In the past few years, skeletal muscle has emerged as an important secretory organ producing soluble factors, called myokines, that exert either autocrine, paracrine or endocrine effects. Moreover, recent studies have shown that muscle releases microRNAs into the bloodstream in response to physical exercise. These microRNAs affect target cells, such as hormones and cytokines. The mechanisms underlying microRNA secretion are poorly characterized at present. Here, we investigated whether muscle tissue releases extracellular vesicles (EVs), which carry microRNAs in the bloodstream under physiological conditions such as physical exercise. Using density gradient separation of plasma from sedentary and physically fit young men we found EVs positive for TSG101 and alpha-sarcoglycan (SGCA), and enriched for miR-206. Cytometric analysis showed that the SGCA+ EVs account for 1–5% of the total and that 60–65% of these EVs were also positive for the exosomal marker CD81. Furthermore, the SGCA-immuno captured sub-population of EVs exhibited higher levels of the miR-206/miR16 ratio compared to total plasma EVs. Finally, a significant positive correlation was found between the aerobic fitness and muscle-specific miRNAs and EV miR-133b and -181a-5p were significantly up-regulated after acute exercise. Thus, our study proposes EVs as a novel means of muscle communication potentially involved in muscle remodeling and homeostasis.

Summary: Tuber magnatum , an ascomycetous fungus and obligate ectomycorrhizal symbiont, forms hypogeous fruit bodies, commonly called Italian white truffles. The diversity of bacterial communities associated with T. magnatum truffles was investigated using culture‐independent and ‐dependent 16S rRNA gene‐based approaches. Eighteen truffles were classified in three groups, representing different degrees of ascocarp maturation, based on the percentage of asci containing mature spores. The culturable bacterial fraction was (4.17 ± 1.61) × 10 ⁷ , (2.60 ± 1.22) × 10 ⁷ and (1.86 ± 1.32) × 10 ⁶ cfu g ⁻¹ for immature, intermediate and mature ascocarps respectively. The total of bacteria count was two orders of magnitude higher than the cfu g ⁻¹ count. Sequencing results from the clone library showed a significant presence of α ‐Proteobacteria (634 of the 771 total clones screened, c. 82%) affiliated with Sinorhizobium , Rhizobium and Bradyrhizobium spp. The bacterial culturable fraction was generally represented by γ‐ Proteobacteria (210 of the 384 total strains isolated, c. 55%), which were mostly fluorescent pseudomonads. Fluorescent in situ hybridization confirmed that α‐ Proteobacteria (85.8%) were the predominant components of truffle bacterial communities with β‐ Proteobacteria (1.5%), γ‐ Proteobacteria (1.9%), Bacteroidetes (2.1%), Firmicutes (2.4%) and Actinobacteria (3%) only poorly represented. Molecular approaches made it possible to identify α‐ Proteobacteria as major constituents of a bacterial component associated with T. magnatum ascoma, independently from the degree of maturation.

The occurrence, diversity, and pathogenicity of Vibrio spp. were investigated in two estuaries along the Italian Adriatic coast. Vibrio alginolyticus was the predominant species, followed by Vibrio parahaemolyticus , non-O1 Vibrio cholerae , and Vibrio vulnificus . By using a biochemical fingerprinting method, all isolates were grouped into nine phenotypes with similarity levels of 75 to 97.5%. The production of toxins capable of causing cytoskeleton-dependent changes was detected in a large number of Vibrio strains. These findings indicate a significant presence of potentially pathogenic Vibrio strains along the Adriatic coast.

The microbial community associated with ascocarps of the ectomycorrhizal fungus Tuber borchii Vittad. was studied by both cultivation and direct extraction of bacterial 16S rRNA gene (rDNA) sequence approaches. The inner part of six T. borchii ascoma collected in North-Central Italy was used to establish a bacterial culture collection and to extract the total genomic DNA to obtain a library of 16S rDNAs representative of the truffle bacterial community. Most of the isolates were affiliated to the gamma-Proteobacteria, mainly Fluorescent pseudomonads; some isolates were members of the Bacteroidetes group and Gram-positive bacteria, mostly Bacillaceae. The majority of the clones from the library were alpha-Proteobacteria showing significant similarity values, of greater than 97%, with members of the Sinorhizobium/Ensifer Group, Rhizobium and Bradyrhizobium spp. not previously identified as Tuber-associated bacteria. Only a few bacterial strains belonging to this bacterial subclass were found in the culture collection and isolated on a medium specific for Rhizobium-like organisms. A few clones were members of the beta- and gamma-Proteobacteria; as well as low and high G+C Gram-positive bacteria. Our findings clearly indicate that a dual approach increases the information obtained on the structural composition of a truffle bacterial community as compared to that derived via cultivation or direct recovery of 16S rDNA sequences alone.