Relationship Between the Axenic Phenotype and Sensitivity to  -Aminocarboxylic Acids in Dictyostelium discoideum

Abstract

A previous suggestion that sensitivity to o-aminocarboxylic acids in Dictyostelium discoideum is associated with the ability to grow axenically has been re-evaluated using new axenic strains and axenic derivatives of strain AX^ recombinant for linkage group 11. It is now shown that the major gene for o-aminocarboxylic acid sensitivity, designated oaaA, is not allelic to previously described axenic loci axeA and axeB, but that oaaA is closely linked to, or allelic with a third axenic gene axeC found in strains AX2 and AX^. The axeC phenotype is rapid growth in axenic medium. The oaaA locus is located on linkage group 11. Genetic evidence suggests that the strains AX2 and AX3 now in existence share a common genetic background and may not represent independent isolates from the wild-type strain N C~. Studies with 14C-labelled c-aminocaproic acid show that sensitivity to o-aminocarboxylic acids is correlated with increased myxamoebal permeability to these compounds.

Examination of the Chromosomes of Polysphondylium pallidum Following Metaphase Arrest by Benzimidazole Derivatives and Colchicine

“…However, it is likely that the axenic growth of P. pallidum requires at least one mutation, since strains which were obtained after axenic growth and then passaged on bacteria grew immediately upon re-inoculation into axenic medium; that is, the axenic strains appear to be genetically different from their parents. Recent studies on D. discoideum suggest at least three mutations are involved with rapid axenic growth in this species (North & Williams, 1978).…”

Intercellular communication in the multicellular stage of Dictyostelium discoideum

“…NP84 is a mutant strain originally isolated as being temperature sensitive for growth [17]; subsequently, it was shown that NPM slugs migrate for unusually long periods before they form fruiting bodies [24], a finding confirmed by ourselves. NP84 is a mutant strain originally isolated as being temperature sensitive for growth [17]; subsequently, it was shown that NPM slugs migrate for unusually long periods before they form fruiting bodies [24], a finding confirmed by ourselves.…”

“…Tip regeneration in NP84 slugs is significantly slower than that in NC4 slugs. NP84 is a mutant strain originally isolated as being temperature sensitive for growth [17]; subsequently, it was shown that NPM slugs migrate for unusually long periods before they form fruiting bodies [24], a finding confirmed by ourselves. Table 1 shows that, following amputation at any level, NP84 slugs take markedly longer than NC4 slugs to regenerate a new tip.…”

“…The details of the media used as well as the techniques employed for growing and maintaining cells, inducing the transition from feeding to aggregation, monitoring slugs, amputating tips, grafting tips and scoring for regeneration or graft rejection have bean described previously [15]. The two haploid strains of D. discoideum used were NC4 (our usual wild type) and NP84, a mutagenised derivative of the wild type V12 strain [17]. NP84 carries genes both for axenic growth as well as for temperature sensitivity to growth at high temperature (27" C); the growth of NC4 is unimpaired both at standard laboratory temperatures (21"-23" C) and at 27" C. Spores of NP84 were a kind gift from Dr. K. Williams (Max-Planck-Institut, Munich); the strain was subsequently maintained by routine subculture and periodic cloning.…”

Mutations specific to spore maturation in the asexual fruiting body of dicytostelium discoideum

“…We have observed that the spores of some AX3-derived strains survive poorly on silica gel. AX2 and AX3 are probably very closely related strains [20]. Spores of strain NP170, an AX3-derived strain, and particularly cobalt resistant strains derived from it [21], have spores that have a similar phenotype to the sprJ mutants described here.…”