Effect of a siderophore producer on animal cell apoptosis: a possible role as anti-cancer agent.

Iron plays an essential role in the proliferation of aggressive tumors therefore it represents an ideal target for cancer therapy. Cell free supernatants from a siderophore producing actinobacterium previously isolated from Thailand were tested against six human cancer cell lines including malignant melanoma A 375 (ATCC no.: CRL-1619), colorectal adenocarcinoma SW620 (ATCC no.: CCL-227), gastric carcinoma Katob III (ATCC no.: HTB-103), liver hepatoblastoma HepG2 (ATCC no.: HB-8065), breast carcinoma BT474 (ATCC no.: HTB-20) and Acute T cell leukemia Jurkat (ATCC no.: CRL-2063). Following treatment of cells with the bacterial culture supernatant the cell viability of A375 cells was dramatically decreased with cell survival of less than 34 % within 48 h. The rest of the cell lines were largely unaffected. Therefore it is suggested that the actinobacterium produced a cytotoxic compound responsible for the cell death by inducing apoptotic activity. We further speculate that this compound was desferioxamine E as the bacterium is known to produce this compound under the culture conditions used

Antimicrobial activity from endophytic fungi isolated from plant leaves in Dipterocarpous forest at Viengsa district Nan province, Thailand

Eleven fungal endophytes representing different morphotaxa were characterized from 68 cultures, which were isolated from 4 species of Dipterocapous trees (Dipterocarpus tuberculatus Roxb., Shorea obtusa Wall., Shorea siamensis Miq. and Dalbergia oliveri Gamble.) growing in the Dipterocapous forest at Viengsa district, Nan province. Species of Phyllosticta spp. (15 isolates), Nodulisporium spp. (13 isolates) and Xylaria sp.1 (10 isolates) were the most frequently found. All endophytic fungal isolates were tested for potential production of bioactive metabolites. They were tested for antimicrobial activity against pathogenic microorganisms such as Staphylococcus aureus, Bacillus subtilis, Pseudomonas aerogenosa, Escherichia coli and Candida albicans by the paper disk susceptibility test. They inhibited the growth of Gram positive bacteria more than Gram negative bacteria. Candida albicans was inhibited only by Nodulissporium sp. (DT6) and Xylaria sp.1 (DO9)

Molecular phylogeny and re-assessment of some Scleroderma spp. (Gasteromycetes)

9 pages, 3 figures, 1 table.[EN] The fungal genus Scleroderma is cosmopolitan in temperate and tropical regions and forms ectomycorrhizal associations with a wide range of forest trees. To delimit phylogenetic Scleroderma species and identification, 43 basidiomes were chosen of different geographical origins and their rDNA internal transcribed spacer (ITS) were sequenced. Phylogenetic analyses of these sequences together with additional GenBank sequences identified 11 taxa. A strong phylogenetic pattern was observed related to a character of their basidiospore ornamentation.[ES] Las especies del género Scleroderma son cosmopolitas y forman ectomicorrizas con un amplio rango de hospedantes, tanto de zonas templadas como tropicales. Para delimitar las especies filogenéticas y la identificación de las mismas, se han seleccionado 43 basidiomas, de diferente origen geográfico, y se han secuenciado las regiones de transcripción interna del ADN ribosómico nuclear. Los análisis filogenéticos de estas colecciones, junto con secuencias obtenidas del GenBank, permiten identificar 11 especies, agrupadas en tres clados relacionados con el tipo de ornamentación de la basidióspora.CP is indebted to the Commission on Higher Education of Thailand, Royal Thai government for financial support and to the European Commission Human Potential Programme for supporting part of this study at the Real Jardín Botánico de Madrid (BIODIBERIA).Peer reviewe

Rapid screening for genotypes as possible markers of virulence in the neurotropic black yeast Exophiala dermatiddis using PCR-RFLP

A simple method for fungal genotype screening was developed for the black yeast Exophiala dermatitidis based on RFLP of ribosomal ITS regions currently used as potential virulence markers. In a study set of 502 strains of the species, two main genotypes were recognized. Only 0.97% of lanes were difficult to interpret as they did not clearly present one of the expected genotypes. Twenty strains were deviating and proved to be E. spinifera after sequencing. Eight common. related species (based on SSU data) with clinical significance yielded different patterns with TaqI digestion, and thus the method is also usable for routine diagnostics. (C) 2009 Published by Elsevier B.V

Fungi in Thailand: A Case Study of the Efficacy of an ITS Barcode for Automatically Identifying Species within the Annulohypoxylon and Hypoxylon Genera

<div><p>Thailand, a part of the Indo-Burma biodiversity hotspot, has many endemic animals and plants. Some of its fungal species are difficult to recognize and separate, complicating assessments of biodiversity. We assessed species diversity within the fungal genera <em>Annulohypoxylon</em> and <em>Hypoxylon</em>, which produce biologically active and potentially therapeutic compounds, by applying classical taxonomic methods to 552 teleomorphs collected from across Thailand. Using probability of correct identification (PCI), we also assessed the efficacy of automated species identification with a fungal barcode marker, ITS, in the model system of <em>Annulohypoxylon</em> and <em>Hypoxylon</em>. The 552 teleomorphs yielded 137 ITS sequences; in addition, we examined 128 GenBank ITS sequences, to assess biases in evaluating a DNA barcode with GenBank data. The use of multiple sequence alignment in a barcode database like BOLD raises some concerns about non-protein barcode markers like ITS, so we also compared species identification using different alignment methods. Our results suggest the following. (1) Multiple sequence alignment of ITS sequences is competitive with pairwise alignment when identifying species, so BOLD should be able to preserve its present bioinformatics workflow for species identification for ITS, and possibly therefore with at least some other non-protein barcode markers. (2) Automated species identification is insensitive to a specific choice of evolutionary distance, contributing to resolution of a current debate in DNA barcoding. (3) Statistical methods are available to address, at least partially, the possibility of expert misidentification of species. Phylogenetic trees discovered a cryptic species and strongly supported monophyletic clades for many <em>Annulohypoxylon</em> and <em>Hypoxylon</em> species, suggesting that ITS can contribute usefully to a barcode for these fungi. The PCIs here, derived solely from ITS, suggest that a fungal barcode will require secondary markers in <em>Annulohypoxylon</em> and <em>Hypoxylon</em>, however. The URL <a href="http://tinyurl.com/spouge-barcode">http://tinyurl.com/spouge-barcode</a> contains computer programs and other supplementary material relevant to this article.</p> </div

Elucidation of distribution patterns and possible infection routes of the neurotropic black yeast Exophiala dermatitidis using AFLP

Distribution of populations of the opportunistic black yeast Exophiala dermatitidis was studied using AFLP. This fungus has been hypothesized to have a natural habitat in association with frugivorous birds and bats in the tropical rain forest, and to emerge in the human-dominated environment, where it occasionally causes human pulmonary or fatal disseminated and neurotropic disease. The hypothesis of its natural niche was investigated by comparing a set of 178 strains from natural and human-dominated environments in Thailand with a worldwide selection of 107 strains from the reference collection of the CBS Fungal Biodiversity Centre, comprising 75.7 % clinical isolates. Many isolates had unique AFLP patterns and were too remote for confident comparison. Eight populations containing multiple isolates could be distinguished, enabling determination of geographic distributions of these populations. Some of the populations were confined to Thailand, while others occurred worldwide. The local populations from Thailand contained strains from natural and urban environments, suggesting an environmental jump of the fungus. Strains from human brain belonged to widely dispersed populations. In some cases cerebral isolates were identical to isolates from the human intestinal tract. The possibility of cerebral infection through intestinal translocation was thus not excluded