ST酿酒酵母基因工程菌对大鼠肠道菌群的影响

为了研究ST酿酒酵母基因工程菌对大鼠肠道菌群的影响,试验将90只SPF级SD大鼠随机分为空白对照组、工程菌组及酵母菌组,分别灌服生理盐水、工程菌菌液、酿酒酵母菌菌液,持续21 d后连续3 d灌服大肠杆菌H10407菌液,分别收集灌胃7,14,21天及攻毒后的各组大鼠粪便,提取粪便细菌DNA,利用末端限制性片段长度多态性(T-RFLP)、实时荧光定量PCR检测了ST酿酒酵母基因工程菌对肠道菌群微生物可操作单元(OTU)和肠道5种重要细菌(类杆菌、梭菌、肠球菌、双歧杆菌和乳杆菌)数量的变化,并测定了肠道菌群pH值。结果表明:在灌胃期间,工程菌组及酵母菌组的OTU值和双歧杆菌、梭菌数量极显著高于空白对照组(P<0.01),其他细菌数量均不同程度升高。各组pH值均呈现下降趋势,第21天时,工程菌组及酵母菌组pH值极显著低于空白对照组(P<0.01)。攻毒产肠毒素大肠杆菌后,工程菌OTU值和类杆菌、乳杆菌、双歧杆菌数量均极显著高于其他两组(P<0.01),pH值极显著高于空白对照组(P<0.01)。与灌服前相比,工程菌组的OTU值、细菌数量及pH值均变化幅度最小。说明ST酿酒酵母基因工程菌能够改善肠道菌群结构,丰富肠道菌群多态性,降低pH值,增加有益菌群的数量。当动物机体受到产肠毒素大肠杆菌感染时,ST酿酒酵母基因工程菌能够有效降低产肠毒素大肠杆菌对肠道菌群的破坏,发挥预防保护作用,维持肠道内菌群稳定。

HAL1 mediate salt adaptation in Arabidopsis thaliana

The yeast HAL1 gene was introduced into Arabidopsis thaliana by Agrobacterium tumefaciens-mediated transformation with vacuum infiltration under the control of CaMV 35S promoter. Thirty-three individual kanamycin resistant plants were obtained from 75,000 seeds. Southern blotting analysis indicated that HAL1 gene had been integrated into all of the transgenic plants’ genomes. The copy number of HAL1 gene in transgenic plants was mostly 1 to 3 by Southern analysis. Phenotypes of transgenic plants have no differences with wild type plants. several samples of transformants were self-pollinated, and progenies from transformed and non-transformed plants (controls) were evaluated for salt tolerance and gene expression. Measurement of concentrations of intracellular K+ and Na+ showed that transgenic lines were able to retain less Na+ than that of the control under salt stress. Results from different tests indicated the expression of HAL1 gene promotes a higher level of salt tolerance in vivo in the transgenic Arabidopsis plants.