B-esterase (BChE: butyrylcholinesterase and CbE: carboxylesterase) and glutathione S-transferase (GST) activity were measured in the plasma of Chaunus schneideri collected in rice fields and surrounding environments and in a reference pristine forest. The chemical criterion based on in-vitro reactivation of BChE activity using pyridine-2-aldoxime methochloride (2-PAM) was also determined. Mean values of plasma BchE, CbE, and GST activity for samples from agricultural areas were different from those for samples from pristine forest. Plasma samples from the two agricultural areas showed positive reactivation of BChE activity after incubation with 2-PAM. Based on our experimental evidence we suggest B-esterases and gluthatione S-transferases can be used in field monitoring as biomarkers of exposure of wildlife to pesticides, because the analysis in non-destructive and is sensitive to anti-ChE agrochemicals. Chemical reactivation of BChE is also a complementary method for assessing the effects of pesticides on toads inhabiting rice fields. Further studies are urgently needed to investigate adverse effects of massive exposure to pesticides experienced by native populations of anurans.
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http://dx.doi.org/10.1007/s10646-007-0154-0 | DOI Listing |
Bioorg Chem
December 2024
University of Hradec Kralove, Faculty of Science, Department of Chemistry, Rokitanskeho 62, 500 03 Hradec Kralove, Czech Republic; University Hospital in Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05 Hradec Kralove, Czech Republic. Electronic address:
Mono-quaternary pyridinium oximes derived from K-oximes K027, K048 and K203 were designed, synthesized and evaluated for the reactivation of organophosphate-inhibited cholinesterases. The incorporation of the halogen atoms to the structure decreased the pK value of the oxime group resulting in an increased formation of oximate necessary for reactivation. The stability and pK values were found to be similar to analogous bis-quaternary compounds.
View Article and Find Full Text PDFBiomolecules
June 2024
Division of Toxicology, Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb, Croatia.
New furan, thiophene, and triazole oximes were synthesized through several-step reaction paths to investigate their potential for the development of central nervous systems (CNS)-active and cholinesterase-targeted therapeutics in organophosphorus compound (OP) poisonings. Treating patients with acute OP poisoning is still a challenge despite the development of a large number of oxime compounds that should have the capacity to reactivate acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The activity of these two enzymes, crucial for neurotransmission, is blocked by OP, which has the consequence of disturbing normal cholinergic nerve signal transduction in the peripheral and CNS, leading to a cholinergic crisis.
View Article and Find Full Text PDFBioorg Chem
September 2024
University of Hradec Kralove, Faculty of Science, Department of Chemistry, Rokitanskeho 62, 500 03 Hradec Kralove, Czech Republic; University Hospital in Hradec Kralove, Biomedical Research Centre, Sokolska 581, 500 05 Hradec Kralove, Czech Republic. Electronic address:
In this review, the current progress in the research and development of butyrylcholinesterase (BChE) reactivators is summarised and the advantages or disadvantages of these reactivators are critically discussed. Organophosphorus compounds such as nerve agents (sarin, tabun, VX) or pesticides (chlorpyrifos, diazinon) cause irreversible inhibition of acetylcholinesterase (AChE) and BChE in the human body. While AChE inhibition can be life threatening due to cholinergic overstimulation and crisis, selective BChE inhibition has presumably no adverse effects.
View Article and Find Full Text PDFArch Toxicol
September 2024
University of Hradec Kralove, Faculty of Science, Department of Chemistry, Rokitanskeho 62, 500 03, Hradec Kralove, Czech Republic.
Six novel brominated bis-pyridinium oximes were designed and synthesized to increase their nucleophilicity and reactivation ability of phosphorylated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Their pK was valuably found lower to parent non-halogenated oximes. Stability tests showed that novel brominated oximes were stable in water, but the stability of di-brominated oximes was decreased in buffer solution and their degradation products were prepared and characterized.
View Article and Find Full Text PDFBiomolecules
May 2024
Division of Toxicology, Institute for Medical Research and Occupational Health, 10001 Zagreb, Croatia.
Olesoxime, a cholesterol derivative with an oxime group, possesses the ability to cross the blood-brain barrier, and has demonstrated excellent safety and tolerability properties in clinical research. These characteristics indicate it may serve as a centrally active ligand of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), whose disruption of activity with organophosphate compounds (OP) leads to uncontrolled excitation and potentially life-threatening symptoms. To evaluate olesoxime as a binding ligand and reactivator of human AChE and BChE, we conducted kinetic studies with the active metabolite of insecticide parathion, paraoxon, and the warfare nerve agents sarin, cyclosarin, tabun, and VX.
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