Journal of Fungi

23 pages, 2831 KiB

Open AccessEditor’s ChoiceArticle

Exploring the Diversity of Fungal DyPs in Mangrove Soils to Produce and Characterize Novel Biocatalysts

by Amal Ben Ayed, Geoffroy Saint-Genis, Laurent Vallon, Dolores Linde, Annick Turbé-Doan, Mireille Haon, Marianne Daou, Emmanuel Bertrand, Craig B. Faulds, Giuliano Sciara, Martino Adamo, Roland Marmeisse, Sophie Comtet-Marre, Pierre Peyret, Danis Abrouk, Francisco J. Ruiz-Dueñas, Cyril Marchand, Mylène Hugoni, Patricia Luis, Tahar Mechichi and Eric Record Show full author list Hide full author list

J. Fungi 2021, 7(5), 321; https://doi.org/10.3390/jof7050321 - 21 Apr 2021

Cited by 6 | Viewed by 4564

Abstract

The functional diversity of the New Caledonian mangrove sediments was examined, observing the distribution of fungal dye-decolorizing peroxidases (DyPs), together with the complete biochemical characterization of the main DyP. Using a functional metabarcoding approach, the diversity of expressed genes encoding fungal DyPs was [...] Read more.

The functional diversity of the New Caledonian mangrove sediments was examined, observing the distribution of fungal dye-decolorizing peroxidases (DyPs), together with the complete biochemical characterization of the main DyP. Using a functional metabarcoding approach, the diversity of expressed genes encoding fungal DyPs was investigated in surface and deeper sediments, collected beneath either Avicennia marina or Rhizophora stylosa trees, during either the wet or the dry seasons. The highest DyP diversity was observed in surface sediments beneath the R. stylosa area during the wet season, and one particular operational functional unit (OFU1) was detected as the most abundant DyP isoform. This OFU was found in all sediment samples, representing 51–100% of the total DyP-encoding sequences in 70% of the samples. The complete cDNA sequence corresponding to this abundant DyP (OFU 1) was retrieved by gene capture, cloned, and heterologously expressed in Pichia pastoris. The recombinant enzyme, called DyP1, was purified and characterized, leading to the description of its physical–chemical properties, its ability to oxidize diverse phenolic substrates, and its potential to decolorize textile dyes; DyP1 was more active at low pH, though moderately stable over a wide pH range. The enzyme was very stable at temperatures up to 50 °C, retaining 60% activity after 180 min incubation. Its ability to decolorize industrial dyes was also tested on Reactive Blue 19, Acid Black, Disperse Blue 79, and Reactive Black 5. The effect of hydrogen peroxide and sea salt on DyP1 activity was studied and compared to what is reported for previously characterized enzymes from terrestrial and marine-derived fungi. Full article

(This article belongs to the Special Issue Exploiting Fungal Solutions for Today's Challenges)

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18 pages, 3439 KiB

Open AccessEditor’s ChoiceArticle

Terpenoid Biosynthesis Dominates among Secondary Metabolite Clusters in Mucoromycotina Genomes

by Grzegorz Koczyk, Julia Pawłowska and Anna Muszewska

J. Fungi 2021, 7(4), 285; https://doi.org/10.3390/jof7040285 - 9 Apr 2021

Cited by 13 | Viewed by 4358

Abstract

Early-diverging fungi harbour unprecedented diversity in terms of living forms, biological traits and genome architecture. Before the sequencing era, non-Dikarya fungi were considered unable to produce secondary metabolites (SM); however, this perspective is changing. The main classes of secondary metabolites in fungi include [...] Read more.

Early-diverging fungi harbour unprecedented diversity in terms of living forms, biological traits and genome architecture. Before the sequencing era, non-Dikarya fungi were considered unable to produce secondary metabolites (SM); however, this perspective is changing. The main classes of secondary metabolites in fungi include polyketides, nonribosomal peptides, terpenoids and siderophores that serve different biological roles, including iron chelation and plant growth promotion. The same classes of SM are reported for representatives of early-diverging fungal lineages. Encouraged by the advancement in the field, we carried out a systematic survey of SM in Mucoromycotina and corroborated the presence of various SM clusters (SMCs) within the phylum. Among the core findings, considerable representation of terpene and nonribosomal peptide synthetase (NRPS)-like candidate SMCs was found. Terpene clusters with diverse domain composition and potentially highly variable products dominated the landscape of candidate SMCs. A uniform low-copy distribution of siderophore clusters was observed among most assemblies. Mortierellomycotina are highlighted as the most potent SMC producers among the Mucoromycota and as a source of novel peptide products. SMC identification is dependent on gene model quality and can be successfully performed on a batch scale with genomes of different quality and completeness. Full article

(This article belongs to the Section Fungal Genomics, Genetics and Molecular Biology)

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9 pages, 862 KiB

Open AccessEditor’s ChoiceArticle

Validation of the SavvyCheck™ Vaginal Yeast Test for Screening Pregnant Women for Vulvovaginal Candidosis: A Prospective, Cross-Sectional Study

by Philipp Foessleitner, Herbert Kiss, Julia Deinsberger, Julia Ott, Lorenz Zierhut and Alex Farr

J. Fungi 2021, 7(3), 233; https://doi.org/10.3390/jof7030233 - 20 Mar 2021

Cited by 5 | Viewed by 3495

Abstract

Pregnant women have an increased risk of vulvovaginal candidosis. Recurrent candidosis is under debate as a contributor to preterm birth, and vertical transmission may cause diaper dermatitis and oral thrush in the newborn. Apart from cultural methods, the gold standard for diagnosing candidosis [...] Read more.

Pregnant women have an increased risk of vulvovaginal candidosis. Recurrent candidosis is under debate as a contributor to preterm birth, and vertical transmission may cause diaper dermatitis and oral thrush in the newborn. Apart from cultural methods, the gold standard for diagnosing candidosis is Gram staining, which is time-consuming and requires laboratory facilities. The objective of this prospective study was to validate a point-of-care vaginal yeast detection assay (SavvyCheck™ Vaginal Yeast Test) and to evaluate it in asymptomatic pregnant women. We enrolled 200 participants, 100 of whom had vulvovaginal candidosis according to Gram stain (study group) and 100 were healthy pregnant controls (control group). Of these, 22 participants (11%) had invalid test results. The point-of-care test of the remaining 85 and 93 study participants in the study and control groups, respectively, showed a sensitivity of 94.1%, specificity of 98.9%, positive predictive value of 90.3%, and negative predictive value of 99.4% when compared with Gram stain. In conclusion, we found a high correlation between the SavvyCheck™ Vaginal Yeast Test and Gram-stained smears during pregnancy. This suggests a potential role of this point-of-care test as a screening tool for asymptomatic pregnant women in early gestation. Full article

(This article belongs to the Special Issue Epidemiology, Diagnosis of Fungal Infections)

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12 pages, 7023 KiB

Open AccessEditor’s ChoiceArticle

Epidemiological Correlation of Pulmonary Aspergillus Infections with Ambient Pollutions and Influenza A (H1N1) in Southern Taiwan

by Jien-Wei Liu, Yee-Huang Ku, Chien-Ming Chao, Hsuan-Fu Ou, Chung-Han Ho, Khee-Siang Chan and Wen-Liang Yu

J. Fungi 2021, 7(3), 227; https://doi.org/10.3390/jof7030227 - 19 Mar 2021

Cited by 9 | Viewed by 3098

Abstract

An increase in fungal spores in ambient air is reported during a spike in particulate matter (PM_2.5 and PM₁₀) aerosols generated during dust or smog events. However, little is known about the impact of ambient bioaerosols on fungal infections in [...] Read more.

An increase in fungal spores in ambient air is reported during a spike in particulate matter (PM_2.5 and PM₁₀) aerosols generated during dust or smog events. However, little is known about the impact of ambient bioaerosols on fungal infections in humans. To identify the correlation between the incidence of pulmonary aspergillosis and PM-associated bioaerosols (PM_2.5 and PM₁₀), we retrospectively analyzed data between 2015 and 2018 (first stage) and prospectively analyzed data in 2019 (second stage). Patient data were collected from patients in three medical institutions in Tainan, a city with a population of 1.88 million, located in southern Taiwan. PM data were obtained from the Taiwan Air Quality Monitoring Network. Overall, 544 non-repeated aspergillosis patients (first stage, n = 340; second stage, n = 204) were identified and enrolled for analysis. The trend of aspergillosis significantly increased from 2015 to 2019. Influenza A (H1N1) and ambient PMs (PM_2.5 and PM₁₀) levels had significant effects on aspergillosis from 2015 to 2018. However, ambient PMs and influenza A (H1N1) in Tainan were correlated with the occurrence of aspergillosis in 2018 and 2019, respectively. Overall (2015–2019), aspergillosis was significantly correlated with influenza (p = 0.002), influenza A (H1N1) (p < 0.001), and PM_2.5 (p = 0.040) in Tainan City. Using a stepwise regression model, influenza A (H1N1) (p < 0.0001) and Tainan PM₁₀ (p = 0.016) could significantly predict the occurrence of aspergillosis in Tainan. PM-related bioaerosols and influenza A (H1N1) contribute to the incidence of pulmonary aspergillosis. Full article

(This article belongs to the Section Environmental and Ecological Interactions of Fungi)

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12 pages, 884 KiB

Open AccessEditor’s ChoiceArticle

Inocybe brijunica sp. nov., a New Ectomycorrhizal Fungus from Mediterranean Croatia Revealed by Morphology and Multilocus Phylogenetic Analysis

by Armin Mešić, Danny Haelewaters, Zdenko Tkalčec, Jingyu Liu, Ivana Kušan, M. Catherine Aime and Ana Pošta

J. Fungi 2021, 7(3), 199; https://doi.org/10.3390/jof7030199 - 10 Mar 2021

Cited by 18 | Viewed by 4493

Abstract

A new ectomycorrhizal species was discovered during the first survey of fungal diversity at Brijuni National Park (Croatia), which consists of 14 islands and islets. The National Park is located in the Mediterranean Biogeographical Region, a prominent climate change hot-spot. Inocybe brijunica sp. [...] Read more.

A new ectomycorrhizal species was discovered during the first survey of fungal diversity at Brijuni National Park (Croatia), which consists of 14 islands and islets. The National Park is located in the Mediterranean Biogeographical Region, a prominent climate change hot-spot. Inocybe brijunica sp. nov., from sect. Hysterices (Agaricales, Inocybaceae), is described based on morphology and multilocus phylogenetic data. The holotype collection was found at the edge between grassland and Quercus ilex forest with a few planted Pinus pinea trees, on Veli Brijun Island, the largest island of the archipelago. It is easily recognized by a conspicuous orange to orange–red–brown membranaceous surface layer located at or just above the basal part of the stipe. Other distinctive features of I. brijunica are the medium brown, radially fibrillose to rimose pileus; pale to medium brown stipe with fugacious cortina; relatively small, amygdaliform to phaseoliform, and smooth basidiospores, measuring ca. 6.5–9 × 4–5.5 µm; thick-walled, utriform, lageniform or fusiform pleurocystidia (lamprocystidia) with crystals and mostly not yellowing in alkaline solutions; cheilocystidia of two types (lamprocystidia and leptocystidia); and the presence of abundant caulocystidia only in the upper 2–3 mm of the stipe. Phylogenetic reconstruction of a concatenated dataset of the internal transcribed spacer region (ITS), the nuclear 28S rRNA gene (nrLSU), and the second largest subunit of RNA polymerase II (rpb2) resolved I. brijunica and I. glabripes as sister species. Full article

(This article belongs to the Special Issue Biodiversity, Distribution and Conservation of Plants and Fungi; Effects of Global Warming and Environmental Stress)

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19 pages, 6469 KiB

Open AccessEditor’s ChoiceArticle

In Vitro and In Vivo Anti-Candida Activity and Structural Analysis of Killer Peptide (KP)-Derivatives

by Tecla Ciociola, Thelma A. Pertinhez, Tiziano De Simone, Walter Magliani, Elena Ferrari, Silvana Belletti, Tiziana D’Adda, Stefania Conti and Laura Giovati

J. Fungi 2021, 7(2), 129; https://doi.org/10.3390/jof7020129 - 10 Feb 2021

Cited by 9 | Viewed by 3903

Abstract

The previously described decapeptide AKVTMTCSAS (killer peptide, KP), derived from the variable region of a recombinant yeast killer toxin-like anti-idiotypic antibody, proved to exert a variety of antimicrobial, antiviral, and immunomodulatory activities. It also showed a peculiar self-assembly ability, likely responsible for the [...] Read more.

The previously described decapeptide AKVTMTCSAS (killer peptide, KP), derived from the variable region of a recombinant yeast killer toxin-like anti-idiotypic antibody, proved to exert a variety of antimicrobial, antiviral, and immunomodulatory activities. It also showed a peculiar self-assembly ability, likely responsible for the therapeutic effect in animal models of systemic and mucosal candidiasis. The present study analyzed the biological and structural properties of peptides derived from KP by substitution or deletion of the first residue, leaving unchanged the remaining amino acids. The investigated peptides proved to exert differential in vitro and/or in vivo anti-Candida activity without showing toxic effects on mammalian cells. The change of the first residue in KP amino acidic sequence affected the conformation of the resulting peptides in solution, as assessed by circular dichroism spectroscopy. KP-derivatives, except one, were able to induce apoptosis in yeast cells, like KP itself. ROS production and changes in mitochondrial transmembrane potential were also observed. Confocal and transmission electron microscopy studies allowed to establish that selected peptides could penetrate within C. albicans cells and cause gross morphological alterations. Overall, the physical and chemical properties of the first residue were found to be important for peptide conformation, candidacidal activity and possible mechanism of action. Small antimicrobial peptides could be exploited for the development of a new generation of antifungal drugs, given their relative low cost and ease of production as well as the possibility of devising novel delivery systems. Full article

(This article belongs to the Special Issue Antifungal Peptides 2020)

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15 pages, 3300 KiB

Open AccessEditor’s ChoiceArticle

In Vitro Characterization of Twenty-One Antifungal Combinations against Echinocandin-Resistant and -Susceptible Candida glabrata

by Hazim O. Khalifa, Hidetaka Majima, Akira Watanabe and Katsuhiko Kamei

J. Fungi 2021, 7(2), 108; https://doi.org/10.3390/jof7020108 - 2 Feb 2021

Cited by 24 | Viewed by 4365

Abstract

This study was designed to analyze the interaction of 21 antifungal combinations consisting of seven major antifungal agents against 11 echinocandin- susceptible and six-resistant C. glabrata isolates. The combinations were divided into five major groups and were evaluated by checkerboard, disc diffusion, and [...] Read more.

This study was designed to analyze the interaction of 21 antifungal combinations consisting of seven major antifungal agents against 11 echinocandin- susceptible and six-resistant C. glabrata isolates. The combinations were divided into five major groups and were evaluated by checkerboard, disc diffusion, and time-killing assays. Synergy based on the fractional inhibitory concentration index of ≤0.50 was observed in 17.65–29.41% of the cases for caspofungin combinations with azoles or amphotericin B. Amphotericin B combination with azoles induced synergistic interaction in a range of 11.76–29.41%. Azole combinations and 5-flucytosine combinations with azoles or amphotericin B did not show synergistic interactions. None of the 21 combinations showed antagonistic interactions. Interestingly, 90% of the detected synergism was among the echinocandin-resistant isolates. Disk diffusion assays showed that the inhibition zones produced by antifungal combinations were equal to or greater than those produced by single drugs. The time-killing assay showed the synergistic action of caspofungin combination with fluconazole, voriconazole, and posaconazole, and the amphotericin B-5-flucytosine combination. Furthermore, for the first time, this assay confirmed the fungicidal activity of caspofungin-voriconazole and amphotericin B-5-flucytosine combinations. The combination interactions ranged from synergism to indifference and, most importantly, no antagonism was reported and most of the synergistic action was among echinocandin-resistant isolates. Full article

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25 pages, 5933 KiB

Open AccessEditor’s ChoiceArticle

The Identification of Genetic Determinants of Methanol Tolerance in Yeast Suggests Differences in Methanol and Ethanol Toxicity Mechanisms and Candidates for Improved Methanol Tolerance Engineering

by Marta N. Mota, Luís C. Martins and Isabel Sá-Correia

J. Fungi 2021, 7(2), 90; https://doi.org/10.3390/jof7020090 - 27 Jan 2021

Cited by 19 | Viewed by 5007

Abstract

Methanol is a promising feedstock for metabolically competent yeast strains-based biorefineries. However, methanol toxicity can limit the productivity of these bioprocesses. Therefore, the identification of genes whose expression is required for maximum methanol tolerance is important for mechanistic insights and rational genomic manipulation [...] Read more.

Methanol is a promising feedstock for metabolically competent yeast strains-based biorefineries. However, methanol toxicity can limit the productivity of these bioprocesses. Therefore, the identification of genes whose expression is required for maximum methanol tolerance is important for mechanistic insights and rational genomic manipulation to obtain more robust methylotrophic yeast strains. The present chemogenomic analysis was performed with this objective based on the screening of the Euroscarf Saccharomyces cerevisiae haploid deletion mutant collection to search for susceptibility phenotypes in YPD medium supplemented with 8% (v/v) methanol, at 35 °C, compared with an equivalent ethanol concentration (5.5% (v/v)). Around 400 methanol tolerance determinants were identified, 81 showing a marked phenotype. The clustering of the identified tolerance genes indicates an enrichment of functional categories in the methanol dataset not enriched in the ethanol dataset, such as chromatin remodeling, DNA repair and fatty acid biosynthesis. Several genes involved in DNA repair (eight RAD genes), identified as specific for methanol toxicity, were previously reported as tolerance determinants for formaldehyde, a methanol detoxification pathway intermediate. This study provides new valuable information on genes and potential regulatory networks involved in overcoming methanol toxicity. This knowledge is an important starting point for the improvement of methanol tolerance in yeasts capable of catabolizing and copying with methanol concentrations present in promising bioeconomy feedstocks, including industrial residues. Full article

(This article belongs to the Special Issue Yeast Biorefineries)

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16 pages, 2533 KiB

Open AccessEditor’s ChoiceArticle

Preterm Infants Harbour a Rapidly Changing Mycobiota That Includes Candida Pathobionts

by Stephen A. James, Sarah Phillips, Andrea Telatin, David Baker, Rebecca Ansorge, Paul Clarke, Lindsay J. Hall and Simon R. Carding

J. Fungi 2020, 6(4), 273; https://doi.org/10.3390/jof6040273 - 9 Nov 2020

Cited by 29 | Viewed by 5016

Abstract

Fungi and the mycobiome are a fundamental part of the human microbiome that contributes to human health and development. Despite this, relatively little is known about the mycobiome of the preterm infant gut. Here, we have characterised faecal fungal communities present in 11 [...] Read more.

Fungi and the mycobiome are a fundamental part of the human microbiome that contributes to human health and development. Despite this, relatively little is known about the mycobiome of the preterm infant gut. Here, we have characterised faecal fungal communities present in 11 premature infants born with differing degrees of prematurity and mapped how the mycobiome develops during early infancy. Using an ITS1 sequencing-based approach, the preterm infant gut mycobiome was found to be often dominated by a single species, typically a yeast. Candida was the most abundant genus, with the pathobionts C.albicans and C.parapsilosis highly prevalent and persistent in these infants. Gestational maturity at birth affected the distribution and abundance of these Candida, with hospital-associated C.parapsilosis more prevalent and abundant in infants born at less than 31 weeks. Fungal diversity was lowest at 6 months, but increased with age and change of diet, with food-associated Saccharomycescerevisiae most abundant in infants post weaning. This study provides a first insight into the fungal communities present within the preterm infant gut, identifying distinctive features including the prominence of pathobiont species, and the influence age and environmental factors play in shaping the development of the mycobiome. Full article

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