The metabolic fate of 14C‐parathion by some fresh water phytoplankton and its possible effects on the algal metabolism

Abstract

The growth and total carbohydrate contents of Nostoc muscorum and Tolypothrix tenuis were greatly and significantly reduced by the application of parathion. “Chlorophyll a”, carotene biosynthesis and the rate of glucose absorption were enhanced after supplementation of parathion to the culture media of both cyanobacteria. Nitrogen released to the media, total nitrogen content and total nitrogen fixed were increased in both organisms‐ Increase in protein content was accompanied by remarkable drop in amino, peptide and ammonia fractions‐ Phosphorus uptake, RNA, DNA and total phosphorus content were accelerated to reach maximum accumulation at the highest insecticide level. In metabolism study using ¹⁴C‐labelled compound, parathion was readily degraded by Nostoc and Tolypothrix. Following ten days incubation, the aqueous fractions contained 21.1% and 18.1% of the initial activity in Nostoc and Tolypothrix respectively. TLC analysis of the hydrolytic products revealed the presence of three metabolites: p‐aminophenol, p‐nitrophenol and aminoparathion.     

Melatonin exerts a neuroprotective effect against γ-radiation-induced brain injury in the rat through the modulation of neurotransmitters,inflammatory cytokines,oxidative stress,and apoptosis

Environmental Science and Pollution Research - The current study aimed to investigate the ameliorative effect of melatonin (MLT) against brain injury in rats undergoing whole-body exposure to...     

Levels of dechlorane plus and polybrominated diphenylethers in human milk in two Canadian cities

Flame retardant dechlorane plus (DP) and several polybrominated diphenylether (PBDE) congeners have been measured in 87 human milk samples collected in two Canadian cities: Kingston and Sherbrooke. The levels of PBDEs in human milk (mean (median), ng g^− 1 lipid weight = 10 (5.9), 4.1 (2.8), 3.0 (1.6), 5.12 (1.6), and 15 (ND) for BDE-47, BDE-99, BDE-100, BDE-153, and BDE-209, respectively) were comparable to those reported in Europe, U.S.A. and China. The levels of DP, with a mean value of 0.98 ng g^− 1 and a median value of 0.60 ng g^− 1 (lipid weight), were two to ten times lower than those of concurrently measured major PBDEs including BDE-209. While there is little difference in the levels of measured contaminants in milk samples collected from the two cities, the contaminants levels in human milk show, indicated by Principal Components Analysis, that DP, deca-BDE, and penta-BDE come from three distinct sources. The mean and median isomer ratio values of DP in milk were 0.67 and 0.69, respectively, very similar to that of DP commercial products.     

Assessment of the global fallout of plutonium isotopes and americium-241 in the soil of the central region of Saudi Arabia

A radiochemical technique for determination of plutonium isotopes and 241Am in soil samples is tested against IAEA-standard reference materials to determine its accuracy and precision for reliable results. The technique is then used in the investigation of topsoil samples, collected from the natural environment of the central region of Saudi Arabia, to assess the effect of fallout accumulation of these radionuclides in the region. Plutonium and americium were sequentially separated from all other components of the sample by anion-exchange chromatography and co-precipitated with Nd3+ as fluorides. The precipitates were mounted on membrane filters and measured using a high-resolution alpha-spectrometer. The results of the analysis of the reference materials showed satisfactory sensitivity and precision of the technique. The results of the analyzed soil samples show activity levels ranging from < LLD to 0.089 and from 相似文献   

Exploring antibiotic resistance genes,mobile gene elements,and virulence gene factors in an urban freshwater samples using metagenomic analysis

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Air pollution and child health: the impact of brick kiln pollution on children's cognitive abilities and physical health in Pakistan

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Sources and environmental behavior of dechlorane plus--a review

Intensive research has been carried out in the past few years on the occurrence and behavior of dechlorane plus (DP) in the environment, biota and humans. This review summarizes the information and research results generated since DP was first identified in the environment in 2006. We describe the reported measurement methods for DP and provide an integrated picture of its occurrence and behavior as an environmental contaminant. DP in ambient air and sediments is characterized by strong source related concentration elevations and temporal trends reflecting commercial use. Long-range atmospheric transportation of DP has been observed in remote regions, indicating a global presence of DP. Levels of DP in biota and in humans further reinforce its source related distribution. The change in DP isomer ratio in various environmental matrices from commercial products indicates that the behavior of the two isomers is not the same in the environment or in biota. With only limited data available so far, the biomagnification of DP in aquatic biota has not been conclusively demonstrated. This review also looks at reported dechlorination products of DP that might be of interest in future research.     

The impact of mucormycosis (black fungus) on SARS-CoV-2-infected patients: at a glance

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