Phytotoxicity of different antibiotics to rice and stress alleviation upon application of organic amendments
CHEMOSPHERE
Authors: Mukhtar, Ayesha; Manzoor, Maria; Gul, Iram; Zafar, Rabeea; Jamil, Hira Imam; Niazi, Adnan Khan; Ali, Muhammad Arif; Park, Tae Jung; Arshad, Muhammad
Abstract
Extensive use of antibiotic results in significant antibiotics pollution in the environment. Main objective of this study was to gain insight into potential impacts of antibiotics on plant physiological growth and nutritional composition, and stress alleviation through application of different organic amendments. Effects of five antibiotics (ciprofloxacin, levofloxacin, ofloxacin, amoxicillin and ampicillin) were observed in the presence of three organic amendments (rice husk, farmyard manure and poultry litter) with rice (Oryza sativa L.) as a model plant. Organic amendments were mixed with soil (@ 5 g kg(-1)) and after three weeks, antibiotics were applied (@10 mg kg(-1)) and plants were allowed to grow for four months. After which plants were harvested and physical growth parameters (root/shoot length, biomass) and nutritional composition (grain protein content, carbohydrates, phosphorous and iron) were monitored. It was observed that germination rate, seedling root/shoot length, seedling biomass and vigor index were negatively impacted. The application of organic amendments alleviated antibiotic stress on seedling dry biomass, length and vigor index by 1.8-, 3.1- and 2.5-folds, respectively as compared to the antibiotic controls. Concentrations of phosphorous, iron, carbohydrates and proteins were decreased by 5.3-, 1.3-, 1.4- and 1.6-folds upon application of antibiotics. Rice husk was the most effective treatment in case of physical growth parameters and alleviating antibiotics' induced genotoxicity. Whereas, poultry litter had the highest positive effect on nutritional composition of plants. In general, the application of organic amendments alleviated the phytotoxicity as well as genotoxicity in plants under antibiotics stress. (C) 2020 Elsevier Ltd. All rights reserved.
D-Aspartate N-methyltransferase catalyzes biosynthesis of N-methyl-D-aspartate (NMDA), a well-known selective agonist of the NMDA receptor, in mice
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS
Authors: Shibata, Kimihiko; Imanishi, Daiki; Abe, Katsumasa; Suzuki, Masataka; Takahashi, Shouji; Kera, Yoshio
Abstract
N-Methyl-D-aspartate (NMDA), which is a selective agonist for the NMDA receptor, has recently been shown to be present in various biological tissues. In mammals, the activity of D-aspartate N-methyltransferase (DDNMT), which produces NMDA from D-aspartate, has been detected only in homogenates prepared from rat tissues. Moreover, the enzymatic properties of DDNMT have been poorly studied and its molecular entity has not yet been identified. In this report, we show for the first time that the activity of DDNMT is present in mouse tissues and succeed in obtaining a partially purified enzyme preparation from a mouse tissue homogenate with a purification fold of 1900 or more, and have characterized the enzymatic activity of this preparation. The results indicate that DDNMT, which is highly specific for D-aspartate and is S-adenosyl-L-methionine-dependent, is a novel enzyme that clearly differs from the known methylamine-glutamate N-methyltransferase (EC 2.1.1.21) and glycine N-methyltransferase (EC 2.1.1.20).