Response to: "Rescuing the NIH before it is too late" from the Deputy Director for Extramural Research.

For a number of reasons, the NIH and the biomedical research community are facing a period of fiscal constraint after pronounced growth. In these difficult times, it is important that we all speak from the facts and work together to do a better job of explaining the importance of the nation's investment in biomedical research.

Immunolocalization of the sea urchin sperm receptor in eggs and maturing ovaries.

The sperm receptor from Strongylocentrotus purpuratus eggs is a high molecular weight proteoglycan-like molecule that inhibits fertilization species-specifically in a competition bioassay. A preparation of highly active sperm receptor that contained one major N-terminal sequence was used to generate polyclonal antibody in rabbits. This antibody species-specifically inhibited fertilization at low concentrations without interfering with fertilization envelope elevation.

Tissue and cell specificity of immobilin biosynthesis.

The mechanisms for the initiation of sperm motility have been poorly understood until recently. Immobilin is a novel mucin glycoprotein of high molecular weight found in the cauda epididymis of the rat that, at concentrations equivalent to those found in native cauda epididymal fluid, reversibly inhibits sperm motility. In this study, immobilin was purified from rat cauda epididymal fluid to apparent homogeneity and used to generate polyclonal antibody in rabbits.