Extracellular proteases of Aspergillus flavus. Fungal keratitis, proteases, and pathogenesis.
To get a better understanding of the possible role of proteases in the pathogenesis of fungal keratitis, the extracellular proteases of a clinical isolate of Aspergillus flavus, from a severe case of keratitis, were identified and partially characterized. This strain, designated CU226/88, was grown with a variety of substrates as nitrogen sources, under conditions that would be expected to derepress the production of extracellular proteases. When grown on minimal medium with milk protein as a nitrogen source, the fungus appeared to produce primarily a metalloprotease, which has a zinc cofactor. When grown with insoluble collagen or elastin as a nitrogen source, a serine protease and cysteine protease, as well as the metalloprotease, are produced. Strain CU226/88 can grow with collagen, but not elastin, as the sole source of carbon as well as nitrogen. It is possible that the collagenase activity is a mediator of the severe corneal destruction caused by this isolate.
Zhu
W S
WS
Department of Biophysics, University of Rochester, School of Medicine, New York.
Wojdyla
K
K
Donlon
K
K
Thomas
P A
PA
Eberle
H I
HI
D001228:Aspergillosis / Q000382:microbiology*; D001231:Aspergillus flavus / Q000201:enzymology* / Q000254:growth & development; D002364:Caseins / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D003320:Corneal Ulcer / Q000382:microbiology*; D003470:Culture Media; D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D004549:Elastin / Q000378:metabolism; D010450:Endopeptidases / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D015821:Eye Infections, Fungal / Q000382:microbiology*; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D003012:Microbial Collagenase / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D008875:Middle Aged; D008970:Molecular Weight; D010196:Pancreatic Elastase / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism
D002364:Caseins; D003470:Culture Media; D011480:Protease Inhibitors; C026018:azocasein; D003094:Collagen; D004549:Elastin; D010450:Endopeptidases; D012697:Serine Endopeptidases; D010196:Pancreatic Elastase; D003546:Cysteine Endopeptidases; D008666:Metalloendopeptidases; D003012:Microbial Collagenase