tamil Nadu, India was analyzed by GC and GC-MS. The major components of the oil were bicyclogermacrene (16.0%), cis-calamenene (6.3%), germacrene B (11.1%), spathulenol (7.6%), viridiflorol (5.8%), alpha-cadinol (4.2%) and pogostone (9.9%). PMID:22428255

Murugan, Ramar; Mallavarapu, Gopal Rao

2012-01-01

265

The thermostability of purified isoperoxidases from Brassica oleracea VAR. gemmifera  

Microsoft Academic Search

The thermostabilities of four previously purified isoperoxidases from Brussels sprouts (Brassica oleracea VAR. gemmifera.)have been determined. The heating time periods selected (10 s – 0.5 min intervals) are comparable to those used during commercial blanching. Non-linear regression (NLR) equation fitting, using common goodness of fit criteria (low chi-squared value, high regression coefficient and low residuals) points to a mechanism of

J. L. Forsyth; R. K. Owusu Apenten; D. S. Robinson

1999-01-01

266

Allozyme Variation in Endangered Castanea pumila var. pumila  

PubMed Central

Allozyme genetic variation in 12 populations of the endangered Castanea pumila var. pumila (Allegheny chinkapin), sampled across the natural range of the species in the United States, was evaluated using 11 loci from seven enzyme systems. At the species level, the percentage of polymorphic loci (Ps) was 72·7 %, the mean number of alleles per locus (As) was 1·9, the mean number of alleles per polymorphic locus (APs) was 2·3, the effective number of alleles per locus (Aes) was 1·5 and the genetic diversity (Hes) was 0·296. At the population level, Pp = 49·2 %, Ap = 1·5, Aep = 1·4, APp = 2·1 and Hep = 0·21. Most of the allozyme variation (70 %) in C. pumila var. pumila occurred within populations. Wright’s gene flow rate [Nm(W)] was as low as 0·57. Population differentiation along the species range was not detected. Populations of C. pumila var. pumila in Florida had the most variable levels of genetic diversity, but populations in Virginia and Mississippi also showed high levels. Based on the results of this study, conservation management strategies are discussed. PMID:12829445

FU, YUQING; DANE, FENNY

2003-01-01

267

The transcription start site landscape of C. elegans  

PubMed Central

More than half of Caenorhabditis elegans pre-mRNAs lose their original 5? ends in a process termed “trans-splicing” in which the RNA extending from the transcription start site (TSS) to the site of trans-splicing of the primary transcript, termed the “outron,” is replaced with a 22-nt spliced leader. This complicates the mapping of TSSs, leading to a lack of available TSS mapping data for these genes. We used growth at low temperature and nuclear isolation to enrich for transcripts still containing outrons, applying a modified SAGE capture procedure and high-throughput sequencing to characterize 5? termini in this transcript population. We report from this data both a landscape of 5?-end utilization for C. elegans and a representative collection of TSSs for 7351 trans-spliced genes. TSS distributions for individual genes were often dispersed, with a greater average number of TSSs for trans-spliced genes, suggesting that trans-splicing may remove selective pressure for a single TSS. Upstream of newly defined TSSs, we observed well-known motifs (including TATAA-box and SP1) as well as novel motifs. Several of these motifs showed association with tissue-specific expression and/or conservation among six worm species. Comparing TSS features between trans-spliced and non-trans-spliced genes, we found stronger signals among outron TSSs for preferentially positioning of flanking nucleosomes and for downstream Pol II enrichment. Our data provide an enabling resource for both experimental and theoretical analysis of gene structure and function in C. elegans. PMID:23636945

Saito, Taro Leo; Hashimoto, Shin-ichi; Gu, Sam Guoping; Morton, J. Jason; Stadler, Michael; Blumenthal, Thomas; Fire, Andrew; Morishita, Shinichi

2013-01-01

268

Structural Properties of the Caenorhabditis elegans Neuronal Network  

PubMed Central

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. PMID:21304930

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

2011-01-01

269

Undulatory locomotion of finite filaments: lessons from Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

270

Global remodeling of nucleosome positions in C. elegans  

PubMed Central

Background Eukaryotic chromatin architecture is affected by intrinsic histone-DNA sequence preferences, steric exclusion between nucleosome particles, formation of higher-order structures, and in vivo activity of chromatin remodeling enzymes. Results To disentangle sequence-dependent nucleosome positioning from the other factors, we have created two high-throughput maps of nucleosomes assembled in vitro on genomic DNA from the nematode worm Caenorhabditis elegans. A comparison of in vitro nucleosome positions with those observed in a mixed-stage, mixed-tissue population of C. elegans cells reveals that in vivo sequence preferences are modified on the genomic scale. Indeed, G/C dinucleotides are predicted to be most favorable for nucleosome formation in vitro but not in vivo. Nucleosome sequence read coverage in vivo is distinctly lower in chromosome arms than in central regions; the observed changes in apparent nucleosome sequence specificity, likely due to genome-wide chromatin remodeler activity, contribute to the formation of these megabase-scale chromatin domains. We also observe that the majority of well-positioned in vivo nucleosomes do not occupy thermodynamically favorable sequences observed in vitro. Finally, we find that exons are intrinsically more amenable to nucleosome formation compared to introns. Nucleosome occupancy of introns and exons consistently increases with G/C content in vitro but not in vivo, in agreement with our observation that G/C dinucleotide enrichment does not strongly promote in vivo nucleosome formation. Conclusions Our findings highlight the importance of both sequence specificity and active nucleosome repositioning in creating large-scale chromatin domains, and the antagonistic roles of intrinsic sequence preferences and chromatin remodelers in C. elegans. Sequence read data has been deposited into Sequence Read Archive (http://www.ncbi.nlm.nih.gov/sra; accession number SRA050182). Additional data, software and computational predictions are available on the Nucleosome Explorer website (http://nucleosome.rutgers.edu). PMID:23622142

2013-01-01

271

The olfactory signal transduction for attractive odorants in Caenorhabditis elegans.  

PubMed

Olfaction in Caenorhabditis elegans is a versatile and sensitive strategy to seek food and avoid danger by sensing volatile chemicals emitted by the targets. The ability to sense attractive odor is mainly accomplished by the AWA and AWC neurons. Previous studies have shown the components of the olfaction signal pathway in these two amphid chemosensory neurons, but integration of the individual signaling components requires further elucidation. Here we review the progresses in our understanding of signal pathways for attractive olfaction involving AWA and AWC neurons, and discuss how the different signal molecules might employ the common molecular cascades to transduce the olfactory system and guide behavior in each neuron. PMID:24189094

Zhang, Chunmei; Yan, Jinyuan; Chen, Yao; Chen, Chunyan; Zhang, Keqin; Huang, Xiaowei

2014-01-01

272

Caenorhabditis elegans - A model system for space biology studies  

NASA Technical Reports Server (NTRS)

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.

Johnson, Thomas E.; Nelson, Gregory A.

1991-01-01

273

Diurnal ventilatory patterns in the garter snake, Thamnophis elegans  

Microsoft Academic Search

Garter snakes,Thamnophis elegans, were entrained to a 14L (06.30–20.30 h) 10D (20.30–06.30 h) cycle for five weeks at 25 °C. Following entrainment, simultaneous measurements of ventilation and oxygen uptake were made. Pulmonary oxygen uptake (\\u000a$$\\\\dot V_{O_2 } $$\\u000a) exhibited a diurnal rhythm with minimum values of\\u000a$$\\\\dot V_{O_2 } $$\\u000a occurring during 10D. The diurnal rhythm persisted during

James W. Hicks; Marvin L. Riedesel

1983-01-01

274

Google matrix analysis of C.elegans neural network  

NASA Astrophysics Data System (ADS)

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.

Kandiah, V.; Shepelyansky, D. L.

2014-05-01

275

Google matrix analysis of C.elegans neural network  

E-print Network

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.

Kandiah, Vivek

2013-01-01

276

Dissecting and recording from the C. Elegans neuromuscular junction.  

PubMed

Neurotransmission is the process by which neurons transfer information via chemical signals to their post-synaptic targets, on a rapid time scale. This complex process requires the coordinated activity of many pre- and post-synaptic proteins to ensure appropriate synaptic connectivity, conduction of electrical signals, targeting and priming of secretory vesicles, calcium sensing, vesicle fusion, localization and function of postsynaptic receptors and finally, recycling mechanisms. As neuroscientists it is our goal to elucidate which proteins function in each of these steps and understand their mechanisms of action. Electrophysiological recordings from synapses provide a quantifiable read out of the underlying electrical events that occur during synaptic transmission. By combining this technique with the powerful array of molecular and genetic tools available to manipulate synaptic proteins in C. elegans, we can analyze the resulting functional changes in synaptic transmission. The C. elegans NMJs formed between motor neurons and body wall muscles control locomotion, therefore, mutants with uncoordinated locomotory phenotypes (known as unc s) often perturb synaptic transmission at these synapses (1). Since unc mutants are maintained on a rich supply of a bacterial food source, they remain viable as long as they retain some pharyngeal pumping ability to ingest food. This, together with the fact that C. elegans exist as hermaphrodites, allows them to pass on mutant progeny without the need for elaborate mating behaviors. These attributes, coupled with our recent ability to record from the worms NMJs (2 3) make this an excellent model organism in which to address precisely how unc mutants impact neurotransmission. The dissection method involves immobilizing adult worms using a cyanoacrylic glue in order to make an incision in the worm cuticle exposing the NMJs. Since C. elegans adults are only 1 mm in length the dissection is performed with the use of a dissecting microscope and requires excellent hand-eye coordination. NMJ recordings are made by whole-cell voltage clamping individual body wall muscle cells and neurotransmitter release can be evoked using a variety of stimulation protocols including electrical stimulation, light-activated channel-rhodopsin-mediated depolarization (4) and hyperosmotic saline, all of which will be briefly described. PMID:19488020

Richmond, Janet

2009-01-01

277

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

PubMed

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-specific cilia with the well-studied cilia of the amphid and phasmid neurons has allowed identification of molecules that specialize the male cilia. We will discuss the molecules that shape the male-specific cilia. The cell biology of cilia in male-specific neurons demonstrates that C. elegans can provide an excellent model of ciliary specialization. PMID:24977333

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

2014-09-01

278

[Necrotizing fasciitis in an immunocompetent patient caused by Apophysomyces elegans].  

PubMed

A case study is presented of a 7-year-old boy, seriously injured in a car accident, who developed a fatal infection due to Aphophysomyces elegans--a mold of the Mucoracea family. Fungal invasion was initially manifested by a spotted wound in the left lumbar region which developed into a necrotizing fasciitis. Later this progressed to the right lumbar area, including the gluteus and the corresponding flank. Antimycotic treatment proved ineffective, and the child died 8 weeks after the accident. Other cases due to this fungus are reviewed. PMID:15551876

Ruiz, Carmen Elena; Arango, Myrtha; Correa, Ana Lucía; López, Luz Saider; Restrepo, Angela

2004-09-01

279

Severe osteomyelitis due to the zygomycete Apophysomyces elegans.  

PubMed Central

We describe a previously healthy 69-year-old man presenting with osteomyelitis of the humerus due to the zygomycete Apophysomyces elegans. The infection was acquired in Aruba, The Netherlands Antilles. The skin provided the most likely portal of entry, although there was no history of a traumatic inoculation. The patient had no history of diabetes, and no underlying immune defects were found. Despite treatment with 7.9 g of amphotericin B, an interthoracoscapular amputation proved necessary to curtail the rapid spread of the fungus in this immunocompetent host. Images PMID:7883908

Meis, J F; Kullberg, B J; Pruszczynski, M; Veth, R P

1994-01-01

280

Severe osteomyelitis due to the zygomycete Apophysomyces elegans.  

PubMed

We describe a previously healthy 69-year-old man presenting with osteomyelitis of the humerus due to the zygomycete Apophysomyces elegans. The infection was acquired in Aruba, The Netherlands Antilles. The skin provided the most likely portal of entry, although there was no history of a traumatic inoculation. The patient had no history of diabetes, and no underlying immune defects were found. Despite treatment with 7.9 g of amphotericin B, an interthoracoscapular amputation proved necessary to curtail the rapid spread of the fungus in this immunocompetent host. PMID:7883908

Meis, J F; Kullberg, B J; Pruszczynski, M; Veth, R P

1994-12-01

281

Apophysomyces elegans causing acute otogenic cervicofacial zygomycosis involving salivary glands.  

PubMed

Zygomycosis is an invasive, life threatening fungal infection that usually affects immunocompromised hosts. In the head and neck region, rhino-orbito-cerebral zygomycosis is more common than the cervicofacial variety. We report the first case of otogenic cervicofacial zygomycosis caused by Apophysomyces elegans involving the salivary glands, an uncommon site of infection. The case began after a trivial trauma in a diabetic patient and despite surgical debridement and liposomal amphotericin B therapy, the patient died due to extensive involvement and metabolic/hemodynamic complications. PMID:17654273

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

2007-08-01

282

Isolation of Specific Neurons from C. elegans Larvae for Gene Expression Profiling  

PubMed Central

Background 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. Methods and Results 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. Significance 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. PMID:25372608

Spencer, W. Clay; McWhirter, Rebecca; Miller, Tyne; Strasbourger, Pnina; Thompson, Owen; Hillier, LaDeana W.; Waterston, Robert H.; Miller, David M.

2014-01-01

283

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

PubMed Central

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

2012-01-01

284

Generation of Expressed Sequence Tags and development of microsatellite markers for Castanopsis sieboldii var. sieboldii (Fagaceae)  

Microsoft Academic Search

– \\u000a \\u000a • Castanopsis sieboldii var. sieboldii is an evergreen broadleaved canopy tree that grows on Honshu, Shikoku and Kyushu Islands in Japan. A closely-related, hybridizing,\\u000a congener species, C. cuspidata var. cuspidata, has different leaf epidermis structure and different seed nuts morphology compared to C. sieboldii var. sieboldii. Furthermore, the habitats in which the two species grow often indicate different water

Saneyoshi Ueno; Kyoko Aoki; Yoshihiko Tsumura

2009-01-01

285

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

PubMed Central

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

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

2010-01-01

286

Simple method of inducing sporulation by Apophysomyces elegans and Saksenaea vasiformis.  

PubMed

Apophysomyces elegans and Saksenaea vasiformis are notorious for their failure to sporulate on routine media. Agar blocks, permeated with the mycelia of A. elegans and S. vasiformis, were cut aseptically from 7-day-old colonies grown on Sabouraud dextrose agar and transferred to plates containing 20 ml of sterile distilled water supplemented with 0.2 ml of 10% filter-sterilized yeast extract solution. When the plates were incubated at 37 degrees C, all 5 isolates of A. elegans and all 10 isolates of S. vasiformis produced abundant, characteristic sporangia within 7 to 10 days. The method is simple to use and yields consistent results. PMID:3183029

Padhye, A A; Ajello, L

1988-09-01

287

Selenium induces cholinergic motor neuron degeneration in Caenorhabditis elegans  

PubMed Central

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. PMID:22560997

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

2012-01-01

288

Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans.  

PubMed

After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2-3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death. PMID:24317200

Sun, C-L; Kim, E; Crowder, C M

2014-04-01

289

PTL-1 regulates neuronal integrity and lifespan in C. elegans.  

PubMed

Protein with tau-like repeats (PTL-1) is the sole Caenorhabditis elegans homolog of tau and MAP2, which are members of the mammalian family of microtubule-associated proteins (MAPs). In mammalian neurons, tau and MAP2 are segregated, with tau being mainly localised to the axon and MAP2 mainly to the dendrite. In particular, tau plays a crucial role in pathology, as elevated levels lead to the formation of tau aggregates in many neurodegenerative conditions including Alzheimer's disease. We used PTL-1 in C. elegans to model the biological functions of a tau-like protein without the complication of functional redundancy that is observed among the mammalian MAPs. Our findings indicate that PTL-1 is important for the maintenance of neuronal health as animals age, as well as in the regulation of whole organism lifespan. In addition, gene dosage of PTL-1 is crucial because variations from wild-type levels are detrimental. We also observed that human tau is unable to robustly compensate for loss of PTL-1, although phenotypes observed in tau transgenic worms are dependent on the presence of endogenous PTL-1. Our data suggest that some of the effects of tau pathology result from the loss of physiological tau function and not solely from a toxic gain-of-function due to accumulation of tau. PMID:23525010

Chew, Yee Lian; Fan, Xiaochen; Götz, Jürgen; Nicholas, Hannah R

2013-05-01

290

Propulsion of C. elegans crawling on a wet surface  

NASA Astrophysics Data System (ADS)

Nematodes, such as soil-dwelling worms C. elegans, propel themselves by producing undulatory body motion. An important requirement for effective propulsion is to have large transverse and small longitudinal friction forces acting on a crawling worm. Recently, Sauvage et al. have shown that soft-lubrication forces between the worm body and a moist supporting substrate can produce, at most, the transverse friction coefficient twice as large as the longitudinal friction coefficient (and this ratio is too small for efficient propulsion). Here we show that hydrodynamic resistance of the fluid in liquid film adjacent to the worm body can generate significantly larger transverse friction, which moreover, is wavelength dependent. By modeling the worm as a long chain of spheres in Hele--Shaw flow, we have determined the optimal wavelength and amplitude of the undulatory motion that optimizes propulsion efficiency for a given rate of energy dissipation. The optimal worm shape qualitatively agrees with our experimental observations of C. elegans crawling in moist environments.

Bilbao, A.; Alavalapadu, A.; Khan, Z. S.; Salomon, D. E.; Vanapalli, S. A.; Rumbaugh, K.; Blawzdziewicz, J.

2011-11-01

291

3-D Worm Tracker for Freely Moving C. elegans  

PubMed Central

The manner in which the nervous system regulates animal behaviors in natural environments is a fundamental issue in biology. To address this question, C. elegans has been widely used as a model animal for the analysis of various animal behaviors. Previous behavioral assays have been limited to two-dimensional (2-D) environments, confining the worm motion to a planar substrate that does not reflect three-dimensional (3-D) natural environments such as rotting fruits or soil. Here, we develop a 3-D worm tracker (3DWT) for freely moving C. elegans in 3-D environments, based on a stereoscopic configuration. The 3DWT provides us with a quantitative trajectory, including the position and movement direction of the worm in 3-D. The 3DWT is also capable of recording and visualizing postures of the moving worm in 3-D, which are more complex than those in 2-D. Our 3DWT affords new opportunities for understanding the nervous system function that regulates animal behaviors in natural 3-D environments. PMID:23437394

Kwon, Namseop; Pyo, Jaeyeon; Lee, Seung-Jae; Je, Jung Ho

2013-01-01

292

Outcrossing and the Maintenance of Males within C. elegans Populations  

PubMed Central

Caenorhabditis elegans is an androdioecious nematode with both hermaphrodites and males. Although males can potentially play an important role in avoiding inbreeding and facilitating adaptation, their existence is evolutionarily problematic because they do not directly generate offspring in the way that hermaphrodites do. This review explores how genetic, population genomic, and experimental evolution approaches are being used to address the role of males and outcrossing within C. elegans. Although theory suggests that inbreeding depression and male mating ability should be the primary determinants of male frequency, this has yet to be convincingly confirmed experimentally. Genomic analysis of natural populations finds that outcrossing occurs at low, but not negligible levels, and that observed patterns of linkage disequilibrium consistent with strong selfing may instead be generated by natural selection against outcrossed progeny. Recent experimental evolution studies suggest that males can be maintained at fairly high levels if populations are initiated with sufficient genetic variation and/or subjected to strong natural selection via a change in the environment. For example, as reported here, populations adapting to novel laboratory rearing and temperature regimes maintain males at frequencies from 5% to 40%. Laboratory and field results still await full reconciliation, which may be facilitated by identifying the loci underlying among-strain differences in mating system dynamics. PMID:20212008

2010-01-01

293

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

PubMed

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. PMID:25130468

Suda, Hitoshi

2014-09-12

294

Reverse genetics by chemical mutagenesis in Caenorhabditis elegans.  

PubMed

Traditional reverse genetics on yeast, mice and other organisms uses homologous recombination with transgenic DNA to interrupt a target gene. Here we report that target-selected gene inactivation can be be achieved in Caenorhabditis elegans with the use of chemical mutagens. We use PCR to selectively visualize deletions in genes of interest; the method is sensitive enough to permit detection of a single mutant among more than 15,000 wild types. A permanent frozen mutant collection of more than a million mutagenized animals has been established, and deletion mutants of several G-protein genes were isolated from it. The approach is suitable to be scaled up for systematic inactivation of all 17,000 C. elegans genes. Because it requires no transgenesis or cell culturing, it may also be applicable to small organisms usually considered to be outside the realm of reverse genetics (for example, other nematodes and insects). Any sequenced gene in any organism that can be handled in very large numbers can possibly be targeted in this way. PMID:9288111

Jansen, G; Hazendonk, E; Thijssen, K L; Plasterk, R H

1997-09-01

295

Fluorescent visualization of germline apoptosis in living Caenorhabditis elegans.  

PubMed

Visualization of apoptosis using fluorescent tools is quite straightforward in living Caenorhabditis elegans. Several transgenic lines are available that mark dying cells with fluorescent proteins, making it possible to quantify kinetics at various stages of the apoptotic process. Proteins required for the engulfment of cell corpses are particularly useful for detecting early apoptotic stages using this approach. For example, expression of the engulfment protein CED-1 fused to green fluorescent protein (CED-1::GFP) creates a halo around cells during early apoptosis, before their refractile morphology can be detected by differential interference contrast (DIC) optics. In addition, vital dyes such as acridine orange (AO) and SYTO-12 are selectively retained in apoptotic cells and can be used to visualize apoptosis in the germlines of living animals. It is also possible to use vital dyes in combination with transgenic strains expressing fluorescent markers of cell corpses to examine, in detail, multiple stages of apoptosis in vivo. Because of the high optical contrast of fluorescent reagents, apoptosis can be visualized even at low magnification, facilitating the use of screening platforms to identify apoptosis regulators. This protocol describes multiple uses of fluorescent reagents for visualization of germline apoptosis in living C. elegans, including AO staining, time-course studies using fluorescent proteins, and low-throughput screening of cell death genes using RNA interference (RNAi). PMID:24692492

Lant, Benjamin; Derry, W Brent

2014-04-01

296

Manganese disturbs metal and protein homeostasis in Caenorhabditis elegans.  

PubMed

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

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

2014-10-01

297

Mitoflash frequency in early adulthood predicts lifespan in Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

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.

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

298

Microbeam irradiation of C. elegans nematode in microfluidic channels.  

PubMed

To perform high-throughput studies on the biological effects of ionizing radiation in vivo, we have implemented a microfluidic tool for microbeam irradiation of Caenorhabditis elegans. The device allows the immobilization of worms with minimal stress for a rapid and controlled microbeam irradiation of multiple samples in parallel. Adapted from an established design, our microfluidic clamp consists of 16 tapered channels with 10-?m-thin bottoms to ensure charged particle traversal. Worms are introduced into the microfluidic device through liquid flow between an inlet and an outlet, and the size of each microchannel guarantees that young adult worms are immobilized within minutes without the use of anesthesia. After site-specific irradiation with the microbeam, the worms can be released by reversing the flow direction in the clamp and collected for analysis of biological endpoints such as repair of radiation-induced DNA damage. For such studies, minimal sample manipulation and reduced use of drugs such as anesthetics that might interfere with normal physiological processes are preferable. By using our microfluidic device that allows simultaneous immobilization and imaging for irradiation of several whole living samples on a single clamp, here we show that 4.5-MeV proton microbeam irradiation induced DNA damage in wild-type C. elegans, as assessed by the formation of Rad51 foci that are essential for homologous repair of radiation-induced DNA damage. PMID:23942865

Buonanno, M; Garty, G; Grad, M; Gendrel, M; Hobert, O; Brenner, D J

2013-11-01

299

Microbeam Irradiation of C. elegans Nematode in Microfluidic Channels  

PubMed Central

To perform high-throughput studies on the biological effects of ionizing radiation in vivo, we have implemented a microfluidic tool for microbeam irradiation of Caenorhabditis elegans. The device allows the immobilization of worms with minimal stress for a rapid and controlled microbeam irradiation of multiple samples in parallel. Adapted from an established design, our microfluidic clamp consists of 16 tapered channels with 10-?m thin bottoms to ensure charged particle traversal. Worms are introduced into the microfluidic device through liquid flow between an inlet and an outlet and the size of each microchannel guarantees that young adult worms are immobilized within minutes without the use of anesthesia. After site-specific irradiation with the microbeam, the worms can be released by reversing the flow direction in the clamp and collected for analysis of biological endpoints such as repair of radiation-induced DNA damage. For such studies, minimal sample manipulation and reduced use of drugs such as anesthetics that might interfere with normal physiological processes are preferable. By using our microfluidic device that allows simultaneous immobilization and imaging for irradiation of several whole living samples on a single clamp, here we show that 4.5 MeV proton microbeam irradiation induced DNA damage in wild type C.elegans, as assessed by the formation of Rad-51 foci that are essential for homologous repair of radiation-induced DNA damage. PMID:23942865

Buonanno, M.; Garty, G.; Grad, M.; Gendrel, M.; Hobert, O.; Brenner, D.J.

2013-01-01

300

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

PubMed

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. PMID:16903785

Chang, Andy J; Chronis, Nikolas; Karow, David S; Marletta, Michael A; Bargmann, Cornelia I

2006-09-01

301

Imprinting Capacity of Gamete Lineages in Caenorhabditis elegans  

PubMed Central

We have observed a gamete-of-origin imprinting effect in C. elegans using a set of GFP reporter transgenes. From a single progenitor line carrying an extrachromosomal unc-54::gfp transgene array, we generated three independent autosomal integrations of the unc-54::gfp transgene. The progenitor line, two of its three integrated derivatives, and a nonrelated unc-119:gfp transgene exhibit an imprinting effect: single-generation transmission of these transgenes through the male germline results in ?1.5- to 2.0-fold greater expression than transmission through the female germline. There is a detectable resetting of the imprint after passage through the opposite germline for a single generation, indicating that the imprinted status of the transgenes is reversible. In cases where the transgene is maintained in either the oocyte lineage or sperm lineage for multiple, consecutive generations, a full reset requires passage through the opposite germline for several generations. Taken together, our results indicate that C. elegans has the ability to imprint chromosomes and that differences in the cell and/or molecular biology of oogenesis and spermatogenesis are manifest in an imprint that can persist in both somatic and germline gene expression for multiple generations. PMID:15944356

Sha, Ky; Fire, Andrew

2005-01-01

302

Fatal Apophysomyces elegans infection transmitted by deceased donor renal allografts.  

PubMed

Two patients developed renal mucormycosis following transplantation of kidneys from the same donor, a near-drowning victim in a motor vehicle crash. Genotypically, indistinguishable strains of Apophysomyces elegans were recovered from both recipients. We investigated the source of the infection including review of medical records, environmental sampling at possible locations of contamination and query for additional cases at other centers. Histopathology of the explanted kidneys revealed extensive vascular invasion by aseptate, fungal hyphae with relative sparing of the renal capsules suggesting a vascular route of contamination. Disseminated infection in the donor could not be definitively established. A. elegans was not recovered from the same lots of reagents used for organ recovery or environmental samples and no other organ transplant-related cases were identified. This investigation suggests either isolated contamination of the organs during recovery or undiagnosed disseminated donor infection following a near-drowning event. Although no changes to current organ recovery or transplant procedures are recommended, public health officials and transplant physicians should consider the possibility of mucormycosis transmitted via organs in the future, particularly for near-drowning events. Attention to aseptic technique during organ recovery and processing is re-emphasized. PMID:20883549

Alexander, B D; Schell, W A; Siston, A M; Rao, C Y; Bower, W A; Balajee, S A; Howell, D N; Moore, Z S; Noble-Wang, J; Rhyne, J A; Fleischauer, A T; Maillard, J M; Kuehnert, M; Vikraman, D; Collins, B H; Marroquin, C E; Park, B J

2010-09-01

303

Characterization of mitochondrial thioredoxin reductase from C. elegans  

SciTech Connect

Thioredoxin reductase catalyzes the NADPH-dependent reduction of the catalytic disulfide bond of thioredoxin. In mammals and other higher eukaryotes, thioredoxin reductases contain the rare amino acid selenocysteine at the active site. The mitochondrial enzyme from Caenorhabditis elegans, however, contains a cysteine residue in place of selenocysteine. The mitochondrial C. elegans thioredoxin reductase was cloned from an expressed sequence tag and then produced in Escherichia coli as an intein-fusion protein. The purified recombinant enzyme has a k {sub cat} of 610 min{sup -1} and a K {sub m} of 610 {mu}M using E. coli thioredoxin as substrate. The reported k {sub cat} is 25% of the k {sub cat} of the mammalian enzyme and is 43-fold higher than a cysteine mutant of mammalian thioredoxin reductase. The enzyme would reduce selenocysteine, but not hydrogen peroxide or insulin. The flanking glycine residues of the GCCG motif were mutated to serine. The mutants improved substrate binding, but decreased the catalytic rate.

Lacey, Brian M. [Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT 05405 (United States); Hondal, Robert J. [Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT 05405 (United States)]. E-mail: Robert.Hondal@uvm.edu

2006-08-04

304

Nitric oxide production by the differentiating xylem of Zinnia elegans.  

PubMed

Nitric oxide (NO) is currently regarded as a signal molecule involved in plant cell differentiation and programmed cell death. Here, we investigated NO production in the differentiating xylem of Zinnia elegans by confocal laser scanning microscopy to answer the question of whether NO is produced during xylem differentiation. Results showed that NO production was mainly located in both phloem and xylem regardless of the cell differentiation status. However, there was evidence for a spatial NO gradient inversely related to the degree of xylem differentiation and a protoplastic NO burst was associated with the single cell layer of pro-differentiating thin-walled xylem cells. Confirmation of these results was obtained using trans-differentiating Z. elegans mesophyll cells. In this system, the scavenging of NO by means of 2-phenyl-4,4,5,5-tetramethyl imidazoline-1-oxyl-3-oxide (PTIO) inhibits tracheary element differentiation but increases cell viability. These results suggest that plant cells, which are just predetermined to irreversibly trans-differentiate in xylem elements, show a burst in NO production, this burst being sustained as long as secondary cell wall synthesis and cell autolysis are in progress. PMID:15720627

Gabaldón, Carlos; Gómez Ros, Laura V; Pedreño, María A; Ros Barceló, A

2005-01-01

305

Ethylene stimulates tracheary element differentiation in Zinnia elegans cell cultures.  

PubMed

The exact role of ethylene in xylogenesis remains unclear, but the Zinnia elegans cell culture system provides an excellent model with which to study its role during the differentiation of tracheary elements (TEs) in vitro. Here, we analysed ethylene homeostasis and function during Z. elegans TE differentiation using biochemical, molecular and pharmacological methods. Ethylene evolution was confined to specific stages of TE differentiation. It was found to peak at the time of TE maturation and to correlate with the activity of the ethylene biosynthetic 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase. The ethylene precursor ACC was exported and accumulated to high concentrations in the extracellular medium, which also displayed a high capacity to convert ACC into ethylene. The effects of adding inhibitors of the ethylene biosynthetic ACC synthase and ACC oxidase enzymes to the TE cultures demonstrated for the first time strict dependence of TE differentiation on ethylene biosynthesis and a stimulatory effect of ethylene on the rate of TE differentiation. In a whole-plant context, our results suggest that ethylene synthesis occurs in the apoplast of the xylem elements and that ethylene participates, in a paracrine manner, in the control of the cambial stem cell pool size during secondary xylem formation. PMID:21219334

Pesquet, Edouard; Tuominen, Hannele

2011-04-01

306

Phylogenetic analysis of cryptic speciation in the polychaete Pygospio elegans  

PubMed Central

Development in marine invertebrate species can take place through a variety of modes and larval forms, but within a species, developmental mode is typically uniform. Poecilogony refers to the presence of more than one mode of development within a single species. True poecilogony is rare, however, and in some cases, apparent poecilogony is actually the result of variation in development mode among recently diverged cryptic species. We used a phylogenetic approach to examine whether poecilogony in the marine polychaete worm, Pygospio elegans, is the result of cryptic speciation. Populations of worms identified as P. elegansooded, and intermediate larvae; these modes are found both within and among populations. We examined sequence variation among partial mitochondrial cytochrome c oxidase subunit I sequences obtained for 279 individual worms sampled across broad geographic and environmental scales. Despite a large number of unique haplotypes (121 haplotypes from 279 individuals), sequence divergence among European samples was low (1.7%) with most of the sequence variation observed within populations, relative to the variation among regions. More importantly, we observed common haplotypes that were widespread among the populations we sampled, and the two most common haplotypes were shared between populations differing in developmental mode. Thus, our results support an earlier conclusion of poecilogony in P elegans. In addition, predominantly planktonic populations had a larger number of population-specific low-frequency haplotypes. This finding is largely consistent with interspecies comparisons showing high diversity for species with planktonic developmental modes in contrast to low diversity in species with brooded developmental modes. PMID:22837844

Kesaniemi, J E; Rawson, P D; Lindsay, S M; Knott, K E

2012-01-01

307

Our evolving view of Wnt signaling in C. elegans  

PubMed Central

In this commentary, we discuss how our recent paper by Yang et al. contributes a new wrinkle to the already somewhat curious Wnt signaling pathway in C. elegans. We begin with a historical perspective on the Wnt pathway in the worm, followed by a summary of the key salient point from Yang et al., 2011, namely demonstration of mutually inhibitory binding of a ?-catenin SYS-1 to the N-terminus and another ?-catenin WRM-1 to the C-terminus of the TCF protein POP-1, and a plausible structural explanation for these differential binding specificities. The mutually inhibitory binding creates one population of POP-1 that is bound by WRM-1, phosphorylated by the NLK kinase and exported from the nucleus, and another bound by coactivator SYS-1 that remains in the nucleus. We speculate on the evolutionary history of the four ?-catenins in C. elegans and suggest a possible link between multiple ?-catenin gene duplications and the requirement to reduce nuclear POP-1 levels to activate Wnt target genes. PMID:24058829

Robertson, Scott M.; Lin, Rueyling

2012-01-01

308

E(var)3-9 of Drosophila melanogaster encodes a zinc finger protein.  

PubMed

The importance of a gene's natural chromatin environment for its normal expression is poignantly illustrated when a change in chromosome position results in variable gene repression, such as is observed in position effect variegation (PEV) when the Drosophila melanogaster white (omega) gene is juxtaposed with heterochromatin. The Enhancer of variegation 3-9 [E(var)3-9] gene was one of over a hundred loci identified in screens for mutations that dominantly modify PEV. Haploinsufficiency for E(var)3-9 enhances omegam4 variegation, as would be expected from increased heterochromatin formation. To clarify the role of E(var)3-9 in chromosome structure, the gene has been cloned and its mutant alleles characterized. The involvement of E(var)3-9 in structure determination was supported by its reciprocal effects on euchromatic and heterochromatic PEV; E(var)3-9 mutations increased expression of a variegating heterochromatic gene in two tissue types. E(var)3-9 mutations also had a recessive phenotype, maternal effect lethality, which implicated E(var)3-9 function in an essential process during embryogenesis. Both phenotypes of E(var)3-9 mutations were consistent with its proposed function in promoting normal chromosome structure. The cloning of E(var)3-9 by classical genetic methods revealed that it encodes a protein with multiple zinc fingers, but otherwise novel sequence. PMID:17660546

Weiler, Karen S

2007-09-01

309

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

PubMed Central

Cancers typically harbour several mutant forms of key cellular genes that contribute to its complex phenotype. Our lab has previously identified gain-of-function mutations in some of the receptor tyrosine kinases such as c-Met in lung cancer. In order to investigate the mutant gene in the context of a whole organism, the current choice of in vivo model is limited to the mouse. To rapidly screen the functional aspects of mutant forms of c-Met detected in lung cancer, we used the nematode C. elegans as the model organism. Transgenic worms were generated that harbour wild type or the frequently seen mutant forms of c-Met in lung cancer (c-MetR988C and c-MetT1010I). Expression of the mutant human c-Met forms in C. elegans consistently resulted in significantly low fecundity and abnormal vulval development characterized by hyperplasia. Interestingly, exposure of c-Met mutant transgenic worms to nicotine resulted in enhanced abnormal vulval development, fecundity, and locomotion. Our studies provide first evidence that human c-Met mutations can be studied in C. elegans, and that carcinogens can enhance mutant c-Met function expressed in C. elegans transgenic animals. We therefore propose the use of C. elegans as a model to rapidly assess the role of cancer specific gene mutations in the context of a whole organism. PMID:18340114

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

2008-01-01

310

A Comparative Evaluation of EM on Soil Quality and Fresh Yield of Brassica oleracea var. acephala Grown on Orangeburg Loamy Sand Soil  

E-print Network

A Comparative Evaluation of EM on Soil Quality and Fresh Yield of Brassica oleracea var. acephala, increased fresh leaf yield of collard greens (Brassica oleracea var. acephala)upto48%greaterthanthecontrol and traditional nu- trientsourcesonfreshleafyieldofcollardgreens(Brassica oleracea var. acephala

Jawitz, James W.

311

X chromosome repression by localization of the C. elegans dosage compensation machinery to sites  

E-print Network

expression of X-linked genes between the sexes is typically lethal. In C. elegans, XX hermaphrodites halve bacteria to humans8. Although the molecular parallels to mitotic chromosome condensation broadly suggest

Lieb, Jason

312

Receptors and Other Signaling Proteins Required for Serotonin Control of Locomotion in Caenorhabditis elegans  

E-print Network

A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans ...

Gustafson, Megan A.

313

C. elegans integrates food, stress, and hunger signals to coordinate motor activity  

E-print Network

In the presence of a bacterial food source, the small nematode C. elegans greatly reduces its rate of locomotion. While mechanical agitation greatly stimulates the locomotion of well-fed animals on bacteria, it does not ...

Omura, Daniel Togo

2008-01-01

314

Profiling the Anaerobic Response of C. elegans Using GC-MS  

PubMed Central

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. PMID:23029411

Bokov, Alex F.; Hakala, Kevin W.; Weintraub, Susan T.; Rea, Shane L.

2012-01-01

315

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

PubMed

The pheromone drop test is a simple and robust behavioral assay to quantify acute avoidance of pheromones in C. elegans, and the suppression of avoidance by attractive pheromones. In the pheromone drop test, water-soluble C. elegans pheromones are individually applied to animals that are freely moving on a large plate. Upon encountering a repellent, each C. elegans animal may or may not try to escape by making a long reversal. The fraction of animals that make a long reversal response indicates the repulsiveness of a given pheromone to a specific genotype/strain of C. elegans. Performing the drop test in the presence of bacterial food enhances the avoidance response to pheromones. Attraction to pheromones can be assayed by the suppression of reversals to repulsive pheromones or by the suppression of the basal reversal rate to buffer. PMID:24014370

Jang, Heeun; Bargmann, Cornelia I

2013-01-01

316

Analysis of the swimming-to-crawling transition of Caenorhabditis elegans in viscous fluid  

E-print Network

The locomotory behavior of the nematode Caenorhabditis elegans is often characterized by two distinct gaits - swimming when in fluids and crawling when on surfaces. Swimming is characterized by about a twice greater ...

Kawai, Risa

2008-01-01

317

A Cholinergic Sensory-Motor Circuit Controls the Male Copulation Behavior in C. elegans  

E-print Network

elucidated in any animal. During mating, the C. elegans male cloaca is positioned over the hermaphrodite’s vulva as he attempts to insert his copulatory spicules repetitively. Rhythmic spicule thrusts cease when insertion is sensed. Circuit components...

Liu, Yishi

2012-07-16

318

Lifespan-on-a-chip: microfluidic chambers for performing lifelong observation of C. elegans  

E-print Network

device for the liquid culture of many individual nematode worms (Caenorhabditis elegans) in separate. This paper describes the development of a microfluidic device that enables such experi- ments in the nematode

Prentiss, Mara

319

Genome-scale analysis of in vivo spatiotemporal promoter activity in Caenorhabditis elegans  

E-print Network

, in time and in space, is therefore a critical step toward understanding complex biological systems. Here at the genome scale (refs. 10­13, and http://elegans.bcgsc.ca/ perl/eprofile/index). High-magnification

Roth, Frederick

320

Whole-organism integrative expressome for C. elegans enables in silico study of developmental regulation  

E-print Network

The C. elegans nematode has been extensively studied as a model organism since the 1970s, and is the only organism for which the complete cell division tree and the genome are both available. These two datasets were ...

Hutchison, Luke A. D. (Luke Alexander Daysh), 1976-

2011-01-01

321

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

PubMed

Salmonella typhimurium infects both intestinal epithelial cells and macrophages. Autophagy is a lysosomal degradation pathway that is present in all eukaryotes. Autophagy has been reported to limit the Salmonella replication in Caenorhabditis elegans and in mammals. However, it is unknown whether intestinal autophagy activity plays a role in host defense against Salmonella infection in C. elegans. In this study, we inhibited the autophagy gene bec-1 in different C. elegans tissues and examined the survival of these animals following Salmonella infection. Here we show that inhibition of the bec-1 gene in the intestine but not in other tissues confers susceptibility to Salmonella infection, which is consistent with recent studies in mice showing that autophagy is involved in clearance of Salmonella in the intestinal epithelial cells. Therefore, the intestinal autophagy activity is essential for host defense against Salmonella infection from C. elegans to mice, perhaps also in humans. PMID:24674884

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

2014-08-01

322

The regulation of programmed and pathological cell death in C. elegans  

E-print Network

Programmed cell death, or apoptosis, is important in the development and homeostasis of metazoans. In the nematode C. elegans, four genes, egl-1, ced-9, ced-4, and ced-3, constitute the core pathway acting in all somatic ...

Galvin, Brendan D. (Brendan Daniel)

2007-01-01

323

A Decline in p38 MAPK Signaling Underlies Immunosenescence in Caenorhabditis elegans  

E-print Network

The decline in immune function with aging, known as immunosenescence, has been implicated in evolutionarily diverse species, but the underlying molecular mechanisms are not understood. During aging in Caenorhabditis elegans, ...

Youngman, Matthew J.

324

Abl Kinase Inhibits the Engulfment of Apoptotic [corrected] Cells in Caenorhabditis elegans  

E-print Network

The engulfment of apoptotic cells is required for normal metazoan development and tissue remodeling. In Caenorhabditis elegans, two parallel and partially redundant conserved pathways act in cell-corpse engulfment. One ...

Hurwitz, Michael Eliezer

325

SPK-1, an SR protein kinase, inhibits programmed cell death in Caenorhabditis elegans  

E-print Network

To identify genes involved in protecting cells from programmed cell death in Caenorhabditis elegans, we performed a genetic screen to isolate mutations that cause an increase in the number of programmed cell deaths. We ...

Galvin, Brendan D.

326

Receptor-type guanylate cyclase is required for carbon dioxide sensation by Caenorhabditis elegans  

E-print Network

CO2 [CO subscript 2] is both a critical regulator of animal physiology and an important sensory cue for many animals for host detection, food location, and mate finding. The free-living soil nematode Caenorhabditis elegans ...

Hallem, Elissa A.

327

Single molecule fluorescent in situ hybridization (smFISH) of C. elegans worms and embryos  

E-print Network

In C. elegans, the expression pattern of a gene provides important clues to understanding its biological function. To accurately depict endogenous transcriptional activity, a highly sensitive method is required to measure ...

Ji, Ni

328

A Neuronal Acetylcholine Receptor Regulates the Balance of Muscle Excitation and Inhibition in Caenorhabditis elegans  

E-print Network

In the nematode Caenorhabditis elegans, cholinergic motor neurons stimulate muscle contraction as well as activate GABAergic motor neurons that inhibit contraction of the contralateral muscles. Here, we describe the ...

Jospin, Maelle

329

Exoantigen tests for the rapid and specific identification of Apophysomyces elegans and Saksenaea vasiformis.  

PubMed

Apophysomyces elegans and Saksenaea vasiformis frequently fail to sporulate on routine media used in clinical laboratories, thus delaying or preventing their specific identification. We have developed exoantigen test reagents capable of identifying non-sporulating isolates of A. elegans and S. vasiformis. A reagent containing three specific A. elegans precipitins was produced when A. elegans antiserum was absorbed with S. vasiformis. Antigenic analyses showed that at least two serotypes of S. vasiformis exist. Only six of 10 S. vasiformis isolates studied produced bands of identity with S. vasiformis (B-2190) (serotype 1) antiserum absorbed with S. vasiformis (B-2189) (serotype 2) antigens. The remaining four isolates, however, produced bands of identity with S. vasiformis B-2189 antiserum absorbed with B-2190 antigens. Antigenic differences among the isolates of the two groups could be correlated to some extent with the morphologic differences observed, especially with respect to the size of the sporangia and sporangiospores. PMID:2501468

Lombardi, G; Padhye, A A; Standard, P G; Kaufman, L; Ajello, L

1989-01-01

330

Studying host-pathogen interactions and innate immunity in Caenorhabditis elegans  

E-print Network

The genetic analysis of mechanisms of pathogen resistance in the nematode Caenorhabditis elegans has revealed a role for evolutionarily conserved signaling pathways that are required for innate immunity in a wide range of ...

Kim, Dennis H.

331

Biochemical and High Throughput Microscopic Assessment of Fat Mass in Caenorhabditis Elegans  

E-print Network

The nematode C. elegans has emerged as an important model for the study of conserved genetic pathways regulating fat metabolism as it relates to human obesity and its associated pathologies. Several previous methodologies ...

Pino, Elizabeth C.

332

Dopamine Signaling Is Essential for Precise Rates of Locomotion by C. elegans  

E-print Network

Dopamine is an important neuromodulator in both vertebrates and invertebrates. We have found that reduced dopamine signaling can cause a distinct abnormality in the behavior of the nematode C. elegans, which has only eight ...

Omura, Daniel T.

333

Identification of Potential Therapeutic Drugs for Huntington's Disease using Caenorhabditis elegans  

E-print Network

Identification of Potential Therapeutic Drugs for Huntington's Disease using Caenorhabditis elegans, Massachusetts, United States of America Background. The prolonged time course of Huntington's disease (HD, Stockwell BR, et al (2007) Identification of Potential Therapeutic Drugs for Huntington's Disease using

Stockwell, Brent R.

334

Identification of ciliary and ciliopathy genes in Caenorhabditis elegans through comparative genomics  

Microsoft Academic Search

Background  The recent availability of genome sequences of multiple related Caenorhabditis species has made it possible to identify, using comparative genomics, similarly transcribed genes in Caenorhabditis elegans and its sister species. Taking this approach, we have identified numerous novel ciliary genes in C. elegans, some of which may be orthologs of unidentified human ciliopathy genes.\\u000a \\u000a \\u000a \\u000a \\u000a Results  By screening for genes possessing canonical

Nansheng Chen; Allan Mah; Oliver E Blacque; Jeffrey Chu; Kiran Phgora; Mathieu W Bakhoum; C Rebecca Hunt Newbury; Jaswinder Khattra; Susanna Chan; Anne Go; Evgeni Efimenko; Robert Johnsen; Prasad Phirke; Peter Swoboda; Marco Marra; Donald G Moerman; Michel R Leroux; David L Baillie; Lincoln D Stein

2007-01-01

335

A conserved checkpoint monitors meiotic chromosome synapsis inCaenorhabditis elegans  

SciTech Connect

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.

Bhalla, Needhi; Dernburg, Abby F.

2005-07-14

336

A systematic RNAi screen identifies a critical role for mitochondria in C. elegans longevity  

Microsoft Academic Search

We report a systematic RNA interference (RNAi) screen of 5,690 Caenorhabditis elegans genes for gene inactivations that increase lifespan. We found that genes important for mitochondrial function stand out as a principal group of genes affecting C. elegans lifespan. A classical genetic screen identified a mutation in the mitochondrial leucyl-tRNA synthetase gene (lrs-2) that impaired mitochondrial function and was associated

Siu Sylvia Lee; Raymond Y. N. Lee; Andrew G. Fraser; Ravi S. Kamath; Julie Ahringer; Gary Ruvkun

2002-01-01

337

High Local Genetic Diversity and Low Outcrossing Rate in Caenorhabditis elegans Natural Populations  

Microsoft Academic Search

Background: Caenorhabditis elegans is a major model system in biology, yet\\u000avery little is known about its biology outside the laboratory. Especially, its\\u000aunusual mode of reproduction with self-fertile hermaphrodites and facultative\\u000amales raises the question of its frequency of outcrossing in natural\\u000apopulations. Results: We describe the first analysis of C. elegans individuals\\u000asampled directly from natural populations. C.

Antoine Barrière; Marie-Anne Félix

2005-01-01

338

The regulation of feeding and metabolism in response to food deprivation in Caenorhabditis elegans  

Microsoft Academic Search

This review considers the factors involved in the regulation of feeding and metabolism in response to food deprivation using\\u000a Caenorhabditis elegans as a model organism. Some of the sensory neurons and interneurons involved in food intake are described, together with an\\u000a overview of pharyngeal pumping. A number of chemical transmitters control feeding in C. elegans including 5-hydroxytryptamine (5-HT, serotonin), acetylcholine,

Sarah Luedtke; Vincent O’Connor; Lindy Holden-Dye; Robert J. Walker

2010-01-01

339

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

Microsoft Academic Search

Bisphenol A and its halogenated analogues are commonly used industrial chemicals with strong toxicological effects over many\\u000a 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

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

2010-01-01

340

An automated tracking system for Caenorhabditis elegans locomotor behavior and circadian studies application  

Microsoft Academic Search

Automation of simple behavioral patterns, such as locomotor activity, is fundamental for pharmacological and genetic screening studies. Recently, circadian behaviors in locomotor activity and stress responses were reported in the nematode Caenorhabditis elegans, a well-known model in genetics and developmental studies. Here we present a new method for long-term recordings of C. elegans (as well as other similar-sized animals) locomotor

Sergio H. Simonetta; Diego A. Golombek

2007-01-01

341

Profiling Caenorhabditis elegans non-coding RNA expression with a combined microarray  

Microsoft Academic Search

Small non-coding RNAs (ncRNAs) are encoded by genes that function at the RNA level, and several hundred ncRNAs have been identified in various organisms. Here we describe an analysis of the small non-coding transcriptome of Caenorhabditis elegans, microRNAs excepted. As a substantial fraction of the ncRNAs is located in introns of protein-coding genes in C.elegans, we also analysed the relation-

Housheng He; Lun Cai; Geir Skogerbø; Wei Deng; Tao Liu; Xiaopeng Zhu; Yudong Wang; Dong Jia; Zhihua Zhang; Yong Tao; Haipan Zeng; Muhammad Nauman Aftab; Yan Cui; Guozhen Liu; Runsheng Chen

2006-01-01

342

Tyrosinase inhibitory activity of a 6-isoprenoid-substituted flavanone isolated from Dalea elegans  

Microsoft Academic Search

To aid the pharmaceutical and cosmetic industry in the development of alternatives to prevent melanin-related hyperpigmentation disorders, the plant Dalea elegans was submitted to fractionation with the aim of obtaining its anti-tyrosinase principle. Bioguided fractionation of D. elegans led to the isolation of 5,2?,4?-trihydroxy-2?,2?-dimethylchromene-(6,7:5?,6?)-flavanone (1) as the active compound. This novel flavanone, named as dalenin, showed notable activity at inhibiting

María Eugenia Chiari; Domingo Mariano A. Vera; Sara María Palacios; María Cecilia Carpinella

2011-01-01

343

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

PubMed Central

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

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

1991-01-01

344

A Gene for a Low Density Lipoprotein Receptor-Related Protein in the Nematode Caenorhabditis elegans  

Microsoft Academic Search

A >23-kb gene that encodes a large integral membrane protein with a predicted structure similar to that of the low density lipoprotein (LDL) receptor-related protein (LRP) of mammals has been isolated and sequenced from the free-living nematode Caenorhabditis elegans. The 4753-amino acid predicted C. elegans product shares a nearly identical number and arrangement of amino acid sequence motifs with human

John Yochem; Iva Greenwald

1993-01-01

345

The Retrograde IFT Machinery of C. elegans Cilia: Two IFT Dynein Complexes?  

Microsoft Academic Search

We analyzed the relatively poorly understood IFT-dynein (class DYNC2)-driven retrograde IFT pathway in C. elegans cilia, which yielded results that are surprising in the context of current models of IFT. Assays of C. elegans dynein gene expression and intraflagellar transport (IFT) suggest that conventional IFT-dynein contains essential heavy (CHE-3), light-intermediate (XBX-1), plus three light polypeptide chains that participate in IFT,

Limin Hao; Evgeni Efimenko; Peter Swoboda; Jonathan M. Scholey

2011-01-01

346

Invasive cutaneous infection caused by Apophysomyces elegans associated with a spider bite.  

PubMed

Cutaneous infections by Zygomycetes may have underestimated clinical consequences. Apophysomyces elegans is a Zygomycete that rarely causes disease in humans. However, it has been reported with increasing frequency in warm climate zones as a result of infection in healthy patients after injury to the cutaneous barrier. The following case report describes a 30-year-old woman with deep tissue involvement of A. elegans associated with a spider bite and a fatal outcome. PMID:19389070

Saravia-Flores, Marcos; Guaran, Dennya M; Argueta, Victor

2010-05-01

347

Identification of ciliary and ciliopathy genes in Caenorhabditis elegans through comparative genomics  

PubMed Central

Background The recent availability of genome sequences of multiple related Caenorhabditis species has made it possible to identify, using comparative genomics, similarly transcribed genes in Caenorhabditis elegans and its sister species. Taking this approach, we have identified numerous novel ciliary genes in C. elegans, some of which may be orthologs of unidentified human ciliopathy genes. Results By screening for genes possessing canonical X-box sequences in promoters of three Caenorhabditis species, namely C. elegans, C. briggsae and C. remanei, we identified 93 genes (including known X-box regulated genes) that encode putative components of ciliated neurons in C. elegans and are subject to the same regulatory control. For many of these genes, restricted anatomical expression in ciliated cells was confirmed, and control of transcription by the ciliogenic DAF-19 RFX transcription factor was demonstrated by comparative transcriptional profiling of different tissue types and of daf-19(+) and daf-19(-) animals. Finally, we demonstrate that the dye-filling defect of dyf-5(mn400) animals, which is indicative of compromised exposure of cilia to the environment, is caused by a nonsense mutation in the serine/threonine protein kinase gene M04C9.5. Conclusion Our comparative genomics-based predictions may be useful for identifying genes involved in human ciliopathies, including Bardet-Biedl Syndrome (BBS), since the C. elegans orthologs of known human BBS genes contain X-box motifs and are required for normal dye filling in C. elegans ciliated neurons. PMID:17187676

Chen, Nansheng; Mah, Allan; Blacque, Oliver E; Chu, Jeffrey; Phgora, Kiran; Bakhoum, Mathieu W; Hunt Newbury, C Rebecca; Khattra, Jaswinder; Chan, Susanna; Go, Anne; Efimenko, Evgeni; Johnsen, Robert; Phirke, Prasad; Swoboda, Peter; Marra, Marco; Moerman, Donald G; Leroux, Michel R; Baillie, David L; Stein, Lincoln D

2006-01-01

348

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

NASA Astrophysics Data System (ADS)

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.

Wong, Rachel; Brenowitz, Noah; Shen, Amy

2010-11-01

349

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

SciTech Connect

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

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

1988-01-01

350

Caenorhabditis elegans RNA-processing protein TDP-1 regulates protein homeostasis and life span.  

PubMed

Transactive response DNA-binding protein (TARDBP/TDP-43), a heterogeneous nuclear ribonucleoprotein (hnRNP) with diverse activities, is a common denominator in several neurodegenerative disorders, including amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Orthologs of TDP-43 exist in animals ranging from mammals to invertebrates. Here, we systematically studied mutant Caenorhabditis elegans lacking the nematode TDP-43 ortholog, TDP-1. Heterologous expression of human TDP-43 rescued the defects in C. elegans lacking TDP-1, suggesting their functions are conserved. Although the tdp-1 mutants exhibited deficits in fertility, growth, and locomotion, loss of tdp-1 attenuated defects in several C. elegans models of proteotoxicity. Loss of tdp-1 suppressed defects in transgenic C. elegans expressing TDP-43 or CuZn superoxide dismutase, both of which are associated with proteotoxicity in neurodegenerative diseases. Loss of tdp-1 also reduced defects in mutant animals lacking the heat shock factor HSF-1. Transcriptional profiling demonstrated that the loss of TDP-1 altered expression of genes functioning in RNA processing and protein folding. Furthermore, the absence of tdp-1 extended the life span in C. elegans. The life span extension required a FOXO transcriptional factor DAF-16 but not HSF-1. These results suggest that the C. elegans TDP-1 has a role in the regulation of protein homeostasis and aging. PMID:22232551

Zhang, Tao; Hwang, Ho-Yon; Hao, Haiping; Talbot, Conover; Wang, Jiou

2012-03-01

351

Acanthopanax sessiliflorus stem confers increased resistance to environmental stresses and lifespan extension in Caenorhabditis elegans  

PubMed Central

BACKGROUND/OBJECTIVES Acanthopanax sessiliflorus is a native Korean plant and used as traditional medicine or an ingredient in many Korean foods. The free radical theory of aging suggests that cellular oxidative stress caused by free radicals is the main cause of aging. Free radicals can be removed by cellular anti-oxidants. MATERIALS/METHODS Here, we examined the anti-oxidant activity of Acanthopanax sessiliflorus extract both in vitro and in vivo. Survival of nematode C. elegans under stress conditions was also compared between control and Acanthopanax sessiliflorus extract-treated groups. Then, anti-aging effect of Acanthopanax sessiliflorus extract was monitored in C. elegans. RESULTS Stem extract significantly reduced oxidative DNA damage in lymphocyte, which was not observed by leaves or root extract. Survival of C. elegans under oxidative-stress conditions was significantly enhanced by Acanthopanax sessiliflorus stem extract. In addition, Acanthopanax sessiliflorus stem increased resistance to other environmental stresses, including heat shock and ultraviolet irradiation. Treatment with Acanthopanax sessiliflorus stem extract significantly extended both mean and maximum lifespan in C. elegans. However, fertility was not affected by Acanthopanax sessiliflorus stem. CONCLUSION Different parts of Acanthopanax sessiliflorus have different bioactivities and stem extract have strong anti-oxidant activity in both rat lymphocytes and C. elegans, and conferred a longevity phenotype without reduced reproduction in C. elegans, which provides conclusive evidence to support the free radical theory of aging. PMID:25324932

Park, Jin-Kook; Kim, Chul-Kyu; Gong, Sang-Ki; Yu, A-Reum; Lee, Mi-Young

2014-01-01

352

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

PubMed

Resveratrol and SRT1720 have been shown to act as sirtuin activators that may ameliorate type 2 diabetes and metabolic diseases in mice. Moreover, resveratrol extends lifespan in model organisms like C. elegans, N. FURZERI, and possibly D. melanogaster. The aim of the study was to test whether pharmacological concentrations of resveratrol and SRT1720 are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Several hundreds of adult C. ELEGANS roundworms were maintained on agar plates and fed E. COLI strain OP50 bacteria. Resveratrol (5 micromolar, 500 nanomolar) or SRT1720 (1 micromolar, 100 nanomolar) was applied to the agar to test whether they may promote longevity by quantifying survival in the presence and absence of the respective compounds. At a dose of 5 micromolar, which is pharmacologically relevant and 20 times lower than previously published concentrations, resveratrol significantly extends C. elegans lifespan by 3.6% (mean lifespan) and 3.4% (maximum lifespan). By unexpected contrast, SRT1720, which was previously proposed to be several hundred times more active than resveratrol, did not extend lifespan at none of the concentrations tested. Thus, in the model organisms C. elegans, resveratrol is capable of promoting longevity at a concentration that pharmacologically relevant and 20 times lower than previously published doses. The sirtuin activator SRT1720 did not extend lifespan, suggesting that in C. elegans, some relevant effects of resveratrol cannot be mimicked by SRT1720. PMID:20925017

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

2010-11-01

353

?High resolution-magic-angle spinning NMR spectroscopy for metabolic phenotyping of Caenorhabditis elegans.  

PubMed

Analysis of model organisms, such as the submillimeter-size Caenorhabditis elegans, plays a central role in understanding biological functions across species and in characterizing phenotypes associated with genetic mutations. In recent years, metabolic phenotyping studies of C. elegans based on (1)H high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy have relied on the observation of large populations of nematodes, requiring labor-intensive sample preparation that considerably limits high-throughput characterization of C. elegans. In this work, we open new platforms for metabolic phenotyping of C. elegans mutants. We determine rich metabolic profiles (31 metabolites identified) from samples of 12 individuals using a (1)H NMR microprobe featuring high-resolution magic-angle coil spinning (HR-MACS), a simple conversion of a standard HR-MAS probe to ?HR-MAS. In addition, we characterize the metabolic variations between two different strains of C. elegans (wild-type vs slcf-1 mutant). We also acquire a NMR spectrum of a single C. elegans worm at 23.5 T. This study represents the first example of a metabolomic investigation carried out on a small number of submillimeter-size organisms, demonstrating the potential of NMR microtechnologies for metabolomics screening of small model organisms. PMID:24897622

Wong, Alan; Li, Xiaonan; Molin, Laurent; Solari, Florence; Elena-Herrmann, Bénédicte; Sakellariou, Dimitris

2014-06-17

354

A genome-wide view of Caenorhabditis elegans base-substitution mutation processes.  

PubMed

Knowledge of mutation processes is central to understanding virtually all evolutionary phenomena and the underlying nature of genetic disorders and cancers. However, the limitations of standard molecular mutation detection methods have historically precluded a genome-wide understanding of mutation rates and spectra in the nuclear genomes of multicellular organisms. We applied two high-throughput DNA sequencing technologies to identify and characterize hundreds of spontaneously arising base-substitution mutations in 10 Caenorhabditis elegans mutation-accumulation (MA)-line nuclear genomes. C. elegans mutation rate estimates were similar to previous calculations based on smaller numbers of mutations. Mutations were distributed uniformly within and among chromosomes and were not associated with recombination rate variation in the MA lines, suggesting that intragenomic variation in genetic hitchhiking and/or background selection are primarily responsible for the chromosomal distribution patterns of polymorphic nucleotides in C. elegans natural populations. A strong mutational bias from G/C to A/T nucleotides was detected in the MA lines, implicating oxidative DNA damage as a major endogenous mutagenic force in C. elegans. The observed mutational bias also suggests that the C. elegans nuclear genome cannot be at equilibrium because of mutation alone. Transversions dominate the spectrum of spontaneous mutations observed here, whereas transitions dominate patterns of allegedly neutral polymorphism in natural populations of C. elegans and many other animal species; this observation challenges the assumption that natural patterns of molecular variation in noncoding regions of the nuclear genome accurately reflect underlying mutation processes. PMID:19805298

Denver, Dee R; Dolan, Peter C; Wilhelm, Larry J; Sung, Way; Lucas-Lledó, J Ignacio; Howe, Dana K; Lewis, Samantha C; Okamoto, Kazu; Thomas, W Kelley; Lynch, Michael; Baer, Charles F

2009-09-22

355

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

PubMed Central

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

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

2014-01-01

356

Molecular and Genetic Analysis of Adaptive Evolution in the Rare Serpentine Endemic, Caulanthus amplexicaulis var. barbarae (J. Howell) Munz  

E-print Network

amplexicaulis var. amplexicaulis. Using genomic DNA from Caulanthus amplexicaulis var. barbarae, we developed a suite of microsatellite markers. In addition, we developed gene specific markers for genes known in Arabidopsis to be ecologically important. Our...

Burrell, Anna Mildred

2011-10-21

357

Successful treatment of a child with posttraumatic necrotizing fasciitis caused by Apophysomyces elegans: case report and review of literature.  

PubMed

Apophysomyces elegans is an uncommon human pathogen that causes deeply invasive infections in immunocompromised patients and cutaneous infection in immunocompetent patients. We report the development of severe deep soft tissue zygomycosis caused by A. elegans in an otherwise healthy child after trauma. She was successfully treated with surgical debridements and antifungal therapy with liposomal amphotericin B. A review of the literature indicates that zygomycosis caused by A. elegans is associated with traumatic inoculation. PMID:15361732

Kordy, Faisal N; Al-Mohsen, Ibrahim Z; Hashem, Fuad; Almodovar, Edna; Al Hajjar, Sami; Walsh, Thomas J

2004-09-01

358

Antimicrobial activity of Pleurotus eryngii var. ferulae grown on various agro-wastes  

Microsoft Academic Search

In this study, the antimicrobial activity of Pleurotus eryngii var. ferulae grown on various agro- wastes were investigated. The antimicrobial activity from the extract of P. eryngii var. ferulae which was obtained from various culture medium was evaluated according to the disk diffusion method by using Bacillus megaterium DSM 32, Staphylococcus aureus COWAN 1, Escherichia coli ATCC 25922, Klebsiella pneumoniae

Mehmet Akyuz; Sevda Kirbag

359

Polimorfismo en Phaseolus vulgaris var. aborigineus (Fabaceae). Evidencias que indican hibridación natural  

Microsoft Academic Search

A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argentina was studied. In order to know the origin of this polymorphism, some plants belonging to the var. abo- rigineus, other plants showing floral dimorphism and other individuals with particular characters were collect- ed. Their seeds, obtained after field-work treatments of autogamy and free pollination, were sown

Patricia S. Hoc; Shirley M. Espert; Susana I. Drewes; Alicia D. Burghardt

360

A MODIFIED INFORMATION CRITERION FOR COINTEGRATION TESTS BASED ON A VAR APPROXIMATION  

Microsoft Academic Search

We consider the cointegration tests of Johansen (1988, Journal of Economic Dynamics and Control 12, 231 254; 1991, Econometrica 59, 1551 1580) when a vector autoregressive (VAR) process of order k is used to approximate a more general linear process with a possibly infinite VAR representation. Traditional methods to select the lag order, such as Akaike s information criterion (AIC)

Zhongjun Qu; Pierre Perron

2007-01-01

361

Molecular identification of the mycorrhizal fungi of the epiparasitic plant Monotropastrum humile var. glaberrimum (Ericaceae)  

Microsoft Academic Search

Achlorophyllous monotropoid plants (Monotropoideae, Ericaceae) are epiparasites that obtain all of their carbon from their host plants via connections with mycorrhizal fungi. The mycorrhizal fungi of the epiparasitic monotropoid Monotropastrum humile var. glaberrima were identified based on mitochondrial, large ribosomal DNA sequences, and were compared with those of another variety, M. humile var. humile. The fungi that inhabit M. humile

Jun Yokoyama; Tatsuya Fukuda; Hirokazu Tsukaya

2005-01-01

362

Assessing the impact of US ethanol on fossil fuel markets: A structural VAR approach  

Microsoft Academic Search

Despite the growing importance of biofuels, the effect of biofuels on fossil fuel markets is not fully understood. We develop a joint structural Vector Auto Regression (VAR) model of the global crude oil, US gasoline, and US ethanol markets to examine whether the US ethanol market has had any impact on global oil markets. The structural VAR approach provides a

Lihong Lu McPhail

2011-01-01

363

Monetary policy and inflation under the crawling peg: Some evidence from VARs for Colombia  

Microsoft Academic Search

This paper investigates the effects of monetary policy under the crawling peg in Colombia utilizing Granger Causality tests, variance decompositions, and impulse response functions from VARs. Several alternative lag selection criteria are used to specify the lag structures of the VARs. Variations in domestic credit appear to affect the balance of payments but not the exchange rate in Colombia, suggesting

Linda Kamas

1995-01-01

364

Puccinia jaceae var. solstitialis teliospore priming on yellow starthistle.  

PubMed

Following the introduction of Puccinia jaceae var. solstitialis to California for biological control of yellow starthistle (Centaurea solstitialis, Asteraceae), teliospores, pycnia, and multiple urediniospore generations have been observed in the field. Because urediniospores have a relatively short life span in the field, functioning teliospores are expected to be necessary for the permanent establishment of P. jaceae var. solstitialis in California. To determine if conditions in California were conducive to this, teliospore emergence and priming were evaluated in the field. A factorial experiment in the laboratory with five incubation times and three incubation temperatures was used to determine teliospore priming requirements. Teliospore production coincided with plant senescence in August and September at two sites in 2 years; fewer teliospores were produced in 2006, suggesting inconsistent teliospore production may limit population growth and contribute to local extinctions in some areas. When teliospores were primed in the field, germination was low through the fall and abruptly peaked in January during both years. In the laboratory, teliospore germination increased as incubation time increased from 2 to 6 weeks and temperatures decreased from 12 to 4 degrees C. A degree-hour model derived from laboratory data accurately predicts when teliospores are primed for germination in the field. Based on the results obtained in this study, it is apparent that teliospore germination can occur over a range of priming conditions. However, lower temperatures and longer incubation periods are superior in breaking teliospore dormancy. PMID:19055436

Fisher, A J; Aegerter, B J; Gordon, T R; Smith, L; Woods, D M

2009-01-01

365

The effect of storage factors on membrane permeability and sugar content of potatoes and decay by Erwinia carotovora var. atroseptica and Fusarium roseum var. Sambucinum  

Microsoft Academic Search

Russet Burbank and WC230-14 potato tubers were stored at 0 C (32 F) and 5 C (41 F) in air, air plus 4% CO2 and air plus 8% CO2 for a 175 day storage period. Four times during this period, tubers were removed and inoculated withErwinia carotovora var.atroseptica (van Hall) Dye orFusarium roseum var.sambucinum (L. K.) Sn. and H. and

M. Workman; E. Kerschner; M. Harrison

1976-01-01

366

1-MCP is more effective on a floral brassica ( Brassica oleracea var. italica L.) than a leafy brassica ( Brassica rapa var. chinensis)  

Microsoft Academic Search

Florets of broccoli (Brassica oleracea var. italica L.) and the youngest fully expanded leaf detached from pak choy (Brassica rapa var. chinensis) were treated with 1-methylcyclopropene (1-MCP) overnight (16 h) and then stored at supermarket retail temperature (10°C). A concentration of 12 ?l l?1 was considered optimal for both pak choy leaves and broccoli florets. 1-MCP increased shelf life of

Amanda J Able; Lung Sing Wong; Amikha Prasad; Timothy J O'Hare

2002-01-01

367

In vitro biological screening of the stem of Desmodium elegans  

PubMed Central

Objective To explore the medicinal importance of the stem of Desmodium elegans, methanolic extract, and its different solvent fractions were evaluated for brine shrimp lethality, insecticidal and phytotoxicity, antifungal, and antibacterial activities. Methods The methanolic extract and its solvent fractions were tested for cytotoxic, phytotoxic, insecticidal, antifungal, and antibacterial effects using our previous published protocols. Results The methanolic, DCM, ethyl acetate and n-butanol fractions exhibited insecticidal effect against Callosobruchus analis and Rhyzopertha dominic. The methanolic extract, n-hexane, DCM ethyl acetate and n-butanol showed 75, 85, 85, 65 and 5% phytotoxicity at the tested concentration of 500 µg/mL respectively. The solvent fractions (DCM and ethyl acetate) were effective against F. solani (10% and 20% inhibition respectively). All the tested samples were devoid of cytotoxic and antibacterial effects. Conclusion It was concluded that this plant can be practiced for control of weeds and insects. PMID:23998011

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

2013-01-01

368

Experimental determination of invasive fitness in Caenorhabditis elegans.  

PubMed

Estimation of fitness is a key step in experimental evolution studies. However, no established methods currently exist to specifically estimate how successful new alleles are in invading populations. The main reason is that most assays do not accurately reflect the randomness associated with the first stages of the invasion, when invaders are rare and extinctions are frequent. In this protocol, I describe how such experiments can be done in an effective way. By using the nematode model, Caenorhabditis elegans, a large number of invasion experiments are set up, whereby invading individuals carrying a visual marker are introduced into populations in very low numbers. The number of invaders counted in consecutive generations, together with the number of extinctions, is then used in the context of individual-based computer simulations to provide likelihood (Lk) estimates for fitness. This protocol can take up to five generations of experimental invasions and a few hours of computer processing time. PMID:24853925

Chelo, Ivo M

2014-06-01

369

Trimethylpsoralen induces small deletion mutations in Caenorhabditis elegans.  

PubMed Central

To examine the mutagenic spectrum of 4,5',8-trimethylpsoralen (TMP) in Caenorhabditis elegans, we isolated mutations in the unc-22 and pal-1 genes following TMP mutagenesis and analyzed them for restriction fragment length polymorphisms by Southern blot. Eleven of 21 unc-22 mutations exhibited restriction fragment length polymorphisms, 8 of which were deletions of between 0.10 and 15 kb in length. Both of two pal-1 mutations were also small deletions within this size range. Comparison of our results with previous studies on mutagenesis by gamma-rays and x-rays suggests that the mutagenic spectrum of TMP may be similar. TMP should be useful in generating mutations that cause complete loss of function of single genes and that are likely to result in allele-specific DNA polymorphisms. Images PMID:7906415

Yandell, M D; Edgar, L G; Wood, W B

1994-01-01

370

Neurexin and neuroligin mediate retrograde synaptic inhibition in C. elegans.  

PubMed

The synaptic adhesion molecules neurexin and neuroligin alter the development and function of synapses and are linked to autism in humans. Here, we found that Caenorhabditis elegans neurexin (NRX-1) and neuroligin (NLG-1) mediated a retrograde synaptic signal that inhibited neurotransmitter release at neuromuscular junctions. Retrograde signaling was induced in mutants lacking a muscle microRNA (miR-1) and was blocked in mutants lacking NLG-1 or NRX-1. Release was rapid and abbreviated when the retrograde signal was on, whereas release was slow and prolonged when retrograde signaling was blocked. The retrograde signal adjusted release kinetics by inhibiting exocytosis of synaptic vesicles (SVs) that are distal to the site of calcium entry. Inhibition of release was mediated by increased presynaptic levels of tomosyn, an inhibitor of SV fusion. PMID:22859820

Hu, Zhitao; Hom, Sabrina; Kudze, Tambudzai; Tong, Xia-Jing; Choi, Seungwon; Aramuni, Gayane; Zhang, Weiqi; Kaplan, Joshua M

2012-08-24

371

Neurexin and Neuroligin Mediate Retrograde Synaptic Inhibition in C. elegans  

PubMed Central

The synaptic adhesion molecules Neurexin and Neuroligin alter the development and function of synapses and are linked to autism in humans. We find that C. elegans Neurexin (NRX-1) and Neuroligin (NLG-1) mediate a retrograde synaptic signal that inhibits neurotransmitter release at neuromuscular junctions. Retrograde signaling was induced in mutants lacking a muscle microRNA (miR-1) and was blocked in mutants lacking NLG-1 or NRX-1. Release was rapid and abbreviated when the retrograde signal was on whereas release was slow and prolonged when retrograde signaling was blocked. The retrograde signal adjusted release kinetics by inhibiting exocytosis of synaptic vesicles (SVs) that are distal to the site of calcium entry. Inhibition of release was mediated by increased pre-synaptic levels of Tomosyn, an inhibitor of SV fusion. PMID:22859820

Hu, Zhitao; Hom, Sabrina; Kudze, Tambudzai; Tong, Xia-Jing; Choi, Seungwon; Aramuni, Gayane; Zhang, Weiqi; Kaplan, Joshua M.

2013-01-01

372

Axon Regeneration Genes Identified by RNAi Screening in C. elegans  

PubMed Central

Axons of the mammalian CNS lose the ability to regenerate soon after development due to both an inhibitory CNS environment and the loss of cell-intrinsic factors necessary for regeneration. The complex molecular events required for robust regeneration of mature neurons are not fully understood, particularly in vivo. To identify genes affecting axon regeneration in Caenorhabditis elegans, we performed both an RNAi-based screen for defective motor axon regeneration in unc-70/?-spectrin mutants and a candidate gene screen. From these screens, we identified at least 50 conserved genes with growth-promoting or growth-inhibiting functions. Through our analysis of mutants, we shed new light on certain aspects of regeneration, including the role of ?-spectrin and membrane dynamics, the antagonistic activity of MAP kinase signaling pathways, and the role of stress in promoting axon regeneration. Many gene candidates had not previously been associated with axon regeneration and implicate new pathways of interest for therapeutic intervention. PMID:24403161

Nix, Paola; Hammarlund, Marc; Hauth, Linda; Lachnit, Martina; Jorgensen, Erik M.

2014-01-01

373

Methodological considerations for heat shock of the nematode Caenorhabditis elegans.  

PubMed

Stress response pathways share commonalities across many species, including humans, making heat shock experiments valuable tools for many biologists. The study of stress response in Caenorhabditis elegans has provided great insight into many complex pathways and diseases. Nevertheless, the heat shock/heat stress field does not have consensus as to the timing, temperature, or duration of the exposure and protocols differ extensively between laboratories. The lack of cohesiveness makes it difficult to compare results between groups or to know where to start when preparing your own protocol. We present a discussion of some of the major hurdles to reproducibility in heat shock experiments as well as detailed protocols for heat shock and hormesis experiments. PMID:24780523

Zevian, Shannin C; Yanowitz, Judith L

2014-08-01

374

Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

375

Mesoscopic organization reveals the constraints governing C. elegans nervous system  

E-print Network

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. 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). Comparison with other c...

Pan, Raj Kumar; Sinha, Sitabhra

2009-01-01

376

Alternative meiotic chromatid segregation in the holocentric plant Luzula elegans  

PubMed Central

Holocentric chromosomes occur in a number of independent eukaryotic lineages. They form holokinetic kinetochores along the entire poleward chromatid surfaces, and owing to this alternative chromosome structure, species with holocentric chromosomes cannot use the two-step loss of cohesion during meiosis typical for monocentric chromosomes. Here we show that the plant Luzula elegans maintains a holocentric chromosome architecture and behaviour throughout meiosis, and in contrast to monopolar sister centromere orientation, the unfused holokinetic sister centromeres behave as two distinct functional units during meiosis I, resulting in sister chromatid separation. Homologous non-sister chromatids remain terminally linked after metaphase I, by satellite DNA-enriched chromatin threads, until metaphase II. They then separate at anaphase II. Thus, an inverted sequence of meiotic sister chromatid segregation occurs. This alternative meiotic process is most likely one possible adaptation to handle a holocentric chromosome architecture and behaviour during meiosis. PMID:25296379

Heckmann, Stefan; Jankowska, Maja; Schubert, Veit; Kumke, Katrin; Ma, Wei; Houben, Andreas

2014-01-01

377

Primary cutaneous mucormycosis (zygomycosis) caused by Apophysomyces elegans.  

PubMed

A 53 year-old male diabetic presented with a month-old, painful ulcer with necrotic margins over the right thigh. Wound debridement was done twice and the ulcer showed recurrent growth of a white, cottony filamentous structure. Cutaneous mucormycosis was suspected and confirmed by histopathology and a culture isolate of Apophysomyces elegans . The patient was treated with liposomal amphotericin-B and itraconazole followed by partial thickness skin grafting, and then discharged after being prescribed posaconazole syrup for three weeks. Regular follow-up was done and during the last visit after six months following discharge, the ulcer was found to have healed well with no recurrence of the fungus. PMID:18797060

Reddy, I S; Rao, N Raghupathi; Shankar Reddy, V M; Rao, Ratna

2008-01-01

378

Radiation-induced gene expression in the nematode Caenorhabditis elegans  

NASA Technical Reports Server (NTRS)

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.

Nelson, Gregory A.; Jones, Tamako A.; Chesnut, Aaron; Smith, Anna L.

2002-01-01

379

Isolation and culture of larval cells from C. elegans.  

PubMed

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. PMID:21559335

Zhang, Sihui; Banerjee, Diya; Kuhn, Jeffrey R

2011-01-01

380

Malate and Fumarate Extend Lifespan in Caenorhabditis elegans  

PubMed Central

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. PMID:23472183

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

2013-01-01

381

Regulators of AWC-Mediated Olfactory Plasticity in Caenorhabditis elegans  

PubMed Central

While most sensory neurons will adapt to prolonged stimulation by down-regulating their responsiveness to the signal, it is not clear which events initiate long-lasting sensory adaptation. Likewise, we are just beginning to understand how the physiology of the adapted cell is altered. Caenorhabditis elegans is inherently attracted to specific odors that are sensed by the paired AWC olfactory sensory neurons. The attraction diminishes if the animal experiences these odors for a prolonged period of time in the absence of food. The AWC neuron responds acutely to odor-exposure by closing calcium channels. While odortaxis requires a G? subunit protein, cGMP-gated channels, and guanylyl cyclases, adaptation to prolonged odor exposure requires nuclear entry of the cGMP-dependent protein kinase, EGL-4. We asked which candidate members of the olfactory signal transduction pathway promote nuclear entry of EGL-4 and which molecules might induce long-term adaptation downstream of EGL-4 nuclear entry. We found that initiation of long-term adaptation, as assessed by nuclear entry of EGL-4, is dependent on G-protein mediated signaling but is independent of fluxes in calcium levels. We show that long-term adaptation requires polyunsaturated fatty acids (PUFAs) that may act on the transient receptor potential (TRP) channel type V OSM-9 downstream of EGL-4 nuclear entry. We also present evidence that high diacylglycerol (DAG) levels block long-term adaptation without affecting EGL-4 nuclear entry. Our analysis provides a model for the process of long-term adaptation that occurs within the AWC neuron of C. elegans: G-protein signaling initiates long-lasting olfactory adaptation by promoting the nuclear entry of EGL-4, and once EGL-4 has entered the nucleus, processes such as PUFA activation of the TRP channel OSM-9 may dampen the output of the AWC neuron. PMID:20011101

O'Halloran, Damien M.; L'Etoile, Noelle D.

2009-01-01

382

Benzophenones from Hypericum elegans with antioxidant and acetylcholinesterase inhibitory potential  

PubMed Central

Background: Hypericum elegans is used in Bulgarian folk medicine for treatment of wounds, depression, gastrointestinal and bacterial diseases. Objective: Recently, new natural benzophenones: Elegaphenone and O-glycosides: Hypericophenonoside, Neoannulatophenonoside and Elegaphenonoside as well as already known 7-Epiclusianone were isolated from the titled species. The aim of the present study was to evaluate the antioxidant and acetyl cholinesterase inhibitory potential of the isolated compounds. Materials and Methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) di-ammonium salt (ABTS) free radicals, ferric reducing antioxidant power (FRAP) assay as well as inhibition of lipid peroxidation in linoleic acid system were used for determination of antioxidant activity. Modified Ellman's colorimetric method was carried out to assess the acetyl cholinesterase inhibition potential. Hyperoside and Galantamine hydrobromide were used as positive controls. Results: Hypericophenonoside was found to possess the strongest DPPH radical scavenging activity (IC50 = 181.85 ± 6.82 ?M), while Neoannulatophenonoside showed the highest ABTS (IC50 = 0.25 ± 0.005 ?M) and lipid peroxidation inhibitor activity. FRAP activity was demonstrated only by prenylated aglycones – Elegaphenone [942.16 ± 4.03 ?M Trolox Equivalent (TE)] and 7-Epiclusianone (642.95 ± 3.95 ?M TE) and was stronger compared to the control Hyperoside (421.75 ± 9.29 ?M TE). Elegaphenone and 7-Epiclusianone were found to possess moderate acetyl cholinesterase inhibitory potential with IC50 values of 192.19 ± 3.54 ?M and 142.97 ± 4.62 ?M, respectively. Conclusion: The results obtained revealed that H. elegans is a potential natural source of bioactive compounds and benzophenones could be useful in therapy of free radical pathologies and neurodegenerative disorders. PMID:24143038

Zheleva-Dimitrova, Dimitrina; Nedialkov, Paraskev; Momekov, Georgi

2013-01-01

383

Controlling interneuron activity in Caenorhabditis elegans to evoke chemotactic behavior  

PubMed Central

Animals locate and track chemoattractive gradients in the environment to find food. With its small nervous system, Caenorhabditis elegans is a good model system1,2 in which to understand how the dynamics of neural activity control this search behavior. Extensive work on the nematode has identified the neurons that are necessary for the different locomotory behaviors underlying chemotaxis through laser ablation3–7, activity recording in immobilized animals and the study of mutants4,5. However, we do not know the neural activity patterns in C. elegans that are sufficient to control its complex chemotactic behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, we used optogenetics and new optical tools to directly manipulate neural activity in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Surprisingly, we discovered that controlling the dynamics of activity in just one interneuron pair (AIY) was sufficient to force the animal to locate, turn towards and track virtual light gradients. Two distinct activity patterns triggered in AIY as the animal moved through the gradient, controlled reversals and gradual turns to drive chemotactic behavior. Since AIY are post-synaptic to most chemosensory and thermosensory neurons8, these activity patterns in AIY are likely to play an important role in controlling and coordinating different taxis behaviors of the animal. PMID:23000898

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

2012-01-01

384

Transgenerational epigenetics in the germline cycle of Caenorhabditis elegans  

PubMed Central

Epigenetic mechanisms create variably stable changes in gene expression through the establishment of heritable states of chromatin architecture. While many epigenetic phenomena are, by definition, heritably passed through cell division during animal and plant development, evidence suggests that ‘epigenetic states’ may also be inherited across multiple generations. Work in the nematode Caenorhabditis elegans has uncovered a number of mechanisms that participate in regulating the transgenerational passage of epigenetic states. These mechanisms include some that establish and maintain heritable epigenetic information in the form of histone modifications, as well as those that filter the epigenetic information that is stably transmitted. The information appears to influence and help guide or regulate gene activity and repression in subsequent generations. Genome surveillance mechanisms guided by small RNAs appear to be involved in identifying and directing heritable repression of genomic elements, and thus may participate in filtering information that is inappropriate for stable transmission. This review will attempt to summarize recent findings that illustrate this simple nematode to be a truly elegant resource for defining emerging biological paradigms. As the cell lineage that links generations, the germline is the carrier of both genetic and epigenetic information. Like genetic information, information in the epigenome can heritably affect gene regulation and phenotype; yet unlike genetic information, the epigenome of the germ lineage is highly modified within each generation. Despite such alterations, some epigenetic information is highly stable across generations, leading to transgenerationally stable phenotypes that are unlinked to genetic changes. Studies in the nematode C. elegans have uncovered mechanisms that contribute to transgenerational repression as well as to the expression of genes that rely on histone modifying machinery and/or non-coding RNA-based mechanisms. These studies indicate that epigenetic mechanisms operating within the germ cell cycle of this organism filter and maintain an epigenetic memory that is required for germ cell function and can also influence gene expression in somatic lineages. PMID:24678826

2014-01-01

385

Genetic and Molecular Characterization of Programmed Cell Death in the C.elegans Tail-Spike Cell.  

E-print Network

??Work in Caenorhabditis elegans has been instrumental in deciphering the molecular basis of programmed cell death. However, despite extensive characterization of broadacting cell death genes,… (more)

Waase-Maurer, Carine

2007-01-01

386

Chromatin and transcriptional regulators act in a cascade to establish a bilateral asymmetry of the C. elegans nervous system  

E-print Network

Neuroanatomical bilateral asymmetry is a widespread feature in both vertebrates and invertebrates. Although mostly bilaterally symmetric, the nervous system of Caenorhabditis elegans displays bilateral asymmetry. Bilateral ...

Nakano, Shunji, Ph. D. Massachusetts Institute of Technology

2011-01-01

387

Phytologia (February 2013) 95(1)94 Taxonomy of Douglas fir (Pseudotsuga menziesii) infraspecific taxa: vars. menziesii, glauca and  

E-print Network

taxa: vars. menziesii, glauca and oaxacana: nrDNA, cpDNA sequences and leaf essential oils Robert P (Debreczy and Racz, 1995). The leaf essential oils of P. menziesii have been exhaustively studied by von differences in oil composition between coastal (var. menziesii) and inland (var. glauca) varieties. A second

Adams, Robert P.

388

Phytologia (August 2013) 95(3) 215 Juniperus communis var. kelleyi, a new variety from North America  

E-print Network

Phytologia (August 2013) 95(3) 215 Juniperus communis var. kelleyi, a new variety from North_Adams@baylor.edu ABSTRACT Recent molecular analysis of Juniperus communis, world-wide (Adams and Schwarzbach, 2012), has: Juniperus communis var. kelleyi R. P. Adams var. nov. in honor of a former student, Walter A. Kelley. Leaf

Adams, Robert P.

389

Chromosomal location of genes for novel glutenin subunits and gliadins in wild emmer wheat ( Triticum turgidum L. var. dicoccoides )  

Microsoft Academic Search

The glutenin and gliadin proteins of wild emmer wheat, Triticum turgidum L. var. dicoccoides, have potential for improvement of durum wheat ( T. turgidum L. var. durum) quality. The objective of this study was to determine the chromosomes controlling the high molecular weight (HMW) glutenin subunits and gliadin proteins present in three T. turgidum var . dicoccoides accessions (Israel-A, PI-481521,

S. S. Xu; K. Khan; D. L. Klindworth; J. D. Faris; G. Nygard

2004-01-01

390

RNAi screening of human glycogene orthologs in the nematode Caenorhabditis elegans and the construction of the C. elegans glycogene database.  

PubMed

In this study, we selected 181 nematode glycogenes that are orthologous to human glycogenes and examined their RNAi phenotypes. The results are deposited in the Caenorhabditis elegans Glycogene Database (CGGDB) at AIST, Tsukuba, Japan. The most prominent RNAi phenotypes observed are disruptions of cell cycle progression in germline mitosis/meiosis and in early embryonic cell mitosis. Along with the previously reported roles of chondroitin proteoglycans, glycosphingolipids and GPI-anchored proteins in cell cycle progression, we show for the first time that the inhibition of the functions of N-glycan synthesis genes (cytoplasmic alg genes) resulted in abnormal germline formation, ER stress and small body size phenotypes. The results provide additional information on the roles of glycoconjugates in the cell cycle progression mechanisms of germline and embryonic cells. PMID:25091817

Akiyoshi, Sayaka; Nomura, Kazuko H; Dejima, Katsufumi; Murata, Daisuke; Matsuda, Ayako; Kanaki, Nanako; Takaki, Tetsuro; Mihara, Hiroyuki; Nagaishi, Takayuki; Furukawa, Shuhei; Ando, Keiko-Gengyo; Yoshina, Sawako; Mitani, Shohei; Togayachi, Akira; Suzuki, Yoshinori; Shikanai, Toshihide; Narimatsu, Hisashi; Nomura, Kazuya

2015-01-01

391

Tissue-Specific Activities of SARM-ASK1-MKK3 Signaling Coordinate Immunity and Behavior to Pathogenic and Nutritional Bacteria in C. elegans  

E-print Network

Microbes represent both an essential source of nutrition and a potential source of lethal infection to the nematode Caenorhabditis elegans. Immunity in C. elegans requires a signaling module comprised of orthologs of the ...

Kim, Dennis H.

392

Burkholderia pseudomallei kills Caenorhabditis elegans through virulence mechanisms distinct from intestinal lumen colonization  

PubMed Central

The nematode Caenorhabditis elegans is hypersusceptible to Burkholderia pseudomallei infection. However, the virulence mechanisms underlying rapid lethality of C. elegans upon B. pseudomallei infection remain poorly defined. To probe the host-pathogen interaction, we constructed GFP-tagged B. pseudomallei and followed bacterial accumulation within the C. elegans intestinal lumen. Contrary to slow-killing by most bacterial pathogens, B. pseudomallei caused fairly limited intestinal lumen colonization throughout the period of observation. Using grinder-defective mutant worms that allow the entry of intact bacteria also did not result in full intestinal lumen colonization. In addition, we observed a significant decline in C. elegans defecation and pharyngeal pumping rates upon B. pseudomallei infection. The decline in defecation rates ruled out the contribution of defecation to the limited B. pseudomallei colonization. We also demonstrated that the limited intestinal lumen colonization was not attributed to slowed host feeding as bacterial loads did not change significantly when feeding was stimulated by exogenous serotonin. Both these observations confirm that B. pseudomallei is a poor colonizer of the C. elegans intestine. To explore the possibility of toxin-mediated killing, we examined the transcription of the C. elegans ABC transporter gene, pgp-5, upon B. pseudomallei infection of the ppgp-5::gfp reporter strain. Expression of pgp-5 was highly induced, notably in the pharynx and intestine, compared with Escherichia coli-fed worms, suggesting that the host actively thwarted the pathogenic assaults during infection. Collectively, our findings propose that B. pseudomallei specifically and continuously secretes toxins to overcome C. elegans immune responses. PMID:23076282

Ooi, Soon-Keat; Lim, Tian-Yeh; Lee, Song-Hua; Nathan, Sheila

2012-01-01

393

Phenolic glucosides from Dendrobium aurantiacum var. denneanum and their bioactivities.  

PubMed

A new 8,4'-oxyneolignane glucoside 1 has been isolated from the stems of Dendrobium aurantiacum var. denneanum together with six known phenolic glucosides 2?7. The structure of the new compound, including its absolute configuration, was determined by spectroscopic and chemical methods as (?)-(7S,8R,7'E)-4-hydroxy-3,3',5,5'-tetramethoxy-8,4'-oxyneolign-7'-ene-7,9,9'-triol 7,9'-bis-O-?-D-glucopyranoside (1). In the in vitro assays, compound 1 and (?)-syringaresinol-4,4'-bis-O-?-D-glucopyranoside (2) showed evident activity against glutamate-induced neurotoxicity in PC12 cells. Shashenoside I (4) showed a selective cytotoxic activity with the IC?? value of 4.17 ?M against the acute myeloid leukemia cell line MV4-11, while it was inactive against 10 other human tumor cell lines. PMID:23702921

Xiong, Liang; Cao, Zhi-Xing; Peng, Cheng; Li, Xiao-Hong; Xie, Xiao-Fang; Zhang, Ting-Mo; Zhou, Qin-Mei; Yang, Lian; Guo, Li

2013-01-01

394

New saponins from the seeds of Agrostemma githago var. githago.  

PubMed

Two new saponins were isolated from the seeds of Agrostemma githago L. var. githago. On the basis of chemical and spectral evidence their structures were determined to be 3-O-beta-D-xylopyranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta- D- glucuronopyranosylgypsogenin-28-O-beta-D-xylopyranosyl-(1-->4)- [beta-D-glucopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-beta- D-4-O-acetylfucopyranoside and 3-O-beta-D-xylopyranosyl-(1-->3)- [beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-gyp sogenin- 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)- [beta-D-glucopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-beta-D- 4-O-acetylfucopyranoside. PMID:9525108

Siepmann, C; Bader, G; Hiller, K; Wray, V; Domke, T; Nimtz, M

1998-03-01

395

Anti-adipogenic effects of extracts of Ficus deltoidea var. deltoidea and var. angustifolia on 3T3-L1 adipocytes*  

PubMed Central

Objective: This study examined the anti-adipogenic effects of extracts of Ficus deltoidea var. deltoidia and var. angustifolia, a natural slimming aid, on 3T3-L1 adipocytes. Methods: Methanol and water extracts of leaves of the F. deltoidea varieties were analyzed to determine their total flavonoid content (TFC) and total phenolic content (TPC), respectively. The study was initiated by determining the maximum non-toxic dose (MNTD) of the methanol and water extracts for 3T3-L1 preadipocytes. Possible anti-adipogenic effects were then examined by treating 2-d post confluent 3T3-L1 preadipocytes with either methanol extract or water extract at MNTD and half MNTD (½MNTD), after which the preadipocytces were induced to form mature adipocytes. Visualisation and quantification of lipid content in mature adipocytes were carried out through oil red O staining and measurement of optical density (OD) at 520 nm, respectively. Results: The TFCs of the methanol extracts were 1.36 and 1.97 g quercetin equivalents (QE)/100 g dry weight (DW), while the TPCs of the water extracts were 5.61 and 2.73 g gallic acid equivalents (GAE)/100 g DW for var. deltoidea and var. angustilofia, respectively. The MNTDs determined for methanol and water extracts were (300.0±28.3) and (225.0±21.2) ?g/ml, respectively, for var. deltoidea, while much lower MNTDs [(60.0±2.0) ?g/ml for methanol extracts and (8.0±1.0) ?g/ml for water extracts] were recorded for var. angustifolia. Studies revealed that the methanol extracts of both varieties and the water extracts of var. angustifolia at either MNTD or ½MNTD significantly inhibited the maturation of preadipocytes. Conclusions: The inhibition of the formation of mature adipocytes indicated that leaf extracts of F. deltoidea could have potential anti-obesity effects. PMID:24599694

Woon, Shiau Mei; Seng, Yew Wei; Ling, Anna Pick Kiong; Chye, Soi Moi; Koh, Rhun Yian

2014-01-01

396

Vellai et al., 2006 Sex bias in learning in C. elegans Effects of sex and insulin/IGF-1 signaling on performance in  

E-print Network

. elegans Key words: Caenorhabditis elegans, learning, memory, behavioral plasticity, sex bias, insulin, there is a distinct female bias to learn skills that is still unprecedented in other animal taxa. Here we have Caenorhabditis elegans. Using an assay of chemotactic reactions associated with food deprivation, wild-type male

Gems, David

397

Aberrant meiotic behavior in Agave tequilana Weber var. azul  

PubMed Central

Background Agave tequilana Weber var. azul, is the only one variety permitted by federal law in México to be used for tequila production which is the most popular contemporary alcoholic beverage made from agave and recognized worldwide. Despite the economic, genetic, and ornamental value of the plant, it has not been subjected to detailed cytogenetic research, which could lead to a better understanding of its reproduction for future genetic improvement. The objective of this work was to study the meiotic behavior in pollen mother cells and its implications on the pollen viability in Agave tequilana Weber var. azul. Results The analysis of Pollen Mother Cells in anaphase I (A-I) showed 82.56% of cells with a normal anaphase and, 17.44% with an irregular anaphase. In which 5.28% corresponded to cells with side arm bridges (SAB); 3.68% cells with one bridge and one fragment; 2.58% of irregular anaphase showed cells with one or two lagging chromosomes and 2.95% showed one acentric fragment; cells with two bridges and cells with two bridges and one acentric fragment were observed in frequencies of 1.60% and 1.35% respectively. In anaphase II some cells showed bridges and fragments too. Aberrant A-I cells had many shrunken or empty pollen grains (42.00%) and 58.00 % viable pollen. Conclusion The observed meiotic irregularities suggest that structural chromosome aberrations have occurred, such as heterozygous inversions, sister chromatid exchanges, deletions and duplications which in turn are reflected in a low pollen viability. PMID:12396234

Ruvalcaba-Ruiz, Domingo; Rodriguez-Garay, Benjamin

2002-01-01

398

Chemistry and biological activities of Tanacetum chiliophyllum var. oligocephalum extracts.  

PubMed

Tanacetum chiliophyllum (Fisch. & Mey.) var. oligocephalum (D.C.) Sosn. collected in Turkey was subjected to phytochemical and biological evaluations in this study. Pure compounds were obtained from ethyl acetate extracts of the stems of the plant material. Structures of isolated compounds were determined using spectral methods. Seven known flavones, i.e., 5-hydroxy-3',4',6,7-tetramethoxyflavone, eupatilin (6-hydroxyluteolin-6,3',4'-trimethylether), cirsimaritin (scuttellarin-6,7-dimethylether), cirsilineol, 5-hydroxy-3',4',7-trimethoxy flavone, desmethoxy-centaureidin, and jaceosidin and one known triterpene, taraxasterol acetate, were identified from the ethyl acetate extracts. The first seven compounds, as well as the ethyl acetate and methanol extracts, were also investigated for their insecticidal, antimicrobial, and 1,1-diphenyl-2-picrylhydrazil radical (DPPH)-scavenging activities. The insecticidal contact toxicity of the extracts were evaluated on Sitophilus granarius. The ethyl acetate (81.8%) and methanol (88.4%) extracts of T. chiliophyllum var. oligocephalum showed high toxicity against this pest. Most promising antimicrobial activity was observed for ethyl acetate extracts of the stems against Bacillus cereus. This extract showed the same inhibition concentration (125 microL/mg) with the positive control chloramphenicol. The ethyl acetate (91.9%) and methanol (93%) extracts of the stems showed significant DPPH-scavenging activity compared with the positive controls alpha-tocopherol (94.5%) and butylated hydroxytoluene (92.9%) at 10 mg/mL concentration. Among the isolated compounds, the highest DPPH-scavenging activity was observed for jaceosidin at 1 mg/mL concentration (81.5%). PMID:24645497

Polato?lu, Kaan; Karakoç, Omer Cem; Demirci, Fatih; Gökçe, Ayhan; Gören, Nezhun

2013-01-01

399

Genetic relationships and population structure of the endangered Steamboat buckwheat, Eriogonum ovalifolium var. williamsiae (Polygonaceae).  

PubMed

Eriogonum ovalifolium var. williamsiae (Steamboat buckwheat) is a narrow endemic subshrub, known from a single locality in Washoe County, Nevada. We examined genetic structure of the only known population by analyzing patterns of allozyme variation. Our results suggest that Steamboat buckwheat has high genetic variability, with levels of variation similar to that typical of a widespread species rather than a narrow endemic. Genotype frequencies suggest that mating is random. We detected no genetic subdivision of the population. Several clones spanning up to 67 cm were found, but we do not know if such clones are common. We used allozyme data to assess the genetic similarity of var. williamsiae to five other varieties of E. ovalifolium. All six varieties are very similar allozymically with var. williamsiae being the most similar to the widespread var. ovalifolium. Although var. williamsiae and var. ovalifolium are morphologically distinct, their genetic similarity warrants further study to determine whether or not they should be treated as separate taxa. Evidence of male sterility in var. williamsiae plus other data leads us to hypothesize that this taxon might be either a hybrid or undergoing cytoplasmic introgression. Information gathered from this study, in concert with ongoing work on the breeding system of Steamboat buckwheat, should be helpful in forming management strategies for this plant. PMID:11302845

Archibald, J K; Wolf, P G; Tepedino, V J; Bair, J

2001-04-01

400

Phosphorylation of SU(VAR)3-9 by the Chromosomal Kinase JIL-1  

PubMed Central

The histone methyltransferase SU(VAR)3–9 plays an important role in the formation of heterochromatin within the eukaryotic nucleus. Several studies have shown that the formation of condensed chromatin is highly regulated during development, suggesting that SU(VAR)3–9's activity is regulated as well. However, no mechanism by which this may be achieved has been reported so far. As we and others had shown previously that the N-terminus of SU(VAR)3–9 plays an important role for its activity, we purified interaction partners from Drosophila embryo nuclear extract using as bait a GST fusion protein containing the SU(VAR)3–9 N-terminus. Among several other proteins known to bind Su(VAR)3–9 we isolated the chromosomal kinase JIL-1 as a strong interactor. We show that SU(VAR)3–9 is a substrate for JIL-1 in vitro as well as in vivo and map the site of phosphorylation. These findings may provide a molecular explanation for the observed genetic interaction between SU(VAR)3–9 and JIL-1. PMID:20386606

Boeke, Joern; Regnard, Catherine; Cai, Weili; Johansen, J?rgen; Johansen, Kristen M.; Becker, Peter B.; Imhof, Axel

2010-01-01

401

Updates of the HbVar database of human hemoglobin variants and thalassemia mutations  

PubMed Central

HbVar (http://globin.bx.psu.edu/hbvar) is one of the oldest and most appreciated locus-specific databases launched in 2001 by a multi-center academic effort to provide timely information on the genomic alterations leading to hemoglobin variants and all types of thalassemia and hemoglobinopathies. Database records include extensive phenotypic descriptions, biochemical and hematological effects, associated pathology and ethnic occurrence, accompanied by mutation frequencies and references. Here, we report updates to >600 HbVar entries, inclusion of population-specific data for 28 populations and 27 ethnic groups for ?-, and ?-thalassemias and additional querying options in the HbVar query page. HbVar content was also inter-connected with two other established genetic databases, namely FINDbase (http://www.findbase.org) and Leiden Open-Access Variation database (http://www.lovd.nl), which allows comparative data querying and analysis. HbVar data content has contributed to the realization of two collaborative projects to identify genomic variants that lie on different globin paralogs. Most importantly, HbVar data content has contributed to demonstrate the microattribution concept in practice. These updates significantly enriched the database content and querying potential, enhanced the database profile and data quality and broadened the inter-relation of HbVar with other databases, which should increase the already high impact of this resource to the globin and genetic database community. PMID:24137000

Giardine, Belinda; Borg, Joseph; Viennas, Emmanouil; Pavlidis, Cristiana; Moradkhani, Kamran; Joly, Philippe; Bartsakoulia, Marina; Riemer, Cathy; Miller, Webb; Tzimas, Giannis; Wajcman, Henri; Hardison, Ross C.; Patrinos, George P.

2014-01-01

402

Study about locomotory ability of dystrophin-defected C.elegans after spaceflight  

NASA Astrophysics Data System (ADS)

Space microgravity could induce a variety of biological changes such as muscular atrophy. Recent studies show that gravisensing is a key point in muscular atrophy process, but the molecular mechanism is still unknown. Dystrophin, a muscle-related protein, plays an important role in muscle development. It is reported that mutation of human dystrophin gene could cause muscular atrophy. In this study, we focus on whether dystrophin gene acts as a gravisensing factor and observe locomotory ability of dystrophin-defected Caenorhabditis elegans (C.elegans) after spaceflight. We used wild-type (WT) and dystrophin-defected (dys-1) mutant of C.elegans, which were cultured to dauer stage and sent to space by Shenzhou 8 spacecraft (from Nov 1st to 17th, 2011). These worms were divided into three groups: space group (space radiation and microgravity conditions), space control group (space radiation and chmetcnvTCSC0NumberType1NegativeFalseHasSpaceFalseSourceValue1UnitNameg1g centrifuge force conditions) and ground control group.We already observed the progeny (generation F1 and F2) of worms which were sent to space, the movement of C. elegans is restricted to a two-dimensional sinusoidal pattern, and evaluated locomotory ability by the ratio (length/width) in crawl trace wave of C. elegans. The increased value of ratio indicates the decrease in locomotory ability of C. elegans. Our results from generation F1 showed that WT worms in space group(7.7±1.8) demonstrated the significant decrease in locomotory ability about 15%, compared with those in space control group(6.7±1.2). This finding indicates that locomotory ability of C. elegans progeny could be affected by microgravity in space environment. In comparison to the obvious difference in ratio between space group and space control group for WT worms, there is no significant difference between two space groups of generation F2 .For dys-1 mutant of C.elegans (generation F1 and F2), the results show that dystrophin deficiency results in no response to microgravity, compared with WT, suggesting that dys-1 gene plays a role in locomotory ability under ground gravity. Further, we performed all genome microarray analysis and found that expression of several muscle-related genes in dys-1 mutant groups were also changed, accompanied with changes in biological processes such as oxidation, protein modification and metabolic process. Our findings suggest that dystrophin gene could act as a gravisensing and affect locomotory ability of C. elegans progeny.

Gao, Ying; Sun, Yeqing; Lei, Huang; Xu, Dan

2012-07-01

403

Assessment of selenium toxicity on the life cycle of Caenorhabditis elegans.  

PubMed

Selenium (Se) is a growing problem of global concern. Se can cause adverse effects on reproductive systems, which have been linked to declines in animal populations. The soil nematode Caenorhabditis elegans (C. elegans) is a ubiquitous soil organism that is increasingly utilized as a model organism in aquatic and soil toxicology. In the present study, the experimental data for individual body length, survival rate, brood size, and hatching rate were used to evaluate the possible effects of selenite [Se(IV)] on C. elegans. A stage-classified matrix model was applied to the experimental data to provide information on the population dynamics of C. elegans and to assess the Se(IV)-affected asymptotic population growth rate. Estimates of the survival probability showed significant decreases in survival at all stages when C. elegans was exposed to Se(IV). The growth probability of C. elegans in the L1 stage showed the most significant decline, from 0.11 h(-1) (for the control) to 0.04 h(-1) [for exposure to 3 mM Se(IV)]. These results showed that Se(IV) has a profound impact on C. elegans population dynamics. The asymptotic population growth rate (?) was found to range from 1.00 to 0.64 h(-1) for increasing Se(IV) concentrations, implying a potential risk of population decrease for C. elegans exposure to a Se(IV)-contaminated environment. Our study shows how a mechanistic view based on the Se(IV) effects on the soil nematode C. elegans can promote a life cycle toxicity assessment. An important implication of this analysis is that mathematical models can be used to produce a population stage structure, to give clarity to the analysis of the key population-level endpoint (the asymptotic population growth rate) of population dynamics, and to evaluate the influences for the response of other species to environmental Se. These models sequentially provide candidate environmental criteria for the evaluation of the population impact of Se. PMID:24906985

Li, Wen-Hsuan; Ju, Yun-Ru; Liao, Chung-Min; Liao, Vivian Hsiu-Chuan

2014-09-01

404

C. elegans HLH-2/E/Daughterless controls key regulatory cells during gonadogenesis Michael A. Chesney a  

E-print Network

cells in both hermaphrodites and males. The hermaphrodite distal tip cell (hDTC) also provides "leader organ, the Caenor- habditis elegans gonad. The C. elegans hermaphrodite and male gonads derive from two include two "distal tip cells" (DTCs) in each sex, an "anchor cell" (AC) in hermaphrodites and a "linker

Kimble, Judith

405

The Caenorhabditis elegans F-box protein SEL-10 promotes female development and may target FEM-1  

E-print Network

The Caenorhabditis elegans F-box protein SEL-10 and its human homolog have been proposed to regulate LIN-12 Notch cause masculinization of the hermaphrodite soma. Our results demon- strate that mutations causing loss for normal hermaphrodite development. Caenorhabditis elegans develops either as a self-fertilizing XX

Horvitz, H. Robert

406

Copyright 2003 by the Genetics Society of America DIM-1, a Novel Immunoglobulin Superfamily Protein in Caenorhabditis elegans,  

E-print Network

initial muscle assembly in C. elegans to form dense bodies and M-lines. Loss of this protein results in viable animals that have disorganized bodywall muscle and are paralyzed as adults. Loss or reduction Protein in Caenorhabditis elegans, Is Necessary for Maintaining Bodywall Muscle Integrity Teresa M

Moerman, Donald G.

407

nAture methods | vol.6 No.12 | december2009 | 891 the nematode Caenorhabditis elegans has a compact nervous  

E-print Network

Articles nAture methods | vol.6 No.12 | december2009 | 891 the nematode Caenorhabditis elegans has of the fundamental challenges in neuroscience. The nematode Caenorhabditis elegans, with just 302 neurons, roughly 7 neurons in nematodes14­16. Despite these remarkable developments, understanding the neuronal connections

Cai, Long

408

A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans{{  

E-print Network

in the nematode C. elegans{{ Shawn R. Lockery,*a S. Elizabeth Hulme,b William M. Roberts,a Kristin J. Robinson readouts of neuromuscular function in the nematode worm, C. elegans. The device consists of an array to a tree-like arrangement of distribution channels that automatically delivers one nematode to each

Weitz, David

409

Copyright 1999 by the Genetics Society of America Mutational Analysis of the Caenorhabditis elegans Cell-Death Gene ced-3  

E-print Network

proteins termed caspases, prevent programmed cell death in the nematode Caenorhabditis elegans. We used programmed cell death in the nematode Caenorhabditis elegans (Ellis and Horvitz 1986; Yuan (Thornberry et al). These proteases have been named caspases, for cysteine aspases, because they sult in cell death in culture (Miura

Shaham, Shai

410

TRANSCRIPTIONAL REGULATION OF AQP-8, A CAENORHABDITIS ELEGANS AQUAPORIN EXCLUSIVELY EXPRESSED IN THE EXCRETORY SYSTEM, BY THE POU  

E-print Network

homeostasis in the soil-dwelling nematode Caenorhabditis elegans is critical. AQP-8 is a C. elegans aquaporin is perfectly conserved in four nematode species. The octamer site's function was further confirmed by deletion for neuronal cell culturing (2). Consistent with the excretory cell's role in osmoregulation, previous

Baillie, David

411

Adaptive divergence within and between ecotypes of the terrestrial garter snake, Thamnophis elegans , assessed with F ST - Q ST comparisons  

Microsoft Academic Search

Populations of the terrestrial garter snake (Thamnophis elegans) around Eagle Lake in California exhibit dramatic ecotypic differentiation in life history, colouration and morphology across distances as small as a few kilometres. We assayed the role of selection in ecotypic differentiation in T. elegans using FST- QST analysis and identified selective agents using direct and indirect observa- tions. We extended the

M. K. MANIER; C. M. SEYLER; S. J. ARNOLD

2007-01-01

412

Fluoxetine protects against amyloid-beta toxicity, in part via daf-16 mediated cell signaling pathway, in Caenorhabditis elegans  

Microsoft Academic Search

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and is the most common form of dementia in elderly people. The accumulation of amyloid ? (A?) is one of the histopathological hallmarks of AD. A? is aggregated to form oligomers which are toxic to neurons and are critical to the onset and progression of AD. In a Caenorhabditis elegans (C. elegans)

Roongpetch Keowkase; Marwa Aboukhatwa; Yuan Luo

2010-01-01

413

Tracking the Academic and Commercial Outcomes of Public Domain Biology: C. elegans knock outs as a case study  

E-print Network

bodies, and society debate the benefits of moving scientific knowledge into the public domain as a means with human therapeutic or scientific application is often done in animal models. Of the common model organisms, C. elegans is among least expensive and easiest to use for research in development. C. elegan

Moerman, Donald G.

414

The C. elegans Zonula Occludens Ortholog ZOO-1 Cooperates with the Cadherin-Catenin Complex to Recruit Actin during  

E-print Network

The C. elegans Zonula Occludens Ortholog ZOO-1 Cooperates with the Cadherin-Catenin Complex embryo, we have characterized the sole C. elegans ZO family member, ZOO-1. ZOO-1 localizes proteins HMR- 1/E-cadherin and VAB-9/claudin, but surprisingly, not HMP-1/-catenin or HMP-2/-catenin. zoo-1

Zaidel-Bar, Ronen

415

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

PubMed Central

New strategies for expression, purification, functional characterization, and structural determination of membrane-spanning G-protein-coupled receptors (GPCRs) are constantly being developed because of their importance to human health. Here, we report a Caenorhabditis elegans heterologous expression system able to produce milligram amounts of functional native and engineered GPCRs. Both bovine opsin [(b)opsin] and human adenosine A2A subtype receptor [(h)A2AR] expressed in neurons or muscles of C. elegans were localized to cell membranes. Worms expressing these GPCRs manifested changes in motor behavior in response to light and ligands, respectively. With a newly devised protocol, 0.6–1 mg of purified homogenous 9-cis-retinal-bound bovine isorhodopsin [(b)isoRho] and ligand-bound (h)A2AR were obtained from C. elegans from one 10-L fermentation at low cost. Purified recombinant (b)isoRho exhibited its signature absorbance spectrum and activated its cognate G-protein transducin in vitro at a rate similar to native rhodopsin (Rho) obtained from bovine retina. Generally high expression levels of 11 native and mutant GPCRs demonstrated the potential of this C. elegans system to produce milligram quantities of high-quality GPCRs and possibly other membrane proteins suitable for detailed characterization.—Salom, D., Cao, P., Sun, W., Kramp, K., Jastrzebska, B., Jin, H., Feng, Z., Palczewski, K. Heterologous expression of functional G-protein-coupled receptors in Caenorhabditis elegans. PMID:22090314

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

2012-01-01

416

Culture of embryonic C. elegans cells for electrophysiological and pharmacological analyses.  

PubMed

Despite the considerable advantages that C. elegans offers for studying gene function in vivo, this system is quite challenging for in vivo electrophysiological analysis of channel function, particularly in neurons. A major problem is that C. elegans neurons are confined in a pressurized and hard-to-penetrate cuticle. Recently, a method for culturing C. elegans embryonic cells has been developed and numerous researchers have already applied this option to study a variety of native ion channels and transporters using various configurations of the patch-clamp technique. C. elegans embryonic cells are obtained from eggs harvested from synchronized gravid adults and then are dissociated using a combination of enzymatic treatment and manual pipetting. Once plated on a surface covered with peanut lectin, cells adhere and differentiate into neurons, muscle and epithelial cells. Cultured embryonic cells recapitulate the expression of differentiation markers and are found in the culture in proportion to their cell type in the mature embryo. Differentiated cells survive well for at least 2 weeks. It should be noted that postembryonic cells do not appear to be generated in these cultures. Cultures can be used for electrophysiological study, testing of pharmacological sensitivities, and for RNAi. C. elegans cell culture thus constitutes the basis for the application of experimental procedures that are not easily applicable to the intact nematode. PMID:18050435

Bianchi, Laura; Driscoll, Monica

2006-01-01

417

A Heritable Antiviral RNAi Response Limits Orsay Virus Infection in Caenorhabditis elegans N2  

PubMed Central

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. PMID:24587016

Sterken, Mark G.; Snoek, L. Basten; Bosman, Kobus J.; Daamen, Jikke; Riksen, Joost A. G.; Bakker, Jaap; Pijlman, Gorben P.; Kammenga, Jan E.

2014-01-01

418

Utility of Caenorhabditis elegans for assessing heavy metal contamination in artificial soil.  

PubMed

There is an increasing need for the development of soil bioassay protocols. Currently the only internationally standardized soil test organism is the lumbricid earthworm Eisenia fetida. Many alternate soil test organisms have been proposed. This work compares Caenorhabditis elegans to several other test organisms, including E. fetida, for heavy metals in soil. In this evaluation, such factors as ease of testing and culturing, duration of testing, soil volume needed, and the sensitivity of the organism were considered. Results show that C. elegans is more sensitive than most other organisms evaluated and is similar in response to E. fetida. The second issue compares C. elegans LC(50) values to heavy metals criteria specified in the US EPA regulations for land application of sewage sludge. Currently, the regulations are set on total metals in the soil and do not consider bioavailability of the metals. Regulations do not consider soil physiochemical properties, such as organic matter content, clay content, and cation exchange capacity, which have been shown to affect the availability of metals to soil organisms. While the C. elegans LC(50) values are above standard values in artificial soil, work in our lab indicates that the LC(50)s are below regulation values for other soil types. Due to the ease of culturing and testing, good sensitivity, along with the wealth of biological information and ecological relevance, C. elegans is a good organism for use in soil bioassays. PMID:10790509

Peredney, C L; Williams, P L

2000-07-01

419

Deletion of Thioredoxin Reductase and Effects of Selenite and Selenate Toxicity in Caenorhabditis elegans  

PubMed Central

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 1/4th 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. PMID:23936512

Boehler, Christopher J.; Raines, Anna M.; Sunde, Roger A.

2013-01-01

420

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

PubMed Central

Heritable variation in behavioural traits generally has a complex genetic basis1, and thus naturally occurring polymorphisms that influence behaviour have been defined in only rare instances2,3. The isolation of wild strains of Caenorhabditis elegans has facilitated the study of natural genetic variation in this species4 and provided insights into its diverse microbial ecology5. C. elegans responds to bacterial infection with conserved innate immune responses6-8 and, while lacking the immunological memory of vertebrate adaptive immunity, exhibits an aversive learning response to pathogenic bacteria9. Here, we report the molecular characterization of naturally occurring coding polymorphisms in a C. elegans gene encoding a conserved HECT domain-containing E3 ubiquitin ligase, HECW-1. We show that two distinct polymorphisms in neighbouring residues of HECW-1 each affect C. elegans behavioural avoidance of a lawn of Pseudomonas aeruginosa. Neuron-specific rescue and ablation experiments, and genetic interaction analysis suggest that HECW-1 functions in a pair of sensory neurons to inhibit P. aeruginosa lawn avoidance behaviour through inhibition of the neuropeptide receptor NPR-110, which we have previously shown promotes P. aeruginosa lawn avoidance behaviour11. Our data establish a molecular basis for natural variation in a C. elegans behaviour that may undergo adaptive changes in response to microbial pathogens. PMID:22089131

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

2011-01-01

421

Rate of soil egestion by larvae of Hylamorpha elegans (Burm.) and Phytoloema hermanni Germ. (Coleoptera: Scarabaeidae).  

PubMed

Larvae of Hylamorpha elegans (Burm.) and Phytoloema herrmanni Germ. feed on roots, although many Scarabaeidae species are able to feed and survive on soil without living roots. In this study we evaluated the potential of H. elegans and P. herrmanni to ingest soil by estimating the rate of soil egestion. In the laboratory, the rate of soil egestion was determined from gut content and gut transit time of 3rd-instar larvae feeding on soil without roots. The soil egestion rate was 14-21 mg g(-1) d(-1) for H. elegans and 11-16 mg g(-1) d(-1) for P. herrmanni. The gut transit time (time of soil passage from mouth to anus) was 2-3 d for both species and the gut content was 41±2 mg g(-1) for H. elegans and 32±2 mg g(-1) for P. herrmanni. The quantitative importance of feeding activity on soil depends upon the population density of larvae in the field, which ranges from 1 to 25 larvae m(-2), but in severe outbreaks can reach 300 larvae m(-2). High population densities could result in soil egestion rates reaching 20 kg d(-1) ha(-1) for P. herrmanni and 30 kg d(-1) ha(-1) for H. elegans. PMID:21120375

Millas, Paz; Carrillo, Roberto

2010-01-01

422

The phytochemical glaucarubinone promotes mitochondrial metabolism, reduces body fat, and extends lifespan of Caenorhabditis elegans.  

PubMed

Naturally occurring compounds that promote energy expenditure and delay aging in model organisms may be of significant interest, since these substances potentially provide pharmaceutical approaches to tackle obesity and promote healthy lifespan in humans. We aimed to test whether pharmaceutical concentrations of glaucarubinone, a cytotoxic and antimalarial quassinoid known from different species of the plant family Simaroubaceae, are capable of affecting metabolism and/or extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Adult C. elegans roundworms, maintained on agar plates, were fed with E. coli strain OP50 bacteria, and glaucarubinone was applied to the agar to test (i) whether it alters respiration rates and mitochondrial activity, (ii) whether it affects body fat content, and (iii) whether it may promote longevity by quantifying survival in the presence and absence of the compound. We have found that glaucarubinone induces oxygen consumption and reduces body fat content of C. elegans. Moreover and consistent with the concept of mitohormesis, glaucarubinone extends C. elegans lifespan when applied at a concentration of 1 or 10 nanomolar. Taken together, glaucarubinone is capable of reducing body fat and promoting longevity in C. elegans, tentatively suggesting that this compound may promote metabolic health and lifespan in mammals and possibly humans. PMID:21264793

Zarse, K; Bossecker, A; Müller-Kuhrt, L; Siems, K; Hernandez, M A; Berendsohn, W G; Birringer, M; Ristow, M

2011-04-01

423

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

PubMed

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 ?-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. PMID:24361878

Moon, Sunjin; Lee, Yong Woo; Kim, Woo Taek; Lee, Weontae

2014-01-10

424

A HIGH-THROUGHPUT METHOD FOR ASSESSING CHEMICAL TOXICITY USING A CAENORHABDITIS ELEGANS REPRODUCTION ASSAY  

PubMed Central

The National Research Council has outlined the need for non-mammalian toxicological models to test the potential health effects of a large number of chemicals while also reducing the use of traditional animal models. The nematode Caenorhabditis elegans is an attractive alternative model because of its well-characterized and evolutionarily-conserved biology, low cost, and ability to be used in high-throughput screening. A high-throughput method is described for quantifying the reproductive capacity of C. elegans exposed to chemicals for 48 h from the last larval stage (L4) to adulthood using a COPAS Biosort. Initially, the effects of exposure conditions that could influence reproduction were defined. Concentrations of DMSO vehicle ? 1% did not affect reproduction. Previous studies indicated that C. elegans may be influenced by exposure to low pH conditions. At pHs greater than 4.5, C. elegans reproduction was not affected, however below this pH there was a significant decrease in the number of offspring. Cadmium chloride was chosen as a model toxicant to verify that automated measurements were comparable to those of traditional observational studies. EC50 values for cadmium for automated measurements (176-192 ?M) were comparable to those previously reported for a 72-h exposure using manual counting (151 ?M). The toxicity of seven test toxicants on C. elegans reproduction was highly correlative with rodent lethality suggesting that this assay may be useful in predicting the potential toxicity of chemicals in other organisms. PMID:20206647

Boyd, Windy A.; McBride, Sandra J.; Rice, Julie R.; Snyder, Daniel W.; Freedman, Jonathan H.

2010-01-01

425

Quantitative Analysis of Cytokinesis In Situ during C. elegans Postembryonic Development  

PubMed Central

The physical separation of a cell into two daughter cells during cytokinesis requires cell-intrinsic shape changes driven by a contractile ring. However, in vivo, cells interact with their environment, which includes other cells. How cytokinesis occurs in tissues is not well understood. Here, we studied cytokinesis in an intact animal during tissue biogenesis. We used high-resolution microscopy and quantitative analysis to study the three rounds of division of the C. elegans vulval precursor cells (VPCs). The VPCs are cut in half longitudinally with each division. Contractile ring breadth, but not the speed of ring closure, scales with cell length. Furrowing speed instead scales with division plane dimensions, and scaling is consistent between the VPCs and C. elegans blastomeres. We compared our VPC cytokinesis kinetics data with measurements from the C. elegans zygote and HeLa and Drosophila S2 cells. Both the speed dynamics and asymmetry of ring closure are qualitatively conserved among cell types. Unlike in the C. elegans zygote but similar to other epithelial cells, Anillin is required for proper ring closure speed but not asymmetry in the VPCs. We present evidence that tissue organization impacts the dynamics of cytokinesis by comparing our results on the VPCs with the cells of the somatic gonad. In sum, this work establishes somatic lineages in post-embryonic C. elegans development as cell biological models for the study of cytokinesis in situ. PMID:25329167

Bourdages, Karine G.; Lacroix, Benjamin; Dorn, Jonas F.; Descovich, Carlos P.; Maddox, Amy S.

2014-01-01

426

Spontaneous Age-Related Neurite Branching in C. elegans  

PubMed Central

The analysis of morphological changes that occur in the nervous system during normal aging could provide insight into cognitive decline and neurodegenerative disease. Previous studies have suggested that the nervous system of C. elegans maintains its structural integrity with age despite the deterioration of surrounding tissues. Unexpectedly, we observed that neurons in aging animals frequently displayed ectopic branches, and that the prevalence of these branches increased with time. Within age-matched populations, the branching of mechnosensory neurons correlated with decreased response to light touch and decreased mobility. The incidence of branching was influenced by two pathways that can affect the rate of aging, the Jun kinase pathway and the insulin/IGF-1 pathway. Loss of Jun kinase signaling, which slightly shortens lifespan, dramatically increased and accelerated the frequency of neurite branching. Conversely, inhibition of the daf-2 insulin/IGF-1-like signaling pathway, which extends lifespan, delayed and suppressed branching, and this delay required DAF-16/FOXO activity. Both JNK-1 and DAF-16 appeared to act within neurons in a cell-autonomous manner to influence branching, and, through their tissue-specific expression, it was possible to disconnect the rate at which branching occurred from the overall rate of aging of the animal. Old age has generally been associated with the decline and deterioration of different tissues, except in the case of tumor cell growth. To our knowledge, this is the first indication that aging can potentiate another form of growth, the growth of neurite branches, in normal animals. PMID:21697377

Tank, Elizabeth M. H.; Rodgers, Kasey E.; Kenyon, Cynthia

2011-01-01

427

Sexual modulation of neural circuits and behavior in Caenorhabditis elegans.  

PubMed

Sex differences in behavior-both sex-specific and shared behaviors-are fundamental to nearly all animal species. One often overlooked mechanism by which these behavioral differences can be generated is through sex-specific modulation of shared circuitry (i.e., circuits present in both sexes). In vertebrates this modulation is likely regulated by hormone-dependent mechanisms as well as by somatic sex itself; invertebrate models have particular promise for understanding the latter of these. Here we review molecular and behavioral evidence of sexual modulation of shared circuitry in the nematode Caenorhabditis elegans. Multiple behaviors in this species, both copulatory and not, are modulated by the genetic sex of shared neurons and circuit. These studies are close to uncovering the molecular mechanisms by which somatic sex modulates neural function in the worm, mechanisms which may be well conserved in more complex organisms. Improving our understanding of the modulation of neural circuit development and function by somatic sex may lend important insight into sex differences in the mammalian nervous system which, in turn, may have important implications for sex biases in disease. PMID:24937129

Fagan, Kelli A; Portman, Douglas S

2014-09-01

428

Synaptic polarity of the interneuron circuit controlling C. elegans locomotion  

PubMed Central

Caenorhabditis elegans is the only animal for which a detailed neural connectivity diagram has been constructed. However, synaptic polarities in this diagram, and thus, circuit functions are largely unknown. Here, we deciphered the likely polarities of seven pre-motor neurons implicated in the control of worm's locomotion, using a combination of experimental and computational tools. We performed single and multiple laser ablations in the locomotor interneuron circuit and recorded times the worms spent in forward and backward locomotion. We constructed a theoretical model of the locomotor circuit and searched its all possible synaptic polarity combinations and sensory input patterns in order to find the best match to the timing data. The optimal solution is when either all or most of the interneurons are inhibitory and forward interneurons receive the strongest input, which suggests that inhibition governs the dynamics of the locomotor interneuron circuit. From the five pre-motor interneurons, only AVB and AVD are equally likely to be excitatory, i.e., they have probably similar number of inhibitory and excitatory connections to distant targets. The method used here has a general character and thus can be also applied to other neural systems consisting of small functional networks. PMID:24106473

Rakowski, Franciszek; Srinivasan, Jagan; Sternberg, Paul W.; Karbowski, Jan

2013-01-01

429

Genes that regulate both development and longevity in Caenorhabditis elegans  

SciTech Connect

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

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

1995-04-01

430

Quantification of Nociceptive Escape Response in C.elegans  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

431

Production of age-synchronous mass cultures of Caenorhabditis elegans.  

PubMed

Methods are described for culturing large populations of age-synchronous Caenorhabditis elegans throughout the adult life span. Contamination of adult populations by progeny was prevented by constructing double-mutant strains that produce progeny at a frequency of less than .005 per adult at the nonpermissive temperature (25.5 degrees C). Of four double-mutant strains that we have characterized, three have wild-type life spans at 25.5 degrees. The other strain contains a mutant allele, age-1(hx542), that results in an increase in life span of 60% over wild type. All four strains produced sufficient numbers of progeny at the permissive temperature (20 degrees C) to generate populations containing 1-5 x 10(6) nematodes within two weeks. Age-synchronous young adult populations were produced using these strains and have been maintained as adults both in liquid culture and on agar medium. Procedures that reduce E. coli contamination by 30-fold in harvested samples of adults are also described. PMID:7516947

Fabian, T J; Johnson, T E

1994-07-01

432

Identification of genes expressed in C. elegans touch receptor neurons.  

PubMed

The extent of gene regulation in cell differentiation is poorly understood. We previously used saturation mutagenesis to identify 18 genes that are needed for the development and function of a single type of sensory neuron--the touch receptor neuron for gentle touch in Caenorhabditis elegans. One of these genes, mec-3, encodes a transcription factor that controls touch receptor differentiation. By culturing and isolating wild-type and mec-3 mutant cells from embryos and applying their amplified RNA to DNA microarrays, here we have identified genes that are known to be expressed in touch receptors, a previously uncloned gene (mec-17) that is needed for maintaining touch receptor differentiation, and more than 50 previously unknown mec-3-dependent genes. These genes are randomly distributed in the genome and under-represented both for genes that are co-expressed in operons and for multiple members of gene families. Using regions 5' of the start codon of the first 20 genes, we have also identified an over-represented heptanucleotide, AATGCAT, that is needed for the expression of touch receptor genes. PMID:12124626

Zhang, Yun; Ma, Charles; Delohery, Thomas; Nasipak, Brian; Foat, Barrett C; Bounoutas, Alexander; Bussemaker, Harmen J; Kim, Stuart K; Chalfie, Martin

2002-07-18

433

Interactions within the ubiquitin pathway of Caenorhabditis elegans.  

PubMed

The ubiquitin system is a well-conserved and pervasive process for post-synthetic modification of proteins. Three key components of the pathway are required for ubiquitination to occur: the E1 ubiquitin activating enzyme, the E2 ubiquitin conjugating enzyme, and the E3 ubiquitin ligase. There are several different E2 ubiquitin conjugating enzymes and an even greater number of E3 ubiquitin ligases. Interactions between these two groups are critical for substrate ubiquitination. This study reports a two-hybrid analysis of interactions within the ubiquitin system of Caenorhabditis elegans. Forty-three RING finger proteins (presumed E3 ubiquitin ligases) and 14 predicted E2 ubiquitin conjugating enzymes were included in the screen. A total of 31 E2-E3 interactions were uncovered. In addition, the UBC-13 conjugating enzyme was observed to interact with two different E2s, UEV-1 and UBC-1. The interaction of UBC-1 and UBC-13 was confirmed with in vitro ubiquitination reactions. Using NHL-1 as the E3 in the assays, ubiquitination was observed when both UBC-1 and UBC-13 were present but not with either alone. These data imply that some E2s require dimerization in order to function. PMID:15530417

Gudgen, Michelle; Chandrasekaran, Anantharaman; Frazier, Tyralynn; Boyd, Lynn

2004-12-10

434

Family of FLP Peptides in Caenorhabditis elegans and Related Nematodes  

PubMed Central

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 have 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 (FaRPs). These genes, the flp genes, have been used as a starting point to identifying flp genes throughout Nematoda. Nematodes have the largest family of FaRPs 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. PMID:25352828

Li, Chris; Kim, Kyuhyung

2014-01-01

435

Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning  

PubMed Central

In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aeruginosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnC) eliminated nematode killing. Second, the 17 avirulent mutants examined all exhibited reduced cyanide synthesis, and the residual production levels correlated with killing efficiency. Third, exposure to exogenous cyanide alone at levels comparable to the level produced by PAO1 killed nematodes with kinetics similar to those observed with bacteria. The killing was not enhanced if hcnC mutant bacteria were present during cyanide exposure. And fourth, a nematode mutant (egl-9) resistant to P. aeruginosa was also resistant to killing by exogenous cyanide in the absence of bacteria. A model for nematode killing based on inhibition of mitochondrial cytochrome oxidase is presented. The action of cyanide helps account for the unusually broad host range of virulence of P. aeruginosa and may contribute to the pathogenesis in opportunistic human infections due to the bacterium. PMID:11591663

Gallagher, Larry A.; Manoil, Colin

2001-01-01

436

Pseudomonas aeruginosa PAO1 kills Caenorhabditis elegans by cyanide poisoning.  

PubMed

In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aeruginosa PAO1 rapidly paralyzes and kills the nematode Caenorhabditis elegans. Our results imply that hydrogen cyanide is the sole or primary toxic factor produced by P. aeruginosa that is responsible for killing of the nematode. Four lines of evidence support this conclusion. First, a transposon insertion mutation in a gene encoding a subunit of hydrogen cyanide synthase (hcnC) eliminated nematode killing. Second, the 17 avirulent mutants examined all exhibited reduced cyanide synthesis, and the residual production levels correlated with killing efficiency. Third, exposure to exogenous cyanide alone at levels comparable to the level produced by PAO1 killed nematodes with kinetics similar to those observed with bacteria. The killing was not enhanced if hcnC mutant bacteria were present during cyanide exposure. And fourth, a nematode mutant (egl-9) resistant to P. aeruginosa was also resistant to killing by exogenous cyanide in the absence of bacteria. A model for nematode killing based on inhibition of mitochondrial cytochrome oxidase is presented. The action of cyanide helps account for the unusually broad host range of virulence of P. aeruginosa and may contribute to the pathogenesis in opportunistic human infections due to the bacterium. PMID:11591663

Gallagher, L A; Manoil, C

2001-11-01

437

Essential roles of snap-29 in C. elegans  

PubMed Central

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

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

2011-01-01

438

Multiple Mechanisms Contribute to Centriole Separation in C. elegans  

PubMed Central

Summary Centrosome function in cell division requires their duplication, once, and only once, per cell cycle. Underlying centrosome duplication are alternating cycles of centriole assembly and separation [1]. Work in vertebrates has implicated the cysteine protease separase in anaphase-coupled centriole separation (or disengagement) and identified this as a key step in licensing another round of assembly [2]. Current models have separase cleaving a physical link between centrioles, potentially cohesin [3, 4], that prevents reinitiation of centriole assembly unless disengaged. Here, we examine separase function in the C. elegans early embryo. We find that depletion impairs separation and consequently duplication of sperm-derived centrioles at the meiosis-mitosis transition. However, subsequent cycles proceed normally. Whereas mitotic centrioles separate in the context of cortical forces acting on a disassembling pericentriolar material, sperm centrioles are not associated with significant pericentriolar material or subject to strong forces. Increasing centrosomal microtubule nucleation restores sperm centriole separation and duplication in separase-depleted embryos, while forced pericentriolar material disassembly drives premature separation in mitosis. These results emphasize the critical role of cytoskeletal forces and the pericentriolar material in centriole separation. Separase contributes to separation where forces are limited, offering a potential explanation for results obtained in different experimental models [5–7]. PMID:23885867

Cabral, Gabriela; Sans, Sabina Sanegre; Cowan, Carrie R.; Dammermann, Alexander

2013-01-01

439

Age-related changes of nuclear architecture in Caenorhabditis elegans.  

PubMed

Mutations in lamins cause premature aging syndromes in humans, including the Hutchinson-Gilford Progeria Syndrome (HGPS) and Atypical Werner Syndrome. It has been shown that HGPS cells in culture undergo age-dependent progressive changes in nuclear architecture. However, it is unknown whether similar changes in nuclear architecture occur during the normal aging process. We have observed that major changes of nuclear architecture accompany Caenorhabditis elegans aging. We found that the nuclear architecture in most nonneuronal cell types undergoes progressive and stochastic age-dependent alterations, such as changes of nuclear shape and loss of peripheral heterochromatin. Furthermore, we show that the rate of these alterations is influenced by the insulin/IGF-1 like signaling pathway and that reducing the level of lamin and lamin-associated LEM domain proteins leads to shortening of lifespan. Our work not only provides evidence for changes of nuclear architecture during the normal aging process of a multicellular organism, but also suggests that HGPS is likely a result of acceleration of the normal aging process. Because the nucleus is vital for many cellular functions, our studies raise the possibility that the nucleus is a prominent focal point for regulating aging. PMID:16269543

Haithcock, Erin; Dayani, Yaron; Neufeld, Ester; Zahand, Adam J; Feinstein, Naomi; Mattout, Anna; Gruenbaum, Yosef; Liu, Jun

2005-11-15

440

Hormonal regulation of the basic peroxidase isoenzyme from Zinnia elegans.  

PubMed

Xylem differentiation in plants is under strict hormonal regulation. Auxins and cytokinins, together with brassinosteroids (BRs), appear to be the main hormones controlling vascular differentiation. In this report, we study the effect of these hormones on the basic peroxidase isoenzyme from Zinnia elegans (ZePrx), an enzyme involved in lignin biosynthesis. Results showed that auxins and cytokinins induce ZePrx, similarly to the way in which they induce seedling secondary growth (in particular, metaxylem differentiation). Likewise, the exogenous application of BR reduces the levels of ZePrx, in a similar way to their capacity to inhibit seedling secondary growth. Consistent with this notion, the exogenous application of BR reverses the auxin/cytokinin-induced ZePrx expression, but has no effect on the auxin/cytokinin-induced secondary growth. This differential hormonal response is supported by the analysis of the ZePrx promoter, which contains (a) cis-elements directly responsive to these hormones and (b) cis-elements targets of the plethora of transcription factors, such as NAC, MYB, AP2, MADS and class III HD Zip, which are up-regulated during the auxin- and cytokinin-induced secondary growth. Taken together, these results suggest that ZePrx is directly and indirectly regulated by the plethora of hormones that control xylem differentiation, supporting the role of ZePrx in xylem lignification. PMID:19626339

Gutiérrez, Jorge; López Núñez-Flores, María Josefa; Gómez-Ros, Laura V; Novo Uzal, Esther; Esteban Carrasco, Alberto; Díaz, José; Sottomayor, Mariana; Cuello, Juan; Ros Barceló, Alfonso

2009-09-01

441

Genotypic-specific variance in Caenorhabditis elegans lifetime fecundity  

PubMed Central

Organisms live in heterogeneous environments, so strategies that maximze fitness in such environments will evolve. Variation in traits is important because it is the raw material on which natural selection acts during evolution. Phenotypic variation is usually thought to be due to genetic variation and/or environmentally induced effects. Therefore, genetically identical individuals in a constant environment should have invariant traits. Clearly, genetically identical individuals do differ phenotypically, usually thought to be due to stochastic processes. It is now becoming clear, especially from studies of unicellular species, that phenotypic variance among genetically identical individuals in a constant environment can be genetically controlled and that therefore, in principle, this can be subject to selection. However, there has been little investigation of these phenomena in multicellular species. Here, we have studied the mean lifetime fecundity (thus a trait likely to be relevant to reproductive success), and variance in lifetime fecundity, in recently-wild isolates of the model nematode Caenorhabditis elegans. We found that these genotypes differed in their variance in lifetime fecundity: some had high variance in fecundity, others very low variance. We find that this variance in lifetime fecundity was negatively related to the mean lifetime fecundity of the lines, and that the variance of the lines was positively correlated between environments. We suggest that the variance in lifetime fecundity may be a bet-hedging strategy used by this species. PMID:25360248

Diaz, S Anaid; Viney, Mark

2014-01-01

442

D-beta-hydroxybutyrate extends lifespan in C. elegans  

PubMed Central

The ketone body beta-hydroxybutyrate (?HB) 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 ?HB supplementation on the lifespan of C. elegans nematodes. ?HB supplementation extended mean lifespan by approximately 20%. RNAi knockdown of HDACs hda-2 or hda-3 also increased lifespan and further prevented ?HB-mediated lifespan extension. ?HB-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. ?HB did not extend lifespan in a genetic model of dietary restriction indicating that ?HB is likely functioning through a similar mechanism. ?HB addition also upregulated ?HB 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 ?HB dehydrogenase activity induced by ?HB addition, suggesting that F55E10.6 functions as an inducible ?HB dehydrogenase. Furthermore, ?HB 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-?HB extends lifespan through inhibiting HDACs and through the activation of conserved stress response pathways. PMID:25127866

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

2014-01-01

443

Pharyngeal pumping continues after laser killing of the pharyngeal nervous system of C. elegans  

SciTech Connect

Using a laser microbeam to kill specific subsets of the pharyngeal nervous system of C. elegans, we found that feeding was accomplished by two separately controlled muscle motions, isthmus peristalsis and pumping. The single neuron M4 was necessary and sufficient for isthmus peristalsis. The MC neurons were necessary for normal stimulation of pumping in response to food, but pumping continued and was functional in MC- worms. The remaining 12 neuron types were also unnecessary for functional pumping. No operation we did, including destruction of the entire pharyngeal nervous system, abolished pumping altogether. When we killed all pharyngeal neurons except M4, the worms were viable and fertile, although retarded and starved. Since feeding is one of the few known essential actions controlled by the nervous system, we suggest that most of the C. elegans nervous system is dispensable in hermaphrodites under laboratory conditions. This may explain the ease with which nervous system mutants are isolated and handled in C. elegans.

Avery, L.; Horvitz, H.R. (Massachusetts Institute of Technology, Cambridge (USA))

1989-10-01

444

Cell culturing of Caenorhabditis elegans glial cells for the assessment of cytosolic Ca²? dynamics.  

PubMed

Cell culture has emerged as an important research method for studying various types of primary cells, including neurons and glial cells. This method has been especially instrumental in assessing intracellular Ca(2+) dynamics of neural cells. The invertebrate model organism Caenorhabditis elegans has been extensively used in neurobiology to study wide-spread issues ranging from gene regulation to behavior. We present some of the basic morphological characteristics of the four C. elegans glial cells residing in the cephalic sensilla of the worm, followed by a description of cell culturing methods for these glial cells. We describe the combined genetic and fluorescence microscopy approaches for identification of C. elegans glial cells in culture and assessment of their cytosolic Ca(2+) dynamics. PMID:22144307

Stout, Randy F; Parpura, Vladimir

2012-01-01

445

Strongyloides stercoralis daf-2 encodes a divergent ortholog of Caenorhabditis elegans DAF-2?  

PubMed Central

We hypothesize that developmental arrest in infectious larvae of parasitic nematodes is regulated by signaling pathways homologous to Caenorhabditis elegans DAF (dauer formation) pathways. Alignment of Strongyloides stercoralis (Ss) DAF-2 with DAF-2 of C. elegans and homologs of other species shows that most structural motifs in these insulin-like receptors are conserved. However, the catalytic domain of Ss-DAF-2 contains two substitutions (Q1242 and Q1256), that would result in constitutive dauer formation in C. elegans or diabetes in vertebrate animals. Ss-daf-2 also shows two alternately spliced isoforms, the constitutively expressed Ss-daf-2a, and Ss-daf-2b, which is only expressed in stages leading to parasitism. PMID:23500073

Massey, Holman C.; Ranjit, Najju; Stoltzfus, Jonathan D.; Lok, James B.

2013-01-01

446

Motility analysis of the nematode C. elegans on wet soft media  

NASA Astrophysics Data System (ADS)

Undulatory locomotion is widely utilized by limbless organisms such as snakes, eels and worms. When moving on top of wet soft gels (e.g. agar), undulating organisms such as the nematode Caenorhabditis elegans display a motility gait that is characterized by crawling. Until present however, a detailed understanding of how C. elegans' crawling gait generates propulsion over soft gels is lacking. Namely, how much crawling force does C. elegans generate? Here, we propose a simple model based on lubrication theory to examine the biomechanics of crawling motion. In analogy to the well-known resistive-force theory (RFT) for low Reynolds number swimming, our model provides a mechanism for the linear relation between the sliding speeds and the drag forces, and sheds light on the role of grooves created by nematodes on agar. We further examine the kinematics of locomotion experimentally and compare muscle activity patterns between crawling and swimming gaits, emphasizing the inherent differences in nematode adaptability to different environments.

Sznitman, Josue; Shen, Xiaoning; Arratia, Paulo

2011-11-01

447

The Intersection of Aging, Longevity Pathways, and Learning and Memory in C. elegans  

PubMed Central

Our understanding of the molecular and genetic regulation of aging and longevity has been greatly augmented through studies using the small model system, C. elegans. It is important to test whether mutations that result in a longer life span also extend the health span of the organism, rather than simply prolonging an aged state. C. elegans can learn and remember both associated and non-associated stimuli, and many of these learning and memory paradigms are subject to regulation by longevity pathways. One of the more distressing results of aging is cognitive decline, and while no gross physical defects in C. elegans sensory neurons have been identified, the organism does lose the ability to perform both simple and complex learned behaviors with age. Here we review what is known about the effects of longevity pathways and the decline of these complex learned behaviors with age, and we highlight outstanding questions in the field. PMID:23226155

Stein, Geneva M.; Murphy, Coleen T.

2012-01-01

448

Most Caenorhabditis elegans microRNAs Are Individually Not Essential for Development or Viability  

PubMed Central

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. PMID:18085825

Lau, Nelson C; Hellman, Andrew B; McGonagle, Shannon M; Bartel, David P; Ambros, Victor R; Horvitz, H. Robert

2007-01-01

449

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

PubMed Central

Metals have been definitively linked to a number of disease states. Due to the widespread existence of metals in our environment from both natural and anthropogenic sources, understanding the mechanisms of their cellular detoxification is of upmost importance. Organisms have evolved cellular detoxification systems including glutathione, metallothioneins, pumps and transporters, and heat shock proteins to regulate intracellular metal levels. The model organism, Caenorhabditis elegans (C. elegans), contains these systems and provides several advantages for deciphering the mechanisms of metal detoxification. This review provides a brief summary of contemporary literature on the various mechanisms involved in the cellular detoxification of metals, specifically, antimony, arsenic, cadmium, copper, manganese, mercury, and depleted uranium using the C. elegans model system for investigation and analysis. PMID:21876692

Martinez-Finley, Ebany J.; Aschner, Michael

2011-01-01

450

Engineering the Caenorhabditis elegans Genome Using Cas9-Triggered Homologous Recombination  

PubMed Central

Study of the nematode Caenorhabditis elegans has provided important insights in a wide range of fields in biology. The ability to precisely modify genomes is critical to fully realize the utility of model organisms. Here, we report a method to edit the C. elegans genome using the Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR) RNA-guided Cas9 nuclease followed by homologous recombination. We demonstrate that Cas9 is able to induce DNA double-strand breaks with specificity for targeted sites, and that these breaks can be efficiently repaired by homologous recombination. By supplying engineered homologous repair templates, we generated GFP knock-ins and targeted mutations. Together, our results outline a flexible methodology to produce essentially any desired modification in the C. elegans genome quickly and at low cost. This technology is an important addition to the array of genetic techniques already available in this experimentally tractable model organism. PMID:23995389

Dickinson, Daniel J.; Ward, Jordan D.; Reiner, David J.; Goldstein, Bob

2013-01-01

451

Effects of Cotton Expressing the 'Bacillus thuringiensis' var. 'kurstaki' Endotoxin on Soil Microorganisms.  

National Technical Information Service (NTIS)

Many agriculturally important plants have been engineered to produce endotoxins from different subspecies of the bacterium Bacillus thuringiensis (B.t.). The endotoxin Bacillus thuringensis var. kurstake (B.t.k.) has demonstrated insecticidal activity aga...

K. K. Donegan, R. J. Seidler

1996-01-01

452

Life History Traits of the Threatened Purple Amole (Chlorogalum Purpureum var. Purpureum): Fort Hunter Liggett, California.  

National Technical Information Service (NTIS)

Researchers monitored the threatened plant, purple amole (Chlorogalum purpureum var. purpureum) at Fort Hunter Liggett, California, from 1998 to 2004. The objectives of this research were to complete a statistical analysis of these data to evaluate: (1) d...

D. Woodbury, E. R. Clark, J. A. Guretzky

2005-01-01

453

of Chlamydia psittaci var ovis: screening in a murine model. Infect Immun 42, 525-530  

E-print Network

of Chlamydia psittaci var ovis: screening in a murine model. Infect Immun 42, 525-530 Rodolakis A- pneumoniae, dès la naissance, en faisant appel à la protection transmise aux porcelets par les anticorps

Paris-Sud XI, Université de

454

Phytoremediation of cadmium-contaminated farmland soil by the hyperaccumulator Beta vulgaris L. var. cicla.  

PubMed

A field study was conducted to evaluate the phytoremediation efficiency of cadmium (Cd) contaminated soil utilizing the Cd hyperaccumulator Beta vulgaris L. var. cicla during one growing season (about 2 months) on farmland in Zhangshi Irrigation Area, the representative wastewater irrigation area in China. Results showed that B. vulgaris L. var. cicla is a promising plant in the phytoremediation of Cd contaminated farmland soil. The maximum of Cd phytoremediation efficiency by B. vulgaris L. var. cicla reached 144.6 mg/ha during one growing season. Planting density had a significant effect on the plant biomass and the overall Cd phytoremediation efficiency (p < 0.05). The amendment of organic manure promoted the biomass increase of B. vulgaris L. var. cicla (p < 0.05) but inhibited the Cd phytoremediation efficiency. PMID:22286610

Song, Xueying; Hu, Xiaojun; Ji, Puhui; Li, Yushuang; Chi, Guangyu; Song, Yufang

2012-04-01

455

Pseudomonas fluorescens NZI7 repels grazing by C. elegans, a natural predator  

PubMed Central

The bacteriovorous nematode Caenorhabditis elegans has been used to investigate many aspects of animal biology, including interactions with pathogenic bacteria. However, studies examining C. elegans interactions with bacteria isolated from environments in which it is found naturally are relatively scarce. C. elegans is frequently associated with cultivation of the edible mushroom Agaricus bisporus, and has been reported to increase the severity of bacterial blotch of mushrooms, a disease caused by bacteria from the Pseudomonas fluorescens complex. We observed that pseudomonads isolated from mushroom farms showed differential resistance to nematode predation. Under nutrient poor conditions, in which most pseudomonads were consumed, the mushroom pathogenic isolate P. fluorescens NZI7 was able to repel C. elegans without causing nematode death. A draft genome sequence of NZI7 showed it to be related to the biocontrol strain P. protegens Pf-5. To identify the genetic basis of nematode repellence in NZI7, we developed a grid-based screen for mutants that lacked the ability to repel C. elegans. The mutants isolated in this screen included strains with insertions in the global regulator GacS and in a previously undescribed GacS-regulated gene cluster, ‘EDB' (‘edible'). Our results suggest that the product of the EDB cluster is a poorly diffusible or cell-associated factor that acts together with other features of NZI7 to provide a novel mechanism to deter nematode grazing. As nematodes interact with NZI7 colonies before being repelled, the EDB factor may enable NZI7 to come into contact with and be disseminated by C. elegans without being subject to intensive predation. PMID:23426012

Burlinson, Peter; Studholme, David; Cambray-Young, Joanna; Heavens, Darren; Rathjen, John; Hodgkin, Jonathan; Preston, Gail M

2013-01-01

456

Caenorhabditis elegans: A Model System for Anti-Cancer Drug Discovery and Therapeutic Target Identification  

PubMed Central

The nematode Caenorhabditis elegans (C. elegans) offers a unique opportunity for biological and basic medical researches due to its genetic tractability and well-defined developmental lineage. It also provides an exceptional model for genetic, molecular, and cellular analysis of human disease-related genes. Recently, C. elegans has been used as an ideal model for the identification and functional analysis of drugs (or small-molecules) in vivo. In this review, we describe conserved oncogenic signaling pathways (Wnt, Notch, and Ras) and their potential roles in the development of cancer stem cells. During C. elegans germline development, these signaling pathways regulate multiple cellular processes such as germline stem cell niche specification, germline stem cell maintenance, and germ cell fate specification. Therefore, the aberrant regulations of these signaling pathways can cause either loss of germline stem cells or overproliferation of a specific cell type, resulting in sterility. This sterility phenotype allows us to identify drugs that can modulate the oncogenic signaling pathways directly or indirectly through a high-throughput screening. Current in vivo or in vitro screening methods are largely focused on the specific core signaling components. However, this phenotype-based screening will identify drugs that possibly target upstream or downstream of core signaling pathways as well as exclude toxic effects. Although phenotype-based drug screening is ideal, the identification of drug targets is a major challenge. We here introduce a new technique, called Drug Affinity Responsive Target Stability (DARTS). This innovative method is able to identify the target of the identified drug. Importantly, signaling pathways and their regulators in C. elegans are highly conserved in most vertebrates, including humans. Therefore, C. elegans will provide a great opportunity to identify therapeutic drugs and their targets, as well as to understand mechanisms underlying the formation of cancer.

Kobet, Robert A.; Pan, Xiaoping; Zhang, Baohong; Pak, Stephen C.; Asch, Adam S.; Lee, Myon-Hee

2014-01-01

457

Influence of silicon on resistance of Zinnia elegans to Myzus persicae (Hemiptera: Aphididae).  

PubMed

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). Z. elegans plants were irrigated every 2 d throughout the duration of the experiment with a nutrient solution amended with potassium silicate (K2SiO2), or a nutrient solution without K2SiO2. Length of the prereproductive period and survivorship of M. persicae were not affected by K2SiO2 treatment, but total cumulative fecundity and the intrinsic rate of increase (r(m)) were slightly reduced on Z. elegans plants receiving soluble silicon. Quantification of silicon content in leaf tissues using inductively coupled plasma optical emission spectroscopy (ICP-OES) confirmed significantly higher silicon concentrations in plants treated with K2SiO2 compared with control plants. High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis was used to identify and quantify phenolic acids and flavonols in leaf tissue of Z. elegans. Compared with untreated control plants, significant elevations in 5-caffeoylquinic acid, p-coumaroylquinic acid, and rutin were detected in leaves of Z. elegans plants treated with K2SiO2, but none of seven other phenolics were significantly affected. Similarly, a slight elevation in guaiacol peroxidase activity was detected in plants treated with K2SiO2 Overall, these results indicate treatment of Z. elegans with soluble silicon provides a modest increase in resistance levels to M. persicae, which may be caused in part by defense-related compounds. PMID:19791606

Ranger, Christopher M; Singh, Ajay P; Frantz, Jonathan M; Cañas, Luis; Locke, James C; Reding, Michael E; Vorsa, Nicholi

2009-02-01

458

Simultaneous transcription of duplicated var2csa gene copies in individual Plasmodium falciparum parasites  

Microsoft Academic Search

ABSTRACT: BACKGROUND: Single nucleotide polymorphisms are common in duplicated genes, causing functional preservation, alteration or silencing. The Plasmodium falciparum genes var2csa and Pf332 are duplicated in the haploid genome of the HB3 parasite line. Whereas the molecular function of Pf332 remains to be elucidated, VAR2CSA is known to be the main adhesin in placental parasite sequestration. Sequence variations introduced upon

Ulf Ribacke; Sandra Nilsson; Johan Ankarklev; Kirsten Moll; Mats Wahlgren; Qijun Chen

2009-01-01

459

Soil bio-functioning under Acacia nilotica var. tomentosa protected forest along the Senegal River  

Microsoft Academic Search

Acacia nilotica var. tomentosa trees from the Diarra protected forest located in the Senegal River valley were identified for the assessment of both biological\\u000a nitrogen fixation, using the natural abundance method, and soil bio-functioning parameters (nodulation, root biomass, total\\u000a microbial biomass, and potential N mineralization). The presence and the genetic diversity of indigenous rhizobia nodulating\\u000a A. nilotica var. tomentosa was also

Aliou Faye; Saidou Sall; Jean-Luc Chotte; Didier Lesueur

2007-01-01

460

Analysis of genetic diversity in Agave tequilana var. Azul using RAPD markers  

Microsoft Academic Search

By federal law in Mexico, A. tequilana Weber var. Azul is the only variety of agave permitted for the production of any tequila. Our objective was to assay levels\\u000a of genetic variation in field populations of A. tequilana var. Azul using randomly amplified polymorphic DNA (RAPD) markers. Ten plants were collected from each of four different\\u000a fields, with two fields

Katia Gil Vega; Mario González Chavira; Octavio Martínez de la Vega; June Simpson; George Vandemark

2001-01-01