| [oxidation of luminol with peroxidase from royal palm leaves]. | we optimized the conditions for luminol oxidation by hydrogen peroxide in the presence of peroxidase (ec 1.11.1.7) from royal palm leaves (roystonea regia). the ph range (8.3-8.6) corresponding to maximum chemiluminescence was similar for palm tree peroxidase and horseradish peroxidase. variations in the concentration of the tris buffer were accompanied by changes in chemiluminescence. note that maximum chemiluminescence was observed in the 30 mm solution. the detection limit of the enzyme assay ... | 2013 | 17345855 |
| fluorescence in situ hybridization for the identification of environmental microbes. | this chapter presents a protocol for the phylogenetic identification of microorganisms in environmental samples (water and sediments) by means of fluorescence in situ hybridization (fish) with ribosomal rna-targeted oligonucleotide probes and signal amplification (catalyzed reporter deposition [card]). the fish probes are labeled with the enzyme, horseradish peroxidase (hrp). a subsequent deposition of fluorescently labeled tyramides results in substantially higher signal intensities of target c ... | 2007 | 17332640 |
| hypromellose films for the delivery of growth factors for wound healing. | hypromellose was investigated as a carrier for extending topical growth factor delivery to wounds. films of hypromellose (e4m, k4m and e10m) containing a model protein horseradish peroxidase (1% w/w hrp, mw 40 000) were cast from aqueous solutions and dried at 37 degrees c. in-vitro release was determined using franz-type diffusion cells and films were mounted directly into the franz cell or cast onto a wound dressing (melolin) backing. there was an initial burst release then an extended release ... | 2007 | 17331339 |
| peroxidase-mediated removal of a polychlorinated biphenyl using natural organic matter as the sole cosubstrate. | natural organic matter (nom) of hydroxylated aromatic character can undergo catalyst-mediated self-coupling reactions to form larger molecular aggregates. indeed, such reactions are central to natural humification processes. nonhydroxylated persistent aromatic contaminants such as polychlorinated biphenyls (pcbs) are, conversely, inert with respect to such reactions. it is here demonstrated however that significant coincidental coupling and removal of a representative aqueous-phase pcb occurs du ... | 2007 | 17328199 |
| sunlight-induced covalent immobilization of proteins. | horseradish peroxidase (hrp) and glucose oxidase (god) were immobilized by sunlight onto the photoreactive cellulose membrane prepared by the reaction of cellulose membrane with 1-fluoro-2-nitro-4-azidobenzene (fnab). a correlation between sunlight intensity and immobilization was studied. sunlight intensity required for optimum immobilization was found to be 21,625lux beyond which no appreciable increase in immobilization was observed. around 2.5-fold increase in absorbance value was observed w ... | 2007 | 19071471 |
| enzymatic oxidation of tert-butylcatechol in the presence of sulfhydryl compounds: application to the amperometric detection of penicillamine. | the high sensitivity that can be attained using an enzymatic system and mediated by 4-tert-butylcatechol (4-tbc) has been verified by on-line interfacing of a rotating biosensor and continuous flow/stopped-flow/continuous-flow processing. horseradish peroxidase, hrp, [ec 1.11.1.7], immobilized on a rotating disk, in presence of hydrogen peroxide catalyzed the oxidation of 4-tbc, whose back electrochemical reduction was detected on glassy carbon electrode surface at -150mv. thus, when penicillami ... | 2007 | 19071433 |
| enumeration of methanotrophic bacteria in the cover soil of an aged municipal landfill. | the enumeration of methanotrophic bacteria in the cover soil of an aged municipal landfill was carried out using (1) fluorescent in situ hybridization (fish) with horseradish peroxidase-labeled oligonucleotide probes and tyramide signal amplification, also known as catalyzed reporter deposition-fish (card-fish), and (2) most probable number (mpn) method. the number of methanotrophs was determined in cover soil samples collected during april-november 2003 from a point with low ch(4) emission. the ... | 2007 | 17323117 |
| enzyme immunosensing of pepsinogens 1 and 2 by scanning electrochemical microscopy. | scanning electrochemical microscopy (secm) was applied to a dual enzyme immunoassay for the detection of pepsinogen 1 (pg1) and pepsinogen 2 (pg2). sandwich-type immunocomplexes labeled with horseradish peroxidase (hrp) were constructed on microspots consisting of anti-pg1 igg antibody and anti-pg2 igg antibody. these microspots were fabricated on a hydrophobic glass substrate using a capillary microspotting technique. in the presence of h(2)o(2) and ferrocenemethanol (fcoh; used as an electron ... | 2007 | 17321125 |
| fabrication of a miniature cmos-based optical biosensor. | this work presents a novel, miniature optical biosensor by immobilizing horseradish peroxidase (hrp) or the hrp/glucose oxidase (gox) coupled enzyme pair on a cmos photosensing chip with a detection area of 0.5 mm x 0.5 mm. a highly transparent teos/pdms ormosil is used to encapsulate and immobilize enzymes on the surface of the photosensor. interestingly, hrp-catalyzed luminol luminescence can be detected in real time on optical h(2)o(2) and glucose biosensors. the minimum reaction volume of th ... | 2007 | 17320371 |
| electron transfer dissociation of n-glycopeptides: loss of the entire n-glycosylated asparagine side chain. | the recently introduced electron transfer dissociation (etd) technique opens new possibilities for the structural characterization of glycoproteins at the glycopeptide level. in this report, we investigate the etd mass spectra of tryptic n-glycopeptides of the model glycoprotein horseradish peroxidase (hrp). multiply protonated n-glycopeptides obtained by electrospray ionization were subjected to etd. fragment ions obtained by etd were further analyzed by collision-induced dissociation (cid) (ms ... | 2007 | 17311219 |
| arthromyces ramosus peroxidase produces two chlorinating species. | we previously reported that the hemes of horseradish peroxidase (hrp) and arthromyces ramosus peroxidase (arp) undergo vinyl and meso-carbon modifications when the enzymes oxidize chloride ion. here we demonstrate for arp that, although both modifications exhibit the same ph profile with an optimum at approximately ph 4.0, monochlorodimedone suppresses the vinyl but not meso-carbon modifications. furthermore, meso-chlorination occurs when arp reacts with exogenous hocl, implicating an fe(iii)-o- ... | 2007 | 17303078 |
| effect of the luminol signal enhancer selection on the curve parameters of an immunoassay and the chemiluminescence intensity and kinetics. | in the present study, three luminol signal enhancers {4-methoxyphenol, 4-hydroxybiphenyl and 4-(1h-pyrrol-1-yl)phenol} were utilized in the chemiluminescence (cl) substrate solution of horseradish peroxidase (hrp). the latter was applied in a heterogenous enzyme immunoassay that has been previously described. the employment of these molecules greatly affected important assay parameters, such as detection limit and the range of the calibration curve and the results were compared with those obtain ... | 2007 | 19071393 |
| enhancing effect of phenylboronic acid compounds and their interactions with the diol groups of saccharides in a capillary electrophoresis-chemiluminescence detection system. | in our previous study, we proposed molecular recognition of mono- and disaccharides making use of the interaction between their diol groups and p-iodophenylboronic acid in capillary electrophoresis with a chemiluminescence detection system. here, to extend our knowledge of molecular recognition, we first examined the enhancing effects of four phenylboronic acid compounds other than p-iodophenylboronic acid i.e., 4-biphenylboronic acid, 4-octyloxyphenyl-boronic acid, 3-octyloxyphenylboronic acid, ... | 2007 | 17297238 |
| substrate binding and protein conformational dynamics measured by 2d-ir vibrational echo spectroscopy. | enzyme structural dynamics play a pivotal role in substrate binding and biological function, but the influence of substrate binding on enzyme dynamics has not been examined on fast time scales. in this work, picosecond dynamics of horseradish peroxidase (hrp) isoenzyme c in the free form and when ligated to a variety of small organic molecule substrates is studied by using 2d-ir vibrational echo spectroscopy. carbon monoxide bound at the heme active site of hrp serves as a spectroscopic marker t ... | 2007 | 17296942 |
| first enzymatic synthesis of water-soluble conducting poly(3,4-ethylenedioxythiophene). | the enzymatically catalyzed polymerization of 3,4-ethylenedioxythiophene in the presence of polystyrenesulfonate is introduced. this is the first time that an enzymatically catalyzed poly(3,4-ethylenedioxythiophene) (pedot) is reported. horseradish peroxidase enzyme was used as a catalyst for the polymerization process leading to a water-soluble pedot that was characterized by uv-vis spectra, fourier transform infrared, and electrical conductivity measurements. water-soluble pedot showed excelle ... | 2007 | 17291051 |
| hybrid bioelectrocatalyst for hydrogen peroxide reduction: immobilization of enzyme within organic-inorganic film of structured prussian blue and pedot. | fabrication of structured film (on glassy carbon substrate) composed of compact prussian blue (that has been prepared by alternate immersions and through assembling within ultra-thin layers of 4(pyrrole-1-yl)-benzoic acid, ppyba) and poly(3,4-ethylendioxythiophene), pedot, is described. this functionalized film has been characterized by fast charge propagation, and it has served as a redox conducting template for permanent attachment of a model enzyme, horseradish peroxidase, hrp. the resulting ... | 2007 | 17289445 |
| estimation of the membrane permeability of liposomes via use of eosin y chemiluminescence catalysed by peroxidase encapsulated in liposomes. | the initial rate of horseradish peroxidase (hrp)-catalysed chemiluminescence (cl) reaction in an aqueous compartment of liposomes was applied to the estimation of membrane permeability of liposomes. hrp-encapsulated liposomes were prepared by an extrusion method, and a cl reagent and h(2)o(2) were added into the liposomes suspensions. fluorescein, eosin y and phloxin b, which are xanthene dyes with different chemical structures, were used as cl reagents. xanthene dye and h(2)o(2) permeate into t ... | 2013 | 17285565 |
| kinetic characterization of the oxidation of esculetin by polyphenol oxidase and peroxidase. | esculetin has been described as an inhibitor of tyrosinase and polyphenol oxidase and, therefore, of melanogenesis. in this work, we demonstrate that esculetin is not an inhibitor but a substrate of mushroom polyphenol oxidase (ppo) and horseradish peroxidase (pod), enzymes which oxidize esculetin, generating its o-quinone. since o-quinones are very unstable, the usual way of determining the enzymatic activity (slope of recordings) is difficult. for this reason, we developed a chronometric metho ... | 2007 | 17284853 |
| immobilized horseradish peroxidase as a reusable catalyst for emulsion polymerization. | the study on the adsorption of horseradish peroxidase (hrp) onto silicon wafers was carried out by means of in situ ellipsometry, atomic force microscopy (afm) and contact angle measurements. a smooth hrp layer adsorbed onto si wafers. the enzymatic activity of free or adsorbed hrp was determined by the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (abts) and by the emulsion polymerization of ethylene glycol dimethacrylate (egdma). upon adsorbing, hrp molecules might have u ... | 2007 | 17279684 |
| synthesis and characterization of both ionically and enzymatically cross-linkable alginate. | alginate with phenol moieties in the polymer side chains was synthesized through the conjugation reaction of alginate and tyramine. immersing an aqueous solution of the alginate containing horseradish peroxidase into a solution containing h(2)o(2) caused the solution to gel via peroxidase-catalyzed oxidative coupling of the phenols. in addition, alginate prepared under appropriate reaction conditions retained the attractive properties associated with unmodified alginate; spherical gel beads were ... | 2007 | 17275429 |
| kinetic characterization of the oxidation of chlorogenic acid by polyphenol oxidase and peroxidase. characteristics of the o-quinone. | chlorogenic acid is the major diphenol of many fruits, where it is oxidized enzymatically by polyphenol oxidase (ppo) or peroxidase (pod) to its o-quinone. in spectrophotometric studies of chlorogenic acid oxidation with a periodate ratio of [cga]0/[io4-]0 < 1 and [cga]0/[io4-]0 > 1, the o-quinone was characterized as follows: lambda(max) at 400 nm and epsilon = 2000 and 2200 m-1 cm-1 at ph 4.5 and 7.0, respectively. in studies of o-quinone generated by the oxidation of chlorogenic acid using a ... | 2007 | 17263494 |
| chemical introduction of disulfide groups on glycoproteins: a direct protein anchoring scenario. | the present work reports a direct glycoprotein immobilization protocol where the protein is chemically modified with disulfide groups which act as anchor molecules able to chemisorb spontaneously onto clean gold surfaces. the specificity of the chemical reaction, for disulfide introduction, toward carbohydrate moieties prevents any cross-reaction with other functional groups present in the protein structure. horseradish peroxidase (hrp) was chosen as a model glycoprotein, and a biologically acti ... | 2007 | 17261022 |
| carbon nanotube/polysulfone composite screen-printed electrochemical enzyme biosensors. | the fabrication, evaluation and attractive performance of multiwall carbon nanotube(mwcnt)/polysulfone biocomposite membrane modified thick-film screen-printed electrochemical biosensors are reported. the fabricated carbon nanotube/polysulfone (cnt/ps) strips combine the attractive advantages of carbon nanotube materials, polysulfone matrix and disposable screen-printed electrodes. such thick-film carbon nanotubes/polysulfone sensors have a well defined performance, are mechanically stable, and ... | 2007 | 17260074 |
| radical energies and the regiochemistry of addition to heme groups. methylperoxy and nitrite radical additions to the heme of horseradish peroxidase. | the heme of hemoproteins, as exemplified by horseradish peroxidase (hrp), can undergo additions at the meso carbons and/or vinyl groups of the electrophilic or radical species generated in the catalytic oxidation of halides, pseudohalides, carboxylic acids, aryl and alkyl hydrazines, and other substrates. the determinants of the regiospecificity of these reactions, however, are unclear. we report here modification of the heme of hrp by autocatalytically generated, low-energy no2* and ch3oo* radi ... | 2007 | 17249668 |
| identification of n-linked glycosylation sites using glycoprotein digestion with pronase prior to maldi tandem time-of-flight mass spectrometry. | glycopeptides are typically prepared by cleaving the proteins with specific proteolytic enzymes, such as trypsin. the resulting glycopeptides tend to have weak mass spectrometry ion signals (esi or maldi) due to their relatively large molecular weight. the identification of glycosylation sites with tandem mass spectrometry is further complicated by fragmentation of both the peptide backbone and the glycan moiety. we explored a method using a nonspecific enzyme, pronase, to generate small glycope ... | 2007 | 17243769 |
| comparison of protein surface attachment on untreated and plasma immersion ion implantation treated polystyrene: protein islands and carpet. | surface attachment of the enzyme horseradish peroxidase (hrp) was studied on untreated and ion beam implanted polystyrene (ps) films. the ps films of 100 nm thickness on a silicon wafer were treated using the plasma immersion ion implantation (piii) technique, with argon ions of energy 20 kev and fluences of up to 2 x 10(16) ions/cm2. differential transmittance fourier transform infrared (ftir) spectra confirmed the presence of proteins on the ps surfaces by detection of the amide a, i, and ii p ... | 2007 | 17243737 |
| a mediator-free amperometric hydrogen peroxide biosensor based on hrp immobilized on a nano-au/poly 2,6-pyridinediamine-coated electrode. | a mediator-free amperometric hydrogen peroxide biosensor was prepared by immobilizing horseradish peroxidase (hrp) enzyme on colloidal au modified platinum (pt) wire electrode, which was modified by poly 2,6-pyridinediamine (ppa). the modified process was characterized by electrochemical impedance spectroscopy (eis), and the electrochemical characteristics of the biosensor were studied by cyclic voltammetry, linear sweep voltammetry and chronoamperometry. the biosensor displayed an excellent ele ... | 2007 | 17242931 |
| spectrophotometric assay for horseradish peroxidase activity based on pyrocatechol-aniline coupling hydrogen donor. | the hydrogen donor couples pyrocatechol-aniline and phenol-aminoantipyrine in the presence of hydrogen peroxide were compared as chromogens for horseradish peroxidase (hrp) assay. uv-visible spectroscopy and high-performance liquid chromatography analysis indicated that during the hrp biocatalytic process, pyrocatechol-aniline was converted to a pink-colored reagent with a lambda(max) of 510 nm, which was used in the assay of hrp activity. electrochemical studies revealed adequate electron trans ... | 2007 | 17234148 |
| heat shock stress ameliorates cytokine mixture-induced permeability by downregulating the nitric oxide and signal transducer and activator of transcription pathways in caco-2 cells. | proinflammatory cytokines are known to impair intestinal barrier function and to activate signaling pathways, whereas heat shock responses prevent cytokine-induced mucosal damage. we hypothesized that heat shock response blocks the effects of proinflammatory cytokines by regulating nitric oxide (no) production and the activities of the janus kinase/signal transducer and activator of transcription (stat) pathway. a monolayer of caco-2 cells were pretreated with sodium arsenite (sa, 500 micromol/l ... | 2007 | 17224793 |
| silk microspheres for encapsulation and controlled release. | a method was developed to prepare silk fibroin microspheres using lipid vesicles as templates to efficiently load protein drugs in active form for controlled release. the lipid was subsequently removed by methanol or sodium chloride treatments, resulting in silk microspheres consisting of beta-sheet structure and about 2 mum in diameter. nacl treated microspheres had smoother surfaces compared to the methanol treatments based on sem analysis, and both types of microspheres had a mixture of multi ... | 2007 | 17218036 |
| direct electron transfer kinetics in horseradish peroxidase electrocatalysis. | the study of direct electron transfer between enzymes and electrodes is frequently hampered by the small fraction of adsorbed proteins that remains electrochemically active. here, we outline a strategy to overcome this limitation, which is based on a hierarchical analysis of steady-state electrocatalytic currents and the adoption of the "binary activity" hypothesis. the procedure is illustrated by studying the electrocatalytic response of horseradish peroxidase (hrp) adsorbed on graphite electro ... | 2007 | 17214499 |
| carbon felt-based bioelectrocatalytic flow detectors: highly sensitive amperometric determination of hydrogen peroxide using adsorbed peroxidase and thionine. | horseradish peroxidase (hrp) and thionine (tn) were co-adsorbed onto a porous carbon felt (cf), and the resulting hrp and tn-adsorbed cf (hrp-tn-cf) was successfully used as a working electrode unit of a novel bioelectrocatalytic flow detector for a highly sensitive amperometric determination of hydrogen peroxide (h(2)o(2)). co-adsorbed tn was essential to enhance the cathodic peak current of h(2)o(2), and the current responses of the hrp-tn-cf-based detector were much larger than those of the h ... | 2007 | 17213627 |
| a novel and simple biomolecules immobilization method: electro-deposition zro2 doped with hrp for fabrication of hydrogen peroxide biosensor. | for the first time, a very novel and simple immobilization method for fabrication of hydrogen peroxide biosensor was reported in this paper. the biocompatible composite hrp-zro(2) thin films were synthesized on gold electrode surface based on electro-deposition zirconia doped with horseradish peroxidase (hrp) by cyclic voltammetry scanning in kcl solution containing zro(2) and hrp. the fabricated process of biosensor was characterized by electrochemical impedance spectroscopy (eis) and the surfa ... | 2007 | 17210197 |
| evaluation of six presumptive tests for blood, their specificity, sensitivity, and effect on high molecular-weight dna. | luminol, leuchomalachite green, phenolphthalein, hemastix, hemident, and bluestar are all used as presumptive tests for blood. in this study, the tests were subjected to dilute blood (from 1:10,000 to 1:10,000,000), many common household substance, and chemicals. samples were tested for dna to determine whether the presumptive tests damaged or destroyed dna. the dna loci tested were d2s1338 and d19s433. leuchomalachite green had a sensitivity of 1:10,000, while the remaining tests were able to d ... | 2007 | 17209919 |
| diazonium-functionalized horseradish peroxidase immobilized via addressable electrodeposition: direct electron transfer and electrochemical detection. | a simple one-step procedure is introduced for the preparation of diazonium-enzyme adducts. the direct electrically addressable deposition of diazonium-modified enzymes is examined for electrochemical sensor applications. the deposition of diazonium-horseradish peroxidase leads to the direct electron transfer between the enzyme and electrode exhibiting a heterogeneous rate constant, ks, of 10.3 +/- 0.7 s-1 and a deltaep of 8 mv (v = 150 mv/s). the large ks and low deltaep are attributed to the in ... | 2007 | 17209577 |
| [sulfate reduction and methanogenesis in the shira and shunet meromictic lakes (khakass republic, russia)]. | the biogeochemical and molecular biological study of the chemocline and sediments of saline meromictic lakes shira and shunet (khakass republic, russia) was performed. a marked increase in the rates of sulfate reduction and methanogenesis was revealed at the medium depths of the chemocline. the rates of these processes in the bottom sediments decreased with depth. the numbers of bacteria, archaea, and of sulfate-reducing bacteria (srb) were determined by fluorescence in situ hybridization with r ... | 2013 | 17205809 |
| nickel-intensified abc-hrp antibody staining of imaginal discs in drosophila. | introductionthis protocol describes a sensitive method for labeling drosophila imaginal disc tissues with a single antiserum. labeling is visualized using a nickel-intensified avidin/biotinylated enzyme complex-horseradish peroxidase (abc-hrp) staining procedure. this method is more sensitive, and has a lower signal-to-noise ratio, than fluorescent labeling. although these methods are useful for visualizing genetic mosaic clones in wandering larval stage imaginal discs and pupal tissues from dro ... | 2007 | 21356991 |
| photophysics and photochemistry of horseradish peroxidase a2 upon ultraviolet illumination. | detailed analysis of the effects of ultraviolet (uv) and blue light illumination of horseradish peroxidase a2, a heme-containing enzyme that reduces h(2)o(2) to oxidize organic and inorganic compounds, is presented. the effects of increasing illumination time on the protein's enzymatic activity, reinheitzahl value, fluorescence emission, fluorescence lifetime distribution, fluorescence mean lifetime, and heme absorption are reported. uv illumination leads to an exponential decay of the enzyme ac ... | 2007 | 17189303 |
| peroxidase activity can dictate the in vitro lignin dehydrogenative polymer structure. | the objective of this study was to assess the influence of the peroxidase/coniferyl alcohol (ca) ratio on the dehydrogenation polymer (dhp) synthesis. the soluble and unsoluble fractions of horseradish peroxidase (hrp)-catalyzed ca dehydrogenation mixtures were recovered in various proportions, depending on the polymerization mode (zutropf zt/zulauf zl) and hrp/ca ratio (1.6-1100purpurogallin u mmol(-1)). the zl mode yielded 0-57%/initial ca of unsoluble condensed dhps (thioacidolysis yields <20 ... | 2007 | 17187834 |
| absorption detection of enzymatic reaction using optical microfluidics based intermittent flow microreactor system. | the advantages of integrating microfluidics into photonics-based biosensing for fabricating microreactor type lab-on-a-chip devices carries a lot of advantages, such as smaller sample volume handling, controlled drug delivery and high throughput diagnosis, which is useful for in situ medical diagnosis and point-of-care (poc) testing. a hybrid integrated optical microfluidic system has been developed for the study of single molecules and enzymatic reactions. the method of optical absorption has b ... | 2006 | 17187445 |
| development of amperometric horseradish peroxidase based biosensors for clozapine and for the screening of thiol compounds. | two amperometric biosensors with immobilized horseradish peroxidase (hrp) were developed for the investigation of the clozapine drug oxidation and for thiols screening based on biosensor signal inhibition. the hrp was retained either in magnetized nanoporous silica microparticles (mmps) or in a carbon paste (cp). the latter served for the carbon paste electrode while the mmps were attracted in close proximity of a magnetized carbon electrode. the potential use of these configurations for drug ox ... | 2007 | 17175155 |
| a coulometric biosensor to determine hydrogen peroxide using a monomolecular layer of horseradish peroxidase immobilized on a glass surface. | a biosensor to detect hydrogen peroxide, by coulometry, down to submicromolar concentration using a monomolecular layer of horseradish peroxidase was developed. in this device 0.3 pmol of the enzyme were covalently immobilized on the glass surface of the biosensor and the enzyme layer was characterized by atomic force microscopy and activity measurements. the glass surface bearing the peroxidase was faced to a carbon electrode in a cell of 1 microl of active volume. the polarization of the worki ... | 2007 | 17174086 |
| picomolar peroxide detection using a chemically activated redox mediator and square wave voltammetry. | a method for low-level, low-potential electrochemical detection of hydrogen peroxide using a chemically activated redox mediator is presented. this method is unique in that it utilizes a mediator, amplex red, which is only redox-active when chemically oxidized by h2o2 in the presence of the enzyme horseradish peroxidase (hrp). when employed in concert with microelectrode square wave voltammetry to optimize sensing at ultralow concentrations (<1 microm), this method exhibits marked improvements i ... | 2006 | 17165848 |
| mast cell-specific gangliosides and fcepsilonri follow the same endocytic pathway from lipid rafts in rbl-2h3 cells. | recent studies have shown that, in mast cells, membrane microdomains rich in cholesterol and glycosphingolipids called lipid rafts play an important role in fcepsilonri signaling. the present study demonstrates that, in rbl-2h3 cells following stimulation, the mast cell-specific gangliosides associated with fcepsilonri are internalized from lipid rafts along with the receptor. when the cells are labeled with iodinated antibodies against the gangliosides or against fcepsilonri and the cell compon ... | 2007 | 17164410 |
| a simple and reliable assay for detecting specific nucleotide sequences in plants using optical thin-film biosensor chips. | here we report the adaptation and optimization of an efficient, accurate and inexpensive assay that employs custom-designed silicon-based optical thin-film biosensor chips to detect unique transgenes in genetically modified (gm) crops and snp markers in model plant genomes. briefly, aldehyde-attached sequence-specific single-stranded oligonucleotide probes are arrayed and covalently attached to a hydrazine-derivatized biosensor chip surface. unique dna sequences (or genes) are detected by hybrid ... | 2007 | 17156412 |
| using novel polysaccharide-silica hybrid material to construct an amperometric biosensor for hydrogen peroxide. | a new type of sol-gel organic-inorganic hybrid material was developed and used for the fabrication of an amperometric hydrogen peroxide biosensor. this material was prepared from natural chitosan and recently introduced completely water-soluble precursor, tetrakis(2-hydroxyethyl) orthosilicates (theos), by the sol-gel process without the addition of organic solvents and catalysts. the gelation time for the sol-gel transition and dynamic rheological properties of the resultant gel matrix could be ... | 2006 | 17149906 |
| investigation of several parameters influencing signal generation in flow-through membrane-based enzyme immunoassay. | rapid-response analytical tests that can be performed at the point of sampling are based on a visual detection system. the influence of different factors on the signal generation in a membrane-based enzyme immunoassay was investigated. the research was applied to a flow-through immunoassay for the detection of ochratoxin a (ota). this assay format is a very convenient, simple and fast qualitative screening tool. conjugates of ota with horseradish peroxidase (hrp) and alkaline phosphatase (ap) we ... | 2007 | 17146620 |
| lmmunoelectron microscopic examination of cord blood cd5+ b cells. | in this study, we have categorized cord blood cd5(+) b cells, which were examined using the horseradish peroxidase-colloidal gold double labeling immunoelectron microscopy, into three subtypes based on their morphology and immunohistochemical characteristics. type 1a cells and type 1b cells (9% and 17% of the cd5(+) b cells, respectively) had few cytoplasmic organelles, a high nuclear/cytoplasmic (n/c) ratio (0.66 +/- 0.03 and 0.58 +/- 0.04, respectively), and a low nuclear contour index (nci) v ... | 2006 | 17142958 |
| treatment of phenolic wastewater by horseradish peroxidase immobilized by bioaffinity layering. | horseradish peroxidase was immobilized by bioaffinity layering and used for the treatment of wastewater containing p-chlorophenol. for this purpose, lectin concanavalin a was bound to sephadex beads. the glycoenzyme peroxidase was layered upon this con a layer. subsequently, alternate layers of the enzyme and con a were applied. the most efficient design consisted of three layers of con a and peroxidase each. this immobilized enzyme preparation retained 80% of the activity of the free peroxidase ... | 2007 | 17140630 |
| disposable biosensor based on enzyme immobilized on au-chitosan-modified indium tin oxide electrode with flow injection amperometric analysis. | indium tin oxide (ito) electrode is used to fabricate a novel disposable biosensor combined with flow injection analysis for the rapid determination of h2o2. the biosensor is prepared by entrapping horseradish peroxidase (hrp) enzyme in colloidal gold nanoparticle-modified chitosan membrane (au-chitosan) to modify the ito electrode. the biosensor is characterized by scanning electron microscope, atomic force microscope, and electrochemical methods. parameters affecting the performance of the bio ... | 2007 | 17134672 |
| cyclic voltammetric responses of horseradish peroxidase multilayers on electrodes. | the catalytic responses obtained with step-by-step neutravidin-biotin deposition of successive monolayers of hrp are analyzed by means of cyclic voltammetry. the theoretical tools that have been developed allowed full characterization of the multilayered hrp coatings by means of a combination between closed-form analysis of limiting behaviors and finite difference numerical computations. an analysis of the experiments in which the number of monolayers was extended to 16 allowed an approximate de ... | 2006 | 17129064 |
| probing traces of hydrogen peroxide by use of a biosensor based on mediator-free dna and horseradish peroxidase immobilized on silver nanoparticles. | a new electrochemical biosensor for determination of hydrogen peroxide (h(2)o(2)) has been developed by immobilizing horseradish peroxidase (hrp) on silver colloids (nanosilver) and use of a dna-functionalized interface. in the presence of the dna and the nanosilver the immobilized hrp gives a pair of well-defined redox peaks with an electron-transfer rate constant of 3.27 +/- 0.91 s(-1) in ph 7.0 pbs. the presence of dna also provides a biocompatible microenvironment for enzyme molecules, great ... | 2007 | 17123066 |
| structural stabilization and functional improvement of horseradish peroxidase upon modification of accessible lysines: experiments and simulation. | horseradish peroxidase (hrp) is an important heme enzyme with enormous medical diagnostic, biosensing, and biotechnological applications. thus, any improvement in the applicability and stability of the enzyme is potentially interesting. we previously reported that covalent attachment of an electron relay (anthraquinone 2-carboxylic acid) to the surface-exposed lys residues successfully improves electron transfer properties of hrp. here we investigated structural and functional consequences of th ... | 2007 | 17114227 |
| inhibition of horseradish peroxidase catalytic activity by new 3-phenylcoumarin derivatives: synthesis and structure-activity relationships. | twenty hydroxylated and acetoxylated 3-phenylcoumarins were synthesized, and the structure-activity relationships were investigated by evaluating the ability of these compounds to modulate horseradish peroxidase (hrp) catalytic activity and comparing the results to four flavonoids (quercetin, myricetin, kaempferol and galangin), previously reported as hrp inhibitors. it was observed that 3-phenylcoumarins bearing a catechol group were as active as quercetin and myricetin, which also show this su ... | 2007 | 17112729 |
| specificity of a dna-based (dnazyme) peroxidative biocatalyst. | a complex formation between hemin and a congruous oligonucleotide not only greatly enhances the former's peroxidative activity but also results in a biocatalyst (dnazyme) with a novel specificity. herein substrate, regio-, enantiomeric, and diastereomeric selectivities of heme, the dnazyme, and the enzyme horseradish peroxidase are comparatively examined. | 2007 | 17091371 |
| dna-directed assembly of polyanilines: modified cytosine nucleotides transfer sequence programmability to a conjoined polymer. | a series of polyaniline (pani) oligomers was constructed from monomer units covalently linked to duplex dna through n-(2-aminoethyl) groups bonded through cytosines. dna oligomers containing the aniline monomers were treated with horseradish peroxidase (hrp) and h2o2 under conditions known to cause polymerization of aniline. no change in the absorption spectrum of the dna was observed for samples containing fewer than four contiguous aniline groups. however, for oligomers containing four, five, ... | 2006 | 17090004 |
| inhibitory and enhancing effects of piroxicam on whole blood chemiluminescence. | the effects of piroxicam on the production of reactive oxygen species by stimulated phagocytes was studied in whole blood by a chemiluminescence (cl) technique in relation to maximum activity, localization and kinetics of radical generation. we found that piroxicam dose-dependently inhibited total (intra- and extracellular) zymosan-stimulated luminol cl (lcl) at a high stimulant concentration (p = 0.0001). piroxicam additionally decreased cytochalasin b-reduced lcl, which shows that the effect o ... | 2013 | 17089362 |
| amperometric hydrogen peroxide biosensor based on the immobilization of hrp on nano-au/thi/poly (p-aminobenzene sulfonic acid)-modified glassy carbon electrode. | a novel hydrogen peroxide biosensor was fabricated for the determination of h(2)o(2). the precursor film was first electropolymerized on the glassy carbon electrode with p-aminobenzene sulfonic acid (p-absa) by cyclic voltammetry (cv). then thionine (thi) was adsorbed to the film to form a composite membrane, which yielded an interface containing amine groups to assemble gold nanoparticles (nano-au) layer for immobilization of horseradish peroxidase (hrp). the electrochemical characteristics of ... | 2007 | 17081615 |
| purification and thermal characterization of a novel peroxidase from a local chick pea cultivar. | a novel peroxidase isolated from a local chick pea (cicer arietinum l.) cultivar (balksar 2000) was purified by means of ammonium sulfate precipitation, deae-cellulose chromatography and two runs on gel filtration. the purified enzyme has a specific activity of 2045 u/mg with 17 % activity recovery. the molecular mass of the enzyme was estimated to be 39 kda by sds-polyacrylamide gel electrophoresis. optimum ph and temperature of the enzyme were 5.5 and 45 degrees c respectively. the thermal den ... | 2006 | 17073725 |
| elementary steps of enzymatic oxidation of nifedipine catalyzed by horseradish peroxidase. | the elementary steps of the enzymatic oxidation of nifedipine (nf) catalyzed by horseradish peroxidase (hrp) have been described based on analysis of kinetic magnetic field effects (mfes). it has been shown that the first step of the catalytic cycle is single electron transfer resulting in formation of nf*(+) radical cation and ferroperoxidase (per(2+)). as a result, comparison with an earlier studied oxidation reaction of nadh catalyzed by hrp evidenced that the enzymatic oxidations of two subs ... | 2006 | 17048950 |
| can the replacement of a single atom in the enzyme horseradish peroxidase convert it into a monoxygenase? a density functional study. | density functional calculations on horseradish peroxidase mutants are presented, whereby one or two of the nitrogen atoms of the axial histidine ligand have been replaced by phosphorus atoms. our calculations show that phosphorus entices a push effect on the oxoiron group, whereas a histidine side chain withdraws electrons. as a result, we predict that a phosphorus-substituted histidine ligand will convert the active form of a peroxidase into a monoxygenase. this subsitution may be useful for th ... | 2006 | 17048883 |
| design and development of a highly stable hydrogen peroxide biosensor on screen printed carbon electrode based on horseradish peroxidase bound with gold nanoparticles in the matrix of chitosan. | the design and development of a screen printed carbon electrode (spce) on a polyvinyl chloride substrate as a disposable sensor is described. six configurations were designed on silk screen frames. the spces were printed with four inks: silver ink as the conducting track, carbon ink as the working and counter electrodes, silver/silver chloride ink as the reference electrode and insulating ink as the insulator layer. selection of the best configuration was done by comparing slopes from the calibr ... | 2007 | 17046233 |
| an efficient proton-coupled electron-transfer process during oxidation of ferulic acid by horseradish peroxidase: coming full cycle. | quantum mechanics/molecular mechanics calculations were utilized to study the process of oxidation of a native substrate (ferulic acid) by the active species of horseradish peroxidase (dunford, h. b. heme peroxidases; wiley-vch: new york, 1999), compound i and compound ii, and the manner by which the enzyme returns to its resting state. the results match experimental findings and reveal additional novel features. the calculations demonstrate that both oxidation processes are initiated by a proto ... | 2006 | 17044722 |
| embryonic development of pleuropodia of the cicada, magicicada cassini. | in many insects the first abdominal segment possesses embryonic appendages called pleuropodia. here we show the embryogenesis of pleuropodial cells of the periodical cicada, magicicada cassini (fisher 1851) (insecta, homoptera, cicadidae). an antibody, anti-horseradish perioxidase (hrp), that is usually neuron-specific strongly marked the pleuropodial anlagen and revealed their ectodermal origin shortly after limb bud formation. thereafter the cells sank into the epidermis and their apical parts ... | 2006 | 19537987 |
| rapid and efficient enzyme encapsulation in a dendrimer silica nanocomposite. | we report the entrapment of horseradish peroxidase and quantitative encapsulation of glucose oxidase within silica nanoparticles by utilizing an amine-terminated dendritic template. our improved strategy employs a water-soluble biomimetic template which is able to catalyze the condensation of si(oh)(4) to silica nanoparticles while trapping an enzyme inside the mesoporous material. kinetic analysis shows enzyme functionality to be mostly unchanged. also, the role of pi and ionic strength within ... | 2006 | 17039576 |
| a europium(iii) complex as an efficient singlet oxygen luminescence probe. | a new europium(iii) complex, [4'-(10-methyl-9-anthryl)-2,2':6',2"-terpyridine-6,6"-diyl]bis(methylenenitrilo) tetrakis(acetate)-eu(3+), was designed and synthesized as a highly sensitive and selective time-gated luminescence probe for singlet oxygen ((1)o2). the new probe is highly water soluble with a large stability constant of approximately 10(21) and a wide ph available range (ph 3-10), and can specifically react with (1)o2 to form its endoperoxide (ep-mtta-eu(3+)) with a high reaction rate ... | 2006 | 17031957 |
| stacked films immobilization of mbth in nafion/sol-gel silicate and horseradish peroxidase in chitosan for the determination of phenolic compounds. | the stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (mbth) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (hrp) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. the stacked films were deposited onto a microscope glass slide by a spin-coating technique. the quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with mbth to form azo-dye produ ... | 2006 | 17031625 |
| electrochemical studies on horseradish peroxidase covalently coupled with redox dyes. | the present study aims at investigating the use of redox dyes as non-diffusional electron mediators in hydrogen peroxide biosensors using horseradish peroxidase (hrp). we observe that the two redox dyes safranine o and neutral red covalently bound to hrp, efficiently mediate electron transfer from the active site of the enzyme to the electrode surface. dyes bound to the enzyme using a spacer arm diaminohexane further enhance the electron transfer. the enzyme electrodes show a linear response to ... | 2007 | 17029778 |
| magnetic field perturbations as a tool for controlling enzyme-regulated and oscillatory biochemical reactions. | the feasibility of magnetic field perturbations as a tool for controlling enzyme-regulated and oscillatory biochemical reactions is studied. our approach is based on recent experimental results that revealed magnetic field effects on the in vitro activity of enzyme systems in accordance with the radical pair mechanism. a minimum model consisting of two coupled enzyme-regulated reactions is discussed that combines, in a self-consistent manner, magnetic field-sensitive enzyme kinetics with non-lin ... | 1998 | 17029747 |
| computer simulation of damped oscillations during peroxidase-catalyzed oxidation of indole-3-acetic acid. | oscillation patterns in horseradish peroxidase (hrp)-catalyzed oxidation of indole-3-acetic acid (iaa) at neutral ph were studied using computer simulation. under certain conditions, such as the presence of a reaction promoter and continuous intake of oxygen from the gaseous phase, the simulated system exhibits damped oscillations of the concentrations of oxygen in the aqueous phase, [o(2)](aq), and of all the reaction intermediates. the critical concentration of oxygen in aqueous phase, [o(2)]( ... | 1998 | 17029712 |
| oscillations in peroxidase-catalyzed reactions and their potential function in vivo. | the peroxidase-oxidase reaction has become a model system for the study of oscillations and complex dynamics in biochemical systems. in the present paper we give an overview of previous experimental and theoretical studies of the peroxidase-oxidase reaction. recent in vitro experiments have raised the question whether the reaction also exhibits oscillations and complex dynamics in vivo. to investigate this possibility further we have undertaken new experimental studies of the reaction, using hor ... | 1998 | 17029705 |
| identification of immunoglobulins that recognize 3-nitrotyrosine in patients with acute lung injury after major trauma. | tyrosine nitration is a nitric oxide-derived post-translational modification of proteins. elevated levels of specific plasma proteins modified by tyrosine nitration have been detected during acute and chronic inflammatory conditions, including acute lung injury (ali). in the present study we examined whether circulating immunoglobulins against nitrated proteins are present in the plasma of subjects with clinically documented ali. affinity chromatography using covalently linked 3-nitrotyrosine wa ... | 2007 | 17023686 |
| optical biochemical sensor for determining hydroperoxides in nonpolar organic liquids as archetype for sensors consisting of amphiphilic conetworks as immobilisation matrices. | this paper reports the successful design of a prototype of an optical biochemical sensor for the determination of hydroperoxides in nonpolar organic liquids. the sensor consists of a matrix of an amphiphilic polymer conetwork (apcn), a novel class of very promising polymeric materials for easy preparation of biochemical sensor matrices. apcns are characterised by nanoscopic phase separation between the hydrophilic and the hydrophobic phases. for medium ratios of conetwork composition, the domain ... | 2006 | 17019582 |
| zirconia nanoparticles enhanced grafted collagen tri-helix scaffold for unmediated biosensing of hydrogen peroxide. | a novel, biocompatible, thermally steady, and nontoxic zirconia enhanced grafted collagen tri-helix scaffold was prepared on a graphite electrode. this scaffold provided a microenvironment for loading biomolecules and helped to retain their natural structure. uv-vis spectroscopy and scanning electron microscopy were used to characterize the scaffold and the structure of immobilized biomolecules. using horseradish peroxidase (hrp) as an example, this scaffold accelerated its electron transfer and ... | 2006 | 17014135 |
| flow-through multianalyte chemiluminescent immunosensing system with designed substrate zone-resolved technique for sequential detection of tumor markers. | a novel flow-through immunosensing system for performing a multianalyte chemiluminescent determination in a single run was designed. a new analytical strategy of substrate zone-resolved technique was proposed. using carcinoma antigen 125 (ca 125) and carcinoembryonic antigen (cea) as model analytes, the capture antibodies for ca 125 and cea were immobilized on an ultrabind aldehyde-activated membrane to act as an immunoreactor, to which the mixture of ca 125, cea, and their corresponding tracers ... | 2006 | 17007526 |
| direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in sol-gel-derived ceramic-carbon nanotube nanocomposite film. | the sol-gel-derived ceramic-carbon nanotube (sgccn) nanocomposite film fabricated by doping multiwall carbon nanotubes (mwnts) into a silicate gel matrix was used to immobilize protein. the sgccn film can provide a favorable microenvironment for horseradish peroxidase (hrp) to perform direct electron transfer (det) at glassy carbon electrode. the hrp immobilized in the sgccn film shows a pair of well-defined redox waves and retains its bioelectrocatalytic activity to the reduction of o2 and h2o2 ... | 2007 | 16996257 |
| infrared absorption study of the heme pocket dynamics of carbonmonoxyheme proteins. | the temperature dependencies of the infrared absorption co bands of carboxy complexes of horseradish peroxidase (hrp(co)) in glycerol/water mixture at ph 6.0 and 9.3 are interpreted using the theory of optical absorption bandshape. the bands' anharmonic behavior is explained assuming that there is a higher-energy set of conformational substates (css(h)), which are populated upon heating and correspond to the protein substates with disordered water molecules in the heme pocket. analysis of the se ... | 2006 | 16980362 |
| nanophase-separated amphiphilic conetworks as versatile matrixes for optical chemical and biochemical sensors. | as a novel class of sensor matrixes, nanophase-separated amphiphilic polymeric conetworks (apcns) open a new dimension for optical chemical and biochemical sensing. these conetworks consist of a hydrophilic phase-we used poly(2-hydroxyethyl acrylate), poly(2-(dimethylamino)ethyl acrylate), or polycationic poly(2-(trimethylammonium)ethyl acrylate)-and of a hydrophobic phase-poly(dimethylsiloxane). sensors can be prepared by simple impregnation of the matrix. due to nanophase separation, there is ... | 2006 | 16970311 |
| qcm detection of dna targets with single-base mutation based on dna ligase reaction and biocatalyzed deposition amplification. | a novel biosensing technique for highly specific identification of gene with single-base mutation is proposed based on the implementation of the dna ligase reaction and the biocatalyzed deposition of an insoluble product. the target gene mediated deposition of an insoluble precipitate is then transduced by quartz crystal microbalance (qcm) measurements. in this method, the dna target hybridizes with a capture dna probe tethered onto the gold electrode and then with a biotinylated allele-specific ... | 2007 | 16963256 |
| novel composite fiber structures to provide drug/protein delivery for medical implants and tissue regeneration. | a novel class of bioresorbable composite (core/shell) fiber structures loaded with bioactive agents was developed and studied. these unique polymeric structures are designed to combine good mechanical properties with a desired controlled release profile, in order to serve as scaffolds for tissue regeneration applications and as basic elements of medical implants. these core/shell fiber structures were formed by "coating" core polymer fibers with drug/protein-containing poly(dl-lactic-co-glycolic ... | 2007 | 16956799 |
| independent roles for the dorsal paraflocculus and vermal lobule vii of the cerebellum in visuomotor coordination. | two distinct areas of cerebellar cortex, vermal lobule vii and the dorsal paraflocculus (dpfl) receive visual input. to help understand the visuomotor functions of these two regions, we compared their afferent and efferent connections using the tracers wheatgerm agglutinin horseradish peroxidase (wga-hrp) and biotinilated dextran amine (bda). the sources of both mossy fibre and climbing fibre input to the two areas are different. the main mossy fibre input to lobule vii is from the nucleus retic ... | 2007 | 16951960 |
| layer-by-layer hydroxymethyl ferrocene modified sensor for one-step flow/stop-flow injection amperometric immunoassay of alpha-fetoprotein. | a rapid one-step flow/stop-flow injection amperometric immunoassay for alpha-fetoprotein (afp) using a novel home-produced electrochemical sensor was proposed. the sensor was prepared using layer-by-layer adsorption of positively charged poly(allylamine) (paa) and negatively charged hydroxymethyl ferrocene on a screen-printed electrode (spe). the electrochemistry of the immobilized ferrocene moieties showed a surface-controlled electrode process. based on an electrochemical enzyme-linked immunoa ... | 2007 | 16950612 |
| signal enhancement of surface plasmon resonance immunoassay using enzyme precipitation-functionalized gold nanoparticles: a femto molar level measurement of anti-glutamic acid decarboxylase antibody. | colloidal gold nanoparticles (aunps) and precipitation of an insoluble product formed by hrp-biocatalyzed oxidation of 3,3'-diaminobenzidine (dab) in the presence of h2o2 were used to enhance the signal obtained from the surface plasmon resonance (spr) biosensor. the aunps were synthesized and functionalized with hs-oeg3-cooh by self assembling technique. thereafter, the hs-oeg3-cooh functionalized nanoparticles were covalently conjugated with horseradish peroxidase (hrp) and anti igg antibody t ... | 2007 | 16934448 |
| a third-generation h2o2 biosensor based on horseradish peroxidase-labeled au nanoparticles self-assembled to hollow porous polymeric nanopheres. | a novel third-generation biosensor for hydrogen peroxide (h2o2) was developed by self-assembling gold nanoparticles to hollow porous thiol-functionalized poly(divinylbenzene-co-acrylic acid) (dvb-co-aa) nanospheres. at first, a cleaned gold electrode was immersed in hollow porous thiol-functionalized poly(dvb-co-aa) nanosphere latex to assemble the nanospheres, then gold nanoparticles were chemisorbed onto the thiol groups of the nanospheres. finally, horseradish peroxidase (hrp) was immobilized ... | 2007 | 16930982 |
| screen-printed biosensors for glucose determination in grape juice. | an approach to the glucose determination by amperometric biosensing in wine industry applications is presented. integrated screen-printed biosensors based on horseradish peroxidase (hrp) and glucose oxidase (gox) have been developed. the experimental design methodology has been used to find the optimum conditions of the experimental variables, in such a way that a chronoamperometric response specific for glucose was recorded. under these conditions, repeatability and reproducibility of the modif ... | 2007 | 16930981 |
| sorption potential of moringa oleifera pods for the removal of organic pollutants from aqueous solutions. | moringa oleifera pods lamarck (drumstick or horseradish) is a multipurpose medium or small size tree from sub-himalayan regions of north-west india and indigenous to many parts of asia, africa, south america, and in the pacific and caribbean islands. its pods (mop) have been employed as an inexpensive and effective sorbent for the removal of organics, i.e., benzene, toluene, ethylbenzene and cumene (btec) from aqueous solutions using hplc method. effect of different parameters, i.e., sorbent dos ... | 2007 | 16930826 |
| receptive field structure-function correlates in developing turtle retinal ganglion cells. | mature retinal ganglion cells (rgcs) have distinct morphologies that often reflect specialized functional properties such as on and off responses. but the structural correlates of many complex receptive field (rf) properties (e.g. responses to motion) remain to be deciphered. in this study, we have investigated whether motion anisotropies (non-homogeneities) characteristic of embryonic turtle rgcs arise from immature dendritic arborization in these cells. to test this hypothesis, we have looked ... | 2006 | 16930408 |
| early neural activity and dendritic growth in turtle retinal ganglion cells. | early neural activity, both prenatal spontaneous bursts and early visual experience, is believed to be important for dendritic proliferation and for the maturation of neural circuitry in the developing retina. in this study, we have investigated the possible role of early neural activity in shaping developing turtle retinal ganglion cell (rgc) dendritic arbors. rgcs were back-labelled from the optic nerve with horseradish peroxidase (hrp). changes in dendritic growth patterns were examined acros ... | 2006 | 16930407 |
| inactivation of alpha1-antiproteinase induced by phenylbutazone: participation of peroxyl radicals and hydroperoxide. | to clarify the action of a side-effect of phenylbutazone, we investigated the inactivation of alpha(1)-antiproteinase induced by phenylbutazone in the presence of horseradish peroxidase (hrp) and h(2)o(2) (hrp-h(2)o(2)). the activity of alpha(1)-antiproteinase was rapidly lost during the interaction of phenylbutazone with hrp-h(2)o(2) under aerobic conditions. phenylbutazone showed a marked spectral change under aerobic conditions but not under anaerobic conditions. spin trap agents were very ef ... | 2006 | 16930300 |
| protecting the protectors: reducing the biological toxicity of uv sunscreens by zeolite encapsulation. | the phototoxic and photoallergic effects of the once popular uv sunscreen p-aminobanzoic acid are related, in part, to its ability to sensitize the formation of singlet oxygen as well as other reactive oxygen species. in this work we demonstrate that the sunscreen-photoinduced inactivation of a model protein, horseradish peroxidase, is reduced by approximately a factor of three when the sunscreen is encaspsulated in zeolite sodium y. these results provide evidence that using the technology of ze ... | 2013 | 16930095 |
| ultrafast pump-probe study of excited-state charge-transfer dynamics in umecyanin from horseradish root. | we have applied femtosecond pump-probe spectroscopy to investigate the excited-state dynamics of umecyanin from horseradish roots, by exciting its 600-nm ligand-to-metal charge-transfer band with a 15-fs pulse and probing over a broad range in the visible region. the decay of the pump-induced ground-state bleaching is modulated by clearly visible oscillations and occurs exponentially with a time constant depending on the observed spectral component of the transmission difference signal, ranging ... | 2006 | 16928024 |
| lateral spread of an amplification signal using an enzymatic system on a conductive surface. | in this letter, we report a novel signal amplification phenomenon that rapidly and dramatically increases both the magnitude and the lateral extent of the original signal. this phenomenon utilizes an enzyme immobilized on a conductive surface to generate amplified signals at locations remote from the original site of enzyme activity. the result is demonstrated on a microfluidic platform using the established precipitating enzyme-substrate system of horseradish peroxidase (hrp) and 3,3',5,5'-tetr ... | 2006 | 16922518 |
| horseradish peroxidase inhibition and antioxidant activity of ebselen and related organoselenium compounds. | horseradish peroxidase (hrp) inhibition and glutathione peroxidase (gpx) activities of ebselen and some related derivatives are described. these studies show that ebselen and ebselen ditelluride (ebte(2)) with significant antioxidant activity, inhibit the hrp-catalyzed oxidation reactions. in addition, inhibition of lipid peroxidation and singlet oxygen quenching studies were carried out. although the inhibition of hrp by ebselen is comparable with that of ebte(2), the inhibitory effect on gamma ... | 2006 | 16919452 |
| hydroxyl-containing antimony oxide bromide nanorods combined with chitosan for biosensors. | a hydroxyl-containing antimony oxide bromide (aob) nanorods was synthesized by a hydrothermal method. tem and sem images showed that the as-prepared aob nanorods were very copious with diameters of about 50 nm. the aob nanorods could be easily combined with biopolymer chitosan (chi) to form an organic-inorganic hybrid material, and a biocompatible, crack-free and porous chi-aob composite film could be readily obtained. horseradish peroxidase (hrp) was chosen as a model protein to construct a rea ... | 2006 | 16901539 |
| protonation and hydrogen-bonding state of the distal histidine in the co complex of horseradish peroxidase as studied by ultraviolet resonance raman spectroscopy. | ultraviolet resonance raman (uvrr) spectroscopy has been used to characterize the structure and hydrogen bonding state of the distal histidine (his42) in horseradish peroxidase (hrp) complexed with carbon monoxide (hrp-co). the hrp-co - hrp uvrr difference spectrum in d(2)o solution at pd 7.0 shows two positive peaks at 1408 and 1388 cm(-)(1), which are ascribable to medium-to-weak and strong hydrogen bonding states, respectively, of the protonated imidazolium side chain of his42 in hrp-co. both ... | 2006 | 16893167 |
| microsphere-based bioresorbable structures loaded with proteins for tissue regeneration applications. | novel bioresorbable fiber/microsphere composite structures loaded with proteins were developed and studied. these unique polymeric structures are designed to combine good mechanical properties with a desired controlled protein-release profile, in order to serve as scaffolds for tissue regeneration applications. the composite fiber structures were formed by "coating" poly(l-lactic acid) fibers with protein-containing poly(dl-lactic-co-glycolic acid) microspheres. the microspheres were prepared by ... | 2006 | 16883585 |
| novel bioresorbabale composite fiber structures loaded with proteins for tissue regeneration applications: microstructure and protein release. | novel bioresorbable core/shell composite fiber structures loaded with proteins were developed and studied. these unique polymeric structures are designed to combine good mechanical properties with a desired controlled protein-release profile, to serve as scaffolds for tissue regeneration applications. core/shell fiber structures were formed by "coating" poly(l-lactic acid) fibers with protein-containing poly(dl-lactic-co-glycolic acid) porous structures. shell preparation (coating) was performed ... | 2006 | 16883584 |
| multiplexed analyte and oligonucleotide detection on microarrays using several redox enzymes in conjunction with electrochemical detection. | we show that multiple enzyme tags may be used in an immunoassay format or for the detection of sequence-specific dna on microarrays. the assays may be multiplexed and monitored under separate solution and voltage differences. thus, the detection method relies on an electrochemical detection format, whereby multiple enzymes can be sensed. in our case we utilize horseradish peroxidase, laccase, and glucose dehydrogenase as enzymes attached to specific antibodies or to streptavidin. | 2006 | 16874377 |
| isolation and characterization of the first putative peroxidase gene from oilseed rape (brassica napus) which is highly homologous to hrpc. | a new gene, designated as bnprx (genbank accession no. dq078754), was isolated from oilseed rape (brassica napus) by smart rapid amplification of cdna ends (race). the full-length cdna is 1307 bp long and contains a 1062 bp open reading frame (orf), which encodes a 354 amino acid peroxidase precursor, with a 31 aa n-terminal signal peptide and a 15 aa c-terminal propeptide. the putative protein has a molecular weight of 38.86 kda and a calculated pi of 5.85. bnprx shares high identity with hrpc ... | 2006 | 16855866 |
| hofmeister effects in biology: effect of choline addition on the salt-induced super activity of horseradish peroxidase and its implication for salt resistance of plants. | the effect of choline addition on the salt-induced super activity of horseradish peroxidase (hrp) is investigated. hrp is presented in the literature as an efficient h(2)o(2) scavenger, and choline is the precursor of glycine betaine, a strong osmoprotectant molecule. both the regulations of h(2)o(2) and of osmoprotectant concentrations are implicated in plants in order to counteract salt-induced cell damage. for the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium ... | 2005 | 16853099 |