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PubMed2004

Laccase-catalyzed mediated oxidation of benzyl alcohol: the role of TEMPO and formation of products including benzonitrile studied by nanoelectrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

Substituted benzyl alcohol was oxidized enzymatically with a laccase-mediator system and the products were investigated as a function of time by nanoelectrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (nanoESI-FTICRMS). With Trametes versicolor laccase (TVL), the mediator, 2,2',6,6'-tetramethylpiperidine-N-oxyl radical (TEMPO), undergoes oxidation and forms oxoammonium ion. Oxidized TEMPO oxidizes the alcohol and is simultaneously reduced to the N-OH form. The laccase then restores TEMPO back to the normal radical form and the oxidation cycle starts again. The role of TEMPO and the structures of its oxidized and reduced forms in the enzymatic oxidation process were clarified in collision-induced dissociation experiments and gas-phase hydrogen/deuterium (H/D) exchange reactions. The amounts of enzyme and mediator were significant for product formation: with greater amounts overoxidation products, the corresponding benzoic acid and benzonitrile were formed. Smaller amounts of laccase and mediator generated benzaldehyde in high yield. The reaction pathway for benzonitrile formation is discussed and it is suggested to start from benzaldehyde and the ammonia in the ammonium acetate buffer.

Benzyl Alcohol↗
PubMed2003

Blocking sensory inputs to identified antennal glomeruli selectively modifies odorant perception in Drosophila.

Neural coding of sensory input is a major unsolved issue in neuroscience. Current experimental methods rely on neural activity recording or visualization following sensory stimulation. Most of them, however, do not include behavioral correlates on the actual perception by the animal. We present a novel approach to address olfaction and coding in adult Drosophila. Sensory input was selectively blocked in two subsets of sensory neurons that project to different, albeit overlapping, groups of central targets, by means of tetanus toxin expressed under the control of the yeast transcription factor Gal4. Glomeruli DL1, DL2, VM1, and VM4 were tested following stimulation with benzaldehyde, ethyl acetate, propionic acid, butanol, or acetone at various concentrations. The behavioral response was found to be modified in an odorant-specific and a concentration-dependent manner. Sensory input to DL2 and, to a minor extent, VM1 and/or VM4, appear to be required for benzaldehyde perception, while acetone is processed through DL1. None of these glomeruli, however, seem necessary for butanol perception. In addition, sexual differences were observed for some stimuli. These results demonstrate the behavioral relevance of odor representation as maps of glomerular activity generated in the antennal lobes following specific sensory input. The strategy used here should be useful to characterize olfactory coding, as new and selective Gal4 lines become available.

Animals↗
PubMed1992

Olfactory physiology in the Drosophila antenna and maxillary palp: acj6 distinguishes two classes of odorant pathways.

This article provides characterization of the electrical response to odorants in the Drosophila antenna and provides physiological evidence that a second organ, the maxillary palp, also has olfactory function in Drosophila. The acj6 mutation, previously isolated by virtue of defective olfactory behavior, affects olfactory physiology in the maxillary palp as well as in the antenna. Interestingly, abnormal chemosensory jump 6 (acj6) reduces response in the maxillary palp to all odorants tested except benzaldehyde (odor of almond), as if response to benzaldehyde is mediated through a different type of odorant pathway from the other odorants. In other experiments, different parts of the antenna are shown to differ with respect to odorant sensitivity. Evidence is also provided that antennal response to odorants varies with age, and that odorants differ in their age dependence.

Animals↗
PubMed1997

Purification and characterization of hepatic aldehyde oxidase in male and female mice.

To examine whether the hepatic aldehyde oxidases of male and female mice, which exhibit sex-related differences in benzaldehyde oxidation, are qualitatively different, we purified the enzymes from untreated male and female ddy mice and testosterone-pretreated female mice by sequential chromatography of benzamidine-Sepharose 6B and DEAE-5PW columns and characterized the enzymes. Purified enzymes from untreated male and female mice and from testosterone-treated females gave a single protein band at M(r) 265K and M(r) 138K on native and SDS-polyacrylamide gradient gel electrophoresis, respectively. The susceptibilities of the enzymes from both sexes to inhibitors such as menadione, norharman, quinacrine, estradiol, and SKF 525-A were also indistinguishable. However, the K(m) values for benzaldehyde, p-dimethylaminocinnamaldehyde, and 2-hydroxypyrimidine were two- to fourfold higher in the untreated female enzyme than in the untreated male enzyme, while the testosterone-induced female enzyme showed K(m) values similar to those of the male enzyme. These results indicate that the hepatic aldehyde oxidases of the sexes are quite similar with respect to molecular size and susceptibility to inhibitors, but their kinetic properties are somewhat different, suggesting the existence of microheterogeneity in sex differences. It also suggests that treatment of female mice with testosterone might induce the male-type enzyme.

Aldehyde Oxidase↗
PubMed1997

Fluorimetric detection of aldehyde dehydrogenase activity in human blood, saliva, and organ biopsies and kinetic differentiation between class I and class III isozymes.

Two highly fluorogenic aldehydes, 7-methoxy-1-naphthaldehyde (MONAL-71) and 6-methoxy-2-naphthaldehyde (MONAL-62), were examined as indicators of the aldehyde dehydrogenase (ALDH) activity in human tissue homogenates and accessible body fluids. Both compounds were previously found to be excellent substrates for the ALDH from erythrocytes and for the purified class I (cytosolic) ALDH from human liver. By contrast, only MONAL-62, but not the isomeric MONAL-71, was oxidized by class III ALDH present in human saliva. The apparent Km for the former compound reacting with salvia ALDH is 0.24 microM, with the reaction rate (Vmax) close to that of benzaldehyde oxidation. There is also a fully competitive inhibition of the fluorogenic oxidation of the MONAL-62 by benzaldehyde. Both NAD+ and NADP+ can be used as oxidants in this reaction, with comparable rates, a fact previously reported for the human class III aldehyde dehydrogenase. In human liver homogenate (cytosolic + microsomal fraction), the ALDH activity is easily detectable using either MONAL-71 or MONAL-62, with specific activities of approximately 2.5 and 3.2 units per gram of protein, respectively. The low apparent Km values, 0.85 and < 0.03 microM, respectively, together with the inhibition profile by propionic aldehyde (ID50 in the micromolar range) indicate that both compounds are oxidized primarily by the class I ALDH, further confirmed by low activity (0.4 U/g) with NADP+ as oxidant. By contrast, in human stomach, containing mostly class III ALDH, the activity measured with MONAL-71, 0.4 U/g, is much lower than that with MONAL-62 (5.1 U/g with NAD+ and 3.1 U/g with NADP+), the latter being virtually insensitive to 1 mM propionic aldehyde. Hence, in a stomach homogenate, class I and class III ALDH activities can be measured selectively with the two fluorogenic substrates described. In all experiments, the activity of aldehyde oxidase was at least 10-fold lower than that of the ALDH. Addition of 5 mM 4-methylpyrazole, a known inhibitor of the alcohol dehydrogenase, did not change the resultant ALDH activities by more than 10%, indicating lack of interference by the former enzyme. A preliminary screening of two liver tumour samples showed diminished class I ALDH activities (0.7 and 0.03 U/g), but no evidence for class III ALDH induction. The above observations are discussed in relation to the mechanism of detoxication of cyclophosphamide.

Aldehyde Dehydrogenase↗
PubMed1999

Preparation, Characterization, and Catalytic Properties of Ultrafine Mixed Fe-Mo Oxide Particles.

Ultrafine mixed Fe-Mo oxide particles are prepared by the sol-gel technique using citric acid as a complex agent. The formation process of the ultrafine oxides is studied by using XRD, DTA-TG, FT-IR, TEM, and BET surface area measurement. It is found that the morphology and structure of the oxide particles are significantly dependent on the process parameters such as thermal treatment temperature (T), pH of the starting solution, and the molar ratio of citric acid to metallic ions (L/M). The formation temperature of crystalline Fe(2)(MoO(4))(3) by the sol-gel process is much lower than that by the coprecipitation method. The catalytic properties of ultrafine Fe-Mo oxide particles are tested and compared with those of large oxide particles having the same composition. It is shown that for selective oxidation of toluene to benzaldehyde the ultrafine Fe-Mo oxide particles exhibit higher benzaldehyde selectivity and toluene conversion than the large oxide particles. The unique catalytic properties of ultrafine Fe-Mo oxide particles may be correlated to the higher mobility of lattice oxygen species in the ultrafine oxide particles and their higher BET surface area. Copyright 1999 Academic Press.

Journal Article↗
PubMed1997

A review of the interactions between milk proteins and dairy flavor compounds.

The effect of sodium caseinate and whey protein concentrate on vanillin, benzaldehyde, citral, and d-limonene was determined by quantitative descriptive analysis deviation from reference. A trained taste panel evaluated samples containing a single flavor compound in 2.5% sucrose solution against a reference sample. Vanillin, benzaldehyde, and d-limonene flavor intensity decreased as the concentration of whey protein concentrate increased. In a separate study, the ability of delipidated methyl ketones to bind straight and branched chain methyl ketones was determined. The concentration of straight chain methyl ketones bound by the milk protein powder was inversely proportional to the size of the ligand. Branched chain methyl ketones did not exhibit a trend in binding based on ligand size.

Animals↗
PubMed1994

Identification of vertebrate volatiles stimulating olfactory receptors on tarsus I of the tick Amblyomma variegatum Fabricius (Ixodidae). I. Receptors within the Haller's organ capsule.

Gas chromatography-coupled electrophysiological recordings (GC-EL) from olfactory sensilla within the capsule of Haller's organ of the tick Amblyomma variegatum indicate the presence of a number of stimulants in rabbit and bovine odours, and in steer skin wash. Some of these stimulants were fully identified by gas chromatography-mass spectrometry analysis and by matching electrophysiological activity of synthetic analogues as: 1) hexanal, 2-heptenal, nonanal, furfural, benzaldehyde, and 2-hydroxybenzaldehyde (in all extracts); 2) heptanal, 2-, 3-, and 4-methylbenzaldehyde, and gamma-valerolactone (only in bovine and rabbit odour). Careful examination of the electrophysiological responses permit characterization of 6 receptor types: 1) a benzaldehyde receptor, 2) a 2-hydroxybenzaldehyde receptor, 3) three types of receptors responding differently to aliphatic aldehydes, and 4) a lactone receptor.

Adult↗
PubMed1991

Anaerobic degradation of cresols by denitrifying bacteria.

The initial reactions in anaerobic metabolism of methylphenols (cresols) and dimethylphenols were studied with denitrifying bacteria. A newly isolated strain, possibly a Paracoccus sp., was able to grow on o- or p-cresol as sole organic substrate with a generation time of 11 h; o- or p-cresol was completely oxidized to CO2 with nitrate being reduced to N2. A denitrifying Pseudomonas-like strain oxidized m- or -p-cresol as the sole organic growth substrate completely to CO2 with a generation time of 14 h. Demonstration of intermediates and/or in vitro measurement of enzyme activities suggest the following enzymatic steps: (1) p-Cresol was metabolized by both strains via benzoyl-CoA as central intermediate as follows: p-cresol----4-OH-benzaldehyde----4-OH-benzoate----4-OH-benzoyl-CoA----be nzoyl-CoA. Oxidation of the methyl group to 4-OH-benzaldehyde was catalyzed by p-cresol methylhydroxylase. After oxidation of the aldehyde to 4-OH-benzoate, 4-OH-benzoyl-CoA is formed by 4-OH-benzoyl-CoA synthetase; subsequent reductive dehydroxylation of 4-OH-benzoyl-CoA to benzoyl-CoA is catalyzed by 4-OH-benzoyl-CoA reductase (dehydroxylating). (2) o-Cresol was metabolized in the Paracoccus-like strain via 3-CH3-benzoyl-CoA as central intermediate as follows: o-cresol----4-OH-3-CH3-benzoate----4-OH-3-CH3-benzoyl-CoA----3-CH3-benzo yl-CoA. The following enzymes were demonstrated: (a) An enzyme catalyzing an isototope exchange reaction between 14CO2 and the carboxyl of 4-OH-3-CH3-benzoate; this activity is thought to be a partial reaction catalyzed by an o-cresol carboxylase. (b) 4-OH-3-CH3-benzoyl-CoA synthetase (AMP-forming) activating the carboxylation product 4-OH-3-CH3-benzoate to its coenzyme A thioester. (c) 4-OH-3-CH3-benzoyl-CoA reductase (dehydroxylating) catalyzing the reductive dehydroxylation of the 4-hydroxyl group with reduced benzyl viologen as electron donor to yield 3-CH3-benzoyl-CoA. This thioester may also be formed by action of a coenzyme A ligase when 3-CH3-benzoate is metabolized. 2,4-Dimethylphenol was metabolized via 4-OH-3-CH3-benzoate and further to 3-CH3-benzoyl-CoA. (3) The initial reactions of anaerobic metabolism of m-cresol in the Pseudomonas-like strain were not resolved. No indication for the oxidation of the methyl group nor for the carboxylation of m-cresol was found. In contrast, 2,4- and 3,4-dimethylphenol were oxidized to 4-OH-3-CH3- and 4-OH-2-CH3-benzoate, respectively, probably initiated by p-cresol methylhydroxylase; however, these compounds were not metabolized further.

Anaerobiosis↗
PubMed1990

Isolation and characterization of a bacterium that mineralizes toluene in the absence of molecular oxygen.

A bacterium tentatively identified as a Pseudomonas sp. was isolated from a laboratory aquifer column in which toluene was degraded under denitrifying conditions. The organism mineralized toluene in pure culture in the absence of molecular oxygen. In carbon balance studies using [ring-UL-14C]toluene, more than 50% of the radioactivity was recovered as 14CO2. Nitrate and nitrous oxide served as electron acceptors for toluene mineralization. The organism was also able to degrade m-xylene, benzoate, benzaldehyde, p-cresol, p-hydroxy-benzaldehyde, p-hydroxybenzoate and cyclohexanecarboxylic acid in the absence of molecular oxygen.

Anaerobiosis↗
PubMedDate not supplied

The stability studies and in vitro hepatic microsomal metabolism of some alpha-phenyl-N-substituted nitrones in rats.

Nitrones are a very important class of synthetic chemicals as synthetic intermediates, antioxidant agents, and metabolic oxidation products of secondary amines and imines used drug, food, cosmetic and printing industry. In the present study, the stability experiments and in vitro metabolism studies using rat microsomal preparations fortified with NADPH were carried out using three different alpha-phenyl-N-substituted nitrones ie alpha-phenyl-N-tert-butylnitrone (PTBN), alpha-(2,6-dichlorophenyl)-N-phenylnitrone (DCPPN) and alpha-phenyl-N-adamantanylnitrone (PADN). The separation of these compounds from the potential degradation, isomerization and metabolic products were performed using a reverse phase HPLC system with a diodearray uv detection. Following stability experiments at 37 degrees C using methanolic nitrone solutions, it was observed that PTBN produced trace amounts of benzaldehyde and the corresponding amide. DCPPN also produced trace amounts of amide. After 12 hours, the amount of the amide significantly increased. PADN produced trace amount of benzaldehyde but not any amide. The proposed compounds were incubated with rat microsomal preparations fortified with NADPH, extracted into dichloromethane (DCM) and finally evaporated under nitrogen in the dark conditions. PTBN was metabolized into corresponding amide whereas DCPPN and PADN did not. With all of the substrates, the corresponding aldehydes are observed with both test and control tubes using denaturated microsomes and without co-factors.

Animals↗
PubMed2005

Characterization of Sphingomonas aldehyde dehydrogenase catalyzing the conversion of various aromatic aldehydes to their carboxylic acids.

An aldehyde dehydrogenase gene, designated phnN, was isolated from a genome library of the 1,4-dimethylnaphthalene-utilizing soil bacterium, Sphingomonas sp. 14DN61. Escherichia coli expressing the phnN gene converted 1,4-dihydroxymethylnaphthalene to 1-hydroxymethyl-4-naphthoic acid. The putative amino acid sequence of the phnN gene product had 31-42% identity with those of NAD(+)-dependent short-chain aliphatic aldehyde dehydrogenases and a secondary alcohol dehydrogenase. The NAD(P)(+)-binding site and two consensus sequences involved in the active site for aldehyde dehydrogenase are conserved among these proteins. The PhnN enzyme purified from recombinant E. coli showed broad substrate specificity towards various aromatic aldehydes, i.e., 1- and 2-naphaldehydes, cinnamaldehyde, vanillin, syringaldehyde, benzaldehyde and benzaldehydes substituted with a hydroxyl, methyl, methoxy, chloro, fluoro, or nitro group were converted to their corresponding carboxylic acids. Interestingly, E. coli expressing phnN was able to biotransform a variety of not only aromatic aldehydes, but also aromatic alcohols to carboxylic acids.

Alcohols↗
PubMed2005

The composition and timing of flower odour emission by wild Petunia axillaris coincide with the antennal perception and nocturnal activity of the pollinator Manduca sexta.

In the genus Petunia, distinct pollination syndromes may have evolved in association with bee-visitation (P. integrifolia spp.) or hawk moth-visitation (P. axillaris spp). We investigated the extent of congruence between floral fragrance and olfactory perception of the hawk moth Manduca sexta. Hawk moth pollinated P. axillaris releases high levels of several compounds compared to the bee-pollinated P. integrifolia that releases benzaldehyde almost exclusively. The three dominating compounds in P. axillaris were benzaldehyde, benzyl alcohol and methyl benzoate. In P. axillaris, benzenoids showed a circadian rhythm with an emission peak at night, which was absent from P. integrifolia. These characters were highly conserved among different P. axillaris subspecies and P. axillaris accessions, with some differences in fragrance composition. Electroantennogram (EAG) recordings using flower-blends of different wild Petunia species on female M. sexta antennae showed that P. axillaris odours elicited stronger responses than P. integrifolia odours. EAG responses were highest to the three dominating compounds in the P. axillaris flower odours. Further, EAG responses to odour-samples collected from P. axillaris flowers confirmed that odours collected at night evoked stronger responses from M. sexta than odours collected during the day. These results show that timing of odour emissions by P. axillaris is in tune with nocturnal hawk moth activity and that flower-volatile composition is adapted to the antennal perception of these pollinators.

Animals↗
PubMed1988

Kinetic characterization of the catalysis of "activated" cyclophosphamide (4-hydroxycyclophosphamide/aldophosphamide) oxidation to carboxyphosphamide by mouse hepatic aldehyde dehydrogenases.

A spectrophotometric assay was developed and utilized to directly characterize aldehyde dehydrogenase-catalyzed oxidation of aldophosphamide to carboxyphosphamide by soluble and solubilized particulate fractions prepared from mouse liver homogenates. Vmax values of 3310 and 1170 nmol/min/g liver were obtained for the soluble and solubilized particulate fractions respectively. Km values were 22 and 84 microM respectively. Alkaline pH optimums were observed in each case. Aldehyde dehydrogenase-catalyzed oxidation of aldophosphamide by the soluble fraction was markedly more temperature responsive. Catalysis of aldophosphamide and acetaldehyde or benzaldehyde oxidation was apparently by the same isozyme(s) in the soluble fraction. Similarly, low Km (acetaldehyde/benzaldehyde) and high Km (acetaldehyde/benzaldehyde) isozymes each apparently catalyzed the oxidation of aldophosphamide in the solubilized particulate fraction. Our findings suggest that (1) oxidation of aldophosphamide to carboxyphosphamide by mouse liver is catalyzed largely by the predominant aldehyde dehydrogenase isozyme present in the soluble fraction (cytosol) of this tissue, and (2) isozymes that catalyze aldophosphamide oxidation are not different from those that catalyze the oxidation of acetaldehyde and benzaldehyde, though the relative contribution of each isozyme within the solubilized particulate fraction to the catalysis of aldophosphamide oxidation remains to be determined.

Aldehyde Dehydrogenase↗
PubMed1994

Comparison of levels of aldehyde oxidase with cytochrome P450 activities in human liver in vitro.

Microsomal suspensions and 9000 g supernatant (S-9) fractions were prepared from the liver tissue of six human multiorgan donors. The S-9 fractions were characterized for cytosolic aldehyde oxidase (AO) activity, using three different substrates [N1-methylnicotinamide (NMN), benzaldehyde and 6-methylpurine]. In addition, human liver NMN oxidase activity was compared with that detected in rat, dog and monkey liver S-9 fractions. As expected, the rank order of NMN oxidase activity was monkey > rat > dog, and in five out of six subjects the activity was lowest in humans (< 2.0 nmol/min/mg). The variation in AO activity among the various human livers was greater for NMN oxidase (> 40 fold) than for 6-methylpurine and benzaldehyde oxidase (< or = 3.6 fold) activity. The corresponding microsomal preparations were characterized with respect to the levels of total cytochrome P450 (CYP) and six CYP-dependent mixed-function monooxygenase (MFO) activities. The variation was greatest for dextromethorphan O-demethylase (CYP2D6) and lowest for N,N-dimethylnitrosamine N-demethylase (CYP2E1) activity (147- vs. 1.4-fold). The inter-sample variation for the total CYP, CYP3A (erythromycin N-demethylase), CYP1A2 (7-ethoxyresorufin O-deethylase), CYP2A6 (coumarin 7-hydroxylase) and CYP2C9/10 (tolbutamide 4-methyl hydroxylase) was 2.2- to 5.3-fold. Furthermore, the levels of AO activity did not correlate with total (spectrally detectable) CYP or any of the CYP form-selective MFO activities.

Adult↗
PubMed1986

Specific synthesis and stereochemical assignment of the diastereomeric 3,5-O-benzylidene-1,2-O-isopropylidene-alpha-D-glucofuranose isomers.

Pyridinium tosylate-catalyzed acetal exchange between benzaldehyde dimethyl acetal and 6-O-(tert-butyldiphenylsilyl)-1,2-O-isopropylidene-alpha-D-glucofu ranose was investigated as an alternative to the original procedure of Brigl and Grüner (condensation of a D-glucose triol with benzaldehyde under zinc halide catalysis) for synthesis of 3,5-O-benzylidene-1,2-O-isopropylidene-alpha-D-glucofuranose. The two routes afford opposite benzylidene diastereoisomers: the traditional procedure leads to the thermodynamically favored isomer (phenyl and C-6 trans), whereas the new sequence gives the cis compound. The orientations and conformations of these isomers were determined after conversion into the corresponding 6-iodides 5 and 7. X-Ray crystallography revealed that the 1,3-dioxane ring of the trans isomer 7 exists in the expected chair, "O-inside" conformation. In contrast, a combination of n.m.r. spectroscopy and molecular-mechanics calculations demonstrated that the same ring of cis diastereomer 5 does not adopt the alternative chair, "H-inside" conformation; instead, it exists in a specific twist form.

Carbohydrate Conformation↗
PubMed1981

Induction of aldehyde dehydrogenase by polycyclic aromatic hydrocarbons in rats.

Short-term intragastric administration of selected polycyclic aromatic hydrocarbons (100 mg/kg daily for 4 days) to male Wistar rats resulted in marked changes in liver cytosolic aldehyde dehydrogenase activity. Non-carcinogenic anthracene, phenanthrene and chrysene produced a 2.5--3-fold increase in the activity assayed with propionaldehyde as substrate and NAD as coenzyme. Weakly carcinogenic 1,2-benzanthracene enhanced aldehyde dehydrogenase activity 9-fold and the potent carcinogens 3,4-benzpyrene and 3-methylcholanthrene 30-fold. With benzaldehyde as substrate and NADP as coenzyme the differences between the groups were even more pronounced. Somewhat similar but less manifest effects on aldehyde dehydrogenase activity were detected also in the liver microsomes and in the postmitochondrial fractions of the small intestinal mucosa. On the basis of their ability to induce aldehyde dehydrogenase activity the compounds could be divided into three groups. This classification was found to correlate well with the carcinogenic potency of the compounds. It appeared that the exposure to polycyclic aromatic hydrocarbons, especially the carcinogenic ones, was followed by synthesis of a new aldehyde dehydrogenase form. This new form was differentiated from the normally existing cytosolic aldehyde dehydrogenase by its ability to oxidize benzaldehyde in the presence of NADP.

Aldehyde Dehydrogenase↗
PubMed1995

Effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers.

The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence.

Biomass↗