Investigation of acute toxicity of fenitrothion on guppies Poecilia reticulata

Development of a bioluminescence resonance energy transfer Quenchbody sensor for the detection of organophosphorus pesticides in water bodies

Rapid and precise quantification of organophosphorus pesticides (OPPs) in environmental water bodies is crucial for evaluating ecological risks and safeguarding human health. Traditional instrumental methods are complex, time-consuming, and expensive, while enzyme-based biosensors suffer from instability and require a constant supply of substrates. Hence, there is an urgent need for a fast, simple, and sensitive biosensor for OPPs. In this study, we developed a novel non-enzymatic biosensor for the detection of methyl parathion (MP) by employing the bioluminescence resonance energy transfer (BRET) Q-body strategy. Optimizing the spacer arm and screening fluorescent dyes identified the R6G BRET MP Q-body sensor with the best performance. Key parameters affecting the sensor's detection performance were optimized by using single-factor experiments. Under optimal conditions, the detection exhibited a detection limit of 5.09 ng·mL-1 and a linear range of 16.21-848.81 ng·mL-1. The sensor's accuracy was validated using standard recovery experiments, yielding a recovery rate of 84.47 %-102.08 % with a standard deviation of 1.93 %-9.25 %. The detection results of actual water samples demonstrate that this fast, simple, and highly sensitive BRET Q-body sensor holds great promise for practical water quality monitoring.

Diuron, Irgarol 1051 and Fenitrothion contamination for a river passing through an agricultural and urban area in Higashi Hiroshima City, Japan

A study was conducted on the pesticides Diuron, Irgarol 1051 and Fenitrothion in Kurose River water, Higashi Hiroshima, Japan for a period of one year to assess the contribution of agriculture and urban activities on pesticide pollution of the river. Samples were analysed by a reverse phase HPLC system. The maximum pesticide concentrations were; 4620 ng/L, 50 ng/L and 370 ng/L for Diuron, Irgarol 1051 and Fenitrothion, respectively. While Diuron and Fenitrothion were detected at all sites, Irgarol 1051 was only present at Izumi, a high density urban and industrial area which also registered the highest concentrations of the pesticides. The pattern showed by Diuron and Fenitrothion was linked to farming activities. Also, Diuron and Fenitrothion concentration correlated with pesticide utilization data for Hiroshima Prefecture. Irgarol 1051 showed a different pattern to that of Diuron and Fenitrothion and its source was attributed to paint. It was noted that 78% and 42% of water samples at Izumi sampling site exceeded the European Union (EU) guidelines for Diuron and Fenitrothion, respectively.

Larvicidal activity of the extract of seaweed, Caulerpa scalpelliformis, against Culex pipiens

The larvicidal efficacy of the acetone extract of the thalli of Caulerpa scalpelliformis var. denticulata was determined against late 2nd to early 3rd instars of Culex pipiens at concentrations ranging from 100 to 2,000 parts per million (ppm). At 1,200 ppm, the extract caused >70% larval mortality at 24-, 48-, and 72-h exposure. The LC50 (lethal concentration) and LC90 values of C. scalpelliformis were 338.91 and 1,891.31 ppm, respectively. Our data showed that this species of seaweed contains components with larvicidal properties against mosquitoes.