Incorporation of Label from Acetate and Laurate into the Mannan of Leishmania donovani via the Glyoxylate Cycle |
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Authors: | FRANK P. KEEGAN J. JOSEPH BLUM |
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Affiliation: | Department of Biology, Guilford College, Greensboro, North Carolina 27410;Division of Physiology, Department of Cell Biology and Cellular Biophysics, Duke University Medical Center, Durham, North Carolina 27710 |
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Abstract: | Leishmania donovani promastigotes in late-stationary phase incorporated label from [2-14C]acetate and [1-14C]laurate into the mannose residues of mannan, thus confirming the presence of a functional glyoxylate bypass in these parasitic protozoa. Isolated, washed calls also incorporated label from [2-14C]acetate and [1-14C]laurate into mannan during a 1-hr incubation in buffer. Glucose had no effect on label incorporation into mannan, but glutamate caused over a four-fold increase in incorporation from [2-14C]acetate and a 2.4-fold increase from [1-14C]laurate. Staurosporine, a protein kinase inhibitor that inhibits glutamate and alanine oxidation, did not inhibit label incorporation from [2-14C]acetate into mannan. Hyperosmolality caused about a 33% inhibition of label incorporation into mannan. These results show the glyoxylate cycle and/or the subsequent biosynthetic pathway from fructose-6-phosphate to mannan are subject to regulation. |
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Keywords: | Hyperosmolality. |
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