Population and biomarker responses of Daphnia magna towards anticholinesterase exposures

Abstract

Context: Cholinesterase (ChE) had long been employed for revealing environmental existence of anticholinesterases, and β-N-acetylglucosaminidase (NAGase) is a newly developed biomarker of aquatic arthropods. Still, population consequences of ChE inhibition and the consequences in terms of NAGase remained unclear.

Objective: To quantify relationship between level of ChE and that of NAGase deliberated from chemical suppressed population of Daphnia magna.

Methods: A set of macrophyte-dominated systems were established indoor to test insecticide chlorpyrifos. Antibodies were developed for quantifying content of ChE in bodies and content of NAGase in media, which was achieved by indirect-competitive and indirect-noncompetitive enzyme-linked immunosorbent assay (ELISA), respectively.

Results: Lowest observed effect concentration (LOEC) of chlorpyrifos, as it was counted by actual concentrations, was 0.128, <0.011, 0.092, and 0.092 µg/L for population density, inherent activity of ChE, apparent activity of ChE, and content of NAGase, respectively. Corresponding to 0.90–0.48 U/µg declination in inherent activity of ChE, atrophy of −1.65 to 23% in population and that of −4.1 to 24.89% in NAGase was detected, respectively.

Conclusion: Population impact of an anticholinesterase could be predicted, with adequate accuracy, by either ChE or NAGase.

Keywords:

• Daphnia magna
• chlorpyrifos
• free-living NAGase
• somatic ChE
• polyclonal antibodies
• ELISA

PUBLIC INTEREST STATEMENT

Is it possible to announce dynamic of a population and impact of a chemical on that by status of a biomarker? To find an answer for that, a species of crustacean Daphnia magna was employed to test its responses in terms of population, somatic cholinesterase, and deliberated NAGase toward organophosphorus insecticide chlorpyrifos. Result indicated that population impact of an anticholinesterase could be predicted, with adequate accuracy, by either ChE or NAGase. Corresponding to 0.90–0.48 U/µg declination in inherent activity of ChE, atrophy of −1.65 to 23% in population and that of −4.1 to 24.89% in NAGase was detected, respectively, in this study.

Competing Interests

The authors declares no competing interests.

Disclosure statement

The authors report no declarations of interest.

Ethic statement

The D. magna is a species of zooplankton, and no animal welfare guideline has been available by now for this group of organisms. All the waste produced was stored and recycled according to the rules issued by Administrative Department of Laboratory and Equipment, Zhejiang University.

Cover Image

Source: Author.

Additional information

Funding

This work was supported by Natural Science Foundation of Zhejiang Province [No. LY17B070002].

Notes on contributors

Qianping Lang

Qianping Lang is a graduate student in Institute of Pesticide and Environmental Toxicology, College of Agriculture and Biotechnology, Zhejiang University. She works on biomarkers for quantifying population impact of a chemical.

Shaonan Li

Shaonan Li is a teaching staff in Institute of Pesticide and Environmental Toxicology, College of Agriculture and Biotechnology, Zhejiang University. Major concern of his group lies at ecological consequences of chemical exposure.