Biochemical responses as early and reliable biomarkers of organophosphate and carbamate pesticides intoxication: A systematic literature review

Molecular docking and molecular dynamics simulations revealed interaction mechanism of acetylcholinesterase with organophosphorus pesticides and their alternatives

Organophosphate pesticides (OPs) are widely used in agricultural fields and can inhibit the activity of human acetylcholinesterase (hAChE) by covalently binding to serine at the enzyme's active site. However, the molecular recognition mechanisms beyond their covalent binding remain unclear. This study employed molecular docking along with molecular dynamics simulations (MD) to investigate four representative OPs, Phosphamidon, Monocrotophos, Dichlorvos, and Trichlorfon, as well as two potential alternatives Magnolol (MAG) and Honokiol (HON), to understand the conformational change of hAChE and its molecular recognition mechanism. The results indicate that, in addition to these OPs, the selected substitutes also induce various changes in the internal structure of hAChE, especially interactions with key residues around Trp86, Tyr124, Tyr337, and His447. Energy calculations utilizing MM-GBSA and SIE methods further reveal the critical role of van der Waals interactions in hAChE's interaction with these OPs and their substitutes. It is worth noting that two potential pesticide alternatives MAG and HON differ in structure from OPs at the benzene ring and hydroxyl positions, resulting in their weaker binding energy with hAChE. Furthermore, the accuracy of simulation models was validated through in silico site-directed mutagenesis based on the key residues. By identifying dynamic structural changes and energy signatures, this study provides valuable information for finding safer alternatives to OPs.

Exposure to an environmentally relevant concentration of chlorpyrifos induces transcriptional changes and neurotoxicity in Poecilia gillii without clear behavioral effects

Overusing chlorpyrifos (CPF) in tropical countries such as Costa Rica poses a potential risk to freshwater ecosystems. This study investigated the effects of transient exposure to an environmentally relevant CPF concentration on the native fish species Poecilia gillii, employing a comprehensive approach that evaluated multiple levels of biological organization. Using RT-qPCR, we quantified transcript changes in genes involved in various biological processes, including inflammation and apoptosis; annexin A1 (anxa1b), cytokine regulation; cytokine-inducible SH2-containing protein (cish), redox reactions; NADH oxidoreductase subunit A2 (ndufa2), protein translocation; Sec61 gamma subunit (sec61g), and biotransformation; glutathione S-transferase rho (gstr). Additionally, we measured biochemical biomarkers such as phase I; 7-ethoxyresorufin-O-deethylase (EROD) and phase II; glutathione S-transferase (GST) biotransformation enzymes, oxidative stress markers; catalase (CAT) and lipid peroxidation (LPO), and conducted behavioral tests to assess swimming fitness and antipredator reactions. Neurotoxicity was assessed by measuring brain and muscle tissue cholinesterase (ChE) activity. Following 48 h of exposure to 5.5 µg/L CPF, we observed significant downregulation of the sec61g and gstr genes, decreased CAT activity, and neurotoxic effects, as indicated by reduced ChE activity in muscle. Although no significant behavioral changes were detected, our results suggest that short-term exposure to environmentally relevant CPF concentrations can disrupt gene expression, compromising biotransformation and protein synthesis in P. gillii juveniles. Moreover, the observed neurotoxicity, which is consistent with the mechanism of action of CPF, may lead to subtle behavioral changes. This study provides evidence of the sublethal effects of CPF on nontarget organisms, highlighting the importance of considering gene expression changes when assessing CPF toxicity.

Organophosphate Poisoning: Review of Prognosis and Management

The high annual mortality rate of organophosphorus (OP) poisoning indicates that the treatment is mostly ineffective in this regard. It has been suggested to add calcium channel blocking (CCB) drugs or magnesium sulfate (MgSO4) to normal care to decrease the release of acetylcholine (ACh) at the cholinergic synapse. Moreover, the diagnosis of OP poisoning is chiefly based on clinical evidence. Oximes and atropine are the recognized antidotes of OP. However, low-priced medications such as MgSO4 and sodium bicarbonate (NaHCO3), as well as novel adjunct therapies, have been introduced recently. Furthermore, antioxidants are recommended for managing OP poisoning. In addition, hemoperfusion, fresh frozen plasma (FFP), and K-oximes are a number of innovative management modalities that deserve further evaluation. However, prevention seems to be the most effective management modality in this respect. Therefore, this study aimed to briefly discuss the controversies in OP poisoning management and present recent advances in its management and prognosis. The results of this study revealed that multiple factors including type of exposure, acetylcholinesterase (AChE) plasma level, time of hospitalization, and severity confirming OP poisoning should be considered to provide the best treatment strategy.

Pesticides impacts on human health and the environment with their mechanisms of action and possible countermeasures

Pesticides are chemical constituents used to prevent or control pests, including insects, rodents, fungi, weeds, and other unwanted organisms. Despite their advantages in crop production and disease management, the use of pesticides poses significant hazards to the environment and public health. Pesticide elements have now perpetually entered our atmosphere and subsequently contaminated water, food, and soil, leading to health threats ranging from acute to chronic toxicities. Pesticides can cause acute toxicity if a high dose is inhaled, ingested, or comes into contact with the skin or eyes, while prolonged or recurrent exposure to pesticides leads to chronic toxicity. Pesticides produce different types of toxicity, for instance, neurotoxicity, mutagenicity, carcinogenicity, teratogenicity, and endocrine disruption. The toxicity of a pesticide formulation may depend on the specific active ingredient and the presence of synergistic or inert compounds that can enhance or modify its toxicity. Safety concerns are the need of the hour to control contemporary pesticide-induced health hazards. The effectiveness and implementation of the current legislature in providing ample protection for human health and the environment are key concerns. This review explored a comprehensive summary of pesticides regarding their updated impacts on human health and advanced safety concerns with legislation. Implementing regulations, proper training, and education can help mitigate the negative impacts of pesticide use and promote safer and more sustainable agricultural practices.

Antimicrobial and antibiofilm properties of selenium-chitosan-loaded salicylic acid nanoparticles for the removal of emerging contaminants from bacterial pathogens

In this study salicylic acid loaded containing selenium nanoparticles was synthesized and called SA@CS-Se NPs. the chitosan was used as a natural stabilizer during the synthesis process. Fourier transforms infrared spectroscopy (FTIR), Powder X-ray diffraction (XRD), field emission electron microscopy (FESEM), and transmission electron microscopy (TEM) were used to describe the physicochemical characteristics of the SA@CS-Se NPs. The PXRD examination revealed that the grain size was around 31.9 nm. TEM and FESEM techniques showed the spherical shape of SA@CS-Se NPs. Additionally, the analysis of experiments showed that SA@CS-Se NPs have antibacterial properties against 4 ATCC bacteria; So that with concentrations of 75, 125, 150, and 100 µg/ml, it inhibited the biofilm formation of Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus respectively. Also, at the concentration of 300 µg/ml, it removed 22.76, 23.2, 10.62, and 18.08% biofilm caused by E. coli, P. aeruginosa, B. subtilis, and S. aureus respectively. The synthesized SA@CS-Se NPs may find an application to reduce the unsafe influence of pathogenic microbes and, hence, eliminate microbial contamination.