This study examined the hypothesis that filamentous actin associated with the complex cytoskeleton of the kangaroo sperm head and tail may be contributing to lack of plasma membrane plasticity and a consequent loss of membrane integrity during cryopreservation. In the first study, the distribution of G and F actin within Eastern Grey Kangaroo (EGK, Macropus giganteus) cauda epididymidal spermatozoa was successfully detected using DNAse-FITC and a monoclonal F-actin antibody (ab205, Abcam), respectively. G-actin staining was most intense in the acrosome but was also observed with less intensity over the nucleus and mid-piece. F-actin was located in the sperm nucleus but was not discernable in the acrosome or sperm tail. To investigate whether cytochalasin D (a known F-actin depolymerising agent) was capable of improving the osmotic tolerance of EGK cauda epididymal spermatozoa, sperm were incubated in hypo-osmotic media (61 and 104 mOsm) containing a range of cytochalasin D concentrations (0-200M). Cytochalasin D had no beneficial effect on plasma membrane integrity of sperm incubated in hypo-osmotic media. However, when EGK cauda epididymidal sperm were incubated in isosmotic media, there was a progressive loss of sperm motility with increasing cytochalasin D concentration. The results of this study indicated that the F-actin distribution in cauda epididymidal spermatozoa of the EGK was surprisingly different from that of the Tammar Wallaby (M. eugenii) and that cytochalasin-D does not appear to improve the tolerance of EGK cauda epididymidal sperm to osmotically induced injury.
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Keywords:
CRYOPRESERVATION;
CYTOCHALASIN D;
F-ACTIN;
KANGAROO;
OSMOTIC TOLERANCE;
SPERMATOZOA
Document Type: Research Article
Publication date:
01 June 2006
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CryoLetters is a bimonthly international journal for low temperature sciences, including cryobiology, cryopreservation or vitrification of cells and tissues, chemical and physical aspects of freezing and drying, and studies involving ecology of cold environments, and cold adaptation
The journal publishes original research reports, authoritative reviews, technical developments and commissioned book reviews of studies of the effects produced by low temperatures on a wide variety of scientific and technical processes, or those involving low temperature techniques in the investigation of physical, chemical, biological and ecological problems.