Carbohydrate Metabolism Is Essential for the Colonization of Streptococcus thermophilus in the Digestive Tract of Gnotobiotic Rats

Streptococcus thermophilus is the archetype of lactose-adapted bacterium and so far, its sugar metabolism has been mainly investigated in vitro. The objective of this work was to study the impact of lactose and lactose permease on S. thermophilus physiology in the gastrointestinal tract (GIT) of gnotobiotic rats. We used rats mono-associated with LMD-9 strain and receiving 4.5% lactose. This model allowed the analysis of colonization curves of LMD-9, its metabolic profile, its production of lactate and its interaction with the colon epithelium. Lactose induced a rapid and high level of S. thermophilus in the GIT, where its activity led to 49 mM of intra-luminal L-lactate that was related to the induction of mono-carboxylic transporter mRNAs (SLC16A1 and SLC5A8) and p27Kip1 cell cycle arrest protein in epithelial cells. In the presence of a continuous lactose supply, S. thermophilus recruited proteins involved in glycolysis and induced the metabolism of alternative sugars as sucrose, galactose, and glycogen. Moreover, inactivation of the lactose transporter, LacS, delayed S. thermophilus colonization. Our results show i/that lactose constitutes a limiting factor for colonization of S. thermophilus, ii/that activation of enzymes involved in carbohydrate metabolism constitutes the metabolic signature of S. thermophilus in the GIT, iii/that the production of lactate settles the dialogue with colon epithelium. We propose a metabolic model of management of carbohydrate resources by S. thermophilus in the GIT. Our results are in accord with the rationale that nutritional allegation via consumption of yogurt alleviates the symptoms of lactose intolerance

Recommendations for National Risk Assessment for Disaster Risk Management in EU

Decision No 1313/2013/EU on a Union Civil Protection Mechanism (UCPM) calls Participating States to develop risk assessments periodically and make the summary of their National Risk Assessment (NRA) available to the European Commission as a way to prevent disaster risk in Europe. In order to facilitate countries on this task, the European Commission developed the Guidelines on risk assessment and mapping. In spite of these, the summaries received have revealed several challenges related to the process and the content of the assessments. The current report aims to provide scientific support to the UCPM participant countries in their development of NRA, explaining why and how a risk assessment could be carried out, how the results of this could be used for Disaster Risk Management planning and in general, how science can help civil protection authorities and staff from ministries and agencies engaged in NRA activities. The report is the result of the collaborative effort of the Disaster Risk Management Knowledge Centre team and nine Joint Research Centre expert groups which provided their insight on tools and methods for specific risk assessment related to certain hazards and assets: drought, earthquakes, floods, terrorist attacks, biological disasters, critical infrastructures, chemical accidents, nuclear accidents and Natech accidents. The current document would be improved by a next version that would include scientific guidance on other risks and the collaboration of potential users.JRC.E.1-Disaster Risk Managemen