Marília de Dirceu Machado de Oliveira

The protective effect of ß-carotene on genotoxicity induced by cyclophosphamide

Abstract The influence of s-carotene on the clastogenicity of the indirect-acting mutagen cyclophosphamide (CPA) was investigated in mice, in vivo, for the induction of chromosome aberrations in bone marrow cells (BM). s-Carotene (0.5, 1.0, 2.0, 5.0, 10, 25, 50, 100 and 200 mg/kg) was administered by gavage for 5 consecutive days. 4 h after the last treatment with s-carotene, the mice were injected intraperitoneally with CPA, and the BM cells were fixed after 16, 24 and 32 h for the evaluation of the frequency of chromosome aberrations. The results showed that s-carotene was effective in reducing chromosomal damage induced by CPA with the increase of its concentration up to a level after which this effect was not observed. This anticlastogenicity was better detected when the cells were fixed at 32 h, although a tendency in reducing the CPA clastogenicity was already observed at 16 and 24 h. Our results suggest that s-carotene provides significant protection against the genotoxicity of CPA, although no dose-effect relationship on the frequencies of cells with chromosomal aberrations was observed.

Tolerance of Brazilian brain coral Mussismilia braziliensis to sediment and organic matter inputs

In Brazil, where reefs occur in markedly turbid environments, the relationship between sedimentation/organic matter and corals is poorly known. Thus, the ex situ effects of sediment with and without organic matter over the ΔF/Fm and physical state of Mussismilia braziliensis were analyzed. The ΔF/Fm and coral physical state, evaluated through the susceptibility index to sedimentation (SI), were measured in seven colonies exposed to sedimentation (0-450 mg cm(-2) day(-1)) free of organic matter after 45 days of exposure, and in 12 colonies exposed to sedimentation (0-500 mg cm(-2) day(-1)) with organic matter content (10%), in which case ΔF/Fm was measured after 72 h and SI after 120 h. In both cases there were effects of increasing sedimentation on the SI with no effect on ΔF/Fm. Despite the tolerance to high sedimentation rates shown by this coral, we noted that the presence of organic matter might reduce its tolerance to sedimentation stress.

The Coral Reef Province of Brazil

Abstract On the tropical coast of Brazil, coral reefs are prominent marine ecosystems, forming the largest and richest area of reefs in the southwestern Atlantic Ocean. These reefs are characterized by an unusual growth form of mushroom-shaped pinnacles, formed by a low diversity coral fauna rich in endemic species. The inshore reefs thrive in an environment influenced by a continentally derived intense siliciclastic sediment influx, whereas offshore reefs develop in the carbonate dominated middle and outer continental shelves. The inshore reefs are experiencing increasing degradation due to both natural processes (sea-level oscillations, ENSO events) and anthropogenic impacts, such as an accelerated coastal development, reef nutrification, marine pollution, tourism pressure, overexploitation of reef resources, and overfishing. A lowering of sea level that occurred after 5000 years BP, along the coast of Brazil, affected most coastal habitats, mobilizing the western continent-derived siliciclastic sediment toward the eastern reefs and associated habitats, exposing them to a heavy sedimentation. Coral bleaching events occur in the reefs of Brazil during El-Nino occurrences. Accelerated deforestation of coastal zones for urban development has been causing high influx of sediment to the reefs, mangrove forests, and seagrasses. Tourism pressure is already impacting the most visited areas including the yet still few number of marine protected areas (MPAs), and the number of divers per year is already high enough to be deleterious to the reefs. Extraction of coral fauna for the aquarium trade, overfishing and fishing with explosives in both the artisanal and commercial fisheries, and use of chemicals for indiscriminate catching of aquarium fishes are responsible for the mortality of some components of the reef biota. Effective protection of Brazilian reefs is still minimal, and for certain areas, was virtually nonexistent until the beginning of this century, when an initiative of the Directorate of Protected Areas of the Brazilian Government developed a project for the conservation of coral reefs, expanding its effort to map those found in existing Conservation Units, distributed along the entire coast of Brazil and including nearly all of the country’s oceanic islands.