EFFECT OF ETHYLENEDIAMINETETRAACETATE UPON SURFACE OF ESCHERICHIA-COLI
EFFECT OF ETHYLENEDIAMINETETRAACETATE UPON SURFACE OF ESCHERICHIA-COLI
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DOI：
10.1128/jb.130.3.1364-1381.1977
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发表时间：
1977-01-01
影响因子：
3.2
通讯作者：
LEIVE, L
中科院分区：
文献类型：
--
作者：
BAYER, ME;LEIVE, L
研究了EDTA对2株E.大肠杆菌（B和Cla）进行了研究。未处理的细胞显示外膜的外表面具有约4.5 nm直径的随机间隔凹陷的精细纹理;观察到结构表面元素对称排列的小区域。外膜的断裂面显示颗粒在其凹面上随机分布，仅偶尔被无颗粒区域中断。外膜断裂面的凸面仅显示少量分散的颗粒。内膜的分裂面经常被许多局部升高的平台所中断，在这些平台处，分裂过程在短距离内切换到外膜。EDTA处理的影响主要见于冷冻蚀刻的外膜的结构中：外膜外表面的凹坑和对称表面元素已经消失;观察到许多平台（约20-50个/细胞），在这些平台处，内膜内的分裂平面已经切换到外膜的疏水部分（外膜的断裂平面）。这些平台在未处理的细胞中可见; EDTA处理显然导致平台暴露增加。通过冷冻蚀刻暴露的表面区域揭示了作为细胞表面轮廓中的升高的底层平台，这表明相对于外膜的其余部分，平台区域中的蚀刻速率较慢。EDTA处理后，外膜断裂面（凹面）中边界清晰、无颗粒的斑块比对照组更常见且尺寸更大。在甘油存在下，细胞通常在外膜的断裂面裂开，但很少观察到孤立的平台。细胞在37 ℃代谢中毒15-25分钟后，C，高原变宽了。高原的物质可能有一个缓慢的横向扩散速率。将EDTA处理的细胞置于37 ℃新鲜培养基中。C引起，3-5分钟后，凹坑表面结构的重现。平台区代表局部区域，新合成的脂多糖可能插入其中。
The effect of EDTA on the envelope of 2 strains of E. coli (B and Cla) was studied with freeze-fracturing methods. Untreated cells showed the outer membrane''s outer surface with a fine texture of randomly spaced depressions of about 4.5 nm diameter; small areas with symmetrical arrangements of structural surface elements were observed. The outer membrane''s fracture plane revealed a random distribution of particles on its concave plane, only occasionally interrupted by particle-free areas. The convex aspect of the outer membrane''s fracture plane showed only a few scattered particles. The cleavage plane of the inner membrane was often interrupted by many localized elevated plateaus, at which the cleaving process had, for short distances, switched to the outer membrane. The effects of EDTA treatment were mainly seen in the structure of the freeze-etched outer membrane: the pits and the symmetrical surface elements of the outer membrane''s outer surface had disappeared; a number of plateaus (about 20-50/cell) were seen at which a cleavage plane within the inner membrane had switched to the hydrophobic portion of the outer membrane (outer membrane''s fracture plane). These plateaus were visible in untreated cells; EDTA treatment apparently caused an increased exposure of plateaus. Surface areas, exposed by freeze-etching, revealed the underlying plateaus as elevations in the surface contour of the cell, suggesting a slower etching rate in the zones of the plateaus relative to the rest of the outer membrane. Well-defined, particle-free patches in the outer membrane''s fracture plane, concave, were more frequent and larger in size after EDTA treatment than in the controls. In the presence of glycerol, the cells often cleaved in the outer membrane''s fracture plane, but isolated plateaus were rarely observed. After metabolic poisoning of cells for 15-25 min at 37.degree. C, the plateaus widened. The material of the plateaus probably has a slow rate of lateral diffusion. Placement of EDTA-treated cells in fresh medium at 37.degree. C caused, after 3-5 min, the reoccurrence of the pitted surface structure. The plateaus represent localized zones, at which newly synthesized lipopolysaccharide may be inserted.