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Microbial Ecology Oct 2023Bats are widespread mammals that play key roles in ecosystems as pollinators and insectivores. However, there is a paucity of information about bat-associated microbes,...
Bats are widespread mammals that play key roles in ecosystems as pollinators and insectivores. However, there is a paucity of information about bat-associated microbes, in particular their fungal communities, despite the important role microbes play in host health and overall host function. The emerging fungal disease, white-nose syndrome, presents a potential challenge to the bat microbiome and understanding healthy bat-associated taxa will provide valuable information about potential microbiome-pathogen interactions. To address this knowledge gap, we collected 174 bat fur/skin swabs from 14 species of bats captured in five locations in New Mexico and Arizona and used high-throughput sequencing of the fungal internal transcribed (ITS) region to characterize bat-associated fungal communities. Our results revealed a highly heterogeneous bat mycobiome that was structured by geography and bat species. Furthermore, our data suggest that bat-associated fungal communities are affected by bat foraging, indicating the bat skin microbiota is dynamic on short time scales. Finally, despite the strong effects of site and species, we found widespread and abundant taxa from several taxonomic groups including the genera Alternaria and Metschnikowia that have the potential to be inhibitory towards fungal and bacterial pathogens.
Topics: Animals; Mycobiome; Chiroptera; Fungi; Microbiota; Geography
PubMed: 37126126
DOI: 10.1007/s00248-023-02230-w -
Food Research International (Ottawa,... Nov 2023The reduction of chemical inputs in wine has become one of the main challenges of the wine industry. One of the alternatives to sulfites developed is bioprotection,...
The reduction of chemical inputs in wine has become one of the main challenges of the wine industry. One of the alternatives to sulfites developed is bioprotection, which consists in using non-Saccharomyces strains to prevent microbial deviation. However, the impact of substituting sulfites by bioprotection on the final wine remains poorly studied. For the first time, we characterized this impact on Chardonnay wine through an integrative approach. Interestingly, physico-chemical analysis did not reveal any difference between both treatments regarding classical oenological parameters. Nevertheless, bioprotection did not seem to provide as much protection against oxidation as sulfites, as observed through phenolic compound analysis. At a deeper level, untargeted metabolomic analyses revealed substantial changes in wine composition according to must treatment. In particular, the specific footprint of each treatment revealed an impact on nitrogen-containing compounds. This observation could be related to modifications in S. cerevisiae metabolism, in particular amino acid biosynthesis and tryptophan metabolism pathways. Thus, the type of must treatment seemed to impact metabolic fluxes of yeast differently, leading to the production of different compounds. For example, we observed glutathione and melatonin, compounds with antioxidant properties, which were enhanced with sulfites, but not with bioprotection. However, despite substantial modifications in wines regarding their chemical composition, the change in must treatment did not seem to impact the sensory profile of wine. This integrative approach has provided relevant new insights on the impact of sulfite substitution by bioprotection on Chardonnay wines.
Topics: Sulfites; Saccharomyces cerevisiae; Fermentation; Wine; Metabolomics
PubMed: 37803722
DOI: 10.1016/j.foodres.2023.113383 -
Ecology Jul 2023The healthy herds hypothesis proposes that predators can reduce parasite prevalence and thereby increase the density of their prey. However, evidence for such...
The healthy herds hypothesis proposes that predators can reduce parasite prevalence and thereby increase the density of their prey. However, evidence for such predator-driven reductions in the prevalence of prey remains mixed. Furthermore, even less evidence supports increases in prey density during epidemics. Here, we used a planktonic predator-prey-parasite system to experimentally test the healthy herds hypothesis. We manipulated density of a predator (the phantom midge, Chaoborus punctipennis) and parasitism (the virulent fungus Metschnikowia bicuspidata) in experimental assemblages. Because we know natural populations of the prey (Daphnia dentifera) vary in susceptibility to both predator and parasite, we stocked experimental populations with nine genotypes spanning a broad range of susceptibility to both enemies. Predation significantly reduced infection prevalence, eliminating infection at the highest predation level. However, lower parasitism did not increase densities of prey; instead, prey density decreased substantially at the highest predation levels (a major density cost of healthy herds predation). This density result was predicted by a model parameterized for this system. The model specifies three conditions for predation to increase prey density during epidemics: (i) predators selectively feed on infected prey, (ii) consumed infected prey release fewer infectious propagules than unconsumed prey, and (iii) sufficiently low infection prevalence. While the system satisfied the first two conditions, prevalence remained too high to see an increase in prey density with predation. Low prey densities caused by high predation drove increases in algal resources of the prey, fueling greater reproduction, indicating that consumer-resource interactions can complicate predator-prey-parasite dynamics. Overall, in our experiment, predation reduced the prevalence of a virulent parasite but, at the highest levels, also reduced prey density. Hence, while healthy herds predation is possible under some conditions, our empirical results make it clear that the manipulation of predators to reduce parasite prevalence may harm prey density.
Topics: Animals; Predatory Behavior; Population Density; Food Chain
PubMed: 37186234
DOI: 10.1002/ecy.4063 -
Journal of Chemical Ecology May 2024Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits...
Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including β-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, β-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable.
PubMed: 38691267
DOI: 10.1007/s10886-024-01494-x -
Foods (Basel, Switzerland) Dec 2023Interest in () is growing in the world of winemaking. is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we...
Interest in () is growing in the world of winemaking. is used both to protect musts from microbial spoilage and to modulate the aromatic profile of wines. Here, we describe the isolation, characterization, and use of an autochthonous strain of in the vinification of Chasselas musts from the 2022 vintage. was used in co-fermentation with at both laboratory and experimental cellar scales. Our results showed that does not ferment sugars but has high metabolic activity, as detected by flow cytometry. Furthermore, sensory analysis showed that contributed slightly to the aromatic profile when compared to the control vinifications. The overall results suggest that our bioprospecting strategy can guide the selection of microorganisms that can be effectively used in the winemaking process.
PubMed: 38137289
DOI: 10.3390/foods12244485 -
Fish & Shellfish Immunology Feb 2024DM9-containing protein in invertebrates functions as pattern recognition receptor (PRR) to play significant roles in innate immunity. In the present study, a novel...
DM9-containing protein in invertebrates functions as pattern recognition receptor (PRR) to play significant roles in innate immunity. In the present study, a novel DM9-containg protein (defined as EsDM9CP-1) was identified from the Chinese mitten crab Eriocheir sinensis. EsDM9CP-1 is composed of 330 amino acids containing a Methyltransf_FA domain and two tandem DM9 repeats. The deduced amino acid sequence of EsDM9CP-1 shared low similarity with the previously identified DM9CPs from other species, and it was closely clustered with Platyhelminthes DM9CPs and then assigned into the branch of invertebrate DM9CPs in the unrooted phylogenetic tree. The mRNA transcripts of EsDM9CP-1 were highly expressed in haemocytes, gill, and heart. After Aeromonas hydrophila stimulation, the expression levels of EsDM9CP-1 mRNA in haemocytes increased significantly at 3 h (3.88-fold, p < 0.05) and 6 h (2.71-fold, p < 0.05), compared with that of PBS group, respectively. EsDM9CP-1 protein was mainly distributed in the cytoplasm and membrane of haemocytes. The recombinant EsDM9CP-1 protein (rEsDM9CP-1) exhibited binding affinity to MAN, PGN, LPS and Poly (I:C), and also to Gram-positive bacteria (Staphylococcus aureus, Micrococcus luteus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli, A. hydrophila and Vibrio splendidus) and fungi (Pichia pastoris and Metschnikowia bicuspidata) in a Ca-dependent manner. It was able to agglutinate A. hydrophila, S. aureus, M. luteus, M. bicuspidata and P. pastoris, and inhibit the growth of A. hydrophila and M. bicuspidate. These results suggested that EsDM9CP-1 in crab not only functioned as a PRR, but also agglutinated and inhibited the growth of microbes.
Topics: Humans; Animals; Phylogeny; Staphylococcus aureus; Base Sequence; Receptors, Pattern Recognition; Immunity, Innate; RNA, Messenger; Brachyura; Hemocytes
PubMed: 38163495
DOI: 10.1016/j.fsi.2023.109356 -
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 -
Ecology and Evolution Aug 2023While vertebrate immune systems are appreciated for their complexity and adaptability, invertebrate immunity is often considered to be less complex. However, immune...
While vertebrate immune systems are appreciated for their complexity and adaptability, invertebrate immunity is often considered to be less complex. However, immune responses in many invertebrates likely involve sophisticated processes. Interactions between the crustacean host and its fungal pathogen provide an excellent model for exploring the mechanisms underlying crustacean immunity. To explore the genomic basis of immunity in , we used RNA-sequencing technology to quantify differential gene expression between individuals of a single host genotype exposed or unexposed to over 24 h. Transcriptomic analyses showed that the number of differentially expressed genes between the control (unexposed) and experimental (exposed) groups increased over time. Gene ontology enrichment analysis revealed that differentially expressed genes were enriched for immune-related molecules and processes, such as cuticle development, prostaglandin, and defense response processes. Our findings provide a suite of immunologically relevant genes and suggest the presence of a rapidly upregulated immune response involving the cuticle in . Studies involving gene expression responses to pathogen exposure shine a light on the processes occurring during the course of infection. By leveraging knowledge on the genetic basis for immunity, immune mechanisms can be more thoroughly understood to refine our understanding of disease spread within invertebrate populations.
PubMed: 37529587
DOI: 10.1002/ece3.10354 -
Foods (Basel, Switzerland) Nov 2023This study identified and tested fruit-isolated yeasts against three major postharvest citrus pathogens, namely, , , and , and further evaluated the impact of FeCl on...
This study identified and tested fruit-isolated yeasts against three major postharvest citrus pathogens, namely, , , and , and further evaluated the impact of FeCl on the biocontrol efficiency of pulcherrimin-producing strains. Based on the characterization of the pigmented halo surrounding the colonies and the analysis of the D1/D2 domain of 26S rDNA, a total of 46 sp. were screened and identified. All 46 strains significantly inhibited the hyphal growth of , , and , and effectively controlled the development of green mold, blue mold and sour rot of citrus fruit. The introduction of exogenous FeCl at certain concentrations did not significantly impact the pulcherriminic acid (PA) production of pigmented strains, but notably diminished the size of pigmented zones and the biocontrol efficacy against the three pathogens. Iron deficiency sensitivity experiments revealed that and exhibited higher sensitivity compared to , indicating that iron dependence varied among the three pathogens. These results suggested that strains, capable of producing high yields of PA, possessed great potential for use as biocontrol agents against postharvest citrus diseases. The biocontrol efficacy of these yeasts is mainly attributed to their ability to competitively deplete iron ions in a shared environment, with the magnitude of their pigmented halo directly correlating to their antagonistic capability. It is worth noting that the level of sensitivity of pathogens to iron deficiency might also affect the biocontrol effect of pulcherrimin-producing .
PubMed: 38231683
DOI: 10.3390/foods12234249 -
Food Research International (Ottawa,... Dec 2023Microbial diseases are of major concern in vitiviniculture as they cause grape losses and wine alterations, but the prevention with chemical substances represents a risk...
Microbial diseases are of major concern in vitiviniculture as they cause grape losses and wine alterations, but the prevention with chemical substances represents a risk to human health and agricultural ecosystem. A promising alternative is the biocontrol and bioprotection activity of non-Saccharomyces yeasts, such as Metschnikowia pulcherrima, which also presents positive oenological traits when used in multistarter fermentations. The aim of this study was to assess the impact of a selected M. pulcherrima strain in the post-harvest withering and vinification of Garganega grapes to produce the sweet 'passito' wine Recioto di Gambellara DOCG (Italy). M. pulcherrima was firstly inoculated on grape at the beginning of the withering process, and afterwards in must for multistarter sequential microfermentation trials with Saccharomyces cerevisiae. Microbiological, chemical, and sensory analyses were carried out to monitor the vinification of treated and control grapes. Grape bunches during withering were a suitable environment for the colonization by M. pulcherrima, which effectively prevented growth of molds. Differences in grape must composition were observed, and the diverse inoculation strategies caused noticeable variations of fermentation kinetics, main oenological parameters, wine aroma profile, and sensory perception. M. pulcherrima proved effective to protect grapes against fungal infections during withering and contribute to alcoholic fermentation generating wine with distinguished aromatic characteristics.
Topics: Humans; Wine; Odorants; Ecosystem; Vitis; Saccharomyces cerevisiae
PubMed: 37986429
DOI: 10.1016/j.foodres.2023.113550