[
1998]
The free-living nematode Caenorhabditis elegans has emerged rapidly as an organism with which to study many basic biological phenomena, particularly those related to development. This can ben evidenced numerically in many ways; for example, the number of presentations at the biennial C. elegans meeting has increased over sevenfold, from 80 in 1979 to 569 in 1995. In addition to numerous review articles, several books are devoted to this nematode, its attributes and various foci of interest. The three preliminary attributes that have rendered C. elegans a popular model system are overviewed briefly in the following three sections. The attributes that have rendered C. elegans popular with developmental biologists have also been exploited to examine specific areas in radiation biology, DNA repair, and mutagenesis. Several of the basic DNA repair pathways operative in C. elegans have been elucidated. Also, a number of biological end points such as survival and mutagenesis, have been examined so as to address the various mechanisms by which C. elegans accommodates DNA damage. Central to these efforts has been the isolation and characterization of radiation-sensitive (rad) mutants that modify various biological responses. In particular, these studies provide insights into damage processing, particularly as related to development and aging.
[
2000]
Computer tracking of Caenorhabditis elegans, a free-living soil nematode, is a promising tool to assess behavioral changes upon exposure to contaminants. A short life cycle, a known genetic make-up, thoroughly studied behavior, and a completely mapped nervous system make C. elegans an attractive soil test organism with many advantages over the commonly used earthworm. Although many toxicity tests have been performed with C. elegans, the majority focused on mortality, a much less sensitive endpoint than behavior. A computer tracking system has been developed to monitor behavioral changes using C. elegans. Because conditions unrelated to specific toxicant exposures, such as changes in temperature, developmental stage, and presence of adequate food sources, can affect behavior, there is a need to standardize tracking procedures. To this end, we have developed reference charts for control movement comparing the movement of four and five day-old adult nematodes. The use of K-medium versus deionized (DI) H2O for pre-tracking rinses was also investigated. A final reference chart compared the behavioral responses of nematodes at various food densities (i.e. bacterial concentrations).