
TY  - JOUR
A1  - Holt, W. V. 
A1  - Penfold, L. M. 
A1  - Johnston, S. D. 
A1  - Temple-Smith, P. 
A1  - Shaw, J. 
A1  - McCallum, C. 
A1  - Lindemans, W. 
A1  - Blyde, D. 
T1  - Cryopreservation of macropodid spermatozoa: new insights from the cryomicroscope
JF  - Reproduction, Fertility and Development
JO  - Reprod. Fertil. Dev.
Y1  - 2000
VL  - 11
IS  - 6
SP  - 345
EP  - 353
KW  - genetic resource banks, kangaroo, plasma membrane, semen, wallaby.
UR  - https://doi.org/10.1071/RD99076 
N2  - This study examined the effects of cooling and cryopreservation upon macropod spermatozoa (eastern grey kangaroo, Macropus giganteus and red-necked wallaby, Macropus rufogriseus). Sperm survival during and after freezing to &#8211;30&#x02DA;C or &#8211;70&#x02DA;C in minimum essential medium (MEM) + 5, 10, 20 or 30% (v/v) glycerol, MEM + 10 or 20% (v/v) ethylene glycol and MEM containing a mixture of 7.5% (v/v) glycerol + 10% (v/v) dimethylsulphoxide was examined by cryomicroscopy. The MEM/glycerol mixtures permitted better post-thaw sperm recovery than the other cryoprotectants. After freezing to &#8211;30&#x02DA;C at 10&#x02DA;C min &#8211;1 in 20% glycerol, then rewarming at 20&#x02DA;C min &#8211;1 , flagellar activity resumed in more than 50% of spermatozoa when the temperature increased into the range 5&#8211;10&#x02DA;C. However, as the temperature increased, into the range 20&#8211;25&#x02DA;C, motility declined rapidly so that less than 5% motile cells were seen at 35&#x02DA;C. Spermatozoa in MEM without cryoprotectant were also examined by cryomicroscopy to evaluate changes in flagellar configuration, swimming behaviour and viability during cooling from 35&#x02DA;C to approximately &#8211;7&#x02DA;C, and rewarming to 35&#x02DA;C. Cooling from 35 to 28&#x02DA;C induced kangaroo spermatozoa to exhibit rigid principal-piece bending and non-linear motility, which was reversed by further cooling and the spermatozoa resumed their normal linear movement. Rewarming induced principal-piece bending in the range of 20&#8211;30&#x02DA;C, but this effect was reversed by further warming. Although red-necked wallaby spermatozoa showed these effects, they also exhibited a tendency to form rosette-like clusters during rewarming, especially when the temperature reached approximately 14&#x02DA;C. The clusters were induced when the flagellar end-pieces became anteriorly reflected, producing hook-like flagellar conformations, which then became interlinked. 
ER  -

