Exploring Metabolic Pathway Reconstruction and Genome-Wide Expression Profiling in Lactobacillus reuteri to Define Functional Probiotic Features

The genomes of four Lactobacillus reuteri strains isolated from human breast milk and the gastrointestinal tract have been recently sequenced as part of the Human Microbiome Project. Preliminary genome comparisons suggested that these strains belong to two different clades, previously shown to differ with respect to antimicrobial production, biofilm formation, and immunomodulation. To explain possible mechanisms of survival in the host and probiosis, we completed a detailed genomic comparison of two breast milk–derived isolates representative of each group: an established probiotic strain (L. reuteri ATCC 55730) and a strain with promising probiotic features (L. reuteri ATCC PTA 6475). Transcriptomes of L. reuteri strains in different growth phases were monitored using strain-specific microarrays, and compared using a pan-metabolic model representing all known metabolic reactions present in these strains. Both strains contained candidate genes involved in the survival and persistence in the gut such as mucus-binding proteins and enzymes scavenging reactive oxygen species. A large operon predicted to encode the synthesis of an exopolysaccharide was identified in strain 55730. Both strains were predicted to produce health-promoting factors, including antimicrobial agents and vitamins (folate, vitamin B12). Additionally, a complete pathway for thiamine biosynthesis was predicted in strain 55730 for the first time in this species. Candidate genes responsible for immunomodulatory properties of each strain were identified by transcriptomic comparisons. The production of bioactive metabolites by human-derived probiotics may be predicted using metabolic modeling and transcriptomics. Such strategies may facilitate selection and optimization of probiotics for health promotion, disease prevention and amelioration

ANALISI DELLE CONSEGUENZE DEL RILASCIO ACCIDENTA-LE DI METANO DA UN GASDOTTO

Transmission pipelines carrying natural gas are not typically within secure industrial sites and may cross through both rural and heavily populated areas. Failure of the pipeline can lead to various outcomes, some of which can pose a significant threat of damage to people and properties in the immediate vicinity of the failure location. Statistical data of accidents in Europe showed that the rupture of a pipeline can be caused by mechanical fracture, ex-ternal mechanical interference by third party and earthquake. Statistical data also showed an overall failure rate of 0.575 per 1000 km.year. In the event of rupture, a gas cloud would form and its size depends on the geometrical parameters of the pipeline and of the rupture. Estimation of the gas cloud size will be needed therefore to analyse this kind of accindents. This study is focused to propose a simple and reliable approach to sizing the ground area potentially affected by the failure of a high-pressure pipeline carrying natural gas

Total and abdominal obesity are risk factors for gastroesophageal reflux symptoms in children.

OBJECTIVES: The association between GERD and obesity has been frequently reported in adults. Data in children are scarce and inconclusive, evaluating only general obesity. Central adiposity has never been investigated in children as a possible risk factor for GERD. The aims of the present study were to evaluate the prevalence of gastroesophageal reflux disease (GERD) symptoms in overweight and obese children in comparison with a general normal-weight population and whether the GERD symptoms are associated with waist circumference (WC). METHODS: The study population consisted of 153 healthy children. A detailed clinical history and a physical examination were obtained from each patient. A questionnaire on reflux symptoms was completed by caregivers. RESULTS: The reflux symptomatic score resulted significantly higher in obese than in normal-weight children and in children with WC >90th percentile compared with those with WC <75th percentile. CONCLUSIONS: These preliminary data show that both total and abdominal obesity are risk factors for the development of GERD symptoms in children. The risk of GERD symptoms rises progressively with the increase in both body mass index and waist circumference, even in normal-weight children