ULTRASTRUCTURAL ASPECTS OF CELL ELONGATION CELLULOSE SYNTHESIS AND SPORE DIFFERENTIATION IN ACYTOSTELIUM LEPTOSOMUM A CELLULAR SLIME MOLD
ULTRASTRUCTURAL ASPECTS OF CELL ELONGATION CELLULOSE SYNTHESIS AND SPORE DIFFERENTIATION IN ACYTOSTELIUM LEPTOSOMUM A CELLULAR SLIME MOLD
复制标题
DOI：
10.2307/2440967
复制
发表时间：
1968-01-01
影响因子：
3
通讯作者：
HEMMES, DE
中科院分区：
文献类型：
--
作者：
HOHL, HR;HAMAMOTO, ST;HEMMES, DE
细体隐孢子虫（Acytosteelasticleptosomum）的营养性粘液变形菌是一种细胞型黏菌，具有典型的真核细胞外观。已确定存在网质体。在聚集和顶点过程中的细胞的伸长似乎是由纵向穿过细胞的密集的微纤维束介导的。存在微管;然而，它们是随机取向的，与细胞伸长或茎内纤维素微纤丝的方向没有相关性。各种囊泡、多泡体和溶酶体样液泡似乎参与了柄物质的产生和运输。然而，囊泡很少将其内容物直接排空到细胞外。似乎茎的纤维状物质在质膜附近或直接在质膜上聚集，然后可以看到它们流走，成为茎的一个组成部分。一个不寻常的结构，H-体，是形成了大量的顶点期间，表明其可能参与茎合成。在孢子形成之前，H体与细胞质的其他部分一起至少部分地通过涉及自噬空泡的过程从细胞中除去。这些空泡也存在于孢子中，似乎是相当复杂和广泛的空泡装置的一部分，包括食物空泡，收缩空泡，溶酶体样结构，可能还有H体。孢子被由一个厚的外壁和一个纤维状的亚结构组成，质膜内侧有两条薄而致密的带。用高锰酸钡染色切片材料，可以突出孢子外壁和柄的纤维状性质。
Vegetative myxamoebae of Acytostelium leptosomum, a cellular slime mold, have the appearance of typical eucaryotic cells. The presence of dictyosomes has been established. Elongation of the cells during aggregation and culmination appears to be mediated by dense bundles of microfibrils traversing the cells longitudinally. Microtubules are present; however, they are randomly oriented and no correlation can be made with cell elongation or with the direction of the cellulose microfibrils within the stalk. A variety of vesicles, multivesicular bodies, and lyso-some-like vacuoles seems to be involved in producing and transporting stalk material to the vicinity of the stalk. However, only rarely do the vesicles empty their contents directly to the outside of the cells. It seems rather that the fibrillar material of the stalk is assembled near or directly at the plasmalemma, and can then be seen to stream away and become an integral part of the stalk. An unusual structure, the H-body, is formed in great abundance during culmination indicating its possible involvement in stalk synthesis. The H-bodies are removed from the cells prior to spore formation together with other portions of the cytoplasm at least partly by a process involving auto-phagic vacuoles. These vacuoles, which are also present in the spores, appear to be part of a rather complex and extensive vacuolar apparatus including the food vacuoles, contractile vacuoles, lysosome-like structures, and possibly the H-bodies. The spore coat consists of a heavy outer wall with a fibrillar substructure and 2 thin, dense bands lining the inside of the plasmalemma. The fibrillar nature of both the outer spore wall and the stalk was accentuated by using barium permanganate to stain sectioned material.