title: Properties of hemolysin and protease produced by Aeromonas trota.
abstract: We examined the properties of exotoxins produced by Aeromonas trota (A. enteropelogenes), one of the diarrheagenic species of Aeromonadaceae. Nine of 19 A. trota isolates that grew on solid media containing erythrocytes showed hemolytic activity. However, the hemolytic activities of the culture supernatants of these hemolytic strains of A. trota were markedly lower than those of A. sobria when cultured in liquid medium, and the amount of hemolysin detected by immunoblotting using antiserum against the hemolysin produced by A. sobria was also low. A mouse intestine loop assay using living bacterial cells showed that A. trota 701 caused the significant accumulation of fluid, and antiserum against the hemolysin produced suppressed the enterotoxic action of A. trota 701. These results indicated that A. trota 701 was diarrheagenic and the hemolysin produced was the causative agent of the enterotoxic activity of A. trota. The hemolysin in A. sobria was previously shown to be secreted in a preform (inactive form) and be activated when the carboxy-terminal domain was cleaved off by proteases in the culture supernatant. Since mature hemolysin was detected in the culture supernatants of A. trota, we analyzed the extracellular protease produced by A. trota. Fifteen of 19 A. trota isolates that grew on solid media containing skim milk showed proteolytic activity. We subsequently found that most A. trota isolates possessed the serine protease gene, but not the metalloprotease gene. Therefore, we determined the nucleotide sequence of the serine protease gene and its chaperone A. trota gene. The results obtained revealed that the deduced amino acid sequences of serine protease and the chaperone were homologous to those of A. sobria with identities of 83.0% and 75.8%, respectively.
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
authors.forename: Eizo
authors.initials: E
authors.lastname: Takahashi
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Ozaki
authors.affiliation: Course of Clinical Pharmacy, Yokohama College of Pharmacy, Yokohama, Kanagawa, Japan; Institute of Pharmacognosy, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro, Tokushima, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Fujii
authors.affiliation: Laboratory of Molecular Microbiological Science, Faculty of Pharmaceutical Sciences, Hiroshima International University, Kure, Hiroshima, Japan.
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Laboratory of Molecular Microbiological Science, Faculty of Pharmaceutical Sciences, Hiroshima International University, Kure, Hiroshima, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamanaka
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Arimoto
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
authors.forename: Tomoe
authors.initials: T
authors.lastname: Negishi
authors.affiliation: Laboratory of Protein Function, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan.
authors.forename: Keinosuke
authors.initials: K
authors.lastname: Okamoto
mesh_terms: D000333:Aeromonas / Q000201:enzymology* / Q000378:metabolism* / Q000472:pathogenicity; D000818:Animals; D006460:Hemolysin Proteins / Q000378:metabolism*; D015151:Immunoblotting; D051379:Mice; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D006460:Hemolysin Proteins; D010447:Peptide Hydrolases