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221.
The biosynthesis of neutral lipids in Mycobacterium smegmatis was studied using cell free extracts. Maximum neutral lipid production was obtained when the reaction mixture (400 microliter) consisted of 0.25 M potassium phosphate buffer (pH 7.5), 0.125 mM oleoyl-CoA, 3.75 mM sn-glycerol-3-P, 10 mM MgCl2 and 1.85 mg bovine serum albumin. No magnesium dependency for the acylation of sn-glycerol-3-P was observed. A slight stabilizing effect seemed to occur due to this ion. The enzyme phosphatidate phosphohydrolase, on the other hand, was shown to be magnesium dependent. The activity of this enzyme also appeared to be stimulated by high concentration (0.75 to 1.25 mM) of ATP which enhanced lipid formation at all concentrations tested (0.25 to 3.75 mM). A heat-stable protective factor having a molecular weight less than 16 000 which caused a stimulatory effect on sn-glycerol 3-phosphate acyltransferase activity was found in the cell-free extracts. Preliminary experiments suggest that the factor might be polysaccharide in nature. 相似文献
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Hogan Brenna Shen Zaiyi Zhang Hengdi Misbah Chaouqi Barakat Abdul I. 《Biomechanics and modeling in mechanobiology》2019,18(4):1095-1109
Biomechanics and Modeling in Mechanobiology - The effect of red blood cells and the undulation of the endothelium on the shear stress in the microvasculature is studied numerically using the... 相似文献
224.
Alliance of Proteomics and Genomics to Unravel the Specificities of Sahara Bacterium Deinococcus deserti 总被引:1,自引:0,他引:1
Arjan de Groot Rmi Dulermo Philippe Ortet Laurence Blanchard Philippe Gurin Bernard Fernandez Benoit Vacherie Carole Dossat Edmond Jolivet Patricia Siguier Michael Chandler Mohamed Barakat Alain Dedieu Valrie Barbe Thierry Heulin Suzanne Sommer Wafa Achouak Jean Armengaud 《PLoS genetics》2009,5(3)
To better understand adaptation to harsh conditions encountered in hot arid deserts, we report the first complete genome sequence and proteome analysis of a bacterium, Deinococcus deserti VCD115, isolated from Sahara surface sand. Its genome consists of a 2.8-Mb chromosome and three large plasmids of 324 kb, 314 kb, and 396 kb. Accurate primary genome annotation of its 3,455 genes was guided by extensive proteome shotgun analysis. From the large corpus of MS/MS spectra recorded, 1,348 proteins were uncovered and semiquantified by spectral counting. Among the highly detected proteins are several orphans and Deinococcus-specific proteins of unknown function. The alliance of proteomics and genomics high-throughput techniques allowed identification of 15 unpredicted genes and, surprisingly, reversal of incorrectly predicted orientation of 11 genes. Reversal of orientation of two Deinococcus-specific radiation-induced genes, ddrC and ddrH, and identification in D. deserti of supplementary genes involved in manganese import extend our knowledge of the radiotolerance toolbox of Deinococcaceae. Additional genes involved in nutrient import and in DNA repair (i.e., two extra recA, three translesion DNA polymerases, a photolyase) were also identified and found to be expressed under standard growth conditions, and, for these DNA repair genes, after exposure of the cells to UV. The supplementary nutrient import and DNA repair genes are likely important for survival and adaptation of D. deserti to its nutrient-poor, dry, and UV-exposed extreme environment. 相似文献
225.
Nicolas Gallois Batrice Alpha-Bazin Nicolas Bremond Philippe Ortet Mohamed Barakat Laurie Piette Abbas Mohamad Ali David Lemaire Pierre Legrand Nicolas Theodorakopoulos Magali Floriani Laureline Fvrier Christophe Den Auwer Pascal Arnoux Catherine Berthomieu Jean Armengaud Virginie Chapon 《The ISME journal》2022,16(3):902
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Arafa el-SA Zhu Q Shah ZI Wani G Barakat BM Racoma I El-Mahdy MA Wani AA 《Mutation research》2011,706(1-2):28-35
The use of innocuous naturally occurring compounds to overcome drug resistance and cancer recalcitrance is now in the forefront of cancer research. Thymoquinone (TQ) is a bioactive constituent of the volatile oil derived from seeds of Nigella sativa Linn. TQ has shown promising anti-carcinogenic and anti-tumor activities through different mechanisms. However, the effect of TQ on cell signaling and survival pathways in resistant cancer cells has not been fully delineated. Here, we report that TQ greatly inhibits doxorubicin-resistant human breast cancer MCF-7/DOX cell proliferation. TQ treatment increased cellular levels of PTEN proteins, resulting in a substantial decrease of phosphorylated Akt, a known regulator of cell survival. The PTEN expression was accompanied with elevation of PTEN mRNA. TQ arrested MCF-7/DOX cells at G2/M phase and increased cellular levels of p53 and p21 proteins. Flow cytometric analysis and agarose gel electrophoresis revealed a significant increase in Sub-G1 cell population and appearance of DNA ladders following TQ treatment, indicating cellular apoptosis. TQ-induced apoptosis was associated with disrupted mitochondrial membrane potential and activation of caspases and PARP cleavage in MCF-7/DOX cells. Moreover, TQ treatment increased Bax/Bcl2 ratio via up-regulating Bax and down-regulating Bcl2 proteins. More importantly, PTEN silencing by target specific siRNA enabled the suppression of TQ-induced apoptosis resulting in increased cell survival. Our results reveal that up-regulation of the key upstream signaling factor, PTEN, in MCF-7/DOX cells inhibited Akt phosphorylation, which ultimately causes increase in their regulatory p53 levels affecting the induction of G2/M cell cycle arrest and apoptosis. Overall results provide mechanistic insights for understanding the molecular basis and utility of the anti-tumor activity of TQ. 相似文献
229.
Praziquantel is the cornerstone of schistosomiasis control. A number of reports from endemic areas suggest that resistance or tolerance to praziquantel might exist in Schistosoma mansoni. Several explanations were postulated. The present work was designed to test the hypothesis that a low praziquantel (pzq) cure rate in Egypt is due to survival and maturation of immature stages that escaped pzq, which is effective against mature S. mansoni worms only. The study sample included 1351 children attending El Rouse primary school located in El Rouse village, Nile Delta, Egypt. All children received 2 pzq doses (40 mg/kg) 4 weeks apart. Diagnosis of S. mansoni infection and cure assessment were based on examination of 2 Kato slides prepared from a single stool sample collected before and 4 weeks after the first and second treatments. The cure rate was 78·8% after the first treatment and increased significantly to 90·8% after the second treatment. Egg reduction rates were 71·2% and 77·2% after 1 and 2 treatments respectively. Pre-treatment intensity of infection has a great influence on cure and egg reduction rates. Our results confirmed that low praziquantel cure rate, in Egypt, might be attributed, even partially, to survival and maturation of the immature S. mansoni stages that escaped pzq that is effective against mature worms only. 相似文献
230.