Production of a fungistatic substance by Pseudallescheria boydii isolated from soil amended with vegetable tissues and its significance.
ABSTRACT Four fungal isolates that were able to use vegetable tissues for multiplication in soil were isolated and identified as Pseudallescheria boydii based on morphological characteristics and ITS sequence similarity. When grown in broth prepared from the same vegetable tissues used in soil amendment, all these isolates of P. boydii produced a substance capable of reducing the disease incidence of black leaf spot of spoon cabbage caused by Alternaria brassicicola and inhibiting the germination of A. brassicicola conidia. The substance, which was fungistatic, was very stable under high temperature and high or low pH value. It was soluble in polar solvents and insoluble in non-polar solvents. Molecular weight estimation and ion exchange ability tests suggest that the fungistatic compound has a molecular weight between 500 and 1,000 and has no charge on its molecule. Results from this study suggest the possession of a strong competitive saprophytic ability by P. boydii, which in turn may explain the widespread occurrence of this human pathogen in soil. Production of a fungistatic substance when P. boydii was grown in broth prepared from vegetable tissues suggests the importance of antibiotic production in its competitive saprophytic colonization of organic matters in soil.
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ABSTRACT: Based on the morphological, physiologic, and molecular (beta-tubulin gene) study of 141 isolates of the Pseudallescheria boydii species complex (including several synonyms) and relatives, the new species Scedosporium dehoogii is proposed. Scedosporium apiospermum and P. boydii are considered two different species and the new name Scedosporium boydii is proposed for the anamorph of the latter species. A summary of the key morphological and physiological features for distinguishing the species of Pseudallescheria/Scedosporium is provided.Journal of clinical microbiology 03/2008; 46(2):766-71. · 4.16 Impact Factor
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ABSTRACT: The main purpose of the present paper is to establish the connection between phylogenetic and morphological data and ecological features of strains of Pseudallescheria, Petriella, and Scedosporium. For the phylogenetic analysis sequences of the ITS region and the large subunit (partial sequences) of the rDNA were used. Cultural characteristics were observed on MEA 2 % and Weitzman-Silva Hutner Agar. Results showed, that three major groups could be differentiated, corresponding to Pseudallescheria, Petriella and S. prolificans. Among Petriella species only Pe. setifera is reasonably delimited. Pe. musispora was found to be synonymous with Pe. setifera. S. prolificans proved to be a homogenous species on the basis of ITS-sequences. Morphologically, Pseudallescheria and Petriella are distinguished by ostiolate vs non-ostiolate ascomata, a bipartition reflected also in ITS sequence data. We hypothesise a secondary loss of the ostiole of Pseudallescheria due to its ecological preferences. Infraspecific grouping within the highly variable species P. boydii is consistent for at least one clade in the ITS tree. The evolution of lineages with increased virulence within P. boydii is discussed.Mycological Research 03/2006; 110(Pt 2):151-60. · 2.81 Impact Factor
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ABSTRACT: The soils of five potted plants cultivated within a hospital were investigated for the presence of fungal opportunistic pathogens of humans. A total of 16 potentially pathogenic species were isolated, including Aspergillus fumigatus at up to 53.5 colony-forming units (CFU) per gram dry soil and Scedosporium apiospermum (Pseudallescheria boydii) at up to 97.0 CFU/g. Other common species included Phialophora verrucosa and Fusarium solani. Scedosporium inflatum, a recently described emerging pathogen, is reported for the first time from an environmental source. The results of this study, in combination with previous case reports linking mycoses to potted plants and available information on the establishment and dispersal of fungal opportunistic pathogens in indoor habitats, indicate that indoor plant soils constitute a serious mycotic hazard to the immunosuppressed patient.Mycopathologia 05/1989; 106(1):13-22. · 1.49 Impact Factor