ISSN:
0886-1544
Keywords:
Caenorhabditis elegans spermatozoa
;
cell motility
;
electron microscopy
;
cell-substrate contact
;
2-nm filaments
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The locomotion of C. elegans spermatozoa resembles, in many respects, the crawling movements of other eukaryotic cells. However, these sperm contain surprising little actin, which plays no apparent role in this cell's motility. Electron microscopy has revealed that crawling spermatozoa retain a strict morphological polarity so that the organelle-filled cell body is separated from the pseudopod by an array of cytoplasmic laminar membranes. When sperm crawl only the pseudopod contacts the substrate; the cell body is either pulled behind or carried on top of the rear portion of the pseudopod. Fingerlike projections which extend forward from the leading edge of the pseudopod initiate contact with the substrate. The underside of the pseudopod exhibits areas of close (40 nm separation) membrane-substrate association with intervening areas of wide (up to 300 nm) membrane-substrate gaps. The pseudopod cytoplasm contains 2-nm filaments but no filamentous actin has been observed. These 2-nm filaments were detected in thin sections of crawling cells and in negative-stained remnants of spermatozoa disrupted by either hypotonic buffer on Triton X-100. The filaments are found both free in the cytoplasm and closely associated with the cytoplasmic face of the plasma membrane and are usually oriented along the long axis of the cell. Neither the identity nor the function of these filaments has been established although their location and orientation suggest that they may be involved in generating propulsion.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cm.970030405
