Author
|
Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 4/24/2006 Publication Date: 7/1/2006 Citation: Purdy, P.H. 2006. Ubiquitination of boar sperm: what does this reveal about sperm physiology? Annual Meeting of the Society for the Study of Reproduction, Omaha, NE, July 29-August 1, 2006. p.189. Interpretive Summary: Limited data on sperm ubiquitination have shown negative correlations (bovine and human) and positive correlations (human) with sperm quality, but its effects on boar sperm are largely unknown. This research determined that ubiquitination positively influenced the physiology of frozen-thawed sperm from 12 boars. Negative correlations between the presence of ubiquitin and DNA damaged sperm were detected indicating that increasing proportions of ubiquitinated sperm correlates with lower levels of DNA damage. In addition, the presence of ubiquitin on sperm positively correlated with increased frozen-thawed motility, frozen-thawed progressive motility, and frozen-thawed plasma membrane integrity. Contrary to findings with other species, the results illustrate that the presence of ubiquitin on boar sperm is not indicative of poor quality but rather sperm with a lower incidence of DNA damage, greater motility and a higher proportion of cells with intact plasma membranes. Technical Abstract: Limited data on sperm ubiquitination have shown negative correlations (bovine and human) and positive correlations (human) with sperm quality, but its effects on boar sperm are largely unknown. This research determined the influence of ubiquitination on motility, mitochondrial activity, membrane fluidity and membrane integrities in fresh and frozen-thawed sperm from 12 boars. Sperm motility and progressive motility were determined using computer automated semen analysis (greater than or equal to 500 sperm per sample). Mitochondrial activity, plasma membrane and live acrosomal integrity, membrane fluidity, ubiquitination and chromatin stability (TUNEL) of at least 10,000 cells per fresh and frozen-thawed boar sperm sample were determined using flow cytometry. The post-thaw ubiquitin-positive proportion of sperm from single-staining (ubiquitin only) and from dual-staining (ubiquitin and TUNEL) flow cytometry analyses were used as the independent variables in linear regression analyses. Dependent variables in linear regression included motility, progressive motility, mitochondrial activity, live acrosomal integrity, plasma membrane integrity, and membrane fluidity. A significant predictive model (P < 0.05) was derived using single-staining for defective chromatin (r² = -.43). Significant regression models were derived for frozen-thawed motility (r² = .52), frozen-thawed progressive motility (r² = .4) and frozen-thawed plasma membrane integrity (r² = .41) when dual-staining was used as the independent variable. In addition, a significant negative correlation (P < 0.05) between single-stained ubiquitinated sperm and frozen-thawed chromatin damage (r = -.65) was observed. Dual-stained ubiquitinated sperm correlated positively (P < 0.05) with frozen-thawed motility (r = .72), frozen-thawed progressive motility (r = .63), and frozen-thawed plasma membrane integrity (r = .64). Contrary to findings with other species, the results illustrate that ubiquitination is not indicative of poor quality but indicate sperm with a lower incidence of chromatin damage, greater motility, and a higher proportion of cells with intact plasma membranes. |
