SHAPE AND FINE-STRUCTURE OF NUCLEOIDS OBSERVED ON SECTIONS OF ULTRARAPIDLY FROZEN AND CRYOSUBSTITUTED BACTERIA
SHAPE AND FINE-STRUCTURE OF NUCLEOIDS OBSERVED ON SECTIONS OF ULTRARAPIDLY FROZEN AND CRYOSUBSTITUTED BACTERIA
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DOI：
10.1128/jb.162.3.960-971.1985
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发表时间：
1985-01-01
影响因子：
3.2
通讯作者：
KELLENBERGER, E
中科院分区：
文献类型：
--
作者：
HOBOT, JA;VILLIGER, W;KELLENBERGER, E
将大肠杆菌和枯草芽孢杆菌的快速冷冻细胞在低温下用含1%OsO_4的丙酮代替，并包埋在Epon中。它们显示无核糖体的空间充满了高达6至15 nm的球状和纤维状物质。所见结构的大小不排除DNA超结构，如超螺旋，聚集体和核小体。用Feulgen类似物锇-氨染色，DNA定位在无核糖体的空间内。因此，DNA的主体，即类核，是主要的无核糖体空间的主要部分，或者与主要的无核糖体空间相同。无核糖体的空间将直接对应于活细菌中类核的光学显微镜相差图像。核糖体自由空间的形状并不反映细胞内盐浓度，也不Feulgen阳性区域。先前观察到的对生长培养基的盐浓度的依赖性似乎是由于在室温下由化学固定剂诱导的透化作用。 无核糖体空间在外观上比用OsO 4固定获得的类核更分裂，但比醛固定后发现的非常分散的形式更局限。
Very rapidly frozen cells of Escherichia coli and Bacillus subtilis were substituted at low temperature into acetone with 1% OsO4 and embedded in Epon. They showed ribosome-free spaces filled with globular and fibrillar material of up 6 to 15 nm. The sizes of structures seen do not exclude DNA superstructures such as supercoils, aggregates and nucleosomes. With the Feulgen analog osmium-ammines stain, DNA was localized within the ribosome-free space. The bulk of DNA, the nucleoid, is therefore a major part of, or identical to, the main ribosome-free space. The ribosome-free space would correspond directly to the light microscopy phase-contrast image of nucleoids in living bacteria. The shape of the ribosome-free space does not reflect intracellular salt concentrations, nor do the Feulgen-positive areas. The previously observed dependency on the salt concentration of the growth medium seems to be due to permeabilization induced by the chemical fixative at room temperature. The ribosome-free space is more cleft in appearance than the nucleoid obtained by fixation with OsO4 but more confined than its very dispersed form found after aldehyde fixation.