Smith P F, Langworth T A, Mayberry W R, Houghland A E
J Bacteriol. 1973 Nov;116(2):1019-28. doi: 10.1128/jb.116.2.1019-1028.1973.
Thermoplasma acidophilum grows optimally under aeration at 59 C and pH 2. Both intact cells and membranes disaggregate below pH 1 and above pH 5, producing no sedimentable particles. Increase in ionic strength at pH 5 or below results in cellular lysis and membrane disaggregation. Membranous components produced by lysis at alkaline pH reaggregate upon reduction of both pH and ionic strength. Osmotic environment plays little role in cellular stability. Membranes prepared by sonic lysis at pH 5 exhibit vesicular structures and are composed of multiple proteins. Although the amino acid composition of the membrane proteins is similar to other mycoplasmal membranes, the number of free amino and carboxyl groups is less than half of those in Acholeplasma. Reduction of the number of free carboxyl groups results in membrane stabilization over a wide range of pH. Increase in the number of free amino groups reverses the stability of membranes relative to pH. Acidophily in Thermoplasma can be related to a significant reduction in repulsing negative charges on the membrane proteins.
嗜热栖热菌在通气条件下于59℃和pH 2时生长最佳。完整细胞和细胞膜在pH低于1和高于5时都会解聚，不会产生可沉淀颗粒。在pH 5或更低时离子强度增加会导致细胞裂解和膜解聚。在碱性pH下裂解产生的膜成分在pH和离子强度降低时会重新聚集。渗透环境对细胞稳定性影响很小。在pH 5时通过超声裂解制备的膜呈现出囊泡结构，并且由多种蛋白质组成。尽管膜蛋白的氨基酸组成与其他支原体膜相似，但游离氨基和羧基的数量不到无胆甾原体的一半。游离羧基数量的减少会导致膜在很宽的pH范围内稳定。游离氨基数量的增加会使膜相对于pH的稳定性逆转。嗜热栖热菌的嗜酸特性可能与膜蛋白上排斥负电荷的显著减少有关。
