Cuticle-degrading proteases from the entomopathogen Metarhizium flavoviride and their distribution in secreted and intracellular fractions.
OBJECTIVE
The aim of this study was to analyse a native isolate of Metarhizium flavoviride (CG423) which is being developed as a myco-insecticide against grasshoppers in Brazil for the production of the cuticle-degrading subtilisin-like (Pr1), and trypsin-like (Pr2) proteases.


RESULTS
The results show that Pr1 activity occurred only in medium supplemented with grasshopper cuticle (Schistocerca pallens). In contrast, Pr2 was detected in higher amounts on defined growth substrate than on cuticle-supplemented medium. Both activities were detected after 48 h of growth, suggesting that in S. pallens cuticle-containing medium these protease types are not co-ordinately expressed. Low levels of enzyme activity were detected when pre-grown mycelium was used to investigate the induction of Pr1 proteases.


CONCLUSIONS
The analysis of Pr1 and Pr2 distribution in both secreted and intracellular fractions revealed high percentage of extracellular activity, which may suggest the occurrence of an efficient mechanism of protein secretion by this fungus, probably related to substrate degradation which provides nutrients for fungal growth.
Tiago
P V
PV
Departamento de Microbiologia, Universidade Estadual de Londrina, Londrina/PR, Brazil.
Fungaro
M H P
MH
Furlaneto
M C
MC
D000818:Animals; D001203:Ascomycota / Q000201:enzymology* / Q000254:growth & development / Q000472:pathogenicity; D003470:Culture Media; D010450:Endopeptidases / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D006110:Grasshoppers / Q000382:microbiology*; D019476:Insect Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism; D020860:Subtilisin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
D003470:Culture Media; D005656:Fungal Proteins; D019476:Insect Proteins; C047663:cuticle proteins, insects; D010450:Endopeptidases; D012697:Serine Endopeptidases; C093192:pr1 protein, Metarhizium anisopliae; D014357:Trypsin; D020860:Subtilisin