Naphthalic Anhydride Induces Imazethapyr Metabolism and Cytochrome P-450 Activity in Maize

Abstract Naphthalic anhydride is a seed-applied herbicide safener which reduces the toxicity of imazethapyr, an imidazolinone herbicide, to maize (Zea mays L.). Protection of maize from imazethapyr was dependent on the amount of naphthalic anhydride applied to the seed. Metabolism of imazethapyr by maize roots and shoots was increased by exposure of the roots to a solution containing naphthalic anhydride. Increased imazethapyr metabolism due to naphthalic anhydride treatment of roots was observed within 4 h following safener exposure. Nitrogen, carbon monoxide and tetcyclacis inhibited imazethapyr metabolism in maize coleoptiles grown from naphthalic anhydride treated seed. This suggests that imazethapyr is metabolized by a cytochrome P-450 monooxygenase.Naphthalic anhydride application to maize seed increased the level of cytochrome P-450 in the seedling shoots. Microsomes isolated from coleoptiles grown from naphthalic anhydride treated seed, but not untreated seed, converted bentazon to hydroxy-bentazon but did not me tabolize imazethapyr. Protection of maize from imazethapyr damage by naphthalic anhydride is due to a safener-induced higher rate of imazethapyr metabolism associated with elevated cytochrome P-450 levels. However, this was not demonstrated in vitro for imazethapyr.

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Influence of Safeners on the in vivo and in vitro Metabolism of Bentazon and Metolachlor by Grain Sorghum Shoots: a Preliminary Report

Zeitschrift für Naturforschung C ◽

10.1515/znc-1991-9-1031 ◽

1991 ◽

Vol 46 (9-10) ◽

pp. 906-914 ◽

Cited By ~ 12

Author(s):

Donald E. Moreland ◽

Frederick T. Corbin

Keyword(s):

Grain Sorghum ◽

In Vitro Studies ◽

Naphthalic Anhydride ◽

Surface Sterilization ◽

Polar Components ◽

In Vitro Shoots ◽

Treated Seed ◽

Cytochrome P 450

Abstract Metabolism of bentazon and metolachlor by excised shoots and a microsomal fraction isolated from the shoots, of 3-day-old, dark-grown, grain sorghum (Sorghum bicolor cv. Funk G 522 DR) seedlings was studied. The effects of seed treatments, on the subsequent metabolism of the herbicides, with the safeners naphthalic anhydride, oxabetrinil, and CGA 133205 were compared against surface-sterilization and Captan-treatments. Bentazon was aryl hydroxylated in both in vivo and in vitro studies with the hydroxylated derivative undergoing glycosylation only under in vivo conditions. Both shoots and microsomes isolated from shoots of safener-treated seed showed enhanced metabolism of bentazon relative to the controls. In hibition by tetcyclacis, a potent inhibitor of plant cytochrome P-450 monooxygenases, in both the in vivo and in vitro studies, and a requirement for NADPH in the in vitro studies suggested that the formation of hydroxybentazon was mediated by a cytochrome P-450 monooxygenase. Metolachlor was metabolized to polar material and O-desmethylmetolachlor under in vivo conditions. Only the demethylated product was formed in vitro. Shoots isolated from safener-treated seed showed enhanced formation of polar com pounds which were assumed to have arisen from conjugation with glutathione. Tetcyclacis did not affect the formation of the polar components. However, the formation of O-desmethylmetolachlor was depressed in the shoots excised from safener-treated seed under both in vivo and in vitro conditions. Tetcyclacis completely prevented formation of the demethylated metabolite. Hence, formation of this metabolite is considered to be P-450 mediated. The differential response obtained with the safeners, i.e., stimulation of aryl hydroxylation of bentazon and depression of metolachlor demethylation, suggests that the reactions are probably catalyzed by different cytochrome P-450 monooxygenases.

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Nicosulfuron, primisulfuron, and bentazon hydroxylation by corn (Zea mays), woolly cupgrass (Eriochloa villosa), and shattercane (Sorghum bicolor) cytochrome P-450

Weed Science ◽

10.1017/s004317450008869x ◽

1997 ◽

Vol 45 (4) ◽

pp. 474-480 ◽

Cited By ~ 16

Author(s):

John R. R. Hinz ◽

Micheal D. K. Owen ◽

Michael Barrett

Keyword(s):

Herbicide Tolerance ◽

Untreated Seed ◽

Naphthalic Anhydride ◽

Whole Plant ◽

Woolly Cupgrass ◽

Species Tolerance ◽

Eriochloa Villosa ◽

Cytochrome P 450

Microsomes (100,000 g pellet containing mixed membrane fractions but primarily endoplasmic reticulum) were isolated from shoots of corn, shattercane, and woolly cupgrass grown from naphthalic anhydride treated or untreated seed to determine if metabolism of bentazon, nicosulfuron, and primisulfuron could be demonstrated in the preparations. Corn is tolerant of all three herbicides, shattercane is tolerant of bentazon, and woolly cupgrass is tolerant of bentazon and primisulfuron. Naphthalic anhydride treatment was required for detectable bentazon, nicosulfuron, and primisulfuron hydroxylation in corn microsomes and for bentazon hydroxylation in woolly cupgrass microsomes. Bentazon hydroxylation was low, but detectable, in microsomes from shattercane shoots without naphthalic anhydride treatment. Naphthalic anhydride-treated corn microsomes hydroxylated 292, 120, and 52 pmol mg−1protein min−1of bentazon, nicosulfuron, and primisulfuron, respectively. Primisulfuron (19 pmol mg−1protein min−1), but not nicosulfuron, was hydroxylated in woolly cupgrass microsomes. Neither nicosulfuron nor primisulfuron was hydroxylated in shattercane microsomes. Bentazon and primisulfuron inhibited nicosulfuron hydroxylation in corn microsomes. Bentazon, but not nicosulfuron, also inhibited primisulfuron hydroxylation in the corn microsomes. This indicates that the three herbicides can interact at the same cytochrome P-450(s) in corn. Primisulfuron hydroxylation was not inhibited by either bentazon or nicosulfuron in woolly cupgrass microsomes. This suggests that the cytochrome P-450(s) for primisulfuron hydroxylation are different between corn and woolly cupgrass. Also, bentazon hydroxylation in corn and shattercane microsomes was inhibited by the cytochrome P-450 inhibitor tetcyclasis, while that in woolly cupgrass was not. Again, this suggests a difference in the cytochrome P-450(s) responsible for bentazon metabolism among the species. Although absolute conclusions comparing in vitro microsomal activities to whole plant herbicide tolerance cannot be made because it is unknown whether the same cytochrome P-450(s) are studied in microsomes from naphthalic anhydride-treated tissue as are responsible for in vivo herbicide metabolism, there was a broad correlation between metabolism of a particular herbicide in microsomes of a species and the species' tolerance of that herbicide.

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Oxygenation of 18-hydroxycorticosterone as the final reaction for aldosterone biosynthesis

Acta Endocrinologica ◽

10.1530/acta.0.1070395 ◽

1984 ◽

Vol 107 (3) ◽

pp. 395-400 ◽

Cited By ~ 9

Author(s):

Itaru Kojima ◽

Etsuro Ogata ◽

Hiroshi Inano ◽

Bun-ichi Tamaoki

Keyword(s):

Carbon Monoxide ◽

Hydroxysteroid Dehydrogenase ◽

Dependent Manner ◽

In Vitro Production ◽

Mitochondrial Preparation ◽

Final Reaction ◽

Vitro Production ◽

Dose Dependent ◽

Cytochrome P 450

Abstract. Incubation of 18-hydroxycorticosterone with the sonicated mitochondrial preparation of bovine adrenal glomerulosa tissue leads to the production of aldosterone, as measured by radioimmunoassay. The in vitro production of aldosterone from 18-hydroxycorticosterone requires both molecular oxygen and NADPH, and is inhibited by carbon monoxide. Cytochrome P-450 inhibitors such as metyrapone, SU 8000. SU 10603, SKF 525A, amphenone B and spironolactone decrease the biosynthesis of aldosterone from 18-hydroxycorticosterone. These results support the conclusion that the final reaction in aldosterone synthesis from 18-hydroxycorticosterone is catalyzed by an oxygenase, but not by 18-hydroxysteroid dehydrogenase. By the same preparation, the production of [3H]aldosterone but not [3H]18-hydroxycorticosterone from [1,2-3H ]corticosterone is decreased in a dose-dependent manner by addition of non-radioactive 18-hydroxycorticosterone.

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Safeners as Corn Seedling Protectants against Acetolactate Synthase Inhibitors

Zeitschrift für Naturforschung C ◽

10.1515/znc-1991-11-1203 ◽

1991 ◽

Vol 46 (11-12) ◽

pp. 945-949

Author(s):

Henri Milhomme ◽

Christophe Roux ◽

Jean Bastide

Keyword(s):

Zea Mays ◽

Zea Mays L ◽

Acetolactate Synthase ◽

Large Degree ◽

Naphthalic Anhydride ◽

Metsulfuron Methyl ◽

Corn Seedling

Zea mays L., cv. Potro, shoots had a higher level of resistance to imazaquin (IQ) and metsulfuron methyl (M SM ) than roots. Shoot lengths were increased by pretreating the seeds with commercial 1,8 -naphthalic anhydride (N A ) at 1% (w/w) or oxabetrinil at 0.2% (w/w). The growth of shoots of safened seeds was unaffected by 400 nM IQ and by 40 nM MSM. The in vivo activity of acetolactate synthase (ALS) extracted from corn shoots and roots was not affected by treatments with IQ or MSM, but pretreatment of seeds with NA or oxabetrinil, prior to germination, caused an increase in the level of extractable ALS from shoots. ALS activity from roots and shoots of NA-pretreated seedlings was increased to a large degree (> 40% ) when the seedlings were germinated on 40 nM MSM, whereas ALS activities from oxabetrinil-pretreated seedlings were enhanced to a lesser degree (≈20%). ALS from unsafened seedlings was inhibited 21% by 400 nM IQ and 70% by 40 nM MSM in vitro, but ALS from roots of seedlings germinated on 400 nM IQ was not inhibited by 400 nM IQ in vitro.

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The characteristics of the microsomal hydroxylation of tolbutamide

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y91-061 ◽

1991 ◽

Vol 69 (3) ◽

pp. 400-405 ◽

Cited By ~ 8

Author(s):

Pierre M. Bélanger ◽

Serge St-Hilaire

Keyword(s):

Carbon Monoxide ◽

Liver Microsomes ◽

Hepatic Metabolism ◽

Species Variation ◽

Rat Liver Microsomes ◽

Hydroxylase Activity ◽

Microsomal Metabolism ◽

Microsomal Hydroxylation ◽

Cytochrome P 450

The in vitro metabolism of tolbutamide to the hydroxymethyl derivative was studied using hepatic microsomal homogenates. The hydroxymethyl metabolite was quantitated by HPLC. The hepatic microsomal hydroxylase was completely inhibited by carbon monoxide and was NADPH dependent. Metyrapone, α-naphthoflavone, phenelzine, mercuric chloride, and nitrogen significantly inhibited the reaction indicating the involvement of the cytochrome P-450 monooxygenase. Species variation showed that the order of hepatic microsomal activity was rat > rabbit >> guinea pig >> mouse and hamster. The reaction increased with time up to 40 min and followed Michaelis–Menten kinetics in rat liver microsomes with apparent Km and Vmax values of 224.4 μM and 359.9 pmol∙mg−1∙min−1, respectively. The reaction was induced by phenobarbital but was depressed after pretreatment with 3-methylcholanthrene and isosafrole. However, expression of the hydroxylase activity per nanomoles of cytochrome P-450 showed that the activity was much higher in liver microsomes of isosafrole pretreated rats. These results indicate the involvement of different isozymes of cytochrome P-450 in the microsomal hydroxylation of tolbutamide.Key words: tolbutamide metabolism, tolbutamide hydroxylation, microsomal hydroxylation, microsomal metabolism of tolbutamide, hepatic metabolism of tolbutamide.

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EFFECTS OF THE HERBICIDE SAFENER NAPHTHALIC ANHYDRIDE ON THE GROWTH OF A ZEA MAYS L. CELL SUSPENSION CULTURE: INTERACTION WITH THE HERBICIDE METSULFURON-METHYL AND 2,4-D

Herbicide Resistance in Weeds and Crops ◽

10.1016/b978-0-7506-1101-5.50058-9 ◽

1991 ◽

pp. 466-467

Author(s):

N.D. Polge ◽

A.D. Dodge ◽

J.C. Caseley

Keyword(s):

Zea Mays ◽

Suspension Culture ◽

Cell Suspension ◽

Cell Suspension Culture ◽

Zea Mays L ◽

Naphthalic Anhydride ◽

Metsulfuron Methyl ◽

Herbicide Safener ◽

L Cell

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Safeners as Corn Seedling Protectants against Acetolactate Synthase Inhibitors

Zeitschrift für Naturforschung C ◽

10.1515/znc-1991-9-1038 ◽

1991 ◽

Vol 46 (9-10) ◽

pp. 945-949 ◽

Cited By ~ 3

Author(s):

Henri Milhomme ◽

Christophe Roux ◽

Jean Bastide

Keyword(s):

Zea Mays ◽

Zea Mays L ◽

Acetolactate Synthase ◽

Large Degree ◽

Naphthalic Anhydride ◽

Corn Seedling

Abstract Zea mays L., cv. Potro, shoots had a higher level of resistance to imazaquin (IQ) and metsulfuron methyl (MSM) than roots. Shoot lengths were increased by pretreating the seeds with commercial 1,8-naphthalic anhydride (NA) at 1% (w/w) or oxabetrinil at 0.2% (w/w). The growth of shoots of safened seeds was unaffected by 400 nᴍ IQ and by 40 nᴍ MSM.The in vivo activity of acetolactate synthase (ALS) extracted from corn shoots and roots was not affected by treatments with IQ or MSM , but pretreatment of seeds with NA or oxabetrinil, prior to germination, caused an increase in the level of extractable ALS from shoots. ALS activity from roots and shoots of NA-pretreated seedlings was increased to a large degree (> 40 %) when the seedlings were germinated on 40 nᴍ MSM , whereas ALS activities from oxabetrinil-pretreated seedlings were enhanced to a lesser degree (≈20%). ALS from unsafened seedlings was inhibited 21% by 400 nᴍ IQ and 70% by 40 nᴍ MSM in vitro, but ALS from roots of seedlings germinated on 400 nᴍ IQ was not inhibited by 400 nᴍ IQ in vitro.

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In Vitro Germination and Dormancy Responses of Hydrangea macrophylla and Hydrangea paniculata Seeds to Ethyl Methane Sulfonate and Cold Treatment

HortScience ◽

10.21273/hortsci.44.3.764 ◽

2009 ◽

Vol 44 (3) ◽

pp. 764-769 ◽

Cited By ~ 3

Author(s):

Stephen Patrick Greer ◽

Timothy A. Rinehart

Keyword(s):

Cold Treatment ◽

In Vitro Germination ◽

Ethyl Methane Sulfonate ◽

Optimal Conditions ◽

Methane Sulfonate ◽

Untreated Seed ◽

Ethyl Methane ◽

Hydrangea Macrophylla ◽

Treated Seed

To determine the optimal conditions for mutagenesis of Hydrangea macrophylla (Thunb.) Ser. and Hydrangea paniculata Siebold, cold-treated and untreated seed from representative cultivars were exposed to 0.5%, 2.5%, and 5.0% ethyl methane sulfonate (EMS). Most untreated H. macrophylla seed exposed to 2.5% and 5.0% EMS had substantially lower germination percentages. H. paniculata seed germination percentages did not differ from controls until EMS concentrations reached 5.0%. Cold treatment of H. macrophylla and H. paniculata seed made germination more tolerant to all concentrations of EMS tested and increased germination of most H. macrophylla cultivars when compared with lower dosages. Germination of cold-treated seed from H. paniculata cultivars rose substantially above control levels even at the highest dosages. For the most part, we observed more nondormant seed, or seed available for germination, but less viability with increasing EMS dosage in untreated Hydrangea L. seed versus controls. In contrast, cold-treated seed displayed higher levels of mutagen tolerance and nondormancy versus controls when exposed to these same doses of EMS.

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