196,067 research outputs found
Genetic segregation of natural Saccharomyces cerevisiae strains derived from spontaneous fermentation of Aglianico wine.
No full textBiological diversity of Saccharomyces yeasts of spontaneously fermenting wines in four wine regions: Comparative genotypic and phenotypic analysis
No full textCombination of molecular genetic analysis (karyotyping, PCR-RFLP of MET2, the ITS1-ITS2 region and the NTS
region) and physiological examination (melibiose and mannitol utilization, sugar-, ethanol- and copper
tolerance, killer activity, fermentation vigor and production of metabolites) of yeasts isolated from
spontaneously fermenting wines in four wine regions revealed very high diversity in the Saccharomyces
cerevisiae populations. Practically each S. cerevisiae isolate showed a unique pattern of properties. Although
the strains originating from the same wine were quite similar in certain traits, they showed diversity in other
properties. These results indicate that alcoholic fermentation in grape wines is performed by highly diverse
yeast consortia rather than by one or two dominating strains. The less frequent Saccharomyces uvarum
strains were less diverse, showed lower karyotype variability, were Mel+, Man+, more sensitive to 60%
sugar, and ethanol or copper in the medium. They produced less acetic acid and fermented better at 14 °C
than most of the S. cerevisiae isolates, but certain S. cerevisiae strains showed comparably high fermentation
rates at this temperature, indicating that it is not a general rule that S. uvarum ferments better than S.
cerevisiae at low temperatures. The segregation of certain traits (melibiose utilization, mannitol utilization
and copper resistance) in both species indicates that the genomes can easily change during vegetative
propagation. The higher diversity among the S. cerevisiae isolates suggests that the S. cerevisiae genome may
be more flexible than the S. uvarum genome and may allow more efficient adaptation to the continuously
changing environment in the fermenting wine
Polymorphism detection among wild Saccharomyces cerevisiae strains of different wine origin
No full textIn this study, wild Saccharomyces cerevisiae strains, isolated from spontaneously fermenting grapes of different varieties and origins, were submitted to genetic analysis using different molecular techniques, such as amplification of genes coding for cell wall proteins and containing minisatellite-like sequences, karyotyping, mtDNA-RFLP, and analysis of the δ region. The lowest discriminative power was obtained by minisatellites analysis, in particular the amplification of AGA1 genes. Karyotyping and mtDNA-RFLP analysis yielded the same differentiation among the strains, whereas the PCR amplification of δ sequences resulted the best method as it was fast and it showed a very high discriminative power. In any case, it has to be underlined that some strains, showing the same delta profiles, exhibited a different mtDNA restriction profile and electrophoretic karyotype, suggesting that more than one molecular marker is required for reliable strain discrimination. Although the techniques used revealed a different resolution power, they all revealed a genetic relationship among strains isolated from spontaneous fermentation of grapes of different origins. In fact, none of the typing methods was able to discriminate some strains isolated from different areas
Candida zemplinina sp. nov., an osmotolerant and psychrotolerant yeast that ferments sweet botrytized wines
No full textPhr1p, a glycosylphosphatidylinsitol-anchored β(1,3)-glucanosyltransferase critical for hyphal wall formation, localizes to the apical growth sites and septa in Candida albicans
No full textCell wall biogenesis is a dynamic process relying on the coordinated activity of several extracellular enzymes. PHR1 is a pH-regulated gene of Candida albicans encoding a glycosylphosphatidylinositol-anchored β(1,3)-glucanosyltransferase of family GH72 which acts as a cell wall remodelling enzyme and is crucial for morphogenesis and virulence. In order to explore the function of Phr1p, we obtained a green fluorescent protein (GFP) fusion to determine its localization. During induction of vegetative growth, Phr1p-GFP was concentrated in the plasma membrane of the growing bud, in the mother-bud neck, and in the septum. Phr1p-GFP was recovered in the detergent-resistant membranes indicating its association with the lipid rafts as the wild type Phr1p. Upon induction of hyphal growth, Phr1p-GFP highly concentrated at the apex of the germ tubes and progressively distributed along the lateral sides of the hyphae. Phr1p-GFP also labelled the hyphal septa, where it colocalized with chitin. Localization to the hyphal septa was perturbed in nocodazole-treated cells, whereas inhibition of actin polymerization hindered the apical localization. Electron Microscopy analysis of the hyphal wall ultrastructure of a PHR1 null mutant showed loss of compactness and irregular organization of the surface layer. These observations indicate that Phr1p plays a crucial role in hyphal wall formation, a highly regulated process on which morphogenesis and virulence rely
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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