The Absorption by Boar Spermatozoa of Zinc Bound to Low Molecular Weight Ligands

Abstract

Most of the zinc accumulated by boar spermatozoa at 4\ s=deg\ C from seminal plasma appears to arise from the low molecular weight zinc ligands. Zinc added to semen in low concentrations (0\m=.\1 to 0\m=.\6 mm) is preferentially absorbed by the spermatozoa, particularly at 4\s=deg\C.

Effect of seminal plasma zinc–binding proteins on motility and membrane integrity of canine spermatozoa stored at 5°C

“…Proteins are the main constituent of prostatic secretion which is the source of high quantities of zinc ions (17). It is known that zinc ions fulfil their functions in the reproductive system due to binding different (low and high) molecular weight ligands (5,26). The findings of our previous study demonstrated the presence of high molecular weight zinc-binding protein ligands in boar and canine seminal plasma (18,19).…”

“…Under cold shock conditions spermatozoa absorb eight times more zinc than at physiological temperature (5). Moreover, excessively high zinc content in spermatozoa exerts inhibitory effect on their motility (13).…”

“…Since bioavailable zinc binds to low and high molecular weight proteins, the seminal plasma zinc binding protein-ligands seem to be significantly important in the effect of zinc on sperm functions (4). The data on seminal plasma zinc binding protein-ligands is sparse and concern only humans (24,26) and boars (5,14,19,29), while there is a complete lack of information regarding dogs. Our findings have demonstrated for the first time the characteristics of zinc-binding proteins (ZnBPs) secreted by the canine prostate, which might be used in the reproductive processes (18).…”

Scanning-Electron-microscopy—X-ray microanalysis and distribution of elements within the head of human spermatozoa

“…As already studied on spermatozoa of other mammals, the presence of various elements in the human spermatozoon has been achieved by spectrophotometry [2,3,16,18,19,241 or by microanalysis on ultrathin sections of fixed material observed with an electron microscope [ 1, 14, 201. Scanning-electron-microscopy (SEM) combined with energy dispersion x-ray analysis has been utilized, allowing indirect evaluation of the surface charge of spermatozoa by detection of the iron bound to the sperm surface, after staining with colloidal iron hydroxide [ 131.…”

The constant ratio of the zinc content of boar spermatozoa at 4 C and room temperature

“…This ratio was obtained under a wide range of conditions and in spite of considerable differences in the room temperature zinc content of the spermatozoa separated from native seminal plasma. In previous work (Boursnell & Noble, 1975) the regression lines of sperm zinc content with zinc added to whole semen revealed this ratio between the 4°C and room temperature slopes ; and, more surprisingly, washed spermatozoa resuspended in buffered zinc citrate also demonstrated it.…”