title: Characterization of an antimicrobial peptide produced by Bacillus subtilis subsp. spizezinii showing inhibitory activity towards Haemophilus parasuis.
abstract: Haemophilus parasuis is the pathogen that causes Glässer's disease, a major illness affecting young pigs. The aim of this work was to investigate the antagonistic activity of antimicrobial substances produced by Bacillus species against H. parasuis. Among the tested strains, only Bacillus subtilis ATCC 6633 inhibited H. parasuis growth. The antibacterial substance was purified by ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-50 and ion-exchange chromatography on DEAE-cellulose. The purification was about 100-fold with a yield of 0.33 %. The purified substance was resistant up to 80 °C and pH ranging 3-7, but the substance lost its activity when it was treated with proteases. The peptide had a molecular mass of 1083 Da and its sequence was determined by MS as NRWCFAGDD, which showed no homology with other known antimicrobial peptides. The complete inhibition of H. parasuis growth was observed at 20 µg peptide ml(-1) after 20 min of exposure. The peptide obtained by chemical synthesis also showed antimicrobial activity on H. parasuis. The identification of antimicrobial substances that can be effective against H. parasuis is very relevant to combat this pathogen that causes important losses in swine production.
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brasil.
authors.forename: Mário Lettieri
authors.initials: ML
authors.lastname: Teixeira
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brasil.
authors.forename: Andréia Dalla
authors.initials: AD
authors.lastname: Rosa
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brasil.
authors.forename: Adriano
authors.initials: A
authors.lastname: Brandelli
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000737:chemistry / Q000378:metabolism*; D044137:Haemophilus parasuis / Q000187:drug effects* / Q000502:physiology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides