Evaluation of Insecticides against Cowpea Sucking Insect Pests in Madhya Pradesh's Gird Region

During the Kharif season of 2022–2023 at Research Farm, Rajmata Vijyaraje Scindia Krishi Vishwa Vidyalaya, Gwalior, Madhya Pradesh, a field experiment was carried out to assess the effectiveness of seven treatments: T1 - Dimethoate 30 EC (1000 ml); T2 - Imidachloprid 17.8 SL (125 ml); T3 - Acetamiprid 20 SP (125 gm); T4 - Flubendiamide 48 SC (500 ml); T5 – Emamectin benzoate 5 SG (100 gm); T6 – Fipronil 15% SC (2000 ml); and T7 - Un-treated. The observations were made three, seven, and fifteen days after the first and second pesticide sprayings, respectively. The data indicated that Imidachloprid 17.8 SL @ 125ml ha-1 was the most effective insecticide out of the six, and that it was better at controlling the incidence of sucking insects in cowpea, such as aphids (Aphis craccivora (Koch)), thrips (M. distalis (Karny)), whiteflies (A. rachipora (Singh)), and jassids (E. kerri (Pruthi)). However, it was found that Acetamiprid 20 SP was least successful in controlling sucking insects

Correction to: A traffic light enzyme: acetate binding reversibly switches chlorite dismutase from a red- to a green-colored heme protein (JBIC Journal of Biological Inorganic Chemistry, (2020), 25, 4, (609-620), 10.1007/s00775-020-01784-1)

In the original article published, in the gy value (column) of the H2O/OH−species (row) of Table 2 was mistakenly given as “1.18” and the correct value is “2.18”.</p

Unique Biradical Intermediate in the Mechanism of the Heme Enzyme Chlorite Dismutase

The heme enzyme chlorite dismutase (Cld) catalyzes O-O bond formation as part of the conversion of the toxic chlorite (ClO2-) to chloride (Cl-) and molecular oxygen (O2). Enzymatic O-O bond formation is rare in nature, and therefore, the reaction mechanism of Cld is of great interest. Microsecond timescale pre-steady-state kinetic experiments employing Cld from Azospira oryzae (AoCld), the natural substrate chlorite, and the model substrate peracetic acid (PAA) reveal the formation of distinct intermediates. AoCld forms a complex with PAA rapidly, which is cleaved heterolytically to yield Compound I, which is sequentially converted to Compound II. In the presence of chlorite, AoCld forms an initial intermediate with spectroscopic characteristics of a 6-coordinate high-spin ferric substrate adduct, which subsequently transforms at kobs = 2-5 × 104 s-1 to an intermediate 5-coordinated high-spin ferric species. Microsecond-Timescale freeze-hyperquench experiments uncovered the presence of a transient low-spin ferric species and a triplet species attributed to two weakly coupled amino acid cation radicals. The intermediates of the chlorite reaction were not observed with the model substrate PAA. These findings demonstrate the nature of physiologically relevant catalytic intermediates and show that the commonly used model substrate may not behave as expected, which demands a revision of the currently proposed mechanism of Clds. The transient triplet-state biradical species that we designate as Compound T is, to the best of our knowledge, unique in heme enzymology. The results highlight electron paramagnetic resonance spectroscopic evidence for transient intermediate formation during the reaction of AoCld with its natural substrate chlorite. In the proposed mechanism, the heme iron remains ferric throughout the catalytic cycle, which may minimize the heme moiety's reorganization and thereby maximize the enzyme's catalytic efficiency. BT/Biocatalysi

Correction to: A traffic light enzyme: acetate binding reversibly switches chlorite dismutase from a red- to a green-colored heme protein (JBIC Journal of Biological Inorganic Chemistry, (2020), 25, 4, (609-620), 10.1007/s00775-020-01784-1)

In the original article published, in the gy value (column) of the H2O/OH−species (row) of Table 2 was mistakenly given as “1.18” and the correct value is “2.18”.BT/Biocatalysi

A traffic light enzyme: acetate binding reversibly switches chlorite dismutase from a red- to a green-colored heme protein

Abstract: Chlorite dismutase is a unique heme enzyme that catalyzes the conversion of chlorite to chloride and molecular oxygen. The enzyme is highly specific for chlorite but has been known to bind several anionic and neutral ligands to the heme iron. In a pH study, the enzyme changed color from red to green in acetate buffer pH 5.0. The cause of this color change was uncovered using UV–visible and EPR spectroscopy. Chlorite dismutase in the presence of acetate showed a change of the UV–visible spectrum: a redshift and hyperchromicity of the Soret band from 391 to 404 nm and a blueshift of the charge transfer band CT1 from 647 to 626 nm. Equilibrium binding titrations with acetate resulted in a dissociation constant of circa 20 mM at pH 5.0 and 5.8. EPR spectroscopy showed that the acetate bound form of the enzyme remained high spin S = 5/2, however with an apparent change of the rhombicity and line broadening of the spectrum. Mutagenesis of the proximal arginine Arg183 to alanine resulted in the loss of the ability to bind acetate. Acetate was discovered as a novel ligand to chlorite dismutase, with evidence of direct binding to the heme iron. The green color is caused by a blueshift of the CT1 band that is characteristic of the high spin ferric state of the enzyme. Any weak field ligand that binds directly to the heme center may show the red to green color change, as was indeed the case for fluoride.BT/Biocatalysi