Antimicrobial activity of bovine seminal plasma

Abstract

Bovine seminal plasma (BSP) had marked antimicrobial activity against a wide variety of Gram-positive and Gram-negative bacteria. Several mycoplasma species were also sensitive to bpvine genital secretions. The activity spectrum differs significantly from that of other antimicrobial factors found in normal tissues such as egg white lysozyme, polylysine, salmine sulphate, spermidine phosphate, and human seminal plasma. Inhibitory activity of BSP fractions was measured with a standard gel diffusion assay which used M. lysodiekticus as the test organism. Results were expressed in terms of egg white lysozyme units. Ultra filtration at pH 2.5 indicated that the inhibitory material in BSP had a minimum molecular weight of less than 50 000 daltons, but it readily reformed into larger aggregates. Exposure to 0.0225m sodium citrate increased the apparent activity measured by the diffusion asasy and may have caused partial disaggregation. Exposure of BSP to 60°c and 80°c for 1 h destroyed 14% and 60–65% of the activity respectively. Trypsin, subtilisin, and thermolysin incubated with BSP at 40°c for 30 min completely destroyed the inhibitory activity in the seminal plasma.