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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Osmoregulatory disturbance in Neotropical fish exposed to the crude extracts of the cyanobacterium, Radiocystis fernandoi

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Author(s):
Tavares, Driele [1] ; Paulino, Marcelo Gustavo [1, 2] ; Terezan, Ana Paula [3] ; Fernandes, Joao Batista [3] ; Giani, Alessandra [4] ; Fernandes, Marisa Narciso [1]
Total Authors: 6
Affiliation:
[1] Univ Fed Sao Carlos, Dept Physiol Sci, Rodovia Washington Luiz Km 235, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Fed Tocantins, Setor Cimba, Campus Araguaina, Ave Paraguai S-N, BR-77824838 Araguaina, TO - Brazil
[3] Univ Fed Sao Carlos, Dept Chem, Rodovia Washington Luiz Km 235, BR-13565905 Sao Carlos, SP - Brazil
[4] Univ Fed Minas Gerais, Dept Bot, Ave Pres Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG - Brazil
Total Affiliations: 4
Document type: Journal article
Source: AQUATIC TOXICOLOGY; v. 216, NOV 2019.
Web of Science Citations: 0
Abstract

Blooms of cyanobacteria, a common event in eutrophic environments, result in the release of potentially toxic substances into the water. The cyanobacterium Radiocystis fernandoi produces microcystin (MC) and other peptides that may disturb homeostasis. This study evaluated the effect of intraperitoneal injections containing the crude extract (CE) of R. fernandoi strain R28 on the gills and kidneys of neotropical fish, Piaractus mesopotamicus, 3, 6 and 24 h post-injection. CE contained MC-RR, MC-YR and minor other oligopeptides. Plasma ions and the activities of the enzymes PP1 and PP2A, Na+/K+-ATPase (NKA), H+-ATPase (HA) and carbonic anhydrase (CA) were determined and morphological changes in both the gills and kidneys were characterized. Compared to controls, the concentration of Na+ within the plasma of P. mesopotamicus decreased after treatment with CE 3 h post treatment and increased after 24 h; the concentration of K+ decreased after 6 h. The activity of the endogenous PP1 and PP2A was unchanged in the gills and was inhibited in the kidneys 6 h after i.p. injection. In the gills, NKA activity increased after 3 h and decreased 6 h post i.p. exposure. Further, NKA activity did not differ from the controls 24-h post injection. In the kidneys, NKA, HA and CA activities were unaffected by treatment. The mitochondria-rich cell (MRC) density in the gills decreased after 3 h in the filament and 3 and 6 h in the lamellae and was restored to the control levels 24 h post-exposure. Filament epithelial hyperplasia and hypertrophy, lamellar atrophy and rupture of the lamellar epithelium were the most common effects of treatment in the gills. No histopathological changes occurred in the kidneys. This study demonstrates that a single dose of toxic CE from R. fernandoi can cause a transitory ion imbalance in P. mesopotamicus which is related to the changes in MRC levels and NKA activity. Ionic balance was recovered 24 h post i.p. injection, however, morphological changes that occurred in the gills took a longer amount of time to return to normal. To conclude, the effects of components contained within the CE of R. fernandoi may be harmful to P. mesopotamicus. In particular, the recovery of ionic regulation depends on MRC responses and histopathological changes produced by CE may affect gas exchange and other gill functions. (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