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PubMed1987

Simultaneous liquid chromatographic determination of vanillylmandelic acid, homovanillic acid, and 5-hydroxy-3-indoleacetic acid in urine, using isocratic elution and electrochemical detection.

A method for the simultaneous measurement of vanillylmandelic acid, homovanillic acid and 5-hydroxyindoleacetic acid in urine is described. Based on reversed-phase liquid chromatography with electrochemical detection, the procedure employs isocratic elution, thus making it suitable for use in the less well-equipped clinical or research laboratory. A simple extraction of the acids from acidified urine into ethyl acetate, is followed by evaporating to dryness a portion of the organic layer, and redissolving the residue in chromatographic mobile phase. Up to 20 samples can be analysed in a single working day. The method is validated and the results obtained are compared with reference methods. The cause of contamination of the glassy carbon surface of the working electrode is investigated, and a simple electrochemical pretreatment is described that overcomes this problem. Finally, the extra clinical information that can be derived from multi-metabolite assays is considered.

Biogenic Amines↗
PubMed1984

Cerebrospinal fluid homovanillic acid and 5-hydroxy-indoleacetic acid in adults with attention deficit disorder, residual type.

Following the hypothesis that attention deficit disorder in adults (attention deficit disorder, residual type; ADD, RT), as well as in children, is associated with decreased central dopaminergic activity, the authors measured lumbar cerebrospinal fluid monoamine metabolites in a group of adults with ADD, RT and matched control subjects. Patients were then entered into a double-blind, placebo-controlled trial of methylphenidate. It was predicted that the patients would have lower levels of homovanillic acid (HVA), the major dopamine metabolite in humans. Patients who had a significant response to methylphenidate showed a trend in this direction. Nonresponding patients had significantly higher levels of HVA than controls.

Adult↗
PubMed1977

Importance of Time after Excision and of pH on the Kinetics of Response of Wheat Coleoptile Segments to Added Indoleacetic Acid.

Segments of coleoptiles of 3-day-old wheat (Triticum x Aestivum L. cv. Kharkov M.C. 22) grown at 24 C were strung on a glass rod and the kinetics of their elongation in 0.01 m K-phosphate buffer was examined photometrically. Measured rates of elongation in response to treatments were corrected by subtraction of endogenous rates. The customary practice of testing the effects of growth regulators added between the two endogenous surges of growth, that is, up to 3 hours after segments were excised from coleoptiles, gave erroneous kinetic data. Rates of response were then limited by the passive penetration of added auxin and the second endogenous surge interfered with late responses. It was necessary to wait for a phase of more rapid but more steady elongation after the second endogenous surge was over, about 4 hours for wheat at 25 C, to attain the active uptake required for nearly synchronous response through the segment. The more active uptake in this steady phase was confirmed with beta-[2-(14)C]indoleacetic acid and it was greater at pH 5 than at pH 7. The degree of dissociation of indoleacetic acid added at pH 7 was an impediment to penetration that could be compensated for by removal of intercellular air. The pH did not influence the endogenous rate of elongation. The dependence of the rate of elongation on the concentration of indoleacetic acid added at pH 5 was bell-shaped with maximum rate at 10 mum indoleacetic acid, in confirmation of previous measurements made over long intervals of time. The relation between the response and suboptimal concentrations was not sigmoid but was indicative of greater binding affinity than previously reported.

Journal Article↗
PubMed1990

Indoleacetic acid operon of Pseudomonas syringae subsp. savastanoi: transcription analysis and promoter identification.

Expression of the indoleacetic acid (iaa) operon, which contributes to the virulence of the phytopathogenic bacterium Pseudomonas syringae subsp. savastanoi, was monitored by using broad-host-range lacZ reporter gene plasmids. A combination of translational (gene) fusions and transcriptional (operon) fusions of P. syringae subsp. savastanoi sequences to lacZ allowed localization of the iaa operon promoter. RNA recovered from P. syringae subsp. savastanoi strains was mapped with iaa operon-specific probes to precisely locate the transcription initiation site. When transcripts from an iaaM::lacZ fusion in Escherichia coli were analyzed, an identical transcription initiation site was observed. The DNA sequence of the iaa operon promoter closely resembled the consensus E. coli promoter sequence. We detected an active, constitutive level of indoleacetic acid biosynthetic gene expression during bacterial growth under a variety of conditions in the absence of host plant influence.

Base Sequence↗
PubMed1966

Movement of indoleacetic acid in coleoptiles of Avena sativa L. II. Suspension of polarity by total inhibition of the basipetal transport.

Acropetal and basipetal movement of indole-3-acetic acid through coleoptiles of Avena sativa L. was studied. Sections 10-mm long were supplied with either apical or basal sources containing C(14) carboxyl-labeled indoleacetic acid (10(-5)m). Anaerobic conditions inhibit metabolically dependent movement (transport) thus reducing basipetal but not acropetal movement. Total inhibition of basipetal transport abolishes the polarity of auxin uptake and movement. The nonpolar movement that remains in anaerobic sections is free diffusion with an average diffusion coefficient of approximately 1 x 10(-4) mm(2) per second. During an 8-hour diffusion, at least the first millimeter of the section comes to equilibrium at approximately the same concentration as the donor.Acropetal movement is probably by diffusion and is accompanied by an aerobic immobilization of indoleacetic acid that increases more than proportionally to concentration. Anaerobic conditions totally prevent this immobilization and reduce acropetal uptake but not the amount of indoleacetic acid moving into the upper parts of the section; there is, therefore, no evidence for acropetal transport. Polarity of auxin movement in aerobic coleoptile sections is achieved by strict basipetal transport of auxin. The basipetal transport may intensify the polarity by recycling auxin that is moving acropetally.

Biological Transport↗
PubMed1982

Evidence of singlet oxygen participation in the chlorophyll-sensitized photooxidation of indoleacetic Acid.

Chlorophyll-sensitized photooxidation of indoleacetic acid (IAA)-with chlorophyll extracted from Pisum sativum L. cv. Alaska W.R.-was determined in the presence of deuterium oxide and known quenchers of singlet oxygen ((1)O(2)) to explore the involvement of (1)O(2) in the reaction. O(2) uptake was measured in light in a buffered aqueous micellar system containing Triton X-100, KCl, chlorophyll, and IAA. The rate of O(2) uptake was zero in darkness. The reaction was stimulated by deuterium oxide and inhibited by sodium azide indicating that (1)O(2) participated in IAA photooxidation. Both mannitol and superoxide dismutase failed to inhibit O(2) uptake suggesting that neither the hydroxyl radical nor the superoxide anion played a significant role in the reaction.

Journal Article↗
PubMed1967

Indoleacetic acid oxidase activity of apoperoxidase.

The conventional activity of electrophoretically purified horseradish peroxidase toward guaiacol, pyrogallol, 2,6-dimethoxyphenol, and benzidine is abolished by removal of the heme prosthetic group with a mixture of cold acetone and hydrogen chloride. The apoenzyme, though devoid of peroxidase activity, retains its activity as an indoleacetic acid oxidase when it is supplied with 10(-5) mole of manganous ion and 2,4-dachlorophenol per liter. This oxidase activity is cyanide-sensitive; azide also inhibits under specific conditions of both pH and cofactor concentration. Partial restoration of the peroxidase activity by recombination of apoprotein with heme produces no effect on the oxidase activity, except that cofactors are no longer absolutely required. Therefore, it appears that the activity of peroxidase as an indoleacetic acid oxidase need not directly involve the heme prosthetic group, or that manganous ions and dichlorophenol can substitute for the heme group in the reaction between indoleacetic acid and oxidase.

Azides↗
PubMed2002

Ionic strength has a greater effect than does transmembrane electric potential difference on permeation of tryptamine and indoleacetic acid across Caco-2 cells.

The effects of transmembrane electric potential difference and ionic strength on the permeation of tryptamine and indoleacetic acid across a Caco-2 cell monolayer were examined. A decrease in the transmembrane electric potential difference caused by the addition of potassium ion to the transport buffer had no effect on the permeation rate of either compound. On the other hand, an increase in ionic strength resulted in a decrease in the permeation rate of tryptamine and an increase in the permeation rate of indoleacetic acid. The changes in the permeation rate with changes in the ionic strength were correlated with the membrane surface potential monitored by 1-anilino-8-naphthalenesulfonic acid (ANS), a fluorescent probe. We tested these effects using several other cationic and anionic compounds. These effects of ionic strength were found to be common to all drugs tested. The compound that showed a relatively lower permeation rate was given relatively stronger effect. The possibility of overestimation or underestimation caused by these effects should be considered when the permeation of an ionic compound is evaluated using a cell monolayer system.

Anilino Naphthalenesulfonates↗
PubMed1975

Rapid effects of indoleacetic Acid and ethylene on the growth of intact pea roots.

Root auxanometers were used to determine the growth rates of individual intact primary roots accurately and quickly. The growth of pea (Pisum sativum L.) roots was inhibited by both indoleacetic acid and ethylene within 20 minutes. A supramaximal concentration of ethylene inhibited root growth less than did 5 to 20 mum indoleacetic acid, indicating that inhibition of root growth by auxin was not due only to indoleacetic acid-induced ethylene production. Inhibition of root growth was largely relieved within 60 minutes of removal of both growth regulators.

Journal Article↗
PubMed1977

Polarity of Indoleacetic Acid in young Coleus Stems.

Young internodes of Coleus blumei Benth. have long been known for their sizable amount of acropetal indoleacetic acid movement. However, plants of the same clone, under improved growing conditions, now show almost absolute basipetal polarity of (14)C-indoleacetic acid, as measured by liquid scintillation counting of (14)C in the receiver cylinders of agar. The ratio of basipetal to acropetal movement is now as much as 85:1, instead of the 3:1 ratio found years ago under conditions providing slower growth.

Journal Article↗
PubMed1989

Correlation between Root-Generated Ionic Currents, pH, Fusicoccin, Indoleacetic Acid, and Growth of the Primary Root of Zea mays.

Correlations between root-generated ionic currents, extracellular pH, indoleacetic acid, fusicoccin, and growth were investigated. Current consistently entered the meristematic and elongating tissues of intact growing roots of Zea mays cv Golden Bantam. Mature root regions generated the outward limb of the current loop. Ion-substitution and pH-profile experiments suggested that the bulk of the ionic current was carried by H(+). Calcium ions did not carry current, but calcium may regulate the proton circulation since the proton current density was slightly larger in calcium-depleted media. Increased root elongation at low pH was associated with increased current density and an extended zone of inward current. Conversely decreased elongation at high pH was associated with a reduced current density and a more restricted zone of inward current. The effect of the fungal toxin fusicoccin was to increase the current density of the inward limb of the ion current and to increase root extension. Concentrations of indoleacetic acid that reduced root growth, also reduced the density of the inward current and shortened the inward current zone. The results emphasize the point that roots are electrically contiguous over many millimeters and that the electrophysiology of root growth is best studied in intact root systems.

Journal Article↗
PubMed1983

[A rapid method for determining urinary indoleacetic acid concentration and its clinical significance as the tumor-marker in the diagnosis of malignant diseases].

A rapid method for determining urinary indole-3-acetic acid (IAA) is introduced as the tumor-marker for the screening and diagnostic purpose of cancer patients by means of high performance liquid chromatography (HPLC). Its clinical significance is discussed along with a review of literatures. The IAA concentration and creatinine level of optionally collected urine samples were measured and used for the calculation of IAA amount per unit creatinine (microgram IAA/mg creatinine) in urine. Thus, an amount of 24-hours urinary IAA could be calculated without collecting a whole day's urine supply. Analysis of urinary IAA was performed within 10 minutes by HPLC. Urinary IAA level is usually high in the patients with the upper G-I tract cancers such as gastric cancer, esophageal cancer and hepato-biliary tract cancer, and also malignant hematopoietic disorders. But it is also high in non-cancer patients such as liver cirrhosis, diabetes mellitus and cholelithiasis occasionally. The patients with high urinary IAA level also showed high urinary levels of 5-hydroxy indoleacetic acid (5-HIAA) and monoamine oxidase activity (MAO). It was characteristic that hepatocellular carcinoma showed slight elevation of urinary IAA with normal levels of 5-HIAA and MAO. It is conclusive that the positive rate of elevated urinary IAA level was high in the patients with gastric cancer with ulcer-forming type in its morphological classification, and its level tends to elevate as the disease progresses. Therefore, the measurement of urinary IAA level in an optionally collected urine sample, as the tumor-marker, can be useful to check the progression and regression of gastric cancer.

Chromatography, High Pressure Liquid↗
PubMed1980

Metabolite gene regulation of the L-arabinose operon in Escherichia coli with indoleacetic acid and other indole derivatives.

The ability of indole derivatives to facilitate RNA polymerase transcription of the L-arabinose operon in Escherichia coli was shown to require the catabolite activator protein (CAP) as well as the araC gene product. Adenosine 3',5'-monophosphate (cAMP) was not obligatory for araBAD transcription when the cells were grown in the presence of 1 mM indole-3-acetic acid or in the presence of indole-3-acetamide, indole-3-propionic acid, indole-3-butyric acid, or 5-hydroxyindole-3-acetic acid. However, these indole derivatives were unable to circumvent the cAMP requirement for the induction of the lactose and the maltose operons. Catabolic repression occurred when glucose was added to cells grown in the presence of L-arabinose and 1 mM indoleacetic acid or 1 mM cAMP. This effect was reversed at higher concentrations of indoleacetic acid or cAMP. The induction and the catabolite repression phenomena were quantitated by measuring the differential rate of synthesis of L-arabinose isomerase (the araA gene product). These results indicated that indole metabolites from various living systems may regulate gene expression and may be involved in "metabolite gene regulation."

Arabinose↗
PubMed1978

Binding and functional properties of concanavalin A and its derivatives. III. Interactions with indoleacetic acid and other hydrophobic ligands.

The binding of concanavalin A to various structures via hydrophobic interactions has been studied using a variety of physicochemical assays. It was found that concanavalin A binds to nonpolar compounds such as the plant auxin beta-indoleacetic acid and its structural analogue tryptophan and that this binding is independent of the saccharide-binding activity normally associated with the lectin. The results of equilibrium dialysis experiments on the binding of beta-indoleacetic acid were consistent with the presence of a single weak binding site per subunit of protein, having an association constant of about 7 X 10(2) M-1. Competition experiments using various nonpolar compounds such as o-iodobenzoic acid suggested that this hydrophobic binding site is located in the same cavity which binds the iodine-containing ligand as shown by x-ray crystallography. Concanavalin A also binds to lipid vesicles composed of dipalmitoylphosphatidylcholine or 12-O-tetradecanoyl phorbol-13-O-acetate. This binding to lipid membranes raises the possibility that the synergistic effects of concanavalin A and tetradecanoyl phorbol acetate on lymphocyte mitogenesis may be due in part to an interaction between lectin and the phorbol ester.

Concanavalin A↗