Proteomic changes of Lactobacillus sakei CRL1756 upon expossure to NaCl stress

BELFIORE CAROLINA; FADDA SILVINA; MOZZI FERNANDA; VIGNOLO GRACIELA

Egmond aan Zee

Simposio; 10th Symposium on Lactic Acid Bacteria; 2011

FEMS

Although some lactic acid bacteria (LAB) species have become a major source of concern in aquaculture due to its pathological significance, LAB are able to grow on fish subjected to different technological processes. Previously, Leuconostoc and Lactobacillus were identified and characterized as the main genera present in fresh anchovies. Based on technological and safety traits and considering that salt can be a barrier to be overcome by LAB in salted fish products Lactobacillus sakei CRL1756 was selected for its highly NaCl tolerance. Different osmoprotectant compounds and a proteomic approach using two-dimensional polyacrylamide gel electrophoresis (2D PAGE) were applied to investigate the adaptive response of L. sakei CRL1756 to environmental osmotic stress. Among the assayed compatible solutes, glycine-betaine showed a high stimulatory effect on L. sakei CRL1756 growth in the presence of 10% NaCl. From the 50 significantly regulated proteins identified by MALDI TOF-MS analysis, 18 spots were differentially expressed in the presence of 10% NaCl, these involving 11 induced proteins while the expression of 7 spots were decreased/repressed in presence of salt. Among the 11 induced proteins by L. sakei CRL1756, 4 over-expressed spots were related to stress response and involved in the adaptation to atypical conditions and detoxification mechanisms (ClpL ATPasa, GrpE, DnaK, Dyp) and to carbohydrate metabolism while 4 proteins from glycolytic pathway exhibited a decreased expression, this suggesting a maintenance metabolism of L. sakei CRL1756 under NaCl stress. The transference of genomic information into biological insight constitutes an important tool for the selection of well-adapted strains.