Molecular phylogeny and taxonomy of medically important fungi

Some recent advances in study of molecular evolution and taxonomy of human pathogens are discussed. In systemic Onygenales as well as in Chaetothyriales, pathogenic species are phylogenetically intermingled with non-pathogenic taxa. When a teleomorph of Coccidioides immitis is eventually found, it is predicted to resemble Uncinocarpus, a genus otherwise comprising environmental species. In the dermatophytes, Trichophyton and Microsporum are paraphyletic, whereas Epidermophyton is polyphyletic. On the basis of 18S and ITS rDNA sequencing data, Exophiala anamorphs (black yeasts) are confirmed to be closely related to the ascomycete genus Capronia. The related neurotropic species Cladophialophora bantiana is remarkable in consistently having introns in its 18S rDNA gene.

Molecular diagnostics of clinical strains of filamentous Basidiomycetes

Eleven clinical and veterinary strains of filamentous Basidiomycetes were compared with 15 reference strains representing the orders Aphyllophorales and Agaricales. The methods used were restriction analysis of small subunit (18S) (SSU) rDNA and internal transcribed spacers (ITS) 1 and 2 and variable domain 9 (V9)-ITS1 sequencing. Six strains were found to belong to the teleomorph genera Schizophyllum or Coprinus, whereas five could not be identified unequivocally. A rapid diagnostic overview is obtained with HaeIII and HinfI digestion of the ITS region.

Nutritional physiology and taxonomy of human-pathogenic Cladosporium-Xylohypha species

Physiological profiles of type, authentic and some additional isolates of Cladosporium-Xylohypha species of purported herpotrichiellaceous relationship are established. This group comprises melanized catenate hyphomycetes which are prevalently found on the human host. The species are excluded from the genus Cladosporium and are classified in the genus Cladophialophora. Taeniolella boppii is also transferred to this genus. Cladosporium bantianum (= Xylohypha emmonsii) and C. trichoides are considered conspecific and are now referred to as Cladophialophora bantiana. Meso-erythritol, L-arabinitol, ethanol and growth at 40 degrees C are found to be the most useful criteria for species distinction. The species Cladosporium carrionii is found to be heterogeneous. The anamorph of the saprophytic ascomycete Capronia pilosella is morphologically similar to an authentic strain of Cladosporium carrionii, but physiologically distinct. A diagnostic key for the recognized Cladophialophora species and to morphologically similar taxa is provided.

Nutritional pattern and eco-physiology of Hortaea werneckii, agent of human tinea nigra

The life cycle of Hortaea werneckii includes yeast-like, hyphal and meristematic growth. The preponderance of each form of propagation can be influenced by environmental conditions. The clinical entity 'tinea nigra' is explained by ecological similarities between supposed natural niches and human hyperhydrotic skin. The species is recognizable by assimilation of lactose, nitrate and nitrite, no or little growth with L-lysine, cadaverine, creatine and creatinine, and tolerance of 10% NaCl. It generally does not grow at 36 degrees C.