Phage-resistance linked to cell heterogeneity in the commercial strain Lactobacillus delbrueckii subsp. lactis Ab1.
The aim of this work was to study the relationship between the cell morphological heterogeneity and the phage-resistance in the commercial strain Lactobacillus delbrueckii subsp. lactis Ab1. Two morphological variants (named C and T) were isolated from this strain. Phage-resistant derivatives were isolated from them and the percentage of occurrence of confirmed phage-resistant cells was 0.001% of the total cellular population. Within these phage-resistant cell derivatives there were T (3 out of 4 total isolates) and C (1 out of 4 total isolates) variants. The study of some technological properties (e.g. proteolytic and acidifying activities) demonstrated that most of phage-resistant derivatives were not as good as the parental strain. However, for one derivative (a T variant), the technological properties were better than those of the parental strain. On the other hand, it was possible to determinate that the system of phage-resistance in the T variants was interference in adsorption step, with adsorption rates <15%. For the C variant derivative it was possible to demonstrate the presence of a restriction/modification system and, moreover, to determinate that this system could be Type I R/M.
Suárez
Viviana B
VB
Instituto de Lactología Industrial (Universidad Nacional del Litoral - CONICET), Santiago del Estero 2829, S3000AOM Santa Fe, Argentina. vivisuar@fiq.unl.edu.ar
Maciel
Natalia
N
Guglielmotti
Daniela
D
Zago
Miriam
M
Giraffa
Giorgio
G
Reinheimer
Jorge
J
D000327:Adsorption; D001435:Bacteriophages; D004269:DNA, Bacterial / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005838:Genotype; D006801:Humans; D048668:Lactobacillus delbrueckii / Q000145:classification / Q000235:genetics*; D008826:Microbial Sensitivity Tests / Q000379:methods; D009154:Mutation; D010641:Phenotype; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods; D013045:Species Specificity
D004269:DNA, Bacterial