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Liquid droplet formation by HP1α suggests a role for phase separation in heterochromatin.
Gene silencing by heterochromatin is proposed to occur in part as a result of the ability of heterochromatin protein 1 (HP1) proteins to spread across large regions of the genome, compact the underlying chromatin and recruit diverse ligands. Here we identify a new property of the human HP1α protein: the ability to form phase-separated droplets. While unmodified HP1α is soluble, either phosphorylation of its N-terminal extension or DNA binding promotes the formation of phase-separated droplets. Phosphorylation-driven phase separation can be promoted or reversed by specific HP1α ligands. Known components of heterochromatin such as nucleosomes and DNA preferentially partition into the HP1α droplets, but molecules such as the transcription factor TFIIB show no preference. Using a single-molecule DNA curtain assay, we find that both unmodified and phosphorylated HP1α induce rapid compaction of DNA strands into puncta, although with different characteristics. We show by direct protein delivery into mammalian cells that an HP1α mutant incapable of phase separation in vitro forms smaller and fewer nuclear puncta than phosphorylated HP1α. These findings suggest that heterochromatin-mediated gene silencing may occur in part through sequestration of compacted chromatin in phase-separated HP1 droplets, which are dissolved or formed by specific ligands on the basis of nuclear context
The organic geochemistry of ancient sediments, part II
Chemical analysis of sediment and oil hydrocarbon content by gas chromatography and mass spectrometry to establish inception period of bio-organic evolutio
Sustainable diets and biodiversity: Directions and solutions for policy, research and action
This book presents the current state of thought on the common path of sustainable diets and biodiversity. It consists of 4 chapters which look at sustainable diets and biodiversity through sustainable food production and consumption which is illustrated with ten cases studies. The final chapter deals more specifically with the example of the Mediterranean diet. The book resulted from an International Scientific Symposium “Biodiversity and Sustainable Diets: United Against Hunger” organized jointly by FAO and Bioversity International, held at FAO, in Rome, from 3 to 5 November 2010, within the World Food Day/Week programme, on the occasion of the 2010 International Year of Biodiversity. Book by chapters: Introduction Chapter 1 - SUSTAINABLE DIETS AND BIODIVERSITYChapter 2 - SUSTAINABLE FOOD PRODUCTION AND CONSUMPTIONChapter 3 - CASE STUDIES: BRINGING BIODIVERSITY TO THE PLATEChapter 4 - AN EXAMPLE OF A SUSTAINABLE DIET: THE MEDITERRANEAN DIE
What is a sustainable healthy diet? A discussion paper
The food system today is destroying the environment upon which future food production depends.
While the food system generates enough food energy for our population of over 7 billion it does not deliver adequate and affordable nutrition for all. About half the global population is inadequately or inappropriately nourished.
Without action, these problems are set to become acute. As our global population grows, urbanises and becomes wealthier, it is demanding more resource intensive, energy rich foods.
What, and how much we eat directly affects what, and how much is produced. We therefore need to consume more „sustainable diets‟ – diets that have lower environmental impacts, and are healthier.
But what does such a diet look like? Can health, environmental sustainability, and all the other goals we have for our food system really be reconciled, or will there be trade offs
Organic Geochemical Studies. I. Molecular Criteria for Hydrocarbon Genesis
In recent years the search for life-forms at the earliest periods of geological time has been continued not only at the morphological level but also at the molecular level. This has been possible as a result of the increase in the biochemical knowledge and with the advent of analytical techniques that are capable of describing the intimate molecular architecture of individual molecules in acute detail. The fundamental premises upon which this organic geochemical approach rest are the following: that certain molecules, possessing a characteristic structural skeleton, show a reasonable stability to degradation over long periods of geological time; that their structural specificity can be understood in terms of known biosynthetic sequences; and that their formation by any non-biological means is of negligible probability. In this manuscript it is proposed to critically re-examine these premises and to establish criteria whereby one can differentiate molecules derived from biological systems from those that have their origin in non-biological processes. The importance of establishing such criteria lies in the significance these criteria have in determining whether life exists, or has existed, on other planets. Within the very near future it may be possible to provide an initial answer to this question when the first lunar samples are returned to the earth for analysis
General scientific guidance for stakeholders on health claim applications
The European Food Safety Authority (EFSA) asked the Panel on Dietetic Products Nutrition and Allergies (NDA) to update the General guidance for stakeholders on the evaluation of Article 13.1, 13.5 and 14 health claims published in March 2011. Since then, the NDA Panel has completed the evaluation of Article 13.1 claims except for claims put on hold by the European Commission, and has evaluated additional health claim applications submitted pursuant to Articles 13.5, 14 and also 19. In addition, comments received from stakeholders indicate that general issues that are common to all health claims need to be further clarified and addressed. This guidance document aims to explain the general scientific principles applied by the NDA Panel for the evaluation of all health claims and outlines a series of steps for the compilation of applications. The general guidance document represents the views of the NDA Panel based on the experience gained to date with the evaluation of health claims, and it may be further updated, as appropriate, when additional issues are addressed
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