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Foods (Basel, Switzerland) May 2024This study explores the potential probiotic properties of yeasts isolated from various Chilean honeys, focusing on Ulmo, Quillay, and Mountain honeys. Six yeast strains...
This study explores the potential probiotic properties of yeasts isolated from various Chilean honeys, focusing on Ulmo, Quillay, and Mountain honeys. Six yeast strains were identified, including , sp., , , , and . Phenotypic characterization involved assessing their fermentative performance, ethanol and hops resistance, and cross-resistance. Ethanol concentration emerged as a limiting factor in their fermentative performance. The probiotic potential of these yeasts was evaluated based on resistance to high temperatures, low pH, auto-aggregation capacity, survival in simulated digestion (INFOGEST method), and antimicrobial activity against pathogens like , , and . Three yeasts, , , and , exhibited potential probiotic characteristics by maintaining cell concentrations exceeding 10 CFU/mL after digestion. They demonstrated fermentative abilities and resistance to ethanol and hops, suggesting their potential as starter cultures in beer production. Despite revealing promising probiotic and technological aspects, further research is necessary to ascertain their viability in producing fermented foods. This study underscores the innovative potential of honey as a source for new probiotic microorganisms and highlights the need for comprehensive investigations into their practical applications in the food industry.
PubMed: 38790882
DOI: 10.3390/foods13101582 -
Scientific Reports May 2024In molecular systematics, the delimitation of yeast species is based on the notion that the barcode differences are smaller within species than between them. The most...
In molecular systematics, the delimitation of yeast species is based on the notion that the barcode differences are smaller within species than between them. The most widely used barcodes are segments of the chromosomal repeats coding for ribosomal RNAs that are homogenised in yeasts. The analysis of these segments of the type strains of ten species recently merged in Metschnikowia pulcherrima and 37 new isolates demonstrated that this is not the case in this species. The intragenomic diversity significantly exceeded the threshold gaps used to differentiate related yeast species. Large segments of the D1/D2 domains were not diverse within the genomes and could therefore be used to determine the taxonomic affiliation of the isolates. The genome structures of the isolates were compared by RAPD and the RFLP of the mitochondrial DNA. Both patterns were highly heterogeneous. The sequence analysis of the PUL4 gene (a member of the PUL gene cluster involved in pulcherrimin production) revealed very high intragenomic differences, suggesting that the genomes may be chimerised. Three phenotypic traits related to the antimicrobial antagonism characteristic of the species were also highly diverse and prone to reversible segregation resembling epigenetic processes (silencing and reactivation of regulators) rather than mutations and back-mutations. These features make M. pulcherrima unique among yeasts and indicate that it evolves in a non-standard way.
Topics: Metschnikowia; Genome, Fungal; Evolution, Molecular; Phylogeny; Genetic Variation; Phenotype; DNA, Mitochondrial
PubMed: 38714828
DOI: 10.1038/s41598-024-61335-5 -
Ecology and Evolution Apr 2024Secondary metabolites produced by primary producers have a wide range of functions as well as indirect effects outside the scope of their direct target. Research...
Secondary metabolites produced by primary producers have a wide range of functions as well as indirect effects outside the scope of their direct target. Research suggests that protease inhibitors produced by cyanobacteria influence grazing by herbivores and may also protect against parasites of cyanobacteria. In this study, we asked whether those same protease inhibitors produced by cyanobacteria could also influence the interactions of herbivores with their parasites. We used the - zooplankton host-fungal parasite system to address this question because it is well documented that cyanobacteria protease inhibitors suppress trypsin and chymotrypsin in the gut of , and because it is known that infects via the gut. We tested the hypothesis that gut proteases are necessary for spores to be released from their asci. We then also tested whether diets that decrease trypsin and chymotrypsin activity in the guts of lead to lower levels of infection. Our results show that chymotrypsin promotes the release of the fungal spores from their asci. Moreover, a diet that strongly inhibited chymotrypsin activity in decreased infection levels, particularly in the most susceptible clones. Our results support the growing literature that cyanobacterial diets can be beneficial to zooplankton hosts when challenged by parasites and uncover a mechanism that contributes to the protective effect of cyanobacterial diets. Specifically, we demonstrate that host chymotrypsin enzymes promote the dehiscence of spores; when cyanobacteria inhibit the activity of chymotrypsin in hosts, this most likely traps the spore inside the ascus, preventing the parasite from puncturing the gut and beginning the infection process. This study illustrates how secondary metabolites of phytoplankton can protect herbivores against their own enemies.
PubMed: 38646007
DOI: 10.1002/ece3.11340 -
FEMS Yeast Research Jan 2024Although filamentous Ascomycetes may produce structures that are interpreted as male and female gametangia, ascomycetous yeasts are generally not considered to possess...
Although filamentous Ascomycetes may produce structures that are interpreted as male and female gametangia, ascomycetous yeasts are generally not considered to possess male and female sexes. In haplontic yeasts of the genus Metschnikowia, the sexual cycle begins with the fusion of two morphologically identical cells of complementary mating types. Soon after conjugation, a protuberance emerges from one of the conjugants, eventually maturing into an ascus. The originating cell can be regarded as an ascus mother cell, hence as female. We tested the hypothesis that the sexes, female or male, are determined by the mating types. There were good reasons to hypothesize further that mating type α cells are male. In a conceptually simple experiment, we observed the early stages of the mating reaction of mating types differentially labeled with fluorescent concanavalin A conjugates. Three large-spored Metschnikowia species, M. amazonensis, M. continentalis, and M. matae, were examined. In all three, the sexes were found to be independent of mating type, cautioning that the two terms should not be used interchangeably.
Topics: Genes, Mating Type, Fungal; Metschnikowia
PubMed: 38632043
DOI: 10.1093/femsyr/foae014 -
Heliyon Apr 2024, a novel endophytic yeast strain isolated from calyx, possesses strong antimicrobial activity. We investigated its potential use as an environmentally safe food...
, a novel endophytic yeast strain isolated from calyx, possesses strong antimicrobial activity. We investigated its potential use as an environmentally safe food biocontrol agent through genomics, transcriptomics, and metabolomics. Secondary metabolites were isolated from , followed by chemical structure elucidation, gene cluster identification, and RNA sequencing. Pulcherrimin was isolated using 2 M NaOH, its structure was confirmed, and the yield was quantified. Biocontrol efficacy of on persimmon fruits and calyx was evaluated by assessing lesion diameter and disease incidence. Following compounds were isolated from co-culture with and : fusaric acid, benzoic acid, benzeneacetic acid, 4-hydroxybenzeneacetic acid, 4-(-2-hydoxyethyl)-benzoic acid, cyclo (Leu-Leu), benzenemethanol, 4-hydroxy-benzaldehide, 2-hydroxy-4-methoxy-benzoic acid, 4-hydroxy-benzoic acid, lumichrome, heptadecanoic acid, and nonadecanoic acid. Exposing to different growth media conditions (with or without sugar) resulted in the isolation of five compounds: Tyrosol, Cyclo (Pro-Val), cyclo(L-Pro-L-Tyr), cyclo(Leu-Leu), and cyclo(l-tyrosilylicine). Differentially expressed gene analysis revealed 3264 genes that were significantly expressed (fold change ≥2 and p-value ≤0.05) during growth in different media, of which only 270 (8.27%) showed altered expression in all sample combinations with Luria-Bertani Agar as control. Minimal media with ferric ions and tween-80 triggered the most gene expression changes, with the highest levels of gene expression and pulcherrimin yield (262.166 mg/L) among all media treatments. also produced a higher amount of pulcherrimin (209.733 mg/L) than (152.8 mg/L). inhibited the growth of in persimmon fruit and calyx. Toxicity evaluation of extracts showed no harmful effects on the liver and mitochondria of zebrafish, and no potential risk of cardiotoxicity in hERG-HEK293 cell lines. Thus, can be commercialized as a potent and safe biocontrol agent for preserving food products.
PubMed: 38571591
DOI: 10.1016/j.heliyon.2024.e28464 -
World Journal of Microbiology &... Mar 2024Probiotic microorganisms are used to improve the health and wellness of people and the research on this topic is of current relevance and interest. Fifty-five yeasts,...
Probiotic microorganisms are used to improve the health and wellness of people and the research on this topic is of current relevance and interest. Fifty-five yeasts, coming from honeybee's ecosystem and belonging to Candida, Debaryomyces, Hanseniaspora, Lachancea, Metschnikowia, Meyerozyma, Starmerella and Zygosacchromyces genera and related different species, were evaluated for the probiotic traits. The resistance to gastrointestinal conditions, auto-aggregation, cell surface hydrophobicity or biofilm formation abilities as well as antimicrobial activity against common human pathogenic bacteria were evaluated. The safety analysis of strains was also carried out to exclude any possible negative effect on the consumer's health. The influence of proteinase treatment of living yeasts and their adhesion to Caco-2 cells were also evaluated. The greatest selection occurred in the first step of survival at the acidic pH and in the presence of bile salts, where more than 50% of the strains were unable to survive. Equally discriminating was the protease test which allowed the survival of only 27 strains belonging to the species Hanseniaspora guilliermondii, Hanseniaspora uvarum, Metschnikowia pulcherrima, Metschnikowia ziziphicola, Meyerozyma caribbica, Meyerozyma guilliermondii, Pichia kluyveri, Pichia kudriavzevii and Pichia terricola. An integrated analysis of the results obtained allowed the detection of seven yeast strains with probiotic aptitudes, all belonging to the Meyerozyma genus, of which three belonging to M. guillermondii and four belonging to M. caribbica species.
Topics: Bees; Animals; Humans; Ecosystem; Caco-2 Cells; Yeasts; Candida; Probiotics
PubMed: 38538981
DOI: 10.1007/s11274-024-03941-z -
Microbiological Research Jun 2024Saccharomycopsis species are natural organic sulphur auxotrophs. Their genomes do not encode genes for the uptake and assimilation of sulphate and thus these species...
Saccharomycopsis species are natural organic sulphur auxotrophs. Their genomes do not encode genes for the uptake and assimilation of sulphate and thus these species cannot grow on media lacking e.g. methionine. Due to the similarity between sulphate and selenate, uptake and assimilation of selenate occurs through the same pathway starting from sulphate transporters encoded by the homologs of the SUL1 and SUL2 genes in S. cerevisiae. Lack of these transporters renders Saccharomycopsis species resistant to selenate levels that are toxic to other microorganisms. We used this feature to enrich environmental samples for Saccharomycopsis species. This led to the isolation of S. schoenii, S. lassenensis and a hitherto undescribed Saccharomycopsis species with limited by-catch of other yeasts, mainly belonging to Metschnikowia and Hanseniaspora. We performed growth and predation assays to characterize the potential of these new isolates as predacious yeasts. Most Saccharomycopsis species are temperature sensitive and cannot grow at 37°C; with the exception of S. lassenensis strains. Predation assays with S. schoenii and S. cerevisiae as prey indicated that predation was enhanced at 20°C compared to 30°C. We crossed an American isolate of S. schoenii with our German isolate using marker directed breeding. Viable progeny indicated that both strains are interfertile and belong to the same biological species. S. lassenensis is heterothallic, while S. schoenii and the new Saccharomycopsis isolate, for which we suggest the name S. geisenheimensis sp. nov., are homothallic.
Topics: Saccharomycopsis; Saccharomyces cerevisiae; Selenic Acid; Biological Transport; Sulfates; Sulfate Transporters; Saccharomyces cerevisiae Proteins; Anion Transport Proteins
PubMed: 38492364
DOI: 10.1016/j.micres.2024.127691 -
Foods (Basel, Switzerland) Feb 2024As a biological alternative to the antimicrobial action of SO, bioprotection has been proposed to winemakers as a means to limit or prevent grape musts microbial...
As a biological alternative to the antimicrobial action of SO, bioprotection has been proposed to winemakers as a means to limit or prevent grape musts microbial alteration. Competition for nitrogenous nutrients and for oxygen are often cited as potential explanations for the effectiveness of bioprotection. This study analyses the effect of a bioprotective strain on the growth of one strain and one strain. Bioprotection efficiency was observed only against inoculated at the two lowest concentrations. These results indicate a potential species-dependent efficiency of the bioprotective strain and a strong impact of the initial ratio between bioprotective and apiculate yeasts. The analysis of the consumption of nitrogen compounds revealed that leucine, isoleucine, lysine and tryptophan were consumed preferentially by all three strains. The weaker assimilation percentages of these amino acids observed in at 24 h growth suggest competition with that could negatively affects the growth of the apiculate yeast in co-cultures. The slowest rate of O consumption of strain, in comparison with , was probably not involved in the bioprotective effect. Non-targeted metabolomic analyses of and co-culture indicate that the interaction between both strains particularly impact lysin and tryptophan metabolisms.
PubMed: 38472837
DOI: 10.3390/foods13050724 -
PloS One 2024To assess the possible impact of climatic variation on microbial community composition in organic winemaking, we employed a metabarcoding approach to scrutinize the...
To assess the possible impact of climatic variation on microbial community composition in organic winemaking, we employed a metabarcoding approach to scrutinize the microbiome in a commercial, organic, Pinot noir wine production system that utilizes autochthonous fermentation. We assessed microbial composition across two vintages (2018 and 2021) using biological replicates co-located at the same winery. Microbial dynamics were monitored over four important fermentation time points and correlated with contemporaneous climate data. Bacterial (RANOSIM = 0.4743, p = 0.0001) and fungal (RANOSIM = 0.4738, p = 0.0001) compositions were different in both vintages. For bacteria, Lactococcus dominated the diversity associated with the 2018 vintage, while Tatumella dominated the 2021 vintage. For fungal populations, while Saccharomyces were abundant in both vintages, key differences included Starmerella, copious in the 2018 vintage; and Metschnikowia, substantive in the 2021 vintage. Ordination plots correlated the climatic variables with microbial population differences, indicating temperature as a particularly important influence; humidity values also differed significantly between these vintages. Our data illustrates how climatic conditions may influence microbial diversity during winemaking, and further highlights the effect climate change could have on wine production.
Topics: Wine; Saccharomyces; Bacteria; Microbiota; Fermentation; Vitis
PubMed: 38416719
DOI: 10.1371/journal.pone.0296859 -
Food Research International (Ottawa,... Mar 2024Understanding fungal community dynamics during fermentation is important for assessing their influence on wine's phenolic content. The present study represents the first...
Understanding fungal community dynamics during fermentation is important for assessing their influence on wine's phenolic content. The present study represents the first effort to explore the correlation between the autochthonous mycobiota of Maraština grapes collected from Dalmatian winegrowing sub-regions in Croatia and the phenolic composition, as well as the physicochemical parameters of wines produced through spontaneous fermentation. The metataxonomic approach revealed Metschnikowia pulcherrima, Metschnikowia fructicola and Hanseniaspora uvarum as the core mycobiota detected at the initial phase of fermentation. By contrast, Saccharomyces cerevisiae took over the dominance starting from the middle stage of fermentation. The wine's phenolic compounds were revealed by high-performance liquid chromatography, with tyrosol being the most abundant. Rhodotorula babjevae and Botrytis cinerea showed a positive correlation with p-hydroxybenzoic acid, gentisic acid, caffeic acid and cinnamic acid, while demonstrating a negative correlation with protocatechuic acid and chlorogenic acid. Heterophoma novae-verbascicola exhibited the opposite behaviour regarding the same phenolic compounds. The concentration of lactic acid was positively correlated with B. cinerea and negatively correlated with Het. novae-verbascicola. These findings serve as a foundation for in-depth investigations into the role of autochthonous grape mycobiota in phenolic transformation during spontaneous fermentation, potentially leading to the production of high-quality wines with unique terroir characteristics. Future studies should aim to explore the specific role played by individual yeast isolates in the formation of phenolic compounds.
Topics: Wine; Fermentation; Vitis; Saccharomyces cerevisiae; Phenols
PubMed: 38395560
DOI: 10.1016/j.foodres.2024.114072