A cyclic adenosine 3?,5?-monophosphate-dependent protein kinase mutant of Neurospora crassa

Does the second messenger cAMP have a more complex role in controlling filamentous fungal morphology and metabolite production?

The effect of second messenger cAMP on the physiological aspects of fungal cells such as pigmentation has been reported previously. However, their actual role in the cellular biochemical cascade that eventually affects the fungal growth morphology, such as mycelial pellet formation, is unclear. This article intends to open up the detailed study on the possible correlative effect of cAMP on the morphological and physiological growth aspects of filamentous fungi, with special emphasis on the industrial metabolite production.

Filamentous ascomycetes fungi as a source of natural pigments

Filamentous fungi, including the ascomycetes Monascus, Fusarium, Penicillium and Neurospora, are being explored as novel sources of natural pigments with biological functionality for food, feed and cosmetic applications. Such edible fungi can be used in biorefineries for the production of ethanol, animal feed and pigments from waste sources. The present review gathers insights on fungal pigment production covering biosynthetic pathways and stimulatory factors (oxidative stress, light, pH, nitrogen and carbon sources, temperature, co-factors, surfactants, oxygen, tricarboxylic acid intermediates and morphology) in addition to pigment extraction, analysis and identification methods. Pigmentation is commonly regarded as the output of secondary protective mechanisms against oxidative stress and light. Although several studies have examined pigmentation in Monascus spp., research gaps exist in the investigation of interactions among factors as well as process development on larger scales under submerged and solid-state fermentation. Currently, research on pigmentation in Neurospora spp. is at its infancy, but the increasing interest for biorefineries shows potential for booming research in this area.

Isolation and characterization of the adenylate cyclase structural gene of Neurospora crassa

A single gene (nac) encoding an adenylate cyclase was cloned from the genomic DNA library of Neurospora crassa, using the DNA fragment encoding the catalytic domain of adenylate cyclase of Saccharomyces cerevisiae as a probe. The open reading frame of this gene (6900 base pairs) was interrupted three time by introns. The protein encoded consists of 2300 amino acids and has adenylate cyclase activity. N. crassa adenylate cyclase has a high degree of homology with the catalytic domains of yeast and bovine brain adenylate cyclases.

Suppression of the cr-1 mutation in Neurospora crassa

We have cloned a DNA fragment, which hybridized with the adenylate cyclase gene (CYR1) of Saccharomyces cerevisiae, from genomic DNA libraries of Neurospora crassa. The cr-1 mutation was able to be suppressed by introducing this DNA fragment on a cosmid vector, judging from recovery of the adenylate cyclase activity and the abnormal morphology.

Light-stimulated phosphorylation of proteins in cell-free extracts from Trichoderma viride

When illuminated by visible light, cell-free extracts from the fungus Trichoderma viride catalysed the phosphorylation of at least two proteins with molecular masses of 18 and 114 kDa which were practically absent when the phosphorylation was performed in the dark. The effect of light could be substituted by 3mM cyclic AMP, not only in the cell-free extract, but also in the separated cytosol. It is concluded that the process of photoinduced conidiation in Trichoderma involves phosphorylation of conidiation-specific proteins by (a) cyclic AMP-dependent protein kinase(s) present in the cytosol.