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This study examined the association between genetic variations in the Vitamin D Receptor (VDR) gene and the composition of gut microbiota in a Spanish population. The VDR gene plays a role in mediating the effects of vitamin D on gut microbiota composition. We analyzed 87 healthy participants from the Spanish Caucasian population and found that the genetic variations were in Hardy–Weinberg equilibrium. Through metataxonomic sequencing, we identified that the GG genotype from the VDR polymorphism rs731236 seems to be associated with the opportunistic genus Solobacterium, indicating that genetic variations may influence the composition of gut microbiota. [ABSTRACT FROM AUTHOR]

Introduction: Adolescence is a vulnerable period for the onset of eating disorders (ED) such as anorexia and bulimia nervosas. Body dissatisfaction, a precipitating factor for ED, leads adolescents to seek information on the Internet about diets. In this context, pro-Ana (proanorexia) and pro-Mia (probulimia) are on-line pages that promulgate highly harmful contents for health related to weight loss and ED. Objectives: The aim of this study was to analyze quantity, quality and social diffusion strategies used by pro-Ana and pro-Mia webpages. Methods: A web search was done in the Google Chrome browser, using the keywords “anorexia”, “bulimia”, “eating disorders”, “Ana and Mia”, “pro-Ana and pro-Mia”, “anorexic nation”, “obesity”, “healthy lifestyles” and “healthy nutrition”. The top 20 results for each search were selected and analyzed according to positioning rates (PageRank, PR). The quality of these resources was analyzed by a previously published questionnaire. Finally, a study of the diffusion in social networks like Facebook and Twitter was performed for pro-Ana and pro-Mia pages using SharedCount. Results: Searches for pro-Ana and pro-Mia reported more than a million entries. The pages were poorly positioned. Blog contents were the most shared between all the analyzed pages. Conclusions: pro-Ana and pro-Mia are resources with a clear intention to establish a contact with people with an eating disorder or who are at risk for developing one, in order to strengthen the communication through the blogosphere. [ABSTRACT FROM AUTHOR]

Abstract: A temperature shift-up induces extra rounds of fully replicated chromosomes in Escherichia coli and leads to an increase in DNA/mass ratio. In the present work we characterize the requirements for this heat-induced replication (HIR) with respect to replisome components, replication restart, and recombination functions. We found that HIR requires Klenow and 5′–3′ exonuclease activities from Pol I and Pol III, but does not require translesion synthesis polymerases. We also found that replication restart is PriA–PriB pathway dependent. The dnaC809 allele suppresses the dependency on PriA, confirming the requirement for primosome assembly, in which PriA helicase function is not required. Rep helicase and the replication-associated function of RecA were found to be essential. HIR has low recombination requirements, and no DSBs are generated by heat stress. We propose that the Pol I-dependent replisome in HIR, which gives a slow replication speed, is more unstable and disassembles more frequently than normal replisome. Rep and RecA would be required to stabilize HIR replication forks. Since neither D-loops nor R-loops support HIR restart, the PriA–PriB pathway must reload the replisome by a direct restart mechanism from a 3′-end of a nascent leading strand. [Copyright &y& Elsevier]

An upshift of 10°C or more in the growth temperature of an Escherichia coli culture causes induction of extra rounds of chromosome replication. This stress replication initiates at oriC but has functional requirements different from those of cyclic replication. We named this phenomenon heat-induced replication (HIR). Analysis of HIR in bacterial strains that had complete or partial oriC deletions and were suppressed by F integration showed that no sequence outside oriC is used for HIR. Analysis of a number of oriC mutants showed that deletion of the L-13-mer, which makes oriC inactive for cyclic replication, was the only mutation studied that inactivated HIR. The requirement for this sequence was strictly correlated with Benham's theoretical stress-induced DNA duplex destabilization. oriC mutations at DnaA, FIS, or IHF binding sites showed normal HIR activation, but DnaA was required for HIR. We suggest that strand opening for HIR initiation occurs due to heat-induced destabilization of the L-13-mer, and the stable oligomeric DnaA-single-stranded oriC complex might be required only to load the replicative helicase DnaB. [ABSTRACT FROM AUTHOR]

Physical exercise is a tool to prevent and treat some of the chronic diseases affecting the world’s population. A mechanism through which exercise could exert beneficial effects in the body is by provoking alterations to the gut microbiota, an environmental factor that in recent years has been associated with numerous chronic diseases. Here we show that physical exercise performed by women to at least the degree recommended by the World Health Organization can modify the composition of gut microbiota. Using high-throughput sequencing of the 16s rRNA gene, eleven genera were found to be significantly different between active and sedentary women. Quantitative PCR analysis revealed higher abundance of health-promoting bacterial species in active women, including Faecalibacterium prausnitzii, Roseburia hominis and Akkermansia muciniphila. Moreover, body fat percentage, muscular mass and physical activity significantly correlated with several bacterial populations. In summary, we provide the first demonstration of interdependence between some bacterial genera and sedentary behavior parameters, and show that not only does the dose and type of exercise influence the composition of gut microbiota, but also the breaking of sedentary behavior. [ABSTRACT FROM AUTHOR]

Recent studies have revealed the importance of the gut microbiota in the regulation of metabolic phenotypes of highly prevalent metabolic diseases such as obesity, type II diabetes mellitus (T2DM) and cardiovascular disease. Peroxisome proliferator-activated receptors (PPARs) are a family of ligand-activated nuclear receptors that interact with PPAR-γ co-activator-1α (PPARGC1A) to regulate lipid and glucose metabolism. Genetic polymorphisms in PPARD (rs 2267668; A/G) and PPARGC1A (rs 8192678; G/A) are linked to T2DM. We studied the association between the single-nucleotide polymorphisms (SNPs) rs 2267668 and rs 8192678 and microbiota signatures and their relation to predicted metagenome functions, with the aim of determining possible microbial markers in a healthy population. Body composition, physical exercise and diet were characterized as potential confounders. Microbiota analysis of subjects with PPARGC1A (rs 8192678) and PPARD (rs 2267668) SNPs revealed certain taxa associated with the development of insulin resistance and T2DM. Kyoto encyclopedia of gene and genomes analysis of metabolic pathways predicted from metagenomes highlighted an overrepresentation of ABC sugar transporters for the PPARGC1A (rs 8192678) SNP. Our findings suggest an association between sugar metabolism and the PPARGC1A rs 8192678 (G/A) genotype and support the notion of specific microbiota signatures as factors related to the onset of T2DM. [ABSTRACT FROM AUTHOR]

Sequencing the 16S gene rRNA has become a popular method when identifying bacterial communities. However, recent studies address differences in the characterization based on sample preparation, sequencing platforms, and data analysis. In this work, we tested some of the available user-friendly protocols for data analysis with the reads obtained from the sequencing machines Illumina MiSeq and Ion Torrent Personal Genome Machine (PGM). We sought for the advantages and disadvantages of both platforms in terms of accuracy, detected species, and abundance, analyzing a staggered mock community. Four different pipelines were applied: QIIME 1.9.1 with default parameters, QIIME 1.9.1 with modified parameters and chimera removal, VSEARCH 2.3.4, and QIIME 2 v.2018.2. To address the limitations of species level detection we used species-classifier SPINGO. The optimal pipeline for PGM platform, was the use of QIIME 1.9.1 with default parameters (QIIME1), except when a study requires the detection of Bacteroides or other Bacteroidaceae members, in which QIIME1MOD (with chimera removal) seems to be a good alternative. For Illumina Miseq, VSEARCH strategy can be a good option. Our results also confirm that all the tested pipelines can be used for metagenomic analysis at family and genus level. • 16S rRNA short-read sequence data gene presents limitations at species level. • For metagenomic analysis up to genus level, most classifiers perform well. • SPINGO classifier is useful to address the limitations at species level. • For PGM data, the optimal pipeline was QIIME 1.9.1 with default parameters. • All the protocols implemented in QIIME performed well for Illumina data. [ABSTRACT FROM AUTHOR]