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PubMed2002

Attractant volatiles released by female and male Triatoma infestans (Hemiptera: Reduviidae), a vector of chagas disease: chemical analysis and behavioral bioassay.

Volatiles emitted by male and female T infestans before and during copula were collected on Porapak-Q filters, desorbed with dichloromethane, and analyzed by gas chromotography and gas chromatography-mass spectrometry after confirmation of attractiveness in an arena bioassay. Chemical analysis confirmed the presence of (R,S) -2- and 3-methylbutan-1-ol in a 2:1 ratio; short chain acids (ethanoic to nonanoic acid); long chains acids decanoic to (Z)-9-octadecenoic acid; aliphatic aldehydes (hexanal to nonanal), benzaldehyde and dipropylsulphide from insects in copula. Electroantennographic studies conducted with a homologous series of aliphatic aldehydes on female and male T infestans showed that, for a given dose, EAG responses elicited from both sexes increased with increased chain length up to nonanal, after which EAG-activity declined. Attractiveness of non-acidic trace components identified in the volatiles were tested on male and female T. infestans, in an arena bioassay using a video tracking method. Aliphatic C6 to C10 aldehydes were tested: hexanal (1-100 microg) and heptanal (10 microg) were attractive to female T. infestans, high doses of octanal and nonanal (1-100 microg) were Unattractive to male and female T. infestans but low doses of nonanal (0.01-0.1 microg) were attractive to male T infestans. Benzaldehyde was highly attractive to female T. infestans at low doses (0.05- 0.1 microg). 3-methylbutan-1-ol was attractive to male T infestans at high dose (1,000 microg). (S) or (S,R) 2-methyl-butan-1-ol were attractive to males or females (1-1,000 microg). Blends of hexanal and benzaldehyde (20:1 and 40:1) showed an additive effect on attraction compared with hexanal alone, when tested on female T. infestans. The study has demonstrated the presence of a number of electrophysiologically and behaviorally active compounds in volatiles emitted by T. infestans in copula that may have a role in the postulated copulation pheromone.

Animals↗
PubMedDate not supplied

Airborne aldehydes from heating rosin core solder and liquid rosin flux to soldering temperatures.

Gas phase aldehydes produced from heating rosin core solder and liquid rosin flux to temperatures commonly used in soldering were trapped on sampling tubes containing XAD-2 resin coated with the derivatizing agent 2-hydroxymethylpiperidine. Analysis of the resulting oxazolidine derivatives was performed using gas chromatography/mass spectrometry (GC/MS). The observed aldehyde derivatives included formaldehyde, acetaldehyde, propionaldehyde, acrolein, isobutyraldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, furfural, hexanal, cyclohexane carboxaldehyde and other unidentified compounds likely to be aldehyde isomers. Formaldehyde, acetaldehyde, and benzaldehyde were detected in blank samples. By comparison with an internal standard, a sample produced by drawing air with contaminants derived by heating rosin core solder through a sampling tube contained levels of formaldehyde and acetaldehyde much greater than seen in sampling tube blanks. Benzaldehyde was not shown to be present at a significantly greater level in samples from heating rosin core solder than in blanks prepared using the same analysis protocol. The use of National Institute of Occupational Safety and Health (NIOSH) method 2539 extraction procedures produced blanks with levels of formaldehyde significantly lower than with a modified extraction method (methylene chloride, no sonication). The modified extraction method produced significantly lower benzaldehyde levels in blanks compared with the NIOSH extraction method using toluene and sonication of sampling sorbent tubes.

Air Pollutants, Occupational↗
PubMed2002

Airborne carbonyls from motor vehicle emissions in two highway tunnels.

Carbonyls (aldehydes and ketones) continue to receive scientific and regulatory attention as toxic air contaminants, mutagens, and carcinogens. Vehicle emissions are a major source of carbonyls in outdoor air, but information about the nature and magnitude of carbonyl emissions by motor vehicles is limited. The objective of this study was to identify speciated carbonyls emitted by motor vehicles under real-world, on-road conditions and to calculate on-road carbonyl emission factors. We collected air samples at the inlet and outlet of two highway tunnels, the Caldecott Tunnel near San Francisco and the Tuscarora Mountain Tunnel in Pennsylvania. At the Caldecott Tunnel, the fleet consisted almost entirely of light-duty (LD) vehicles that used California phase 2 reformulated gasoline. Vehicle count, speed and other parameters relevant to carbonyl emissions were nearly the same from one assessment to the next. At the Tuscarora Mountain Tunnel, the fleet included LD vehicles and heavy-duty (HD) diesel trucks. This part of the study was designed to capture differences in percentage of LD and HD vehicles from one assessment to the next. Air downstream of KI oxidant scrubbers was sampled on silica gel cartridges coated with 2,4-dinitrophenylhydrazine (DNPH). Carbonyls were identified as their DNPH derivatives by liquid chromatography (LC) with detection by diode-array, UV-visible spectroscopy and by atmospheric pressure negative-ion chemical ionization mass spectrometry (MS). About 100 carbonyls were identified. For about 30 of these carbonyls, concentrations were measured at the inlet and outlet of both tunnels. This information was used to calculate on-road carbonyl emission factors for LD vehicles (Caldecott Tunnel) and for the overall fleet (Tuscarora Mountain Tunnel). At the Tuscarora Mountain Tunnel, data for the fleet were used to calculate carbonyl emission factors for LD vehicles and for HD diesel trucks, the majority of which were weight class 7-8 trucks. Carbonyl emission factors at the Caldecott Tunnel were calculated as milligrams of emissions per liter of fuel consumed. Those at the Tuscarora Mountain Tunnel were calculated as milligrams of emissions per distance traveled and then converted to milligrams per liter using the fuel economy reported by Gertler et al (2000) for this tunnel (14.75 km/L for LD vehicles and 3.15 km/L for HD vehicles). At the Caldecott Tunnel, the LD vehicles emission factor was 68.4 mg/L for total measured carbonyls; the ten most abundant carbonyls were, in decreasing order, formaldehyde, acetaldehyde, benzaldehyde, acetone, m-tolualdehyde, p-tolualdehyde, methacrolein, o-tolualdehyde, 2,5-dimethylbenzaldehyde, and crotonaldehyde. At the Tuscarora Mountain Tunnel, the LD emission factor was 94.9 mg/L for total measured carbonyls; the ten most abundant carbonyls were formaldehyde, acetone, acetaldehyde, heptanal, crotonaldehyde, 2-butanone, propanal, acrolein, methacrolein, and benzaldehyde. The weight class HD 7-8 vehicle emission factor at the Tuscarora Mountain Tunnel was 82.1 mg/L for total measured carbonyls; the ten most abundant carbonyls were formaldehyde, acetaldehyde, acetone, crotonaldehyde, m-tolualdehyde, 2-pentanone, a C5 saturated aliphatic carbonyl, 2-butanone, benzaldehyde, and methacrolein. The most abundant carbonyl was formaldehyde, which accounted for 45.4% (Caldecott, LD vehicles), 40.1% (Tuscarora Mountain, LD vehicles), and 25.8% (Tuscarora Mountain, HD vehicles) of total measured carbonyl emissions. The three most abundant carbonyls, formaldehyde, acetaldehyde, and acetone, together accounted for 63.0% (Caldecott, LD vehicles), 76.5% (Tuscarora Mountain, LD vehicles), and 50.5% (Tuscarora Mountain, HD vehicles) of total carbonyl emissions. At the Tuscarora Mountain Tunnel, HD vehicles emitted more unsaturated carbonyls, aromatic carbonyls, and dicarbonyls (as a percentage of total carbonyl emissions) than did LD vehicles. For LD vehicles, less acetone and more aromatic carbonyls (as a percentage of total carbonyl emissions) were emitted at the Caldecott Tunnel than at the Tuscarora Mountain Tunnel. The highway tunnel studies described in the main body of the report also offered an opportunity to examine the role of the sampling substrate, a critical aspect of the carbonyl sampling protocol. The results are described in Appendix A. Co-located samples, one collected using a DNPH-coated silica gel cartridge and the other using a DNPH-coated C18 cartridge, were collected downstream of KI oxidant scrubbers at the inlet and outlet of the Caldecott Tunnel. Statistical comparisons of the concentrations measured for about 30 carbonyls indicated good agreement between silica gel cartridges and C18 cartridges for about 25 carbonyls, including formaldehyde and acetaldehyde. Concentrations of acetone and 2-butanone measured using C18 cartridges were lower than those measured using silica gel cartridges.

Air Pollutants↗
PubMed2005

[Chemical components of volatiles form withered black poplar leaves with different physiological age].

By the methods of steam distillation and GC-MS, this paper analyzed the chemical components of the volatiles from withered black poplar leaves. The main components of the volatiles from young leaves were(Z)-3-hexenol (44.81% ),4-methyl-1-pentanol (21.85%) and 2-hydroxy-benzaldehyde (15.19%), those from matured leaves were(Z)-3-hexenol (28.71%) and 2-hydroxy-benzaldehyde (10.35%), while in the volatiles from senescent leaves, the main components were 2-hydroxy-benzaldehyde (28.81%) and benzyl alcohol (15.06%). The (Z)-3-hexenol content in the volatiles was evidently decreased with increasing leaf age, while the species and contents of aromatic compounds were in adverse.

Benzyl Alcohol↗
PubMedDate not supplied

Metabolism and covalent binding of [14C]toluene by human and rat liver microsomal fractions and liver slices.

The in vitro metabolism of [14C]toluene by liver microsomes and liver slices from male Fischer F344 rats and human subjects has been compared. Rat liver microsomes produced only benzyl alcohol from toluene. Liver microsomes from human subjects metabolized toluene to benzyl alcohol, benzaldehyde, and benzoic acid. Liver microsomes from one human donor also produced p-cresol and o-cresol. The overall rate of toluene metabolism by human liver microsomes was 9-fold greater than by rat liver microsomes. Human liver microsomal metabolism of benzyl alcohol to benzaldehyde required NADPH and was inhibited by carbon monoxide and high pH (pH 10). but was not inhibited by ADP-ribose or sodium azide. These results suggest that cytochrome P-450, rather than alcohol dehydrogenase, was responsible for the metabolism of benzyl alcohol to benzaldehyde. Human and rat liver slices metabolized toluene to hippuric acid and benzoic acid. The overall rate of toluene metabolism by human liver slices was 1.3-fold greater than by rat liver slices. Cresols and cresol conjugates were not detected in human or rat liver slice incubations. Covalent binding of [14C]toluene to human liver microsomes and slices was 21-fold and 4-fold greater than to the comparable rat liver preparations. Covalent binding did not occur in the absence of NADPH, was significantly decreased by coincubation with cysteine, glutathione, or superoxide dismutase, and was unaffected by coincubation with lysine. Protease and ribonuclease digestion decreased the amount of toluene covalently bound to human liver microsomes by 78% and 27% respectively. Acid washing of human liver microsomes had no effect on covalent binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1986

Changes in aldehyde dehydrogenase occurring during rat hepatocarcinogenesis induced by ethionine combined with dietary choline deficiency.

Chronic exposure to ethionine (0.05%) combined with dietary choline deficiency was used to study changes in aldehyde dehydrogenase (ALDH) activity during hepatocarcinogenesis in male Sprague-Dawley rats. Over a period of 43 weeks, animals were sacrificed at intervals and the ALDH phenotype of normal liver and any lesions was characterized by histochemical analysis, total activity assays, and gel electrophoresis, using propionaldehyde and nicotinamide adenine dinucleotide (NAD+) to detect normal liver ALDH activity and benzaldehyde and nicotinamide adenine dinucleotide phosphate (NADP+) for tumor-associated ALDH. In animals receiving ethionine plus choline deficiency, significant changes in ALDH were observed histochemically by 9 weeks, when there was a distinct shift in activity from its normal centrilobular pattern to a periportal distribution. The first NAD+- and NADP+-dependent ALDH-positive enzyme-altered foci were also seen at 9 weeks. There was no correlation between the ALDH and gamma-glutamyl transpeptidase phenotypes of an individual focus. Areas of cholangiofibrosis, cystic degeneration, and bile duct proliferation were distinctly ALDH negative. No significant changes in benzaldehyde and NADP+ ALDH activity were detectable by total activity assays or gel electrophoresis prior to the appearance of overt neoplasms at 26 weeks. No significant changes in ALDH activity occurred in animals receiving either ethionine or choline deficient diet alone. By histochemistry, total activity assays and gel electrophoresis, only 7 of the 28 (25%) of the hepatic neoplasms examined expressed the tumor-associated ALDH phenotype. An additional five neoplasms had barely detectable levels of benzaldehyde and NADP+ ALDH activity. These results are in striking contrast to changes in ALDH activity occurring during hepatocarcinogenesis induced by other protocols we have tested previously in which from 50 to 96% of all neoplasms were ALDH positive.

Aldehyde Dehydrogenase↗
PubMed1985

Mechanism of oxidative C alpha-C beta cleavage of a lignin model dimer by Phanerochaete chrysosporium ligninase. Stoichiometry and involvement of free radicals.

The hemoprotein ligninase of Phanerochaete chrysosporium Burds. catalyzes the oxidative cleavage of lignin model dimers between C alpha and C beta of their propyl side chains. The model dimers hitherto used give multiple products and complex stoichiometries upon enzymatic oxidation. Here we present experiments with a new model dimer, 1-(3,4-dimethoxyphenyl)-2-phenylethanediol (dimethoxyhydrobenzoin, DMHB) which is quantitatively cleaved by ligninase in air to give benzaldehyde and veratraldehyde according to the stoichiometry: 2DMHB + O2----2PhCHO + 2Ph(OMe)2CHO. Catalytic amounts of H2O2 are required for this aerobic reaction. Under anaerobic conditions, ligninase uses H2O2 as the oxidant for cleavage: DMHB + H2O2----PhCHO + Ph(OMe)2CHO. Electron spin resonance experiments done in the presence of spin traps, 2-methyl-2-nitrosopropane or 5,5-dimethyl-1-pyrroline-N-oxide, show that C alpha-C beta cleavage yields alpha-hydroxybenzyl radicals as intermediate products. Under anaerobic conditions, these radicals react further to give the final aldehyde products. In air, O2 adds to the carbon-centered radicals, probably giving alpha-hydroxybenzylperoxyl radicals which fragment to yield superoxide, benzaldehyde, and veratraldehyde. These results lead us to propose a mechanism for C alpha-C beta cleavage in which attack by ligninase and H2O2 on the methoxylated ring of DMHB yields a cation radical, which then cleaves to give either benzaldehyde and an alpha-hydroxy(dimethoxybenzyl) radical or veratraldehyde and an alpha-hydroxybenzyl radical (cf. Kersten, P. J., Tien, M., Kalyanaraman, B., and Kirk, T.K. (1985) J. Biol. Chem. 260, 2609-2612; Snook, M. E., and Hamilton, G. A. (1974) J. Am. Chem. Soc. 96, 860-869). Similar mechanisms probably apply to the enzymatic C alpha-C beta cleavage of natural lignin.

Basidiomycota↗
PubMed1983

Histochemical localization of aldehyde dehydrogenase during rat hepatocarcinogenesis.

Significant changes in aldehyde dehydrogenase (ALDH) activity occur during chemically induced rat hepatocarcinogenesis. We have developed a procedure for the histochemical localization of hepatic ALDH which has proven extremely useful as an additional probe for studying changes in this enzyme during hepatocarcinogenesis. Frozen sections of fresh tissue were stained for ALDH using either propionaldehyde-NAD to detect normal liver ALDH or benzaldehyde-NADP to detect tumor ALDH. Histochemically, normal liver ALDH activity is strongly centrilobular with only slight periportal activity and produces a characteristic staining pattern. During hepatocarcinogenesis, ALDH staining patterns in grossly normal liver range from normal-appearing to patterns of distinct, intense focal hepatocyte staining with propionaldehyde-NAD and/or benzaldehyde-NADP. ALDH-positive foci are found both in normal regions of tumor-bearing livers and prior to the appearance of gross neoplasms. Neoplastic nodules and carcinomas possess a wide variety of ALDH staining patterns between and within lesions. Neoplasms with elevated ALDH activity with propionaldehyde-NAD and/or benzaldehyde-NADP, as well as with no detectable ALDH, have been observed. Changes in ALDH can be identified histochemically at a time in hepatocarcinogenesis when other analytical methods cannot detect significant changes. Moreover, considerable heterogeneity in expression of tumor ALDH is demonstrable by histochemistry.

Aldehyde Dehydrogenase↗
PubMed1984

Esophageal microsomal metabolism of N-nitrosomethylbenzylamine in the zinc-deficient rat.

Epidemiological studies in China suggest that dietary zinc deficiency and environmental exposure to N-nitrosamine carcinogens, such as N-nitrosomethylbenzylamine (NMBA), are among the factors associated with an increased incidence of esophageal carcinoma in humans. NMBA belongs to a class of nitrosamines which require activation by the cytochrome P-450-dependent mixed-function oxidases in order to be mutagenic. Rats maintained on a zinc-deficient diet exhibited an increased incidence of NMBA-induced esophageal carcinoma when compared to rats on a control diet. The increased tumor formation was associated with an alteration of the microsomal metabolism of NMBA. Weanling male Sprague-Dawley rats were raised on egg protein diets containing 2.3 ppm zinc (low zinc) or 50 ppm zinc (control zinc). Analysis of tissues revealed a rapid decline in the levels of zinc in serum and esophagi of the animals fed the low-zinc diet. Gastric and hepatic zinc content did not differ significantly between the animals fed the low-zinc diet and the animals fed the control zinc diet, even after 6 weeks. Microsomes were prepared from esophageal mucosa, livers, and forestomachs from weanling animals fed these diets for 3 weeks. The rate of formation of benzaldehyde from NMBA by esophageal mucosal microsomes prepared from the rats fed the low-zinc diet was nearly 10-fold higher than that of the rats fed the control zinc diet [0.230 +/- 0.047 (S.E.) versus 0.024 +/- 0.008 nmol/min/mg microsomal protein; p less than 0.001]. The rate of benzaldehyde formation by hepatic microsomes was 0.062 +/- 0.005 nmol/min/mg microsomal protein in the rats fed the low-zinc diet and 0.042 +/- 0.002 nmol/min/mg microsomal protein in the rats fed the control zinc diet (p less than 0.01). The rate of benzaldehyde formation by forestomach microsomes was not detectable in tissue from rats on either diet. This increased rate of NMBA metabolism by esophageal mucosal microsomes from the zinc-deficient rats may explain the increased incidence of esophageal carcinoma in these animals.

Animals↗
PubMed1997

Production of L-phenylacetylcarbinol by free and immobilized yeast cells.

Production of L-phenylacetylcarbinol (L-PAC) through biotransformation of benzaldehyde by free and immobilized cells of the yeast Saccharomyces cerevisiae has been attempted. L-PAC production was found to be maximum (0.4 microliter/ml) when anaerobically grown free cells were used as biocatalyst during aerobic biotransformation for two hours with magnetically stirred bioreactor. Growth under oxygen limited conditions led to accumulation of higher amount of pyruvate decarboxylase enzyme and co-substrate, pyruvate, resulting in higher L-PAC formation. L-PAC yield was low when biotransformations were carried out anaerobically either for aerobically or anaerobically grown free cells. Free cells were found to be more efficient biocatalyst for L-PAC production, as compared with the immobilized cells, with the investigated benzaldehyde concentration (0.3% v/v) and cell density (17.5% w/v). The study has explored and indicated the possibility of optimizing the yield of L-PAC by growing the yeast cells under oxygen limited condition for suitable aerobic mode of benzaldehyde biotransformation.

Acetone↗
PubMed1991

Anaerobic degradation of toluene in denitrifying Pseudomonas sp.: indication for toluene methylhydroxylation and benzoyl-CoA as central aromatic intermediate.

The anaerobic degradation of toluene has been studied with whole cells and by measuring enzyme activities. Cultures of Pseudomonas strain K 172 were grown in mineral medium up to a cell density of 0.5 g of dry cells per liter in fed-batch culture with toluene and nitrate as the sole carbon and energy sources. A molar growth yield of 57 g of cell dry matter formed per mol toluene totally consumed was determined. The mean generation time was 24 h. The redox balance between toluene consumed (oxidation and cell material synthesis) and nitrate consumed (reduction to nitrogen gas and assimilation as NH3) was 77% of expectation if toluene was completely oxidized; this indicated that the major amount of toluene was mineralized to CO2. It was tested whether the initial reaction in anaerobic toluene degradation was a carboxylation or a dehydrogenation (anaerobic hydroxylation); the hypothetical carboxylated or hydroxylated intermediates were tested with whole cells applying the method of simultaneous adaptation; cells pregrown on toluene degraded benzyl alcohol, benzaldehyde, and benzoic acid without lag, 4-hydroxybenzoate and p-cresol with a 90 min lag phase, and phenylacetate after a 200 min lag phase. The cells were not at all adapted to degrade 2-methylbenzoate, 4-methylbenzoate, o-cresol, and m-cresol, nor did these compounds support growth within a few days after inoculation with cells grown on toluene. In extracts of cells anaerobically grown on toluene, benzyl alcohol dehydrogenase, benzaldehyde dehydrogenase, and benzoyl-CoA synthetase (AMP forming) activities were present. The data (1) conclusively show anaerobic growth of a pure culture on toluene; (2) suggest that toluene is anaerobically degraded via benzoyl-CoA; (3) imply that water functions as the source of the hydroxyl group in a toluene methylhydroxylase reaction.

Acyl Coenzyme A↗
PubMed2006

Solid-phase synthesis of tetrahydro-beta-carbolines and tetrahydroisoquinolines by stereoselective intramolecular N-carbamyliminium Pictet-Spengler reactions.

A solid-phase method for the synthesis of tri-, tetra-, and pentacyclic compounds containing tetrahydro-beta-carboline, tetrahydroisoquinoline or analogous scaffolds is presented. The reaction proceeds with high stereoselectivity through an intermediate N-carbamyliminium ion that exclusively converts into Pictet-Spengler-type products with a variety of C-nucleophiles. Amino aldehydes masked with 3-Boc-(1,3)-oxazinane (Box) have been synthesized from amino acids, amino alcohols, or 2-nitro benzaldehydes. The amino moiety of these masked aldehydes has been converted into pentafluorophenyl carbamate to serve as a urea precursor. The building blocks were incorporated at the N-terminal of a resin-supported dipeptide through urea formation. Subsequent treatment with acid liberated the aldehyde quantitatively. A penultimate tryptophan residue gave rise, under the acetic conditions, to a spontaneous intramolecular Pictet-Spengler reaction with the liberated aldehyde. The reaction proceeded with a high degree of stereoselectivity affording tetrahydro-beta-carbolines with a de (de=diastereomeric excess) above 95 % and purity in the range of 90-99 %. This reaction has been extended to a range of other aromatic C-nucleophiles, including substituted indoles, benzenes, pyrene, furan, thiophenes, and benzothiophene with comparable stereoselectivity and purity. Prolonged exposure of the benzaldehyde-derived Pictet-Spengler products to strong acid and air lead to quantitative auto-oxidation which yielded compounds with a 3,4-dihydro-beta-carboline, a 3,4-dihydroisoquinoline, or a similar core structure.

Benzaldehydes↗
PubMed2006

Sequential reactions with amine-terminated monolayers and isolated molecules on H/Si(111).

A simple method for preparing monolayers with terminal amine functionality is demonstrated. A gas-phase photochemical reaction of 1,3-diaminopropane with a H-terminated Si(111) surface results in the molecules covalently attaching to the surface, primarily through the formation of a Si--N bond. These monolayers are characterized by scanning tunneling microscopy (STM) and high-resolution electron energy loss spectroscopy (HREELS). The reactivity of the terminal amine is confirmed by exposing the monolayer to benzaldehyde, resulting in the formation of an imine link and the grafting of phenyl rings onto the surface. For short irradiation times, this reaction leads to the formation of isolated amine groups on an otherwise pristine H-terminated surface. STM and HREELS studies of the benzaldehyde reaction on these low-coverage surfaces (less than 0.005 monolayers) indicate that the reaction is restricted to the reactive amine groups, leaving the remainder of the surface unaffected. This simple approach for a sequential coupling reaction is expected to facilitate attachment of more complex molecules (molecular switches, biomolecules) for single-molecule STM studies.

Benzaldehydes↗
PubMed1994

Requirement of a second oxidation equivalent for ferryl oxygen transfer to styrene in the epoxidation catalyzed by myoglobin-H2O2.

Ferric myoglobin (Mb) is oxidized by H2O2 to a ferryl (FeIV = O) species and a protein radical, whereas ferrous Mb is similarly oxidized to the ferryl species without the protein radical. The protein radical is unstable and decays within 5 min, but the ferryl species is stable for more than 1 h. Previous studies have shown that styrene is oxidized to styrene oxide and benzaldehyde by ferric Mb and H2O2. We demonstrate here that the ferryl species produced from ferrous equine Mb and H2O2 does not epoxidize styrene. Furthermore, the EPR signal intensity of the protein radical formed from ferric equine Mb and the ability to oxidize styrene decrease in parallel as a function of the time separating the addition of H2O2 and styrene. The ability to oxidize styrene as a function of time after addition of H2O2 is lost much more rapidly with the H64V/K102Q/Y103F/Y146F/Y151F mutant of sperm whale Mb than with the native protein or the Y146F/Y151F mutant. The results indicate that styrene epoxidation requires a two-electron oxidized species of Mb in which the ferryl (FeIV = O) complex is coupled to a protein or highly transient (undetectable) porphyrin radical. Benzaldehyde formation appears to be catalyzed by the same oxidizing species. Styrene oxidation thus differs from linoleic acid oxygenation, which is catalyzed by the ferryl species alone.

Animals↗
PubMed1981

Mercapturic acids as metabolites of aromatic aldehydes and alcohols.

After administration of substituted (CH3, OH, OCH3, F, CL, Br, NO2) benzaldehyde or benzyl alcohols in the rat an enhanced urinary thioether excretion was found in some cases. With p-substituted benzaldehyde only occasionally a slight increase could be shown, but with o-substituted aldehydes and alcohols thioether excretions amounted up to 13% of the dose. Mercapturic acids were isolated and identified by synthesis, mass-, and n.m.r.-spectrometry as the arylmethyl thioethers of N-acetylcysteine. Steric hindrance by o-substituents must be the main cause of a relative decrease in oxidation to the carboxylic acid and an increase of the importance of both the reduction of the aldehydes and the reaction of the alcohols, presumably to sulphuric acid esters, as intermediates for the alkylation of glutathione. Consequently, previous administration of pyrazole, an inhibitor of alcohol dehydrogenase, caused an even larger thioether excretion after injection of o-chlorobenzyl alcohol.

Acetylcysteine↗
PubMed1994

Quantifying relative importance of maxillary palp information on the olfactory behavior of Drosophila melanogaster.

Maxillary palps have been proposed as secondary olfactory organs, after the antennae, in Drosophila melanogaster. Our study tries to establish the quantitative importance of both organs as olfactory information mediators. Dose-response curves for three odorants: ethyl acetate, propionaldehyde and benzaldehyde were carried out for comparing olfaction in either complete animals or flies surgically deprived of antennae. Antennaless flies tested in our behavioral assay showed indifferent, attractant and repellent responses depending on concentration, similarly as normal flies do. However, they clearly displayed less sensitivity than normal flies. The range of concentrations they were able to perceive was correlated to antennal sensitivity approximately by a factor 1:10 for ethyl acetate and benzaldehyde, and between 1:10 and 1:100 at high concentrations of propionaldehyde. A complementary experiment was performed to test changes in olfactory behavior produced by removing maxillary palps in the presence of antennae. At high concentrations of odorant, responses to ethyl acetate and propionaldehyde experienced small changes when both palps were removed. Results are compatible with a summation model of all olfactory information reaching the brain either through antennae or palps.

Acetates↗
PubMed1995

Transformation of o-xylene to o-methyl benzoic acid by a denitrifying enrichment culture using toluene as the primary substrate.

A highly enriched denitrifying mixed culture transformed o-xylene co-metabolically along with toluene by methyl group oxidation. o-Methyl benzaldehyde and o-methyl benzoic acid accumulated transiently as metabolic products of o-xylene transformation. Transformation of o-methyl benzyl alcohol and o-methyl benzaldehyde occurred independently of toluene degradation and resulted in the formation of a compound coeluting with o-methyl benzoic acid on a gas chromatograph. The co-metabolic relationship between toluene and o-xylene could be attributed to a mechanism linked to the initial oxidation of the methyl group.

Bacteria, Anaerobic↗
PubMed1991

Comparison of known and suspected pheromonal constituents in males of African ticks, Amblyomma hebraeum Koch and Amblyomma variegatum (Fabricius).

Three low molecular weight compounds were found in hexane:diethyl ether extracts of fed males of the African ticks, Amblyomma variegatum (tropical bont tick) and A. hebraeum (bont tick), namely, o-nitrophenol, methyl salicylate and 2,6-dichlorophenol. These same compounds were also fond in a rinse of fed A. variegatum males, but were absent or present in only trace amounts in a rinse of fed A. hebraeum males, o-Nitrophenol and methyl salicylate were present in much higher concentrations (i.e., amounts/tick) in A. variegatum than in A. hebraeum. 2,6-Dichlorophenol was also more abundant in A. variegatum than in A. hebraeum, but the differences were not as great as with the former two compounds. Extraction in hexane over a 3-week period revealed four additional compounds, benzaldehyde, benzyl alcohol, benzothiazole and nonanoic acid. The first three compounds were found in males of both species; nonanoic acid was found only in A. hebraeum males. Published reports consistently show strong attraction by o-nitrophenol and methyl salicylate for both sexes of the two bont tick species; 2,6-dichlorophenol and benzaldehyde have been reported to be attractive to both sexes of A. hebraeum. The possible roles of these compounds, as well as others occasionally reported from A. hebraeum and A. variegatum, as components of the aggregation/attachment pheromone or other pheromones is discussed.

Animals↗