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Growth Conditions Affecting Proteolytic Enzyme and Extracellular Vesicle Production by Pseudomonas fragi ATCC 4973
Author(s) -
MYHARA ROBERT M.,
SKURA BRENT J.
Publication year - 1989
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1989.tb04682.x
Subject(s) - extracellular , vesicle , pseudomonadales , pseudomonadaceae , pseudomonas , chemistry , microbiology and biotechnology , proteolytic enzymes , agar plate , enzyme , agar , biochemistry , bacteria , biology , membrane , genetics
Pseudomonas fragi ATCC 4973 was grown in liquid culture (trypticase soy broth) and on a solid surface (tryticase soy broth + 1.5% agar). Pseudomonas fragi grown in liquid culture started extracellular proteolytic enzyme production at 24 hr, during the late exponential early stationary growth phase. Pseudomonas fragi, grown on solid surfaces, initiated proteinase production at 4 hr, 20 hr earlier than in liquid medium. Proteinase production was greatest during periods when the cells were not actively growing. Electron micrographs of P. fragi grown on solid surfaces revealed extracellular vesicles ca. 20 nm in diameter “blebbing” off the surface of the cells. The greatest number of vesicles coincided with maximum proteinase production. These vesicles were absent from the surface of P. fragi cells grown in liquid culture.