1,720,957 research outputs found
Evaluation of the ability of commercial wine yeasts to form biofilms (mats) and adhere to plastic: implications for the microbiota of the winery environment
No full textCommercially available active dried wine yeasts are regularly used by winemakers worldwide to achieve reliable fermentations and obtain quality wine. This practice has led to increased evidence of traces of commercial wine yeast in the vineyard, winery and uninoculated musts. The mechanism(s) that enables commercial wine yeast to persist in the winery environment and the influence to native microbial communities on this persistence is poorly understood. This study has investigated the ability of commercial wine yeasts to form biofilms and adhere to plastic. The results indicate that the biofilms formed by commercial yeasts consist of cells with a combination of different lifestyles (replicative and non-replicative) and growth modes including invasive growth, bud elongation, sporulation and a mat sectoring-like phenotype. Invasive growth was greatly enhanced on grape pulp regardless of strain, while adhesion on plastic varied between strains. The findings suggest a possible mechanism that allows commercial yeast to colonise and survive in the winery environment, which may have implications for the indigenous microbiota profile as well as the population profile in uninoculated fermentations if their dissemination is not controlled.Ee Lin Tek, Joanna F. Sundstrom, Jennifer M. Gardner, Stephen G. Oliver and Vladimir Jirane
Phenotypic investigation of biofilm formation and transcriptional analysis of invasive growth of commercial wine Saccharomyces cerevisiae
Full text linkThis study investigated the morphological properties, environmental effects on and gene expression of biofilms, more specifically referred to as mats, formed by laboratory and commercial wine strains of Saccharomyces cerevisiae. Two morphological assays were conducted: mat formation and plastic adhesion. Mat features varied between strains and included various architectures, cellular morphologies, and incidence of invasive growth. One commercial strain, L2056, formed mats where a sector produced a distinctive mat morphology, which was retained when subcultured. In considering the role of biofilms in winery conditions, mat formation assays were also performed with grape pulp and adhesion to the soft plastic of common winery hoses. All strains grew invasively on all agar media and appeared to conduct fermentation on the grape-pulp mat assay. Some strains also had the ability to adhere to winery hose plastic. When only limited nitrogen was available, both laboratory and commercial wine strains formed mats with a subpopulation of cells that switched to filamentous and invasive growth. Such invasive growth was influenced by nitrogen concentration, the presence of a neighbouring mat, and by the addition of yeast metabolites. Ethanol and hydrogen sulfide were found to enhance invasive growth of cells within mats exposed to low levels of nitrogen whereas tryptophol and 2-phenylethanol suppressed this enhancement. Sulfite was found to delay overall mat growth. In an effort to understand the cellular decision to switch morphology, changes in the transcriptome of invasively growing cells were studied. In this analysis, 272 genes were identified to be upregulated and 84 genes were downregulated in invasively growing cells. Of the ten largest differentially expressed genes, four were genes encoding hexose transporters (HXT3, HXT4, HXT6 and HXT7) which had an increase in transcript abundance up to 13-fold. One hypothetical gene (AWRI796_5153) with a 6-fold increase in transcript abundance, has translation sequence homologous to an amidase domain. Following differential expression and Gene Ontology analysis, five GO categories represented the 37 significantly enriched GO terms in the upregulated gene set of invasively growing cells, these being glucose import, carbohydrate metabolic process, fungal-type cell wall organisation, medium-chain fatty acid biosynthetic process and cellular water homeostasis. Since cellular water homeostasis has not previously been associated with invasive growth, and four out of five genes in this group were found to be significantly upregulated in the invasively growing cells, further analysis of deletion mutants of each of these confirmed that FPS1, encoding the glycerol export protein, is required for invasive growth of yeast mats in low nitrogen conditions. In summary, this work reports the phenotypic properties of commercial wine yeast biofilms in environments of both rich nutrient and low nitrogen, either in typical laboratory type agar media or in conditions simulating that of a grape or wine hose. The ability of these yeasts to form complex morphologies, grow invasively into grape solids and attach to winery hose plastic may confer their residency and survival in the vineyard and winery. The influence of different yeast metabolites and transcriptional changes in invasively growing cells provide further understanding of this morphogenetic program.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Agriculture, Food and Wine, 2017
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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