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J E Perry

Publications and source records attributed to J E Perry.

36 records · Page 2Linked to original sources
PubMed1975

The release of high-molecular-weight alkaline phosphatase and leucine aminopeptidase into the media of cultured human cells.

Using exclusion from Sepharose 4B as our criterion, we have found a high-molecular-weight form of alkaline phosphatase and of leucine aminopeptidase which are released into the culture media by the FL amnion cell line. A low-molecular-weight form of leucine aminopeptidase is also found to contribute to the total levels of this enzyme in the media. The levels of these enzymes increased during the growth cycle of the culture, paralleling the increase in cell density, suggesting that the two events may be related. This phenomen in culture suggests a possible explanation for the appearance of similar enzyme forms in patient serum and fluids originating from diseased tissue.

Alkaline Phosphatase↗
PubMed1974

Effect of helium gas at elevated pressure on iron transport and growth of Escherichia coli.

Helium at an ambient pressure of 68 at m with 0.2 atm of O(2) shortened by 1 to 1.5 h the lag phase for growth of Escherichia coli in minimal medium supplemented with 2 muliters of cell-free culture filtrate (CFF) per ml or with 1 muM 2,3-dihydroxybenzoylserine (DHBS), an iron chelator. The lag phase of cultures not exposed to helium could be shortened by use of supplements, but higher concentrations were required-10 to 30 muliters of CFF per ml or 10 to 50 muM DHBS. Strain AN 193 of E. coli, which requires the DHBS precursor 2,3-dihydroxybenzoic acid (DHBA), grew well in media with 10 muM DHBA when exposed to helium at 68 atm, whereas 100 muM DHBA was required for growth in unexposed cultures. In the presence of 100 muM DHBA plus 1.0 muM ethylenediaminetetraactic acid, growth was inhibited at 1 and 68 atm. Growth was restored, however, by the addition of 0.1 muM FeSO(4) at 68 atm and 1.0 muM FeSO(4) at 1 atm, but lag times were invariably shorter in the pressurized cultures. Hydrostatic pressures of 68 atm did not reduce the lag phase in the presence of CFF, DHBS, or DHBA. Our results suggest that 68 atm of helium pressure, but not hydrostatic pressure, elicited a more rapid transport of iron into the cells.

Benzoates↗