| plant peroxidases: substrate complexes with mechanistic implications. | plant peroxidases are capable of binding phenolic substrates, and it has been possible to crystallize complexes between horseradish peroxidase c (hrp c) and benzhydroxamic acid. the x-ray structures of the binary hrp c:ferulic acid complex and the ternary hrp c:cn(-):ferulic acid complex to 2.0 and 1.45 a resolution, respectively, have also been solved recently. ferulic acid is a naturally occurring phenolic compound found in the plant cell wall and it is an in vivo substrate for plant peroxidas ... | 2001 | 11356134 |
| comparison of photovoltaic behaviors for horseradish peroxidase and its mimicry by surface photovoltage spectroscopy. | surface photovoltage spectroscopy (sps) was chosen to study the photovoltaic behavior of horseradish peroxidase (hrp), hemin and immobilized hemin (poly(nipaam/mba/hemin)). different photovoltaic behaviors were observed in these three systems. in air, similar sps curves were found for hrp and poly(nipaam/mba/hemin) with different response intensities. however, poly(nipaam/mba/hemin) showed a wider changing range upon increasing the positive and negative bias to 1.0 v. the sps of hemin showed a t ... | 2001 | 11341942 |
| mediatorless biosensor for h(2)o(2) based on recombinant forms of horseradish peroxidase directly adsorbed on polycrystalline gold. | four forms of horseradish peroxidase (hrp) have been used to prepare peroxidase-modified gold electrodes for mediatorless detection of peroxide: native hrp, wild type recombinant hrp, and two recombinant forms containing six-his tag at the c-terminus and at the n-terminus, respectively. the adsorption of the enzyme molecules on gold was studied by direct mass measurements with electrochemical quartz crystal microbalance. all the forms of hrp formed a monolayer coverage of the enzyme on the gold ... | 2001 | 11339993 |
| one-step competitive immunoassay for cadmium ions: development and validation for environmental water samples. | a rapid, simple, and reliable competitive immunoassay was developed and validated for measurement of cd(ii) in environmental water samples. this assay employed a monoclonal antibody that recognizes cd(ii)-edta complexes as capture reagent and a cd(ii)-edta conjugate of horseradish peroxidase as an enzyme label. the assay depended on a competitive binding reaction between the enzyme conjugate and cd(ii)-edta complexes, derived from the environmental water sample, for the binding sites of the immo ... | 2001 | 11338607 |
| an essential role of active site arginine residue in iodide binding and histidine residue in electron transfer for iodide oxidation by horseradish peroxidase. | the objective of the present study is to delineate the role of active site arginine and histidine residues of horseradish peroxidase (hrp) in controlling iodide oxidation using chemical modification technique. the arginine specific reagent, phenylglyoxal (pgo) irreversibly blocks iodide oxidation following pseudofirst order kinetics with second order rate constant of 25.12 min(-1) m(-1). radiolabelled pgo incorporation studies indicate an essential role of a single arginine residue in enzyme ina ... | 2001 | 11330823 |
| evidence of neuroanatomical connection between the superior cervical ganglion and hypoglossal nerve in the hamster as revealed by tract-tracing and degeneration methods. | previous studies have shown the existence of a sympathetic component in some cranial nerves including the hypoglossal nerve. in this study, the horseradish peroxidase (hrp) tract-tracing retrograde technique and experimental degeneration method were used to elucidate the possible neuroanatomical relationship between the superior cervical ganglion (scg) and the hypoglossal nerve of hamsters. about 10% of the scg principal neurons were hrp positive following the tracer application to the trunk of ... | 2001 | 11327203 |
| flavonoids induced in cells undergoing nodule organogenesis in white clover are regulators of auxin breakdown by peroxidase. | it was tested whether flavonoids that specifically accumulate in cells undergoing early nodule organogenesis could affect auxin turnover by a peroxidase to explain local changes in auxin distribution that occur during nodule formation in white clover (trifolium repens cv. haifa). a fluorometric assay was developed to determine the kinetics of indoleacetic acid (iaa) breakdown rates by a horseradish peroxidase in vitro. three flavonoid compounds, which had previously been localized and identified ... | 2001 | 11326048 |
| phenylboronic acid-salicylhydroxamic acid bioconjugates. 1. a novel boronic acid complex for protein immobilization. | a chemical affinity system exhibiting antibody-like properties is described. the system exploits bioconjugates with appended phenylboronic acid (pba) moieties and a support-bound phenylboronic acid complexing reagent derived from salicylhydroxamic acid (sha) for protein immobilization on a chromatographic support. the structure of the pba.sha complex was characterized by 11b nmr and mass spectrometry and compared with complexes derived from model compounds. protein modification reagents were syn ... | 2012 | 11312684 |
| phosphate-binding loop and rab gtpase function: mutations at ser29 and ala30 of rab5 lead to loss-of-function as well as gain-of-function phenotype. | ras-like gtpases contain a structurally conserved gtp-binding domain. an important element of the gtp-binding domain is the phosphate-binding loop, which contains two gly residues (gly(12) and gly(13)) in ras. because the two gly residues are crucial for normal ras function, it is intriguing that they are not conserved in other ras-like gtpases, including the rab gtpases; for example, the equivalent residues in rab5 are ser(29) and ala(30). the present study builds on earlier biochemical charact ... | 2001 | 11311130 |
| graphite-teflon composite bienzyme electrodes for the determination of cholesterol in reversed micelles. application to food samples. | a bienzyme amperometric composite biosensor for the determination of free and total cholesterol in food samples is reported. cholesterol oxidase and horseradish peroxidase, together with potassium ferrocyanide as a mediator, are incorporated into a graphite-70% teflon matrix. the compatibility of this biosensor design with predominantly nonaqueous media allows the use of reversed micelles as working medium. the reversed micelles are formed with ethyl acetate as continuous phase (in which cholest ... | 2001 | 11305650 |
| a new rapid immunohistochemical staining technique using the envision antibody complex. | rapid immunohistochemical investigation, in addition to staining with hematoxylin and eosin, would be useful during intraoperative frozen section diagnosis in some cases. this study was undertaken to investigate whether the recently described envision system, a highly sensitive two-step immunohistochemical technique, could be modified for rapid immunostaining of frozen sections. forty-five primary antibodies were tested on frozen sections from various different tissues. after fixation in acetone ... | 2001 | 11304800 |
| ftir study of horseradish peroxidase in reverse micelles. | fourier transform infrared (ftir) method was used to study the secondary structures of horseradish peroxidase (hrp) in aqueous solution and in reverse micelles for the first time. results indicated that the structure of hrp in sodium bis(2-ethylhexy)sulfosuccinate (aot) reverse micelles was close to that in aqueous solution. in cetyltrimethylammonium bromide (ctab) and sodium dodecylfate (sds) reverse micelles the position of some bands changed. results indicated that the secondary structure had ... | 2001 | 11302746 |
| ultrastructural and permeability features of microvessels in the periventricular area of senescence-accelerated mice (sam). | brain transfer of intravenously injected horseradish peroxidase (hrp) and the ultrastructural features of the vessels were examined in periventricular areas in senescence-accelerated mice (samp8), which show age-related deficits in learning and memory, and senescence-accelerated resistant mice (samr1), which do not show age-related deficits. in all mice examined with light microscopy, staining reaction for hrp was seen in the periventricular area adjacent to the medial side of the lateral ventri ... | 2001 | 11301499 |
| oligosynaptic pathways possibly relaying visceral and/or gustatory information to the olfactory bulb in the hedgehog tenrec. | using anterograde and retrograde transport of wheat germ agglutinin we showed that the parabrachial nucleus, known to receive second order visceral and gustatory afferents, might project directly to the anterior olfactory nucleus which is connected with the olfactory bulb (ofb). only a small bulbar region is targeted directly by parabrachial fibers. this region is located immediately adjacent to the accessory ofb and may be closely related to, if not identical with the modified glomerular comple ... | 2001 | 11297822 |
| carbonmonoxy horseradish peroxidase as a function of ph and substrate: influence of local electric fields on the optical and infrared spectra. | infrared and optical spectra of carbonmonoxy horseradish peroxidase were monitored as a function of ph and substrate binding. the analyses of experimental results together with semiempirical calculations show that the co-porphyrin complex is sensitive to environmental changes. the electronic q(0,0) band of the porphyrin and the co stretching mode respond to external perturbations with different symmetry dependencies. in this way, the complex is nonisotropic, and the combined spectral analyses co ... | 2001 | 11297414 |
| activation of enzymes for nonaqueous biocatalysis by denaturing concentrations of urea. | urea is one of the most commonly used denaturants of proteins. however, herein we report that enzymes lyophilized from denaturing concentrations of aqueous urea exhibited much higher activity in organic solvents than their native counterparts. thus, instead of causing deactivation, urea effected unexpected activation of enzymes suspended in organic media. activation of subtilisin carlsberg (sc) in the organic solvents (hexane, tetrahydrofuran, and acetone) increased with increasing urea concentr ... | 2001 | 11295445 |
| chemiluminescent choline biosensor using histidine-modified peroxidase immobilised on metal-chelate substituted beads and choline oxidase immobilised on anion-exchanger beads co-entrapped in a photocrosslinkable polymer. | a novel sensing layer design is presented based on the non-covalent immobilisation of enzymes on derivatized sepharose beads subsequently entrapped in pva-sbq photopolymer. two different modified sepharose beads were used, ida- and deae-sepharose, for the immobilisation, respectively, of horseradish peroxidase (hrp) modified with histidine, and choline oxidase (chx). the hrp-ida-sepharose-based sensing layer was used in a flow injection analysis chemiluminescent system as the basis of an h2o2 bi ... | 2000 | 11286329 |
| does the photochemical conversion of colchicine into lumicolchicines involve triplet transients? a solvent dependence study. | beta- and gamma-lumicolchicines are photoproducts formed by the cycloisomerization of the tropolone ring of colchicine (col) alkaloids. the mechanism of the photoconversion, suggested to involve the triplet state, is examined here by studying the effect of the solvent polarity on the lumicolchicine photoisomer ratio. triplet col, detected by laser flash photolysis, is quenched by oxygen, but not by transtilbene or 1-methylnaphtalene. neither the quantum yield of conversion of col nor the photopr ... | 2001 | 11281015 |
| initial steps of ferulic acid polymerization by lignin peroxidase. | the major products of the initial steps of ferulic acid polymerization by lignin peroxidase included three dehydrodimers resulting from beta-5' and beta-beta'coupling and two trimers resulting from the addition of ferulic acid moieties to decarboxylated derivatives of beta-o-4'- and beta-5'-coupled dehydrodimers. this is the first time that trimers have been identified from peroxidase-catalyzed oxidation of ferulic acid, and their formation appears to be favored by decarboxylation of dehydrodime ... | 2001 | 11278569 |
| enzymatic activation of a new antitumour drug, 5-diethylaminoethylamino-8-hydroxyimidazoacridinone, c-1311, observed after its intercalation into dna. | the imidazoacridinone derivative, c-1311, is a new antitumour agent that exhibits strong antitumour activity against experimental colorectal cancer and has been selected for entry into clinical trial. the compound has previously been shown to have dna non-covalent binding properties in vitro and to bind irreversibly to dna of tumour cells. the latter effect has also been observed in a cell-free system, but only in the presence of activated enzymes. the present studies were aimed at finding out w ... | 2001 | 11266653 |
| a methylene blue-mediated enzyme electrode for the determination of trace mercury(ii), mercury(i), methylmercury, and mercury-glutathione complex. | a methylene blue-mediated enzyme biosensor has been developed for the detection of inhibitors including mercury(ii), mercury(i), methylmercury, and mercury-glutathione complex. the inhibition to horseradish peroxidase was apparently reversible and noncompetitive in the presence of hgcl2 in less than 8 s and irreversibly inactivated when incubated with different concentrations of hgcl2 for 1-8 min. the binding site of horseradish peroxidase with hgcl2 probably was a cysteine residue sh. mercury c ... | 2001 | 11261858 |
| a facile approach to immobilize protein for biosensor: self-assembled supported bilayer lipid membranes on glassy carbon electrode. | a kind of solid substrate, glassy carbon (gc) electrode, was selected to support self-assembled lipid layer membranes. on the surface of gc electrode, we made layers of dimyristoylphosphatidylcholine (dmpg, a kind of lipid). from electrochemical impedance experiments, we demonstrated that the lipid layers on the gc electrode were bilayer lipid membranes. we immobilized horseradish peroxidase (hrp) into the supported bilayer lipid membranes (s-blm) to develop a kind of mediator-free biosensor for ... | 2001 | 11261852 |
| trehalose effect on low temperature protein dynamics: fluctuation and relaxation phenomena. | we performed spectral diffusion experiments in trehalose-enriched glycerol/buffer-glass on horseradish peroxidase where the heme was replaced by metal-free mesoporphyrin ix, and compared them with the respective behavior in a pure glycerol/buffer-glass (schlichter et al., j. chem. phys. 2000, 112:3045-3050). trehalose has a significant influence: spectral diffusion broadening speeds up compared to the trehalose-free glass. this speeding up is attributed to a shortening of the correlation time of ... | 2001 | 11259314 |
| investigations of the alkaline and acid transitions of umecyanin, a stellacyanin from horseradish roots. | the effect of ph on cu(i) and cu(ii) umecyanin (ucu), a phytocyanin obtained from horseradish roots, has been studied by electronic and nmr spectroscopy and using direct electrochemical measurements. a pk(a) value of approximately 9.5-9.8 is observed for the alkaline transition in ucu(ii), and this leads to a slightly altered active site structure, as indicated by the changes in the paramagnetic 1h nmr spectrum. electrochemical studies show that the pk(a) value for this transition in ucu(i) is 9 ... | 2001 | 11258931 |
| direct antigen capture by soluble scfv antibodies. a method for detection, characterization, and determination of affinity. | for ease of detection, soluble forms of phage-displayed scfv antibodies are usually expressed with a tag, e.g., c-myc or his (histidine). the binding is then assayed by a monoclonal antibody to the tag. in this article, we describe the use of biotinylated antigen for detecting soluble scfv antibodies without utilizing the peptide tag detection system. the scfv antibodies were against the oncoplacental antigen heat-stable alkaline phosphatase (hsap). the method essentially consisted of either rev ... | 2001 | 11257803 |
| the energy level scheme for the ferryl heme in compound ii of the peroxidase-catalase family as determined from analysis of low-temperature magnetic circular dichroism. | the expressions for temperature-dependent magnetic circular dichroism (mcd) of the ferryl heme (fe(4+)por, s=1), which is a model of an intermediate product of the catalytic cycle of heme enzymes (compound ii), have been derived in the framework of a two-term model. theoretical predictions for the temperature and magnetic field dependence of mcd intensity of the ferryl heme are compared with those of the high-spin and low-spin ferric heme. analysis of reported mcd spectra of myoglobin peroxide [ ... | 2001 | 11245808 |
| gene directed enzyme/prodrug therapy of cancer: historical appraisal and future prospectives. | gene therapy of cancer is a novel approach with the potential to selectively eradicate tumour cells, whilst sparing normal tissue from damage. in particular, gene-directed enzyme prodrug therapy (gdept) is based on the delivery of a gene that encodes an enzyme which is non-toxic per se, but is able to convert a prodrug into a potent cytotoxin. several gdept systems have been investigated so far, demonstrating effectiveness in both tissue culture and animal models. based on these encouraging resu ... | 2001 | 11241346 |
| molecular weight distribution and structural characteristics of polymers obtained from acid soluble lignin treated by oxidative enzymes. | brown precipitates were obtained by polymerization of low molecular weight lignin fragments contained in a model effluent. polymerization reactions were initiated by potato-polyphenoloxidase (ppo) or horseradish peroxidase/h(2)o(2) system (hrp/h(2)o(2)). the insolubilization processes occurred after a molecular weight increase of the lignin, as shown by gel permeation chromatography (gpc). the effect of reaction time, ph and amount of soluble lignin per unit of enzyme activity on the molecular w ... | 2001 | 11240184 |
| treatment of a foul condensate from kraft pulping with horseradish peroxidase and hydrogen peroxide. | foul condensates originating from the kraft recovery process contain phenolic compounds whose removal might render these process streams more useful for reuse in other plant operations or more amenable to biological degradation. treatment of a foul condensate with horseradish peroxidase and h2o2 selectively targeted phenolic compounds resulting in a reduction of the total phenols concentration below 1 mg/l as well as a substantial toxicity drop as measured using the microtox assay; however, only ... | 2001 | 11229003 |
| development and application of an enzyme-linked immunosorbent assay for the analysis of hydrolyzed fumonisins. | polyclonal antibodies against hydrolyzed fumonisin b1 (hfb1) were prepared by immunization of rabbits with a keyhole limpet hemocyanin conjugate coupled by glutaraldehyde. sensitivity and specificity of these antibodies were tested in a direct competitive enzyme-linked immunosorbent assay (elisa), in which a hfb1-horseradish peroxidase conjugate prepared by reductive alkylation served as the labeled antigen. a direct competitive elisa for the quantitative determination of hfb1 in corn-based food ... | 2001 | 23605774 |
| a general affinity method to purify peroxidase-tagged antibodies. | antibodies tagged with enzymes, e.g. horseradish peroxidase (hrpo) are used extensively in a broad range of immunoassay, immunohistochemical, and prodrug-based immunotherapeutic applications. these antibodies may be polyclonal, monoclonal, bispecific or genetically engineered in origin. often, purification of the antibody is the single greatest obstacle to obtaining immunoprobes with high specific activity [milstein and cuello, nature 305 (1983) 537]. we have circumvented this problem by utilisi ... | 2001 | 11226461 |
| spectroelectrochemical investigation of direct electron transfer between resting horseradish peroxidase and its oxidation states promoted by dna. | direct electron transfer between resting horseradish peroxidase (hrp) and its oxidation states was observed at a gold mesh electrode in a spectroelectrochemical cell in the presence of dna. the conversion between hrp and the oxidized species induced electrochemically was found to be reversible and parallel to that initiated chemically. dna played an important role as electron carrier and promoted the electron transfer between hrp and the electrodes. voltammetric results and cd spectra indicated ... | 2000 | 11225878 |
| enzyme-amplified aequorin-based bioluminometric hybridization assays. | the sensitivity of aequorin-based bioluminometric hybridization assays was enhanced by introducing, enzymically, multiple aequorin labels per dna hybrid. the target dna was hybridized in microtiter wells with an immobilized capture probe and a digoxigenin-labeled detection probe. the hybrids were reacted with an anti-digoxigenin antibody conjugated to horseradish peroxidase. peroxidase catalyzed the oxidation of digoxigenin-tyramine by hydrogen peroxide, resulting in the attachment of multiple d ... | 2001 | 11217784 |
| biosensor for determination of glucose and sucrose in fruit juices by flow injection analysis. | glucose and sucrose were measured with an amperometric method by using the flow injection analysis technique. a carbon paste electrode with a renewable surface containing glucose oxidase, horseradish peroxidase, and ferrocene was used in combination with the soluble enzymes invertase and mutarotase. the effect of invertase, mutarotase, and ascorbic acid on the electrode response was examined. glucose and sucrose concentrations were determined with < 3% errors. the proposed method for glucose and ... | 2013 | 11209461 |
| fiberoptic biosensors based on chemiluminescent reactions. | the chemiluminescence of luminol in the presence of h2o2 has been exploited to develop fiberoptic biosensors associated with flow injection analysis systems. a chlorophenol sensor was developed based on the ability of certain halophenols to enhance the peroxidase-catalyzed luminol chemiluminescence. horseradish peroxidase immobilized on a collagen membrane was used. ten chlorophenols have been tested with this chemiluminescent-based sensor. the lower detection limit was obtained with 4-chloro-3- ... | 2013 | 11209455 |
| intraretinal axon diameters of a new world primate, the marmoset (callithrix jacchus). | previously, measurements of retinal ganglion cell axon diameter have been used to make inferences about the physiology and clinical pathology of the visual pathway. however, few of these studies were able to unequivocally relate axon diameter to retinal ganglion cell type and other associated measurements. in this and our previous study we have examined intraretinal axon diameters to determine if differences in axon diameter may help to explain conduction velocity measurements found previously. | 2000 | 11202465 |
| development and comparison of biosensors for in-vivo applications. | electrochemical biosensors have been of increasing interest, especially those developed to be directly applied in diagnostic areas, such as neuroscience. we have been interested in developing a range of biosensors for monitoring glucose, lactate, pyruvate, and glutamate in order to study on-line both brain function in the laboratory and to monitor brain health in neurointensive care. for a biosensor to function effectively in these situations, it has to combine the following characteristics: qui ... | 2000 | 11197486 |
| direct heterogeneous electron transfer of recombinant horseradish peroxidases on gold. | clean polycrystalline gold electrodes were modified with native glycosylated horseradish peroxidases (hrp) or two different recombinant (carbohydrate free) hrps; recombinant wild-type hrp (rec-hrp) and recombinant hrp containing a six histidine-tag at the c-terminus of the polypeptide chain (rec-hrp-his), respectively. only the electrodes modified with the recombinant hrps exhibited high current responses to h2o2 due to relatively rapid direct electron transfer (et) between recombinant hrp and g ... | 2000 | 11197485 |
| liposomes labeled with biotin and horseradish peroxidase: a probe for the enhanced amplification of antigen--antibody or oligonucleotide--dna sensing processes by the precipitation of an insoluble product on electrodes. | liposomes labeled with biotin and the enzyme horseradish peroxidase (hrp) are used as a probe to amplify the sensing of antigen-antibody interactions or oligonucleotide-dna binding. the hrp-biocatalyzed oxidation of 4-chloro-1-naphthol (1) in the presence of h2o2, and the precipitation of the insoluble product 2 on electrode supports, are used as an amplification route for the sensing processes. the anti-dinitrophenyl antibody (dnp-ab) is sensed by a dinitrophenyl-l-cysteine antigen monolayer as ... | 2001 | 11195517 |
| peroxidase-catalyzed oxidation of ascorbate. structural, spectroscopic and mechanistic correlations in ascorbate peroxidase. | ascorbate-dependent peroxidase activity was first reported in 1979 (groden and beck, 1979; kelly and latzko, 1979) and ascorbate peroxidase (apx) is, therefore, a relative newcomer to the peroxidase field--horseradish (hrp) and cytochrome c (ccp) peroxidases were, for example, first identified in 1903 (bach and chodat, 1903) and 1940 (altschul et al., 1940) respectively. the apx area was reviewed by dalton in 1991 (dalton, 1991): at that time, there was very little detailed kinetic, spectroscopi ... | 2000 | 11192727 |
| mononuclear (nitrido)iron(v) and (oxo)iron(iv) complexes via photolysis of [(cyclam-acetato)feiii(n3)]+ and ozonolysis of [(cyclam-acetato)feiii(o3scf3)]+ in water/acetone mixtures. | reaction of the monoanionic, pentacoordinate ligand lithium 1,4,8,11-tetraazacyclotetradecane-1-acetate, li(cyclam-acetate), with fecl3 yields, upon addition of kpf6, [(cyclam-acetato)fecl]pf6 (1) as a red microcrystalline solid. addition of excess nan3 prior to addition of kpf6 yields the azide derivative [(cyclam-acetato)fen3]pf6 (2a) as orange microcrystals. the x-ray crystal structure of the azide derivative has been determined as the tetraphenylborate salt (2b). reaction of 1 with silver tr ... | 2000 | 11187471 |
| a di-leucine sequence and a cluster of acidic amino acids are required for dynamic retention in the endosomal recycling compartment of fibroblasts. | insulin-regulated aminopeptidase (irap), a transmembrane aminopeptidase, is dynamically retained within the endosomal compartment of fibroblasts. the characteristics of this dynamic retention are rapid internalization from the plasma membrane and slow recycling back to the cell surface. these specialized trafficking kinetics result in <15% of irap on the cell surface at steady state, compared with 35% of the transferrin receptor, another transmembrane protein that traffics between endosomes and ... | 2001 | 11179421 |
| catalase-like activity of horseradish peroxidase: relationship to enzyme inactivation by h2o2. | h2o2 is the usual oxidizing substrate of horseradish peroxidase c (hrp-c). in the absence in the reaction medium of a one-electron donor substrate, h2o2 is able to act as both oxidizing and reducing substrate. however, under these conditions the enzyme also undergoes a progressive loss of activity. there are several pathways that maintain the activity of the enzyme by recovering the ferric form, one of which is the decomposition of h2o2 to molecular oxygen in a similar way to the action of catal ... | 2001 | 11171085 |
| topographic patterns of v2 cortical connections in a prosimian primate (galago garnetti). | topographic patterns of cortical connections of the second visual area (v2) were examined in a lorisiform prosimian primate (galago garnetti). up to five different tracers were injected into dorsal and ventral v2. tracers included wheat germ agglutinin conjugated to horseradish peroxidase (wga-hrp) and up to four fluorochromes. tracer injections consistently labeled neurons and terminals in primary visual cortex (v1), v2, the middle temporal area (mt), and the dorsolateral visual area (dl). labe ... | 2001 | 11169997 |
| structural and physiological properties of connections between individual reticulospinal axons and lumbar motoneurons of the frog. | although the direct, monosynaptic influence of brainstem projections onto motoneurons is well-known, detailed morphological studies on the synaptic contact systems and a correlation with their functional properties are largely lacking. in this work, 43 pairs, each formed by a reticulospinal fiber contacting a lumbar motoneuron, were identified and studied electrophysiologically. four of these were successfully labeled intracellularly with horseradish peroxidase (hrp) or neurobiotin and reconstru ... | 2001 | 11169478 |
| vestibular efferent neurons project to the flocculus. | a bilateral projection from the vestibular efferent neurons, located dorsal to the genu of the facial nerve, to the cerebellar flocculus and ventral paraflocculus was demonstrated. efferent neurons were double-labeled by the unilateral injections of separate retrograde tracers into the labyrinth and into the floccular and ventral parafloccular lobules. efferent neurons were found with double retrograde tracer labeling both ipsilateral and contralateral to the sites of injection. no double labeli ... | 2001 | 11166721 |
| a comparison of silver ion to streptavidin coated microplates. | direct comparisons are made between covalently linked streptavidin and silver ion coated microplates. both coatings can immobilize biotinylated molecules. silver ion coated microplate wells can immobilize 1.8 times higher amounts of biotin labeled horseradish peroxidase. the quantitation range and capacity for the capture of horseradish peroxidase using biotin labeled horseradish peroxidase are also greater for silver ion coated microplates. approximately twice as many anti-horseradish peroxidas ... | 2001 | 11165340 |
| the mauthner cell and other identified neurons of the brainstem escape network of fish. | this paper reviews the development of our research on the motor consequences of mauthner cell function and related brainstem neurons. these cells activate fast-start responses such as seen in fishes escaping from predatory attacks. our goal was to devise a neuroethological theory of fish escape that accurately reconciled the underlying neural function with a correct concept of the motor act. the identified neuron concept of invertebrates greatly influenced the initial studies. horseradish peroxi ... | 2001 | 11163687 |
| preparation and initial characterization of the compound i, ii, and iii states of iron methylchlorin-reconstituted horseradish peroxidase and myoglobin: models for key intermediates in iron chlorin enzymes. | to better understand the spectral properties of high valent and oxyferrous states in naturally occurring iron chlorin-containing proteins, we have prepared the oxoferryl compound i derivative of iron methylchlorin-reconstituted horseradish peroxidase (mechl-hrp) and the compound ii and oxyferrous compound iii states of iron mechl-reconstituted myoglobin. initial spectral characterization has been carried out with uv-visible absorption and magnetic circular dichroism. in addition, the peroxidase ... | 2000 | 11162466 |
| energy selection is not correlated in the qx and qy bands of a mg-porphyrin embedded in a protein. | the qx-qy splitting observed in the fluorescence excitation spectra of mg-mesoporphyrin-ix substituted horseradish peroxidase (mgmp-hrp) and of its complex with naphthohydroxamic acid (nha) was studied by spectral hole burning techniques. the width of a hole directly burnt in the qy band and that of a satellite hole indirectly produced in qy as a result of hole burning in qx was compared. we also studied the dependence of the satellite hole in the qy band on the burning frequency used in the qx ... | 2001 | 11159420 |
| beta(1,2)-xylose and alpha(1,3)-fucose residues have a strong contribution in ige binding to plant glycoallergens. | primary structures of the n-glycans of two major pollen allergens (lol p 11 and ole e 1) and a major peanut allergen (ara h 1) were determined. ole e 1 and ara h 1 carried high mannose and complex n-glycans, whereas lol p 11 carried only the complex. the complex structures all had a beta(1,2)-xylose linked to the core mannose. substitution of the proximal n-acetylglucosamine with an alpha(1, 3)-fucose was observed on lol p 11 and a minor fraction of ole e 1 but not on ara h 1. to elucidate the s ... | 2000 | 10753962 |
| regulation of tight junction permeability and occludin phosphorylation by rhoa-p160rock-dependent and -independent mechanisms. | in epithelial and endothelial cells, tight junctions regulate the paracellular permeability of ions and proteins. disruption of tight junctions by inflammation is often associated with tissue edema, but regulatory mechanisms are not fully understood. using ecv304 cells as a model system, lysophosphatidic acid and histamine were found to increase the paracellular permeability of the tracer horseradish peroxidase. cytoskeletal changes induced by these agents included stimulation of stress fiber fo ... | 2001 | 11139571 |
| the effects of nitric oxide on the oxidations of l-dopa and dopamine mediated by tyrosinase and peroxidase. | the effects of nitric oxide (no) on both tyrosinase/o(2)- and horseradish peroxidase/h(2)o(2)-mediated oxidations of dopamine and its o-dihydric phenol precursor l-dopa were compared with autoxidative processes and quantitatively assessed by oxidative and reductive electrochemical detection systems. in peroxidase/h(2)o(2)/no-catalyzed reactions, significantly more substrate was oxidized than in the corresponding control incubations lacking no. in tyrosinase/o(2)/no-promoted reactions the total a ... | 2001 | 11136730 |
| enzyme inactivation by tio2 photosensitization. | the enzyme horseradish peroxidase is extensively inactivated by uva exposure in the presence of tio2, a common ingredient of sunscreens and cosmetics. the effect is attributed to the generation of reactive oxygen species, as indicated by the inactivation enhancement observed in the presence of air. | 2000 | 11154086 |
| anti-tnp monoclonal antibodies as reagents for enzyme immunoassay (elisa). | the aim of this study was to produce anti-tnp monoclonal antibodies (mabs) that could be conjugated and used for the detection of antigen-antibody reactions, in which the antigen specific-antibody had been previously bound to trinitrophenyl (tnp). for hybridoma production, sp2/0-ag14 cells were fused with spleen cells from mice previously immunized with tnp-ovalbumin (tnp-ova). after 10 days, enzyme-linked immunoadsorbent assay (elisa) was used to detect anti-tnp antibodies in the supernatants, ... | 2000 | 11152399 |
| application of marcus theory of electron transfer for the reactions between hrp compound i and ii and 2,4-disubstituted phenols. | reactions between horseradish peroxidase (hrp) compound i and ii and some natural phenolic antioxidants were studied at ph 7. the bimolecular rate constants for these reactions were determined using a sequential mixing stopped-flow spectrometer. the rate constants for the reactions of compound i were found to be two orders of magnitude higher than those for compound ii. the phenols under study showed a significant difference in their one-electron reduction potential values. as the rate constants ... | 2000 | 11152266 |
| innervation of the caudal denervated ventral roots and their target muscles by the rostral spinal motoneurons after implanting a nerve autograft in spinal cord-injured adult marmosets. | the authors conducted a study to determine the effects of using a nerve autograft (nag) to promote and guide axonal regrowth from the rostral spinal cord to the caudal lumbar ventral nerve roots to restore hindlimb motor function in adult marmosets after lower thoracic cord injury. | 2001 | 11147873 |
| a method to measure antioxidant activity in organic media: application to lipophilic vitamins. | the 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) radical (abts(.+)) can be generated by the enzymatic system formed by hydrogen peroxide and horseradish peroxidase in an organic medium. the abts radical is easily generated in acidified ethanol medium in about 100 s with a stability of 1.7 x 10(-3) (-deltaabs/min) monitored at 730 nm. other organic solvents, such as methanol or acetone, have lower radical generation times but the radical is less stable. the addition of trolox or a lipo ... | 2000 | 11140747 |
| effects of peroxidase therapy on functional state of the liver and phagocytes and blood cell counts in mice with experimental leprosy. | we studied the effects of long-term therapy with horseradish peroxidase administered orally to mice with experimental leprosy. horseradish peroxidase stimulated phagocyte myeloperoxidase activity that correlated with their functional activity, reduced leukocytosis, and produced no adverse effects on the liver. | 2000 | 11140586 |
| basic immunocytochemistry for light microscopy. | immunocytochemistry may be defined as the identification of a cell- or tissue-bound antigen in situ, by means of a specific antibody-antigen reaction, tagged microscopically by a visible label. successful immunocytochemistry therefore requires (1) preservation of the antigen in a form that is recognizable by the antibody, (2) a suitable antibody, and (3) an appropriate label. the basic technique was first described by coons and colleagues (1-3), who employed antibody directly labeled with a fluo ... | 2001 | 21340888 |
| western blotting. | western blotting is employed for the detection of proteins and other macromolecules immobilized on nitrocellulose membranes. this rapid and sensitive method enables the identification and quantification of a specific protein from cell lysates or a mixture of proteins. following the resolution on denaturing sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis (sds-page), the constituent polypeptides are transferred electrophoretically to a nitrocellulose membrane (1). the membrane is i ... | 2001 | 21331721 |
| thermally induced conformational changes in horseradish peroxidase. | detailed differential scanning calorimetry (dsc), steady-state tryptophan fluorescence and far-uv and visible cd studies, together with enzymatic assays, were carried out to monitor the thermal denaturation of horseradish peroxidase isoenzyme c (hrpc) at ph 3.0. the spectral parameters were complementary to the highly sensitive but integral method of dsc. thus, changes in far-uv cd corresponded to changes in the overall secondary structure of the enzyme, while that in the soret region, as well a ... | 2001 | 11121111 |
| myeloperoxidase-catalyzed oxidation of melatonin by activated neutrophils. | in the presence of hydrogen peroxide, horseradish peroxidase (hrp) catalyzes the production of n(1)-acetyl-n(2)-formyl-5-methoxykynuramine from melatonin. this reaction consumes oxygen and exhibits chemiluminescence in the 440-540 nm region. the excited cleavage product derived from the thermolysis of an intermediate dioxetane is suggested to be the emitting species. chemiluminescence and the indole ring cleavage product were also observed when hrp/h(2)o(2) was replaced by phorbol myristate acet ... | 2000 | 11118341 |
| arabidopsis atp a2 peroxidase. expression and high-resolution structure of a plant peroxidase with implications for lignification. | lignins are phenolic biopolymers synthesized by terrestrial, vascular plants for mechanical support and in response to pathogen attack. peroxidases have been proposed to catalyse the dehydrogenative polymerization of monolignols into lignins, although no specific isoenzyme has been shown to be involved in lignin biosynthesis. recently we isolated an extracellular anionic peroxidase, atp a2, from rapidly lignifying arabidopsis cell suspension culture and cloned its cdna. here we show that the atp ... | 2000 | 11117266 |
| mice lacking renal chloride channel, clc-5, are a model for dent's disease, a nephrolithiasis disorder associated with defective receptor-mediated endocytosis. | nephrolithiasis (kidney stones) affects 5-10% of adults and is most commonly associated with hypercalciuria, which may be due to monogenic renal tubular disorders. one such hypercalciuric disorder is dent's disease, which is characterized by renal proximal tubular defects that include low molecular weight proteinuria, aminoaciduria and glycosuria, together with rickets in some patients. dent's disease is due to inactivating mutations of the renal-specific voltage-gated chloride channel, clc-5, w ... | 2000 | 11115837 |
| purification and stability of peroxidase of african oil palm elaies guineensis. | in the previous work, after screening tropical plants (43 species) for peroxidase activity, high activity has been detected in leaves of some palms and especially african oil palm elaeis guineensis. this palm is widely cultivated in colombia and presents a promising source for the industrial production of peroxidase. the initial enzyme isolation included homogenization and extraction of pigments using aqueous two phase polymer system. initially, traditional system, formed by polyethyleneglycol/k ... | 2000 | 11105241 |
| polymerization of humic substances by an enzyme-catalyzed oxidative coupling. | a novel understanding of the structural features of humic substances supports the self-assembly supramolecular association of relatively small molecules rather than their polymeric nature. an increase in the conformational stability of humus may thus be achieved through promotion of intermolecular covalent bondings between heterogeneous humic molecules by an enzyme-catalyzed oxidative reaction. we present evidence from high performance size exclusion chromatography (hpsec) and diffuse reflectanc ... | 2000 | 11091961 |
| metal coordination influences substrate binding in horseradish peroxidase. | to clarify the role of metal ion coordination in horseradish peroxidase c (hrpc), the effect of pressure and of an externally applied electric field on spectral holes was compared for both metal-free and mg-mesoporphyrin-substituted horseradish peroxidase c (mp-hrp and mgmp-hrp), as affected by the binding of 2-naphthohydroxamic acid (nha). the data are compared to earlier studies performed on the same derivatives. results obtained for mp-hrp show the presence of a predominant mp tautomer, as we ... | 2000 | 11081404 |
| horseradish peroxidase binding to intestinal brush-border membranes of cyprinus carpio. identification of a putative receptor. | morphologic studies have shown that the classic endocytosis tracer horseradish peroxidase (hrp) is actively internalized by vesicular transport in the carp intestine, suggesting the existence of specific binding sites in the apical membrane of enterocytes. the aim of the present study was to develop an in vitro binding assay using isolated carp intestinal brush-border membranes (bbm) to demonstrate and characterize these specific hrp binding sites. the results obtained show that hrp binding to b ... | 2000 | 11074599 |
| scavenging of h2o2 and production of oxygen by horseradish peroxidase. | peroxidases catalyze many reactions, the most common being the utilization of h2o2 to oxidize numerous substrates (peroxidative mode). peroxidases have also been proposed to produce h2o2 via utilization of nad(p)h, thus providing oxidant either for the first step of lignification or for the "oxidative burst" associated with plant-pathogen interactions. the current study with horseradish peroxidase characterizes a third type of peroxidase activity that mimics the action of catalase; molecular oxy ... | 2000 | 11068874 |
| ionic strength and ph effect on the fe(iii)-imidazolate bond in the heme pocket of horseradish peroxidase: an epr and uv-visible combined approach. | the effects of chloride, dihydrogenphosphate and ionic strength on the spectroscopic properties of horseradish peroxidase in aqueous solution at ph=3.0 were investigated. a red-shift (lambda=408 nm) of the soret band was observed in the presence of 40 mm chloride; 500 mm dihydrogenphosphate or chloride brought about a blue shift of the same band (lambda=370 nm). the epr spectrum of the native enzyme at ph 3.0 was characterized by the presence of two additional absorption bands in the region arou ... | 2000 | 11065189 |
| reactivity of horseradish peroxidase compound ii toward substrates: kinetic evidence for a two-step mechanism. | transient kinetic analysis of biphasic, single turnover data for the reaction of 2,2'-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] (abts) with horseradish peroxidase (hrpc) compound ii demonstrated preequilibrium binding of abts (k(+5) = 7.82 x 10(4) m(-)(1) s(-)(1)) prior to rate-limiting electron transfer (k(+6) = 42.1 s(-)(1)). these data were obtained using a stopped-flow method, which included ascorbate in the reaction medium to maintain a low steady-state concentration of abts (pseudo- ... | 2000 | 11052672 |
| [effect of surface-active agents (saa) on peroxidase activity. iii. effect of nonionic saa]. | the effect of a series of nonionic surfactants on the initial rate of the peroxide oxidation of 5-aminosalicylic acid in solution catalyzed by horseradish peroxidase was studied. as the surfactant concentration increases, the peroxidation rate first increases, then decreases, and the increase/decrease cycle is repeated. the primary increase may be induced by a change in properties of the medium under the action of surfactants, and the following decrease, by the enzyme inhibition. the secondary i ... | 2000 | 11040998 |
| determination of matrix metalloproteinase activity using biotinylated gelatin. | matrix metalloproteinases (mmps) and, specifically, mmp-2 (gelatinase a) and mmp-9 (gelatinase b) are strongly associated with malignant progression and matrix remodeling. these enzymes are a subject of intensive studies involving screening of comprehensive chemical libraries of synthetic inhibitors. there is no simple method available for measurement of activity of gelatinases and related mmps. here, we report a simple, inexpensive, and highly sensitive assay for mmp activity. the assay perform ... | 2000 | 11038285 |
| ascorbate-dependent recycling of the vitamin e homologue trolox by dihydrolipoate and glutathione in murine skin homogenates. | in the redox antioxidant network, dihydrolipoate can synergistically enhance the ascorbate-dependent recycling of vitamin e. since the major endogenous thiol antioxidant in biological systems is glutathione (gsh) it was of interest to compare the effects of dihydrolipoate with gsh on ascorbate-dependent recycling of the water-soluble homologue of vitamin e, trolox, by electron spin resonance (esr). trolox phenoxyl radicals were generated by a horseradish peroxidase (hrp)-hydrogen peroxide (h2o2) ... | 2000 | 11035266 |
| histochemical and immunohistochemical differential diagnosis of amyloidosis--a brief illustrated essay and personal experience with romhányi's method. | the histochemical and immunohistochemical differential diagnosis of amyloidosis in surgical pathology in a referral center is presented. different forms of amyloidosis are considered e.g. systemic generalized amyloidosis: secondary (aa), primary (al), senile, hemodialysis-associated, hereditary and organ (tissue)-limited (localized) amyloidosis: cerebral, dystrophic (age-related, so-called "senile"), endocrine-related, localized to tumours, focal (concentrated secretion), and isolated plasma cel ... | 2000 | 11019862 |
| fibrin encapsulated liposomes as protein delivery system. studies on the in vitro release behavior. | the efficacy of biologically active proteins in medical therapy depends on the development of suitable drug delivery systems. these delivery systems need to overcome the severe problems connected with the use of proteins such as their usually short half lives in body fluids and their susceptibility to proteolysis and denaturation. our delivery system combines two widespread devices by encapsulating liposomes containing the model protein horseradish peroxidase (hrp) inside the biopolymer fibrin. ... | 2000 | 11018554 |
| chemical grafting of molecularly imprinted homopolymers to the surface of microplates. application of artificial adrenergic receptor in enzyme-linked assay for beta-agonists determination. | a technique for coating of microplate wells with a molecularly imprinted polymer (mip), specific for epinephrine, is presented. 3-aminophenylboronic acid was polymerized in the presence of epinephrine using oxidation of the monomer by ammonium persulfate. this process resulted in the grafting of a thin polymer layer onto the polystyrene surface of the microplates. the polymer affinity was determined by an enzyme-linked assay using a conjugate of horseradish peroxidase and norepinephrine (hrp-n). ... | 2000 | 11008773 |
| a three-cascaded-enzymes biosensor to determine lactose concentration in raw milk. | the increasing demand for on-line measurement of milk composition directs science and industry to search for practical solutions, and biosensors may be a possibility. the specific objective of this work was to develop an electrochemical biosensor to determine lactose concentration in fresh raw milk. the sensor is based on serial reactions of three enzymes--beta-galactosidase, glucose oxidase, and horseradish peroxidase--immobilized on a glassy carbon electrode. the sequential enzymatic reactions ... | 2000 | 11003221 |
| peroxidase-catalyzed asymmetric sulfoxidation in organic solvents versus in water. | peroxidase-catalyzed asymmetric sulfoxidations, while synthetically attractive, suffer from relatively low reaction rates due to poor substrate solubilities in water and from appreciable spontaneous oxidation of substrates (especially aryl alkyl sulfides) with h(2)o(2). in this work, we found that both of these shortcomings could be alleviated by switching from aqueous solutions to certain nearly anhydrous (99.7%) organic solvents as sulfoxidation reaction media. the rates of spontaneous oxidati ... | 2000 | 10992240 |
| surfactant-lactoperoxidase complex catalytically active in organic media. | a surfactant-lactoperoxidase (lpo) complex catalytically active in organic solvents was developed by the emulsion coating method. the oxidation of 2,6-dimethoxyphenol (2,6-dmp) was conducted by the surfactant-lpo complex in organic media. the lpo complex efficiently catalyzed the oxidation of 2,6-dmp in various organic solvents, although lyophilized lpo did not display the catalytic activity at all. to optimize the preparation and reaction conditions for the surfactant-lpo complex, we examined t ... | 2000 | 10959083 |
| thermometric sensing of peroxide in organic media. application to monitor the stability of rbp-retinol-hrp complex. | the stability of horseradish peroxidase (hrp) in aqueous and organic solvents is applied to develop a simple thermometric procedure to detect the binding of retinoic acid-hrp conjugate to retinol binding protein (rbp). butanone peroxide (bp) in organic phase and hydrogen peroxide in aqueous phase is detected thermometrically on a hrp column, immobilized by cross-linking with glutaraldehyde on controlled pore glass (cpg). acetone, acetonitrile, methanol, and 2-butanol are used for detection of bp ... | 2000 | 10952525 |
| an improved nonfluorescent detection system for in situ hybridization in plants. | molecular cytogenetics, particularly the localization of dna sequences by in situ hybridization, has increased our understanding about the genomic structure of plants and animals. we demonstrate here the application of an improved nonfluorescent in situ hybridization system detection (dako genpoint system) to plant chromosomes. using this system, highly repetitive 18s-25s rrna genes were mapped on vicia faba chromosomes (2n = 12). the modified method of this horseradish peroxidase based enzymati ... | 2000 | 10941508 |
| nicotinamide adenine dinucleotide species in the horseradish peroxidase-oxidase oscillator. | nadh chemistry ancillary to the oscillatory peroxidase-oxidase (po) reaction has been reexamined. previously, (nad)2 has been thought of as a terminal, inert product of the po reaction. we now show that (nad)2 is a central reactant in this system. although we found traces of the dimer after several hours of the po reaction, no accumulation of the dimer occurred, regardless of the reaction time or the number of oscillations. (nad)2 can convert horseradish peroxidase (hrp) compound i (cpi) to comp ... | 2000 | 10931183 |
| reactions of pholasin with peroxidases and hypochlorous acid. | the ability of myeloperoxidase (mpo) and horseradish peroxidase (hrp) to induce chemiluminescence (cl) in pholasin (knight scientific, plymouth, uk), the photoprotein of the common piddock pholas dactylus, was studied. the oxidation of pholasin by compound i or ii of hrp induced an intense light emission, whereas native hrp showed only a small effect. the luminescence observed upon incubation of pholasin with native mpo was diminished by preincubation with catalase. considering the high instabil ... | 2000 | 10927181 |
| assay of dna photolyase activity in spinach leaves in relation to cell compartmentation-evidence for lack of dna photolyase in chloroplasts. | spinach cyclobutane pyrimidine dimer (cpd)-specific dna photolyase was successfully detected in leaf extracts by an assay system for plant photolyase using an improved enzyme-linked immunosorbent assay (elisa) which was newly introduced by novel horseradish peroxidase (hrp)-linked cpd specific monoclonal antibodies. the assay system includes two main steps: a photorepair reaction of cpd introduced in substrate dna and measurement of cpd remained after the photorepair by the improved elisa. when ... | 2000 | 10923805 |
| polyunsaturated fatty acids reduce non-receptor-mediated transcellular permeation of protein across a model of intestinal epithelium in vitro. | dietary polyunsaturated fatty acids influence the natural history of intestinal inflammatory diseases. varying the types of long-chain fatty acids that are exposed to cells alters the physicochemical properties of cell membranes. this study aimed to determine whether such variations alter transcellular and paracellular permeability in intestinal epithelium. | 2000 | 10921416 |
| role of molecular oxygen in the generation of hydroxyl and superoxide anion radicals during enzymatic cr(vi) reduction and its implication to cr(vi)-induced carcinogenesis. | electron spin resonance (esr) spin trapping measurements provide evidence for the generation of hydroxyl radicals (*oh) in the reduction of cr(vi) by glutathione reductase (gssg-r) in the presence of nadph as a cofactor. catalase inhibited the *oh generation, while the addition of h2o2 enhanced it, indicating that the *oh radical generation involves a fenton-like reaction. the metal chelator, deferoxamine, inhibited the *oh generation with a concomitant generation of a deferoxamine nitroxide rad ... | 2000 | 10905508 |
| electron transfer from diamond electrodes to heme peptide and peroxidase. | direct electron transfer from boron-doped diamond electrodes to heme undecapeptide and horseradish peroxidase (hrp) was examined and evaluated for the application to h2o2 biosensors. as-grown and oxygen plasma-treated diamond electrodes on which heme peptide is adsorbed exhibited cathodic current responses to h2o2 on the basis of the direct electron transfer. in a comparative study of carbon electrodes on which heme peptide was adsorbed, an oxygen plasma-treated diamond electrode exhibited respo ... | 2000 | 10905328 |
| discrete analysis of plasma oxalate with alkylamine glass bound sorghum oxalate oxidase and horseradish peroxidase. | we have reported a simple method of determination of plasma oxalate using a cl(-) and no(3)(-) insensitive oxalate oxidase purified from grain sorghum leaf and commercially available peroxidase from horseradish [pundir et al., ind. j. biochem. biophys., 35 (1998) 120-122]. the present report describes the immobilization of both the enzymes onto alkylamine glass, their kinetic properties and application for discrete analysis of plasma oxalate. in the analytic method, h(2)o(2) generated from plasm ... | 2000 | 10889278 |
| plastic changes and nitric oxide synthase induction in neurons which innervate the regenerated tail of the lizard gekko gecko. ii. the response of dorsal root ganglion cells to tail amputation and regeneration. | the lizard tail regenerates after amputation, which severs the spinal cord and spinal nerves. dorsal root ganglia (drgs) do not regenerate in the regrowing tail, which is innervated by drgs rostral to the amputation. with nissl staining, nadph-diaphorase histochemistry and nitric oxide synthase (nos) immunohistochemistry, we investigated nos expression and its relationship with structural changes in drg neurons of caudotomized lizards. first, by horseradish peroxidase retrograde tracing we here ... | 2000 | 10882786 |
| olfactory bulb and retrobulbar regions in the hedgehog tenrec: organization and interconnections. | the madagascan lesser hedgehog tenrec (echinops telfairi) is a terrestrial, nocturnal insectivore with a low encephalization index and a huge olfactory bulb. to gain insight into the organization and evolution of olfactory regions in placental mammals, the cytoarchitecture (nissl), neurochemical attributes [zinc and acetylcholinesterase stain, nicotinamide adenine dinucleotide phosphate (nadph)-diaphorase, and calcium-binding proteins], and interconnections (injections of wheat germ agglutinin-h ... | 2000 | 10880997 |
| memory landscapes of single-enzyme molecules. | immobilized single horseradish peroxidase enzymes were observed by confocal fluorescence spectroscopy during catalysis of the oxidation reaction of the nonfluorescent dihydrorhodamine 6g substrate into the highly fluorescent product rhodamine 6g. by extracting only the non-markovian behavior of the spectroscopic two-state process of enzyme-product complex formation and release, memory landscapes were generated for single-enzyme molecules. the memory landscapes can be used to discriminate between ... | 2000 | 10880561 |
| a new assay for thyroglobulin concentration in serum using monoclonal antibodies against synthetic peptides. | the concentration of thyroglobulin (tg) measured by radioimmunoassay (ria) or enzyme-linked immunosorbent assay (elisa) is greatly affected by the presence of anti-tg autoantibodies in sera. we developed a new assay for detecting tg in the presence of high concentrations of anti-tg autoantibodies. a 48-kda fragment was purified from tg after treatment with v8 protease. this fragment did not appear to bind to two types of monoclonal antibodies (57ab and 28d3) against a peptide in the c-terminus ( ... | 2000 | 10876005 |
| a sensitive immunoassay for flunitrazepam and metabolites. | the objective of this study was to develop an immunoassay that would be capable of detecting flunitrazepam and/or cross-reacting metabolites in urine and comparing the results with those obtained by gas chromatography-mass spectrometry. doses of rohypnol varying between 0.5 and 4 mg were given to volunteers, and urine was collected for up to two weeks postingestion. these samples were analyzed by an elisa that was developed using an antibody raised to flunitrazepam and a drug-enzyme conjugate pr ... | 2013 | 10872578 |
| comparative studies of the chemiluminescent horseradish peroxidase-catalysed peroxidation of acridan (gz-11) and luminol reactions: effect of ph and scavengers of reactive oxygen species on the light intensity of these systems. | in this study, the chemiluminescent horseradish peroxidase/h(2)o(2)-catalysed oxidation of acridan (gz-11) substrate was compared with the well-characterized light-producing luminol reaction. p-iodophenol and p-phenylphenol were used as enhancers, respectively, for the luminol and acridan reactions. these two light-producing systems showed significant differences in relation to the effect of ph, as well as the effect of scavengers of reactive oxygen species, on the light intensity. light product ... | 2013 | 10862148 |
| effect of aqueous extract of cigarette smoke on peripheral blood polymorphonuclear leukocytes chemiluminescence. | cigarette smoke induces a vast cohort of deleterious effects on biological structures. in the present paper, the effect of aqueous extract of cigarette smoke on the activity of polymorphonuclear leukocytes was studied. although the aqueous extract of cigarette smoke inhibits the luminol oxidation catalysed by horseradish peroxidase, it strongly interacts with polymorphonuclear leukocytes and inhibits their phorbol-induced chemiluminescence in the presence of either luminol or lucigenin. the resu ... | 2014 | 10862145 |
| determination of hydrogen peroxide by micro-flow injection-chemiluminescence using a coupled flow cell reactor chemiluminometer. | a novel flow cell reactor was developed for micro-flow injection determination of hydrogen peroxide (h(2)o(2)) using horseradish peroxide (hrp)-catalysed luminol chemiluminescence. the newly developed flow cell reactor for a chemiluminometer allowed mixing of the chemiluminescent reagents in front of a photomultiplier for maximum detection of the emitted light. the rapid mixing allowed a decrease in the flow rate of the pump to 0.1-0.01 ml/min, resulting in increased sensitivity of detection of ... | 2013 | 10862141 |
| a flow injection chemiluminescence method using cr(iii) as a catalyst for determining hydrogen peroxide. application to h(2)o(2) determination in cultures of microalgae. | flow injection analysis has been applied to the determination of hydrogen peroxide produced by some different species of microalgae. the method is based on the luminol-h(2)o(2) chemiluminescence reaction using cr(iii) as a catalyst. optimum experimental conditions for the method have been studied and trace amounts of hydrogen peroxide determined with detection limits of 4 10(-8) mol/l. the method using cr(iii) was compared with that using horseradish peroxidase as the catalyst. | 2013 | 10862140 |
| gaba and glutamate-like immunoreactivity at synapses on depressor motorneurones of the leg of the crayfish, procambarus clarkii. | to investigate their synaptic relationships, depressor motorneurones of the crayfish leg were impaled with microelectrodes, intracellularly injected with horseradish peroxidase, and prepared for electron microscopy. post-embedding immunogold labelling with antibodies against gamma-aminobutyric acid (gaba) or glutamate was carried out either alone or together on the same section and allowed the identification of three classes of input synapses: 51% were immunoreactive for glutamate and contained ... | 2000 | 10861523 |