Microbiology Section, Division of Biology, Kansas State University, Manhattan, Kansas 66506.
Appl Environ Microbiol. 1979 Dec;38(6):1173-8. doi: 10.1128/aem.38.6.1173-1178.1979.
Rhizobium trifolii 0403 maintained in exponential phase via periodic dilution doubled in 210 min in mannitol-salts medium and doubled in 244 min in glycerolsalts. In both media, cell number and optical density increased in parallel. When exponentially growing cells in either medium were supplemented with a mixture of glucose, Casamino Acids, succinate, and yeast extract, optical density continued to increase but within less than the time required for one doubling, division ceased. The increase in optical density coupled with division cessation resulted in the formation of large, pleomorphic, nondividing cells. Large cells apparently increased in size as a result of swelling only at regions of most recent cell envelope synthesis. Greater than 95% of the cells in a population swelled, and commitment to swelling occurred within two doubling time equivalents. Swollen cells eventually reached a characteristic maximum size and exhibited osmotic fragility.
苜蓿中华根瘤菌 0403 在指数生长期通过周期性稀释，在甘露醇盐培养基中倍增时间为 210 分钟，在甘油盐培养基中倍增时间为 244 分钟。在这两种培养基中，细胞数量和光密度都呈平行增长。当两种培养基中的指数生长期细胞补充葡萄糖、氨基酸、琥珀酸盐和酵母提取物的混合物时，光密度继续增加，但不到一个倍增所需的时间，细胞分裂就停止了。光密度的增加加上分裂的停止导致形成了大的、多形的、不分裂的细胞。大细胞显然是由于最近的细胞壁合成区域的肿胀而增大的。在一个群体中，超过 95%的细胞膨胀，并且在两个倍增时间当量内就开始膨胀。膨胀的细胞最终达到一个特征性的最大大小，并表现出渗透脆性。
