Assuntos
Genoma/genética , Mycobacterium leprae/genética , Animais , Povo Asiático , Genes Bacterianos , Humanos , Hansenostáticos/uso terapêutico , Camundongos , Camundongos Nus , Testes de Sensibilidade Microbiana , Mycobacterium leprae/classificação , Mycobacterium leprae/efeitos dos fármacos , Mycobacterium leprae/crescimento & desenvolvimento , Polimorfismo de Nucleotídeo Único/genética , Sequências de Repetição em Tandem/genética , TailândiaRESUMO
Simple sequence repeats (SSRs) are omnipresent in prokaryotes and eukaryotes, and are found anywhere in the genome in both protein encoding and noncoding regions. In present study the whole genome sequences of seven chromosomes (Shigella flexneri 2a str301 and 2457T, Shigella sonnei, Escherichia coli k12, Mycobacterium tuberculosis, Mycobacterium leprae and Staphylococcus saprophyticus) have downloaded from the GenBank database for identifying abundance, distribution and composition of SSRs and also to determine difference between the tandem repeats in real genome and randomness genome (using sequence shuffling tool) of the organisms included in this study. The data obtained in the present study show that: (i) tandem repeats are widely distributed throughout the genomes; (ii) SSRs are differentially distributed among coding and noncoding regions in investigated Shigella genomes; (iii) total frequency of SSRs in noncoding regions are higher than coding regions; (iv) in all investigated chromosomes ratio of Trinucleotide SSRs in real genomes are much higher than randomness genomes and Di nucleotide SSRs are lower; (v) Ratio of total and mononucleotide SSRs in real genome is higher than randomness genomes in E. coli K12, S. flexneri str 301 and S. saprophyticus, while it is lower in S. flexneri str 2457T, S.sonnei and M. tuberculosis and it is approximately same in M. leprae; (vi) frequency of codon repetitions are vary considerably depending on the type of encoded amino acids.
Assuntos
Sequência Rica em At/genética , Sequência Rica em GC/genética , Genoma Bacteriano/genética , Sequências Repetitivas de Ácido Nucleico/genética , Shigella flexneri/genética , Shigella sonnei/genética , Bactérias/genética , Nucleotídeos/genética , Sequências de Repetição em Tandem/genéticaRESUMO
Mycobacterium leprae isolates from Thai leprosy patients were typed for strain differentiation and analysis of leprosy transmission using the six base tandem repeat, GACATC, in rpoT gene and TTC repeat as genetic markers. M. leprae DNA was isolated from skin biopsies of new untreated leprosy patients living in remote areas or in suburban regions of Thailand where leprosy is in low prevalence. In M. leprae strains of 100 patients, TTC alleles exhibited variations in length with 10 to 30, 33 and 35 repeats, the most common alleles being 15, 16, 17 and 19 repeats. All isolates contained three copies of the six base repeat in rpoT gene. Application of TTC repeats in tracking leprosy transmission in two families with multi-cases identified a single (but different) strain of M. leprae in each family.
Assuntos
DNA Bacteriano/genética , Genes Bacterianos/genética , Hanseníase/microbiologia , Mycobacterium leprae/genética , Polimorfismo Genético/genética , Sequências de Repetição em Tandem/genética , Biópsia , Humanos , Hanseníase/transmissão , Mycobacterium leprae/classificação , Mycobacterium leprae/isolamento & purificação , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Pele , TailândiaRESUMO
This study has been carried out to get understanding of the origin among the strains of Mycobacterium leprae in patients from Northern India by using number of tandem repeats in rpoT gene as marker. Biopsies were collected from hundred leprosy cases (paucibacillary (PB) as well as multibacillary (MB)) across the spectrum from patients attending clinic at JALMA or diagnosed in Field Unit at Ghatampur (Kanpur). These biopsies were homogenized and DNA was extracted by a physiochemical procedure. rpoT region was amplified by using the primers and conditions earlier published. Among 100 strains from Northern Indian patients, 89% exhibited the presence of three copies of the 6bp tandem repeat in the rpoT gene, while 11% contained four copies. These profiles along with other genotyping data may help in studying the historical spread of leprosy by strains of M. leprae disseminated by various human races that migrated to Northern India from other places of Asian continent.
Assuntos
Proteínas de Bactérias/genética , Mycobacterium leprae/genética , Fator sigma/genética , Sequências de Repetição em Tandem/genética , Genótipo , Humanos , Índia , Hanseníase/microbiologiaRESUMO
A recent advance in molecular typing for tracing the transmission of leprosy is the discovery of short tandem repeats (STRs) in Mycobacterium leprae. To substantiate polymorphic loci from STR as promising candidates for molecular typing tools in leprosy epidemiology, 44 STR loci including 33 microsatellites and 11 minisatellites were investigated among 27 laboratory strains by sequencing PCR products. Not all STRs were necessarily polymorphic. Thirty-two out of the 44 loci were polymorphic. Nine polymorphic loci were suitable for identifying genotypes according to the discriminatory capacity, stability, and reproducibility. All the strains were classified into independent genotypes by the selected nine loci. Three multi-case households were subjected to molecular typing. M. leprae obtained from household cases showed identical copy numbers by TTC triplet alone, but the isolates from one family contact case were divided into different genotypes by adding eight other polymorphic loci. The combination of information from multiple loci allows increasing levels of discrimination and it is likely that the generation and documentation of data will result in the choice of a potential molecular typing tool for leprosy epidemiology.