Investigation of mutations in exons 12-15 MYH7 gene in hypertrophic cardiomyopathie patients using PCR-SSCP technique

Hypertrophic cardiomyopathy [HCM] is the most common kind of Mendelian inherited heart disease, affects 0.2% of the global population. HCM is also the most common cause of sudden cardiac death in individuals younger than 35 years old. To date more than 900 individual mutations has been identified in over 20 genes, such as MYH7, MYBPC3, and TNNT2. Interestingly, most of these genes encode sarcomeric proteins. In the present study, we investigated the possible presence of mutation in exons 12-15 MYH7 gene, which has already been reported to accommodate some mutations, in 30 patients with HCM in Chaharmahal va Bakhtiyari province. DNA was extracted using standard phenol-chloroform method and then was used for amplification and gel electroploresis by PCR-SSCP procedure. Finally, the suspected cases were selected for the direct sequencing and the results were analyzed using chromas software. There is no mutation in these exons, but two polymorphisms including: 5811 C>T and 5845 G> were found in the exon 12 of 1 and 5 separate patients, respectively. In this study with respect to none amino acid codon changes arisen from these polymorphisms, we concluded that mutations in these exons of MYH7 gene have a very low contribution in patients in this province and this is necessary to study other exons for better assessment

Study the expression of mar a gene in ciprofloxacin and tetracycline resistant mutants of esherichia coli

Mar A activates two membrane dependent mechanisms of resistance to different antibiotics, such as ciprofloxacin and tetracycline, including promotion of outflux and inhibition of influx of antibiotics. Thus, MarA causes multiple antibiotic resistance phenotype. The activation of these mechanisms needs overexpression of mar A. This could happen through mutation in marR. Thus, the aim of this study was to measure mar A expression in ciprofloxacin resistant E. coli gyrA mutants and clones with or without marR mutation. For this purpose, real time PCR was used to measure relative expression ofmarA in above mutants and clones. Results showed that two clones, C14 and C17 overexpressed mar A. It is concluded that the level of mar A expression is important for activation of above mechanisms

Study of organic solvent tolerance and increased antibiotic resistance properties in E. coli gyrA Mutants

Ciprofloxacin is one of the most widely used antibiotics for the treatment of several infections caused by Gram-negative bacteria, like E. coli. Changes in gyrA, encoding GyrA subunit of DNA gyrase, cause the resistance to ciprofloxacin. Some ciprofloxacin resistant gyrA mutants acquired constitutive expression of marRAB operon due to the gaining mutations in marR, a repressor of this operon. This leads to the expression of a multidrug resistance phenotype and high organic solvent tolerance. Thus, this study was aimed to provide more information on extra mechanisms of resistance in gyrA mutants with different ciprofloxacin MICs. For this purpose, the tolerance of organic solvent, resistance to tetracycline and presence of possible mutation in marOR were investigated in 10 gyrA mutants. Results showed that most of gyrA mutants behaved like MG1655, control strain, but 3 out of 10 were slightly more resistant to tetracycline than MG1655 and had better growth on hexane. Among three mutants, two possess a mutation in marOR. In conclusion, the generation of mutation in marOR is not enough by itself to produce the multidrug resistance phenotype and complete activation of AcrAB-TolC