Band 53, Heft 6 - Special Issue: Marine Mycology

No abstract available

The few studies on deep-sea fungi in recent years (using either culturing or molecular signatures) have provided evidence on their occurrence. A majority of culture-dependent and culture-independent fungi recovered have homology to terrestrial species, indicating possible arrival in deep-sea either via wind or terrestrial runoffs. However, the presence of novel fungal sequences with <97% similarity to previously identified fungal sequences in public databases has also been reported. Several filamentous fungi and yeasts recovered from deep-sea sediments of the Central Indian Basin from ∼5000 m grew under hydrostatic pressures of 20–40 MPa and 5°C. Some of these fungi had unusual morphology during initial culturing and also when grown at 20 MPa/5°C. Direct detection of fungal hyphae in deep-sea sediments is a daunting task as they are present in low abundance. We demonstrated the occurrence of fungal hyphae in deep-sea sediments by direct staining of the sediments with Calcofluor White, a fluorescent optical brightener. This review presents data on the occurrence, diversity and adaptations of fungi to various deep-sea habitats, with special emphasis on their possible ecological role under these extreme environmental conditions.

In an ongoing survey of marine mangrove fungi in Taiwan, a fungus with light-coloured ascomata, resembling members of the Hypocreales, was found on twigs of Kandelia obovata . Based on morphological characteristics and partial nuclear small and large subunit ribosomal DNA data, the fungus is described as a new genus and species, Sedecimiella taiwanensis, and placed in the Hypocreales (Hypocreomycetidae, Ascomycota). Phylogenetic analyses based on LSU/SSU sequences did not resolve the familial placement of S. tawianensis within the Hypcreales, but it may be related to the Niessliaceae. The characteristic features of S. tawianensis are orange to dark-brown colour, soft-texture and perithecial ascomata with the inner wall layer of the neck extending into the upper part of the centrum; cylindrical, 16-spored, unitunicate asci without an apical pore; and hyaline, smooth-walled and globose ascospores.

Three dibenzofurans hitherto undescribed from nature and one known butyrolactone were isolated from the extract of the ascomycete Super1F1-09 isolated from the Fijian marine sponge Acanthella cavernosa . The isolated compounds were identified as 3,9-dimethyldibenzo[ b,d ]furan-1,7-diol ( 1 ), 3-(hydroxymethyl)-9-methyldibenzo[ b,d ]furan-1,7-diol ( 2 ), 1,7-dihydroxy-9-methyldibenzo[ b,d ]furan-3-carboxylic acid ( 3 ), and the known butyrolactone I ( 4 ) using different NMR spectroscopic techniques and accurate mass spectrometric analysis. 1 was synthesized together with structurally related dibenzofurans 6 – 8 . 1 and 4 had moderate antibacterial activity toward Mycobacterium marinum and Staphylococcus aureus , whereas 2 and 3 proved inactive. In addition, all compounds had moderate inhibitory properties against epidermal growth factor receptor tyrosine kinase.

In a systematic screening effort, extracts of marine fungi from Malaysia were investigated for antimicrobial activity and potentially active secondary metabolites. In preliminary experiments, the plug assay method was employed to screen 152 strains for antimicrobial activity. Of these, 82 exhibited biological activity, with most of the active strains (90.2%) having antibacterial activity, mainly towards Gram-positive bacteria, while only 9.6% had antifungal activity. On the basis of these results, five marine fungi, Fasciatispora nypae , Caryosporella rhizophorae , Melaspilea mangrovei , Leptosphaeria sp. and ascomycete strain 19 (NF) were selected for further investigation to confirm their biological activity by the disc diffusion assay method. The selected species had various degrees of activity against the test microorganisms, depending on culture conditions (stationary vs. shaking cultures) and incubation time (10–25 days). Only F. nypae showed a wider range of antifungal and antibacterial activity as compared to the remaining fungal strains under investigation. Therefore, bioactivity-guided fractionation was undertaken to isolate the active principles, resulting in the characterisation of 2,2,7-trimethyl-2H-chromen-5-ol ( 1 ) which had antimicrobial activity towards test microorganisms. The structure of 1 , which previously had only been reported as a synthetic intermediate, but not as a natural product, was elucidated by mass spectrometry in conjunction with one- and two-dimensional NMR spectroscopy.

We documented the diversity of marine fungi in various mangroves from the east and west coasts of Malaysia in the period May 2008–June 2009; we sampled at Cape Rachado, Morib, Redang Island, Bachok and Cape Layak-Layak. A total of 438 samples were examined. These comprised prop roots, pneumatophores, subterranean roots, rhizomes, overhanging branches and twigs of mangrove trees and driftwood. Seventy-seven higher marine fungal taxa were recorded, comprising 58 ascomycetes, two basidiomycetes and 17 anamorphic fungi. Among these, 38 were only partially identified/unidentified, indicating these might be new species. The most common species (>10% occurrence) were Aigialus grandis , A. parvus , Dactylospora haliotrepha , Kallichroma tethys , Halocyphina villosa , Verruculina enalia and Ascocratera manglicola . Species diversity and richness were highest in Bachok, while Cape Layak-Layak had the highest species evenness. Sorenson's similarity indices between sites were low, implicating low similarity between fungal communities among the study sites.

We studied patterns of fungal colonization, mass loss and biochemical changes during decomposition of the dominant mangrove sedge Cyperus malaccensis in a mangal located in southwestern India. Litter bags containing dried bracts, basal stem and top stem were introduced into a sedge sward in a mid-tidal zone for periods of up to 8 weeks (April–June 2005). After retrieval of sedge substrates and incubation in the laboratory, 19 fungi (10 anamorphs, 8 ascomycetes and one zygomycete) were found. Terrestrial fungi dominated over the first 2–3 weeks. Later, in spite of falling water temperatures and salinity, they were replaced by typical mangrove/marine ascomycetes and anamorphs. Up to 79% of bract mass loss occurred in 4 weeks; respective losses for basal stems and top stems were 88% and 51% through 8 weeks. The estimated durations of 50% mass loss ( t 50 ) were 4.5, 10.9 and 22.9 days for bract, basal stem and top stem, respectively. Accordingly, there were significant differences in daily decay coefficients ( k ) among substrates. Organic carbon and phenolics decreased steadily in all substrates. Phosphorus concentrations decreased, attained a minimum and increased again, reaching final concentrations similar to initial values. Nitrogen concentration increased through the end of the experiment. Cellulase, xylanase and pectinase in all sedge substrates generally peaked within 4 weeks. This is the first study on decomposition of the macrophyte C. malaccensis .

The mangroves at Del Carmen, Siargao Island support a high fungal diversity, with 66 taxa identified in this study. In total, 46 species are new records for the Philippines, 2 of which ( Swampomyces sp. and Halocyphina sp.) could be new species. In total, 10 taxa were frequently collected, whereas some 56 taxa were occasionally collected. The fungal taxa collected from Rhizophora apiculata , Xylocarpus granatum , Nypa fruticans and driftwood were found to differ. The distributions of taxa associated with R. apiculata and X. granatum were differentiated on a vertical gradient; however, in N. fruticans vertical distribution was not clear cut.

Senescent and decaying substrata were collected in selected Malaysian mangroves (prop roots, pneumatophores, overhanging branches and twigs of mangrove trees, driftwood) to study the diversity of marine mangrove fungi. One hundred and thirty-nine marine fungi were fully identified to specific level (115 Ascomycota, 2 Basidiomycota, 22 anamorphic taxa). Based on percentage of occurrence, the most common species were Lignincola laevis (16.8%), Verruculina enalia (13.3%), Trichocladium achrasporum (12.1%), Savoryella lignicola (11.8%), Dictyosporium pelagicum (11.2%) , Halocyphina villosa (11.0%) and Lulworthia grandispora (10.9%). Among the samples, 84.2% supported an average number of 2.8 fungal species per sample. Of the 139 fungi identified in this study, circa 84% (117 species) are only found in the tropics/subtropics, mostly as mangrove species. Factors affecting the distribution and abundance of mangrove fungi are discussed, including: substrate specificity, sampling frequency and intensity, vertical distribution and geographical locations.

We examined the distribution of endophytic fungi in the leaves of mangrove forest trees growing at three different locations (Chanthaburi Province, Prachuap Khiri Khan Province and Ranong Province) in Thailand. Three thousand and nine-hundred leaf segments from 10 different hosts belonging to seven families, Rhizophoraceae ( Rhizophora apiculata , R. mucronata , Ceriops decandra ), Sonneratiaceae ( Sonneratia alba ), Combretaceae ( Lumnitzera littorea ), Avicenniaceae ( Avicennia alba ), Acanthaceae ( Acanthus ilicifolius ), Meliaceae ( Xylocarpus granatum and Xylocarpus moluccensis ) and Malvaceae ( Thespesia populneoides ), were screened for the presence of fungal endophytes. The dominant endophytes varied by host type. Phyllosticta was the most frequently isolated fungus from plants at all sites. The common fungal endophyte genera were Cladosporium , Colletotrichum , Phomopsis and Xylaria . Most endophytic isolates in mangrove leaves were recovered from Ranong Province. The antimicrobial potential of 71 endophytic fungi isolated from mangrove plants towards selected bacteria ( Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus ) was tested using ethyl acetate extracts of fungi cultivated under static conditions. All test bacteria were inhibited by a Cladosporium sp. isolated from the leaves of T. populneoides and an endophytic Xylaria sp. 1 isolated from A. ilicifolius leaves caused considerable inhibition to Gram-positive and Gram-negative bacteria. Additionally, the crude extracts of 84 endophytic fungi were tested for anticancer activities by the MTT assay against A375 (human malignant melanoma), SW620 (human colorectal adenocarcinoma), Kato III (human gastric carcinoma), HepG2 (human liver hepatoblastoma) and Jurkat (human acute T cell leukemia). Most extracts had cytotoxicity against some cancer cell lines.

Few studies have been conducted to determine how fungal populations respond over the long-term to oil spills in tropical coastal habitats. The present study aimed to provide information on temporal changes in a fungal community affected by an oil spill, and to determine whether there was any recovery of normal mycoflora in the oil-affected sites in Guimaras, the Philippines. Changes in fungal communities are described according to species composition and fungal load (CFUs ml -1 seawater or g -1 soil) by site and sample type. Samples were collected at the same eight sites in 2009, and comprised beach water, beach soil, mangrove surface soil and mangrove sub-surface soil. Fungi were enumerated and isolated using the spread plate serial dilution technique and identified based on colony and microscopic characteristics using available keys and monographs. In general, fungal density appears to have increased over the three-year period and there was a continuing dominance of members of the hyphomycetes, resembling previous data from 2006, though with some shifts in species composition. The observed changes in fungal community composition and density may be signs of initial recovery and re-establishment of a normal fungal flora among the disturbed areas.

We developed a quantitative scale for estimating disturbance level on 10 public-access tourist beaches. For this purpose, we estimated frequency of occurrence values for sand-inhabiting obligate ascomycetes annually through 10 years (2000–2009). In particular, we determined the presence of Corollospora maritima on each beach. A positive correlation between sandy beach disturbance level and fungal species frequencies of occurrence was demonstrated. Progressively higher frequencies of occurrence for C. maritima were obtained from increasingly less disturbed beaches. Hence, intertidal autochthonous species have potential use as bioindicators, and we selected C. maritima to represent this group of marine obligate fungi as a bioindicator of sand beach degradation.

Three Schizochytrium species isolated from three mangrove sites in Taiwan, Erjen River in Kaohsiung (isolate EJ56), Yantian Ecological Park in Tainan (isolate YT90), and Chunan mangrove in Miaoli (isolate CN75), were screened for their tolerance to heavy metals. Two common heavy metal pollutants present in Taiwan rivers were used in this study: copper [Cu(II)] and zinc [Zn(II)]. Growth at varying concentrations of these heavy metals was assessed, as well as their effects on cell morphology. There was a significant reduction in growth of isolate YT90 exposed to minimal concentrations (0.5–8 ppm) of Cu(II) and Zn(II), and isolate CN75 exposed to Cu(II). Isolate EJ56 had growth comparable to the control at 0.5–8 ppm of Cu(II) and Zn(II). Tolerance of the test isolates varied between each of the heavy metals tested. YT90 was most tolerant to Cu(II), and CN75 to Zn(II). Light and scanning electron micrographs of Schizochytrium cells exposed to high levels of heavy metals (>32 ppm) showed formation of holes in the cell wall, as well as shrinkage and general deformation of the cell structure. At the highest heavy metal concentrations tested (256– 384 ppm), cell lysis occurred, resulting in leakage of cellular content. Hence, high concentrations of heavy metal pollutants in mangrove habitats will result in growth retardation of thraustochytrids and, eventually, cell death.

Ice-ice disease in cultivated seaweeds is often associated with environmental stress and infection by pathogenic marine bacteria. No studies have associated the disease with marine fungi. Our study aimed to isolate marine fungi from cultivated Kappaphycus species and assess their ability to induce the disease. Kappaphycus alvarezii and K. striatum were collected from Calatagan, Batangas, Philippines. Following washing with sterile artificial seawater and inoculation into culture media, 18 morphospecies of marine-derived fungi (MDF) were isolated. Fungal diversity (H s =2.4) in infected seaweeds was higher than in healthy specimens. K. striatum (orange variety) had the highest incidence of MDF with 67 isolates, while K. striatum (green variety) had the lowest incidence with only 17 isolates. The ability of MDF to produce carrageenolytic and cellulolytic enzymes and utilize algal components was also tested. Of the 18 MDF selected, three had carrageenolytic activity and ten had cellulolytic activity. Most isolates utilized carrageenan, agar, and cellulose. Among the 10 MDF assayed for their ability to induce ice-ice disease, three isolates ( Aspergillus ochraceus, A. terreus and Phoma sp.) induced ice-ice disease symptoms (thallus bleaching) in healthy, non-axenic cultures of K. alvarezii .

This is a first report on the fungal diversity of the Kara Sea, one of the most inclement seas off Russia. Eighteen bottom sediment samples taken from three different areas were examined. Using a direct plating method, I isolated 539 fungal strains (46 species in 24 genera of Zygomycota, Ascomycota and anamorphic fungi). Tolypocladium inflatum , Pseudogymnoascus roseus , Pseudeurotium zonatum and mycelia sterilia were the most frequent taxa in the samples.

No abstract available