title: First report of aphantoxins in China--waterblooms of toxigenic Aphanizomenon flos-aquae in Lake Dianchi.
abstract: The oligohaline cyanobacterium Aphanizomenon flos-aquae (L.) Ralfs (A. flos-aquae) has been reported in several countries to produce paralytic shellfish poisons (PSPs) or protracted toxic effects. In the past years, A. flos-aquae blooms have occurred annually in the eutrophic Lake Dianchi (300 km(2) in area, located in southwestern China). Material from natural blooms dominated by A. flos-aquae was collected and lyophilized. Acute toxicity testing was performed by mouse bioassay using extracts from the lyophilized material. Clear symptoms of PSPs intoxications were observed. To confirm the production of PSPs, a strain of A. flos-aquae (DC-1) was isolated and maintained in culture. Histopathological effects were studied by examining the organ damages using transmission electron microscopy (TEM). Slight hepatocytic damage with swollen mitochondria was found. The ultrastructural pulmonary lesions were characterized by distortied nuclei and indenting of karyotheca, together with degeneration and tumefaction of mitochondria and endoplasmic reticulum. Control animals injected with acetic acid did not exhibit histopathological damage in any organ. Toxic effects of cultured algal cells on enzymatic systems in the mouse were studied using sublethal doses of extracts. Significant glutathione-S-transferase (GST) and lactate dehydrogenase (LDH) increases, together with decrease of the glutathione (GSH) level, were measured. These results indicated a potential role of PSPs intoxicating and metabolizing in the test animals. HPLC-FLD and LC/MS analysis of extracts from cultured material demonstrated the PSP toxins produced by A. flos-aquae bloom. To the best of our knowledge, this is the first study reporting chemically and toxicologically confirmed PSP toxins related to A. flos-aquae in China.
authors.affiliation: Institute of Hydrobiology, State Key Laboratory of Freshwater Ecology and Biotechnology, the Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Dunhai
authors.initials: D
authors.lastname: Li
authors.forename: Yinwu
authors.initials: Y
authors.lastname: Shen
authors.forename: Genbao
authors.initials: G
authors.lastname: Li
authors.forename: Yongding
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D046890:Aphanizomenon / Q000502:physiology*; D001427:Bacterial Toxins / Q000737:chemistry / Q000633:toxicity*; D001681:Biological Assay; D002466:Cell Nucleolus / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D002681:China; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D005068:Eutrophication / Q000502:physiology*; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology*; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000648:ultrastructure; D008297:Male; D008387:Marine Toxins / Q000737:chemistry / Q000633:toxicity*; D013058:Mass Spectrometry; D051379:Mice; D008928:Mitochondria / Q000648:ultrastructure
chemical_list: D001427:Bacterial Toxins; D008387:Marine Toxins; C034321:aphantoxin; D007770:L-Lactate Dehydrogenase; D005982:Glutathione Transferase; D005978:Glutathione