THE ENZYMICALLY CATALYZED OXIDATION OF INDOLEACETIC ACID

1956 ◽  
Vol 34 (6) ◽  
pp. 905-926 ◽  
Author(s):  
E. R. Waygood ◽  
Ann Oaks ◽  
G. A. Maclachlan
Keyword(s):  
Indoleacetic Acid ◽  
Maleic Hydrazide ◽  
Organic Peroxide ◽  
Horse Radish Peroxidase ◽  
Reaction Sequence ◽  
Leaf Extracts ◽  
Naturally Occurring ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Catalyzed Oxidation

Dialyzed wheat leaf extracts, catalase, and horse-radish peroxidase catalyze the decarboxylation and oxidation of indoleacetic acid at pH 5.0–6.0 in the presence of critical concentrations of manganese and monohydric phenols or resorcinol. The equivalent of 1 mole of carbon dioxide is liberated and 1 mole of oxygen consumed per mole of substrate. Manganic ions formed by a phenol–peroxidase–peroxide system initiate the decarboxylation and oxidation. A naturally occurring ether soluble factor from wheat leaves, and maleic hydrazide, can substitute for the active phenols. Catechol, hydroquinone, pyrogallol, seopoletin, and riboflavin, etc. competitively inhibit the oxidation. The nature of the active peroxide is discussed and a reaction sequence involving an organic peroxide or radical rather than hydrogen peroxide is submitted as being a possibility.

QUALITATIVE AND QUANTITATIVE DETERMINATION OF THE WHEAT LEAF CARBOHYDRATES

1950 ◽  
Vol 28c (6) ◽  
pp. 754-779 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Reducing Sugars ◽  
Degradation Products ◽  
Reducing Power ◽  
Insoluble Residue ◽  
Leaf Extracts ◽  
Wheat Leaf ◽  
Leaf Carbohydrates ◽  
Wheat Leaves ◽  
Reducing Substances ◽  
Fructose Determination

The nonreducing sugar in wheat leaves is probably entirely sucrose. It is the only abundant sugar. Free reducing sugars are absent, or almost absent from wheat leaves grown under the conditions described. The reducing power in the cleared alcoholic extracts of the leaves is, at least, partly due to degradation products of ascorbic acid. Other nonsugar reducing substances also are apparently present. The alcohol insoluble residue from wheat leaves contains little or no fructosan, dextrin, or starch at the two and one-half week old stage. Satisfactory methods for extracting and determining the sucrose are described. The following methods gave satisfactory results with wheat leaf extracts: the reducing power methods of Hanes and Somogyi after acid or preferably invertase hydrolysis, Ost's solution for fructose residues, the method of Neuberg and Strauss, the colorimetric resorcinol method. The latter method gives only approximate values for fructose residues unless the sugar concentration is high; the method is then fairly reliable. The following methods did not give satisfactory results: Hanes and Somogyi methods for free reducing sugars initially present in the extract, the hypoiodite titration for aldose sugars, and Sieben's method for fructose determination.

KINETICS OF THE ENZYMICALLY-CATALYZED OXIDATION OF INDOLEACETIC ACID

1956 ◽  
Vol 34 (1) ◽  
pp. 1233-1250 ◽  
Author(s):  
G. A. Maclachlan ◽  
E. R. Waygood
Keyword(s):  
Indoleacetic Acid ◽  
Aryl Radical ◽  
Reaction Sequence ◽  
Final Reaction Product ◽  
Final Reaction ◽  
A Chain ◽  
Kinetics Of ◽  
Catalyzed Oxidation

A study of the kinetics of the enzymically-catalyzed decarboxylation and oxidation of indoleacetic acid has provided evidence that it is a chain autoxidation initiated and propagated by two enzyme-controlled peroxidations. The following reaction sequence occurs:[Formula: see text]where S—COOH = indoleacetic acid; S∙ = skatole radical; SO2∙ = oxidized skatole radical or indole peroxide; SO2H = final reaction product; ROH = phenolic cofactor, i.e., resorcinol; RO∙ = semiquinol or aryl radical.

ON THE MECHANISM OF INDOLEACETIC ACID OXIDATION BY WHEAT LEAF ENZYMES

1956 ◽  
Vol 34 (1) ◽  
pp. 54-59 ◽  
Author(s):  
E. R. Waygood ◽  
Ann Oaks ◽  
G. A. Maclachlan
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Induction Period ◽  
Indoleacetic Acid ◽  
Acid Oxidation ◽  
Not Given ◽  
Carbon Dioxide Evolution ◽  
Enzyme Preparations ◽  
Wheat Leaf ◽  
Wheat Leaves

Partially purified enzyme preparations of wheat leaves oxidize indoleacetic acid completely in the presence of manganese and a monohydroxyphenol or resorcinol. A characteristic feature of the oxygen uptake is an induction period followed by a rapid oxygen uptake which ceases when 1 mole of oxygen is consumed per mole indoleacetic acid added. One mole of carbon dioxide is evolved per mole indoleacetic acid. There is no lag in carbon dioxide evolution, but it is not given off anaerobically. Oxygen, blue light, and acetaldehyde overcome the induction period. Hydrogen peroxide formed in a final aerobic dehydrogenase step is utilized to provide a source of manganic ions which act as an electron acceptor in an initial oxidative step.

KINETICS OF THE ENZYMICALLY-CATALYZED OXIDATION OF INDOLEACETIC ACID

1956 ◽  
Vol 34 (6) ◽  
pp. 1233-1250 ◽  
Author(s):  
G. A. Maclachlan ◽  
E. R. Waygood
Keyword(s):  
Indoleacetic Acid ◽  
Aryl Radical ◽  
Reaction Sequence ◽  
Final Reaction Product ◽  
Final Reaction ◽  
A Chain ◽  
Kinetics Of ◽  
Catalyzed Oxidation

A study of the kinetics of the enzymically-catalyzed decarboxylation and oxidation of indoleacetic acid has provided evidence that it is a chain autoxidation initiated and propagated by two enzyme-controlled peroxidations. The following reaction sequence occurs:[Formula: see text]where S—COOH = indoleacetic acid; S∙ = skatole radical; SO2∙ = oxidized skatole radical or indole peroxide; SO2H = final reaction product; ROH = phenolic cofactor, i.e., resorcinol; RO∙ = semiquinol or aryl radical.

THE ISOLATION AND IDENTIFICATION OF SUCROSE FROM THE SEEDLING WHEAT LEAF

1953 ◽  
Vol 31 (1) ◽  
pp. 75-80 ◽  
Author(s):  
G. M. Ward
Keyword(s):  
Chromatographic Analysis ◽  
Soluble Sugar ◽  
Analytical Techniques ◽  
Barium Salt ◽  
X Ray Diffraction ◽  
Leaf Extracts ◽  
Isolation And Identification ◽  
X Ray ◽  
Wheat Leaf ◽  
Wheat Leaves

Crystalline sucrose has been isolated from cleared alcoholic extracts of mature wheat leaves by precipitation as the barium salt. The crystals were positively identified by melting point, X-ray diffraction analysis, and glucose–fructose ratio as well as by conventional analytical techniques. The evidence for the presence of sucrose in the wheat leaf has been corroborated by chromatographic analysis of leaf extracts. It is concluded that sucrose forms the bulk of the soluble sugar reserve of this tissue.

scholarly journals Plant protein phosphatases. Subcellular distribution, detection of protein phosphatase 2C and identification of protein phosphatase 2A as the major quinate dehydrogenase phosphatase

1991 ◽  
Vol 273 (3) ◽  
pp. 733-738 ◽  
Author(s):  
C MacKintosh ◽  
J Coggins ◽  
P Cohen
Keyword(s):  
Oilseed Rape ◽  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Soluble Fraction ◽  
Protein Phosphatases ◽  
Leaf Extracts ◽  
Carrot Cells ◽  
Rapid Inactivation ◽  
Wheat Leaf ◽  
Wheat Leaves

Protein phosphatases 1 and 2A (PP1 and PP2A) were identified in a variety of plant cells and found to be particulate or soluble depending on the species. In extracts prepared from oilseed-rape seeds these enzymes were associated with microsomes and more rapidly sedimenting fractions, whereas in wheat leaf extracts they were largely microsomal, the remainder being present in the soluble fraction. In pea leaf and carrot cell extracts PP1 and PP2A were almost entirely soluble. No PP1 or PP2A activity was associated with the membranes or stroma of chloroplasts in oilseed-rape seeds, pea leaves and wheat leaves. An Mg2(+)-dependent okadaic acid-insensitive protein phosphatase that resembles protein phosphatase 2C (PP2C) was detected in carrot cells, pea leaves and wheat leaves, but not in oilseed-rape seeds. In wheat leaf extracts PP2C was mostly present in the soluble fraction, a different location from PP1 or PP2A. The rapid inactivation of the cytosolic enzyme quinate dehydrogenase (QDH) in a fraction prepared from light-grown carrot cells was completely blocked by either okadaic acid or microcystin (two potent and specific inhibitors of PP1 and PP2A), whereas inhibitor 2 (a specific inhibitor of PP1) inhibited inactivation by only about 10%. Addition of the purified PP2A catalytic subunit from mammalian skeletal muscle increased the rate of QDH inactivation, whereas addition of mammalian PP1 did not. It is concluded that PP2A is the major enzyme responsible for dephosphorylating (inactivating) QDH in carrot cells. These observations indicate that okadaic acid and microcystin may be useful for identifying other plant processes that are controlled by phosphorylation/dephosphorylation mechanisms. Okadaic acid did not prevent the rapid inactivation of phosphoribulokinase or activation of glucose-6-phosphate dehydrogenase in a fraction prepared from light-grown pea leaves, and addition of the purified catalytic subunits of PP1 and PP2A did not accelerate either process. These observations, in conjunction with the absence of PP1 and PP2A activity in chloroplasts, suggest that these phosphatases are not involved in the regulation of chloroplast metabolism.

scholarly journals Association of Pestalotiopsis Guepinii (DESM.) Stay. with Bipolaris Leaf Blight (BpLB) Infected Wheat Leaves-A new Record

2016 ◽  
Vol 40 (1) ◽  
pp. 87-90
Author(s):  
Shamim Shamsi ◽  
Mst Selina Momtaz
Keyword(s):  
New Record ◽  
Leaf Blight ◽  
Wheat Varieties ◽  
Anamorphic Fungus ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Academy Of Sciences

Pestalotiopsis guepinii (Desm.) Stay an anamorphic fungus belonging to the class Celomycetes was isolated from Bipolaris leaf blight (BpLB) infected wheat leaf of two wheat varieties namely, Balaka and Saurab during the period of February to March, 2011. Association of Pestalotiopsis guepinii with wheat is a new record.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 1, 87-90, 2016

Increased Lipoxygenase Activity is Involved in the Hypersensitive Response of Wheat Leaf Cells Infected with A virulent Rust Fungi or Treated with Fungal Elicitor

1986 ◽  
Vol 41 (5-6) ◽  
pp. 559-563 ◽  
Author(s):  
Carlos A. Ocampo ◽  
Bruno Moerschbacher ◽  
Hans J. Grambow
Keyword(s):  
Hypersensitive Response ◽  
Hypersensitive Reaction ◽  
Rust Fungi ◽  
Lipoxygenase Activity ◽  
Puccinia Graminis ◽  
Compatible Interaction ◽  
Wheat Leaf ◽  
Wheat Leaves ◽  
Germ Tubes ◽  
Wheat Rust

The hypersensitive reaction in incompatible wheat-rust interactions is characterized by an increase in lipoxygenase activity detectable as early as 28 h after penetration of the pathogen. In contrast, lipoxygenase activity in the compatible interaction did not increase until the onset of sporulation.Lipoxygenase activity also increased following treatment of wheat leaves with an elicitor fraction from germ tubes of Puccinia graminis tritici.

scholarly journals Analysis of Draft Genome Sequences of Two New Pantoea Strains Associated with Wheat Leaf Necrotic Tissues Caused by Xanthomonas translucens Reveals Distinct Species

2020 ◽  
Vol 9 (30) ◽  
Author(s):  
Alexandre Malette ◽  
Renlin Xu ◽  
Suzanne Gerdis ◽  
Sylvia I. Chi ◽  
Greg C. Daniels ◽  
...  
Keyword(s):  
Draft Genome ◽  
Distinct Species ◽  
Whole Genome ◽  
Genome Sequences ◽  
Coding Sequences ◽  
Content Type ◽  
Wheat Leaf ◽  
Xanthomonas Translucens ◽  
Wheat Leaves

ABSTRACT We report whole-genome sequences of two new Pantoea strains (DOAB1048 and DOAB1050) isolated from necrotic wheat leaves caused by Xanthomonas translucens. The draft genome sequences of DOAB1048 and DOAB1050 consist of 52 and 57 scaffolds and have sizes of 4,795,525 bp and 4,962,883 bp with 4,418 and 4,517 coding sequences, respectively.

scholarly journals Presence of ice-nucleating Pseudomonas on wheat leaves promotes Septoria tritici blotch disease (Zymoseptoria tritici) via a mutually beneficial interaction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Helen N. Fones
Keyword(s):  
Frost Damage ◽  
Ice Nucleation ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Zymoseptoria Tritici ◽  
Bacterial Populations ◽  
Wheat Leaf ◽  
Ina Bacteria ◽  
Wheat Leaves ◽  
Important Disease

Abstract Zymoseptoria tritici causes Septoria tritici blotch (STB) of wheat, an economically important disease causing yield losses of up to 10% despite the use of fungicides and resistant cultivars. Z. tritici infection is symptomless for around 10 days, during which time the fungus grows randomly across the leaf surface prior to entry through stomata. Wounded leaves show faster, more extensive STB, suggesting that wounds facilitate fungal entry. Wheat leaves also host epiphytic bacteria; these include ice-nucleating (INA+) bacteria, which induce frost damage at warmer temperatures than it otherwise occurs. Here, STB is shown to be more rapid and severe when wheat is exposed to both INA+ bacteria and sub-zero temperatures. This suggests that ice-nucleation-induced wounding of the wheat leaf provides additional openings for fungal entry. INA+ bacterial populations are shown to benefit from the presence of Z. tritici, indicating that this microbial interaction is mutualistic. Finally, control of INA+ bacteria is shown to reduce STB.

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