Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated a recently described linear signal amplification method for sensitivity and specificity in detecting mutations associated with resistance to rifampin (RIF) and isoniazid (INH) in Mycobacterium tuberculosis. The assay utilizes the thermostable flap endonuclease Cleavase VIII, derived from Archaeoglobus fulgidus, which cleaves a structure formed by the hybridization of two overlapping oligonucleotide probes to a target nucleic acid strand. This method, termed the Invader assay, can discriminate single-base differences. Nine pairs of probes, encompassing five mutations in rpoB and katG that are associated with resistance to either RIF or INH, as well as the corresponding wild-type (drug-susceptible) alleles, were tested using amplified DNA. Fluorescent-labeled cleavage products, ranging from 4 to 13 nucleotides in length, depending on the genotype of the test sample, were separated by denaturing polyacrylamide (20 to 24%) gel electrophoresis and then detected by scanning. All nine alleles could be identified and differentiated on the basis of product size. Multiple mutations at a specific rpoB nucleotide in target PCR products could be identified, as could mutants that were present at > or =0.5% of the total population of target sequences. The Invader assay is a sensitive screen for some mutations associated with antituberculosis drug resistance in amplified gene regions.
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PMID:Evaluation of the invader assay, a linear signal amplification method, for identification of mutations associated with resistance to rifampin and isoniazid in Mycobacterium tuberculosis. 1077 Jul 65

A mutation (CCG-->CTG [Arg-->Leu]) in codon 463 of katG (catalase peroxidase) of Mycobacterium tuberculosis has been found in isoniazid (INH)-resistant strains. A PCR restriction endonuclease analysis to detect this mutation was applied to 395 M. tuberculosis isolates from patients in The Netherlands. The proportion of isolates with a detectable mutation was 32% (32 out of 100) and 29% (85 out of 295) among INH-susceptible isolates and INH-resistant or -intermediate isolates, respectively. Sequencing of five INH-susceptible isolates with such mutations showed that all five had the Arg463Leu mutation. We conclude that the Arg463Leu mutation of katG of M. tuberculosis is not a reliable indicator of INH resistance.
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PMID:The susceptibility of Mycobacterium tuberculosis to isoniazid and the Arg-->Leu mutation at codon 463 of katG are not associated. 1128 93

In the present study, among 327 Mycobacterium tuberculosis (MTB) isolates collected from patients attending three different centres of North India, we attempted to find out the most common mutations occurring both at the Ser315 codon of katG and at the regulatory region of the mabA-inhA operon to evaluate their role for INH drug resistance in India. Out of 121 phenotypically INH-resistant MTB isolates, 88 (72.7%) were resistant to INH by genotypic methods viz., PCR-RFLP with MspI and SatI digestion and multiplex-PCR. PCR-RFLP results showed that 67 (55.4%) isolates had mutation in codon 315 of katG by SatI endonuclease. Among these, eight isolates that were found resistant by SatI PCR-RFLP were found to be sensitive by MspI PCR-RFLP. By multiplex-PCR we found 49 (40.5%), 21 (17.4%) and 10 (8.3%) isolates having AGC-->ACC substitution in katG only, mutation in inhA(C-15T) only and mutation in both respectively. Simultaneous use of both PCR-RFLP and multiplex-PCR can improve the detection rate of INH-resistant strains and may have an advantage over the liquid culture system of detecting drug resistance. These findings also enhanced our understanding about potential of resistance-related mutations in M. tuberculosis clinical isolates in India and could help in development and designing of molecular methods for revealing the drug susceptibility profiles of M. tuberculosis clinical isolates.
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PMID:Molecular characterization of INH-resistant Mycobacterium tuberculosis isolates by PCR-RFLP and multiplex-PCR in North India. 1978 22