177,062 research outputs found
Dual Role of Yeasts and Filamentous Fungi in Fermented Sausages
No full textThis contribution aims to review the presence and the potential double role-positive or beneficial and negative or harmful-of fungi in fermented sausages as well as their use as starter cultures. Traditionally, studies have been focused on lactic acid bacteria; however, over the years, interest in the study of fungi has increased. The important contribution of yeasts and filamentous fungi to the quality and safety of fermented sausages has emerged from reviewing the literature regarding these fermented products. In conclusion, this review contributes to the existing literature by considering the double role of filamentous fungi and yeasts, the global fermented sausage market size, the role and use of starters, and the starters mainly present in the worldwide market, as well as the main factors to take into account to optimize production. Finally, some suggestions for future broadening of the sector are discussed
Genetic Improvement of wine yeasts for opposite adsorption activity of phenolics and ochratoxin A during red winemaking
No full textThe aim of this research was to acquire new strains of Saccharomyces cerevisiae exhibiting opposite characteristics of cell wall adsorption: very high adsorption activity toward the ochratoxin A, very low adsorption activity toward the pigmented phenolic compounds contained in musts from black grapes. For this purpose, starting from 313 strains of Saccharomyces cerevisiae, 12 strains were pre-selected and used to obtain 27 intraspecific hybrids. Eleven crosses out of 27 were validated as hybrids; the best five hybrids were used in guided winemaking at four Calabrian wineries. The employed experimental protocol has allowed to select yeast strains for their different adsorption activity, improving the strains by spore clone selection and construction of intraspecific hybrids. These results suggest an efficacious way to improve the characteristics of interest in wine yeasts
Coumarin inhibits the growth of carrot (Daucus carota L. cv. Saint Valery) cells in suspension culture
No full textWe used a carrot (Daucus carota L. cv. Saint Valery) cell suspension culture as a simplified model system to study the effects of the allelochemical compound coumarin (1,2 benzopyrone) on cell growth and utilisation of exogenous nitrate, ammonium and carbohydrates. Exposure to micromolar levels of coumarin caused severe inhibition of cell growth starting from the second day of culture onwards. At the same time, the presence of 50μmol/L coumarin caused accumulation of free amino acids and of ammonium in the cultured cells, and stimulated their glutamine synthetase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase and phosphoenolpyruvate carboxylase activities. Malate dehydrogenase, on the other hand, was inhibited under the same conditions. These effects were interpreted in terms of the stimulation of protein catabolism and/or interference with protein biosynthesis induced by coumarin. This could have led to a series of compensatory changes in the activities of enzymes linking nitrogen and carbon metabolism. Because coumarin seemed to abolish the exponential phase and to accelerate the onset of the stationary phase of cell growth, we hypothesise that such allelochemical compounds may act in nature as an inhibitor of the cell cycle and/or as a senescence-promoting substance
Wine colour adsorption phenotype: An inheritable quantitative trait loci of yeasts
No full textAbstractAims: In this work, a population of 88 descendants derived from three wine strains of Saccharomyces cerevisiae was tested for the enological trait 'wine colour adsorption' (WCA) to evaluate its inheritability.Methods and Results: The WCA phenotype was tested on plate agar medium specifically formulated for the purpose. After 10 days of anaerobic incubation at 28°C, a computer-assisted assessment of WCA aptitude of the yeasts was carried out. The biomass colour – ranging from white to dark brown – reflects the adsorption of grape pigments: white and dark brown biomass colour corresponds to low and high adsorption, respectively. In order to confirm biomass colour results, microvinification trials using red must were performed, and the obtained wines were analysed.Conclusions: The analysis of the progeny demonstrated that the enological trait WCA is inheritable and polygenic.Significance and Impact of the Study: A way to describe the polygenic effect of the WCA trait has been found, also showing that this trait is inheritable. The impact of the work revolves more around the large-scale screening method, which could then assist in breeding wine yeast, and can also be used as a scientific tool to investigate WCA trait
Ochratoxin A adsorption phenotype: an inheritable yeast trait
No full textThis study aimed to evaluate the inheritance of the trait ochratoxin A adsorption in two wine
strains of Saccharomyces cerevisiae and their 46 descendants. Each strain was inoculated in
triplicate in test tubes containing 10 ml of must obtained from the Calabrian Zibibbo white grape
variety, artifi cially contaminated with ochratoxin A to reach a total content of 4.10 ng/ml. The
microvinifi cation trials were performed at 25°C. After 30 days, ochratoxin A values ranged from
0.74 to 3.18 ng/ml, from 0.01 to 2.69 ng/ml, and from 0.60 to 2.95 ng/ml respectively in wines, in
lees after washing, and in the saline solution used to wash the lees. The analysis of OTA in wines
was performed to fi nd the residual toxin content after yeast activity, thus obtaining technological
evidence of yeast infl uence on wine detoxifi cation. The analysis of OTA in lees after washing was
performed to distinguish the OTA linked to cells. The analysis of OTA in the saline solution used
to wash the lees was performed to distinguish the OTA adsorbed on yeast cell walls and removed
by washing, thus focusing on the adsorption activity of wine yeast through electrostatic
and ionic interactions between parietal mannoproteins and OTA. Ploidy of the two parental
strains was controlled by fl ow cytometry. Results demonstrated that the ochratoxin A adsorption
is genetically controlled and is a polygenic inheritable trait of wine yeasts. The majority of the
descendants are characterized by a great and signifi cant diversity compared to their parents.
Both the parental strains had genome sizes consistent with their being diploid, so validating the
observed results. These fi ndings constitute an initial step to demonstrate the mechanisms of
inheritance and establish breeding strategies to improve the ochratoxin A adsorption trait in wine
yeasts. This will allow a decrease in the ochratoxin A content of contaminated musts during
winemaking, by using genetically improved wine yeasts
Wine strain improvement strategies to enhance red wine safety based on parietal adsorption activity. 2. Yeast selection from Campania and Calabria.
No full textScreening for yeasts able to hydrolyse arbutin in the presence of glucose or ethanol
No full textThe study was carried out using 212 glucose-fermenting yeasts isolated from Calabrian and Sicilian samples of must and wine. They were screened for beta-glucosidase activity in Petri plates containing arbutin agar medium. Eleven strains (three apiculate yeasts and eight elliptic yeasts) were able to perform arbutin hydrolysis, but only strain C5, identified as Pichia anomala, maintained the ability to hydrolyse arbutin even in the presence of remarkable amounts of glucose or ethanol. This strain did not show the capacity to excrete the beta-glucosidase into the medium; effectively, the enzymatic activity in the culture supernatant was near to zero. However, its intracellular activity was high
Emerging Trends in Allelopathy: A Genetic Perspective for Sustainable Agriculture
No full textOver the past decades, a growing interest in allelopathy has been recorded due to the effective use of allelochemicals as growth regulators, bioherbicides, insecticides, and antimicrobial crop protection in the sustainable agriculture field. So far, the genetic aspects of the allelopathic effects have been poorly studied, and the identification of allelopathic genes and/or genomic regions (QTLs) has become a challenge to implement specific breeding programs. Here, we review the recent genetic and genome-based research findings in allelopathy, with a particular emphasis on weed control, which is one of the major crop yield-limiting factors. We discuss the key plant–microorganism interactions, including the cross-kingdom RNAi phenomenon and the involvement of microRNAs in allelopathy. Through this review, we wanted to lay the foundation for advancing knowledge in allelopathy and uncover the areas where research is needed
PHYTOPLANKTON DETECTION AND DSP TOXICITY - METHODOLOGICAL CONSIDERATIONS
No full textTwo different phytoplankton sampling methods (bottle and net sampling) were used to evaluate the concentration of toxic Dinophysis species in seawater and their correlation to mussel toxicity, assessed by mouse bioassay. Dinophysis concentration in net samples revealed the higher correlation to mussel toxicity (r = 0.75, p < 0.01). Net sampling therefore seems more suitable for the detection of low abundance species like Dinophysis characterised by vertical aggregations at different depths in the water column
Cultivable microbial ecology and aromatic profile of “mothers” for Vino cotto wine production
No full textThe aim of the present study was to assess the cultivable microbiota of “mothers” of Vino cotto collected from production of different years 1890, 1895, 1920, 1975, 2008. A total of 73 yeasts and 81 bacteria were isolated. Starmerella lactis-condensi, Starmerella bacillaris, Hanseniaspora uvarum, Saccharomyces cerevisiae, Hanseniaspora guillermondi and Metschnikowia pulcherrima were identified. Bacteria isolates belonged to lactic acid bacteria (Lactiplantibacillus plantarum and Pediococcus pentosaceus) and acetic acid bacteria (Gluconobacter oxydans). Remarkable biodiversity was observed for Starm. bacillaris, as well as L. plantarum and G. oxydans. Organic acids and volatile compounds were also determined. Malic and succinic acids were the main ones with values ranging from 8.49 g/L to 11.76 g/L and from 4.15 g/L to 7.73 g/L respectively, while citric acid was present at low concentrations (<0.2 g/L) in all samples. Esters and higher alcohols were the main volatile compounds detected followed by alkanes. This study permits to better understand the microbial communities associated to this product and could be considered a starting point for the definition of tailored starter cultures to improve the quality of Vino cotto preserving its typical traits
- …
