Rapid detection of Macrobrachium rosenbergii nodavirus isolated in China by a reverse-transcription loop-mediated isothermal amplification assay combined with a lateral flow dipstick method / 病毒学报

White coloration of the muscle of the giant river prawn (Macrobrachium rosenbergii) is a serious problem in China. The Macrobrachium rosenbergii Nodavirus (MrNV) has been confirmed to be the pathogen that causes this disorder. To develop a rapid, sensitive and specific technology for the detection of Macrobrachium rosenbergii Nodavirus isolated from China (MrNV-China), a reverse-transcription loop- mediated isothermal amplification assay combined with a lateral flow dipstick (RT-LAMP-LFD) assay method is described. A set of four primers and a labeled probe were designed specifically to recognize six distinct regions of the MrNV RNA2 gene. Results showed the sensitivity of the RT-LAMP-LFD assay was ten-times higher than the reverse-transcription loop-mediated isothermal amplification assay (RT-LAMP) with agarose gel electrophoresis. The assay was conducted with one-step amplification at 61°C in a single tube within 45 min. No product was generated from shrimps infected with other viruses, including DNA viruses (infectious hypodermal and hematopoietic necrosis virus (IHHNV); white spot syndrome virus (WSSV)) and RNA viruses (Taura syndrome virus (TSV); infectious myonecrosis virus (IMNV); yellow head virus (YHV)). Results were visualized by the LFD method. Therefore, the described rapid and sensitive assay is potentially useful for MrNV detection.

Study on the Optimum Culture for Growth of Bacillus Subtilis B115 andthe Antibacterial Effect of B115 on Aeromonas / 微生物学通报

The essential medium of B115 composed of 1% tryptone, 0.25% yeast extract and 0.5% sodium chloride was determined by using an orthogonal design. The orthogonal design was also employed in testing the optimum additions. It was composed of 0.1%(NH_(4))_(2)SO_(4),1.4%K_(2)HPO_(4), 0.6% KH_(2)PO_(4) and 0.1% (Na_(3)C_(6)H_(5)O_(7)). The yield of B115 cultured in optimum medium was compared with the one in essential medium. Statistic analysis showed that the growth of B115 was most significantly improved by adding K~(+)、NH~+_(4) and (Na_(3)C_(6)H_(5)O_(7)) to essential medium. The antibacterial effect of Bacillus subtilis strain B115 on pathogenic Aeromonas was studied. The results showed different antibacterial effects of B115 on different aeromonads. There were obvious antibacterial effects on BSK-10 and CL990920, while no effect on the growth of TL970424.