1,721,017 research outputs found
“Parasitic” design strategies for environmental and social sustainability. Vision of a diffuse universe of parasitic products and services”
No full textSaccharomyces bayanus var. uvarum and Saccharomyces cerevisiae succession during spontaneous fermentations of Amarone and Recioto wines
No full textThis study was undertaken to evaluate the biodiversity of the indigenous Saccharomyces
sensu stricto population during traditional vinification processes of Recioto and
Amarone wines using molecular typing techniques. In total 109 isolates, collected from eight
wineries during spontaneous fermentations, were identified and characterised by conventional
tests and by molecular methods, i.e. PCR fingerprinting using the primer (GTG)5,
mtDNA restriction and karyotype analyses. Sixty per cent of the isolates were assigned to
Saccharomyces bayanus var. uvarum and 40% to Saccharomyces cerevisiae. A succession
between S. bayanus var. uvarum, which dominated the first fermentation, and S. cerevisiae,
which appeared after the wine drawing-off operation, was observed during a traditional
Amarone winemaking. An extensive polymorphism was found between the isolates, however
a few specific genetic biotypes prevailed in the different wineries. This ecotaxonomic survey
constitutes a basic step to safeguard and exploit the oenological potential of the yeast
biodiversity in the Recioto and Amarone wine ecosystems. Such biodiversity could be further
explored to correlate the genetic patterns of the isolates with oenologically useful characteristics,
with the ultimate goal to carry out selection programmes of typical strains of the
Valpolicella area
Rapid identification of Saccharomyces cerevisiae, Saccharomyces bayanus and their hybrids by multiplex PCR
No full textAims: To develop a multiplex PCR assay for the specific identification and differentiation of Saccharomyces
cerevisiae, S. bayanus and their hybrids.
Methods and Results: Two sets of primers with sequences complementary to the region YBR033w were used. A
single amplicon of 1710 bp or 329 bp was obtained with species S. cerevisiae and S. bayanus, respectively, while the
presence of both bands was observed in S. pastorianus because of its hybrid nature. Both amplification products were
also obtained after amplification from DNA of several laboratory S. cerevisiae · S. bayanus hybrid strains.
Conclusions: Multiplex PCR was optimized for the rapid and reliable identification of S. cerevisiae, S. bayanus
and their hybrids.
Significance and Impact of the Study: The procedure may be used for routine detection of the most common
Saccharomyces sensu stricto yeasts involved in industrial fermentation processes, overcoming the problems of
conventional techniques
A study on yeasts from valpolicella wines (Italy): identification and characterization of Saccharomyces sensu strictu strains by genetic and physiological methods
No full textInfluenza delle caratteristiche enologiche sulla successione di Saccharomyces bayanus e S. cerevisiae nei vini Recioto e Amarone della Valpolicella.
No full textUn totale 25 di ceppi di S. bayanus e S. cerevisiae isolati da vini Amarone e Recioto in fermentazione spontanea sono stati studiati riguardo ai caratteri enologici e qualitativi. Le due specie sono state confrontate analizzando la loro capacità di resistere a differenti concentrazioni di SO2 ed etanolo, la produzione di H2S e per il fenotipo killer. Nel corso di microvinificazioni effettuate in laboratorio è stata valutata la capacità di crescere a basse temperature, per il potere alcoligeno assoluto e sono stati confrontati i valori di alcuni prodotti della fermentazione tra i vini ottenuti da Saccharomyces bayanus e S. cerevisiae. I ceppi di S. cerevisiae hanno mostrato maggiore resistenza all'SO2, all'etanolo e un più alto potere alcoligeno assoluto, mentre quelli di S. bayanus hanno evidenziato una migliore capacità di crescita a 6°C. E' stata osservata una prevalenza di fenotipi sensibili alla tossina killer K2 nella specie S. bayanus e una frequenza maggiore di medio e alto produttori di H2S in S. cerevisiae. Dalle analisi chimiche effettuate sui vini fermentati, la concentrazione degli zuccheri residui, dell'etanolo, del glicerolo e il valore di pH sono risultati significativamente differente. I differenti tratti enologici che caratterizzano S. bayanus e S. cerevisiae influenzano la loro evoluzione durante i processi spontanei di fermentazione dei vini Amarone e Recioto
Studio eco-enologico di lieviti Saccharomyces dei vini Recioto e Amarone della Valpolicella
No full textRapid identification of the sibling species Saccharomyces cerevisiae and Saccharomyces bayanus and of their hybrids by a multiplex PCR assay
No full textTechnological and genetic aspects of Lactobacillus delbrueckii subsp. indicus involved in the production of novel fermented milks.
No full textFour Lactobacillus strains isolated from an Indian fermented milk have recently been grouped in the new subspecies L. delbrueckii subsp. indicus (1). Previous studies have evidenced that these strains ferment lactose constitutively, like L. delbrueckii subsp. bulgaricus (1). However, lactose degradation is probably related to the presence of a peculiar genetic equipment since any amplification of the lac operon genes was achieved. No additional information is currently available on technological and genetic properties of these strains. In the present study, the ability of the four Indian strains to induce pleasant organoleptic traits when grown in milk-based media of different composition was investigated. Physical and chemical parameters were monitored during milk fermentation in order to establish the performances of the examined strains. In addition, sequences of genes encoding some lactose-PTS system components were obtained suggesting that lactose degradation in the Indian strains is probably due to the presence of these genetic determinants. Finally, a comparison of technological and genetic characteristics displayed by the different L. delbrueckii subspecies was conducted. The data obtained indicate that L. delbrueckii subsp. indicus strains show interesting properties and may be applied in association with S. thermophilus for the production of novel fermented milks
The role of genotype and phenotype in the infraspecific taxonomy of Lactobacillus species.
No full textData recently obtained for two infraspecific groups within the species Lactobacillus delbrueckii and Lactobacillus plantarum led to the description of two novel subspecies: Lactobacillus delbrueckii subsp. indicus (Dellaglio et al., 2005) and Lactobacillus plantarum subsp. argentoratensis (Bringel et al., in press), respectively.
Subspecies are the lowest taxonomic ranks with standing in nomenclature and are based on the recognition of phenotypic and/or genotypic heterogeneities (Rosselló-Mora & Amann, 2001). The descriptions of the aforementioned subspecies were the result of a polyphasic approach. It allowed to highlight that, in both species, the genotypic/genomic diversity was more marked than the phenotypic one. Moreover, in the case of L. delbrueckii, the phenotypic similarity between two subspecies was due to a phenomenon of convergent evolution: two different genetic equipments were responsible of the same phenotypic manifestation (Germond et al., 2003).
On the basis of those results, we present some considerations on the contribution that phenotypic and genotypic/genomic data may give to the delineation of subspecies. The experimental results presented make us suggest that prominent role in infraspecific taxonomy should be given to genotype since laboratory conditions could be misleading in the evaluation of “in vivo” expressed traits (phenotype) and, most of all, genotypic/genomic analysis is fundamental to understand which potentialities an organism could express
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