Activation of cyclic AMP phosphodiesterase I by brain or Neurospora calmodulin was studied. The stimulation required micromolar concentrations of Ca2+, and it was observed at cyclic AMP concentrations between 0.1 and 500 microM. Activation was blocked by EDTA and some neuroleptic drugs such as chlorpromazine and fluphenazine. These drugs inhibit the elongation of N. crassa wild-type aerial hyph...

The photodynamic effect of polycyclic hydrocarbons was studied in Neurospora crassa and tissue culture cells of the Chinese hamster. The polycyclic hydrocarbons were dissolved in dimethylformamide and added to the treatment solution or medium. Other solvents, such as dimethyl sulfoxide and bovine serum, quenched the photodynamic effect of 3,4-benzpyrene and could not be used. Conidia from a dik...

A new strain of Neurospora crassa which exhibits a rhythm of conidiation when growing along an agar surface in a growth tube is described. The rhythm has been shown to be circadian for it meets the following criteria: A) the period under constant environmental conditions in the dark is about 24 hours (22.7 hours at 25 degrees ); B) the period is relatively temperature-independent (Q(10) is betw...

N Neurospora crassa, as in other ascomycetes with a spreading type of I growth, it has been necessary to obtain genetic data by the laborious method of isolating single ascospores in test tubes, and, in the case of biochemical mutants, transferring each of the cultures thus obtained to various media in order to characterize it (BEADLE 1945). The discovery that sorbose and certain other agents w...

Two newly isolated mutant strains of Neurospora crassa, cpz-1 and cpz-2, were hypersensitive to chlorpromazine with respect to mycelial growth but responded differently to the drug with respect to the circadian conidiation rhythm. In the wild type, chlorpromazine caused shortening of the period length of the conidiation rhythm. Pulse treatment with the drug shifted the phase and inhibited light...

Neurospora crassa, the filamentous fungus possesses widest array of genome defense mechanisms known to any eukaryotic organism, including a process called repeat-induced point mutation (RIP). RIP is a genome defense mechanism that hypermutates repetitive DNA sequences; analogous to genomic imprinting in mammals. As an impact of RIP, Neurospora possesses many fewer genes in multigene families th...

In the Neurospora circadian negative feedback loop, white collar 1 (WC-1) and WC-2 form the WC complex that activates frequency (frq) transcription. Here we show that Not1 is a WC-interacting protein and is important for maintaining WC levels. The not1 transcript displays a circadian oscillation with a similar phase as frq. Down-regulation of not1 leads to low levels of WC-1 and WC-2 and a dela...

We have outlined a procedure that allows the large-scale screening of mutagenized Neurospora crassa populations for invertaseless mutants. We have isolated and characterized three mutations, inv(DBL1), inv(DBL9) and inv(DBL14), which have been mapped at or near the invertase structural gene. One of these, inv(DBL1), is particularly interesting. Our experiments indicate that the reduced level of...

N earlier studies with Neurospora, it was believed that with biochemical I mutants the heterocaryon test was a satisfactory test for allelism, based on the expectation that only heterocaryons between nonallelic mutants should be capable of growth on nonsupplemented media (BEADLE and COONRADT 1944). However, experiments by MITCHELL and MITCHELL (1956) suggested that a positive heterocaryon test ...