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Experimental measurements for the effect of dilution procedure in blood esterases as animals biomarker for exposure to OP compounds.

Abass KS - Biomed Res Int (2014)

Bottom Line: It is unclear from the literature whether it is the carboxylesterase affinity for the organophosphate and/or the number of carboxylesterase molecules that is the dominant factor in determining the protective potential of carboxylesterase.Point estimates (concentrations calculated to produce 20, 50, and 80% inhibition) were compared across conditions and served as a measure of esterase-mediated detoxification.Results with well-known inhibitors (malathion) were in agreement with the literature, serving to support the use of this assay.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Nursing Sciences, College of Nursing, University of Kirkuk, Kirkuk, Iraq.

ABSTRACT
Organophosphate compounds can bind to carboxylesterase, which may lower the concentration of organophosphate pesticides at the target site enzyme, cholinesterase. It is unclear from the literature whether it is the carboxylesterase affinity for the organophosphate and/or the number of carboxylesterase molecules that is the dominant factor in determining the protective potential of carboxylesterase. The fundamental dilutions and kinetic effects of esterase enzyme are still poorly understood. This study aims to confirm and extend our current knowledge about the effects of dilutions on esterases activities in the blood for birds with respect to protecting the enzyme from organophosphate inhibition. There was significantly higher esterases activities in dilution 1 : 10 in the all blood samples from quail, duck, and chick compared to other dilutions (1 : 5, 1 : 15, 1 : 20, and 1 : 25) in all cases. Furthermore, our results also pointed to the importance of estimating different dilutions effects prior to using in birds as biomarker tools of environmental exposure. Concentration-inhibition curves were determined for the inhibitor in the presence of dilutions 1 : 5, 1 : 10, plus 1 : 15 (to stimulate carboxylesterase). Point estimates (concentrations calculated to produce 20, 50, and 80% inhibition) were compared across conditions and served as a measure of esterase-mediated detoxification. Results with well-known inhibitors (malathion) were in agreement with the literature, serving to support the use of this assay. Among the thiol-esters dilution 1 : 5 was observed to have the highest specificity constant (k(cat)/K(m)), and the K m and k cat values were 176 μM and 16,765 s(-1), respectively, for S-phenyl thioacetate ester, while detected in dilution 1: 15 was the lowest specificity constant (k(cat)/K(m)), and the Km and k cat values were 943 μM and 1154 s(-1), respectively, for acetylthiocholine iodide ester.

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Related in: MedlinePlus

Esterase enzyme activities in erythrocyte diluted for quail (a), duck (b), and chick (c). Key to the figures is listed under Figure 1.
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fig2: Esterase enzyme activities in erythrocyte diluted for quail (a), duck (b), and chick (c). Key to the figures is listed under Figure 1.

Mentions: The effect of dilutions on CbE and ChE activities was determined in serum, plasma, and erythrocyte for quail, duck, and chick as described in above section of Materials and Methods (Figures 1–3). CbE and ChE activities in dilution 1 : 10 observed highest activity in the plasma, serum, and erythrocyte for quail, duck, and chick (Figures 1–3). It was found that plasma CbE was significant (P < 0.05) in dilution 1 : 25 among other dilutions for quail and chick (Figures 1(a) and 1(c)). Blood plasma from the ChE activity in blood from the plasma was significantly different (P < 0.05) in dilution 1 : 25 among other dilutions for quail and duck (Figures 1(a) and 1(b)) and in dilution 1 : 10 among other dilutions for chick (Figure 1(c)). The plasma activities of CbE ranged between 70.1 and 178.1 nmol min−1 mL−1 for quail, between 99.9 and 196.7 nmol min−1 mL−1 for duck, and between 99.6 and 387.5 nmol min−1 mL−1 for chick samples across different dilutions, while for plasma ChE ranged between 83.3 and 172.3 nmol min−1 mL−1 for quail, between 119.7 and 305.3 nmol min−1 mL−1 for duck, and between 307.7 and 590.7 nmol min−1 mL−1 for chick samples across different dilutions (Figures 1(a)–1(c)). There was significance (P < 0.05) in serum CbE within dilution 1 : 25 among other dilutions used for quail and chick (Figures 2(a) and 2(c)), while serum CbE was not significant (P > 0.05) between dilution 1 : 20 and dilution 1 : 25 for duck (Figure 2(b)). ChE activity was a significantly different (P < 0.05) between dilution 1 : 10 and dilution 1 : 15 with other dilutions used for quail (Figure 2(a)), while in duck it was seen as not significant (P > 0.05) between dilution 1 : 20 and dilution 1 : 25 (Figure 2(b)), whereas for chick was significant (P < 0.05) between dilution 1 : 25 among other dilutions (Figure 2(c)). The serum activities of CbE ranged between 80.2 and 180.6 nmol min−1 mL−1 for quail, between 58.1 and 387.6 nmol min−1 mL−1 for duck, and between 62.9 and 463.1 nmol min−1 mL−1 for chick samples across different dilutions, whereas for serum ChE ranged between 211.1 and 420.3 nmol min−1 mL−1 for quail, between 82.3 and 350.2 nmol min−1 mL−1 for duck, and between 297.3 and 708.4 nmol min−1 mL−1 for chick samples across different dilutions (Figures 2(a)–2(c)). The enzyme activity in the serum blood at the higher dilution ratio declined faster than that of samples at lower dilution ratio.


Experimental measurements for the effect of dilution procedure in blood esterases as animals biomarker for exposure to OP compounds.

Abass KS - Biomed Res Int (2014)

Esterase enzyme activities in erythrocyte diluted for quail (a), duck (b), and chick (c). Key to the figures is listed under Figure 1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016918&req=5

fig2: Esterase enzyme activities in erythrocyte diluted for quail (a), duck (b), and chick (c). Key to the figures is listed under Figure 1.
Mentions: The effect of dilutions on CbE and ChE activities was determined in serum, plasma, and erythrocyte for quail, duck, and chick as described in above section of Materials and Methods (Figures 1–3). CbE and ChE activities in dilution 1 : 10 observed highest activity in the plasma, serum, and erythrocyte for quail, duck, and chick (Figures 1–3). It was found that plasma CbE was significant (P < 0.05) in dilution 1 : 25 among other dilutions for quail and chick (Figures 1(a) and 1(c)). Blood plasma from the ChE activity in blood from the plasma was significantly different (P < 0.05) in dilution 1 : 25 among other dilutions for quail and duck (Figures 1(a) and 1(b)) and in dilution 1 : 10 among other dilutions for chick (Figure 1(c)). The plasma activities of CbE ranged between 70.1 and 178.1 nmol min−1 mL−1 for quail, between 99.9 and 196.7 nmol min−1 mL−1 for duck, and between 99.6 and 387.5 nmol min−1 mL−1 for chick samples across different dilutions, while for plasma ChE ranged between 83.3 and 172.3 nmol min−1 mL−1 for quail, between 119.7 and 305.3 nmol min−1 mL−1 for duck, and between 307.7 and 590.7 nmol min−1 mL−1 for chick samples across different dilutions (Figures 1(a)–1(c)). There was significance (P < 0.05) in serum CbE within dilution 1 : 25 among other dilutions used for quail and chick (Figures 2(a) and 2(c)), while serum CbE was not significant (P > 0.05) between dilution 1 : 20 and dilution 1 : 25 for duck (Figure 2(b)). ChE activity was a significantly different (P < 0.05) between dilution 1 : 10 and dilution 1 : 15 with other dilutions used for quail (Figure 2(a)), while in duck it was seen as not significant (P > 0.05) between dilution 1 : 20 and dilution 1 : 25 (Figure 2(b)), whereas for chick was significant (P < 0.05) between dilution 1 : 25 among other dilutions (Figure 2(c)). The serum activities of CbE ranged between 80.2 and 180.6 nmol min−1 mL−1 for quail, between 58.1 and 387.6 nmol min−1 mL−1 for duck, and between 62.9 and 463.1 nmol min−1 mL−1 for chick samples across different dilutions, whereas for serum ChE ranged between 211.1 and 420.3 nmol min−1 mL−1 for quail, between 82.3 and 350.2 nmol min−1 mL−1 for duck, and between 297.3 and 708.4 nmol min−1 mL−1 for chick samples across different dilutions (Figures 2(a)–2(c)). The enzyme activity in the serum blood at the higher dilution ratio declined faster than that of samples at lower dilution ratio.

Bottom Line: It is unclear from the literature whether it is the carboxylesterase affinity for the organophosphate and/or the number of carboxylesterase molecules that is the dominant factor in determining the protective potential of carboxylesterase.Point estimates (concentrations calculated to produce 20, 50, and 80% inhibition) were compared across conditions and served as a measure of esterase-mediated detoxification.Results with well-known inhibitors (malathion) were in agreement with the literature, serving to support the use of this assay.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Nursing Sciences, College of Nursing, University of Kirkuk, Kirkuk, Iraq.

ABSTRACT
Organophosphate compounds can bind to carboxylesterase, which may lower the concentration of organophosphate pesticides at the target site enzyme, cholinesterase. It is unclear from the literature whether it is the carboxylesterase affinity for the organophosphate and/or the number of carboxylesterase molecules that is the dominant factor in determining the protective potential of carboxylesterase. The fundamental dilutions and kinetic effects of esterase enzyme are still poorly understood. This study aims to confirm and extend our current knowledge about the effects of dilutions on esterases activities in the blood for birds with respect to protecting the enzyme from organophosphate inhibition. There was significantly higher esterases activities in dilution 1 : 10 in the all blood samples from quail, duck, and chick compared to other dilutions (1 : 5, 1 : 15, 1 : 20, and 1 : 25) in all cases. Furthermore, our results also pointed to the importance of estimating different dilutions effects prior to using in birds as biomarker tools of environmental exposure. Concentration-inhibition curves were determined for the inhibitor in the presence of dilutions 1 : 5, 1 : 10, plus 1 : 15 (to stimulate carboxylesterase). Point estimates (concentrations calculated to produce 20, 50, and 80% inhibition) were compared across conditions and served as a measure of esterase-mediated detoxification. Results with well-known inhibitors (malathion) were in agreement with the literature, serving to support the use of this assay. Among the thiol-esters dilution 1 : 5 was observed to have the highest specificity constant (k(cat)/K(m)), and the K m and k cat values were 176 μM and 16,765 s(-1), respectively, for S-phenyl thioacetate ester, while detected in dilution 1: 15 was the lowest specificity constant (k(cat)/K(m)), and the Km and k cat values were 943 μM and 1154 s(-1), respectively, for acetylthiocholine iodide ester.

Show MeSH
Related in: MedlinePlus