Membrane vesiculation as a feature of the mammalian acrosome reaction.
Membrane vesiculation as a feature of the mammalian acrosome reaction.
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DOI:
10.1083/jcb.34.3.c1
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发表时间:
1967-09
影响因子:
7.8
通讯作者:
Austin, C R
中科院分区:
文献类型:
--
作者:
Barros, C;Bedford, J M;Franklin, L E;Austin, C R
The term membrane vesiculation is used in this report to denote the occurrence of multiple unions between two cellular membranes lying in close apposition, with the formation first of a double-walled fenestrated layer and ultimately of an array of separate membrane-bounded vesicles. The stages are illustrated in Fig. 1. The process depicted by these diagrams is essentially the same as that suggested by Tormey (9) to explain his observations on cells of the ciliary epithelium in which the formation of a fenestrated layer from two contiguous membranes was inferred to take place. In the ciliary epithelium, the membranes involved were the cell membranes lining invaginations and interdigitating processes of neighboring cells. Tormey cites other data and work of several other authors, which support the thesis that membrane vesiculation is often to be ascribed to fixation of tissue with osmium tetroxide, glutaraldehyde-fixed tissue usually showing instead intact parallel membranes. Cell membranes in close apposition in other situations have also been described as undergoing vesiculation. Thus, vesicles considered to have been derived from fused sperm and egg membranes were reported by the Colwins (5) in an electron microscope study of early fertilization in the annelid Hydroides hexagonus. Piko and Tyler (7) believed that the plasma and acrosome membranes in the rat spermatozoon are removed largely by vesiculation, as the spermatozoon passes into the egg. In the bull sperm head illustrated by Saacke and Almquist (8, Fig. 16), the row of vesicles arranged about the nucleus appears to have arisen by multiple fusions between plasma and acrosome membranes, and a closely similar change has been seen in a monkey spermatozoon (LE Franklin, unpublished data). In these observations on animal gametes, the assumption has been that the changes seen were attributable to a natural process; yet all these authors used osmium tetroxide as fixative, and consequently could have been misled by the production of artifacts. However, data have now been obtained with glutaraldehydefixed tissue which show that extensive vesiculation takes place between plasma and acrosome membranes in the course of the acrosome reaction evinced by hamster and rabbit spermatozoa as they pass through the egg investments. Information on the mammalian acrosome reaction has been meager at the ultrastructural level. By phase-contrast light microscopy, the occurrence of a change in and apparent detachment of the acrosome in living spermatozoa of several rodents (hamster, Libyan jird, guinea pig, Chinese hamster) were first described by Austin and Bishop (3)