Characterization of prophages containing ?evolved? Dit/Tal modules in the genome of Lactobacillus casei BL23

JOAQUINA FINA MARTIN; CARMEN SANCHEZ RIVAS ; SERGIO I. NEMIROVSGRAHAM F. HATFULL; ROSARIO DURÁN; CHARLES BOWMAN; CHRISTIAN CAMBILLAU; MARÍA EUGENIA DIETERLE; SERGIO I. NEMIROVSKY; DANIEL RUSSELL; MARIANA PIURI

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

SPRINGER

Lugar: Berlin; Año: 2016

0175-7598

Abstract Lactic acid bacteria (LAB) have many applications infood and industrial fermentations. Prophage induction and gen-eration of new virulent phages is a risk for the dairy industry. Weidentified three complete prophages (PLE1, PLE2, and PLE3) inthe genome of the well-studied probiotic strain Lactobacilluscasei BL23. All of them have mosaic architectures with homol-ogous sequences to Streptococcus, Lactococcus, Lactobacillus,and Listeria phages or strains. Using a combination of quantita-tive real-time PCR, genomics, and proteomics, we showed thatPLE2 and PLE3 can be induced?but with different kinetics?in the presence of mitomycin C, although PLE1 remains as aprophage. A structural analysis of the distal tail (Dit) and tailassociated lysin (Tal) baseplate proteins of these prophages andother L. casei/paracasei phages and prophages provides evi-dence that carbohydrate-binding modules (CBM) located withinthese Bevolved^ proteins may replace receptor binding proteins(RBPs) present in other well-studied LAB phages. The detailedstudy of prophage induction in this prototype strain in combina-tion with characterization of the proteins involved in host recog-nition will facilitate the design of new strategies for avoidingphage propagation in the dairy industry.