Studies on a Temperature-sensitive Irreparable Mutant of <i>Neurospora Crassa</i>

The Isolation and Characterization of Mutants of Bacillus subtilis and Bacillus licheniformis with Disturbed Morphology and Cell Division

“…Whatever these substances are, they would appear to be necessary for the orderly construction and division of the bacilli. If this is the true explanation, then the effect of salts might be an osmotic remedial effect like those reported for Neurospora crassa (Kuwana, 1961 ;Metzenberg, 1968) and Saccharornyces cerevisiae (Hawthorne & Friis, 1964;Baesel & Douglas, 1968) in which genetic defects were reversed by low molecular weight substances in the growth medium. The mechanism is not known; the application of this hypothesis will be discussed in the succeeding paper (Rogers & McConnell, 1970), where it is shown that one of the mutants (rod-4) can be corrected by the presence of glutamate or glutamine in the medium.…”

Studies on a Temperature-sensitive Irreparable Mutant of <i>Neurospora crassa</i>. II

“…The possible nature of the defect in an irreparable mutant was discussed in the previous report (Kuwana, 1960). There are numerous possibilities.…”

“…The origin and general properties of strain b39a were described in the previous paper (Kuwana, 1960), and recapitulated briefly in the introduction. For determining the extent of growth, the mutant and parent strains were cultivated in 20 ml medium in 100 ml Erlenmeyer flasks.…”

“…In a previous report (Kuwana, 1960), the present author described the origin and the fundamental characteristics of the temperature-sensitive irreparable mutant b39a of Neurospora crassa. Mutant b39a was obtained from microconidial prototrophic strain ma after nitrogen mustard treatment of the microconidia.…”

Physiological and genetic responses of bacteria to osmotic stress.

“…Mutations of this type are common; Hawthorne and Friis (90) found that in Saccharomyces cerelvisiae, about 16% of all auxotrophic mutations were osmoremedial. Usually, the phenotypic defect in osmoremedial mutants can be overcome by any nontoxic solute (16,20,66,77,90,128,155,162,166,228,247,262). However, in contrast to the findings of all other researchers, Kohno and Roth (124) reported that only ionic solutes could overcome the defect in osmoremedial his mutants of S. typhimur-iian.…”