Endogenous biosynthetic precursors of (+)-abscisic acid. VII. The 1′,4′-trans-diol is formed from ABA, it is not a precursor

1998 ◽  
Vol 25 (6) ◽  
pp. 729 ◽  
Author(s):  
B. V. Milborrow ◽  
H.-S. Lee
Keyword(s):  
Abscisic Acid ◽  
Mung Bean ◽  
Cold Trap ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Plant Tissues ◽  
Bean Seedling ◽  
Avocado Fruit ◽  
In Trans ◽  
Reducing Potential

[14C]ABA fed to avocado fruit is known to be converted into the 1′,4′-trans-diol and [14C]1′,4′-trans-diol has been shown to be converted into ABA by several plant tissues. As a ‘cold trap’of trans-diol becomes labelled with 14C when [14C]mevalonate is converted into ABA, the trans-diol has been suggested to be the immediate precursor of ABA. This proposal has now been tested by feeding [5-14C,5-3H2]mevalonolactone to unripe avocado fruit and measuring the 3H :14C ratio in the ABA and in the 1′,4′-trans-diol isolated from the fruit after 16 h. Little labelled diol was present unless a ‘cold trap’ of unlabelled 1,4-trans-diol was added with the mevalonate. One 3H atom, derived from those at C-5 of mevalonate, would be expected at C-4′ of the diol, adjacent to the hydroxyl group, and another at C-5 of the side chain of the diol if the diol were a precursor of ABA (3H:14C ratio of 2:3). However, if the 4′-hydroxyl group had been oxidised to a ketone to form ABA, then the 3H atom at C-4′ of the diol would have been lost and the 3H:14C ratio would be expected to be 1:3. The normalised 3H : 14C ratios of ABA and 1′,4′-trans-diol biosynthesised from [14C,5-3H2]mevalonate were 0.915:3 and 0.844:3 respectively and after oxidation of the diol to ABA with MnO2 the ratio was 0.869:3 i.e. there was no 3H at C-4′ of the diol. These ratios are as expected for the trans-diol if it had been formed by reduction of ABA. This, and the absence of labelled diol in the fruit unless a ‘cold trap’was added, establishes that the 1′,4′-trans-diol is formed from ABA and it is not a precursor. The formation of the diols from newly synthesised labelled ABA in cell-free systems can be attributed to the addition to the homogenate of compounds with strong reducing potential. NADPH2+ (8.4 nmol) added to a mung bean seedling homogenate caused the reduction of (±)-[14C]ABA (0.37 nmol, 22.5 µCi/mol) to trans-diol (1189 dpm) whereas with NADP+ only 338 dpm were present in trans-diol. Glutathione (46 nmol) caused the formation of 1214 dpm while oxidised glutathione produced 638 dpm. Less 1′,4′-cis-diol was formed.

17α-HYDROXYLASE DEFICIENCY. A COMBINATION OF HYDROXYLATION DEFECT AND REVERSIBLE BLOCKADE IN ALDOSTERONE BIOSYNTHESIS

1979 ◽  
Vol 90 (3) ◽  
pp. 490-504 ◽  
Author(s):  
D. R. Rovner ◽  
J. W. Conn ◽  
E. L. Cohen ◽  
F. G. Berlinger ◽  
D. C. Kern ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Extracellular Fluid ◽  
Plasma Renin ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Hydroxylase Deficiency ◽  
Resultant Increase

ABSTRACT We have studied the hormonal secretion and excretion patterns in a patient with the XX type of 17α-hydroxylase deficiency. In the untreated state, the patient's urine contained only those steroids which do not require 17-hydroxylation in their biosynthesis. Aldosterone was not produced in the patient and the metabolic product of its immediate precursor, 18-hydroxy-11-dehydro-tetrahydrocorticosterone, was excreted in markedly elevated amounts. This apparent complete block in 18 oxidation was reversible upon long-term ACTH suppression within 27 days. Direct in vitro incubation of the patient's adrenal gland removed at operation demonstrated, 1) the complete lack of 17α-hydroxylase activity, 2) the functional block in the ability to oxidize the hydroxyl group at the 18 methyl side chain. The addition of physiological concentrations of angiotensin to the incubation medium further showed, 3) angiotensin mildly stimulated the entire aldosterone biosynthetic pathway, 4) angiotensin directly stimulated the conversion of 18-hydroxycorticosterone to aldosterone. We propose that in this patient, 17-hydroxylase deficiency produced a decreased plasma concentration of cortisol, followed by stimulation of deoxycorticosterone production by ACTH. The resultant increase in extracellular fluid volume suppressed plasma renin activity. This resulted in a low plasma concentration of angiotensin II which directly suppressed oxidation of 18-hydroxycorticosterone to aldosterone. This defect has been called corticosterone methyl oxidase defect type 2.

scholarly journals Abscisic acid analogs with a geometrically rigid conjugated acid side-chain.

1986 ◽  
Vol 50 (4) ◽  
pp. 1097-1100 ◽  
Author(s):  
S. C. CHEN ◽  
J. M. MACTAGGART
Keyword(s):  
Abscisic Acid ◽  
Side Chain

scholarly journals Studies on the Antibacterial Influence of Two Ionic Liquids and their Corrosion Inhibition Performance

2020 ◽  
Vol 10 (4) ◽  
pp. 1444 ◽  
Author(s):  
Mohamed F. Shehata ◽  
Ashraf M. El-Shamy ◽  
Khaled M. Zohdy ◽  
El-Sayed M. Sherif ◽  
Sherif Zein El Abedin
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Synergistic Effect ◽  
Corrosion Inhibition ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Imidazolium Cation ◽  
Corrosion Effect ◽  
Inhibition Performance

In this paper the anti-bacterial and the anti-corrosion effect of two different ionic liquids, namely 1-(2-hydroxyethyl)-3-methylimidazolinium chloride ([OH-EMIm]Cl) and 1-ethyl-3-methyleimidazolinium chloride ([EMIm]Cl) was demonstrated. The results revealed that the corrosion inhibition influence of the ionic liquid [OH-EMIm]Cl is higher than that of the ionic liquid [EMIm]Cl. Furthermore, the ionic liquid [OH-EMIm]Cl showed better biocidal influence compared with the ionic liquid [EMIm]Cl. This indicates the synergistic effect due to the incorporation of the hydroxyl group into the side chain of the imidazolium cation leading to enhanced antibacterial and anticorrosion effect.

scholarly journals Laser Irradiation of Mung Bean (Vigna radiata L.) at Two Wavelengths for Enhanced Seedling Development

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Rayno Vic B. Janayon ◽  
Raphael A. Guerrero
Keyword(s):  
Laser Irradiation ◽  
Vigna Radiata ◽  
Mung Bean ◽  
Continuous Wave ◽  
Hypocotyl Length ◽  
Maximum Increase ◽  
Bean Seedling ◽  
Laser Sources ◽  
Level Of Significance ◽  
Seedling Characteristics

Two laser sources operating at wavelengths of 632.8 nm (He-Ne) and 488 nm (Ar+) are used in examining the effects of coherent, low-power, continuous wave exposure on the development of Vigna radiata L. Presowing laser irradiation of seeds leads to an improvement of mung bean seedling characteristics, with increased values of hypocotyl length (an increase of up to 22.5%), root length (an increase of up to 28.8%), and seedling mass (a maximum increase of 29.2%). Measured parameters between seedlings from laser-irradiated seeds and from control samples are statistically different at a level of significance equal to 0.05. For both laser wavelengths, an optimal exposure time of 2 minutes is determined for enhanced growth of mung bean seedlings.

scholarly journals N-(5′-Phosphopyridoxyl)glutamic acid and N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid and their action on the apoenzyme of aspartate aminotransferase

1971 ◽  
Vol 124 (1) ◽  
pp. 99-106 ◽  
Author(s):  
R M. Khomutov ◽  
H B. F. Dixon ◽  
L V. Vdovina ◽  
M P. Kirpichnikov ◽  
Y V. Morozov ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Aspartate Aminotransferase ◽  
Fluorescence Spectra ◽  
Pyridoxal Phosphate ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Compound I ◽  
Compound Ii

1. N-(5′-Phosphopyridoxyl)-l-glutamic acid (P-Pxy-Glu, compound I) is readily converted at pH3 into a substance (P-Pxy-Glp, compound II) characterized as N-(5′-phosphopyridoxyl)-2-oxopyrrolidine-5-carboxylic acid. 2. The u.v., i.r. and fluorescence spectra of P-Pxy-Glu and P-Pxy-Glp have been determined; from the u.v. spectra their pK values have been found and compared. 3. The apoenzyme of aspartate aminotransferase is rapidly and irreversibly inactivated by P-Pxy-Glu, but is inactivated more slowly by P-Pxy-Glp. The complex with P-Pxy-Glp is stable enough to be isolated, but it is slowly reactivated in the presence of excess of pyridoxal phosphate. 4. The u.v. spectrum of the complex of apoenzyme and P-Pxy-Glp suggests that it contains a hydrogen bond between the phenolic hydroxyl group and the pyrrolidone nitrogen; this specifies the conformation of most of the molecule of P-Pxy-Glp. This conformation is similar to that previously postulated for the enzyme–glutamate complex except for the side chain of glutamate. Hence both the affinity of P-Pxy-Glp for the apoenzyme and the fact that it is more easily removed than P-Pxy-Glu are explicable.

Newly Synthesized Branch-type Aromatic Oxadiazole Polymer and Binary Fluorescence Patterning on its Film

2007 ◽  
Vol 19 (5-6) ◽  
pp. 531-540 ◽  
Author(s):  
Moon Soo Choi ◽  
Hyung Jun Kim ◽  
Taek Seung Lee ◽  
Won Seok Lyoo
Keyword(s):  
Coupling Reaction ◽  
Side Reaction ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Aromatic Side Chain ◽  
Suzuki Coupling Reaction ◽  
Color Changes ◽  
Fluorescence Color ◽  
Before And After ◽  
Photochemical Cleavage

Aromatic side-chain oxadiazole polymer linked with 9,9'-dioctylfluorene was successfully synthesized via Suzuki coupling reaction. Hydroxyphenyl group was attached in the 2-position of the oxadiazole unit in the polymer side chain to control the optical properties of the polymer. We confirmed the presence of the t-butoxycarbonyl group on the hydroxyl group using thermogravimetric analysis, which was incorporated to avoid side reaction during polymerization. We also performed the simple and easy fabrication method for the dual fluorescence image using photochemical cleavage of the t-butoxycarbonyl group from the polymer to induce fluorescence color changes before and after UV irradiation.

Interaction between the pili of Pseudomonas aeruginosa PAK and its carbohydrate receptor β-D-GalNAc(1->4) β-D-Gal analogs

1998 ◽  
Vol 44 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Frank Schweizer ◽  
Hailong Jiao ◽  
Ole Hindsgaul ◽  
Wah Y Wong ◽  
Randall T Irvin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Binding Assay ◽  
Solid Phase ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Surface Receptors ◽  
Order Of Magnitude ◽  
Epithelial Cell Surface ◽  
Solid Phase Binding

Pseudomonas aeruginosa employs pili to mediate adherence to epithelial cell surface receptors. Previously, it has been shown that the pilus adhesin of P. aeruginosa PAK binds to the ganglioside asialo-GM1. In particular, it was found that the carbohydrate sequence β-D-GalNAc(1->4) β-D-Gal is the minimal carbohydrate receptor sequence of asialo-GM1. To study the binding specificity of P. aeruginosa, O-modified and N-modified sugar analogs, where each hydroxyl group was substituted either by O-methyl or O-propyl and the acetamido group was changed to a propionamido group, were synthesized. The sugar analogs were evaluated as inhibitors in a competitive solid phase binding assay. The results demonstrate that the pili of P. aeruginosa PAK accepts a variety of sugar analogs possessing the sequence β-D-GalNAc(1->4) β-D-Gal. Most sugar analogs bind with a similar order of magnitude (50% inhibitory concentration (IC50) = 60-130 μM) except for the 2-O-propyl derivative 7 (IC50 = 8 ± 4 μM) compared with an IC50 of 79 ± 18 μM for the native compound. The significant increase in binding affinity of 2-O-propyl derivative 7 suggests that improved inhibitors of adhesion may be prepared by introducing a hydrophobic side chain at the 2-position of galactose.Key words: Pseudomonas aeruginosa, pili, adhesion, carbohydrate.

ESTIMATION OF CORTICOSTEROIDS BY THE REDUCTION OF FERRICYANIDE

1959 ◽  
Vol 37 (1) ◽  
pp. 391-398 ◽  
Author(s):  
N. R. Stephenson
Keyword(s):  
Prussian Blue ◽  
Blood Sugar ◽  
Alkaline Medium ◽  
Alkaline Solution ◽  
Reducing Power ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Inhibiting Effect ◽  
Reducing Activity ◽  
Hydrolysis Of

A procedure based on a modification of Folin's micromethod for blood sugar (1, 2) was used to investigate the reducing activity of various corticosteroids. The ferrocyanide produced as a result of the reduction of ferricyanide in alkaline solution was measured photometrically as Prussian blue. With a filter transmitting light at 620 mμ, the relation between the absorbance of the chromogen and the amount of the reducing steroid obeyed Beer's law over the range from 0.005 to 0.050 mg. The oxygen function at C-3 accounted for most of the reducing power of the non-alpha ketolic steroids studied. An oxygen function at C-11 did not affect significantly the reduction of ferricyanide by 17-desoxycorticosteroids. Although the presence of a hydroxyl at C-17 depressed the reducing activity of the alpha-ketol side chain, a fluorine at C-9 and an hydroxyl at C-11 appeared to overcome this inhibiting effect. Evidence was obtained to suggest that a C-16 hydroxyl group was able to increase the reducing action of the alpha-ketolic side chain. Esterification of the C-21 hydroxyl influenced the reduction of ferricyanide only when interference with hydrolysis of the ester in the alkaline medium was experienced.

scholarly journals Recent Advances on Macrocyclic Trichothecenes, Their Bioactivities and Biosynthetic Pathway

Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 417
Author(s):  
Muzi Zhu ◽  
Youfei Cen ◽  
Wei Ye ◽  
Saini Li ◽  
Weimin Zhang
Keyword(s):  
Phylogenetic Trees ◽  
Biosynthetic Pathway ◽  
Antitumor Agents ◽  
Food Contamination ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Important Group ◽  
Search Results ◽  
Macrocyclic Trichothecenes ◽  
Biologic Activity

Macrocyclic trichothecenes are an important group of trichothecenes bearing a large ring. Despite the fact that many of trichothecenes are of concern in agriculture, food contamination, health care and building protection, the macrocyclic ones are becoming the research hotspot because of their diversity in structure and biologic activity. Several researchers have declared that macrocyclic trichothecenes have great potential to be developed as antitumor agents, due to the plenty of their compounds and bioactivities. In this review we summarize the newly discovered macrocyclic trichothecenes and their bioactivities over the last decade, as well as identifications of genes tri17 and tri18 involved in the trichothecene biosynthesis and putative biosynthetic pathway. According to the search results in database and phylogenetic trees generated in the review, the species of the genera Podostroma and Monosporascus would probably be great sources for producing macrocyclic trichothecenes. Moreover, we propose that the macrocyclic trichothecene roridin E could be formed via acylation or esterification of the long side chain linked with C-4 to the hydroxyl group at C-15, and vice versa. More assays and evidences are needed to support this hypothesis, which would promote the verification of the proposed pathway.

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