Comparative analysis of secreted enzymes between the anthropophilic-zoophilic sister species Trichophyton tonsurans and Trichophyton equinum.

Trichophyton tonsurans (TT) and Trichophyton equinum (TE) are two closely related dermatophytes with very different host preferences. This study was designed to examine the genetic and transcript level variations of secreted enzymes between TT and TE. Thirty-one genes representing 10 gene families were selected for comparison and complete genomic and cDNA sequences were elucidated. Sequence analyses of the selected genes identified 104 polymorphisms between the two dermatophytes, 37 of which are expected to encode changes in their polypeptide sequence. Quantitative RT-PCR was used to examine the differences in levels of transcript between TT and TE grown over 14d in aqueous keratin medium. Differences in transcript expression between TT and TE were gene specific and ranged from 1.1-fold to 33-fold. Intra-specific variability across all genes ranged from 41% to 250%. Despite their overall genetic similarity, TT and TE exhibit a moderate degree of variability in the genomic make-up of their secreted enzymes and the extent to which they are transcribed when grown in an aqueous keratin medium. Such differences may contribute to how these genetically similar organisms have adapted to infect divergent host organisms.

The prevalence of infections with Trichophyton tonsurans in schoolchildren: the CAPITIS study.

BACKGROUND: Although Trichophyton tonsurans has become the leading cause of tinea capitis in the United States, reported infection rates vary widely, and prevalence estimates for the pediatric population at large remain poorly characterized. METHODS: A prospective, cross-sectional, surveillance study of children attending kindergarten through fifth grade in 44 schools across the bi-state (Kansas/Missouri), Kansas City metropolitan area was conducted. Fungal cultures were collected from all participants, and molecular analyses were used to characterize the patterns of infection within the population. RESULTS: Of 10,514 children (age: 8.3 +/- 1.9 years) examined for the presence of T tonsurans on their scalps, 6.6% exhibited positive cultures. Infection rates at participating schools ranged from 0% to 19.4%, exceeding 30% at a given grade level in some schools. Black children demonstrated the highest rates of infection (12.9%), with prevalence estimates for the youngest members of this racial group approaching 18%. Infection rates for Hispanic (1.6%) and white (1.1%) children were markedly lower. A single genetic strain of T tonsurans was identified in only 16.6% of classrooms, whereas each child harbored a unique genetic strain in 51.4%. CONCLUSIONS: We report a large-scale, citywide, surveillance study of T tonsurans infection rates among children in primary school in a metropolitan area. The striking prevalence rates and genetic heterogeneity among the fungal isolates confirm the relatively large degree to which this pathogen has become integrated into metropolitan communities.

Clonal outbreak of Trichophyton tonsurans tinea capitis gladiatorum among wrestlers in Adana, Turkey.

Tinea capitis gladiatorum and tinea corporis gladiatorum caused by the anthropophilic dermatophyte Trichophyton tonsurans are well-known clinical entities in individuals involved in combat sports, e.g., wrestlers and judo practitioners. We present an outbreak of Trichophyton tonsurans tinea capitis gladiatorum among wrestlers at a boarding school in Adana, Turkey. Fourteen of the 29 wrestlers examined (48.3%) harbored the pathogen, including eight asymptomatic scalp carriers, five with tinea capitis superficialis, and one asymptomatic trunk carrier. Dermatophytes were isolated from samples of the neck (1), nape (1), trunk (3) and inguinal area (2) in four of the five tinea capitis cases. A total of five inanimate objects, i.e., two wrestling mats, two pillowcases, and one sheet were also found to be positive for T. tonsurans. Mixed-marker strain typing examining 24 sequence variations in 12 gene loci confirmed that the outbreak was caused by a single strain of T. tonsurans.

Regulation of the CYP3A4 and CYP3A7 promoters by members of the nuclear factor I transcription factor family.

Despite the established interindividual variability and ontogeny of the CYP3A enzymes, the most abundant phase I drug-metabolizing enzymes in human liver and intestine, the mechanisms that regulate basal expression remain poorly understood. Electrophoretic mobility shift assays using nuclear proteins extracted from human prenatal and postnatal liver samples identified multiple, developmentally distinct nuclear factor I (NFI)-containing protein complexes from human liver bound to sequences from the CYP3A4 (-243/-220) and CYP3A7 (-242/-219) proximal promoters. In addition, a hepatocyte nuclear factor (HNF) 3gamma-containing complex from prenatal liver interacted with CYP3A7-242/-219 but not CYP3A4-243/-220. Cotransfection of HepG2 cells with a CYP3A4 proximal promoter construct and expression vectors for the NFI isoforms NFIA1.1, NFIB2, NFIC1, NFIC2, and NFIX1 enhanced the expression of luciferase activity. In contrast, cotransfection of NFIB2, NFIC1, NFIC2, NFIX1, and NFIX2 reduced the expression of luciferase under the control of the CYP3A7 gene promoter. Mutagenesis of the NFI/HNF3gamma binding sites in the CYP3A7 and CYP3A4 proximal promoters suggests that regulation of basal promoter activity by members of the NFI transcription factor family occur via multiple mechanisms. These results demonstrate that members of the NFI transcription factor family regulate CYP3A4 and CYP3A7 basal expression in an isoform- and promoter-specific manner.

Drosophila doubletime mutations which either shorten or lengthen the period of circadian rhythms decrease the protein kinase activity of casein kinase I.

In both mammals and fruit flies, casein kinase I has been shown to regulate the circadian phosphorylation of the period protein (PER). This phosphorylation regulates the timing of PER's nuclear accumulation and decline, and it is necessary for the generation of circadian rhythms. In Drosophila melanogaster, mutations affecting a casein kinase I (CKI) ortholog called doubletime (dbt) can produce short or long periods. The effects of both a short-period (dbt(S)) and long-period (dbt(L)) mutation on DBT expression and biochemistry were analyzed. Immunoblot analysis of DBT in fly heads showed that both the dbt(S) and dbt(L) mutants express DBT at constant levels throughout the day. Glutathione S-transferase pull-down assays and coimmunoprecipitation of DBT and PER showed that wild-type DBT, DBT(S), and DBT(L) proteins can bind to PER equivalently and that these interactions are mediated by the evolutionarily conserved N-terminal part of DBT. However, both the dbt(S) and dbt(L) mutations reduced the CKI-7-sensitive kinase activity of an orthologous Xenopus laevis CKIdelta expressed in Escherichia coli. Moreover, expression of DBT in Drosophila S2 cells produced a CKI-7-sensitive kinase activity which was reduced by both the dbt(S) and dbt(L) mutations. Thus, lowered enzyme activity is associated with both short-period and long-period phenotypes.