Influence On Phenotype And Ribosomal DNA Sequence Of Trichophytin Rubrum Resulting From Subcultured

Trichophytin rubrum is the commonest anthropophilic species in the Trichophytin genus ,80% of tinea unguium and 72% of tinea corporis caused by Trichophytin rubrum.. subcultur make phenotypes of strains to change easily,which brings difficulties for strain identification.It is significant to identify strains based on fungal genes.In recent years, substantial polymorphism in the ribosomal DNA (rDNA) nontranscribed-spacer region of T. rubrum is a hot topic for research..In our experiment,6 T. rubrum strains with different phenotypes were subcultured,from original strains to the twentith subcultured ones,we compared with the change of phenotypes after subcultured.And PCR was performed to amplify the 3'end of the 5.8S rDNA and the adjacent ITS2 region and two novel tandemly (TRS-1, TRS-2) in the DNA nontranscribed-spacer region from template DNA of the 6 T. rubrum strains and the twentith subcultured strains ,and gene sequencing,then we compared with the change of gene sequence with original strains and the twentith subcultured ones,therefore,we study on stability of ohenotype and genotype of Trichophytin rubrum after subcultured.Material and methods: One standard isolate was conserved in American Types Cultuer Collection (ATCC294),5 strains were isolated from clinical samples.The strains were identified to species level on the basis of colonial characteristics ,physiology and biochemics.All strains isolated recently were subcultured to the twenty times at an interval of fourteen days on Sabouraud agar slopes. PCR was performed using primer of fungal conservative region of ribosomal DNA and the adjacent ITS2 region(primer 1:5'-GCATCGATGAAGAACGCAGC -3',primer 2: 5'-TCCTCCGCTTATTGATATGC-3'), PCR was performed to amplify TRS-1 repeat units and TRS-2 repeat units respectively from template DNA of the 6 strains and the twentith subcultured strains by using primerTrNTSF-2(5'-ACCGTATTAAGCTAGCGCTGC-3'),TrNTSR-4(5'-TGCCACTT...