Phosphoprotein Phosphatase Activity of Sea Urchin Spermatozoa

Osmotic adaptation of sea-urchin spermatozoa.

Spermatozoa depend on their motility to accomplish their function of fertili¬ zation. In the case of sea-urchins and other marine organisms, the ionic com¬ position of sea-water is among the environmental factors that affect motility and longevity (Bishop, 1962). We have started studies of specific ion concen¬ tration changes in the sea-water as they affect the motility of sea-urchin spermatozo...

The Physiology of Sea-urchin Spermatozoa

Since Gray showed in 1928 that dilute suspensions of sea-urchin spermatozoa respire at a higher rate, per spermatozoon, than dense suspensions, evidence has been accumulating which suggests that sea-urchin spermatozoa are in different physiological conditions in suspensions of different densities. This paper is concerned with these differences and, in particular, with the effects of rigorous pH...

The Physiology of Sea - Urchin Spermatozoa Catalase

Phosphoprotein inhibition of calcium-stimulated exocytosis in sea urchin eggs

We have investigated the role of protein phosphorylation in the control of exocytosis in sea urchin eggs by treating eggs with a thio-analogue of ATP. ATP gamma S (adenosine 5'-O-3-thiotriphosphate) is a compound which can be used as a phosphoryl donor by protein kinases, leading to irreversible protein thiophosphorylation (Gratecos, D., and E.H. Fischer. 1974. Biochem. Biophys. Res. Commun. 58...

The Physiology of Sea-urchin Spermatozoa Action of Versene

A description of the physiology of sea-urchin spermatozoa requires, among other things, an explanation of two special characteristics which these spermatozoa possess. First, immediately after dilution, the Og uptake per spermatozoon is higher in a dilute than in a dense suspension. Secondly, the decline in sperm motility and fertilizing capacity is more rapid in a dilute than in a dense suspens...