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Biomedical subjects

J D Harding

Publications and source records attributed to J D Harding.

At least 37 records · Page 2Linked to original sources
PubMed1975

Changes in intestinal cell kinetics in the small intestine of lactating mice.

The enlargement of the small intestine of mice during lactation is due, at least in part, to hyperplasia in the mucosal crypts and villi. The number of cells per crypt increases by 130% and the cell production rate by 63% after 15 days of lactation. These parameters were measured from crypt squashes and sections using both double-label and PLM techniques. Neither the numbers of crypts and villi in the small intestine nor the turnover time of post-mitotic cells on the villi changed. A number of factors appear to act in concert during lactation to trigger this increase in epithelial cell number in the small intestine. The experiments reported suggest a role for the increased quantity of food consumed by the lactating animal, for changing hormonal levels, and for the increased demands placed on the body by milk production.

Animals↗
PubMed1974

RNA polymerase assembly in vitro. Temperature dependence of reactivation of denatured core enzyme.

The Escherichia coli RNA polymerase core molecule, after denaturation in 6 M guanidine hydrochloride, can be completely reactivated in the absence of sigma subunit. Reactivation is temperature dependent. At 4 degrees a renatured-inactive preparation is formed that has most of the secondary structure of the original native molecule but has a reduced sedimentation coefficient and a smaller Stokes radius and is, therefore, of lower molecular weight. Upon warming to 37 degrees the renatured-inactive preparation is converted in a time-dependent process to the renatured-active preparation, which has the same amount of secondary structure and same molecular weight as native RNA polymerase. Since the renatured-inactive material is probably composed of subunit assemblies and can be readily reactivated, it should be useful for studying the subunit interactions and control of assembly of RNA polymerase.

Binding Sites↗