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排序方式: 共有1004条查询结果,搜索用时 31 毫秒
111.
Ritu Tyagi Poonam Rana Mamta Gupta Ahmad Raza Khan M. Memita Devi Deepak Bhatnagar Raja Roy Rajendra P. Tripathi Subash Khushu 《Metabolomics : Official journal of the Metabolomic Society》2012,8(5):940-950
The metabolomic approach has been widely used in toxicology to investigate mechanisms of toxicity. To understand the mammalian system??s response to nickel exposure, we analysed the NiCl2 induced metabolomic changes in urine of rats using 1H nuclear magnetic resonance (1H NMR) spectroscopy together with clinically relevant biochemical parameters. Male Sprague?CDawley rats were administered intraperitoneally with NiCl2 at doses of 4, 10 and 20?mg/kg body weight. Urine samples were collected at 8, 16, 24, 72, 96 and 120?h post treatment. The metabolomic profile of rat urine showed prominent changes in citrate, dimethylamine, creatinine, choline, trimethylamine oxide (TMAO), phenyl alanine and hippurate at all doses. Principal component analysis of urine 1H NMR spectra demonstrated the dose and time dependent development of toxicity. The metabolomic time trajectory, based on pattern recognition analysis of 1H NMR spectra of urine, illustrated clear separation of pre and post treatments (temporal). Only animals treated with a low dose of NiCl2 returned to normal physiology. The 1H NMR spectral data correlated well with the clinically relevant nephrotoxic biomarkers. The urinary metabolomic phenotyping for NiCl2 induced nephrotoxicity was defined according to the predictive ability of the known metabolite biomarkers, creatinine, citrate and TMAO. The current approach demonstrates that metabolomics, one of the most important platform in system biology, may be a promising tool for identifying and characterizing biochemical responses to toxicity. 相似文献
112.
In plants, auxin-mediated responses are regulated by diverse proteins. One such class of proteins, i.e. GH3, is involved in
the conjugation of IAA to amino acids and provides a negative feedback loop to control auxin homoeostasis. In order to have
a better understanding of the mechanism of the auxin action, 15 genes encoding GH3 members were identified using existing
EST databases of tomato. Their orthologs were identified from tobacco, potato, N. benthemiana, pepper, and petunia. Phylogenetic analysis of AtGH3, SlGH3, and their Solanaceae orthologs provided insights into various orthologous relationships among these proteins. These genes
were found to be responsive to a variety of signals including, phytohormones and environmental stresses. Analysis of AuxRE
elements in their promoters showed variability in the sequence as well as number of this element. Up-regulation of only 11
SlGH3 genes, in response to exogenous auxin, suggested possible relationship between the diversity in the sequence and number
of AuxRE element with the auxin inducibility. Expression analysis of SlGH3 genes in different vegetative and reproductive tissues/stages suggested limited or no role for most of the SlGH3 genes at the initiation of fruit ripening. However, up-regulation of SlGH3-1 and -2 at the onset of fruit ripening indicates that these genes could have a role in fruit ripening. The present study characterizes
GH3 gene family of tomato and its evolutionary relationship with members of this family from other Solanaceae species and Arabidopsis. It could help in the identification of GH3 genes and revelation of their function during vegetative/reproductive development stages from other Solanaceae members. 相似文献
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115.
Pearson R Kim YK Hokello J Lassen K Friedman J Tyagi M Karn J 《Journal of virology》2008,82(24):12291-12303
116.
Ruchi Jain Bappaditya Dey Neeraj Dhar Vivek Rao Ramandeep Singh Umesh D. Gupta V. M. Katoch V. D. Ramanathan Anil K. Tyagi 《PloS one》2008,3(12)
Background
The variable efficacy (0–80%) of Mycobacterium bovis Bacille Calmette Guréin (BCG) vaccine against adult tuberculosis (TB) necessitates development of alternative vaccine candidates. Development of recombinant BCG (rBCG) over-expressing promising immunodominant antigens of M. tuberculosis represents one of the potential approaches for the development of vaccines against TB.Methods/Principal Findings
A recombinant strain of BCG - rBCG85C, over expressing the antigen 85C, a secretory immuno-dominant protein of M. tuberculosis, was evaluated for its protective efficacy in guinea pigs against M. tuberculosis challenge by aerosol route. Immunization with rBCG85C resulted in a substantial reduction in the lung (1.87 log10, p<0.01) and spleen (2.36 log10, p<0.001) bacillary load with a commensurate reduction in pathological damage, when compared to the animals immunized with the parent BCG strain at 10 weeks post-infection. rBCG85C continued to provide superior protection over BCG even when post-challenge period was prolonged to 16 weeks. The cytokine profile of pulmonary granulomas revealed that the superior protection imparted by rBCG85C was associated with the reduced levels of pro-inflammatory cytokines - interleukin (IL)-12, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, moderate levels of anti-inflammatory cytokine - transforming growth factor (TGF)-β along with up-regulation of inducible nitric oxide synthase (iNOS). In addition, the rBCG85C vaccine induced modulation of the cytokine levels was found to be associated with reduced fibrosis and antigen load accompanied by the restoration of normal lung architecture.Conclusions/Significance
These results clearly indicate the superiority of rBCG85C over BCG as a promising prophylactic vaccine against TB. The enduring protection observed in this study gives enough reason to postulate that if an open-ended study is carried out with low dose of infection, rBCG85C vaccine in all likelihood would show enhanced survival of guinea pigs. 相似文献117.
Moshal KS Zeldin DC Sithu SD Sen U Tyagi N Kumar M Hughes WM Metreveli N Rosenberger DS Singh M Vacek TP Rodriguez WE Ayotunde A Tyagi SC 《Journal of cellular physiology》2008,215(3):771-781
Hyperhomocysteinemia (HHcy) is associated with atherosclerotic events involving the modulation of arachidonic acid (AA) metabolism and the activation of matrix metalloproteinase-9 (MMP-9). Cytochrome P450 (CYP) epoxygenase-2J2 (CYP2J2) is abundant in the heart endothelium, and its AA metabolites epoxyeicosatrienoic acids (EETs) mitigates inflammation through NF-kappabeta. However, the underlying molecular mechanisms for MMP-9 regulation by CYP2J2 in HHcy remain obscure. We sought to determine the molecular mechanisms by which P450 epoxygenase gene transfection or EETs supplementation attenuate homocysteine (Hcy)-induced MMP-9 activation. CYP2J2 was over-expressed in mouse aortic endothelial cells (MAECs) by transfection with the pcDNA3.1/CYP2J2 vector. The effects of P450 epoxygenase transfection or exogenous supplementation of EETs on NF-kappabeta-mediated MMP-9 regulation were evaluated using Western blot, in-gel gelatin zymography, electromobility shift assay, immunocytochemistry. The result suggested that Hcy downregulated CYP2J2 protein expression and dephosphorylated PI3K-dependent AKT signal. Hcy induced the nuclear translocation of NF-kappabeta via downregulation of IKbetaalpha (endogenous cytoplasmic inhibitor of NF-kappabeta). Hcy induced MMP-9 activation by increasing NF-kappabeta-DNA binding. Moreover, P450 epoxygenase transfection or exogenous addition of 8,9-EET phosphorylated the AKT and attenuated Hcy-induced MMP-9 activation. This occurred, in part, by the inhibition of NF-kappabeta nuclear translocation, NF-kappabeta-DNA binding and activation of IKbetaalpha. The study unequivocally suggested the pivotal role of EETs in the modulation of Hcy/MMP-9 signal. 相似文献
118.
Abdessalem Yezza Rajeshwar D. Tyagi José R. Valéro Rao Y. Surampalli 《World journal of microbiology & biotechnology》2005,21(8-9):1549-1558
Summary In this investigation, ammonium hydroxide and acetic acid were used as pH control agents during Bacillus thuringiensis (Bt) fermentation in a pilot scale fermentor (150-l) employing two secondary wastewater sludges from two different wastewater
treatment plants (CUQS and JQS) and semi-synthetic soybean meal medium as raw materials. Regardless of the cultivation medium,
a substantial increase in total cell count, spore count, protease activity and entomotoxicity was achieved when the pH of
the culture was controlled using NH4OH/CH3COOH. At harvest, total cell count increased by almost 17%, 33% and 25%; protease activity was enhanced by 12%, 33% and 53%
and maximal spore count augmented by almost 28%, 48% and 33% in CUQS, JQS and soybean medium, respectively. Entomotoxicity
potency was improved by 22%, 21% and 14% in CUQS, JQS and soybean medium, respectively compared to results obtained with NaOH/H2SO4 as pH control agents. A higher entomotoxicity was also observed using sludge compared to the soybean medium. This improvement
of the Bt process performance was a consequence of the addition of rapidly utilizable carbon and nitrogen source through pH
control, which stimulated endotoxin production in the crystal and enhanced sporulation. 相似文献
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120.
Imidazolonepropionase (HutI) (imidazolone-5-propanote hydrolase, EC 3.5.2.7) is a member of the amidohydrolase superfamily and catalyzes the conversion of imidazolone-5-propanoate to N-formimino-L-glutamate in the histidine degradation pathway. We have determined the three-dimensional crystal structures of HutI from Agrobacterium tumefaciens (At-HutI) and an environmental sample from the Sargasso Sea Ocean Going Survey (Es-HutI) bound to the product [ N-formimino-L-glutamate (NIG)] and an inhibitor [3-(2,5-dioxoimidazolidin-4-yl)propionic acid (DIP)], respectively. In both structures, the active site is contained within each monomer, and its organization displays the landmark feature of the amidohydrolase superfamily, showing a metal ligand (iron), four histidines, and one aspartic acid. A catalytic mechanism involving His265 is proposed on the basis of the inhibitor-bound structure. This mechanism is applicable to all HutI forms. 相似文献