Trace amounts of the carcinogenic ethyl carbamate can appear in wine as a result of a reaction between ethanol and citrulline, which is produced from arginine degradation by some bacteria used in winemaking. In this study, arginine deiminase (ADI) pathway genes were evaluated in 44 Oenococcus oeni strains from wines originating from several locations in order to establish the relationship between the ability of a strain to degrade arginine and the presence of related genes. To detect the presence of arc genes of the ADI pathway in O. oeni, pairs of primers were designed to amplify arcA, arcB, arcC and arcD1 sequences. All strains contained these four genes. The same primers were used to confirm the organization of these genes in an arcABCD1 operon. Nevertheless, considerable variability in the ability to degrade arginine among these O. oeni strains was observed. Therefore, despite the presence of the arc genes in all strains, the expression patterns of individual genes must be strain dependent and influenced by the different wine conditions. Additionally, the presence of arc genes was also determined in the 57 sequenced strains of O. oeni available in GenBank, and the complete operon was found in 83% of strains derived from wine. The other strains were found to lack the arcB, arcC and arcD genes, but all contained sequences homologous to arcA, and some of them had also ADI activity.
The aim of this study was a reliable intra-species discrimination and strain biodiversity in Oenococcus oeni populations of two different Aglianico wineries by molecular, biochemical, and physiological characterization. Pulsed field gel electrophoresis (PFGE) analysis revealed a high polymorphism related to the origin (winery) of strains, while differential display PCR (DD-PCR) allowed a further discrimination of strains from the same winery. Moreover, the heterogeneity of these natural populations was investigated by capillary electrophoresis and enzymatic assays. A variability related to a different surface charge distribution was observed among strains, linked to their origin. Malolactic activity study evidenced strain-specific differences in malic acid degradation, and then, only the presence of L(-)-malic acid in the medium induced the mle gene. This study provided evidences on the importance of intra-species biodiversity of malolactic bacterial populations in wine ecosystems, as each wine possess peculiar winemaking conditions and physical-chemical properties which make specific the bacterial survival and growth. This study highlighted a great biodiversity among O. oeni strains that can be also winery specific. Such biodiversity within a certain winery and winemaking area is important for selecting malolactic starters, and strain-specific trait identification is especially important to match individual strains to specific industrial process.
Five Oenococcus oeni strains, selected from spontaneous malolactic fermentation (MLF) of Patagonic Pinot noir wine, were assessed for their use as MLF starter cultures. After the individual evaluation of tolerance to some stress conditions, usually found in wine (pH, ethanol, SO2, and lysozyme), the behavior of the strains was analyzed in MLO broth with 14 % ethanol and pH 3.5 in order to test for the synergistic effect of high ethanol level and low pH and, finally, in a wine-like medium. Although the five strains were able to grow in MLO broth under low pH and/or high ethanol, they must be acclimated to grow in a wine-like medium. Additionally, glycosidase and tannase activities were evaluated, showing differences among the strains. The potential of the strains to ferment citrate was tested and two of the five strains showed the ability to metabolize this substrate. We did not detect the presence of genes encoding histidine, tyrosine descarboxylase, and putrescine carbamoyltransferase. All the strains tested exhibited good growth capacity and ability to consume L-malic acid in a wine-like medium after cell acclimation, and each of them showed a particular enzyme profile, which might confer different organoleptic properties to the wine.
In this study, we compared different total protein extraction protocols to achieve highly efficient isolation and purification of total proteins for the specific protein profiling of Oenococcus oeni. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns obtained for the different extraction protocols revealed not only a qualitative similar protein pattern but also quantitative variations with different intensity bands depending on the extraction method used. The selected extraction method added with sonication proved to work extremely well and efficiently and was able to obtain a high-resolution 2-D electrophoresis (2-DE) map. Prominent spots were successfully identified by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry and corresponded to 76 different proteins involved in the main metabolic pathways. The approach allowed to achieve a protein profiling specific for O. oeni from Aglianico wine with numerous characterized protein products corresponding to many different O. oeni genes and associated with main cellular pathways. Further investigations of the 2-DE protein expression profile will provide useful and interesting information on the molecular mechanisms at the protein level responsible for growth and survival of O. oeni in wine.
- MeSH
- 2D gelová elektroforéza MeSH
- bakteriální proteiny analýza izolace a purifikace MeSH
- elektroforéza v polyakrylamidovém gelu MeSH
- molekulární biologie metody MeSH
- Oenococcus chemie izolace a purifikace MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- víno mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
