ACQUISITION OF VIABLE-LIKE SURFACE-PROPERTIES OF SPERM CELLS BY ADSORPTION OF SEMINAL PLASMA-PROTEINS REVEALED BY CENTRIFUGAL COUNTERCURRENT DISTRIBUTION

By using centrifugal countercurrent distribution in dextran/polyethyle ne glycol two-phase system, we show that the acquisition of adsorbed s eminal plasma proteins by the sperm cell surface modifies the partitio n behaviour of bull spermatozoa reproducing that of alive cells. Thus, addition of increasing concentrations of proteins from the seminal pl asma promoted a saturable enhanced affinity of the cells to the polyet hylene glycol-rich phase in which alive cells preferentially partition . On the contrary, treatment with Tween provoked the opposite effect.