C. elegans worms develop at a reduced rate, achieve a thinner body size, and accumulate decreased intestinal fat deposits on TAN 31504 food source lawns. (A) Developmental progress of worms raised from eggs at 25°C on lawns of E. coli OP50-1, L. chromiireducens subsp. chromiireducens LMG 22506, and L. chromiireducens subsp. solipictus TAN 31504 generated on LB medium supplemented with cholesterol. Each growth condition (food source) assessed is listed on the x axis below the corresponding set of data. The percentage of worms that reached adulthood relative to the total number of worms assessed for the particular condition (black) and the percentage of gravid adults among that population (gray) are shown on the y axis for each time point. A developmental delay was observed for worms reared on LMG 22506 and TAN 31504 compared to OP50-1, with the most extensive delay in development occurring on TAN 31504. Only on OP50-1 did a majority (97%) of the worm population reach adulthood by 48 h (not shown). (B and D) DIC micrographs of age-matched young adult worms reared from eggs at 25°C in the presence of cholesterol on Nile red-containing TAN 31504 (B) and Nile red-containing standard food source lawns (D) (×200 magnification). The head of the worm is positioned down, and the vulva is located on the right exterior side of the mid-body region. The images are representative of the overall thinner body size TAN 31504-reared worms displayed compared to the average body size achieved by young adult worms raised on the standard food source. Magnified images of these worms are found in Fig. S4 in the supplemental material. (C and E) Corresponding N3 filter fluorescence micrographs of images shown in panels B and D, respectively. The white arrowhead points to the anterior region of the intestine. The fluorescence shows the Nile red-stained fat deposits of the worm intestinal cells. The images are representative of the general decrease in intestinal fat stores observed in worms raised on TAN 31504 compared to those accumulated by worms reared on the standard food source.