18S-rDNA SEQUENCING, ENZYME PATTERNS AND MORPHOLOGICAL CHARACTERIZATION OF TRICHOPHYTON ISOLATES

Abstract

Dermatophytes, capable to use keratin of the host for nutrition, belong to one of the major groups of pathogenic fungi. Since dermatophytes are a closely related group they share various common features, and the morphology of isolates of a given species can be atypical, making species identification and differentiation even more difficult. Many methods have been explored in attempts to distinguish dermatophytes, but the combined use of different approaches for the investigation of the intraspecific and interspecific variability of Trichophyton continues to be scarce. Some studies have shown that amplified fragments of the small ribosomal DNA subunit 18S contains variable regions which can be used to discriminate between medically relevant yeast species, indicating that these regions could also be used for differentiation between dermatophytes. In our study, sequence analysis of the 18S-rDNA gene was combined with morphological and biochemical criteria in order to detect genetic differences between seven Trichophyton isolates and estimate their phylogenetic relationships. The results show that the isolates investigated belong to the Trichophyton group, which potentially contains the Trichophyton rubrum cluster.

Electrophoretic molecular karyotype of the dermatophyte Trichophyton rubrum

“…CHEF analysis is useful in fungal epidemiological studies, and has revealed interand intraspecies variations in Candida infections (Pittet et al, 1991). The genetic variability of T. rubrum isolates has been demonstrated by sequence analysis of the 18S rDNA gene combined with morphological and enzymatic analysis (Nascimento and Martinez-Rossi, 2001).…”

Análise da expressão gênica no dermatófito Trichophyton rubrum mimetizando a infecção in vitro: pH e diferentes fontes de carbono regulando genes

“…DNA mitocondrial e do número de repetições da região espaçadora não transcrita (ITS) do RNA ribossômico (Kano et al, 1997;Kano et al, 2000;Nascimento & Martinez-Rossi, 2001 (Chermette et al, 2008;Seebacher et al, 2008), sendo a espécie mais prevalente deste gênero e o dermatófito mais comumente encontrado em lesões superficiais de pele e unha (Costa et al, 2002;Zahra et al, 2003). Mas apesar de ser considerado cosmopolita, o T.…”