Efeitos celulares em Mytella charruana expostos a sedimentos contaminados com HPAs em cenários futuros de acidificação e aquecimento do meio marinho
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Data
2021-02-23
Autores
Oliveira, Thaís Rafael de [UNIFESP]
Orientadores
Choueri, Rodrigo Brasil [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Ecossistemas marinhos experimentam alterações ambientais importantes no Antropoceno, como elevação da temperatura e acidificação das águas. Estas alterações despertam preocupação e movimentam esforços no sentido de compreender seus efeitos sobre a biota. Aliada a estas transformações ambientais, os ecossistemas marinhos sofrem ainda efeitos de outros estressores, incluindo a contaminação química. Os efeitos destes três estressores atuando sinergicamente sobre a vida marinha é ainda apenas hipotetizado. Portanto, o objetivo do presente estudo foi avaliar respostas de biomarcadores bioquímicos (danos em DNA e peroxidação lipídica) nas brânquias de Mytella charruana (Mollusca: Mytellidae) expostos a um cenário de aquecimento e acidificação previsto para o ano de 2100, devido ao aumento da concentração de CO2 no meio marinho, junto à contaminação química por HPAs no sedimento. Os organismos-teste foram expostos a sedimentos fortificados em laboratório com uma mistura de HPAs (Benzo[a]pireno e Acenafteno) e seus respectivos controles, em combinações de duas temperaturas (25°C e 27°C) e três níveis de pH (7.5, 7.1 e 6.7). Os tratamentos foram acidificados através da injeção controlada de CO2 gasoso puro no meio experimental. Após 96h de exposição, as brânquias dos indivíduos foram removidas para análise de danos em DNA através da quantificação da fragmentação do DNA (ensaio de precipitação alcalina), e peroxidação lipídica (LPO) através da quantificação de malondialdeído (método TBARs). Os dados foram analisados utilizando a PERMANOVA multifatorial para identificar possíveis interações entre contaminação, temperatura e pH. Efeitos interativos entre pH e contaminação só foram observados nos tratamentos com temperatura de 27°C. O pH foi o fator que exerceu maior influência na produção das respostas analisadas, apresentando efeitos nas duas temperaturas testadas. Houve um aumento significativo das respostas de danos em DNA e LPO no controle acetona em relação ao contaminado com HPAs nos níveis de pH 6.7 à temperatura de 27°C, cenário mais estressante testado, podendo ser uma resposta de supercompensação dos mecanismos de defesa dos organismos-teste. Com isso, pode-se concluir que o pH (sem interação com a contaminação), no pH mais baixo testado, afeta de forma discreta os organismos provocando danos em DNA e LPO, podendo ser intensificado pelo aumento da temperatura.
Marine ecosystems experience important environmental changes in the Anthropocene, such as rising temperatures and acidifying waters. These changes arouse concern and make efforts to understand its effects on biota. In addition to these environmental changes, marine ecosystems are also affected by other stressors, including chemical contamination. The effects of these three stressors acting synergistically on marine life are still only hypothesized. Therefore, the objective of the present study was to evaluate responses of biochemical biomarkers (DNA damage and lipid peroxidation) in the gills of Mytella charruana (Mollusca: Mytellidae) exposed to a warming and acidification scenario predicted for the year 2100, due to the increase in CO2 concentration in the marine environment, along with chemical contamination by PAHs in the sediment. The test organisms were exposed to laboratory-fortified sediments with a mixture of PAHs (Benzo [a] pyrene and Acenaftene) and their respective controls, in combinations of two temperatures (25 ° C and 27 ° C) and three pH levels ( 7.5, 7.1 and 6.7). The treatments were acidified by the controlled injection of pure CO2 gas in the experimental medium. After 96h of exposure, the gills of the individuals were removed for DNA damage analysis by quantifying DNA fragmentation (alkaline precipitation assay), and lipid peroxidation (LPO) by quantifying malondialdehyde (TBARs method). The data were analyzed using PERMANOVA multifactorial to identify possible interactions between contamination, temperature and pH. Interactive effects between pH and contamination were only observed in treatments with a temperature of 27 ° C. PH was the factor that exerted the greatest influence on the production of the analyzed responses, with effects on the two temperatures tested. There was a significant increase in DNA and LPO damage responses in acetone control compared to those contaminated with PAHs at pH 6.7 levels at 27 ° C, the most stressful scenario tested, which may be an overcompensation response of the organisms' defense mechanisms -test. With this, it can be concluded that the pH (without interaction with the contamination), in the lowest tested pH, slightly affects the organisms causing damage to DNA and LPO, which can be intensified by the temperature increase.
Marine ecosystems experience important environmental changes in the Anthropocene, such as rising temperatures and acidifying waters. These changes arouse concern and make efforts to understand its effects on biota. In addition to these environmental changes, marine ecosystems are also affected by other stressors, including chemical contamination. The effects of these three stressors acting synergistically on marine life are still only hypothesized. Therefore, the objective of the present study was to evaluate responses of biochemical biomarkers (DNA damage and lipid peroxidation) in the gills of Mytella charruana (Mollusca: Mytellidae) exposed to a warming and acidification scenario predicted for the year 2100, due to the increase in CO2 concentration in the marine environment, along with chemical contamination by PAHs in the sediment. The test organisms were exposed to laboratory-fortified sediments with a mixture of PAHs (Benzo [a] pyrene and Acenaftene) and their respective controls, in combinations of two temperatures (25 ° C and 27 ° C) and three pH levels ( 7.5, 7.1 and 6.7). The treatments were acidified by the controlled injection of pure CO2 gas in the experimental medium. After 96h of exposure, the gills of the individuals were removed for DNA damage analysis by quantifying DNA fragmentation (alkaline precipitation assay), and lipid peroxidation (LPO) by quantifying malondialdehyde (TBARs method). The data were analyzed using PERMANOVA multifactorial to identify possible interactions between contamination, temperature and pH. Interactive effects between pH and contamination were only observed in treatments with a temperature of 27 ° C. PH was the factor that exerted the greatest influence on the production of the analyzed responses, with effects on the two temperatures tested. There was a significant increase in DNA and LPO damage responses in acetone control compared to those contaminated with PAHs at pH 6.7 levels at 27 ° C, the most stressful scenario tested, which may be an overcompensation response of the organisms' defense mechanisms -test. With this, it can be concluded that the pH (without interaction with the contamination), in the lowest tested pH, slightly affects the organisms causing damage to DNA and LPO, which can be intensified by the temperature increase.
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OLIVEIRA, Thaís Rafael de. Efeitos celulares em Mytella charruana expostos a sedimentos contaminados com HPAs em cenários futuros de acidificação e aquecimento do meio marinho. 2021. 37f. Trabalho de conclusão de curso de graduação (Bacharelado Interdisciplinar em Ciência e Tecnologia do Mar) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2021.