Regulation of Intracellular and Extracellular Neutral and Alkaline Proteases in Aspergillus nidulans

Abstract

S U M M A R YSynthesis and secretion of extracellular neutral and alkaline proteases in Aspergillus nidulans are repressed in the presence of low molecular weight sources of carbon, nitrogen and sulphur; protease is formed and released when the medium is deficient for any one of these elements. Induction of protease by exogenous protein does not occur.Activation of intracellular protease is repressed by sources of carbon, nitrogen, sulphur and phosphorus, activation taking place when any one is deficient.These two systems of repression are independent of one another and of the two previously defined systems of ammonium repression in Aspergillus nidulans. Several classes of mutant selected for ammonium derepression also have abnormal carbon repression of protease.

The Role of Proteins in the Nitrogen Nutrition of Ectomycorrhizal Plants

“…In view of the fact tbat production of proteolytic enzymes is subject to catabolite repression it might be predicted that the presence of free carbon would inhibit proteolytic activity. However, in studies of protein production by Aspergillus Cohen (1973) showed that the enzymes were secreted when the growth medium was deficient in any one of the low molecular weight sources of C, N and S. In the present case induction of enzyme production may be attributable to the absence of N compounds of low molecular weight. 'Starter' carbon may be required as an energy source for enzyme synthesis or as a component of the molecular structure of the enzyme.…”

Production of alkaline protease by a genetically engineered Aspergillus oryzae U1521.

“…The production of proteases appeared to be subjected to control easily ei-100 SAMARNTARN, CHEEVADHANARAK, and TANTICHAROEN Vol. 45 ther by metabolites repression/derepression or proteinaceous induction, or by the combination of both in several fungi (Cohen, 1973;Cohen et al, 1975;Farley and Ikasari, 1992;Lasure, 1980;North, 1982). Thus it is likely that the high production of alkaline protease in BDS medium involved the slow hydrolyzation and/or the proteinaceous component(s) of defatted soybean.…”

Disruption of Three Acid Proteases in Aspergillus Niger— Effects on Protease Spectrum, Intracellular Proteolysis, and Degradation of Target Proteins

“…Putative disruptants were identified using a PCR screening technique; spores were inoculated in 2 ml complete medium and the cultures were incubated overnight at 30°C. The mycelial mat was harvested, freeze dried, and dissolved in an extraction buffer described by de Graaff et al (1988). After phase separation, 10 pl of the liquid phase was used for PCR reactions using a Sensa 949E PCR apparatus and PCR conditions were those recommended for Taq polymerase (Pharmacia).…”

“…A. niger chromosomal DNA was isolated according to de Graaff et al (1988), digested with restriction enzymes, separated by agarose gel electrophoresis on 0.8 % (mass/vol.) agarose, and blotted onto a nylon membrane (Hybond N') via capillary elution according to Sambrook et al (1989).…”

“…The genetics of proteolytic degradation in Aspergilli is very complex due the involvement of many regulatory factors in protease expression. Cohen (1972Cohen ( , 1973 showed in a series of pioneering studies that in A. niduluns extracellular proteases were repressed by low-molecular-mass sources of carbon, nitrogen, and sulphur. and van den Hombergh et al (1994) have recently shown that in A. niger both pathway-specific induction by proteins and wide domain regulatory mechanisms (carbon catabolite repression, nitrogen metabolite repression, and pH regulation) are involved in the overall regulation of extracellular proteases.…”