...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >A change in a single gene of Salmonella typhimurium can dramatically change its buoyant density.
【24h】

A change in a single gene of Salmonella typhimurium can dramatically change its buoyant density.

机译：鼠伤寒沙门氏菌单个基因的改变可以极大地改变其浮力密度。

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The growth rates and buoyant densities of a Salmonella typhimurium mutant, TL126 (proB74A+), with enhanced osmotolerance caused by proline overproduction were measured and compared with the growth rates and buoyant densities of an isogenic (wild-type) strain, TL128 (proB+ A+), with normal control of proline production. Growth rates were determined in a rich medium (Luria broth) with added NaCl to produce various osmotic strengths ranging from 300 to 2,000 mosM. At low concentrations of NaCl, there was little variation in doubling times between the two strains. However, as the osmotic strength of the medium approached and exceeded 1,300 mosM, the doubling times of TL126 (osmotolerant) were 1.5 to 2 times faster than those of TL128 (wild type), confirming the osmotolerance of TL126. Buoyant densities were determined by equilibrium sedimentation in a Percoll gradient of osmotic strength equal to that of the growth medium. The osmolarity of the Percoll gradient was adjusted by the addition of NaCl. At low osmolarities (300 to 500 mosM), the buoyant density of TL126 (osmotolerant) was slightly but consistently lower than that of TL128 (wild type). As the osmotic strength was increased, the buoyant density of TL126 (osmotolerant) increased in proportion to the osmotic strength. In contrast, the buoyant density of strain TL128 (wild type) did not increase as much. At high osmolarities (1,600 to 2,000 mosM), the buoyant density of TL126 (osmotolerant) was consistently higher than that of TL128 (wild type). These results suggest that the intracellular accumulation of proline by TL126, the osmotolerant strain, increases both the growth rates and buoyant densities at osmolarities of 1,300 mosM and above.
机译：测量了由脯氨酸过量生产引起的渗透压增强的鼠伤寒沙门氏菌突变体TL126（proB74A +）的生长速率和浮力密度，并将其与同基因（野生型）菌株TL128（proB + A +）的生长速率和浮力密度进行比较，正常控制脯氨酸的生产。在添加了NaCl的丰富培养基（Luria肉汤）中确定生长速率，以产生300到2,000 mosM的各种渗透强度。在低浓度的氯化钠下，两个菌株之间的倍增时间几乎没有变化。但是，随着培养基的渗透强度接近并超过1300 mosM，TL126（耐渗透性）的倍增时间比TL128（野生型）的倍增速度快1.5至2倍，这证明了TL126的耐渗透性。浮力密度是通过平衡沉降在渗透强度的Percoll梯度等于生长培养基的渗透率中确定的。通过加入NaCl调节Percoll梯度的渗透压。在低渗透压（300至500 mosM）下，TL126（耐渗透性）的浮力密度略低于但始终低于TL128（野生型）的浮力密度。随着渗透强度的增加，TL126（耐渗透性）的浮力密度与渗透强度成正比。相反，菌株TL128（野生型）的浮力密度没有增加太多。在高渗透压下（1600至2,000 mosM），TL126（耐渗透性）的浮力密度始终高于TL128（野生型）的浮力密度。这些结果表明，渗透容性菌株TL126在细胞内的脯氨酸积累，在渗透压为1,300 mosM及以上时，既提高了生长速度，又提高了浮力密度。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号