Urea Excretion and Arginase Activity as New Biomarkers for Nitrite Stress in Freshwater Aquatic Animals
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Dipartimento di Scienze e Tecnologie, Università degli Studi di Napoli Parthenope, Via Acton n. 38, I-80133 Napoli, Italy
2
Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, Via Cinthia, I-80126 Napoli, Italy
*
Author to whom correspondence should be addressed.
Academic Editors: Laura Guimarães and Carlos Gravato
Water 2021, 13(24), 3521; https://doi.org/10.3390/w13243521
Received: 28 October 2021
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Revised: 5 December 2021
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Accepted: 6 December 2021
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Published: 9 December 2021
(This article belongs to the Special Issue Biomarkers: An Integrative Useful Tool for Ecotoxicolgy and Biomonitoring)
Background: In recent years, the concern has been growing on increasing aquatic nitrite levels due to anthropogenic activities. Crustaceans and fish easily uptake nitrite via the chloride uptake system of gills. High nitrite body levels may interfere with nitric oxide (NO) production by nitric oxide synthase (NOS). The arginase, which catalyzes arginine conversion to ornithine and urea, is central to NO homeostasis. In vivo, changes in the arginase activity alter urea body levels and urea excretion and modulate NOS by altering arginine availability for NO synthesis. Excess arginase activity may uncouple NOS and induce oxidative stress. Methods: We tested muscle arginase activity and urea excretion in two fish species, zebrafish and convict cichlid, and the crustacean Yamato shrimp, under sub-lethal nitrite stress. Results: Exposure to nitrite (2 mM in the fish, 1 mM in the shrimp) significantly increased blood nitrite concentration in all species. Concomitantly, nitrite stress significantly increased arginase activity, urea excretion, and urea levels in the blood. In Yamato shrimp, urea levels also increased in muscle. Conclusion: Our results agree with the hypothesis that nitrite stress affects NO homeostasis by arginase stimulation and urea excretion. These parameters might function as markers of sub-lethal nitrite stress in freshwater fish and crustaceans.
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Keywords:
nitrite; arginase; nitric oxide; nitric oxide synthase; urea excretion; Danio rerio; Amatitlania nigrofasciata; Caridina multidentata
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MDPI and ACS Style
Napolitano, G.; Fasciolo, G.; Agnisola, C.; Venditti, P. Urea Excretion and Arginase Activity as New Biomarkers for Nitrite Stress in Freshwater Aquatic Animals. Water 2021, 13, 3521. https://doi.org/10.3390/w13243521
AMA Style
Napolitano G, Fasciolo G, Agnisola C, Venditti P. Urea Excretion and Arginase Activity as New Biomarkers for Nitrite Stress in Freshwater Aquatic Animals. Water. 2021; 13(24):3521. https://doi.org/10.3390/w13243521
Chicago/Turabian StyleNapolitano, Gaetana, Gianluca Fasciolo, Claudio Agnisola, and Paola Venditti. 2021. "Urea Excretion and Arginase Activity as New Biomarkers for Nitrite Stress in Freshwater Aquatic Animals" Water 13, no. 24: 3521. https://doi.org/10.3390/w13243521
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