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International Journal of Systematic and... Jun 2018Wild flowers, and in particular, nectar of flowers, have been shown to be a rich reservoir of yeast biodiversity. In a taxonomic study of yeasts recovered from floral...
Wild flowers, and in particular, nectar of flowers, have been shown to be a rich reservoir of yeast biodiversity. In a taxonomic study of yeasts recovered from floral nectar in Morocco, nine strains were found to represent a novel species. Morphological and physiological characteristics and sequence analyses of the D1/D2 region of the large subunit rRNA gene as well as the internal transcribed spacer region showed that the novel species belonged to the genus Metschnikowia. The name Metschnikowia maroccana f.a., sp. nov. (EBDCdVMor24-1=CBS 15053=NRRL Y-63972) is proposed to accommodate this new species. Metschnikowia maroccana was isolated from floral nectar of Teucrium pseudochamaepitys, Teucrium polium and Gladiolus italicus. The ascosporic state of the novel species was not found. Metschnikowia maroccana was phylogenetically distinct from any currently recognized species and forms a well-supported subclade (bootstrap value 81 %) containing species associated with flowers and flower-visiting insects, including Metschnikowia gruessii, Metschnikowia lachancei and Metschnikowia vanudenii. The close genealogical relationship of M. maroccana with the M. gruessii clade is also consistent with the striking similarity of their 'aeroplane' cells morphologies and the lack of utilization of the α-glucoside trehalose. The ecology of these novel species and its probable endemicity are discussed.
Topics: Biodiversity; DNA, Fungal; DNA, Ribosomal Spacer; Flowers; Iridaceae; Metschnikowia; Morocco; Phylogeny; Plant Nectar; Sequence Analysis, DNA; Teucrium
PubMed: 29688165
DOI: 10.1099/ijsem.0.002784 -
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 -
Food Research International (Ottawa,... May 2021The 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,...
The 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.
Topics: Fermentation; Hanseniaspora; Metschnikowia; Saccharomycetales; Wine
PubMed: 33992330
DOI: 10.1016/j.foodres.2021.110311 -
AMB Express Jun 2023Chinese strong-flavour liquor is produced via a traditional solid-state fermentation strategy facilitated by live microorganisms in pit mud-based cellars. For the...
Chinese strong-flavour liquor is produced via a traditional solid-state fermentation strategy facilitated by live microorganisms in pit mud-based cellars. For the present analysis, pit mud samples from different spatial locations within fermentation cellars were collected, and the yeast communities therein were assessed via culture-based and denaturing gradient gel electrophoresis (DGGE) approaches. These analyses revealed significant differences in the composition of yeast communities present in different layers of pit mud. In total, 29 different yeast species were detected, and principal component analyses revealed clear differences in microbial diversity in pit mud samples taken from different cellar locations. Culture-dependent strategies similarly detected 20 different yeast species in these samples. However, while Geotrichum silvicola, Torulaspora delbrueckii, Hanseniaspora uvarum, Saturnispora silvae, Issatchenkia orientalis, Candida mucifera, Kazachstania barnettii, Cyberlindnera jadinii, Hanseniaspora spp., Alternaria tenuissima, Cryptococcus laurentii, Metschnikowia spp., and Rhodotorula dairenensis were detected via a PCR-DGGE approach, they were not detectable in culture-dependent analyses. In contrast, culture-based approaches led to the identification of Schizosaccharomyces pombe and Debaryomyces hansenii in these pit mud samples, whereas they were not detected using DGGE fingerprints profiles. An additional HS-SPME-GC-MS-based analysis of the volatile compounds present in fermented grains samples led to the identification of 66 such compounds, with the highest levels of volatile acids, esters, and alcohols being detected in fermented grains from lower layer samples. A canonical correspondence analysis (CCA) suggested they were significant correlations between pit mud yeast communities and associated volatile compounds in fermented grains.
PubMed: 37291367
DOI: 10.1186/s13568-023-01562-7 -
EFSA Journal. European Food Safety... Dec 2017The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, France, for the... (Review)
Review
The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, France, for the pesticide active substance NRRL Y-27328 and the assessment of the application for inclusion in Annex IV of Regulation (EU) No 396/2005 are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of NRRL Y-27328 as a fungicide on stone fruits, strawberries and grapes. The reliable endpoints, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.
PubMed: 32625375
DOI: 10.2903/j.efsa.2017.5084 -
International Journal of Food... Jan 2021Non-Saccharomyces yeasts have increasingly been used in vinification recently. This is particularly true of Torulaspora delbrueckii and Metschnikowia pulcherrima, which...
Non-Saccharomyces yeasts have increasingly been used in vinification recently. This is particularly true of Torulaspora delbrueckii and Metschnikowia pulcherrima, which are inoculated before S. cerevisiae, to complete a sequential alcoholic fermentation. This paper aims to study the effects of these two non-Saccharomyces yeasts on malolactic fermentation (MLF) carried out by two strains of Oenococcus oeni, under cellar conditions. Oenological parameters, and volatile and phenolic compounds were analysed in wines. The wines were tasted, and the microorganisms identified. In general, non-Saccharomyces created more MLF friendly conditions, largely because of lower concentrations of SO and medium chain fatty acids. The most favourable results were observed in wines inoculated with T. delbrueckii, that seemed to promote the development of O. oeni and improve MLF performance.
Topics: Fermentation; Lactic Acid; Malates; Metschnikowia; Oenococcus; Phenols; Torulaspora; Volatile Organic Compounds; Wine
PubMed: 33202298
DOI: 10.1016/j.ijfoodmicro.2020.108954 -
Philosophical Transactions of the Royal... Mar 2023One major concern related to climate change is that elevated temperatures will drive increases in parasite outbreaks. Increasing temperature is known to alter host...
One major concern related to climate change is that elevated temperatures will drive increases in parasite outbreaks. Increasing temperature is known to alter host traits and host-parasite interactions, but we know relatively little about how these are connected mechanistically-that is, about how warmer temperatures impact the relationship between epidemiologically relevant host traits and infection outcomes. Here, we used a zooplankton-fungus () disease system to experimentally investigate how temperature impacted physical barriers to infection and cellular immune responses. We found that reared at warmer temperatures had more robust physical barriers to infection but decreased cellular immune responses during the initial infection process. Infected hosts at warmer temperatures also suffered greater reductions in fecundity and lifespan. Furthermore, the relationship between a key trait-gut epithelium thickness, a physical barrier-and the likelihood of terminal infection reversed at warmer temperatures. Together, our results highlight the complex ways that temperatures can modulate host-parasite interactions and show that different defense components can have qualitatively different responses to warmer temperatures, highlighting the importance of considering key host traits when predicting disease dynamics in a warmer world. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
Topics: Animals; Daphnia; Temperature; Parasites; Host-Pathogen Interactions; Host-Parasite Interactions
PubMed: 36744571
DOI: 10.1098/rstb.2022.0009 -
FEMS Yeast Research Apr 2021Sterols are essential components of the yeast membrane and their synthesis requires oxygen. Yet, Saccharomyces cerevisiae has developed the ability to take up sterols...
Sterols are essential components of the yeast membrane and their synthesis requires oxygen. Yet, Saccharomyces cerevisiae has developed the ability to take up sterols from the medium under anaerobiosis. Here we investigated sterol uptake efficiency and the expression of genes related to sterol import in Saccharomyces and non-Saccharomyces wine yeast species fermenting under anaerobic conditions. The sterol uptake efficiency of 39 strains was evaluated by flow cytometry (with 25-NBD Cholesterol, a fluorescent cholesterol probe introduced in the medium) and we found an important discrepancy between Saccharomyces and non-Saccharomyces wine yeast species that we correlated to a lower final cell population and a lower fermentation rate. A high uptake of sterol was observed in the various Saccharomyces strains. Spot tests performed on 13 of these strains confirmed the differences between Saccharomyces and non-Saccharomyces strains, suggesting that the presence of the sterol uptake transporters AUS1 and PDR11 could cause these discrepancies. Indeed, we could not find any homologue to these genes in the genome of Hanseniaspora uvarum, H. guillermondii, Lachancea thermotolerans, Torulaspora delbreueckii, Metschnikowia pulcherrima, or Starmarella bacillaris species. The specialization of sterol import function for post genome-duplication species may have favored growth under anaerobiosis.
Topics: Anaerobiosis; Biological Transport; Fermentation; Phylogeny; Saccharomyces; Sterols; Wine; Yeasts
PubMed: 33852000
DOI: 10.1093/femsyr/foab020 -
Ecology and Evolution Mar 2018Yeast volatiles attract insects, which apparently is of mutual benefit, for both yeasts and insects. However, it is unknown whether biosynthesis of metabolites that...
Yeast volatiles attract insects, which apparently is of mutual benefit, for both yeasts and insects. However, it is unknown whether biosynthesis of metabolites that attract insects is a basic and general trait, or if it is specific for yeasts that live in close association with insects. Our goal was to study chemical insect attractants produced by yeasts that span more than 250 million years of evolutionary history and vastly differ in their metabolism and lifestyle. We bioassayed attraction of the vinegar fly to odors of phylogenetically and ecologically distinct yeasts grown under controlled conditions. Baker's yeast , the insect-associated species , and , wine yeast , milk yeast , the vertebrate pathogens and , and oleophilic were screened for fly attraction in a wind tunnel. Yeast headspace was chemically analyzed, and co-occurrence of insect attractants in yeasts and flowering plants was investigated through a database search. In yeasts with known genomes, we investigated the occurrence of genes involved in the synthesis of key aroma compounds. Flies were attracted to all nine yeasts studied. The behavioral response to baker's yeast was independent of its growth stage. In addition to , we tested the basal hexapod (Collembola) in a Y-tube assay to the most ancient yeast, which proved that early yeast signals also function on clades older than neopteran insects. Behavioral and chemical data and a search for selected genes of volatile metabolites underline that biosynthesis of chemical signals is found throughout the yeast clade and has been conserved during the evolution of yeast lifestyles. Literature and database reviews corroborate that yeast signals mediate mutualistic interactions between insects and yeasts. Moreover, volatiles emitted by yeasts are commonly found also in flowers and attract many insect species. The collective evidence suggests that the release of volatile signals by yeasts is a widespread and phylogenetically ancient trait, and that insect-yeast communication evolved prior to the emergence of flowering plants. Co-occurrence of the same attractant signals in yeast and flowers suggests that yeast-insect communication may have contributed to the evolution of insect-mediated pollination in flowers.
PubMed: 29531709
DOI: 10.1002/ece3.3905 -
Journal of Fish Diseases Jan 2022A severe disease occurred in farmed Eriocheir sinensis characterized by milky liquid accumulation in the pectoral cavity, in the province of Liaoning, China, during...
A severe disease occurred in farmed Eriocheir sinensis characterized by milky liquid accumulation in the pectoral cavity, in the province of Liaoning, China, during October 2018-April 2019. Diseased crabs moved sluggishly, exhibited appetite loss and readily lost legs. Under the microscopic analysis, it was observed that the milky liquid contained a large number of yeastlike microorganisms (0.8-1.2 μm × 1.5-1.9 μm), which were also present in the muscle, hepatopancreas and gills. A dominant strain was isolated from the milky liquid and other tissues of diseased crabs. It grew on nutrient agar and formed 1- to 3-mm white opaque colonies, each with a protuberance in the centre. Besides, the results of TEM and SEM also demonstrate a typical multilateral budding model of the yeast clearly. We identified the strain, which we named 2EJM001, as Metschnikowia bicuspidata based on 18S rDNA, ITS and 26S rDNA sequence analyses and on its morphological, physiological and biochemical characteristics. Phylogenetic analysis revealed that 26S rDNA of 2EJM001 was clustered with M. bicuspidata (LNES0119) as reported by Bao et al. In addition, unlike Bao et al., two challenge experiments (injection and immersion) were used in this study. The results of challenge experiments show that 2EJM001 was pathogenic to E. sinensis and caused signs similar to those found in the naturally infected crabs. At the same time, the minimum inhibitory concentrations (MIC and MIC ) were determined. This study further confirms that M. bicuspidata 2EJM001 was the pathogen responsible for 'milky disease' in E. sinensis from Liaoning Province.
Topics: Animals; Antifungal Agents; Brachyura; Fish Diseases; Metschnikowia; Phylogeny
PubMed: 34525224
DOI: 10.1111/jfd.13530