Crude extract of cyanobacteria (Radiocystis fernandoi, strain R28) induces liver impairments in fish

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Paulino, M. G. ; Tavares, D. ; Bieczynski, F. ; Pedrao, P. G. ; Souza, N. E. S. ; Sakuragui, M. M. ; Luquet, C. M. ; Terezan, A. P. ; Fernandes, J. B. ; Giani, A. ; Fernandes, M. N.

• Document type: Journal article
• Source: AQUATIC TOXICOLOGY; v. 182, p. 91-101, JAN 2017.
• Web of Science Citations: 6

Abstract

Radiocystis fernandoi R28 strain is a cyanobacterium which produces mostly the RR and YR microcystin variants (MC -RR and MC-YR, respectively). The effects of crude extract of the R. fernandoi strain R28 were evaluated on the protein phosphatases and on the structure and ultrastructure of the liver of the Neotropical fish, Hoplias malabaricus, after acute and subchronic exposure. Concomitantly, the accumulation of the majority of MCs was determined in the liver and muscle. The fish were exposed to 120.60 MC-RR+MC-LR kg-fish(-1) (= 100 mu g MC-LReq kg-fish(-1)) for 12 and 96 h (one single dose, acute exposure) and 30 days (one similar dose every 72 h, subchronic exposure). MCs did not accumulate in the muscle but, in the liver, MC-YR accumulated after acute exposure and MC -RR and MC-YR accumulation occurred after subchronic exposure. Protein phosphatase 2A (PP2A) activity was inhibited only after subchronic exposure. Acute exposure induced liver hyperemia, hemorrhage, changes in hepatocytes and cord-like disorganization. At the ultrastructural level, the decreasing of glycogen and lipid levels, the swelling of mitochondria and whirling of endoplasmic reticulum suggested hepatocyte necrosis. Subchronic exposure resulted in a complete disarrangement of cord-like hepatocytes, some recovery of mitochondria and whirling endoplasmic reticulum and extensive connective tissues containing fibrous materials in the liver parenchyma. Despite microcystin toxicity and liver alterations, no tumor was induced by MCs. In conclusion, the increased algal mass of R. fernandoi in tropical freshwater, producing mainly MC -RR and MC-YR variants, results in fish liver impairments. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/00728-1 - Effects of microcystins present in the crude extract of cyanobacterium, Microcystis aeruginosa, in the liver and muscle of traírão, Hoplias lacerdae.
• Grantee: Marcelo Gustavo Paulino
• Support Opportunities: Scholarships in Brazil - Doctorate