Browsing by Author "Martins, Marta"
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- Ervilia castanea (Mollusca, Bivalvia) populations adversely affected at CO2 seeps in the North AtlanticPublication . Martins, Marta; Carreiro-Silva, Marina; Martins, Gustavo M.; Barcelos e Ramos, Joana; Viveiros, Fátima; Couto, Ruben P.; Parra, Hugo; Monteiro, João; Gallo, Francesca; Silva, Catarina; Teodosio, MA; Guilini, Katja; Hall-Spencer, Jason M.; Leitão, Francisco; Chicharo, Luis; Range, PedroSites with naturally high CO2 conditions provide unique opportunities to forecast the vulnerability of coastal ecosystems to ocean acidification, by studying the biological responses and potential adaptations to this increased environmental variability. In this study, we investigated the bivalve Ervilia castanea in coastal sandy sediments at reference sites and at volcanic CO2 seeps off the Azores, where the pH of bottom waters ranged from average oceanic levels of 8.2, along gradients, down to 6.81, in carbonated seawater at the seeps. The bivalve population structure changed markedly at the seeps. Large individuals became less abundant as seawater CO2 levels rose and were completely absent from the most acidified sites. In contrast, small bivalves were most abundant at the CO2 seeps. We propose that larvae can settle and initially live in high abundances under elevated CO2 levels, but that high rates of post-settlement dispersal and/or mortality occur. Ervilia castanea were susceptible to elevated CO2 levels and these effects were consistently associated to lower food supplies. This raises concerns about the effects of ocean acidification on the brood stock of this species and other bivalve molluscs of similar life history traits.
- Exploring the cytotoxic activity of new phenanthroline salicylaldimine Zn(II) complexesPublication . Matos, Cristina P.; Addis, Yemataw; Nunes, Patrique; Barroso, Sonia; Alho, Irina; Martins, Marta; Matos, Antonio P. A.; Marques, Fernanda; Cavaco, Isabel; Pessoa, Joao Costa; Correia, IsabelZinc(II) complexes bearing N-salicylideneglycinate (Sal-Gly) and 1,10-phenanthroline (phen) or phenanthroline derivatives [NN= 5-chloro-1,10-phenanthroline, 5-amine-1,10-phenanthroline (amphen), 4,7-diphenyl-1,10-phenanthroline (Bphen) and 5,6-epoxy-5,6-dihydro-1,10-phenanthroline] are synthesized. Complexes formulated as [Zn(NN)(2)(H2O)(2)](2+) (NN = phen and amphen), are also prepared. The cytotoxicity of the compounds is evaluated towards a panel of human cancer cells: ovarian (A2780), breast (MCF7) and cervical (HeLa), as well as non-tumoral V79 fibroblasts. All compounds display higher cytotoxicity than cisplatin (IC50 = 22.5 +/- 5.0 mu M) towards ovarian cells, showing IC50 values in the low micromolar range. Overall, all compounds show higher selectivity for the A2780 cells than for the non tumoral cells and higher selectivity indexes (IC50(V79)/IC50(A2780) than cisplatin. [Zn(Sal-Gly)(NNI(H2O)] complexes induce caspase-dependent apoptosis in A2780 cells, except [Zn(Sal-Gly)(Bphen)(H2O)], one of the most cytotoxic of the series. The cellular uptake in the ovarian cells analyzed by Inductively Coupled Plasma mass spectrometry indicates different Zn distribution profiles. Transmission electronic microscopy shows mitochondria alterations and apoptotic features consistent with caspase activationells incubated with EZn(Sal-Gly)(amphen)(H2O)] present additional nuclear membrane alterations in agreement with significant association with the nucleus. The increase of reactive oxygen species and lipid peroxidation forms could be related to apoptosis induction. [Zn(NN)(2)(H2O)(2)](2+) complexes have high ability to bind DNA through intercalation/groove binding, and circular dichroism data suggests that the main type of species that interact with DNA is [Zn(NN)](2+). Studies varying the % of fetal bovine serum (1-15%) in cell media show that albumin binding decreases the complex activity, indicating that distinct speciation of Zn- and phen-containing species in cell media may affect the cytotoxicity.