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International Journal of Systematic and... Aug 2023The gut of xylophagous insects such as termites harbours various symbiotic micro-organisms, including many yeast species. In a taxonomic study of gut-associated yeasts,...
The gut of xylophagous insects such as termites harbours various symbiotic micro-organisms, including many yeast species. In a taxonomic study of gut-associated yeasts, two strains (ATS2.16 and ATS2.18) were isolated from the gut of the wood-feeding termite sp. in Maharashtra, India. Morphological and physiological characteristics and sequence analyses of the ITS and D1/D2 region of the large subunit rRNA gene revealed that these two strains represent a novel asexual ascomycetous yeast species in the genus . The species differs from some of its close affiliates in the genus in its inability to utilize ethanol and succinate as the sole carbon source and growth in high sugar concentrations (up to 50 % glucose). In contrast to most members of , the formation of ascospores was not observed on various sporulation media. Moreover, whole-genome sequencing was used to further confirm the novelty of this species. When compared with other large-spored species, average nucleotide identity values of 79-80 % and digital DNA-DNA hybridization values of 16-17 % were obtained. The name f.a., sp. nov. is proposed to accommodate this novel yeast species, with ATS2.16 as the holotype and strains NFCCI 4949, MTCC 13085 and PYCC 9152 as isotypes. The MycoBank number is MB 844210.
Topics: Animals; Metschnikowia; Isoptera; Wood; Phylogeny; Sequence Analysis, DNA; India; RNA, Ribosomal, 16S; DNA, Bacterial; Bacterial Typing Techniques; Base Composition; Fatty Acids; Yeasts; Porifera; DNA, Fungal; DNA, Ribosomal Spacer; Mycological Typing Techniques; Saccharomycetales
PubMed: 37540005
DOI: 10.1099/ijsem.0.006012 -
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 -
Antonie Van Leeuwenhoek Oct 2019This study set out to isolate and identify epiphytic yeasts producing pulcherrimin, and to evaluate their potential as biological control agents (BCAs). We isolated...
This study set out to isolate and identify epiphytic yeasts producing pulcherrimin, and to evaluate their potential as biological control agents (BCAs). We isolated Metschnikowia sp. strains from flowers and fruits collected in Poland. The plant material had been collected between April to September 2017 from two small orchards where traditional organic management is employed. We identified the essential phenotypic features of the yeast, including assimilation and enzymatic profiles, stress resistance, adhesion properties, and antimicrobial activity against various fungi involved in crop and/or food spoilage. Yeast screening was performed using YPD agar supplemented with chloramphenicol and Fe(III) ions. Taxonomic classification was determined by sequence analysis of the D1/D2 domains of the large subunit rRNA gene. The isolates were identified as Metschnikowia andauensis and Metschnikowia sinensis. The yeast isolates were further characterized based on their enzymatic and assimilation profiles, as well as their growth under various stress conditions. In addition, the hydrophobicity and adhesive abilities of the Metschnikowia isolates were determined using a MATH test and luminometry. Their antagonistic action against molds representing typical crop spoiling microflora was also evaluated. The assimilation profiles of the wild isolates were similar to those displayed by collection strains of M. pulcherrima. However, some of the isolates displayed more beneficial phenotypic properties, especially good growth under stress conditions. Several of the epiphytes grew well over a wider range of temperatures (8-30 °C) and pH levels (3-9), and additionally showed elevated tolerance to ethanol (8%), glucose (30%), and peroxides (50 mM). The hydrophobicity and adhesion of the yeast cells were strain- and surface-dependent. The tested yeasts showed potential for use as BCAs, with some exhibiting strong antagonism against molds belonging to the genera Alternaria, Botrytis, Fusarium, Rhizopus, and Verticillium, as well as against yeasts isolated as food spoilage microbiota.
Topics: Amino Acids, Sulfur; Antibiosis; Cluster Analysis; DNA, Fungal; DNA, Ribosomal; Flowers; Fruit; Fungi; Hydrogen-Ion Concentration; Metschnikowia; Mycological Typing Techniques; Pest Control, Biological; Phylogeny; Piperidines; Poland; RNA, Ribosomal; Sequence Analysis, DNA; Temperature
PubMed: 31111331
DOI: 10.1007/s10482-019-01272-w -
International Journal of Food... Nov 2021Metschnikowia citriensis FL01 has great potential for biocontrol applications for its excellent biocontrol efficacy on postharvest diseases of citrus fruit, and the iron...
Metschnikowia citriensis FL01 has great potential for biocontrol applications for its excellent biocontrol efficacy on postharvest diseases of citrus fruit, and the iron depletion by pulcherriminic acid (PA) and then formation of insoluble pigment pulcherrimin had been speculated as an important action mechanism. To identify the genes involved in pulcherrimin synthesis and reutilization in M. citriensis FL01, we de novo assembled the genome of M. citriensis FL01 based on long-read PacBio sequencing. The final assembled genome consisted of 12 contigs with a genome size of 25.74 Mb, G + C content of 49.16% and 9310 protein-coding genes. The genome-wide BLAST of the PUL genes of M. pulcherrima APC 1.2 showed that the four PUL genes were clustered and located on Contig 4 of M. citriensis FL01. In order to further clarify the role of pulcherrimin pigment on biocontrol of M. citriensis FL01, CRISPR/cas9 technology was used to knock out PUL2 gene that was responsible for PA synthesis and the pigmentless mutants with stable phenotype were obtained. The mutant strains of M. citriensis FL01 lost the ability to produce pulcherrimin pigment, and simultaneously lost the ability to inhibit the growth of Geotrichum citri-aurantii in vitro. Moreover, the biocontrol efficacy of pigmentless mutant strains against sour rot was about 80% lower than that of wild-type M. citriensis FL01. These results directly proved that the iron depletion was an important mechanism of M. citriensis FL01.
Topics: Citrus; Geotrichum; Iron; Metschnikowia
PubMed: 34517294
DOI: 10.1016/j.ijfoodmicro.2021.109384 -
Microorganisms Jan 2021is a non-conventional yeast with the potential to be used in biotechnological processes, especially involving low-cost feedstock exploitation. However, there are a lack...
is a non-conventional yeast with the potential to be used in biotechnological processes, especially involving low-cost feedstock exploitation. However, there are a lack of tools for researching it at a molecular level and for producing genetically modified strains. We tested the amenability to genetic modification of ten different strains, establishing a transformation protocol based on LiAc/PEG that allows us to introduce heterologous DNA. Non-homologous integration was broadly successful and homologous recombination was successful in two strains. Chemical inhibition of non-homologous end joining recombination had a modest effect on the improvement of homologous recombination rates. Removal of selective markers via flippase recombinase was successful across integrated loci except for those targeted to the native locus, suggesting that the genome sequence or structure alters the efficacy of this system.
PubMed: 33572537
DOI: 10.3390/microorganisms9020290 -
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 -
Microbiological Research Jan 2021The pathogenic yeast strain LIAO causing the milky disease in the Chinese mitten crab belonged to one member of Metschnikowia bicuspidate which could grow well at...
The pathogenic yeast strain LIAO causing the milky disease in the Chinese mitten crab belonged to one member of Metschnikowia bicuspidate which could grow well at different temperatures from 28 to 4 °C. It was also found that the pathogenic yeast strain LIAO could grow in the extracts of the muscle, gill, heart tissues, intestinal tracts of the healthy Chinese mitten crabs by using the reducing sugars, amino acids and other nutrients in them. Massoia lactone released from liamocins produced by Aureobasidium melanogenum had high anti-fungal activity against the pathogenic yeast strain LIAO and M. bicuspidate WCY isolated from the diseased marine crabs. The minimal inhibitory concentrations (MIC) and the minimal fungicidal concentration (MFC) in the liquid culture against the pathogenic yeast strain LIAO were 0.15 mg/mL and 0.34 mg/mL, respectively. Massoia lactone as a bio-surfactant could damage the cell membrane, even break the whole cells of the pathogenic yeast strain LIAO and cause cellular necrosis of the pathogenic yeast LIAO. Therefore, Massoia lactone could be used to effectively kill the pathogenic yeast strains and as an effectitve treatment for milky disease in the Chinese mitten crab.
Topics: Animal Diseases; Animals; Antifungal Agents; Aureobasidium; Base Sequence; Brachyura; Lactones; Metschnikowia; Microbial Sensitivity Tests; Necrosis; Phylogeny; Yeasts
PubMed: 33191103
DOI: 10.1016/j.micres.2020.126641 -
Molecules (Basel, Switzerland) Jun 2023Candidiasis is one of the most frequent infections worldwide. In this study, the antimicrobial properties of six strains belonging to the clade were evaluated against...
Candidiasis is one of the most frequent infections worldwide. In this study, the antimicrobial properties of six strains belonging to the clade were evaluated against twenty and -related var. (syn. ) of different origins, employing the agar cross method. The toxic effect of pulcherrimin, a red metabolite that is responsible for the antimicrobial activities of spp., was evaluated in various experimental models. The results of agar tests showed that the selected strains inhibited the growth of the and non- strains. However, inhibition was dependent on the strain and the environment. The presence of peptone, sodium silicate, and a higher incubation temperature decreased the antifungal action of the strains. Pulcherrimin showed cytotoxic and antiproliferative activity, with oxidative stress in cells leading to apoptosis. More research is needed on the mechanism of action of pulcherrimin on somatic cells.
Topics: Candida; Metschnikowia; Agar; Antifungal Agents; Anti-Infective Agents
PubMed: 37446724
DOI: 10.3390/molecules28135064 -
Yeast (Chichester, England) Nov 2016The purpose of this review is to introduce Metschnikowia to the yeast researcher community and to convince readers that the genus is a worthwhile object of study in...
The purpose of this review is to introduce Metschnikowia to the yeast researcher community and to convince readers that the genus is a worthwhile object of study in developmental biology, genetics, ecology and biotechnology. Metschnikowia sits at the foundation of modern immunology, having been instrumental in the discovery of animal phagocytosis. Some 81 species form a monophyletic group within the Metschnikowiaceae, which also include the smaller genus Clavispora and a few clades of Candida species. The family stands out by the habit of forming, by meiosis, only two ascospores, which in Metschnikowia are needle shaped. In some cases, the spores can reach enormous proportions, exceeding 200 µm in length; in others, ascus formation is preceded by the development of chlamydospores. The adaptive value of such features remains to be elucidated. Extensive genetic studies are lacking, but attempts to apply methods developed for model species have been successful. Some species are found at the plant-insect interface whereas others are pathogens of aquatic animals and have served as model organisms in the exploration of host-parasite theory. Some species are globally distributed and others exhibit extreme endemism. Many species are remarkably easy to recover by sampling their known habitats. M. pulcherrima and close relatives may play an important role in wine quality and produce pulcherrimin, an iron-dipeptide complex that can interfere with the growth of other microorganisms. Some symbiotic species incapable of growth in culture media have been assigned to the genus, but their kinship with the group remains to be demonstrated. Copyright © 2016 John Wiley & Sons, Ltd.
PubMed: 27599462
DOI: 10.1002/yea.3208 -
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