Silva M T, Sousa J C, Polónia J J, Macedo M A, Parente A M
Biochim Biophys Acta. 1976 Aug 4;443(1):92-105. doi: 10.1016/0005-2736(76)90493-4.
The ultrastructural study of membrane organization in gram-positive bacteria related to the OSO4 fixation conditions revealed that large, complex mesosomes are observed only when the bacteria are subjected to an initial fixation with 0.1%OSO4 in the culture broth, as in the prefixation step of the Ryter-Kellenberger procedure. Evidence was obtained suggesting that the large mesosomes are produced by this prefization. The kinetic study of the membrane morphological alterations occurring during the prefixation of Bacillus cereus with 0.1%OSO4 in the culture broth showed that the amount of mesosome material increases linearly from zero to a maximum observed at 1.7 min of prefixation and that at about this time a maximum is reached for the number of mesosomes per unity of cell area and for the average individual mesosome area. The large mesosomes observed in gram-positives fixed by the complete Ryter-Kellenberger procedure would be the result of the membrane-damaging action of 0.1%OSO4. Such damaging action was deduced from the observation thay 0.1%OSO4 quickly lyses protoplasts and induces a quick and extensive leakage of intracellular K+ from B. cereus and Streptococcus faecalis. In support of that interpretation is the observation that in bacteria subjected to several membrane-damaging treatments, mesosome-like structures are seen after three different fixation procedures. In bacteria initially fixed with 1% OSO4, 4% OSO4 or 2.5% glutaraldehyde, no large complex mesosomes are observed, small and simple invaginations of the cytoplasmic membrane being present. The size of these minute mesosomes is inversely proportional that causes of fixation. Uranyl acetate was found among the studied fixatives the one to the rate the least damage to bacterial membranes. This fixative satisfactorily preserves protoplasts. In bacteria initially fixed with uranyl acetate no mesosomes were found. The results of the present work throw serious doubts on the existence of mesosomes, both large and small, as real structures of bacterial cells. It is proposed that a continuous cytoplasmic membrane without infoldings (mesosomes) would be the real pattern of membrane organization in gram-positives.
关于革兰氏阳性菌膜组织的超微结构研究与四氧化锇（OSO4）固定条件相关，结果显示，只有当细菌在培养液中用0.1% OSO4进行初始固定时，如在Ryter - Kellenberger方法的预固定步骤中那样，才会观察到大型、复杂的间体。有证据表明，这种预固定会产生大型间体。对蜡样芽孢杆菌在培养液中用0.1% OSO4进行预固定过程中发生的膜形态改变的动力学研究表明，间体物质的量从零开始线性增加，在预固定1.7分钟时达到最大值，并且大约在这个时候，每单位细胞面积的间体数量和平均单个间体面积也达到最大值。在通过完整的Ryter - Kellenberger方法固定的革兰氏阳性菌中观察到的大型间体，将是0.1% OSO4对膜的损伤作用的结果。这种损伤作用是从以下观察结果推断出来的：0.1% OSO4能迅速裂解原生质体，并诱导蜡样芽孢杆菌和粪链球菌细胞内钾离子快速大量泄漏。支持该解释的是以下观察结果：在经过几种膜损伤处理的细菌中，在三种不同的固定程序后都能看到类间体结构。在最初用1% OSO4、4% OSO4或2.5%戊二醛固定的细菌中，未观察到大型复杂间体，仅存在细胞质膜的小而简单的内陷。这些微小间体的大小与固定剂的种类成反比。在所研究的固定剂中，发现醋酸铀对细菌膜的损伤最小。这种固定剂能令人满意地保存原生质体。在最初用醋酸铀固定的细菌中未发现间体。本研究结果对大小间体作为细菌细胞真实结构的存在提出了严重质疑。有人提出，没有内褶（间体）的连续细胞质膜将是革兰氏阳性菌膜组织的真实模式。
