H. W. Gardner

United States Department of Agriculture, Washington, D. C., DC, United States

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Publications (37)78.19 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Gardner, H. W., Miernyk, J. A., Christianson, D. D. and Khoo, U. 1987. Isolation and characterization of an amyloplast envelope-enriched fraction from immature maize endosperm.A 10000–100000 g pellet obtained by centrifugation of homogenates from immature (25 days after pollination) de-embryonated maize (Zea mays L., cv. W64A-normal and a typical hybrid) kernels was further fractionated by sedimentation on discontinuous sucrose density gradients. Particles with the highest carotenoid content (0.68% by weight carotenoids based upon total lipid) sedimented at densities of 1.083-1.106 g ml-1, coincident with the plastid envelope marker enzyme, galacto-syltransferase (EC 2.4.1.46). Lipids extracted from the carotenoid-rich fraction were mainly digalactosyldiacylglycerols, monogalactosyldiacylglycerols, phosphatidylcholines, phosphatidylinositols and phosphatidylglycerols, in order of molar abundance. With increasing particle density (>1.106 g ml1) the phospholipid and neutral lipid content increased, and the proportion of carotenoids and galactolipids decreased. Electron micrographs of the carotenoid-rich fraction revealed vesicles ranging in size from < 0.1 to 0.5 um, as well as smaller granular membranes. The carotenoid-rich membrane fraction was progressively more difficult to isolate as the endosperm matured, and freezing the immature endosperm prevented subsequent isolation. The lipid and enzyme composition and ultrastructural characteristics of the isolated fraction suggest that it is composed of amyloplast envelope vesicles.
    Physiologia Plantarum 02/2008; 69(3):541 - 549. DOI:10.1111/j.1399-3054.1987.tb09238.x · 3.26 Impact Factor
  • H. W. Gardner, D. Weisleder, E. C. Nelson
    The Journal of Organic Chemistry 04/2002; 49(3). DOI:10.1021/jo00177a024 · 4.64 Impact Factor
  • H. W. Gardner, R. J. Bartelt, D. Weisleder
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    ABSTRACT: A facile, efficient synthesis of 4-hydroxy-2(E)-nonenal is presented as an alternative to the approaches published previously, which either employed four to six separate steps or furnished low yields. The commercially available 3(Z)-nonenol was sequentially oxidized into 3,4-epoxynonanol by 3-chloroperoxybenzoic acid followed by oxidation of the alcohol by periodinane to afford 4-hydroxy-2(E)-nonenal by this two-step procedure in 48±7% yield.
    Lipids 08/1992; 27(9):686-689. DOI:10.1007/BF02536025 · 2.35 Impact Factor
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    H W Gardner, D Weisleder, R D Plattner
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    ABSTRACT: Hydroperoxide lyase (HPLS) activity in soybean (Glycine max) seed/seedlings, leaves, and chloroplasts of leaves required detergent solubilization for maximum in vitro activity. On a per milligram of protein basis, more HPLS activity was found in leaves, especially chloroplasts, than in seeds or seedlings. The total yield of hexanal from 13(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid (13S-HPOD) from leaf or chloroplast preparations was 58 and 66 to 85%, respectively. Because of significant competing hydroperoxide-metabolizing activities from other enzymes in seed/seedling preparations, the hexanal yields from this source were lower (36-56%). Some of the products identified from the seed or seedling preparations indicated that the competing activity was mainly due to both a hydroperoxide peroxygenase and reactions catalyzed by lipoxygenase. Different HPLS isozyme compositions in the seed/seedling versus the leaf/chloroplast preparations were indicated by differences in the activity as a function of pH, the K(m) values, relative V(max) with 13S-HPOD and 13(S)-hydroperoxy-cis-9,trans-11,cis-15-octadecatrienoic acid (13S-HPOT), and the specificity with different substrates. With regard to the latter, both seed/seedling and chloroplast HPLS utilized the 13S-HPOD and 13S-HPOT substrates, but only seeds/seedlings were capable of metabolizing 9(S)-hydroperoxy-trans-10,cis-12-octadecadienoic acid into 9-oxononanoic acid, isomeric nonenals, and 4-hydroxynonenal. From 13S-HPOD and 13S-HPOT, the products were identified as 12-oxo-cis-9-dodecenoic acid, as well as hexanal from 13S-HPOD and cis-3-hexenal from 13S-HPOT. In seed preparations, there was partial isomerization of the cis-3 or cis-9 into trans-2 or trans-10 double bonds, respectively.
    Plant physiology 12/1991; 97(3):1059-72. DOI:10.1104/pp.97.3.1059 · 7.39 Impact Factor
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    A.E. Desjardins, H.W. Gardner
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    ABSTRACT: The ability of field strains of Gibberella pulicaris (Fusarium sambucinum) to cause dry rot of potato tubers is related to their ability to metabolize the potato phytoalexin rishitin. All highly virulent field strains studied to date have proven tolerant of and able to metabolize rishitin. Preliminary genetic analysis of one potato-pathogenic field strain, R-6380, suggested that multiple loci might confer rishitin metabolism and that not all of these loci are associated with virulence (A. E. Desjardins and H. W. Gardner, Mol. Plant-microbe Interact. 2:26-34). To investigate these hypotheses, four phenotypically unique meiotic products of a tetratype ascus from a backcross to strain R-6380 were crossed to strains that were low in rishitin tolerance, rishitin metabolism, and virulence. Tetrad progeny from all four crosses were analyzed for these traits. This genetic analysis indicated that rishitin metabolism in strain R-6380 is controlled by genes at two or more loci but that high virulence on potato is associated with only one of these loci. designated as Rim1.
    Phytopathology 04/1991; 81(4). DOI:10.1094/Phyto-81-429 · 2.75 Impact Factor
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    Journal of Agricultural and Food Chemistry 06/1990; 38(6). DOI:10.1021/jf00096a005 · 3.11 Impact Factor
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    ABSTRACT: The potato phytoalexin lubimin displayed a complex pattern of metabolism by strains of the potato pathogen Gibberella pulicaris (anamorph: Fusarium sambucinum). The metabolites 15-dihydrolubimin and isolubimin were common to both lubimin-sensitive and lubimin-tolerant strains. In one lubimin-tolerant strain, several unique metabolites, including the tricyclic compounds cyclodehydroisolubimin and cyclolubimin (2-dihydrocyclodehydroisolubimin) and their epoxides, accumulated at the expense of 15-dihydrolubimin and isolubimin. These tricyclic compounds were not toxic to the lubimin-sensitive strain. These results indicate that a likely pathway for lubimin detoxification in some strains of G. pulicaris involves cyclization of isolubimin to cyclodehydroisolubimin via an unsaturated intermediate. All highly virulent strains tested were tolerant of lubimin and were able to convert lubimin to apparently nontoxic products which is indirect evidence that lubimin detoxification contributes to virulence of G. pulicaris on potato tubers.
    Phytochemistry 01/1989; 28(2-28):431-437. DOI:10.1016/0031-9422(89)80027-5 · 3.35 Impact Factor
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    ABSTRACT: Gibberella pulicaris (anamorph: Fusarium sambucinum) strain R-7715, biotransformed a potato phytoalexin, lubimin, into several compounds. Products forming between 1 and 6 h after addition of lubimin to cultures were two isomers of isolubimin, isomeric 15-dihydrolubimin, cyclodehydroisolubimin, and two isomers of the previously undescribed 2-dehydrolubimin. After 1–2 days, the novel tricyclic compounds, cyclolubimin (2-dihydrocyclodehydroisolubimin) and 11,12-epoxycyclo-dehydroisolubimin, became an increasing proportion of the mixture at the expense of the early products. Incubation of lubimin with the fungus in the presence of 2H2O resulted in labeling at carbon-3 of cyclodehydroisolubimin, indicating that cyclization was directed toward the double bond of a hypethetical precursor, 3,4-dehydroisolubimin, an early product tentatively identified by its mass spectrum.
    Biochimica et Biophysica Acta (BBA) - General Subjects 09/1988; 966(3). DOI:10.1016/0304-4165(88)90084-0 · 3.83 Impact Factor
  • R. D. Plattner, H. W. Gardner
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    ABSTRACT: Intact isomeric methyl 9- and 13-hydroperoxy linoleates are analyzed by chemical ionization (CI) mass spectrometry using a direct exposure probe. Both isobutane and ammonia CI spectra were obtained. With isobutane CI, ions are observed for protonated fragments that are indicative of an acid catalysis mechanism similar to that observed in solution, whereas ammonia CI yields primarily adduct ions. The collisionally activated decomposition daughters of the high mass ions can be used to identify the position of the hydroperoxy group in the isomers studied.
    Lipids 02/1985; 20(2):126-131. DOI:10.1007/BF02534219 · 2.35 Impact Factor
  • H. W. Gardner, R. D. Plattner
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    ABSTRACT: Treatment of isomeric methyl linoleate hydroperoxides with a Lewis acid, BF3, in anhydrous ether led to a carbon-to-oxygen rearrangement that caused cleavage into shorter-chain aldehydes. Methyl (9Z,11E)-13-hydroperoxy-9,11-octadecadienoate afforded mainly hexanal and methyl (E)-12-oxo-10-dodecenoate, whereas methyl (10E,12Z)-9-hydroperoxy-10,12-octadecadienoate cleaved into 2-nonenal and methyl 9-oxononanoate. The 2 aldehydes obtained from each hydroperoxide isomer were uncharacteristic of the complex volatile profile usually obtained by β-scission of oxy radicals derived from homolysis of the hydroperoxide group. Rather, the reaction resembled the one catalyzed by the plant enzyme, hydroperoxide lyase.
    Lipids 04/1984; 19(4):294-299. DOI:10.1007/BF02534458 · 2.35 Impact Factor
  • R. D. Plattner, H. W. Gardner, R. Kleiman
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    ABSTRACT: Chemical ionization (CI) mass spectra of functionally substituted fatty esters are a useful aid in determining molecular weight. Isobutane and ammonia CI mass spectra of various hydroxy, keto, epoxy and hydroperoxy fatty esters are reported and discussed.
    Journal of Oil & Fat Industries 06/1983; 60(7):1298-1303. DOI:10.1007/BF02702104 · 1.62 Impact Factor
  • H W Gardner, R Kleiman
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    ABSTRACT: 1. The degradation of linoleic acid hydroperoxide by cysteine and FeCl3 resulted in formation of a number of oxygenated fatty acids, among which isomeric epoxyoxooctadecenoic and epoxyhydroxyoctadecenoic acids were major products. Pure isomeric hydroperoxides, either 13-L(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid or 9-D(S)-hydroperoxy-trans-10,cis-12-octadecadienoic acid, were transformed into either 12,13-epoxides or 9,10-epoxides, respectively. 2. From 13-L(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid, the epoxides were identified as trans-12,13-epoxy-9-oxo-trans-10-octadecenoic acid, trans-12,13-epoxy-9-hydroxy-trans-10-octadecenoic acid, cis-12,13-epoxy-9-oxo-trans-10-octadecenoic acid, trans-12,13-epoxy-erythro-11-hydroxy-cis(trans)-9-octadecenoic acid and trans-12,13-epoxy-threo-11-hydroxy-cis(trans)-9-octadecenoic acid. 3. The 12,13-epoxides were found to be optically active, indicating that the chiral center of the 13-L(S)-hydroperoxy carbon was retained. 4. Although many epoxy fatty acids previously have been identified as linoleic acid hydroperoxide products, this study reports a more complete structural analysis of the various epoxides and allows an assessment of the mechanisms of their formation from hydroperoxides.
    Biochimica et Biophysica Acta 08/1981; 665(1):113-24. DOI:10.1016/0005-2760(81)90239-3 · 4.66 Impact Factor
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    H. W. Gardner, R. Kleiman
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    ABSTRACT: Either 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid or 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid was treated with the catalyst, cysteine-FeCl3, in the presence of oxygen. Oxohydroxyoctadecenoic acids were among the many products formed as a result of hydroperoxide decomposition. A mixture of 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoic acids (δ-ketols) was produced from either isomeric hydroperoxide. The formation of isomeric δ-ketols from 9-hydroxy-trans-12,13-epoxy-trans-10-octadecenoic acid (epoxyol), a known product of 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid decomposition, implies that the epoxyol is an intermediate. The mechanism was elucidated by the facile conversion of the epoxyol (methyl ester_ to methyl 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoates with a Lewis acid, BF3-etherate.
    Lipids 09/1979; 14(10):848-851. DOI:10.1007/BF02534127 · 2.35 Impact Factor
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    H. W. Gardner, D. Weisleder, R. Kleiman
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    ABSTRACT: A soybean extract or an ethanolic solution of cysteine and ferric chloride catalyzed the conversion of 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid to numerous products among which wastrans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid. When this fatty acid was treated further with the cysteine-ferric chloride solution, 9-hydroxy-12,13-epoxy-10-octadecenoic and 9-oxo-12,13-epoxy-10-octadecenoic acids were formed. Thus,trans-12,13-epoxy-9-hydroperoxy-trans-10-octadecenoic acid probably is an intermediate in the formation of the latter two compounds. Additionally, theerythro andthreo isomers oftrans-12,13-epoxy-11-hydroperoxy-cis-9-octadecenoic acid tenatatively were identified as products.
    Lipids 04/1978; 13(4):246-252. DOI:10.1007/BF02533664 · 2.35 Impact Factor
  • H. W. Gardner, R. Kleiman
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    ABSTRACT: In the presence of oxygen, a crude soy extract converted 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid into numerous products, from which 9-oxo-trans-12,13-epoxy-trans-10-octadecenoic acid was isolated. Additionally, the soy extract oxidized linoleic acid to the oxo-epoxyoctadecenoic acid, presumably via a sequential reaction involving lipoxygenase oxidation of linoleic acid followed by degradation of the resultant linoleic acid hydroperoxide. However, the linoleic acid substrate yielded two isomeric linoleic acid hydroperoxides and because of this, two isomeric oxoepoxyoctadecenoic acids.
    Lipids 11/1977; 12(11):941-944. DOI:10.1007/BF02533315 · 2.35 Impact Factor
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    ABSTRACT: Cysteine reacts with linoleic acid hydroperoxide to yield several products, some of which were identified as fatty acid-cysteine adducts. The addition was catalyzed by ferric chloride (10(-5) M) by initiating free radical reactions. When isomerically pure 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid and cysteine were reacted in 80% ethanol under N2, the major adducts were 9-S-cysteine-13-hydroxy-10-ethoxy-trans-11-octadecenoic acid (I) and 9-S-cysteine-10,13-dihydroxy-trans-11-octadecenoic acid (II). When the reaction included both isomers of the hydroperoxide (13- and 9-hydroperoxide) and air, an adduct of 9-oxononanoic acid and cysteine also was isolated. Additional experiments gave information about possible mechanisms of I and II formation.
    Lipids 09/1977; 12(8):655-60. · 2.35 Impact Factor
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    ABSTRACT: Bitter-tasting phosphatidylcholines from hexane-defatted soybean flakes were chromatographically separable from ordinary soy phosphatidylcholines (SPC). The bitter-tasting SPC contain 32% oxygenated fatty acids in addition to palmitic, stearic, oleic, linoleic, and linolenic acids. Identification of these oxygenated acids was based on infrared, ultraviolet, proton nuclear magnetic resonance, and mass spectral characteristics of methyl ester derivatives which were separated and purified by column and thin layer chromatography. The fatty acid methyl esters identified were (a) 15, 16-epoxy-9, 12-octadecadienoate, (b) 12, 13-epoxy-9-octadecenoate, both with double bonds and epoxide groups predominantly ofcis configuration; (c) 13-oxo-9,11-and 9-oxo-10, 12-octadecadienoates; (d) 13-hydroxy-9, 11- and 9-hydroxy-10, 12-octadecadienoates; (e) 9, 10, 13-trihydroxy-11- and 9,12,13-trihydroxy-10-octadecenoates. In addition, trace amounts of (f) 11-hydroxy-9,10-epoxy-12-and 11-hydroxy-12,13-epoxy-9-octadecenoates; (g) 13-oxo-9-hydroxy-10-and 9-oxo-13-hydroxy-11-octadecenoates; (h) 9,10-dihydroxy-12- and 12, 13-dihydroxy-9-octadecenoates; and (i) 9,12,13-dihydroxyethoxy-10- and 9,10,13-dihydroxyethoxy-11-octadecenoates were indicated by mass spectrometry. Dihydroxyethoxy compounds (i) were possibly formed upon extraction of the SPC from flakes by 80% ethanol. Except for the first two epoxy compounds, labelled a and b, the oxygenated fatty acids are similar to the products formed by homolytic decomposition of linoleic acid hydroperoxide. The first two compounds with predominantlycis configuration may occur by action of fatty acid hydroperoxides on an unsaturated fatty acid.
    Lipids 08/1977; 12(7):613-9. DOI:10.1007/BF02533391 · 2.35 Impact Factor
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    ABSTRACT: Cysteine reacts with linoleic acid hydroperoxide to yield several products, some of which were identified as fatty acid-cysteine adducts. The addition was catalyzed by ferric chloride (10−5 M) by initiating free radical reactions. When isomerically pure 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid and cysteine were reacted in 80% ethanol under N2, the major adducts were 9-S-cysteine-13-hydroxy-10-ethoxy-trans-11-octadecenoic acid (I) and 9-S-cysteine-10,13-dihydroxy-trans-11-octadecenoic acid (II). When the reaction included both isomers of the hydroperoxide (13-and 9-hydroperoxide) and air, an adduct of 9-oxononanoic acid and cysteine also was isolated. Additional experiments gave information about possible mechanisms of I and II formation.
    Lipids 07/1977; 12(8):655-660. DOI:10.1007/BF02533760 · 2.35 Impact Factor
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    H W Gardner, D Weisleder
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    ABSTRACT: Catalyzed by 10(-5)M ionic iron in 80% ethanol, N-acetylcysteine added to linoleic acid hydroperoxide, forming a thiobond. Reaction of a specific isomer of hydroperoxide, 13-hydroperoxy-trans-11, cis-9-octadecadienoic acid, and N-acetylcysteine, forms a number of products, of which two were identified as addition compounds. One addition product was 9-S-(N-acetylcysteine)-13-hydroxy-10-ethoxy-trans-11-octadecenoic acid, and the other was 9-S-(N-acetylcysteine)-10, 13-dihydroxy-trans-11-octadecenoic acid.
    Lipids 03/1976; 11(2):127-34. DOI:10.1007/BF02532662 · 2.35 Impact Factor
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    ABSTRACT: We have shown unequivocally that the positional specificity of gamma-ketol formation by a corn germ enzyme was different from that observed previously by others with an alfalfa seedling enzyme. When the pure positional isomers of linoleic acid hydroperoxide served as substrates, the corn germ enzyme formed one of two gamma-ketols: 12-oxo-9-hydroxy-trans-10-octadeconoic acid from 13-hydroperoxys-10-octadecenoic acid from 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (99+% pure) and 10-oxo-13-hydroxy-trans-11-octadecenoic acid from 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid (96% pure). Also isolated from these reactions was one of two alpha-ketols commonly found as a result of catalysis by linoleic acid hydroperoxide isomerase: 12-oxo-13-hydroxy-cis-9-octadecenoic acid from the 13-hydroperoxide and 10-oxo-9-hydroxy-cis-12-octadecenoic acid from the 9-hydroperoxide. Evidence is offered that gamma-ketol formation is catalyzed by linoleic acid hydroperoxide isomerase, the same enzyme responsible for alpha-ketol production.
    Lipids 11/1975; 10(10):602-8. DOI:10.1007/BF02532724 · 2.35 Impact Factor