Identification of a Cold Shock Gene in Lactic Acid Bacteria and the Effect of Cold Shock on Cryotolerance

Abstract

When Lactic Acid Bacterial cultures were frozen at -20 degrees C for 24 h, the cell viability decreased drastically, but when they were cold shocked at 10 degrees C for 2 h prior to freezing, viability improved significantly for the Lactococcus lactis subsp. lactis strains (25-37%) and Pediococcus pentosaceus PO2 (18%), but not for the Lactococcus lactis subsp. cremoris strains tested or for one strain of Lactobacillus helveticus LB1 and Streptococcus thermophilus TS2. When the period for cold shock was extended to 5 h, the viability increased even further for those strains that displayed cold shock cryotolerance. Use of degenerate PCR primers based on the major cold shock protein (csp) of both Escherichia coli and Bacillus subtilis resulted in PCR products from all strains tested. The PCR product from Lactococcus lactis ssp. lactis M474 was cloned and sequenced, and the deduced amino acid sequence displayed a high sequence similarity to other csp's. Use of PCR primers based on the M474 sequence resulted in PCR products being produced only from the lactococcal strains studied and not from the Lactobacillus helveticus, Streptococcus thermophilus, or Pediococcus pentosaceus strains tested.

Cold Shock Proteins ofLactococcus lactisMG1363 Are Involved in Cryoprotection and in the Production of Cold-Induced Proteins

“…Since LAB starter cultures are frequently stored frozen, it is of practical relevance to monitor the abilities of these bacteria to survive freezing temperatures and to determine the critical factors for survival. L. lactis is able to adapt to freezing conditions by preexposure to 10°C, yielding increased survival in freezing conditions (20,35). For strain NZ9000, preexposure to 10°C for 2 and 4 h increased the survival of freezing approximately 50-and nearly 1,000-fold, respectively, after four repetitive freeze-thaw cycles (Fig.…”

Lactic Acid Bacteria Selection for Biopreservation as a Part of Hurdle Technology Approach Applied on Seafood

“…Indeed, LAB are generally naturally tolerant to freezing. Several studies demonstrated a correlation between CSP (CspL and CspP) produced after a cold-shock at suboptimal temperatures and cryotolerance (Kim and Dunn, 1997;Derzelle et al, 2003;Song et al, 2014).…”

Dynamic Stresses of Lactic Acid Bacteria Associated to Fermentation Processes

“…The roles of these proteins are at the levels of membrane fluidity, DNA supercoiling and transcription and translation. Few papers have described cold shock proteins and mechanisms in LAB, in particular they have focused on Lactococcus lactis and L. plantarum [39][40][41][42]. Kim et al [39,40] tested different LAB to evaluate cold shock effects on cryotolerance.…”

“…Few papers have described cold shock proteins and mechanisms in LAB, in particular they have focused on Lactococcus lactis and L. plantarum [39][40][41][42]. Kim et al [39,40] tested different LAB to evaluate cold shock effects on cryotolerance. Improved understanding of cold-shock-induced cryotolerance may contribute to the development of environmental conditions that allow improved viability/activity of frozen or freeze-dried commercial LAB starter cultures.…”