Publicação
Impact of seawater acidification in starfish regeneration: a proteomic approach
| Resumo: | Since the start of the industrial revolution (XVIII century), atmospheric levels of carbon dioxide (CO2) have been rising at a far greater rate than previously experienced, increasing CO2 dissolved in seawater. This process is recognized as ocean acidification and can severely damage calcifying organisms. Since echinoderms have an endoskeleton composed of magnesium calcite, they are predicted to be a sensitive taxa affected by this acidic environment. Taking into account that some species of this filo have a faster regeneration capacity under low pH, analysis of the proteome represents a powerful tool to examine these physiological trait at a molecular level. Trying to strengthen this work on ocean acidification effects, we studied Asterias rubens’ behaviour by observing their preference in choosing a leading arm when submitted to different regeneration time-points (non-regeneration and regeneration after 1, 4, 9 and 14 days) and at two pH environments (control (CpH) – 8.1 and low (LpH) – 7.7). It was concluded that they do not have a preference leading arm before ablation in both pH environments. Although, one day after ablation they drastically decrease the use of the wounded arms, as expected, while the non-amputated arms did not suffer any changes. Furthermore, after nine days subjected to these conditions, it seems that sea stars recovered completely the movement of the amputated arms. Asterosaponins search was also a vital part of this work, since they are known for having important functions in sea stars. We observed that two of the nine asterosaponins detected in the control pH were also detected in low pH samples, and that their concentration decreased, suggesting that acidic pH may alter their biosynthesis. Proteins from both cell-free coelomic fluid (CFF) and radial nerve cord (RNC) were extracted, digested and further analyzed by nano LC-MS/MS. We were able to identify 298 proteins, being 81% of all proteins identified differentially expressed. A surprising finding was the almost absence of stress proteins in an acidic pH environment. In this work, we propose a correlation between an acidic environment and asterosaponins’ biological effects. The decline in diversity and amount of these biomolecules can be caused by already known decreases in respiratory rate and cholesterol absorption. Although, asterosaponins might have positive effects in predation and reproduction. The detected increase in vitellogenin expression seems to be associated with the amplified spawning event induced by the low levels of asterosaponins at acidic pH, thereby also enhancing reproduction. |
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| Autores principais: | Marques, Vera Cristina J. |
| Assunto: | Acidificação A. Rubens Comportamento Asterosaponinas Proteoma Teses de mestrado - 2015 |
| Ano: | 2015 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Since the start of the industrial revolution (XVIII century), atmospheric levels of carbon dioxide (CO2) have been rising at a far greater rate than previously experienced, increasing CO2 dissolved in seawater. This process is recognized as ocean acidification and can severely damage calcifying organisms. Since echinoderms have an endoskeleton composed of magnesium calcite, they are predicted to be a sensitive taxa affected by this acidic environment. Taking into account that some species of this filo have a faster regeneration capacity under low pH, analysis of the proteome represents a powerful tool to examine these physiological trait at a molecular level. Trying to strengthen this work on ocean acidification effects, we studied Asterias rubens’ behaviour by observing their preference in choosing a leading arm when submitted to different regeneration time-points (non-regeneration and regeneration after 1, 4, 9 and 14 days) and at two pH environments (control (CpH) – 8.1 and low (LpH) – 7.7). It was concluded that they do not have a preference leading arm before ablation in both pH environments. Although, one day after ablation they drastically decrease the use of the wounded arms, as expected, while the non-amputated arms did not suffer any changes. Furthermore, after nine days subjected to these conditions, it seems that sea stars recovered completely the movement of the amputated arms. Asterosaponins search was also a vital part of this work, since they are known for having important functions in sea stars. We observed that two of the nine asterosaponins detected in the control pH were also detected in low pH samples, and that their concentration decreased, suggesting that acidic pH may alter their biosynthesis. Proteins from both cell-free coelomic fluid (CFF) and radial nerve cord (RNC) were extracted, digested and further analyzed by nano LC-MS/MS. We were able to identify 298 proteins, being 81% of all proteins identified differentially expressed. A surprising finding was the almost absence of stress proteins in an acidic pH environment. In this work, we propose a correlation between an acidic environment and asterosaponins’ biological effects. The decline in diversity and amount of these biomolecules can be caused by already known decreases in respiratory rate and cholesterol absorption. Although, asterosaponins might have positive effects in predation and reproduction. The detected increase in vitellogenin expression seems to be associated with the amplified spawning event induced by the low levels of asterosaponins at acidic pH, thereby also enhancing reproduction. |
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