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21.
Karmakar S Banik NL Patel SJ Ray SK 《Apoptosis : an international journal on programmed cell death》2007,12(11):2077-2087
Glioblastoma is the most prevalent and highly malignant brain tumor that continues to defy current treatment strategies. This
investigation used all-trans retinoic acid (ATRA) and taxol (TXL) as a combination therapy for controlling the growth of human glioblastoma T98G xenografted
in athymic nude mice. Histopathological examination revealed that ATRA induced differentiation and combination of ATRA and
TXL caused more apoptosis than either treatment alone. Combination therapy decreased expression of telomerase, nuclear factor
kappa B (NFκВ), and inhibitor-of-apoptosis proteins (IAPs) indicating suppression of survival factors while upregulated Smac/Diablo.
Combination therapy also changed expression of Bax and Bcl-2 proteins leading to increased Bax:Bcl-2 ratio, mitochondrial
release of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9. Increased activities of calpain and caspase-3 degraded
270 kD α-spectrin at the specific sites to generate 145 kD spectrin breakdown product (SBDP) and 120 kD SBDP, respectively.
Further, increased activity of caspase-3 cleaved inhibitor-of-caspase-activated DNase (ICAD). In situ double immunofluorescent
labelings showed overexpression of calpain, caspase-12, caspase-3, and AIF during apoptosis, suggesting involvement of both
caspase-dependent and caspase-independent pathways for apoptosis. Our investigation revealed that treatment of glioblastoma
T98G xenografts with the combination of ATRA and TXL induced differentiation and multiple molecular mechanisms for apoptosis. 相似文献
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Mamtesh Singh Prasun Kumar Subhasree Ray Vipin C. Kalia 《Indian journal of microbiology》2015,55(3):235-249
Polyhydroxyalkanoates (PHAs) as an alternative to synthetic plastics have been gaining increasing attention. Being natural in their origin, PHAs are completely biodegradable and eco-friendly. However, consistent efforts to exploit this biopolymer over the last few decades have not been able to pull PHAs out of their nascent stage, inspite of being the favorite of the commercial world. The major limitations are: (1) the high production cost, which is due to the high cost of the feed and (2) poor thermal and mechanical properties of polyhydroxybutyrate (PHB), the most commonly produced PHAs. PHAs have the physicochemical properties which are quite comparable to petroleum based plastics, but PHB being homopolymers are quite brittle, less elastic and have thermal properties which are not suitable for processing them into sturdy products. These properties, including melting point (Tm), glass transition temperature (Tg), elastic modulus, tensile strength, elongation etc. can be improved by varying the monomeric composition and molecular weight. These enhanced characteristics can be achieved by modifications in the types of substrates, feeding strategies, culture conditions and/or genetic manipulations. 相似文献
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Margarethe Draga Elizabeth B. Madgett Cassandra J. Vandenberg David du Plessis Aisling Kaufmann Petra Werler Prasun Chakraborty Noel F. Lowndes Kevin Hiom 《Molecular and cellular biology》2015,35(22):3829-3840
The Fanconi anemia DNA repair pathway is pivotal for the efficient repair of DNA interstrand cross-links. Here, we show that FA-defective (Fancc−) DT40 cells arrest in G2 phase following cross-link damage and trigger apoptosis. Strikingly, cell death was reduced in Fancc− cells by additional deletion of the BRCA1 tumor suppressor, resulting in elevated clonogenic survival. Increased resistance to cross-link damage was not due to loss of toxic BRCA1-mediated homologous recombination but rather through the loss of a G2 checkpoint. This proapoptotic role also required the BRCA1-A complex member ABRAXAS (FAM175A). Finally, we show that BRCA1 promotes G2 arrest and cell death by prolonging phosphorylation of Chk1 on serine 345 after DNA damage to sustain arrest. Our data imply that DNA-induced cross-link death in cells defective in the FA pathway is dependent on the ability of BRCA1 to prolong cell cycle arrest in G2 phase. 相似文献
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In order to preserve genetic information in stress conditions, bacterial DNA is organized into higher order nucleoid structure. In this paper, with the help of Atomic Force Microscopy, we show the different structural changes in mycobacterial nucleoid at different points of growth in the presence of different concentrations of glucose in the medium. We also observe that in Mycobacterium smegmatis, two different Dps proteins (Dps1 and Dps2) promote two types of nucleoid organizations. At the late stationary phase, under low glucose availability, Dps1 binds to DNA to form a very stable toroid structure. On the other hand, under the same condition, Dps2-DNA complex forms an incompletely condensed toroid and finally forms a further stable coral reef structure in the presence of RNA. This coral reef structure is stable in high concentration of bivalent ion like Mg(2+). 相似文献
28.
Advanced glycation end products (AGEs) are known to be involved in the pathogenesis of several diseases, in particular diabetes, via signaling through their receptor. Numerous studies have been carried out on protein-sugar interactions at very high concentrations of the latter. The objective of this investigation was to determine the effects of nonenzymatic glycation induced by reducing sugars on the secondary structure of human serum albumin (HSA) under different physiological conditions and to correlate that with expression of RAGE (receptor for advanced glycation end products) on HUVECs (human umbilical vein endothelial cells) in a controlled hemodynamic environment. Our results indicate that RAGE expression is shear stress modulated and that glycated HSA enhances the expression further. The secondary structure of AGE-HSA derived from glucose at 20 mM contains higher α-helical content and elicits maximum expression of the receptor. The effect of shear stress at 10 dynes cm(-2) is independent of AGE-HSA. 相似文献
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Karmakar S Muhuri DC Dasgupta SC Nagchaudhuri AK Gomes A 《Indian journal of experimental biology》2004,42(5):452-460
A haemorrhagic protein toxin (SA-HT) was isolated and purified from the spine extract of the Indian venomous butterfish, S. argus Linn, by two step ion exchange chromatography. The toxin was homogeneous in native and SDS-PAGE gel. SDS-molecular weight of the toxin was found to be 18.1 +/- 0.09 kDa. SA-HT produced severe haemorrhage on stomach wall but devoid of cutaneous haemorrhage. UV, EDTA, trypsin, protease, cyproheptadine, indomethacin, acetylsalicylic acid and BW755C treatment significantly antagonized the haemorrhagic activity of SA-HT. The toxin produced dose and time dependent oedema on mice hind paw, which was significantly encountered by cyproheptadine, indomethacin and BW755C. SA-HT increased capillary permeability on guinea pig dorsal flank. On isolated guineapig ileum, rat fundus and uterus, SA-HT produced slow contraction which was completely antagonised by prostaglandin blocker SC19220. On isolated rat duodenum, SA-HT produced slow relaxation. SA-HT significantly increased plasma plasmin, serum MDA level and decreased serum SOD level indicating the possible involvement of cyclooxygenase and lipooxygenase pathway. 相似文献