A high-throughput DNA sequencing study of fecal bacteria of seven Mexican horse breeds.

Horses are non-ruminant, herbivorous mammals, been used through history for various purposes, with a gut microbiota from cecum to the colon, possessing remarkable fermentative capacity. We studied the fecal microbiota of Azteca, Criollo, Frisian, Iberian, Pinto, Quarter and Spanish horse breeds living in Mexico by next-generation DNA sequencing of 16S rRNA gene libraries. Dominant phyla Firmicutes, Bacteroidetes, Proteobacteria, Spirochaetes, Fibrobacteres, Actinobacteria and Verrucomicrobia have different relative abundances among breeds, with contrasted alpha and beta diversities as well. Heatmap analysis revealed that Ruminococcaceae, Lachnospiraceae, Mogibacteriaceae families, and order Clostridiales are more abundant in Spanish, Azteca, Quarter and Criollo breeds. The LEfSe analysis displayed higher abundance of order Bacteroidales, family BS11, and genera Faecalibacterium, Comamonas, Collinsella, Acetobacter, and Treponema in Criollo, Azteca, Iberian, Spanish, Frisian, Pinto, and Quarter horse breeds. The conclusion is that dominant bacterial taxa, found in fecal samples of horse breeds living in Mexico, have different relative abundances.

Gut microbiome production of short-chain fatty acids and obesity in children.

Obesity has been a worldwide multifactorial epidemic malady for the last 2 decades. Changes in gut microbiota composition and its metabolites - short-chain fatty acids (SCFAs) - have been associated with obesity. Recent evidence suggests that SCFAs made by the gut microbiota may regulate directly or indirectly physiological and pathological processes in relation to obesity. We review the influence of gut microbiota in energy, glucose, and lipid homeostasis control via their metabolites. Gut microbial disturbances in obese children may have a role in their metabolism. At first glance, excessive short-chain fatty acids produced by a particular gut microbiota represent an additional energy source, and should cause an imbalance in energy regulation, contributing to obesity. However, simultaneously, SCFA participates in glucose-stimulated insulin secretion from the pancreatic ß-cells through interaction with the FFA2 and FFA3 receptors, and release of peptide hormones which control appetite. This apparent contradictory situation may indicate the involvement of additional particular bacteria or bacterial components or metabolites that may trigger regulatory cascades by interaction with some G-protein-coupled membrane receptors.

Airborne Bacterial Diversity from the Low Atmosphere of Greater Mexico City.

Greater Mexico City is one of the largest urban centers in the world, with an estimated population by 2010 of more than 20 million inhabitants. In urban areas like this, biological material is present at all atmospheric levels including live bacteria. We sampled the low atmosphere in several surveys at different points by the gravity method on LB and blood agar media during winter, spring, summer, and autumn seasons in the years 2008, 2010, 2011, and 2012. The colonial phenotype on blood agar showed α, ß, and γ hemolytic activities among the live collected bacteria. Genomic DNA was extracted and convenient V3 hypervariable region libraries of 16S rDNA gene were high-throughput sequenced. From the data analysis, Firmicutes, Proteobacteria, and Actinobacteria were the more abundant phyla in all surveys, while the genera from the family Enterobacteriaceae, in addition to Bacillus spp., Pseudomonas spp., Acinetobacter spp., Erwinia spp., Gluconacetobacter spp., Proteus spp., Exiguobacterium spp., and Staphylococcus spp. were also abundant. From this study, we conclude that it is possible to detect live airborne nonspore-forming bacteria in the low atmosphere of GMC, associated to the microbial cloud of its inhabitants.

PTB binds to the 3' untranslated region of the human astrovirus type 8: a possible role in viral replication.

The 3' untranslated region (3'UTR) of human astroviruses (HAstV) consists of two hairpin structures (helix I and II) joined by a linker harboring a conserved PTB/hnRNP1 binding site. The identification and characterization of cellular proteins that interact with the 3'UTR of HAstV-8 virus will help to uncover cellular requirements for viral functions. To this end, mobility shift assays and UV cross-linking were performed with uninfected and HAstV-8-infected cell extracts and HAstV-8 3'UTR probes. Two RNA-protein complexes (CI and CII) were recruited into the 3'UTR. Complex CII formation was compromised with cold homologous RNA, and seven proteins of 35, 40, 45, 50, 52, 57/60 and 75 kDa were cross-linked to the 3'UTR. Supermobility shift assays indicated that PTB/hnRNP1 is part of this complex, and 3'UTR-crosslinked PTB/hnRNP1 was immunoprecipitated from HAstV-8 infected cell-membrane extracts. Also, immunofluorescence analyses revealed that PTB/hnRNP1 is distributed in the nucleus and cytoplasm of uninfected cells, but it is mainly localized perinuclearly in the cytoplasm of HAstV-8 infected cells. Furthermore, the minimal 3'UTR sequences recognized by recombinant PTB are those conforming helix I, and an intact PTB/hnRNP1-binding site. Finally, small interfering RNA-mediated PTB/hnRNP1 silencing reduced synthesis viral genome and virus yield in CaCo2 cells, suggesting that PTB/hnRNP1 is required for HAstV replication. In conclusion, PTB/hnRNP1 binds to the 3'UTR HAstV-8 and is required or participates in viral replication.

Detection and sequencing of defective viral genomes in C6/36 cells persistently infected with dengue virus 2.

Dengue virus is the most important arbovirus that affects humans, and it can establish persistent infections, especially in insect-derived cell cultures. Defective viral genomes have been implicated in the establishment and maintenance of persistent infections with several flaviviruses; however, there exists almost no information concerning defective dengue virus genomes. Here, we report the detection of defective dengue 2 virus genomes in persistently infected mosquito C6/36 cells. The defective viral genomes were detected at a low ratio compared with the wild-type genome. Deletions of approximately 147 residues (222-368) were found in the E protein, and these mainly affected domain III (73 %) of the protein; deletions of approximately 153 residues (4-156) and 228 residues (597-825) were found in the methyltransferase and polymerase domains, respectively, of the NS5 protein. The truncated versions of NS5 could be detected by western blot only in the protein extracts derived from persistently infected cells.