INVESTIGADORES
FADDA Silvina Graciela
congresos y reuniones científicas
Título:
Effect of an inhibitory peptidic fraction produced by wine yeasts on the proteome of Oenococcus oeni.
Autor/es:
MENDOZA, L; FERNÁNDEZ DE ULLIVARRI M M; FADDA S; RAYA, R
Reunión:
Simposio; IV Simposio Internacional de Bacterias Lácticas-SIBAL CERELA- CONICET.; 2013
Institución organizadora:
cerela conicet
Resumen:
Oenococcus
oeni is the best adapted wine lactic acid bacterium and is almost exclusively
used for the induction of malolactic fermentation (MLF) which consists in the
convertion of malic acid into lactic acid at the end of the alcoholic
fermentation (AF) during wine-making process. MLF is a critical step to obtain
a high quality final product. However, bacterial growth and MLF are not always
successful due to the harsh environmental conditions of wine. In fact, some
inhibitory metabolites produced by yeasts during AF such as ethanol, SO2 and
peptides influence on O. oeni behavior. In a previous study we found that O.
oeni X2L reached less biomass in fermented medium as well as in presence of a
peptidic fraction produced by yeast (PF) than when it grew in the unfermented
medium (control), even though the MLF was completely achieved in all tested
conditions. To evaluate the possible mechanisms that O. oeni X2L utilizes to
survive and carry out the MLF in presence of PF, a proteomic approach was
performed using 2D electrophoresis. O. oeni X2L was grown in grape juice medium
with and without addition of PF. A total of 357 cytoplasmic proteins were
detected independently of growth conditions. Eleven protein spots showed
differential expression with a factor greater than 1.5 during bacterial growth
in presence of PF. Chaperone GroEL and elongation factor Tu were the only
proteins that decreased the expression when O. oeni was exposed to PF. Among
proteins up-regulated, two peptidases (oligopeptidase F and endopeptidase O),
acetolactate kinase and trascription terminator NusA showed the highest
expression change. Other proteins overexpressed with variable intensities were
ATP-binding subunit of Clp protease, DnaK/DnaJ chaperones and proteins related
to nucleotide and carbohydrate metabolism such as ribonuclease III,
dihydroxyacetone kinase, preprotein translocase and ribonucleotide diphosphate
reductase. The over-expression of general stress proteins and enzymes involved
in carbohydrate metabolism and nucleotide synthesis permits the growth and
enzymatic activity of O. oeni in presence of inhibitory PF. The results
obtained in this work contribute to the understanding of the molecular
mechanisms used by O. oeni to tolerate wine conditions, particularly its
response to the presence of inhibitory peptides produced by Saccharomyces
cerevisiae during AF. The knowledge of O. oeni response to stress will allow
the future selection of the best adapted strain as starter culture to carry out
successfully the MLF during wine-making.