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A ten-year study (from 2008 to 2017) was conducted to analyse and critically discuss the chemical and sensorial characteristics showed by an innovative sweet red wine (named Predicatore), in order to individuate the influence of the main operating conditions on the quality of this product and to define its ageing potential. An innovative wine-making process was developed to valorise the grape wastes generated by the cluster thinning of Merlot grapes growing in La Cura winery (Tuscany, Italy). The production protocol is based on an annually variable blend between Aleatico and Merlot or Cabernet grapes, differently treated before winemaking in order to increase their sugar content. By the merging of the chemical and sensorial characterization of the wines analysed, it was possible to conclude that their colour appears mainly influenced by the meteorological conditions recorded during grape growing, while the ageing process deeply influences their volatile composition. [ABSTRACT FROM AUTHOR]

Syrah grapes harvested during the 2017 crop season in a biodynamic farm located in a hillside area around Lucca (Tuscany) were processed following a whole bunch winemaking, and the results were compared with those obtained by a traditional destemming winemaking in order to explore the potential quality of this kind of grape. With the aim to verify the impact of co-fermentation of intact grape clusters and stalk, both chemical and sensory profiles of wines were discussed soon after racking off as well as after 10 moths of ageing, and particular attention was paid to phenolic and aromatic compounds. Our results show that co-fermentation of intact grape clusters and stalk can be profitably applied in order to improve the nutraceutical features of Syrah wines as well as to emphasize their aromatic expression, thus allowing to significantly speed up their ageing phase. [ABSTRACT FROM AUTHOR]

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Strain variation in the acidophile Acidithiobacillus ferrooxidans was examined as a product of membrane adaptation in response to pH stress. We tested the effects of sub and supra-optimal pH in two type strains and four strains isolated from acid mine drainage water around Sudbury, Ontario, Canada. Growth rate, membrane fluidity and phase, determined from the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene, and fatty acid profiles were compared. The effect of pH 1.5 was the most pronounced compared to the other pH values of 1.8, 3.1, and 3.5. Three different types of response to lower pH were observed, the first of which appeared to maintain cellular homeostasis more effectively. This adaptive mode included a decrease in membrane fluidity and concomitant depression of the phase transition in two distinct membrane lipid components. This was explained through the increase in saturated fatty acids (predominantly 16:0 and cyclopropane 19:0 w8c) with a concomitant decrease in 18:1 w7c fatty acid. The other strains also showed common adaptive mechanisms of specific fatty acid remodeling increasing the abundance of short-chain fatty acids. However, we suspect membrane permeability was compromised due to potential phase separation, which may interfere with energy transduction and viability at pH 1.5. We demonstrate that membrane physiology permits differentiating pH tolerance in strains of this extreme acidophile. [ABSTRACT FROM AUTHOR]

Acid mine drainage (AMD) from mining activities can cause major environmental problems. The acidity is due in part to the microbial oxidation of sulfide minerals in the exposed ores. As little is known about seasonal variations of microbial population sizes in AMD, the objective of this investigation was to quantify the principal bacterial populations (iron-oxidizing acidophiles, sulfur-oxidizing acidophiles, sulfur-oxidizing neutrophiles, and acidophilic heterotrophs), with respect to season. The AMD sites sampled were four streams emerging from a copper/nickel tailings area. All bacterial populations with the exception of acidophilic sulfur oxidizers were recovered throughout the year. The most numerous bacteria were acidophilic heterotrophs and iron-oxidizing acidophiles. Surprisingly, there were no obvious trends in the relative abundance of the various bacterial groups as a function of season. Recovery of the various bacterial groups at an incubation temperature of 4 °C indicated that psychrotrophic members do exist. During the course of the investigation, it was observed that the number of Acidithiobacillus ferrooxidans (Thiobacillus ferrooxidans) colonies recovered on iron salts purified agarose, a preferred medium, was highly variable. The variability was attributed to the presence of non-iron-oxidizing satellite bacteria, the growth of which could be suppressed by increasing the concentration of the electron donor ferrous sulfate. [ABSTRACT FROM AUTHOR]

A variety of microorganisms can exist in acid mine drainage (AMD) environments, although their contribution to AMD problems is unclear. Environmental strains of Thiobacillus ferrooxidans and Thiobacillus acidophilus were purified by repeated plating and single-colony isolation on iron salts and tetrathionate media, respectively. Thiobacillus thiooxidans was enriched on sulfur-containing media. For the isolation of Leptospirillum ferrooxidans, iron salts and pyrite media were inoculated with environmental samples. However, L. ferrooxidans was never recovered on solid media. Denatured chromosomal DNAs from type and (or) isolated strains of T. ferrooxidans, T. acidophilus, T. thiooxidans, and L. ferrooxidans were spotted on a master filter for their detection in a variety of samples by reverse sample genome probing (RSGP). Analysis of enrichments of environmental samples by RSGP indicated that ferrous sulfate medium enriched T. ferrooxidans strains, whereas all thiobacilli grew in sulfur medium, T. thiooxidans strains being dominant. Enrichment in glucose medium followed by transfer to tetrathionate medium resulted in the selection of T. acidophilus strains. DNA was also extracted directly (without enrichment) from cells recovered from AMD water or sediments, and was analyzed by RSGP to describe the communities present. Strains showing homology with T. ferrooxidans and T. acidophilus were found to be major community components. Strains showing homology with T. thiooxidans were a minor community component, whereas strains showing homology with L. ferrooxidans were not detected.Key words: AMD, bacteria, DNA probing.Une foule de micro-organismes peuvent exister dans des environnements de drainages de mines acides (DMA), bien que leur rôle dans les problèmes des DMA est incertain. Des souches environnementales de Thiobacillus ferrooxidans et de Thiobacillus acidophilus ont été purifiées par étalement et isolement de colonies simples, à répétition, sur des milieux à base de sels de fer et de tétrathionate, respectivement. Thiobacillus thiooxidans fut enrichi dans un milieu contenant du soufre. Pour l'isolement de Leptospirillum ferrooxidans, des milieux à base de sels de fer et de pyrite ont été inoculés avec des échantillons environnementaux. Toutefois, L. ferrooxidans n'a jamais pu être isolé à partir de milieux solides. Des ADNs chromosomiques dénaturés de souches types et (ou) isolées de T. ferrooxidans, T. acidophilus, T. thiooxidans et L. ferrooxidans ont été déposés sur un filtre primaire pour leur détection dans une multitude d'échantillons à l'aide d'un sondage génomique inverse des échantillons (RSGP - « reverse sample genome probing »). L'analyse des enrichissements des échantillons environnementaux par RSGP a indiqué que le milieu à base de sulfate ferreux a enrichi les souches de T. ferrooxidans, alors que toutes les thiobacilles, dominées par les souches de T. thiooxidans, ont poussé dans un milieu à base de soufre. Un enrichissement dans un milieu à base de glucose suivi par un transfert dans un milieu à base de tétrathionate a permis la sélection de souches de T. acidophilus. De l'ADN fut également extrait directement (sans enrichissement) de cellules recueillies d'eaux ou de sédiments de DMA et fut analysé par RSGP afin de décrire les communautés présentes. Les souches présentant des homologies à T. ferrooxidans et T. acidophilus se sont révélées être les composantes majoritaires des communautés. Les souches présentant des homologies à T. thiooxidans constituaient une composante minoritaire des communautés, alors que les souches présentant des homologies à L. ferrooxidans n'ont pas été détectées.Mots clés : DMA, bactéries, sondage d'ADN.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The purpose of this investigation was to determine the effect of Thiobacillus acidophilus on the leaching of a low-grade Cu-Ni sulfide ore by Thiobacillus ferrooxidans. A sample of low-grade Cu-Ni sulfide ore containing 0.36% Cu, 0.48% Ni, and 7.87% Fe was pulverized and initially leached for a 21-day period using two different pure cultures of T. ferrooxidans, an environmental strain (F2) and a strain from the American Type Culture Collection (ATCC 23270). Samples of the ore slurries were drawn and the pH was monitored over the course of the leaching period. The concentrations of Cu and Ni leached by each strain were determined and compared. No significant differences were observed in the concentrations of Cu and Ni leached by the two pure cultures of T. ferrooxidans. Subsequently, the ore was leached with mixed cultures of T. ferrooxidans and T. acidophilus to determine the effect of the latter on the concentrations of Cu and Ni leached from the ore. The environmental strain F2 of T. ferrooxidans was used in combination with both a type strain (ATCC 27807) and an environmental strain (64) of T. acidophilus. After 21 days, the mixed cultures of T. ferrooxidans and T. acidophilus leached significantly greater amounts of copper than the pure strain alone, but no such difference was observed for the leaching of nickel. [ABSTRACT FROM AUTHOR]

Cell-free extracts of the yeast Saccharomyces cerevisiae can be used to catalyse the recombination of bacterial plasmids in vitro. Recombination between homologous plasmids containing different mutations in the gene encoding tetracycline resistance is detectable by the appearance of tetracycline-resistance following transformation of the recombinant plasmid DNA into Escherichia coli DH5. This in vitro recombination system was used to determine the involvement of eukaryotic topo-isomerases in genetic recombination. Cell-free extracts prepared from a temperature-sensitive topo-isomerase II mutant ( top2-1) of S. cerevisiae yielded tetracycline-resistant recombinants, when the recombination assays were performed at both a non-restrictive temperature (30°C) and the restrictive temperature (37°C). This result was obtained whether or not ATP was present in the recombination buffer. Extracts from a non-conditional topo-isomerase I mutant ( top1-1) of S. cerevisiae yielded tetracycline-resistant recombinants, as did a temperature-sensitive double mutant ( top2-1/top1-8) at the restrictive temperature. The results of this study indicate that neither topo-isomerase I nor topo-isomerase II was involved in the recombinational activity examined. [ABSTRACT FROM AUTHOR]

Different strains of Thiobacillus ferrooxidans were examined for their ability to produce a heat shock and a cold shock response. Strain A1, heat shocked from 20° to 35°C, acquired thermotolerance, as it showed a 1000-fold reduction in cell mortality when exposed to the supermaximum temperature of 42°C, as compared to a non-heat-shocked control. A heat shock from 25° to 35°C yielded similar results, although a higher degree of thermotolerance was achieved for the shorter exposure times. Cultures heat shocked for 5 h showed a five-log reduction in viable counts after 41 h at 42°C, whereas non-heat-shocked cultures showed a similar reduction in viability in 28 h. Conferred thermotolerance was immediate and sustained for the duration of the exposure to 42°C. Heat-shocked cultures were not significantly protected against loss of viability due to freezing (-15°C for 24 h). Strain S2, cold shocked from 25° to 10°C, and strain D6, cold shocked from 25° to 5°C, were not protected against freezing at-15°C. An analysis of proteins extracted from heat-shocked cells of strain A1 showed the presence of at least one newly induced protein and eight hyper-induced proteins. The molecular weights of the heat shock proteins were in the range of 15-80.3 kDa. [ABSTRACT FROM AUTHOR]

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper. [ABSTRACT FROM AUTHOR]