Pellon J R, Ulmer K M, Gomez R F
Appl Environ Microbiol. 1980 Aug;40(2):358-64. doi: 10.1128/aem.40.2.358-364.1980.
The folded chromosome or nucleoid of Escherichia coli was analyzed by low-speed sedimentation in neutral sucrose gradients after in vivo heat treatment. Heat treatment of cultures at 50 degree C for 15, 30, and 60 min resulted in in vivo association of the nucleoids with cellular protein. Structural changes, determined by the increase in speed dependence of the nucleoids from heated cells, also occurred. These changes were most likely due to the unfolding of the typical compact nucleoid structure. The nucleoids from heated cells also had notably higher sedimentation coefficients (3,000 to 4,500S) than nucleoids from control cells (1,800S). These nucleoids did not contain greater than normal amounts of membrane phospholipids or ribonucleic acid. We propose that the protein associated with the nucleoids from heated cells causes the observed sedimentation coefficient increases.
对经体内热处理后的大肠杆菌折叠染色体或类核进行了中性蔗糖梯度低速沉降分析。将培养物在50℃下热处理15、30和60分钟,导致类核在体内与细胞蛋白结合。由加热细胞的类核对速度依赖性增加所确定的结构变化也发生了。这些变化很可能是由于典型紧密类核结构的展开。加热细胞的类核沉降系数(3000至4500S)也明显高于对照细胞的类核(1800S)。这些类核所含的膜磷脂或核糖核酸量并不高于正常水平。我们认为,与加热细胞的类核相关的蛋白质导致了观察到的沉降系数增加。