Isolation and characterization of a virulent Lactobacillus sanfranciscensis bacteriophage and its impact on microbial population in sourdough.
Thirty-five sourdough samples used for sweet and salted Italian baked products were checked for the presence of a virus active on Lactobacillus sanfranciscensis species. One phage, named EV3, was isolated and its phenotypic and genotypic features were investigated. It belonged to the Siphoviridae family (morphotype B1); its life cycle at 25 degrees C lasted 3 h with a burst size of about 30 viral particles per infected cell. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed one major structural protein of 35 kDa and four minor proteins. The genome, approximately 32 kb long, was a double-stranded linear DNA molecule with a pac-type system. Phage spreading into sourdough did not adversely affect acidification and volume increase of the dough neither lactobacilli counts; the propagation of viral particles was shown to be hindered. This is the first report of the isolation of a L. sanfranciscensis phage.
Foschino
R
R
Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria, Milano 2 - 20133, Italy. roberto.foschino@unimi.it
Venturelli
E
E
Picozzi
C
C
D001433:Bacteriolysis; D001435:Bacteriophages / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D001939:Bread / Q000382:microbiology*; D015169:Colony Count, Microbial; D004247:DNA / Q000302:isolation & purification; D004279:DNA, Viral / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D007778:Lactobacillus / Q000821:virology*; D008854:Microscopy, Electron; D017906:Siphoviridae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology / Q000648:ultrastructure; D013696:Temperature; D013997:Time Factors; D010948:Viral Plaque Assay; D015678:Viral Structural Proteins / Q000032:analysis
D004279:DNA, Viral; D015678:Viral Structural Proteins; D004247:DNA