title: Inhibition of biosynthesis of metalloprotease of Aeromonas sobria by sodium chloride in the medium.
abstract: The present authors have previously shown that the serine protease activity of Aeromonas sobria is markedly decreased when A. sobria is cultured in medium containing 3.0% sodium chloride (NaCl, concentration almost equivalent to sea water salinity), and that this occurs because, although the synthesis of ASP is not disturbed by the salt in the medium, the maturation pathway of serine protease of A. sobria (ASP) does not proceed successfully in such a medium. In this study, the effect of salt in the medium on the production of metalloprotease by A. sobria (AMP) was examined. A. sobria produced AMP in the milieu when the bacteria were cultured in medium containing (NaCl) at a concentration of 0.5%. However, AMP was not produced when the bacteria were cultured in salty medium containing 1.5% or more NaCl. To examine how NaCl reduces the production of metalloprotease by A. sobria, the amount of amp mRNA in the cell was measured and it was found that this decreased in proportion to the concentration of NaCl in the medium. The mRNA of amp was not detected in cells cultured in medium containing 1.5% or more NaCl. This means that the transcription of amp is inhibited in salty condition. As described, NaCl in the medium disturbs the maturation pathway of ASP. The mode of action whereby NaCl suppresses AMP activity in A. sobria differs from the mechanism for suppressing ASP activity.
authors.affiliation: Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Kitaku, Okayama, Japan. takahashi@pharm.okayama-u.ac.jp
authors.forename: Eizo
authors.initials: E
authors.lastname: Takahashi
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamanaka
authors.forename: Gopinath Balakrish
authors.initials: GB
authors.lastname: Nair
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Takeda
authors.forename: Sakae
authors.initials: S
authors.lastname: Arimoto
authors.forename: Tomoe
authors.initials: T
authors.lastname: Negishi
authors.forename: Keinosuke
authors.initials: K
authors.lastname: Okamoto
mesh_terms: D000333:Aeromonas / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001427:Bacterial Toxins / Q000096:biosynthesis; D003470:Culture Media; D045726:Metalloproteases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D052899:Pore Forming Cytotoxic Proteins / Q000096:biosynthesis; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D001427:Bacterial Toxins; D003470:Culture Media; D052899:Pore Forming Cytotoxic Proteins; D012965:Sodium Chloride; C032676:aerolysin; D045726:Metalloproteases