title: Production of thiol-dependent haemolysins by Listeria monocytogenes and related species.
abstract: Twenty-six strains belonging to the five main species of the genus Listeria were examined for production of thiol-dependent exotoxins. All strains of L. monocytogenes cultured in charcoal-treated broth secreted a haemolytic factor at a level ranging from 200 to 800 haemolytic units (HU) ml-1, except for the strain EGD (1500 HU ml-1) and the type strain CIP 82110T (10 HU ml-1). The haemolytic activity reached a maximum level by 8-10 h and then rapidly declined as soon as bacterial exponential growth ceased. The titres of haemolytic activity were markedly reduced when bacteria were grown in charcoal-untreated broth. The haemolytic factor produced by L. monocytogenes strains was characterized as listeriolysin O (Mr about 60,000), a member of the group of thiol-dependent exotoxins. Strains of Listeria ivanovii also produced high levels of thiol-dependent exotoxin (about 2500 HU ml-1), in both charcoal-treated and untreated broth. Small amounts of haemolytic factor (about 9-30 HU ml-1) were also produced by Listeria seeligeri in charcoal-treated broth. The haemolysin produced by L. seeligeri was identified for the first time as a thiol-dependent exotoxin of Mr about 60,000, antigenically related to listeriolysin O. As expected, we failed to detect thiol-dependent exotoxin in the two nonhaemolytic species, Listeria innocua and Listeria welshimeri.
authors.affiliation: Unité des Antigènes Bactériens (Centre National de la Recherche Scientifique, UA 040557), Institut Pasteur, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Geoffroy
authors.forename: J L
authors.initials: JL
authors.lastname: Gaillard
authors.forename: J E
authors.initials: JE
authors.lastname: Alouf
authors.forename: P
authors.initials: P
authors.lastname: Berche
mesh_terms: D006460:Hemolysin Proteins / Q000096:biosynthesis*; D006461:Hemolysis; D015151:Immunoblotting; D008087:Listeria / Q000254:growth & development / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D006460:Hemolysin Proteins; D013438:Sulfhydryl Compounds