95 research outputs found

    Aquatic fungi from peat swamp palms: Phruensis brunneispora gen. et sp. nov. and its hyphomycete anamorph

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    Phruensis brunneispora is a new genus and species occurring on decaying trunks of the palm Licuala longecalycata in Sirindhorn Peat Swamp Forest, Thailand. We compare the genus with other aquatic ascomycetes with falcate septate ascospores: Pseudohalonectria and Ophioceras. Ascospores differ from species in these genera in being brown with lighter end cells. Also, the ascus pore is subapical, with a channel leading to the apex. Lollipopaia minuta differs from Phruensis brunneispora in that the ascomata are borne in a stroma, asci have an apical pore and the ascospores are hyaline. No genus was found to accommodate the new species. Molecular analysis of rDNA ribosomal 18S confirmed the exclusion of the new species from Pseudohalonectria, and Ophioceras and Lollipopaia minuta formed a sister group with it. Phruensis brunneispora and Lollipopaia minuta grouped in the Diaporthales with 100% bootstrap support. Therefore, both morphological and molecular evidence supports erecting a new genus to accommodate this taxon. A hyaline Phialophora-like anamorph was formed when single ascospores were plated out on agar. The taxon is described and illustrated with light micrographs.published_or_final_versio

    Antifungal activity and molecular identification of endophytic fungi from the angiosperm Rhodomyrtus tomentosa

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    Problems associated with fungal resistance to antifungal agents are increasing worldwide. There is need to find sources of novel antifungal drugs and endophytic fungi could be another interesting source. In this study, 213 culturable endophytic fungi isolated from leaves and branches of Rhodomyrtus tomentosa from Thailand were screened for their ability to produce antifungal agents. Crude extracts from 177 out of 213 fungal isolates exhibited inhibitory activity against human pathogenic fungi, evaluated by a microbroth dilution method. Of the 349 active extracts out of 617 extracts tested, 43.5% inhibited Penicillium marneffei; 16.5 to 20.8% inhibited two strains of Cryptococcus neoformans; 6.0% Microsporum gypseum; 5.0% Candida albicans, with minimal inhibitory concentrations (MIC) of 1 to 200 μg/ml. 22 endophytic fungi showing strong antifungal activity (MICs of 1 to 8 μg/ml) were identified by morphological and molecular methods. They mainly belonged to the genera Colletotrichum, Diaporthe, Guignardia and Phomopsis. The results of this work indicate that endophytic fungi from R. tomentosa can be a good source of potential antifungal natural products.Keywords: Rhodomyrtus tomentosa, antifungal activity, endophytic fungi, molecular identificatio

    Molecular systematics of the marine Dothideomycetes

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    Phylogenetic analyses of four nuclear genes, namely the large and small subunits of the nuclear ribosomal RNA, transcription elongation factor 1-alpha and the second largest RNA polymerase II subunit, established that the ecological group of marine bitunicate ascomycetes has representatives in the orders Capnodiales, Hysteriales, Jahnulales, Mytilinidiales, Patellariales and Pleosporales. Most of the fungi sequenced were intertidal mangrove taxa and belong to members of 12 families in the Pleosporales: Aigialaceae, Didymellaceae, Leptosphaeriaceae, Lenthitheciaceae, Lophiostomataceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae, Phaeosphaeriaceae, Pleosporaceae, Testudinaceae and Trematosphaeriaceae. Two new families are described: Aigialaceae and Morosphaeriaceae, and three new genera proposed: Halomassarina, Morosphaeria and Rimora. Few marine species are reported from the Dothideomycetidae (e.g. Mycosphaerellaceae, Capnodiales), a group poorly studied at the molecular level. New marine lineages include the Testudinaceae and Manglicola guatemalensis in the Jahnulales. Significantly, most marine Dothideomycetes are intertidal tropical species with only a few from temperate regions on salt marsh plants (Spartina species and Juncus roemerianus), and rarely totally submerged (e.g. Halotthia posidoniae and Pontoporeia biturbinata on the seagrasses Posidonia oceanica and Cymodocea nodosum). Specific attention is given to the adaptation of the Dothideomycetes to the marine milieu, new lineages of marine fungi and their host specificity

    Molecular systematics of the marine Dothideomycetes

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    Phylogenetic analyses of four nuclear genes, namely the large and small subunits of the nuclear ribosomal RNA, transcription elongation factor 1-alpha and the second largest RNA polymerase II subunit, established that the ecological group of marine bitunicate ascomycetes has representatives in the orders Capnodiales, Hysteriales, Jahnulales, Mytilinidiales, Patellariales and Pleosporales. Most of the fungi sequenced were intertidal mangrove taxa and belong to members of 12 families in the Pleosporales: Aigialaceae, Didymellaceae, Leptosphaeriaceae, Lenthitheciaceae, Lophiostomataceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae, Phaeosphaeriaceae, Pleosporaceae, Testudinaceae and Trematosphaeriaceae. Two new families are described: Aigialaceae and Morosphaeriaceae, and three new genera proposed: Halomassarina, Morosphaeria and Rimora. Few marine species are reported from the Dothideomycetidae (e.g. Mycosphaerellaceae, Capnodiales), a group poorly studied at the molecular level. New marine lineages include the Testudinaceae and Manglicola guatemalensis in the Jahnulales. Significantly, most marine Dothideomycetes are intertidal tropical species with only a few from temperate regions on salt marsh plants (Spartina species and Juncus roemerianus), and rarely totally submerged (e.g. Halotthia posidoniae and Pontoporeia biturbinata on the seagrasses Posidonia oceanica and Cymodocea nodosum). Specific attention is given to the adaptation of the Dothideomycetes to the marine milieu, new lineages of marine fungi and their host specificity

    ความสัมพันธุ์ทางสายพันธ์ของราทะเลแอสโคไมโคตา

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    Doctor of Philosophy (Microbiology

    Antimicrobial potential of endophytic fungi derived from three seagrass species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii.

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    Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodoceaserrulata (Family Cymodoceaceae), Halophilaovalis and Thalassiahemprichii (Family Hydrocharitaceae) were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporumgypseum and Penicilliummarneffei. Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C. serrulata, Trichoderma spp. PSU-ES8 and PSU-ES38 from H. ovalis, and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T. hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC) of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses

    <span style="font-size:12.0pt;font-family:"Times New Roman";mso-bidi-font-weight: bold" lang="EN-US">Diversity and antimicrobial activity of endophytic fungi isolated from <span style="font-size:12.0pt;font-family:"Times New Roman";mso-bidi-font-weight: bold" lang="EN-US">the seagrass <i>Enhalus acoroides</i> </span></span>

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    785-797Endophytic fungi were isolated from the seagrass, Enhalus acoroides, collected from Trang province, Thailand. Forty-seven endophytic isolates cultured were classified into 17 phylogenetically diverse genera based on their morphology and molecular analysis of the ITS regions of the rDNA. Most common species were Penicillium (6 isolates), Nigrospora (5), and Fusarium (4) and 2 with unknown taxonomic affinity. Crude extracts including culture media and cells of all isolates were tested for their antimicrobial activities using a colorimetric broth microdilution method against ten potential human pathogens. Extracts from 38 isolates (80.85%) showed antimicrobial activity with minimum inhibitory concentration (MIC) values ranging from 4 to 200 μg mL-1. Nigrospora sp. PSU-ES5 produced the most active extracts against Microsporum gypseum (MIC 4 to 8 μg mL-1). Endophytic fungi from seagrasses such as E. acoroides could therefore be a good source for obtaining antimicrobial natural products
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