scholarly journals Dynamic nuclear polarization of biocompatible13C-enriched carbonates for in vivo pH imaging

2016 ◽  
Vol 52 (14) ◽  
pp. 3030-3033 ◽  
Author(s):  
D. E. Korenchan ◽  
R. R. Flavell ◽  
C. Baligand ◽  
R. Sriram ◽  
K. Neumann ◽  
...  
Keyword(s):  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Ph Imaging ◽  
Low Toxicity ◽  
High Concentrations ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

High concentrations of hyperpolarized13C-bicarbonate are generatedviarapid hydrolysis of highly polarizable, low-toxicity carbonate precursors.

scholarly journals Effects of anti-microtubular agents and cycloheximide on the metabolism of chylomicron cholesteryl esters by hepatocyte suspensions

1977 ◽  
Vol 162 (2) ◽  
pp. 367-377 ◽  
Author(s):  
A Nilsson
Keyword(s):  
Cholesteryl Ester ◽  
Cholesteryl Esters ◽  
Chylomicron Remnant ◽  
Trypsin Treatment ◽  
Heparin Plasma ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

1. Post-heparin plasma that promoted rapid hydrolysis of about 90% of the triacylglycerol markedly stimulated the uptake or binding of chylomicron cholesteryl ester by suspended hepatocytes. The net hydrolysis of chyle cholesteryl ester after the uptake by the cells was, however, slower than in vivo. 2. The cholesteryl ester uptake in the presence of post-heparin plasma was larger if the cells had been preincubated for 2h. It was inhibited by the presence of colchicine, vinblastine or cycloheximide during the preincubation, and by mild trypsin treatment of the preincubated cells. 3. The results suggested that the anti-microtubular agents, but not cycloheximide, also inhibited the hydrolysis of chyle cholesteryl ester after uptake or binding to the cells. 4. The uptake of isolated chylomicron remnant particles was more efficient than that of native chyle lipoproteins. It was, however, still stimulated by heparin alone and by post-heparin plasma. The heparin-stimulated uptake was markedly decreased if cycloheximide was present during the preincubation period.

scholarly journals Dynamic nuclear polarization facilitates monitoring of pyruvate metabolism in Trypanosoma brucei

2017 ◽  
Vol 292 (44) ◽  
pp. 18161-18168 ◽  
Author(s):  
You Zhuo ◽  
Ciro D. Cordeiro ◽  
S. Khan Hekmatyar ◽  
Roberto Docampo ◽  
James H. Prestegard
Keyword(s):  
Trypanosoma Brucei ◽  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Hep G2 ◽  
Hek 293 ◽  
Mammalian Cell Lines ◽  
Microbial Systems ◽  
Viable Method ◽  
Pathogenic Protozoan

Dynamic nuclear polarization provides sensitivity improvements that make NMR a viable method for following metabolic conversions in real time. There are now many in vivo applications to animal systems and even to diagnosis of human disease. However, application to microbial systems is rare. Here we demonstrate its application to the pathogenic protozoan, Trypanosoma brucei, using hyperpolarized 13C1 pyruvate as a substrate and compare the parasite metabolism with that of commonly cultured mammalian cell lines, HEK-293 and Hep-G2. Metabolic differences between insect and bloodstream forms of T. brucei were also investigated. Significant differences are noted with respect to lactate, alanine, and CO2 production. Conversion of pyruvate to CO2 in the T. brucei bloodstream form provides new support for the presence of an active pyruvate dehydrogenase in this stage.

scholarly journals Lipid metabolism in Trypanosoma brucei: utilization of myristate and myristoyllysophosphatidylcholine for myristoylation of glycosyl phosphatidylinositols

1996 ◽  
Vol 318 (2) ◽  
pp. 575-581 ◽  
Author(s):  
Karl A WERBOVETZ ◽  
Paul T ENGLUND
Keyword(s):  
Fatty Acid ◽  
Trypanosoma Brucei ◽  
Surface Glycoprotein ◽  
Free System ◽  
Glycosyl Phosphatidylinositol ◽  
Physiological Importance ◽  
Fatty Acid Species ◽  
Rapid Hydrolysis ◽  
Hydrolysis Of

Myristate is the exclusive fatty acid species in the glycosyl phosphatidylinositol (GPI) anchor of the Trypanosoma brucei variant surface glycoprotein (VSG). [3H]Myristate can be incorporated into T. brucei GPIs by two distinct processes known as fatty acid remodelling and myristate exchange. Myristoyllysophosphatidylcholine (M-LPC) can also serve as a myristate donor for VSG in trypanosomes [Bowes, Samad, Jiang, Weaver and Mellors (1993) J. Biol. Chem. 268, 13885–13892]. We have studied in detail the myristoylation of GPIs using a [3H]M-LPC substrate. Labelling of VSG and free GPIs by [3H]M-LPC in cultured trypanosomes occurred at the same rate as with [3H]myristate. Concurrent with GPI labelling, there was rapid hydrolysis of [3H]M-LPC to generate extracellular [3H]myristate. Experiments in a trypanosomal cell-free system indicated that GPI labelling by fatty acid remodelling and myristate exchange was also equally efficient with [3H]M-LPC and [3H]myristate. Furthermore, both ATP and CoA are required for the myristoylation of GPIs by [3H]M-LPC. These experiments suggest that GPI myristoylation from M-LPC involves hydrolysis of M-LPC to free myristate. To address the physiological importance of myristate and M-LPC in VSG myristoylation, we radiolabelled trypanosomes in vivo with both substrates in medium containing serum, and found that [3H]myristate labelled VSG and GPIs more efficiently. Thus, VSG myristoylation by free myristate may be favoured in bloodstream trypanosome infections.

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