title: Determination of activable proacrosin/acrosin in bovine sperm using an irreversible isocoumarin serine protease inhibitor.
abstract: The activable proacrosin/acrosin levels in bovine sperm were examined using fluorescent staining and flow cytometry. The proportion of sperm with active acrosin were determined using the biotinylated isocoumarin serine protease inhibitor, Bi-Aca-Aca-OMe-IC (BIC). The presence of bound inhibitor on sperm was then determined by secondary labeling with avidin fluorescein conjugate. The proportion of sperm with activable proacrosin/acrosin was assessed by using detergent treatment to expose the active acrosin in intact sperm. The difference between untreated and detergent-treated aliquots was used to estimate the proportion of sperm with activable proacrosin/acrosin. In the 24-h stored samples from six bulls, the mean proportion of sperm with activable proacrosin/acrosin was 78.8 +/- 2.8%, whereas the mean proportion with exposed acrosin after cryopreservation of these samples was 55.8 +/- 4.1%. Significant differences (p < 0.05) were found among bulls in the proportion of sperm with activable proacrosin/acrosin both before and after cryopreservation. Activable proacrosin/acrosin levels in samples of cryopreserved sperm from five bulls were not correlated with fertility. These results do indicate, however, that the irreversible isocoumarin serine protease inhibitor BIC can be used to determine the proportion of sperm cells that retain activable proacrosin/acrosin after cryopreservation and thawing.
authors.affiliation: Department of Agricultural Economics, University of Nevada, Reno 89557, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Palencia
authors.forename: D L
authors.initials: DL
authors.lastname: Garner
authors.forename: D
authors.initials: D
authors.lastname: Hudig
authors.forename: D W
authors.initials: DW
authors.lastname: Holcombe
authors.forename: C A
authors.initials: CA
authors.lastname: Burner
authors.forename: D
authors.initials: D
authors.lastname: Redelman
authors.forename: G C
authors.initials: GC
authors.lastname: Fernandez
authors.forename: A S
authors.initials: AS
authors.lastname: Abuelyaman
authors.forename: C M
authors.initials: CM
authors.lastname: Kam
authors.forename: J C
authors.initials: JC
authors.lastname: Powers
mesh_terms: D000176:Acrosin / Q000032:analysis*; D000818:Animals; D002417:Cattle; D004792:Enzyme Precursors / Q000032:analysis*; D005434:Flow Cytometry; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D008297:Male; D008856:Microscopy, Fluorescence; D012661:Semen / Q000737:chemistry / Q000166:cytology; D015842:Serine Proteinase Inhibitors; D013094:Spermatozoa / Q000737:chemistry*
chemical_list: D004792:Enzyme Precursors; D007202:Indicators and Reagents; D015842:Serine Proteinase Inhibitors; C022438:proacrosin; D000176:Acrosin