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Biomedical subjects

G L Long

Publications and source records attributed to G L Long.

83 records · Page 5Linked to original sources
PubMed1973

The uptake of 2-deoxy-D-glucose by Pseudomonas aeruginosa and its regulation.

The non-metabolizable glucose analogue 2-deoxy-d-glucose is taken up by Pseudomonas aeruginosa against a concentration gradient, in a predominantly unchanged form. d-Glucose competitively inhibits 2-deoxy-d-glucose uptake and also causes a rapid exit of intracellular 2-deoxy-d-glucose. Thus these two sugars share the same stereospecific carrier system, and glucose transport can be studied reliably with 2-deoxy-d-glucose. The transport system is inducible, and is strongly repressed by a number of organic acids such as acetate, citrate, succinate, fumarate and malate, even in the presence of adequate excess of the inducer (d-glucose). Repression by organic acids can be relieved by transferring cells to a glucose medium, but in the presence of chloramphenicol the cells fail to recover from repression, indicating that the formation of the transport system involves the synthesis of protein. The results demonstrate that the regulation of glucose metabolism effected by citric acid-cycle intermediates in P. aeruginosa is manifest at the level of the glucose-transport system.

Acetates↗
PubMed1968

D-lactate specific pyridine nucleotide lactate dehydrogenase in animals.

A survey of representative invertebrates has revealed the presence of pyridine nucleotide-linked (D)-lactate dehydrogenase in a number of groups. All species studied contained either D(D)-or (L)L-lactate dehydrogenase, but no species contained both enzymes. The (D)-lactate dehydrogenase from Limulus polyphemus has been purified and has a molecular weight of 65,000.

Animals↗
PubMedDate not supplied

Construction, expression and preliminary characterization of glycosylation mutants of human protein S.

Human protein S (HPS) is a vitamin K dependent plasma glycoprotein involved in the regulation of activated protein C and possibly fibrinolysis. Its c-DNA sequence shows three N-glycosylation consensus sequences (Asn-X-Ser/Thr). In order to study influence of N-linked glycosylation on HPS function, set of mutants of HPS was constructed. Mutants were generated, starting from an SV40/Adeno derived pD5HPS2 expression vector, using PCR enabled, site specific methodology. They included single amino acid substitutions at each of three N-glycosylation consensus sequences: Asn458-->Gln, Ser460-->Gly, Asn468-->Gln, Thr470-->Gly, Asn489-->Gln, Thr491-->Gly. Variant HPS were expressed in stable 293 human kidney cell lines in the presence of vitamin K1 (we did not succeed in expressing variant Asn489-->Gln) and purified from conditioned media using pseudoaffinity chromatography on QAE-Sepharose. Variant Asn468-->Gln showed decreased gamma-carboxyglutamate content. All of the mutants were active in a clotting type assay based on factor Va inactivation, and they were compared to wt-HPS and plasma HPS. In conclusion, we have constructed, expressed and purified set of HPS mutants useful in studying the role of N-glycosylation in HPS function.

Base Sequence↗