csp-like genes of Lactobacillus delbrueckii ssp. bulgaricus and their response to cold shock

Abstract

The two csp-like genes from the lactic acid bacterium Lactobacillus delbrueckii ssp. bulgaricus were characterized and designated cspA and cspB. The gene cspA has been identified using a polymerase chain reaction (PCR)-based approach with degenerated primers and further characterized using an inverse PCR strategy. cspA encodes a protein of 65 amino acid residues which displays between 81 and 77% identity with proteins CspL and CspP of Lactobacillus plantarum. cspB has been identified as a cspA ortholog using the partial sequence of the L. bulgaricus ATCC11842. cspB encodes a protein of 69 amino acids which has 42% identity with CspA. Northern blot analyses showed that cspA is transcribed as a single gene and that its transcription increased after a temperature downshift from 42 to 25°C. In contrast, cspB is part of an operon transcribed at constant level irrespective of the temperature. These results indicate that cspA encodes the only Csp-like protein of L. bulgaricus induced by a downshift of temperature.

cspA, Cold shock, Freezing, Lactobacillus delbrueckii ssp. bulgaricus