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[
WormBook,
2005]
Alternative splicing is a common mechanism for the generation of multiple isoforms of proteins. It can function to expand the proteome of an organism and can serve as a way to turn off gene expression post-transcriptionally. This review focuses on splicing and its regulation in C. elegans. The fully-sequenced C. elegans genome combined with its elegant genetics offers unique advantages for exploring alternative splicing regulation in metazoans. The topics covered in this review include constitutive splicing factors, identification of alternatively spliced genes, examples of alternative splicing in C. elegans, and alternative splicing regulation. Key genes whose regulated alternative splicing are reviewed include
let-2 ,
unc-32 ,
unc-52 ,
egl-15 and
xol-1 . Factors involved in alternative splicing that are discussed include
mec-8 ,
smu-1 ,
smu-2 ,
fox-1 ,
exc-7 and
unc-75 .
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[
Methods Cell Biol,
1995]
The nematode Caenorhabditis elegans is a small, rapidly growing organism that can easily be raised in the laboratory on the bacterium Escherichia coli. Because C. elegans is a self-fertilizing hermaphrodite, it is possible to readily grow large quantities of the organism in swirling liquid cultures and also possible to propagate severely incapacitated mutants. The rapidity of growth and the ability to self-fertilize necessitate special measures to establish a synchronous culture.
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[
Methods Cell Biol,
1995]
Behavioral plasticity is the ability of organisms to modify their behavior over time, based on their experience, and is thus critical to the survival of any organism in a changing environment. It allows organisms to adapt to new surroundings and to take better advantage of novel situational variables they may encounter. It is therefore an extremely important ability, and it has attracted much research attention in innumberable organisms and across several disciplines. Much of the research on plasticity has been characterized by an attempt to integrate information and expertise from a number of these different disciplines within selected invertebrate organisms. Researchers from a variety of fields, including psychology, physiology, biochemistry, genetics, neurobiology, and molecular biology, have been uniting in an effort to investigate "simple system" in which these approaches are being combined and focused on the general goal of elucidating the cellular, molecular, and genetic basis of behavioral plasticity. These simple system approaches have led to considerable progress in our understanding of the mechanisms underlying adaptive behaviors. The general strategy of such approaches is to try to identify the genes, molecules, channels, ion currents, cells, and neural circuits underlying some form of plasticity and then determine the precise nature of their respective roles in producing behavior...
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[
1974]
The free-living nematode, Caenorhaditis briggsae, is being used in our laboratory to study the complex events associated with biological aging. Our approach to this problem involved first the defining of parameters characterizing senescence in this animal, and then evaluating the effects on these aging signs of a drug reported to have a modifying effect on some aspects of the aging processes. Reference in this report to this preparation, Gerovital H3 (2% procaine hydrochloride, 0.16% benzoic acid, 0.14% potassium metabisulfite, buffered to pH 3.3 from Rom-Amer Pharmaceuticals, Ltd., Beverly Hills, California) is by its active ingredient, "Procaine".
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[
1969]
In order to study properly the nutrition and culture of nematodes, it is desirable to establish the organisms in axenic culture. Only in this way can the metabolic abilities of the nematodes be separated from those of coexisting and interacting organisms. One may settle for a mono-axenic culture, but the best way to attain this is to obtain axenic nematodes and then add the second organism or tissue, for example, alfalfa callus tissue for plant parasitic nematodes (Krusberg, 1961). This chapter will devote itself, in the main, to recent work on the culture and nutrition of nematodes, free-living and parasitic, and will refer only in passing to work already thoroughly reviewed (Dougherty et al., 1959; Nicholas, et al., 1959; Dougherty, 1960).
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[
1994]
In order to contribute to the understanding of the organization and function of genes in the genome of Caenorhabditis elegans, we have undertaken a genetic approach. This type of approach relies upon the availability of mutant strains. Although there are many specific applications, in general genetic deduction depends upon the removal of a single component, and subsequent inference from phenotypic alterations as to the function of that component. The biology of C. elegans makes it very amenable to genetic manipulation...
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[
2003]
During development and homeostasis, individual cells must divide, differentiate, migrate, adapt to the environment, or die at the appropriate times and places. A key to deciphering the molecular mechanisms by which cells make these decisions is to characterize the regulation and function of the proteins that regulate important changes in gene expression. The family of transcription factors that contain basic-helix-loop-helix and PAS motifs has been shown to control many critical developmental events and to mediate responses to certain environmental stimuli. For example, bHLH-PAS proteins play central roles in the development of specific neural tissues and vasculature, and they are core components of the molecular clock that govern circadian rhythms. bHLH-PAS proteins are also integral to the pathways that sense and respond to hypoxia (low oxygen) and certain xenobiotics (1). Phylogenetic analyses suggest that bHLH-PAS genes arose early in animal development, and in some cases, the functions of individual genes are largely conserved across phyla. This review describes the bHLH-PAS gene family in a genetic model organism, the nematode Caenorhabditis elegans.
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[
2010]
Over 30 years ago, Nobel laureate Sydney Brenner recognized that an intellectually straightforward strategy to delineate the basic principles in neurobiology is to utilize a model organism with a nervous system that is simple enough to lend itself to anatomical, cellular, genetic, and molecular analysis, yet be complex enough that lessons learned in that organism would give us insight into general principles of neural function. The humble organism he chose, the nematode Caenorhabditis elegans, is now one of the most thoroughly characterized metazoans, particularly in terms of its nervous system. One of Brenner's motivations in adapting C. elegans as a model organism was to understand the totality of the molecular and cellular basis for the control of animal behavior (Brener 1988). In this chapter, we review what is arguably the best-studied aspect of C. elegans behavior: response to chemical stimuli. The C. elegans neurobiology literature can be intimidating for the uninitiated; we attempt to limit the use of "worm jargon" in this review. For a more C. elegans-centric review, we refer you to other excellent sources (Bargmann 2006).
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[
WormBook,
2007]
Four biogenic amines: octopamine, tyramine, dopamine and serotonin act in C. elegans to modulate behavior in response to changing environmental cues. These neurotransmitters act at both neurons and muscles to affect egg laying, pharyngeal pumping, locomotion and learning. A variety of experimental approaches including genetic, imaging, biochemical and pharmacological analyses have been used to identify the enzymes and cells that make and release the amines and the cells and receptors that bind them. Dopamine and serotonin act through receptors and downstream signaling mechanisms similar to those that operate in the mammalian brain suggesting that C. elegans will provide a valuable model for understanding biogenic amine signaling in the brain.
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[
2006]
In the development and use of animal models of cognitive dysfunction, it is important to develop complementary models to exploit the unique advantages of the different species. Nonmammalian vertebrates such as fish provide the opportunity to directly observe neurodevelopmental processes and determine the impact of developmental permutations on learning and memory. Zebrafish in particular are valuable because of the availability of morpholine techniques to transiently suppress specific parts of genomic expression. Invertebrate models such as C. elegans and drosophila provide other advantages, particularly the elegant genetic manipulations available. The simple nervous systems in these models are useful in determining mechanisms of cognitive function. The development of new methods for high-throughput tests of cognitive function for fish can provide a means for rapid screening of potential toxic agents as well as promising therapeutic agents. It is equally important to develop specific tests of various aspects of cognitive function, including habituation, associative learning, memory, and attention as well as to be able to differentiate changes in sensorimotor function from cognition. Key in the use of nonmammalian models is the determination of which mechanisms of cognitive function are similar to mammals and which are different. Nonmammalian models can be used in concert with classic mammalian models to determine the neural bases of cognitive function and to aid in the discovery of toxicants and potential therapeutic agents.