Heat stability of virulence-associated enzymes from Listeria monocytogenes SLCC 5764.
The enzyme activities of listeriolysin O (LLO), phosphatidylinositol-specific phospholipase C (PI-PLC), catalase (CA), and superoxide dismutase (SOD) from Listeria monocytogenes SLCC 5764 were examined after heat treatment, growth at elevated temperatures, and anaerobic growth. Growth at elevated temperatures may influence virulence as expressed by virulence enzyme activity. The enzymes were heated for 0 and 10 min at temperatures ranging from 40 to 100 degrees C. The production of LLO was examined when the bacterium was grown at elevated temperatures, and the production of LLO, CA, and SOD were examined after anaerobic growth. LLO was the most heat-labile factor, losing almost all activity when heated above 50 degrees C. CA was more heat stable, showing no decrease in activity until it was heated at 55 degrees C. The PI-PLC enzyme was most heat resistant: the activity decreased between 40 and 50 degrees C and continued to decrease when heated between 65 and 100 degrees C. When L. monocytogenes was grown at elevated temperatures, it produced less LLO than when grown at the optimum growth temperature of 37 degrees C. When the organism was grown under anaerobic conditions, the levels of CA and LLO decreased, while the SOD level remained unchanged.
University of Illinois, Department of Food Science and Human Nutrition, Urbana 61801, USA.
R B
RB
Zemser
S E
SE
Martin
D001427:Bacterial Toxins; D002374:Catalase / Q000378:metabolism; D004795:Enzyme Stability; D006360:Heat-Shock Proteins / Q000378:metabolism; D006460:Hemolysin Proteins; D006358:Hot Temperature; D008089:Listeria monocytogenes / Q000201:enzymology* / Q000472:pathogenicity; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D013482:Superoxide Dismutase / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism; D014774:Virulence
D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D002374:Catalase; D013482:Superoxide Dismutase; D010738:Type C Phospholipases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; C038705:hlyA protein, Listeria monocytogenes