DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Item Strategies to select yeast starter cultures for production of flavour compounds in cachaça fermentations.(2012) Souza, Anderson Proust Gonçalves de; Vicente, Maristela de Araújo; Klein, Raphael Contelli; Fietto, Luciano Gomes; Coutrim, Maurício Xavier; Afonso, Robson José de Cássia Franco; Araújo, Leandro Dias; Alves, Paulo Henrique; Bouillet, Leoneide Érica Maduro; Castro, Ieso de Miranda; Brandão, Rogélio LopesIn this work, we have used classical genetics techniques to find improved starter strains to produce cachac¸a with superior sensorial quality. Our strategy included the selection of yeast strains resistant to 5,50,500-trifluor-D,L-leucine (TLF) and cerulenin, since these strains produce higher levels of higher alcohols and esters than parental strains. However, no clear relationship was observed when levels of flavoring compounds were compared with the levels expression of the genes (BAT1, BAT2, ATF2, EEB1 genes) involved with the biosynthesis of flavoring compounds. Furthermore, we determined the stability of phenotypes considered as the best indicators of the quality of the cachac¸a for a parental strain and its segregants. By applying the principal component analysis, a cluster of segregants, showing a high number of characteristics similar to the parental strain, was recognized. One segregant, that was resistant to TLF and cerulenin, also showed growth stability after six consecutive replications on plates containing high concentrations of sugar and ethanol. ‘‘Cachac¸a’’ produced at laboratory scale using a parental strain and this segregant showed a higher level of flavoring compounds. Both strains predominated in an open fermentative process through seven cycles, as was shown by mitochondrial restriction fragment length polymorphisms analysis. Based on the physical chemical composition of the obtained products, the results demonstrate the usefulness of the developed strategies for the selection of yeast strains to be used as starters in ‘‘cachac¸a’’ production.Item Isolation of Saccharomyces cerevisiae strains producing higher levels of flavoring compounds for production of ‘‘cachaça’’ the Brazilian sugarcane spirit.(2006) Vicente, Maristela de Araújo; Fietto, Luciano Gomes; Castro, Ieso de Miranda; Santos, Ana Nery Gonçalves dos; Coutrim, Maurício Xavier; Brandão, Rogélio LopesIn Brazil, spontaneous fermentation and open vessels are still used to produce cachac¸a (the Brazilian sugarcane spirit) and this fermentation is characterized by mixed cultures with continuous succession of yeast species. This work shows the development of a methodology for isolation of yeasts, particularly Saccharomyces cerevisiae, used in the production of cachac¸a. According to the proposed strategy, the strains were selected for their ability to adapt to stress conditions encountered during fermentation of the sugarcane juice such as high sucrose concentration; high temperatures and high alcohol concentration; for their capacity to flocculate; and for their higher fermentative ability. For strains with such characteristics, specific procedures were employed to select for 5,5,5-trifluoro-dl-leucine (TFL) and cerulenin-resistant strains, since these characteristics are related to a higher capacity of production of the flavoring compounds isoamyl alcohol and caproic acid, respectively. The effectiveness of such a selection strategy was documented. Taken together, the results obtained present the development of a new strategy to isolate yeast strains with appropriated characteristics to be used in the cachac¸a industry. Moreover, the results obtained offer an explanation for the great variability in terms of chemical composition found in products obtained even in a single distillery.Item Carbonyl cyanidem - chlorophenylhydrazone induced calcium signaling and activation of plasma membrane H1-ATPase in the yeast Saccharomyces cerevisiae.(2008) Pereira, Michele B. P.; Tisi, Renata; Fietto, Luciano Gomes; Cardoso, Anamaria de Souza; França, Mônica M.; Carvalho, Fernanda Machado de; Trópia, Maria José Magalhães; Martegani, Enzo; Castro, Ieso de Miranda; Brandão, Rogélio LopesThe plasma membrane H1-ATPase from Saccharomyces cerevisiae is an enzyme that plays a very important role in the yeast physiology. The addition of protonophores, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), also triggers a clear in vivo activation of this enzyme. Here, we demonstrate that CCCP-induced activation of the plasma membrane H1-ATPase shares some similarities with the sugar-induced activation of the enzyme. Phospholipase C and protein kinase C activities are essential for this activation process while Gpa2p, a G protein involved in the glucose-induced activation of the ATPase, is not required. CCCP also induces a phospholipase Cdependent increase in intracellular calcium. Moreover, we show that the availability of extracellular calcium is required for CCCP stimulation of H1-ATPase, suggesting a possible connection between calcium signaling and activation of ATPase.Item The involvement of calcium carriers and of the vacuole in the glucose-induced calcium signaling and activation of the plasma membrane H+-ATPase in Saccharomyces cerevisiae cells.(2012) Bouillet, Leoneide Érica Maduro; Cardoso, Anamaria de Souza; Perovano, Eduardo; Pereira, R. R.; Ribeiro, Erica Milena de Castro; Trópia, Maria José Magalhães; Fietto, Luciano Gomes; Tisi, Renata; Martegani, Enzo; Castro, Ieso de Miranda; Brandão, Rogélio LopesPrevious work from our laboratories demonstrated that the sugar-induced activation of plasma membrane H+-ATPase in Saccharomyces cerevisiae is dependent on calcium metabolism with the contribution of calcium influx from external medium. Our results demonstrate that a glucose-induced calcium (GIC) transporter, a new and still unidentified calcium carrier, sensitive to nifedipine and gadolinium and activated by glucose addition, seems to be partially involved in the glucose-induced activation of the plasma membrane H+-ATPase. On the other hand, the importance of calcium carriers that can release calcium from internal stores was analyzed in glucose-induced calcium signaling and activation of plasma membrane H+-ATPase, in experimental conditions presenting very low external calcium concentrations. Therefore the aim was also to investigate how the vacuole, through the participation of both Ca2+-ATPase Pmc1 and the TRP homologue calcium channel Yvc1 (respectively, encoded by the genes PMC1 and YVC1) contributes to control the intracellular calcium availability and the plasma membrane H+-ATPase activation in response to glucose. In strains presenting a single deletion in YVC1 gene or a double deletion in YVC1 and PMC1 genes, both glucose-induced calcium signaling and activation of the H+-ATPase are nearly abolished. These results suggest that Yvc1 calcium channel is an important component of this signal transduction pathway activated in response to glucose addition. We also found that by a still undefined mechanism Yvc1 activation seems to correlate with the changes in the intracellular level of IP3. Taken together, these data demonstrate that glucose addition to yeast cells exposed to low external calcium concentrations affects calcium uptake and the activity of the vacuolar calcium channel Yvc1, contributing to the occurrence of calcium signaling connected to plasma membrane H+-ATPase activation.