Effects of commonly used carbamates (carbaryl and thiram) on the regulatory, secretory and motor functions of bovine cervixes in vitro

Previously studied classes of pesticides, including organochlorines, organophosphates and pyrethroids disturb the mechanism that causes bovine myometrial contractions. Hence, the aim of this study was to investigate the effects of carbaryl and thiram, which are representative carbamate pesticides commonly used in global agriculture, on the motor and secretory functions of bovine cervixes. Additionally, the impacts of these pesticides on intra- and intercellular signaling in vitro were estimated. In this study, cervical cells or strips were obtained from cows at days 18-20 of the estrous cycle and were treated with carbaryl or thiram. Neither carbamate (10 or 100 ng/ml) exerted cytotoxic effects. Carbaryl increased the level of mRNA (at a dose of 0.1 ng/ml) and protein (at both doses, 1 and 10 ng/ml) expression for the oxytocin receptor (OXTR), while thiram (at 0.1 and 10 ng/ml or 0.1-10 ng/ml, respectively) caused the opposite effects. Moreover, the level of the second messenger inositol-trisphosphate (IP3) was decreased by carbaryl (10 ng/ml) but increased by thiram (10 ng/ml). Only thiram decreased prostaglandin-endoperoxide synthase 2 (PTGS2; 0.1 ng/ml) and aldo-keto reductase family 1, member B1 (AKR1B1; 0.1 ng/ml), and prostaglandin E synthase 2 (PTGES2; 0.1-10 ng/ml) mRNA expression, while thiram (0.1-10 ng/ml) and carbaryl (0.1 and 10 ng/ml) both decreased the release of PGF2α. Carbaryl (10 ng/ml) and thiram (10 ng/ml) also decreased the level of a gap junction protein (GAP). Moreover, carbaryl (10 ng/ml) decreased the level of myosin light chain kinase (MLCK). However, the strength of cervical contractions was increased by thiram (1 and 10 ng/ml) but decreased by carbaryl (1 and 10 ng/ml). Carbaryl increased the receptivity of cervical cells to oxytocin (OXT), but inhibited further transduction (IP3) of this signal. Hence, direct inhibition of cervical strip contraction may occur. In contrast, thiram mostly decreased the receptivity of cervical cells to OXT, while it stimulated the contraction of cervical strips. Moreover, compared to carbaryl, thiram more greatly affected the synthesis and release of prostaglandins. These results suggest that carbaryl and thiram disturb OXT signaling, PG secretion and cervical contraction in vitro.

Determination of pioglitazone hydrochloride by flow injection chemiluminescence tris(2,2'-bipyridyl)ruthenium(II)-silver(III) complex system

A novel flow injection-chemiluminescence (FI-CL) approach is proposed for the assay of pioglitazone hydrochloride (PG-HCl) based on its enhancing influence on the tris(2,2'-bipyridyl)ruthenium(II)-silver(III) complex (Ru(bipy)₃ ²⁺ -DPA) CL system in sulfuric acid medium. The possible CL reaction mechanism is discussed with CL and ultraviolet (UV) spectra. The optimum experimental conditions were found as: Ru(bipy)₃ ²⁺ , 5.0 × 10^-5  M; sulfuric acid, 1.0 × 10^-3  M; diperiodatoargentate(III) (DPA), 1.0 × 10^-4  M; potassium hydroxide, 1.0 × 10^-3  M; flow rate 4.0 ml min^-1 for each flow stream and sample loop volume, 180 μl. The CL intensity of PG-HCl was linear in the range of 1.0 × 10^-3 to 5.0 mg L^-1 (R²  = 0.9998, n = 10) with limit of detection [LOD, signal-to-noise ratio (S/N) = 3] of 2.2 × 10^-4  mg L^-1 , limit of quantification (LOQ, S/N = 10) of 6.7 × 10^-4  mg L^-1 , relative standard deviation (RSD) of 1.0 to 3.3% and sampling rate of 106 h^-1 . The methodology was satisfactorily used to quantify PG-HCl in pharmaceutical tablets with recoveries ranging from 93.17 to 102.77 and RSD from 1.9 to 2.8%.

Determination of thiram residues in fresh water using flow injection diperiodatonickelate(IV)-quinine chemiluminescence detection

This study developed a simple flow injection (FI) method based on diperiodatonickelate(IV)-sulfuric acid reaction using chemiluminescence (CL) detection for the determination of thiram (THI) fungicide in fresh water using quinine as the sensitizer. The possible mechanism of the CL reaction was described using UV-Vis. absorption and CL spectra. Experimental variables were optimized by applying a univariate approach, and a linear calibration curve was obtained in the range of 1.0 × 10^-3 -2.0 mg L^-1 (R²  = 0.9994, n = 9) with a limit of detection of 5.0 × 10^-4  mg L^-1 (S/N = 3) and an injection throughput of 200 h^-1 . This approach was successfully applied to determine THI in fresh water by using solid-phase extraction and achieved a good recovery rate of 94%-110% with a relative standard deviation of 1.9%-3.7% (n = 4). The results obtained were compared with the reported FI-CL and high-performance liquid chromatography-ultraviolet methods, and the three methods did not differ significantly at the 95% confidence limit.

Advances in the Detection of Dithiocarbamate Fungicides: Opportunities for Biosensors

Dithiocarbamate fungicides (DTFs) are widely used to control various fungal diseases in crops and ornamental plants. Maximum residual limits in the order of ppb-ppm are currently imposed by legislation to prevent toxicity problems associated with excessive use of DTFs. The specific analytical determination of DTFs is complicated by their low solubility in water and organic solvents. This review summarizes the current analytical procedures used for the analysis of DTF, including chromatography, spectroscopy, and sensor-based methods and discusses the challenges related to selectivity, sensitivity, and sample preparation. Biosensors based on enzymatic inhibition demonstrated potential as analytical tools for DTFs and warrant further research, considering novel enzymes from extremophilic sources. Meanwhile, Raman spectroscopy and various sensors appear very promising, provided the selectivity issues are solved.

A review of recent developments based on chemiluminescence detection systems for pesticides analysis

Chemiluminescence is one of the most coveted methods for sensitive determination of pesticides in food and environmental samples. To date, many methods have been developed for qualitative and quantitative analysis of pesticides, ranging from traditional to advanced methods. This study outlines the progress in the conventional and advanced analytical methods, coupled to a chemiluminescence detection system, that are employed for the determination of pesticides in food and environmental samples. Different analytical methods including chromatographic methods, flow-based systems, and paper-based systems are reviewed in this paper. As well, new advances in the application of nanomaterials, aptamer, and molecularly imprinted polymers are highlighted. We also address the challenges and difficulties associated with these methods. Finally, we highlight the future direction in this active field of research.

Flow analysis with chemiluminescence detection: Recent advances and applications

This article highlights the most important developments in flow analysis with chemiluminescence (CL) detection, describing different flow systems that are compatible with CL detection, detector designs, commonly applied CL reactions and approaches to sample treatment. Recent applications of flow analysis with CL detection (focusing on outputs published since 2010) are also presented. Applications are classified by sample matrix, covering foods and beverages, environmental matrices, pharmaceuticals and biological fluids. Comprehensive tables are provided for each area, listing the specific sample matrix, CL reaction used, linear range, limit of detection and sample treatment for each analyte. Finally, recent and emerging trends in the field are also discussed.