title: Determination of microcystin-LR and its metabolites in snail (Bellamya aeruginosa), shrimp (Macrobrachium nipponensis) and silver carp (Hypophthalmichthys molitrix) from Lake Taihu, China.
abstract: This paper describes seasonal changes of microcystin-LR (MC-LR) and its glutathione (MC-LR-GSH) and cysteine conjugates (MC-LR-Cys) in three aquatic animals--snail (Bellamya aeruginosa), shrimp (Macrobrachium nipponensis) and silver carp (Hypophthalmichthys molitrix) collected from Lake Taihu, China. MC-LR, MC-LR-GSH, and MC-LR-Cys were determined by liquid chromatography electrospray ionization mass spectrum (LC-ESI-MS). The mean MC-LR concentrations in the hepatopancreas of snail and shrimp and liver of silver carp were 6.61, 0.24, and 0.027 microg g(-1) dry weight (DW), respectively; while the average MC-LR-Cys concentrations were 0.50, 0.97, and 5.72 microg g(-1) DW, respectively. MC-LR-GSH was usually not detectable in these samples. The above results suggest that: (1) in aquatic animals, especially fish, the main excretion form of MC-LR could be MC-LR-Cys, but not MC-LR-GSH, whereas MC-LR-Cys might play an important role in detoxication of MC-LR and (2) that efficiency of MC-LR-Cys formation differs among species. The main detoxication pathway of MC-LR in aquatic animals is suggested as follows: when MC-LR enters into liver/hepatopancreas, it firstly conjugates with polypeptide or protein (including GSH, PP-1 and 2A) containing Cys residues, perhaps also some free cysteine; subsequently, MC-LR-Cys is degraded from these polypeptide or protein; and finally is excreted from animals by the compound of MC-LR-Cys.
authors.affiliation: Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
authors.forename: Dawen
authors.initials: D
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Xie
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Dai
authors.forename: Tong
authors.initials: T
authors.lastname: Qiu
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Liu
authors.forename: Gaodao
authors.initials: G
authors.lastname: Liang
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002347:Carps / Q000378:metabolism*; D002681:China; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring; D008387:Marine Toxins; D052998:Microcystins / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D033541:Palaemonidae / Q000378:metabolism*; D012621:Seasons; D012908:Snails / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; C057862:cyanoginosin LR