title: Identification and partial characterization of an Actinomyces pyogenes hemolysin.
abstract: Twenty-two Actinomyces pyogenes isolates were recovered from hepatic abscesses in cattle and evaluated for hemolysin production. Hemolysin was collected from supernatant of cultures grown in 6% CO2 in brain heart infusion (BHI) broth. The effect of oxidizing and reducing agents, enzymes, temperatures and pH on hemolytic activity were studied using sheep erythrocytes as the target cells. Our study showed that A. pyogenes hemolysin is oxygen stable; sensitive to treatment by protease, trypsin, and amylase; and destroyed by treatment at extreme temperatures (56 and 100 degrees C) and pH (pH 3 and 11). Production of hemolysin was studied in BHI, RPMI-1640, and a defined serum-free A. pyogenes medium under aerobic and anaerobic conditions. Maximum hemolysin was produced in BHI incubated aerobically in 6% CO2 and to a lesser degree anaerobically in RPMI-1640. No hemolysin was produced in the defined A. pyogenes medium. Differential filtration, isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis identified two hemolysin proteins with pI values of 3.40 and 9.45 and estimated molecular masses of 62 and 58 kDa, respectively. Cell-free supernatant samples positive for hemolysin activity also were screened for leukotoxin activity. Significant levels of leukotoxin were detected in all samples screened.
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5605, USA.
authors.forename: P G
authors.initials: PG
authors.lastname: Funk
authors.forename: J J
authors.initials: JJ
authors.lastname: Staats
authors.forename: M
authors.initials: M
authors.lastname: Howe
authors.forename: T G
authors.initials: TG
authors.lastname: Nagaraja
authors.forename: M M
authors.initials: MM
authors.lastname: Chengappa
mesh_terms: D000190:Actinomyces / Q000378:metabolism*; D000196:Actinomycosis / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D003470:Culture Media; D004798:Enzymes / Q000494:pharmacology; D006460:Hemolysin Proteins / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008100:Liver Abscess / Q000382:microbiology / Q000662:veterinary*; D010084:Oxidation-Reduction; D013696:Temperature; D013997:Time Factors
chemical_list: D003470:Culture Media; D004798:Enzymes; D006460:Hemolysin Proteins