SEPTUM FORMATION IN ESCHERICHIA-COLI - CHARACTERIZATION OF SEPTAL STRUCTURE AND EFFECTS OF ANTIBIOTICS ON CELL-DIVISION
SEPTUM FORMATION IN ESCHERICHIA-COLI - CHARACTERIZATION OF SEPTAL STRUCTURE AND EFFECTS OF ANTIBIOTICS ON CELL-DIVISION
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DOI：
10.1128/jb.119.1.303-324.1974
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发表时间：
1974-01-01
影响因子：
3.2
通讯作者：
MURRAY, RGE
中科院分区：
文献类型：
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作者：
BURDETT, IDJ;MURRAY, RGE
大肠杆菌B和B/r菌株经丙烯醛和戊二醛固定后的切片中可显示隔膜。隔膜由向内生长的细胞质膜和粘肽层组成;外膜被排除在隔膜之外，直到细胞开始分离。还观察到了介体。隔膜是高度不稳定的，除了在链形成菌株，E。coliD 22 envA和CRT 97，不易通过标准程序保存。隔膜的不稳定性可能是由于位于假定分裂部位的自溶素的存在。用氨苄青霉素（2 ~ 5 μg/ml）阻断E. coliB/r在细胞的中间产生一个凸起;凸起的形成被氯霉素阻止。头孢菌素也诱导隆起形成，但可能阻止细胞伸长以及分裂。当粘肽被修饰以允许隔膜的构建时，由于自溶素的假定作用而形成的隆起可能是隔膜序列中的初始步骤。在42 ℃时停止分裂的无隔菌形成菌株PAT 84中，只有在氨苄青霉素存在下，在30 ℃或42 ℃ NaCl（0.25 - 0.34M）存在下，在下移时才形成凸起。用氯霉素进行的实验表明，丝被完全区室化，但由于自溶素在42 ℃时失活而不是合成丧失而不能分裂。
Septa can be demonstrated in sections ofEscherichia colistrains B and B/r after fixation with acrolein and glutaraldehyde. The septum consists of an ingrowth of the cytoplasmic membrane and the mucopeptide layer; the outer membrane is excluded from the septum until the cells begin to separate. Mesosomes have also been observed. The septum is highly labile and, except in the chain-forming strains,E. coliD22envA and CRT 97, not easily preserved by standard procedures. The labile nature of the septum may be due to the presence of autolysin(s) located at the presumptive division site. Blocking division by addition of ampicillin (2 to 5 μg/ml) to cells ofE. coliB/r produces a bulge at the middle of the cells; bulge formation is stopped by addition of chloramphenicol. Cephalosporins also induce bulge formation but may stop cell elongation as well as division. Bulge formation, due to the presumed action of an autolysin(s), may be an initial step in the septation sequence when the mucopeptide is modified to allow construction of the septum. In a nonseptate filament-forming strain, PAT 84, which ceases to divide at 42 C, bulge formation only occurs in the presence of ampicillin at the time of a shift-down at 30 C or at 42 C in the presence of NaCl (0.25 to 0.34 M). Experiments with chloramphenicol suggest that the filaments are fully compartmentalized but fail to divide owing to the inactivation, rather than loss of synthesis, of an autolysin at 42 C.