Survival strategies of Wuchang bream (Megalobrama amblycephala) juveniles for chronic ammonia exposure: Antioxidant defense and the synthesis of urea and glutamine
Autor: | Yuming Qiu, Wang Lin, Lingkai Wang, Xueyang Wu, Dapeng Li, Honghui Guo, Li Li, Liping Yang, Rong Tang, Dandan Zhang |
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Rok vydání: | 2019 |
Předmět: |
Fish Proteins
medicine.medical_specialty Antioxidant Physiology Health Toxicology and Mutagenesis medicine.medical_treatment Glutamine Glutathione reductase Cyprinidae 010501 environmental sciences Toxicology 01 natural sciences Biochemistry Superoxide dismutase chemistry.chemical_compound Ammonia Internal medicine medicine Animals Urea 0105 earth and related environmental sciences chemistry.chemical_classification biology Chemistry Glutathione peroxidase 04 agricultural and veterinary sciences Cell Biology General Medicine Glutathione biology.organism_classification Oxidative Stress Endocrinology Liver 040102 fisheries biology.protein 0401 agriculture forestry and fisheries Wuchang bream Water Pollutants Chemical |
Zdroj: | Comparative biochemistry and physiology. Toxicologypharmacology : CBP. 230 |
ISSN: | 1532-0456 |
Popis: | This study aimed to explore how Wuchang bream (Megalobrama amblycephala) survive and defend against the toxicity of ambient total ammonia nitrogen (0, 5, 10, 20 and 30 mg/L TA-N) during 30-day exposure. As a result, hepatic malondialdehyde and protein carbonylation as well as histopathological alterations increased with increasing TA-N level, which suggested that chronic ammonia exposure caused oxidative stress and damage in the liver of fish. Meanwhile, the activities of hepatic total superoxide dismutase (T-SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glucose 6-phosphate dehydrogenase (G6PD) as well as the mRNA expression of Cu/Zn sod, cat, gpx and g6pd were elevated significantly along with significant reduction of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH) (P 0.05). These results indicated that hepatic antioxidant responses were activated to alleviate oxidative damages induced by ammonia, in which lower-concentration ammonia only initiate SOD-CAT-GR-G6PDH defense and higher ammonia activated the SOD-CAT-GPx-GSH-GR-G6PDH antioxidant response. In addition, significant increases of serum urea and hepatic ammonia, urea, glutamine, arginase as well as glutamine synthetase were detected with the increase of TA-N (P 0.05), while serum ammonia levels kept stable (P 0.05). The present findings further revealed that ammonia could be detoxified directly into glutamine and urea in Wuchang bream to cope with ammonia exposure. In conclusion, under chronic ammonia exposure, enhanced hepatic antioxidant responses as well as increased urea and glutamine synthesis worked in combination to allow Megalobrama amblycephala to defend against environmental ammonia toxicity. |
Databáze: | OpenAIRE |
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