Directory. Start here to access encyclopedic information about the worm genome and its genes, proteins, and other encoded features… Find out more. ...
1. Baldwin, J.G., Nadler, S.A., and Wall, D.H. 1997. Nematodes: Pervading the Earth and Linking all Life. Pp. 176-191. In: Raven, P.H. (ed.). National Academy Press, Washington, D.C. 625 pp.. 2. Bargmann, C. I. 1998. Neurobiology of the Caenorhabditis elegans genome. Science 282:2028-2033.. 3. Bargmann, C. I. And Mori, I. 1997. Chemotaxis and Thermotaxis. Pp. 717-737. In: Riddle, D.L., Blumenthal, T., Meyer, B.J. and Priess, J.R. (eds). C. elegans II. Cold Spring Harbor Laboratory Press, Plainview, NY 1222 pp.. 4. Bird, D.M. and Opperman, C. H. 1998. Caenorhabditis elegans. J. Nematol. 30:299-308.. 5. Bird, D.M., Opperman, C.H., Jones S.J.M., and Baillie, D.L. 1999. The Caenorhabditis elegans gemome: a guide in the post genomics age. Annu. Rev. Phytopathol. 37:247-265.. 6. Blaxter, M. 1998. Caenorhabditis elegans is a nematode. Science 282:2041-2046.. 7. Blaxter, M. and Bird, D. 1997. Parasitic nematodes. Pp. 851-878. In: Riddle, D.L., Blumenthal, T., Meyer, B.J. and Priess, J.R. (eds). C. ...
Mutations in the gene unc-53 of Caenorhabditis elegans result in behavioral and anatomical abnormalities. Immunocytochemistry and electron microscopy revealed neuroanatomical defects in all main longitudinal nervous tracts. Whole tracts were found to
TY - JOUR. T1 - The novel C. elegans gene sop-3 modulates Wnt signaling to regulate Hox gene expression. AU - Zhang, H.. AU - Emmons, S. W.. PY - 2001/4/2. Y1 - 2001/4/2. N2 - We describe the properties of a new gene, sop-3, that is required for the regulated expression of a C. elegans Hox gene, egl-5, in a postembryonic neuroectodermal cell lineage. Regulated expression of egl-5 in this cell lineage is necessary for development of the sensory rays of the male tail. sop-3 encodes a predicted novel protein of 1475 amino acids without clear homologs in other organisms. However, the sequence contains motifs consisting of homopolymeric runs of amino acids found in several other transcriptional regulators, some of which also act in Hox gene regulatory pathways. The genetic properties of sop-3 are very similar to those of sop-1, which encodes a component of the transcriptional Mediator complex, and mutations in the two genes are synthetic lethal. This suggests that SOP-3 may act at the level of the ...
There are two likely explanations for the greater success of the GFP screen. First, nearly half of the mutants isolated in the direct screen were less than 10% Wit or Clr and would have been missed in the Wit and Clr screen. Second, several of the mutants developed slowly. The Wit phenotype is most easily scored in adult animals, while defects visualized by GFP could be scored in younger animals. In the Wit and Clr screen, mutants that are slow to reach adulthood might be lost among the next generation of nonmutant animals.. Three Syc mutants require the presence of kyIs5 to express the Cam phenotype: mutations in the syc genes result in defects in CAN cell migration only when kyIs5 is present (Figure 4). Mutations in each of the Syc genes results in weak (syc-1 and syc-3) or strong (syc-2) Unc phenotypes in the absence of the transgene, suggesting that the mutations disrupt the development or function of additional neurons. The effects on CAN migration are enhanced when the syc-3 mutation is ...
A one-millimeter worm, the nematode Caenorhabditis elegans, is an animal model widely used in biomedical research by hundreds of laboratories around the world. Surprisingly, it has approximately the same number of genes that humans have, about 20,000. In addition, most human disease-causing genes have their counterparts, or orthologs, in C. elegans worms.. Thus, for example, the human SF3B1 gene, which is mutated in different types of cancers, mainly in leukemia but also in some breast or prostate tumors, is very similar to the sftb-1 gene of C. elegans worms. In fact, 89 percent of the amino acid sequence of the human SF3B1 protein in its most cancer-affected region are identical. Some of these amino acids are conserved from worms to humans, including those that are mutated in some tumors.. A group of researchers led by Dr. Julián Cerón of the Bellvitge Biomedical Research Institute (IDIBELL), has taken advantage of the similarity between these amino acids and their experience in CRISPR gene ...
JVCC PES-32G Polyester Film Packaging Tape is a heavy-duty polyester film packaging tape used to meet the highest of quality & performance requirements. Meets PPP-T-60E Type 3 federal specification. Rank #28 in Sale & Overstock Items category.
The nematode embryo is an ideal system in which to explore the genetic encoding of biomechanical information of this type. The oval-shaped embryo of the nematode Caenorhaditis elegans forms an elongate worm using the principle of the fiber-wound, pressurized cylinder, but, in this case, the pressure is generated by the circumferential contraction of a cytoskeleton, an event that is preceded by cell movements that form a circumferentially reinforced array of cells that develop this contractile force. The hypodermal cells (also called epidermal cells) initially lie dorsally in three rows per side, which are named the dorsal, lateral and ventral hypodermal cells from their eventual position (Priess and Hirsh, 1986; Simske and Hardin, 2001) (see Fig. 2A,D,G). First, the two rows of dorsal cells intercalate to form a narrower but longer single row (see Fig. 2A-C), which elongates the dorsum of the embryo, and gives it a convex dorsal curvature and a concave ventral curvature (Priess and Hirsh, 1986) ...
Hi,. I am a student who is looking to express the ACTG1 gene is c. elegans....how would i go about finding a method to see if the gene has successfully been transformed into the c. elegans.. ...
Bayesian length-weight: a=0.00324 (0.00121 - 0.00866), b=3.08 (2.84 - 3.32), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245 ...
Mouse mAb M38 was used in indirect immunofluorescence experiments to detect a stage-specific antigen on the surface of the first larval stage (L1) of the free-living nematode Caenorhabditis elegans, and to detect alterations in the apparent expression of this antigen in two distinct classes of C. elegans mutants. In previously described srf-2 and srf-3 mutants (Politz S. M., M. T. Philipp, M. Estevez, P.J. OBrien, and K. J. Chin. 1990. Proc. Natl. Acad. Sci. USA. 87:2901-2905), the antigen is not detected on the surface of any stage. Conversely, in srf-(yj43) and other similar mutants, the antigen is expressed on the surface of the first through the fourth (L4) larval stages. To understand the molecular basis of these alterations, the antigen was characterized in gel immunoblotting experiments. After SDS-PAGE separation and transfer to nitrocellulose, M38 detected a protein antigen in extracts of wild-type L1 populations. The antigen was sensitive to digestion by Pronase and O-glycanase ...
Defining a behavior that requires the function of specific neurons in the free-living nematode Caenorhabditis elegans can allow one to screen for mutations that disrupt the specification or function of those neurons. We identified serotonin-immunoreactive neurons required for tail curling or turnin …
The vaccinia-related kinases (VRKs) are highly conserved throughout the animal kingdom and phosphorylate several chromatin proteins and transcription factors. In early Caenorhabditis elegans embryos, VRK-1 is required for proper nuclear envelope formation. In this work, we present the first investigation of the developmental role of VRKs by means of a novel C. elegans vrk-1 mutant allele. We found that VRK-1 is essential in hermaphrodites for formation of the vulva, uterus, and utse and for development and maintenance of the somatic gonad and thus the germ line. VRK-1 regulates anchor cell polarity and the timing of anchor cell invasion through the basement membranes separating vulval and somatic gonadal cells during the L3 larval stage. VRK-1 is also required for proper specification and proliferation of uterine cells and sex myoblasts. Expression of the fibroblast growth factor-like protein EGL-17 and its receptor EGL-15 is reduced in vrk-1 mutants, suggesting that VRK-1 might act at least ...
The role of lipids in the process of embryonic development of Caenorhabditis elegans is still poorly understood. Cytochrome P450s, a class of lipid-modifying enzymes, are good candidates to be involved in the production or degradation of lipids essential for development. We investigated two highly similar cytochrome P450s in C. elegans, cyp-31A2 and cyp-31A3, that are homologs of the gene responsible for Bietti crystalline corneoretinal dystrophy in humans. Depletion of both cytochromes either by RNAi or using a double deletion mutant, led to the failure of establishing the correct polarity of the embryo and to complete the extrusion of the polar bodies during meiosis. In addition, the egg became osmotic sensitive and permeable to dyes. The phenotype of cyp-31A2 or cyp-31A3 is very similar to a class of mutants that have polarization and osmotic defects (POD), thus the genes were renamed to pod-7 and pod-8, respectively. Electron microscopic analysis demonstrated that the activity of pod-7/pod-8 ...
The C. elegans hermaphrodite vulva develops during postembryonic (larval) development from ventral epidermal precursors, and connects the developing uterus to the external environment. In the adult, the vulva is necessary for egg-laying (see Egg-laying) and for copulation with males (see Male mating behavior). Vulval development has attracted general interest for three main reasons. First, it serves as a paradigm for organogenesis. In particular, vulva development represents a well-understood case in which invariant development arises from multiple cell-cell interactions. It is also a striking example of tissue remodeling: the formation of a hole at a precise location in an organism. Second, it has been important for the genetic analyses of signaling and signal transduction by epidermal growth factor (EGF)-receptor LET-23 and RAS LET-60; (see RTKRas/MAP kinase signaling), LIN-12 (see LIN-12/Notch signaling in C. elegans), and WNT (see Wnt signaling), as well as the functions of the SynMuv and ...
The C. elegans hermaphrodite vulva develops during postembryonic (larval) development from ventral epidermal precursors, and connects the developing uterus to the external environment. In the adult, the vulva is necessary for egg-laying (see Egg-laying) and for copulation with males (see Male mating behavior). Vulval development has attracted general interest for three main reasons. First, it serves as a paradigm for organogenesis. In particular, vulva development represents a well-understood case in which invariant development arises from multiple cell-cell interactions. It is also a striking example of tissue remodeling: the formation of a hole at a precise location in an organism. Second, it has been important for the genetic analyses of signaling and signal transduction by epidermal growth factor (EGF)-receptor LET-23 and RAS LET-60; (see RTKRas/MAP kinase signaling), LIN-12 (see LIN-12/Notch signaling in C. elegans), and WNT (see Wnt signaling), as well as the functions of the SynMuv and ...
A specific behavioural response of Caenorhabditis elegans, the rapid increase of locomotion in response to anoxia/reoxygenation called the O2-ON response, has been used to model key aspects of ischaemia/reperfusion injury. A genetic suppressor screen demonstrated a direct causal role of CYP (cytochrome P450)-13A12 in this response and suggested that CYP-eicosanoids, which in mammals influence the contractility of cardiomyocytes and vascular smooth muscle cells, might function in C. elegans as specific regulators of the body muscle cell activity. In the present study we show that co-expression of CYP-13A12 with the NADPH-CYP-reductase EMB-8 in insect cells resulted in the reconstitution of an active microsomal mono-oxygenase system that metabolized EPA (eicosapentaenoic acid) and also AA (arachidonic acid) to specific sets of regioisomeric epoxy and hydroxy derivatives. The main products included 17,18-EEQ (17,18-epoxyeicosatetraenoic acid) from EPA and 14,15-EET (14,15-epoxyeicosatrienoic acid) ...
RNA interference (RNAi) is a widespread and widely exploited phenomenon which has potential as a strategy for both the treatment of disease and pest control. RNAi results in down‐regulation of a specific gene in response to the production of small interfering RNAs (siRNAs). RNAi is one of a family of processes mediated by small non‐coding RNAs [1], [2]. In Caenorhabditis elegans, and in a number of other organisms, RNAi is systemic so that the introduction of dsRNA into one tissue triggers gene silencing in other tissues [3], [4], [5], [6], [7]. Furthermore, systemic RNAi enables C. elegans and other organisms to exhibit environmental RNAi [5]. For example, feeding C. elegans on bacteria expressing dsRNA initiates a widespread RNAi response [8], [9]. Studies in C. elegans and other organisms have provided mechanistic insights into RNAi [4], [10], [11], [12], [13], although the role of exogenous RNAi in the normal life of C. elegans and other animals remains unclear [14].. Whilst C. elegans ...
Caenorhabditis elegans MIG-13 protein: required for positioning of Q neuroblasts and their descendents along the anteroposterior axis; isolated from Caenorhabditis elegans; amino acid sequence in first source; GenBAnk AF150958
Many crucial events in metazoan development and physiology are governed by diffusible signals that trigger specific responses in highly restricted subsets of cells. This exquisite specificity of intercellular signaling requires precisely controlled expression of receptors and downstream signaling components that effect appropriate responses. The nematode Caenorhabditis elegans has proven a valuable model for the study of signaling specificity, notably for mechanisms of signaling through the Epidermal growth factor (EGF) receptor (for a review, see Moghal and Sternberg, 2003). The sole EGF-like ligand and EGF receptor in the C. elegans genome are encoded by the genes lin-3 and let-23, respectively (Hill and Sternberg, 1992; Aroian et al., 1990) (Wormbase WS210). Recently we described a role for LET-23 in the regulation of C. elegans behavior (Van Buskirk and Sternberg, 2007). Caenorhabditis elegans develops through four larval stages before adulthood, and each larval molt is preceded by ...
A search of the C. elegans genome for potential homologues of the yeast MEN/SIN genes revealed several candidate genes, although for some of these genes the sequence similarities were only limited and for TEM1, CDC15, and BFA1 no putative homologues could be identified (Table I). All candidate genes were tested in C. elegans for a possible function in a hypothetical MEN/SIN-like regulatory network, using RNAi to deplete the corresponding products. For depletion of putative MEN/SIN gene products, both RNAi feeding and injection methods (Montgomery and Fire, 1998; Timmons et al., 2001) were tried to maximize the probability of functional inactivation. The results of these experiments are summarized in Table I. A priori, we had expected that depletion of a gene product required for the regulation of mitotic exit or the onset of cytokinesis should result in embryonic lethality. However, of all components tested, only the depletion of the C. elegans homologue of the budding yeast Cdc14p phosphatase ...
Abstract. Studies of the molecular mechanisms that are involved in stress responses (environmental or physiological) have long been used to make links to disease states in humans. The nematode model organism, Caenorhabditis elegans, undergoes a state of hypometabolism called the dauer stage. This period of developmental arrest is characterized by a significant reduction in metabolic rate, triggered by ambient temperature increase and restricted oxygen/ nutrients. C. elegans employs a number of signal transduction cascades in order to adapt to these unfavourable conditions and survive for long times with severely reduced energy production. The suppression of cellular metabolism, providing energetic homeostasis, is critical to the survival of nematodes through the dauer period. This transition displays molecular mechanisms that are fundamental to control of hypometabolism across the animal kingdom. In general, mammalian systems are highly inelastic to environmental stresses (such as extreme ...
Pun, P.B.L., Gruber, J., Tang, S.Y., Ng, L.F., Cheah, I., Halliwell, B., Ong, R.L.S., Fong, S. (2010). Ageing in nematodes: Do antioxidants extend lifespan in Caenorhabditis elegans?. Biogerontology 11 (1) : 17-30. [email protected] Repository. https://doi.org/10.1007/s10522-009-9223- ...
gi,17559712,ref,NP_506256.1, CaDHerin family member (cdh-6) [Caenorhabditis elegans] gi,7499172,pir,,T20968 hypothetical protein F15B9.7 - Caenorhabditis elegans gi,3875964,emb,CAB01427.1, Hypothetical protein F15B9.7 [Caenorhabditis elegans] gi,3880568,emb,CAB01449.1, C. elegans CDH-6 protein (corresponding sequence F15B9.7) [Caenorhabditis elegans ...
RNA-mediated interference (RNAi) has emerged recently as one of the most powerful functional genomics tools. RNAi has been particularly effective in the nematode worm C. elegans where RNAi has been used to analyse the loss-of-function phenotypes of almost all predicted genes. In this review, we illustrate how RNAi has been used to analyse gene function in C. elegans as well as pointing to some future directions for using RNAi to examine genetic interactions in a systematic manner.. ...
For the first days, we will introduce students to the nematode C. elegans. Students will work with different experimental set-ups that will allow us to explore a variety of C. elegans behavior. We will analyze C. elegans behavior in response to thermal, mechanical and chemical stimuli. The transparency of the animal makes it feasible to use genetically encoded calcium sensors to monitor neural activity in response to sensory stimuli. Transgenic expression of light-activated ion channels, allows us to turn neurons on and off. These optogenetic experiments will be used to define neural requirements of sensory processing. Students will use these techniques to determine 1) how C. elegans responds and remembers the temperature at which was raised; 2) analyze the neural dynamics of a compound motor sequence that is evoked by touch; 3) determine the neural requirements of calcium channels chemosensation. These experiments are an ideal introduction to Calcium imaging optogenetics in a genetically ...
Eit vakse individ har kring 1 000 seller, og dette talet er konstant; vaksne individ veks berre ved at sellene vert større.[2][3] C. elegans har to kjønnskategoriar: tvikjønn og hankjønn. Tvikjønna makkar kan fræva seg sjølve, medan hannmakkar berre kan fræva tvikjønna makkar.[4] Meltesystemet til C. elegans har 20 epitelseller som liknar på dei ein finn hjå menneske. C. elegans har ikkje immunseller.[2] Det ytre laget av C. elegans vert laga og skilt ut av 12 seller med til saman 157 sellekjernar.[3] Langs sidene av vaksne C. elegans-individ går det òg to band kalla alae, skilte ut av samansmelta saumseller.[5] Nervesystemet til C. elegans er det mest komplekse vevet i organismen. Hjå tvikjønna makkar utgjer det kring 37% av alle kroppssellene. Tvikjønna makkar har 302 nerveseller fordelte på 118 ulike typar og 56 gliaseller. Hannar har 385 nerveseller og soleis fleire enn tvikjønna. Dei fleste ekstra nervesellene hjå hannane sit i halen. Hannane har åtferd knytt til ...
Mutations in clk-1 slow down development and extend lifespan by 30% [946]. Food restriction by eat-2 mutation does not further extend the long lifespan of clk-1 mutant [1820]. DR and clk-1 mutations may extend lifespan by a similar process. DR by intermittent fasting significantly extends lifespan of clk-1 mutants, but to a lesser extent than that of wild-type [2566]. clk-1 mutants do not respond to solid DR-induced lifespan extension [2568]. clk-1 mutants have a decreased pharyngeal pumping that may provoke voluntary DR [1820]. ...
The nematode Caenorhabditis elegans may hold the key to brain-like computational architectures: Si elegans will provide the scientific community with a reconfigurable, scalable and modular neuromimetic open-access computational platform to explore neural principles that give rise to complex behaviour and to derive a neuro-inspired technological blueprint for a new era of brain-like computational architectures.The Si elegans project started on April 1st 2013. ...
Much of the material taken into cells by endocytosis is rapidly returned to the plasma membrane by the endocytic recycling pathway. Although recycling is vital for the correct localization of cell membrane receptors and lipids, the molecular mechanisms that regulate recycling are only partially understood. Here we show that in C. elegans, endocytic recycling is inhibited by NUM-1A, the nematode Numb homologue. NUM-1A::GFP fusion protein is localized to the baso-lateral surfaces of many polarized epithelial cells including the hypodermis and the intestine. We show that increased NUM-1A levels cause morphological defects in these cells similar to those caused by loss-of-function mutations in rme-1, a positive regulator of recycling both in C. elegans and mammals. We describe the isolation of worms lacking num-1A activity and show that, consistent with a model in which NUM-1A negatively regulates recycling in the intestine, loss of num-1A function bypasses the requirement for RME-1. Genetic ...
C elegans Unc-7 protein: Innexin, required for coordinated locomotion in Caenorhabditis elegans; amino acid sequence given in first source; GenBank Z19122
The C. elegans grinder is an intricately designed, macromolecular structure located in the terminal bulb of the pharynx. It acts as the teeth of C. elegans, crushing bacteria before they are passed to the intestine. The ...
A mutation in the let-653 gene of Caenorhabditis elegansresults in larval death. The lethal arrest is concurrent with the appearance of a vacuole anterior to the lower pharyngeal bulb. The position...
unc-51(e369) mutation reduces mean but extends maximum lifespan. unc-51(e369) mutation reduces lifespan of eat-2 mutants to that of wild-type [2387]. ...
Automated behavioural fingerprinting of C. elegans mutants: Rapid advances in genetics, genomics, and imaging have given insight into the molecular and cellular
The let-7 miRNA was originally discovered in the nematode Caenorhabditis elegans, where it regulates cell proliferation and differentiation, but subsequent work has shown that both its sequence and its function are highly conserved in mammals ...
The main focus of our research is the study of neuronal function and dysfunction, using the nematode Caenorhabditis elegans as a model organism. Among...
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
Next-day shipping cDNA ORF clones derived from nck-1 NCK (Non-Catalytic region of tyrosine Kinase) adaptor protein family available at GenScript, starting from $99.00.
Please note: Your browser does not support the features used on Addgenes website. You may not be able to create an account or request plasmids through this website until you upgrade your browser. Learn more ...
JoVE publishes peer-reviewed scientific video protocols to accelerate biological, medical, chemical and physical research. Watch our scientific video articles.
We have developed a Petri net model of C. elegans vulval development process. The model is available in the following formats: ...
Nematocida parisii ATCC ® PRA-289™ Designation: ERTm1 Isolation: Wild-caught Caenorhabditis elegans isolated from a compost pit, Franconville, France ref
Vol 4: A method to identify and validate mitochondrial modulators using mammalian cells and the worm C. elegans.. This article is from Scientific Reports, volume 4.AbstractMitochondria are semi-autonomous organelles regulated by a com. Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
Ninety-five mutants of the nematode Caenorhabditis elegans altered in the cell lineages of the vulva have been isolated on the basis of their displaying one of two phenotypes, Vulvaless or Multivulva. In Vulvaless mutants, which define 12 genes, no vulva is present. In Multivulva mutants, which define ten genes, one or more supernumerary vulva-like protrusions are located along the ventral side of the animal. A single recessive mutation is responsible for the phenotypes of most, but not all, of these strains. Fifteen of these 22 genes are represented by multiple alleles. We have shown by a variety of genetic criteria that mutations that result in a Vulvaless or Multivulva phenotype in six of the 22 genes most likely eliminate gene function. In addition, Vulvaless or Multivulva mutations in seven of the other genes most likely result in a partial reduction of gene function; the absence of the activity of any of these genes probably results in lethality or sterility. Our results suggest that we ...
Brenner, S. (1974). The genetics of Caenorhabditis elegans. Genetics 77, 71-94.. Chitwood, B. G., and Chitwood, M. B. (1974). Introduction to Nematology. University Park Press, Baltimore.. Hodgkin, J. A. (1974). Genetic and Anatomical Aspects of the Caenorhabditis elegans Male, Ph.D. thesis. University of Cambridge, Cambridge, England.. Hodgkin, J. A., and Brenner, S. (1977). Mutations causing transformation of sexual phenotype in the nematode Caenorhabditis elegans. Genetics 86, 275-287.. Kimble, J., and Hirsh, D. (1979). The Postembryonic cell lineages of the hermaphrodite and male gonads in Caenorhabditis elegans. Develop. Biol. 70, 396-417.. Klass, M., Wolf, N., and Hirsh, D. (1976). Development of the male reproductive system and sexual transformation in the nematode Caenorhabditis elegans. Develop. Biol. 52, 1-18.. Seligman, I. M., Filshie, B. K., Doy, F. A., and Crossley, A. C. (1975). Hormonal control of mor-phogenetic cell death of the wing hypodermis in Lucilia cuprina. Tissue Cell ...
During the course of normal embryonic and post-embryonic development, 131 cells in a Caenorhabditis elegans hermaphrodite undergo programmed cell death. Loss of function mutations in either of the genes ced-3 or ced-4 abolish cell deaths, enabling these undead cells to survive and be incorporated into the adult with no obvious deleterious consequences. Ultrastructural reconstructions have shown that undead cells exhibit many differentiated characteristics. Most of the reconstructed cells appeared to be neurons with all the characteristic features associated with such cells, such as processes, synaptic vesicles and presynaptic specializations. However, clear morphological differences were seen among the undead neurons, suggesting a diversity of cell type. One of the reconstructed cells was a rectal epithelial cell, which had displaced its lineal sister that normally functions in this role. Removal of the ability to undergo programmed cell death by mutation therefore reveals a diversity of ...
When cultures of C. elegans become crowded and exhaust their food supply, dauer formation results (Cassada and Russell, 1975). Wild-type larvae typically do not enter dauer at temperatures at or below 25 °C when there is any food on the plate, even a small amount, unless high concentrations of pheromone are added by one of the methods discussed in Section 3.2 and Section 3.3. Immediately after exhausting the food supply, most of the larvae will enter L1 arrest/L1 diapause (Johnson et al., 1984). Some will remain arrested and others will continue on to the dauer stage. Thus, the first dauer larvae do not appear until at least a few days after exhaustion of the food supply. By contrast, very old plates contain relatively fewer dauer larvae. Dauer larva survival decreases with time, whereas the propensity to recover from dauer increases (Klass and Hirsh, 1976; Golden and Riddle, 1984b). In wild-type cultures, there is always a mix of stages observed on the plates. The percentage of dauer larvae ...
Early Caenorhabditis elegans embryos provide an excellent model for the study of developmental processes. Development can be studied by direct observation under the light microscope and can be perturbed using laser manipulations, drug inhibitor treatments, and genetic mutants. The first division of the C. elegans embryo is asymmetric, generating two daughter cells unequal in size and developmental fate. These distinct fates are generated by the partitioning of cytoplasmic determinants during the first mitotic cell cycle. Partitioning of these determinants is thought to be driven by cytoplasmic flow. Recent studies in C. elegans in the past year have identified a number of components necessary for this flow, giving us a clearer picture of the molecular mechanisms underlying developmental asymmetry.
A genetic screen for Caenorhabditis elegans mutants with enhanced susceptibility to killing by Pseudomonas aeruginosaled to the identification of two genes required for pathogen resistance: sek-1, which encodes a mitogen-activated protein (MAP) kinase kinase, and nsy-1, which encodes a MAP kinase kinase kinase. RNA interference assays and biochemical analysis established that a p38 ortholog, pmk-1, functions as the downstream MAP kinase required for pathogen defense. These data suggest that this MAP kinase signaling cassette represents an ancient feature of innate immune responses in evolutionarily diverse species. ...