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J Oppenheim

Publications and source records attributed to J Oppenheim.

25 records · Page 2Linked to original sources
PubMed1973

Labile inhibitor of lymphocyte transformation in plasma from a patient and subacute sclerosing panencephalitis.

A thermolabile inhibitory factor of mitogen-induced lymphocyte transformation was observed in the fresh plasma of one patient in stage 3 of subacute sclerosing panencephalitis (SSPE) and not in three other patients in various stages of the disease. Thus, its relevance to SSPE is not clear. The plasma factor was removed by adsorption onto human and animal cells and polystyrene beads, and it was found in the 7S globulin fraction of the effluent from gel permeation chromatography.

DNA↗
PubMed1970

Correlation of ultrastructure in Azotobacter vinelandii with nitrogen source for growth.

Azotobacter synthesizes an extensive internal membranous nework when grown with air (N(2)), i.e., under conditions when these bacteria fix nitrogen. Very slight quantities of internal membrane, concentrated mainly about the cell periphery, are formed when Azotobacter grows with fixed nitrogen, i.e., ammonia and amino acids. Compared to cells growing with ammonia, cells utilizing atmospheric nitrogen as the sole nitrogen source are smaller in size and volume, grow one-third slower, and lack detectable poly-beta-hydroxybutyrate.

Air↗
PubMed1970

Properties of a soluble nitrogenase in Azotobacter.

A nitrogenase system that remains in the supernatant fluid after centrifuging for 3 hr at 180,000 x g can be extracted from Azotobacter vinelandii by osmotic lysis of the bacteria. This nitrogenase preparation is oxygen-labile and appears to be similar, though not identical, to that obtained from Clostridium pasteurianum. The particulate characteristic and oxygen stability of previously described preparations are likely due to the method of cell disruption, e.g., in the French pressure cell. The data support a nitrogenase model system in the intact cell in which oxygen-labile enzymes are protected from oxygen by the extensive internal membranous system which Azotobacter synthesize only when they fix nitrogen.

Acetylene↗