Search Results (3)

The wine aromatic profile is influenced by complex interactions between grapevine genotype and enological practices. Thus, the aim of this study was to investigate the combined effects of grapevine clones and yeast strains on the volatile composition and sensory properties of wines produced from the Croatian indigenous variety Moslavac. Wines from five registered Moslavac clones (PUS-017, PUS-026, PUS-030A, PUS-087, and PUS-111) were produced using two commercially available yeast strains (Lalvin QA23 and Zymaflore Xarom). Significant effects of both clone and yeast strain were observed, particularly for yeast-derived compounds, such as isoamyl alcohol, phenylethyl alcohol, and medium-chain fatty acids. Ester production was generally enhanced by the Xarom yeast strain, although clone differences were also observed. Grape-derived volatile compounds differed significantly among clones, with wines from clones PUS-030A and PUS-087 having higher concentrations of norisoprenoids and terpenes, while PUS-017 wines consistently displayed lower concentrations of volatile compounds. Furthermore, PCA and MLF analyses revealed a clear differentiation between clones, with the yeast strain having a secondary modulatory effect. The sensory results were consistent with chemical data, demonstrating that clonal selection plays a key role in defining aromatic expression and typicity of Moslavac wines. Full article

Mitochondrial respiratory chain supercomplexes (RCS), particularly, the respirasome, which contains complexes I, III, and IV, have been suggested to participate in facilitating electron transport, reducing the production of reactive oxygen species (ROS), and maintaining the structural integrity of individual electron transport chain (ETC) complexes. Disassembly of the RCS has been observed in Barth syndrome, neurodegenerative and cardiovascular diseases, diabetes mellitus, and aging. However, the physiological role of RCS in high energy-demanding tissues such as the heart remains unknown. This study elucidates the relationship between RCS assembly and cardiac function. Adult male Sprague Dawley rats underwent Langendorff retrograde perfusion in the presence and absence of ethanol, isopropanol, or rotenone (an ETC complex I inhibitor). We found that ethanol had no effects on cardiac function, whereas rotenone reduced heart contractility, which was not recovered when rotenone was excluded from the perfusion medium. Blue native polyacrylamide gel electrophoresis revealed significant reductions of respirasome levels in ethanol- or rotenone-treated groups compared to the control group. In addition, rotenone significantly increased while ethanol had no effect on mitochondrial ROS production. In isolated intact mitochondria in vitro, ethanol did not affect respirasome assembly; however, acetaldehyde, a byproduct of ethanol metabolism, induced dissociation of respirasome. Isopropanol, a secondary alcohol which was used as an alternative compound, had effects similar to ethanol on heart function, respirasome levels, and ROS production. In conclusion, ethanol and isopropanol reduced respirasome levels without any noticeable effect on cardiac parameters, and cardiac function is not susceptible to moderate reductions of RCS. Full article

Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisiae. A preference for secondary compared to primary alcohols in oxidation direction was observed for YlADH2. 2-Octanone was investigated in reduction mode in detail. Remarkably, YlADH2 displays perfect (S)-selectivity and together with a highly (R)-selective short chain dehydrogenase/ reductase from Yarrowia lipolytica it is possible to access both enantiomers of 2-octanol in >99% ee with Yarrowia lipolytica oxidoreductases. Full article