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PubMed2005

Further field evaluation of synthetic herbivore-induced plant volatiles as attractants for beneficial insects.

Fifteen synthetic herbivore-induced plant volatiles (HIPVs) were field-tested for attractivity to beneficial insects in two experiments conducted in an open field and a hop yard in Washington State. Eleven insect species or families showed significant attraction to 13 HIPVs. The ladybeetle, Stethorus punctum picipes, was attracted to sticky traps baited with methyl salicylate (MeSA), cis-3-hexen-1-ol (He), and benzaldehyde (Be). The minute pirate bug, Orius tristicolor, was attracted to traps baited with MeSA, He, Be, and octyl aldehyde (Oa), and the bigeyed bug, Geocoris pallens, responded to MeSA, indole, and trans-2-hexen-1-al. The mymarid wasp, Anagrus daanei, was attracted to He, Oa, and farnesene. The chloropid fly, Thaumatomyia glabra, was highly attracted to methyl anthranilate. Insect families responding to HIPVs included Syrphidae (MeSA, He), Braconidae ((Z)-3-hexenyl acetate, He, cis-jasmone (J), methyl jasmonate (MeJA), methyl anthranilate (MeA)), Empididae (MeSA), Sarcophagidae (MeSA, Be, J, nonanal and geraniol), Tachinidae (Be), and Agromyzidae (MeSA). Micro-Hymenoptera (primarily parasitic wasp families) were attracted to MeSA, He, and indole. These results are discussed with respect to known properties and bioactivity of the tested HIPVs and to their potential as tools for recruiting natural enemies into agroecosystems.

Animals↗
PubMed2005

Floral odor variation in two heterostylous species of Primula.

Floral traits such as odor, color, and morphology are important pollinator attractants. Variation in floral traits may influence floral constancy, the tendency of pollinating insects to visit flowers of only one type. We investigated for the first time variation in odor between floral morphs in heterostylous species. We analyzed inter- and intraspecific odor variation in the "pin" and "thrum" floral morphs of sympatric Primula elatior and P. farinosa (Primulaceae). Floral volatiles were sampled with headspace sorption. Quantitative analysis and chemical identification were performed by gas chromatography coupled to mass spectrometry. The species produced different floral bouquets. P. elatior emitted mostly limonene with small amounts of alpha-pinene, myrcene, and sabinene. P. farinosa produced benzaldehyde, 4-oxoisophorone (2,6,6-trimethyl-2-cyclohexene-1,4-dione), benzyl alcohol, and benzyl acetate. These interspecific differences may play a role in promoting floral constancy and maintaining species integrity. Conversely, no differences were detected between the scents of pin and thrum morphs within each species. Heterostyly relies on pollinators visiting both floral morphs. There may be stabilizing selection against divergences in traits that may cause pollinators to develop floral constancy to only one of the floral morphs.

Animals↗
PubMed2005

Methyl salicylate, a soybean aphid-induced plant volatile attractive to the predator Coccinella septempunctata.

Induced volatiles provide a signal to foraging predatory insects about the location of their prey. In Iowa, early in the growing season of soybean, Glycine max, many predacious seven-spotted lady beetles, Coccinella septempunctata, were observed on plants with heavy infestations of soybean aphid, Aphis glycines. We studied whether the attraction of this beetle is caused by the release of specific volatile compounds of soybean plants infested by aphids. Volatile compounds emitted by soybean plants infested by aphids were compared with those of undamaged, uninfested, and artificially damaged plants. Gas chromatography-mass spectrometry analyses revealed consistent differences in the profiles of volatile compounds between aphid-infested soybean plants and undamaged ones. Significantly more methyl salicylate was released from infested plants at both the V1 and V2 plant growth stages. However, release patterns of two other induced plant volatiles, (D)-limonene and (E,E)-alpha-farnesene, differed between the two plant growth stages. Gas chromatographic-electroantennographic detection of volatile extracts from infested soybean plants showed that methyl salicylate elicited significant electrophysiological responses in C. septempunctata. In field tests, traps baited with methyl salicylate were highly attractive to adult C. septempunctata, whereas 2-phenylethanol was most attractive to the lacewing Chrysoperla carnea and syrphid flies. Another common lady beetle, the multicolored Asian lady beetle, Harmonia axyridis, showed no preference for the compounds. These results indicate that C. septempunctata may use methyl salicylate as the olfactory cue for prey location. We also tested the attractiveness of some selected soybean volatiles to alate soybean aphids in the field, and results showed that traps baited with benzaldehyde caught significantly higher numbers of aphids.

Animals↗
PubMed2006

Volatile emissions from Aesculus hippocastanum induced by mining of larval stages of Cameraria ohridella influence oviposition by conspecific females.

Larval stages of the horse chestnut leafminer Cameraria ohridella can completely destroy the surface of horse chestnut leaves, Aesculus hippocastanum. This study investigated the effect of the degree of leaf browning caused by the insect's larvae on olfactory detection, aggregation, and oviposition of C. ohridella adults. The influence of A. hippocastanum flower scent on oviposition of the first generation was also evaluated. Utilizing gas chromatography coupled with parallel detection by mass spectrometry and electroantennography (GC-MS/EAD), more than 30 compounds eliciting responses from antennae of C. ohridella were detected. Oviposition and mining by C. ohridella caused significant changes in the profile of leaf volatiles of A. hippocastanum. After oviposition and subsequent mining by early larval stages (L1-L3), substances such as benzaldehyde, 1,8-cineole, benzyl alcohol, 2-phenylethanol, methyl salicylate, (E)-beta-caryophyllene, and (E,E)-alpha-farnesene were emitted in addition to the compounds emitted by uninfested leaves. Insects were able to detect these compounds. The emitted amount of these substances increased with progressive larval development. During late larval stages (L4, L5) and severe loss of green leaf area, (E,E)-2,4-hexadienal, (E/Z)-linalool oxide (furanoid), nonanal, and decanal were also released by leaves. These alterations of the profile of volatiles caused modifications in aggregation of C. ohridella on leaves. In choice tests, leaves in early infestation stages showed no significant effect on aggregation, whereas insects avoided leaves in late infestation stages. Further choice tests with leaves treated with single compounds led to the identification of substances mediating an increase or decrease in oviposition.

Aesculus↗
PubMed1985

Guinea pig liver aldehyde oxidase as a sulfoxide reductase: its purification and characterization.

Guinea pig aldehyde oxidase was purified about 120-fold at a yield of 26% from liver cytosol by sequential column chromatography using DEAE-cellulose, FMN-Sepharose 4B, and Sephacryl S-300. The purified enzyme showed many similarities with the rabbit liver aldehyde oxidase reported by other workers with respect to its absolute spectra, molecular weight, and cofactor compositions of molybdenum, FAD, and nonheme iron. This enzyme efficiently utilized 2-hydroxypyrimidine and benzaldehyde as electron donors while N1-methylnicotinamide was 40 times less effective than 2-hydroxypyrimidine. Diphenyl sulfoxide was reduced anaerobically to diphenyl sulfide in the presence of electron donors. This activity was highly susceptible to SKF 525-A as well as the known inhibitors for aldehyde oxidase such as menadione, estradiol, and potassium cyanide. This enzyme also reduced dibenzyl sulfoxide, phenothiazine sulfoxide, D-biotin methyl ester d-sulfoxide, and quinoline N-oxide, but not L-methionine sulfoxide, dimethyl sulfoxide, D-biotin methyl ester l-sulfoxide, and D-biotin d- and l-sulfoxides, as well as diphenyl sulfone. These results indicate that aldehyde oxidase in guinea pig liver functions as a sulfoxide reductase with selective substrate specificity under anaerobic conditions.

Aldehyde Oxidase↗
PubMed1986

Characterization of the reduction of 3-acetylpyridine adenine dinucleotide phosphate by benzyl alcohol catalyzed by aldose reductase.

Aldose reductase from rat lens catalyzes reduction of the 3-acetylpyridine analog of NADP+ by benzyl alcohol; the fluorescence of the reduced pyridine nucleotide produced in this reaction forms the basis of a new, more sensitive assay for this enzyme. The pH dependence and kcat/Km ratio of this enzymatic reaction are very similar with NADP+ or the analog; however, at pH 7.5, the reaction with the analog has a sevenfold greater kcat. In an NADPH-supported reduction reaction, aldose reductase exhibited similar activity toward benzaldehyde and glyceraldehyde, but benzyl alcohol was a much better substrate than physiological polyols in the analog-dependent oxidation reaction: relative kcat/Km ratios were 740 for benzyl alcohol, 2.2 for xylitol, and 1.0 for glycerol. By this assay, a new, high-affinity aldose reductase inhibitor AL-1567 showed noncompetitive inhibition with the pyridine nucleotide analog, with Ki = 2.05 X 10(-6) M, and competitive inhibition with benzyl alcohol, with Ki = 5.7 X 10(-9) M, indicating that the inhibitor binds the free enzyme with extremely high affinity. Compared to spectrophotometric assays of aldose reductase activity, the fluorometric assay extends the lower limit of detectability of enzyme activity by a factor of 100, and allows the determination of Ki values for potent inhibitors of the enzyme with greater accuracy.

Alcohols↗
PubMed1986

Role of molecular oxygen in lignin peroxidase reactions.

Homogeneous lignin peroxidase (diarylpropane oxygenase) oxidized veratryl alcohol to veratryl aldehyde under anaerobic conditions in the presence of either H2O2, m-chloroperoxybenzoic acid (mCPBA), or p-nitroperoxybenzoic acid (pNPBA). Lignin peroxidase also oxidized the 1-(3',4'-diethoxyphenyl)-1,2-dihydroxy-(4"-methoxyphenyl)-propane I under anaerobic conditions in the presence of mCPBA to yield 3,4-diethoxybenzaldehyde III and 1-(4'-methoxyphenyl)-1,2-dihydroxyethane IV. In contrast to what occurs under aerobic conditions, under anaerobic conditions no 2-hydroxy-1-(4'-methoxyphenyl)-1-oxoethane V was obtained. During the diarylpropane I cleavage under anaerobic conditions, 18O from H2(18)O was incorporated into the alpha-position of the phenylglycol IV. Lignin peroxidase also hydroxylated 1-(4'-ethoxy-3'-methoxyphenyl)propane II at the alpha-position to yield 1-(4'-ethoxy-3'-methoxyphenyl)-1-hydroxypropane VI under anaerobic conditions in the presence of mCPBA. During the phenylpropane II hydroxylation under anaerobic conditions, 18O from H2(18)O was incorporated into the alpha-position of VI. These results are rationalized according to a mechanism involving an initial one-electron oxidation of the diarylpropane I by the lignin peroxidase compound I to form a benzene pi cation radical which undergoes alpha, beta cleavage to produce a benzaldehyde and a C6C2 benzylic radical. The latter is then attacked by O2 to form a hydroperoxy radical which may decompose through a tetroxide to form the phenylglycol IV and phenylketol V. Under anaerobic conditions the C6C2 benzylic radical is probably oxidized to a carbonium ion which would be subsequently attacked by H2O to yield the phenylglycol V.

Anaerobiosis↗
PubMed1986

Isolation and characterization of multiple forms of mandelonitrile lyase from mature black cherry (Prunus serotina Ehrh.) seeds.

Five multiple forms (forms 1-5) of mandelonitrile lyase (EC 4.1.2.10) which catalyze the decomposition of mandelonitrile to benzaldehyde and hydrogen cyanide have been extensively purified from seeds of black cherry (Prunus serotina Ehrh.) by concanavalin A-Sepharose 4B chromatography and chromatofocusing. These forms are monomers which differ only slightly in molecular weight (57,000-59,000) and isoelectric point (4.58-4.63), but heterogeneity in their carbohydrate side-chains was suggested by concanavalin A-Sepharose 4B chromatography. The absorption spectra of the predominating forms 4 and 5 showed maxima of 278, 380, and 460 nm, indicative of flavoprotein character. Detailed comparative kinetic studies of forms 4 and 5 revealed few significant differences in behavior. Both proteins showed pH optima between 6.0 and 7.0, had identical Km values (0.17 mM) for (R,S)-mandelonitrile, and retained similar activities upon storage at 4 and -20 degrees C. Neither form exhibited a metal ion requirement and both were affected similarly by metal salts, beta-mercaptoethanol, and sulfhydryl reagents. Benzoic acid, p-hydroxybenzyl alcohol, and benzyl alcohol inhibited both forms.

Aldehyde-Lyases↗
PubMed1986

Purification and characterization of mandelonitrile lyase from Prunus lyonii.

The enzyme mandelonitrile lyase (EC 4.1.2.10) which catalyzes the decomposition of the cyanohydrin of benzaldehyde has been isolated and purified to homogeneity from mature seeds of the California cherry (Prunus lyonii). The purification procedure involved chromatography on DEAE-cellulose and Con-A-Sepharose with a final recovery of 60% of enzyme activity. Purification of only 4.3-fold yielded a nearly homogeneous preparation. The absorption spectrum of this protein shows maxima at 278, 389, and 463 nm, indicative of its flavoprotein character. The native molecular weight for the lyase was found to be 50,000. The subunit molecular weight of 59,000 was estimated by gel electrophoresis in the presence of sodium dodecylsulfate. The isoelectric point was estimated to be 4.75. The enzyme has a narrow pH optimum around 5.5 and is highly stable at 4 degrees C.

Aldehyde-Lyases↗
PubMed1989

Characterization of rat cornea aldehyde dehydrogenase.

Aldehyde dehydrogenase has been purified from rat cornea in a single step. The enzyme is a class 3 aldehyde dehydrogenase. Cornea aldehyde dehydrogenase is a 100-kDa dimer composed of 51-kDa subunits, prefers NADP+ as coenzyme, and preferentially oxidizes benzaldehyde-like aromatic aldehydes as well as medium chain length (4-9 carbons) aliphatic aldehydes. The substrate and coenzyme specificity, immunochemical properties, effect of disulfiram, pH profile, and isoelectric point of cornea aldehyde dehydrogenase are identical to those of tumor-associated aldehyde dehydrogenase, the prototype class 3 enzyme. The substrate and coenzyme preferences are consistent with a role for cornea aldehyde dehydrogenase in the oxidation of a variety of aldehydes generated by lipid metabolism, including lipid peroxidation.

Aldehyde Dehydrogenase↗
PubMed1990

Hemolysis of erythrocytes and fluorescence polarization changes elicited by peptide toxins, aliphatic alcohols, related glycols and benzylidene derivatives.

Hemolysis rates of human erythrocytes induced by C2 and C8-C14 straight chain 1-alkanols, 1,2-alkanediols and the corresponding benzylidene derivatives (benzaldehyde acetals) have been studied and compared with hemolysis rates obtained by three peptide toxins. The peak of activity occurs at C12 for the alkanols and glycols and at C10 for the benzylidene derivatives. The most active compound is 1-dodecanol, followed by 1,2-dodecanediol and the C10 benzylidene acetal, which show 50% hemolysis at 15, 99 and 151 microM, respectively, at 37 degrees C. A few lysolecithins and longer chain cis-unsaturated alcohols were studied for comparison purposes, and were found to be more active than 1-dodecanol. The most active were the 16:0 lysolecithin and cis-9-tetradecene-1-ol, which gave 50% hemolysis at concentrations of 2.8 and 5.6 microM respectively. The hemolytic activities of 1-dodecanol, 1,2-dodecanediol and the C10 benzylidene acetal were compared to activities of Pyrularia thionin and melittin with cow, horse, sheep, pig and human erythrocytes. Whereas the peptide toxins showed clear specificity for human erythrocytes, no selectivity was shown by any of the other compounds tested. Addition of the thionin or Naja naja kaouthia cardiotoxin to erythrocyte ghosts caused a slight but reproducible increase in the order of the phospholipid bilayer, as measured with the fluorescent probe NBD-PC. Cardiotoxin gave a greater response than did the P thionin, and extensively iodinated P thionin gave a smaller change than did P thionin. Similar results were obtained with melittin, but this peptide gave a markedly greater response than all other peptides. Addition of dodecanol or the C10 benzylidene acetal caused a marked increase in membrane fluidity. All of these data indicate that the organic compounds interact directly with and are incorporated nonspecifically into the membrane lipid bilayer, but the peptide toxins interact specifically with some component on the surface of the membrane, either a protein or specific phospholipid domain, followed by insertion into the membrane and decreasing phospholipid movement.

Alcohols↗
PubMed1976

The reaction of sulfhydryl reagents with bovine hepatic monoamine oxidase. Evidence for the presence of two cysteine residues essential for activity.

The bovine liver monoamine oxidase (EC 1.4.3.4) was found to be inactivated by various well-known sulfhydryl reagents like p-mercuribenzoate, methylmercuric iodide and 5,5'-dithiobis-(2-nitro benzoic acid). The present investigation shows that the inactivation of the enzyme results from reactions of these reagents with 2 out of 8 titratable sulfhydryl groups per 10(5) g of the enzyme. The substrate, benzylamine, and competitive inhibitors like benzaldehyde, p-nitrobenzaldehyde, benzyl alcohol protected the enzyme from inactivation by the mercurials or the Ellman reagent. The inactivation experiments with these sulfhydryl reagents, the protection experiments, and the kinetics as well as physicochemical observations suggest that there are only two cysteine residues that are required for activity of the enzyme. It is possible that these two residues may be active-center residues.

Animals↗
PubMed1979

Serine hydroxymethylase. Specificity of bond cleaveage to form quinonoid intermediates and rate of holoenzyme formation.

L-Serine transhydroxymethylase (5,10-methylenetetrahydrofolate:glycine hydroxymethyltransferase, EC 2.1.2.1) a pyridoxal phosphate-dependent enzyme, has been obtained as a homogeneous preparation with a specific activity of 6.7 mumol benzaldehyde per minute at 30 degrees C at pH 7.5 in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (Hepes) buffer, with DL-threo-beta-phenylserine as a substrate. This enzyme has been used to study the specificity of bond cleavage in forming quinonoid intermediates from DL and non-asymmetric amino acids. The ability of the generated quinonoids to react with formaldehyde and acetaldehyde has also been studied and evidence obtained for formation of the corresponding beta-hydroxymethyl and beta-hydroxyethyl amino acid derivaties. Apotranshydroxymethylase has been prepared and the rate of holoenzyme formation was found to be 0.52 min-1 by measuring Schiff base formation at 425 nm and 0.66 min-1 as determined from restoration of enzymic activity. A requirement for the presence of mercaptoethanol for complete reactivation was also established by these studies.

Aldehydes↗
PubMed1991

Metabolism of oxidized linoleic acid: characterization of 13-hydroxyoctadecadienoic acid dehydrogenase activity from rat colonic tissue.

An oxidized derivative of linoleic acid, 13-hydroxyoctadecadienoic acid (13-HODE), is dehydrogenated by an NAD+ dependent dehydrogenase present in rat colon mucosa. The product of the reaction is the 2,4-dienone, 13-oxooctadecadienoic acid. Enzyme activity was determined by HPLC analysis of incubation mixtures as well as by measuring the increase in absorbance at 285 nm, which represents formation of the 2,4-dienone chromophore. Characteristics of the reaction with respect to protein concentration, time of incubation and substrate dependence were investigated. Several inhibitors of known dehydrogenases had no effect on the 13-HODE dehydrogenase. These include, ethanol, indomethacin, 6-methyl-17-hydroxyprogesterone acetate, 4-(diethylamino)-benzaldehyde, and aspirin. The enzyme was mildly inhibited by pyrazole, 4-methylpyrazole and ibuprofen. Disulfiram was found to be a potent inhibitor of enzyme activity with an IC50 of 200 microM. Inhibitor specificity, and other characteristics of the reaction suggest the enzyme is neither alcohol dehydrogenase, diol dehydrogenase, nor a prostaglandin dehydrogenase. It is possible this enzyme plays an important role in the response of the colonic mucosa to the mitogenic effect of oxidized fatty acids.

Alcohol Oxidoreductases↗
PubMed1985

Subcellular distribution and properties of a clofibrate-induced aldehyde dehydrogenase from rat liver.

The influence of hypolipidemic drug clofibrate on the activity of aldehyde dehydrogenase with different substrates was studied in subcellular fractions of rat liver homogenate. It was shown that under the action of clofibrate the content of the enzyme was increased 2-3-fold in purified peroxisomal fraction as well as in microsomes and mitochondria. No difference was found in the cytoplasmic fraction. Partial purification of clofibrate-induced aldehyde dehydrogenase from microsomes was undertaken. The enzyme is apparently membrane-bound. It has a molecular weight of 187,000 and a subunit size of 47,000, indicating that the molecule is a tetramer. An induced aldehyde dehydrogenase is active with several aliphatic and aromatic aldehydes but not with formaldehyde and glyceraldehyde. The enzyme has Km-values in the millimolar range for acetaldehyde, propionaldehyde, benzaldehyde and phenylacetaldehyde and in the micromolar range for nonanal. Both NAD and NADP serve as coenzymes for the purified aldehyde dehydrogenase. According to substrate specificity, kinetic and molecular properties clofibrate-induced aldehyde dehydrogenase appears to be identical to normal liver microsomal enzyme.

Aldehyde Dehydrogenase↗
PubMed1986

Effect of spin traps in isolated rat hepatocytes and liver microsomes.

Spin traps are increasingly employed in the detection of free radicals in biological systems, including liver microsomes and isolated hepatocytes. Two spin traps phenyl-t-butyl nitrone (PBN) and 4-pyridyl-l-oxide-t-butyl nitrone (4-POBN) have been tested for their effects on hepatocyte viability and mixed-function oxidase activity. High concentration of PBN but not of 4-POBN proved to moderately affect liver cell integrity, without interfering with intracellular ATP or cytochrome P-450 content. PBN also decreased hepatocyte GSH content, probably as the result of its metabolism to benzaldehyde. The two spin traps were found to inhibit aminopyrine demethylase and ethoxycoumarin deethylase activity in hepatocytes and microsomes. At low concentrations (1-5 mM) PBN enhanced aniline hydroxylase while high concentrations of the spin trap inhibited this activity. The inhibition of the monooxygenase system was not caused by damage of microsomal enzymes, but rather by competition with other substrates for the binding to the haemoprotein. The effects of spin traps on mixed function oxidase systems should be taken into account when evaluating the results of spin trapping experiments.

Animals↗
PubMed1989

Mutagenicity of benzyl S-haloalkyl and S-haloalkenyl sulfides in the Ames-test.

The mutagenicity of benzyl 1,2,3,4,4-pentachlorobutadienyl sulfide (BPBS) and benzyl 1,2-dichlorovinyl sulfide (BDVS) was studied in the Ames preincubation assay to investigate the hypothesis that the mutagenic effect of the cysteine S-conjugates S-(pentachlorobutadienyl)-L-cysteine and S-(1,2-dichlorovinyl)-L-cysteine is associated with their metabolism to unstable thiols. Under conditions enabling cytochrome P-450-dependent benzylic hydroxylation of BPBS and BDVS, both benzyl sulfides were mutagenic. These results in combination with the lack of mutagenicity observed with benzaldehyde and with the tert-butyl analogues, which cannot be metabolized to a hemimercaptal, indicate that the formation of unstable thiols is responsible for the mutagenic effects of the benzyl sulfides and the corresponding cysteine S-conjugates. Benzyl 2-chloro-1,1,2-trifluoroethyl sulfide, which also undergoes benzylic hydroxylation, was negative in the Ames-Test; this is in agreement with the observed lack of mutagenicity of the corresponding S-conjugate S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine. Also, benzyl 2-chloroethyl sulfide, which, along with the corresponding S-conjugate S-(2-chloroethyl)-L-cysteine, does not require bioactivation, was a potent, direct-acting mutagen in the Ames-Test.

Animals↗
PubMed1991

Xenobiotic-metabolizing enzymes in human respiratory nasal mucosa.

Study of oxidative and non-oxidative xenobiotic-metabolizing enzymes was undertaken in microsomal and cytosolic fractions of two human livers, 10 individual and several pooled samples of human respiratory nasal mucosa obtained by surgical operation of male and female patients affected by hypertrophy of the inferior turbinates. The purity of nasal microsomes was checked by electron microscopy and marker enzyme assay. The pooled samples of respiratory nasal epithelium contained, relative to liver, a low amount of cytochrome P450 (about 25 pmol/mg protein) and associated biotransformation activities, and a low level of other components of the mixed-function oxidase system such as cytochrome b5, NADH and NADPH-cytochrome c reductase however the NADH-cytochrome b5 reductase activity was comparable to that of liver. The P450-dependent monooxygenase activities such as ethoxycoumarin O-deethylase, ethoxyresorufin O-deethylase and the dimethylnitrosamine N-demethylase were found in nearly all nasal microsomal specimens. The aniline hydroxylase and the aminopyrine or hexamethylphosphoramide N-demethylases were detected only in the pooled nasal samples. With regard to the non-oxidative enzymes, the activities of glutathione S-transferase, DT-diaphorase, epoxide hydrolase, UDP-glucuronyl-transferase, carbonyl reductase, benzaldehyde and propionaldehyde dehydrogenases, were investigated both in the individual and pooled nasal tissues and livers. These activities were similar in nasal and liver tissue, except for UDP-glucuronyltransferase which was not detected in nasal mucosa. The present findings demonstrate that the respiratory section of human nose contains a wide array of oxidative and non-oxidative enzymes, which could play a crucial role in the bioactivation or detoxication in situ of inhaled xenobiotics.

Adolescent↗