Hemolymph microbiome of Pacific oysters in response to temperature, temperature stress and infection

Microbiota provide their hosts with a range of beneficial services, including defense from external pathogens. However, host-associated microbial communities themselves can act as a source of opportunistic pathogens depending on the environment. Marine poikilotherms and their microbiota are strongly influenced by temperature, but experimental studies exploring how temperature affects the interactions between both parties are rare. To assess the effects of temperature, temperature stress and infection on diversity, composition and dynamics of the hemolymph microbiota of Pacific oysters (Crassostrea gigas), we conducted an experiment in a fully-crossed, three-factorial design, in which the temperature acclimated oysters (8 or 22 °C) were exposed to temperature stress and to experimental challenge with a virulent Vibrio sp. Strain. We monitored oyster survival and repeatedly collected hemolymph of dead and alive animals to determine the microbiome composition by 16s rRNA gene amplicon pyrosequencing. We found that the microbial dynamics and composition of communities in healthy animals (including infection survivors) were significantly affected by temperature and temperature stress, but not by infection. The response was mediated by changes in the incidence and abundance of operational taxonomic units (OTUs) and accompanied by little change at higher taxonomic levels, indicating dynamic stability of the hemolymph microbiome. Dead and moribund oysters, on the contrary, displayed signs of community structure disruption, characterized by very low diversity and proliferation of few OTUs. We can therefore link short-term responses of host-associated microbial communities to abiotic and biotic factors and assess the potential feedback between microbiota dynamics and host survival during disease

Effects of free leucine supplementation and resistance training on muscle strength and functional status in older adults: a randomized controlled trial

Joan Trabal,1 Maria Forga,1 Pere Leyes,1 Ferran Torres,2,3 Jordi Rubio,4 Esther Prieto,5 Andreu Farran-Codina6 1Department of Endocrinology and Nutrition, Hospital Clínic Universitari de Barcelona, Barcelona, Catalonia, Spain; 2Biostatistics and Data Management Core Facility, IDIBAPS, Hospital Clinic Universitari de Barcelona, Barcelona, Catalonia, Spain; 3Biostatistics Unit, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain; 4Residencia Ballesol Almogavers, Grupo Ballesol, Barcelona, Catalonia, Spain; 5Centre de Rehabilitacio, Fundació Amiba, Badalona, Catalonia, Spain; 6Department of Nutrition and Food Science, Faculty of Pharmacy, Universitat de Barcelona, Barcelona, Catalonia, Spain Objective: To assess the effect of free leucine supplementation combined with resistance training versus resistance training only on muscle strength and functional status in older adults.Methods: This was a randomized, double-blind, placebo-controlled, parallel study with two intervention groups. Thirty older adults were randomly assigned to receive either 10 g leucine/day (leucine group [LG], n=15) or a placebo (control group [CG], n=15), plus resistance training over a 12-week period. Maximal overcoming isometric leg strength, functional status, nutritional status, body composition, health-related quality of life, depression, and dietary intake were assessed at 4 and 12 weeks. Missing data at 12 weeks were handled using mixed models for repeated measurements for data imputation.Results: Twenty-four subjects completed the 4-week assessment and eleven completed the 12-week intervention. Clinically significant gains were found in isometric leg strength at both assessment time points. Analysis of the effect size also showed how participants in LG outperformed those in CG for chair stands and the timed up and go test. No significant changes were observed for the rest of the outcomes.Conclusion: Our combined analysis showed moderate changes in isometric leg muscle strength and certain components of functional status. The magnitude of changes found on these outcomes should be qualified as a positive effect of the concomitant intervention. Keywords: aged, elderly, strength training, amino acid, functionalit