Mesodesma mactroides Gill Cells Exposed to Copper: Does Hyposmotic Saline Increase Cytotoxicity or Cellular Defenses?
Gill cells of filter feeding mollusks have cellular defense mechanisms, such as multixenobiotic resistance (MXR), that allow them to extrude possible contaminants. To analyze the cytotoxicity and cellular defenses of gills in the clam Mesodesma mactroides, gill cells were exposed to copper in both iso- and hyposmotic solutions. Analysis of MXR activity by fluorescence microscopy showed that hyposmotic saline activated defenses, whereas the presence of copper in isosmotic solution inhibited the activation of defenses. Cell viability was decreased in cells exposed to copper in isosmotic saline, but not in cells exposed to hyposmotic saline. We conclude that when cells cannot defend themselves due to decreased MXR, cell death occurs. In addition, gill cells under hyposmotic conditions have a greater capacity for defense and a lower rate of cellular mortality than when they are maintained under isosmotic conditions.
Programa de Pós-Graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Universidade Federal do Rio Grande, FURG, Rio Grande, RS, Brazil.
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Anjos
Curso de Graduação em Tecnologia em Toxicologia Ambiental, Universidade Federal do Rio Grande, FURG, Rio Grande, RS, Brazil.
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Galvão
Curso de Graduação em Tecnologia em Toxicologia Ambiental, Universidade Federal do Rio Grande, FURG, Rio Grande, RS, Brazil.
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Santos
Programa de Pós-Graduação em Ciências Fisiológicas, Fisiologia Animal Comparada, Universidade Federal do Rio Grande, FURG, Rio Grande, RS, Brazil. martasouza@furg.br.|Curso de Graduação em Tecnologia em Toxicologia Ambiental, Universidade Federal do Rio Grande, FURG, Rio Grande, RS, Brazil. martasouza@furg.br.|Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália km 8, Campus Carreiros, 96203-900, Rio Grande, RS, Brazil. martasouza@furg.br.
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Souza
D000818:Animals; D049872:Bivalvia / Q000166:cytology* / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D003300:Copper / Q000633:toxicity*; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D005880:Gills / Q000166:cytology* / Q000187:drug effects*; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D012965:Sodium Chloride / Q000494:pharmacology*; D014874:Water Pollutants, Chemical / Q000633:toxicity
D014874:Water Pollutants, Chemical; D012965:Sodium Chloride; D003300:Copper
Fluorescence microscopy; Fluorimetry; Hyposmotic challenge; MXR