INTRAMITOCHONDRIAL FIBERS WITH DNA CHARACTERISTICS
INTRAMITOCHONDRIAL FIBERS WITH DNA CHARACTERISTICS
复制标题
具有 DNA 特征的线粒体内纤维
作者：
M. M. Nass;S. Nass
电镜下观察鸡胚线粒体，可见低电子不透明的无嵴区。用四氧化二锇、高锰酸钙、高锰酸钾、甲醛、丙烯醛、丙烯醛接四氧化二锇、醋酸铀酰接高锰酸钙和醋酸-酒精固定后，可以观察到这些区域。用氢氧化铅或醋酸铀酰染色，或两者同时染色，会导致这些区域内纤维材料的密度增加。纤维结构的外观随固定剂的使用而变化；四氧化二锇固定后，材料呈块状条状（直径达400a），而在脱水前用醋酸铀酰处理四氧化二锇固定组织后，纤维结构可以看到为15至30 A的原纤维。用乙二胺四乙酸酯（EDTA）代替醋酸铀酰使线粒体原纤维变粗。用高锰酸钙或高锰酸钾固定后，或先用醋酸铀酰再用高锰酸钙双重固定后，纤维的图案和超微结构与四氧化锇-醋酸铀酰固定后的纤维相似，只是其中一些纤维直径略大（可达50 a）。其他固定剂不能很好地保存纤维。经甲醛固定后，纤维呈强烈的团块状，用丙烯醛或醋酸醇固定后，纤维难以识别。用过氧化氢处理四氧化锇固定的切片，改善了醋酸铀酰和氢氧化铅对含核酸结构的染色，并且线粒体纤维在电子束中的密度也增加了。染色特征表明鸡胚线粒体纤维物质为含核酸结构，其不同固定后的变化外观与先前报道或本文描述的细菌和蓝藻核质相似。这些结果，加上在随附的通讯中描述的结果，表明这些线粒体含有DNA。
Chick embryo mitochondria, studied with the electron microscope, show crista-free areas of low electron opacity. These areas are observable after fixation with osmium tetroxide, calcium permanganate, potassium permanganate, formaldehyde, acrolein, acrolein followed by osmium tetroxide, uranyl acetate followed by calcium permanganate, and acetic acid-alcohol. Staining of sections with lead hydroxide or uranyl acetate, or with both, resulted in an increased density of a fibrous material within these areas. The appearance of the fibrous structures varied with the fixative employed; after fixation with osmium tetroxide the material was clumped and bar-like (up to 400 A in diameter), whereas after treatment of osmium tetroxide-fixed tissues with uranyl acetate before dehydration the fibrous structures could be visualized as 15 to 30 A fibrils. Treatment with ethylenediaminetetraacetate (EDTA) in place of uranyl acetate coarsened the mitochondrial fibrils. After fixation with calcium permanganate or potassium permanganate, or a double fixation by uranyl acetate followed by calcium permanganate, the fibers appeared to have a pattern and ultrastructure similar to that observed after the osmium tetroxide-uranyl acetate technique, except that some of them had a slightly greater diameter (up to 50 A). Other fixatives did not preserve the fibers so well. The fibers appeared strongly clumped by formaldehyde fixation, and were difficult to identify after fixation with acrolein or acetic acid-alcohol. The staining of nucleic acid-containing structures by uranyl acetate and lead hydroxide was improved by treatment of osmium tetroxide-fixed sections with hydrogen peroxide, and the mitochondrial fibers also had an increased density in the electron beam after this procedure. The staining characteristics suggest the fibrous material of chick embryo mitochondria to be a nucleic acid-containing structure, and its variable appearance after different fixations parallels that previously reported, or described in this paper, for the nucleoplasm of bacteria and blue-green algae. The results, in addition to those described in the accompanying communication, indicate that these mitochondria contain DNA.