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1

Actinomucor elegans var. kuwaitiensis isolated from the wound of a diabetic patient.  

PubMed

The new variety of Actinomucor elegans var. kuwaitiensis, isolated from an open necrotic wound of a diabetic patient is described. This strain differed from the two previously described varieties of A. elegans, A. elegans var. elegans and A. elegans var. meitauzae by nearly 1% or more sequence divergence within D1/D2 regions of 28S rRNA and the ITS region of rRNA genes. Like the other two varieties, no zygospores were observed; however, there was evidence suggesting intersexual diploidy, a feature not described previously in this species. Additionally, A. elegans var. kuwaitiensis was pathogenic to white mice causing 100% mortality within 5 days. PMID:18496764

Khan, Zia U; Ahmad, Suhail; Mokaddas, Eiman; Chandy, Rachel; Cano, Josep; Guarro, Josep

2008-10-01

2

Abutilon theophrasti's defense against the allelochemical benzoxazolin-2(3H)-one: support by Actinomucor elegans.  

PubMed

Abutilon theophrasti Medik., previously found to be rather insensitive to benzoxazinoid containing rye mulch and the allelochemical benzoxazolin-2(3H)-one (BOA), can be associated with the zygomycete Actinomucor elegans, whereby the fungus colonizes the root relatively superficially and mainly in the maturation zone. The fungus mitigates necrosis of the cotyledons when seedlings are incubated with 2 mM BOA, in contrast to those that lack the fungus. In liquid cultures of the fungus, tryptophan was identified. The accumulation of tryptophan is increased in presence of BOA. This amino acid seems to be important in protecting Abutilon against BOA and its derivatives since it suppressed the accumulation of BOA derived, highly toxic 2-aminophen-oxazin-3-one (APO) in the medium and on the root surface during BOA incubations of Abutilon seedlings. Although A. elegans is insensitive to BOA and APO, the fungus is not able to protect the plant against harmful effects of APO, when seedlings are treated with the compound. Abutilon can detoxify BOA via BOA-6-OH glucosylation probably by a cell wall associated glucosyltransferase, but only low amounts of the product accumulate. Low tryptophan concentrations can contribute to a degradation of the toxic intermediate BOA-6-OH by Fenton reactions, whereby the amino acid is oxidized. One of the oxidation products was identified as 4(1H)-quinolinone, which is the core substructure of the quorum sensing molecule 2-heptyl-3-hydroxy-4-quinolone. The mutualistic association of Abutilon theophrasti with Actinomucor elegans is considered as opportunistic and facultative. Such plant-fungus associations depend rather likely on environmental conditions, such as the mode of fertilization. PMID:25432667

Kia, Sevda Haghi; Schulz, Margot; Ayah, Emmanuel; Schouten, Alexander; Müllenborn, Carmen; Paetz, Christian; Schneider, Bernd; Hofmann, Diana; Disko, Ulrich; Tabaglio, Vincenzo; Marocco, Adriano

2014-12-01

3

Production of a new pyridine N-oxide by bioconversion with Cunninghamella echinulata var. elegans.  

PubMed

A new N-oxide was produced from 3-(N-Boc-aminomethyl)-5-bromopyridine by bioconversion with Cunninghamella echinulata var. elegans ATCC 9245, and its structure was established based on the spectral data. The microbial N-oxidation is efficient and highly selective. The substrate was transformed into the product in 7 days. PMID:22762974

Zeng, Jia; Gage, David; Zhan, Jixun

2012-11-01

4

Bioconversion of Stemodia maritima diterpenes and derivatives by Cunninghamella echinulata var. elegans and Phanerochaete chrysosporium.  

PubMed

Stemodane and stemarane diterpenes isolated from the plant Stemodia maritima and their dimethylcarbamate derivatives were fed to growing cultures of the fungi Cunninghamella echinulata var. elegans ATCC 8688a and Phanerochaete chrysosporium ATCC 24725. C. echinulata transformed stemodin (1) to its 7alpha-hydroxy- (2), 7beta-hydroxy- (3) and 3beta-hydroxy- (4) analogues. 2alpha-(N,N-Dimethylcarbamoxy)-13-hydroxystemodane (6) gave 2alpha-(N,N-dimethylcarbamoxy)-6alpha,13-dihydroxystemodane (7) and 2alpha-(N,N-dimethylcarbamoxy)-7alpha,13-dihydroxystemodane (8). Stemodinone (9) yielded 14-hydroxy-(10) and 7beta-hydroxy- (11) congeners along with 1, 2 and 3. Stemarin (13) was converted to the hitherto unreported 6alpha,13-dihydroxystemaran-19-oic acid (18). 19-(N,N-Dimethylcarbamoxy)-13-hydroxystemarane (14) yielded 13-hydroxystemaran-19-oic acid (17) along with the two metabolites: 19-(N,N-dimethylcarbamoxy)-2beta,13-dihydroxystemarane (15) and 19-(N,N-dimethylcarbamoxy)-2beta,8,13-trihydroxystemarane (16). P. chrysosporium converted 1 into 3, 4 and 2alpha,11beta,13-trihydroxystemodane (5). The dimethylcarbamate (6) was not transformed by this microorganism. Stemodinone (9) was hydroxylated at C-19 to give 12. Both stemarin (13) and its dimethylcarbamate (14) were recovered unchanged after incubation with Phanerochaete. PMID:16725164

Lamm, Andrew S; Reynolds, William F; Reese, Paul B

2006-06-01

5

[C. elegans defence mechanisms].  

PubMed

The nematode Caenorhabditis elegans has evolved as a powerful invertebrate model to study innate immunity to pathogens. C. elegans possesses inducible defence mechanisms to protect itself from pathogenic attack, mainly by the production of antimicrobial effector molecules. Its innate immune system is under the control of a surprisingly complex network of evolutionary conserved signalling pathways, which are activated depending on the pathogen, suggesting that C. elegans is able to mount a specific defence response to different pathogens. In this review we will introduce the worm's immune system and discuss the different signalling pathways that regulate its response to bacterial pathogens which mainly infect C. elegans by an oral route and by invading its intestine, before focusing our attention on the resistance of C. elegans to a natural occurring fungal -pathogen that infects the worm by invading its -epidermis. PMID:19480831

Ziegler, Katja; Pujol, Nathalie

2009-05-01

6

C. elegans TRP channels  

PubMed Central

TRP (transient receptor potential) channels represent a superfamily of cation channels found in all eukaryotes. The C. elegans genome encodes seventeen TRP channels covering all of the seven TRP subfamilies. Genetic analyses in C. elegans have implicated TRP channels in a wide spectrum of behavioral and physiological processes, ranging from sensory transduction (e.g. chemosensation, touch sensation, proprioception and osmosensation) to fertilization, drug dependence, organelle biogenesis, apoptosis, gene expression, and neurotransmitter/hormone release. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. Studies in C. elegans have also revealed some previously unrecognized functions and regulatory mechanisms of TRP channels. C. elegans represents an excellent genetic model organism for the study of function and regulation of TRP channels in vivo. PMID:21290304

Xiao, Rui; Xu, X.Z. Shawn

2010-01-01

7

Inocybe hirsuta var. maxima  

NSDL National Science Digital Library

Inocybe hirsuta var. maxima A. H. Smith (SAT 01-279-08) photographed in the Hoh River Valley in Olympic National Park, Washington, USA. This variety is common in Washington under western hemlock and is also known from eastern North America under eastern hemlock.

Steve Trudell

2004-03-09

8

Laser Microsurgery in Caenorhabditis elegans  

PubMed Central

Laser killing of cell nuclei has long been a powerful means of examining the roles of individual cells in C. elegans. Advances in genetics, laser technology, and imaging have further expanded the capabilities and usefulness of laser surgery. Here, we review the implementation and application of currently used methods for target edoptical disruption in C. elegans. PMID:22226524

Fang-Yen, Christopher; Gabel, Christopher V.; Samuel, Aravinthan D. T.; Bargmann, Cornelia I.; Avery, Leon

2013-01-01

9

Antioxidant Activity and Delayed Aging Effects of Hot Water Extract from Chamaecyparis obtusa var. formosana Leaves.  

PubMed

The antioxidant activity and delayed aging effects of hot water extracts from leaves of Chamaecyparis obtusa var. formosana were investigated. Free radical, superoxide radical scavenging, and total phenolic content assays were employed to evaluate the in vitro activities of the extracts. In addition, in vivo assays using the nematode Caenorhabditis elegans were also performed in this study. The results showed that among all soluble fractions obtained from the extracts, the ethyl acetate-soluble fraction has the best in vitro and in vivo antioxidant activities. Moreover, it decreased significantly the deposition of lipofuscin (aging pigment) and extended the lifespan of C. elegans. Bioactivity-guided fractionation yielded six potent antioxidant constituents from the ethyl acetate-soluble fraction, namely, catechin, quercetin, quercetin-3-O-?-rhamnoyranoside, myricetin-3-O-?-rhamnoyranoside, vanillic acid, and 4-hydroxybenzoic acid. Quercetin-3-O-?-rhamnoyranoside pretreatment showed the highest survival of C. elegans upon juglone exposure. Taken together, the results revealed that hot water extracts from C. obtusa var. formosana leaves have the potential to be used as a source for antioxidant or delayed aging health food. PMID:24766147

Cheng, Szu-Chin; Li, Wen-Hsuan; Shi, Yeu-Ching; Yen, Pei-Ling; Lin, Huan-You; Liao, Vivian Hsiu-Chuan; Chang, Shang-Tzen

2014-05-01

10

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

11

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

12

Chemosensory signaling in C. elegans.  

PubMed

The nematode Caenorhabditis elegans can sense and respond to hundreds of different chemicals with a simple nervous system, making it an excellent model for studies of chemosensation. The chemosensory neurons that mediate responses to different chemicals have been identified through laser ablation studies, providing a cellular context for chemosensory signaling. Genetic and molecular analyses indicate that chemosensation in nematodes involves G protein signaling pathways, as it does in vertebrates, but the receptors and G proteins involved belong to nematode-specific gene families. It is likely that about 500 different chemosensory receptors are used to detect the large spectrum of chemicals to which C. elegans responds, and one of these receptors has been matched with its odorant ligand. C. elegans olfactory responses are also subject to regulation based on experience, allowing the nematode to respond to a complex and changing chemical environment. PMID:10580986

Troemel, E R

1999-12-01

13

An Automated Micropositioning System for Investigating C. elegans  

E-print Network

. elegans and other similar microorganisms. (JALA 2009;14:269­76) INTRODUCTION The nematode Caenorhabditis elegans (C. elegans), a soil-dwelling worm having a relatively simple and extremely well characterized

Sun, Yu

14

Proteomic analysis of Caenorhabditis elegans  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

15

Electrophysiological Methods for C. elegans Neurobiology  

PubMed Central

Patch-clamp electrophysiology is the technique of choice for the biophysical analysis of the function of nerve, muscle, and synapse in C. elegans nematodes. Considerable technical progress has been made in C. elegans electrophysiology in the decade since the initial publication of this technique. Today, most, if not all electrophysiological studies that can be done in larger animal preparations can also be done in C. elegans. This chapter has two main goals. The first is to present to a broad audience the many techniques available for patch-clamp analysis of neurons, muscles, and synapses in C. elegans. The second is to provide a methodological introduction to the techniques for patch-clamping C. elegans neurons and body-wall muscles in vivo, including emerging methods for optogenetic stimulation coupled with post-synaptic recording. We also present samples of the cell-intrinsic and post-synaptic ionic currents that can be measured in C. elegans nerve and muscle. PMID:22226532

Goodman, Miriam B.; Lindsay, Theodore H.; Lockery, Shawn R.; Richmond, Janet E.

2014-01-01

16

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

17

Touch sensitivity in Caenorhabditis elegans  

Microsoft Academic Search

The nematode Caenorhabditis elegans was the first organism for which touch insensitive mutants were obtained. The study of the genes defective in these mutants\\u000a has led to the identification of components of a mechanosensory complex needed for specific cells to sense gentle touch to\\u000a the body. Multiple approaches using genetics, cell biology, biochemistry, and electrophysiology have characterized a channel\\u000a complex,

Alexander Bounoutas; Martin Chalfie

2007-01-01

18

Sensory Transduction in Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

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

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

19

Germline Transformation of Caenorhabditis elegans by Injection  

NASA Astrophysics Data System (ADS)

Microinjection is a commonly used technique for DNA transformation in Caenorhabditis elegans. It is a powerful tool that links genetic and molecular analysis to phenotypic analysis. In this chapter we shall provide an overview of microinjection for germline transformation in worms. Our discussion will emphasize C. elegans reproductive biology, applications and protocols for carrying out microinjection in order to successfully obtain transgenic worms.

Kadandale, Pavan; Chatterjee, Indrani; Singson, Andrew

20

Staphylococcal Biofilm Exopolysaccharide Protects against Caenorhabditis elegans  

E-print Network

increasingly difficult to treat due to the prevalence of antibiotic resistance in these organisms. The ability to living and artificial surfaces and to resist host immune factors and antibiotics. Here, we show of the C. elegans intestine. These studies demonstrate that C. elegans can serve as a simple animal model

Ausubel, Frederick M.

21

Regulation of Body Fat in Caenorhabditis elegans.  

PubMed

Over the past decade, studies conducted in Caenorhabditis elegans have helped to uncover the ancient and complex origins of body fat regulation. This review highlights the powerful combination of genetics, pharmacology, and biochemistry used to study energy balance and the regulation of cellular fat metabolism in C. elegans. The complete wiring diagram of the C. elegans nervous system has been exploited to understand how the sensory nervous system regulates body fat and how food perception is coupled with the production of energy via fat metabolism. As a model organism, C. elegans also offers a unique opportunity to discover neuroendocrine factors that mediate direct communication between the nervous system and the metabolic tissues. The coming years are expected to reveal a wealth of information on the neuroendocrine control of body fat in C. elegans. PMID:25340962

Srinivasan, Supriya

2015-02-10

22

Cocaine Modulates Locomotion Behavior in C. elegans  

E-print Network

Cocaine, a potent addictive substance, is an inhibitor of monoamine transporters, including DAT (dopamine transporter), SERT (serotonin transporter) and NET (norepinephrine transporter). Cocaine administration induces complex behavioral alterations in mammals, but the underlying mechanisms are not well understood. Here, we tested the effect of cocaine on C. elegans behavior. We show for the first time that acute cocaine treatment evokes changes in C. elegans locomotor activity. Interestingly, the neurotransmitter serotonin, rather than dopamine, is required for cocaine response in C. elegans.TheC. elegans SERT MOD-5 is essential for the effect of cocaine, consistent with the role of cocaine in targeting monoamine transporters. We further show that the behavioral response to cocaine is primarily mediated by the ionotropic serotonin receptor MOD-1. Thus, cocaine modulates locomotion behavior in C. elegans primarily by impinging on its serotoninergic system.

Alex Ward; Vyvyca J. Walker; Zhaoyang Feng; X. Z. Shawn Xu

2009-01-01

23

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.

24

Prion protein in Caenorhabditis elegans  

PubMed Central

The infectious agent of prion diseases is believed to be nucleic acid-free particles composed of misfolded conformational isomers of a host protein known as prion protein (PrP). Although this “protein-only” concept is generally accepted, decades of extensive research have not been able to elucidate the mechanisms by which PrP misfolding leads to neurodegeneration and infectivity. The challenges in studying prion diseases relate in part to the limitations of mammalian prion models, which include the long incubation period post-infection until symptoms develop, the high expense of maintaining mammals for extended periods, as well as safety issues. In order to develop prion models incorporating a genetically tractable simple system with a well-defined neuronal system, we generated transgenic C. elegans expressing the mouse PrP behind the pan-neuronal ric-19 promoter (Pric-19). We show here that high expression of Pric-19::PrP in C. elegans can result in altered morphology, defective mobility and shortened lifespan. Low expression of Pric-19::PrP, however, does not cause any detectable harm. Using the dopamine neuron specific promoter Pdat-1, we also show that expression of the murine BAX, a pro-apoptotic member of the Bcl-2 family, causes dopamine neuron destruction in the nematode. However, co-expression of PrP inhibits BAX-mediated dopamine neuron degeneration, demonstrating for the first time that PrP has anti-BAX activity in living animals. Thus, these distinct PrP-transgenic C. elegans lines recapitulate a number of functional and neuropathological features of mammalian prion models and provide an opportunity for facile identification of genetic and environmental contributors to prion-associated pathology. PMID:21084837

Park, Kyung-Won

2011-01-01

25

Using Caenorhabditis elegans to Study Serpinopathies  

PubMed Central

Protein misfolding, polymerization, and/or aggregation are hallmarks of serpinopathies and many other human genetic disorders including Alzheimer’s, Huntington’s, and Parkinson’s disease. While higher organism models have helped shape our understanding of these diseases, simpler model systems, like Caenorhabditis elegans, offer great versatility for elucidating complex genetic mechanisms underlying these diseases. Moreover, recent advances in automated high-throughput methodologies have promoted C. elegans as a useful tool for drug discovery. In this chapter, we describe how one could model serpinopathies in C. elegans and how one could exploit this model to identify small molecule compounds that can be developed into effective therapeutic drugs. PMID:21683258

Long, Olivia S.; Gosai, Sager J.; Kwak, Joon Hyeok; King, Dale E.; Perlmutter, David H.; Silverman, Gary A.; Pak, Stephen C.

2015-01-01

26

4D-Var Developement at GMAO  

NASA Technical Reports Server (NTRS)

The Global Modeling and Assimilation Offce (GMAO) is currently using an IAU-based 3D-Var data assimilation system. GMAO has been experimenting with a 3D-Var-hybrid version of its data assimilation system (DAS) for over a year now, which will soon become operational and it will rapidly progress toward a 4D-EnVar. Concurrently, the machinery to exercise traditional 4DVar is in place and it is desirable to have a comparison of the traditional 4D approach with the other available options, and evaluate their performance in the Goddard Earth Observing System (GEOS) DAS. This work will also explore the possibility for constructing a reduced order model (ROM) to make traditional 4D-Var computationally attractive for increasing model resolutions. Part of the research on ROM will be to search for a suitably acceptable space to carry on the corresponding reduction. This poster illustrates how the IAU-based 4D-Var assimilation compares with our currently used IAU-based 3D-Var.

Pelc, Joanna S.; Todling, Ricardo; Akkraoui, Amal El

2014-01-01

27

Gait synchronization in Caenorhabditis elegans  

PubMed Central

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.

2014-01-01

28

C. elegans outside the Petri dish.  

PubMed

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

Frézal, Lise; Félix, Marie-Anne

2015-01-01

29

C. elegans outside the Petri dish  

PubMed Central

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

Frézal, Lise; Félix, Marie-Anne

2015-01-01

30

Phospholipase C? regulates ovulation in Caenorhabditis elegans  

Microsoft Academic Search

Phospholipase C? (PLC?) is a novel class of phosphoinositide-specific PLC with unknown physiological functions. Here, we present the first genetic analysis of PLC? in an intact organism, the nematode Caenorhabditis elegans. Ovulation in C. elegans is dependent on an inositol 1,4,5-trisphosphate (IP3) signaling pathway activated by the receptor tyrosine kinase LET-23. We generated deletion mutants of the gene, plc-1, encoding

Ken-ichi Kariya; Yen Kim Bui; Xianlong Gao; Paul W. Sternberg; Tohru Kataoka

2004-01-01

31

Forward and reverse mutagenesis in C. elegans  

PubMed Central

Mutagenesis drives natural selection. In the lab, mutations allow gene function to be deciphered. C. elegans is highly amendable to functional genetics because of its short generation time, ease of use, and wealth of available gene-alteration techniques. Here we provide an overview of historical and contemporary methods for mutagenesis in C. elegans, and discuss principles and strategies for forward (genome-wide mutagenesis) and reverse (target-selected and gene-specific mutagenesis) genetic studies in this animal. PMID:24449699

Kutscher, Lena M.; Shaham, Shai

2014-01-01

32

Cancer models in C. elegans  

PubMed Central

Although now dogma, the idea that non-vertebrate organisms such as yeast, worms, and flies could inform, and in some cases even revolutionize, our understanding of oncogenesis in humans was not immediately obvious. Aided by the conservative nature of evolution and the persistence of a cohort of devoted researchers, the role of model organisms as a key tool in solving the cancer problem has, however, become widely accepted. In this review, we focus on the nematode Caenorhabditis elegans and its diverse and sometimes surprising contributions to our understanding of the tumorigenic process. Specifically, we discuss findings in the worm that address a well-defined set of processes known to be deregulated in cancer cells including cell cycle progression, growth factor signaling, terminal differentiation, apoptosis, the maintenance of genome stability, and developmental mechanisms relevant to invasion and metastasis. PMID:20175192

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

2013-01-01

33

Large-scale transgenesis and nerve regeneration in C. elegans  

E-print Network

Caenorhabditis elegans (C. elegans) is a widely studied model organism due to their fully mapped neural network of 302 neurons and amenable genetics. Their small size and short life cycle allows for rapid studies to be ...

Gilleland, Cody Lee

2014-01-01

34

Volatiles of Chrysanthemum zawadskii var. latilobum K  

PubMed Central

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

2012-01-01

35

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

E-print Network

capacity.2 C. elegans possesses three major mechanisms of defences against microbial attacks:1 immune response of the C. elegans epidermis. INTRODUCTION C. elegans is a freeliving soil nematode function are more susceptible to infection.11,12,3 The third line of defence involves inducible mechanisms

Ewbank, Jonathan

36

Microsporidia Are Natural Intracellular Parasites of the Nematode Caenorhabditis elegans  

Microsoft Academic Search

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

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

2008-01-01

37

Chemically defined medium and Caenorhabditis elegans  

PubMed Central

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. PMID:14580264

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

2003-01-01

38

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

39

EHV and UHV Line Loadbility Dependence on Var Supply Vapability  

Microsoft Academic Search

Optimization algorithms for power system operation and planning employ EHV and UHV line loadability limits as well as var supply limits. Traditional line loadability limits are based on stability limits which assume infinite var supply capability. This paper shows the critical dependence of line loadability on var supplies and presents a method to compute line loadability limits that are consistent

T. W. Kay; P. W. Sauer; R. D. Shultz; R. A. Smith

1982-01-01

40

Static VAr compensator with neural network control  

Microsoft Academic Search

Artificial neural networks (ANNs) have been used in many applications of pattern classification, speech synthesis and recognition, function approximation, associative memory and control. Because of their adaptive nature and parallel computational features, they are promising a lot of hope for future of engineering. In this study, an application of ANN in control has been presented. A static VAr compensator model

B. Mumyakmaz; Xianhe Jin; Changchang Wang; T. C. Cheng

1999-01-01

41

Volt\\/VAr control at distribution substations  

Microsoft Academic Search

This paper proposes new methods to improve the performance of the current volt\\/VAr control schemes at distribution substations. The approach makes use of the new measurement and computer resources that are now available at the substations. The paper shows that new supervisory type control schemes can be developed to improve the performance of both the voltage regulator controllers and also

Mesut E. Baran; Ming-Yung Hsu

1999-01-01

42

Lipid constituents of Trifolium resupinatum var. microcephalum  

Microsoft Academic Search

The two new compounds (3-methyl-1-nonene-3-ol and 2?,3?-dihydroxy propyl pentadecanoate) and four known compounds were isolated from Trifolium resupinatum L. var. microcephalum Zoh. (Leguminosae). All the compounds were reported for the first time from this plant. The stuructures of the isolates were determined by 1D, 2D NMR techniques and MS spectroscopy.

Temine Sabudak; Emel Isik; Sevil Oksuz

2007-01-01

43

Lipid constituents of Trifolium resupinatum var. microcephalum.  

PubMed

The two new compounds (3-methyl-1-nonene-3-ol and 2',3'-dihydroxy propyl pentadecanoate) and four known compounds were isolated from Trifolium resupinatum L. var. microcephalum Zoh. (Leguminosae). All the compounds were reported for the first time from this plant. The stuructures of the isolates were determined by 1D, 2D NMR techniques and MS spectroscopy. PMID:17654289

Sabudak, Temine; Isik, Emel; Oksuz, Sevil

2007-07-20

44

Host-Microbe Interactions in Caenorhabditis elegans  

PubMed Central

A good understanding of how microbes interact with hosts has a direct bearing on our capability of fighting infectious microbial pathogens and making good use of beneficial ones. Among the model organisms used to study reciprocal actions among microbes and hosts, C. elegans may be the most advantageous in the context of its unique attributes such as the short life cycle, easiness of laboratory maintenance, and the availability of different genetic mutants. This review summarizes the recent advances in understanding host-microbe interactions in C. elegans. Although these investigations have greatly enhanced our understanding of C. elegans-microbe relationships, all but one of them involve only one or few microbial species. We argue here that more research is needed for exploring the evolution and establishment of a complex microbial community in the worm's intestine and its interaction with the host. PMID:23984180

Hou, Aixin

2013-01-01

45

Biotransformation of fluorobiphenyl by Cunninghamella elegans.  

PubMed

The fungus Cunninghamella elegans is a useful model of human catabolism of xenobiotics. In this paper, the biotransformation of fluorinated biphenyls by C. elegans was investigated by analysis of the culture supernatants with a variety of analytical techniques. 4-Fluorobiphenyl was principally transformed to 4-fluoro-4'-hydroxybiphenyl, but other mono- and dihydroxylated compounds were detected in organic extracts by gas chromatography-mass spectrometry. Additionally, fluorinated water-soluble products were detected by (19)F NMR and were identified as sulphate and beta-glucuronide conjugates. Other fluorobiphenyls (2-fluoro-, 4,4'-difluoro- and 2,3,4,5,6-pentafluoro-biphenyl) were catabolised by C. elegans, yielding mono- and dihydroxylated products, but phase II metabolites were detected from 4,4'-difluorobiphenyl only. PMID:19956946

Amadio, Jessica; Murphy, Cormac D

2010-03-01

46

C. elegans survivors without telomerase  

PubMed Central

In most eukaryotic organisms with a linear genome, the telomerase complex is essential for telomere maintenance and, thus, for genomic integrity. Proper telomerase function in stem and germ cell populations counteracts replication-dependent telomere shortening. On the other hand, repression of telomerase expression in most somatic tissues limits the proliferative potential of these cells through the induction of a permanent cell cycle arrest termed senescence upon critical telomere erosion. Thus, senescence, induced by telomere shortening and subsequent DNA damage signaling, is an essential tumor suppressive mechanism, emphasized by the fact that repression of telomerase is lost in about 90% of cancers, endowing them with unlimited proliferative potential. In 10% of cancers telomeres are maintained using the recombination-based alternative mechanism of telomere lengthening (ALT). To date, ALT and ALT-like mechanisms have only been described in the context of individual cells such as cancer cells and yeast. Now, several “survivor” strains of the nematode Caenorhabditis elegans have been generated that can propagate despite mutations of the telomerase gene. These nematode strains represent the first multi-cellular organism with canonical telomerase that can survive in the absence of a functional telomerase pathway. PMID:24058854

Lackner, Daniel H.; Karlseder, Jan

2013-01-01

47

Eph receptor signaling in C. elegans  

PubMed Central

Eph receptor protein-tyrosine kinases are among the oldest known animal receptors and have greatly expanded in number during vertebrate evolution. Their complex transduction mechanisms are capable of bidirectional and bimodal (multi-response) signaling. Eph receptors are expressed in almost every cell type in the human body, yet their roles in development, physiology, and disease are incompletely understood. Studies in C. elegans have helped identify biological functions of these receptors, as well as transduction mechanisms. Here we review advances in our understanding of Eph receptor signaling made using the C. elegans model system. PMID:23197476

Miller, Michael A.; Chin-Sang, Ian D.

2014-01-01

48

Induction of germline apoptosis in Caenorhabditis elegans.  

PubMed

RNA interference (RNAi) is an incredibly powerful tool for rapid and efficient knockdown of gene expression. This technology can be used to induce apoptosis in the germline of Caenorhabditis elegans. Genotoxic stressors such as ionizing radiation (IR), ultraviolet light, chemical mutagens (e.g., N-ethyl-N-nitrosourea [ENU]), and DNA cross-linking reagents can also be used to stimulate apoptosis. These approaches, described here, combined with the powers of in vivo imaging methods, should keep C. elegans apoptosis researchers busy for several years, sorting out how various signaling pathways influence life and death decisions in this organism. PMID:24591690

Lant, Benjamin; Derry, W Brent

2014-03-01

49

Cytological Analysis of Meiosis in Caenorhabditis elegans  

PubMed Central

The nematode Caenorhabditis elegans has emerged as an informative experimental system for analysis of meiosis, in large part because of the advantageous physical organization of meiotic nuclei as a gradient of stages within the germline. Here we provide tools for detailed observational studies of cells within the worm gonad, including techniques for light and electron microscopy. PMID:19685325

Phillips, Carolyn M.; McDonald, Kent L.; Dernburg, Abby F.

2011-01-01

50

Mitochondrial bioenergetics and disease in Caenorhabditis elegans.  

PubMed

Simple multicellular animal model systems are central to studying the complex mechanisms underlying a bewildering array of diseases involving dysfunctional mitochondria. Mutant nuclear- and mitochondrial-encoded subunits of the Caenorhabditis elegans mitochondrial respiratory chain (MRC) have been investigated, including GAS-1, NUO-1, NUO-6, MEV-1, SDHB-1, CLK-1, ISP-1, CTB-1, and ATP-2. These, as well as proteins that modify the MRC indirectly, have been studied on the molecular, cellular, and organismal levels through the variety of experimental approaches that are readily achievable in C. elegans. In C. elegans, MRC dysfunction can mimic signs and symptoms observed in human patients with primary mitochondrial disorders, such as neuromuscular deficits, developmental delay, altered anesthetic sensitivity, and increased lactate levels. Antioxidant dietary supplements, coenzyme Q substitutes, and flavin cofactors have been explored as potential therapeutic strategies. Furthermore, mutants with altered longevity have proved useful for probing the contributions of bioenergetics, reactive oxygen species, and stress responses to the process of aging. C. elegans will undoubtedly continue to provide a useful system in which to explore unanswered questions in mitochondrial biology and disease. PMID:25553447

Dancy, Beverley M; Sedensky, Margaret M; Morgan, Philip G

2015-01-01

51

Programmed Cell Death in C. elegans  

Microsoft Academic Search

Genetic screens in the hermaphrodite nematode worm Caenorhabditis elegans resulted in the identification of the basal conserved machinery of apoptosis, arguably the single most important finding for our understanding of cell death. The last two years have seen enormous progress in the elucidation of the molecular interactions that lie at the heart of this conserved machinery, along with major insights

Andrew G. Fraser

1999-01-01

52

Organogenesis of the Caenorhabditis elegans Intestine  

Microsoft Academic Search

The intestine of Caenorhabditis elegans is an epithelial tube consisting of only 20 cells and is derived clonally from a single embryonic blastomere called E. We describe the cellular events that shape the intestine. These events include cytoplasmic polarization of cells in the intestinal primordium, the intercalation of specific sets of cells, the generation of an extracellular cavity within the

Ben Leung; Greg J Hermann; James R Priess

1999-01-01

53

The invertebrate Caenorhabditis elegans biosynthesizes ascorbate.  

PubMed

l-Ascorbate, commonly known as vitamin C, serves as an antioxidant and cofactor essential for many biological processes. Distinct ascorbate biosynthetic pathways have been established for animals and plants, but little is known about the presence or synthesis of this molecule in invertebrate species. We have investigated ascorbate metabolism in the nematode Caenorhabditis elegans, where this molecule would be expected to play roles in oxidative stress resistance and as cofactor in collagen and neurotransmitter synthesis. Using high-performance liquid chromatography and gas-chromatography mass spectrometry, we determined that ascorbate is present at low amounts in the egg stage, L1 larvae, and mixed animal populations, with the egg stage containing the highest concentrations. Incubating C. elegans with precursor molecules necessary for ascorbate synthesis in plants and animals did not significantly alter ascorbate levels. Furthermore, bioinformatic analyses did not support the presence in C. elegans of either the plant or the animal biosynthetic pathway. However, we observed the complete (13)C-labeling of ascorbate when C. elegans was grown with (13)C-labeled Escherichia coli as a food source. These results support the hypothesis that ascorbate biosynthesis in invertebrates may proceed by a novel pathway and lay the foundation for a broader understanding of its biological role. PMID:25668719

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

2015-03-01

54

THE GENETICS OF CAENOR?ABDITIS ELEGANS  

Microsoft Academic Search

Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced mutants affecting behavior and morphology have been char- acterized and about one hundred genes have been defined. Mutations in 77 of these alter the movement of the animal. Estimates of the induced mutation frequency of both the visible

S. BRENNER

1974-01-01

55

CAENORHABDITIS ELEGANS AS AN ALTERNATIVE ANIMAL SPECIES  

Microsoft Academic Search

Caenorhabditis elegans has proven useful in toxicity testing of known toxicants, but its potential for assessing the toxicity of new pharmaceuticals is relatively unexplored. In this study the procedures used in aquatic testing of toxicants were modified to permit testing of small amounts (<40 mg) of gadolinium-based magnetic resonance imaging (MRI) compounds. Five blinded compounds were tested. The toxicity of

Phillip L. Williams; Gary L. Anderson; John L. Johnstone; Adrian D. Nunn; Michael F. Tweedle; Paul Wedeking

2000-01-01

56

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

57

The embryonic muscle transcriptome of Caenorhabditis elegans  

PubMed Central

Background The force generating mechanism of muscle is evolutionarily ancient; the fundamental structural and functional components of the sarcomere are common to motile animals throughout phylogeny. Recent evidence suggests that the transcription factors that regulate muscle development are also conserved. Thus, a comprehensive description of muscle gene expression in a simple model organism should define a basic muscle transcriptome that is also found in animals with more complex body plans. To this end, we applied microarray profiling of Caenorhabtidis elegans cells (MAPCeL) to muscle cell populations extracted from developing C. elegans embryos. Results We used fluorescence-activated cell sorting to isolate myo-3::green fluorescent protein (GFP) positive muscle cells, and their cultured derivatives, from dissociated early C. elegans embryos. Microarray analysis identified 7,070 expressed genes, 1,312 of which are enriched in the myo-3::GFP positive cell population relative to the average embryonic cell. The muscle enriched gene set was validated by comparisons with known muscle markers, independently derived expression data, and GFP reporters in transgenic strains. These results confirm the utility of MAPCeL for cell type specific expression profiling and reveal that 60% of these transcripts have human homologs. Conclusion This study provides a comprehensive description of gene expression in developing C. elegans embryonic muscle cells. The finding that more than half of these muscle enriched transcripts encode proteins with human homologs suggests that mutant analysis of these genes in C. elegans could reveal evolutionarily conserved models of muscle gene function, with ready application to human muscle pathologies. PMID:17848203

Fox, Rebecca M; Watson, Joseph D; Von Stetina, Stephen E; McDermott, Joan; Brodigan, Thomas M; Fukushige, Tetsunari; Krause, Michael; Miller, David M

2007-01-01

58

Hormetic effect of methylmercury on Caenorhabditis elegans  

PubMed Central

Research has demonstrated the toxic effects of methylmercury (MeHg), yet molecular mechanisms underlying its toxicity are not completely understood. Caenorhabditis elegans (C. elegans) offers a unique biological model to explore mechanisms of MeHg toxicity given many advantages associated with its ease of use and genetic power. Since our previous work indicated neurotoxic resistance of C. elegans to MeHg, the present study was designed to examine molecular mechanisms associated with this resistance. We hypothesized MeHg would induce expression of gst, hsp or mtl in vivo since glutathione (GSH), heat shock proteins (HSPs), and metallothioneins (MTs) have shown involvement in MeHg toxicity. Our studies demonstrated a modest, but significant increase in fluorescence in gst-4::GFP and mtl-1::GFP strains at an acute, low L1 MeHg exposure, whereas chronic L4 MeHg exposure induced expression of gst-4::GFP and hsp-4::GFP. Knockout gst-4 animals showed no alterations in lethality sensitivity compared to wildtype animals whereas mtl knockouts displayed increased sensitivity to MeHg exposure. GSH levels were increased by acute MeHg treatment and depleted with chronic exposure. We also demonstrate that MeHg induces hormesis, a phenotype whereby a sublethal exposure to MeHg rendered C. elegans resistant to subsequent exposure to the organometal. The involvement of gst-4, hsp-4, mtl-1, and mtl-2 in hormesis was examined. An increase in gst-4::GFP expression after a low-dose acute exposure to MeHg indicated that gst-4 may be involved in this response. Our results implicate GSH, HSPs, and MTs in protecting C. elegans from MeHg toxicity and show a potential role of gst-4 in MeHg-induced hormesis. PMID:20691719

Helmcke, Kirsten J.; Aschner, Michael

2010-01-01

59

Basic Caenorhabditis elegans Methods: Synchronization and Observation  

PubMed Central

Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism 1. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years 2. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved 3. C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage 4,5 together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology 6, aging 7,8, stem cell biology 9 and germ line biology 10. An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them. PMID:22710399

Porta-de-la-Riva, Montserrat; Fontrodona, Laura; Villanueva, Alberto; Cerón, Julián

2012-01-01

60

Hormetic effect of methylmercury on Caenorhabditis elegans  

SciTech Connect

Research has demonstrated the toxic effects of methylmercury (MeHg), yet molecular mechanisms underlying its toxicity are not completely understood. Caenorhabditis elegans (C. elegans) offers a unique biological model to explore mechanisms of MeHg toxicity given many advantages associated with its ease of use and genetic power. Since our previous work indicated neurotoxic resistance of C. elegans to MeHg, the present study was designed to examine molecular mechanisms associated with this resistance. We hypothesized MeHg would induce expression of gst, hsp or mtl in vivo since glutathione (GSH), heat shock proteins (HSPs), and metallothioneins (MTs) have shown involvement in MeHg toxicity. Our studies demonstrated a modest, but significant increase in fluorescence in gst-4::GFP and mtl-1::GFP strains at an acute, low L1 MeHg exposure, whereas chronic L4 MeHg exposure induced expression of gst-4::GFP and hsp-4::GFP. Knockout gst-4 animals showed no alterations in lethality sensitivity compared to wildtype animals whereas mtl knockouts displayed increased sensitivity to MeHg exposure. GSH levels were increased by acute MeHg treatment and depleted with chronic exposure. We also demonstrate that MeHg induces hormesis, a phenotype whereby a sublethal exposure to MeHg rendered C. elegans resistant to subsequent exposure to the organometal. The involvement of gst-4, hsp-4, mtl-1, and mtl-2 in hormesis was examined. An increase in gst-4::GFP expression after a low-dose acute exposure to MeHg indicated that gst-4 may be involved in this response. Our results implicate GSH, HSPs, and MTs in protecting C. elegans from MeHg toxicity and show a potential role of gst-4 in MeHg-induced hormesis.

Helmcke, Kirsten J., E-mail: Kirsten.J.Helmcke@gmail.com; Aschner, Michael, E-mail: Michael.Aschner@vanderbilt.ed

2010-10-15

61

Beyond VaR: from measuring risk to managing risk  

Microsoft Academic Search

The paper examines tools for managing, as opposed to simply monitoring, a portfolio's value-at-risk (VaR). These tools include the calculation of VaR contribution, marginal VaR and trade risk profiles. We first review the parametric, or delta-normal versions of these tools and then extend them to the simulation based, or nonparametric case. We analyze two sample portfolios: one, consisting of foreign

H. Mausser; D. Rosen

1999-01-01

62

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.

63

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

64

Evaluation of morphological and molecular variation in Plantago asiatica var. densiuscula , with special reference to the systematic treatment of Plantago asiatica var. yakusimensis  

Microsoft Academic Search

Morphological and molecular variations in Plantago asiatica L. var. densiuscula Pilg. were analyzed to evaluate the genetic basis for recognizing the dwarf variety P. asiatica var. yakusimensis (Masam.) Ohwi. Considerable variation in the leaf size of P. asiatica var. densiuscula was observed, and no morphological discontinuities were found between the dwarf types of P. asiatica var. densiuscula and P. asiatica

Naoko Ishikawa; Jun Yokoyama; Hiroshi Ikeda; Eriko Takabe; Hirokazu Tsukaya

2006-01-01

65

The development of RAPD and microsatellite markers in lodgepole pine (Pinus contorta var.  

E-print Network

The development of RAPD and microsatellite markers in lodgepole pine (Pinus contorta var. latifolia pine (Pinus contorta var. latifolia) have been developed. We detected 52 decameric oligonucleotides polymorphism, RAPD, microsatellite, SSR, Pinus contorta var. latifolia. Résumé : Deux types de marqueurs

Macdonald, Ellen

66

Metal-induced neurodegeneration in C. elegans  

PubMed Central

The model species, Caenorhabditis elegans, has been used as a tool to probe for mechanisms underlying numerous neurodegenerative diseases. This use has been exploited to study neurodegeneration induced by metals. The allure of the nematode comes from the ease of genetic manipulation, the ability to fluorescently label neuronal subtypes, and the relative simplicity of the nervous system. Notably, C. elegans have approximately 60–80% of human genes and contain genes involved in metal homeostasis and transport, allowing for the study of metal-induced degeneration in the nematode. This review discusses methods to assess degeneration as well as outlines techniques for genetic manipulation and presents a comprehensive survey of the existing literature on metal-induced degeneration studies in the worm. PMID:23730287

Chen, Pan; Martinez-Finley, Ebany J.; Bornhorst, Julia; Chakraborty, Sudipta; Aschner, Michael

2013-01-01

67

Mechanisms of iron metabolism in Caenorhabditis elegans  

PubMed Central

Iron is involved in many biological processes essential for sustaining life. In excess, iron is toxic due to its ability to catalyze the formation of free radicals that damage macromolecules. Organisms have developed specialized mechanisms to tightly regulate iron uptake, storage and efflux. Over the past decades, vertebrate model organisms have led to the identification of key genes and pathways that regulate systemic and cellular iron metabolism. This review provides an overview of iron metabolism in the roundworm Caenorhabditis elegans and highlights recent studies on the role of hypoxia and insulin signaling in the regulation of iron metabolism. Given that iron, hypoxia and insulin signaling pathways are evolutionarily conserved, C. elegans provides a genetic model organism that promises to provide new insights into mechanisms regulating mammalian iron metabolism. PMID:24904417

Anderson, Cole P.; Leibold, Elizabeth A.

2014-01-01

68

Programmed Cell Death in C. elegans  

Microsoft Academic Search

Studies in the nematode Caenorhabditis elegans have established that programmed cell death is a genetically determined part of development and is controlled by a specific\\u000a set of genes. These genes have been ordered into a pathway through genetic analyses. This cell death pathway is evolutionarily\\u000a conserved and provides a basis for understanding programmed cell death in more complex organisms, including

Monica Darland-Ransom; Yi-Chun Wu; Ding Xue

69

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

70

Microbial transformation of dehydroandrographolide by Cunninghamella elegans.  

PubMed

The biotransformation of dehydroandrographolide (1) by Cunninghamella elegans was performed and four transformed products were obtained. Based on their extensive spectral data, the structures of these metabolites were identified as 3-oxo-dehydroandrographolide (2), 3-oxo-2beta-hydroxy-dehydroandrographolide (3), 3-oxo-8beta,17alpha-epoxydehydroandrographolide (4), 3,19-dihydroxy-7,11,13-ent-labdatrien-15,16-olide (5), respectively. Among them, products 3-5 are new compounds. PMID:19219734

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

2009-01-01

71

Biotransformation of cinobufagin by Cunninghamella elegans.  

PubMed

Cunninghamella elegans has been employed for the biotransformation of cinobufagin to afford 5 metabolites. The structures of the transformation products have been characterized as 12alpha-hydroxybufagin, 11alpha-hydroxybufagin, 12beta-hydroxy-desacetylcinobufagin, 3-oxo-12alpha-hydroxybufagin and 12beta-hydroxybufagin. Products 12alpha-hydroxybufagin and 11alpha-hydroxybufagin are new compounds. In vitro both the biotransformation products and cinobufagin all showed cytotoxic activities against HeLa cells. PMID:17456977

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

2007-04-01

72

Steroidal saponins from Paris polyphylla var. yunnanensis.  

PubMed

Eleven steroidal saponins, along with seven known steroidal saponins, were isolated from rhizomes of Paris polyphylla var. yunnanensis. Their chemical structures were elucidated on the basis of spectroscopic analyses and acid hydrolysis. Two of these compounds contained a spirostanol saponin aglycone, hitherto unknown in Nature. The isolated compounds were tested for their cytotoxic effects on human nasopharyngeal carcinoma epithelial (CNE) cells, and seven compounds displayed more potent inhibitory effects than cisplatin (the positive control). One compound with diosgenin and tetrasaccharide moieties possessed the strongest inhibitory effect on CNE cells through the induction of apoptosis and cell cycle arrest. PMID:22748777

Wu, Xia; Wang, Lei; Wang, Hui; Dai, Yi; Ye, Wen-Cai; Li, Yao-Lan

2012-09-01

73

Dissection of Genetic Pathways in C. elegans  

PubMed Central

With unique genetic and cell biological strengths, C. elegans has emerged as a powerful model system for studying many biological processes. These processes are regulated by complex genetic networks consisting of arrays of genes. Identifying those genes and organizing them into genetic pathways are two major steps towards understanding the mechanisms that regulate biological events. Forward genetic screens with various designs are a traditional approach for identifying candidate genes. The completion of the genome sequencing in C. elegans and the advent of high-throughput experimental techniques have led to the development of two additional powerful approaches: functional genomics and systems biology. Genes that are identified by all these approaches can be ordered into interacting pathways through a variety of strategies, involving genetics, cell biology, biochemistry and functional genomics, to gain a complete understanding of how gene regulatory networks control a particular biological process. The aim of this review is to provide an overview of the approaches available to identify and construct the genetic pathways using C. elegans. PMID:22118276

Wang, Zheng; Sherwood, David R.

2014-01-01

74

Maximally informative foraging by Caenorhabditis elegans  

PubMed Central

Animals have evolved intricate search strategies to find new sources of food. Here, we analyze a complex food seeking behavior in the nematode Caenorhabditis elegans (C. elegans) to derive a general theory describing different searches. We show that C. elegans, like many other animals, uses a multi-stage search for food, where they initially explore a small area intensively (‘local search’) before switching to explore a much larger area (‘global search’). We demonstrate that these search strategies as well as the transition between them can be quantitatively explained by a maximally informative search strategy, where the searcher seeks to continuously maximize information about the target. Although performing maximally informative search is computationally demanding, we show that a drift-diffusion model can approximate it successfully with just three neurons. Our study reveals how the maximally informative search strategy can be implemented and adopted to different search conditions. DOI: http://dx.doi.org/10.7554/eLife.04220.001 PMID:25490069

Calhoun, Adam J; Chalasani, Sreekanth H; Sharpee, Tatyana O

2014-01-01

75

Neuronal aging: learning from C. elegans  

PubMed Central

The heterogeneity and multigenetic nature of nervous system aging make modeling of it a formidable task in mammalian species. The powerful genetics, simple anatomy and short life span of the nematode Caenorhabditis elegans offer unique advantages in unraveling the molecular genetic network that regulates the integrity of neuronal structures and functions during aging. In this review, we first summarize recent breakthroughs in the morphological and functional characterization of C. elegans neuronal aging. Age-associated morphological changes include age-dependent neurite branching, axon beading or swelling, axon defasciculation, progressive distortion of the neuronal soma, and early decline in presynaptic release function. We then discuss genetic pathways that modulate the speed of neuronal aging concordant with alteration in life span, such as insulin signaling, as well as cell-autonomous factors that promote neuronal integrity during senescence, including membrane activity and JNK/MAPK signaling. As a robust genetic model for aging, insights from C. elegans neuronal aging studies will contribute to our mechanistic understanding of human brain aging. PMID:24325838

2013-01-01

76

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

77

Etude compare de Penicillium roquejorii et P. verrucosum var. cyclopium  

E-print Network

Etude comparée de Penicillium roquejorii et P. verrucosum var. cyclopium Le Lait (1981),61, 370 fabrication des souches de Penicillium roque- [orti. De nos jours les fromagers achètent ce levain fongique on trouve Penicillium verrucosum var. cyclopium morphologique- ment voisin de P. roquejorti avec lequel il

Paris-Sud XI, Université de

78

Caenorhabditis elegans chemical biology: lessons from small molecules  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

79

Locomotion Control of Caenorhabditis elegans through Confinement Felix Lebois,  

E-print Network

#12;Locomotion Control of Caenorhabditis elegans through Confinement Fe´lix Lebois, Pascal Sauvage organism Caenorhabditis elegans shows two distinct locomotion patterns in laboratory situations: it swims in the regulation of locomotion and in the gait selection. Using an original device, we present what to our

Hersen, Pascal - Laboratoire Matière et Systèmes Complexes, Université Paris 7

80

Katz model prediction of Caenorhabditis elegans mutagenesis on STS-42  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

81

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

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

2012-01-01

82

Function and regulation of TRP family channels in C. elegans  

Microsoft Academic Search

Seventeen transient receptor potential (TRP) family proteins are encoded by the C. elegans genome, and they cover all of the seven TRP subfamilies, including TRPC, TRPV, TRPM, TRPN, TRPA, TRPP, and TRPML. Classical\\u000a forward and reverse genetic screens have isolated mutant alleles in every C. elegans trp gene, and their characterizations have revealed novel functions and regulatory mechanisms of TRP

Rui Xiao; X. Z. Shawn Xu

2009-01-01

83

C. elegans as a model organism Jonathan Hodgkin  

E-print Network

. elegans research papers per year #12;Nobel Prizes for C. elegans research Nobel Prize for Physiology or Medicine, 2002 H. Robert Horvitz John Sulston Sydney Brenner Nobel Prize for Physiology or Medicine, 2006 Andrew Fire Craig Mello Nobel Prize for Chemistry, 2008 Martin Chalfie (with Osamu Shimamura and Roger

Goldschmidt, Christina

84

Cadherin Superfamily Proteins in Caenorhabditis elegans and Drosophila melanogaster  

E-print Network

of Caenorhabditis elegans and Drosophila melanogaster. Hidden Markov models of cadherin domains were matchedCadherin Superfamily Proteins in Caenorhabditis elegans and Drosophila melanogaster Emma Hill1 projects, determination of the full reper- toire of cadherins available to an organism is possible and here

Hill, Emma

85

INHIBITION OF STEROL METABOLISM IN CAENORHABDITIS ELEGANS BY AY-9944  

Technology Transfer Automated Retrieval System (TEKTRAN)

Caenorhabditis elegans and some other nematodes are capable of attaching a methyl group to the nucleus of sterols at the C-4 position. In C. elegans, 4-methylcholest-8(14)-enol is the most abundant 4-methylsterol produced, and smaller quantities of 4-methylcholest-7-enol also occur. The purpose of...

86

Metformin Retards Aging in C. elegans by Altering Microbial Folate  

E-print Network

Metformin Retards Aging in C. elegans by Altering Microbial Folate and Methionine Metabolism Filipe: david.gems@ucl.ac.uk http://dx.doi.org/10.1016/j.cell.2013.02.035 SUMMARY The biguanide drug metformin uncertain. Metformin also increases lifespan in Caenorhabditis elegans co- cultured with Escherichia coli

Gems, David

87

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

88

Caenorhabditis elegans swimming in a saturated particulate system  

NASA Astrophysics Data System (ADS)

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

Jung, Sunghwan

2010-03-01

89

Genetic maps for Pinus elliottii var. elliottii and P. caribaea var. hondurensis using AFLP and microsatellite markers.  

PubMed

Genetic maps for individual Pinus elliottii var. elliottii and P. caribaea var. hondurensis trees were generated using a pseudo-testcross mapping strategy. A total of 329 amplified fragment length polymorphic (AFLP) and 12 microsatellite markers were found to segregate in a sample of 93 interspecfic F(1) progeny. The male P. caribaea var. hondurensis parent was more heterozygous than the female P. elliottii var. elliottii parent with 19% more markers segregating on the male side. Framework maps were constructed using a LOD 5 threshold for grouping and interval support threshold of LOD 2. The framework map length for the P. elliottii var. elliottii megagametophyte parent (1,170 cM Kosambi; 23 linkage groups) was notably smaller than the P. caribaea var. hondurensis pollen parent (1,658 cM Kosambi; 27 linkage groups). The difference in map lengths was assumed to be due to sex-related recombination variation, which has been previously reported for pines, as the difference in map lengths not be accounted for by the larger number of markers mapping to the P. caribaea var. hondurensis parent - 109 compared with 78 in P. elliottii var. elliottii parent. Based on estimated genome sizes for these species, the framework maps for P. elliottii var. elliottii and P. caribaea var. hondurensis covered 82% and 88% of their respective genomes. The pseudo-testcross strategy was extended to include AFLP and microsatellite markers in an intercross configuration. These comprehensive maps provided further genome coverage, 1,548 and 1,828 cM Kosambi for P. elliottii var. elliottii and P. caribaea var. hondurensis, respectively, and enabled homologous linkage groups to be identified in the two parental maps. Homologous linkage groups were identified for 11 out of 24 P. elliottii var. elliottii and 10 out of 25 P. caribaea var. hondurensis groups. A higher than expected level of segregation distortion was found for both AFLP and microsatellite markers. An explanation for this segregation distortion was not clear, but it may be at least in part due to genetic mechanisms for species isolation in this wide cross. PMID:12750783

Shepherd, M; Cross, M; Dieters, M J; Henry, R

2003-05-01

90

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

91

Immunoglobulin superfamily proteins in Caenorhabditis elegans.  

PubMed

The predicted proteins of the genome of Caenorhabditis elegans were analysed 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 eukaryotes too. This is because members of the superfamily are involved in a variety of functions including cell-cell recognition, cell-surface receptors, muscle structure and, in higher organisms, the immune system. Sixty-four proteins with 488 I set IgSF domains were identified largely by using Hidden Markov models. The domain architectures of the protein products of these 64 genes are described. Twenty-one of these had been characterised previously. We show that another 25 are related to proteins of known function. The C. elegans IgSF proteins can be classified into five broad categories: muscle proteins, protein kinases and phosphatases, three categories of proteins involved in the development of the nervous system, leucine-rich repeat containing proteins and proteins without homologues of known function, of which there are 18. The 19 proteins involved in nervous system development that are not kinases or phosphatases are homologues of neuroglian, axonin, NCAM, wrapper, klingon, ICCR and nephrin or belong to the recently identified zig gene family. Out of the set of 64 genes, 22 are on the X chromosome. This study should be seen as an initial description of the IgSF repertoire in C. elegans, because the current gene definitions may contain a number of errors, especially in the case of long sequences, and there may be IgSF genes that have not yet been detected. However, the proteins described here do provide an overview of the bulk of the repertoire of immunoglobulin superfamily members in C. elegans, a framework for refinement and extension of the repertoire as gene and protein definitions improve, and the basis for investigations of their function and for comparisons with the repertoires of other organisms. PMID:10698639

Teichmann, S A; Chothia, C

2000-03-10

92

Transformation of Amoxapine by Cunninghamella elegans  

PubMed Central

We examined Cunninghamella elegans to determine its ability to transform amoxapine, a tricyclic antidepressant belonging to the dibenzoxazepine class of drugs. Approximately 57% of the exogenous amoxapine was metabolized to three metabolites that were isolated by high-performance liquid chromatography and were identified by nuclear magnetic resonance and mass spectrometry as 7-hydroxyamoxapine (48%), N-formyl-7-hydroxyamoxapine (31%), and N-formylamoxapine (21%). 7-Hydroxyamoxapine, a mammalian metabolite with biological activity, now can be produced in milligram quantities for toxicological evaluation. PMID:10919836

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

2000-01-01

93

The basking behavior of Trachemys scripta elegans  

E-print Network

of attached styrofoam floats. While this technique was effective for monitoring 26 sea turtles in the open ocean (Ferner, 1979), it was impractical for turtles in a farm pond full of vegetation and sunken auto parts. The floats continually caught on other...THE BASKING BEHAVIOR OFT~RACHEMY BCIHFTA~ELEGAN A Thesis LISA MAUREEN MCDONALD Submitted to the Office of Graduate Studies of Texas ABiM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1992...

McDonald, Lisa Maureen

1992-01-01

94

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

95

Characterization of the effects of methylmercury on Caenorhabditis elegans  

PubMed Central

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. PMID:19341752

Helmcke, Kirsten J.; Syversen, Tore; Miller, David M.; Aschner, Michael

2009-01-01

96

Caenorhabditis elegans as a model for intracellular pathogen infection  

PubMed Central

Summary The genetically tractable nematode Caenorhabditis elegans is a convenient host for studies of pathogen infection. With the recent identification of two types of natural intracellular pathogens of C. elegans, this host now provides the opportunity to examine interactions and defence against intracellular pathogens in a whole-animal model for infection. C. elegans is the natural host for a genus of microsporidia, which comprise a phylum of fungal-related pathogens of widespread importance for agriculture and medicine. More recently, C. elegans has been shown to be a natural host for viruses related to the Nodaviridae family. Both microsporidian and viral pathogens infect the C. elegans intestine, which is composed of cells that share striking similarities to human intestinal epithelial cells. Because C. elegans nematodes are transparent, these infections provide a unique opportunity to visualize differentiated intestinal cells in vivo during the course of intracellular infection. Together, these two natural pathogens of C. elegans provide powerful systems in which to study microbial pathogenesis and host responses to intracellular infection. PMID:23617769

Balla, Keir M.; Troemel, Emily R.

2014-01-01

97

Caenorhabditis elegans as a model for intracellular pathogen infection.  

PubMed

The genetically tractable nematode Caenorhabditis elegans is a convenient host for studies of pathogen infection. With the recent identification of two types of natural intracellular pathogens of C. elegans, this host now provides the opportunity to examine interactions and defence against intracellular pathogens in a whole-animal model for infection. C. elegans is the natural host for a genus of microsporidia, which comprise a phylum of fungal-related pathogens of widespread importance for agriculture and medicine. More recently, C. elegans has been shown to be a natural host for viruses related to the Nodaviridae family. Both microsporidian and viral pathogens infect the C. elegans intestine, which is composed of cells that share striking similarities to human intestinal epithelial cells. Because C. elegans nematodes are transparent, these infections provide a unique opportunity to visualize differentiated intestinal cells in vivo during the course of intracellular infection. Together, these two natural pathogens of C. elegans provide powerful systems in which to study microbial pathogenesis and host responses to intracellular infection. PMID:23617769

Balla, Keir M; Troemel, Emily R

2013-08-01

98

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.

99

Forward-looking information in VAR models and the price puzzle  

Microsoft Academic Search

With a view to addressing the major disadvantage of the VAR model, namely the inadequate description of the central bank reaction function, we propose a VAR specification that proves successful in solving the price puzzle featuring in monetary VARs for the US. This specification consists in augmenting a standard VAR with two forward-looking variables: the federal funds futures rate (or

Sophocles N. Brissimis; Nicholas S. Magginas

2006-01-01

100

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

2008-01-01

101

Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.  

PubMed

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

2008-12-01

102

Biotransformation of fluorene by the fungus Cunninghamella elegans.  

PubMed Central

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

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

1993-01-01

103

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

104

Visualizing neuroblast cytokinesis during C. elegans embryogenesis.  

PubMed

This protocol describes the use of fluorescence microscopy to image dividing cells within developing Caenorhabditis elegans embryos. In particular, this protocol focuses on how to image dividing neuroblasts, which are found underneath the epidermal cells and may be important for epidermal morphogenesis. Tissue formation is crucial for metazoan development and relies on external cues from neighboring tissues. C. elegans is an excellent model organism to study tissue morphogenesis in vivo due to its transparency and simple organization, making its tissues easy to study via microscopy. Ventral enclosure is the process where the ventral surface of the embryo is covered by a single layer of epithelial cells. This event is thought to be facilitated by the underlying neuroblasts, which provide chemical guidance cues to mediate migration of the overlying epithelial cells. However, the neuroblasts are highly proliferative and also may act as a mechanical substrate for the ventral epidermal cells. Studies using this experimental protocol could uncover the importance of intercellular communication during tissue formation, and could be used to reveal the roles of genes involved in cell division within developing tissues. PMID:24686748

Wernike, Denise; van Oostende, Chloe; Piekny, Alisa

2014-01-01

105

PCH-2 regulates Caenorhabditis elegans lifespan.  

PubMed

Components or downstream targets of many signaling pathways such as Insulin/IGF-1 and TOR, as well as genes involved in cellular metabolism and bioenergetics can extend worm lifespan 20% or more. The C. elegans gene pch-2 and its homologs, including TRIP13 in humans, have been studied for their functions in cell mitosis and meiosis, but have never been implicated in lifespan regulation. Here we show that over-expression of TRIP13 in human fibroblasts confers resistance to environmental stressors such as UV radiation and oxidative stress. Furthermore, pch-2 overexpression in C. elegans extends worm lifespan, and enhances worm survival in response to various stressors. Conversely, reducing pch-2 expression with RNAi shortens worm lifespan. Additional genetic epistasis analysis indicates that the molecular mechanism of pch-2 in worm longevity is tied to functions of the sirtuin family, implying that pch-2 is another chromatin regulator for worm longevity. These findings suggest a novel function of the pch-2 gene involved in lifespan determination. PMID:25635513

Qian, Hong; Xu, Xiangru; Niklason, Laura E

2015-01-01

106

Adherens junctions in C. elegans embryonic morphogenesis.  

PubMed

Caenorhabditis elegans provides a simplified, in vivo model system in which to study adherens junctions (AJs) and their role in morphogenesis. The core AJ components-HMR-1/E-cadherin, HMP-2/?-catenin and HMP-1/?-catenin-were initially identified through genetic screens for mutants with body axis elongation defects. In early embryos, AJ proteins are found at sites of contact between blastomeres, and in epithelial cells AJ proteins localize to the multifaceted apical junction (CeAJ)-a single structure that combines the adhesive and barrier functions of vertebrate adherens and tight junctions. The apically localized polarity proteins PAR-3 and PAR-6 mediate formation and maturation of junctions, while the basolaterally localized regulator LET-413/Scribble ensures that junctions remain apically positioned. AJs promote robust adhesion between epithelial cells and provide mechanical resistance for the physical strains of morphogenesis. However, in contrast to vertebrates, C. elegans AJ proteins are not essential for general cell adhesion or for epithelial cell polarization. A combination of conserved and novel proteins localizes to the CeAJ and works together with AJ proteins to mediate adhesion. PMID:22674076

Armenti, Stephen T; Nance, Jeremy

2012-01-01

107

Insulin and germline proliferation in Caenorhabditis elegans.  

PubMed

Germline proliferation in Caenorhabditis elegans is emerging as a compelling model system for understanding the molecular basis for the developmental and physiological control of cell proliferation. This review covers the discovery and implications of the role of the insulin/IGF-like signaling pathway in germline proliferation during germline development. This pathway plays a host of important roles in C. elegans biology. Its role in germline proliferation is important to generate the proper adult stem/progenitor population and to ensure optimal fecundity. Moreover, in this role, it is restricted to reproductive (as opposed to dauer) larval stages and impinges on the G2 of the cell cycle. Two putative insulin ligands are especially important for the germline role but do not mediate signaling in other tissues. A picture is emerging of a complex web of developmentally and temporally restricted, ligand- and tissue-specific responses to insulin signaling. Avenues for future studies include the regulation of specific insulin-like ligands and the mechanisms for tissue-specific responses to them. PMID:22127237

Hubbard, E Jane Albert

2011-01-01

108

CHARACTERIZATION OF THE PARASPORAL INCLUSION OF BACILLUS THURINGIENSIS VAR. KYUSHUENSIS  

EPA Science Inventory

Bacillus thuringiensis var. kyushuensis synthesizes an irregularly shaped parasporal inclusion during sporulation. lectron microscopy revealed that the inclusions are composed of a relatively homogeneous appearing center surrounded by a thick, electron dense coating. urified incl...

109

All About Value at Risk (VaR)  

NSDL National Science Digital Library

All about Value at Risk (VaR) is a wonderful resource for those interested in this form of risk management assessment. Created by Barry Schacter, the head of Enterprise Risk Management for Caxton Corporation, this site is a clearinghouse for VaR resources including information on various forms of RiskMatrics, a vast collection of published and working papers on VaR, and links to regulatory materials from international organizations such as the Basel Committee on Banking Supervision and the International Organization of Securities Commissions, as well as from the US, Austria, Canada, Australia, the UK, and Hong Kong. Interested users may also register for a free VaR weekly electronic newsletter.

110

3-hydroxycoumarin glycosides from Alyxia reinwardti var. Lucida.  

PubMed

Investigation of the inner bark of Alyxia reinwardti var. lucida led to the isolation of two new coumarin glycosides, 1 and 2, whose structures were determined by interpretation of their spectroscopic data, particularly NMR spectroscopy. PMID:7764154

Lin, L J; Lin, L Z; Ruangrungsi, N; Cordell, G A

1993-10-01

111

Puccinia jaceae var.solstitialis teliospore priming on yellow starthistle  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

112

Mitochondrial DNA polymorphism of the yeast Saccharomyces bayanus var. uvarum.  

PubMed

Genetic relationships among forty-one strains of Saccharomyces bayanus var. uvarum isolated in different wine regions of Europe and four wild isolates were investigated by restriction analysis (RFLP) of mitochondrial DNA (mtDNA) with four restriction endonucleases, AluI, DdeI, HinfI and RsaI. No clear correlation between origin and source of isolation of S. bayanus var. uvarum strains and their mtDNA restriction profiles was found. On the whole, the mtDNA of S. bayanus var. uvarum is much less polymorphic than that of S. cerevisiae. This observation is in good agreement with results obtained by electrophoretic karyotyping. Unlike wine S cerevisiae, strains of S. bayanus var. uvarum display a low level of chromosome length polymorphism. PMID:21058508

Naumova, E S; Naumov, G I; Barrio, E; Querol, A

2010-01-01

113

[Studies on the parasites of Paris polyphylla var. yunnanensis].  

PubMed

Two bacteria and three fungi were isolated from the hypogeal stems of Paris polyphylla var. yunnanensis. The bacteria were identified as Bacillus cereus and Pseudomonas alcaligenes, and the fungi were identified as Periconia sp., Pachnocybe albida and Hormomyces paridiphilus. The results on liquid culture of B. cereus, P. alcaligenes and H. paridiphilus indicated that the colloidization and polysaccharide content increasing in hypogeal stems of P. polyphylla var. yunnanensis were due to the extracellular polysaccharide secretion of the parasitical fungus H. paridiphilus. PMID:12555422

Wang, S; Zhou, L; Li, Y; Cai, M

1999-04-01

114

Chromosome Karyotypes of Echinacea angustifolia var. angustifolia and  

Microsoft Academic Search

Chromosome karyotypes of the most commonly cultivated and medicinally used Echinacea taxa, E. angustifolia DC. var. angustifolia and E. purpurea (L.) Moench., were analyzed. The chromosomes of both taxa are medium in length, ranging from 4.12 to 5.83 µm in E. angustifolia var. angustifolia and 3.99 to 6.08 µm in E. purpurea. No abrupt length changes in the chromosomes were

Xiping Wang; Eatherley Hood; Meihua Wang; Richard Scalzo

115

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

116

Dimorphism and hydrocarbon metabolism in Yarrowia lipolytica var. indica.  

PubMed

Yarrowia lipolytica is able to metabolize high Mr hydrophobic natural compounds such as fatty acids and hydrocarbons. Characteristically, strains of Y. lipolytica can grow as populations with variable proportions of yeast and filamentous forms. In the present study, we describe the dimorphic characteristics of a variant designated as Y. lipolytica var. indica isolated from petroleum contaminated sea water and the effect of cell morphology on hydrocarbon metabolism. The variant behaved as a yeast monomorphic strain, under conditions at which terrestrial Y. lipolytica strain W29 and its derived strains, grow as almost uniform populations of mycelial cells. Using organic nitrogen sources and N-acetylglucosamine as carbon source, var. indica was able to form mycelial cells, the proportion of which increased when incubated under semi-anaerobic conditions. The cell surface characteristics of var. indica and W29 were found to be different with respect to contact angle and percent hydrophobicity. For instance, percent hydrophobicity of var. indica was 89.93 ± 1.95 while that of W29 was 70.78 ± 1.1. Furthermore, while all tested strains metabolize hydrocarbons, only var. indica was able to use it as a carbon source. Yeast cells of var. indica metabolized hexadecane with higher efficiency than the mycelial form, whereas the mycelial form of the terrestrial strain metabolized the hydrocarbon more efficiently, as occurred with the mycelial monomorphic mutant AC11, compared to the yeast monomorphic mutant AC1. PMID:24842274

Palande, A S; Kulkarni, S V; León-Ramirez, C; Campos-Góngora, E; Ruiz-Herrera, J; Deshpande, M V

2014-08-01

117

Caenorhabditis elegans behavioral genetics: where are the knobs?  

Microsoft Academic Search

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

Leon Avery

2010-01-01

118

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

119

C. Elegans and Microbeam Models in Bystander Effect Research  

E-print Network

are useful tools to characterize basic cellular and molecular responses. But to reveal the complexity of radiation responses and cellular communication, live animal models have many advantages. In recent years, models such as C. elegans and Zebrafish have...

Feng, Shaoyong

2013-08-01

120

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.

121

Imaging embryonic morphogenesis in C. elegans Jeff Hardin  

E-print Network

Imaging embryonic morphogenesis in C. elegans Jeff Hardin Department for imaging embryonic morphogenesis, including making agar mounts, capturing 4D data microscopy for intracellular imaging of cellular components during morphogenesis. I

Hardin, Jeff

122

Genetic analysis of innate immunity in Caenorhabditis elegans  

E-print Network

Pathogen resistance in Caenorhabditis elegans is a model for studying innate immunity. Several conserved activators in the p38 PMK-1 pathway have been identified and are required for pathogen resistance to the bacterium ...

Redding, Bethany Joy

2007-01-01

123

Bacterial attraction and quorum sensing inhibition in Caenorhabditis elegans exudates  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

124

Caenorhabditis elegans: An Emerging Model in Biomedical and Environmental Toxicology  

PubMed Central

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 developmental program, well-characterized genome, ease of maintenance, short and prolific life cycle, and small body size. These same features have led to an increasing use of C. elegans in toxicology, both for mechanistic studies and high-throughput screening approaches. We describe some of the research that has been carried out in the areas of neurotoxicology, genetic toxicology, and environmental toxicology, as well as high-throughput experiments with C. elegans including genome-wide screening for molecular targets of toxicity and rapid toxicity assessment for new chemicals. We argue for an increased role for C. elegans in complementing other model systems in toxicological research. PMID:18566021

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

2008-01-01

125

A Distributed Chemosensory Circuit for Oxygen Preference in C. elegans  

Microsoft Academic Search

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

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

2006-01-01

126

Genomic response of the nematode Caenorhabditis elegans to spaceflight  

PubMed Central

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

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

2008-01-01

127

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.; BRÜSCHWEILER, RAFAEL; VIVANCO, JORGE M.; EDISON, ARTHUR S.

2014-01-01

128

The Geometry of Locomotive Behavioral States in C. elegans  

PubMed Central

We develop a new hidden Markov model-based method to analyze C elegans locomotive behavior and use this method to quantitatively characterize behavioral states. In agreement with previous work, we find states corresponding to roaming, dwelling, and quiescence. However, we also find evidence for a continuum of intermediate states. We suggest that roaming, dwelling, and quiescence may best be thought of as extremes which, mixed in any proportion, define the locomotive repertoire of C elegans foraging and feeding behavior. PMID:23555813

Bjorness, Theresa; Greene, Robert; You, Young-Jai

2013-01-01

129

Geometrical structure of the neuronal network of Caenorhabditis elegans  

NASA Astrophysics Data System (ADS)

The neuronal network of the soil nematode Caenorhabditis elegans ( C. elegans), which is a good prototype for biological studies, is investigated. Here, the neuronal network is simplified as a graph. We use three indicators to characterize the graph; vertex degree, generalized eccentricity (GE), and complete subgraphs. The graph has the central part and the strong clustering structure. We present a simple model, which shows that the neuronal network has a high-dimensional geometrical structure.

Morita, Satoru; Oshio, Ken-ichi; Osana, Yuko; Funabashi, Yasuhiro; Oka, Kotaro; Kawamura, Kiyoshi

2001-09-01

130

Pharmacological classes that extend lifespan of Caenorhabditis elegans  

PubMed Central

Recent progress in the field of aging has resulted in ever increasing numbers of compounds that extend lifespan in Caenorhabditis elegans. Lifespan extending compounds include metabolites and synthetic compounds, as well as natural products. For many of these compounds, mammalian pharmacology is known, and for some the actual targets have been experimentally identified. In this review, we explore the data available in C. elegans to provide an overview of which pharmacological classes have potential for identification of further compounds that extend lifespan.

Carretero, Maria; Gomez-Amaro, Rafael L.; Petrascheck, Michael

2015-01-01

131

Genomic response of the nematode Caenorhabditis elegans to spaceflight  

NASA Astrophysics Data System (ADS)

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

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

132

Bacterial Attraction and Quorum Sensing Inhibition in Caenorhabditis elegans Exudates  

Microsoft Academic Search

Caenorhabditis elegans, a bacterivorous nematode, lives in complex rotting fruit, soil, and compost environments, and chemical interactions are\\u000a required for mating, monitoring population density, recognition of food, avoidance of pathogenic microbes, and other essential\\u000a ecological functions. Despite being one of the best-studied model organisms in biology, relatively little is known about the\\u000a signals that C. elegans uses to interact chemically

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

2009-01-01

133

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

134

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

135

Caenorhabditis elegans neuronal regeneration is influenced by life stage, ephrin signaling,  

E-print Network

regeneration in genetically tractable model organisms. AlCaenorhabditis elegans neuronal regeneration is influenced by life stage, ephrin signaling functional regeneration of Caenorhabditis elegans motor neurons after femtosecond laser axotomy. We report

Yanik, Mehmet Fatih

136

Metabolism of mixtures of polycyclic aromatic hydrocarbons (PAHs) by Cunninghamella elegans  

E-print Network

, Naematoloma frowardii, Phanerochaete chrysosporium, Phanerochaete laevis, Pleurotus ostreatus, Pleurotus sajor-caju, Romaria sp., Rhizoctonia solani, Trametes versicolor phenanthrene Aspergillus niger, Cunninghamella elegans..., Naematoloma frowardii, Phanerochaete chrysosporium, Phanerochaete laevis, Pleurotus ostreatus, Syncephalastrum racemosum, Trametes versicolor flouranthene Cunninghamella elegans, Naematoloma...

Olatubi, Oluwaseun Alfred

2007-04-25

137

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

138

Worm Phenotype Ontology: integrating phenotype data within and beyond the C. elegans community  

E-print Network

Drosophila melanogaster), mouse (Mus musculus) and worm (Caenorhabditis elegans). Annotations were retrieved directly from their respective model organismDrosophila melanogaster), mouse (Mus musculus) and worm (Caenorhabditis elegans). Annotations were retrieved directly from their respective model organism

Schindelman, Gary; Fernandes, Jolene S; Bastiani, Carol A; Yook, Karen; Sternberg, Paul W

2011-01-01

139

Effects of sterols on the development and aging of caenorhabditis elegans  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

140

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.

141

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

Code of Federal Regulations, 2011 CFR

...Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement...Bacillus subtilis var. amyloliquefaciens strain FZB24; exemption from the requirement...Bacillus subtilis var. amyloliquefaciens strain FZB24 in or on all agricultural...

2011-07-01

142

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Bacillus subtilis var. amyloliquefaciens strain...Exemptions From Tolerances § 180.1243 Bacillus subtilis var. amyloliquefaciens ...requirement of a tolerance for residues of the Bacillus subtilis var....

2010-07-01

143

The Caenorhabditis elegans Synthetic Multivulva Genes Prevent Ras Pathway Activation by Tightly Repressing  

E-print Network

The Caenorhabditis elegans Synthetic Multivulva Genes Prevent Ras Pathway Activation by Tightly The Caenorhabditis elegans class A and B synthetic multivulva (synMuv) genes redundantly antagonize an EGF/Ras) The Caenorhabditis elegans Synthetic Multivulva Genes Prevent Ras Pathway Activation by Tightly Repressing Global

van Oudenaarden, Alexander

144

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

145

Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans  

Microsoft Academic Search

We compared 42 phylogenetically conserved proteins from four marine sponges [Porifera] with almost the complete set of Caenorhabditis elegans proteins and all known proteins from humans. The majority of the sponge proteins are significantly more similar to human than to C. elegans orthologues\\/homologues. This finding reflects the accelerated evolutionary rate in the C. elegans lineage, since sponges split off first

VERA GAMULIN; ISABEL M MÜLLER; WERNER E. G MÜLLER

2000-01-01

146

Production & formulation of Bacillus thuringiensis var. israelensis & B. sphaericus 1593.  

PubMed

Three fermentation media each for bulk growth of B. thuringiensis var. israelensis and B. sphaericus 1593 were formulated using defatted groundnut cake (Arachis hypogea) as the first nitrogen source and gram flour (Cicer arientinum), soy bean (Glycine max) and defatted milk powder as the second nitrogen source. Medium containing gram flour showed highest toxicity (14.45 micrograms/l) in case of B. thuringiensis var. israelensis whereas medium containing milk powder was found to be highly toxic with B. sphaericus 1593 (51.39 micrograms/l). Sustained release floating pellet formulations of B. thuringiensis var. israelensis and B. sphaericus 1593 exhibited toxicity of 77 per cent and above for 42 days at a dose of 500 micrograms/l for 4th instar larvae of Culex pipiens quinquefasciatus Say. PMID:1778620

Desai, S Y; Shethna, Y I

1991-09-01

147

A Method for Evaluating Volt-VAR Optimization Field Demonstrations  

SciTech Connect

In a regulated business environment a utility must be able to validate that deployed technologies provide quantifiable benefits to the end-use customers. For traditional technologies there are well established procedures for determining what benefits will be derived from the deployment. But for many emerging technologies procedures for determining benefits are less clear and completely absent in some cases. Volt-VAR Optimization is a technology that is being deployed across the nation, but there are still numerous discussions about potential benefits and how they are achieved. This paper will present a method for the evaluation, and quantification of benefits, for field deployments of Volt-VAR Optimization technologies. In addition to the basic methodology, the paper will present a summary of results, and observations, from two separate Volt-VAR Optimization field evaluations using the proposed method.

Schneider, Kevin P.; Weaver, T. F.

2014-08-31

148

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

149

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

150

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

PubMed

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

151

Anthelmintic drugs and nematicides: studies in Caenorhabditis elegans.  

PubMed

Parasitic nematodes infect many species of animals throughout the phyla, including humans. Moreover, nematodes that parasitise plants are a global problem for agriculture. As such, these nematodes place a major burden on human health, on livestock production, on the welfare of companion animals and on crop production. In the 21st century there are two major challenges posed by the wide-spread prevalence of parasitic nematodes. First, many anthelmintic drugs are losing their effectiveness because nematode strains with resistance are emerging. Second, serious concerns regarding the environmental impact of the nematicides used for crop protection have prompted legislation to remove them from use, leaving agriculture at increased risk from nematode pests. There is clearly a need for a concerted effort to address these challenges. Over the last few decades the free-living nematode Caenorhabditis elegans has provided the opportunity to use molecular genetic techniques for mode of action studies for anthelmintics and nematicides. These approaches continue to be of considerable value. Less fruitful so far, but nonetheless potentially very useful, has been the direct use of C. elegans for anthelmintic and nematicide discovery programmes. Here we provide an introduction to the use of C. elegans as a 'model' parasitic nematode, briefly review the study of nematode control using C. elegans and highlight approaches that have been of particular value with a view to facilitating wider-use of C. elegans as a platform for anthelmintic and nematicide discovery and development. PMID:25517625

Holden-Dye, Lindy; Walker, Robert J

2014-01-01

152

Function and regulation of TRP family channels in C. elegans  

PubMed Central

Seventeen transient receptor potential (TRP) family proteins are encoded by the C. elegans genome, and they cover all of the seven TRP subfamilies, including TRPC, TRPV, TRPM, TRPN, TRPA, TRPP and TRPML. Classical forward and reverse genetic screens have isolated mutant alleles in every C. elegans trp gene, and their characterizations have revealed novel functions and regulatory mechanisms of TRP channels. For example, the TRPC channels TRP-1 and TRP-2 control nicotine-dependent behavior, while TRP-3, a sperm TRPC channel, is regulated by sperm activation and required for sperm-egg interactions during fertilization. Similar to their vertebrate counterparts, C. elegans TRPs function in sensory physiology. For instance, the TRPV channels OSM-9 and OCR-2 act in chemosensation, osmosensation and touch sensation, the TRPA member TRPA-1 regulates touch sensation, while the TRPN channel TRP-4 mediates proprioception. Some C. elegans TRPM, TRPP and TRPML members exhibit cellular functions similar to their vertebrate homologues and have provided insights into human diseases, including polycystic kidney disease, hypomagnesemia and mucolipidosis type IV. The availability of a complete set of trp gene mutants in conjunction with its facile genetics makes C. elegans a powerful model for studying the function and regulation of TRP family channels in vivo. PMID:19421772

Xiao, Rui; Xu, X. Z. Shawn

2010-01-01

153

[Iridoid glycosides from buds of Jasminum officinale L. var. grandiflorum].  

PubMed

The study on the buds of Jasminum officinale L. var. grandiflorum was carried out to look for anti-HBV constituents. The isolation and purification were performed by HPLC and chromatography on silica gel, polyamide and Sephadex LH-20 column. The structures were elucidated on the basis of physicochemical properties and spectral analysis. Six iridoid glycosides were identified as jasgranoside B (1), 6-O-methy-catalpol (2), deacetyl asperulosidic acid (3), aucubin (4), 8-dehydroxy shanzhiside (5), and loganin (6). Jasgranoside B (1) is a new compound. Compounds 2-6 were isolated from Jasminum officinale L. var. grandiflorum for the first time. PMID:22242454

Zhao, Gui-qin; Yin, Zhi-feng; Liu, Yu-cui; Li, Hong-bo

2011-10-01

154

Terpenoids and sterols from Nepeta cataria L. var. citriodora (Lamiaceae).  

PubMed

Isolation and GC/MS quantitative determination of ursolic acid in the herb of Nepeta cataria var. citriodora have been performed. The content of this compound was in the range 0.95-1.30%. Daucosterol (beta-sitosterol 3-O-beta-D-glucoside) was also isolated from the plant, in addition to small amounts of beta-sitosterol, campesterol, alpha-amyrin and beta-amyrin. The content and composition of essential oil in samples of the Nepeta cataria var. citriodora herb have been analysed as well. PMID:16193817

Klimek, Barbara; Modnicki, Daniel

2005-01-01

155

Phytologia (April 2008) 90(1) 97 DISTRIBUTION OF JUNIPERUS ASHEI VAR. ASHEI AND  

E-print Network

Phytologia (April 2008) 90(1) 97 DISTRIBUTION OF JUNIPERUS ASHEI VAR. ASHEI AND VAR. OVATA AROUND, Texas. KEY WORDS: Juniperus, J. ashei var. ovata, , essential oils, distribution, Cupressaceae Juniperus a few acres. Studies of geographic variation in Juniperus ashei have shown that the species has

Adams, Robert P.

156

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

157

Microbial pathogenesis and host defense in the nematode C. elegans.  

PubMed

Epithelial cells line the surfaces of the body, and are on the front lines of defense against microbial infection. Like many other metazoans, the nematode Caenorhabditis elegans lacks known professional immune cells and relies heavily on defense mediated by epithelial cells. New results indicate that epithelial defense in C. elegans can be triggered through detection of pathogen-induced perturbation of core physiology within host cells and through autophagic defense against intracellular and extracellular pathogens. Recent studies have also illuminated a diverse array of pathogenic attack strategies used against C. elegans. These findings are providing insight into the underpinnings of host/pathogen interactions in a simple animal host that can inform studies of infectious diseases in humans. PMID:25461579

Cohen, Lianne B; Troemel, Emily R

2015-02-01

158

The Caenorhabditis elegans nicotinamidase PNC-1 enhances survival.  

PubMed

In yeast, increasing the copy number of the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase Sir2 extends lifespan, which can be inhibited by nicotinamide (Nam), the end-product of Sir2-mediated NAD-breakdown. Furthermore, the yeast pyrazinamidase/nicotinamidase PNC-1 can extend yeast lifespan by converting Nam. In Caenorhabditis elegans (C. elegans), increased dosage of the gene encoding SIR-2.1 also increases lifespan. Here, we report that knockdown of the C. elegans homologue of yeast PNC-1 as well as growing worms on Nam-containing medium significantly decreases adult lifespan. Accordingly, increased gene dosage of pnc-1 increases adult survival under conditions of oxidative stress. These data show for the first time the involvement of PNC-1/Nam in the survival of a multicellular organism and may also contribute to our understanding of lifespan regulation in mammals. PMID:17335870

van der Horst, Armando; Schavemaker, Jolanda M; Pellis-van Berkel, Wendy; Burgering, Boudewijn M T

2007-04-01

159

Developmental genetics of the Caenorhabditis elegans pharynx  

PubMed Central

The Caenorhabditis elegans pharynx is a rhythmically pumping organ composed initially of 80 cells that, through fusions, amount to 62 cells in the adult worm. During the first 100 min of development, most future pharyngeal cells are born and gather into a double-plate primordium surrounded by a basal lamina. All pharyngeal cells express the transcription factor PHA-4, of which the concentration increases throughout development, triggering a sequential activation of genes with promoters responding differentially to PHA-4 protein levels. The oblong-shaped pharyngeal primordium becomes polarized, many cells taking on wedge shapes with their narrow ends toward the center, hence forming an epithelial cyst. The primordium then elongates, and reorientations of the cells at the anterior and posterior ends form the mouth and pharyngeal-intestinal openings, respectively. The 20 pharyngeal neurons establish complex but reproducible trajectories using ‘fishing line’ and growth cone-driven mechanisms, and the gland cells also similarly develop their processes. The genetics behind many fate decisions and morphogenetic processes are being elucidated, and reveal the pharynx to be a fruitful model for developmental biologists. PMID:25262818

Pilon, Marc

2014-01-01

160

Caenorhabditis elegans vulval cell fate patterning  

NASA Astrophysics Data System (ADS)

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

Félix, Marie-Anne

2012-08-01

161

Phenanthrene bioaccumulation in the nematode Caenorhabditis elegans.  

PubMed

The contribution of food to the bioaccumulation of xenobiotics and hence toxicity is still an ambiguous issue. It is becoming more and more evident that universal statements cannot be made, but that the relative contribution of food-associated xenobiotics in bioaccumulation depends on species, substance, and environmental conditions. Yet, small-sized benthic or soil animals such as nematodes have largely been disregarded so far. Bioaccumulation of the polycyclic aromatic hydrocarbon phenanthrene in the absence and presence of bacterial food was measured in the nematode Caenorhabditis elegans. Elimination of phenanthrene in the nematodes was biphasic, suggesting that there was a slowly exchanging pool within the nematodes or that biotransformation of phenanthrene took place. Even with food present, dissolved phenanthrene was still the major contributor to bioaccumulated compound in nematode tissues, whereas the diet only contributed about 9%. Toxicokinetic parameters in the treatment without food were different from the ones of the treatment with bacteria, possibly because nematodes depleted their lipid reserves during starvation. PMID:25607770

Spann, Nicole; Goedkoop, Willem; Traunspurger, Walter

2015-02-01

162

Functional Genomic Analysis of C. elegans Molting  

PubMed Central

Although the molting cycle is a hallmark of insects and nematodes, neither the endocrine control of molting via size, stage, and nutritional inputs nor the enzymatic mechanism for synthesis and release of the exoskeleton is well understood. Here, we identify endocrine and enzymatic regulators of molting in C. elegans through a genome-wide RNA-interference screen. Products of the 159 genes discovered include annotated transcription factors, secreted peptides, transmembrane proteins, and extracellular matrix enzymes essential for molting. Fusions between several genes and green fluorescent protein show a pulse of expression before each molt in epithelial cells that synthesize the exoskeleton, indicating that the corresponding proteins are made in the correct time and place to regulate molting. We show further that inactivation of particular genes abrogates expression of the green fluorescent protein reporter genes, revealing regulatory networks that might couple the expression of genes essential for molting to endocrine cues. Many molting genes are conserved in parasitic nematodes responsible for human disease, and thus represent attractive targets for pesticide and pharmaceutical development. PMID:16122351

Frand, Alison R; Russel, Sascha

2005-01-01

163

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

164

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

165

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

166

Regulation of the X chromosomes in Caenorhabditis elegans.  

PubMed

Dosage compensation, which regulates the expression of genes residing on the sex chromosomes, has provided valuable insights into chromatin-based mechanisms of gene regulation. The nematode Caenorhabditis elegans has adopted various strategies to down-regulate and even nearly silence the X chromosomes. This article discusses the different chromatin-based strategies used in somatic tissues and in the germline to modulate gene expression from the C. elegans X chromosomes and compares these strategies to those used by other organisms to cope with similar X-chromosome dosage differences. PMID:24591522

Strome, Susan; Kelly, William G; Ercan, Sevinc; Lieb, Jason D

2014-03-01

167

Analysis of Power System Stability Enhancement by Static VAR Compensators  

Microsoft Academic Search

The paper presents a fundamental analysis of the application of static VAr compensators (SVC) for stabilizing power systems. Basic SVC control strategies are examined in terms of enhancing the dynamic and transient stabilities, improving tieline transmission capacity and damping power oscillations. Synchronizing and damping torque contributions of the SVC are determined for different controls. The analysis is supplemented by digital

A. E. Hammad

1986-01-01

168

A flavone diglycoside from Cirsium japonicum var. ussuriense  

Microsoft Academic Search

Chromatographic separation of the butanol-soluble part of the methanol extract of whole plants of Cirsium japonicum var. ussuriense resulted in the isolation of a new flavonoid, hispidulin 7-neohesperidoside, together with the known cirsimaritin 4?-glucoside and acacetin 7-rutinoside.

Jong Cheol Park; Jong Ho Lee; Jae Sue Choi

1995-01-01

169

Research on static VAR generator based on the neural network  

Microsoft Academic Search

Along with the social requirements of power quality improvement, power quality problems are becoming the higher demands of social, reactive power compensation increasingly become the research focus. Based on neural network, non-linear mapping characteristics, puts forward a suitable for direct current control of static VAR generator detecting reactive and harmonic current method, established the neural network predictive model, and gives

Wenyan Nie; Zhonggen Wang

2011-01-01

170

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

171

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

172

Photosynthetic Redox Imbalance Governs Leaf Sectoring in the Arabidopsis thaliana Variegation Mutants immutans, spotty, var1, and var2[W  

PubMed Central

We hypothesized that chloroplast energy imbalance sensed through alterations in the redox state of the photosynthetic electron transport chain, measured as excitation pressure, governs the extent of variegation in the immutans mutant of Arabidopsis thaliana. To test this hypothesis, we developed a nondestructive imaging technique and used it to quantify the extent of variegation in vivo as a function of growth temperature and irradiance. The extent of variegation was positively correlated (R2 = 0.750) with an increase in excitation pressure irrespective of whether high light, low temperature, or continuous illumination was used to induce increased excitation pressure. Similar trends were observed with the variegated mutants spotty, var1, and var2. Measurements of greening of etiolated wild-type and immutans cotyledons indicated that the absence of IMMUTANS increased excitation pressure twofold during the first 6 to 12 h of greening, which led to impaired biogenesis of thylakoid membranes. In contrast with IMMUTANS, the expression of its mitochondrial analog, AOX1a, was transiently upregulated in the wild type but permanently upregulated in immutans, indicating that the effects of excitation pressure during greening were also detectable in mitochondria. We conclude that mutations involving components of the photosynthetic electron transport chain, such as those present in immutans, spotty, var1, and var2, predispose Arabidopsis chloroplasts to photooxidation under high excitation pressure, resulting in the variegated phenotype. PMID:19897671

Rosso, Dominic; Bode, Rainer; Li, Wenze; Krol, Marianna; Saccon, Diego; Wang, Shelly; Schillaci, Lori A.; Rodermel, Steven R.; Maxwell, Denis P.; Hüner, Norman P.A.

2009-01-01

173

Microbeam irradiation of the C. elegans nematode.  

PubMed

The understanding of complex radiation responses in biological systems, such as non-targeted effects as represented by the bystander response, can be enhanced by the use of genetically amenable model organisms. Almost all bystander studies to date have been carried out by using conventional single-cell in vitro systems, which are useful tools to characterize basic cellular and molecular responses. A few studies have been reported in monolayer explants and bystander responses have been also investigated in a three-dimensional normal human tissue system. However, despite the well-know usefulness of in vitro models, they cannot capture the complexity of radiation responses of living systems such as animal models. To carry out in vivo studies on the bystander effect we have developed a new technique to expose living organisms using proton microbeams. We report the use of a nematode C. elegans strain with a Green Fluorescent Protein (GFP) reporter for the hsp-4 heat-shock gene as an in vivo model for radiation studies. Exposing animals to heat and chemicals stressors leads to whole body increases in the hsp-4 protein reflected by enhanced fluorescence. We report here that gamma-rays also can induce stress response in a dose dependent manner. However, whole body exposure to stress agents does not allow for evaluation of distance dependent response in non targeted tissues: the so-called bystander effect. We used the RARAF microbeam to site specifically deliver 3 MeV protons to a site in the tail of young worms. GFP expression was enhanced after 24 hours in a number dependent manner at distances > 100 microm from the site of irradiation. PMID:19346684

Bertucci, Antonella; Pocock, Roger D J; Randers-Pehrson, Gerhard; Brenner, David J

2009-03-01

174

Sex determination in polyploids of Caenorhabditis elegans.  

PubMed

In Caenorhabditis elegans triploid animals with two X chromosomes (symbolized 3A;2X) are males. However, these triploid males can be feminized by making them mutant for recessive dosage compensation mutations, by adding X chromosome duplications or by microinjecting particular DNA sequences termed feminizing elements. None of these treatments affects diploid males. This study explores several aspects of these treatments in polyploids. The dosage compensation mutants exhibit a strong maternal effect, such that reduction of any of the dosage compensation gene functions in the mother leads to sex reversal of 3A;2X animals. Likewise, all X chromosome duplications tested cause both sex reversal and intersexual development of many 3A;2X animals. Microinjected feminizing element DNA does not cause extensive sex reversal, but does result in intersexual development in 3A;2X animals. Neither X chromosome duplications nor microinjected feminizing elements show that extreme maternal effect of the dosage compensation mutants, although there is indirect evidence for a maternal effect of the feminizing elements. In particular, very little feminizing element DNA needs to be microinjected in order to feminize triploid males, far less than what is needed for stable inheritance, implying that feminizing elements can work within the mother's gonad. However, even very high concentrations of microinjected feminizing elements do not affect sex determination in diploid males, suggesting that they are not part of the numerator of the X/A ratio. In addition, no pair of X chromosome duplications feminizes diploid males, suggesting that none of these duplications contains a numerator of the X/A ratio. Instead, I infer that an X-linked locus, as yet undefined, must be present in two copies for hermaphrodite development to ensue or that the two X chromosomes might interact. PMID:8070658

Meneely, P M

1994-06-01

175

Developmental Cell A Role for C. elegans Eph RTK  

E-print Network

in human cancer and is known to inhibit insulin signaling. Eph receptor tyrosine kinases (RTKs) have also and vascular system development. We show that in C. elegans, the VAB-1 Eph kinase domain physically interacts lipid phosphatase substrate is PIP3, which can activate AKT signaling, leading to increased cell

Chin-Sang, Ian

176

Concentration dependent differential activity of signalling molecules in Caenorhabditis elegans  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

177

The art and design of genetic screens: Caenorhabditis elegans  

Microsoft Academic Search

The nematode Caenorhabditis elegans was chosen as a model genetic organism because its attributes, chiefly its hermaphroditic lifestyle and rapid generation time, make it suitable for the isolation and characterization of genetic mutants. The most important challenge for the geneticist is to design a genetic screen that will identify mutations that specifically disrupt the biological process of interest. Since 1974,

Erik M. Jorgensen; Susan E. Mango

2002-01-01

178

RESEARCH ARTICLE Open Access Pathogen-induced Caenorhabditis elegans  

E-print Network

of development of Caenorhabditis elegans larvae fed with different bacterial strains on stress resistance to nematodes. Exposure to the pathogen during development did not affect larval survival. However, the development of nematodes on the pathogenic bacterial strains increased lifespan of adult nematodes exposed

Paris-Sud XI, Université de

179

Fine structure of the coelomic epithelium of Sagitta elegans (Chaetognatha)  

Microsoft Academic Search

The coelomic space in the trunk of the arrow worm Sagitta elegans is lined by a thin epithelium, which may be termed coelomic epithelium. The visceral part of this epithelium is composed of flat cells characterized by thin and thick myofilaments, which constitute the circular musculature of the gut. In addition mitochondria, rough ER, and smooth walled cisterns, as well

Ulrich Welsch; Volker Storch

1982-01-01

180

Small-molecule mechanism of action studies in Caenorhabditis elegans.  

PubMed

A general protocol for exogenous small-molecule pull-down experiments with Caenorhabditis elegans is described; it provides a link between small-molecule screens in worms and existing mutant and RNAi technologies, thereby enabling organismal mechanism of action studies for the natural product clovanemagnolol. Forward chemical genetic screens followed by mechanism of action studies with C. elegans, when coupled with genetic validation of identified targets to reproduce the small molecule's phenotypic effects, provide a unique platform for discovering the biological targets of compounds that affect multicellular processes. First, the use of an immobilized FK506 derivative and soluble competition experiments with optimally prepared soluble C. elegans proteome successfully identified interactions with FK506 binding proteins 1 to 6. This approach was used to determine an unknown mechanism of action for clovanemagnolol, a small molecule that promotes axonal branching in both primary neuronal cultures and in vivo in C. elegans. Following the synthesis of an appropriately functionalized solid-phase reagent bearing a clovanemagnolol analogue pull-down experiments employing soluble competition identified kinesin light chain-1 (KLC-1), a protein involved in axonal cargo transport, as a putative target. This was corroborated through the use of mutant worms lacking klc-1 and possessing GFP neuronal labeling, reproducing the axonal branching phenotype induced by the small molecule clovanemagnolol. PMID:24123757

Zlotkowski, Katherine; Eliasen, Anders M; Mitra, Aurpon; Siegel, Dionicio

2013-11-25

181

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

182

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

183

A gene expression fingerprint of C. elegans embryonic motor neurons  

Microsoft Academic Search

BACKGROUND: Differential gene expression specifies the highly diverse cell types that constitute the nervous system. With its sequenced genome and simple, well-defined neuroanatomy, the nematode C. elegans is a useful model system in which to correlate gene expression with neuron identity. The UNC-4 transcription factor is expressed in thirteen embryonic motor neurons where it specifies axonal morphology and synaptic function.

Rebecca M Fox; Stephen E Von Stetina; Susan J Barlow; Christian Shaffer; Kellen L Olszewski; Jason H Moore; Denis Dupuy; Marc Vidal; David M Miller III

2005-01-01

184

Cell lineage and cell death: Caenorhabditis elegans and cancer research  

Microsoft Academic Search

Cancer is a complex disease in which cells have circumvented normal restraints on tissue growth and have acquired complex abnormalities in their genomes, posing a considerable challenge to identifying the pathways and mechanisms that drive fundamental aspects of the malignant phenotype. Genetic analyses of the normal development of the nematode Caenorhabditis elegans have revealed evolutionarily conserved mechanisms through which individual

Malia B. Potts; Scott Cameron

2010-01-01

185

Genome-wide RNAi analysis of Caenorhabditis elegans  

E-print Network

Red (5H-benzo[a]phenoxazine-5-one, 9-diethylamino)5 to visualize fat storage droplets in living worms pathways controls whether C. elegans larvae grow to fast metabolizing or fat-storing adults7 in the TGF-b pathway SMAD-like protein daf-3 (ref. 7, Fig. 1a and Supplementary Fig. 1). As in mammals

Ahringe, Julie

186

Caenorhabditis elegans glia modulate neuronal activity and behavior  

PubMed Central

Glial cells of Caenorhabditis elegans can modulate neuronal activity and behavior, which is the focus of this review. Initially, we provide an overview of neuroglial evolution, making a comparison between C. elegans glia and their genealogical counterparts. What follows is a brief discussion on C. elegans glia characteristics in terms of their exact numbers, germ layers origin, their necessity for proper development of sensory organs, and lack of their need for neuronal survival. The more specific roles that various glial cells have on neuron-based activity/behavior are succinctly presented. The cephalic sheath glia are important for development, maintenance and activity of central synapses, whereas the amphid glia seem to set the tone of sensory synapses; these glial cell types are ectoderm-derived. Mesoderm-derived Glial-Like cells in the nerve Ring (GLRs) appear to be a part of the circuit for production of motor movement of the worm anterior. Finally, we discuss tools and approaches utilized in studying C. elegans glia, which are assets available for this animal, making it an appealing model, not only in neurosciences, but in biology in general. PMID:24672428

Stout Jr., Randy F.; Verkhratsky, Alexei; Parpura, Vladimir

2014-01-01

187

Dopamine signaling in Caenorhabditis elegans-potential for parkinsonism research.  

PubMed

The nematode Caenorhabditis elegans is an attractive model system for the study of many biological processes. It possesses a simple nervous system with known anatomy and connectivity, is conveniently and cheaply cultured in the laboratory, and is amenable to many genetic manipulations that are impossible in mammalian systems. The recent completion of the C. elegans genome sequence provides a rich resource of genomic and bioinformatic data to researchers in diverse fields. This organism, however, has been underexploited in the studies of many basic processes related to nervous system function, neuropsychiatric disorders and neuromuscular function. Anatomical, biochemical, behavioral, pharmacological and genetic evidence accumulated to date strongly suggests that dopamine is used as a neurotransmitter by C. elegans, and that its effects are mediated through pathway(s) that share many features with those of mammals. DNA sequence analysis reveals genes highly homologous to those encoding mammalian dopamine receptors. Probably, C. elegans has dopamine receptors that transduce environmental cues into behaviors, and these receptors pharmacologically most closely resemble the D2 family. Here we present a review of the current state of research into the dopamine system of the worm, focussing on its potential for use in the study of biological processes related to parkinsonism. PMID:11331184

Wintle, R F.; Van Tol, H H.M.

2001-07-01

188

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

ERIC Educational Resources Information Center

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

Ardiel, Evan L.; Rankin, Catharine H.

2010-01-01

189

Optogenetic manipulation of neural activity in freely moving Caenorhabditis elegans  

Microsoft Academic Search

We present an optogenetic illumination system capable of real-time light delivery with high spatial resolution to specified targets in freely moving Caenorhabditis elegans. A tracking microscope records the motion of an unrestrained worm expressing channelrhodopsin-2 or halorhodopsin in specific cell types. Image processing software analyzes the worm's position in each video frame, rapidly estimates the locations of targeted cells and

Andrew M Leifer; Marc Gershow; Mark J Alkema; Christopher Fang-Yen; Aravinthan D T Samuel

2011-01-01

190

Identification of an estrogenic hormone receptor in Caenorhabditis elegans  

SciTech Connect

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 estrogenic hormone receptors, because they share sequence similarity with the human estrogen receptor. First, the genes were cloned and expressed in Escherichia coli, and then the affinity of each protein for estrogen was determined using a surface plasmon resonance (SPR) biosensor. All three NHRs bound estrogen in a dose-dependent fashion. To evaluate the specificity of the binding, we performed a solution competition assay using an SPR biosensor. According to our results, only NHR-14 was able to interact with estrogen. Therefore, we next examined whether nhr-14 regulates estrogen signaling in vivo. To investigate whether these interactions actually control the response of C. elegans to hormones, we investigated the expression of vitellogenin, an estrogen responsive gene, in an nhr-14 mutant. Semi-quantitative RT-PCR showed that vitellogenin expression was significantly reduced in the mutant. This suggests that NHR-14 is a C. elegans estrogenic hormone receptor and that it controls gene expression in response to estrogen.

Mimoto, Ai; Fujii, Madoka [Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902 (Japan); Usami, Makoto [Division of Pharmacology, National Institute of Health Sciences, Tokyo (Japan); Shimamura, Maki; Hirabayashi, Naoko [Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902 (Japan); Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo (Japan); Kaneko, Takako [Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo (Japan); Sasagawa, Noboru [Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902 (Japan); Ishiura, Shoichi [Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902 (Japan)], E-mail: cishiura@mail.ecc.u-tokyo.ac.jp

2007-12-28

191

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

192

Transgenic C. elegans as a Model in Alzheimer's Research  

Microsoft Academic Search

Alzheimer's disease (AD) has been associated with aggregation of ?-amyloid peptide (A?) and cell death in the brain. Using various models, such as the nematode Caenorhabditis elegans, the fruit fly Drosophila melanogaster and the mouse Mus musculus, investigators have attempted to imitate the pathology process of AD for better understanding of the cellular mechanisms and for possible therapeutic intervention. Among

Yanjue Wu; Yuan Luo

2005-01-01

193

High Genetic Diversity in the Chemoreceptor Superfamily of Caenorhabditis elegans  

PubMed Central

We investigated genetic polymorphism in the Caenorhabditis elegans srh and str chemoreceptor gene families, each of which consists of ?300 genes encoding seven-pass G-protein-coupled receptors. Almost one-third of the genes in each family are annotated as pseudogenes because of apparent functional defects in N2, the sequenced wild-type strain of C. elegans. More than half of these “pseudogenes” have only one apparent defect, usually a stop codon or deletion. We sequenced the defective region for 31 such genes in 22 wild isolates of C. elegans. For 10 of the 31 genes, we found an apparently functional allele in one or more wild isolates, suggesting that these are not pseudogenes but instead functional genes with a defective allele in N2. We suggest the term “flatliner” to describe genes whose functional vs. pseudogene status is unclear. Investigations of flatliner gene positions, dN/dS ratios, and phylogenetic trees indicate that they are not readily distinguished from functional genes in N2. We also report striking heterogeneity in the frequency of other polymorphisms among these genes. Finally, the large majority of polymorphism was found in just two strains from geographically isolated islands, Hawaii and Madeira. This suggests that our sampling of wild diversity in C. elegans is narrow and that identification of additional strains from similarly isolated regions will greatly expand the diversity available for study. PMID:15520260

Stewart, Mary K.; Clark, Nathaniel L.; Merrihew, Gennifer; Galloway, Evan M.; Thomas, James H.

2005-01-01

194

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

195

Allyl isothiocyanate induced stress response in Caenorhabditis elegans  

PubMed Central

Background Allyl isothiocyanate (AITC) from mustard is cytotoxic; however the mechanism of its toxicity is unknown. We examined the effects of AITC on heat shock protein (HSP) 70 expression in Caenorhabditis elegans. We also examined factors affecting the production of AITC from its precursor, sinigrin, a glucosinolate, in ground Brassica juncea cv. Vulcan seed as mustard has some potential as a biopesticide. Findings An assay to determine the concentration of AITC in ground mustard seed was improved to allow the measurement of AITC release in the first minutes after exposure of ground mustard seed to water. Using this assay, we determined that temperatures above 67°C decreased sinigrin conversion to AITC in hydrated ground B. juncea seed. A pH near 6.0 was found to be necessary for AITC release. RT-qPCR revealed no significant change in HSP70A mRNA expression at low concentrations of AITC (< 0.1 ?M). However, treatment with higher concentrations (> 1.0 ?M) resulted in a four- to five-fold increase in expression. A HSP70 ELISA showed that AITC toxicity in C. elegans was ameliorated by the presence of ground seed from low sinigrin B. juncea cv. Arrid. Conclusions • AITC induced toxicity in C. elegans, as measured by HSP70 expression. • Conditions required for the conversion of sinigrin to AITC in ground B. juncea seed were determined. • The use of C. elegans as a bioassay to test AITC or mustard biopesticide efficacy is discussed. PMID:22093285

2011-01-01

196

Silicon-inducible defenses of Zinnia elegans against Myzus persicae  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

197

METABOLISM OF AN INSECT NEUROPEPTIDE BY THE NEMATODE C. ELEGANS  

Technology Transfer Automated Retrieval System (TEKTRAN)

We are interested in neuropeptides in nematodes as leads to new control agents for parasitic nematodes. This includes physiological aspects of neuropeptide action and metabolic regulation of these peptides. The free-living nematode Caenorhabditis elegans, with its mapped genome, offers unique opport...

198

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

199

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

E-print Network

, we have developed detailed simulation models of C. elegans and Drosophila melanogaster (another) is the most investigated of all multi-cellular organisms. Since the proposal to use it as a model organism of this organism. As a result, the com- plete cell lineage, neural circuitry, and various genes and their functions

Luke, Sean

200

Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning  

Microsoft Academic Search

In this report we describe experiments to investigate a simple virulence model in which Pseudomonas aerugi- nosa 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

LARRY A. GALLAGHER; COLIN MANOIL

2001-01-01

201

A Test for Epistasis Among Induced Mutations in Caenorhabditis elegans  

Microsoft Academic Search

Synergistic epistasis, in which deleterious mutations tend to magnify each other's effects, is a necessary component of the mutational deterministic hypothesis for the maintenance of sexual production. We tested for epistasis for life-history traits in the soil nematode Caenorhabditis elegans by inducing mutations in two genetic backgrounds: a wild-type strain and a set of genetically loaded lines that contain large

Andrew D. Peters; Peter D. Keightley

2000-01-01

202

Trehalose metabolism genes in Caenorhabditis elegans and filarial nematodes  

Microsoft Academic Search

The sugar trehalose is claimed to be important in the physiology of nematodes where it may function in sugar transport, energy storage and protection against environmental stresses. In this study we investigated the role of trehalose metabolism in nematodes, using Caenorhabditis elegans as a model, and also identified complementary DNA clones putatively encoding genes involved in trehalose pathways in filarial

F. I Pellerone; S. K Archer; C. A Behm; W. N Grant; M. J Lacey; A. C Somerville

2003-01-01

203

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, University of Massachusetts Medical School, Worcester, MA 01605, USA 2Joslin Diabetes Center, Department the repres- sion of microRNA targets in vivo but do not affect microRNA biogenesis, indicating a role

Blackwell, Keith

204

RESEARCH Open Access Caenorhabditis elegans chromosome arms are  

E-print Network

, suggesting that they are largely looped out from the nuclear membrane. Only the left end of the X chromosomeRESEARCH Open Access Caenorhabditis elegans chromosome arms are anchored to the nuclear membrane determined the genomic regions associated with the nuclear transmembrane protein LEM-2 in mixed- stage C

Lieb, Jason

205

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

206

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

207

SHORT COMMUNICATION Microbeam irradiation of C. elegans nematode in microfluidic  

E-print Network

immobiliza- tion and imaging for irradiation of several whole living samples on a single clamp, here we show To perform high-throughput studies on the biological effects of ionizing radiation in vivo, we have Microbeam irradiation with microfluidic devices Á C. elegans microbeam irradiation Á Small animal microbeam

Brenner, David Jonathan

208

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)

2011-11-21

209

Using Caenorhabditis elegans as a Model for Obesity Pharmacology Development.  

PubMed

The Caenorhabditis elegans model is a rapid and inexpensive method to address pharmacologic questions. We describe the use of C. elegans to explore 2 pharmacologic questions concerning candidate antiobesity drugs and illustrate its potential usefulness in pharmacologic research: (1) to determine a ratio of betahistine-olanzapine that blocks the olanzapine-induced intestinal fat deposition (IFD) as detected by Nile red staining and (2) to identify the mechanism of action of a pharmaceutical candidate AB-101 that reduces IFD. Olanzapine (53 ?g/mL) increased the IFD (12.1 ± 0.1%, P < 0.02), which was blocked by betahistine (763 ?g/mL, 39.3 ± 0.01%, P < 0.05) in wild-type C. elegans (N2). AB-101 (1.0%) reduced the IFD in N2 (P < 0.05), increased the pharyngeal pumping rate (P < 0.05), and reversed the elevated IFD induced by protease inhibitors atazanavir and ritonavir (P < 0.05). AB-101 did not affect IFD in a ACS null mutant strain acs-4(ok2872) III/hT2[bli-4(e937) let-?(q782) qIs48](I;III) suggesting an involvement of the lipid oxidation pathway and an upregulation of CPT-1. Our studies suggest that C. elegans may be used as a resource in pharmacologic research. This article is intended to stimulate a greater appreciation of its value in the development of new pharmaceutical interventions. PMID:24786852

Zheng, Jolene; Vasselli, Joseph R; King, Jason F; King, Michael L; We, Wenqian; Fitzpatrick, Zachary; Johnson, William D; Finley, John W; Martin, Roy J; Keenan, Michael J; Enright, Frederic M; Greenway, Frank L

2014-05-01

210

Quantum dot nanoparticles affect the reproductive system of Caenorhabditis elegans.  

PubMed

Quantum dots (QDs) are an increasingly important class of nanoparticle, but little ecotoxicological data for QDs has been published to date. The effects of mercaptosuccinic acid (MSA)-capped QDs (QDs-MSA) and equivalent concentrations of cadmium (Cd) from cadmium chloride on growth and reproduction of the nematode Caenorhabditis elegans (Rhabditidae) were assessed in laboratory experiments. Growth from larvae to adults of C. elegans was unaffected by exposure to 1?µM fluorescent QDs-MSA, but adults produced more embryos and laid them prematurely. Furthermore, C. elegans exposed to QDs-MSA (1?µM) showed a high percentage of embryo mortality (19.2?±?0.5, p?elegans, but a low incidence of egg-laying defects was observed, suggesting that Cd and QDs-MSA affected C. elegans by different mechanisms. Furthermore, egg-laying defects caused by QDs-MSA responded to the addition of the anticonvulsant ethosuximide and to a lesser extent to the neurotransmitter serotonin, suggesting that QDs-MSA might have disrupted motor neurons during the reproduction process. PMID:22847876

Hsu, Pei-Chun L; O'Callaghan, Maureen; Al-Salim, Najeh; Hurst, Mark R H

2012-10-01

211

Recombinational Landscape and Population Genomics of Caenorhabditis elegans  

PubMed Central

Recombination rate and linkage disequilibrium, the latter a function of population genomic processes, are the critical parameters for mapping by linkage and association, and their patterns in Caenorhabditis elegans are poorly understood. We performed high-density SNP genotyping on a large panel of recombinant inbred advanced intercross lines (RIAILs) of C. elegans to characterize the landscape of recombination and, on a panel of wild strains, to characterize population genomic patterns. We confirmed that C. elegans autosomes exhibit discrete domains of nearly constant recombination rate, and we show, for the first time, that the pattern holds for the X chromosome as well. The terminal domains of each chromosome, spanning about 7% of the genome, exhibit effectively no recombination. The RIAILs exhibit a 5.3-fold expansion of the genetic map. With median marker spacing of 61 kb, they are a powerful resource for mapping quantitative trait loci in C. elegans. Among 125 wild isolates, we identified only 41 distinct haplotypes. The patterns of genotypic similarity suggest that some presumed wild strains are laboratory contaminants. The Hawaiian strain, CB4856, exhibits genetic isolation from the remainder of the global population, whose members exhibit ample evidence of intercrossing and recombining. The population effective recombination rate, estimated from the pattern of linkage disequilibrium, is correlated with the estimated meiotic recombination rate, but its magnitude implies that the effective rate of outcrossing is extremely low, corroborating reports of selection against recombinant genotypes. Despite the low population, effective recombination rate and extensive linkage disequilibrium among chromosomes, which are techniques that account for background levels of genomic similarity, permit association mapping in wild C. elegans strains. PMID:19283065

Rockman, Matthew V.; Kruglyak, Leonid

2009-01-01

212

Identification of the varR Gene as a Transcriptional Regulator of Virginiamycin S Resistance in Streptomyces virginiae  

Microsoft Academic Search

A gene designated varR (for virginiae antibiotic resistance regulator) was identified in Streptomyces virginiae 89 bp downstream of a varS gene encoding a virginiamycin S (VS)-specific transporter. The deduced varR product showed high homology to repressors of the TetR family with a conserved helix-turn-helix DNA binding motif. Purified recombinant VarR protein was present as a dimer in vitro and showed

WISES NAMWAT; CHANG-KWON LEE; HIROSHI KINOSHITA; YASUHIRO YAMADA; TAKUYA NIHIRA

2001-01-01

213

Effects of sterols on the development and aging of Caenorhabditis elegans.  

PubMed

Although Caenorhabditis elegans lacks several components of the de novo sterol biosynthetic pathway, it requires sterols as essential nutrients. Supplemental cholesterol undergoes extensive enzymatic modification in C. elegans to form certain sterols of unknown function. Since sterol metabolism in C. elegans differs from that in other species, such as mammals and yeast, it is important to examine how sterols regulate worm physiology. To examine the functions of sterols in C. elegans, a sterol-feeding experiment was carried out and several critical parameters, such as brood size, growth rate, and life span, were measured. In addition, the change in lipid distribution in C. elegans can be both qualitatively and quantitatively determined by various methods, including staining and chromatographic techniques. Taken together, the effects of sterols on C. elegans are very prominent and can be easily assessed using the techniques described here. PMID:19160668

Lee, Eun-Young; Jeong, Pan-Young; Kim, Sun-Young; Shim, Yhong-Hee; Chitwood, David J; Paik, Young-Ki

2009-01-01

214

[Physiological characteristics of Pinus densiflora var. zhangwuensis and Pinus sylvestris var. mongolica seedlings on sandy lands under salt-alkali stresses].  

PubMed

For the popularization of Pinus densiflora var. zhangwuensis, a new afforestation tree species on the desertified and salinized-alkalized lands in Northern China, and to evaluate the salinity-alkalinity tolerance of the tree species and to better understand the tolerance mechanisms, a pot experiment with 4-year old P. densiflora var. zhangwuensis and P. sylvestris var. mongolica was conducted to study their seedlings growth and physiological and biochemical indices under the effects of three types salt (NaCl, Na2CO3, and NaHCO3 ) stresses and of alkali (NaOH) stress. Under the salt-alkali stresses, the injury level of P. densiflora var. zhangwuensis was lower, and the root tolerance index was higher. The leaf catalase (CAT) activity increased significantly by 22. 6 times at the most, as compared with the control; the leaf malondialdehyde (MDA) content had no significant increase; the leaf chlorophyll (Chl) content had a smaller decrement; and the leaf water content (LWC) increased slightly. P. sylvestris var. mongolica responded differently to the salt-alkali stresses. Its leaf CAT activity had less change, MDA content increased significantly, Chl content had significant decrease, and LWC decreased slightly. It was suggested that P. densi-flora var. zhangwuensis had a greater salinity-alkalinity tolerance than P. sylvestris var. mongolica. The higher iron concentration in P. densiflora var. zhangwuensis needles enhanced the CAT activity and Chl content, whereas the higher concentrations of zinc and copper were associated with the stronger salinity-alkalinity tolerance. PMID:23705379

Meng, Peng; Li, Yu-Ling; Zhang, Bai-xi

2013-02-01

215

[Glycosides from flowers of Jasminum officinale L. var. grandiflorum].  

PubMed

To study the chemical constituents of the flower of Jasminum officinale L. var. grandiflorum. The compounds were isolated and purified by re-crystallization and chromatography on silica gel and Sephadex LH-20 column. Their structures were elucidated on the physicochemical properties and spectral analysis. Seven glycosides were identified as kaempferol-3-O-alpha-L-rhamnopyranosyl (1-->3)-[alpha-L-rhamnopyranosyl (1-->6)]-beta-D-galactopyranoside (I), kaempferol-3-O-rutinoside (II), 7-ketologanin (III), oleoside-11-methyl ester (IV), 7-glucosyl-l1-methyl oleoside (V), ligstroside (VI), oleuropein (VII). Compound I is a new compound. Compounds III and V were isolated from the family of Jasminum for the first time and compounds II, IV and VI were isolated from Jasminum officinale L. var. grandiflorum for the first time. PMID:18229614

Zhao, Gui-qin; Xia, Jing-jing; Dong, Jun-xing

2007-10-01

216

An aberrant variant of Histoplasma capsulatum var. capsulatum.  

PubMed Central

We studied an aberrant culture of Histoplasma capsulatum var. capsulatum isolated from synovial fluid collected from the right elbow of a patient from Kansas. Colonies on Sabouraud glucose agar and other routine mycological media were glabrous to soft, moist, heaped, deeply folded or convoluted, and orange-brown with a white, irregular margin. Microscopically, hyphae were hyaline, septate, and branched and remained totally devoid of conidiation over a period of 2 years on all mycological media. Conversion to the yeast form was achieved on Pine's medium at 37 degrees C. Colonies at early stages of growth were smooth, moist, pasty, shiny, and orange-brown but soon became wrinkled and slightly raised and produced oval, thin-walled cells measuring 2 to 3 by to 4.5 microns which multiplied by polar budding. The identity of the isolate was further confirmed by utilizing the Accuprobe DNA and the exoantigen test for H. capsulatum var. capsulatum. PMID:9041422

Sutton, D A; Padhye, A A; Standard, P G; Rinaldi, M G

1997-01-01

217

A new phenylpropanoid glycosides from Paris polyphylla var. yunnanensis.  

PubMed

A new phenylpropanoid glycosides, 2-feruloyl-O-alpha-D-glucopyranoyl-(1'-->2)-3,6-O-feruloyl-beta-D-fructofuranoside, was isolated from the root of Paris polyphylla var. yunnanensis. The structure of the new glycoside was elucidated by spectroscopic methods. Cytotoxicity test showed that it has cytotoxic effect in a dose-dependent manner against the mice lung adenocarcinoma cell line (LA795). PMID:18353566

Yan, Lulu; Gao, Wenyuan; Zhang, Yanjun; Wang, Yu

2008-06-01

218

Two new compounds from Trifolium resupinatum var. microcephalum.  

PubMed

An investigation of CH(2)Cl(2) and EtOH extracts of Trifolium resupinatum L. var. microcephalum Zoh. has led to the isolation of two new compounds characterized as 4,15-dimethyl-2-(1,2-dihydroxyethyl)-hexadecene (1) and 1-undecene-1-O-beta-2',3',4',6'-tetraacetyl glucopyranoside (2a). Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy. PMID:19031240

Sabudak, Temine; Isik, Emel; Oksuz, Sevil

2008-01-01

219

Two new compounds from Trifolium resupinatum var. microcephalum  

Microsoft Academic Search

An investigation of CH2Cl2 and EtOH extracts of Trifolium resupinatum L. var. microcephalum Zoh. has led to the isolation of two new compounds characterized as 4,15-dimethyl-2-(1,2-dihydroxyethyl)-hexadecene (1) and 1-undecene-1-O-?-2?,3?,4?,6?-tetraacetyl glucopyranoside (2a). Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy.

Temine Sabudak; Emel Isik; Sevil Oksuz

2008-01-01

220

The Caenorhabditis elegans Gene mfap-1 Encodes a Nuclear Protein That Affects Alternative Splicing  

E-print Network

factor genes uaf-1 (the C. elegans U2AF large subunit gene) and sfa-1 (the C. elegans SF1/BBP gene). WeRNP complex and the SF1/U2AF65/U2AF35 protein complex recognize the 59 and 39 splice sites of an intronThe Caenorhabditis elegans Gene mfap-1 Encodes a Nuclear Protein That Affects Alternative Splicing

Horvitz, H. Robert

221

The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14  

Microsoft Academic Search

Summary h-4 is essential for the normal temporal control of diverse postembryonic developmental events in C. elegans. \\/in-4 acts by negatively regulating the level of LIN-14 protein, creating a temporal decrease in LIN-14 protein starting in the first larval stage (Ll). We have cloned the C. elegans lin-4 locus by chromosomal walking and transformation rescue. We used the C. elegans

Rosalind C. Lee; Rhonda L. Feinbaum; Victor Ambros

1993-01-01

222

Wnt and EGF pathways act together to induce C. elegans male hook development  

E-print Network

Comparative studies of vulva development between Caenorhabditis elegans and other nematode species have provided some insight into the evolution of patterning networks. However, molecular genetic details are available ...

Sternberg, Paul W.

223

[Effects of fungal elicitors on the secondary metabolite steroidal saponin in Paris polyphylla var. yunnanensis].  

PubMed

To compare the effects of inoculated or non-inoculated with arbuscular mycorrhizal (AM) fungi on the steroidal saponin component in root of Paris polyphylla var. yunnanensis. By pot experiments, steroid saponin component in root of P. polyphylla var. yunnanensis was determined and compared by HPLC. The results showed there was difference in the effects of different AM fungal on the secondary metabolite steroid saponin in P. polyphylla var. yunnanensis. After elicitors treatment, AM fungal did not change the chemical backgrounds of P. polyphylla var. yunnanensis, but can improve partly the content of chemical compositions in roots. In conclusion, there was selectivity between AM fungal and P. polyphylla var. yunnanensis. Glomus intraradices was the most appropriate strain for inoculation P. polyphylla var. yunnanensis. PMID:23227557

Zhou, Nong; Zhang, De-Quan; Sun, Qin; Jiang, Bei; Huang, Zhi-Chao

2012-09-01

224

Caenorhabditis elegans as a simple model to study phenotypic and genetic virulence determinants of extraintestinal pathogenic Escherichia coli strains  

E-print Network

of extraintestinal pathogenic Escherichia coli strains Caenorhabditis elegans as a simple model to study phenotypic and genotypic determinants of pathogenicity of extraintestinal pathogenic Escherichia coli Virulence of extraintestinal pathogenic Escherichia coli strains in Caenorhabditis elegans Virulence of extraintestinal

Paris-Sud XI, Université de

225

Corticosterone and pace of life in two life-history ecotypes of the garter snake Thamnophis elegans  

E-print Network

Corticosterone and pace of life in two life-history ecotypes of the garter snake Thamnophis elegans of the garter snake (Thamnophis elegans) that exhibit slow and fast pace of life strategies. We subjected free

Bronikowski, Anne

226

Metabolism, Body Size and Life Span: A Case Study in Evolutionarily Divergent Populations of the Garter Snake (Thamnophis elegans)  

E-print Network

of the Garter Snake (Thamnophis elegans) Anne Bronikowski1 and David Vleck Ecology, Evolution and Organismal of metabolism, life history and aging in the western terrestrial garter snake (Thamnophis elegans). Early

Bronikowski, Anne

227

Fat synthesis and adiposity regulation in Caenorhabditis elegans  

PubMed Central

Understanding the regulation of fat synthesis and the consequences of its misregulation is of profound significance for managing the obesity epidemic and developing obesity therapeutics. Recent work in the roundworm Caenorhabditis elegans has revealed the importance of evolutionarily conserved pathways of fat synthesis and nutrient sensing in adiposity regulation. The powerful combination of mutational and reverse genetic analysis, genomics, lipid analysis, and cell-specific expression studies enables dissection of complicated pathways at the level of a whole organism. This review summarizes recent studies in C. elegans that offer insights into the regulation of adiposity by conserved transcription factors, insulin and growth factor signaling, and unsaturated fatty acid synthesis. Increased understanding of fat-storage pathways might lead to future obesity therapies. PMID:19181539

Watts, Jennifer L.

2009-01-01

228

A microfluidic device for efficient chemical testing using Caenorhabditis elegans.  

PubMed

The nematode worm Caenorhabditis elegans has been employed as a popular model organism in many fields of biological research. In this paper, we present a microfluidic device for facilitating chemical testing using C. elegans. For testing chemicals on chip, the device houses single nematodes in microfluidic chambers and precisely adjusts the chamber's chemical environment during experiments. Eight nematodes can be readily loaded into the chambers through separate loading channels in a quick and gentle manner. In addition, a custom-made software with a graphic user interface is also created for quantitative analysis of locomotion parameters (swimming frequency and bend amplitude) of the nematodes in response to chemical stimuli, thus greatly enhancing the efficiency of data collection. We perform proof-of-concept experiments using two chemicals, zinc ion (Zn(2+)) and glucose, to demonstrate the effectiveness of the microfluidic device. PMID:25744157

Song, Pengfei; Zhang, Weize; Sobolevski, Alexandre; Bernard, Kristine; Hekimi, Siegfried; Liu, Xinyu

2015-04-01

229

Direct measurements of drag forces in C. elegans crawling locomotion.  

PubMed

With a simple and versatile microcantilever-based force measurement technique, we have probed the drag forces involved in Caenorhabditis elegans locomotion. As a worm crawls on an agar surface, we found that substrate viscoelasticity introduces nonlinearities in the force-velocity relationships, yielding nonconstant drag coefficients that are not captured by original resistive force theory. A major contributing factor to these nonlinearities is the formation of a shallow groove on the agar surface. We measured both the adhesion forces that cause the worm's body to settle into the agar and the resulting dynamics of groove formation. Furthermore, we quantified the locomotive forces produced by C. elegans undulatory motions on a wet viscoelastic agar surface. We show that an extension of resistive force theory is able to use the dynamics of a nematode's body shape along with the measured drag coefficients to predict the forces generated by a crawling nematode. PMID:25418179

Rabets, Yegor; Backholm, Matilda; Dalnoki-Veress, Kari; Ryu, William S

2014-10-21

230

Transcriptional regulation of gene expression in C. elegans.  

PubMed

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 proteins 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

231

Genome-Wide RNAi Longevity Screens in Caenorhabditis elegans  

PubMed Central

Progress in aging research has identified genetic and environmental factors that regulate longevity across species. The nematode worm Caenorhabditis elegans is a genetically tractable model system that has been widely used to investigate the molecular mechanisms of aging, and the development of RNA interference (RNAi) technology has provided a powerful tool for performing large-scale genetic screens in this organism. Genome-wide screens have identified hundreds of genes that influence lifespan, many of which fall into distinct functional classes and pathways. The purpose of this review is to summarize the results of large-scale RNAi longevity screens in C. elegans, and to provide an in-depth comparison and analysis of their methodology and most significant findings. PMID:23633911

Yanos, Melana E; Bennett, Christopher F; Kaeberlein, Matt

2012-01-01

232

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

González-Aguilera, Cristina; Palladino, Francesca

2014-01-01

233

Integrated control of protein degradation in C. elegans muscle  

PubMed Central

Protein degradation is a fundamental cellular process, the genomic control of which is incompletely understood. The advent of transgene-coded reporter proteins has enabled the development of C. elegans into a model for studying this problem. The regulation of muscle protein degradation is surprisingly complex, integrating multiple signals from hypodermis, intestine, neurons and muscle itself. Within the muscle, degradation is executed by separately regulated autophagy-lysosomal, ubiquitin-proteasome and calpain-mediated systems. The signal-transduction mechanisms, in some instances, involve modules previously identified for their roles in developmental processes, repurposed in terminally differentiated muscle to regulate the activities of pre-formed proteins. Here we review the genes, and mechanisms, which appear to coordinately control protein degradation within C. elegans muscle. We also consider these mechanisms in the context of development, physiology, pathophysiology and disease models. PMID:23457662

Lehmann, Susann; Shephard, Freya; Jacobson, Lewis A.; Szewczyk, Nathaniel J.

2012-01-01

234

Mechanical Cues in the Early Embryogenesis of Caenorhabditis elegans  

PubMed Central

Biochemical signaling pathways in developmental processes have been extensively studied, yet the role of mechanical cues during embryogenesis is much less explored. Here we have used selective plane illumination microscopy in combination with a simple mechanical model to quantify and rationalize cell motion during early embryogenesis of the small nematode Caenorhabditis elegans. As a result, we find that cell organization in the embryo until gastrulation is well described by a purely mechanical model that predicts cells to assume positions in which they face the least repulsive interactions from other cells and the embryo’s egg shell. Our findings therefore suggest that mechanical interactions are key for a rapid and robust cellular arrangement during early embryogenesis of C. elegans. PMID:24138856

Fickentscher, Rolf; Struntz, Philipp; Weiss, Matthias

2013-01-01

235

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

236

Dynamics of C. elegans in various fluidic environments  

NASA Astrophysics Data System (ADS)

C. elegans is a freely moving soil nematode that crawls or swims by propagating a body wave backwards. In fluids we investigate its swimming locomotion as the fluid viscosity is varied over many orders of magnitude and in the presence of non-Newtonian fluid responses. For Newtonian fluids we find power-law relations between swimming speed and fluid viscosity, and these relations are not in accordance with assumptions of constant power input to the fluid. We also find that the Strouhal frequency is nearly independent of viscosity and swimming speed. We investigate the influence of confinement on C. elegans locomotion and find that interactions between confining walls and body undulations can markedly increase swimming speed.

Jung, Sunghwan; Kim, Erica; Piano, Fabio; Zhang, Jun; Shelley, Michael

2006-11-01

237

Noncanonical cell death in the nematode Caenorhabditis elegans  

PubMed Central

The nematode Caenorhabditis. elegans has served as a fruitful setting for cell death research for over three decades. A conserved pathway of four genes, egl-1/BH3-only, ced-9/Bcl-2, ced-4/Apaf-1, and ced-3/caspase, coordinates most developmental cell deaths in C. elegans. However, other cell death forms, programmed and pathological, have also been described in this animal. Some of these share morphological and/or molecular similarities with the canonical apoptotic pathway, while others do not. Indeed, recent studies suggest the existence of an entirely novel mode of programmed developmental cell destruction that may also be conserved beyond nematodes. Here we review evidence for these noncanonical pathways. We propose that different cell death modalities can function as backup mechanisms for apoptosis, or as tailor-made programs that allow specific dying cells to be efficiently cleared from the animal. PMID:25065890

Kinet, Maxime J.; Shaham, Shai

2014-01-01

238

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

239

Aging. Lysosomal signaling molecules regulate longevity in Caenorhabditis elegans.  

PubMed

Lysosomes are crucial cellular organelles for human health that function in digestion and recycling of extracellular and intracellular macromolecules. We describe a signaling role for lysosomes that affects aging. In the worm Caenorhabditis elegans, the lysosomal acid lipase LIPL-4 triggered nuclear translocalization of a lysosomal lipid chaperone LBP-8, which promoted longevity by activating the nuclear hormone receptors NHR-49 and NHR-80. We used high-throughput metabolomic analysis to identify several lipids in which abundance was increased in worms constitutively overexpressing LIPL-4. Among them, oleoylethanolamide directly bound to LBP-8 and NHR-80 proteins, activated transcription of target genes of NHR-49 and NHR-80, and promoted longevity in C. elegans. These findings reveal a lysosome-to-nucleus signaling pathway that promotes longevity and suggest a function of lysosomes as signaling organelles in metazoans. PMID:25554789

Folick, Andrew; Oakley, Holly D; Yu, Yong; Armstrong, Eric H; Kumari, Manju; Sanor, Lucas; Moore, David D; Ortlund, Eric A; Zechner, Rudolf; Wang, Meng C

2015-01-01

240

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

241

Antisense long noncoding RNAs regulate var gene activation in the malaria parasite Plasmodium falciparum  

PubMed Central

The virulence of Plasmodium falciparum, the causative agent of the deadliest form of human malaria, is attributed to its ability to evade human immunity through antigenic variation. These parasites alternate between expression of variable antigens, encoded by members of a multicopy gene family named var. Immune evasion through antigenic variation depends on tight regulation of var gene expression, ensuring that only a single var gene is expressed at a time while the rest of the family is maintained transcriptionally silent. Understanding how a single gene is chosen for activation is critical for understanding mutually exclusive expression but remains a mystery. Here, we show that antisense long noncoding RNAs (lncRNAs) initiating from var introns are associated with the single active var gene at the time in the cell cycle when the single var upstream promoter is active. We demonstrate that these antisense transcripts are incorporated into chromatin, and that expression of these antisense lncRNAs in trans triggers activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules down-regulated the active var gene, erased the epigenetic memory, and induced expression switching. Altogether, our data provide evidence that these antisense lncRNAs play a key role in regulating var gene activation and mutually exclusive expression. PMID:25691743

Amit-Avraham, Inbar; Pozner, Guy; Eshar, Shiri; Fastman, Yair; Kolevzon, Netanel; Yavin, Eylon; Dzikowski, Ron

2015-01-01

242

Antisense long noncoding RNAs regulate var gene activation in the malaria parasite Plasmodium falciparum.  

PubMed

The virulence of Plasmodium falciparum, the causative agent of the deadliest form of human malaria, is attributed to its ability to evade human immunity through antigenic variation. These parasites alternate between expression of variable antigens, encoded by members of a multicopy gene family named var. Immune evasion through antigenic variation depends on tight regulation of var gene expression, ensuring that only a single var gene is expressed at a time while the rest of the family is maintained transcriptionally silent. Understanding how a single gene is chosen for activation is critical for understanding mutually exclusive expression but remains a mystery. Here, we show that antisense long noncoding RNAs (lncRNAs) initiating from var introns are associated with the single active var gene at the time in the cell cycle when the single var upstream promoter is active. We demonstrate that these antisense transcripts are incorporated into chromatin, and that expression of these antisense lncRNAs in trans triggers activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules down-regulated the active var gene, erased the epigenetic memory, and induced expression switching. Altogether, our data provide evidence that these antisense lncRNAs play a key role in regulating var gene activation and mutually exclusive expression. PMID:25691743

Amit-Avraham, Inbar; Pozner, Guy; Eshar, Shiri; Fastman, Yair; Kolevzon, Netanel; Yavin, Eylon; Dzikowski, Ron

2015-03-01

243

Improving the Caenorhabditis elegans Genome Annotation Using Machine Learning  

PubMed Central

For modern biology, precise genome annotations are of prime importance, as they allow the accurate definition of genic regions. We employ state-of-the-art machine learning methods to assay and improve the accuracy of the genome annotation of the nematode Caenorhabditis elegans. The proposed machine learning system is trained to recognize exons and introns on the unspliced mRNA, utilizing recent advances in support vector machines and label sequence learning. In 87% (coding and untranslated regions) and 95% (coding regions only) of all genes tested in several out-of-sample evaluations, our method correctly identified all exons and introns. Notably, only 37% and 50%, respectively, of the presently unconfirmed genes in the C. elegans genome annotation agree with our predictions, thus we hypothesize that a sizable fraction of those genes are not correctly annotated. A retrospective evaluation of the Wormbase WS120 annotation [1] of C. elegans reveals that splice form predictions on unconfirmed genes in WS120 are inaccurate in about 18% of the considered cases, while our predictions deviate from the truth only in 10%–13%. We experimentally analyzed 20 controversial genes on which our system and the annotation disagree, confirming the superiority of our predictions. While our method correctly predicted 75% of those cases, the standard annotation was never completely correct. The accuracy of our system is further corroborated by a comparison with two other recently proposed systems that can be used for splice form prediction: SNAP and ExonHunter. We conclude that the genome annotation of C. elegans and other organisms can be greatly enhanced using modern machine learning technology. PMID:17319737

Rätsch, Gunnar; Sonnenburg, Sören; Srinivasan, Jagan; Witte, Hanh; Müller, Klaus-R; Sommer, Ralf-J; Schölkopf, Bernhard

2007-01-01

244

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

245

Caenorhabditis elegans neuromuscular junction: GABA receptors and ivermectin action.  

PubMed

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

246

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

247

Phagocytosis promotes programmed cell death in C. elegans  

Microsoft Academic Search

In the nematode Caenorhabditis elegans programmed cell death requires the killer genes egl-1, ced-4 and ced-3 (refs 1 and 2), and the engulfment of dying cells requires the genes ced-1, ced-2, ced-5, ced-6, ced-7, ced-10 and ced-12 (refs 3,4,5). Here we show that engulfment promotes programmed cell death. Mutations that cause partial loss of function of killer genes allow the

Peter W. Reddien; Scott Cameron; H. Robert Horvitz

2001-01-01

248

C. Elegans as a Disease Model for Neuroacanthocytosis  

Microsoft Academic Search

The core machinery responsible for the execution of the apoptotic program is conserved from invertebrates to humans [14,26,27].\\u000a The Caenorhabditis elegans ced-8 gene was identified in a screen for mutants defective in cell death (ced) [4]. Loss of CED-8 function results in delayed appearance and removal of cell corpses. Mutations in ced-8 weakly protect from apoptotic cell death and enhance

Kelvin Wong; Michael Hengartner

249

Fate of the Nuclear Lamina during Caenorhabditis elegans Apoptosis  

Microsoft Academic Search

Invertebrates and in Drosophila, lamins and lamin-associated proteins are primary targets for cleavage by caspases. Eliminating mammalian lamins causes apoptosis, whereas expressing mutant lamins that cannot be cleaved by caspase-6 delay apoptosis. Caenorhabditis elegans has a single lamin protein, Ce-lamin, and a caspase, CED-3, that is responsible for most if not all somatic apoptosis. In this study we show that

Yonatan B. Tzur; Bradley M. Hersh; H. Robert Horvitz; Yosef Gruenbaum

2002-01-01

250

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

251

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

252

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

253

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

254

A transcribed polyketide synthase gene from Xanthoria elegans  

Microsoft Academic Search

We characterize the transcript of a polyketide synthase gene (PKS) from the cultured mycobiont of Xanthoria elegans (XePKS1) using SMART-rapid amplification of cDNA ends (RACE) cDNA synthesis. Sequence analysis of the cloned cDNA reveals an open reading frame of 2144 amino acid residues. It contains features of a non-reducing fungal type I PKS with an N-terminal starter unit: acyl carrier protein

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

2009-01-01

255

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

256

Biotransformation of fluorene by the fungus Cunninghamella elegans  

SciTech Connect

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

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

1993-06-01

257

Neurotoxic effects of TDP-43 overexpression in C. elegans  

PubMed Central

RNA-binding protein TDP-43 has been associated with multiple neurodegenerative diseases, including amyotrophic lateral sclerosis and frontotemporal lobar dementia. We have engineered pan-neuronal expression of human TDP-43 protein in Caenorhabditis elegans, with the goal of generating a convenient in vivo model of TDP-43 function and neurotoxicity. Transgenic worms with the neuronal expression of human TDP-43 exhibit an ‘uncoordinated’ phenotype and have abnormal motorneuron synapses. Caenorhabditis elegans contains a single putative ortholog of TDP-43, designated TDP-1, which we show can support alternative splicing of CFTR in a cell-based assay. Neuronal overexpression of TDP-1 also results in an uncoordinated phenotype, while genetic deletion of the tdp-1 gene does not affect movement or alter motorneuron synapses. By using the uncoordinated phenotype as a read-out of TDP-43 overexpression neurotoxicty, we have investigated the contribution of specific TDP-43 domains and subcellular localization to toxicity. Full-length (wild-type) human TDP-43 expressed in C. elegans is localized to the nucleus. Deletion of either RNA recognition domain (RRM1 or RRM2) completely blocks neurotoxicity, as does deletion of the C-terminal region. These deleted TDP-43 variants still accumulate in the nucleus, although their subnuclear distribution is altered. Interestingly, fusion of TDP-1 C-terminal sequences to TDP-43 missing its C-terminal domain restores normal subnuclear localization and toxicity in C. elegans and CFTR splicing in cell-based assays. Overexpression of wild-type, full-length TDP-43 in mammalian cells (differentiated M17 cells) can also result in cell toxicity. Our results demonstrate that in vivo TDP-43 neurotoxicity can result from nuclear activity of overexpressed full-length protein. PMID:20530643

Ash, Peter E.A.; Zhang, Yong-Jie; Roberts, Christine M.; Saldi, Tassa; Hutter, Harald; Buratti, Emanuele; Petrucelli, Leonard; Link, Christopher D.

2010-01-01

258

Genomic analysis of stress response against arsenic in Caenorhabditis elegans.  

PubMed

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

259

Phospholipase C-? Regulates Epidermal Morphogenesis in Caenorhabditis elegans  

Microsoft Academic Search

Migration of cells within epithelial sheets is an important feature of embryogenesis and other biological processes. Previous work has demonstrated a role for inositol 1,4,5-trisphosphate (IP3)-mediated calcium signalling in the rearrangement of epidermal cells (also known as hypodermal cells) during embryonic morphogenesis in Caenorhabditis elegans. However the mechanism by which IP3 production is stimulated is unknown. IP3 is produced by

Rafael P. Vázquez-Manrique; Anikó I. Nagy; James C. Legg; Olivia A. M. Bales; Sung Ly; Howard A. Baylis

2008-01-01

260

Tomosyn Inhibits Synaptic Vesicle Priming in Caenorhabditis elegans  

E-print Network

Tomosyn Inhibits Synaptic Vesicle Priming in Caenorhabditis elegans Elena O. Gracheva1, Anna O. Burdina1, Andrea M. Holgado2, Martine Berthelot-Grosjean1, Brian D. Ackley1, Gayla Hadwiger3, Michael L. Nonet3, Robby M. Weimer4, Janet E. Richmond1* 1... Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America, 2 Biology Department, Loyola University Chicago, Chicago, Illinois, United States of America, 3 Department of Anatomy and Neurobiology...

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

261

Mating Damages the Cuticle of C. elegans Hermaphrodites  

PubMed Central

Lifespan costs to reproduction are common across multiple species, and such costs could potentially arise through a number of mechanisms. In the nematode Caenorhabditis elegans, it has been suggested that part of the lifespan cost to hermaphrodites from mating results from physical damage owing to the act of copulation itself. Here, we examine whether mating damages the surface of the hermaphrodite cuticle via scanning electron microscopy. It is found that mated hermaphrodites suffered delamination of cuticle layers surrounding the vulva, and that the incidence of such damage depends on genetic background. Unmated hermaphrodites demonstrated almost no such damage, even when cultured in soil with potentially abrasive particles. Thus, a consequence of mating for C. elegans hermaphrodites is physical cuticle damage. These experiments did not assess the consequences of cuticle damage for lifespan, and the biological significance of this damage remains unclear. We further discuss our results within the context of recent studies linking the lifespan cost to mating in C. elegans hermaphrodites to male secretions. PMID:25105881

Woodruff, Gavin C.; Knauss, Christine M.; Maugel, Timothy K.; Haag, Eric S.

2014-01-01

262

Specioside ameliorates oxidative stress and promotes longevity in Caenorhabditis elegans.  

PubMed

Specioside (6-O-coumaroylcatalpol) is an iridoid glucoside which possesses multifunctional activities viz. analgesic, antidyspeptic, astringent, liver stimulating and wound healing properties. The present study for the first time delineates stress alleviating and lifespan prolonging action of specioside (SPC), isolated from Stereospermum suaveolens in the free living, multicellular nematode model Caenorhabditis elegans. A strong correlation between lifespan extension and stress modulation in adult worms was established in a dose dependent manner. The dietary intake of this phytomolecule elevated juglone induced oxidative and heat induced thermal stress tolerance in C. elegans. On evaluation, it was found that 25?M dose of SPC significantly extended lifespan by 15.47% (P?0.0001) with reduction in stress level. Furthermore, SPC enhanced mean survival in mev-1 mutant suggesting its oxidative stress reducing potential. Furthermore, SPC augmented stress modulatory enzymes superoxide dismutase (SOD) and catalase (CAT) level in C. elegans. Altogether, these findings broaden current perspectives concerning stress alleviating potentials of SPC and have implications in development of therapeutics for curing age related disorders. PMID:25619942

Asthana, Jyotsna; Yadav, A K; Pant, Aakanksha; Pandey, Swapnil; Gupta, M M; Pandey, Rakesh

2015-03-01

263

Exposure to Mitochondrial Genotoxins and Dopaminergic Neurodegeneration in Caenorhabditis elegans  

PubMed Central

Neurodegeneration has been correlated with mitochondrial DNA (mtDNA) damage and exposure to environmental toxins, but causation is unclear. We investigated the ability of several known environmental genotoxins and neurotoxins to cause mtDNA damage, mtDNA depletion, and neurodegeneration in Caenorhabditis elegans. We found that paraquat, cadmium chloride and aflatoxin B1 caused more mitochondrial than nuclear DNA damage, and paraquat and aflatoxin B1 also caused dopaminergic neurodegeneration. 6-hydroxydopamine (6-OHDA) caused similar levels of mitochondrial and nuclear DNA damage. To further test whether the neurodegeneration could be attributed to the observed mtDNA damage, C. elegans were exposed to repeated low-dose ultraviolet C radiation (UVC) that resulted in persistent mtDNA damage; this exposure also resulted in dopaminergic neurodegeneration. Damage to GABAergic neurons and pharyngeal muscle cells was not detected. We also found that fasting at the first larval stage was protective in dopaminergic neurons against 6-OHDA-induced neurodegeneration. Finally, we found that dopaminergic neurons in C. elegans are capable of regeneration after laser surgery. Our findings are consistent with a causal role for mitochondrial DNA damage in neurodegeneration, but also support non mtDNA-mediated mechanisms. PMID:25486066

Bodhicharla, Rakesh K.; McKeever, Madeline G.; Arrant, Andrew E.; Margillo, Kathleen M.; Ryde, Ian T.; Cyr, Derek D.; Kosmaczewski, Sara G.; Hammarlund, Marc; Meyer, Joel N.

2014-01-01

264

Deubiquitylation machinery is required for embryonic polarity in Caenorhabditis elegans.  

PubMed

The Caenorhabditis elegans one-cell embryo polarizes in response to a cue from the paternally donated centrosome and asymmetrically segregates cell fate determinants that direct the developmental program of the worm. We have found that genes encoding putative deubiquitylating enzymes (DUBs) are required for polarization of one-cell embryos. Maternal loss of the proteins MATH-33 and USP-47 leads to variable inability to correctly establish and maintain asymmetry as defined by posterior and anterior polarity proteins PAR-2 and PAR-3. The first observable defect is variable positioning of the centrosome with respect to the cell cortex and the male pronucleus. The severity of the polarity defects correlates with distance of the centrosome from the cortex. Furthermore, polarity defects can be bypassed by mutations that bring the centrosome in close proximity to the cortex. In addition we find that polarity and centrosome positioning defects can be suppressed by compromising protein turnover. We propose that the DUB activity of MATH-33 and USP-47 stabilizes one or more proteins required for association of the centrosome with the cortex. Because these DUBs are homologous to two members of a group of DUBs that act in fission yeast polarity, we tested additional members of that family and found that another C. elegans DUB gene, usp-46, also contributes to polarity. Our finding that deubiquitylating enzymes required for polarity in Schizosaccharomyces pombe are also required in C. elegans raises the possibility that these DUBs act through an evolutionarily conserved mechanism to control cell polarity. PMID:23209443

McCloskey, Richard J; Kemphues, Kenneth J

2012-01-01

265

hecd-1 Modulates Notch Activity in Caenorhabditis elegans  

PubMed Central

Notch is a receptor that mediates cell–cell interactions that specify binary cell fate decisions in development and tissue homeostasis. Inappropriate Notch signaling is associated with cancer, and mutations in Notch pathway components have been associated with developmental diseases and syndromes. In Caenorhabditis elegans, suppressors of phenotypes associated with constitutively active LIN-12/Notch have identified many conserved core components and direct or indirect modulators. Here, we molecularly identify sel(ar584), originally isolated as a suppressor of a constitutively active allele of lin-12. We show that sel(ar584) is an allele of hecd-1, the ortholog of human HECDT1, a ubiquitin ligase that has been implicated in several different mammalian developmental events. We studied interactions of hecd-1 with lin-12 in the somatic gonad and with the other C. elegans Notch gene, glp-1, in the germ line. We found that hecd-1 acts as a positive modulator of lin-12/Notch activity in a somatic gonad context—the original basis for its isolation—but acts autonomously as a negative modulator of glp-1/Notch activity in the germ line. As the yeast ortholog of HECD-1, Ufd4p, has been shown to function in quality control, and C. elegans HECD-1 has been shown to affect mitochondrial maintenance, we propose that the different genetic interactions between hecd-1 and Notch genes we observed in different cell contexts may reflect differences in quality control regulatory mechanisms or in cellular metabolism. PMID:25552605

Chen, Yunting; Greenwald, Iva

2014-01-01

266

Control of Oocyte Growth and Meiotic Maturation in C. elegans  

PubMed Central

In sexually reproducing animals, oocytes arrest at diplotene or diakinesis and resume meiosis (meiotic maturation) in response to hormones. Chromosome segregation errors in female meiosis I are the leading cause of human birth defects, and age-related changes in the hormonal environment of the ovary are a suggested cause. C. elegans is emerging as a genetic paradigm for studying hormonal control of meiotic maturation. The meiotic maturation processes in C. elegans and mammals share a number of biological and molecular similarities. Major sperm protein (MSP) and luteinizing hormone (LH), though unrelated in sequence, both trigger meiotic resumption using somatic G?s-adenylate cyclase pathways and soma-germline gap-junctional communication. At a molecular level, the oocyte responses apparently involve the control of conserved protein kinase pathways and post-transcriptional gene regulation in the oocyte. At a cellular level, the responses include cortical cytoskeletal rearrangement, nuclear envelope breakdown, assembly of the acentriolar meiotic spindle, chromosome segregation, and likely changes important for fertilization and the oocyte-to-embryo transition. This chapter focuses on signaling mechanisms required for oocyte growth and meiotic maturation in C. elegans and discusses how these mechanisms coordinate the completion of meiosis and the oocyte-to-embryo transition. PMID:22872481

Kim, Seongseop; Spike, Caroline; Greenstein, David

2013-01-01

267

Mechanistic analysis of the search behaviour of Caenorhabditis elegans  

PubMed Central

A central question in movement research is how animals use information and movement to promote encounter success. Current random search theory identifies reorientation patterns as key to the compromise between optimizing encounters for both nearby and faraway targets, but how the balance between intrinsic motor programmes and previous environmental experience determines the occurrence of these reorientation behaviours remains unknown. We used high-resolution tracking and imaging data to describe the complete motor behaviour of Caenorhabditis elegans when placed in a novel environment (one in which food is absent). Movement in C. elegans is structured around different reorientation behaviours, and we measured how these contributed to changing search strategies as worms became familiar with their new environment. This behavioural transition shows that different reorientation behaviours are governed by two processes: (i) an environmentally informed ‘extrinsic’ strategy that is influenced by recent experience and that controls for area-restricted search behaviour, and (ii) a time-independent, ‘intrinsic’ strategy that reduces spatial oversampling and improves random encounter success. Our results show how movement strategies arise from a balance between intrinsic and extrinsic mechanisms, that search behaviour in C. elegans is initially determined by expectations developed from previous environmental experiences, and which reorientation behaviours are modified as information is acquired from new environments. PMID:24430127

Salvador, Liliana C. M.; Bartumeus, Frederic; Levin, Simon A.; Ryu, William S.

2014-01-01

268

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

269

In vivo Neuronal Calcium Imaging in C. elegans  

PubMed Central

The nematode worm C. elegans is an ideal model organism for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, well-characterized nervous system allows identification and fluorescence imaging of any neuron within the intact animal. Simple immobilization techniques with minimal impact on the animal's physiology allow extended time-lapse imaging. The development of genetically-encoded calcium sensitive fluorophores such as cameleon 1 and GCaMP 2 allow in vivo imaging of neuronal calcium relating both cell physiology and neuronal activity. Numerous transgenic strains expressing these fluorophores in specific neurons are readily available or can be constructed using well-established techniques. Here, we describe detailed procedures for measuring calcium dynamics within a single neuron in vivo using both GCaMP and cameleon. We discuss advantages and disadvantages of both as well as various methods of sample preparation (animal immobilization) and image analysis. Finally, we present results from two experiments: 1) Using GCaMP to measure the sensory response of a specific neuron to an external electrical field and 2) Using cameleon to measure the physiological calcium response of a neuron to traumatic laser damage. Calcium imaging techniques such as these are used extensively in C. elegans and have been extended to measurements in freely moving animals, multiple neurons simultaneously and comparison across genetic backgrounds. C. elegans presents a robust and flexible system for in vivo neuronal imaging with advantages over other model systems in technical simplicity and cost. PMID:23603812

Gabel, Christopher V.

2013-01-01

270

Black tea increased survival of Caenorhabditis elegans under stress.  

PubMed

The present study examined the effects of black tea (Camellia sinensis) extracts (BTE) in Caenorhabditis elegans under various abiotic stressors. Results showed BTE increased nematode resistance to osmosis, heat, and UV irradiation treatments. However, BTE could not increase nematodes' lifespan under normal culture conditions and MnCl2-induced toxicity at concentrations we used. Further studies showed that BTE decreased reactive oxygen species and up-regulated some antioxidant enzymes, including GSH-PX, and genes, such as gsh-px and sod-3. However, only a slight extension in mev-1 mutants mean lifespan was observed without significance. These results indicated that the antioxidant activity of BTE might be necessary but not sufficient to protect against aging to C. elegans. Moreover, BTE increased the mRNA level of stress-response genes such as sir-2.1 and sek-1. Our finding demonstrated BTE might increase heat and UV stress resistance in a sir.2.1-dependent manner. Taken together, BTE enhanced stress resistance with multiple mechanisms in C. elegans. PMID:25345740

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

2014-11-19

271

RNAi screening to identify postembryonic phenotypes in C. elegans.  

PubMed

C. elegans has proven to be a valuable model system for the discovery and functional characterization of many genes and gene pathways. More sophisticated tools and resources for studies in this system are facilitating continued discovery of genes with more subtle phenotypes or roles. Here we present a generalized protocol we adapted for identifying C. elegans genes with postembryonic phenotypes of interest using RNAi. This procedure is easily modified to assay the phenotype of choice, whether by light or fluorescence optics on a dissecting or compound microscope. This screening protocol capitalizes on the physical assets of the organism and molecular tools the C. elegans research community has produced. As an example, we demonstrate the use of an integrated transgene that expresses a fluorescent product in an RNAi screen to identify genes required for the normal localization of this product in late stage larvae and adults. First, we used a commercially available genomic RNAi library with full-length cDNA inserts. This library facilitates the rapid identification of multiple candidates by RNAi reduction of the candidate gene product. Second, we generated an integrated transgene that expresses our fluorecently tagged protein of interest in an RNAi-sensitive background. Third, by exposing hatched animals to RNAi, this screen permits identification of gene products that have a vital embryonic role that would otherwise mask a post-embryonic role in regulating the protein of interest. Lastly, this screen uses a compound microscope equipped for single cell resolution. PMID:22353760

Beifuss, Katherine K; Gumienny, Tina L

2012-01-01

272

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

273

Cell-specific proteomic analysis in Caenorhabditis elegans.  

PubMed

Proteomic analysis of rare cells in heterogeneous environments presents difficult challenges. Systematic methods are needed to enrich, identify, and quantify proteins expressed in specific cells in complex biological systems including multicellular plants and animals. Here, we have engineered a Caenorhabditis elegans phenylalanyl-tRNA synthetase capable of tagging proteins with the reactive noncanonical amino acid p-azido-l-phenylalanine. We achieved spatiotemporal selectivity in the labeling of C. elegans proteins by controlling expression of the mutant synthetase using cell-selective (body wall muscles, intestinal epithelial cells, neurons, and pharyngeal muscle) or state-selective (heat-shock) promoters in several transgenic lines. Tagged proteins are distinguished from the rest of the protein pool through bioorthogonal conjugation of the azide side chain to probes that permit visualization and isolation of labeled proteins. By coupling our methodology with stable-isotope labeling of amino acids in cell culture (SILAC), we successfully profiled proteins expressed in pharyngeal muscle cells, and in the process, identified proteins not previously known to be expressed in these cells. Our results show that tagging proteins with spatiotemporal selectivity can be achieved in C. elegans and illustrate a convenient and effective approach for unbiased discovery of proteins expressed in targeted subsets of cells. PMID:25691744

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

2015-03-01

274

Aluminium exposure disrupts elemental homeostasis in Caenorhabditis elegans  

PubMed Central

Aluminium (Al) is highly abundant in the environment and can elicit a variety of toxic responses in biological systems. Here we characterize the effects of Al on Caenorhabditis elegans by identifying phenotypic abnormalities and disruption in whole-body metal homeostasis (metallostasis) following Al exposure in food. Widespread changes to the elemental content of adult nematodes were observed when chronically exposed to Al from the first larval stage (L1). Specifically, we saw increased barium, chromium, copper and iron content, and a reduction in calcium levels. Lifespan was decreased in worms exposed to low levels of Al, but unexpectedly increased when the Al concentration reached higher levels (4.8 mM). This bi-phasic phenotype was only observed when Al exposure occurred during development, as lifespan was unaffected by Al exposure during adulthood. Lower levels of Al slowed C. elegans developmental progression, and reduced hermaphrodite self-fertility and adult body size. Significant developmental delay was observed even when Al exposure was restricted to embryogenesis. Similar changes in Al have been noted in association with Al toxicity in humans and other mammals, suggesting that C. elegans may be of use as a model for understanding the mechanisms of Al toxicity in mammalian systems. PMID:22534883

Page, Kathryn E.; White, Keith N.; McCrohan, Catherine R.

2013-01-01

275

Deubiquitylation Machinery Is Required for Embryonic Polarity in Caenorhabditis elegans  

PubMed Central

The Caenorhabditis elegans one-cell embryo polarizes in response to a cue from the paternally donated centrosome and asymmetrically segregates cell fate determinants that direct the developmental program of the worm. We have found that genes encoding putative deubiquitylating enzymes (DUBs) are required for polarization of one-cell embryos. Maternal loss of the proteins MATH-33 and USP-47 leads to variable inability to correctly establish and maintain asymmetry as defined by posterior and anterior polarity proteins PAR-2 and PAR-3. The first observable defect is variable positioning of the centrosome with respect to the cell cortex and the male pronucleus. The severity of the polarity defects correlates with distance of the centrosome from the cortex. Furthermore, polarity defects can be bypassed by mutations that bring the centrosome in close proximity to the cortex. In addition we find that polarity and centrosome positioning defects can be suppressed by compromising protein turnover. We propose that the DUB activity of MATH-33 and USP-47 stabilizes one or more proteins required for association of the centrosome with the cortex. Because these DUBs are homologous to two members of a group of DUBs that act in fission yeast polarity, we tested additional members of that family and found that another C. elegans DUB gene, usp-46, also contributes to polarity. Our finding that deubiquitylating enzymes required for polarity in Schizosaccharomyces pombe are also required in C. elegans raises the possibility that these DUBs act through an evolutionarily conserved mechanism to control cell polarity. PMID:23209443

McCloskey, Richard J.; Kemphues, Kenneth J.

2012-01-01

276

Undulatory Locomotion of Caenorhabditis elegans on Wet Surfaces  

PubMed Central

The physical and biomechanical principles that govern undulatory movement on wet surfaces have important applications in physiology, physics, and engineering. The nematode Caenorhabditis elegans, with its highly stereotypical and functionally distinct sinusoidal locomotory gaits, is an excellent system in which to dissect these properties. Measurements of the main forces governing the C. elegans crawling gait on lubricated surfaces have been scarce, primarily due to difficulties in estimating the physical features at the nematode-gel interface. Using kinematic data and a hydrodynamic model based on lubrication theory, we calculate both the surface drag forces and the nematode's bending force while crawling on the surface of agar gels within a preexisting groove. We find that the normal and tangential surface drag coefficients during crawling are ?222 and 22, respectively, and the drag coefficient ratio is ?10. During crawling, the calculated internal bending force is time-periodic and spatially complex, exhibiting a phase lag with respect to the nematode's body bending curvature. This phase lag is largely due to viscous drag forces, which are higher during crawling as compared to swimming in an aqueous buffer solution. The spatial patterns of bending force generated during either swimming or crawling correlate well with previously described gait-specific features of calcium signals in muscle. Further, our analysis indicates that one may be able to control the motility gait of C. elegans by judiciously adjusting the magnitude of the surface drag coefficients. PMID:22735527

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

2012-01-01

277

Methods to Assess Subcellular Compartments of Muscle in C. elegans  

PubMed Central

Muscle is a dynamic tissue that responds to changes in nutrition, exercise, and disease state. The loss of muscle mass and function with disease and age are significant public health burdens. We currently understand little about the genetic regulation of muscle health with disease or age. The nematode C. elegans is an established model for understanding the genomic regulation of biological processes of interest. This worm’s body wall muscles display a large degree of homology with the muscles of higher metazoan species. Since C. elegans is a transparent organism, the localization of GFP to mitochondria and sarcomeres allows visualization of these structures in vivo. Similarly, feeding animals cationic dyes, which accumulate based on the existence of a mitochondrial membrane potential, allows the assessment of mitochondrial function in vivo. These methods, as well as assessment of muscle protein homeostasis, are combined with assessment of whole animal muscle function, in the form of movement assays, to allow correlation of sub-cellular defects with functional measures of muscle performance. Thus, C. elegans provides a powerful platform with which to assess the impact of mutations, gene knockdown, and/or chemical compounds upon muscle structure and function. Lastly, as GFP, cationic dyes, and movement assays are assessed non-invasively, prospective studies of muscle structure and function can be conducted across the whole life course and this at present cannot be easily investigated in vivo in any other organism. PMID:25489753

Gaffney, Christopher J.; Bass, Joseph J.; Barratt, Thomas F.; Szewczyk, Nathaniel J.

2014-01-01

278

From the Cover: Restriction of vaccinia virus replication by a ced-3 and ced-4-dependent pathway in Caenorhabditis elegans  

Microsoft Academic Search

Genetic tractability and easy manipulation make Caenorhabditis elegans a good model to study host-pathogen interactions. Dozens of different bacterial species can pathogenically infect C. elegans under laboratory conditions, and all of these microbes are extracellular pathogens to nematodes. Viruses, on the other hand, are obligate intracellular parasites, and yet no viral infections have been reported for C. elegans. We established

Wan-Hsin Liu; Yi-Ling Lin; Jia-Pey Wang; Willisa Liou; Roger F. Hou; Yi-Chun Wu; Ching-Len Liao

2006-01-01

279

The cat-1 Gene of Caenorhabditis elegans Encodes a Vesicular Monoamine Transporter Required for Specific Monoamine Dependent Behaviors  

Microsoft Academic Search

We have identified the Caenorhabditis elegans homolog of the mammalian vesicular monoamine transporters (VMATs); it is 47% identical to human VMAT1 and 49% identical to human VMAT2. C. elegans VMAT is associated with synaptic vesicles in ;25 neurons, including all of the cells reported to contain dopamine and serotonin, plus a few others. When C. elegans VMAT is expressed in

Janet S. Duerr; Dennis L. Frisby; Jennifer Gaskin; Angie Duke; Karen Asermely; David Huddleston; Lee E. Eiden; James B. Rand

1999-01-01

280

Changes in Nuclear Receptor and Vitellogenin Gene Expression in Response to Steroids and Heavy Metal in Caenorhabditis elegans  

Microsoft Academic Search

SYNOPSIS. To gain basic understanding of the reproductive and developmental effects of endocrine dis- rupting chemicals in invertebrates, we have used C. elegans as an animal model. The completion of the C. elegans genome sequence brings to bear microarray analysis as a tool for these studies. We previously showed that the C. elegans genome was responsive to vertebrate steroid hormones,

APOLONIA NOVILLO; S EUNG-JAE WON; IAN P. C ALLARD

2005-01-01

281

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.

282

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

283

NRL Release Number 06-1226-1945 PROC partition(VAR f:[int->nat], L:int, H:int, VAR P:int)  

E-print Network

:[int->nat], L:int, H:int, VAR P:int) f_save: [int->nat] = f; P_save: int = P; VAR lo, hi: int; VAR v: nat; L0: SKIP; L1: lo := L; L2: hi := H; L3: v := f(lo); L4: WHILE (hi > lo) DO L5: WHILE (f(hi) >= v & hi > lo) DO L6: hi := hi - 1; L7: ENDWHILE; L8: IF (hi > lo) THEN L9: f := f WITH [(lo) := f(hi), (hi) := v

284

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

285

Topological Cluster Analysis Reveals the Systemic Organization of the Caenorhabditis elegans Connectome  

Microsoft Academic Search

The modular organization of networks of individual neurons interwoven through synapses has not been fully explored due to the incredible complexity of the connectivity architecture. Here we use the modularity-based community detection method for directed, weighted networks to examine hierarchically organized modules in the complete wiring diagram (connectome) of Caenorhabditis elegans (C. elegans) and to investigate their topological properties. Incorporating

Yunkyu Sohn; Myung-Kyu Choi; Yong-Yeol Ahn; Junho Lee; Jaeseung Jeong

2011-01-01

286

ELEVATED CHOLESTEROL LEVEL IN A CAENORHABDITIS ELEGANS LINE IS CORRELATED WITH INCREASED LONGEVITY AND STRESS RESISTANCE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Like all nematodes, Caenorhabditis elegans possesses a nutritional requirement for sterol because of lack of several enzymes in the de novo sterol biosynthesis pathway. Similar to most plant-parasitic nematodes, C. elegans converts plant sterols to cholesterol. Unlike phytoparasitic nematodes, C. ...

287

Improved gene targeting in C. elegans using counter-selection and Flp-mediated marker excision  

Microsoft Academic Search

Gene targeting is widely used for the precise manipulation of genes. However, in the model organism Caenorhabditis elegans non-transposon mediated gene targeting remains laborious, and as a result has not been widely used. One obstacle to the wider use of this approach is the difficulty of identifying homologous recombination events amongst non-specific events. To improve gene targeting in C. elegans,

Rafael P. Vázquez-Manrique; James C. Legg; Birgitta Olofsson; Sung Ly; Howard A. Baylis

2010-01-01

288

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

E-print Network

death in C. elegans. Powerful molecular and genetic techniques such as germline transformation (71 Programmed cell death in C. elegans: the genetic framework Ding Xue1 , Yi-Chun Wu2 , and Manisha) 492-7744 #12;2 1. Introduction Programmed cell death is an important cellular process that controls

Xue, Ding

289

C. elegans ATAD-3 is essential for mitochondrial activity and development  

Microsoft Academic Search

BACKGROUND: Mammalian ATAD3 is a mitochondrial protein, which is thought to play an important role in nucleoid organization. However, its exact function is still unresolved. RESULTS: Here, we characterize the Caenorhabditis elegans (C. elegans) ATAD3 homologue (ATAD-3) and investigate its importance for mitochondrial function and development. We show that ATAD-3 is highly conserved among different species and RNA mediated interference

Michael Hoffmann; Nadège Bellance; Rodrigue Rossignol; Werner J. H. Koopman; Peter H. G. M. Willems; Ertan Mayatepek; Olaf Bossinger; Felix Distelmaier

2009-01-01

290

Sexual reproduction in solitary corals: Overlapping oogenic and brooding cycles, and benthic planulas in Balanophyllia elegans  

Microsoft Academic Search

The temperate solitary coral Balanophyllia elegans Verrill, 1864 was collected monthly between January 1977 and August 1978 off the California coast. B. elegans reproduces only sexually, is gonochoric, and broods its embryos. Males are ripe only in late summer, but oocytes and embryos (ca. 40 per female) are found throughout the year. The presence of oocytes and embryos throughout the

Y. H. Fadlallah; J. S. Pearse

1982-01-01

291

DRP1-mediated mitochondrial fragmentation during EGL-1-induced cell death in C. elegans  

Microsoft Academic Search

Genetic analyses in Caenorhabditis elegans have been instrumental in the elucidation of the central cell-death machinery, which is conserved from C. elegans to mammals. One possible difference that has emerged is the role of mitochondria. By releasing cytochrome c, mitochondria are involved in the activation of caspases in mammals. However, there has previously been no evidence that mitochondria are involved

Ravi Jagasia; Phillip Grote; Benedikt Westermann; Barbara Conradt

2005-01-01

292

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

293

Inhibition of CED3 zymogen activation and apoptosis in Caenorhabditis elegans by caspase homolog CSP3  

Microsoft Academic Search

Inhibitor of apoptosis (IAP) proteins have a crucial role in apoptosis, through negative regulation of caspases in species from fruitflies to mammals. In Caenorhabditis elegans, however, no IAP homolog or caspase inhibitor has been identified, calling into question how the cell-killing caspase CED-3 can be negatively regulated. Here we show that inactivation of the C. elegans csp-3 gene, which encodes

Xin Geng; Yong Shi; Akihisa Nakagawa; Sawako Yoshina; Shohei Mitani; Yigong Shi; Ding Xue

2008-01-01

294

Genetic Control of Sex Differences in C. elegans Neurobiology and Behavior  

Microsoft Academic Search

As a well?characterized, genetically tractable animal, the nematode Caenorhabditis elegans is an ideal model to explore the connections between genes and the sexual regulation of the nervous system and behavior. The two sexes of C. elegans, males and hermaphrodites, have precisely defined differences in neuroanatomy: superimposed onto a “core” nervous system of exactly 294 neurons, hermaphrodites and males have 8

Douglas S. Portman

2007-01-01

295

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

296

Two Genetic Circuits Repress the Caenorhabditis elegans Heterochronic Gene lin-28  

E-print Network

gene lin-4 encodes a 22-nt RNA that acts in the first larval stage (L1) to repress two otherTwo Genetic Circuits Repress the Caenorhabditis elegans Heterochronic Gene lin-28 after Translation, Philadelphia, Pennsylvania 19111 The heterochronic gene lin-28 of the nematode Caenorhabditis elegans controls

Moss, Eric G.

297

Brief Communication 1543 Caenorhabditis elegans is a model host for Salmonella  

E-print Network

reserved. Results and discussion Under normal laboratory conditions, C. elegans feeds on Escherichia coli on E. coli expressing GFP (OP50­GFP), bacteria were also found in the intestine after just 2 days (12023 ssaV­GFP [10]) and is as virulent as the wild type as regards the killing of C. elegans. In C

Ewbank, Jonathan

298

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

299

Mating and Dauer Pheromones from Caenorhabditis elegans National High Magnetic Field Laboratory  

E-print Network

Mating and Dauer Pheromones from Caenorhabditis elegans National High Magnetic Field Laboratory) of one of the pheromones (lower left). Previous studies utilized over 300 L to identify the first dauer pheromone. #12;C. elegans is one of the best-studied model organisms. Important discoveries using this small

Weston, Ken

300

Selenite Enhances Immune Response against Pseudomonas aeruginosa PA14 via SKN-1 in Caenorhabditis elegans  

PubMed Central

Background Selenium (Se) is an important nutrient that carries out many biological processes including maintaining optimal immune function. Here, inorganic selenite (Se(IV)) was evaluated for its pathogen resistance and potential-associated factors in Caenorhabditis elegans. The immune effects of Se(IV) were investigated by examining the responses of C. elegans to Pseudomonas aerugonisa PA14 strain. Principal Findings Se(IV)-treated C. elegans showed increased survival under PA14 infection compared with untreated controls. The significant pathogen resistance of Se(IV) on C. elegans might not be attributed to the effects of Se(IV) on PA14 as Se(IV) showed no effect on bacterial quorum-sensing and virulence factors of PA14. This study showed that Se(IV) enhanced the expression of a gene pivotal for the innate immunity in C. elegans. The study found that the pathogen-resistant phenotypes contributed by Se(IV) was absent from the skn-1 mutant worms. Moreover, Se(IV) influenced the subcellular distribution of SKN-1/Nrf in C. elegans upon PA14 infection. Furthermore, Se(IV) increased mRNA levels of SKN-1 target genes (gst-4 and gcs-1). Conclusions This study found evidence of Se(IV) protecting C. elegans against P. aeruginosa PA14 infection by exerting effects on the innate immunity of C. elegans that is likely mediated via regulation of a SKN-1-dependent signaling pathway. PMID:25147937

Huang, Chi-Wei; Wei, Chia-Cheng; Liao, Vivian Hsiu-Chuan

2014-01-01

301

Nucleosome DNA Bendability Matrix (C. elegans) http://www.jbsdonline.com  

E-print Network

). In this work we describe full reconstruction of the 10.4 base repeat of nucleosome DNA of C. elegans fromNucleosome DNA Bendability Matrix (C. elegans) http://www.jbsdonline.com Abstract An original signal extraction procedure is applied to database of 146 base nucleosome core DNA sequences from C

Barash, Danny

302

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

303

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

304

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

305

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

306

A Chemosensory Adaptation Module for the Physiology Laboratory from Student-Directed "C. elegans" Research  

ERIC Educational Resources Information Center

The model organism, "Caenorhabditis elegans," in addition to being well suited to genetics and cell biology teaching applications, can also be useful in the physiology laboratory. In this article, the author describes how students in a junior level college Comparative Physiology course have made use of "C. elegans" in semester-long,…

Lindblom, Tim

2006-01-01

307

A diacylglycerol kinase modulates long-term thermotactic behavioral plasticity in C. elegans  

Microsoft Academic Search

A memory of prior thermal experience governs Caenorhabditis elegans thermotactic behavior. On a spatial thermal gradient, C. elegans tracks isotherms near a remembered temperature we call the thermotactic set-point (TS). The TS corresponds to the previous cultivation temperature and can be reset by sustained exposure to a new temperature. The mechanisms underlying this behavioral plasticity are unknown, partly because sensory

David Biron; Mayumi Shibuya; Christopher Gabel; Sara M Wasserman; Damon A Clark; Adam Brown; Piali Sengupta; Aravinthan D T Samuel

2006-01-01

308

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

309

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

310

Identification of two epoxide hydrolases in Caenorhabditis elegans that metabolize mammalian lipid signaling molecules  

E-print Network

for Caenorhabditis elegans that code for proteins with significant sequence similarity to the mammalian soluble epoxide hydrolase (sEH). The respective transcripts were cloned from a mixed stage cDNA library from C. elegans. The corresponding proteins obtained after recombinant expression in insect cells hydrolyzed

Hammock, Bruce D.

311

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

E-print Network

of the condensin homolog DPY-27 and the zinc finger protein SDC-3, two components of the C. elegans dosageX chromosome repression by localization of the C. elegans dosage compensation machinery to sites for tuning DCC activity at specific loci. These data aid in understanding how proteins involved in higher

Lieb, Jason

312

C. elegans dosage compensation: A window into mechanisms of domain-scale gene regulation  

E-print Network

C. elegans dosage compensation: A window into mechanisms of domain-scale gene regulation Sevinc Abstract The C. elegans dosage compensation com- plex (DCC) reduces transcript levels from each of the two hermaphrodite X chromosomes to equalize X- linked gene expression to that of XO males. Several of the proteins

Lieb, Jason

313

Metabolic pathway profiling of mitochondrial respiratory chain mutants in C. elegans  

Microsoft Academic Search

Caenorhabditis elegans affords a model of primary mitochondrial dysfunction that provides insight into cellular adaptations which accompany mutations in nuclear genes that encode mitochondrial proteins. To this end, we characterized genome-wide expression profiles of C. elegans strains with mutations in nuclear-encoded subunits of respiratory chain complexes. Our goal was to detect concordant changes among clusters of genes that comprise defined

M. J. Falk; Z. Zhang; J. R. Rosenjack; I. Nissim; E. Daikhin; M. M. Sedensky; M. Yudkoff; P. G. Morgan

2008-01-01

314

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

E-print Network

of age-related phenotypic changes that correlate with lifespan in C. elegans. Introduction Certain, but does not prevent worms from performing normal swimming motions. Second, the adjoining worm clamps. Longitudinal measurements are useful in the study of aging, which in C. elegans involves a number of phenotypic

Prentiss, Mara

315

Nature Macmillan Publishers Ltd 1998 gate C. elegans genes. Comparison with pre-  

E-print Network

the course of the Human Genome Project, pushing it from a mapping mode to a sequencing mode. Second, the C. elegans project has been a model for how an efficient genome effort can be run. As far as I know rather than a researcher-orientated strategy. Third, the C. elegans Genome Project has stimulated

Koehl, Mimi

316

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

317

Caenorhabditis elegans aristaless/Arx gene alr-1 restricts variable gene expression  

E-print Network

Caenorhabditis elegans aristaless/Arx gene alr-1 restricts variable gene expression Irini- derstood. For example, mutations in the gene encoding the transcription factor ALR-1 in Caenorhabditis elegans result in vari- able touch receptor neuron (TRN) function. Using single-molecule in situ

van Oudenaarden, Alexander

318

Phenolic acids in the flowers of Althaea rosea var. nigra.  

PubMed

Distribution of phenolic acids in the flowers of Althaea rosea var. nigra has been studied by 2D-TLC and HPLC methods. The phenolic acids occurring in these fractions have been identified as ferulic, vanillic, syringic, p-coumaric, p-hydroxybenzoic, p-hydroxyphenylacetic and caffeic acids. By means of the HPLC methods the contents of major phenolic acids were estimated. From among the phenolic acids analyzed the syringic, p-hydroxybenzoic and p-coumaric acids are dominant. Total content of phenolic acids was determined by the Arnov's method. PMID:20085226

Dudek, Marlena; Mat?awska, Irena; Szkudlarek, Maurycy

2006-01-01

319

Sesquiterpenes and other constituents from Dendranthema zawadskii var. latilobum.  

PubMed

Six new germacranolides, zawadskinolides A-F (1-6), and a new eudesmane glucoside, chrysantiloboside (7) were isolated from the aerial parts of Dendranthema zawadskii var. latilobum, along with thirteen known constituents. Their structures were elucidated by means of spectroscopic evidence. Bioassay showed that flavonoids such as apigenin (9), (-)-eriodictyol (10) and nepetin (12), as well as the sesquiterpene lactone, zawadskinolide F (6), inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells with IC50 values of 66.15, 132.55, 35.44, and 91.32??M, respectively. PMID:22382409

Shin, Hyun Jung; Lee, So Young; Kim, Ju Sun; Lee, Sanghyun; Choi, Ran Joo; Chung, Ha Sook; Kim, Yeong Shik; Kang, Sam Sik

2012-01-01

320

Insight into the family of Na+/Ca2+ exchangers of Caenorhabditis elegans.  

PubMed

Here we provide the first genome-wide in vivo analysis of the Na+/Ca2+ exchanger family in the model system Caenorhabditis elegans. We source all members of this family within the Caenorhabditis genus and reconstruct their phylogeny across humans and Drosophila melanogaster. Next, we provide a description of the expression pattern for each exchanger gene in C. elegans, revealing a wide expression in a number of tissues and cell types including sensory neurons, interneurons, motor neurons, muscle cells, and intestinal tissue. Finally, we conduct a series of behavioral and functional analyses through mutant characterization in C. elegans. From these data we demonstrate that, similar to mammalian systems, the expression of Na+/Ca2+ exchangers in C. elegans is skewed toward excitable cells, and we propose that C. elegans may be an ideal model system for the study of Na+/Ca2+ exchangers. PMID:23893482

Sharma, Vishal; He, Chao; Sacca-Schaeffer, Julian; Brzozowski, Eric; Martin-Herranz, Daniel E; Mendelowitz, Zelda; Fitzpatrick, David A; O'Halloran, Damien M

2013-10-01

321

Insight into the Family of Na+/Ca2+ Exchangers of Caenorhabditis elegans  

PubMed Central

Here we provide the first genome-wide in vivo analysis of the Na+/Ca2+ exchanger family in the model system Caenorhabditis elegans. We source all members of this family within the Caenorhabditis genus and reconstruct their phylogeny across humans and Drosophila melanogaster. Next, we provide a description of the expression pattern for each exchanger gene in C. elegans, revealing a wide expression in a number of tissues and cell types including sensory neurons, interneurons, motor neurons, muscle cells, and intestinal tissue. Finally, we conduct a series of behavioral and functional analyses through mutant characterization in C. elegans. From these data we demonstrate that, similar to mammalian systems, the expression of Na+/Ca2+ exchangers in C. elegans is skewed toward excitable cells, and we propose that C. elegans may be an ideal model system for the study of Na+/Ca2+ exchangers. PMID:23893482

Sharma, Vishal; He, Chao; Sacca-Schaeffer, Julian; Brzozowski, Eric; Martin-Herranz, Daniel E.; Mendelowitz, Zelda; Fitzpatrick, David A.; O’Halloran, Damien M.

2013-01-01

322

Generation of Antigenic Diversity in Plasmodium falciparum by Structured Rearrangement of Var Genes During Mitosis  

PubMed Central

The most polymorphic gene family in P. falciparum is the ?60 var genes distributed across parasite chromosomes, both in the subtelomeres and in internal regions. They encode hypervariable surface proteins known as P. falciparum erythrocyte membrane protein 1 (PfEMP1) that are critical for pathogenesis and immune evasion in Plasmodium falciparum. How var gene sequence diversity is generated is not currently completely understood. To address this, we constructed large clone trees and performed whole genome sequence analysis to study the generation of novel var gene sequences in asexually replicating parasites. While single nucleotide polymorphisms (SNPs) were scattered across the genome, structural variants (deletions, duplications, translocations) were focused in and around var genes, with considerable variation in frequency between strains. Analysis of more than 100 recombination events involving var exon 1 revealed that the average nucleotide sequence identity of two recombining exons was only 63% (range: 52.7–72.4%) yet the crossovers were error-free and occurred in such a way that the resulting sequence was in frame and domain architecture was preserved. Var exon 1, which encodes the immunologically exposed part of the protein, recombined in up to 0.2% of infected erythrocytes in vitro per life cycle. The high rate of var exon 1 recombination indicates that millions of new antigenic structures could potentially be generated each day in a single infected individual. We propose a model whereby var gene sequence polymorphism is mainly generated during the asexual part of the life cycle. PMID:25521112

Kekre, Mihir; Otto, Thomas D.; Faizullabhoy, Adnan; Rayner, Julian C.; Kwiatkowski, Dominic

2014-01-01

323

Evidence that the Human Pathogenic Fungus Cryptococcus neoformans var. grubii May Have Evolved in Africa  

Microsoft Academic Search

Most of the species of fungi that cause disease in mammals, including Cryptococcus neoformans var. grubii (serotype A), are exogenous and non-contagious. Cryptococcus neoformans var. grubii is associated worldwide with avian and arboreal habitats. This airborne, opportunistic pathogen is profoundly neurotropic and the leading cause of fungal meningitis. Patients with HIV\\/AIDS have been ravaged by cryptococcosis – an estimated one

Anastasia P. Litvintseva; Ignazio Carbone; Jenny Rossouw; Rameshwari Thakur; Nelesh P. Govender; Thomas G. Mitchell; Kirsten Nielsen

2011-01-01

324

Amlioration des plantes Obtention chez l'chalote (Allium cepa L var  

E-print Network

in shallot (Allium cepa L var aggregatum). Embryos of gynogenetic origin have been obtained by in vitro culture of flower buds from many shallot genotypes on basal B5 medium of Gamborg with high sucrose haploids in shallot breeding can now be proposed. Allium cepa L var aggregatum = shallot / gynogenesis

Paris-Sud XI, Université de

325

Spiral phyllotaxis of needle fascicles on branches and scales on cones in Pinus contorta var.  

E-print Network

Spiral phyllotaxis of needle fascicles on branches and scales on cones in Pinus contorta var-grain spiral in seedlings, young, and mature trees of Rocky Moun- tain lodgepole pine (Pinus contorta Dougl. ex, Pinus contorta var. latifolia, phyllotaxis, generative spiral, Fibonacci numbers, spiral wood grain

Coxson, Darwyn

326

Characterization of 12 polymorphic microsatellite loci of pityopsis graminifolia var. latifolia  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pityopsis graminifolia (Michx.) Small var. latifolia (Fern.) Semple is an herbaceous perennial that grows in close proximity to the federally endangered species P. ruthii (Small) Small. Twelve polymorphic microsatellite loci were identified from 87 samples of P. graminifolia var. latifolia and addit...

327

The Impact of External Shocks in East Asia: Lessons from a Structural VAR Model  

E-print Network

The Impact of External Shocks in East Asia: Lessons from a Structural VAR Model with BlockXhttp://economix.fr UMR 7235 #12;1 The Impact ofExternal Shocks in East Asia: Lessonsfrom a Structural VAR Model examine the relative importance of external shocks in domestic fluctuations of East Asian countries

Paris-Sud XI, Université de

328

Wealth Effects and Consumption: A Panel VAR Approach Xin Shen, Mark J. Holmes and Steven Lim  

E-print Network

1 Wealth Effects and Consumption: A Panel VAR Approach Xin Shen, Mark J. Holmes and Steven Lim between stock market wealth effect and housing wealth effect on consumption. Using a panel VAR approach applied to OECD data, we find evidence that stock market wealth effect is larger than `net housing wealth

329

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

330

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

331

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

332

Empirical analysis on future-cash arbitrage risk with portfolio VaR  

NASA Astrophysics Data System (ADS)

This paper constructs the positive arbitrage position by alternating the spot index with Chinese Exchange Traded Fund (ETF) portfolio and estimating the arbitrage-free interval of futures with the latest trade data. Then, an improved Delta-normal method was used, which replaces the simple linear correlation coefficient with tail dependence correlation coefficient, to measure VaR (Value-at-risk) of the arbitrage position. Analysis of VaR implies that the risk of future-cash arbitrage is less than that of investing completely in either futures or spot market. Then according to the compositional VaR and the marginal VaR, we should increase the futures position and decrease the spot position appropriately to minimize the VaR, which can minimize risk subject to certain revenues.

Chen, Rongda; Li, Cong; Wang, Weijin; Wang, Ze

2014-03-01

333

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.

334

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

335

Caenorhabditis elegans-based Model Systems for Antifungal Drug Discovery  

PubMed Central

The substantial morbidity and mortality associated with invasive fungal infections constitute undisputed tokens of their severity. The continued expansion of susceptible population groups (such as immunocompromised individuals, patients undergoing extensive surgery, and those hospitalized with serious underlying diseases especially in the intensive care unit) and the limitations of current antifungal agents due to toxicity issues or to the development of resistance, mandate the development of novel antifungal drugs. Currently, drug discovery is transitioning from the traditional in vitro large-scale screens of chemical libraries to more complex bioassays, including in vivo studies on whole animals; invertebrates, such as Caenorhabditis elegans, are thus gaining momentum as screening tools. Key pathogenesis features of fungal infections, including filament formation, are expressed in certain invertebrate and mammalian hosts; among the various potential hosts, C. elegans provides an attractive platform both for the study of host-pathogen interactions and the identification of new antifungal agents. Advantages of compound screening in this facile, relatively inexpensive and not as ethically challenged whole-animal context, include the simultaneous assessment of antifungal efficacy and toxicity that could result in the identification of compounds with distinct mechanisms of action, for example by promoting host immune responses or by impeding fungal virulence factors. With the recent advent of using predictive models to screen for compounds with improved chances of bioavailability in the nematode a priori, high-throughput screening of chemical libraries using the C. elegans-c. albicans antifungal discovery assay holds even greater promise for the identification of novel antifungal agents in the near future. PMID:21470110

Anastassopoulou, Cleo G.; Fuchs, Beth Burgwyn; Mylonakis, Eleftherios

2013-01-01

336

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

337

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

338

C. elegans: a model of Fanconi anemia and ICL repair.  

PubMed

Fanconi anemia (FA) is a severe recessive disorder with a wide range of clinical manifestations [M. Levitus, H. Joenje, J.P. de Winter, The Fanconi anemia pathway of genomic maintenance, Cell Oncol. 28 (2006) 3-29]. In humans, 13 complementation groups have been identified to underlie FA: A, B, C, D1, D2, E, F, G, I, J, L, M, and N [W. Wang, Emergence of a DNA-damage response network consisting of Fanconi anaemia and BRCA proteins, Nat. Rev. Genet. 8 (2007) 735-748]. Cells defective for any of these genes display chromosomal aberrations and sensitivity to DNA interstrand cross-links (ICLs). It has therefore been suggested that the 13 FA proteins constitute a pathway for the repair of ICLs, and that a deficiency in this repair process causes genomic instability leading to the different clinical phenotypes. However, the exact nature of this repair pathway, or even whether all 13 FA proteins are involved at some stage of a linear repair process, remains to be defined. Undoubtedly, the recent identification and characterisation of FA homologues in model organisms, such as Caenorhabditis elegans, will help facilitate an understanding of the function of the FA proteins by providing new analytical tools. To date, sequence homologues of five FA genes have been identified in C. elegans. Three of these homologues have been confirmed: brc-2 (FANCD1/BRCA2), fcd-2 (FANCD2), and dog-1 (FANCJ/BRIP1); and two remain to be characterised: W02D3.10 (FANCI) and drh-3 (FANCM). Here we review how the nematode can be used to study FA-associated DNA repair, focusing on what is known about the ICL repair genes in C. elegans and which important questions remain for the field. PMID:19059419

Youds, Jillian L; Barber, Louise J; Boulton, Simon J

2009-07-31

339

Drug Absorption Efficiency in Caenorhbditis elegans Delivered by Different Methods  

PubMed Central

Background Caenorhbditis elegans has being vigorously used as a model organism in many research fields and often accompanied by administrating with various drugs. The methods of delivering drugs to worms are varied from one study to another, which make difficult in comparing results between studies. Methodology/Principal Findings We evaluated the drug absorption efficiency in C. elegans using five frequently used methods with resveratrol with low aqueous solubility and water-soluble 5-Fluoro-2?-deoxyuridine (FUDR) as positive compounds. The drugs were either applied to the LB medium with bacteria OP50, before spreading onto Nematode Growth Medium (NGM) plates (LB medium method), or to the NGM with live (NGM live method) or dead bacteria (NGM dead method), or spotting the drug solution to the surface of plates directly (spot dead method), or growing the worms in liquid medium (liquid growing method). The concentration of resveratrol and FUDR increased gradually within C. elegans and reached the highest during 12 hours to one day and then decreased slowly. At the same time point, the higher the drug concentration, the higher the metabolism rate. The drug concentrations in worms fed with dead bacteria were higher than with live bacteria at the same time point. Consistently, the drug concentration in medium with live bacteria decreased much faster than in medium with dead bacteria, reach to about half of the original concentration within 12 hours. Conclusion Resveratrol with low aqueous solubility and water-soluble FUDR have the same absorption and metabolism pattern. The drug metabolism rate in worms was both dosage and time dependent. NGM dead method and liquid growing method achieved the best absorption efficiency in worms. The drug concentration within worms was comparable with that in mice, providing a bridge for dose translation from worms to mammals. PMID:23451103

Zheng, Shan-Qing; Ding, Ai-Jun; Li, Guo-Ping; Wu, Gui-Sheng; Luo, Huai-Rong

2013-01-01

340

Caenorhabditis elegans expresses a functional ArsA.  

PubMed

Because arsenic is the most prevalent environmental toxin, it is imperative that we understand the mechanisms of metalloid detoxification. In prokaryotes, arsenic detoxification is accomplished by chromosomal and plasmid-borne operon-encoded efflux systems. Bacterial ArsA ATPase is the catalytic component of an oxyanion pump that is responsible for resistance to arsenite (As(III)) and antimonite (Sb(III)). Here, we describe the identification of a Caenorhabditis elegans homolog (asna-1) that encodes the ATPase component of the Escherichia coli As(III) and Sb(III) transporter. We evaluated the responses of wild-type and asna-1-mutant nematodes to various metal ions and found that asna-1-mutant nematodes are more sensitive to As(III) and Sb(III) toxicity than are wild-type animals. These results provide evidence that ASNA-1 is required for C. elegans' defense against As(III) and Sb(III) toxicity. A purified maltose-binding protein (MBP)-ASNA-1 fusion protein was biochemically characterized, and its properties compared with those of ArsAs. The ATPase activity of the ASNA-1 protein was dependent on the presence of As(III) or Sb(III). As(III) stimulated ATPase activity by 2 +/- 0.2-fold, whereas Sb(III) stimulated it by 4.6 +/- 0.15-fold. The results indicate that As(III)- and Sb(III)-stimulated ArsA ATPase activities are not restricted to bacteria, but extend to animals, by demonstrating that the asna-1 gene from the nematode, C. elegans, encodes a functional ArsA ATPase whose activity is stimulated by As(III) and Sb(III) and which is critical for As(III) and Sb(III) tolerance in the intact organism. PMID:17419726

Tseng, Yuen-Yi; Yu, Chan-Wei; Liao, Vivian Hsiu-Chuan

2007-05-01

341

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

342

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

343

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

344

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

345

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

346

Oxidation of lynestrenol by the fungus Cunninghamella elegans.  

PubMed

Transformation of lynestrenol (19-nor-17alpha-pregn-4-en-20-yn-17beta-ol) (1) was carried out by incubation with Cunninghamella elegans to obtain 19-nor-17alpha-pregn-4-en-20-yn-3-one-10beta,17beta-diol (2), 19-nor-17alpha-pregn-4-en-20-yn-3-one-6beta,17beta-diol (3), and 19-nor-17alpha-pregn-4-en-20-yn-3beta,6beta,17beta-triol (4). Metabolite 4 was identified as a new compound. These metabolites were structurally characterised on the basis of spectroscopic techniques. PMID:20013465

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

2010-01-01

347

Biotransformation of flumequine by the fungus Cunninghamella elegans.  

PubMed

The metabolism of the antibacterial fluoroquinolone drug flumequine by Cunninghamella elegans was investigated using cultures grown in Sabouraud dextrose broth with 308microM flumequine. The cultures were extracted with ethyl acetate; metabolites were separated by high-performance liquid chromatography and identified by mass spectrometry and proton nuclear magnetic resonance spectroscopy. Flumequine was transformed to two diastereomers of 7-hydroxyflumequine (23 and 43% of the total chromatographic peak area at 280nm) and 7-oxoflumequine (11% of the total peak area). This is the first time that the two 7-hydroxy diastereomers have been characterized structurally; the hydroxyflumequines are known to have less antimicrobial activity than flumequine. PMID:17123578

Williams, Anna J; Deck, Joanna; Freeman, James P; Paul Chiarelli, M; Adjei, Michael D; Heinze, Thomas M; Sutherland, John B

2007-02-01

348

Posttranslational modifications of the basic peroxidase isoenzyme from Zinnia elegans  

Microsoft Academic Search

The major basic peroxidase (ZePrx) from Zinnia elegans suspension cell cultures was purified and cloned. The purification resolved ZePrxs in two isoforms (ZePrx33.44 and ZePrx34.70),\\u000a whose co-translational and post-translational modifications are characterized. Based on the N-terminal sequence obtained by\\u000a Edman degradation of mature ZePxs, it may be expected that the immature polypeptides of ZePrxs contain a signal peptide (N-terminal\\u000a pro-peptide)

Carlos Gabaldón; Laura V. Gómez-Ros; María J. López Núñez-Flores; Alberto Esteban-Carrasco; Alfonso Ros Barceló

2007-01-01

349

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

350

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

351

A Molecular Epidemiological Study of var Gene Diversity to Characterize the Reservoir of Plasmodium falciparum in Humans in Africa  

PubMed Central

Background The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite's ability to establish chronic infection and transmit from human to mosquito. Methodology/Principal Findings We investigated the molecular epidemiology of the var multigene family at local sites in Gabon, Senegal and Kenya which differ in parasite prevalence and transmission intensity. 1839 distinct var gene types were defined by sequencing DBL? domains in the three sites. Only 76 (4.1%) var types were found in more than one population indicating spatial heterogeneity in var types across the African continent. The majority of var types appeared only once in the population sample. Non-parametric statistical estimators predict in each population at minimum five to seven thousand distinct var types. Similar diversity of var types was seen in sites with different parasite prevalences. Conclusions/Significance Var population genomics provides new insights into the epidemiology of P. falciparum in Africa where malaria has never been conquered. In particular, we have described the extensive reservoir of infection in local African sites and discovered a unique var population structure that can facilitate superinfection through minimal overlap in var repertoires among parasite genomes. Our findings show that var typing as a molecular surveillance system defines the extent of genetic complexity in the reservoir of infection to complement measures of malaria prevalence. The observed small scale spatial diversity of var genes suggests that var genetics could greatly inform current malaria mapping approaches and predict complex malaria population dynamics due to the import of var types to areas where no widespread pre-existing immunity in the population exists. PMID:21347415

Leliwa-Sytek, Aleksandra; Smith, Terry-Ann; Peterson, Ingrid; Brown, Stuart M.; Migot-Nabias, Florence; Deloron, Philippe; Kortok, Moses M.; Marsh, Kevin; Daily, Johanna P.; Ndiaye, Daouda; Sarr, Ousmane; Mboup, Souleymane; Day, Karen P.

2011-01-01

352

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

353

Antiplasmodial sesquiterpenes from the seeds of Salacia longipes var. camerunensis.  

PubMed

Phytochemical investigation of the seeds of Salacia longipes var. camerunensis led to the isolation of four sesquiterpenoid derivatives, salaterpene A (1) (1?,2?,8?-triacetoxy-6?,9?-dibenzoyloxy-4?-hydroxy-dihydro-?-agarofuran), salaterpene B (2) (1?,2?,8?-triacetoxy-9?-benzoyloxy-6?-cinnamoyloxy-4?-hydroxy-dihydro-?-agarofuran), salaterpene C (3) (1?,2?-diacetoxy-6?,9?-dibenzoyloxy-4?-hydroxy-dihydro-?-agarofuran) and salaterpene D (4) (2?-acetoxy-1?,6?-dibenzoyloxy-4?-hydroxy-9?-nicotinoyloxy-dihydro-?-agarofuran) together with two known compounds (5 and 6). The structures of the compounds were established by means of NMR spectroscopy. Compounds 1-4 and 6 were tested in vitro for their antiplasmodial activity against Plasmodium falciparum chloroquine-resistant strain W2. All the tested compounds exhibited a moderate potency with IC50 below 2.7 ?M. PMID:23863332

Mba'ning, Brice M; Lenta, Bruno N; Noungoué, Diderot T; Antheaume, Cyril; Fongang, Yanick F; Ngouela, Silvère A; Boyom, Fabrice F; Rosenthal, Philip J; Tsamo, Etienne; Sewald, Norbert; Laatsch, Hartmut

2013-12-01

354

Triterpenoid saponins from rhizomes of Paris polyphylla var. yunnanensis.  

PubMed

Phytochemical investigation of the rhizomes of Paris polyphylla var. yunnanensis resulted in the isolation of six new oleanane-type triterpenoid saponins, paritrisides A-F (1-6), along with nine known triterpenoid saponins (7-15). The structures of the new compounds were elucidated on the basis of spectroscopic analysis and acid hydrolysis. All the triterpenoid saponins are obtained for the first time from the genus Paris. The isolated compounds were assayed for their cytotoxic activities against human nasopharyngeal carcinoma epithelial (CNE) cells, and compounds 7, 8, and 10 exhibited inhibitory effects on CNE cell growth with IC50 values of 16.53, 16.77, and 12.69 ?m, respectively. PMID:23305676

Wu, Xia; Wang, Lei; Wang, Guo-Cai; Wang, Hui; Dai, Yi; Yang, Xin-Xin; Ye, Wen-Cai; Li, Yao-Lan

2013-03-01

355

Utilization of Leek (Allium ampeloprasum var. porrum) for inulinase production.  

PubMed

Inulinase production by Rhodotorula glutinis was carried out in this study, using leek (Allium ampeloprasum var. porrum) as an alternative carbon source due to its high inulin content and easy availability. Taguchi orthogonal array (OA) design of experiment (DOE) was used to optimize fermentation conditions. For this purpose, five influential factors (leek concentration, pH, incubation temperature, agitation speed, and fermentation time) related to inulinase production were selected at four convenient levels. The results showed that maximum inulinase activity was obtained as 30.89 U/mL, which was close to the predicted result (30.24 U/mL). To validate the obtained results, analysis of variance (ANOVA) was employed. Consequently, leek has a great potential as an effective and economical carbon source for inulinase production, and the use of Taguchi DOE enhanced enzyme activity about 2.87-fold when compared with the unoptimized condition. PMID:25036570

Tasar, Ozden Canli; Erdal, Serkan; Algur, Omer Faruk

2015-08-18

356

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

357

Phosphorylation of SU(VAR)3-9 by the chromosomal kinase JIL-1.  

PubMed

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, Jørgen; Johansen, Kristen M; Becker, Peter B; Imhof, Axel

2010-01-01

358

Insights from the worm: the C. elegans model for innate immunity.  

PubMed

The nematode worm Caenorhabditis elegans comprises an ancestral immune system. C. elegans recognizes and responds to viral, bacterial, and fungal infections. Components of the RNA interference machinery respond to viral infection, while highly conserved MAPK signaling pathways activate the innate immune response to bacterial infection. C. elegans has been particularly important for exploring the role of innate immunity in organismal stress resistance and the regulation of longevity. Also functions of neuronal sensing of infectious bacteria have recently been uncovered. Studies on nematode immunity can be instructive in exploring innate immune signaling in the absence of specialized immune cells and adaptive immunity. PMID:24856329

Ermolaeva, Maria A; Schumacher, Björn

2014-08-01

359

Insights from the worm: The C. elegans model for innate immunity  

PubMed Central

The nematode worm Caenorhabditis elegans comprises an ancestral immune system. C. elegans recognizes and responds to viral, bacterial, and fungal infections. Components of the RNA interference machinery respond to viral infection, while highly conserved MAPK signaling pathways activate the innate immune response to bacterial infection. C. elegans has been particularly important for exploring the role of innate immunity in organismal stress resistance and the regulation of longevity. Also functions of neuronal sensing of infectious bacteria have recently been uncovered. Studies on nematode immunity can be instructive in exploring innate immune signaling in the absence of specialized immune cells and adaptive immunity. PMID:24856329

Ermolaeva, Maria A.; Schumacher, Björn

2014-01-01

360

miR-124/ATF-6, a novel lifespan extension pathway of Astragalus polysaccharide in Caenorhabditis elegans.  

PubMed

MicroRNAs (miRNAs), especially evolutionarily conserved miRNAs play critical roles in regulating various biological process. However, the functions of conserved miRNAs in longevity are still largely unknown. Astragalus polysaccharide (APS) was recently shown to extend lifespan of Caenorhabditis elegans, but its molecular mechanisms have not been fully understood. In the present study, we characterize that microRNA mediated a novel longevity pathway of APS in C. elegans. We found that APS markedly extended the lifespan of C. elegans at the second and the fourth stages. A highly conserved miRNA miR-124 was significantly upregulated in APS-treated C. elegans. Overexpression miR-124 caused the lifespan extension of C. elegans and vice versa, indicating miR-124 regulates the longevity of C. elegans. Using luciferase assay, atf-6 was established as a target gene of miR-124 which acting on three binding sites at atf-6 3'UTR. Consistently, agomir-cel-miR-124 was also shown to inhibit ATF-6 expression in C. elegans. APS-treated C. elegans showed the down-regulation of atf-6 at protein level. Furthermore, the knockdown of atf-6 by RNAi extended the lifespan of C. elegans, indicating atf-6 regulated by miR-124 contributes to lifespan extension. Taken together, miR-124 regulating ATF-6 is a new potential longevity signal pathway, which underlies the lifespan-extending effects of APS in C. elegans. PMID:25186652

Wang, Ning; Liu, Jing; Xie, Fang; Gao, Xu; Ye, Jian-Han; Sun, Lu-Yao; Wei, Ran; Ai, Jing

2015-02-01

361

Genistein from Vigna angularis Extends Lifespan in Caenorhabditis elegans  

PubMed Central

The seed of Vigna angularis has long been cultivated as a food or a folk medicine in East Asia. Genistein (4?,5,7-trihydroxyisoflavone), a dietary phytoestrogen present in this plant, has been known to possess various biological properties. In this study, we investigated the possible lifespan-extending effects of genistein using Caenorhabditis elegans model system. We found that the lifespan of nematode was significantly prolonged in the presence of genistein under normal culture condition. In addition, genistein elevated the survival rate of nematode against stressful environment including heat and oxidative conditions. Further studies demonstrated that genistein-mediated increased stress tolerance of nematode could be attributed to enhanced expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). Moreover, we failed to find genistein-induced significant change in aging-related factors including reproduction, food intake, and growth, indicating genistein exerts longevity activity independent of affecting these factors. Genistein treatment also led to an up-regulation of locomotory ability of aged nematode, suggesting genistein affects healthspan as well as lifespan of nematode. Our results represent that genistein has beneficial effects on the lifespan of C. elegans under both of normal and stress condition via elevating expressions of stress resistance proteins. PMID:25593647

Lee, Eun Byeol; Ahn, Dalrae; Kim, Ban Ji; Lee, So Yeon; Seo, Hyun Won; Cha, Youn-Soo; Jeon, Hoon; Eun, Jae Soon; Cha, Dong Seok; Kim, Dae Keun

2015-01-01

362

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

PubMed Central

Summary 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.

2013-01-01

363

Bacopa monnieri promotes longevity in Caenorhabditis elegans under stress conditions  

PubMed Central

Background: Bacopa monnieri (L.) Pennell, commonly known as Brahmi is an important medicinal plant traditionally used as memory enhancer and antiepileptic agent. Objective: The present study investigated antioxidant and stress resistance potentials of B. monnieri aqueous extract (BMW) using Caenorhabditis elegans animal model system. Materials and Methods: The antioxidant activity of the BMW was measured using in vitro (DPPH, reducing power and total polyphenol content) and in vivo (DCF-DA assay) assays. The antistress potential of BMW (0.1, 0.01, and 0.001 mg/ml) was evaluated through thermal stress (37°C) and oxidative stress (10 mM paraquat) using C. elegans. Quantification of the HSP-16.2 level was done using CL2070 transgenic worms. Results: Present study reveals that BMW possess in vitro and in vivo antioxidant activities. BMW significantly enhanced stress tolerance and increased the mean lifespan of worms during thermal and oxidative stress, although it did not extend lifespan at 20°C and attenuated age dependent decline in physiological behaviors. Moreover, it was shown that BMW was able to up-regulate expression of stress associated gene hsp-16.2, which significantly (P < 0.001) extends the mean lifespan of worms under stress conditions. Conclusion: The study strongly suggests that BMW acts as an antistressor and potent reactive oxygen species scavenger which enhances the survival of the worms in different stress conditions.

Phulara, Suresh C.; Shukla, Virendra; Tiwari, Sudeep; Pandey, Rakesh

2015-01-01

364

The Genetics of Levamisole Resistance in the Nematode CAENORHABDITIS ELEGANS  

PubMed Central

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 hypo-osmotic shock. Mutants with exceptional phenotypes suggest possible functions for several of the resistance loci. The most extreme mutants can readily be selected by their drug resistance (211 mutants, as many as 74 alleles of one gene). The more common resistance loci are likely to be unessential genes, while loci identified by only a few alleles may be essential genes or genes conferring resistance only when mutated in a special way. We propose that these mutants represent a favorable system for understanding how a small group of related genes function in a simple animal. The extreme drug resistance of these mutants makes them useful tools for the genetic manipulation of C. elegans. And, as the most resistant class of mutants might lack pharmacologically functional acetylcholine receptors (Lewis et al. 1980), these mutants may also be of some neurobiological significance. PMID:7203008

Lewis, James A.; Wu, C.-H.; Berg, Howard; Levine, Joseph H.

1980-01-01

365

Analysis of intraflagellar transport in C. elegans sensory cilia.  

PubMed

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 60 sensory neurons, each having sensory cilia on the endings of their dendrites, and most components of the IFT machinery operating in these structures have been identified using forward and reverse genetic approaches. By analyzing the rate of IFT along cilia within living wild-type and mutant animals, two anterograde and one retrograde IFT motors were identified, the functional coordination of the two anterograde kinesin-2 motors was established and the transport properties of all the known IFT particle components have been characterized. The anterograde kinesin motors have been heterologously expressed and purified, and their biochemical properties have been characterized using MT gliding and single molecule motility assays. In this chapter, we summarize how the tools of genetics, cell biology, electron microscopy, and biochemistry are being used to dissect the composition and mechanism of action of IFT motors and IFT particles in C. elegans. PMID:20409821

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

2009-01-01

366

Optimally wired subnetwork determines neuroanatomy of Caenorhabditis elegans  

PubMed Central

Wiring cost minimization has successfully explained many structures of nervous systems. However, in the nematode Caenorhabditis elegans, for which anatomical data are most detailed, wiring economy is thought to play only a partial role and alone has failed to account for the grouping of neurons into ganglia [Chen BL, Hall DH, Chklovskii DB (2006) Proc Natl Acad Sci USA 103:4723–4728; Kaiser M, Hilgetag CC (2006) PLoS Comput Biol 2:e95; Ahn Y-Y, Jeong H, Kim BJ (2006) Physica A 367:531–537]. Here, we test the hypothesis that optimally wired subnetworks can exist within nonoptimal networks, thus allowing wiring economy to give an improved prediction of spatial structure. We show in C. elegans that the small subnetwork of wires connecting sensory and motor neurons with sensors and muscles, comprising only 15% of connections, is close to optimal and alone predicts the main features of the spatial segregation of neurons into ganglia and encephalization. Moreover, a method to dissect networks into optimal and nonoptimal components is shown to find a large near-optimal subnetwork of 84% of neurons with a very low position error of 5.4%, and that explains clustering of neurons into ganglia and encephalization to fine detail. In general, we expect realistic networks not to be globally optimal in wire cost. We thus propose the strategy of using near-optimal subnetworks to understand neuroanatomical structure. PMID:17942697

Pérez-Escudero, Alfonso; de Polavieja, Gonzalo G.

2007-01-01

367

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

368

Acute Drug Treatment in the Early C. elegans Embryo  

PubMed Central

Genetic and genome-wide RNAi approaches available in C. elegans, combined with tools for visualizing subcellular events with high-resolution, have led to increasing adoption of the early C. elegans embryo as a model for mechanistic and functional genomic analysis of cellular processes. However, a limitation of this system has been the impermeability of the embryo eggshell, which has prevented the routine use of small molecule inhibitors. Here, we present a method to permeabilize and immobilize embryos for acute inhibitor treatment in conjunction with live imaging. To identify a means to permeabilize the eggshell, we used a dye uptake assay to screen a set of 310 candidate genes defined by a combination of bioinformatic criteria. This screen identified 20 genes whose inhibition resulted in >75% eggshell permeability, and 3 that permeabilized embryos with minimal deleterious effects on embryo production and early embryonic development. To mount permeabilized embryos for acute drug addition in conjunction with live imaging, we combined optimized inhibition of one of these genes with the use of a microfabricated chamber that we designed. We demonstrate that these two developments enable the temporally controlled introduction of inhibitors for mechanistic studies. This method should also open new avenues of investigation by allowing profiling and specificity-testing of inhibitors through comparison with genome-wide phenotypic datasets. PMID:21935434

Zhang, Kelly; Noble, Lisa B.; Zanin, Esther; Desai, Arshad; Groisman, Alex; Oegema, Karen

2011-01-01

369

Hierarchical sparse coding in the sensory system of Caenorhabditis elegans  

PubMed Central

Animals with compact sensory systems face an encoding problem where a small number of sensory neurons are required to encode information about its surrounding complex environment. Using Caenorhabditis elegans worms as a model, we ask how chemical stimuli are encoded by a small and highly connected sensory system. We first generated a comprehensive library of transgenic worms where each animal expresses a genetically encoded calcium indicator in individual sensory neurons. This library includes the vast majority of the sensory system in C. elegans. Imaging from individual sensory neurons while subjecting the worms to various stimuli allowed us to compile a comprehensive functional map of the sensory system at single neuron resolution. The functional map reveals that despite the dense wiring, chemosensory neurons represent the environment using sparse codes. Moreover, although anatomically closely connected, chemo- and mechano-sensory neurons are functionally segregated. In addition, the code is hierarchical, where few neurons participate in encoding multiple cues, whereas other sensory neurons are stimulus specific. This encoding strategy may have evolved to mitigate the constraints of a compact sensory system. PMID:25583501

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

2015-01-01

370

The ubiquitin proteasome system in Caenorhabditis elegans and its regulation?  

PubMed Central

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

Papaevgeniou, Nikoletta; Chondrogianni, Niki

2014-01-01

371

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

372

Evidence for biogenic pyromorphite formation by the nematode Caenorhabditis elegans.  

PubMed

The determination of chemical speciation and spatial distribution is a prerequisite for a mechanistic understanding of contaminant bioavailability and toxicity to an organism. We have employed synchrotron X-ray techniques to study Cu and Pb speciation and spatial distribution in the soil nematode Caenorhabditis elegans. Nematodes were exposed to each metal ion singly or simultaneously in solution for 24 h and were then rinsed thoroughly and preserved in formalin for transportation to the National Synchrotron Light Source. Experiments were conducted at the microprobe beamline X26A employing a focused beam of approximately 10 microm in diameter. Nematodes were mounted in agar gel on Kapton tape. Two-dimensional elemental maps for Cu- and Pb-exposed nematodes were collected in fluorescence mode. Copper was homogeneously distributed throughout the body of the nematode, but Pb exhibited a high degree of localization in the nematode, exclusively in the anterior pharynx region. Detectable localized concentrations of Pb in C. elegans occurred at aqueous exposure concentrations of 2.4 microM. Micro X-ray diffraction of these Pb hotspots gave a diffraction pattern indicating a crystalline Pb solid that was consistent with the Pb phosphate, pyromorphite. Biogenic inorganic phosphate granule formation is relatively common in soil invertebrates; however, these phosphates are typically amorphous, and we believe that this is the first report of crystalline pyromorphite formed internally in an organism. PMID:16124295

Jackson, B P; Williams, P L; Lanzirotti, A; Bertsch, P M

2005-08-01

373

Metabolism of methoxychlor by Cunninghamella elegans ATCC36112.  

PubMed

Methoxychlor is considered as pro-estrogen, while some of its metabolites are more potent endocrine disruptors than the parent insecticide. Major activation of methoxychlor is through cytochrome P450-catalyzed demethylation to bisphenol A-like metabolites. Cunninghamella elegans is a well-known fungal species with its strong resemblance of the xenobiotic metabolism of the mammalian system. In this study, the metabolism of methoxychlor was investigated with the corresponding organism. Methoxychlor was rapidly transformed to approximately 11 metabolites in phase I metabolism, including oxidation, hydroxylation, and dechlorination. Concentrations of phase I metabolites reached a maximum at 4-6 days and gradually decreased until the end of the experiments. Most metabolites from the phase I reaction were further transformed to sugar conjugates. Approximately 11 or more glucose conjugates were found in culture supernatants and gradually increased, while no glucuronides were observed throughout the experiments. Piperonyl butoxide and chlorpyrifos strongly inhibit the degradation of methoxychlor and concomitant accumulation of metabolites, indicating cytochrome P450 mediated metabolism. Little or no glycosides were detected in chlorpyrifos- and piperonyl butoxide-treated cultures. From the results, Cunninghamella elegans has shown strong similarities of the phase I metabolism of methoxychlor, while the conjugation reaction is different from those of animal metabolism. PMID:19691325

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

2009-09-01

374

Genistein from Vigna angularis Extends Lifespan in Caenorhabditis elegans.  

PubMed

The seed of Vigna angularis has long been cultivated as a food or a folk medicine in East Asia. Genistein (4',5,7-trihydroxyisoflavone), a dietary phytoestrogen present in this plant, has been known to possess various biological properties. In this study, we investigated the possible lifespan-extending effects of genistein using Caenorhabditis elegans model system. We found that the lifespan of nematode was significantly prolonged in the presence of genistein under normal culture condition. In addition, genistein elevated the survival rate of nematode against stressful environment including heat and oxidative conditions. Further studies demonstrated that genistein-mediated increased stress tolerance of nematode could be attributed to enhanced expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). Moreover, we failed to find genistein-induced significant change in aging-related factors including reproduction, food intake, and growth, indicating genistein exerts longevity activity independent of affecting these factors. Genistein treatment also led to an up-regulation of locomotory ability of aged nematode, suggesting genistein affects healthspan as well as lifespan of nematode. Our results represent that genistein has beneficial effects on the lifespan of C. elegans under both of normal and stress condition via elevating expressions of stress resistance proteins. PMID:25593647

Lee, Eun Byeol; Ahn, Dalrae; Kim, Ban Ji; Lee, So Yeon; Seo, Hyun Won; Cha, Youn-Soo; Jeon, Hoon; Eun, Jae Soon; Cha, Dong Seok; Kim, Dae Keun

2015-01-01

375

A Sexually Conditioned Switch of Chemosensory Behavior in C. elegans  

PubMed Central

In sexually reproducing animals, mating is essential for transmitting genetic information to the next generation and therefore animals have evolved mechanisms for optimizing the chance of successful mate location. In the soil nematode C. elegans, males approach hermaphrodites via the ascaroside pheromones, recognize hermaphrodites when their tails contact the hermaphrodites' body, and eventually mate with them. These processes are mediated by sensory signals specialized for sexual communication, but other mechanisms may also be used to optimize mate location. Here we describe associative learning whereby males use sodium chloride as a cue for hermaphrodite location. Both males and hermaphrodites normally avoid sodium chloride after associative conditioning with salt and starvation. However, we found that males become attracted to sodium chloride after conditioning with salt and starvation if hermaphrodites are present during conditioning. For this conditioning, which we call sexual conditioning, hermaphrodites are detected by males through pheromonal signaling and additional cue(s). Sex transformation experiments suggest that neuronal sex of males is essential for sexual conditioning. Altogether, these results suggest that C. elegans males integrate environmental, internal and social signals to determine the optimal strategy for mate location. PMID:23861933

Butcher, Rebecca A.; Clardy, Jon; Tomioka, Masahiro; Iino, Yuichi

2013-01-01

376

Regulation of transcription termination in the nematode Caenorhabditis elegans  

PubMed Central

The current predicted mechanisms that describe RNA polymerase II (pol II) transcription termination downstream of protein expressing genes fail to adequately explain, how premature termination is prevented in eukaryotes that possess operon-like structures. Here we address this issue by analysing transcription termination at the end of single protein expressing genes and genes located within operons in the nematode Caenorhabditis elegans. By using a combination of RT-PCR and ChIP analysis we found that pol II generally transcribes up to 1 kb past the poly(A) sites into the 3? flanking regions of the nematode genes before it terminates. We also show that pol II does not terminate after transcription of internal poly(A) sites in operons. We provide experimental evidence that five randomly chosen C. elegans operons are transcribed as polycistronic pre-mRNAs. Furthermore, we show that cis-splicing of the first intron located in downstream positioned genes in these polycistronic pre-mRNAs is critical for their expression and may play a role in preventing premature pol II transcription termination. PMID:19740764

Haenni, Simon; Sharpe, Helen E.; Gravato Nobre, Maria; Zechner, Kerstin; Browne, Cathy; Hodgkin, Jonathan; Furger, André

2009-01-01

377

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

378

Gait Modulation in C. elegans: An Integrated Neuromechanical Model  

PubMed Central

Equipped with its 302-cell nervous system, the nematode Caenorhabditis elegans adapts its locomotion in different environments, exhibiting so-called swimming in liquids and crawling on dense gels. Recent experiments have demonstrated that the worm displays the full range of intermediate behaviors when placed in intermediate environments. The continuous nature of this transition strongly suggests that these behaviors all stem from modulation of a single underlying mechanism. We present a model of C. elegans forward locomotion that includes a neuromuscular control system that relies on a sensory feedback mechanism to generate undulations and is integrated with a physical model of the body and environment. We find that the model reproduces the entire swim-crawl transition, as well as locomotion in complex and heterogeneous environments. This is achieved with no modulatory mechanism, except via the proprioceptive response to the physical environment. Manipulations of the model are used to dissect the proposed pattern generation mechanism and its modulation. The model suggests a possible role for GABAergic D-class neurons in forward locomotion and makes a number of experimental predictions, in particular with respect to non-linearities in the model and to symmetry breaking between the neuromuscular systems on the ventral and dorsal sides of the body. PMID:22408616

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

2012-01-01

379

Meiotic Recombination, Noncoding DNA and Genomic Organization in Caenorhabditis Elegans  

PubMed Central

The genetic map of each Caenorhabditis elegans chromosome has a central gene cluster (less pronounced on the X chromosome) that contains most of the mutationally defined genes. Many linkage group termini also have clusters, though involving fewer loci. We examine the factors shaping the genetic map by analyzing the rate of recombination and gene density across the genome using the positions of cloned genes and random cDNA clones from the physical map. Each chromosome has a central gene-dense region (more diffuse on the X) with discrete boundaries, flanked by gene-poor regions. Only autosomes have reduced rates of recombination in these gene-dense regions. Cluster boundaries appear discrete also by recombination rate, and the boundaries defined by recombination rate and gene density mostly, but not always, coincide. Terminal clusters have greater gene densities than the adjoining arm but similar recombination rates. Thus, unlike in other species, most exchange in C. elegans occurs in gene-poor regions. The recombination rate across each cluster is constant and similar; and cluster size and gene number per chromosome are independent of the physical size of chromosomes. We propose a model of how this genome organization arose. PMID:8536965

Barnes, T. M.; Kohara, Y.; Coulson, A.; Hekimi, S.

1995-01-01

380

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

381

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

382

Evaluation of the influence of fullerenol on aging and stress resistance using Caenorhabditis elegans.  

PubMed

Fullerene derivatives have attracted extensive attention in biomedical fields and polyhydroxyl fullerene (fullerenol), a water-soluble fullerene derivative, is demonstrated as a powerful antioxidant. To further assess their anti-aging and anti-stress potential, we employed Caenorhabditis elegans (C. elegans) as a model organism to evaluate the effects of fullerenol on the growth, development, behavior and anti-stress ability in vivo. The data show that fullerenol has no obviously toxic effect on nematodes and can delay C. elegans aging progress under normal condition. Further studies demonstrate that fullerenol attenuates endogenous levels of reactive oxygen species and provides protection to C. elegans under stress conditions by up-regulating stress-related genes in a DAF-16 depend manner and improving lifespan. In summary, our data suggest that fullerenol might be a safe and reasonable anti-aging candidate with great potential in vivo. PMID:25542795

Cong, Wenshu; Wang, Peng; Qu, Ying; Tang, Jinglong; Bai, Ru; Zhao, Yuliang; Chunying Chen; Bi, Xiaolin

2015-02-01

383

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

384

A Movable Surface: Formation of Yersinia sp. Biofilms on Motile Caenorhabditis elegans  

PubMed Central

Bubonic plague is transmitted by fleas whose feeding is blocked by a mass of Yersinia pestis in the digestive tract. Y. pestis and the closely related Y. pseudotuberculosis also block the feeding of Caenorhabditis elegans by forming a biofilm on the nematode head. C. elegans mutants with severe motility defects acquire almost no biofilm, indicating that normal animals accumulate the biofilm matrix as they move through a Yersinia lawn. Using the lectin wheat germ agglutinin as a probe, we show that the matrix on C. elegans contains carbohydrate produced by Yersinia. The carbohydrate is present in bacterial lawns prior to addition of nematodes, indicating that biofilm formation does not involve signaling between the two organisms. Furthermore, biofilm accumulation depends on continuous C. elegans exposure to a lawn of Yersinia bacteria. PMID:15262945

Tan, Li; Darby, Creg

2004-01-01

385

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.

386

Characterization of a conserved apoptotic marker expressed in Caenorhabditis elegans phagocytic cells  

E-print Network

to live or die. These genes, which include egl-1, ced-9, and ced-4, control the activity of CED-3, a cas- pase that initiates the cellular changes that occur during apoptosis. In C. elegans, CED-3 regulates

Hermann, Greg J.

387

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

388

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.

389

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

390

The sys-1 Gene and Sexual Dimorphism during Gonadogenesis in Caenorhabditis elegans  

E-print Network

Press Key Words: sys-1; gonadogenesis; sexual dimorphism; C. elegans. INTRODUCTION During organogenesis of organogenesis. This organ is sufficiently simple that it can be dissected genetically and analyzed at the level

Kimble, Judith

391

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

PubMed

Genetic conservation allows ancient features of fat storage endocrine pathways to be explored in C. elegans. Multiple studies have used Nile red or BODIPY-labeled fatty acids to identify regulators of fat mass. When mixed with their food, E. coli bacteria, Nile red, and BODIPY-labeled fatty acids stain multiple spherical cellular structures in the C. elegans major fat storage organ, the intestine. However, here we demonstrate that, in the conditions previously reported, the lysosome-related organelles stained by Nile red and BODIPY-labeled fatty acids are not the C. elegans major fat storage compartment. We show that the major fat stores are contained in a distinct cellular compartment that is not stained by Nile red. Using biochemical assays, we validate oil red O staining as a method to assess major fat stores in C. elegans, allowing for efficient and accurate genetic and functional genomic screens for genes that control fat accumulation at the organismal level. PMID:19883620

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

2009-11-01

392

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.

393

Alpha-Synuclein Disrupted Dopamine Homeostasis Leads to Dopaminergic Neuron Degeneration in Caenorhabditis elegans  

E-print Network

Disruption of dopamine homeostasis may lead to dopaminergic neuron degeneration, a proposed explanation for the specific vulnerability of dopaminergic neurons in Parkinson's disease. While expression of human ?-synuclein in C. elegans results...

Cao, Pengxiu; Yuan, Yiyuan; Pehek, Elizabeth A.; Moise, Alexander R.; Huang, Ying; Palczewski, Krzysztof; Feng, Zhaoyang

2010-02-19

394

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

PubMed

Inspired by its simple musculature, actuation and motion mechanisms, we have developed a small crawling robot that closely mimics the model organism of our choice: Caenorhabditis elegans. A thermal shape memory alloy (SMA) was selected as an actuator due to the similarities of its properties to C. elegans muscles. Based on the anatomy of C. elegans, a 12-unit robot was designed to generate a sinusoidal undulating motion. Each body unit consisting of a pair of SMA actuators is serially connected by rigid links with an embedded motion control circuit. A simple binary operation-based motion control mechanism was implemented using a microcontroller. The assembled robot can execute C. elegans-like motion with a 0.17 Hz undulation frequency. Its motion is comparable to that of a real worm. PMID:21992959

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

2011-12-01

395

Acceleration of tributyltin chloride (TBT) degradation in liquid cultures of the filamentous fungus Cunninghamella elegans.  

PubMed

In this study, we have examined the effects of synthetic medium ingredients and culture incubation conditions on growth and tributyltin chloride (TBT) degradation activity of the fungus Cunninghamella elegans. The best efficiency of TBT conversion to less toxic derivatives: dibutyltin and monobutyltin was noticed on media which contained glucose, NH(4)Cl, K(2)HPO(4) and MgSO(4). Next, the constructed M3 medium (with the above components) ensured vigorous growth of C. elegans and allowed the reduction of 80% of the initial TBT content (10 mg l(-1)), after 3d of biodegradation. The further acceleration of the biocide utilization by C. elegans was achieved by additional oxygen supply (pO(2) >or = 20%) to the growing fungus (89% after 2d of incubation in the BioFlo II bioreactor). The efficient xenobiotic biodegradation was related to the intensity of fungal growth. The obtained results suggest a cometabolic nature of TBT utilization by C. elegans. PMID:15961138

Bernat, Przemys?aw; D?ugo?ski, Jerzy

2006-01-01

396

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

PubMed

Genome editing based on CRISPR (clustered regularly interspaced short palindromic repeats)-associated nuclease (Cas9) has been successfully applied in dozens of diverse plant and animal species, including the nematode Caenorhabditis elegans. The rapid life cycle and easy access to the ovary by micro-injection make C. elegans an ideal organism both for applying CRISPR-Cas9 genome editing technology and for optimizing genome-editing protocols. Here we report efficient and straightforward CRISPR-Cas9 genome-editing methods for C. elegans, including a Co-CRISPR strategy that facilitates detection of genome-editing events. We describe methods for detecting homologous recombination (HR) events, including direct screening methods as well as new selection/counterselection strategies. Our findings reveal a surprisingly high frequency of HR-mediated gene conversion, making it possible to rapidly and precisely edit the C. elegans genome both with and without the use of co-inserted marker genes. PMID:24879462

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

2014-08-01

397

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.

398

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

399

Suppression of polyglutamine-induced protein aggregation in Caenorhabditis elegans by torsin  

E-print Network

elegantly linked to a specific deletion of a codon (GAG) in a gene termed DYT1 (TOR1A) (4,5) and more aggregate formation. Antibody staining of transgenic animals indicated that both the C. elegans torsin

Caldwell, Guy

400

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

401

Many families of Caenorhabditis elegans microRNAs are not essential for development or viability  

E-print Network

MicroRNAs (miRNAs) are approximately 23 nt regulatory RNAs that posttranscriptionally inhibit the functions of protein-coding mRNAs. We previously found that most C. elegans miRNAs are individually not essential for ...

Alvarez-Saavedra, Ezequiel

402

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

PubMed

Males of the androdioecious species Caenorhabditis elegans are more likely to attempt to mate with and successfully inseminate C. elegans hermaphrodites that do not concurrently harbor sperm. Although a small number of genes have been implicated in this effect, the mechanism by which it arises remains unknown. In the context of the battle of the sexes, it is also unknown whether this effect is to the benefit of the male, the hermaphrodite, or both. We report that successful contact between mature sperm and oocyte in the C. elegans gonad at the start of fertilization causes the oocyte to release a signal that is transmitted to somatic cells in its mother, with the ultimate effect of reducing her attractiveness to males. Changes in hermaphrodite attractiveness are tied to the production of a volatile pheromone, the first such pheromone described in C. elegans. PMID:25453110

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

2014-12-16

403

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.

404

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.

405

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.

406

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.

407

Antiviral efficacy against hepatitis B virus replication of oleuropein isolated from Jasminum officinale L. var. grandiflorum  

Microsoft Academic Search

Ethnopharmacological relevanceJasminum officinale L. var. grandiflorum (JOG) is a folk medicine used for the treatment of hepatitis in south of China. Phytochemical studies showed that secoiridoid glycosides are the typical constituents of this plant.

Guiqin Zhao; Zhifeng Yin; Junxing Dong

2009-01-01

408

Changes in seagrass polychaete assemblages after invasion by Caulerpa racemosa var. cylindracea  

E-print Network

(Chlorophyta: Caulerpales): community structure, trophic guilds and taxonomic distinctness ANTONIO BOX 1 invasión de Caulerpa raCemosa var. CylindraCea (Chlorophyta: Caulerpales): estructura de comunidad

Martin, Daniel

409

Var gene transcription and clinical disease manifestation in African P. falciparum malaria field isolates   

E-print Network

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variant surface antigens, encoded by the var gene family, play a crucial role in malaria pathogenesis through mediating immunomodulation and host cell ...

Kyriacou, Helen M

2008-01-01

410

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

411

Characterization of taurine as anti-obesity agent in C. elegans  

Microsoft Academic Search

BACKGROUND: Taurine plays an important role in reducing physiological stress. Recent studies indicated that taurine may serve as an anti-obesity agent at the cellular level. This study characterizes taurine’s potential anti-obesity function in C. elegans, which have become a popular in vivo model for understanding the regulatory basis of lipid biosynthesis and deposition. METHODS: Two strains of C. elegans were

Hye Min Kim; Chang-Hee Do; Dong Hee Lee

2010-01-01

412

C. elegans ATAD-3 Is Essential for Mitochondrial Activity and Development  

Microsoft Academic Search

BackgroundMammalian ATAD3 is a mitochondrial protein, which is thought to play an important role in nucleoid organization. However, its exact function is still unresolved.ResultsHere, we characterize the Caenorhabditis elegans (C. elegans) ATAD3 homologue (ATAD-3) and investigate its importance for mitochondrial function and development. We show that ATAD-3 is highly conserved among different species and RNA mediated interference against atad-3 causes

Michael Hoffmann; Nadège Bellance; Rodrigue Rossignol; Werner J. H. Koopman; Peter H. G. M. Willems; Ertan Mayatepek; Olaf Bossinger; Felix Distelmaier; Thomas Zwaka

2009-01-01

413

C. elegans ced-13 can promote apoptosis and is induced in response to DNA damage  

Microsoft Academic Search

The p53 tumor suppressor promotes apoptosis in response to DNA damage. Here we describe the Caenorhabditis elegans gene ced-13, which encodes a conserved BH3-only protein. We show that ced-13 mRNA accumulates following DNA damage, and that this accumulation is dependent on an intact C. elegans cep-1\\/p53 gene. We demonstrate that CED-13 protein physically interacts with the antiapoptotic Bcl-2-related protein CED-9.

B Schumacher; C Schertel; N Wittenburg; S Tuck; S Mitani; A Gartner; B Conradt; S Shaham

2005-01-01

414

Caenorhabditis elegans Protein Arginine Methyltransferase PRMT-5 Negatively Regulates DNA Damage-Induced Apoptosis  

Microsoft Academic Search

Arginine methylation of histone and non-histone proteins is involved in transcription regulation and many other cellular processes. Nevertheless, whether such protein modification plays a regulatory role during apoptosis remains largely unknown. Here we report that the Caenorhabditis elegans homolog of mammalian type II arginine methyltransferase PRMT5 negatively regulates DNA damage-induced apoptosis. We show that inactivation of C. elegans prmt-5 leads

Mei Yang; Jianwei Sun; Xiaojuan Sun; Qinfang Shen; Zhiyang Gao; Chonglin Yang

2009-01-01

415

Caenorhabditis elegans CED9 protein is a bifunctional cell-death inhibitor  

Microsoft Academic Search

The Caenorhabditis elegans gene ced-9 prevents cells from undergoing programmed cell death and encodes a protein similar to the mammalian cell-death inhibitor Bcl-2 (refs 1,2,3,4,5,6,7). We show here that the CED-9 protein is a substrate for the C. elegans cell-death protease CED-3 (refs 8, 9), which is a member of a family of cysteine proteases first defined by CED-3 and

Ding Xue; H. Robert Horvitz

1997-01-01

416

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

417

Impact of Cigarette Smoke Exposure on Innate Immunity: A Caenorhabditis elegans Model  

Microsoft Academic Search

BackgroundCigarette smoking is the major cause of chronic obstructive pulmonary disease (COPD) and lung cancer. Respiratory bacterial infections have been shown to be involved in the development of COPD along with impaired airway innate immunity.Methodology\\/Principal FindingsTo address the in vivo impact of cigarette smoke (CS) exclusively on host innate defense mechanisms, we took advantage of Caenorhabditis elegans (C. elegans), which

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

2009-01-01

418

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

419

Oxidation of cinnamyl alcohols and aldehydes by a basic peroxidase from lignifying Zinnia elegans hypocotyls  

Microsoft Academic Search

The xylem of 26-day old Zinnia elegans hypocotyls synthesizes lignins derived from coniferyl alcohol and sinapyl alcohol with a G\\/S ratio of 43\\/57 in the aryl-glycerol-?-aryl ether core, as revealed by thioacidolysis. Thioacidolysis of Z. elegans lignins also reveals the presence of coniferyl aldehyde end groups linked by ?-0-4 bonds. Both coniferyl and sinapyl alcohols, as well as coniferyl and

A. Ros Barceló; F. Pomar

2001-01-01

420

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

421

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

PubMed Central

The genetically tractable model host Caenorhabditis elegans provides a valuable tool to dissect host-microbe interactions in vivo. Pseudomonas aeruginosa and Staphylococcus aureus utilize virulence factors involved in human disease to infect and kill C. elegans. Despite much progress, virtually nothing is known regarding the cytopathology of infection and the proximate causes of nematode death. Using light and electron microscopy, we found that P. aeruginosa infection entails intestinal distention, accumulation of an unidentified extracellular matrix and P. aeruginosa-synthesized outer membrane vesicles in the gut lumen and on the apical surface of intestinal cells, the appearance of abnormal autophagosomes inside intestinal cells, and P. aeruginosa intracellular invasion of C. elegans. Importantly, heat-killed P. aeruginosa fails to elicit a significant host response, suggesting that the C. elegans response to P. aeruginosa is activated either by heat-labile signals or pathogen-induced damage. In contrast, S. aureus infection causes enterocyte effacement, intestinal epithelium destruction, and complete degradation of internal organs. S. aureus activates a strong transcriptional response in C. elegans intestinal epithelial cells, which aids host survival during infection and shares elements with human innate responses. The C. elegans genes induced in response to S. aureus are mostly distinct from those induced by P. aeruginosa. In contrast to P. aeruginosa, heat-killed S. aureus activates a similar response as live S. aureus, which appears to be independent of the single C. elegans Toll-Like Receptor (TLR) protein. These data suggest that the host response to S. aureus is possibly mediated by pathogen-associated molecular patterns (PAMPs). Because our data suggest that neither the P. aeruginosa nor the S. aureus–triggered response requires canonical TLR signaling, they imply the existence of unidentified mechanisms for pathogen detection in C. elegans, with potentially conserved roles also in mammals. PMID:20617181

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

2010-01-01

422

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

PubMed

The genetically tractable model host Caenorhabditis elegans provides a valuable tool to dissect host-microbe interactions in vivo. Pseudomonas aeruginosa and Staphylococcus aureus utilize virulence factors involved in human disease to infect and kill C. elegans. Despite much progress, virtually nothing is known regarding the cytopathology of infection and the proximate causes of nematode death. Using light and electron microscopy, we found that P. aeruginosa infection entails intestinal distention, accumulation of an unidentified extracellular matrix and P. aeruginosa-synthesized outer membrane vesicles in the gut lumen and on the apical surface of intestinal cells, the appearance of abnormal autophagosomes inside intestinal cells, and P. aeruginosa intracellular invasion of C. elegans. Importantly, heat-killed P. aeruginosa fails to elicit a significant host response, suggesting that the C. elegans response to P. aeruginosa is activated either by heat-labile signals or pathogen-induced damage. In contrast, S. aureus infection causes enterocyte effacement, intestinal epithelium destruction, and complete degradation of internal organs. S. aureus activates a strong transcriptional response in C. elegans intestinal epithelial cells, which aids host survival during infection and shares elements with human innate responses. The C. elegans genes induced in response to S. aureus are mostly distinct from those induced by P. aeruginosa. In contrast to P. aeruginosa, heat-killed S. aureus activates a similar response as live S. aureus, which appears to be independent of the single C. elegans Toll-Like Receptor (TLR) protein. These data suggest that the host response to S. aureus is possibly mediated by pathogen-associated molecular patterns (PAMPs). Because our data suggest that neither the P. aeruginosa nor the S. aureus-triggered response requires canonical TLR signaling, they imply the existence of unidentified mechanisms for pathogen detection in C. elegans, with potentially conserved roles also in mammals. PMID:20617181

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

2010-01-01

423

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

Microsoft Academic Search

A study was done to characterize the shedding of foodborne pathogenic bacteria by Caenorhabditis elegans, evaluate the persistence of worm populations cocultured with foodborne pathogens, and determine if C. elegans disperses ingested pathogens in soil as a result of shedding. Escherichia. coli O157:H7, Salmonella enterica serotype Poona, and Listeria monocytogenes, as well as E. coli OP50, a non-pathogenic strain, were

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

2006-01-01

424

Genetic identification of Saccharomyces bayanus var. uvarum, a cider-fermenting yeast  

Microsoft Academic Search

Twenty-one Saccharomyces strains isolated from a cider process were analysed in terms of karyotypes, Y? S. cerevisiae sequence occurrence, rDNA structure and cross-fertility with species tester strains. A strong predominance of S. bayanus var. uvarum G. Naumov was found (18 strains vs. three S. cerevisiae). Among the S. bayanus var. uvarum, only three strains proved to contain species-specific Y? S.

G. I Naumov; H.-V Nguyen; E. S Naumova; A Michel; M Aigle; C Gaillardin

2001-01-01

425

Genome Sequence of Phytophthora fragariae var. fragariae, a Quarantine Plant-Pathogenic Fungus  

PubMed Central

Phytophthora fragariae var. fragariae is a serious plant-pathogenic fungus causing red core disease in strawberries, resulting in a larger number of fruit produced, and the fungus has been regulated as a quarantine pest of many countries and regions. Here, we announce the genome sequence of P. fragariae var. fragariae, and this information might provide insight into the mechanism of pathogenicity and host specificity of this pathogen, as well as help us further identify targets for fungicides. PMID:25814589

Gao, Ruifang; Cheng, Yinghui; Wang, Ying; Wang, Ying; Guo, Liyun

2015-01-01

426

Morphological, anatomical and cytological investigation on endemic Lamium moschatum var. rhodium  

Microsoft Academic Search

In this study, the morphological and anatomical features of endemic Lamium moschatum Miller var. rhodium (Gand.) R. Mill (Lamiaceae) are described in detail. Lamium moschatum var. rhodium has an annual taproot. The stem is erect and clearly quadrangular. The leaves are broadly ovate to cordate-ovate or nearly\\u000a suborbicular in shape. Inflorescense is verticillate cyme. The corolla is white and the

Pelin Baran; Canan Özdemir

2011-01-01

427

Determination of kinetic properties of polyphenol oxidase from Thymus ( Thymus longicaulis subsp. chaubardii var. chaubardii)  

Microsoft Academic Search

A partial characterization of polyphenol oxidase (PPO) activity of Thymus longicaulis subsp. chaubardii var. chaubardii is described. Polyphenol oxidase of Thymus was isolated by (NH4)2SO4 precipitation and dialysis. The effects of substrate specificity, pH, temperature, heat-inactivation and glutathione inhibitor on polyphenol oxidase activity obtained from T. longicaulis subsp. chaubardii var. chaubardii were investigated. Polyphenol oxidase showed activity toward catechol, 4-methylcatechol

Serap Dogan; Mehmet Dogan

2004-01-01

428

[Comparison between content of saponins of Paris polyphylla var. yunnanensis in different areas of Yunnan province].  

PubMed

Six kinds of saponins (I, II, VII, PA, H) content of 22 samples of Paris polyphylla var. yunnanensis collected from different regions of Yunnan province were determined by HPLC, data was analyzed by SPSS 17. The results showed that the effect of altitude on saponin content was not significant, and the effect of growth area of saponins in P. polyphylla var. yunnanensis was significant, saponin content in sample from west Yunnan was significantly higher than that of samples from other regions. PMID:25204168

Li, Hai-Tao; Luo, Xian-Wen; Guan, Yan-Hong; Zhang, Li-Xia; Gao, Wei-Wei

2014-03-01

429

Molecular Cloning and Characterization of the Insecticidal Crystal Protein Gene of Bacillus thuringiensis Var. Tenebrionis  

Microsoft Academic Search

The insecticidal crystal protein gene of the coleopteran-toxic Bacillus thuringiensis var. tenebrionis has been isolated, and the nucleotide sequence has been determined. A total DNA library from var. tenebrionis was made in the plasmid vector pUC12. By using a synthetic 27-base oligonucleotide corresponding to a stretch of nine N-terminal amino acids of a tryptic fragment of purified crystal protein of

Vaithilingam Sekar; David V. Thompson; Michael J. Maroney; Roger G. Bookland; Michael J. Adang

1987-01-01

430

Valeur alimentaire de rgimes base de cactus inerme (Opunfia ficus indica var. Inermis) et  

E-print Network

Valeur alimentaire de régimes à base de cactus inerme (Opunfia ficus indica var. Inermis) et d régimes à base de cactus inerme (Opuntia ficus indica, var. Inermis) et d'Atriplex nummularia. Quinze aléatoire en trois lots de cinq têtes chacun. Chaque lot a reçu un régime composé d'atriplex et de cactus en

Paris-Sud XI, Université de

431

Genome Sequence of Phytophthora fragariae var. fragariae, a Quarantine Plant-Pathogenic Fungus.  

PubMed

Phytophthora fragariae var. fragariae is a serious plant-pathogenic fungus causing red core disease in strawberries, resulting in a larger number of fruit produced, and the fungus has been regulated as a quarantine pest of many countries and regions. Here, we announce the genome sequence of P. fragariae var. fragariae, and this information might provide insight into the mechanism of pathogenicity and host specificity of this pathogen, as well as help us further identify targets for fungicides. PMID:25814589

Gao, Ruifang; Cheng, Yinghui; Wang, Ying; Wang, Ying; Guo, Liyun; Zhang, Guiming

2015-01-01

432

Fatty acids of canola Brassica campestris var candle seed and oils at various stages of refining  

Microsoft Academic Search

Fatty acids of oil of a current variety of canolaBrassica campestris var Candle, at 3 stages of commercial production and refining, were compared with authentic seed oils, and with the oil ofB. napus var Tower. The proportion ofcis- 9, cis- 12, trans- 15 andtrans- 9, cis-12, cis-lS-octadecatrienoates relative to the all-cis isomer was lower than that previously observed in processed

J. L. Sebedio; R. G. Ackman

1981-01-01

433

Differential var gene transcription in Plasmodium falciparum isolates from patients with cerebral malaria compared to hyperparasitaemia  

Microsoft Academic Search

The Plasmodium falciparum variant erythrocyte surface antigens known as PfEMP1, encoded by the var gene family, are thought to play a crucial role in malaria pathogenesis because they mediate adhesion to host cells and immuno-modulation. Var genes have been divided into three major groups (A, B and C) and two intermediate groups (B\\/A and B\\/C) on the basis of their

Helen M. Kyriacou; Graham N. Stone; Richard J. Challis; Ahmed Raza; Kirsten E. Lyke; Mahamadou A. Thera; Abdoulaye K. Koné; Ogobara K. Doumbo; Christopher V. Plowe; J. Alexandra Rowe

2006-01-01

434

Growth and Mating of Cryptococcus neoformans var. grubii on Woody Debris  

Microsoft Academic Search

A total of 36 Cryptococcus neoformans strains originating from South Africa were screened for wood degrading enzymes. All strains tested positive for cellulase\\u000a activity while none where capable of xylan degradation. Three C. neoformans var. grubii strains, originating from clinical and environmental samples, representing the same genotype (VNI\\/AFLP1—C. neoformans var. grubii) and MAT?, were evaluated for growth on debris of

A. Botes; T. Boekhout; F. Hagen; H. Vismer; J. Swart; A. Botha

2009-01-01

435

Design and installation of a ±250 kVAr D-STATCOM for a distribution substation  

Microsoft Academic Search

A Static Compensator (STATCOM) is a flexible ac transmission system (FACTS) controller, which can either absorb or deliver reactive power to a power system. This technology has resulted in an equipment that is principally different from conventional static VAr compensators (SVC). The steady-state characteristics of a STATCOM are similar to those of a rotating synchronous condenser. A ±250kVAr D-STATCOM was

M. Tavakoli Bina; M. D. Eskandari; M. Panahlou

2005-01-01

436

E. coli OxyS non-coding RNA does not trigger RNAi in C. elegans  

PubMed Central

The discovery of RNA interference (RNAi) in C. elegans has had a major impact on scientific research, led to the rapid development of RNAi tools and has inspired RNA-based therapeutics. Astonishingly, nematodes, planaria and many insects take up double-stranded RNA (dsRNA) from their environment to elicit RNAi; the biological function of this mechanism is unclear. Recently, the E. coli OxyS non-coding RNA was shown to regulate gene expression in C. elegans when E. coli is offered as food. This was surprising given that C. elegans is unlikely to encounter E. coli in nature. To directly test the hypothesis that the E. coli OxyS non-coding RNA triggers the C. elegans RNAi pathway, we sequenced small RNAs from C. elegans after feeding with bacteria. We clearly demonstrate that the OxyS non-coding RNA does not trigger an RNAi response in C. elegans. We conclude that the biology of environmental RNAi remains to be discovered. PMID:25873159

Akay, Alper; Sarkies, Peter; Miska, Eric A.

2015-01-01

437

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

438

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

SciTech Connect

Highlights: •We have determined solution structures of CEH-37 homedomain. •CEH-37 HD has a compact ?-helical structure with HTH DNA binding motif. •Solution structure of CEH-37 HD shares its molecular topology with that of the homeodomain proteins. •Residues in the N-terminal region and HTH motif are important in binding to Caenorhabditis elegans telomeric DNA. •CEH-37 could play an important role in telomere function via DNA binding. -- Abstract: The nematode Caenorhabditis elegans protein CEH-37 belongs to the paired OTD/OTX family of homeobox-containing homeodomain proteins. CEH-37 shares sequence similarity with homeodomain proteins, although it specifically binds to double-stranded C. elegans telomeric DNA, which is unusual to homeodomain proteins. Here, we report the solution structure of CEH-37 homeodomain and molecular interaction with double-stranded C. elegans telomeric DNA using nuclear magnetic resonance (NMR) spectroscopy. NMR structure shows that CEH-37 homeodomain is composed of a flexible N-terminal region and three ?-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.

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

2014-01-10

439

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

440

E. coli OxyS non-coding RNA does not trigger RNAi in C. elegans.  

PubMed

The discovery of RNA interference (RNAi) in C. elegans has had a major impact on scientific research, led to the rapid development of RNAi tools and has inspired RNA-based therapeutics. Astonishingly, nematodes, planaria and many insects take up double-stranded RNA (dsRNA) from their environment to elicit RNAi; the biological function of this mechanism is unclear. Recently, the E. coli OxyS non-coding RNA was shown to regulate gene expression in C. elegans when E. coli is offered as food. This was surprising given that C. elegans is unlikely to encounter E. coli in nature. To directly test the hypothesis that the E. coli OxyS non-coding RNA triggers the C. elegans RNAi pathway, we sequenced small RNAs from C. elegans after feeding with bacteria. We clearly demonstrate that the OxyS non-coding RNA does not trigger an RNAi response in C. elegans. We conclude that the biology of environmental RNAi remains to be discovered. PMID:25873159

Akay, Alper; Sarkies, Peter; Miska, Eric A

2015-01-01

441

Efficient transformation and expression of gfp gene in Valsa mali var. mali.  

PubMed

Valsa mali var. mali, the causal agent of valsa canker of apple, causes great loss of apple production in apple producing regions. The pathogenic mechanism of the pathogen has not been studied extensively, thus a suitable gene marker for pathogenic invasion analysis and a random insertion of T-DNA for mutants are desirable. In this paper, we reported the construction of a binary vector pKO1-HPH containing a positive selective gene hygromycin phosphotransferase (hph), a reporter gene gfp conferring green fluorescent protein, and an efficient protocol for V. mali var. mali transformation mediated by Agrobacterium tumefaciens. A transformation efficiency up to about 75 transformants per 10(5) conidia was achieved when co-cultivation of V. mali var. mali and A. tumefaciens for 48 h in A. tumefaciens inductive medium agar plates. The insertions of hph gene and gfp gene into V. mali var. mali genome verified by polymerase chain reaction and southern blot analysis showed that 10 randomly-selected transformants exhibited a single, unique hybridization pattern. This is the first report of A. tumefaciens-mediated transformation of V. mali var mali carrying a 'reporter' gfp gene that stably and efficiently expressed in the transformed V. mali var. mali species. PMID:25423905

Chen, Liang; Sun, Gengwu; Wu, Shujing; Liu, Huixiang; Wang, Hongkai

2015-01-01

442

Characterization of the antigenicity of Cpl1, a surface protein of Cryptococcus neoformans var. neoformans.  

PubMed

Cryptococcus neoformans var. neoformans is an important fungal pathogen. The capsule is a well established virulence factor and a target site for diagnostic tests. The CPL1 gene is required for capsular formation and virulence. The protein product Cpl1 has been proposed to be a secreted protein, but the characteristics of this protein have not been reported. Here we sought to characterize Cpl1. Phylogenetic analysis showed that the Cpl1 of C. neoformans var. neoformans and the Cpl1 orthologs identified in C. neoformans var. grubii and C. gattii formed a distinct cluster among related fungi; while the putative ortholog found in Trichosporon asahii was distantly related to the Cryptococcus cluster. We expressed Cpl1 abundantly as a secreted His-tagged protein in Pichia pastoris. The protein was used to immunize guinea pigs and rabbits for high titer mono-specific polyclonal antibody that was shown to be highly specific against the cell wall of C. neoformans var. neoformans and did not cross react with C. gattii, T. asahii, Aspergillus spp., Candida spp. and Penicillium spp. Using the anti-Cpl1 antibody, we detected Cpl1 protein in the fresh culture supernatant of C. neoformans var. neoformans and we showed by immunostaining that the Cpl1 protein was located on the surface. The Cpl1 protein is a specific surface protein of C. neoformans var. neoformans. PMID:25261494

Cai, Jian-Piao; Liu, Ling-Li; To, Kelvin K W; Lau, Candy C Y; Woo, Patrick C Y; Lau, Susanna K P; Guo, Yong-Hui; Ngan, Antonio H Y; Che, Xiao-Yan; Yuen, Kwok-Yung

2015-01-01

443

Semi-nonparametric VaR forecasts for hedge funds during the recent crisis  

NASA Astrophysics Data System (ADS)

The need to provide accurate value-at-risk (VaR) forecasting measures has triggered an important literature in econophysics. Although these accurate VaR models and methodologies are particularly demanded for hedge fund managers, there exist few articles specifically devoted to implement new techniques in hedge fund returns VaR forecasting. This article advances in these issues by comparing the performance of risk measures based on parametric distributions (the normal, Student’s t and skewed-t), semi-nonparametric (SNP) methodologies based on Gram-Charlier (GC) series and the extreme value theory (EVT) approach. Our results show that normal-, Student’s t- and Skewed t- based methodologies fail to forecast hedge fund VaR, whilst SNP and EVT approaches accurately success on it. We extend these results to the multivariate framework by providing an explicit formula for the GC copula and its density that encompasses the Gaussian copula and accounts for non-linear dependences. We show that the VaR obtained by the meta GC accurately captures portfolio risk and outperforms regulatory VaR estimates obtained through the meta Gaussian and Student’s t distributions.

Del Brio, Esther B.; Mora-Valencia, Andrés; Perote, Javier

2014-05-01

444

Arundina graminifolia var. revoluta (Arethuseae, Orchidaceae) has fern-type rheophyte characteristics in the leaves.  

PubMed

Morphological and molecular variation between Arundina graminifolia var. graminifolia and the dwarf variety, A. graminifolia var. revoluta, was examined to assess the validity of their taxonomic characteristics and genetic background for identification. Morphological analysis in combination with field observations indicated that A. graminifolia var. revoluta is a rheophyte form of A. graminifolia characterized by narrow leaves, whereas the other morphological characteristics described for A. graminifolia var. revoluta, such as smaller flowers and short stems, were not always accompanied by the narrower leaf phenotype. Molecular analysis based on matK sequences indicated that only partial differentiation has occurred between A. graminifolia var. graminifolia and A. graminifolia var. revoluta. Therefore, we should consider the rheophyte form an ecotype rather than a variety. Anatomical observations of the leaves revealed that the rheophyte form of A. graminifolia possessed characteristics of the rheophytes of both ferns and angiosperms, such as narrower palisade tissue cells and thinner spongy tissue cells, as well as fewer cells in the leaf-width direction and fewer mesophyll cell layers. PMID:25502073

Yorifuji, Eri; Ishikawa, Naoko; Okada, Hiroshi; Tsukaya, Hirokazu

2015-03-01

445

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

446

A P-glycoprotein protects Caenorhabditis elegans against natural toxins.  

PubMed Central

P-glycoproteins can cause resistance of mammalian tumor cells to chemotherapeutic drugs. They belong to an evolutionarily well-conserved family of ATP binding membrane transporters. Four P-glycoprotein gene homologs have been found in the nematode Caenorhabditis elegans; this report describes the functional analysis of two. We found that PGP-3 is expressed in both the apical membrane of the excretory cell and in the apical membrane of intestinal cells, whereas PGP-1 is expressed only in the apical membrane of the intestinal cells and the intestinal valve. By transposon-mediated deletion mutagenesis we generated nematode strains with deleted P-glycoprotein genes and found that the pgp-3 deletion mutant, but not the pgp-1 mutant, is sensitive to both colchicine and chloroquine. Our results suggest that soil nematodes have P-glycoproteins to protect themselves against toxic compounds made by plants and microbes in the rhizosphere. Images PMID:7743993

Broeks, A; Janssen, H W; Calafat, J; Plasterk, R H

1995-01-01

447

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

448

C. elegans Nuclear Receptors: Insights into Life Traits  

PubMed Central

Nuclear receptors (NRs) are a class of hormone-gated transcription factors found in metazoans that regulate global changes in gene expression when bound to their cognate ligands. Despite species diversification, NRs act similarly across taxa to play fundamental roles in detecting intrinsic and environmental signals, and subsequently in coordinating transcriptional cascades that direct reproduction, development, metabolism, and homeostasis. These endocrine receptors function in vivo in part as molecular switches and timers that regulate transcriptional cascades. Here we discuss in detail how several C. elegans NRs integrate intrinsic and extrinsic signals to regulate the dauer diapause and longevity, molting, and heterochronic circuits of development, and draw parallels to similar in vivo endocrine regulated processes in other animals. PMID:18406164

Magner, Daniel B.; Antebi, Adam

2009-01-01

449

CED-9 and mitochondrial homeostasis in C. elegans muscle  

PubMed Central

Summary Mitochondrial homeostasis reflects a dynamic balance between membrane fission and fusion events thought essential for mitochondrial function. We report here that altered expression of the C. elegans BCL2 homolog CED-9 affects both mitochondrial fission and fusion. Although striated muscle cells lacking CED-9 have no alteration in mitochondrial size or ultrastructure, these cells appear more sensitive to mitochondrial fragmentation. By contrast, increased CED-9 expression in these cells produces highly interconnected mitochondria. This mitochondrial phenotype is partially suppressed by increased expression of the dynamin-related GTPase DRP-1, with suppression dependent on the BH3 binding pocket of CED-9. This suppression suggests that CED-9 directly regulates DRP-1, a model supported by our finding that CED-9 activates the GTPase activity of human DRP1. Thus, CED-9 is capable of regulating the mitochondrial fission-fusion cycle but is not essential for either fission or fusion. PMID:18827010

Tan, Frederick J.; Husain, Michelle; Manlandro, Cara Marie; Koppenol, Marijke; Fire, Andrew Z.; Hill, R. Blake

2009-01-01

450

Edgetic perturbation of a C. elegans BCL2 ortholog  

PubMed Central

Genes and gene products do not function in isolation but within highly interconnected “interactome” networks, modeled as graphs of nodes and edges representing macromolecules and interactions between them, respectively. We propose to investigate genotype-phenotype associations by methodical use of alleles that lack single interactions, while retaining all others, in contrast to genetic approaches designed to eliminate gene products completely. We describe an integrated strategy based on the reverse yeast two-hybrid system to isolate and characterize such edge-specific, or “edgetic” alleles. We establish a proof-of-concept with CED-9, a C. elegans BCL2 ortholog involved in apoptosis. Using ced-9 edgetic alleles, we uncover a new potential functional link between apoptosis and a centrosomal protein, demonstrating both the interest and efficiency of our strategy. This approach is amenable to higher throughput and is particularly applicable to interactome network analysis in organisms for which transgenesis is straightforward. PMID:19855391

Dreze, Matija; Charloteaux, Benoit; Milstein, Stuart; Vidalain, Pierre-Olivier; Yildirim, Muhammed A; Zhong, Quan; Svrzikapa, Nenad; Romero, Viviana; Laloux, Géraldine; Brasseur, Robert; Vandenhaute, Jean; Boxem, Mike; Cusick, Michael E; Hill, David E; Vidal, Marc

2010-01-01

451

Natural and Unanticipated Modifiers of RNAi Activity in Caenorhabditis elegans  

E-print Network

the rde-1(yy11) insertion, yielding an ampli- fication product of 279 bp. dsRNA delivery by ‘‘feeding’’ Standard C. elegans plates supplemented with cholesterol, ampicillin, tetracycline, and IPTG were seeded with the Escherichia coli strain HT115(DE3...(e245) dpy-4(e1166)] IV, PD9064 [dpy-11(e224) unc-60(e723)] V: pPD4300 [ccIs4251 (myo- 3::GFP) I; ayIs2 (egl-15::GFP) IV; ayIs6 (hlh-8::GFP) X]; pPD5063 [ccIs4251 (myo-3::GFP) I]; PD8175 [rde-1(ne219)]. Deletion strains used to map rde-4(ne309) (from...

Asad, Nadeem; Yih Aw, Wen; Timmons, Lisa

2012-11-28

452

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

PubMed

The knowledge on Odonata adult mouthparts sensilla is scanty and, notwithstanding the epipharynx in the labrum is considered an organ of taste, no ultrastructural investigation has been performed so far on this structure in Odonata. The labrum of the adult of the damselfly Ischnura elegans (Odonata, Coenagrionidae) shows on its ventral side the epipharynx with sensilla represented by articulated hairs and by small pegs located at the apex of slightly raised domes. Under scanning and transmission electron microscope, the articulated hairs, with a well developed socket and tubular body, have the typical structure of bristles, the most common type of insect mechanoreceptors, usually responding to direct touch; the pegs, showing an apical pore together with a variable number of sensory neurons (from two to five), the outer dendritic segments of which show a dendrite sheath stopping along their length, have features typical of contact chemoreceptors. PMID:25080274

Rebora, Manuela; Gaino, Elda; Piersanti, Silvana

2014-11-01

453

Investigating the Role of RIO Protein Kinases in Caenorhabditis elegans  

PubMed Central

RIO protein kinases (RIOKs) are a relatively conserved family of enzymes implicated in cell cycle control and ribosomal RNA processing. Despite their functional importance, they remain a poorly understood group of kinases in multicellular organisms. Here, we show that the C. elegans genome contains one member of each of the three RIOK sub-families and that each of the genes coding for them has a unique tissue expression pattern. Our analysis showed that the gene encoding RIOK-1 (riok-1) was broadly and strongly expressed. Interestingly, the intestinal expression of riok-1 was dependent upon two putative binding sites for the oxidative and xenobiotic stress response transcription factor SKN-1. RNA interference (RNAi)-mediated knock down of riok-1 resulted in germline defects, including defects in germ line stem cell proliferation, oocyte maturation and the production of endomitotic oocytes. Taken together, our findings indicate new functions for RIOK-1 in post mitotic tissues and in reproduction. PMID:25688864

Raymant, Greta; Bertram, Sonja E.; Esmaillie, Reza; Nadarajan, Saravanapriah; Breugelmans, Bert; Hofmann, Andreas; Gasser, Robin B.; Colaiácovo, Monica P.; Boag, Peter R.

2015-01-01

454

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

455

Iron promotes protein insolubility and aging in C. elegans  

PubMed Central

Many late-onset proteotoxic diseases are accompanied by a disruption in homeostasis of metals (metallostasis) including iron, copper and zinc. Although aging is the most prominent risk factor for these disorders, the impact of aging on metallostasis and its role in proteotoxic disease remain poorly understood. Moreover, it is not clear whether a loss of metallostasis influences normal aging. We have investigated the role of metallostasis in longevity of Caenorhabditis elegans. We found that calcium, copper, iron, and manganese levels increase as a function of age, while potassium and phosphorus levels tend to decrease. Increased dietary iron significantly accelerated the age-related accumulation of insoluble protein, a molecular pathology of aging. Proteomic analysis revealed widespread effects of dietary iron in multiple organelles and tissues. Pharmacological interventions to block accumulation of specific metals attenuated many models of proteotoxicity and extended normal lifespan. Collectively, these results suggest that a loss of metallostasis with aging contributes to age-related protein aggregation. PMID:25554795

Klang, Ida M.; Schilling, Birgit; Sorensen, Dylan J.; Sahu, Alexandria K.; Kapahi, Pankaj; Andersen, Julie K.; Swoboda, Peter; Killilea, David W.; Gibson, Bradford W.; Lithgow, Gordon J.

2014-01-01

456

How Does C. elegans Respond to Altered Gravity?  

NASA Technical Reports Server (NTRS)

All organisms on Earth have evolved at unit gravity (1xG), and thus are probably adapted to function optimally at 1xG. However, with the advent of space exploration, it has been shown that organisms are capable of surviving at much less than 1xG, as well as at greater than 1xG. Organisms subjected to increased G levels exhibit alterations in physiological processes that compensate for novel environmental stresses, such as increased weight and density-driven sedimentation. These physiological adaptations illustrate the plasticity of organisms when presented with environmental conditions in which they could not possibly have evolved. Investigating the mechanism(s) behind these adaptations may uncover biological pathways that have not previously been identified. An easily-cultured and well-studied organism, such as C. elegans, would be a desirable model system for these studies. Additional information is contained in the original extended abstract.

Conley, Catharine A.; Udranszky, Ingrid; Hoffman, David; Kim, Stuart K.

2001-01-01

457

TOR signaling couples oxygen sensing to lifespan in C. elegans  

PubMed Central

Summary Metazoans adapt to a low oxygen environment (hypoxia) through activation of stress response pathways. Here we report that transient hypoxia exposure extends lifespan in C. elegans through mitochondrial ROS-dependent regulation of the nutrient sensing kinase TOR and its upstream activator RHEB-1. The increase in lifespan during hypoxia requires the intestinal GATA-type transcription factor, ELT-2, downstream of TOR signaling. Using RNA-Sequencing, we describe an ELT-2-dependent hypoxia response that includes an intestinal glutathione S-transferase, GSTO-1, and uncover that GSTO-1 is required for lifespan under hypoxia. These results indicate mitochondrial ROS-dependent TOR signaling integrates metabolic adaptations to confer survival under hypoxia. PMID:25284791

Schieber, Michael; Chandel, Navdeep S.

2014-01-01

458

Mechanical systems biology of C. elegans touch sensation.  

PubMed

The sense of touch informs us of the physical properties of our surroundings and is a critical aspect of communication. Before touches are perceived, mechanical signals are transmitted quickly and reliably from the skin's surface to mechano-electrical transduction channels embedded within specialized sensory neurons. We are just beginning to understand how soft tissues participate in force transmission and how they are deformed. Here, we review empirical and theoretical studies of single molecules and molecular ensembles thought to be involved in mechanotransmission and apply the concepts emerging from this work to the sense of touch. We focus on the nematode Caenorhabditis elegans as a well-studied model for touch sensation in which mechanics can be studied on the molecular, cellular, and systems level. Finally, we conclude that force transmission is an emergent property of macromolecular cellular structures that mutually stabilize one another. PMID:25597279

Krieg, Michael; Dunn, Alexander R; Goodman, Miriam B

2015-03-01

459

Alternative meiotic chromatid segregation in the holocentric plant Luzula elegans.  

PubMed

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

460

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

461

Suppressors of the Unc-73 Gene of Caenorhabditis Elegans  

PubMed Central

The unc-73 gene of Caenorhabditis elegans is necessary for proper axon guidance. Animals mutant in this gene are severely uncoordinated and also exhibit defects in cell migration and cell lineages. We have isolated coordinated revertants of unc-73(e936). These fall into three classes: intragenic revertants, extragenic dominant suppressors (sup-39), and a single apparently intragenic mutation that is a dominant suppressor with a linked recessive lethal phenotype. sup-39 mutations cause early embryonic lethality, but escapers have a wild-type movement phenotype as larvae and adults. Gonads of sup-39 mutant animals show a novel defect: normal gonads have a single row of oocytes, but sup-39 gonads often have two rows of oocytes. This result suggests that the mutant gonad is defective in choosing on its surface only a single site from which nuclei will emerge to form oocytes. These results are interpreted in terms of an effect of unc-73 on determination of cell polarity. PMID:8722777

Run, J. Q.; Steven, R.; Hung, M. S.; van-Weeghel, R.; Culotti, J. G.; Way, J. C.

1996-01-01

462

Behavioral degradation under mutation accumulation in Caenorhabditis elegans.  

PubMed

Spontaneous mutations play a fundamental role in the maintenance of genetic variation in natural populations, the nature of inbreeding depression, the evolution of sexual reproduction, and the conservation of endangered species. Using long-term mutation-accumulation lines of the nematode Caenorhabditis elegans, we estimate the rate and magnitude of mutational effects for a suite of behaviors characterizing individual chemosensory responses to a repellant stimulus. In accordance with evidence that the vast majority of mutations are deleterious, we find that behavioral responses degrade over time as a result of spontaneous mutation accumulation. The rate of mutation for behavioral traits is roughly of the same order or slightly smaller than those previously estimated for reproductive traits and the average size of the mutational effects is also comparable. These results have important implications for the maintenance of genetic variation for behavior in natural populations as well as for expectations for behavioral change within endangered species and captive populations. PMID:15834141

Ajie, Beverly C; Estes, Suzanne; Lynch, Michael; Phillips, Patrick C

2005-06-01

463

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

464

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

2014-01-01

465

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

466

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

467

ceh-16/engrailed patterns the embryonic epidermis of Caenorhabditis elegans.  

PubMed

engrailed is a homeobox gene essential for developmental functions such as differentiation of cell populations and the onset of compartment boundaries in arthropods and vertebrates. We present the first functional study on engrailed in an unsegmented animal: the nematode Caenorhabditis elegans. In the developing worm embryo, ceh-16/engrailed is predominantly expressed in one bilateral row of epidermal cells (the seam cells). We show that ceh-16/engrailed primes a specification cascade through three mechanisms: (1) it suppresses fusion between seam cells and other epidermal cells by repressing eff-1/fusogen expression; (2) it triggers the differentiation of the seam cells through different factors, including the GATA factor elt-5; and (3) it segregates the seam cells into a distinct lateral cellular compartment, repressing cell migration toward dorsal and ventral compartments. PMID:15659483

Cassata, Giuseppe; Shemer, Gidi; Morandi, Paolo; Donhauser, Roland; Podbilewicz, Benjamin; Baumeister, Ralf

2005-02-01

468

A spatial and temporal map of C. elegans gene expression  

PubMed Central

The C. elegans genome has been completely sequenced, and the developmental anatomy of this model organism is described at single-cell resolution. Here we utilize strategies that exploit this precisely defined architecture to link gene expression to cell type. We obtained RNAs from specific cells and from each developmental stage using tissue-specific promoters to mark cells for isolation by FACS or for mRNA extraction by the mRNA-tagging method. We then generated gene expression profiles of more than 30 different cells and developmental stages using tiling arrays. Machine-learning–based analysis detected transcripts corresponding to established gene models and revealed novel transcriptionally active regions (TARs) in noncoding domains that comprise at least 10% of the total C. elegans genome. Our results show that about 75% of transcripts with detectable expression are differentially expressed among developmental stages and across cell types. Examination of known tissue- and cell-specific transcripts validates these data sets and suggests that newly identified TARs may exercise cell-specific functions. Additionally, we used self-organizing maps to define groups of coregulated transcripts and applied regulatory element analysis to identify known transcription factor– and miRNA-binding sites, as well as novel motifs that likely function to control subsets of these genes. By using cell-specific, whole-genome profiling strategies, we have detected a large number of novel transcripts and produced high-resolution gene expression maps that provide a basis for establishing the roles of individual genes in cellular differentiation. PMID:21177967

Spencer, W. Clay; Zeller, Georg; Watson, Joseph D.; Henz, Stefan R.; Watkins, Kathie L.; McWhirter, Rebecca D.; Petersen, Sarah; Sreedharan, Vipin T.; Widmer, Christian; Jo, Jeanyoung; Reinke, Valerie; Petrella, Lisa; Strome, Susan; Von Stetina, Stephen E.; Katz, Menachem; Shaham, Shai; Rätsch, Gunnar; Miller, David M.

2011-01-01

469

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

470

Isoflurane Selectively Inhibits Distal Mitochondrial Complex I in Caenorhabditis Elegans  

PubMed Central

BACKGROUND Complex I of the electron transport chain (ETC) is a possible target of volatile anesthetics (VAs). Complex I enzymatic activities are inhibited by VAs, and dysfunction of complex I can lead to hypersensitivity to VAs in worms and in people. Mutant analysis in Caenorhabditis (C.) elegans suggests that VAs may specifically interfere with complex I function at the binding site for its substrate ubiquinone. We hypothesized that isoflurane inhibits electron transport by competing with ubiquinone for binding to complex I. METHODS Wildtype and mutant C. elegans were used to study the effects of isoflurane on isolated mitochondria. Enzymatic activities of the ETC were assayed and dose-response curves determined using established techniques. Two-dimensional native gels of mitochondrial proteins were performed after exposure of mitochondria to isoflurane. RESULTS Complex I is the most sensitive component of the ETC to isoflurane inhibition; however the proximal portion of complex I (the flavoprotein) is relatively insensitive to isoflurane. Isoflurane and quinone do not compete for a common binding site on complex I. The absolute rate of complex I enzymatic activity in vitro does not predict immobilization of the animal by isoflurane. Isoflurane had no measurable effect on stability of mitochondrial supercomplexes. Reduction of ubiquinone by complex I displayed positive cooperative kinetics not disrupted by isoflurane. CONCLUSIONS Isoflurane directly inhibits complex I at a site distal to the flavoprotein subcomplex. However, we have excluded our original hypothesis that isoflurane and ubiquinone compete for a common hydrophobic binding site on complex I. In addition, immobilization of the nematode by isoflurane is not due to limiting absolute amounts of complex I electron transport as measured in isolated mitochondria. PMID:21467554

Kayser, Ernst-Bernhard; Suthammarak, Wichit; Morgan, Phil G.; Sedensky, Margaret M.

2011-01-01

471

A transcribed polyketide synthase gene from Xanthoria elegans.  

PubMed

We characterize the transcript of a polyketide synthase gene (PKS) from the cultured mycobiont of Xanthoria elegans (XePKS1) using SMART-rapid amplification of cDNA ends (RACE) cDNA synthesis. Sequence analysis of the cloned cDNA reveals an open reading frame of 2144 amino acid residues. It contains features of a non-reducing fungal type I PKS with an N-terminal starter unit: acyl carrier protein (ACP) transacetylase domain, ketosynthase, acyltransferase, two acyl carrier protein domains, and a thioesterase domain. XePKS1 was the only paralogue detected in the cDNA and the genomic DNA of the cultured X. elegans mycobiont by using a degenerate PCR approach targeted at the conserved regions of non-reducing type I PKS genes. The hypothetical protein is phylogenetically related to genes that are basal to a clade of dihydroxynaphthalene synthases (non-reducing clade II) and anthraquinone type synthases of non-lichenized fungi (non-reducing clade I). According to hplc and tlc analyses, the cultured mycobiont exclusively produced anthraquinones and its precursors. Therefore, we discuss whether the characterized paralogue is involved in anthraquinone production, which raises the possibility of a paraphyletic origin of lichen anthraquinone biosynthesis. The cDNA of XePKS1 was the first full-length coding sequence of a lichen PKS to be published. This proves SMART RACE to be a suitable tool for obtaining full-length coding sequences of genes from environmental samples and organisms, which are hardly amenable to standard molecular approaches or genomic sequencing. PMID:18822374

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

2009-01-01

472

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

473

Genome-wide analysis of condensin binding in Caenorhabditis elegans  

PubMed Central

Background Condensins are multi-subunit protein complexes that are essential for chromosome condensation during mitosis and meiosis, and play key roles in transcription regulation during interphase. Metazoans contain two condensins, I and II, which perform different functions and localize to different chromosomal regions. Caenorhabditis elegans contains a third condensin, IDC, that is targeted to and represses transcription of the X chromosome for dosage compensation. Results To understand condensin binding and function, we performed ChIP-seq analysis of C. elegans condensins in mixed developmental stage embryos, which contain predominantly interphase nuclei. Condensins bind to a subset of active promoters, tRNA genes and putative enhancers. Expression analysis in kle-2-mutant larvae suggests that the primary effect of condensin II on transcription is repression. A DNA sequence motif, GCGC, is enriched at condensin II binding sites. A sequence extension of this core motif, AGGG, creates the condensin IDC motif. In addition to differences in recruitment that result in X-enrichment of condensin IDC and condensin II binding to all chromosomes, we provide evidence for a shared recruitment mechanism, as condensin IDC recruiter SDC-2 also recruits condensin II to the condensin IDC recruitment sites on the X. In addition, we found that condensin sites overlap extensively with the cohesin loader SCC-2, and that SDC-2 also recruits SCC-2 to the condensin IDC recruitment sites. Conclusions Our results provide the first genome-wide view of metazoan condensin II binding in interphase, define putative recruitment motifs, and illustrate shared loading mechanisms for condensin IDC and condensin II. PMID:24125077

2013-01-01

474

Mechanisms of plasticity in a Caenorhabditis elegans mechanosensory circuit  

PubMed Central

Despite having a small nervous system (302 neurons) and relatively short lifespan (14–21 days), the nematode Caenorhabditis elegans has a substantial ability to change its behavior in response to experience. The behavior discussed here is the tap withdrawal response, whereby the worm crawls backwards a brief distance in response to a non-localized mechanosensory stimulus from a tap to the side of the Petri plate within which it lives. The neural circuit that underlies this behavior is primarily made up of five sensory neurons and four pairs of interneurons. In this review we describe two classes of mechanosensory plasticity: adult learning and memory and experience dependent changes during development. As worms develop through young adult and adult stages there is a shift toward deeper habituation of response probability that is likely the result of changes in sensitivity to stimulus intensity. Adult worms show short- intermediate- and long-term habituation as well as context dependent habituation. Short-term habituation requires glutamate signaling and auto-phosphorylation of voltage-dependent potassium channels and is modulated by dopamine signaling in the mechanosensory neurons. Long-term memory (LTM) for habituation is mediated by down-regulation of expression of an AMPA-type glutamate receptor subunit. Intermediate memory involves an increase in release of an inhibitory neuropeptide. Depriving larval worms of mechanosensory stimulation early in development leads to fewer synaptic vesicles in the mechanosensory neurons and lower levels of an AMPA-type glutamate receptor subunit in the interneurons. Overall, the mechanosensory system of C. elegans shows a great deal of experience dependent plasticity both during development and as an adult. The simplest form of learning, habituation, is not so simple and is mediated and/or modulated by a number of different processes, some of which we are beginning to understand. PMID:23986713

Bozorgmehr, Tahereh; Ardiel, Evan L.; McEwan, Andrea H.; Rankin, Catharine H.

2012-01-01

475

Diverse roles of actin in C. elegans early embryogenesis  

PubMed Central

Background The actin cytoskeleton plays critical roles in early development in Caenorhabditis elegans. To further understand the complex roles of actin in early embryogenesis we use RNAi and in vivo imaging of filamentous actin (F-actin) dynamics. Results Using RNAi, we found processes that are differentially sensitive to levels of actin during early embryogenesis. Mild actin depletion shows defects in cortical ruffling, pseudocleavage, and establishment of polarity, while more severe depletion shows defects in polar body extrusion, cytokinesis, chromosome segregation, and eventually, egg production. These defects indicate that actin is required for proper oocyte development, fertilization, and a wide range of important events during early embryogenesis, including proper chromosome segregation. In vivo visualization of the cortical actin cytoskeleton shows dynamics that parallel but are distinct from the previously described myosin dynamics. Two distinct types of actin organization are observed at the cortex. During asymmetric polarization to the anterior, or the establishment phase (Phase I), actin forms a meshwork of microfilaments and focal accumulations throughout the cortex, while during the anterior maintenance phase (Phase II) it undergoes a morphological transition to asymmetrically localized puncta. The proper asymmetric redistribution is dependent on the PAR proteins, while both asymmetric redistribution and morphological transitions are dependent upon PFN-1 and NMY-2. Just before cytokinesis, actin disappears from most of the cortex and is only found around the presumptive cytokinetic furrow. Finally, we describe dynamic actin-enriched comets in the early embryo. Conclusion During early C. elegans embryogenesis actin plays more roles and its organization is more dynamic than previously described. Morphological transitions of F-actin, from meshwork to puncta, as well as asymmetric redistribution, are regulated by the PAR proteins. Results from this study indicate new insights into the cellular and developmental roles of the actin cytoskeleton. PMID:18157918

Velarde, Nathalie; Gunsalus, Kristin C; Piano, Fabio

2007-01-01

476

In vitro propagation of Dioscorea alata var. purpurae.  

PubMed

Dioscorea alata var. purpurae (Indian purple yam) is an important source of diosgenin, a triterpenoid that is used as a raw material in the synthesis of corticosteroid hormones. These drugs are used for the treatment of pharmacological conditions such as arthritis. This paper reports in vitro propagation of explants of various parts of Dioscorea-tuber, leaves, and nodes. Murashige and Skoog media supplemented with hormones and additives was used to get maximum callus initiation and shoot/root induction. All the cultures were maintained at 25?±?2 °C under cool-white fluorescent tubes with 16-h photoperiod. Callus initiation was observed from 8th to 11th day of inoculation, and subsequent root/shoot was initiated in nodal callus after 21 days. Hormones such as kinetin, indole-3-acetic acid, indole-3-butyric acid, ?-naphthalene acetic acid, and thiadizuron did not show significant enhancement. Also, there was no need for supplementing additives (silver nitrate, glutamine, L-: asparagine monohydrate, polyethylene glycol). Combination of 6-benzylaminopurine (0.2 ppm) and 2,4-dichlorophenoxyacetic acid (2 ppm) hormones gave the best results, and all parts of the plants gave similar callus induction. PMID:22476929

Shah, Heena J; Lele, S S

2012-07-01

477

Chemical constituents of the rhizomes of Coeloglossum viride var. bracteatum.  

PubMed

Seven new compounds, named coelovirins A-G (1-7), along with fourteen known constituents were isolated from the rhizomes of Coeloglossom viride var. bracteatum (Orchidaceae). On the basis of chemical and spectroscopic methods, including 2D-NMR techniques, the structures of new compounds were elucidated as 1-(4-beta-D-glucopyranosyloxybenzyl)-(2R,3S)-2-isobutyltartrate (1), 4-(4-beta-glucopyranosyloxybenzyl)-(2R,3S)-2-isobutyltartrate (2), 1-(4-beta-D-glucopyranosyloxybenzyl)-(2R,3S)-2-beta-D-glucopyranosyl-2-isobutyltartrate (3), 4-(4-beta-D-glucopyranosyloxybenzyl)-(2R,3S)-2-beta-D-glucopyranosyl-2-isobutyltartrate (4), (2R,3S)-2-beta-D-glucopyranosyl-2-isobutyltartaric acid (5), bis(4-beta-D-glucopyranosyloxybenzyl)-(2R,3S)-2-[beta-D-glucopyranosyl-(1 --> 4)-beta-D-glucopyranosyl]-2-isobutyltartrate (6) and bis(4-beta-D-glucopyranosyloxybenzyl)-(2R)-2-[beta-D-glucopyranosyl-(1 --> 4)-beta-D-glucopyranosyl]-2-isobutylmalate (7). The known compounds are 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol, 4,4'-dihydroxydibenzyl ether, 4,4'-dihydroxydiphenylmethane, 4-(4-hydroxybenzyloxy)benzyl alcohol, gastrodin, quercetin-3,7-diglucoside, thymidine, loroglossin, militarine, dactylorhin A, dactylorhin B, beta-sitosterol and daucosterol. PMID:14989381

Huang, Sheng-Yang; Li, Guo-Qiang; Shi, Jian-Gong; Mo, Shun-Yan

2004-03-01

478

Acylated iridoids from the roots of Valeriana officinalis var. latifolia.  

PubMed

Phytochemical investigation of the roots of Valeriana officinalis var. latifolia resulted in the isolation and characterization of six new acylated iridoids, (5S,7S,8S,9S)-7-hydroxy-8-isovaleroyloxy-??,¹¹-dihyronepetalactone (1), (5S,7S,8S,9S)-7-hydroxy-10-isovaleroyloxy-??,¹¹-dihyronepetalactone (2), (5S,8S,9S)-10-isovaleroyloxy-??,¹¹-dihyronepetalactone (3), (5S,6S,8S,9R)-6-isovaleroyloxy-??,¹¹-1,3-diol (4), (5S,6S,8S,9R)-1,3-isovaleroxy-?4,11-1,3-diol (5), and (5S,6S,8S,9R)-3-isovaleroxy-6-isovaleroyloxy-??,¹¹-1,3-diol (6). Their structures were determined mainly by 1D and 2D?NMR spectroscopic techniques. We also report herein for the first time the single crystal X-ray structure of compound 1. In addition, the cytotoxic activities of compounds 1-6 were evaluated against A549 (human lung adenocarcinoma), HCT116 (human colon carcinoma), SK-BR-3 (human breast carcinoma), and HepG2 (human hepatoma) cell lines. Compound 6 showed weak cell growth inhibition of A549, HCT116, SK-BR-3, and HepG2 cells. PMID:22872588

Han, Zhu-zhen; Yan, Zhao-hui; Liu, Qing-xin; Hu, Xian-qing; Ye, Ji; Li, Hui-liang; Zhang, Wei-dong

2012-10-01

479