Metabolic Network for the Biosynthesis of Intra- and Extracellular alpha-Glucans Required for Virulence of Mycobacterium tuberculosis

Mycobacterium tuberculosis synthesizes intra- and extracellular alpha-glucans that were believed to originate from separate pathways. The extracellular glucose polymer is the main constituent of the mycobacterial capsule that is thought to be involved in immune evasion and virulence. However, the role of the alpha-glucan capsule in pathogenesis has remained enigmatic due to an incomplete understanding of alpha-glucan biosynthetic pathways preventing the generation of capsule-deficient mutants. Three separate and potentially redundant pathways had been implicated in alpha-glucan biosynthesis in mycobacteria: the GlgC-GlgA, the Rv3032 and the TreS-Pep2-GlgE pathways. We now show that alpha-glucan in mycobacteria is exclusively assembled intracellularly utilizing the building block alpha-maltose-1-phosphate as the substrate for the maltosyltransferase GlgE, with subsequent branching of the polymer by the branching enzyme GlgB. Some alpha-glucan is exported to form the alpha-glucan capsule. There is an unexpected convergence of the TreS-Pep2 and GlgC-GlgA pathways that both generate alpha-maltose-1-phosphate. While the TreS-Pep2 route from trehalose was already known, we have now established that GlgA forms this phosphosugar from ADP-glucose and glucose 1-phosphate 1000-fold more efficiently than its hitherto described glycogen synthase activity. The two routes are connected by the common precursor ADPglucose, allowing compensatory flux from one route to the other. Having elucidated this unexpected configuration of the metabolic pathways underlying alpha-glucan biosynthesis in mycobacteria, an M. tuberculosis double mutant devoid of alpha-glucan could be constructed, showing a direct link between the GlgE pathway, alpha-glucan biosynthesis and virulence in a mouse infection model

Stakeholder communication in 140 characters or less: a study of community sport foundations

Community sport foundations (CSFs), like other non-profit organizations, are increasingly employing social media such as Twitter to communicate their mission and activities to their diverse stakeholder groups. However, the way these CSFs utilize social media for communicating such practices remains unclear. Through a mixed-method approach of content analysis of tweets from 22 CSFs established by English professional football clubs and interviews with key individuals within these CSFs (n = 7), this study examines the extent to which CSFs’ core activities are being communicated through Twitter and identifies the strategies employed for doing so. Reflecting the target audiences CSFs are seeking to reach through Twitter and the challenges associated with communication about projects involving marginalized groups, tweets largely concern programs related to sports participation and education. The most frequently employed communication strategy is to inform, rather than interact or engage with stakeholders. However, CSFs with higher organizational capacity attempt to go beyond mere informing towards engaging with stakeholder groups that relate to their social agenda, highlighting the importance of trained and dedicated social media personnel in optimizing CSFs’ use of Twitter for communication

Personalized health, elearning, and mhealth interventions to improve nutritional status

Personalised health through nutrition has been made possible by recent advances in technology. We ran a search strategy in July 2016 to identify all existing studies on mobile/eLearning randomized controlled interventions designed to improve diet, nutrition and/or body weight in adults, at individual or community level. A total of 22 studies met the inclusion and exclusion criteria for inclusion. Most studies found that integrations of technology for delivering and personalizing interventions on diet/nutrition and/or body weight were effective in reducing body-weight in overweight/obese populations (n = 8), preventing weight gain n = 4) and improving certain dietary habits (n = 10). The low cost of eHealth/mHealth interventions and their potential to reach large, sometimes hard-to-reach young population sectors makes them attractive targets for upscaling

Post-processing Altimeter Data Towards Coastal Applications and Integration into Coastal Models

International audienceAltimetry missions in the last 16 years (TOPEX/Poseidon, ERS-1/2, GFO, Jason-1 and ENVISAT) and the recently-launched Jason-2 mission have resulted in great advances in deep ocean research and operational oceanography. However, oceanographic applications using satellite altimeter data have become very challenging over regions extending from near-shore to the continental shelf and slope (Cipollini et al. 2008). In these regions, intrinsic difficulties in the corrections (e.g., the high frequency ocean response to tidal and atmospheric loading, the mean sea level, etc.) and issues of land contamination in the radar altimeter and radiometer footprints result in systematic flagging and rejection of these data. Forthcoming altimeter missions (SARAL/AltiKa, SWOT, Sentinel-3, etc.) are designed to be better-suited for use in the coastal ocean. However, a number of studies have dealt with the problem of re-analysing, improving and exploiting the existing archive to monitor coastal dynamics. The early encouraging results (Vignudelli et al. 2005; Bouffard et al. 2008, Birol et al. submitted J Mar Syst 2009) support the need for continued research in coastal altimetry, with the opportunity of providing input and recommendations for future missions.This chapter reviews the current status of the X-TRACK processing application (Roblou et al. 2007), whose objectives are to improve both the quantity and quality of altimeter sea surface height (SSH) estimates in coastal regions by reprocessing a posteriori (the standard Geophysical Data Records) (GDR) as delivered by operational centres, i.e. by improving the post-processing stage. Latest improvements on along-track spatial resolution (high rate data streams and removal of large-scale errors) that promise improved monitoring of coastal dynamics are also detailed. In addition, with a view to integrating coastal-oriented altimeter datasets into models for coastal ocean state analysis, methodologies for matching models with observations are discussed