title: Characterisation of haemolytic activity from Aeromonas caviae.
abstract: Aeromonas caviae, an enteropathogen associated with gastroenteritis, displays several virulence characteristics. Studies on the kinetics of growth of A. caviae and expression of beta-haemolytic toxin revealed that A. caviae produced maximum haemolytic activity extracellularly during the stationary phase. Preliminary studies on the properties of A. caviae haemolysin suggested that divalent cations (Mg2+ and Ca2+) and thiol compounds, dithiothreitol and mercaptoethanol enhanced the haemolytic activity. Addition of L-cysteine, glutathione and EDTA reduced the haemolytic activity. The iron chelator, 2-2' bipyridyl, significantly inhibited the growth of A. caviae possibly by iron limitation, with parallel enhancement of haemolysin production compared to A. caviae grown in excess of iron. These results suggest that A. caviae produces only beta-haemolysin, which resembles the haemolysins reported for several other bacteria and the activity might be regulated by environmental factors especially iron.
authors.affiliation: Madurai Kamaraj University, India.
authors.forename: T
authors.initials: T
authors.lastname: Karunakaran
authors.forename: B G
authors.initials: BG
authors.lastname: Devi
mesh_terms: D015082:2,2'-Dipyridyl; D000333:Aeromonas / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D001427:Bacterial Toxins / Q000096:biosynthesis*; D002118:Calcium; D002455:Cell Division; D003470:Culture Media; D003545:Cysteine; D004229:Dithiothreitol; D004492:Edetic Acid; D005296:Ferrous Compounds; D005759:Gastroenteritis / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005978:Glutathione; D006460:Hemolysin Proteins / Q000096:biosynthesis*; D006801:Humans; D008274:Magnesium; D008623:Mercaptoethanol
chemical_list: D001427:Bacterial Toxins; D003470:Culture Media; D005296:Ferrous Compounds; D006460:Hemolysin Proteins; D015082:2,2'-Dipyridyl; D008623:Mercaptoethanol; D004492:Edetic Acid; D005978:Glutathione; D008274:Magnesium; D003545:Cysteine; C029451:ferrous chloride; D002118:Calcium; D004229:Dithiothreitol