Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed p...Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed primers to amplify the Quinolone-resistance-determining region （QRDR） of gyrA and par（？,, then the PCR products were sequenced and analyzed. In comparision with NCTC5776, a single mutation was found at base 371 in gyrA of strain 38 which changed from C to T, and a single mutation was found at base 350 in gyrA of strain 60 which changed from A to C. No mutation was found in gyrA of the rest The mutation of strain 38 led to an amino acid substitution of Arg99Cys and the mutation of 60 led to an amino acid substitution of Met 92 Leu. No mutation was found in parC QRDR of all the isolates. These results indicats that the DNA gyrase will be the primary target to salmonella of fluoroquinolone.展开更多
有源极化雷达校准器(polarimetric active radar calibrator,PARC)以其高雷达散射截面以及高信杂噪比的优点,在雷达极化校准领域中受到了广泛的应用。针对PARC系统只能工作在固定频段和有限带宽内而在超宽带雷达极化校准中使用受限的问...有源极化雷达校准器(polarimetric active radar calibrator,PARC)以其高雷达散射截面以及高信杂噪比的优点,在雷达极化校准领域中受到了广泛的应用。针对PARC系统只能工作在固定频段和有限带宽内而在超宽带雷达极化校准中使用受限的问题,提出一种基于参数外推的超宽带雷达有源极化校准技术。利用谱估计方法将校准器对应频段的极化校准参数外推至其他频段,然后对相应频段进行处理,从而拓宽有源极化校准器的工作频带范围。利用工作频率为8~12 GHz的PARC对4~16 GHz全极化雷达进行校准,原始校准参数和外推校准参数在各自频段均取得良好的极化校准效果,证明了所提方法的有效性和工程实用价值。展开更多
文摘Nine strains resistant to five fluoroquinolones （Ciprofloxacin, Ofloxacin, Enrofloxacin, Danofloxacin, Sarafloxacin） were isolated from clinical samples and extracted the chromosomal DNA of these strains. Designed primers to amplify the Quinolone-resistance-determining region （QRDR） of gyrA and par（？,, then the PCR products were sequenced and analyzed. In comparision with NCTC5776, a single mutation was found at base 371 in gyrA of strain 38 which changed from C to T, and a single mutation was found at base 350 in gyrA of strain 60 which changed from A to C. No mutation was found in gyrA of the rest The mutation of strain 38 led to an amino acid substitution of Arg99Cys and the mutation of 60 led to an amino acid substitution of Met 92 Leu. No mutation was found in parC QRDR of all the isolates. These results indicats that the DNA gyrase will be the primary target to salmonella of fluoroquinolone.
