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Biochemical Study (biochemical + study)
Selected AbstractsRole Of Campylobacter Jejuni In Experimental Allergic Neuritis: A Morphological And Biochemical StudyJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001M Laura Objective: The aim of the study was to evaluate if Campylobacter jejuni (C.j.) when used as an adjuvant would be able to produce a different form of Experimental Allergic Neuritis (EAN). We present here some preliminary results. Background: EAN is considered the in vivo model of Guillain-Barrč Syndrome (GBS), which is often preceded by c.j. infection. EAN can be induced in Lewis rats by immunization with bovine peripheral nerve myelin in complete Freund's adjuvant (CFA), an emulsion formed by oil-in-water and dead mycobacteria. An adjuvant is usually necessary for the induction of EAN because it enhances the immunogenicity of the antigen. Clinically EAN is characterized by an acute monophasic course and progressive tail and limb weakness. The pathological finding is represented by marked demyelination affecting the roots and the sciatic nerve. Methods: 4 Lewis rats were immunized with an emulsion containing 2 mg of bovine peripheral myelin and C.j. strain Penner 0:41 in incomplete Freund's adjuvant (IFA). They were compared to 4 controls immunized with the same amount of peripheral myelin in CFA. The clinical course of the disease and the histological pattern of the roots and the sciatic nerve were examined. Anti-peripheral myelin, anti-C.jejuni and anti-GM1 antibodies' reactivity was detected by an ELISA assay. A biochemical study was performed to test the role of cell- and humoral-mediated responses. Results: The Lewis rats immunized with the C.j. as an adjuvant showed a delayed onset and a milder course of disease. Pathology in the roots was characterized by predominant demyelination, whereas the sciatic nerve presented very little signs of damage. Conclusion: This serotype of C.j. appears to be a less effective adjuvant in inducing EAN rather than Mycobacteria. Further studies are necessary to elucidate the pathogenetic mechanisms involved in GBS. [source] Biochemical study of resistance to imidacloprid in B biotype Bemisia tabaci from GuatemalaPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2003Frank J Byrne Abstract Systemic uptake bioassays using excised cotton leaves confirmed resistance to imidacloprid in a Guatemalan population of the tobacco whitefly Bemisia tabaci Gennadius. Polyacrylamide gel electrophoresis of naphthyl esterases identified the insects as B-types. Upon collection from the field, resistance was determined to be 58-fold relative to a susceptible strain originating in the Imperial Valley of California. Resistance levels increased to 126-fold in this population during its continuous exposure to systemically treated cotton. In biochemical investigations, there was no detectable NADPH-dependent mixed function oxidase metabolism of 14C-imidacloprid at any time during the selection process. In contrast, microsomal preparations from housefly abdomens readily produced significant amounts of the mono-hydroxy and olefin derivatives of the parent compound. Detoxification of imidacloprid by housefly MFOs may account for reports of lower toxicity of the insecticide towards this insect compared with whiteflies, despite similar binding properties between imidacloprid and the nicotinic acetylcholine receptors in both species. © 2003 Society of Chemical Industry [source] A diet enriched with mackerel (Scomber scombrus),derived products improves the endothelial function in a senior population (Prevención de las Enfermedades Cardiovasculares: Estudio Santońa , PECES project)EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2009J. R. De Berrazueta ABSTRACT Background, Regular consumption of fish reduces cardiovascular risks. Here, we investigate if the consumption of products with mackerel (Scomber scombrus) with 8·82 g of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) content per 100 g of product improves parameters of endothelial function in a controlled population. Materials and methods, Subjects maintained a 12-week diet with products with mackerel. The population consisted of 58 senior subjects (12 withdrawals, 25 women), aged 82·08 ± 8·13 years (Group A). Twenty-three senior subjects (13 women) on a regular diet were used as the control group (Group B). Subjects of Group A received 57 portions throughout 12 weeks (four to five portions a week of products with a mean EPA + DHA content of 2·5 g a day). A continuous follow-up and a final evaluation were performed to determine the level of consumption. Plasma samples were stored at ,70 °C for a biochemical study. Endothelial function was analysed by reactive hyperemia with a mercury strain gauge plethysmography with measurement of blood flow in the forearm, both baseline and at the end of the 12-week diet. Results, Endothelium-dependent vasodilatation significantly increased in Group A subjects (P < 0·001). No changes were found in Group B. The subgroup analyses showed that improvements were produced in Group A subjects without cardiovascular disease (P < 0·001). Nitrites/nitrates and von Willebrand factor plasma concentrations were higher in participants after the 12-week diet. Conclusions, The consumption of mackerel meat products improves endothelium-dependent, flow-mediated vasodilatation in a senior population. This finding might explain some of the cardioprotective effects of fish consumption. [source] Protein,protein docking dealing with the unknownJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 2 2010Irina S. Moreira Abstract Protein,protein binding is one of the critical events in biology, and knowledge of proteic complexes three-dimensional structures is of fundamental importance for the biochemical study of pharmacologic compounds. In the past two decades there was an emergence of a large variety of algorithms designed to predict the structures of protein,protein complexes,a procedure named docking. Computational methods, if accurate and reliable, could play an important role, both to infer functional properties and to guide new experiments. Despite the outstanding progress of the methodologies developed in this area, a few problems still prevent protein,protein docking to be a widespread practice in the structural study of proteins. In this review we focus our attention on the principles that govern docking, namely the algorithms used for searching and scoring, which are usually referred as the docking problem. We also focus our attention on the use of a flexible description of the proteins under study and the use of biological information as the localization of the hot spots, the important residues for protein,protein binding. The most common docking softwares are described too. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [source] Biochemical characterization of human glutamate carboxypeptidase IIIJOURNAL OF NEUROCHEMISTRY, Issue 3 2007Klára Hlouchová Abstract Human glutamate carboxypeptidase II (GCPII) is a transmembrane metallopeptidase found mainly in the brain, small intestine, and prostate. In the brain, it cleaves N -acetyl- l -aspartyl-glutamate, liberating free glutamate. Inhibition of GCPII has been shown to be neuroprotective in models of stroke and other neurodegenerations. In prostate, it is known as prostate-specific membrane antigen, a cancer marker. Recently, human glutamate carboxypeptidase III (GCPIII), a GCPII homolog with 67% amino acid identity, was cloned. While GCPII is recognized as an important pharmaceutical target, no biochemical study of human GCPIII is available at present. Here, we report the cloning, expression, and characterization of recombinant human GCPIII. We show that GCPIII lacks dipeptidylpeptidase IV-like activity, its activity is dependent on N -glycosylation, and it is effectively inhibited by several known inhibitors of GCPII. In comparison to GCPII, GCPIII has lower N -acetyl- l -aspartyl-glutamate-hydrolyzing activity, different pH and salt concentration dependence, and distinct substrate specificity, indicating that these homologs might play different biological roles. Based on a molecular model, we provide interpretation of the distinct substrate specificity of both enzymes, and examine the amino acid residues responsible for the differences by site-directed mutagenesis. These results may help to design potent and selective inhibitors of both enzymes. [source] Neuroradiologic Evidence of Pre-Synaptic and Post-Synaptic Nigrostriatal Dopaminergic Dysfunction in Idiopathic Basal Ganglia Calcification: A Case ReportJOURNAL OF NEUROIMAGING, Issue 2 2010Takahiro Saito MD ABSTRACT Idiopathic basal ganglia calcification (IBGC) is a neuropathological condition known to manifest as motor disturbance, cognitive impairment, and psychiatric symptoms. The pathophysiology of the psychiatric symptoms of IBGC, however, remains controversial. A previous biochemical study suggested that dopaminergic impairment is involved in IBGC. We thus hypothesized that dopaminergic dysfunction might be related with the psychiatric manifestations of IBGC. We used positron emission tomography to measure glucose metabolism and dopaminergic function in the basal ganglia of an IBGC patient with psychiatric symptoms. The results showed that widespread hypometabolism was evident in the frontal, temporal, and parietal cortices while the decline in dopaminergic function was severe in the bilateral striatum. The functional decline of the dopamine system in the calcified area of the bilateral striatum and the disruption of cortico-subcortical circuits may contribute to clinical manifestations of IBGC in our patient. [source] C-terminal region-dependent change of antibody-binding to the Eighth Reelin repeat reflects the signaling activity of ReelinJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2009Takao Kohno Abstract Reelin is a secreted glycoprotein that plays pivotal roles in the development and function of the brain, but how it activates downstream intracellular signaling is not fully understood. We have recently reported that the highly conserved C-terminal region (CTR) of Reelin is required for its full signaling activity, although the underlying mechanism remains unknown. During biochemical study of Reelin, we serendipitously found that one commercially available anti-Reelin antibody G20 can bind to CTR-lacking mutant Reelin proteins, but not wild-type Reelin, on Western blotting. The G20 epitope resides in the last 19 residues of Reelin-repeat 8 (RR8), and neither posttranslational modification nor proteolysis can explain this effect. Furthermore, when an unrelated sequence, such as FLAG-tag, is inserted between RR8 and CTR, the reactivity of the corresponding antibody greatly decreases. These results suggest that RR8 and CTR form a tight structure that makes the surrounding sequence inaccessible to an antibody. Taking advantage of this phenomenon, we show the existence of CTR-lacking Reelin isoform in vivo for the first time and estimate its contribution to the total amount of secreted Reelin. Importantly, the extent to which Reelin mutants react with G20 is inversely correlated with their signaling activity, indicating that the CTR-induced structural change of RR8 is a prerequisite for downstream signaling activation, presumably via binding to a certain neuronal membrane molecule(s). © 2009 Wiley-Liss, Inc. [source] Role Of Campylobacter Jejuni In Experimental Allergic Neuritis: A Morphological And Biochemical StudyJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001M Laura Objective: The aim of the study was to evaluate if Campylobacter jejuni (C.j.) when used as an adjuvant would be able to produce a different form of Experimental Allergic Neuritis (EAN). We present here some preliminary results. Background: EAN is considered the in vivo model of Guillain-Barrč Syndrome (GBS), which is often preceded by c.j. infection. EAN can be induced in Lewis rats by immunization with bovine peripheral nerve myelin in complete Freund's adjuvant (CFA), an emulsion formed by oil-in-water and dead mycobacteria. An adjuvant is usually necessary for the induction of EAN because it enhances the immunogenicity of the antigen. Clinically EAN is characterized by an acute monophasic course and progressive tail and limb weakness. The pathological finding is represented by marked demyelination affecting the roots and the sciatic nerve. Methods: 4 Lewis rats were immunized with an emulsion containing 2 mg of bovine peripheral myelin and C.j. strain Penner 0:41 in incomplete Freund's adjuvant (IFA). They were compared to 4 controls immunized with the same amount of peripheral myelin in CFA. The clinical course of the disease and the histological pattern of the roots and the sciatic nerve were examined. Anti-peripheral myelin, anti-C.jejuni and anti-GM1 antibodies' reactivity was detected by an ELISA assay. A biochemical study was performed to test the role of cell- and humoral-mediated responses. Results: The Lewis rats immunized with the C.j. as an adjuvant showed a delayed onset and a milder course of disease. Pathology in the roots was characterized by predominant demyelination, whereas the sciatic nerve presented very little signs of damage. Conclusion: This serotype of C.j. appears to be a less effective adjuvant in inducing EAN rather than Mycobacteria. Further studies are necessary to elucidate the pathogenetic mechanisms involved in GBS. [source] Fipronil resistance in the whitebacked planthopper (Sogatella furcifera): possible resistance mechanisms and cross-resistancePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2010Jian Tang Abstract BACKGROUND: The whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), is a major rice pest in many parts of Asia. Fipronil has been widely used to control rice pests, and resistance to fipronil has been reported in some important species. RESULTS: A field population (F) of WBPH was collected, with 50.5-fold resistance to fipronil, which increased to 137.5-fold (F-se) after continuous selection for 11 generations. The F-se population did not show significant cross-resistance to the insecticides examined by comparison with the F population. TPP (synergism ratio 1.9), DEM (1.5) and PBO (1.1) showed only slight synergism on fipronil in the F-se population. A large increase was found in esterase and P450 monooxygenase activity in the F-se population. In vitro, PBO inhibited both esterase and P450 monooxygenase activity, and TPP inhibited esterase activity in the F-se population. CONCLUSION: Synergistic study in vivo and biochemical study in vitro indicated that esterase and P450 monooxygenases might be important factors for fipronil resistance in the selected population F-se. However, these biochemical factors could not lead to such high resistance (137.5-fold) in the F-se population, and target-site insensitivity would be another or more important factor. Copyright © 2009 Society of Chemical Industry [source] | ||||||||||||||||