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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 -
International Journal of Food... Nov 2023Bioprotection by yeast addition is increasingly used in oenology as an alternative to sulfur dioxide (SO). Recent studies have also shown that it is likely to consume...
Bioprotection by yeast addition is increasingly used in oenology as an alternative to sulfur dioxide (SO). Recent studies have also shown that it is likely to consume dissolved O. This ability could limit O for other microorganisms and the early oxidation of the grape must. However, the ability of yeasts to consume O in a context of bioprotection was poorly studied so far considering the high genetic diversity of non-Saccharomyces. The first aim of the present study was to perform an O consumption rate (OCR) screening of strains from a large multi species collection found in oenology. The results demonstrate significant inter and intra species diversity with regard to O consumption. In the must M. pulcherrima consumes O faster than Saccharomyces cerevisiae and then other studied non-Saccharomyces species. The O consumption was also evaluate in the context of a yeast mix used as industrial bioprotection (Metschnikowia pulcherrima and Torulaspora delbrueckii) in red must. These non-Saccharomyces yeasts were then showed to limit the growth of acetic acid bacteria, with a bioprotective effect comparable to that of the addition of sulfur dioxide. Laboratory experiment confirmed the negative impact of the non-Saccharomyces yeasts on Gluconobacter oxydans that may be related to O consumption. This study sheds new lights on the use of bioprotection as an alternative to SO and suggest the possibility to use O consumption measurements as a new criteria for non-Saccharomyces strain selection in a context of bioprotection application for the wine industry.
Topics: Saccharomyces cerevisiae; Acetic Acid; Sulfur Dioxide; Wine; Fermentation; Yeasts; Vitis; Bacteria
PubMed: 37506548
DOI: 10.1016/j.ijfoodmicro.2023.110338 -
FEMS Microbiology Ecology Jul 2023Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi... (Review)
Review
Bee-fungus associations are common, and while most studies focus on entomopathogens, emerging evidence suggests that bees associate with a variety of symbiotic fungi that can influence bee behavior and health. Here, we review nonpathogenic fungal taxa associated with different bee species and bee-related habitats. We synthesize results of studies examining fungal effects on bee behavior, development, survival, and fitness. We find that fungal communities differ across habitats, with some groups restricted mostly to flowers (Metschnikowia), while others are present almost exclusively in stored provisions (Zygosaccharomyces). Starmerella yeasts are found in multiple habitats in association with many bee species. Bee species differ widely in the abundance and identity of fungi hosted. Functional studies suggest that yeasts affect bee foraging, development, and pathogen interactions, though few bee and fungal taxa have been examined in this context. Rarely, fungi are obligately beneficial symbionts of bees, whereas most are facultative bee associates with unknown or ecologically contextual effects. Fungicides can reduce fungal abundance and alter fungal communities associated with bees, potentially disrupting bee-fungi associations. We recommend that future study focus on fungi associated with non-honeybee species and examine multiple bee life stages to document fungal composition, abundance, and mechanistic effects on bees.
Topics: Bees; Animals; Fungicides, Industrial; Ecosystem; Mycobiome; Porifera; Metschnikowia; Fungi
PubMed: 37422442
DOI: 10.1093/femsec/fiad077 -
Food Research International (Ottawa,... Aug 2023In this study we investigated the yeast population present on partially dehydrated Nebbiolo grapes destined for 'Sforzato di Valtellina', with the aim to select...
In this study we investigated the yeast population present on partially dehydrated Nebbiolo grapes destined for 'Sforzato di Valtellina', with the aim to select indigenous starters suitable for the production of this wine. Yeasts were enumerated, isolated, and identified by molecular methods (5.8S-ITS-RFLP and D1/D2 domain sequencing). A genetic, physiological (ethanol and sulphur dioxide tolerance, potentially useful enzymatic activities, hydrogen sulphide production, adhesive properties, and killer activity) and oenological (laboratory pure micro-fermentations) characterization was also carried out. Based on relevant physiological features, seven non-Saccharomyces strains were chosen for laboratory-scale fermentations, either in pure or in mixed-culture (simultaneous and sequential inoculum) with a commercial Saccharomyces cerevisiae strain. Finally, the best couples and inoculation strategy were further tested in mixed fermentations in winery. In both laboratory and winery, microbiological and chemical analyses were conducted during fermentation. The most abundant species on grapes were Hanseniaspora uvarum (27.4 % of the isolates), followed by Metschnikowia spp. (21.0 %) and Starmerella bacillaris (12.9 %). Technological characterization highlighted several inter- and intra-species differences. The best oenological aptitude was highlighted for species Starm. bacillaris, Metschnikowia spp., Pichia kluyveri and Zygosaccharomyces bailli. The best fermentation performances in laboratory-scale fermentations were found for Starm. bacillaris and P. kluyveri, due to their ability to reduce ethanol (-0.34 % v/v) and enhance glycerol production (+0.46 g/L). This behavior was further confirmed in winery. Results of this study contribute to the knowledge of yeast communities associated with a specific environment, like those of Valtellina wine region.
Topics: Saccharomyces cerevisiae; Vitis; Wine; Fermentation; Yeast, Dried; Metschnikowia
PubMed: 37316074
DOI: 10.1016/j.foodres.2023.113005 -
Food Microbiology Sep 2023While sequentially inoculating non-Saccharomyces yeasts with Saccharomyces cerevisiae can lower the alcohol contents of wine, the abilities of these yeasts to...
While sequentially inoculating non-Saccharomyces yeasts with Saccharomyces cerevisiae can lower the alcohol contents of wine, the abilities of these yeasts to utilize/produce ethanol or generate other byproducts remained unclear. Metschnikowia pulcherrima or Meyerozyma guilliermondii were inoculated into media with or without S. cerevisiae to assess byproduct formation. Both species metabolized ethanol in a yeast-nitrogen-base medium but produced the alcohol in a synthetic grape juice medium. In fact, Mt. pulcherrima and My. guilliermondii generated less ethanol per gram of metabolized sugar (0.372 and 0.301 g/g, respectively) compared to S. cerevisiae (0.422 g/g). Sequentially inoculating each non-Saccharomyces species with S. cerevisiae into grape juice media achieved up to 3.0% v/v alcohol reduction compared to S. cerevisiae alone while producing variable glycerol, succinic acid, and acetic acid concentrations. However, neither non-Saccharomyces yeasts released appreciable CO under fermentative conditions regardless of incubation temperature. Despite equivalent peak populations, S. cerevisiae produced more biomass (2.98 g/L) than the non-Saccharomyces yeasts while sequential inoculations yielded higher biomass with Mt. pulcherrima (3.97 g/L) but not My. guilliermondii (3.03 g/L). To reduce ethanol concentrations, these non-Saccharomyces species may metabolize ethanol and/or produce less from metabolized sugars compared to S. cerevisiae but also divert carbon towards glycerol, succinic acid, and/or biomass.
Topics: Saccharomyces cerevisiae; Fermentation; Glycerol; Carbon; Succinic Acid; Metschnikowia; Ethanol; Wine; Vitis
PubMed: 37290869
DOI: 10.1016/j.fm.2023.104308 -
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 -
Brazilian Journal of Microbiology :... Sep 2023We evaluated the diversity and enzymatic activities of culturable fungi recovered from cotton baits submerged for 2 years in Hennequin Lake, King George Island, and...
We evaluated the diversity and enzymatic activities of culturable fungi recovered from cotton baits submerged for 2 years in Hennequin Lake, King George Island, and from benthic biofilms in Kroner Lake, Deception Island, South Shetland Islands, maritime Antarctica. A total of 154 fungal isolates were obtained, representing in rank abundance the phyla Ascomycota, Basidiomycota and Mortierellomycota. Thelebolus globosus, Goffeauzyma sp., Pseudogymnoascus verrucosus and Metschnikowia australis were the most abundant taxa. The fungal community obtained from the biofilm was more diverse and richer than that recovered from the cotton baits. However, diversity indices suggested that the lakes may harbour further fungal diversity. The capabilities of all cultured fungi to produce the extracellular enzymes cellulase, protease, lipase, agarase, carrageenase, invertase, amylase, esterase, pectinase, inulinase and gelatinase at low temperature were evaluated. All enzymes were detected, but the most widely produced were protease and pectinase. The best enzymatic indices were obtained from Holtermanniella wattica (for invertase, esterase), Goffeauzyma sp. (amylase), Metschnikowia australis (protease), Mrakia blollopis (cellulase, pectinase), Pseudogymnoascus verrucosus (agarase, carrageenase) and Leucosporidium fragarium (inulinase). The detection of multiple enzymes reinforces the ecological role of fungi in nutrient cycling in Antarctic lakes, making nutrients available to the complex aquatic food web. Furthermore, such low-temperature-active enzymes may find application in different biotechnological processes, such as in the textile, pharmaceutical, food, detergent and paper industries, as well as environmental application in pollutant bioremediation processes.
Topics: Temperature; Lakes; Antarctic Regions; beta-Fructofuranosidase; Polygalacturonase; Lipase; Peptide Hydrolases; Amylases; Cellulases; Fungi
PubMed: 36274089
DOI: 10.1007/s42770-022-00834-x