The intestine cells of the nematode C. elegans show a light blue autofluorescence in live animals when observed under 350-400 nm ultraviolet light. Several years ago, Padmanabhan Babu, identified mutants with altered fluorescence of the gut cells, which range from light purple blue, to green, and very purple blue, and were named flu- 1,
flu-3, and
flu-4. Chromatographic analysis of the crude extracts from
flu-1 and
flu-2 mutants revealed that the mutants may have defects in the tryptophan catabolism (Babu, 1974, Siddiqui, and von Ehrenstein, 1980). Later it was biochemically confirmed that indeed
flu-1 mutants had reduced levels of the kynurenine hydroxylase enzyme that catalyzes the conversion of kynurenine into 3-hydroxy kynurenine (Siddiqui and Babu, 1980);and flu- 2 mutants were shown to have a block at the level of kynureninase, that catalyzes the conversion of kynurenine into anthranilic acid and alanine (Babu and Bhat, 1980, Siddiqui 1978). The biochemical defect in
flu-3 and
flu-4 mutants remain unknown. We have begun looking for the flu mutants in the mutator strains RW7097 and TR679 to isolate these mutations through transposon tagging method. In addition, we have isolated revertant of a
flu-2 mutant ( EMS induced), and analyzed anthranilic acid levels in N2 SQ201
flu-2 X mutant, and the revertant SQ202 strain fluorimetrecally. Surprisingly, the revertant shows much reduced levels of anthranilic acid as compared to the wild type and the
flu-2 mutant, as shown below. We are doing genetic mapping of the revertant gene. [See Figure 1]