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Mol Reprod Dev,
1990]
Caenorhabditis elegans develops from the embryo, through four larval stages that are punctuated by molts, then to adulthood. There are two sexes: hermaphrodites and males. Hermaphrodites may reproduce by self-fertilization or they may mate with males to produce cross-progeny...
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Curr Opin Chem Biol,
2001]
Protein -interaction mapping approaches generate functional information for large numbers of genes that are predicted from complete genome sequences. This information, released as databases available on the Internet, is likely to transform the way biologists formulate and then address their questions of interest.
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Curr Biol,
2000]
Recent work on pattern formation in Caenorhabditis elegans has uncovered a new mechanism of asymmetric cell division: the cytoplasm is polarized by cortical proteins, and this polarization then influences the stability of other maternally expressed proteins that in turn determine early embryonic cell fates.
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Methods Mol Biol,
2006]
The methods used by the Caenorhabditis elegans Gene Knockout Consortium are conceptually simple. One does a chemical mutagenesis of wild-type C. elegans, and then screens the progeny of the mutagenized animals, in small mixed groups, using polymerase chain reaction (PCR) to identify populations with animals where a portion of DNA bounded by the PCR primers has been deleted. Animals from such populations are then selected and grown clonally to recover a pure genetic strain. We categorize the steps needed to do this as follows: (1) mutagenesis and DNA template preparation, (2) PCR detection of deletions, (3) sibling selection, and (4) deletion stabilization. These are discussed in detail in this chapter.
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BioEssays,
1997]
Axis specification is the first step in defining specific regions of the developing embryo. Embryos exploit asymmetries, either pre-existing in the egg or triggered by external cues, to establish embryonic axes. The axial information is then used to generate regional differences within the embryo. In this review, we discuss experiments in animals which address three questions: whether the unfertilized egg is constructed with pre-determined axes, what cues are used to specify the embryonic axes, and how these cues are interpreted to generate the initial regional differences within the embryo. Based on mapping the data onto an animal phylogeny, we then propose a scenario for how this primary developmental decision occurred in ancestral metazoans.
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Mol Reprod Dev,
2016]
Self-fertility has evolved many times in nematodes. This transition often produces an androdioecious species, with XX hermaphrodites and XO males. Although these hermaphrodites resemble females in most respects, early germ cells differentiate as sperm and late ones as oocytes. The sperm then receive an activation signal, populate the spermathecae, and are stored for later use in self-fertilization. These traits are controlled by complex modifications to the sex-determination and sperm activation pathways, which have arisen independently during the evolution of each hermaphroditic species. This transformation in reproductive strategy then promotes other major changes in the development, evolution and population structure of these animals. This article is protected by copyright. All rights reserved.
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J Cell Sci,
2003]
At the heart of synaptic transmission resides the synaptic vesicle cycle- a membrane trafficking pathway in which small membrane-bound vesicles mediate the release of neurotransmitter from presynaptic terminals. The cycle resembles general membrane trafficking and has three phases: vesicle filling, release and recycling. During filling, neurotransmitter is loaded into vesicles via vesicular neurotransmitter transporters. It is then released by exocytosis: vesicles dock with the plasma membrane and undergo a maturation step, termed priming; then, following influx of calcium through voltage-gated channels, a calcium sensor promotes fusion of the vesicle with the plasma membrane. Membrane fusion consumes vesicle membrane and vesicle proteins; thus, these components must be recycled to sustain neurotransmitter release.
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Interdiscip Top Gerontol,
2015]
This chapter will introduce a few additional network concepts, and then it will focus on the application of the material in the previous chapter to the study of systems biology of aging. In particular, we will examine how the material can be used to study aging networks in two sample species: Caenorhabditis elegans and Saccharomyces cerevisiae.
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Methods Cell Biol,
1995]
DNA transformation assays in a whole organism provide experimental links between molecular structure and phenotype. Experiments with transgenic Caenorhabditis elegans start in general with the injection of DNA into the adult gonad. Effects on phenotype or gene expression patterns can be analyzed either in F1 progeny derived from the injected animals or in derived transgenic lines. Microinjection of C. elegans was first carried out by Kimble et al. (1982). Stinchcomb et al. (1985) then showed that injected DNA could be maintained for several generations in transgenic lines. The first selective methods for producing and maintaining transgenic lines were reported in 1986 (Fire, 1986). These methods have been considerably improved since then (Mello et al., 1991) , so that assays involving DNA transformation are now a standard part of the experimental repertoire for C. elegans.
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Trends Biochem Sci,
1983]
In the course of metazoan development, the generation of multiple cell types from a single cell requires the repeated creation of daughter cells that differ from one another. This production of non-equivalent daughter cells can be called a developmental decision, or switch. The task of understanding development is that of determining how these switches are arranged in space and time, and then how they operate at a molecular level.