CHEMILUMINESCENCE FROM THE OXIDATION OF AUXIN DERIVATIVES

Abstract— The thiophenyl ester of indole-3-acetic acid and indole-3-acetonitrile produce chemiluminescence in aerated dimethylsulfoxide in the presence of potassium t -butoxide. The emitter is the aromatic aldehyde. In the case of acetonitrile, the other product expected from the cleavage of an intermediate dioxetane, cyanate/isocyanate, has also been identified. Other auxins also chemiluminesce under similar conditions, but the emitters have not been properly identified.
These systems are models for the peroxidase catalyzed oxidation of indole-3-acetic acid to indole-3-carboxaldehyde and as such support the earlier inference (Vidigal et al , 1975) that the excited aldehyde is generated in the enzymic process.
An additional result is the observation of an exciplex between excited indole-3-carboxaldehyde and the thiophenylester of indole-3-acetic acid. This appears to be the first case of chemical generation of an exciplex by a route other than radical ion reaction, presumably by the dioxetane route.     

SPECTRAL CHARACTERISTICS OF THE EXCITED STATES OF THE PRODUCT OF THE CHEMILUMINESCENCE OF LUMINOL*

Abstract— In dimethylsulfoxide the emission spectrum of luminol chemiluminescence is red-shifted by 300 cm^-1 from the photoexcited fluorescence of the product 3-aminophthalate dianion, while in aqueous solvent the two spectra are identical. The spectral properties of the product dianion have been measured in aqueous solvent and in a number of aprotic solvents, both at room temperature and at 77°K. The ground states and the excited states from which emissions are observed are characterized. Two alternatives are presented to explain the aprotic emission spectra.     

SPECTRAL CHARACTERISTICS AND MECHANISM OF CHEMILUMINESCENCE FROM TRYPTOPHAN SOLUTIONS INDUCED BY UV-IRRADIATION

The spectral distribution of the chemiluminescence, fluorescence and phosphorescence of tryptophan aqueous solutions irradiated with high and low pressure mercury lamps has been measured. The blue emission bands in the region of 380–520 nm observed both in the chemi- and photoluminescence, as well as an absorbance increase at 230 and 330 nm, indicate oxidative degradation of tryptophan leading to the formation of derivatives of N-formylkynurenine, xanthurenic and anthranilic acids. Red emission bands at 630 and 705 nm in the spectrum of the chemiluminescence, an enhancement of light intensity by D₂O and its decrease by NaN₃ and DABCO suggest a partial contribution of O₂(¹Δ_g) to the photooxidation and chemiluminescence of tryptophan. The enthalpy of the exergonic reactions, leading to the formation of luminescing products, was calculated to average -270 kJ-mol.     

CHEMILUMINESCENCE FROM AUTOXIDIZING 6-HYDROXYDOPAMINE: THE INVOLVEMENT OF ACTIVATED FORMS OF OXYGEN

Abstract— The autoxidation of the catecholamine neurotoxin 6-hydroxydopamine (20 μ M ) gave rise to a chemiluminescence which was greatly stimulated by FeSO₄ (20 μ M ) or by hydrogen peroxide addition (20 μ M to 2 m M ). The luminescence of both 6-hydroxydopamine alone or 6-hydroxydopamine plus hydrogen peroxide was strongly inhibited by catalase and by superoxide dismutase (both at 10 μg/m/); bovine serum albumin at 10 μg/m/ had no inhibitory effect. The luminescence was also strongly inhibited by several potent hydroxyl radical trapping agents and also by low concentrations of the ¹O₂ quencher DABCO (l,4-diazabicyclo-2.2.2.-octane). Chemiluminescence was greatly enhanced in D₂O, a solvent in which ¹O₂ has a prolonged lifetime. These data demonstrate the involvement of hydrogen peroxide, the superoxide radical and the hydroxyl radical in the chemiluminescence. The data are also consistent with some role for ¹O₂.     

CORRELATION OF UVC AND UVB CYTOTOXICITY WITH THE INDUCTION OF SPECIFIC PHOTOPRODUCTS IN T-LYMPHOCYTES AND FIBROBLASTS FROM NORMAL HUMAN DONORS

Abstract— By using specific monoclonal antibodies in situ and a computer-assisted image analysis system we have determined the relative induction of cyclobutane dimers, (6–4) photoproducts and Dewar isomers in human mononuclear cells and fibroblasts following irradiation with UVC, broad-spectrum UVB and narrow-spectrum UVB. The lamps produced these lesions in different proportions, with broad-spectrum UVB inducing a greater combined yield of (6–4) photoproducts and Dewar isomers per cyclobutane dimer than UVC or narrow-spectrum UVB. The relative induction ratios of (6–4) photoproducts compared to cyclobutane dimers were 0.15, 0.21 and 0.10 following irradiation with UVC, broad- or narrow-spectrum UVB, respectively. Although Dewar isomers were induced by UVC, their relative rate of formation compared to cyclobutane dimers was significantly greater after irradiation with either broad-spectrum or narrow-spectrum UVB. These values were 0.001, 0.07 and 0.07, respectively. With each lamp source, we have determined the survival of normal human T-lymphocytes and fibroblasts at fiuences, which induce equivalent yields of cyclobutane dimers, (6–4) photoproducts or (6–4) photoproducts plus Dewar isomers. Killing of fibroblasts appears to be associated with (6–4) photoproduct formation, whereas killing of T-lymphocytes seems to be mediated by combined (6–4) plus Dewar yields. These results emphasize the need to study the biological effects of UVB because cellular responses may be different from those following UVC irradiation.     

HYDROGEN PEROXIDE-DEPENDENT GENERATION OF SINGLET MOLECULAR OXYGEN BY HUMAN SALIVA: ITS DETECTION BY CHEMILUMINESCENCE FROM A Cypridina LUCIFERIN ANALOG

By the addition of hydrogen peroxide to human saliva, chemiluminescence from Cypridina luciferin analog (CCLA) and oxygen evolution were observed. Chemiluminescence was inhibited by inhibitors of salivary peroxidase, azide and cyanide and by a singlet oxygen quencher, crocin. Deuterium oxide (99.75%) stimulated the initial increase of CCLA by15–50% and the integrated CCLA 2.1-3.6-fold. The result suggest that the generation of singlet oxygen by peroxidase in human saliva depends on hydrogen peroxide.     

THE QUANTUM YIELD OF THE CHEMILUMINESCENCE OF DIMETHYLBIACRIDYLIUM NITRATE AND THE MECHANISM OF ITS ENZYMICALLY INDUCED CHEMILUMINESCENCE*

Abstract— Quantum yields for dimethylbiacridylium ion chemiluminescence based on the amount of methyl acridone formed by treatment with either H₂O₂ or with xanthine oxidasehypoxanthine in 0.01 M Na₂CO₃ at pH 10.4 and at 25°C were found to lie between 0.011 and 0.020 with an average of about 0.016.In mixed solvents containing pyridine and water or alcohol and water the emission spectrum of chemiluminescence of dimethylbiacridylium ions as well as those of diniethylbiacridene and its oxide were found to be identical with or very similar to the fluorescence of methyl acridone in the same solvent.A mechanism involving two successive two equivalent reductions of the diniethylbiacridylium ion to dimethylbiacridan followed by a radical attack and auto-oxidation leading to a compound which can undergo a reverse aldol type reaction to yield one (or two) molecule of methylacridone and one of a somewhat more reduced form is suggested.The kinetic equation relating maximum intensity of chemiluminescence to dimethylbiacridylium ion, hypoxanthine, xanthine oxidase, H⁺ and O₂ concentrations was derived from the scheme suggested and found to fit satisfactorily the data obtained from a series of experiments in which the quantum yield was also obtained.     

LONG WAVELENGTH UV RADIATION AFFECTS CHEMILUMINESCENCE OF HUMAN POLYMORPHONUCLEAR LEUCOCYTES

Abstract— Luminol-enhanced chemiluminescence in suspensions of human polymorphonuclear leucocytes stimulated with the chemotactic oligopeptide formyl-methionyl-leucyl-phenylalanine was increased by exposure of the cells to long wavelength UV radiation (mainly320–400 nm). Leucocytes treated with 0.3 × 10⁴ J m^-2 of UV responded with doubled peak values, and 4 × 10⁴ J m^-2 lead to a five-fold increase in peak chemiluminescence, as compared with non-exposed cells. Supernatants isolated from irradiated leucocytes contained increased amounts of both myeloperoxidase and lactate dehydrogenase and showed higher chemiluminescence values, when compared with supernatants from sham-irradiated cells. The results suggest that leucocyte degranulation contributes to the inflammatory properties of long wavelength UV.     

气相色谱法测定人体血液中乙醇含量的测量不确定度评定

对气相色谱法测定人体血液中乙醇含量的测量不确定度进行评定。人体血液中乙醇含量测量结果的测量不确定度主要来源于相对定量校正因子、检材量、检材中添加内标物叔丁醇的体积、检材中乙醇峰面积的平均值与添加内标物叔丁醇峰面积的平均值之比、无水乙醇的纯度及密度等参数引起的不确定度。当检材中乙醇的含量为0．915mg／mL时,扩展不确定度为O．030mg/mL(k=2)。     

EFFECT OF SIMULATED WEIGHTLESSNESS ON THE RESPONSE CHARACTERISTICS OF HUMAN BRAIN

In order to systematically investigate the effects of simulated weightlessness on thefunction state of human brain, 15° head-down tilt (HDT) was used to simulate weightless-ness, and the response changes of event-related EEG power spectra, medium-frequencysynchronous potentials and slow-waves were examined in the present study. It was foundthat HDT had characteristic effects on the above EEG responses, suggesting that the ef-fects mainly occurred in the brain's regulatory system, therefore, resulting in changes ofthe brain function state.     

THE CHEMILUMINESCENCE OF CERTAIN INDOLES*

Abstract— A series of twenty-four indoles and related compounds have been examined for chemiluminescent activity in aqueous solution and in dimethylsulfoxide. Seven compounds were found to chemiluminesce in the presence of base and peroxydisulfate in aqueous solution and eleven compounds gave chemiluminescence in dimethylsulfoxide with base using oxygen as the oxidizing agent. The relative intensities have been determined. There is no clear correlation between substitution patterns and the presence of chemiluminescence in either series. Some preliminary kinetic studies have been made on the indole system. Product studies indicate that the indole is degraded by at least two different pathways and that chemiluminescent process is probably only a small fraction of the total chemical change occurring.     

QUENCHING OF SINGLET OXYGEN BY HUMAN PLASMA

Direct measurements of the decay of singlet oxygen phosphorescence at 1270 nm were made in human plasma diluted with various amounts of deuterium oxide. The Stern-Volmer plot of the singlet oxygen lifetimes was linear up to 15% plasma concentration (vol/vol). Extrapolation of these measurements to 100% plasma content gave a singlet oxygen lifetime of 1.04 +/- 0.03 microseconds in human plasma. Biological molecules accounted for 77% of the total singlet oxygen quenching while water accounted for 23% of the quenching. The contributions of various types of biological molecules to the total singlet oxygen quenching were calculated from their plasma concentrations and their quenching constants. Plasma proteins quenched most of the singlet oxygen. Uric acid also quenched a significant amount of singlet oxygen (12%). Tocopherols, carotenoids, ascorbic acid and bilirubin made only small contributions to the total singlet oxygen quenching (less than or equal to 4%).     

RED CHEMILUMINESCENCE FROM RAM SEMINAL VESICLE MICROSOMES: PITFALLS IN THE USE OF SPECTRALLY RESOLVED RED CHEMILUMINESCENCE AS A TEST FOR SINGLET OXYGEN IN BIOLOGICAL SYSTEMS

Abstract— The assignment of the red chemiluminescence bands in the ram seminal microsome system to singlet oxygen as previously reported by Cadenas and Sies (1983) Hoppe-Seyler's Z. Physiol. Chem. 364, 519-528 was re-evaluated. Measurements of 1268 nm emission demonstrated that ram seminal vesicle microsomes produced very small quantities of singlet oxygen (0.41 2 0.05 p.M) when they metabolized high concentrations of 15-hydroperoxyarachidonic acid (1 mM). The red chemilumi- nescence, however, was not due to singlet oxygen, since it failed to increase in deuterium oxide and it was five orders of magnitude larger than the predicted emission from singlet oxygen produced in this system. Quantitative measurements of the time integral of the square root of the red chemiluminescence intensity may be a useful test to confirm the assignment of red emission to singlet oxygen in other biochemical systems.     

THE 75°C THERMOLUMINESCENCE BAND OF GREEN TISSUES: CHEMILUMINESCENCE FROM MEMBRANE-CHLOROPHYLL INTERACTION

Abstract— Exposure of thylakoid membranes of green plants to high temperature promotes the appearance of free radicals resulting in a thermoluminesccnce (TL) band peaking around 75°C. The occurrence of this band with the same intensity in prcilluminated and in dark-adapted samples demonstrates that, contrary to several other TL bands, it is not a result of charge recombination. The high temperature TL band is oxygen dependent. Parallel to TL emission singlet oxygen is formed, as demonstrated by spin trapping EPR measurements and by the decrease of TL intensity in the presencc of sodium-azide, a singlet oxygen scavenger.
We suggest that the 75°C TL band is a result of a temperature-enhanced interaction between molecular oxygen and the photosynthetic membrane, possibly involving lipid peroxidation. The spectral maximum of the emission (around 720 nm) implics that light emission occurs upon energy transfer from an excited product to chlorophyll molecules destablized from pigment-protein complexes.     

鲁米诺-过硫酸钠-卡托普利化学发光体系的研究

基于卡托普利对过硫酸钠鲁米诺化学发光体系的强烈抑制作用,建立起一种直接测定卡托普利的流动注射化学发光新方法。该方法灵敏、简单、快速。线性范围为5.0×10-5～1.0×10-3g·L-1,检出限为1.7×10-5g·L-1,相对标准偏差为3.2%。利用该方法对卡托普利片剂含量的测定,结果满意。     

CHEMILUMINESCENCE IN THE PEROXIDATION OF TANNIC ACID

Abstract— Peroxidation of tannins with alkaline H₂O₂ is accompanied by weak chemiluminescence in the spectral region 480–800 nm. o-Di and tri-hydroxy groups of polyphenols undergo oxidation by a free-radical mechanism and a green intermediate anion-radical with absorption Δ_max= 600 nm is formed. The radical mechanism is supported by the low activation energy 14–20 kJ/mol and the quenching effect of radical scavengers. The reaction of the green intermediate with peroxy anions is the chemiluminescence rate limiting step. In the presence of a-hydroxy-methylperoxide formed from H₂O₂ and formaldehyde, the alkaline peroxidation of tannins is accompanied by strong red luminescence (420–800 nm). The base catalyzed decomposition of peroxides gives only a weak red emission (460–800 nm). Light intensity is enhanced in D₂O by a factor 6.5. Quenchers of O₂(¹Δ_g) and 1,3-di-phenylisobenzofurane diminish light intensity in non-aqueous solutions. The data suggest ¹O₂ participation in the observed chemiluminescence. Thermo-chemical calculations give —ΔH values from 250–1000 kJ/mol for one elementary reaction step which limits the mechanism of chemi-enereization. Chemiexcitation of tannins is relevant to biochemical mechanisms of aerobic degradation of aromatic compounds, energy utilization as well as to defense and resistance processes in plants.     

THE RATE OF REMOVAL OF SUNLIGHT-INDUCED PYRIMIDINE DIMERS FROM THE DNA OF CULTURED HUMAN DIPLOID FIBROBLASTS

Abstract The rate of excision of sunlight-induced pyrimidine dimers in DNA of exposed human cells was determined. Two normal excision repair-proficient human diploid fibroblast strains (WS-1 and KD) and a repair-deficient strain (XP12BE, group A) maintained in a nondividing state were exposed to summer noon-time sunlight for times (5 and 20 min) that induced numbers of dimers equivalent to far UV (254 nm) exposures of 1 and 4 J/m². Pyrimidine dimers were quantified in extracted DNA using a U V-endonuclease-alkaline sedimentation assay. The excision rates of these dimers were similar to those observed for the excision of UV-induced pyrimidine dimers. No sunlight-induced inhibition or stimulation of DNA repair was observed in either strain at these low exposures.     

CELLULAR DELIVERY AND RETENTION OF PHOTOFRIN II: THE EFFECTS OF INTERACTION WITH HUMAN PLASMA PROTEINS

The absorbance and fluorescence spectra of Photofrin II (PII) in the presence of albumin, globulins and lipoproteins from human plasma show that all of these proteins induce a degree of disaggregation of PII material. In addition, there are substantial rearrangements in the distribution of different fractions contained in PII and their binding to the protein. It is shown that these rearrangements have considerable impact on the uptake of PII by cultured cells and the ensuing retention of the drug in the cells. The information on the contribution of fluorescing and non-fluorescing components of PII in the cells was obtained by measuring first the PII fluorescence in suspensions of live cells, followed by chemical extraction of porphyrin material from the same cells. The interaction of PII with low density lipoproteins resulted in markedly lower levels of PII material retained in the cells, compared to protein-free drug exposure. Somewhat better but still inferior PII retention was observed with high density lipoproteins. The samples with very low density lipoproteins showed increased uptake of PII, but the subsequent retention of the drug was low, so that the remaining amount of the drug was not much different than in protein-free samples. The strongest inhibition of PII uptake was seen with albumin, with ensuing retention of PII not significantly different than in protein-free samples. The best retention of PII was observed with globulins, with approx. 25% higher total drug content retained in the cells after long-term clearance relative to protein-free samples.