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PubMed1987

Old-age deficits in the sense of smell as gauged by thresholds, magnitude matching, and odor identification.

Twenty elderly subjects (70-90 years old) and 20 young control subjects (18-24 years old) underwent three kinds of olfactory testing: absolute thresholds to three odorants (d-limonene, iso-amyl butyrate, benzaldehyde), magnitude matching of these odorants to salt tastes, and odor identification of 30 common substances. For all three odorants elderly subjects' mean threshold significantly exceeded that of the young by about ninefold for d-limonene, about threefold for benzaldehyde, and about twofold for iso-amyl butyrate. These threshold differences predict approximate concentration differences necessary to arouse the same estimated odor strength above the threshold for the elderly and the young. Young subjects also scored better than the elderly in odor identification, even when subjects were given four alternatives from which to select the correct label. Unimpaired olfactory functioning is uncommon in the elderly; correlational tests show that as a group the young have better olfactory ability and show more interindividual uniformity.

Adolescent↗
PubMed1993

Tumour necrotisation in nude mice xenografts by the reversible protein synthesis inhibitor zilascorb(2H).

The deuterated benzaldehyde derivative zilascorb(2H), 5,6-O-benzylidene-d-L-ascorbic acid, was administered once daily by i.v. injection in nude mice with grafted tumours of a human malignant melanoma (E.E.) and ovarian carcinoma (OVCAR-3) origins. Like benzaldehyde, zilascorb(2H) has been shown to induce protein synthesis inhibition at otherwise non-toxic doses in cells grown in vitro, and acts reversibly in the sense that protein synthesis returns to normal shortly after removal of the drug. The present data indicate that daily injections with zilascorb(2H) induce a tumour volume growth inhibitory effect in both tumour xenografts studied. Furthermore, from histological examinations of each single tumour it was found that tumours of drug-treated animals, although smaller than those of placebo-treated (i.e. control) animals, had, on average, a higher necrotic fraction than control tumours. Thus, it is concluded that zilascorb(2H) induces tumour necrotisation and not just inhibition of the rate of tumour cell production. Continued measurement of tumour volume after ended treatment with zilascorb(2H) indicated that surviving tumour cells resumed their normal growth rate immediately. The reversibility of the effect induced by this compound, earlier observed in vitro only, is therefore here confirmed to be valid also in two different tumour xenografts in vivo. The present data accords well with the assumption that protein synthesis inhibition is the primary cellular effect of zilascorb(2H) in vivo. We therefore conclude that zilascorb(2H)-induced cancer cell lethality in tumour xenografts probably comes as a secondary consequence of prolonged protein synthesis inhibition.

Animals↗
PubMed2004

Regioselective HON-addition of bifunctional hydrazone oximes to Pt(IV)-bound nitriles.

Treatment of trans-[PtCl(4)(RCN)(2)](R = Me, Et) with the hydrazone oximes MeC(=NOH)C(R')=NNH(2)(R' = Me, Ph) at 45 degrees C in CH(2)Cl(2) led to the formation of trans-[PtCl(4)(NH=C(R)ON=C(Me)C(R')=NNH(2))(2)](R/R' = Me/Ph 1, Et/Me 2, Et/Ph 3) due to the regioselective OH-addition of the bifunctional MeC(=NOH)C(R')=NNH(2) to the nitrile group. The reaction of 3 and Ph(3)P=CHCO(2)Me allows the formation of the Pt(II) complex trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NNH(2))2](4). In 4, the imine ligand was liberated by substitution with 2 equivalents of bis(1,2-diphenylphosphino)ethane (dppe) in CDCl(3) to give, along with the free ligand, the solid [Pt(dppe)(2)]Cl(2). The free iminoacyl hydrazone, having a restricted life-time, decomposes at 20-25 degrees C in about 20 h to the parent organonitrile and the hydrazone oxime. The Schiff condensation of the free NH(2) groups of 4 with aromatic aldehydes, i.e. 2-OH-5-NO(2)-benzaldehyde and 4-NO(2)-benzaldehyde, brings about the formation of the platinum(II) complexes trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NN=CH(C(6)H(3)-2-OH-5-NO(2))2](5) and trans-[PtCl(2)(NH=C(Et)ON=C(Me)C(Ph)=NN=CH(C(6)H(4)-4-NO(2))2](6), respectively, containing functionalized remote peripherical groups. Metallization of 5, which can be considered as a novel type of metallaligand, was achieved by its reaction with M(OAc)(2).nH(2)O (M = Cu, n= 2; M = Co, n= 4) in a 1:1 molar ratio furnishing solid heteronuclear compounds with composition [Pt]:[M]= 1:1. The complexes were characterized by C, H, N elemental analyses, FAB+ mass-spectrometry, IR, 1H, 13C[1H] and (195)Pt NMR spectroscopies; X-ray structures were determined for 3, 4 and 5.

Journal Article↗
PubMed2005

The dimethyldioxirane-mediated oxidation of phenylethyne.

The product pattern found for the dimethyldioxirane-mediated oxidation of phenylethyne strongly depends on the reaction conditions. Dimethyldioxirane generated in situ from caroate (HSO(5)(-)) and acetone in acetonitrile-water furnishes phenylacetic acid as the main product. With solutions of dimethyldioxirane in acetone, mandelic acid and phenylacetic acid are mainly formed. The relative abundances of the two acids depend on the residual water present in the dimethyldioxirane-acetone solution. Application of thoroughly dried solutions of the reagent effects increased formation of mandelic acid. When phenylethyne is oxidized by dimethyldioxirane transferred into tetrachloromethane, to minimize traces of water even further, oligomeric mandelic acid is obtained. The results are rationalized by the initial formation of phenyloxirene, which is known to equilibrate with phenylformylcarbene and benzoylcarbene. Subsequent Wolff rearrangement produces intermediate phenylketene, which can be trapped by water as phenylacetic acid or suffer from further oxidation to the alpha-lactone of mandelic acid. The alpha-lactone can either react with water to yield mandelic acid or, under anhydrous conditions, to yield oligomeric mandelic acid. In addition to mandelic acid and phenylacetic acid phenylglyoxylic acid, benzoic acid and benzaldehyde are observed as reaction products. The formation of phenylglyoxylic acid by transfer of two oxygen atoms to the unrearranged carbon skeleton of phenylethyne followed by oxygen insertion into the aldehydic C-H bond of the intermediately formed phenylglyoxal is discussed. In a second pathway this acid is formed by partial oxidation of mandelic acid. Benzaldehyde and benzoic acid are explained as products of the oxidative degradation of the alpha-lactone by dimethyldioxirane. Under in situ conditions benzoic acid is also formed by caroate initiated oxidative decarboxylation of phenylglyoxylic acid and/or intermediate phenylglyoxal.

Journal Article↗
PubMed2005

Synthesis, characterisation, reactivity and in vitro antiamoebic activity of hydrazone based oxovanadium(IV), oxovanadium(V) and mu-bis(oxo)bis{oxovanadium(V)} complexes.

Binuclear, mu-bis(oxo)bis{oxovanadium(V)} complexes [(VOL)2(mu-O)2](2 and 7)(where HL are the hydrazones Hacpy-nah I or Hacpy-fah II; acpy = 2-acetylpyridine, nah = nicotinic acid hydrazide and fah = 2-furoic acid hydrazide) were prepared by the reaction of [VO(acac)2] and the ligands in methanol followed by aerial oxidation. The paramagnetic intermediate complexes [VO(acac)(acpy-nah)](1) and [VO(acac)(acpy-fah)](6) have also been isolated. Treatment of [VO(acac)(acpy-nah)] and [VO(acac)(acpy-fah)] with aqueous H2O2 yields the oxoperoxovanadium(V) complexes [VO(O2)(acpy-nah)](3) and [VO(O2)(acpy-fah)](8). In the presence of catechol (H2cat) or benzohydroxamic acid (H2bha), 1 and 6 give the mixed chelate complexes [VO(cat)L](HL =I: 4, HL =II: 9) or [VO(bha)L](HL =I: 5, HL =II: 10). Complexes 4, 5, 9 and 10 slowly convert to the corresponding oxo-mu-oxo species 2 and 7 in DMF solution. Ascorbic acid enhances this conversion under aerobic conditions, possibly through reduction of these complexes with concomitant removal of coordinated catecholate or benzohydroxamate. Acidification of 7 with HCl dissolved in methanol afforded a hydroxo(oxo) complex. The crystal and molecular structure of 2.1.5H2O has been determined, and the structure of 7 re-determined, by single crystal X-ray diffraction. Both of these binuclear complexes contain the uncommon asymmetrical {VO(mu-O)}2 diamond core. The in vitro tests of the antiamoebic activity of ligands I and II and their binuclear complexes 2 and 7 against the protozoan parasite Entamoeba histolytica show that the ligands have no amoebicidal activity while their vanadium complexes 2 and 7 display more effective amoebicidal activity than the most commonly used drug metronidazole (IC50 values are 1.68 and 0.45 microM, respectively vs 1.81 microM for metronidazole). Complexes 2 and 7 catalyse the oxidation of styrene and ethyl benzene effectively. Oxidation of styrene, using H2O2 as an oxidant, gives styrene epoxide, 2-phenylacetaldehyde, benzaldehyde, benzoic acid and 1-phenyl-ethane-1,2-diol, while ethyl benzene yields benzyl alcohol, benzaldehyde and 1-phenyl-ethane-1,2-diol.

Animals↗
PubMed2006

Polymer supported vanadium and molybdenum complexes as potential catalysts for the oxidation and oxidative bromination of organic substrates.

The Schiff base (H2fsal-ohyba) derived from 3-formylsalicylic acid and o-hydroxybenzylamine has been covalently bonded to chloromethylated polystyrene cross-linked with 5% divinylbenzene (abbreviated as PS-H(2)fsal-ohyba, I). Treatment of [VO(acac)2] with PS-H2fsal-ohyba in dimethylformamide (DMF) gave the oxovanadium(iv) complex PS-[VO(fsal-ohyba).DMF] (1). Complex 1 can be oxidized into the dioxovanadium(v) species, PS-K[VO2(fsal-ohyba)] (2) on aerial oxidation in the presence of KOH or into the oxoperoxo species, PS-K[VO(O2)(fsal-ohyba)] (3) in the presence of H2O2 and KOH in DMF suspension. Similarly, PS-[MoO(2)(fsal-ohyba).DMF] (4) has been isolated by the reaction of [MoO2(acac)2] with PS-H2fsal-ohyba. All these complexes have been characterised by various techniques. These complexes catalyse the oxidation of styrene, ethylbenzene and phenol efficiently. Styrene gives five reaction products namely styrene oxide, benzaldehyde, 1-phenylethane-1,2-diol, benzoic acid and phenylacetaldehyde, while ethylbenzene gives benzaldehyde, phenyl acetic acid, styrene and 1-phenylethane-1,2-diol. The oxidation products of phenol are catechol and p-hydroquinone. These catalysts are also able to catalyse the oxidative bromination of salicylaldehyde to 5-bromosalicylaldehyde with ca. 80% selectively in the presence of aqueous 30% H2O2/KBr, a reaction similar to that exhibited by vanadate-dependent haloperoxidases. Their corresponding neat complexes have also been prepared and their catalytic activities have been compared.

Aldehydes↗
PubMed2002

Catalytic reaction profile for NADH-dependent reduction of aromatic aldehydes by xylose reductase from Candida tenuis.

Kinetic substituent effects have been used to examine the catalytic reaction profile of xylose reductase from the yeast Candida tenuis, a representative aldo/keto reductase of primary carbohydrate metabolism. Michaelis-Menten parameters (k(cat) and K(m)) for NADH-dependent enzymic aldehyde reductions have been determined using a homologous series of benzaldehyde derivatives in which substituents in meta and para positions were employed to systematically perturb the properties of the reactive carbonyl group. Kinetic isotope effects (KIEs) on k(cat) and k(cat)/K(m) for enzymic reactions with meta-substituted benzaldehydes have been obtained by using NADH (2)H-labelled in the pro-R C4-H position, and equilibrium constants for the conversion of these aldehydes into the corresponding alcohols (K(eq)) have been measured in the presence of NAD(H) and enzyme. Aldehyde dissociation constants (K(d)) and the hydride transfer rate constant (k(7)) have been calculated from steady-state rate and KIE data. Quantitative structure-activity relationship analysis was used to factor the observed substituent dependence of k(cat)/K(m) into a major electronic effect and a productive positional effect of the para substituent. k(cat)/K(m) (after correction for substituent position) and K(eq) obeyed log-linear correlations over the substituent parameter, Hammett sigma, giving identical slope values (rho) of +1.4 to +1.7, whereas the same Hammett plot for logK(d) yielded rho=-1.5. This leads to the conclusion that electron-withdrawing substituents facilitate the reaction and increase binding to about the same extent. KIE values for k(cat) (1.8) and k(cat)/K(m) (2.7), and likewise k(7), showed no substituent dependence. Therefore, irrespective of the observed changes in reactivity over the substrate series studied no shift in the character of the rate-limiting transition state of hydride transfer occurred. The signs and magnitudes of rho values suggest this transition state to be product-like in terms of charge development at the reactive carbon. Structure-reactivity correlations reveal active-site homologies among NADPH-specific and dual NADPH/NADH-specific yeast xylose reductases and across two aldo/keto reductase families in spite of the phylogenetic separation of the host organisms producing xylose reductase (family 2B) and aldehyde reductase (family 1A).

Alcohol Oxidoreductases↗
PubMed2001

Conversion of amino acids into aroma compounds by cell-free extracts of Lactobacillus helveticus.

AIMS: Lactobacillus helveticus is an essential starter in Swiss-type cheeses such as Emmental. This study was to determine whether cell-free extracts of Lact. helveticus were able to convert free amino acids into neutral volatile aroma compounds at the pH and temperature occurring in cheese. METHODS AND RESULTS: A mix of branched-chain (Leu, Ile, Val), aromatic (Tyr, Phe) and sulphur (Met) amino acids was incubated for 7 days, at pH 5.7 and 24 degrees C, with cell-free extracts of six strains. The amino acids were all transaminated into the corresponding keto acids when an amino group acceptor (alpha-ketoglutaric acid) was provided. Phe and Tyr were transaminated the most efficiently, followed by Leu, Met, Ile and Val. Three major volatile compounds were detected by GC-MS: benzaldehyde, dimethyl disulphide and 2-methyl propanol. Whatever the strain, benzaldehyde was produced in the highest quantity (0.25-1 micromol l(-1) mg(-1) protein). CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus helveticus intracellular enzymes could significantly contribute to the production of aroma compounds from amino acid catabolism.

Amino Acids↗
PubMed2005

Excited state molecular structures and reactions directly determined by ultrafast electron diffraction.

In this communication, we report on the use of ultrafast electron diffraction to determine structural dynamics of excited states and reaction products of isolated aromatic carbonyls, acetophenone and benzaldehyde. For a 266 nm excitation, a bifurcation of pathways is structurally resolved, one leading to the formation of the triplet state (quinoid structure) and another to chemical products: for benzaldehyde the products are benzene and carbon monoxide (hydrogen migration and bond rupture) while those for acetophenone are the benzoyl and methyl radicals (bond rupture). The refined structures are compared with those predicted by theory. These dark structures and their radiationless transitions define the reduced energy landscape for complex reactions.

Journal Article↗
PubMed2006

Ultrafast electron diffraction: excited state structures and chemistries of aromatic carbonyls.

The photophysics and photochemistry of molecules with complex electronic structures, such as aromatic carbonyls, involve dark structures of radiationless processes. With ultrafast electron diffraction (UED) of isolated molecular beams it is possible to determine these transient structures, and in this contribution we examine the nature of structural dynamics in two systems, benzaldehyde and acetophenone. Both molecules are seen to undergo a bifurcation upon excitation (S(2)). Following femtosecond conversion to S(1), the bifurcation leads to the formation of molecular dissociation products, benzene and carbon monoxide for benzaldehyde, and benzoyl and methyl radicals for acetophenone, as well as intersystem crossing to the triplet state in both cases. The structure of the triplet state was determined to be "quinoidlike" of pipi(*) character with the excitation being localized in the phenyl ring. For the chemical channels, the product structures were also determined. The difference in photochemistry between the two species is discussed with respect to the change in large amplitude motion caused by the added methyl group in acetophenone. This discussion is also expanded to compare these results with the prototypical aliphatic carbonyl compounds, acetaldehyde and acetone. From these studies of structural dynamics, experimental and theoretical, we provide a landscape picture for, and the structures involved in, the radiationless pathways which determine the fate of molecules following excitation. For completeness, the UED methodology and the theoretical framework for structure determination are described in this full account of an earlier communication [J. S. Feenstra et al., J. Chem. Phys. 123, 221104 (2005)].

Journal Article↗
PubMed1986

Antifertility activity and toxicity of alpha-chlorohydrin aromatic ketal analogues in male rats.

The antifertility activity and toxicity of alpha-chlorohydrin and seven aromatic ketal derivatives were investigated in male rats. At a dose of 5 mg/kg injected intraperitoneally each day for 14 days, alpha-chlorohydrin and the methoxy benzaldehyde derivative (compound 2) produced complete infertility. The benzaldehyde derivative (compound 1) was 89% effective and the other five compounds 71-25% effective. All compounds except the least effective antifertility agent, the methylbenzaldehyde derivative (compound 3), reduced the motility of sperm recovered from the epididymis. None of the compounds caused a decrease in body or testes weight but some increased adrenal weight.

Animals↗
PubMed2004

Enantioselective direct aldol reactions catalyzed by L-prolinamide derivatives.

l-Prolinamides 2, prepared from l-proline and simple aliphatic and aromatic amines, have been found to be active catalysts for the direct aldol reaction of 4-nitrobenzaldehyde with neat acetone at room temperature. They give moderate enantioselectivities of up to 46% enantiomeric excess (ee). The enantioselectivity increases as the amide N-H becomes a better hydrogen bond donor. l-Prolinamides 3, derived from the reaction of l-proline with alpha,beta-hydroxyamines such that there is a terminal hydroxyl group, show more efficient catalysis and higher enantioselectivities. In particular, catalyst 3h, prepared from l-proline and (1S,2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes under -25 degrees C. Model reactions of benzaldehyde with three enamines derived from the condensation of prolinamides with acetone have been studied by quantum mechanics calculations. The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity. Our results suggest a new strategy in the design of new organic catalysts for direct asymmetric aldol reactions and related transformations.

Journal Article↗
PubMed2006

Selection of biocatalysts for chemical synthesis.

To determine whether microbial chemosensors can be used to find new or better biocatalysts, we constructed Escherichia coli hosts that recognize the product of a biocatalytic conversion through the transcriptional activator NahR and respond by expression of a lacZ or tetA reporter gene. Equipped with a benzaldehyde dehydrogenase (XylC from Pseudomonas putida), the lacZ-based host responded to the oxidation of benzaldehyde and 2-hydroxybenzaldehyde to the corresponding benzoic acids by forming blue colonies, whereas XylC- cells did not. Similarly, the tetA-based host was able to grow under selective conditions only when equipped with XylC, enabling selection of biocatalytically active cells in inactive populations at frequencies as low as 10(-6).

Aldehyde Oxidoreductases↗
PubMed1977

Styrene and related hydrocarbons in subcutaneous fat from polymerization workers.

Subcutaneous fat samples from 25 workers in a styrene polymerization plant have been analyzed for styrene, ethyl benzene, toluene, benzene, and benzaldehyde by gas chromatography. Styrene was found in samples from 13 of 17 workers who had been heavily exposed within the previous 3 days, 5 of 13 having been exposed 2-3 days earlier. Six workers 4-90 days removed from exposure and two 2-3 days removed from low (less than 5 ppm) exposures had no detectable styrene in fat tissue samples. Toluene and ethyl benzene were found in varying amounts in many samples, and benzene was observed in three samples. Benzaldehyde was observed at levels of 5-53 microng/g in all samples. Although urinary metabolites and breath levels of styrene are reported to be detectable for less than 24 hr following exposure, styrene was found in subcutaneous fat from the subjects of this study for as long as 3 days after the most recent occupational exposure. The combination exposures in such a setting are reflected in the variety of hydrocarbons found in fat samples of workers.

Adipose Tissue↗
PubMed1993

Biochemical and histochemical properties of hepatic tumors of rainbow trout, Oncorhynchus mykiss.

Biochemical and histochemical studies were conducted in aflatoxin B1-induced liver tumors in adult rainbow trout. Specific activities of the phase I enzymes, ethoxyresorufin-O-deethylase (EROD), microsomal and cytosolic epoxide hydrolase (mEH and cEH), aldehyde dehydrogenase (ALDH) and DT-diaphorase, and the phase II enzymes, gamma-glutamyltransferase (gamma-GT), glutathione transferase (GST) and uridine diphosphoglucuronyl transferase (UDPGT) were measured. Cryostat sections of tumor and surrounding liver from the same cohorts were analyzed immunohistochemically for cytochrome P450IA1 and histochemically for ALDH (benzaldehyde and hexanal), DT-diaphorase, gamma-GT and uridine diphosphoglucuronyl dehydrogenase (UDPGdH). In tumor tissues, the largest biochemical changes were found with benzaldehyde dehydrogenase, where activity increased from undetectable levels to 7.4 nmol/min/mg protein, and gamma-GT, where activity increased 12-fold over controls. Increases in other enzymes ranged from 1.26 to 2.84 times that of control liver, except EROD, which decreased, and cEH and mEH, which were unchanged. Histochemical analyses showed the induction of ALDH, gamma-GT, DT-diaphorase and UDPGdH, and the depression of cytochrome P450IA1 in hepatic neoplasms. In addition, marker enzyme histochemistry of neoplasms revealed heterogeneous populations of hepatocytes and absence of necrotic areas.

Aflatoxin B1↗
PubMed1988

Inhibition of N-nitrosobenzylmethylamine metabolism and DNA binding in cultured rat esophagus by ellagic acid.

The effect of ellagic acid (EA), a naturally occurring plant phenol, on the metabolism, DNA binding and DNA adduct formation of N-nitrosobenzylmethylamine (NBMA) in cultured explants of rat esophagus was investigated. Explants were incubated in medium containing EA at non-toxic concentrations of 10, 50 and 100 microM for 16 h, followed by the addition of 1 microM [3H]NBMA and EA for 12 h. Explant DNA was isolated by phenol extraction and hydroxylapatite chromatography, and benzaldehyde formation was determined by HPLC analysis of the culture medium. EA produced a significant inhibition in the total covalent binding of NBMA metabolites to DNA and in the production of benzaldehyde in the medium. After acid hydrolysis of the isolated DNA, the NBMA--DNA adducts were separated by HPLC. EA caused a dose-dependent decrease in the formation of N7-methylguanine and O6-methylguanine adducts. These results suggest that EA inhibits both the metabolism of NBMA and the binding of NBMA metabolites to DNA in cultured rat esophagus.

Animals↗
PubMed2004

3 using odor-baited trap trees as sentinels to monitor plum curculio (Coleoptera: Curculionidae) in apple orchards.

In commercial orchards in Massachusetts in 2003, we conducted experiments aimed at developing guidelines for use of perimeter-row trap trees baited with grandisoic acid plus benzaldehyde as sentinels in a practical approach to determining need and timing of insecticide applications against overwintered plum curculios, Conotrachelus nenuphar (Herbst). Evaluations were based on percentages of sampled fruit injured by plum curculio. Trap trees baited with grandisoic acid released at approximately 1 mg/d plus benzaldehyde released at approximately 40 mg/d performed as well as or better than trap trees baited with greater or lesser amounts of these attractants in combination. The distance over which a trap tree baited with such odor was effective in aggregating damage to fruit extended to at least 31-33 m (maximum evaluated) along a perimeter row. Trap trees at corners of orchard blocks were as effective as perimeter-row trap trees midway between corner trees. Within the canopy of a trap tree, damage did not tend significantly to be localized in the vicinity of the odor source but tended to be rather evenly distributed among various sectors of the canopy. Finally, among three candidate thresholds evaluated as a trigger for insecticide application, a threshold of one freshly injured fruit proved better than thresholds of two or four freshly injured fruit out of 50 fruit sampled on a trap tree in assuring that orchard-wide damage would remain below a preset economic injury level of 1%. Our findings lead us to suggest that after a whole-orchard application of insecticide to apple trees in Massachusetts orchards shortly after petal fall, subsequent applications of insecticide against plum curculio can be confined to peripheral-row trees and be driven by a provisional threshold of one freshly injured fruit out of 50 fruit sampled on a perimeter-row trap tree baited with the above-mentioned odor.

Animals↗
PubMed1999

Purification and characterization of a NADPH-dependent aldehyde reductase from mung bean that detoxifies eutypine, a toxin from eutypa lata1

Eutypine (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzaldehyde) is a toxin produced by Eutypa lata, the causal agent of eutypa dieback in the grapevine (Vitis vinifera). Eutypine is enzymatically converted by numerous plant tissues into eutypinol (4-hydroxy-3-[3-methyl-3-butene-1-ynyl] benzyl alcohol), a metabolite that is nontoxic to grapevine. We report a four-step procedure for the purification to apparent electrophoretic homogeneity of a eutypine-reducing enzyme (ERE) from etiolated mung bean (Vigna radiata) hypocotyls. The purified protein is a monomer of 36 kD, uses NADPH as a cofactor, and exhibits a Km value of 6.3 &mgr;M for eutypine and a high affinity for 3- and 4-nitro-benzaldehyde. The enzyme failed to catalyze the reverse reaction using eutypinol as a substrate. ERE detoxifies eutypine efficiently over a pH range from 6.2 to 7.5. These data strongly suggest that ERE is an aldehyde reductase that could probably be classified into the aldo-keto reductase superfamily. We discuss the possible role of this enzyme in eutypine detoxification.

Journal Article↗