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Naturally occurring or programmed cell deaths, which play important roles in animal development and homeostasis, are observed in a wide variety of tissues in both vertebrates and invertebrates. Such deaths remove cells that might be harmful, are not needed, or have served their purpose. In many tissues, cell death and cell proliferation are precisely balanced, to maintain the proper number of types of cells. Disruption of this balance can result in disease. Both cell death and aging appear to be under genetic control. Identification of the genes involved in these processes promises to greatly enhance our understanding of these phenomena.
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[
Methods Mol Biol,
2012]
Cellular effects of primary mitochondrial dysfunction, as well as potential mitochondrial disease therapies, can be modeled in living animals such as the microscopic nematode, Caenorhabditis elegans. In particular, molecular analyses can provide substantial insight into the mechanism by which genetic and/or pharmacologic manipulations alter mitochondrial function. The relative expression of individual genes across both nuclear and mitochondrial genomes, as well as relative quantitation of mitochondrial DNA content, can be readily performed by quantitative real-time PCR (qRT-PCR) analysis of C. elegans. Additionally, microarray expression profiling offers a powerful tool by which to survey the global genetic consequences of various causes of primary mitochondrial dysfunction and potential therapeutic interventions at both the single gene and integrated pathway level. Here, we describe detailed protocols for RNA and DNA isolation from whole animal populations in C. elegans, qRT-PCR analysis of both nuclear and mitochondrial genes, and global nuclear genome expression profiling using the Affymetrix GeneChip C. elegans Genome Array.
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[
1987]
Current knowledge of sterol biochemistry and physiology in nematodes is reviewed. Nematodes possess a nutritional requirement for sterol because they lack the capacity for de novo sterol biosynthesis. The free-living nematode Caenorhabditis elegans has recently been used as a model organism for investigation of nematode sterol metabolism. C. elegans is capable of removal of the C-24 alkyl substituent of plant sterols such as sitosterol and also possesses the remarkable ability to attach a methyl group at C-4 on the sterol nucleus. An azasteroid and several long-chain alkyl amines disrupt the phytosterol dealkylation pathway in C. elegans by inhibiting its *24-sterol reductase. These compounds inhibit growth and reproduction in certain parasitic nematodes and provide model compounds for development of novel nematode control
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[
WormBook,
2006]
Many pathogens that can infect C. elegans have been described, including some that co-exist with the nematode in its natural environment. This chapter describes our current understanding of the different innate immune responses of C. elegans that follow infection. It focuses on the main signalling pathways that have been identified and highlights the inclusion of certain molecular cassettes in both immune and developmental functions.
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[
1984]
The switching on or off of specific genes is a fundamental aspect of cellular differentiation during metazoan development. The molecular events involved in this switching are not yet understood, but they are now subject to analysis with the current technology available in molecular biology. Much of the work directed toward the understanding of developmental gene regulation has focused on the genes encoding the protein actin. Actin is the major thin-filament protein in both muscle and nonmuscle cells. The protein sequences of actins from a variety of tissues in several organisms have been determined, and the actin genes from a number of organisms have been isolated and are currently being studied. This work has revealed that actins are evolutionarily conserved, are encoded in most species by multigene families, and are differentially regulated, both spatially and temporally, during
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[
2011]
Transient receptor potential (TRP) family channels are conserved from Caenorhabditis elegans to humans. About 28 TRP members have been identified in mammals. On the basis of their sequence homology and functional similarity, these channels are further divided into seven subfamilies. Accumulating evidence shows that mammalian TRP channels are broadly involved in regulating sensory physiology, as they are important for sensing a wide variety of physical and chemical cues from both intracellular and extracellular sides.1
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[
WormBook,
2005]
Evolutionary innovation requires genetic raw materials upon which selection can act. The duplication of genes is of fundamental importance in providing such raw materials. Gene duplications are very widespread in C. elegans and appear to arise more frequently than in either Drosophila or yeast. It has been proposed that the rate of duplication of a gene is of the same order of magnitude as the rate of mutation per nucleotide site, emphasising the enormous potential that gene duplication has for generating substrates for evolutionary change. The fate of duplicated genes is discussed. Complete functional redundancy seems unstable in the long term. Most models require that equality amongst duplicated genes must be disrupted if they are to be preserved. There are various ways of achieving inequality, involving either the nonfunctionalization of one copy, or one copy acquiring some novel, beneficial function, or both copies becoming partially compromised so that both copies are required to provide the overall function that was previously provided by the single ancestral gene. Examples of C. elegans gene duplications that appear to have followed each of these pathways are considered.
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[
1981]
A neuron can be characterized by its morphology, transmitter (s?), receptor(s) and the nature of its synaptic contacts (chemical or electrical; excitatory or inhibitory; number and distribution of synapses; identity of the cells to which it is presynaptic or postsynaptic). It is clear that according to such criteria nervous sytems consist of neurons of many distinct types. The origin of neuronal diversity is unknown. Both how such diversity is generated during development and how the relevant developmental programme is encoded in the genome remain to
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The nematode cuticle, like the endo- and exo-skeletons of other animals, is much more than just an inert structure against which muscles can act during locomotion. The cuticle performs complex roles in organismal physiology, protection from the environment, nutrition and excretion. Cuticle composition and structure reflects this complexity. In this chapter we review briefly the ultrastructure of the cuticle and examine the biochemistry and genetics of the components of nematode cuticles. We also discuss the cuticle as a dynamic structure, both over the lifetime of the nematode (through the moults) and on shorter timescales.
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[
Methods Cell Biol,
1995]
The ultimate goal of subcellular fractionation and biochemical purification is to better understand the relationships between structure and function of proteins and protein assemblies. Examples of such relationships with respect to specific gene products include the formation of stable complexes, elucidation of catalytic activities, and subcellular localization of the organellar and supramolecular levels. The detailed aspects of such relationships are not always readily predictable from genetic or molecular studies of the gene products or from their cellular localization by immunological methods. Subcellular fractionation and biochemical purification are generally prerequisites to experimental analysis of biochemical mechanisms underlying a biological phenomenon. These approaches can mutually enhance and interact with parallel cellular, genetic, and molecular analyses. To achieve such goals, methods for isolating proteins and protein assemblies must preserve both structural integrity and biological activity. Ideally, both objectives should be met; practically, it may be critical to know which of these conditions is true. In general, specific protocols must be designed for the optimal isolation, purification, and characterization of each specific protein of interest. Additionally, one wishes to achieve as high a yield as possible; however, each step in protein purification generally produces some reduction in yield...