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Trends Genet,
2002]
Studies in Caenorhabditis elegans demonstrate that disruption of the
daf-2 signaling pathways extends lifespan. Similarities among the
daf-2 pathway, insulin-like signaling in flies and yeast, and the mammalian insulin-like growth factor 1 (IGF-1) signaling cascade raise the possibility that modifications to IGF-1 signaling could also extend lifespan in mammals. In fact, growth hormone (GH)/IGF-1-deficient dwarf mice do live significantly longer than their wild-type counterparts. However, multiple endocrine deficiencies and developmental anomalies inherent in these models confound this interpretation. Here, we critique the current mammalian models of GH/IGF-1 deficiency and discuss the actions of GH/IGF-1 on biological aging and lifespan.
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Curr Top Dev Biol,
2000]
The main advantage of C. elegans as an experimental model lies in its simplicity. The full-grown adult is about 1 mm in length and composed of fewer than 1000 somatic nuclei. It has a short reproductive cycle of approximately 3 days and simple nutritional requirements, feeding primarily on bacteria....
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Methods Mol Biol,
2006]
High-pressure freezing (HPF) is capable of converting liquid water, to a depth of approx 0.6 mm, into amorphous ice nearly instantaneously. At midbody, an adult Caenorhabditis elegans hermaphrodite approaches its widest girth of approx 0.1 mm. In theory, an entire living adult animal can be physically immobilized instantly in amorphous ice by HPF, thus, providing a unique opportunity to examine cellular architecture with exquisite spatial preservation. The following chapter will discuss, in detail, procedures for freezing C. elegans under high pressure, for embedding frozen samples in resin after a freeze-substitution step, and for the postembedding immunogold labeling of proteins contained within thin sections of embedded animals. These protocols enable high-resolution analysis of both morphological features and molecular domains within most tissues of C. elegans.
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2017]
Caenorhabditis elegans is a 1-mm-long free-living nematode that feeds on bacteria. The feeding organ of C. elegans is a pharynx, a neuromuscular tube responsible for sucking bacteria into the worm from outside, concentrating them, and grinding them up (Doncaster 1962, Seymour et al. 1983). The basic mechanics and the neurons and muscles used to execute feeding motion are important for understanding several feeding behaviors and are therefore briefly described. More details regarding cellular and nuclear composition, the structure, electrophysiology, and the molecular components can be found in Avery and You (2012).
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Annu Rev Neurosci,
1993]
Behavior arises through the interplay of innate properties of the nervous system, environmental stimuli, and experience. An opportunity to integrate neuronal and genetic approaches to study behavior is provided by the soil nematode Caenorhabditis elegans. C. elegans is attractive for study because of the simplicity and accessibility of its nervous system. The adult hermaphrodite is 1 mm long, and its nervous system is composed of only 302 neurons. The nucleus of each neuron can be identified in live animals by differential interference microscopy, and the cell lineage that gives rise to each of these neurons has been described in its entirety. C. elegans develops to adulthood in about three days at 25C, which facilitates observation of its
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[
2017]
Since their discovery in late 1970, transient receptor potential (TRP) channels have been implicated in a variety of cellular and physiological functions (Minke, 2010). The superfamily of TRP channels consists of nearly 30 members that are organized into seven major subgroups based on their specific function and sequence similarities (Owsianik et al., 2006; Ramsey et al., 2006). With the exception of TRPN channels that are only found in invertebrates and fish, mammalian genomes contain representatives of all six subfamilies: (1) TRPV (vanilloid); (2) TRPC (canonical); (3) TRPM (melastatin); (4) TRPA (ankyrin); (5) TRPML (mucolipin); and (6) TRPP (polycystin). TRP channels play crucial regulatory roles in many physiological processes, including those associated with reproductive tissues. As calcium-permeable cation channels that respond to a variety of signals (Clapham et al., 2003; Wu et al., 2010), TRP channels exert their role as sensory detectors in both male and female gametes, and play regulatory functions in germ cell development and maturation. Recent evidence obtained from Caenorhabditis elegans studies point to the importance of these proteins during fertilization where certain sperm TRP channels could migrate from a spermatozoon into an egg to ensure successful fertilization and embryo development. In this chapter we discuss how TRP channels can regulate both female and male fertility in different species and their specific roles.
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J Fungi (Basel),
2018]
<i>C. elegans</i> has several advantages as an experimental host for the study of infectious diseases. Worms are easily maintained and propagated on bacterial lawns. The worms can be frozen for long term storage and still maintain viability years later. Their short generation time and large brood size of thousands of worms grown on a single petri dish, makes it relatively easy to maintain at a low cost. The typical wild type adult worm grows to approximately 1.5 mm in length and are transparent, allowing for the identification of several internal organs using an affordable dissecting microscope. A large collection of loss of function mutant strains are readily available from the <i>C. elegans</i> genetic stock center, making targeted genetic studies in the nematode possible. Here we describe ways in which this facile model host has been used to study <i>Candida albicans</i>, an opportunistic fungal pathogen that poses a serious public health threat.
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Angew Chem Int Ed Engl,
2011]
This Review discusses the potential usefulness of the worm Caenorhabditis elegans as a model organism for chemists interested in studying living systems. C. elegans, a 1 mm long roundworm, is a popular model organism in almost all areas of modern biology. The worm has several features that make it attractive for biology: it is small (<1000 cells), transparent, and genetically tractable. Despite its simplicity, the worm exhibits complex phenotypes associated with multicellularity: the worm has differentiated cells and organs, it ages and has a well-defined lifespan, and it is capable of learning and remembering. This Review argues that the balance between simplicity and complexity in the worm will make it a useful tool in determining the relationship between molecular-scale phenomena and organism-level phenomena, such as aging, behavior, cognition, and disease. Following an introduction to worm biology, the Review provides examples of current research with C. elegans that is chemically relevant. It also describes tools-biological, chemical, and physical-that are available to researchers studying the worm.
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Ing Rech Biomed,
2008]
Because the entire genome of Caenorhabditis elegans (C. elegans) is available for exploration since 1998, several information have been retrieved about the global interest of this organism when it became apparent that the similarity of genes in this 1 mm length nematode and those in humans is remarkable, with approximately 67% of genes that are associated with human disease having homologues in the worm genome. C. elegans worms can be easily maintained on various food-sources and culture media allowing testing for molecules or treatments in combination with different genetic mutants backgrounds as well as RNA interference (RNAi). Because of regulatory pathways conservation between humans and worms, several interesting strategies can be developed to facilitate drugs screenings on specific targets as well as to decipher complex physiological programmed traits with potential identification of new therapeutic targets interesting for human health. By using specific examples, we propose to introduce how to use the already available C. elegans data-cross that can be used as a basis for developing new therapeutic targets identification strategies.
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Int J Mol Sci,
2016]
Caenorhabditis elegans, a 1 mm long free-living nematode, is a popular model animal that has been widely utilized for genetic investigations of various biological processes. Characteristic features that make C. elegans a powerful model of choice for eukaryotic genetic studies include its rapid life cycle (development from egg to adult in 3.5 days at 20 C), well-annotated genome, simple morphology (comprising only 959 somatic cells in the hermaphrodite), and transparency (which facilitates non-invasive fluorescence observations). However, early approaches to introducing mutations in the C. elegans genome, such as chemical mutagenesis and imprecise excision of transposons, have required large-scale mutagenesis screens. To avoid this laborious and time-consuming procedure, genome editing technologies have been increasingly used in nematodes including C. briggsae and Pristionchus pacificus, thereby facilitating their genetic analyses. Here, I review the recent progress in genome editing technologies using zinc-finger nucleases (ZFNs), transcriptional activator-like nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 in nematodes and offer perspectives on their use in the future.