scholarly journals Biochemical Characterization of Recombinant UDPG-Dependent IAA Glucosyltransferase from Maize (Zea mays)

2021 ◽  
Vol 22 (7) ◽  
pp. 3355
Author(s):  
Anna Ciarkowska ◽  
Maciej Ostrowski ◽  
Anna Kozakiewicz
Keyword(s):  
Biochemical Characterization ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Relative Activity ◽  
Dichlorophenoxyacetic Acid ◽  
Low Concentrations ◽  
Unique Effect ◽  
Potential Binding ◽  
2,4 Dichlorophenoxyacetic Acid

Here, we report a biochemical characterization of recombinant maize indole-3-acetyl-β-d-glucose (IAGlc) synthase which glucosylates indole-3-acetic acid (IAA) and thus abolishes its auxinic activity affecting plant hormonal homeostasis. Substrate specificity analysis revealed that IAA is a preferred substrate of IAGlc synthase; however, the enzyme can also glucosylate indole-3-butyric acid and indole-3-propionic acid with the relative activity of 66% and 49.7%, respectively. KM values determined for IAA and UDP glucose are 0.8 and 0.7 mM, respectively. 2,4-Dichlorophenoxyacetic acid is a competitive inhibitor of the synthase and causes a 1.5-fold decrease in the enzyme affinity towards IAA, with the Ki value determined as 117 μM, while IAA–Asp acts as an activator of the synthase. Two sugar-phosphate compounds, ATP and glucose-1-phosphate, have a unique effect on the enzyme by acting as activators at low concentrations and showing inhibitory effect at higher concentrations (above 0.6 and 4 mM for ATP and glucose-1-phosphate, respectively). Results of molecular docking revealed that both compounds can bind to the PSPG (plant secondary product glycosyltransferase) motif of IAGlc synthase; however, there are also different potential binding sites present in the enzyme. We postulate that IAGlc synthase may contain more than one binding site for ATP and glucose-1-phosphate as reflected in its activity modulation.

Herbicide-Induced Ethylene Production: Role of the Gas in Sublethal Doses of 2,4-D

Weed Science ◽  
1968 ◽  
Vol 16 (4) ◽  
pp. 498-500 ◽  
Author(s):  
F. B. Abeles
Keyword(s):  
Carbon Dioxide ◽  
Zea Mays ◽  
Glycine Max ◽  
Ethylene Production ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Dichlorophenoxyacetic Acid ◽  
Sublethal Doses ◽  
2,4 Dichlorophenoxyacetic Acid

Ethylene production was stimulated by 2,4-dichlorophenoxyacetic acid (2,4-D) from light-grown corn (Zea mays L., var. XL-15) and soybeans (Glycine max Merr., var. Hawkeye). Ethylene had an inhibitory effect on the growth of corn and soybeans, but a reversal of the ethylene effect could not be clearly demonstrated using the competitive inhibitor, carbon dioxide. Ethylene did not mimic the ability of 2,4-D to cause growth curvatures. It was concluded that ethylene played a role in the activity of sublethal amounts of 2,4-D.

Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig
Keyword(s):  
Field Experiments ◽  
Reproductive Mode ◽  
Dichlorophenoxyacetic Acid ◽  
Initial Field ◽  
Breeding Lines ◽  
Reproductive Modes ◽  
Desert Southwest ◽  
2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

Initiation and morphological development of somatic embryoids from barley cell cultures

1984 ◽  
Vol 62 (6) ◽  
pp. 1245-1249 ◽  
Author(s):  
L. S. Kott ◽  
K. J. Kasha
Keyword(s):  
Somatic Embryogenesis ◽  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Cell Cultures ◽  
Dichlorophenoxyacetic Acid ◽  
Morphological Development ◽  
Low Concentrations ◽  
The Media ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Barley Cell

Somatic embryogenesis was induced in callus previously initiated from immature embryos of barley. These cultures ranged in age from 6 weeks to 30 months. Embryoids were readily initiated from homogenized suspension-grown aggregates when plated on modified B5 media with 2,4-dichlorophenoxyacetic acid. Low concentrations (0.1 and 0.05 mg∙L−1) of abscisic acid promoted further maturation of embryoids, while gibberellic acid (1 mg∙L−1) and kinetin (0.1 mg∙L−1) were used in the media to encourage embryoid germination. The development of somatic embryoids from initiation through maturation and germination is described.

scholarly journals Characterization of Hapten-Protein Conjugates: Antibody Generation and Immunoassay Development for Chlorophenoxyacetic Acid Pesticides

2009 ◽  
Vol 92 (6) ◽  
pp. 1773-1779 ◽  
Author(s):  
Robin C Boro ◽  
K Vikas Singh ◽  
C Raman Suri
Keyword(s):  
Inhibitory Concentration ◽  
Dichlorophenoxyacetic Acid ◽  
Protein Conjugation ◽  
Protein Conjugates ◽  
Highly Sensitive ◽  
Ic50 Values ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1500 ng/mL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

scholarly journals Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae)

2010 ◽  
Vol 70 (2) ◽  
pp. 361-366 ◽  
Author(s):  
MBB Cassanego ◽  
A Droste ◽  
PG Windisch
Keyword(s):  
Primary Root ◽  
The State ◽  
Dichlorophenoxyacetic Acid ◽  
Agricultural Activities ◽  
Rio Grande Do Sul ◽  
Initial Development ◽  
Low Concentrations ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Sporophytic Development

Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyer's medium. Cultures were maintained in a growth chamber at 24 ± 1 °C, under artificial light with nominal irradiance of 110 µmol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48%, respectively), compared with the control (68%). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.

Characterization of CDPdiacylglycerol hydrolase in mitochondrial and microsomal fractions from rat lung

1988 ◽  
Vol 66 (5) ◽  
pp. 425-435 ◽  
Author(s):  
Amy Mok ◽  
Tanya Wong ◽  
Octavio Filgueiras ◽  
Paul G. Casola ◽  
Don W. Nicholson ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Mitochondrial Activity ◽  
Rat Lung ◽  
Ph Optimum ◽  
Low Concentrations ◽  
Mercuric Ions

CDPdiacylglycerol pyrophosphatase (E. C. 3.6.1.26) activity has been examined in rat lung mitochondrial and microsomal fractions. While the mitochondrial hydrolase exhibited a broad pH optimum from pH 6–8, the microsomal activity decreased rapidly above pH 6.5. Apparent Km values of 36.2 and 23.6 μM and Vmax values of 311 and 197 pmol∙min−1∙mg protein−1 were observed for the mitochondrial and microsomal preparations, respectively. Addition of parachloromercuriphenylsulphonic acid led to a marked inhibition of the microsomal fraction but slightly stimulated the mitochondrial activity at low concentrations. Mercuric ions were inhibitory with both fractions. Although biosynthetic reactions utilizing CDPdiacylglycerol require divalent cations, addition of Mg2+, Mn2+, Ca2+, Zn2+, Co2+, and Cu2+ all inhibited the catabolic CDPdiacylglycerol hydrolase activity in both fractions. EDTA and EGTA also produced an inhibitory effect, especially with the mitochondrial fraction. Although addition of either adenine or cytidine nucleotides led to a decrease in activity with both fractions, the marked susceptibility to AMP previously reported for this enzyme in Escherichia coli membranes, guinea pig brain lysosomes, and pig liver mitochondria was not observed. These results indicate that rat lung mitochondria and microsomes contain specific CDPdiacylglycerol hydrolase activities, which could influence the rate of formation of phosphatidylinositol and phosphatidylglycerol for pulmonary surfactant.

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