Surface and deep water variations during MIS 11-15 at IODP Site U1313 in the Mid-Latitude North Atlantic : insights into Mid-Pleistocene rapid climate change

AGU Fall Meeting, S. Francisco (USA), 19-14 December 200

Efeitos de disrupção endócrina dos substitutos do Bisfenol A (Bisfenol F e Bisfenol S) na artéria umbilical humana

O bisfenol F (BPF) e o bisfenol S (BPF) são dois compostos químicos que nos últimos anos têm vindo a ser utilizados em diversos produtos do quotidiano para substituir o bisfenol A (BPA), pois a exposição a este foi associada ao desenvolvimento de diversas patologias, nomeadamente as cardiovasculares. Contudo, estudos recentes também têm vindo a relacionar também a exposição aos substitutos do BPA com o desenvolvimento de várias doenças, como neurológicas, tiroideias, comportamentais e cardiovasculares. Deste modo, têm vindo a ser levantadas questões quanto à segurança dos substitutos do BPA para a saúde humana. Preocupantemente, alguns estudos referem que os substitutos podem exercer efeitos disruptivos tão ou mais graves que o BPA. No entanto, os estudos existentes ainda são pouco vastos e conclusivos, nomeadamente, ao nível dos efeitos cardiovasculares. Deste modo, o objetivo principal deste trabalho foi estudar os efeitos do BPA, BPF e BPS no tónus arterial e analisar quais os possíveis mecanismos envolvidos nesses efeitos. Além disso, pretendeu-se perceber se os efeitos provocados pelos substitutos do BPA (BPF e BPS) são mais ou menos adversos do que os causados pelo BPA. Os resultados deste trabalho parecem demonstrar que o BPA, BPS e BPF exercem efeitos relaxantes rápidos (não genómicos) e independentes de endotélio nas artérias umbilicais humanas (HUAs). Estes efeitos também foram observados para o BPF e BPS a nível celular, isto é, em células musculares lisas das artérias umbilicais humanas (HUASMCs). A nível dos efeitos a longo prazo, os resultados parecem demonstrar que o mecanismo contrátil das HUAs incubadas durante 24 horas com BPA estava alterado, ao contrário do que se verificava nas HUAs incubadas com BPF. Porém, ainda a nível genómico, constatou-se que tanto o BPA como o BPF podem interferir com os principais mecanismos responsáveis pela relaxação das HUAs, interferindo com a via NO/sGC/cGMP/PKG e modulando a atividade dos canais de Ca2+ do tipo L (LTCC), sendo que os resultados parecem demonstrar que o BPF altera mais a resposta vasorelaxante do que o BPA. Deste modo, a substituição do BPA pelos seus análogos não parece ser benéfica para a saúde humana cardiovascular. Assim, futuramente, os efeitos vasculares destes bisfenóis devem continuar a ser avaliados de modo clarificar os seus modos de ação e implicações futuras na saúde materno-fetal.In recent years, the chemical compounds bisphenol F (BPF) and bisphenol S (BPS) have been used in several everyday products to replace bisphenol A (BPA), since exposure to BPA has been associated with the development of several pathologies, including cardiovascular diseases. However, recent studies have also been associating exposure to BPA substitutes with the development of various pathologies, such as neurological, thyroid, behavioral, and cardiovascular diseases. Therefore, questions have been raised about the safety of BPA substitutes for human health. Worryingly, some studies reported that BPA substitutes may cause disruptive effects as harmful, or even more severe, than BPA. However, the existing literature is still limited and inconclusive, particularly concerning cardiovascular effects. In this sense, the aim of the present work was to study the effects of BPA, BPF, and BPS on arterial tone and to analyze the possible mechanisms involved in these effects. Furthermore, it was aimed to understand whether the effects caused by BPA substitutes (BPF and BPS) are more, or less, adverse than those caused by BPA. Our results seem to demonstrate that BPA, BPS, and BPF exert rapid (non-genomic) and endothelium-independent relaxant effects in human umbilical arteries (HUAs). These effects were also observed for BPF and BPS at the cellular level, i.e., in human umbilical artery smooth muscle cells (HUASMCs). Regarding the long-term effects, the results seem to demonstrate that in HUAs incubated for 24 hours with BPA, the contractile mechanism was altered, in contrast to HUAs incubated with BPF. However, also at the genomic level, it was found that both BPA and BPF can disturb the main mechanisms responsible for the relaxation of HUAs, by interfering with the NO/sGC/cGMP/PKG pathway and modulating the activity of L-type Ca2+ channels (LTCC). Moreover, our results seem to demonstrate that BPF alters more the vasorelaxant response than BPA. Therefore, replacing BPA with its analogs does not seem to be beneficial for human cardiovascular health. Thus, in the future, the vascular effects of these bisphenols should continue to be evaluated to clarify their modes of action and future implications for maternal-fetal health

Phytoplankton biogeography and community stability in the ocean

BACKGROUND: Despite enormous environmental variability linked to glacial/interglacial climates of the Pleistocene, we have recently shown that marine diatom communities evolved slowly through gradual changes over the past 1.5 million years. Identifying the causes of this ecological stability is key for understanding the mechanisms that control the tempo and mode of community evolution. METHODOLOGY/PRINCIPAL FINDINGS: If community assembly were controlled by local environmental selection rather than dispersal, environmental perturbations would change community composition, yet, this could revert once environmental conditions returned to previous-like states. We analyzed phytoplankton community composition across >10(4) km latitudinal transects in the Atlantic Ocean and show that local environmental selection of broadly dispersed species primarily controls community structure. Consistent with these results, three independent fossil records of marine diatoms over the past 250,000 years show cycles of community departure and recovery tightly synchronized with the temporal variations in Earth's climate. CONCLUSIONS/SIGNIFICANCE: Changes in habitat conditions dramatically alter community structure, yet, we conclude that the high dispersal of marine planktonic microbes erases the legacy of past environmental conditions, thereby decreasing the tempo of community evolution

Impact of Manganese, Copper and Zinc Ions on the Transcriptome of the Nosocomial Pathogen Enterococcus faecalis V583

Mechanisms that enable Enterococcus to cope with different environmental stresses and their contribution to the switch from commensalism to pathogenicity of this organism are still poorly understood. Maintenance of intracellular homeostasis of metal ions is crucial for survival of these bacteria. In particular Zn2+, Mn2+ and Cu2+ are very important metal ions as they are co-factors of many enzymes, are involved in oxidative stress defense and have a role in the immune system of the host. Their concentrations inside the human body vary hugely, which makes it imperative for Enterococcus to fine-tune metal ion homeostasis in order to survive inside the host and colonize it. Little is known about metal regulation in Enterococcus faecalis. Here we present the first genome-wide description of gene expression of E. faecalis V583 growing in the presence of high concentrations of zinc, manganese or copper ions. The DNA microarray experiments revealed that mostly transporters are involved in the responses of E. faecalis to prolonged exposure to high metal concentrations although genes involved in cellular processes, in energy and amino acid metabolisms and genes related to the cell envelope also seem to play important roles