Functional analysis of motA gene in Azorhizobium caulinodans ORS571

[Objective] MotA,an important flagellar motor protein regulating flagellar motility,is one of components of transmembrane proton channel.In this study,we explored the role of motA in Azorhizobium caulinodans ORS571 in the free-living and symbiotic states.[Methods] DeltamotA mutant was constructed by homologous recombination and tri-parental conjugation.We tested the characterizations of the growth state,swimming motility,nitrogen fixation,exopolysaccharides (EPS) production,biofilm formation,and host colonization between wild-type and DeltamotA mutant.[Results] DeltamotA mutant showed defective cell motility ability but the growth property was not impaired,and its nitrogen fixation,EPS production,biofilm formation,and host colonization were lower than that of the wild-type.[Conclusion] In A.caulinodans ORS571,MotA plays role in motility,nitrogen fixation,EPS production,biofilm formation,and root colonization

4π探测器阵列实验的电子学与获取系统

介绍了 4 π多探测器阵列上的第一次中能重离子实验的电子学与数据获取系统。4 π多探测器为快慢塑料探测器和快塑料闪烁体 + Cs I的 Phoswich探测器组成 ,通过电荷数字转换 (QDC)分别记录探测器快慢信号 ,实现粒子的鉴别。在逻辑电路中 ,对前后角探测器分别给出 Trigger信号、QDC的清零信号和快慢公共门信号等。结果表明 ,前角探测器从质子、氘、氚、3 He、4He一直到 S、P等均可分

中能重离子碰撞中带电粒子多重性的同位旋效应

利用兰州4π带电粒子探测器阵列测量带电粒子多重性,研究了55MeV/u ~(40)Ar+~(58,64)Ni核反应中He和中等质量碎片的产额与反应系统同位旋的关系,以及这种同位旋效应与反应系统的碰撞参数(即碰撞的激烈程度)、系统的激发能的变化关系,对两个反应系统,观察到带电粒子多重性中He的比分随带电粒子多重性的增加而增大,带电粒子多重性中IMF的比分随带电粒子多重性的增加而先增大,后减小的规律.两个反应系统虽然具有相同的核电荷数,但轻粒子He和中等质量碎片在多重性中的比分有明显的同位旋相关性