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Foods (Basel, Switzerland) Aug 2020The influence of fruit varieties on yeast ecology during spontaneous plum mash fermentation was investigated. Yeast colonies were isolated from mashes obtained from four...
The influence of fruit varieties on yeast ecology during spontaneous plum mash fermentation was investigated. Yeast colonies were isolated from mashes obtained from four plum varieties throughout fermentation in laboratory conditions during two consecutive years. The yeast strains were differentiated by random amplification of polymorphic DNA (RAPD-PCR) and identified by the 26S rDNA D1/D2 sequence analysis. , spp. and were the dominant yeasts during the early stages of plum mash fermentation, while the middle and end phases were dominated by . The strains of , , , and were also detected in fermenting plum mashes. sp. M1, H1 and H2 strains were detected in all samples, irrespective of the tested variety and year. Investigation of the impact of individual yeast strains on the production of volatile compounds showed the potential possibility of using them as starter cultures.
PubMed: 32759797
DOI: 10.3390/foods9081054 -
Foods (Basel, Switzerland) Oct 2022There is a lack of studies evaluating the metabolic contribution of non- yeasts in early fermentation phases. This study aimed to investigate the volatile aroma profiles...
There is a lack of studies evaluating the metabolic contribution of non- yeasts in early fermentation phases. This study aimed to investigate the volatile aroma profiles produced by various non- yeasts just before sequential inoculation with to provide an insight into the particular effects they induce at this stage. The grape must of Malvazija istarska was inoculated with monocultures of , , , , and , alongside a control. Eighty volatile compounds were quantified via headspace solid-phase microextraction and gas chromatography-mass spectrometry, and the data were statistically elaborated. Volatile profiles of non- yeasts differed significantly from the control. Most treatments caused increases in linalool and β-damascenone, decreases in higher alcohols and fatty acids, and improved synthesis of odoriferous esters. and produced compounds not commonly found in fermented wines. Multivariate statistical analysis linked the investigated yeasts to specific, particularly abundant compounds. Future studies should explore to what degree these contributions persist after sequential inoculation with in diverse grape must matrices.
PubMed: 36230163
DOI: 10.3390/foods11193088 -
Frontiers in Microbiology 2017The increasing level of hazardous residues in the environment and food chains has led the European Union to restrict the use of chemical fungicides. Thus, exploiting new...
The increasing level of hazardous residues in the environment and food chains has led the European Union to restrict the use of chemical fungicides. Thus, exploiting new natural antagonistic microorganisms against fungal diseases could serve the agricultural production to reduce pre- and post-harvest losses, to boost safer practices for workers and to protect the consumers' health. The main aim of this work was to evaluate the antagonistic potential of epiphytic yeasts against , and pathogen species. In particular, yeast isolation was carried out from grape berries of ssp sylvestris populations, of the Eurasian area, and ssp cultivars from three different farming systems (organic, biodynamic, and conventional). Strains able to inhibit or slow the growth of pathogens were selected by and experiments. The most effective antagonist yeast strains were subsequently assayed for their capability to colonize the grape berries. Finally, possible modes of action, such as nutrients and space competition, iron depletion, cell wall degrading enzymes, diffusible and volatile antimicrobial compounds, and biofilm formation, were investigated as well. Two hundred and thirty-one yeast strains belonging to 26 different species were isolated; 20 of them, ascribed to eight species, showed antagonistic action against all molds. Yeasts isolated from ssp sylvestris were more effective (up to 50%) against rather than those isolated from ssp vinifera. Six strains, all isolated from wild vines, belonging to four species (, and ) revealed one or more phenotypical characteristics associated to the analyzed modes of antagonistic action.
PubMed: 29163377
DOI: 10.3389/fmicb.2017.02025 -
Frontiers in Microbiology 2023The organoleptic profile and quality of wine are affected by the presence of different non-s species and strains. Therefore, the identification and characterization of...
The organoleptic profile and quality of wine are affected by the presence of different non-s species and strains. Therefore, the identification and characterization of non-s yeasts are the first step to understand their function, and to develop a better strain selection program for winemaking. This study investigated the biodiversity of non- yeasts associated with spontaneous fermentation of Cabernet Sauvignon wines from five sub-regions (Shi Zuishan, Yinchuan, Yu Quanying, Qing Tongxia and Hong Sibu) in Ningxia, China. Yeast species were identified by sequencing the 26S rRNA D1/D2 region, and strains at the subspecies level were discriminated using tandem repeat-tRNA (TRtRNA) PCR analysis. A total of 524 yeast colonies were isolated, and 19 non- yeast species belonging to 10 genera were identified, including , , sp., , , , , , sp., , , , , , , and . , , and were the three most dominated species, while other non- species were only present in the early stage of spontaneous fermentations at different levels. Further, for the yeast discrimination at strain level, 34 profiles were obtained by amplification with primer pairs TtRNASC/5CAG, while 40 profiles were obtained with primer pairs TtRNASC/ISSR-MB. This study explored the diversity of non- species in Ningxia, China, and made an important contribution of genetic resources for further strain development.
PubMed: 37664125
DOI: 10.3389/fmicb.2023.1253969 -
Journal of Food Science and Technology May 2017Ninety-seven non- wine yeast strains belonging to ten different genera and species ( spp. and spp.; , , , , and were screened for 13 enzymes related to wine aroma,...
Ninety-seven non- wine yeast strains belonging to ten different genera and species ( spp. and spp.; , , , , and were screened for 13 enzymes related to wine aroma, color and clarity. Understanding the yeasts' influence in these wine characteristics provides a platform for selecting strains for their development as starter cultures and for the management of alcoholic fermentation. Most of the strains showed the presence of one or more enzymes of biotechnological interest. Our screening demonstrated several intraspecific differences within the yeast species investigated, indicating that strain selection is of great importance for their enological application, and also that some non- that have not been thoroughly explored, may deserve further consideration. This research represents the first stage for selecting non- strains to be used as a starter along with to enhance some particular characteristics of wines.
PubMed: 28559615
DOI: 10.1007/s13197-017-2587-7 -
Antimicrobial Agents and Chemotherapy Jun 2020Manogepix (APX001A) is the active moiety of the novel drug candidate fosmanogepix (APX001). We previously reported the broad-spectrum activity of manogepix but also...
Manogepix (APX001A) is the active moiety of the novel drug candidate fosmanogepix (APX001). We previously reported the broad-spectrum activity of manogepix but also observed a correlation between increased manogepix and fluconazole MICs. Here, we extended this study and included isolates with acquired fluconazole resistance. Isolates ( = 835) were identified using CHROMagar, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and, when needed, internal transcribed spacer (ITS) sequencing. EUCAST E.Def 7.3.1 susceptibility testing included manogepix, amphotericin B, anidulafungin, micafungin, fluconazole, and voriconazole. Manogepix wild-type-upper-limit (WT-UL) values were established following EUCAST principles for the epidemiological cutoff value (ECOFF) setting allowing wild-type/non-wild-type classification. Drug-specific MIC correlations were investigated using Pearson's correlation. Manogepix modal MICs were low (range, 0.004 to 0.06 mg/liter against 16/20 included species). Exceptions were and and, to a lesser extent, and The activity was independent of Fks echinocandin hot spot alterations ( = 17). Adopting the WT-UL established for , , , , and , 14/724 (1.9%) isolates were non-wild type for manogepix. Twelve of these (85.7%) were also non-wild type for fluconazole. A statistically significant correlation was observed between manogepix and fluconazole MICs for , , , , and (Pearson's = 0.401 to 0.575) but not between manogepix and micafungin or amphotericin B MICs for any species except ( = 0.519 for manogepix versus micafungin). Broad-spectrum activity was confirmed for manogepix against contemporary yeast. However, a 1 to 4 2-fold dilutions increase in manogepix MICs is observed in a subset of isolates with acquired fluconazole resistance. Further studies on the potential underlying mechanism and implication for optimal dosing are warranted.
Topics: Aminopyridines; Antifungal Agents; Candida; Drug Resistance, Fungal; Fluconazole; Humans; Isoxazoles; Kluyveromyces; Microbial Sensitivity Tests; Pichia
PubMed: 32366708
DOI: 10.1128/AAC.00429-20 -
Microorganisms Jan 2022Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final...
Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final products. The present study investigated, for the first time, the microbiota of spontaneously fermented Maiorca dough samples collected from bakeries located in Sicily (Italy). Four sourdough samples (M1, M2, M3, and M4), were produced using Host. var. Koern (Maiorca grain) were subjected to LAB and yeasts isolation and identification at the species level. The in-depth characterization of the lactobacilli population revealed that and unquestionably dominated the Maiorca sourdough ecosystem. Concerning the yeasts community, high species diversity was found. and were the most frequently isolated species. In addition, and were also detected. Investigations on both pro-technological and functional traits of the isolated strains could lead to the selection of starters for the production of baked goods.
PubMed: 35208738
DOI: 10.3390/microorganisms10020283 -
BMC Microbiology Jan 2017While recent advances in next generation sequencing technologies have enabled researchers to readily identify countless microbial species in soil, rhizosphere, and...
BACKGROUND
While recent advances in next generation sequencing technologies have enabled researchers to readily identify countless microbial species in soil, rhizosphere, and phyllosphere microbiomes, the biological functions of the majority of these species are unknown. Functional studies are therefore urgently needed in order to characterize the plethora of microorganisms that are being identified and to point out species that may be used for biotechnology or plant protection. Here, we used a dual culture assay and growth analyses to characterise yeasts (40 different isolates) and their antagonistic effect on 16 filamentous fungi; comprising plant pathogens, antagonists, and saprophytes.
RESULTS
Overall, this competition screen of 640 pairwise combinations revealed a broad range of outcomes, ranging from small stimulatory effects of some yeasts up to a growth inhibition of more than 80% by individual species. On average, yeasts isolated from soil suppressed filamentous fungi more strongly than phyllosphere yeasts and the antagonistic activity was a species-/isolate-specific property and not dependent on the filamentous fungus a yeast was interacting with. The isolates with the strongest antagonistic activity were Metschnikowia pulcherrima, Hanseniaspora sp., Cyberlindnera sargentensis, Aureobasidium pullulans, Candida subhashii, and Pichia kluyveri. Among these, the soil yeasts (C. sargentensis, A. pullulans, C. subhashii) assimilated and/or oxidized more di-, tri- and tetrasaccharides and organic acids than yeasts from the phyllosphere. Only the two yeasts C. subhashii and M. pulcherrima were able to grow with N-acetyl-glucosamine as carbon source.
CONCLUSIONS
The competition assays and physiological experiments described here identified known antagonists that have been implicated in the biological control of plant pathogenic fungi in the past, but also little characterised species such as C. subhashii. Overall, soil yeasts were more antagonistic and metabolically versatile than yeasts from the phyllosphere. Noteworthy was the strong antagonistic activity of the soil yeast C. subhashii, which had so far only been described from a clinical sample and not been studied with respect to biocontrol. Based on binary competition assays and growth analyses (e.g., on different carbon sources, growth in root exudates), C. subhashii was identified as a competitive and antagonistic soil yeast with potential as a novel biocontrol agent against plant pathogenic fungi.
Topics: Antibiosis; Biological Control Agents; Candida; DNA, Fungal; Fungi; Genome, Fungal; Genome, Mitochondrial; High-Throughput Nucleotide Sequencing; Malus; Plant Roots; Plants; Rhizosphere; Soil; Soil Microbiology
PubMed: 28056814
DOI: 10.1186/s12866-016-0908-z -
Brazilian Journal of Biology = Revista... Nov 2018Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an...
Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp.
Topics: Adult; Antifungal Agents; Candida; Candidiasis, Invasive; Humans; Microbial Sensitivity Tests; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length
PubMed: 29412252
DOI: 10.1590/1519-6984.175635 -
Pathogens (Basel, Switzerland) Oct 2023Yeasts associated with lepidopteran pests have been shown to play a role in their survival, development, and oviposition preference. It has been demonstrated that...
Yeasts associated with lepidopteran pests have been shown to play a role in their survival, development, and oviposition preference. It has been demonstrated that combining these yeasts with existing biological control agents can enhance their efficacy. The tortricid is a phytosanitary pest in the South African citrus industry, with the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) being one of the components that can control this pest. Several yeast species were shown to be associated with larvae, which affected their behaviour and development. A series of detached fruit bioassays were performed to determine whether the combination of yeast with CrleGV enhances its efficacy. These assays included determining the optimal yeast/virus ratio, testing all isolated yeast species in combination with CrleGV, and further improving yeast/virus formulation by adding an adjuvant. The optimal yeast concentration to use alongside CrleGV was determined to be 10 cells·mL. , , , and in combination with CrleGV reduced larval survival compared to CrleGV alone. The addition of molasses and BREAK-THRU S 240 to . and . in combination with CrleGV did not notably improve their effectiveness; however, there was an observed decrease in larval survival. In future studies, field trials will be conducted with combinations of CrleGV and or . to investigate whether these laboratory findings can be replicated in orchard conditions.
PubMed: 37887753
DOI: 10.3390/pathogens12101237