title: Evidence for the presence of restriction/modification systems in Lactobacillus delbrueckii.
abstract: The bacteriophages Cb1/204 and Cb1/342 were obtained by induction from the commercial strain Lactobacillus delbrueckii subsp. lactis Cb1, and propagated on Lactobacillus delbrueckii subsp. lactis 204 (Lb.l 204) and Lactobacillus delbrueckii subsp. bulgaricus 342 (Lb.b 342), respectively. By cross sensitivity, it was possible to detect a delay in the lysis of Lb.l 204 with Cb1/342 phage, while the adsorption rate was high (99.5%). Modified and unmodified phages were isolated using phage Cb1/342 and strain Lb.l 204. The EOP (Efficiency of Plaquing) values for the four phages (Cb1/204, Cb1/342, Cb1/342modified and Cb1/342unmodified) suggested that an R/M system modified the original temperate phage, and the BglII-DNA restriction patterns of these phages might point out the presence of a Type II R/M system. Also, the existence of a Type I R/M system was demonstrated by PCR and nucleotide sequence, being the percentages of alignment homology with Type I R/M systems reported previously higher than 95%. In this study it was possible to demonstrate that the native phage resistant mechanisms and the occurrence of prophages in commercial host strains, contribute strongly to diversify the phage population in a factory environment.
authors.affiliation: Instituto de Lactología Industrial (UNL-CONICET), Facultad de Ingeniería Química, Santiago del Estero 2829, 3000 Santa Fe, Argentina.
authors.forename: Viviana
authors.initials: V
authors.lastname: Suárez
authors.forename: Miriam
authors.initials: M
authors.lastname: Zago
authors.forename: Giorgio
authors.initials: G
authors.lastname: Giraffa
authors.forename: Jorge
authors.initials: J
authors.lastname: Reinheimer
authors.forename: Andrea
authors.initials: A
authors.lastname: Quiberoni
mesh_terms: D001435:Bacteriophages / Q000502:physiology*; D001483:Base Sequence; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D048668:Lactobacillus delbrueckii / Q000821:virology*; D008969:Molecular Sequence Data
chemical_list: D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial