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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 -
Journal of Agricultural and Food... Dec 2023The structure of yeast cell wall (CW) mannoproteins (MPs) influences their impact on wine properties. Yeast species produce a diverse range of MPs, but the link between...
The structure of yeast cell wall (CW) mannoproteins (MPs) influences their impact on wine properties. Yeast species produce a diverse range of MPs, but the link between properties and specific structural features has been ill-characterized. This study compared the protein and polysaccharide moieties of MP-rich preparations from four strains of four different enologically relevant yeast species, named (SB62), (SC01), (MF77), and (TD70), and a commercial MP preparation. Monosaccharide determination revealed that SB62 MPs contained the highest mannose/glucose ratio followed by SC01, while polysaccharide size distribution analyses showed maximum molecular weights ranging from 1349 kDa for MF77 to 483 kDa for TD70. Protein identification analysis led to the identification of unique CW proteins in SB62, SC01, and TD70, as well as some proteins shared between different strains. This study reveals MP composition diversity within wine yeasts and paves the way toward their industrial exploitation.
Topics: Saccharomyces cerevisiae; Wine; Phylogeny; Fermentation; Polysaccharides
PubMed: 38049383
DOI: 10.1021/acs.jafc.3c05742 -
Journal of Applied Microbiology Dec 2023To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and...
AIMS
To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and threatens yields, and to assess the impacts of floral microbes and Colletotrichum pathogens on artificial nectar sugars and honey bee consumption.
METHODS AND RESULTS
The growth inhibition of Colletotrichum (Colletotrichum acutatum, Colletotrichum fioriniae, and Colletotrichum gloeosporioides) was screened using both artificial nectar co-culture and dual culture plate assays. All candidate nectar microbes were screened for antagonism against a single C. acutatum isolate. Then, the top four candidate nectar microbes showing the strongest inhibition of C. acutatum (Neokomagataea thailandica, Neokomagataea tanensis, Metschnikowia rancensis, and Symmetrospora symmetrica) were evaluated for antagonism against three additional C. acutatum isolates, and single isolates of both C. fioriniae and C. gloeosporioides. In artificial nectar assays, single and three-species cultures inhibited the growth of two of four C. acutatum isolates by ca. 60%, but growth of other Colletotrichum species was not affected. In dual culture plate assays, inhibition was observed for all Colletotrichum species for at least three of four selected microbial antagonists (13%‒53%). Neither honey bee consumption of nectar nor nectar sugar concentrations were affected by any microbe or pathogen tested.
CONCLUSIONS
Selected floral microbes inhibited growth of all Colletotrichum species in vitro, although the degree of inhibition was specific to the assay and pathogen examined. In all microbial treatments, nectar sugars were preserved, and honey bee preference was not affected.
Topics: Animals; Bees; Plant Nectar; Colletotrichum; Blueberry Plants; Biological Assay; Sugars
PubMed: 38061796
DOI: 10.1093/jambio/lxad300 -
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 -
BMC Bioinformatics Nov 2023Use of alternative non-Saccharomyces yeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety...
BACKGROUND
Use of alternative non-Saccharomyces yeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety of flavours in the product and to reduce the final alcohol content. Given the metabolic differences between the yeast species, we wanted to account for some of the differences by using in silico models.
RESULTS
We created and studied genome-scale metabolic models of five different non-Saccharomyces species using an automated processes. These were: Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora osmophila, Torulaspora delbrueckii and Kluyveromyces lactis. Using the models, we predicted that M. pulcherrima, when compared to the other species, conducts more respiration and thus produces less fermentation products, a finding which agrees with experimental data. Complex I of the electron transport chain was to be present in M. pulcherrima, but absent in the others. The predicted importance of Complex I was diminished when we incorporated constraints on the amount of enzymatic protein, as this shifts the metabolism towards fermentation.
CONCLUSIONS
Our results suggest that Complex I in the electron transport chain is a key differentiator between Metschnikowia pulcherrima and the other yeasts considered. Yet, more annotations and experimental data have the potential to improve model quality in order to increase fidelity and confidence in these results. Further experiments should be conducted to confirm the in vivo effect of Complex I in M. pulcherrima and its respiratory metabolism.
Topics: Yeasts; Metschnikowia; Torulaspora; Wine; Fermentation
PubMed: 37990145
DOI: 10.1186/s12859-023-05506-7 -
Antonie Van Leeuwenhoek Dec 2023Family Chrysopidae is known to harbor specific gut yeasts. However, no studies have been conducted outside of a limited number of these green lacewing species, and the...
Family Chrysopidae is known to harbor specific gut yeasts. However, no studies have been conducted outside of a limited number of these green lacewing species, and the diversity of yeasts in the family as a whole is not known. Therefore, we collected 58 Chrysopidae adults (9 species, 6 genera, 2 subfamilies) in Japan and isolated yeasts from all individuals. The results showed for the first time that not only subfamily Chrysopinae but also subfamily Apochrysinae have gut yeasts. We obtained 58 yeast isolates (one from each host individual), all of which were of the genus Metschnikowia. 28S rDNA- and ITS-based phylogenetic analysis showed that the isolates were divided into three clades, designated clade I, II, and III. Clade I contains two previously described Chrysopidae gut yeasts (M. picachoensis and M. pimensis) as well as a one of our new species named M. shishimaru. Clade II is a new clade, with at least two new species named M. kenjo and M. seizan. Clade III contains the previously described species M. noctiluminum, a Chrysopidae gut yeast, and one of our isolate (We have not described it as new species). However, the phylogenetic relationship between our isolate and M. noctiluminum was unclear. These results indicate that the Japanese Chrysopidae gut yeasts consist mainly of three undescribed species and that they are more unique than those found in previous surveys. The results of this study indicate that Chrysopidae gut yeasts are more diverse than previously thought and should be investigated in various geographical regions in the future.
Topics: Humans; Animals; Metschnikowia; Phylogeny; Japan; Yeasts; Porifera
PubMed: 37755530
DOI: 10.1007/s10482-023-01887-0 -
Intraspecific variation in realized dispersal probability and host quality shape nectar microbiomes.The New Phytologist Nov 2023Epiphytic microbes frequently affect plant phenotype and fitness, but their effects depend on microbe abundance and community composition. Filtering by plant traits and...
Epiphytic microbes frequently affect plant phenotype and fitness, but their effects depend on microbe abundance and community composition. Filtering by plant traits and deterministic dispersal-mediated processes can affect microbiome assembly, yet their relative contribution to predictable variation in microbiome is poorly understood. We compared the effects of host-plant filtering and dispersal on nectar microbiome presence, abundance, and composition. We inoculated representative bacteria and yeast into 30 plants across four phenotypically distinct cultivars of Epilobium canum. We compared the growth of inoculated communities to openly visited flowers from a subset of the same plants. There was clear evidence of host selection when we inoculated flowers with synthetic communities. However, plants with the highest microbial densities when inoculated did not have the highest microbial densities when openly visited. Instead, plants predictably varied in the presence of bacteria, which was correlated with pollen receipt and floral traits, suggesting a role for deterministic dispersal. These findings suggest that host filtering could drive plant microbiome assembly in tissues where species pools are large and dispersal is high. However, deterministic differences in microbial dispersal to hosts may be equally or more important when microbes rely on an animal vector, dispersal is low, or arrival order is important.
Topics: Animals; Plant Nectar; Pollination; Flowers; Plants; Microbiota; Saccharomyces cerevisiae; Bacteria
PubMed: 37614102
DOI: 10.1111/nph.19195 -
Folia Microbiologica Apr 2024Patients with burn injury and inhalation injury are highly susceptible to infectious complications, including opportunistic pathogens, due to the loss of skin cover and...
Patients with burn injury and inhalation injury are highly susceptible to infectious complications, including opportunistic pathogens, due to the loss of skin cover and mucosal damage of respiratory tract as well as the disruption of homeostasis. This case report, a 34-year-old man suffered critical burns, provides the first literature description of triple-impact immunoparalysis (critical burns, inhalation injury, and SARS-CoV-2 infection), leading to a lethal multifocal infection caused by several fungi including very rare environmental representatives Metschnikowia pulcherrima and Wickerhamomyces anomalus. The co-infection by these common environmental yeasts in a human is unique and has not yet been described in the literature. Importantly, our patient developed refractory septic shock and died despite targeted antifungal therapy including the most potent current antifungal agent-isavuconazole. It can be assumed that besides immunoparalysis, effectiveness of therapy by isavuconazole was impaired by the large distribution volume in this case. As this is a common situation in intensive care patients, routine monitoring of plasmatic concentration of isavuconazole can be helpful in personalization of the treatment and dose optimization. Whatmore, many fungal species often remain underdiagnosed during infectious complications, which could be prevented by implementation of new methods, such as next-generation sequencing, into clinical practice.
PubMed: 38647991
DOI: 10.1007/s12223-024-01165-0 -
Foods (Basel, Switzerland) Oct 2023Three strains marketed as bioprotection yeasts were studied to compare their antimicrobial effect on a mixture of two yeast strains in synthetic must at 12 °C,...
Three strains marketed as bioprotection yeasts were studied to compare their antimicrobial effect on a mixture of two yeast strains in synthetic must at 12 °C, mimicking pre-fermentative maceration by combining different approaches. The growth of the different strains was monitored, their nitrogen and oxygen requirements were characterised, and their metabolomic footprint in single and co-cultures studied. Only the strain and one strains colonised the must and induced the rapid decline of . The efficiency of these two strains followed different inhibition kinetics. Furthermore, the initial ratio between and was an important factor to ensure optimal bioprotection. Nutrient consumption kinetics showed that apiculate yeasts competed with strains for nutrient accessibility. However, this competition did not explain the observed bioprotective effect, because of the considerable nitrogen content remaining on the single and co-cultures. The antagonistic effect of on probably implied another form of amensalism. For the first time, metabolomic analyses of the interaction in a bioprotection context were performed after the pre-fermentative maceration step. A specific footprint of the interaction was observed, showing the strong impact of the interaction on the metabolic modulation of the yeasts, especially on the nitrogen and vitamin pathways.
PubMed: 37959046
DOI: 10.3390/foods12213927 -
Food Microbiology Oct 2023Considering the growing interest in non-Saccharomyces wine yeasts, and notably in the context of mixed fermentations with S. cerevisiae, understanding their nutritional...
Considering the growing interest in non-Saccharomyces wine yeasts, and notably in the context of mixed fermentations with S. cerevisiae, understanding their nutritional behaviors is essential to ensure better management of these fermentations. The vitaminic consumption of three non-Saccharomyces yeasts (Starmerella bacillaris, Metschnikowia pulcherrima and Torulaspora delbrueckii) was investigated during their growth in wine-like conditions, providing initial evidence that they consume different vitamers. The vitamin consumption profiles during their growth highlighted releases of certain vitamers by the yeasts before re-assimilation, strongly suggesting the existence of synthesis pathways. Not only did the essential character of vitamin B1, in particular, appear to be a trait common to these yeasts, since all its vitamers are consumed, this investigation also provided evidence of the existence of species-dependent preferences for their vitaminic sources. These different behaviors were quite striking in certain vitamers, as was observed in nicotinamide: while it was consumed by T. delbrueckii, it was left untouched by S. bacillaris and produced by M. pulcherrima during growth. Furthermore, this offers grounds for further investigation into these yeasts' requirements, and provides the first tool for managing vitamin resources during mixed fermentations with S. cerevisiae, and for preventing nutritive deficiencies from occurring.
PubMed: 37567637
DOI: 10.1016/j.fm.2023.104332