猪链球菌谷氨酰胺tRNA合成酶的原核表达产物的小鼠免疫试验

【目的】猪链球菌谷氨酰tRNA合成酶(Glutamyl tRNA Synthetase,GtS)是一种催化谷氨酰胺与对应的tRNA发生酯化反应形成谷氨酰tRNA的蛋白酶。本研究通过小鼠免疫保护力实验来评价Gts的免疫原性。【方法与结果】使用clustalX对GenBank中链球菌属的GtS进行同源性分析,结果显示GtS的氨基酸序列在链球菌属内同源性达到95%以上。利用原核表达系统在大肠杆菌BL21中表达(His)6-GtS融合蛋白。SDS-PAGE和Western blot结果表明该融合蛋白在BL21菌株中高效表达,并且具有良好的免疫原性。融合蛋白经过组氨酸标签纯化试剂盒(Novagen)纯化后获得纯度为93.3%、浓度为433μg/mL的重组蛋白rGtS。在小鼠免疫保护试验中,使用rGtS混合弗氏佐剂免疫Balb/c小鼠。免疫过后用4倍LD50剂量的SC19菌株(1.2×109CFU)攻毒,rGtS免疫组小鼠的存活率达50%(4/8),高于空载体对照(1/8)。【结论】本研究证实rGtS融合蛋白具有良好免疫原性,能够提供部分的保护,是一种非常有潜力的亚单位疫苗候选蛋白。     

Ethanol Induces Sedation and Hypnosis via Inhibiting Histamine Release in Mice

Ethanol is one of the most highly abused psychoactive compounds worldwide and induces sedation and hypnosis. The histaminergic system is involved in the regulation of sleep/wake function and is a crucial player in promoting wakefulness. To explore the role and mechanism of the histaminergic system in ethanol-induced sedation and hypnosis, we recorded locomotor activity (LMA) and electroencephalography (EEG)/electromyography (EMG) in mice using an infrared ray passive sensor recording system and an EEG/EMG recording system, respectively, after administration of ethanol. In vivo microdialysis coupled with high performance liquid chromatography and fluorometry technology were used to detect histamine release in the mouse frontal cortex (FrCx). The results revealed that ethanol significantly suppressed LMA of histamine receptor 1 (H₁R)-knockout (KO) and wild-type (WT) mice in the range of 1.5–2.5 g/kg, but suppression was remarkably stronger in WT mice than in H₁R-KO mice. At 2.0 and 2.5 g/kg, ethanol remarkably increased non-rapid eye movement sleep and decreased wakefulness, respectively. Neurochemistry experimental data indicated that ethanol inhibited histamine release in the FrCx in a dose-dependent manner. These findings suggest that ethanol induces sedation and hypnosis via inhibiting histamine release in mice.

     

Sequential improvement of rimocidin production in Streptomyces rimosus M527 by introduction of cumulative drug-resistance mutations

Journal of Industrial Microbiology & Biotechnology - Rimocidin is a polyene macrolide that exhibits a strong inhibitory activity against a broad range of plant-pathogenic fungi. In this study,...