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221.
Arpi Majumder Chirantan Roy Choudhury Guillaume Pilet Nathalie Daro Nitin Chattopadhyay 《Inorganica chimica acta》2005,358(13):3855-3864
Two new coordination polymers {[Mn(H2btc)(phen)(H2O)2]H2btc · H2O}n (1) [H3btc = 1,3,5-benzene tricarboxylic acid, phen = phenanthroline] and {[Zn3(btc)2(H2O)8](H2O)4}n (2) have been synthesised and structurally characterised. Both the complexes crystallise as 1D chain, which further propagates through ligand-based hydrogen bonding interactions into a 3D supramolecular architecture. Supramolecular framework of 1 is constructed by [Mn(H2btc)(phen)(H2O)2]+ as well as the constituent materials-uncoordinated H2btc− and water molecules. Complex 2 exists as a corrugated chain with both the bridging and terminal Zn2+ ions and each zinc centre is coordinated to four water molecules. Both 1 and 2 are stacked by mutual π-stacking of the ligands and exhibit strong fluorescence emission band at 414 and 400 nm, respectively. 相似文献
222.
Choudhury A Mukherjee P Basu SK George A Rath S Bal V 《Journal of immunology (Baltimore, Md. : 1950)》2000,164(4):1713-1721
Scavenger receptor (SR)-specific delivery by maleylation of a ubiquitous self-protein, Ig, to SR-bearing APCs results in self-limiting induction of autoimmune effects in vivo. Immunization with maleyl-Ig breaks T cell tolerance to self-Ig and causes hypergammaglobulinemia, with increases in spleen weight and cellularity. The majority of splenic B cells show an activated phenotype upon maleyl-Ig immunization, leading to large-scale conversion to a CD138+ phenotype and to significant increases in CD138-expressing splenic plasma cells. The polyclonal B cell activation, hypergammaglobulinemia, and autoreactive Ig-specific T cell responses decline over a 2-mo period postimmunization. Following adoptive transfer, T cells from maleyl-Ig-immune mice taken at 2 wk postimmunization can induce hypergammaglobulinemia in the recipients, but those taken at 10 wk postimmunization cannot. Hypergammaglobulinemia in the adoptive transfer recipients is also transient and is followed by an inability to respond to fresh maleyl-Ig immunization, suggesting that the autoreactive Ig-specific T cells are inactivated peripherally following disruption of tolerance. Thus, although autoreactive T cell responses to a ubiquitous self-Ag, Ig, are induced by SR-mediated delivery to professional APCs in vivo resulting in autoimmune pathophysiological effects, they are effectively and rapidly turned off by inactivation of these activated Ig-specific T cells in vivo. 相似文献
223.
Choudhury A Singh RK Moniaux N El-Metwally TH Aubert JP Batra SK 《The Journal of biological chemistry》2000,275(43):33929-33936
224.
The constitution of mollugogenol-F, a new triterpenoid sapogenin isolated from Mollugo hirta (family: Ficoidaceae), has been established as 3β,16β,22-trihydroxyisohopane. 相似文献
225.
Sphingolipids (SLs) are concentrated at the plasma membrane where they play important roles in cell-cell communication, host-pathogen interactions, and cell signaling events. Our laboratory has used fluorescent SL analogs and SL-binding toxins to elucidate mechanisms by which SLs are internalized by endocytosis and subsequently sorted and transported to various intracellular compartments. These studies have relied on the use of temperature shift protocols, co-localization studies with compartment-specific markers, selective biochemical treatments that inhibit specific endocytic mechanisms, and the expression of dominant negative proteins (e.g., rabs) that block specific steps in transport. These methods are presented here so that they can be utilized by others for the study of endocytic trafficking of lipids and other molecules. 相似文献
226.
Reconstitution of O-specific lipopolysaccharide expression in Burkholderia cenocepacia strain J2315, which is associated with transmissible infections in patients with cystic fibrosis 下载免费PDF全文
Ortega X Hunt TA Loutet S Vinion-Dubiel AD Datta A Choudhury B Goldberg JB Carlson R Valvano MA 《Journal of bacteriology》2005,187(4):1324-1333
227.
228.
During enrichments to search for soil bacteria that form the volatile ketones, acetone and butanone, we isolated pure cultures
of Pseudomonas aureofaciens, P. fluorescens, and P. putida that excrete the β-keto-acid, 3-oxopentanoate (3-OPA), when grown on heptanoic acid as carbon source. Analysis of 3-OPA used
enzymatic decarboxylation by acetoacetate decarboxylase to yield butanone, which was detected by headspace gas chromatography.
The formation of 3-OPA was strongly dependent on heptanoic acid concentration, the level of oxygen, and the state of growth,
and was not seen with even-chain or other odd-chain fatty acids. Uptake of 3-OPA during stationary phase of growth is probably
related to polyhydroxyalkanoate (PHA) formation in these isolates. A model for formation and release of 3-OPA is proposed.
Received: 28 August 2000 / Accepted: 2 October 2000 相似文献
229.
Experimental infection of Trypanosoma (Trypanozoon) evansi in Bandicota bengalensis produces an acute disease course leading to untimely death of the bandicoot rat. The sequential alteration of liver, spleen, lung, kidney, and heart was studied on the 5th, 8th, 12th, and 14th days postinoculation. The rats showed inflammatory, degenerative, and necrotic changes in these organs. In liver, pseudolobule formation, necrosis and hemorrhage within the sinusoids, and fatty degeneration of hepatic cells were the predominant histopathological changes. The changes were destructive and irreversible. In spleen giant cells aggregation and granulomatous lesion, i.e., accumulation of histiocytes, were the protective changes, whereas tissue and cell damage indicated irreversible degeneration. The gradual development of intrabronchus inflammation, aggregation of inflammatory cells around the alveoli, congestion of bronchioles, septal edema, atrophy of alveolar walls, migration of macrophages, and emphysema were the histopathological changes noticed in the lungs of the infected rats. The affected kidney showed infiltration of lymphocytes, hemorrhage in the interlobular space, and glomerulitis as the irreversible and destructive changes in the rats. There was degeneration of myocardium in the hearts of the rats. The histopathological changes in these organs are compared with those studied in surra, human sleeping sickness disease, and African trypanosomiasis. Possible mechanisms for these histological changes in the visceral organs are discussed. 相似文献
230.