THE EFFECT OF TEMPERATURE ON THE PRODUCTION OF PERITHECIA BY NEUROSPORA CRASSA

The genetic control of protoperithecial production inSordaria brevicollis

Mutations have been detected which affect the production of protoperithecia inSordaria brevicollis. These mutations have been calledperithecial-1andperithecial-2. Ascus analysis revealed that the former was a centromere unlinked gene, whilst the latter was very close to the mating-type locus. Theper 1−per 2− genotype was female sterile. Recovery of fertility by a sterile culture occurred and perithecial analysis revealed that this recovery was due to the accumulation of revertantper 1+nuclei in the mycelium.Per l−per 2+colonies were fertile and gave a cross of characteristic appearance.

Conidia induce the formation of protoperithecia in Neurospora crassa: further characterization of white collar mutants

The treatment of undifferentiated mycelia with heavy suspensions of their own conidia triggers protoperithecial development. This effect was also observed with white collar (wc) mutants and suggests that the wc genes are not structural genes necessary for morphogenesis of protoperithecia but that they are probably involved in regulation.

Meiosis in protists. Some structural and physiological aspects of meiosis in algae, fungi, and protozoa

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Multiple alterations in metabolite uptake in a mutant of Neurospora crassa

A temperature-conditional lethal mutant of Neurospora crassa, un-t (55701), was resistant to neutral amino acid analogues by virtue of a decreased ability to transport these analogues and their natural congeners across the cell membrane. The uptake of acidic, but not basic, amino acids was also impaired, as was the uptake of potassium ions. After preincubation above the tolerated temperature, the ability to take up a still wider variety of metabolites was greatly reduced. Protoplasts of the mutant were more osmotically fragile than those of wild type. The possibility that the mutant has a generalized membrane defect is discussed.