Worm Breeder's Gazette 5(1): 22
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
The genes affecting dauer formation on NGM agar plates do not all act similarly in liquid culture. Strains carrying one allele of each of the dauer defective genes placed in the genetic pathway were tested in liquid culture for their ability to form dauer larvae when starved. Each strain was grown in shaking cultures of liquid worm medium (LWM) with E. coli strain NA22 (2X Stationary -- grown in 3XD(mod), washed 1X in LWM). Cultures were allowed to reach starvation and then were tested for dauer formation by 1% SDS (30 min) treatment of aliquots taken over three successive days. Levels of dauer formation either were similar to N2 controls, or else no dauers were found. Although none of the strains produce any dauers when similarly tested on NGM ( agar) medium the following results were obtained in liquid culture: mutants daf-3 (e1376), daf-5 (e1386). daf-10 (e1387) and daf-20 (m25) form dauers when starved in liquid culture. Mutants daf-6 (e1377), daf-12 (m20), daf-16 (m26), daf-17 (m27), and daf-18 (e1375) do not form dauers when starved in liquid. We conclude that there is a partially distinct pathway for dauer formation which functions in liquid culture, perhaps as a response to crowding. The majority of most dauer-defective mutants isolated as unable to form dauers on plates also block the 'liquid' pathway. However, a separate branch must be postulated because the expression of these genes in liquid culture does not fit the pattern of suppression which establishes the two branches of the pathway delineated by dauer-constitutive mutations. Perhaps dauer-constitutives affected in this branch of the pathway might be found by performing the mutant selection in liquid medium. Suppression of dauer-constitutive mutations by defectives has not been tested in liquid as yet.