The Experts below are selected from a list of 393 Experts worldwide ranked by ideXlab platform
Keith A Seifert - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE A Taxonomic Revision of theWallemia sebi Species Complex
2016Co-Authors: Saso Jancic, Hai D T Nguyen, Polona Zalar, Keith A Seifert, Jens C. Frisvad, Hans-josef Schroers, Nina Gunde-cimermanAbstract:Wallemia sebi is a xerophilic food- and air-borne fungus. The name has been used for strains that prevail in cold, temperate and tropical climates. In this study, multi-locus phy-logenetic analyses, using the internal transcribed spacer (ITS) regions, DNA replication li-censing factor (MCM7), pre-rRNA processing protein (TSR1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and a new marker 3´-phosphoadenosine-5´-phosphatase (HAL2), confirmed the previous hypothesis that W. sebi presents a complex of at least four species. Here, we confirm and apply the phylo-genetic analyses based species hypotheses from a companion study to guide phenotypic assessment ofW. sebi like strains from a wide range of substrates, climates and conti-nents allowed the recognition ofW. sebi sensu stricto and three new species described as W.mellicola,W. Canadensis, andW. tropicalis. The species differ in their conidial size, xerotolerance, halotolerance, chaotolerance, growth temperature regimes, extracellular enzyme activity profiles, and secondary metabolite patterns. A key to all currently accept-edWallemia species is provided that allow their identification on the basis of physiological, micromorphological and culture characters
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application of the phylogenetic species concept to Wallemia sebi from house dust and indoor air revealed by multi locus genealogical concordance
PLOS ONE, 2015Co-Authors: Hai D T Nguyen, Nina Gundecimerman, Saso Jancic, M Meijer, Joey B Tanney, Polona Zalar, Keith A SeifertAbstract:A worldwide survey of Wallemia occurring in house dust and indoor air was conducted. The isolated strains were identified as W. sebi and W. muriae. Previous studies suggested that the W. sebi phylogenetic clade contained cryptic species but conclusive evidence was lacking because only the internal transcribed spacer (ITS) marker was analyzed. The ITS and four protein-coding genes (MCM7, RPB1, RPB2, and TSR1) were sequenced for 85 isolates. Based on an initial neighbor joining analysis of the concatenated genes, W. muriae remained monophyletic but four clades were found in W. sebi, which we designated as W. sebi clades 1, 2, 3, and 4. We hypothesized that these clades represent distinct phylogenetic species within the Wallemia sebi species complex (WSSC). We then conducted multiple phylogenetic analyses and demonstrated genealogical concordance, which supports the existence of four phylogenetic species within the WSSC. Geographically, W. muriae was only found in Europe, W. sebi clade 3 was only found in Canada, W. sebi clade 4 was found in subtropical regions, while W. sebi clade 1 and 2 were found worldwide. Haplotype analysis showed that W. sebi clades 1 and 2 had multiple haplotypes while W. sebi clades 3 and 4 had one haplotype and may have been under sampled. We describe W. sebi clades 2, 3, and 4 as new species in a companion study.
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A Taxonomic Revision of the Wallemia sebi Species Complex
2015Co-Authors: Saso Jancic, Hai D T Nguyen, Polona Zalar, Keith A Seifert, Jens C. Frisvad, Hans-josef Schroers, Nina Gunde-cimermanAbstract:Wallemia sebi is a xerophilic food- and air-borne fungus. The name has been used for strains that prevail in cold, temperate and tropical climates. In this study, multi-locus phylogenetic analyses, using the internal transcribed spacer (ITS) regions, DNA replication licensing factor (MCM7), pre-rRNA processing protein (TSR1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and a new marker 3´-phosphoadenosine-5´-phosphatase (HAL2), confirmed the previous hypothesis that W. sebi presents a complex of at least four species. Here, we confirm and apply the phylogenetic analyses based species hypotheses from a companion study to guide phenotypic assessment of W. sebi like strains from a wide range of substrates, climates and continents allowed the recognition of W. sebi sensu stricto and three new species described as W. mellicola, W. Canadensis, and W. tropicalis. The species differ in their conidial size, xerotolerance, halotolerance, chaotolerance, growth temperature regimes, extracellular enzyme activity profiles, and secondary metabolite patterns. A key to all currently accepted Wallemia species is provided that allow their identification on the basis of physiological, micromorphological and culture characters.
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Application of the Phylogenetic Species Concept to Wallemia sebi from House Dust and Indoor Air Revealed by Multi-Locus Genealogical Concordance
2015Co-Authors: Hai D T Nguyen, Saso Jancic, M Meijer, Joey B Tanney, Polona Zalar, Nina Gunde-cimerman, Keith A SeifertAbstract:A worldwide survey of Wallemia occurring in house dust and indoor air was conducted. The isolated strains were identified as W. sebi and W. muriae. Previous studies suggested that the W. sebi phylogenetic clade contained cryptic species but conclusive evidence was lacking because only the internal transcribed spacer (ITS) marker was analyzed. The ITS and four protein-coding genes (MCM7, RPB1, RPB2, and TSR1) were sequenced for 85 isolates. Based on an initial neighbor joining analysis of the concatenated genes, W. muriae remained monophyletic but four clades were found in W. sebi, which we designated as W. sebi clades 1, 2, 3, and 4. We hypothesized that these clades represent distinct phylogenetic species within the Wallemia sebi species complex (WSSC). We then conducted multiple phylogenetic analyses and demonstrated genealogical concordance, which supports the existence of four phylogenetic species within the WSSC. Geographically, W. muriae was only found in Europe, W. sebi clade 3 was only found in Canada, W. sebi clade 4 was found in subtropical regions, while W. sebi clade 1 and 2 were found worldwide. Haplotype analysis showed that W. sebi clades 1 and 2 had multiple haplotypes while W. sebi clades 3 and 4 had one haplotype and may have been under sampled. We describe W. sebi clades 2, 3, and 4 as new species in a companion study.
Nina Gunde-cimerman - One of the best experts on this subject based on the ideXlab platform.
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Overview of Oxidative Stress Response Genes in Selected Halophilic Fungi.
Genes, 2018Co-Authors: Cene Gostinčar, Nina Gunde-cimermanAbstract:Exposure of microorganisms to stress, including to high concentrations of salt, can lead to increased production of reactive oxygen species in the cell. To limit the resulting damage, cells have evolved a variety of antioxidant defenses. The role of these defenses in halotolerance has been proposed before. Whole genome sequencing for some of the most halotolerant and halophilic fungal species has enabled us to investigate the possible links between oxidative and salt stress tolerance on the genomic level. We identified genes involved in oxidative stress response in the halophilic basidiomycete Wallemia ichthyophaga, and halotolerant ascomycetous black yeasts Hortaea werneckii and Aureobasidium pullulans, and compared them to genes from 16 other fungi, both asco- and basidiomycetes. According to our results, W. ichthyophaga can survive salinities detrimental to most other organisms with only a moderate number of oxidative stress response genes. In other investigated species, however, the maximum tolerated salinity correlated with the number of genes encoding three major enzymes of the cellular oxidative stress response: superoxide dismutases, catalases, and peroxiredoxins. This observation supports the hypothetical link between the antioxidant capacity of cells and their halotolerance.
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The Genus Wallemia—From Contamination of Food to Health Threat
MDPI AG, 2018Co-Authors: Janja Zajc, Nina Gunde-cimermanAbstract:The fungal genus Wallemia of the order Wallemiales (Wallemiomycotina, Basidiomycota) comprises the most xerotolerant, xerophilic and also halophilic species worldwide. Wallemia spp. are found in various osmotically challenged environments, such as dry, salted, or highly sugared foods, dry feed, hypersaline waters of solar salterns, salt crystals, indoor and outdoor air, and agriculture aerosols. Recently, eight species were recognized for the genus Wallemia, among which four are commonly associated with foods: W. sebi, W. mellicola, W. muriae and W. ichthyophaga. To date, only strains of W. sebi, W. mellicola and W. muriae have been reported to be related to human health problems, as either allergological conditions (e.g., farmer’s lung disease) or rare subcutaneous/cutaneous infections. Therefore, this allergological and infective potential, together with the toxins that the majority of Wallemia spp. produce even under saline conditions, defines these fungi as filamentous food-borne pathogenic fungi
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RESEARCH ARTICLE A Taxonomic Revision of theWallemia sebi Species Complex
2016Co-Authors: Saso Jancic, Hai D T Nguyen, Polona Zalar, Keith A Seifert, Jens C. Frisvad, Hans-josef Schroers, Nina Gunde-cimermanAbstract:Wallemia sebi is a xerophilic food- and air-borne fungus. The name has been used for strains that prevail in cold, temperate and tropical climates. In this study, multi-locus phy-logenetic analyses, using the internal transcribed spacer (ITS) regions, DNA replication li-censing factor (MCM7), pre-rRNA processing protein (TSR1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and a new marker 3´-phosphoadenosine-5´-phosphatase (HAL2), confirmed the previous hypothesis that W. sebi presents a complex of at least four species. Here, we confirm and apply the phylo-genetic analyses based species hypotheses from a companion study to guide phenotypic assessment ofW. sebi like strains from a wide range of substrates, climates and conti-nents allowed the recognition ofW. sebi sensu stricto and three new species described as W.mellicola,W. Canadensis, andW. tropicalis. The species differ in their conidial size, xerotolerance, halotolerance, chaotolerance, growth temperature regimes, extracellular enzyme activity profiles, and secondary metabolite patterns. A key to all currently accept-edWallemia species is provided that allow their identification on the basis of physiological, micromorphological and culture characters
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Secondary metabolites reported from the Wallemia.
2016Co-Authors: Saso Jancic, Cene Gostinčar, Jens C. Frisvad, Dragi Kocev, Sašo Džeroski, Nina Gunde-cimermanAbstract:Secondary metabolites reported from the Wallemia.
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Production of Secondary Metabolites in Extreme Environments: Food- and Airborne Wallemia spp. Produce Toxic Metabolites at Hypersaline Conditions
2016Co-Authors: Saso Jancic, Cene Gostinčar, Jens C. Frisvad, Dragi Kocev, Sašo Džeroski, Nina Gunde-cimermanAbstract:The food- and airborne fungal genus Wallemia comprises seven xerophilic and halophilic species: W. sebi, W. mellicola, W. canadensis, W. tropicalis, W. muriae, W. hederae and W. ichthyophaga. All listed species are adapted to low water activity and can contaminate food preserved with high amounts of salt or sugar. In relation to food safety, the effect of high salt and sugar concentrations on the production of secondary metabolites by this toxigenic fungus was investigated. The secondary metabolite profiles of 30 strains of the listed species were examined using general growth media, known to support the production of secondary metabolites, supplemented with different concentrations of NaCl, glucose and MgCl2. In more than two hundred extracts approximately one hundred different compounds were detected using high-performance liquid chromatography-diode array detection (HPLC-DAD). Although the genome data analysis of W. mellicola (previously W. sebi sensu lato) and W. ichthyophaga revealed a low number of secondary metabolites clusters, a substantial number of secondary metabolites were detected at different conditions. Machine learning analysis of the obtained dataset showed that NaCl has higher influence on the production of secondary metabolites than other tested solutes. Mass spectrometric analysis of selected extracts revealed that NaCl in the medium affects the production of some compounds with substantial biological activities (wallimidione, walleminol, walleminone, UCA 1064-A and UCA 1064-B). In particular an increase in NaCl concentration from 5% to 15% in the growth media increased the production of the toxic metabolites wallimidione, walleminol and walleminone.
Jie Tang - One of the best experts on this subject based on the ideXlab platform.
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Expansion of commensal fungus Wallemia mellicola in the gastrointestinal mycobiota enhances the severity of allergic airway disease in mice.
PLOS Pathogens, 2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David UnderhillAbstract:The gastrointestinal microbiota influences immune function throughout the body. The gut-lung axis refers to the concept that alterations of gut commensal microorganisms can have a distant effect on immune function in the lung. Overgrowth of intestinal Candida albicans has been previously observed to exacerbate allergic airways disease in mice, but whether subtler changes in intestinal fungal microbiota can affect allergic airways disease is less clear. In this study we have investigated the effects of the population expansion of commensal fungus Wallemia mellicola without overgrowth of the total fungal community. Wallemia spp. are commonly found as a minor component of the commensal gastrointestinal mycobiota in both humans and mice. Mice with an unaltered gut microbiota community resist population expansion when gavaged with W. mellicola; however, transient antibiotic depletion of gut microbiota creates a window of opportunity for expansion of W. mellicola following delivery of live spores to the gastrointestinal tract. This phenomenon is not universal as other commensal fungi (Aspergillus amstelodami, Epicoccum nigrum) do not expand when delivered to mice with antibiotic-depleted microbiota. Mice with Wallemia-expanded gut mycobiota experienced altered pulmonary immune responses to inhaled aeroallergens. Specifically, after induction of allergic airways disease with intratracheal house dust mite (HDM) antigen, mice demonstrated enhanced eosinophilic airway infiltration, airway hyperresponsiveness (AHR) to methacholine challenge, goblet cell hyperplasia, elevated bronchoalveolar lavage IL-5, and enhanced serum HDM IgG1. This phenomenon occurred with no detectable Wallemia in the lung. Targeted amplicon sequencing analysis of the gastrointestinal mycobiota revealed that expansion of W. mellicola in the gut was associated with additional alterations of bacterial and fungal commensal communities. We therefore colonized fungus-free Altered Schaedler Flora (ASF) mice with W. mellicola. ASF mice colonized with W. mellicola experienced enhanced severity of allergic airways disease compared to fungus-free control ASF mice without changes in bacterial community composition.
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Commensal fungi examined in this manuscript are also detectable in the human gastrointestinal system.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fungal DNA content per stool weight from healthy human volunteers with no recent antibiotic use. Levels of the indicated fungi were assessed by quantitative PCR of rDNA (by comparison to standard curves generated from control samples with defined fungal DNA content). (B) Wallemia abundance among the Wallemia-colonized humans is similar to unmodified SPF mice from our facility but less than mice with Wallemia-enhanced colonization. (C) Total fungal DNA burden in healthy human volunteers by rtPCR per stool weight. Red dots indicate human samples with detectable Wallemia. Wallemia-colonized humans do not generally have higher total fungal burden in this cohort compared to individuals without Wallemia colonization.
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Characteristics of Wallemia mellicola expanded colonization.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) W. mellicola population expansion occurs predominantly in the cecum and colon with no detectable Wallemia DNA in extraintestinal organs. The indicated tissue samples collected from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 5 per group) were analyzed for Wallemia DNA by quantitative PCR. (B) Fungal communities were assessed by ITS1 sequencing. Fecal samples from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 4 per group) were analyzed, and pie charts illustrate genera distributions. (C) Unlike antibiotic-associated Candida albicans overgrowth, total fungal burden in Wallemia-expanded mice does not increase compared to SPF mice. Fecal samples from the indicated sources (mice at day 14, n = 4 per group) were assessed for total fungal content by quantitative PCR. Statistical comparisons are between indicated bar and SPF mouse group. (D-E) W. mellicola does not induced pathology. Weight was monitored in control and W. mellicola-colonized mice (D). Histology of colons of Wallemia-colonized animals examined by H&E staining (400X) do not show obvious signs of inflammatory disease. Figures are representative examples of experiments independently performed at least three times. *, p < .05; **, p < .01; ***, p
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Wallemia expansion in specific pathogen free (SPF) mice alters commensal bacterial and fungal communities.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A-B) Bacterial communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing bacterial communities by 16S sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. Significant differences are highlighted on the cladogram (C-D) Fungal communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing fungal communities by ITS1 sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. (E) Box plots show relative abundance’s median and the first and third quartiles for the indicated fungi. Whiskers extend no further than 1.5 times IQR from the hinge, and p value determined as unpaired two-tailed Student’s T-test.
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Enhanced colonization with Wallemia mellicola.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fluconazole in the drinking water alters but does not uniformly deplete gastrointestinal commensal fungal populations. Levels of the indicated organisms in fecal samples from specific pathogen free (SPF) mice treated for 21 days with fluconazole were measured by quantitative PCR. (B) Graphical depiction of fungal colonization protocol utilized in experiments in panel D. (C) Antibiotic (cefoperazone) treatment in the drinking water profoundly and transiently depletes total stool bacterial content (measured by quantitative 16S PCR) in control animals over the course of an experiment. Antibiotic water in this experiment administered day 3–12. Statistical comparisons are between indicated bar and day #1 samples. (D) Mice with antibiotic-depleted gastrointestinal flora are vulnerable to Wallemia mellicola expansion. Mice were exposed by gastric gavage to the indicated fungi (5 x 106 live organisms), and stool levels were assessed by quantitative PCR at the indicated times. Figures are a representative example of experiment that was independently performed three times with 5 animals per group. *, p < .05; **, p < .01; ***, p
Matthew Gargus - One of the best experts on this subject based on the ideXlab platform.
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Expansion of commensal fungus Wallemia mellicola in the gastrointestinal mycobiota enhances the severity of allergic airway disease in mice.
PLOS Pathogens, 2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David UnderhillAbstract:The gastrointestinal microbiota influences immune function throughout the body. The gut-lung axis refers to the concept that alterations of gut commensal microorganisms can have a distant effect on immune function in the lung. Overgrowth of intestinal Candida albicans has been previously observed to exacerbate allergic airways disease in mice, but whether subtler changes in intestinal fungal microbiota can affect allergic airways disease is less clear. In this study we have investigated the effects of the population expansion of commensal fungus Wallemia mellicola without overgrowth of the total fungal community. Wallemia spp. are commonly found as a minor component of the commensal gastrointestinal mycobiota in both humans and mice. Mice with an unaltered gut microbiota community resist population expansion when gavaged with W. mellicola; however, transient antibiotic depletion of gut microbiota creates a window of opportunity for expansion of W. mellicola following delivery of live spores to the gastrointestinal tract. This phenomenon is not universal as other commensal fungi (Aspergillus amstelodami, Epicoccum nigrum) do not expand when delivered to mice with antibiotic-depleted microbiota. Mice with Wallemia-expanded gut mycobiota experienced altered pulmonary immune responses to inhaled aeroallergens. Specifically, after induction of allergic airways disease with intratracheal house dust mite (HDM) antigen, mice demonstrated enhanced eosinophilic airway infiltration, airway hyperresponsiveness (AHR) to methacholine challenge, goblet cell hyperplasia, elevated bronchoalveolar lavage IL-5, and enhanced serum HDM IgG1. This phenomenon occurred with no detectable Wallemia in the lung. Targeted amplicon sequencing analysis of the gastrointestinal mycobiota revealed that expansion of W. mellicola in the gut was associated with additional alterations of bacterial and fungal commensal communities. We therefore colonized fungus-free Altered Schaedler Flora (ASF) mice with W. mellicola. ASF mice colonized with W. mellicola experienced enhanced severity of allergic airways disease compared to fungus-free control ASF mice without changes in bacterial community composition.
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Commensal fungi examined in this manuscript are also detectable in the human gastrointestinal system.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fungal DNA content per stool weight from healthy human volunteers with no recent antibiotic use. Levels of the indicated fungi were assessed by quantitative PCR of rDNA (by comparison to standard curves generated from control samples with defined fungal DNA content). (B) Wallemia abundance among the Wallemia-colonized humans is similar to unmodified SPF mice from our facility but less than mice with Wallemia-enhanced colonization. (C) Total fungal DNA burden in healthy human volunteers by rtPCR per stool weight. Red dots indicate human samples with detectable Wallemia. Wallemia-colonized humans do not generally have higher total fungal burden in this cohort compared to individuals without Wallemia colonization.
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Characteristics of Wallemia mellicola expanded colonization.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) W. mellicola population expansion occurs predominantly in the cecum and colon with no detectable Wallemia DNA in extraintestinal organs. The indicated tissue samples collected from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 5 per group) were analyzed for Wallemia DNA by quantitative PCR. (B) Fungal communities were assessed by ITS1 sequencing. Fecal samples from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 4 per group) were analyzed, and pie charts illustrate genera distributions. (C) Unlike antibiotic-associated Candida albicans overgrowth, total fungal burden in Wallemia-expanded mice does not increase compared to SPF mice. Fecal samples from the indicated sources (mice at day 14, n = 4 per group) were assessed for total fungal content by quantitative PCR. Statistical comparisons are between indicated bar and SPF mouse group. (D-E) W. mellicola does not induced pathology. Weight was monitored in control and W. mellicola-colonized mice (D). Histology of colons of Wallemia-colonized animals examined by H&E staining (400X) do not show obvious signs of inflammatory disease. Figures are representative examples of experiments independently performed at least three times. *, p < .05; **, p < .01; ***, p
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Wallemia expansion in specific pathogen free (SPF) mice alters commensal bacterial and fungal communities.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A-B) Bacterial communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing bacterial communities by 16S sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. Significant differences are highlighted on the cladogram (C-D) Fungal communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing fungal communities by ITS1 sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. (E) Box plots show relative abundance’s median and the first and third quartiles for the indicated fungi. Whiskers extend no further than 1.5 times IQR from the hinge, and p value determined as unpaired two-tailed Student’s T-test.
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Enhanced colonization with Wallemia mellicola.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fluconazole in the drinking water alters but does not uniformly deplete gastrointestinal commensal fungal populations. Levels of the indicated organisms in fecal samples from specific pathogen free (SPF) mice treated for 21 days with fluconazole were measured by quantitative PCR. (B) Graphical depiction of fungal colonization protocol utilized in experiments in panel D. (C) Antibiotic (cefoperazone) treatment in the drinking water profoundly and transiently depletes total stool bacterial content (measured by quantitative 16S PCR) in control animals over the course of an experiment. Antibiotic water in this experiment administered day 3–12. Statistical comparisons are between indicated bar and day #1 samples. (D) Mice with antibiotic-depleted gastrointestinal flora are vulnerable to Wallemia mellicola expansion. Mice were exposed by gastric gavage to the indicated fungi (5 x 106 live organisms), and stool levels were assessed by quantitative PCR at the indicated times. Figures are a representative example of experiment that was independently performed three times with 5 animals per group. *, p < .05; **, p < .01; ***, p
Jose J. Limon - One of the best experts on this subject based on the ideXlab platform.
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Expansion of commensal fungus Wallemia mellicola in the gastrointestinal mycobiota enhances the severity of allergic airway disease in mice.
PLOS Pathogens, 2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David UnderhillAbstract:The gastrointestinal microbiota influences immune function throughout the body. The gut-lung axis refers to the concept that alterations of gut commensal microorganisms can have a distant effect on immune function in the lung. Overgrowth of intestinal Candida albicans has been previously observed to exacerbate allergic airways disease in mice, but whether subtler changes in intestinal fungal microbiota can affect allergic airways disease is less clear. In this study we have investigated the effects of the population expansion of commensal fungus Wallemia mellicola without overgrowth of the total fungal community. Wallemia spp. are commonly found as a minor component of the commensal gastrointestinal mycobiota in both humans and mice. Mice with an unaltered gut microbiota community resist population expansion when gavaged with W. mellicola; however, transient antibiotic depletion of gut microbiota creates a window of opportunity for expansion of W. mellicola following delivery of live spores to the gastrointestinal tract. This phenomenon is not universal as other commensal fungi (Aspergillus amstelodami, Epicoccum nigrum) do not expand when delivered to mice with antibiotic-depleted microbiota. Mice with Wallemia-expanded gut mycobiota experienced altered pulmonary immune responses to inhaled aeroallergens. Specifically, after induction of allergic airways disease with intratracheal house dust mite (HDM) antigen, mice demonstrated enhanced eosinophilic airway infiltration, airway hyperresponsiveness (AHR) to methacholine challenge, goblet cell hyperplasia, elevated bronchoalveolar lavage IL-5, and enhanced serum HDM IgG1. This phenomenon occurred with no detectable Wallemia in the lung. Targeted amplicon sequencing analysis of the gastrointestinal mycobiota revealed that expansion of W. mellicola in the gut was associated with additional alterations of bacterial and fungal commensal communities. We therefore colonized fungus-free Altered Schaedler Flora (ASF) mice with W. mellicola. ASF mice colonized with W. mellicola experienced enhanced severity of allergic airways disease compared to fungus-free control ASF mice without changes in bacterial community composition.
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Commensal fungi examined in this manuscript are also detectable in the human gastrointestinal system.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fungal DNA content per stool weight from healthy human volunteers with no recent antibiotic use. Levels of the indicated fungi were assessed by quantitative PCR of rDNA (by comparison to standard curves generated from control samples with defined fungal DNA content). (B) Wallemia abundance among the Wallemia-colonized humans is similar to unmodified SPF mice from our facility but less than mice with Wallemia-enhanced colonization. (C) Total fungal DNA burden in healthy human volunteers by rtPCR per stool weight. Red dots indicate human samples with detectable Wallemia. Wallemia-colonized humans do not generally have higher total fungal burden in this cohort compared to individuals without Wallemia colonization.
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Characteristics of Wallemia mellicola expanded colonization.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) W. mellicola population expansion occurs predominantly in the cecum and colon with no detectable Wallemia DNA in extraintestinal organs. The indicated tissue samples collected from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 5 per group) were analyzed for Wallemia DNA by quantitative PCR. (B) Fungal communities were assessed by ITS1 sequencing. Fecal samples from antibiotic-only control or W. mellicola-colonized mice (at day 14, n = 4 per group) were analyzed, and pie charts illustrate genera distributions. (C) Unlike antibiotic-associated Candida albicans overgrowth, total fungal burden in Wallemia-expanded mice does not increase compared to SPF mice. Fecal samples from the indicated sources (mice at day 14, n = 4 per group) were assessed for total fungal content by quantitative PCR. Statistical comparisons are between indicated bar and SPF mouse group. (D-E) W. mellicola does not induced pathology. Weight was monitored in control and W. mellicola-colonized mice (D). Histology of colons of Wallemia-colonized animals examined by H&E staining (400X) do not show obvious signs of inflammatory disease. Figures are representative examples of experiments independently performed at least three times. *, p < .05; **, p < .01; ***, p
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Wallemia expansion in specific pathogen free (SPF) mice alters commensal bacterial and fungal communities.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A-B) Bacterial communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing bacterial communities by 16S sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. Significant differences are highlighted on the cladogram (C-D) Fungal communities are altered by Wallemia expansion. Plots show principle coordinate analysis and LEfSe analysis (cladogram) comparing fungal communities by ITS1 sequencing in SPF mice 6 days after control or W. mellicola gavage as in Fig 1. (E) Box plots show relative abundance’s median and the first and third quartiles for the indicated fungi. Whiskers extend no further than 1.5 times IQR from the hinge, and p value determined as unpaired two-tailed Student’s T-test.
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Enhanced colonization with Wallemia mellicola.
2018Co-Authors: Joseph H. Skalski, Jose J. Limon, Purnima Sharma, Matthew Gargus, Timothy R. Crother, Ana Lucia Coelho, Cory M Hogaboam, Christopher Nguyen, Jie Tang, David M. UnderhillAbstract:(A) Fluconazole in the drinking water alters but does not uniformly deplete gastrointestinal commensal fungal populations. Levels of the indicated organisms in fecal samples from specific pathogen free (SPF) mice treated for 21 days with fluconazole were measured by quantitative PCR. (B) Graphical depiction of fungal colonization protocol utilized in experiments in panel D. (C) Antibiotic (cefoperazone) treatment in the drinking water profoundly and transiently depletes total stool bacterial content (measured by quantitative 16S PCR) in control animals over the course of an experiment. Antibiotic water in this experiment administered day 3–12. Statistical comparisons are between indicated bar and day #1 samples. (D) Mice with antibiotic-depleted gastrointestinal flora are vulnerable to Wallemia mellicola expansion. Mice were exposed by gastric gavage to the indicated fungi (5 x 106 live organisms), and stool levels were assessed by quantitative PCR at the indicated times. Figures are a representative example of experiment that was independently performed three times with 5 animals per group. *, p < .05; **, p < .01; ***, p
