| disposable tyrosinase-peroxidase bi-enzyme sensor for amperometric detection of phenols. | a new disposable amperometric bi-enzyme sensor system for detecting phenols has been developed. the phenol sensor developed uses horseradish peroxidase modified screen-printed carbon electrodes (hrp-spces) coupled with immobilized tyrosinase prepared using poly(carbamoylsulfonate) (pcs) hydrogels or a poly(vinyl alcohol) bearing styrylpyridinium groups (pva-sbq) matrix. optimization of the experimental parameters has been performed with regard to buffer composition, ph, operating potential and s ... | 2002 | 12392951 |
| hydrogen peroxide sensitive amperometric biosensor based on horseradish peroxidase entrapped in a polypyrrole electrode. | the enzyme horseradish peroxidase (hrp) has been entrapped in situ by electropolymerization of pyrrole onto a platinum electrode. the latter was previously coated by a polypyrrole layer for better adhesion of the biocatalyst film and in order to avoid the enzyme folding onto the pt electrode. the biosensor allowed the determination of hydrogen peroxide in the concentration range comprised between 4.9 x 10(-7) and 6.3 x 10(-4) m. the biosensor retained more than 90% of its original activity after ... | 2002 | 12392940 |
| immobilization of peroxidase glycoprotein on gold electrodes modified with mixed epoxy-boronic acid monolayers. | the development of bioelectronic enzyme applications requires the immobilization of active proteins onto solid or colloidal substrates such as gold. coverage of the gold surface with alkanethiol self-assembled monolayers (sams) reduces nonspecific adsorption of proteins and also allows the incorporation onto the surface of ligands with affinity for complementary binding sites on native proteins. we present in this work a strategy for the covalent immobilization of glycosylated proteins previousl ... | 2002 | 12392431 |
| cleavage of supercoiled dna by horseradish peroxidase plus tert-butyl hydroperoxide is not due to tert-butylperoxyl radicals. | two supercoiled (sc), double-stranded dnas, pbr 322 and puc 19, have been subjected to oxidative stress using horseradish peroxidase (hrp) and hrp + tert-butyl hydroperoxide (booh). hrp alone causes single-strand cleavage of these sc dnas. strand cleavage is enhanced substantially in the presence of commercial booh (which contains h(2)o(2)) but is, at best, only very slightly enhanced in the presence of pure booh. in the hrp/pure booh system, the dna single-strand-scission which does occur appea ... | 2002 | 12387632 |
| electroanalysis of metabolic flux from single cells in simple picoliter-volume microsystems. | a picoliter-volume electrochemical analytical chamber has been developed for detecting the metabolic flux resulting from the stress responses of a single plant cell. electrochemical cells, with volumes as small as 100 pl, were fabricated by controlled electrochemical dissolution of a gold wire sealed in glass (the back-etching of the metal realizing an ultralow-volume titer chamber). in the first instance, the electrode contained within the chamber was characterized by the microinjection of stan ... | 2002 | 12380823 |
| linker-assisted immunoassay and liquid chromatography/mass spectrometry for the analysis of glyphosate. | a novel, sensitive, linker-assisted enzyme-linked immunosorbent assay (l'elisa) was compared to on-line solid-phase extraction (spe) with high-performance liquid chromatography/mass spectrometry (hplc/ms) for the analysis of glyphosate in surface water and groundwater samples. the l'elisa used succinic anhydride to derivatize glyphosate, which mimics the epitotic attachment of glyphosate to horseradish peroxidase hapten. thus, l'elisa recognized the derivatized glyphosate more effectively (detec ... | 2002 | 12380816 |
| posterior parietal cortex projections to the ventral lateral and some association thalamic nuclei in macaca mulatta. | the study focused on projections from the posterior parietal cortex (ppc) to the ventral lateral thalamic nucleus (vl) and three thalamic association nuclei, mediodorsal (md), lateral posterior (lp) and pulvinar. for light microscopic analysis small biotinylated dextran amine (bda) or biocytin injections were placed in midrostral and dorsal portions of the inferior parietal lobule (ipl), respectively. the distribution of anterograde and retrograde labeling was charted, and representative axons a ... | 2002 | 12379444 |
| a field test for the detection of peroxide-based explosives. | a rapid and simple field test for the detection of triacetone-triperoxide (tatp) and hexamethylenetriperoxidediamine (hmtd), two explosives which find significant illegal use, has been developed. unknown samples are first treated with a catalase solution to remove hydrogen peroxide traces, in order to provide selectivity towards peroxide-based bleaching agents which are contained in commercial laundry detergents. subsequently, the peroxide-based explosives are decomposed via uv irradiation, thus ... | 2002 | 12375834 |
| detection of retrogradely transported wga-hrp in axotomized adult hamster facial motoneurons occurs after initiation of the axon reaction. | we have previously shown that facial nerve transection at the stylomastoid foramen activates ribosomal rna transcription in injured facial motoneurons (fmn) of the adult hamster within 30 minutes postoperative. the signal for the initiation of the nerve cell body response to injury in vertebrates is currently unknown. it has been hypothesized that the signal for initiating the injury response is dependent on retrograde transport, where the signal itself is either the loss of a repressor substanc ... | 2001 | 12373098 |
| mechanism-based irreversible inactivation of horseradish peroxidase at 500 mpa. | the effects of high-pressure treatment on the reaction rates of horseradish peroxidase (hrp) with guaethol or guaiacol as a hydrogen donor were evaluated from direct transmission measurements in a high-pressure optical cell at 435 nm. peroxidases are known to be very barostable and insensitive to heat. with guaethol the reaction velocity was independent of pressure up to 500 mpa, but with guaiacol the cytochrome c oxidase underwent a mechanism-based irreversible inhibition of catalytic activity ... | 2013 | 12363360 |
| structural analysis of the two horseradish peroxidase catalytic residue variants h42e and r38s/h42e: implications for the catalytic cycle. | the crystal structures of horseradish peroxidase c (hrpc) active-site mutants h42e and r38s/h42e co-crystallized with benzhydroxamic acid (bha) and ferulic acid (fa), respectively, have been solved. the 2.5 a crystal structure of the h42e-bha complex reveals that the side-chain o atoms of glu42 occupy positions that are very similar to the positions of the two side-chain n atoms of the distal histidine in the wild-type hrpc-bha structure. the mutation disturbs the hydrogen-bonding network extend ... | 2002 | 12351824 |
| hydrogel-based microreactors as a functional component of microfluidic systems. | a simple two-step method for fabricating poly(ethylene glycol) (peg) hydrogel-based microreactors and microsensors within microfluidic channels is described. the intrachannel micropatches contain either a dye, which can report the ph of a solution within a fluidic channel, or enzymes that are able to selectively catalyze specific reactions. analytes present within the microfluidic channel are able to diffuse into the micropatches, encounter the enzymes, and undergo conversion to products, and th ... | 2002 | 12349966 |
| liposome immunoblotting assay using a substrate-forming precipitate inside immunoliposomes. | a new immunoblotting assay which uses antibody-coupled liposomes containing horseradish peroxidase is proposed. a substrate 4-chloro-1-naphthol permeated through the phospholipid membrane of the antibody-coupled liposomes and formed a colored product precipitating inside the liposomes. the precipitates accumulated in the liposomes and could be detected at the positions where the liposomes coupled with a target in blotted samples. combination of liposomes with average diameter of 350 nm and a pvd ... | 2002 | 12325149 |
| 15n nmr investigation of the covalent binding of reduced tnt amines to soil humic acid, model compounds, and lignocellulose. | the five major reductive degradation products of tnt-4adnt (4-amino-2,6-dinitrotoluene), 2adnt (2-amino-4,6-dinitrotoluene), 2,4dant (2,4-diamino-6-nitrotoluene), 2,6dant (2,6-diamino-4-nitrotoluene), and tat (2,4,6-triaminotoluene)-labeled with 15n in the amine positions, were reacted with the ihss soil humic acid and analyzed by 15n nmr spectrometry. in the absence of catalysts, all five amines underwent nucleophilic addition reactions with quinone and other carbonyl groups in the soil humic a ... | 2002 | 12322752 |
| spontaneous deposition of horseradish peroxidase into polyelectrolyte multilayer capsules to improve its activity and stability. | horseradish peroxidase (hrp) was encapsulated in preformed polyelectrolyte multilayer (pem) microcapsules by spontaneous deposition with remarkably improved stability and catalytic activity. | 2002 | 12271678 |
| amperometric enzyme electrode for organic peroxides determination prepared from horseradish peroxidase immobilized in poly(vinylferrocenium) film. | organic peroxides, t-butyl hydroperoxide, 2-butanone peroxide, cumene hydroperoxide and t-butyl peracetate, were determined by an amperometric enzyme electrode. the enzyme electrode was prepared through electrostatic immobilization of horseradish peroxidase (hrp) in a polyvinylferrocenium (pvf) film. a pvf(+)clo(4)(-) film was coated on a pt foil at +0.70 v by electrooxidation of polyvinylferrocene in methylene chloride with 0.1 m tetrabutylammonium perchlorate (tbap). the enzyme modified electr ... | 2002 | 12243906 |
| the activation of molecular oxygen by horseradish peroxidase with sodium sulfite. | horseradish peroxidase (hrp) utilizes molecular oxygen (o2) with sodium sulfite (na2so3) to oxidize thioanisole and styrene at the exterior of the heme pocket. | 2001 | 12240428 |
| screen printing of nucleic acid detecting carbon electrodes. | a large fraction of the presently mass-manufactured (> 10(8) units/year) electrochemical biosensors, used mostly by diabetic people to monitor their blood glucose levels, have screen-printed carbon working electrodes. an earlier study (campbell, c. n., et al. anal. chem. 2002, 74, 158-162) showed that nucleic acids can be assayed at 1 nm concentrations by a sandwich-type amperometric method. the assay was performed with vitreous carbon working electrodes on which an electron-conducting polycatio ... | 2002 | 12236344 |
| low doses of the endocrine disruptor bisphenol-a and the native hormone 17beta-estradiol rapidly activate transcription factor creb. | endocrine-disrupting chemicals (edcs) are hormone-like agents present in the environment that alter the endocrine system of wildlife and humans. most edcs have potencies far below those of the natural hormone 17beta-e2 when acting through the classic estrogen receptors (ers). here, we show that the environmental estrogen bisphenol-a and the native hormone 17beta-e2 activate the transcription factor, camp-responsive element binding protein (creb) with the same potency. phosphorylated creb (p-creb ... | 2002 | 12207000 |
| reduction of early thalamic input alters adult corticocortical connectivity. | the functional specificity of mammalian isocortex requires that precise connections be established between cortical areas and their targets. while recent studies of cortical development have focused on intrinsic specification, the role of extrinsic factors has received considerably less attention. in the present study, we examined how early removal of thalamic input affects the development of visual corticocortical connections. hamster pups received ablations of visual thalamic nuclei on the day ... | 2002 | 12234656 |
| enzymatic degradation of 2,6-dichlorophenol by horseradish peroxidase: uv-visible and mass spectrometry characterization of the reaction products [corrected]. | the reaction mechanism of the oxidation of 2,6-dichlorophenol (2,6-dcp) by horseradish peroxidase (hrp) and h2o2 has been investigated and the reaction products have been characterized by uv-visible and mass spectrometry. evidence for the dimerization of 2,6-dcp to 3,3',5,5'-tetrachloro-4,4'-dihydroxybiphenyl and the subsequent fast oxidation of this product to the corresponding 3,3',5,5'-tetrachlorodiphenoquinone have been collected. the reaction rate was found to decrease markedly as soon as t ... | 2002 | 12230990 |
| influence of the distal his in imparting imidazolate character to the proximal his in heme peroxidase: (1)h nmr spectroscopic study of cyanide-inhibited his42-->ala horseradish peroxidase. | the functional higher oxidation states of heme peroxidases have been proposed to be stabilized by the significant imidazolate character of the proximal his. this is induced by a "push-pull" combination effect produced by the proximal asp that abstracts ("pulls") the axial his ring n(delta)h, along with the distal protonated his that contributes ("pushes") a strong hydrogen bond to the distal ligand. the molecular and electronic structure of the distal his mutant of cyanide-inhibited horseradish ... | 2002 | 12224950 |
| synthesis and gelation of dopa-modified poly(ethylene glycol) hydrogels. | 3,4-dihydroxyphenylalanine (dopa) residues are known for their ability to impart adhesive and curing properties to mussel adhesive proteins. in this paper, we report the preparation of linear and branched dopa-modified poly(ethylene glycol)s (peg-dopas) containing one to four dopa endgroups. gel permeation chromatography-multiple-angle laser light scattering analysis of methoxy-peg-dopa in the presence of oxidizing reagents (sodium periodate, horseradish peroxidase, and mushroom tyrosinase) reve ... | 2015 | 12217051 |
| stabilization of activity of oxidoreductases by their immobilization onto special functionalized glass and novel aminocellulose film using different coupling reagents. | glucose oxidase (god), horseradish peroxidase (hrp), and lactate oxidase (lod) were covalently immobilized on special nh(2)-functionalized glass and on a novel nh(2)-cellulose film via 13 different coupling reagents. the properties of these immobilized enzymes, such as activity, storage stability, and thermostability, are strongly dependent on the coupling reagent. for example, god immobilized by cyanuric chloride on the nh(2)-cellulose film loses approximately half of its immobilized activity a ... | 2012 | 12217049 |
| formation and decay of hydroperoxo-ferric heme complex in horseradish peroxidase studied by cryoradiolysis. | using radiolytic reduction of the oxy-ferrous horseradish peroxidase (hrp) at 77 k, we observed the formation and decay of the putative intermediate, the hydroperoxo-ferric heme complex, often called "compound 0." this intermediate is common for several different enzyme systems as the precursor of the compound i (ferryl-oxo pi-cation radical) intermediate. epr and uv-visible absorption spectra show that protonation of the primary intermediate of radiolytic reduction, the peroxo-ferric complex, t ... | 2002 | 12215454 |
| capillary electrophoretic enzyme immunoassay with electrochemical detection for cortisol. | a novel capillary electrophoretic enzyme immunoassay with electrochemical detection has been developed and used for the determination of cortisol. in this method, after the competitive enzyme immunoreaction, the free enzyme (horseradish peroxidase, hrp)-labeled cortisol (hrp-cortisol) and the bound enzyme-labeled cortisol (hpr-cortisol-anti-cortisol) were separated in the separation capillary and then catalyzed the enzyme substrate [3,3,5,5-tetramethyl-benzidine dihydrochloride, tmb(red)] in the ... | 2002 | 12214693 |
| increased nitric oxide-dependent nitrosylation of 4,5-diaminofluorescein by oxidants: implications for the measurement of intracellular nitric oxide. | 4,5 diaminofluorescein (daf-2) is increasingly utilized as a fluorescent detector for nitric oxide (*no) in cells and tissues. in oxygenated solutions, reactive nitrogen species derived from (*) no autoxidation nitrosate daf-2 to yield the highly fluorescent daf-2 triazole. in the present study, we investigated the nitrosation of daf-2 at a neutral ph by absorption and fluorescence spectroscopy using nonoates as chemical sources of (*) no. we found that both chemically synthesized peroxynitrite ... | 2002 | 12208354 |
| central projections of the utricular nerve in the gerbil. | the central projections of primary afferent fibers in the utricular nerve, which convey linear head acceleration signals to neurons in the brainstem and cerebellum, are not completely defined. the purpose of this investigation was twofold: 1) to define the central projections of the gerbil utricular afferents by injecting horseradish peroxidase (hrp) and biotinylated dextran amine (bda) into the utricular macula; and 2) to investigate the projections of individual utricular afferents by injectin ... | 2002 | 12205706 |
| scanning electrochemical microscopy. 44. imaging of horseradish peroxidase immobilized on insulating substrates. | scanning electrochemical microscopy (secm) was used to study horseradish peroxidase (hrp) immobilized with copolymer on insulating substrates (glass slide or polycarbonate membrane filter). two methods were used to immobilize hrp: in the first, hrp was coimmobilized by cross-linking on a glass slide with a copolymer swelled in water to form a hydrogel; in the second, the same copolymer and avidin were coimmobilized on the glass slide and biotin-labeled hrp was conjugated to the avidin of the fil ... | 2002 | 12199567 |
| non-oxidative decarboxylation of glycine derivatives by a peroxidase. | under anaerobic, peroxide-free conditions (ph 5.5, 25 degrees c), horseradish peroxidase (hrp) catalyzes the rapid, non-oxidatve decarboxylation of n-alkyl-n-phenylglycine derivatives to the corresponding n-alkyl-n-methylanilines in 100% yield. when the reaction is conducted in d2o buffer, the product contains a single deuterium in the methyl group. the reactions are very fast compared to the oxidative decarboxylation of the same substrates under standard peroxidatic conditions (i.e., hydrogen p ... | 2002 | 12188659 |
| halogenated indole-3-acetic acids as oxidatively activated prodrugs with potential for targeted cancer therapy. | substituted indole-3-acetic acid (iaa) derivatives, plant auxins with potential for use as prodrugs in enzyme-prodrug directed cancer therapies, were oxidised with horseradish peroxidase (hrp) and toxicity against v79 chinese hamster lung fibroblasts was determined. rate constants for oxidation by hrp compound i were also measured. halogenated iaas were found to be the most cytotoxic, with typical surviving fractions of <10(-3) after incubation for 2h with 100 microm prodrug and hrp. | 2002 | 12182852 |
| development and application of an enzyme immunoassay based on a monoclonal antibody against gonyautoxin components of paralytic shellfish poisoning toxins. | with a gonyautoxin 2/3 (gtx2/3)-specific monoclonal antibody (designated gt-13a) and a saxitoxin-horseradish peroxidase conjugate (stx-hrp), a direct competitive enzyme immunoassay (gtx-eia) was established and its sensitivity to various toxin components was investigated. the concentrations resulting in 50% inhibition of the binding of stx-hrp to the solid-phase gt-13a antibody for gtx2/3, decarbamoyl-gtx2/3 (dc-gtx2/3), n-sulfocarbamoyl-gtx2/3 (c1/2), gtx1/4, stx, and neosaxitoxin (neostx) in g ... | 2002 | 12182484 |
| continuous on-line measurement of cerebral hydrogen peroxide using enzyme-modified ring-disk plastic carbon film electrode. | an amperometric method suitable for the continuous on-line measurement of cerebral hydrogen peroxide from a microdialysate has been successfully performed for the first time by using an enzyme-modified ring-disk plastic carbon film electrode (pcfe) in a thin-layer radial flow cell. pcfe consists of a ring electrode modified with horseradish peroxidase to detect h2o2 at 0.0 v (vs ag/ agcl) and a disk electrode coated with ascorbate oxidase (aox) to preoxidize ascorbic acid (aa) and thus suppress ... | 2002 | 12175154 |
| the effect of reversed micelles on horseradish peroxidase (hrp) structure and function. | effects of water content (w(0)) and surfactants on the activity of hrp in ctab/isooctane-n-pentanol reversed micelles were investigated. based on uv-vis spectroanalysis and the activity of hrp at various w(0) and ctab content, it was found that the active-site of hrp was mainly influenced by reversed micelles. however, ctab had no effect on the active-site of hrp. in addition, the stabilities and soret band of hrp-h(2)o(2) complexes in reversed micelles were compared to that in aqueous system. t ... | 1998 | 12174273 |
| the quantitative measurement of h2o2 generation in isolated mitochondria. | adequate methods to measure the rate of mitochondrial oxygen radical generation are needed since oxygen radicals are involved in many pathologies. a fluorometric method appropriate to measure the rate of generation of h2o2 in intact mitochondria is described. just after isolation of functional mitochondria from fresh tissues, rates of generation of h2o2 are kinetically measured by fluorometry in the presence of homovanillic acid and horseradish peroxidase. the method is specific for h2o2 and is ... | 2002 | 12171072 |
| effect of calcium ion on conformation of horseradish peroxidase isoenzyme c. | horseradish peroxidase isoenzyme c without ligand [apo-hrp(c)] was studied by fluorescence spectroscopy in this paper. it was observed: 1. there was a distinct tyr fluorescence in the intrinsic fluorescence of apo-hrp(c), which was seldom observed in other "b" proteins; 2. low concentration denaturants (<2 mol/l urea or 0.2 mol/l guhcl) could increase the fluorescence intensity of the trp residue; however they did not change the spectrum characteristics; 3. further increase in the denaturant con ... | 1998 | 12168023 |
| peg-modified horseradish peroxidase and its properties in nonaqueous media. | modification of enzymes can enhance their activities in organic solvents. horseradish peroxidase (hrp) was modified with methoxy-peg 5000 which was linked onto hrp peptidal free aminos or onto the aminos introduced through the oxidation of sugar side chains of hrp. it was found the enzyme with peg linked to peptide chain expressed a nearly same activity as the native hrp in aqueous system. however, peg modified hrp by oxidation of carbohydrate chains remained only about one third activity of the ... | 1998 | 12168005 |
| a novel reaction media for horseradish peroxidase (hrp) catalysis in organic solvents. | it is important to select favorable reaction media for use of enzymes in organic synthesis. in the presence of peg with a certain molecular weight, toluene was able to dissolve horseradish peroxidase and the latter maintained a high activity. the hrp reaction conditions, such as ratio of peg/toluene, water content, ph, and substrate concentration were investigated. it was found that the activity of hrp increased when peg concentration was low and water content was high. in such a system, the enz ... | 1998 | 12168003 |
| polysaccharide degradation by fenton reaction--or peroxidase-generated hydroxyl radicals in isolated plant cell walls. | the formation of hydroxyl radicals (oh*) by peroxidase was confirmed by epr spectroscopy using ethanol/alpha-(4-pyridyl-1-oxide)-n-tert-butylnitrone as a spin-trapping system specific of oh*. the effect of oh*, generated either non-enzymatically with the fenton reaction (h(2)o(2) + fe(2+)) or with horseradish peroxidase in the presence of o(2) and nadh, on cell walls isolated from maize (zea mays) coleoptiles or soybean (glycine max) hypocotyls was investigated. oh* produced by these reactions a ... | 2002 | 12165299 |
| generation of reactive oxygen species in the enzymatic reduction of pbcro4 and related dna damage. | free radical reactions are believed to play an important role in the mechanism of cr(vi)-induced carcinogenesis. most studies concerning the role of free radical reactions have been limited to soluble cr(vi). various studies have shown that solubility is an important factor contributing to the carcinogenic potential of cr(vi) compounds. here, we report that reduction of insoluble pbcro4 by glutathione reductase in the presence of nadph as a cofactor generated hydroxyl radicals (.oh) and caused d ... | 2013 | 12162449 |
| the role of p53 and ki67 in paget's disease of the vulva and the breast. | paget's disease of the vulva (pdv) and paget's disease of the breast (pdb) are uncommon diseases, accounting for approximately 1% of all vulval neoplasms and 0.5-4% of all breast cancers, respectively. in 10-30% of vulval cases an invasive adenocarcinoma is present. in such cases the disease is often aggressive and recurrence rate is high. this is in contrast to pdb where the general consensus is that almost all cases are associated with an in situ or invasive ductal carcinoma. our aim was to ex ... | 2002 | 12144821 |
| mechanistic and molecular investigations on stabilization of horseradish peroxidase c. | the enzyme horseradish peroxidase (hrp) shows a decreasing activity when the enzyme's substrate hydrogen peroxide is present with the degree of inactivation being dependent on the incubation time and the hydrogen peroxide concentration. incubation times of some minutes do not inactivate the enzyme independent of the h2o2 concentration. after several hours, only 50% of the activity is found for a medium h2o2 excess, and a >100-fold excess of h2o2 completely inactivates the enzyme. polymeric addit ... | 2002 | 12141662 |
| microfluidic enzyme immunoassay using silicon microchip with immobilized antibodies and chemiluminescence detection. | silicon microchips with immobilized antibodies were used to develop microfluidic enzyme immunoassays using chemiluminescence detection and horseradish peroxidase (hrp) as the enzyme label. polyclonal anti-atrazine antibodies were coupled to the silicon microchip surface with an overall dimension of 13.1 x 3.2 mm, comprising 42 porous flow channels of 235-microm depth and 25-microm width. different immobilization protocols based on covalent or noncovalent modification of the silica surface with 3 ... | 2002 | 12141657 |
| preparation of porous titania sol-gel matrix for immobilization of horseradish peroxidase by a vapor deposition method. | a new and facile vapor deposition method has been developed for the preparation of sol-gel matrix. this method was used to form a titania sol-gel thin film and to immobilize horseradish peroxidase (hrp) on a glassy carbon electrode surface for the production of an amperometric hydrogen peroxide biosensor. this process prevented the cracking of conventional sol-gel-derived glasses. the morphologies of both titania sol-gel and the enzyme membranes were characterized using scanning electron microsc ... | 2002 | 12139071 |
| renewable reagentless hydrogen peroxide sensor based on direct electron transfer of horseradish peroxidase immobilized on colloidal gold-modified electrode. | a novel renewable reagentless hydrogen peroxide (h(2)o(2)) sensor based on the direct electron transfer of horseradish peroxidase (hrp) is proposed. the direct electrochemistry of hrp immobilized on a colloidal gold-modified carbon paste electrode (au-cpe) was investigated using electrochemical methods. the immobilized hrp displayed a pair of redox peaks in 0.1m phosphate buffer (pb), ph 7.0, with a formal potential of -0.346 v. the response showed a surface-controlled electrode process with an ... | 2002 | 12137787 |
| aroma compound analysis of eruca sativa (brassicaceae) spme headspace leaf samples using gc, gc-ms, and olfactometry. | the aroma compounds of rocket salad (eruca sativa) spme headspace samples of fresh leaves were analyzed using gc, gc-ms, and olfactometry. more than 50 constituents of the eruca headspace could be identified to be essential volatiles, responsible for the characteristic intense green; herbal; nutty and almond-like; brassicaceae-like (direction of cabbage, broccoli, and mustard); and horseradish-like aroma of these salad leaves. as aroma impact compounds, especially isothiocyanates, and derivative ... | 2002 | 12137490 |
| novel hydrogen peroxide sensors based on peroxidase-carrying poly[pyrrole-co-[4-(3-pyrrolyl)butanesulfonate]] copolymer films. | amperometric hydrogen peroxide biosensors were fabricated by incorporating horseradish peroxidase (hrp) into poly[pyrrole-co-[4-(3-pyrrolyl)butanesulfonate]] (py-ps) copolymer films deposited on an sno2 electrode surface by electropolymerization. the hrp/py-ps electrodes exhibited an extended dynamic range and a markedly improved operational and storage stability, compared with hrp-incorporated polypyrrole (ppy) electrodes prepared under similar conditions. the linear range was expanded from 10( ... | 2002 | 12137372 |
| selective loss of vagal intramuscular mechanoreceptors in mice mutant for steel factor, the c-kit receptor ligand. | vagal intramuscular arrays are mechanoreceptors that innervate smooth muscle fibers and intramuscular interstitial cells of cajal of the proximal gi tract. c-kit mutant mice that lack intramuscular interstitial cells of cajal also lack intramuscular arrays. mice mutant for steel factor, the ligand for the c-kit receptor, were studied to extend and validate these previous findings and to characterize associated changes in food intake. injections of wheat germ agglutinin-horseradish peroxidase and ... | 2002 | 12136263 |
| peroxidase-mediated transformation of hydroxy-9,10-anthraquinones. | a peroxidase (ec 1.11.1.7) has been isolated and purified from senna angustifolia. the enzyme was purified by ion-exchange chromatography on high q and high s columns. sds-page electrophoresis showed that the protein has a molecular mass of approximately 70 kda. hydroxy-anthraquinones and hydroxy-anthracenones were evaluated as substrate of s. angustifolia and horseradish peroxidases. both peroxidases catalyzed the oxidation of alizarin and purpurin anthraquinones to the corresponding 3,3'-biali ... | 2002 | 12126702 |
| mechanisms of compound i formation in heme peroxidases. | the formation of compound i is the first step in the reaction mechanism of plant heme peroxidases. this intermediate stores two oxidizing equivalents from hydrogen peroxide as an oxyferryl iron center and a radical, either on the porphyrin ring or on a tryptophan residue. site-directed mutagenesis has proved to be a most useful tool for the identification of the intermediates involved and the resulting nature of the compound i formed. although there is no doubt that an acid-base mechanism operat ... | 2002 | 12121759 |
| thermal and conformational stability of seed coat soybean peroxidase. | soybean peroxidase (sbp) obtained from the soybean seed coats belongs to class iii of the plant peroxidase superfamily. detailed circular dichroism and steady state fluorescence studies have been carried out to monitor thermal as well as denaturant-induced unfolding of sbp and apo-sbp. melting of secondary and tertiary structures of sbp occurs with characteristic transition midpoints, t(m), of 86 and 83.5 degrees c, respectively, at neutral ph. removal of heme resulted in greatly decreased therm ... | 2002 | 12119017 |
| brain phagocytes may empty tissue debris into capillaries. | the possibility that brain phagocytes may empty remnants of degenerated neurons into capillaries has been studied in frogs. degeneration of nerve fibers was brought about by transectioning the optic tract, the tectothalamic and tectoisthmic tracts, the postoptic commissure or the radial nerve. to help identification of phagocytozed degenerated neuronal elements, the transected fibers were filled either with horseradish peroxidase (hrp) or cobaltous-lysine complex. the survival times were 3, 4, 7 ... | 2001 | 12118159 |
| raman evidence that the lyoprotectant poly(ethylene glycol) does not restore nativity to the heme active site of horseradish peroxidase suspended in organic solvents. | resonance raman spectroscopy was used to interrogate the heme active site of horseradish peroxidase (hrp) lyophilized in the presence and absence of the lyoprotectant poly(ethylene glycol) (peg; fw 5000; 0-80% w/w) suspended in acetone, chloroform, or acetonitrile. in aqueous solution, fe(3+)hrp is characterized by a five-coordinate high-spin (5-c hs) heme system. the structure of the heme-active site of hrp in all solvents is perturbed by co-lyophilization of hrp with peg. heme active site stru ... | 2015 | 12099832 |
| spectroscopic study on structure of horseradish peroxidase in water and dimethyl sulfoxide mixture. | the structure of horseradish peroxidase (hrp) in phosphate buffered saline (pbs)/dimethyl sulfoxide (dmso) mixed solvents at different compositions is investigated by ir, electronic absorption, and fluorescence spectroscopies. the fluorescence spectra and the amide i spectra of ferric hrp [hrp(fe3+)] show that overall structural changes are relatively small up to 60% dmso. although the amide i band of hrp(fe3+) shows a gradual change in the secondary structure and a decrease in the contents of a ... | 2002 | 12073932 |
| introduction of functional groups onto polypropylene and polyethylene surfaces for immobilization of enzymes. | polypropylene and polyethylene surfaces are activated by introducing an active functional group through 1-fluoro-2 nitro-4-azidobenzene by uv irradiation. horseradish peroxidase and glucose oxidase are immobilized onto the activated surfaces, simply by incubating the enzymes at 37 degrees c. when untreated surfaces are used, insignificant immobilization of the enzymes is observed. | 2002 | 12069416 |
| reactivity toward thiols and cytotoxicity of 3-methylene-2-oxindoles, cytotoxins from indole-3-acetic acids, on activation by peroxidases. | oxidation of indole-3-acetic acid and its derivatives by peroxidases such as that from horseradish produces many products, including 3-methylene-2-oxindoles. these have long been associated with biological activity, but their reactivity has not been characterized. we have previously demonstrated the potential value of substituted indole acetic acids and horseradish peroxidase as the basis for targeted cancer therapy, since the compounds are of low cytotoxicity until oxidized, when high cytotoxic ... | 2002 | 12067256 |
| fused expression of anti-cea single-chain antibody gene with core-streptavidin gene in insect cells. | a fused construct formed by an anti-cea single-chain antibody gene with a core-streptavidin gene(scfv-cs)was inserted into the donor plasmids pfastbachta and expressed in tn-5b1-4 cells. sds-page analysis revealed that the molecular weight expressed product of scfv-cs were 41 kd. using horseradish peroxidase(hrp)labeled biotin as antibody product western blot, one band of 41 kd only was detected. it was also shown by ria that the expression product possessed the ability to bind to its specific a ... | 2000 | 12058186 |
| a fungal auxin antagonist, hypaphorine prevents the indole-3-acetic acid-dependent irreversible inactivation of horseradish peroxidase: inhibition of compound iii-mediated formation of p-670. | hypaphorine, an indolic alkaloid from an ectomycorrhizal fungus is a putative antagonist of indole-3-acetic acid (iaa) known to inhibit the effect of iaa in growing roots of eucalyptus seedling. previously we have used horseradish peroxidase-c (hrp) as a sensitive reporter of iaa-binding to the iaa-binding domain, and reported that hypaphorine specifically inhibits the hrp-catalyzed superoxide generation coupled to oxidation of iaa [kawano et al., biochem. biophys. res. commun. 288]. since bindi ... | 2002 | 12056802 |
| fluorescence in situ hybridization and catalyzed reporter deposition for the identification of marine bacteria. | fluorescence in situ hybridization (fish) with horseradish peroxidase (hrp)-labeled oligonucleotide probes and tyramide signal amplification, also known as catalyzed reporter deposition (card), is currently not generally applicable to heterotrophic bacteria in marine samples. penetration of the hrp molecule into bacterial cells requires permeabilization procedures that cause high and most probably species-selective cell loss. here we present an improved protocol for card-fish of marine planktoni ... | 2002 | 12039771 |
| a method to construct a third-generation horseradish peroxidase biosensor: self-assembling gold nanoparticles to three-dimensional sol-gel network. | a novel method for fabrication of horseradish peroxidase biosensor has been developed by self-assembling gold nanoparticles to a thiol-containing sol-gel network. a cleaned gold electrode was first immersed in a hydrolyzed (3-mercaptopropyl)-trimethoxysilane (mps) sol-gel solution to assemble three-dimensional silica gel, and then gold nanoparticles were chemisorbed onto the thiol groups of the sol-gel network. finally, horseradish peroxidase (hrp) was adsorbed onto the surface of the gold nanop ... | 2002 | 12033329 |
| endogenous biotin staining in a subset of spinal neuronal cell bodies: a potential confounding factor for neuroanatomical studies. | biotinylated compounds are commonly used to label neuronal cell bodies via intracellular filling or retrograde tracing. endogenous concentrations of biotin within a subset of neuronal cell bodies would pose a problem for interpreting such experiments. here i report that a subset of turtle spinal cord neuronal cell bodies strongly stains for biotin, using the avidin-biotin-horseradish peroxidase (abc) reaction, in the absence of any exogenous biotinylated compound. | 2002 | 12031541 |
| electrochemical and peroxidase oxidation study of n'-hydroxyguanidine derivatives as no donors. | the electrochemical properties of a series of n-substituted-n'-hydroxyguanidines were studied. two oxidation potentials of each compound were obtained by cyclic voltammetry. the e(ox1) values were from 0.51 to 0.62v, while the e(ox2) values were from 1.14 to 1.81v in acetonitrile solution. next, their enzymatic controlled no release abilities were evaluated. all n'-hydroxyguanidines exhibited efficient no release abilities under the oxidation by horseradish peroxidase in the presence of h(2)o(2) ... | 2002 | 12031330 |
| the catalytic pathway of horseradish peroxidase at high resolution. | a molecular description of oxygen and peroxide activation in biological systems is difficult, because electrons liberated during x-ray data collection reduce the active centres of redox enzymes catalysing these reactions. here we describe an effective strategy to obtain crystal structures for high-valency redox intermediates and present a three-dimensional movie of the x-ray-driven catalytic reduction of a bound dioxygen species in horseradish peroxidase (hrp). we also describe separate experime ... | 2002 | 12024218 |
| optical and ir absorption as probe of dynamics of heme proteins. | the spectroscopy of horseradish peroxidase with and without the substrate analogue benzohydroxamic acid (bha) was monitored in different solvents as a function of the temperature in the interval from 10 to 300 k. thermal broadening of the q(0,0) optical absorption band arises mainly from interaction of the electronic pi --> pi transition with the heme vibrations. in contrast, the width of the ir absorption band of co bound to heme is controlled by the coupling of the co transition moment to the ... | 2002 | 12012441 |
| development of a chemiluminescent enzyme immunoassay for urinary 1-hydroxypyrene. | a chemiluminescent enzyme-immunoassay for urinary 1-hydroxypyrene has been developed and optimized. the enzymatic activity of horseradish peroxidase-labeled tracer was measured with an enhanced chemiluminescent system and the results were compared with those from conventional colorimetric detection. the method fulfilled all the requirements of accuracy and precision and the detection limit was 0.001 pmol/well, which enabled analysis in less than 1 microl urine. subjects working in the center of ... | 2002 | 12012185 |
| electrochemical studies on reconstituted horseradish peroxidase modified carbon paste electrodes. | horseradish peroxidase (hrp) is a heme protein that acts specifically on h(2)o(2) as the electron acceptor. hemin (ferriprotoporhyrin-ix) is the prosthetic group of the enzyme. a direct molecular wire to the redox center of the enzyme is expected to enhance the electrochemical response of the enzyme. native hrp was immobilized onto the surface of glassy carbon (gc) matrix using a 16-atom spacer arm. we have also immobilized the redox center of the enzyme (hemin) through one of the propionate gro ... | 2002 | 12009454 |
| a glucose/hydrogen peroxide biofuel cell that uses oxidase and peroxidase as catalysts by composite bulk-modified bioelectrodes based on a solid binding matrix. | an improved composite bulk-modified bioelectrode setup based on a solid binding matrix (sbm) has been used to develop a glucose/hydrogen peroxide biofuel cell. fuel is combined through a catalytically promoted reaction with oxygen into and oxidized species and electricity. the present work explores the feasibility of a sugar-feed biofuel cell based on sbm technology. the biofuel cell that utilizes mediators as electron transporters from the glucose oxidation pathway of the enzyme directly to ele ... | 2002 | 12009453 |
| indirect evidence of direct electron communication between the active site of galactose oxidase and a graphite electrode. | bi-enzymatic biosensor based on galactose oxidase (galod) and horseradish peroxidase (hrp) using ferrocene as an efficient mediator was constructed. when a dependence of a working potential on the sensor performance was examined, an unusual behaviour was observed. with increasing of an applied working potential a lower concentration of substrate to attain full linear range was needed. a fully linear dependence from the first substrate addition was observed at and above the working potential of 1 ... | 2002 | 12009437 |
| oxidation of kojic acid catalyzed by manganese peroxidase from ceriporiopsis subvermispora in the absence of hydrogen peroxide. | we have previously reported the oxidation of kojic acid catalyzed by manganese peroxidase (mnp) from ceriporiopsis subvermispora. this reaction is strictly dependent on mn(ii), although it does not require the addition of hydrogen peroxide. we have extended these studies because this reaction can be considered as a model system for the in situ generation of hydrogen peroxide in natural environments. we show here that oxidation of kojic acid with horseradish peroxidase (hrp) plus hydrogen peroxid ... | 2002 | 12008865 |
| effect of dimethyl sulfoxide on the structure and the functional properties of horseradish peroxidase as observed by spectroscopy and cyclic voltammetry. | electrochemical biosensors have found wide application in food and clinical areas, as well as in environmental field. a large number of articles focused on horseradish peroxidase (hrp)-based biosensors have been published in the last decade, due to the capability of hrp to quantitatively detect the presence of hydrogen peroxide produced in a reaction. at present a large body of multi-enzymatic amperometric biosensors are realized by entrapping hrp together with other enzymes into a polymeric mat ... | 2002 | 12007604 |
| indirect detection of photosensitizer ex vivo. | photodynamic therapy induces the production of reactive oxygen species (ros) within tissues exposed to laser light after administration of a sensitizer. in the context of continuing clinical and commercial development of chemicals with sensitizing properties, a minimally invasive assay is needed to determine the tissue kinetics of fluorescent or non-fluorescent photoreactive drugs. the level of ros was determined ex vivo from 1 mm3 biopsy samples using 2'-7' dichlorofluorescin diacetate (dcfh-da ... | 2002 | 12007464 |
| spectroscopic evidence in support of horseradish peroxidase compound ii-catalyzed oxidation of salicylic acid but not of phenylethylamine. | salicylic acid and phenylethylamine are putative substrates for naturally occurring reactions for generation of reactive oxygen species, which are catalyzed by plant peroxidases. here, we used commercially available highly purified horseradish peroxidase-c (hrp-c) as a model enzyme for spectroscopic analysis, and obtained data suggesting that the compound ii form of hrp-c does not utilize phenylethylamine as substrate. in contrast, addition of salicylic acid to compound ii resulted in rapid conv ... | 2002 | 12005064 |
| spectroscopic evidence that salicylic acid converts a temporally inactivated form of horseradish peroxidase (compound iii) to the irreversibly inactivated verdohemoprotein (p-670). | we obtained spectroscopic evidence in support of salicylate-dependent inactivation of horseradish peroxidase-c. addition of salicylate to the enzyme arrested at a temporal inactive state (compound iii) in the presence of h2o2, resulted in rapid and irreversible inactivation of the enzyme yielding verdohemoproteins (p-670). multiple roles for salicylate in peroxidase-catalyzed reactions are discussed. | 2002 | 12005063 |
| [determination of isothiocyanates and related compounds in mustard extract and horseradish extract used as natural food additives]. | amounts of isothiocyanates and related compounds in a mustard extract and a horseradish extract for food additive use were determined by gc, after confirmation of the identity of gc peaks by gc/ms. amounts of allyl isothiocyanate, which included that of allyl thiocyanate, because most of the allyl thiocyanate detected in the sample was assumed to have been formed from allyl isothiocyanate during gc analysis, were 97.6% and 85.4%, in the mustard extract and the horseradish extract, respectively. ... | 2002 | 11998313 |
| incorporation of horseradish peroxidase in a kieselguhr membrane and the application to a mediator-free hydrogen peroxide sensor. | horseradish peroxidase was incorporated in a kieselguhr membrane. the electron-transfer process of the enzyme was examined by cyclic voltammetry. it was observed that the electron-transfer reactivity of horseradish peroxidase was greatly enhanced, and that direct electrochemistry was accordingly feasible. using the merits of the direct electron-transfer reactivity of horseradish peroxidase and its specific enzymatic catalysis towards hydrogen peroxide, an unmediated hydrogen peroxide biosensor w ... | 2001 | 11990539 |
| activity and conformational changes of horseradish peroxidase in trifluoroethanol. | the effect of trifluoroethanol (tfe) on horseradish peroxidase (hrp) was determined using activity assay and spectral analysis including optical absorption, circular dichroism (cd), and intrinsic fluorescence. the enzyme activity increased nearly twofold after incubation with 5-25% (v/v) concentrations of tfe. at these tfe concentrations, the tertiary structure of the protein changed little, while small changes occurred at the active site. further increases in the tfe concentration (25-40%) decr ... | 2002 | 11989716 |
| increase in descending brain-spinal cord projections with age in larval lamprey: implications for spinal cord injury. | the purpose of this study was to determine whether new descending brain-spinal cord projections are added with age in larval lamprey and might contribute substantially to restoration of these projections following spinal cord injury. retrograde horseradish peroxidase (hrp) labeling of descending brain neurons was performed in "young" and "old" larval lamprey that differed in age by at least one year. in old larval lamprey, significantly more descending brain neurons projected to specific rostral ... | 2002 | 11977116 |
| retinofugal projections in the short-tailed opossum (monodelphis domestica). | in the current investigation, retinofugal projections to midbrain and thalamic nuclei of monodelphis domestica were investigated using wheat-germ agglutinin conjugated to horseradish peroxidase (wga-hrp). large intraocular injections of wga-hrp were placed into the eye, and patterns of labeled axon terminals were related to nuclear boundaries in tissue that was stained for nissl or reacted for cytochrome oxidase (co). our results demonstrate that the major projection from the retina is to the co ... | 2002 | 11977115 |
| sol-gel encapsulated horseradish peroxidase: a catalytic material for peroxidation. | this study addresses the viability of sol-gel encapsulated hrp (hrp:sol-gel) as a recyclable solid-state catalytic material. ferric, ferric-cn, ferrous, and ferrous-co forms of hrp:sol-gel were investigated by resonance raman and uv-visible methods. electronic and vibrational spectroscopic changes associated with changes in spin state, oxidation state, and ligation of the heme in hrp:sol-gel were shown to correlate with those of hrp in solution, showing that the heme remains a viable ligand-bind ... | 2002 | 11960453 |
| an iron hydroxide moiety in the 1.35 a resolution structure of hydrogen peroxide derived myoglobin compound ii at ph 5.2. | the biological conversions of o(2) and peroxides to water as well as certain incorporations of oxygen atoms into small organic molecules can be catalyzed by metal ions in different clusters or cofactors. the catalytic cycle of these reactions passes through similar metal-based complexes in which one oxygen- or peroxide-derived oxygen atom is coordinated to an oxidized form of the catalytic metal center. in haem-based peroxidases or oxygenases the ferryl (fe(iv)o) form is important in compound i ... | 2002 | 11935353 |
| golgi apparatus and tgn during endocytosis. | wheat germ agglutinin labelled with horseradish peroxidase (wga) was used for analyses of endosomal compartments and golgi apparatus in hepg(2) hepatoma cells during early and late periods of endocytosis. wga was rapidly transferred into the golgi region. transport of internalised wga into the golgi apparatus could be classified in three stages. a short stage i, characterised by predominance of vesicular endosomes, was followed by stage ii showing new formations of extended endocytic trans golgi ... | 2002 | 11935290 |
| extent of retinal ganglion cell death in the frog litoria moorei after optic nerve regeneration induced by lesions of different sizes. | some amphibian retinal ganglion cells die during optic nerve regeneration. here we have investigated whether ganglion cell death in the frog litoria moorei is associated with the lesion site. for one experimental series, the optic nerve lesion extended for 0.15 mm; in the other, it extended for 1.5 mm. the extent of ganglion cell death was estimated from cresyl violet-stained whole mounts at 24 weeks post lesion. in other animals, individual regenerating axons were visualised in the optic nerve ... | 2002 | 11932943 |
| identification of protein-derived tyrosyl radical in the reaction of cytochrome c and hydrogen peroxide: characterization by esr spin-trapping, hplc and ms. | the reaction of cytochrome c and h(2)o(2) is known to form a protein-centred radical that can be detected with the spin trap 2-methyl-2-nitrosopropane (mnp). to characterize the mnp/tyrosyl adduct structure that had previously been determined incorrectly [barr, gunther, deterding, tomer and mason (1996) j. biol. chem. 271, 15498-15503], we eliminated unreasonable structure models by esr studies with a series of (13)c-labelled tyrosines, and photochemically synthesized an authentic mnp/tyrosyl ad ... | 2002 | 11931655 |
| parabrachio-cortical connections with the lateral hemisphere in the madagascan hedgehog tenrec: prominent projections to layer 1, weak projections from layer 6. | the present study was undertaken to further characterize and subdivide the rhinal cortex (insular and perirhinal areas) in the hedgehog tenrec (echinops telfairi), a placental mammal with a rather low encephalisation index. injections of wheat germ agglutinin-horseradish peroxidase into the dorsolateral pontine tegmentum revealed a prominent layer 1 projection to several rhinal target areas, while the rhinal cortex only stained weakly for the calcitonin gene-related peptide. among the regions re ... | 2002 | 11927376 |
| horseradish peroxidase-catalyzed oligomerization of ferulic acid on a template of a tyrosine-containing tripeptide. | ferulic acid (fa) is an abundantly present phenolic constituent of plant cell walls. kinetically controlled incubation of fa and the tripeptide gly-tyr-gly (gyg) with horseradish peroxidase and h2o2 yielded a range of new cross-linked products. two predominant series of hetero-oligomers of fa linked by dehydrogenation to the peptidyl tyrosine were characterized by electrospray ionization (tandem) mass spectrometry. one series comprises gyg coupled with 4-7 fa moieties linked by dehydrogenation, ... | 2002 | 11925445 |
| rational design of a polymer specific for microcystin-lr using a computational approach. | a computational approach for the design of a molecularly imprinted polymer (mip) specific for cyanobacterial toxin microcystin-lr is presented. by using molecular modeling software, a virtual library of functional monomers was designed and screened against the target toxin, employed as a template. the monomers giving the highest binding energy were selected and used in a simulated annealing (molecular dynamics) process to investigate their interaction with the template. the stoichiometric ratio ... | 2002 | 11924591 |
| horseradish peroxidase catalyzed nitric oxide formation from hydroxyurea. | hydroxyurea represents an approved treatment for sickle cell anemia and a number of cancers. chemiluminescence and electron paramagnetic resonance spectroscopic studies show horseradish peroxidase catalyzes the formation of nitric oxide from hydroxyurea in the presence of hydrogen peroxide. gas chromatographic headspace analysis and infrared spectroscopy also reveal the production of nitrous oxide in this reaction, which provides evidence for nitroxyl, the one-electron reduced form of nitric oxi ... | 2002 | 11916434 |
| formation of a bioconjugate composed of hemin, smectite, and quaternary ammonium chloride that is soluble and active in hydrophobic media. | hemin (fe(3+)) was adsorbed onto synthetic smectite (clay mineral) intercalated with a quaternary alkenylammonium compound, dioleyldimethylammonium chloride (doa), to form a hemin-smectite-doa conjugate. the hemin-smectite-doa conjugate was soluble in organic solvents such as benzene and toluene to form a transparent colloidal solution with a light yellow color. its absorption spectrum in benzene showed two bands, 600 and 568 nm, in the visible region and a sharp soret band at 400 nm with the mo ... | 2013 | 11906251 |
| ontogeny of the follicular dendritic cell phenotype and function in the postnatal murine spleen. | follicular dendritic cells (fdcs) represent a unique cell population of antigen trapping cells restricted to follicles within the secondary lymphoid tissues. fdcs appear to be involved in the formation of primary follicles during the ontogeny of lymphoid tissue. we sought to determine the kinetics and tissue distribution of cells in the spleen of newborn mice expressing various differentiation antigens restricted to fdcs using immunohistochemistry with monoclonal antibodies (mab) against fdcs an ... | 2001 | 11902828 |
| visual cortical organization at the single axon level: a beginning. | single axon analysis of visual cortical connections is an important extension of previous anterograde studies using 3h-amino acids or wheat germ agglutinin-conjugated horseradish peroxidase (wga-hrp). the higher resolution tracers-phaseolus vulgaris-leucoagglutinin (pha-l), biocytin, biotinylated dextran amine (bda) and dextran-conjugates-have already produced new results, simply by providing improved visualization, concerning laminar definition and possible subtypes of connections, as well as t ... | 2002 | 11900825 |
| the regioselectivity of glutathione adduct formation with flavonoid quinone/quinone methides is ph-dependent. | in the present study, the formation of glutathionyl adducts from a series of 3',4'-dihydroxy flavonoid o-quinone/p-quinone methides was investigated with special emphasis on the regioselectivity of the glutathione addition as a function of ph. the flavonoid o-quinones were generated using horseradish peroxidase, and upon purification by hplc, the glutathionyl adducts were identified by lc/ms as well as (1)h and (13)c nmr. the major ph effect observed for the glutathione conjugation of taxifolin ... | 2002 | 11896681 |
| peroxidase-catalyzed oxidative coupling of phenols in the presence of geosorbents: rates of non-extractable product formation. | oxidative coupling processes in subsurface systems comprise a form of natural contaminant attenuation in which hydroxylated aromatic compounds (hacs) are incorporated into soil/sediment organic matter matrices. here we describe the oxidative coupling of phenol catalyzed by horseradish peroxidase (hrp) in systems containing two geosorbents having organic matter of different composition; specifically chelsea soil, a near-surface geologically young soil having a predominantly humic-type soil/sedime ... | 2002 | 11878372 |
| intestinal permeability and bacterial translocation are uncoupled after small bowel resection. | gut barrier failure and bacterial translocation have been proposed to cause infection and sepsis in patients with the short bowel syndrome. this study tested the hypothesis that permeability is increased in the adapting remnant ileum after massive small bowel resection (sbr). | 2002 | 11877654 |
| a nonclassical estrogen membrane receptor triggers rapid differential actions in the endocrine pancreas. | glucose homeostasis in blood is mainly maintained by insulin released from beta-cells and glucagon released from alpha-cells, both integrated within the pancreatic islet of langerhans. the secretory processes in both types of cells are triggered by a rise in intracellular calcium concentration ([ca2+](i)). in this study, rapid effects of the natural hormone e2 on [ca2+](i) were studied in both types of cells within intact islets using laser scanning confocal microscopy. alpha- and beta-cells sho ... | 2002 | 11875108 |
| sol-gel encapsulated enzyme arrays for high-throughput screening of biocatalytic activity. | we developed versatile low-cost arrays of sol-gel-encapsulated enzymes (referred to as solzymes) suitable for repeated assays of bioactivity or enzyme inhibition. sol-gel microstructures containing active enzymes were stabilized on glass at moderate ph and room temperature without harsh calcination. a multi-well bilayer of polydimethylsiloxane was used to support the solzyme array and contain the reaction medium. each of the 147 microwells has a working volume of 5 mul and contains 50 mug of imm ... | 2002 | 11870613 |
| antiperoxidase antibodies enhance refolding of horseradish peroxidase. | the effect of monoclonal antibodies on protein folding was studied using horseradish peroxidase refolding from guanidine hydrochloride as a model process. among the five antiperoxidase clones tested, one was found to increase the yield of catalytically active peroxidase after guanidine treatment. the same clone also increased the activity of the native peroxidase by a factor of 2-2.5. while peroxidase refolding under standard conditions resulted in the recovery of only 7-8% of the initial cataly ... | 2002 | 11866459 |
| chemical deglycosylation can induce methylation, succinimide formation, and isomerization. | interpretation of deglycosylation studies relies heavily on the absence of modifications to the polypeptide chain. we have found that by using a common chemical deglycosylation technique, one can effect at least three changes in a peptide's structure: methylation, isomerization, and ring formation. it was determined that the conditions of chemical deglycosylation introduce a +14 da shift in the masses of our model peptides, rkdvy, rkevy, and horseradish peroxidase. this shift is localized to aci ... | 2001 | 11838545 |
| a peroxidase isoenzyme secreted by turnip (brassica napus) hairy-root cultures: inactivation by hydrogen peroxide and application in diagnostic kits. | we have purified various peroxidase isoenzymes from roots and hairy-root cultures of turnip (brassica napus) which could potentially be used for commercial applications such as an enzyme immunoassays, diagnostic test kits, wastewater treatment and soil remediation. one of them, a basic peroxidase called hr2, was secreted into the medium of turnip hairy-root cultures. hr2 had a pi of 9.6, a molecular mass of 39.3 kda and showed great thermostability. the inactivation of hr2 by h2o2 in the absence ... | 2002 | 11834124 |
| heat shock response reduces intestinal permeability in septic mice: potential role of interleukin-10. | sepsis and other critical illnesses are associated with increased permeability of the intestinal mucosa. loss of mucosal integrity may lead to multiple organ failure in these conditions. we tested the hypothesis that induction of the heat shock response reduces sepsis-induced increase in intestinal permeability. the heat shock response was induced in mice by intraperitoneal injection of 10 mg/kg sodium arsenite. two hours later, at which time mucosal heat shock protein 72 levels were increased, ... | 2002 | 11832385 |
| [a scanning method for detecting colorectal tumors]. | to develop a method for survey of colorectal tumors. | 1999 | 11829931 |