title: Actin localisation and the effect of cytochalasin D on the osmotic tolerance of cauda epididymidal kangaroo spermatozoa.
abstract: 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 (0-200 microM). 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.
authors.affiliation: School of Animal Studies, University of Queensland, Gatton, Australia.
authors.forename: R
authors.initials: R
authors.lastname: McClean
authors.forename: C
authors.initials: C
authors.lastname: MacCallum
authors.forename: D
authors.initials: D
authors.lastname: Blyde
authors.forename: W
authors.initials: W
authors.lastname: Holt
authors.forename: S
authors.initials: S
authors.lastname: Johnston
mesh_terms: D000177:Acrosome / Q000187:drug effects / Q000378:metabolism; D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D015925:Cryopreservation / Q000379:methods; D015638:Cytochalasin D / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004822:Epididymis / Q000166:cytology*; D007614:Macropodidae; D008297:Male; D009995:Osmosis / Q000187:drug effects / Q000502:physiology; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology; D013082:Sperm Tail / Q000187:drug effects / Q000378:metabolism; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000199:Actins; D015638:Cytochalasin D