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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.

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In healthy women at reproductive age, the vaginal microbiota is mainly dominated by Lactobacillus bacteria during pregnancy and non-pregnancy stages. However, little is known about longitudinal changes within the vaginal microbiota composition from the third trimester of pregnancy to childbirth in healthy women. Thus, we conducted an exploratory longitudinal study of vaginal microbiota composition of 10 Mexican pregnant women, sampling from the same volunteer at two-time points: third trimester of pregnancy and active childbirth. Vaginal bacterial microbiota was characterized by V3-16S rDNA libraries by high-throughput sequencing and bioinformatics methods. Out of ten, vaginal microbiota from eight women was dominated by the Lactobacillus genus at both time points, whereas the other two women showed vaginal microbiota composition with high abundance of genera Gardnerella, Prevotella, and members of the Atopobiaceae family, without any preterm birth correlation. Importantly, we found no statistically significant differences in relative abundances, absolute reads count, alpha and beta diversity between the third trimester of pregnancy, and active childbirth time points. However, compared to the third trimester of pregnancy, we observed a trend with higher absolute reads counts for Gardnerella, Faecalibaculum, Ileibacterium, and Lactococcus genus at active childbirth and lower absolute reads count of Lactobacillus genus. Our results suggest that the vaginal microbiota composition is stable, and Lactobacillus genus is the dominant taxa in Mexican women's vagina at the third trimester of pregnancy and childbirth.

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PURPOSE: The aim of the present work was to assess the electrogenic activity of bacteria from hydrothermal vent sediments achieved under sulfate reducing (SR) conditions in a microbial fuel cell design with acetate, propionate and butyrate as electron donors. METHODS: Two different mixtures of volatile fatty acids (VFA) were evaluated as the carbon source at two chemical oxygen demand (COD) proportions. The mixtures of VFA used were: acetate, propionate and butyrate COD: 3:0.5:0.5 (stage 1) and acetate - butyrate COD: 3.5:0.5 (stage 2). Periodical analysis of sulfate (SO4 -2), sulfide (HS-) and COD were conducted to assess sulfate reduction (SR) and COD removal along with measurements of voltage and current to assess the global performance of the consortium in the system. RESULTS: Percentage of SR was of 97.5 ± 0.7 and 74.3 ± 1.5% for stage 1 and 2, respectively. The % COD removal was of 91 ± 2.1 and 75.3 ± 9.6 for stage 1 and 2, respectively. Although SR and COD removal were higher at stage 1, in regards of energy, stage 2 presented higher current and power densities and Coulombic efficiency as follows: 741.7 ± 30.5 µA/m2, 376 ± 34.4 µW/m2 and 5 ± 2.7%, whereas for stage 1 these values were: 419 ± 71 µA/m2, 52.7 ± 18 µW/m2 and 0.02%, respectively. A metagenomic analysis - stage 2 - in the anodic chamber, demonstrated that SR was due to Dethiosulfovibrionaceae (HA73), Desulfobacter and Desulfococcus and the electrogenic microorganisms were Planococcus, SHD-231, Proteiniclasticum, vadinCA02, and families Porphyromonadacea and Pseudomonadaceae. CONCLUSIONS: It was demonstrated that microorganisms prevenient from hydrothermal vent sediments adapted to a microbial fuel cell system are able to generate electricity coupled to 74.3 ± 1.5 and 75.3 ± 9.6% of SR and COD removal respectively, with a mixture of acetate - butyrate.

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A paramour factor limiting metal-microorganism interaction is the metal ion concentration, and the metal precipitation efficiency driven by microorganisms is sensitive to metal ion concentration. The aim of the work was to determine the tolerance of the sulfidogenic sludge generated from hydrothermal vent sediments at microcosms level to different concentrations of Fe, Cu and Zn and the effect on the microbial community. In this study the chemical oxygen demand (COD) removal, sulfate-reducing activity (SRA) determination, inhibition effect through the determination of IC50, and the characterization of the bacterial community´s diversity were conducted. The IC50 on SRA was 34 and 81 mg/L for Zn and Cu, respectively. The highest sulfide concentration (H2S mg/L) and % of sulfate reduction obtained were: 511.30 ± 0.75 and 35.34 ± 0.51 for 50 mg/L of Fe, 482.48 ± 6.40 and 33.35 ± 0.44 for 10 mg/L of Cu, 442.26 ± 17.1 and 30.57 ± 1.18 for 10 mg/L of Zn, respectively. The COD removal rates were of 71.81 ± 7.6, 53.92 ± 1.07 and 57.68 ± 10.2 mg COD/ L d for Fe (50 mg/L), Cu (40 mg/L) and Zn (20 mg/L), respectively. Proteobacteria, Firmicutes, Chloroflexi and Actinobacteria were common phyla to four microcosms (stabilized sulfidogenic and added with Fe, Cu or Zn). The dsrA genes of Desulfotomaculum acetoxidans, Desulfotomaculum gibsoniae and Desulfovibrio desulfuricans were expressed in the microcosms supporting the SRA results. The consortia could be explored for ex-situ bioremediation purposes in the presence of the metals tested in this work.

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Obesity is an excessive fat accumulation that could lead to complications like metabolic syndrome. There are reports on gut microbiota and metabolic syndrome in relation to dietary, host genetics, and other environmental factors; however, it is necessary to explore the role of the gut microbiota metabolic pathways in populations like Mexicans, where the prevalence of obesity and metabolic syndrome is high. This study identify alterations of the gut microbiota in a sample of healthy Mexican women (CO), women with obesity (OB), and women with obesity plus metabolic syndrome (OMS). We studied 67 women, characterizing their anthropometric and biochemical parameters along with their gut bacterial diversity by high-throughput DNA sequencing. Our results indicate that in OB or OMS women, Firmicutes was the most abundant bacterial phylum. We observed significant changes in abundances of bacteria belonging to the Ruminococcaceae, Lachnospiraceae, and Erysipelotrichaceae families and significant enrichment of gut bacteria from 16 different taxa that might explain the observed metabolic alterations between the groups. Finally, the predicted functional metagenome of the gut microbiota found in each category shows differences in metabolic pathways related to lipid metabolism. We demonstrate that Mexican women have a particular bacterial gut microbiota characteristic of each phenotype. There are bacteria that potentially explain the observed metabolic differences between the groups, and gut bacteria in OMS and OB conditions carry more genes of metabolic pathways implicated in lipid metabolism.

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Obesity is a metabolic disorder and global health issue. In Mexico 34.4% of children between 5 and 11 years-old are overweight or obese. Here we address this issue studying the gut microbiome in a sample of Mexican children affected by obesity. We performed metagenomic shotgun-sequencing of DNA isolated from fecal samples from a cohort of normal weight and obese Mexican children using Illumina platform with HiSeq 2500. We also examined their metabolic factors and fecal short-chain fatty acids concentration. The results show that a remarkable dysbiosis of bacteria, archaea and viruses was not observed in the obese children group compared to the normal weight group; however, the archaeal community exhibited an increase of unclassified Methanobrevibacter spp. in obese children. The bacterial communities of all participants were clustered into three different enterotypes. Most normal weight children have a gut bacterial community dominated by Ruminococcus spp. (Enterotype 3), while most obese children had a community dominated by Prevotella spp. (Enterotype 2). On the other hand, changes in the gut microbiome were correlated with clinical metadata and could be used to stratify individuals based on their phenotype. The species Megamonas spp. were over-represented in obese children, whereas members of the family Oscillospiraceae were depleted in the same individuals and negatively correlated with levels of serum cholesterol. A microbiome comparative metabolic pathway analysis showed that two KEGG pathway modules of glycolysis, Glycolysis I (from Glucose 6-Phosphate), and Glycolysis II (from Fructose 6-Phosphate) were significantly overrepresented in normal weight children. Our results establish specific alterations in the gut microbiome of Mexican children affected of obesity, along with clinical alterations, providing information on the microbiome composition that may be useful for prognosis, diagnosis, and treatment.

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Obesity is a metabolic disease characterized by low-grade inflammation and accompanied by dyslipidemia and up-regulation of other bioactive molecules, creating a predisposition to endothelial dysfunction and metabolic syndrome. We studied the association between gut microbiota diversity and endothelial dysfunction (EDF) markers in obese Mexican children and adolescents. We examined clinical data including metabolic factors and EDF markers in blood samples. Gut bacterial diversity was characterized by high-throughput sequencing of V3-16S rDNA libraries. Triglycerides, insulin, homeostasis model assessment-insulin resistant (HOMA-IR), leptin, C-reactive protein (CRP), and EDF marker intercellular adhesion molecule 1 (ICAM-1) were significantly higher in obese children and adolescents. Multivariate analysis showed statistically significant positive associations between vascular cell adhesion molecule 1 (VCAM-1) and Veillonellaceae, and between ICAM-1 and Ruminococcus in obese children. In obese adolescents, there was a statistically significant positive association between total cholesterol and Ruminococcus, and between ICAM-1 and Bacteroides. LEfSe analysis showed that the genus Lactobacillus and family Coriobacteriaceae were enriched in children, and genera Collinsella and Prevotella were enriched in obese adolescents. Obese children and adolescents had higher levels of insulin resistance and metabolic syndrome. These results suggest that obese Mexican children and adolescents had increased levels of CRP and a reduction of adiponectin, which causes higher expression of EDF markers, affecting endothelial function and associating with changes in the gut microbiota.

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Cheese is a live food whose preparation involves procedures and microbial communities playing an important role for the final product. We characterized the bacterial and fungal diversity of seventeen different Mexican cheeses by high-throughput DNA sequencing of 16S/18S rDNA libraries. We propose the existence of bacterial and fungal core communities, where at genera level, bacteria include Streptococcus spp., Lactococcus spp., Lactobacillus spp., Aerococcus spp., and Weisella spp. while at species level, the fungal community includes Galactomyces reessii, Scheffersomyces stipitis, Saccharomyces cerevisiae (baker's yeast), and S. cerevisiae_rm11-1a. In addition to the bacterial and fungal core communities, we found members of the cheese microbiota that could be associated to other factors of the cheese manufacturing process. Co-occurrence analysis made in this work, indicates that bacterial and fungal communities maintain positive and negative interactions which are important to shape the resident microbial communities in cheeses. This work is a contribution to the description of the microbial diversity found in some Mexican cheeses.

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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.

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