Beschreibung: Marine phytoplankton have developed the remarkable ability to tightly regulate the concentration of free calcium ions in the intracellular cytosol at a level of ~ 0.1 μmol L−1 in the presence of seawater Ca2+ concentrations of 10 mmol L−1. The low cytosolic calcium ion concentration is of utmost importance for proper cell signalling function. While the regulatory mechanisms responsible for the tight control of intracellular Ca2+ concentration are not completely understood, phytoplankton taxonomic groups appear to have evolved different strategies, which may affect their ability to cope with changes in seawater Ca2+ concentrations in their environment on geological timescales. For example, the Cretaceous (145 to 66 Ma), an era known for the high abundance of coccolithophores and the production of enormous calcium carbonate deposits, exhibited seawater calcium concentrations up to 4 times present-day levels. We show that calcifying coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica and Coccolithus braarudii) are able to maintain their relative fitness (in terms of growth rate and photosynthesis) at simulated Cretaceous seawater calcium concentrations, whereas these rates are severely reduced under these conditions in some non-calcareous phytoplankton species (Chaetoceros sp., Ceratoneis closterium and Heterosigma akashiwo). Most notably, this also applies to a non-calcifying strain of E. huxleyi which displays a calcium sensitivity similar to the non-calcareous species. We hypothesize that the process of calcification in coccolithophores provides an efficient mechanism to alleviate cellular calcium poisoning and thereby offered a potential key evolutionary advantage, responsible for the proliferation of coccolithophores during times of high seawater calcium concentrations. The exact function of calcification and the reason behind the highly ornate physical structures of coccoliths remain elusive.

Beschreibung: Mesenchymal stem cells are enriched in head neck squamous cell carcinoma, correlates with tumour size and inhibit T-cell proliferation British Journal of Cancer 112, 745 (17 February 2015). doi:10.1038/bjc.2015.15 Authors: F Liotta, V Querci, G Mannelli, V Santarlasci, L Maggi, M Capone, M C Rossi, A Mazzoni, L Cosmi, S Romagnani, E Maggi, O Gallo & F Annunziato

Beschreibung: Background: This article is part of a series commissioned by the International Epidemiological Association, aimed at describing population health and epidemiological resources in the six World Health Organization (WHO) regions. It covers 32 of the 53 WHO European countries, namely the Western European countries, the Balkan countries and the Baltic countries. Methods: The burdens of mortality and morbidity and the patterns of risk factors and inequalities have been reviewed in order to identify health priorities and challenges. Literature and internet searches were conducted to stock-take epidemiological teaching, research activities, funding and scientific productivity. Findings: These countries have among the highest life expectancies worldwide. However, within- and between-country inequalities persist, which are largely due to inequalities in distribution of main health determinants. There is a long tradition of epidemiological research and teaching in most countries, in particular in the Western European countries. Cross-national networks and collaborations are increasing through the support of the European Union which fosters procedures to standardize educational systems across Europe and provides funding for epidemiological research through framework programmes. The number of Medline-indexed epidemiological research publications per year led by Western European countries has been increasing. The countries accounts for nearly a third of the global epidemiological publication. Conclusions: Although population health has improved considerably overall, persistent within- and between-country inequalities continue to challenge national and European health institutions. More research, policy and action on the social determinants of health are required in the region. Epidemiological training, research and workforce in the Baltic and Balkan countries should be strengthened. European epidemiologists can play pivotal roles and must influence legislation concerning production and access to high-quality data.