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81.
Prajna Gayen Sudipta Maitra Sutapa Datta Santi P. Sinha Babu 《Journal of biosciences》2010,35(1):73-77
Wolbachia are symbiotic endobacteria that infect the majority of filarial nematodes, including Wuchereria bancrofti, Brugia malayi and Onchocerca volvulus. Recent studies have suggested that Wolbachia are necessary for the reproduction and survival of filarial nematodes and have highlighted the use of antibiotic therapy
such as tetracycline/doxycycline as a novel method of treatment for infections caused by these organisms. Before such therapy
is conceived and implemented on a large scale, it is necessary to assess the prevalence of the endosymbiont in W. bancrofti from different geographical locations. We present data from molecular and electron microscopic studies to provide evidence
for Wolbachia symbiosis in W. bancrofti microfilariae collected from two districts (Bankura and Birbhum) of West Bengal, India. 相似文献
82.
Nibedita Mahata Debasis PoreAmit Pal Manoj K. Chakrabarti 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
IP3-mediated calcium mobilization from intracellular stores activates and translocates PKC-α from cytosol to membrane fraction in response to STa in COLO-205 cell line. The present study was undertaken to determine the involvement of cytoskeleton proteins in translocation of PKC-α to membrane from cytosol in the Escherichiacoli STa-mediated signaling cascade in a human colonic carcinoma cell line COLO-205.Methods
Western blots and consequent densitometric analysis were used to assess time-dependent redistribution of cytoskeletal proteins. This redistribution was further confirmed by using confocal microscopy. Pharmacological reagents were applied to colonic carcinoma cells to disrupt the microfilaments (cytochalasin D) and microtubules (nocodazole).Results
STa treatment in COLO-205 cells showed dynamic redistribution and an increase in actin content in the Triton-insoluble fraction, which corresponds to an increase in polymerization within 1 min. Moreover, pharmacological disruption of actin-based cytoskeleton greatly disturbed PKC-α translocation to the membrane.Conclusions
These results suggested that the organization of actin cytoskeleton is rapidly rearranged following E. coli STa treatment and the integrity of the actin cytoskeleton played a crucial role in PKC-α movement in colonic cells. Depolymerization of tubulin had no effect on the ability of the kinase to be translocated to the membrane.General significance
In the present study, we have shown for the first time that in colonic carcinoma cells, STa-mediated rapid changes of actin cytoskeleton arrangement might be involved in the translocation of PKC-α to membrane. 相似文献83.
84.
Dobrian AD Lieb DC Ma Q Lindsay JW Cole BK Ma K Chakrabarti SK Kuhn NS Wohlgemuth SD Fontana M Nadler JL 《Biochemical and biophysical research communications》2010,403(3-4):485-490
Adipose tissue inflammation in obesity is a major factor leading to cardiovascular disease and type 2 diabetes.12/15 lipoxygenases (ALOX) play an important role in the generation of inflammatory mediators, insulin resistance and downstream immune activation in animal models of obesity. However, the expression and roles of 12/15ALOX isoforms, and their cellular sources in human subcutaneous (sc) and omental (om) fat in obesity is unknown. The objective of this study was to examine the gene expression and localization of ALOX isoforms and relevant downstream cytokines in subcutaneous (sc) and omental (om) adipose tissue in obese humans. Paired biopsies of sc and om fat were obtained during bariatric surgeries from 24 morbidly obese patients. Gene and protein expression for ALOX15a, ALOX15b and ALOX 12 were measured by real-time PCR and western blotting in adipocytes and stromal vascular fractions (SVF) from om and sc adipose tissue along with the mRNA expression of the downstream cytokines IL-12a, IL-12b, IL-6, IFNγ and the chemokine CXCL10. In a paired analysis, all ALOX isoforms, IL-6, IL-12a and CXCL10 were significantly higher in om vs. sc fat. ALOX15a mRNA and protein expression was found exclusively in om fat. All of the ALOX isoforms were expressed solely in the SVF. Further fractionation of the SVF in CD34+ and CD34- cells indicated that ALOX15a is predominantly expressed in the CD34+ fraction including vascular and progenitor cells, while ALOX15B is mostly expressed in the CD34- cells containing various leucocytes and myeloid cells. This result was confirmed by immunohistochemistry showing exclusive localization of ALOX15a in the om fat and predominantly in the vasculature and non-adipocyte cells. Our finding is identifying selective expression of ALOX15a in human om but not sc fat. This is a study showing a major inflammatory gene exclusively expressed in visceral fat in humans. 相似文献
85.
Magnesium translocation across cell membranes is essential for numerous physiological processes. Three recently reported crystal structures of the CorA magnesium transport system revealed a surprising architecture, with a bundle of giant α-helices forming a 60-Å-long pore that extends beyond the membrane before widening into a funnel-shaped cytosolic domain. The presence of divalent cations in putative intracellular regulation sites suggests that these structures correspond to the closed conformation of CorA. To examine the nature of the conduction pathway, we performed 110-ns molecular-dynamics simulations of two of these structures in a lipid bilayer with and without regulatory ions. The results show that a 15-Å-long hydrophobic constriction straddling the membrane-cytosol interface constitutes a steric bottleneck whose location coincides with an electrostatic barrier opposing cation translocation. In one of the simulations, structural relaxation after the removal of regulatory ions led to concerted changes in the tilt of the pore helices, resulting in iris-like dilation and spontaneous hydration of the hydrophobic neck. This simple and robust mechanism is consistent with the regulation of pore opening by intracellular magnesium concentration, and explains the unusual architecture of CorA. 相似文献
86.
Among different ligand binding motifs, anion binding CαNN motif consisting of peptide backbone atoms of three consecutive residues are observed to be important for recognition of free anions, like sulphate or biphosphate and participate in different key functions. Here we study the interaction of sulphate and biphosphate with CαNN motif present in different proteins. Instead of total protein, a peptide fragment has been studied keeping CαNN motif flanked in between other residues. We use classical force field based molecular dynamics simulations to understand the stability of this motif. Our data indicate fluctuations in conformational preferences of the motif residues in absence of the anion. The anion gives stability to one of these conformations. However, the anion induced conformational preferences are highly sequence dependent and specific to the type of anion. In particular, the polar residues are more favourable compared to the other residues for recognising the anion. 相似文献
87.
Xin X Chen S Khan ZA Chakrabarti S 《American journal of physiology. Endocrinology and metabolism》2007,293(4):E1036-E1044
Dysmetabolic state in diabetes may lead to augmented synthesis of extracellular matrix (ECM) proteins. In the endothelial cells, we have previously demonstrated that glucose-induced fibronectin (FN) production and that of its splice variant, EDB(+)FN, is regulated by protein kinase B (PKB, also known as Akt). In this study, we investigated the role of Akt1 in ECM protein production in the organs affected by chronic diabetic complications. We studied Akt1/PKBalpha knockout mice and wild-type control littermates. To avoid confounding effects of systemic insulin, we used 30% galactose feeding to induce hyperhexosemia for 8 wk starting at 6 wk of age. We investigated FN mRNA, EDB(+)FN mRNA, and transforming growth factor (TGF)-beta mRNA expression, Akt phosphorylation, Akt kinase activity, and NF-kappaB and AP-1 activation in the retina, heart, and kidney. Renal and cardiac tissues were histologically examined. Galactose feeding caused significant upregulation of FN, EDB(+)FN, and TGF-beta in all tissues. FN protein levels paralleled mRNA. Such upregulation were prevented in Akt1-deficient galactose-fed mice. Galactose feeding caused ECM protein deposition in the glomeruli and in the myocardium, which was prevented in the Akt knockout mice. NF-kappaB and AP-1 activation was pronounced in galactose-fed wild-type mice and prevented in the galactose-fed Akt1/PKBalpha-deficient group. In the retina and kidney, Ser473 was the predominant site for Akt phosphorylation, whereas in the heart it was Thr308. Parallel experiment in streptozotocin-induced diabetic animals showed similar results. The data from this study indicate that hyperhexosemia-induced Akt/PKB activation may be an important mechanism leading to NF-kappaB and AP-1 activation and increased ECM protein synthesis in the organs affected by chronic diabetic complications. 相似文献
88.
Lysis of human immunodeficiency virus type 1 by a specific secreted human phospholipase A2 下载免费PDF全文
Kim JO Chakrabarti BK Guha-Niyogi A Louder MK Mascola JR Ganesh L Nabel GJ 《Journal of virology》2007,81(3):1444-1450
Phospholipase A2 (PLA2) proteins affect cellular activation, signal transduction, and possibly innate immunity. A specific secretory PLA2, sPLA2-X, is shown here to neutralize human immunodeficiency virus type 1 (HIV-1) through degradation of the viral membrane. Catalytic function was required for antiviral activity, and the target cells of infection were unaffected. sPLA2-X potently reduced gene transfer of HIV-1 Env-pseudotyped lentivirus vectors and inhibited the replication of both CCR5- and CXCR4-tropic HIV-1 in human CD4+ T cells. Virions resistant to damage by antibody and complement were sensitive to lysis by sPLA2-X, suggesting a novel mechanism of antiviral surveillance independent of the acquired immune system. 相似文献
89.
T3 (3,3', 5-triiodo-L-thyronine; 20 microg/100 g body weight/day in 0.01 N NaOH, i.p for 1, 3 and 5 days) treatment modulated reduced (GSH) and oxidized (GSSG) glutathione contents along with the activities of its metabolizing enzymes (such as glutathione peroxidase, glutathione reductase and glutathione S-transferase) in the testis of Wistar rats. However, the magnitude and nature of changes in the above biochemical parameters in response to T3 treatment were noticed to be different between mitochondrial and post-mitochondrial fractions. This was accompanied with elevated levels of lipid hydroperoxide and ascorbic acid in the crude homogenate of testis. The level of hydrogen peroxide in the post-mitochondrial fractions of testes did not change on first day, decreased on 3rd day and increased on 5th day of the hormone treatment when compared to respective controls. Nevertheless, its content in mitochondria was significantly elevated in response to all the three durations of the hormone treatment having the highest induction on 3rd day. The changes observed in the levels of GSH and GSSG and its metabolizing enzymes in response to T3 treatment reflect an alteration in the redox state of testis, which may be a causative factor for the impairment of testicular physiology as a consequence of oxidative stress. 相似文献
90.
Biotechnological conversion of agro-industrial wastewaters into biodegradable plastic, poly beta-hydroxybutyrate 总被引:1,自引:0,他引:1
Khardenavis AA Suresh Kumar M Mudliar SN Chakrabarti T 《Bioresource technology》2007,98(18):3579-3584
Waste activated sludge generated from a combined dairy and food processing industry wastewater treatment plant was evaluated for its potential to produce biodegradable plastic, poly beta-hydroxybutyric acid (PHB). Deproteinized jowar grain-based distillery spentwash yielded 42.3% PHB production (w/w), followed by filtered rice grain-based distillery spentwash (40% PHB) when used as substrates. Addition of di-ammonium hydrogen phosphate (DAHP) resulted in an increase in PHB production to 67% when raw rice grain-based spentwash was used. Same wastewater, after removal of suspended solids by filtration and with DAHP supplementation resulted in lower PHB production (57.9%). However, supplementing other wastes with DAHP led to a substantial decrease in PHB content in comparison to what was observed in the absence of DAHP. 相似文献