title: Characterization of a bacteriocin produced by Streptococcus thermophilus ST134.
abstract: A pH-dependent adsorption/desorption technique was used to screen Streptococcus thermophilus strains for the production of bacteriocins. Agar-diffusion tests with S. thermophilus strains as targets identified 13 out of 41 strains as producers of antibacterial activity. Thermophilin A, the bacteriocin-like substance present in the culture supernatant of S. thermophilus ST134 was purified to homogeneity by ammonium sulfate precipitation and ion-exchange chromatography, followed by ultrafiltration. Thermophilin A is a relatively heat-stable and apparently glycosylated bacteriocin with a bactericidal mode of action against sensitive cells.
authors.affiliation: U.S. Department of Agriculture, ARS, Eastern Regional Research Center, Philadelphia, PA 19118, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Ward
authors.forename: G A
authors.initials: GA
authors.lastname: Somkuti
mesh_terms: D001430:Bacteriocins / Q000096:biosynthesis / Q000302:isolation & purification* / Q000494:pharmacology; D006023:Glycoproteins / Q000096:biosynthesis / Q000302:isolation & purification* / Q000494:pharmacology; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D013045:Species Specificity; D013291:Streptococcus / Q000737:chemistry*
chemical_list: D001430:Bacteriocins; D006023:Glycoproteins