CONICET | Buscador de Institutos y Recursos Humanos

Lactobacillus sakei is a lactic acid bacterium mainly found in meat and meat products. In order to understandthe factors favoring its adaptation to meat matrix, growth parameters and survival of the strain L. sakei 23Kin the presence of sarcoplasmic or myofibrillar extracts were assessed. Cytosolic proteins putatively involvedin the response of this strain to meat proteins were determined using 2D electrophoresis and thesignificantly regulated proteins were identified by Maldi Tof-MS analyses. From the 31 differentiallyexpressed spots, 16 occurred in the presence of myofibrillar extract while 6 proteins were modulated by thesarcoplasmic extract. Two dipeptidases were overexpressed in the presence of sarcoplasmic proteins, incorrelation to the protein degradation patterns obtained by SDS-PAGE. In the presence of the myofibrillarextract, L. sakei 23K overexpressed proteins related to energy and pyrimidine metabolism as well as ala- andtyr-tRNA synthetases, involved in translation, while others corresponding to general stress response,pyrimidine, vitamin and cofactor biosynthesis were down-regulated. The supplementary nutrients furnishedby meat extracts modulated the overexpression of proteins related to translation, peptide/amino acidmetabolism and energy production while the stress proteins were under regulated. The results obtained heresuggest that meat proteins would not represent a stress environment per se for L. sakei 23K in contrast to theharsh conditions during meat processing. This study has extended the understanding of the molecularresponses and growth mechanisms of L. sakei 23K in the presence of meat proteins. The transference ofgenomic information into useful biological insight is an important step for the selection of well-adaptedstrains for the achievement of high-quality fermented products.