ABSTRACT
To re-identify and further group 25 isolates of Trichosporon spp. identified morphologically previously, sequences of D1/D2 region of large subunit (LSU) of ribosomal DNA (rDNA) of 25 tested strains for identification and those of ribosomal intergenic space 1 (IGS1) region of 11 strains for subgrouping were detected. The identifications of tested strains were changed except 6 strains. According to the alignment of the IGS1 region, 6 T. asahii isolates tested fell into 4 groups and 5 T. faecale isolates into 3 groups. Polymorphism of 2 T. japonicum isolates was found in 10 positions. With the alignments obtained in this research compared with the relative GenBank entries, it was found that T. asahii, T. faecale and T. japonicum species were divided into 7, 3 and 2 subtypes respectively. Morphological and biophysical methods are not sufficient for Trichosporon spp. identification. Sequencing becomes necessary for Trichosporon diagnosis. There is obvious diversity within a species.
ABSTRACT
Various oxidases and hydrolytic enzymes were analyzed to investigate the relationship between these enzymes and the skin pathogenicity of 18 Mucorales strains. Each strain was cultured in a nutrient medium containing starch as a carbon source. The cells grew quickly and were at a good state of growth after incubation for three days. Oxidase activity was not detected in any strain, whereas Mucor spp. including Mucor racemosus IFM47053 typically had high alcohol dehydrogenase (ADH) activity and all the strains had catalase activity. The culture filtrate and the cell free extract of each strain were applied to APIZYM test system, which revealed that all the strains examined produced many hydrolytic enzymes both inside and outside their mycelia. In the case of Absidia corymbifera strains, lipase activity was comparatively high, and polysaccharide hydrolytic enzymes such as alpha-glucosidase, beta-glucosidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and alpha-fucosidase were produced.
Subject(s)
Absidia , Alcohol Dehydrogenase , alpha-Glucosidases , alpha-L-Fucosidase , alpha-Mannosidase , beta-Glucosidase , Carbon , Catalase , Hydrolases , Lipase , Mucor , Mucorales , Oxidoreductases , Skin , Starch , Virulence , ZygomycosisABSTRACT
Objective To report a case of chromomycosis caused by Phialophora verrucosa and explore the laboratory features of the pathogen. Methods Skin lesion was examined by histopathology and fungus culture. The morphology of the isolate was observed by microscopy and scanning electron microscopy. The coenzyme Q system of this isolate was analyzed by HPLC assay. The DNA sequences of LSU rDNA D1/D2 region of this isolate and a standard fungus strain were compared. Results The initial lesion was an erythematous papule that subsequently developed into one or multiple coalescing warty papules or plaques slowly. The bronze-colored spores could were observed in the dermis or macrophages. The isolate grew very slowly, requiring 4 weeks of incubation. Microscopically, no characteristic structures were found on Sabourand′s dextrose agar, while there were vase-like structures, which were referred to as phialides on potato dextrose agar (PDA) and corn meal agar I (CMA-I). The phialides on PDA mostly grew at the top of hypha, but on CMA-I they mostly grew on the side of hypha. The isolate contained coenzyme Q-10, and its DNA sequence of LSU rDNA D1/D2 region completely consistent with those of the standard strain. Conclusion Chromomycosis caused by Phialophora verrucosa is rare in China. It can be diagnosed by fungus culture and histopathological examination. Coenzyme Q system analysis and DNA sequencing can exclude the interference from different phenotypes.