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[
Methods Cell Biol,
1995]
This chapter has two aims. First, we describe one method, the electropharyngeogram (EPG), insufficient detail that a Caenorhabditis elegans researcher unfamiliar with electrophysiological methods could set up the apparatus and get useful results. Second, we describe more generally for researchers familiar with electrophysiological methods how they may be applied to C. elegans. We do not describe methods for electrophysiological investigation of C. elegans sperm.
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[
1983]
The long-term goal of our research is the understanding of the molecular processes that control metazoan aging. We present background material that describes the past difficulties in isolating long-lived mutants and present our results describing the isolation of such long-lived variants. Some of these variants have life spans more than 60% longer than wild types. We point out the genetic advantages of C. elegans which may have made the isolation of these variants possible. We also present indirect data suggesting that, at least for a subclass of these variants, the differences in mean lifespan are ascribable to factors other than those mediated by genetically induced caloric restriction. We discuss the possibility that these factors involve an alteration of what has been termed the "rate of aging". We also discuss the genetic approach to the understanding of senescence.
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[
Lecture Notes in Computer Science,
2008]
One of the most tractable organisms for the study of nervous systems is the nematode Caenorhabditis elegans, whose locomotion in particular has been the subject of a number of models. In this paper we present a first integrated neuro-mechanical model of forward locomotion. We find that a previous neural model is robust to the addition of a body with mechanical properties, and that the integrated model produces oscillations with a more realistic frequency and waveform than the neural model alone. We conclude that the body and environment are likely to be important components of the worms locomotion subsystem.
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[
WormBook,
2005]
The C. elegans genome contains approximately 1300 genes that produce functional noncoding RNA (ncRNA) transcripts. Here we describe what is currently known about these ncRNA genes, from the perspective of the annotation of the finished genome sequence. We have collated a reference set of C. elegans ncRNA gene annotation relative to the WS130 version of the genome assembly, and made these data available in several formats.
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[
Methods Cell Biol,
1995]
A major tool of developmental genetics is the ordering of genes in functional pathways. In this chapter, we explain the logic behind constructing pathways, starting from the knowledge of the relevant phenotypes associated with the genes of interest, assuming that careful analysis of the phenotype has been carried out. We discuss the construction and interpretation of phenotypes of double mutants, screening for and analysis of extragenic suppressors, as well as issues regarding complex pathways and genetic redundancy. Avery and Wasserman (1992) have provided a brief theoretical discussion of epistasis analysis; here we explain the more practical aspects of how models of developmental pathways are built in
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[
WormBook,
2005]
Asymmetric cell divisions play an important role in generating diversity during metazoan development. In the early C. elegans embryo, a series of asymmetric divisions are crucial for establishing the three principal axes of the body plan (AP, DV, LR) and for segregating determinants that specify cell fates. In this review, we focus on events in the one-cell embryo that result in the establishment of the AP axis and the first asymmetric division. We first describe how the sperm-derived centrosome initiates movements of the cortical actomyosin network that result in the polarized distribution of PAR proteins. We then briefly discuss how components acting downstream of the PAR proteins mediate unequal segregation of cell fate determinants to the anterior blastomere AB and the posterior blastomere P 1 . We also review how a heterotrimeric G protein pathway generates cortically based pulling forces acting on astral microtubules, thus mediating centrosome and spindle positioning in response to AP polarity cues. In addition, we briefly highlight events involved in establishing the DV and LR axes. The DV axis is established at the four-cell stage, following specific cell-cell interactions that occur between P 2 and EMS , the two daughters of P 1 , as well as between P 2 and ABp , a daughter of AB . The LR axis is established shortly thereafter by the division pattern of ABa and ABp . We conclude by mentioning how findings made in early C. elegans embryos are relevant to understanding asymmetric cell division and pattern formation across metazoan evolution.
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[
Modeling in Molecular Biology. G Ciobanu and G Rozenberg (eds). Natural Computing Series, Springer-Verlag.,
2004]
We present preliminary results of a new approach to the formal modeling of biological phenomena. The approach stems from the conceptual compatibility of the methods and logic of data collection and analysis in the field of developmental genetics with the languages, methods and tools of scenario-based reactive system design. In particular, we use the recently developed methodology consisting of the language of live sequence charts with the play-in/play-out process, to model the well-characterized process of the cell fate acquisition during C. elegans
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[
1987]
One way to gain an understanding of any biological process is through the use of mutant analysis and selective breeding to generate stocks which have genetic alterations in that process. We have taken just this approach in the analysis of aging...
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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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[
1987]
We describe the use of a nonspecific carboxylesterase as a biochemical marker for intestinal differentiation in the nematode C. elegans. In particular, we describe how esterase expression responds to inhibition of embryonic DNA synthesis by aphidicolin. Esterase expression requires a short period of DNA synthesis immediattely after the gut lineage is clonally established. However, the subsequent 2-3 rounds of DNA synthesis, which normally occur before esterase gene transcription, can be inhibited without effect. Thus esterase expression depends neither on reaching the normal DNA:cytoplasmic ration nor on counting the normal number of replication rounds.