Article

Identification of clinically important ascomycetous yeasts based on nucleotide divergence in the 5' End of the Large-Subunit (26S) Ribosomal DNA Gene

National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, Illinois 61604, USA.
Journal of Clinical Microbiology (Impact Factor: 3.99). 06/1997; 35(5):1216-23.
Source: PubMed

ABSTRACT

Clinically important species of Candida and related organisms were compared for extent of nucleotide divergence in the 5' end of the large-subunit (26S) ribosomal DNA (rDNA) gene. This rDNA region is sufficiently variable to allow reliable separation of all known clinically significant yeast species. Of the 204 described species examined, 21 appeared to be synonyms of previously described organisms. Phylogenetic relationships among the species are presented.

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    • "Total genomic DNA was extracted using the isopropanol method ( Querol et al . , 1992 ) , and the DNA for sequencing was amplified by using an Eppendorf Mastercycler , with forward NL - 1 primer ( 5 ′ - GCA TAT CAA TAA GCG GAG GAA AAG - 3 ′ ) and reverse NL - 4 primer ( 5 ′ - GGT CCG TGT TTC AAG ACG G - 3 ′ ) ( Kurtzman and Robnett , 1997 ) . The sequences obtained to identify yeasts were analyzed and compared by BLAST - search ( http : / / blast . "
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    ABSTRACT: Non-Saccharomyces yeasts are a heterogeneous microbial group involved in the early stages of wine fermentation. The high enzymatic potential of these yeasts makes them a useful tool for increasing the final organoleptic characteristics of wines in spite of their low fermentative power. Their physiology and contribution to wine quality are still poorly understood, with most current knowledge being acquired empirically and in most cases based in single species and strains. This work analyzed the metabolic potential of 770 yeast isolates from different enological origins and representing 15 different species, by studying their production of enzymes of enological interest and linking phylogenetic and enzymatic data. The isolates were screened for glycosidase enzymes related to terpene aroma release, the β-lyase activity responsible for the release of volatile thiols, and sulfite reductase. Apart from these aroma-related activities, protease, polygalacturonase and cellulase activities were also studied in the entire yeast collection, being related to the improvement of different technological and sensorial features of wines. In this context, and in terms of abundance, two different groups were established, with α-L-arabinofuranosidase, polygalacturonase and cellulase being the less abundant activities. By contrast, β-glucosidase and protease activities were widespread in the yeast collection studied. A classical phylogenetic study involving the partial sequencing of 26S rDNA was conducted in conjunction with the enzymatic profiles of the 770 yeast isolates for further typing, complementing the phylogenetic relationships established by using 26S rDNA. This has rendered it possible to foresee the contribution different yeast species make to wine quality and their potential applicability as pure inocula, establishing species-specific behavior. These consistent results allowed us to design future targeted studies on the impact different non-Saccharomyces yeast species have on wine quality, understanding intra and interspecific enzymatic odds and, therefore, aiming to predict the most suitable application for the current non-Saccharomyces strains, as well as the potential future applications of new strains. This work therefore contributes to a better understanding of the concept of wine microbiome and its potential consequences for wine quality, as well as to the knowledge of non-Saccharomyces yeasts for their use in the wine industry.
    Full-text · Article · Jan 2016 · Frontiers in Microbiology
    • "Then, representatives of each group and isolates with unique rep- PCR profiles were identified by 16S and 26S rRNA gene sequencing for bacteria and yeasts, respectively. RNA genes were amplified with the P1V1-P4V3 and NL1-NL4 primers for bacteria and yeasts, respectively (Klijn et al., 1991; Kurtzman and Robnett, 1997). The PCR products were purified by means of a PCR Extract Mini Kit (5PRIME, Milan, Italy) and sent to a commercial sequencing facility (MWG Biotech, Ebersberg, Germany). "
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    ABSTRACT: Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations inWest Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified bymeans of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii,while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, themost abundant species weremolecularly character- ized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progres- sion during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Tempera- tures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant infiuence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica specieswere shown to possess several enzymes that may impact the quality of the final product.
    No preview · Article · Oct 2015 · International journal of food microbiology
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    • "C. Primers NL-1 (5 0 -GCATAT CAA- TAAGCG GAG GAA AAG-3 0 ) and NL-4 (5 0 -GGT CCG TGT TTC AAG ACG G-3 0 ) (Elisabeth Pharmacon) were used for amplification. [28] "
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    ABSTRACT: Performance of a two-stage biofiltration system was investigated for removal of styrene-acetone mixtures. High steady-state acetone loadings (above Cin(Ac) = 0.5 g.m(-3) corresponding to the loadings > 34.5 g.m(-3).h(-1)) resulted in a significant inhibition of the system's performance in both acetone and styrene removal. This inhibition was shown to result from the acetone accumulation within the upstream trickle-bed bioreactor (TBR) circulating mineral medium, which was observed by direct chromatographic measurements. Placing a biofilter (BF) downstream to this TBR overcomes the inhibition as long as the biofilter has a sufficient bed height. A different kind of inhibition of styrene biodegradation was observed within the biofilter at very high acetone loadings (above Cin(Ac) = 1.1 g.m(-3) or 76 g.m(-3).h(-1) loading). In addition to steady-state measurements, dynamic tests confirmed that the reactor overloading can be readily overcome, once the accumulated acetone in the TBR fluids is degraded. No sizable metabolite accumulation in the medium was observed for either TBR or BF. Analyses of the biodegradation activities of microbial isolates from the biofilm corroborated the trends observed for the two-stage biofiltration system, particularly the occurrence of an inhibition threshold by excess acetone.
    Full-text · Article · Sep 2015 · Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering
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