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排序方式: 共有168条查询结果,搜索用时 421 毫秒
101.
V Pragasam P Kalaiselvi K Sumitra S Srinivasan P Anandkumar P Varalakshmi 《Biomarkers》2006,11(2):153-163
The generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in hyperoxaluric condition has been proved experimentally. This may result in the formation of the cytotoxic metabolite peroxynitrite, which is capable of causing lipid peroxidation and protein modification. The presence of nitrotyrosine in proteins has been associated with several pathological conditions. The present study investigated the presence of nitrotyrosine in the stone formers Tamm-Horsfall glycoprotein (THP). In vitro nitration of control THP was carried out using peroxynitrite. New Zealand white rabbits were immunized with peroxynitrated THP at 15-day intervals. Antisera collected following the third immunization were assayed for antibody titres using solid-phase ELISA. Antibodies were purified by affinity chromatography. The carbonyl content of control, stone formers and nitrated THP were determined. Western blotting was carried with control, stone formers and nitrated THPs. Immunodiffusion studies demonstrated cross-reaction with nitrated bovine serum albumin. Significant amounts (p < 0.001) of carbonyl content were present in both stone formers and nitrated THPs. Western blot analysis confirmed the presence of nitrated amino acid 3-nitrotyrosine in stone formers, which could bring about structural and functional modifications of THP in hyperoxaluric patients. A cross-reaction with nitrated bovine serum albumin confirms that the raised antibody has certain paratopes similar to the epitope of nitrated protein molecules. Detection of 3-nitrotyrosine in stone formers THP indicates that it is one of the key factors influencing the conversion of THP to a structurally and immunologically altered form during calcium oxalate stone formation. 相似文献
102.
Palanisamy Uma Maheswari Mallayan Palaniandavar Reji Thomas 《Inorganica chimica acta》2006,359(14):4601-4612
A series of mixed ligand Ru(II) complexes of 5,6-dimethyl-1,10-phenanthroline (5,6-dmp) as primary ligand and 1,10-phenanthroline (phen), 2,2′-bipyridine (bpy), pyridine (py) and NH3 as co-ligands have been prepared and characterized by X-ray crystallography, elemental analysis and 1H NMR and electronic absorption spectroscopy. The X-ray crystal structure of the complex [Ru(phen)2(bpy)]Cl2 reveals a distorted octahedral coordination geometry for the RuN6 coordination sphere. The DNA binding constants obtained from the absorption spectral titrations decrease in the order, tris(5,6-dmp)Ru(II) > bis(5,6-dmp)Ru(II) > mono(5,6-dmp)Ru(II), which is consistent with the trend in apparent emission enhancement of the complexes on binding to DNA. These observations reveal that the DNA binding affinity of the complexes depend upon the number of 5,6-dmp ligands and hence the hydrophobic interaction of 5,6-dimethyl groups on the DNA surface, which is critical in determining the DNA binding affinity and the solvent accessibility of the exciplex. Among the bis(5,6-dmp)Ru(II) complexes, those with monodentate py (4) or NH3 (5) co-ligands show DNA binding affinities slightly higher than the bpy and phen analogues. This reveals that they interact with DNA through the co-ligands while both the 5,6-dmp ligands interact with the exterior of the DNA surface. All these observations are supported by thermal denaturation and viscosity measurements. Two DNA binding modes - surface/electrostatic and strong hydrophobic/partial intercalative DNA interaction - are suggested for the mixed ligand complexes on the basis of time-resolved emission measurements. Interestingly, the 5,6-dmp ligands promote aggregation of the complexes on the DNA helix as a helical nanotemplate, as evidenced by induced CD signals in the UV region. The ionic strength variation experiments and competitive DNA binding studies on bis(5,6-dmp)Ru(II) complexes reveal that EthBr and the partially intercalated and kinetically inert [Ru(phen)2(dppz)]2+ (dppz = dipyrido[3,2-a:2′,3′-c]phenazine) complexes revert the CD signals induced by exciton coupling of the DNA-bound complexes with the free complexes in solution. 相似文献
103.
A highly sensitive and selective amperometric hydrogen peroxide (H(2)O(2)) biosensor based on immobilization of hemoglobin (Hb) at multiwalled carbon nanotubes-zinc oxide (MWCNT/ZnO) composite modified glassy carbon electrode (GCE) is reported. ZnO microsponges were electrochemically grown on MWCNT surface by the simple, cost-effective, green, electrochemical method at room temperature. The MWCNT/ZnO/Hb composite film showed a pair of well-defined, quasi-reversible redox peaks with a formal potential (E°') of -0.336V, characteristic features of heme redox couple of Hb. The electron transfer rate constant (k(s)) of immobilized Hb was 1.26s(-1). The developed biosensor showed a very fast response (>2s) toward H(2)O(2) with good sensitivity, wide linear range, and low detection limit of 0.02μM. The fabricated biosensor showed interesting features, including high selectivity, acceptable stability, good reproducibility, and repeatability along with excellent conductivity, facile electron mobility of MWCNT, and good biocompatibility of ZnO. The fabrication method of this biosensor is simple and effective for determination of H(2)O(2) in real samples with quick response, good sensitivity, high selectivity, and acceptable recovery. 相似文献
104.
Impact of epigallo catechin-3-gallate on acetylcholine-acetylcholine esterase cycle in aged rat brain 总被引:1,自引:0,他引:1
Neurotransmission plays an important role in communication of messages in brain. Cholinergic alterations during aging are associated with learning and memory. Neurotransmitters and enzymes that influence these neurotransmitters are significant in age-associated memory. Neurotransmitters like acetylcholine, serotonin and dopamine levels were studied. Kinetics of acetylcholine esterase was studied. There was an alteration in km and Vm values which was brought back to near-normalcy by EGCG. Behavioural changes were assessed by radial maze experiment. EGCG, a good neuroprotective drug proved to alleviate the behavioural alterations in aged rat brain. Acetylcholine esterase was partially purified from rat brain and assayed in vitro. Several modifiers like EGCG and donepezil were added in silico and the activity of the enzyme was calculated. EGCG increased the activity when compared to negative control, donepezil. Using bioinformatics tools EGCG, acetylcholine and donepezil were docked with acetylcholine esterase. EGCG formed a good docking-complex with the enzyme. Thus, it shall be hypothesized that the neuroprotective activity of EGCG might be due to its influence on cholinergic neurotransmission thereby improving the cognitive functions of the brain. 相似文献
105.
Palanisamy GS Kirk NM Ackart DF Obregón-Henao A Shanley CA Orme IM Basaraba RJ 《PloS one》2012,7(3):e34148
The typical host response to infection of humans and some animals by M. tuberculosis is the accumulation of reactive oxygen species generating inflammatory cells into discrete granulomas, which frequently develop central caseous necrosis. In previous studies we showed that infection of immunologically naïve guinea pigs with M. tuberculosis leads to localized and systemic oxidative stress that results in a significant depletion of serum total antioxidant capacity and the accumulation of malondialdehyde, a bi-product of lipid peroxidation. Here we show that in addition, the generation of excessive reactive oxygen species in vivo resulted in the accumulation of oxidized low density lipoproteins (OxLDL) in pulmonary and extrapulmonary granulomas, serum and lung macrophages collected by bronchoalveolar lavage. Macrophages from immunologically naïve guinea pigs infected with M. tuberculosis also had increased surface expression of the type 1 scavenger receptors CD36 and LOX1, which facilitate the uptake of oxidized host macromolecules including OxLDL. Vaccination of guinea pigs with Bacillus Calmette Guerin (BCG) prior to aerosol challenge reduced the bacterial burden as well as the intracellular accumulation of OxLDL and the expression of macrophage CD36 and LOX1. In vitro loading of guinea pig lung macrophages with OxLDL resulted in enhanced replication of bacilli compared to macrophages loaded with non-oxidized LDL. Overall, this study provides additional evidence of oxidative stress in M. tuberculosis infected guinea pigs and the potential role OxLDL laden macrophages have in supporting intracellular bacilli survival and persistence. 相似文献
106.
Viswanadha Vijaya Padma Chennam Srinivasulu Shyamala Devi Palaniswamy Kalaiselvi 《Biological trace element research》2010,137(3):344-352
The present study evaluated the protective effect of fish oil in isoproterenol-induced myocardial infarction in rats. The
results of the present study indicate that the IPH administration decreases the activities of membrane-bound ATPases compared
to control animals. Fish oil pretreatment brought about significant increase in the activity of these membrane-bound ATPases
in IPH (isoproterenol hydrochloride)-treated animals. Significant increase in serum potassium level with concomitant decrease
in the values of sodium, magnesium, and calcium were observed in IPH-treated rats compared to control rats, fish oil pretreatment
reversed these changes to near normal. Significant elevation of sodium and calcium levels with concomitant decrease in the
levels of potassium and magnesium were observed in the myocardial tissue of IPH-administered rats compared to control rats,
fish oil pretreatment followed by IPH administration brought these levels to near normal. The levels of lipid peroxidation
(LPO) in both serum and tissue were increased in IPH-treated rats compared with control rats, whereas pretreatment with fish
oil in IPH-treated rats maintained near-normal LPO levels. The results of the present study reveals that the pretreatment
of fish maintains the activities of membrane-bound ATPases and the mineral levels at near normal by the inhibition of lipid
peroxidation 相似文献
107.
108.
Raul Aguilar Jerry Pan Corinna Gries Inigo San Gil Giri Palanisamy 《Ecological Informatics》2010,5(1):26-31
Our team developed a metadata editing and management system employing state of the art XML technologies initially aimed at the environmental sciences but with the potential to be useful across multiple domains. We chose a modular and distributed design for scalability, flexibility, options for customizations, and the possibility to add more functionality at a later stage. The system consists of a desktop design tool that generates code for the actual online editor, a native XML database, and an online user access management application. A Java Swing application that reads an XML schema, the design tool provides the designer with options to combine input fields into online forms with user-friendly tags and determine the flow of input forms. Based on design decisions, the tool generates XForm code for the online metadata editor which is based on the Orbeon XForms engine. The design tool fulfills two requirements: First data entry forms based on a schema are customized at design time and second the tool can generate data entry applications for any valid XML schema without relying on custom information in the schema. A configuration file in the design tool saves custom information generated at design time. Future developments will add functionality to the design tool to integrate help text, tool tips, project specific keyword lists, and thesaurus services.Cascading style sheets customize the look-and-feel of the finished editor. The editor produces XML files in compliance with the original schema, however, a user may save the input into a native XML database at any time independent of validity. The system uses the open source XML database eXist for storage and uses a MySQL relational database and a simple Java Server Faces user interface for file and access management. We chose three levels to distribute administrative responsibilities and handle the common situation of an information manager entering the bulk of the metadata but leave specifics to the actual data provider. 相似文献
109.
110.
Gil IS Sheldon W Schmidt T Servilla M Aguilar R Gries C Gray T Field D Cole J Pan JY Palanisamy G Henshaw D O'Brien M Kinkel L McMahon K Kottmann R Amaral-Zettler L Hobbie J Goldstein P Guralnick RP Brunt J Michener WK 《Omics : a journal of integrative biology》2008,12(2):151-156
The Genomic Standards Consortium (GSC) invited a representative of the Long-Term Ecological Research (LTER) to its fifth workshop to present the Ecological Metadata Language (EML) metadata standard and its relationship to the Minimum Information about a Genome/Metagenome Sequence (MIGS/MIMS) and its implementation, the Genomic Contextual Data Markup Language (GCDML). The LTER is one of the top National Science Foundation (NSF) programs in biology since 1980, representing diverse ecosystems and creating long-term, interdisciplinary research, synthesis of information, and theory. The adoption of EML as the LTER network standard has been key to build network synthesis architectures based on high-quality standardized metadata. EML is the NSF-recognized metadata standard for LTER, and EML is a criteria used to review the LTER program progress. At the workshop, a potential crosswalk between the GCDML and EML was explored. Also, collaboration between the LTER and GSC developers was proposed to join efforts toward a common metadata cataloging designer's tool. The community adoption success of a metadata standard depends, among other factors, on the tools and trainings developed to use the standard. LTER's experience in embracing EML may help GSC to achieve similar success. A possible collaboration between LTER and GSC to provide training opportunities for GCDML and the associated tools is being explored. Finally, LTER is investigating EML enhancements to better accommodate genomics data, possibly integrating the GCDML schema into EML. All these action items have been accepted by the LTER contingent, and further collaboration between the GSC and LTER is expected. 相似文献