Classification and Typing of Trichophyton mentagrophytes Isolated from a Korean Population / 대한의진균학회지

BACKGROUND: Trichophyton mentagrophytes complex is a heterogeneous group. A new classification, based on molecular biology, has replaced the one based on morphology, physiology, and mating behavior. OBJECTIVE: T. mentagrophytes isolates from Korean patients were classified using the new method and compared with the classic classification. METHODS: During 2010-2011, fungal isolates were collected at the Catholic skin clinic from 562 patients infected with T. mentagrophytes; clinical characteristics were reviewed. Patients were divided into four groups based on the morphological characteristics of the isolates. Thirty-four strains of T. mentagrophytes were randomly selected from the four groups for mycological and molecular biology analyses, including analyses of morphological characteristics, ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequence, and rDNA nontranscribed spacer (NTS) typing. RESULTS: Among the 562 isolates, persicolor (41.6%) was the most common strain type, followed by the powdery (38.4%), downy (11.2%), and granular (8.7%) types. The granular type differed from the other three with respect to the isolation site, patient's age, seasonal variation, and microscopic characteristics. Among the selected 34 strains, the microscopic characteristics varied for each strain. The powdery, persicolor, and downy types had ITS sequences identical to those of the anthropophilic T. interdigitale/A. vanbreuseghemii. The ITS sequence of granular type was similar to that of zoophilic T. interdigitale/A. vanbreuseghemii. The granular type had different NTS types than the other types did. CONCLUSION: The T. mentagrophytes strains isolated were classified as T. interdigitale/A. vanbreuseghemii; the majority (91.7%) was anthropophilic and 8.3% were zoophilic and granular type.

Molecular variability in Brycon cf. pesu Müller and Troschel, 1845 (Characiformes: Characidae) from the Araguaia-Tocantins basin

Brycon pesu is a small-sized fish distributed throughout the Amazon and Orinoco Basins and other coastal basins of northeastern South America. Brycon cf. pesu specimens from the Araguaia-Tocantins Basin are currently separated into two morphotypes, Brycon sp1 and Brycon sp2, owing to different coloration of their anal fin. Brycon sp2 has a reddish margin stripe on the anal fin which morphologically distinguishes it from Brycon sp1. In the present research, nuclear and mitochondrial markers were used to test the hypothesis that the Brycon sp1 and Brycon sp2 morphotypes are distinct species. Specimens from the two morphotypes were collected from the Lajeado Hydroelectric Plant and the Palmas River in the Araguaia-Tocantins Basin. Thirty-five loci obtained by the amplification of five inter-simple sequence repeat primers were analyzed but no species-specific bands were detected. Electrophoretic profiles obtained from 5S rDNA non-transcribed spacer amplification failed to show any differentiation in morphotypes. These results were corroborated by nucleotide sequence analysis of the mtDNA control region, in which 24 polymorphic nucleotide sites, representing a polymorphism rate of only 5%, were detected. The low rates of polymorphism detected by inter-simple sequence repeat, non-transcribed spacer and mtDNA D-loop markers strongly reject the hypothesis that the two morphotypes Brycon sp1 and Brycon sp2 represent distinct species within Brycon cf. pesu. Further studies are needed to obtain conclusive data on the notion that the coloration of the anal fin is an intraspecific polymorphism, possibly related to environmental factors.

Identification and Subtyping of Trichophyton rubrum by Molecular Biological Methods / 대한의진균학회지

BACKGROUND: Trichophyton rubrum is one of the major pathogens causing dermatophytoses on human. The identification of this species by mycological methods are sometimes difficult and time-consuming. Moreover, suitable methods for subtyping of this species are not established yet. OBJECTIVE: This study was performed to identify and subtype T. rubrum by molecular biological methods. METHODS: Total 65 clinical isolates of T. rubrum were included and classified according to the results of 8 mycological tests. Their identification were done by random amplified polymorphic DNA (RAPD) analysis. Subtyping of this species was performed by analyzing the DNA band patterns produced by amplifying the non-transcribed spacer (NTS) area of ribosomal DNA. RESULTS: The 65 strains of T. rubrum could be classified into 5 phenotypic varieties according to the results of mycological tests. All clinical isolates produced identical band pattern with those of standard strains of T. rubrum by RAPD analysis. Amplification of NTS area produced 13 PCR patterns. CONCLUSION: The confirmative identification of T. rubrum could be done by RAPD analysis regardless of their phenotypic variations. Subtyping of T. rubrum was successfully performed by amplifying NTS area but these PCR patterns were not correlated with their phenotypic characteristics.