Agricultural pesticide handlers are at an elevated risk for overexposure to organophosphate OP pesticides, but symptoms can be difficult to recognise, making biomarkers invaluable for diagnosis. Occupational monitoring programmes for cholinesterase depression generally rely on measuring activity of either of the two common blood cholinesterases which serve as proxy measurements for nervous-system acetylcholinesterase activity: These biomarkers, however, may be affected differentially by some OPs and the relationship between them has not been well characterised.
Received Jan 3; Accepted Feb Copyright Santos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
Abstract Over the last decades the inhibition of plasma cholinesterase ChE activity has been widely used as a biomarker to diagnose organophosphate and carbamate exposure. Plasma ChE activity is a useful and non-invasive method to monitor bird exposure to anticholinesterase compounds; nonetheless several studies had shown that the ChE form s present in avian plasma may vary greatly among species.
In order to support further biomonitoring studies and provide reference data for wildlife risk-assessment, plasma cholinesterase of the northern gannet Morus bassanusthe white stork Ciconia ciconia and the grey heron Ardea cinerea were characterized using three substrates acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide and three ChE inhibitors eserine sulphate, BWC51, and iso-OMPA.
Additionally, the range of ChE activity that may be considered as basal levels for non-exposed individuals was determined. The results suggest that in the plasma of the three species studied the main cholinesterase form present is butyrylcholinesterase BChE.
Plasma BChE activity in non-exposed individuals was 0. These results are crucial for the further use of plasma BChE activity in these bird species as a contamination bioindicator of anti-cholinesterase agents in both wetland and marine environments.
Our findings also underscore the importance of plasma ChE characterization before its use as a biomarker in biomonitoring studies with birds. Introduction Cholinesterase ChE activity has been routinely used as a biomarker to diagnose exposure to anticholinesterase compounds such as organophosphate OP and carbamate CB pesticides.
These pesticides are broadly used to control insect pests and disease vectors; nonetheless, they can be extremely toxic to non-target organisms like mammals and birds . They act by inhibiting the activity of cholinesterases, which causes an over accumulation of acetylcholine at the synapses and consequent disruption of nerve function, leading to subsequent physiologic disorders and ultimately death .
In addition to OPs and CBs, other environmental contaminants such as metals, detergents and petroleum-derived products have been found to generate similar inhibitory effects . Serum or plasma has been broadly used to measure ChE activity as a non-invasive method to monitor exposure of wildlife to pesticides in the field due to its sensitivity to ChE-inhibiting compounds .
Nonetheless, its use requires the characterization of the enzyme form s present in the tissue assayed and the determination of the normal range of activity in non-exposed individuals . Two enzymes form the family of cholinesterases: Both catalyze the hydrolysis of the neurotransmitter acetylcholine, but differ in substrate specificity and inhibitor susceptibility  ; tissue distribution can also vary, depending on the organism measured.
AChE is predominantly found in the neuromuscular junctions and central nervous system, playing a key-role in the cholinergic neurotransmission, while BChE is mainly found in serum and liver, but its primary physiological role remains unknown .
Regarding wildlife exposure to environmental contaminants, waterbirds, such as wading birds and seabirds, are useful indicators of environmental variation upon short and long temporal scales . Wading birds are primarily indicators of wetland quality as they can occupy a wide variety of foraging niches, including agricultural ponds, which makes them often non-target species to OP and CB exposure through ingestion and dermal contact .
In the case of seabirds, they are widely used to monitor the occurrence and ecological impacts of contaminants such as oil and mercury in the marine environment .
All these possible exposures may lead into an impairment of ChE activities in birds, and therefore biomarkers like this may be also a useful indicator to detect contamination in birds' habitats. In order to use plasma ChE as a biomarker of exposure in three Portuguese native bird species, the main aim of this study was to: Materials and Methods Sample collection All the species of birds used to characterize plasma ChE were adult individuals inhabiting the Gaia Biological Park, a nature reserve located in Avintes Porto, Portugal.
Bassanus were in captivity. The disturbance stress caused by the animal handling was minimized by limiting the visit length, avoiding any sampling during extreme weather conditions e.
Sample preparation and ChE determinations Plasma samples were diluted in phosphate buffer 0. Cholinesterase characterization Plasma ChE was characterized by testing the substrate preferences of the enzymes and their sensitivity to selective inhibitors.A remote monitoring system includes an on-body network of sensors and at least on analysis device controlled by a hub.
The sensors monitor human physiology, activity and environmental conditions. The monitoring system includes a data classifier to take sensor input to determine a condition of the person wearing the remote monitoring system. USACEHR Technical Report: An Evaluation of Blood Cholinesterase Testing Methods for Military Health Surveillance Abstract Blood cholinesterase (ChE) testing is .
ELECTROCHEMICAL SENSORS FOR ENVIRONMENTAL MONITORING: A REVIEW OF RECENT TECHNOLOGY by JOSEPH WANG of environmental monitoring (depending on the nature of the analyte, the character of the sample matrix, and cholinesterase, tyrosinase, or .
Cholinesterase activity was inversely related to fish weight. Muscle ChE was comprised of both acetylcholinesterase and pseudocholinesterase. In July, fish from two sites (A and B) had significantly lower (∼30%) ChE activities than fish from all but one of the other sites.
The use of cholinesterase and carboxylesterase activities from Mytilus galloprovincialis in pollution monitoring Article in Environmental Toxicology and Chemistry 16(10) - · October. The Use of Cholinesterase Activity in This study investigated the occurrence and levels of neurotoxic contamination in UK estuaries by the determination of cholinesterase (ChE) activity in the muscle of the The use of reactivation techniques could be of particular use in environmental monitoring especially when a suitable control site.