Localization of prostaglandin on the plasmalemma of rabbit sperm.

Prostaglandin and prostaglandin receptors were localized on unwashed ejaculate rabbit sperm utilizing ferritin conjugated antibody to prostaglandin. Reaction was obtained over the acrosomal portion of the plasma membrane, with a greater aggregation over the apex of the head. The remainder of the head plasmalemma and flagellum showed no deposits of of reaction product. The reaction did not occur if the sperm were washed prior to incubation with the labelled antisera. However enhanced binding of ferritin was demonstrated if washed sperm were pre-incubated in PGE1. No reaction was seen in similar studies with human sperm.     

Possible role of β-endoglucanase in the degradation of the cell wall polysaccharides in more and less resistant to pre-harvest sprouting triticale varieties

The β-endoglucanase is one of the enzymes taking part in the degradation of the cell wall structural polysaccharides. The use of two Triticale varieties differing in their resistance to the preharvest sprouting allowed the comparison of that enzyme activity and changes in the internal structure of the cell wall observed in the light and electron microscope. The most interesting observations seem to be the channels and even the holes in the walls of aleurone cells found mostly in the samples showing the elevated activities of β-endoglucanase. As those samples concern the grains of a lower resistance to pre-harvest sprouting, it might be suggested that the loosening of the wall structure may be one of the probable mechanisms in facilitating the enzyme, metabolite and water translocations through the grain tissues. Those changes can accelerate the water imput into the grain, the metabolic process and thus the increased susceptibility to sprouting.