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Biomedical subjects

S R Grimes

Publications and source records attributed to S R Grimes.

43 records · Page 3Linked to original sources
PubMed1975

Changes in nuclear proteins of rat testis cells separated by velocity sedimentation.

The technique of velocity sedimentation at unit gravity has been used to separate rat testis cell suspensions into fractions enriched in particular cell types. Changes in the nuclear proteins from the various fractions have been characterized by polyacrylamide gel electrophoresis, and correlated with the changing morphology of the nucleus during spermatogenesis. The most striking alterations in both protein composition and nuclear morphology occur during spermatid maturation as both histone and non-histone proteins are replaced by highly basic, low molecular weight, spermatidal proteins. This replacement process is accompanied by a quantitative reduction in both histone and non-histone proteins. The synthesis of at least three basic proteins has been identified with late stage spermatids. One of these proteins is a highly basic sperm-specific protein containing high levels of cyst(e)ine and arginine. A second protein synthesized in late stage spermatids is lysine rich, while the third protein contains cyst(e)ine and co-migrates with histone F2a1 on acid-urea polyacrylamide gels. The changes in protein composition of rat testis nuclei after irradiation or hypophysectomy reflect the resulting changes in the cellular composition of the testis. After selective elimination of the germinal cells by irradiation, the electrophoretic pattern of acid-soluble proteins from the testis is very similar to that of somatic tissue. Thus, the cellular specificity of nuclear proteins demonstrated here using cell separation techniques is also apparent following treatments which selectively alter the cellular composition of the testis.

Amino Acids↗
PubMedDate not supplied

Characterization of proteoglycans produced by rat pleural mesothelial cells in vitro.

The mesothelial cell envelopes the surface of the parietal and visceral pleura. These cells are known to synthesize most of the protein constituents of the pleural basement membrane and interstitium. This study examined the ability of a rat pleural mesothelial cell line to synthesize proteoglycans in vitro. Cells were labeled with inorganic 35SO4 to label the glycosaminoglycan moiety of proteoglycans. The medium and combined cell membrane/extracellular matrix fractions contained 73 and 25% of the proteoglycan radioactivity, respectively. The medium contained a single chondroitin/dermatan sulfate proteoglycan of approximately 190 kDa, consistent with biglycan. As determined by Northern analysis of steady-state levels of messenger RNA, the cells contained message for biglycan. Stimulation of the cells with epidermal growth factor resulted in the appearance of a second chondroitin/dermatan sulfate proteoglycan of approximately 97 kDa, characteristic of decorin. The cell membrane/matrix contained a biglycan-like chondroitin/dermatan proteoglycan and several heparan sulfate proteoglycans. Pleural mesothelial cells in vitro are capable of synthesizing a variety of interstitial and basement membrane proteoglycans.

Animals↗