A diffusible bacterial product suppresses life span extension by bacterial deprivation (BD) in C. elegans. (A) Animals cultured on plates treated with cell-free supernatant from an overnight culture of E. coli OP50 (BD + sup) had decreased survival compared to animals maintained on untreated BD plates or BD plates treated with uninoculated LB (BD + LB). The life span of the treated group was still longer than that of control fed (CF) animals. (B) An alternate experimental strategy to exposing animals on BD to bacterial products in the absence of food consumption is to use agar barrier plates, in which a bacterial lawn is separated from the worms by a layer of agar (see Methods for a detailed description). (C) Animals cultured on agar barrier plates had decreased survival compared to animals maintained on BD plates with no bacteria present. Number of animals examined, mean life spans ± standard error, median life span, and statistical significance are provided in Table 5A. Extended statistical analysis (pair-wise comparisons) is provided in Table 5B.
Smith et al. BMC Developmental Biology 2008 8:49 doi:10.1186/1471-213X-8-49