Sequential Ascus Collection in Neurospora crassa

Ascus Formation and Recombinant Frequencies in Neurospora Crassa.

A NUMBER of years ago it became feasible, as a result of the development of a plating method (LEIN, MITCHELL and HOULAHAN 1948) to obtain prototroph frequencies in samples of several thousand spores from crosses between nutritional mutants. Previously, with a more laborious method, samples of a few hundred spores, or less, had usually formed the basis of linkage information. If linkage is at al...

Dominance modifiers in neurospora crassa: phenocopy selection and influence of certain ascus mutants.

When homozygous in zygotes, mutant alleles at the peak locus in linkage group V of Neurospora crassa initiate aberrant asci that are nonlinear, in contrast to the linear asci characteristic of wild type. Most mutant alleles are recessive, inasmuch as crosses of the mutant strains with wild type give linear asci. However, five different mutant alleles, when heterozygous with the wild-type allele...

Quelling in Neurospora crassa.

Heterocaryosis in Neurospora Crassa.

T IS possible by means of X-ray or ultraviolet treatment to produce mutant I strains of Neurospora crassa that are deficient in their abilities to synthesize specific vitamins, amino acids, or other essential substances (BEADLE and TATUM 1941; TATUM and BEADLE 1g4zb). It occurred to us that it might be possible to determine whether the mutant genes concerned in such haploid strains are recessiv...

Biotransformation of Hydrocortisone by Neurospora crassa

The ability of Neurospora crassa FGSC 4335 in the biotransformation of hydrocortisone was investigated. The microorganism produced two major metabolites after incubation with the substrate for seven days. Each microbial product was purified chromatographically and identified on the basis of spectral data. The products were identified as 11?,17?,20?,21-tetrahydroxypregn-4-en-3-one (II) and 11?-h...