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1.
We have studied the activities of 2′,3′-cyclic nucleotide 3′-phosphohydrolase, 1,2-diacylglycerol: CDPethanolamine phosphoethanolamine
transferase (EC 2.7.8.1), and 1,2-diacylglycerol: CDPcholine phosphocholine transferase (EC 2.7.8.2) in developing rat brain
gray matter and white matter. The specific activity of cyclic nucleotide phosphohydrolase was 5–8 fold higher in white matter
than in gray matter at all ages. No significant changes were observed during development. The specific activity of phosphocholine
transferase was 2 to 3 fold higher than phosphoethanolamine transferase at all ages both in gray and white matter. Both phosphocholine
transferase and phosphoethanolamine transferase increased more than 2 fold in specific activity between 14 and 90 days of
age. The total activity of phosphocholine transferase also showed an increase during development. The apparentK
m values for nucleotides and dicaprin were similar in gray matter and white matter. Except for lowK
m values for nucleotides at 14 days of age, no significant changes were observed during development. Changes in rates of glycerophospholipid
synthesis may be partly due to the specific activities of these enzymes but are also determined by the quantities of substrates
and inhibitors and by affinities for the substrates.
Special Issue dedicated to Dr. Eugene Kreps. 相似文献
2.
Long-chain acyl coenzyme A (CoA) synthetase in homogenates and microsomes from rat brain gray and white matter was studied. The formation of the thioesters of CoA was studied upon addition of [1-14C]-labeled fatty acids. The maximal activities were seen with linoleic acid, followed by arachidonic, palmitic, and docosahexaenoic acids in both gray and white matter homogenates and microsomes. The specific activities in microsomes were 3–5 times higher than in homogenates. The presence of Triton X-100 in the assay system enhanced the activity of long-chain acyl CoA synthetase in homogenates. The effect was more pronounced in palmitic and docosahexaenoic acid activation. The apparentK
m values andV
max values for palmitic and docosahexaenoic acids were much lower than for linoleic and arachidonic acids. The presence of Triton X-100 in the medium caused a definite decrease in the apparentK
m and Vmax values for all the fatty acid except palmitic acid in which case the reverse was true. There were no significant differences observed in the kinetic measurements between gray and white matter microsomes. These findings are similar to those resulting from the known interference of Triton X-100 in the measurement of kinetic variables of long-chain acyl CoA synthetase of liver microsomes. In this work, no correlation was observed between the fatty acid composition of gray and white matter and the capacity of these tissues for the activation of different fatty acids. 相似文献
3.
Studies were made of the effects of maternal thiamine deficiency on rat whole brain, gray matter and white matter lipids. Mothers were fed a high protein diet (controls) or thiamine deficient high protein diet (thiamine deficient, TD) from 14th day of gestation through lactation. An additional group (pair fed control, PFC) was pair fed with the thiamine deficient group. The TD pups started showing symptoms of abnormalities in posture, arched back and hind limb paralysis from 16th day of lactation. Significant deficits were found in body weight and brain weight of TD and PFC pups. But the deficits seem to be more in the former group. Significant deficits were observed with regard to the concentration of lipids such as galactolipids, phospholipids and plasmalogens in the whole brain of TD and PFC pups at 21 days of age. Additional deficits were also found in the concentration of cholesterol in PFC pups. Gray matter lipids from TD pups seem to be completely spared. However, deficits were found in galactolipid and ganglioside concentrations in PFC pups. The deficits found in the concentration of different lipids in white matter are similar to those observed in whole brain. These results suggest that the effects of thiamine deficiency may be partly due to resultant growth retardation and partly due to the deficiency of thiamine per se. 相似文献
4.
Arunkumar Venkatesan Jie Geng Malathi Kandarpa Sanjeeva Joseph Wijeyesakere Ashwini Bhide Moshe Talpaz Irina D. Pogozheva Malini Raghavan 《The Journal of cell biology》2021,220(7)
Myeloproliferative neoplasms (MPNs) are frequently driven by mutations within the C-terminal domain (C-domain) of calreticulin (CRT). CRTDel52 and CRTIns5 are recurrent mutations. Oncogenic transformation requires both mutated CRT and the thrombopoietin receptor (Mpl), but the molecular mechanism of CRT-mediated constitutive activation of Mpl is unknown. We show that the acquired C-domain of CRTDel52 mediates both Mpl binding and disulfide-linked CRTDel52 dimerization. Cysteine mutations within the novel C-domain (C400A and C404A) and the conserved N-terminal domain (N-domain; C163A) of CRTDel52 are required to reduce disulfide-mediated dimers and multimers of CRTDel52. Based on these data and published structures of CRT oligomers, we identify an N-domain dimerization interface relevant to both WT CRT and CRTDel52. Elimination of disulfide bonds and ionic interactions at both N-domain and C-domain dimerization interfaces is required to abrogate the ability of CRTDel52 to mediate cell proliferation via Mpl. Thus, MPNs exploit a natural dimerization interface of CRT combined with C-domain gain of function to achieve cell transformation. 相似文献
5.
Regulation of ProMMP-1 and ProMMP-3 activation by tissue factor pathway inhibitor-2/matrix-associated serine protease inhibitor 总被引:5,自引:0,他引:5
Rao CN Mohanam S Puppala A Rao JS 《Biochemical and biophysical research communications》1999,255(1):94-98
Tissue factor pathway inhibitor-2 (TFPI-2)/matrix-associated serine protease inhibitor (MSPI), a 32- to 33-kDa Kunitz-type serine protease inhibitor, inhibits plasmin and trypsin. Because plasmin and trypsin are involved in the activation of promatrix metalloproteases proMMP-1 and proMMP-3, we investigated the role of TFPI-2/MSPI in the activation of these proenzymes. Both plasmin and trypsin activated proMMP-1 by converting the 53-kDa proenzyme to the partially active 43-kDa polypeptide; this activity was inhibited by TFPI-2/MSPI. Similarly, TFPI-2/MSPI inhibited the conversion of 66-kDa proMMP-3 to the activated 45- and 30-kDa polypeptides by plasmin and trypsin. Because plasmin is involved in the physiological activation of proMMP-3, we tested whether TFPI-2/MSPI inhibits the activation of proMMP-3 by HT-1080 fibrosarcoma cells and urokinase-charged HeLa cells. We found that the inhibitor inhibited proMMP-3 activation by HT-1080 cells and urokinase-charged HeLa cells. Collectively, our results suggest that TFPI-2/MSPI indirectly regulates MMP-1- and MMP-3-catalyzed matrix proteolysis by regulating the activation of proMMP-1 and proMMP-3. 相似文献
6.
7.
Shalindra Ranasinghe Renu Wickremasinghe Sanjeeva Hulangamuwa Ganga Sirimanna Nandimithra Opathella Rhaiza DC Maingon Vishvanath Chandrasekharan 《Memórias do Instituto Oswaldo Cruz》2015,110(8):1017-1023
Leishmania donovani is the known causative agent of both cutaneous
(CL) and visceral leishmaniasis in Sri Lanka. CL is considered to be under-reported
partly due to relatively poor sensitivity and specificity of microscopic diagnosis.
We compared robustness of three previously described polymerase chain reaction (PCR)
based methods to detectLeishmania DNA in 38 punch biopsy samples
from patients presented with suspected lesions in 2010. Both,
Leishmaniagenus-specific JW11/JW12 KDNA and LITSR/L5.8S internal
transcribed spacer (ITS)1 PCR assays detected 92% (35/38) of the samples whereas a
KDNA assay specific forL. donovani (LdF/LdR) detected only 71%
(27/38) of samples. All positive samples showed a L. donovani
banding pattern upon HaeIII ITS1 PCR-restriction fragment length polymorphism
analysis. PCR assay specificity was evaluated in samples containing
Mycobacterium tuberculosis, Mycobacterium
leprae, and human DNA, and there was no cross-amplification in JW11/JW12
and LITSR/L5.8S PCR assays. The LdF/LdR PCR assay did not amplify M.
leprae or human DNA although 500 bp and 700 bp bands were observed in
M. tuberculosis samples. In conclusion, it was successfully shown
in this study that it is possible to diagnose Sri Lankan CL with high accuracy, to
genus and species identification, using Leishmania DNA PCR
assays. 相似文献
8.
Verma S Nagarathnam D Shao J Zhang L Zhao J Wang Y Li T Mull E Enyedy I Wang C Zhu Q Altieri M Jordan J Dang TT Reddy S 《Bioorganic & medicinal chemistry letters》2005,15(8):1973-1977
A series of aminobenzimidazole-substituted pyrimidines were synthesized and evaluated for biochemical activity against CDK1. A high-speed parallel synthesis approach enabled the identification of a potent lead series having improved potency in the CDK1 assay (IC(50)<10nM). Cell cycle analysis showed that the compounds induced a G2/M block. Docking studies were carried out with a CDK1 homology model, and provide a rationale for the observed activities. 相似文献
9.
Sanjeeva Balasuriya 《Journal of theoretical biology》2010,266(4):657-666
The speed and the minimum carrying capacity needed for a successful population expansion into new territory are addressed using a reaction-diffusion model. The model is able to encapsulate a rich collection of ecological behaviours, including the Allee effect, resource depletion due to consumption, dispersal adaptation due to population pressure, biological control agents, and a range of breeding suppression mechanisms such as embryonic diapause, delayed development and sperm storage. It is shown how many of these phenomena can be characterised as density-dependence in a few fundamental ecological parameters. With the help of a powerful mathematical technique recently developed by Balasuriya and Gottwald (J. Math. Biol. 61, pp. 377-399, 2010), explicit formulae for the effect on the speed and minimum carrying capacity are obtained. 相似文献
10.